USOO7604751B2

(12) United States Patent (10) Patent No.: US 7,604,751 B2 Yoneda et al. (45) Date of Patent: Oct. 20, 2009

(54) POLISHING LIQUID COMPOSITION 5,741,765 A 4/1998 Leach ...... 510,123 5,783,489 A * 7/1998 Kaufman et al...... 438,692 (75) Inventors: Yasuhiro Yoneda, Wakayama (JP); 5,916,855 A 6/1999 Avanzino et al.

Ryoichi Hashimoto, Wakayama (LP): WW - A . C. S.allal Gal. m...... Toshiya Hagihara, Wakayama (JP) 6,136,711 A * 10/2000 Grumbine et al...... 438,692 6,383,240 B1 5, 2002 Nishimoto et al. (73) Assignee: Kao Corporation, Tokyo (JP) 6,447,563 B1* 9/2002 Mahulikar ...... 51.309 (*) Notice: Subject to any disclaimer, the term of this FOREIGN PATENT DOCUMENTS patent is extended or adjusted under 35 EP O 811 665 12/1997 U.S.C. 154(b) by 142 days. JP 11 116942 4f1999 JP 11-116948 A 4f1999 (21) Appl. No.: 11/434,074 JP 2000-252243 A 9, 2000 JP 2001-187877 T 2001 (22) Filed: May 16, 2006 WO WOOOOO561 A1 1, 2000 WO WOOO,398.44 T 2000 (65) Prior Publication Data OTHER PUBLICATIONS US 2006/024O672 A1 Oct. 26, 2006 U.S. Appl. No. 60/105.366, filed Oct. 23, 1998, by Malulikar, priority Related U.S. Application Data filing for USPN 6447,563, noted above.* Chemindustry.com; Synonyms for CAS Registry 6419-19-8; May 8, (62) Division of application No. 10/030,424, filed as appli 2005.* cation No. PCT/JP00/04571 on Jul. 7, 2000, now Pat. U.S. Appl. No. 1 1/544,694, filed Oct. 10, 2006, Yoneda, et al. No. 7,118,685. H. Duncan, et al., “Polishing composition for calcium fluoride—comprises acqueous iron(III) salt Sollution containing alco (30) Foreign Application Priority Data hol”, English Abstract of DD 249489A, May 26, 1986, 2 pp. Jul. 13, 1999 (JP) ...... 11-198263 * cited by examiner Feb. 8, 2000 (JP) ...... 2OOO-O3O477 Primary Examiner Keith D Hendricks (51) Int. Cl. Assistant Examiner—Patricia A George HOIL 2/302 (2006.01) (74) Attorney, Agent, or Firm Oblon, Spivak, McClelland, (52) U.S. Cl...... 216/88; 216/89; 252/79.1 Maier & Neustadt, L.L.P. (58) Field of Classification Search ...... 438/692; (57) ABSTRACT 252/79.1, 79.4; 216/88 See application file for complete search history. A polishing liquid composition is applicable as a means of (56) References Cited forming embedded metal interconnections on a semiconduc tor Substrate. In a surface to be polished comprising an insu U.S. PATENT DOCUMENTS lating layer and a metal interconnection layer, the polishing liquid composition is capable of maintaining a polishing 2,892,796 A 6, 1959 McCune 4,141,850 A 2f1979 Readio et al. speed of the metal layer, of suppressing an etching speed, and 4,158,593. A 6, 1979 Allan et al. of preventing dishing of the metal layer. 5,209,820 A * 5/1993 Tytgatet al...... 216,108 5,496.485 A 3/1996 Maternaghan 12 Claims, No Drawings US 7,604,751 B2 1. 2 POLISHING LIQUID COMPOSITION layer made of copper or the like is polished, there arises Surface roughening of the copper Surface caused by ammo TECHNICAL FIELD nium polyacrylate. An object of the present invention is to provide a polishing The present invention relates to a polishing liquid compo 5 liquid composition capable of maintaining a polishing speed sition for polishing a surface to be polished comprising an of a metal film, Suppressing an etching speed, and having an insulating layer and a metal layer. More specifically, the excellent prevention effect such as dishing of the metal inter present invention relates to a polishing liquid composition connection layer, in a surface to be polished comprising an which is applicable as a means of forming embedded metal insulating layer and a metal layer, a process for polishing; and interconnection on a semiconductor Substrate, a process for 10 a process for manufacturing a semiconductor Substrate. polishing, and a process for manufacturing a semiconductor These objects and other objects of the present invention substrate. will be apparent from the following description.

BACKGROUND ART DISCLOSURE OF INVENTION 15 In the process for manufacturing a semiconductor device, Specifically, the present invention relates to: comprising the steps of forming interconnection-shaped 1 a polishing liquid composition for polishing a surface to recesses on a Surface of the insulating film on a semiconduc be polished comprising an insulating layer and a metal tor Substrate, sedimenting a metal film made of copper or the layer, the polishing liquid composition comprising a com like on the insulating film having the recesses, and Subjecting pound having a structure in which each of two or more the metal film to polishing treatment by a polishing device adjacent carbonatoms has a hydroxyl group in a molecule, and a polishing liquid, thereby allowing the metal layer to and water (hereinafter also referred to “the polishing liquid remain only in the recesses to form a metal interconnection composition 1-1'); layer, wherein Metal Chemical Mechanical Polishing (here 2 a polishing liquid composition for polishing a surface to inafter simply referred to as “metal CMP) is employed for 25 be polished comprising an insulating layer and a metal the process of polishing. layer, the polishing liquid composition comprising an ali However, in the metal CMP, there arise grooves so-called phatic carboxylic acid having 7 to 24 carbonatoms and/or dishing on the metal interconnection layer in the recesses of a salt thereof, an etching agent, and water (hereinafter also the insulating film, so that the cross-sectional area of the referred to “the polishing liquid composition 1-2); metal interconnection layer is reduced, thereby causing an 30 3 a polishing liquid composition for polishing a surface to increase in electric resistivity. This dishing is caused by more be polished comprising an insulating layer and a metal excessive polishing or etching of the Surface of the metal layer, the polishing liquid composition comprising an interconnection layer than that of the insulating film Surface amine compound represented by the following general for by the polishing liquid composition. Especially copper, one mula (II): of the main metal interconnection, has defects of being exces 35 sively etched by the polishing liquid composition, so that the dishing is likely to be caused. (II) Therefore, there has been desired a polishing liquid com position free from defects Such as dishing in the metal layer during the formation of interconnection, with retaining an 40 V etching action for polishing the metal film on the insulating film. As a conventional polishing liquid, for instance, Japanese wherein R is a linear or branched alkyl group having 4 to 18 Patent Laid-Open Nos. Hei 8-83780 and Hei 11-21546 each 45 carbon atoms, a linear or branched alkenyl group having 4 to discloses a polishing liquid comprising benzotriazole or a 18 carbon atoms, an aryl group having 6 to 18 carbon atoms, derivative thereofas a protective film-forming agent for the and an aralkyl group having 7 to 18 carbonatoms; each of R' metal surface in order to prevent the dishing. Since the formed and R, which may be identical or different, is hydrogenatom, protective film is rigid, when the metal layer is polished in the a linear alkyl group having 1 to 8 carbon atoms or a branched metal CMP, the polishing speed would become insufficient. 50 alkyl group having 3 to 8 carbon atoms, or a group repre In addition, Japanese Patent Laid-Open No. Hei 11-116942 sented by H-(OR), , wherein Risalinear alkylenegroup discloses a composition for polishing, comprising a com having 1 to 3 carbon atoms, or a branched alkylene group pound having 1 to 10 alcoholic hydroxyl groups, or a nitro gen-containing basic compound having 1 to 10 alcoholic having 3 carbon atoms; and Z is a number of 1 to 20, hydroxyl groups. This composition for polishing has a pur 55 and/or a salt thereof, an etching agent, and water (hereinafter pose of reducing particles deposited on a wafer Surface in also referred to “the polishing liquid composition 1-3); final polishing of the semiconductor wafer, so that the prob 4 the polishing liquid composition according to any one of lems to be solved are different. items 1 to 3 above, further comprising an oxidizing In addition, Japanese Patent Laid-OpenNo. Hei 10-44047 agent (hereinafter also referred to “the polishing liquid discloses a polishing liquid comprising an aqueous medium, 60 composition 2'); an abrasive, an oxidizing agent, and an organic acid. How 5the polishing liquid composition according to any one of ever, since the etching action is too strong, the prevention for items 1 to 4 above, further comprising an abrasive dishing would be insufficient. Further, Japanese Patent Laid (hereinafter also referred to “the polishing liquid compo Open No. Hei 11-195628 discloses a process for polishing in sition 3'); which a polishing liquid is used in combination with ammo 65 6 a process for polishing a semiconductor Substrate, com nium polyacrylate as a Substance for Suppressing oxidation prising polishing a surface to be polished comprising an and etching. However, in the metal CMP in which a metal insulating layer and a metal layer using the polishing liquid US 7,604,751 B2 3 4 composition of any one of items 1 to 5, thereby smooth which each of two or more adjacent carbon atoms has a ening the semiconductor Substrate; and hydroxyl group is present in the terminal portion of a mol 7 a process for manufacturing a semiconductor Substrate ecule. comprising polishing a surface to be polished comprising Examples thereof include a compound represented by the an insulating layer and a metal layer using the polishing formula (I): liquid composition of any one of items 1 to 5, thereby Smoothening the semiconductor Substrate. R' X-(CH2) [CH(OH)1, CH-OH (I) wherein R' is a hydrocarbon group having 1 to 24 carbon BEST MODE FOR CARRYING OUT THE atoms: X is a group represented by (CH), wherein m is 0 or INVENTION 10 1. oxygen atom, Sulfur atom, COO group, OCO group, a As mentioned above, the polishing liquid composition of group represented by NR or O(RO)P(O)O, wherein R is the present invention is a polishing liquid composition for hydrogenatom or a hydrocarbon group having 1 to 24 carbon polishing a surface to be polished comprising an insulating atoms; q is 0 or 1; and n is an integer of 1 to 4. layer and a metal layer, and has the following three embodi 15 In the formula (I), the hydrocarbon group of R' may be mentS. either aliphatic or aromatic group, and the aliphatic group is Embodiment 1: A polishing liquid composition comprising a preferable. The structure of the aliphatic group may be satu compound having a structure in which each of two or more rated or unsaturated, or linear or branched. From the view adjacent carbonatoms has a hydroxyl group in a molecule, point of Suppressing dishing, a saturated structure is prefer and water. able, and a linear structure is preferable. In addition, the Embodiment 2: A polishing liquid composition comprising number of carbon atoms of the above hydrocarbon groups is an aliphatic carboxylic acid having 7 to 24 carbon atoms preferably 1 or more, from the viewpoint of suppressing the and/or a salt thereof, an etching agent and water. dishing, and the number of carbon atoms is preferably 24 or Embodiment 3: A polishing liquid composition comprising less, from the viewpoint of the solubility of the compound an amine compound represented by the following general 25 represented by the formula (I) in water. The number of carbon atoms is more preferably from 1 to 18, still more preferably formula (II): from 2 to 12. Each of mand q is preferably 1. The number of carbonatoms of R is preferably 12 or less, more preferably 8 or less, still more preferably 4 or less, from the viewpoint of (II) suppressing the dishing. Especially, R is preferably hydro 30 gen atom or methyl group. n is preferably 2 or less, more preferably 1, from the viewpoint of suppressing the dishing. In addition, the hydroxyl group-containing compound may have various functional groups other than hydroxyl group in a molecule. From the viewpoints of maintaining the polishing wherein R is a linear or branched alkyl group having 4 to 18 35 speed and Suppressing the dishing, those compounds which carbon atoms, a linear or branched alkenyl group having 4 to do not contain carboxyl group, Sulfonate group, primary 18 carbon atoms, an aryl group having 6 to 18 carbon atoms, amino group or phenolic hydroxyl group are preferable. and anaralkyl group having 7 to 18 carbon atoms; and each of The hydroxyl group-containing compound has a molecular R" and R, which may be identical or different, is hydrogen 40 weight of preferably 5000 or less, more preferably 1000 or atom, a linear alkyl group having 1 to 8 carbon atoms or a less, especially preferably 500 or less, from the viewpoints of branched alkyl group having 3 to 8 carbon atoms, or a group represented by H-(OR), , wherein R is a linear alkylene maintaining the polishing speed and Suppressing the dishing. group having 1 to 3 carbon atoms, or a branched alkylene The hydroxyl group-containing compound has an acid dis group having 3 carbon atoms; and Z is a number of 1 to 20, Sociation constant pKa in an aqueous solution of preferably 8 45 or more, more preferably 9 or more, especially preferably 10 and/or a salt thereof, an etching agent, and water. or more, from the viewpoints of maintaining the polishing speed and Suppressing the dishing. However, in a case where EMBODIMENT 1 the hydroxyl group-containing compound has two or more dissociable functional groups in a molecule, pKa referred In this embodiment, one of the great features resides in the 50 herein is a first dissociation constant. In addition, the Solubil use of a compound having a structure in which each of two or ity of the hydroxyl group-containing compound at a pH more adjacent carbon atoms has a hydroxyl group in a mol usable for a polishing liquid composition is such that the ecule (hereinafter simply referred to as “hydroxyl group compound dissolves preferably at 0.5% by weight or more, containing compound'). By the use of the polishing liquid more preferably at 1.0% by weight or more, in water at 25°C., composition comprising the hydroxyl group-containing com 55 from the viewpoint of formulating the hydroxyl group con pound, the polishing speed can be maintained, and excessive taining compound in an aqueous medium. etching of a metal film in the metal layer can be prevented, so Concrete examples of these hydroxyl group-containing that there is exhibited an excellent effect that a polishing compounds include alkanediols such as 1.2-butanediol. 1.2- Surface without defects such as dishing can be obtained. heptanediol, 1.2-hexanediol (“a” in Table 1 mentioned In the hydroxyl group-containing compound, from the 60 below), and 1.2-octanediol; alkanetriols such as 1,2,3-hexan viewpoint of maintaining the polishing speed and Suppress etriol, 1.2,6-hexanetriol, and 1.2.3-heptanetriol: glyceryl ing dishing, the number of adjacent carbon atoms having a ethers such as butyl glyceryl ether (“b' in Table 1 mentioned hydroxyl group in a molecule is 2 or more, preferably from 2 below), pentylglyceryl ether, hexyl glyceryl ether, and octyl to 10, more preferably from 2 to 7, especially preferably from glyceryl ether, monoglycerides such as glyceryl monobu 2 to 4. 65 tanoate, glyceryl monopentanoate, glyceryl monohexanoate, In addition, as the structure of the hydroxyl group-contain glyceryl monoheptanoate (“c” in Table 1 mentioned below), ing compound, it is particularly preferable that the structure in and glyceryl monooctanoate; partially esterified products US 7,604,751 B2 5 6 prepared by carrying out esterification reaction of gluconic acid, butyric acid, Valerianic acid, caproic acid, and pyruvic acid and an alcohol Such as hexyl alcohol; compounds pre acid; dicarboxylic acids such as oxalic acid, malonic acid, pared by reacting glycidol with a monoalkylamine Such as Succinic acid, glutaric acid, and adipic acid; hydroxycarboxy hexylamine or a dialkylamine Such as dipropylamine ('d' in lic acids Such as gluconic acid, tartaric acid, glycolic acid, Table 1 mentioned below); diesters of tartaric acid such as 5 lactic acid, citric acid, and malic acid; aminocarboxylic acid diethyl tartrate, dibutyl tartrate, dipropyl tartrate ('e' in Table Such as nitrilotriacetic acid. The organic acid having phos 1 mentioned below), and dihexyl tartrate; 1.2-cyclohex phonic group includes aminotri (methylenephosphonic acid), anediol, and the like. Among them, from the viewpoints of 1-hydroxyethylidene-1,1-diphosphonic acid, ethylenedi maintaining the polishing speed and Suppressing the dishing, aminetetra(methylenephosphonic acid), hexamethylenedi the alkanediols and the glyceryl ethers are preferable. These 10 aminetetra(methylenephosphonic acid), diethylenetriamine hydroxyl group-containing compounds may be used alone or penta(methylenephosphonic acid); the organic acid having in admixture of two or more kinds. phosphinic group includes ethyl phosphite, and the like; the The amount of the hydroxyl group-containing compounds organic acid having Sulfonic group includes methanesulfonic formulated is preferably from 0.01 to 30% by weight, more acid, benzenesulfonic acid, p-toluenesulfonic acid, naphtha preferably from 0.05 to 5% by weight, still more preferably 15 lenesulfonic acid, and the like; the organic acid having from 0.1 to 3% by weight, of the polishing liquid composition Sulfinic group includes benzenesulfinic acid, p-toluene 1-1, from the viewpoints of maintaining the polishing speed Sulfinic acid, and the like. Among them, the organic acids and Suppressing the dishing. having carboxyl group are preferable. More concretely, Water usable in this embodiment is used as a medium. Its monocarboxylic acids, dicarboxylic acids, hydroxycarboxy amount formulated is preferably from 60 to 99.99% by lic acids and aminocarboxylic acids are preferable, and acetic weight, more preferably from 70 to 99.4% by weight, still acid, oxalic acid, Succinic acid, glycolic acid, lactic acid, more preferably from 80 to 99.0% by weight, of the polishing citric acid, malic acid, tartaric acid, gluconic acid and nitrilo liquid composition 1-1, from the viewpoint of efficiently triacetic acid are more preferable, and glycolic acid and glu polishing the substrate to be polished. conic acid are still more preferable. These organic acids may The polishing liquid composition 1-1 of this embodiment 25 be used alone or in admixture of two or more kinds. having the composition described above has a pH of prefer The organic acid is used in a state in which water is used as ably from 2 to 11, more preferably from 2 to 7, still more a medium in the polishing liquid composition 1-1. The preferably from 2 to 6, especially preferably 3 to 5, from the amount of the organic acid formulated in the polishing liquid viewpoints of keeping a polishing speed at a practical level. composition 1-1 can be widely selected for the purposes of Suppressing the dishing, and removing fine Scratch damages 30 securing the polishing speed at a practical level to remove the on the surface. In order to adjust the pH within the above metal layer, and preventing excessive etching of the metal ranges, an inorganic acid such as nitric acid or Sulfuric acid, layer. The amount of the organic acid formulated is, for an organic acid, a basic Substance Such as potassium hydrox instance, preferably from 0.1 to 10% by weight, more pref ide, Sodium hydroxide, ammonia, or an organic amine can be erably from 0.2 to 8% by weight, still more preferably from appropriately added, as occasion demands. 35 0.3 to 5% by weight. In addition, the polishing liquid composition 1-1 of this In addition, among the above organic acids, a compound embodiment may further comprise an organic acid. capable of dissolving and etching a metal, especially copper In this embodiment, since the organic acid is used, the in the copresence of an aqueous medium, and having an organic acid forms a complex with orbinds to various metals, etching speed “a” of 3 A/min or more, as obtained by the especially copper, constituting the metal layer, so that the 40 following etching test A can be used as an etching agent. metal layer is made brittle, whereby exhibiting an effect that Specifically, in the etching test A, first a copper ribbon (com the removal of the metal layer is made easy during polishing. mercially available from K. K. Nirako; thickness: 0.10 mm. In addition, especially, the organic acid can be used in width: 6 mm) having a length of 100 mm is furnished, and the combination with a compound having a structure in which surface dirt or the like is wiped of with a sheet of paper. each of two or more adjacent carbon atoms has a hydroxyl 45 Thereafter, the copper ribbon is subjected to ultrasonic clean group in a molecule, whereby maintaining the polishing ing for one minute in a state of being immersed in normal speed and preventing the dishing. hexane, and thereafter the Surface is Sufficiently degreased The organic acid is an organic compound showing acidic and dried. Subsequently, its metal test piece is coiled into a property. helical form so that an entire surface of the ribbon is These organic compounds showing acidic property include 50 immersed in the polishing liquid, to give a metal test piece those having functional groups such as carboxyl group, phos before test. The weight before immersion is determined by phonic group, phosphinic group, Sulfonic group, Sulfinic accurate balance. group, phenol group, enol group, thiophenol group, imido Next, the etching agent is diluted to give a 2% by weight group, oxime group, aromatic sulfamide groups, and primary aqueous solution thereof. Further, 100 g of the etching solu and secondary nitro groups. 55 tion of which pH is adjusted to 8+0.5 with aqueous ammonia The organic acid usable in this embodiment has a molecu is furnished in a 150 cc beaker (K.K. Teraoka, 150 cc dispos lar weight of preferably 1000 or less, more preferably 500 or able cup), and the above metal test piece is immersed at 25°C. less. for 12 hours. During immersion, the etching solution is stirred The organic acid having carboxyl group includes mono with a magnetic stirrer, to an extent that the copper ribbon carboxylic acids having 1 to 24 carbon atoms, dicarboxylic 60 rotates along with the flow of the etching solution. After the acids, hydroxycarboxylic acids and aminocarboxylic acids test, the copper ribbon surface is sufficiently wiped off, and its are preferable, from the viewpoint of the solubility in water. weight is again determined by accurate balance, to give a The number of carbon atoms is more preferably 1 to 18 weight after the test. The amount of reduced thickness of carbon atoms, still more preferably 1 to 12 carbon atoms, copper is calculated from the weight loss of the copper ribbon especially preferably 1 to 8 carbon atoms, most preferably 1 65 before and after the test, and the resulting amount is divided to 6 carbonatoms. Concrete examples thereof include mono by the etching time period to determine an etching speed 'a. carboxylic acids, such as formic acid, acetic acid, propionic From the viewpoint of obtaining a practical polishing speed, US 7,604,751 B2 7 8 an etching agent having an etching speed'a' obtainable from to the group E. More preferable are oxalic acid, Succinic acid, the above etching test of 3 A/min or more is preferable, more glycolic acid, lactic acid, citric acid, malic acid, gluconic preferably 5 A/minor more, still more preferably 10 A/minor acid, phthalic acid, aminotri (methylenephosphonic acid), more. The etching speed 'a' in this case may be an etching 1-hydroxyethylidene-1-diphosphonic acid, ethylenedi speed of two or more etching agents used in combination. aminetetraacetic acid, hydrochloric acid, and Sulfuric acid. In addition, as the etching agent, an inorganic acid which is These etching agents may be used alone or in admixture of capable of dissolving and etching a metal, especially copper, two or more kinds. In this embodiment, glycolic acid and in the copresence of an aqueous medium, and having an gluconic acid are especially preferable. etching speed “a” obtainable from the above etching test A of These etching agents, for instance, have the following etch 3 A/min or more can be used. 10 ing speed “a”: Glycolic acid, 60 A/min: citric acid, 25 A/min: Among the organic acids, from the viewpoint of having an phthalic acid, 50 A/min: aminotricmethylenephosphonic appropriate etching speed, preferable etching agents include acid), 10 A/min: ethylenediaminetetraacetic acid, 30 A/min: one or more compounds selected from the group consisting of acetic acid, 70 A/min, glycine, 40A/min: hydrochloric acid, the following Ato D. Also, the following inorganic acids E are 400 A/min; and sulfuric acid, 100 A/min. usable as an etching agent. 15 When the etching agent usable in this embodiment is used A: aliphatic organic acids having 6 or less carbon atoms and in the preparation of a polishing liquid composition, with one to three carboxyl groups; proviso that the composition does not comprise the hydroxyl B: aromatic organic acids having 7 to 10 carbon atoms and group-containing compound, in which an oxidizing agent, one to four carboxyl groups; abrasive grains, and the like are further copresent, it is pref C: organic acids having 6 or less carbonatoms and one to four erable to adjust the kinds, contents, and the like, so that the phosphonic groups; etching liquid composition has an etching speed “b’ obtain D: polyaminocarboxylic acids having in a molecule two or able from the following etching test B of 20 A/min or more. more structures represented by the formula (III): The etching test B is carried out in the same procedures as in the etching test A, except that the copper ribbon is immersed 25 in a polishing liquid composition comprising, as an etching (III) Solution of the etching test A, water, an abrasive and an etching agent, and, if necessary, an oxidizing agent, at room -N-CHCOOH temperature (25°C.) for 2 hours, and that the pH is adjusted to 4.0+0.5. The etching speed obtained by the etching test Bis 30 referred to as “etching speed b. From the viewpoint of and obtaining a practical polishing speed, the etching speed “b' E: inorganic acids. obtainable from the above etching test B is preferably 20 Concretely, the aliphatic organic acid of the group Ahaving A/min or more, more preferably 30 A/minor more, still more 6 or less carbon atoms and one to three carboxyl groups preferably 50 A/min or more. The etching speed "b" in this includes monocarboxylic acids, Such as formic acid, acetic 35 case may be an etching speed of a polishing liquid composi acid, and propionic acid; polycarboxylic acids, Such as oxalic tion in which two or more etching agents are used in combi acid, malonic acid, Succinic acid, glutaric acid, adipic acid, nation. and tricarballylic acid; hydroxycarboxylic acids Such as gly In this embodiment, since the etching agent is used, the colic acid, lactic acid, 2-hydroxypropionic acid, malic acid, etching agent forms a complex with or binds to various met tartaric acid, citric acid, and gluconic acid; amino acids Such 40 als, especially copper, constituting the metal layer, so that the as glycine, alanine, and aspartic acid; and the like. The aro removal of the metals is made easy as water-soluble salts matic organic acid of the group B having 7 to 10 carbonatoms and/or chelated compounds, whereby exhibiting an effect that and one to four carboxyl groups includes benzoic acid, the polishing speed of the metal layer is increased during phthalic acid, trimellitic acid, pyromellitic acid, mandelic polishing. acid, salicylic acid, and the like. The organic acid of the group 45 The amount of the etching agent formulated in the polish C having 6 or less carbon atoms and one to four phosphonic ing liquid composition 1-1 can be variously selected in order groups includes phosphonic acids Such as methylphosphonic to secure the polishing speed at a practical level to remove the acid and phenylphosphonic acid; phosphinic acids such as metal layer, and to prevent excessive etching of the metal methylphosphinic acid and phenylphosphinic acid; phospho layer. The amount of the etching agent formulated is prefer nic acid esters such as methyl ester of phosphonic acid; ami 50 ably from 0.1 to 10% by weight, more preferably from 0.2 to nophosphonic acids such as aminotri (methylenephosphonic 8% by weight, still more preferably from 0.3 to 5% by weight, acid) and 1-hydroxyethylidene-1-diphosphonic acid; and the of the polishing liquid composition 1-1. like. The polyaminocarboxylic acid of the group D having in a molecule two or more structures represented by the formula EMBODIMENT 2 (III) includes ethylenediaminetetraacetic acid, nitrilotriacetic 55 acid, diethylenediaminepentaacetic acid, triethylenetetra In this embodiment, one of the largest features resides in minehexaacetic acid, hydroxyethylethylenediamine that the above aliphatic carboxylic acid having 7 to 24 carbon tetraacetic acid, and the like. The inorganic acid of the group atoms and/or a salt thereof and the etching agent are used in E includes hydrochloric acid, perchloric acid, Sulfuric acid, combination. Since the aliphatic carboxylic acid having 7 to nitric acid, phosphoric acid, phosphonic acid, phosphinic 60 24 carbon atoms and/or a salt thereof has an action of lower acid, and the like. Among them, from the viewpoint of the ing the etching speed, the polishing speed at a practical level polishing speed, preferable are the polycarboxylic acids or can be maintained and excessive etching of the metal film in hydroxycarboxylic acids belonging to the group A or B; ami the metal layer can be prevented by the use of a polishing nophosphonic acids belonging to the group C; polyaminocar liquid composition comprising these compounds and the boxylic acids of the group D having in a molecule two or more 65 etching agent. Therefore, there is exhibited an excellent effect structures represented by the formula (III); and hydrochloric that the polishing Surface without defects Such as dishing can acid, Sulfuric acid, nitric acid, and phosphoric acid belonging be obtained. US 7,604,751 B2 10 From the viewpoints of maintaining the polishing speed When the etching agent usable in this embodiment is used and Suppressing the dishing, the aliphatic carboxylic acid in the preparation of a polishing liquid composition, with and/or a salt thereof has 7 to 24 carbon atoms. Further, from proviso that the composition does not comprise the aliphatic the viewpoints of keeping the solubility in the polishing liq carboxylic acid having 7 to 24 carbon atoms and/or a salt uid, the low-foamability, and the polishing speed at practical thereof, in which an oxidizing agent, abrasive grains, and the levels, and Suppressing the dishing, these compounds have like are further copresent, it is preferable to adjust the kinds, preferably from 7 to 20 carbon atoms, more preferably from contents, and the like, so that the polishing liquid composition 7 to 16 carbon atoms, still more preferably from 7 to 12 has an etching speed 'c' obtainable from the following etch carbon atoms, especially preferably from 7 to 10 carbon ing test Cof 20 A/min or more. The etching test C is carried atOmS. 10 out in the same procedures as in the etching test A, except that In addition, the hydrocarbon group of the aliphatic car the copper ribbon is immersed in a polishing liquid compo boxylic acid and/or a salt thereof may be saturated or unsat sition comprising, as an etching Solution of the etching test A, urated, or linear or branched. water, an abrasive and an etching agent, and, if necessary, an In addition, the salts of the aliphatic carboxylic acids may oxidizing agent, at room temperature (25°C.) for 2 hours. The be any of ammonium salts, salts of organic amines, and alkali 15 etching speed obtained by the etching test C is referred to as metal salts. From the viewpoint of preventing staining of the “etching speed c'. From the viewpoint of obtaining a prac semiconductors, ammonium salts, and salts of organic tical polishing speed, the etching speed 'c' obtainable from amines Such as salts of monoethanolamine, salts of diethano the above etching test C is preferably 20 A/minor more, more lamine, salts of triethanolamine, and salts of triethylamine. preferably 30 A/min or more, still more preferably 50 A/min Concrete examples of these aliphatic carboxylic acids and or more. The etching speed 'c' in this case may be an etching salts thereof include linear, saturated aliphatic carboxylic speed of a polishing liquid composition in which two or more acids such as heptanoic acid, octanoic acid, nonanoic acid, etching agents are used in combination. decanoic acid, lauric acid, myristic acid, palmitic acid, Stearic In this embodiment, since the etching agent is used, the acid, and eicosanoic acid; linear, unsaturated aliphatic car etching agent forms a complex with or binds to various met boxylic acids such as heptenoic acid, octenoic acid, decenoic 25 als, especially copper, constituting the metal layer, so that the acid, dodecenoic, and oleic acid; branched, Saturated ali removal of the metals is made easy as water-soluble salts phatic carboxylic acids such as 2-methylhexanoic acid, 2-eth and/or chelated compounds, whereby exhibiting an effect that ylhexanoic acid,3,5-dimethylhexanoic acid, 3.5.5-trimethyl the polishing speed of the metal layer is increased during hexanoic acid, and isodecanoic acid; and ammonium salts, polishing. salts of organic amines, alkali metal salts of these aliphatic 30 The amount of the etching agent formulated in the polish carboxylic acids, and the like. Among them, from the view ing liquid composition 1-2 can be variously selected in order points of the polishing speed and the suppression of the dish to secure the polishing speed at a practical level to remove the ing, the linear or branched, Saturated aliphatic carboxylic metal layer, and to prevent excessive etching of the metal acids and ammonium salts thereof are preferable, and from layer. The amount of the etching agent formulated is prefer the viewpoint of the solubility in the polishing liquid and the 35 ably from 0.1 to 10% by weight, more preferably from 0.2 to low foamability, heptanoic acid or ammonium salt thereof, 8% by weight, still more preferably from 0.3 to 5% by weight, octanoic acid or ammonium salt thereof, nonanoic acid or of the polishing liquid composition 1-2. ammonium salt thereof, and decanoic acid or ammonium salt Water usable in this embodiment is used as a medium. The thereof are especially preferable. These aliphatic carboxylic amount of water formulated is preferably from 60 to 99.89% acids having 7 to 24 carbon atoms and salts thereof may be 40 by weight, more preferably from 70 to 99.4% by weight, still used alone or in admixture of two or more kinds. more preferably from 80 to 99% by weight, of the polishing The amount of the aliphatic carboxylic acid and a salt liquid composition 1-2, from the viewpoint of efficiently thereof formulated is preferably from 0.01 to 30% by weight, polishing the substrate to be polished. more preferably from 0.02 to 10% by weight, still more The polishing liquid composition 1-2 of this embodiment preferably from 0.03 to 5% by weight, of the polishing liquid 45 having the composition described above has a pH of prefer composition 1-2, from the viewpoint of maintaining the pol ably 10 or less, more preferably from 2 to 9.5, still more ishing speed, and Suppressing the dishing. preferably from 4 to 9, especially preferably from 7 to 9, from The etching agent usable in this embodiment is capable of the viewpoints of keeping a polishing speed at a practical dissolving and etching a metal, especially copper, in the level, Suppressing the dishing, and removing fine Scratch copresence of an aqueous medium, and is a compound having 50 damages on the Surface. In order to adjust the pH within the an etching speed “a”) of 3 A/min or more, as obtained by the above ranges, an inorganic acid such as nitric acid or Sulfuric etching test A described in Embodiment 1. From the view acid, an organic acid; a basic Substance Such as potassium point of obtaining a practical polishing speed, an etching hydroxide, Sodium hydroxide, ammonia, oran organic amine agent having an etching speed 'a' obtainable from the above can be appropriately added, as occasion demands. etching test A of 3 A/min or more is preferable, more prefer 55 ably 5 A/minor more, still more preferably 10 A/minor more. EMBODIMENT 3 The etching speed 'a' in this case may be an etching speed of two or more etching agents used in combination. In this embodiment, one of the largest features resides in Preferable etching agents include the same ones as those in that the above amine compound represented by the general Embodiment 1 mentioned above. These etching agents may 60 formula (II) and/or a salt thereof and the etching agent are be used alone or in admixture of two or more kinds. In this used in combination. The polishing speed at a practical level embodiment, glycolic acid, citric acid, and aminotri (methyl can be maintained and excessive etching of the metal film of enephosphonic acid) are especially preferable. Incidentally, the metal layer can be prevented by the use of a polishing the etching speed “a” of the aliphatic carboxylic acid having liquid composition comprising the amine compound and/or a 7 to 24 carbon atoms is 2 A/min or less, and as compared to 65 salt thereof, and the etching agent. Therefore, there is exhib the etching agent, the etching strength is none or almost not ited an excellent effect that the polishing surface without found. defects such as dishing can be obtained. US 7,604,751 B2 11 12 The above amine compound represented by the general embodiment, glycolic acid, citric acid, and aminotri (methyl formula (II) and/or a salt thereofusable in this embodiment is enephosphonic acid) are especially preferable. preferable, from the viewpoints of maintaining the polishing When the etching agent usable in this embodiment is used speed and Suppressing the dishing. Further, from the view in the preparation of a polishing liquid composition, with points of keeping the low foam ability and the polishing speed proviso that the composition does not comprise the above at practical levels and Suppressing the dishing, in the formula, amine compound or a salt thereof, in which an oxidizing R is preferably a linear or branched, alkyl or alkenyl group agent, abrasive grains, and the like are further copresent, it is having 5 to 14 carbon atoms, more preferably a linear or preferable to adjust the kinds, contents, and the like, so that branched, alkyl or alkenyl group having 6 to 12 carbonatoms, the polishing liquid composition has an etching speed 'c' still more preferably a linear or branched, alkyl or alkenyl 10 obtainable from the etching test C described in Embodiment group having 7 to 10 carbon atoms. Each of R and R is 2 of 20 A/min or more. From the viewpoint of obtaining a preferably hydrogen, a linear alkyl group having 1 or 2 carbon practical polishing speed, the etching speed 'c' obtainable atoms, agroup represented by H. (OR) , wherein Risan from the above etching test C is preferably 20 A/min or more, alkylenegroup having 2 carbonatoms and Z is a number from more preferably 30 A/min or more, still more preferably 50 1 to 4, and more preferably hydrogenatom, methyl group and 15 A/min or more. The etching speed “c” in this case may be an hydroxyethyl group. etching speed of a polishing liquid composition in which two In addition, the salt of the amine compound may be either or more etching agents are used in combination. a salt with an inorganic acid or a salt with an organic acid, and In this embodiment, since the etching agent is used, the those which are a salt with an inorganic acid or organic acid etching agent forms a complex with or binds to various met which is usable as an etching agent are preferable. Further, als, especially copper, constituting the metal layer, so that the from the viewpoint of preventing staining of the semiconduc removal of the metals is made easy as water-soluble salts tor, salts of organic acids are more preferable among the and/or chelated compounds, whereby exhibiting an effect that etching agents. the polishing speed of the metal layer is increased during Concrete examples of these amine compounds and salts polishing. thereof include linear monoalkylamines such as butylamine, 25 The amount of the etching agent formulated in the polish pentylamine, hexylamine, heptylamine, octylamine, nony ing liquid composition 1-3 can be variously selected in order lamine, decylamine, laurylamine, myristylamine, and Steary to secure the polishing speed at a practical level to remove the lamine; linear monoalkenylamines Such as oleylamine; metal layer, and to prevent excessive etching of the metal branched monoalkylamines Such as 2-ethylhexylamine; layer. The amount of the etching agent formulated is prefer dialkylamines Such as dihexylamine and dioctylamine; tri 30 ably from 0.1 to 10% by weight, more preferably from 0.2 to alkylamines Such as dimethyloctylamine, dimethyldecy 8% by weight, still more preferably from 0.3 to 5% by weight, lamine, and dimethyldodecylamine; alkylalkanolamines of the polishing liquid composition 1-3. Such as octyldiethanolamine, decyldiethanolamine, and Water usable in this embodiment is used as a medium. The dodecyldiethanolamine; and carboxylates, phosphates, amount thereof is preferably from 60 to 99.89% by weight, hydrochlorides, sulfates, nitrates, and the like of these amine 35 more preferably from 70 to 99.4% by weight, still more compounds. Among them, from the viewpoints of maintain preferably from 80 to 99% by weight, of the polishing liquid ing the polishing speed and Suppressing the dishing, composition 1-3, from the viewpoint of efficiently polishing monoalkylamines, monoalkyldimethylamines, and the substrate to be polished. monoalkyldiethanolamines, each of which is linear or The polishing liquid composition 1-3 of this embodiment branched, and carboxylates thereof are preferable. Further, 40 having the composition described above has a pH of prefer from the viewpoint of the low foamability, more preferable ably 10 or less, more preferably from 2 to 9.5, still more are heptylamine, octylamine, nonylamine, dimethylocty preferably from 4 to 9, especially preferably from 5 to 9, from lamine, dimethyldecylamine, dimethyldodecylamine the viewpoints of keeping a polishing speed at a practical octyldiethanolamine, decyldiethanolamine, and carboxylates level, Suppressing the dishing, and removing fine Scratch thereof. These amine compounds and salts thereof may be 45 damages on the Surface. In order to adjust the pH within the used alone or in admixture of two or more kinds. above ranges, an inorganic acid such as nitric acid or Sulfuric acid, an organic acid, a basic Substance such as potassium The amount of the amine compound and a salt thereof hydroxide, Sodium hydroxide, ammonia, oran organic amine formulated is preferably from 0.01 to 30% by weight, more can be appropriately added, as occasion demands. preferably from 0.02 to 10% by weight, still more preferably 50 The polishing liquid composition 2 comprises one of the from 0.03 to 5% by weight, of the polishing liquid composi polishing liquid compositions 1-1 to 1-3 (hereinafter collec tion 1-3, from the viewpoint of maintaining the polishing tively referred to as “the polishing liquid composition 1), and speed, and Suppressing the dishing. further comprising an oxidizing agent. The oxidizing agent The etching agent usable in this embodiment is capable of usable in the present invention refers to those oxidizing a dissolving and etching a metal, especially copper, in the 55 metal. In the present invention, it is thought that the metal copresence of an aqueous medium, and is a compound having layer is oxidized by the use of the oxidizing agent, whereby an an etching speed “a” of 3 A/min or more, as obtained by the effect of accelerating the mechanical polishing effect of the etching test A described in Embodiment 1. From the view metal layer is exhibited. point of obtaining a practical polishing speed, an etching The oxidizing agent includes, peroxides; permanganic acid agent having an etching speed 'a' obtainable from the above 60 or salts thereof, chromic acid or salts thereof, nitric acid or etching test A of 3 A/min or more is preferable, more prefer salts thereof; peroxo acid or salts thereof oxyacid or salts ably 5 A/minor more, still more preferably 10 A/minor more. thereof metal salts; sulfuric acid, and the like. The etching speed 'a' in this case may be an etching speed of As concrete examples thereof, the peroxide includes two or more etching agents used in combination. hydrogen peroxide, Sodium peroxide, barium peroxide, and Preferable etching agents include the same ones as those in 65 the like; the permanganic acid or salts thereof include potas Embodiment 1 mentioned above. These etching agents may sium permanganate, and the like; chromic acid or salts thereof be used alone or in admixture of two or more kinds. In this include metal salts of chromic acid, metal salts of dichromic US 7,604,751 B2 13 14 acid, and the like; the nitrates include iron(III) nitrate, ammo tical level, Suppressing the dishing, and removing the fine nium nitrate, and the like; the peroxo acid or salts thereof scratch damages on the Surface. include peroxodisulfuric acid, ammonium peroxodisulfate, In addition, when the polishing liquid composition 2 is metal salts of peroxodisulfuric acid, peroxophosphoric acid, prepared from the polishing liquid composition 1-3, the peroxoSulfuric acid, Sodium peroxoborate, performic acid, amount of the amine compound and/or salts thereof formu peracetic acid, perbenzoic acid, perphthalic acid, and the like; lated is preferably from 0.01 to 30% by weight, more prefer the oxyacid or salts thereof include hypochlorous acid, hypo ably from 0.02 to o% by weight, still more preferably from bromous acid, hypoiodous acid, chloric acid, bromic acid, 0.03 to 5% by weight, of the polishing liquid composition 2. iodic acid, perchloric acid, Sodium hypochlorite, calcium The amount of the etching agent formulated is preferably hypochlorite, and the like: metal salts include iron (III) chlo 10 from 0.1 to 10% by weight, more preferably from 0.2 to 8% ride, iron (III) sulfate, iron (III) citrate, ammonium iron (III) by weight, still more preferably from 0.3 to 5% by weight, of Sulfate, and the like. Among the oxidizing agents, hydrogen the polishing liquid composition 2. The amount of water peroxide, iron (III) nitrate, peracetic acid, ammonium per formulated is preferably from 39.89 to 99.79% by weight, oxodisulfate, iron (III) sulfate and ammonium iron (III) sul more preferably from 70 to 99.4% by weight, still more fate are preferable, and especially hydrogen peroxide is pref 15 preferably from 80 to 99% by weight, of the polishing liquid erable. These oxidizing agents may be used alone or in composition 2. The pH of the polishing liquid composition 2 admixture of two or more kinds. having the above composition, which is the same as the pol The oxidizing agent is used in a state in which water is used ishing liquid composition 1-3, is preferably 10 or less, more as a medium in the polishing liquid composition 2. The preferably from 2 to 9.5, still more preferably 4 to 9, espe amount of the oxidizing agent formulated is preferably from cially preferably from 5 to 9, from the viewpoints of keeping 0.1 to 60% by weight, more preferably from 0.2 to 50% by the polishing speed at a practical level, Suppressing the dish weight, still more preferably from 0.3 to 30% by weight, ing, and removing the fine Scratch damages on the Surface. especially preferably from 0.3 to 10% by weight, of the pol The polishing liquid compositions 1 and 2 of the present ishing liquid composition 2, from the viewpoint of obtaining invention are effective for polishing processes using a fixed the polishing speed at a practical level by rapid oxidation of 25 grinding wheel, a polishing pad in which abrasive grains are the metal layer. fixed to the pad, and the like. For instance, by the use of the In addition, when the polishing liquid composition 2 is polishing liquid compositions 1 and 2 of the present invention prepared from the polishing liquid composition 1-1, the during polishing in the polishing process using the fixed grinding wheel, the polishing speed can be maintained, and amount of the hydroxyl group-containing compound formu 30 lated is preferably from 0.01 to 30% by weight, more prefer the dishing of the metal layer can be Suppressed. ably from 0.05 to 5% by weight, still more preferably from The polishing liquid composition 3 of the present invention 0.1 to 3% by weight, of the polishing liquid composition 2. is one further comprising an abrasive to a polishing liquid The amount of water formulated is preferably from 40 to composition 1 or 2, which is usable for a polishing process by 99.89% by weight, more preferably from 70 to 99.4% by 35 loose abrasives. weight, still more preferably from 80 to 99% by weight, of the As the abrasive, abrasives generally employed for polish polishing liquid composition 2. The pH of the polishing liquid ing can be used. The abrasive includes, for instance, metals, composition 2 having the above composition, which is the carbides of metals or metalloids, nitrides of metals or metal same as the polishing liquid composition 1-1, is preferably loids, oxides of metals or metalloids, borides of metals or from 2 to 11, more preferably from 2 to 7, still more prefer 40 metalloids, diamond, and the like. The metals or metalloids ably 2 to 6, especially preferably from 3 to 5, from the view include those elements belonging to the Groups 3A, 4A, 5A, points of keeping the polishing speed at a practical level. 3B, 4B, 5B, 6B, 7B or 8B of the Periodic Table. Examples Suppressing the dishing, and removing the fine Scratch dam thereof include silicon dioxide, aluminum oxide, cerium ages on the Surface. In order to adjust the pH to the above oxide, titanium oxide, Zirconium oxide, silicon nitride, man specified range, there may be added at an appropriate timing 45 ganese dioxide, silicon carbide, Zinc oxide, diamond, and an inorganic acid such as nitric acid or Sulfuric acid, an magnesium oxide. Among them, silicon dioxide, aluminum organic acid, or a basic Substance Such as potassium hydrox oxide and cerium oxide are preferable. As concrete examples ide, Sodium hydroxide, ammonia, or an organic amine. thereof, the silicon dioxide includes colloidal silica particles, In addition, when the polishing liquid composition 2 is fumed silica particles, Surface-modified silica particles, and prepared from the polishing liquid composition 1-2, the 50 the like; the aluminum oxide includes C-alumina particles, amount of the aliphatic carboxylic acid having 7 to 24 carbon Y-alumina particles, Ö-alumina particles, 0-alumina particles, atoms and/or salts thereof formulated is preferably from 0.01 m-alumina particles, amorphous alumina particles, and other to 30% by weight, more preferably from 0.02 to 10% by fumed alumina or colloidal alumina prepared by different weight, still more preferably from 0.03 to 5% by weight, of process; the cerium oxide includes ones having oxidation the polishing liquid composition 2. The amount of the etching 55 state of 3 or 4, of which crystal system is hexagonal system, agent formulated is preferably from 0.1 to 10% by weight, isometric system, or face-centered cubic system, and the like. more preferably from 0.2 to 8% by weight, still more prefer The silicon dioxide is especially preferable. These abrasives ably from 0.3 to 5% by weight, of the polishing liquid com may be used alone or in admixture of two or more kinds. position 2. The amount of water formulated is preferably The abrasive has a primary average particle size of prefer from 39.89 to 99.79% by weight, more preferably from 70 to 60 ably from 5 to 1000 nm, more preferably from 10 to 500 nm, 99.4% by weight, still more preferably from 80 to 99% by still more preferably from 20 to 300 nm, especially preferably weight, of the polishing liquid composition 2. The pH of the from 50 to 200 nm, most preferably from 50 to 100 nm. The polishing liquid composition 2 having the above composi lower limit of the average particle size is preferably 5 nm or tion, which is the same as the polishing liquid composition more, from the viewpoint of maintaining a given polishing 1-2, is preferably 10 or less, more preferably from 2 to 9.5, 65 speed, and the upper limit thereof is preferably 1000 nm or still more preferably 4 to 9, especially preferably from 7 to 9, less, form the viewpoint of preventing the generation of from the viewpoints of keeping the polishing speed at a prac scratches on the surface of the substrate to be polished. US 7,604,751 B2 15 16 Especially when the silicon dioxide is used as an abrasive, viewpoints of keeping the polishing speed at a practical level. the silicon dioxide has a primary average particle size of 5 nm Suppressing the dishing, and removing the fine Scratch dam or more, preferably 10 nm or more, more preferably 20 nm or ages on the Surface. more, from the viewpoint of improving the polishing speed. In addition, when the polishing liquid composition 3 is Incidentally, the primary average particle size of the abra prepared from the polishing liquid composition 1-2 (herein sive is determined by adding 0.1 g of the abrasive to 100 g of after referred to as “polishing liquid composition 3-2), the a 0.1% aqueous solution of Sodium polystyrenesulfonate, amount of the aliphatic carboxylic acid having 7 to 24 carbon thereafter applying ultrasonic waves, to disperse the abrasive, atoms and/or salts thereof formulated is preferably from 0.01 and measuring image analysis of the dispersion by observing to 30% by weight, more preferably from 0.02 to 10% by with a transmission electron microscope. 10 weight, still more preferably from 0.03 to 5% by weight, of When the polishing liquid composition 3 is used when the polishing liquid composition 3-2, from the viewpoints of forming interconnection of a semiconductor device, espe maintaining the polishing speed and Suppressing the dishing. cially preferably usable abrasives are silica particles having The amount of the etching agent formulated in the polish purity of preferably 98% by weight or more, more preferably ing liquid composition 3-2 can be variously selected in order 99% by weight or more, especially preferably 99.9% by 15 to secure a polishing speed at a practical level for removal of weight or more. The abrasive includes fumed silica prepared the metal layer, and to prevent excessive etching of the metal by Subjecting a Volatile silicon compound Such as silicon layer. The amountformulated is, for instance, preferably from tetrachloride to high-temperature hydrolysis in oxyhydrogen 0.1 to 10% by weight, more preferably from 0.2 to 8% by flame; or colloidal silica obtained by a process in which an weight, still more preferably from 0.3 to 5% by weight, of the alkali silicate or ethyl silicate is used as a starting material. polishing liquid composition 3-2. Incidentally, the purity of the above abrasive is obtained as The amount of the oxidizing agent formulated is preferably follows. Specifically, the purity can be determined by dissolv from 0.1 to 60% by weight, more preferably from 0.2 to 50% ing 1 to 3g of an abrasive in an acid oran aqueous alkali, and by weight, still more preferably from 0.3 to 30% by weight, quantifying silicon ions by ICP (plasma emission analysis). especially preferably from 0.3 to 10% by weight, of the pol The abrasive is used in a so-called “slurry state' using 25 ishing liquid composition 3-2, from the viewpoint of obtain water as a medium in the polishing liquid composition 3. The ing a polishing speed at a practical level by rapid oxidation of amount of the abrasive formulated in the polishing liquid the metal layer. composition 3 can be variously selected depending upon the The amount of water formulated is preferably from 39.88 Viscosity of the polishing liquid composition and the required to 99.88% by weight, more preferably from 60 to 99.4% by quality of the substrate to be polished, and the like. The 30 weight, still more preferably from 75 to 99% by weight, of the amount of the abrasive formulated is preferably from 0.01 to polishing liquid composition 3-2. The pH of the polishing 30% by weight, more preferably from 0.02 to 20% by weight, liquid composition 3-2 having the above composition, which still more preferably from 0.1 to 20% by weight, especially is the same as the polishing liquid composition 1-2, is pref preferably from 1.0 to 10% by weight, of the polishing liquid erably 10 or less, more preferably from 2 to 9.5, still more composition 3. 35 preferably from 4 to 9, especially preferably from 7 to 9, from In addition, when the polishing liquid composition 3 is the viewpoints of keeping the polishing speed at a practical prepared from the polishing liquid composition 1-1 (herein level, Suppressing the dishing, and removing the fine Scratch after referred to as “polishing liquid composition 3-1), the damages on the Surface. In order to adjust the pH within the amount of the hydroxyl-group containing compound formu above ranges, an inorganic acid such as nitric acid or Sulfuric lated is preferably from 0.01 to 30% by weight, more prefer 40 acid, an organic acid, a basic Substance such as potassium ably from 0.05 to 5% by weight, still more preferably from hydroxide, Sodium hydroxide, ammonia, oran organic amine 0.1 to 3% by weight, of the polishing liquid composition 3-1, can be appropriately added, as occasion demands. from the viewpoints of maintaining the polishing speed and In addition, when the polishing liquid composition 3 is Suppressing the dishing. 45 prepared from the polishing liquid composition 1-3 (herein The amount of the organic acid formulated in the polishing after referred to as “polishing liquid composition 3-3), the liquid composition 3-1 can be variously selected in order to amount of the amine compound and/or salts thereof formu secure a polishing speed at a practical level for removal of the lated is preferably from 0.01 to 30% by weight, more prefer metal layer, and to prevent excessive etching of the metal ably from 0.02 to 10% by weight, still more preferably from layer. The amount is, for instance, preferably from 0.1 to 10% 0.03 to 5% by weight, of the polishing liquid composition 3-3, by weight, more preferably from 0.2 to 8% by weight, still 50 from the viewpoints of maintaining the polishing speed and more preferably from 0.3 to 5% by weight, of the polishing Suppressing the dishing. liquid composition 3-1. The amount of the etching agent formulated in the polish The amount of the oxidizing agent formulated is preferably ing liquid composition 3-3 can be variously selected in order from 0.1 to 60% by weight, more preferably from 0.2 to 50% 55 to secure a polishing speed at a practical level for removal of by weight, still more preferably from 0.3 to 30% by weight, of the metal layer, and to prevent excessive etching of the metal the polishing liquid composition 3-1, from the viewpoint of layer. The amountformulated is, for instance, preferably from obtaining a polishing speed at a practical level by rapid oxi 0.1 to 10% by weight, more preferably from 0.2 to 8% by dation of the metal layer. weight, still more preferably from 0.3 to 5% by weight, of the The amount of water formulated is preferably from 40 to 60 polishing liquid composition 3-3. 99.98% by weight, more preferably from 60 to 99.4% by The amount of the oxidizing agent formulated is preferably weight, still more preferably from 75 to 99% by weight, of the from 0.1 to 60% by weight, more preferably from 0.2 to 50% polishing liquid composition 3-1. The pH of the polishing by weight, still more preferably from 0.3 to 30% by weight, liquid composition 3-1 having the above composition, which especially preferably from 0.3 to 10% by weight, of the pol is the same as the polishing liquid composition 1-1, is pref 65 ishing liquid composition 3-3, from the viewpoint of obtain erably from 2 to 11, more preferably from 2 to 7, still more ing a polishing speed at a practical level by rapid oxidation of preferably 2 to 6, especially preferably from 3 to 5, from the the metal layer. US 7,604,751 B2 17 18 The amount of water formulated is preferably from 39.88 invention is used in the formation of the metal interconnec to 99.88% by weight, more preferably from 60 to 99.4% by tion layer made of copper or copper alloys, there are exhibited weight, still more preferably from 75 to 99% by weight, of the remarkable effects of maintaining the polishing speed and polishing liquid composition 3-3. The pH of the polishing Suppressing the dishing of the embedded metal interconnec liquid composition 3-3 having the above composition, which tion layer. In addition, the material for forming the insulating is the same as the polishing liquid composition 1-3, is pref layer may be any of organic or inorganic materials, and erably 10 or less, more preferably from 2 to 9.5, still more preferably from 4 to 9, especially preferably from 5 to 9, from includes inorganic materials such as silicon dioxide, fluori the viewpoints of keeping the polishing speed at a practical nated silicon dioxide, hydrogen-containing SOG (spin-on level, Suppressing the dishing, and removing the fine Scratch glass), nitrides, such as tantalum nitride and titanium nitride; damages on the Surface. 10 and organic materials such as organic SOG, polyimides, flu The polishing liquid compositions 1 to 3 of the present orinated polyimides, methyl polysiloxanes, aromatic poly invention can be prepared in any manner without particular ethers, hydrogensilsesquioxane, and fluorocarbons. limitations, and for instance, a polishing liquid composition The shape of these substrates to be polished is preferably can be obtained by appropriately mixing each of the above those having a shape of forming recesses of an interconnec components, and adjusting a pH. Concrete examples thereof 15 tion shape on the insulating film Surface of the semiconductor are as follows. Substrate, and sedimenting metals on the insulating film The polishing liquid composition 1 of the present invention including the recesses. In addition, there may be provided a can be, for instance, prepared by the following procedures. barrier film made of tantalum, titanium, or a nitride thereof First, an organic acid and/or an etching agent is added to a between the insulating film and the metal layer. Especially given amount of water, and a pH is adjusted to a given value. when the metal layer is made of copper or copper alloys, it is To the pH-adjusted aqueous solution of the organic acid and/ preferable to provide the barrier film, whereby the diffusion or etching agent is added a given amount of an aqueous of the copper to the insulating layer can be prevented. Solution of a hydroxyl group-containing compound; or an The polishing liquid compositions 1 and 2 of the present aqueous Solution of an aliphatic carboxylic acid having 7 to invention are effective for a polishing processes using a fixed 24 carbonatoms and/or salts thereof, or an amine compound 25 and/or salts thereof, the aqueous solution of which pH is grinding wheel, a polishing pad in which abrasive grains are adjusted to a given level. A pH is finally adjusted, whereby a fixed to the pad, and the like. The polishing liquid composi polishing liquid composition 1 can be obtained. tion 3 is effective for a polishing process by loose abrasives The polishing liquid composition 2 can be, for instance, using a usual polishing pad made of urethane, and it is also prepared by the following procedures. First, an organic acid effective for a polishing processes using a fixed grinding and/or an etching agent is added to a given amount of water, 30 wheel, a polishing pad in which abrasive grains are fixed to and a pH is adjusted to a given value. To the pH-adjusted the pad, and the like. aqueous solution of the organic acid and/or etching agent is The process for polishing a surface to be polished compris added a given amount of an aqueous solution of a hydroxyl ing an insulating layer and a metal layer of the present inven group-containing compound; or an aqueous Solution of an tion comprises polishing a semiconductor Substrate using the aliphatic carboxylic acid having 7 to 24 carbon atoms and/or 35 polishing liquid composition of the present invention, thereby salts thereof, or an amine compound and/or salts thereof, the Smoothening the polished Surface. aqueous solution of which pH is adjusted to a given level. An oxidizing agent is added before polishing, and a pH is finally In addition, the process for manufacturing a semiconductor adjusted, whereby a polishing liquid composition 2 can be Substrate of the present invention comprises polishing a semi obtained. 40 conductor Surface comprising an insulating layer and a metal The polishing liquid composition 3 can be, for instance, layer using the polishing liquid composition of the present prepared by the following procedures. First, an organic acid invention, whereby the polishing speed of the metal layer can and/or an etching agent is added to a given amount of water, be maintained and the dishing of the embedded metal inter and a pH is adjusted to a given value. To the pH-adjusted connection layer can be suppressed. Therefore, the process aqueous solution of the organic acid and/or etching agent is 45 can be suitably applied to a process for manufacturing the added a given amount of an abrasive, and the mixture is semiconductor Substrate. sufficiently stirred so as to uniformly disperse the abrasives. Further, to the dispersion is added a given amount of an EXAMPLES I-1 TO I-14 AND COMPARATIVE aqueous solution of a hydroxyl group-containing compound; EXAMPLES I-1 TO I-4 or an aqueous solution of an aliphatic carboxylic acid having 50 7 to 24 carbon atoms and/or salts thereof, or an amine com Compounds having a structure in which each of two or pound and/or salts thereof, the aqueous solution of which pH more adjacent carbon atoms has hydroxyl group in a mol is adjusted to a given level. A given amount of an oxidizing ecule (hydroxyl group-containing compound) used in agent is added before polishing as occasion demands, and a Examples I-1 to I-14 are shown in Table 1. The hydroxyl pH is finally adjusted, whereby a polishing liquid composi group-containing compound shown in Table 1, the organic tion 3 can be obtained. 55 acid shown in Table 2, and hydrogen peroxide were mixed so In addition, various polishing aids other than those listed as to have the proportion shown in Table 2. Further, 5% by above Such as Surfactants and dispersion stabilizers may be weight portion of an abrasive shown in Table 2 and balance added to each of the polishing liquid compositions 1 to 3. water were mixed with stirring, and thereafter a pH of the The polishing liquid composition of the present invention liquid mixture was adjusted to 4.0, to give a polishing liquid can be suitably used for the metal CMP in which a surface 60 composition. Incidentally, each of the used abrasives was comprising an insulating layer and a metal layer is Subject to fumed silica (primary particle size: 50 nm) and colloidal polishing. The metal constituting the metal layer includes silica (primary particle size: 30 nm). In addition, each of the copper or copper alloys, aluminum or aluminum alloys, tung hydroxyl group-containing compounds “a” to 'e' of Table 1 Sten, and the like. Among these metals, especially when used dissolves in water at 1.0% by weight or more. The substrate to for a process for forming embedded metal interconnection on 65 be polished was polished under the following conditions by a semiconductor Substrate, copper or copper alloys are pref single-sided polishing machine. Hereinbelow, the terms erable. When the polishing liquid composition of the present inside quotation marks are trade names. US 7,604,751 B2 19 20 Setting Conditions of Single-Sided Processing Machine Comparative Example I-1; each of the relative etching speeds Single-sided processing machine used: single-sided polish for Examples I-6 to I-8 was calculated based on Comparative ing machine (disc size: 30 cm), manufactured by Engis. Example I-2; and each of the relative etching speeds for Processing pressure: 29.4x10 Pa Examples I-13 to I-14 was calculated based on Comparative Polishing Pad: upper layer: “IC1000' (manufactured by 5 Example I-3. Incidentally, apart from the above, the relative etching speed for Examples I-11 was calculated based on Rodel Nitta K.K.); and lower layer: “SUBA400' (manu Comparative Example I-1; the relative etching speed for factured by Rodel Nitta K.K.). Examples I-12 was calculated based on Comparative Disc rotational speed: 60 rpm Example I-2; and the relative etching speed for Comparative Work rotational speed: 50 rpm (rotating disc and work in the Example I-4 was calculated based on Comparative Example same direction) 10 I-1. Incidentally, each the etching speeds for each the polish Feeding flow rate for a polishing liquid composition: 100 ing liquid compositions of Examples I-1 to I-14 and Com ml/min parative Example 1-4 was a value measured under the same Polishing time period: 10 minutes conditions as the above etching test B described above, except In addition, the properties of the polishing liquid compo for using these polishing liquid compositions. sition Such as relative polishing speed, relative etching speed, and dishing of the surface to be polished were evaluated in 15 Dishing accordance with the following methods. The results thereof In order to evaluate dishing, a wafer chip of a square with are shown in Table 2. a side of 20 mm was cut out from a wafer (commercially available from SKW, “SKW6-2, size: 200 mm) with copper Relative Polishing Speed damascene interconnection patterns. Five wafer chips were The relative polishing speed is a value obtained by dividing fixed on an adhesive plate made of ceramic. Thereafter, a the polishing speed of a polishing liquid composition by a copper film in the periphery of the copper interconnection polishing speed of a comparative example where the kinds portion, the interconnection of which had a width of 150 um, and the amounts of an abrasive, an oxidizing agent and an was removed, with confirming the state under the above con etching agent were the same as the polishing liquid compo ditions. The substrate was polished to a point where a barrier sition. The polishing speed was obtained by polishing a rolled film appeared, and was further polished with 20% of a time copper plate of a diameter of 50 mm and a plate thickness of 25 period required for polishing until this point, to provide a 1 mm, determining a change in the thickness before and after sample for evaluating dishing. The dishing was evaluated by polishing, and dividing the resultant value by a polishing determining a cross section profile of a copper interconnec time. Incidentally, the thickness of the copper plate was mea tion portion, the interconnection of which had a width of 150 sured by using a high-precision digital analyzer "MINIAX” um by a Surface roughness tester (commercially available commercially available from K. K. Tokyo Seimitsu. Here, 30 from (K. Mitsutoyo, “SV-600). Incidentally, when there each of the relative polishing speeds for Examples I-1 to I-5 were no recesses having sizes of 0.15um or more in the cross and I-9 to I-10 was calculated based on Comparative Example section profile of the copper interconnection tested, it was I-1; each of the relative polishing speeds for Examples I-6 to evaluated as absence of dishing, and when there were recesses I-8 was calculated based on Comparative Example I-2; and having sizes of 0.15um or more, it was evaluated as presence each of the relative polishing speeds for Examples I-13 to I-14 35 of dishing, which are respectively denoted in Table 2 as was calculated based on Comparative Example I-3. Inciden “absence' or “presence.” tally, apart from the above, the relative polishing speed for Here, the etching speed “b” of the polishing liquid compo Examples I-11 was calculated based on Comparative sitions used for Comparative Examples I-1 to I-3 were as Example I-1; the relative polishing speed for Examples I-12 follows. was calculated based on Comparative Example I-2; and the Comparative Example I-1:80 A/min relative polishing speed for Comparative Example I-4 was 40 Comparative Example I-2:80 A/min calculated based on Comparative Example I-1. Comparative Example I-3:200 A/min Relative Etching Speed The relative etching speed is a value obtained by dividing TABLE 1 an etching speed of the polishing liquid composition com prising the above hydroxyl group-containing compound by 45 Hydroxyl Group-Containing Compound an etching speed 'b' of a polishing liquid composition not containing the above hydroxyl group-containing compound but having the same kinds and the amounts of an abrasive, an oxidizing agent and an etching agent as the polishing liquid composition. Here, each of the relative etching speeds for 50 Examples I-1 to I-5 and I-9 to I-10 was calculated based on

TABLE 2 Hydroxyl Group Containing Compound Organic Acid Hydrogen

Content Content Peroxide (% by (% by Content Abrasive Kind wt.) Kind wt.) (% by wt.) Kind

Ex. No.

I-1 8. 1.O Gluconic 2.0 2.0 Fumed acid Silica I-2 b 1.O Gluconic 2.0 2.0 Fumed acid Silica US 7,604,751 B2 21 22

TABLE 2-continued 1.O Gluconic 2.0 2.0 Fumed 80 i Silica 1.O l conic 2.0 2.0 Fumed i Silica 1.O l conic 2.0 2.0 Fumed i Silica 1.O l conic 2.0 2.0 Colloidal i Silica 1.O luconic 2.0 2.0 Colloidal i Silica 1.O l conic 2.0 2.0 Colloidal i Silica l conic 2.0 2.0 Fumed i Silica -10 2.0 l conic 2.0 2.0 Fumed i Silica -11 1.O 2.0 Fumed Silica -12 1.O l conic 2.0 Colloidal Silica -13 1.O ycolic 2.0 2.0 Colloidal Silica -14 1.O ycolic 2.0 2.0 Colloidal Silica Comp. Ex. No.

Gluconic 2.0 2.0 Fumed acid Silica Gluconic 2.0 2.0 Colloidal acid Silica Glycolic 2.0 2.0 Colloidal acid Silica Benzotriazole 1.O Gluconic 2.0 2.0 Fumed acid Silica Evaluation of Properties

Relative Relative Polishing Speed Etching Speed

Based on Based on Based on Based on Based on Based on C. Ex. I-1 C. Ex. I-2 C.Ex. I-3 C.Ex. I-1 C. Ex. I-2 C. Ex. I-3 Dishing

Ex. No.

1.O 0.1 or Absence less 1.O 0.1 or A. SelC6 less 1.O O.15 SelC6 1.1 O.15 SelC6 1.1 O.2 SelC6 1.O SelC6 less 1.O A. SelC6 less 1.1 O.15 SelC6 1.1 0.1 or A SelC6 less -10 1.O 0.1 or Absence less -11 0.7 0.1 or Absence less -12 0.7 Absence less -13 O.1 Absence or less -14 O.1 Absence or less Comp. Ex. No.

1.O Presence 1.O Presence US 7,604,751 B2 23 24

TABLE 2-continued I-3 1.O Presence I-4 O.1 0.1 or : less

Note * The polishing speed was too slow to be evaluated.

It is found from the results of Tables 1 and 2 that all of the 10 and dividing the resultant value by a polishing time. Inciden polishing liquid compositions of Examples I-1 to I-14 where tally, the thickness of the copperplate was measured by using the hydroxyl group-containing compound is formulated in a high-precision digital analyzer "MINIAX commercially the polishing liquid composition Suppressed the etching available from K. K. Tokyo Seimitsu. Here, each of the rela speed and the dishing is not generated without Substantially tive polishing speeds for Examples II-1 to II-6 was calculated lowering the polishing speed, as compared to the polishing 15 based on Comparative Example II-1; the relative polishing liquid compositions of Comparative Examples I-1 to I-3 speed for Example II-7 was calculated based on Comparative where the hydroxyl group-containing compound is not for Example II-2; the relative polishing speed for Example II-8 mulated. was calculated based on Comparative Example II-3; the rela In addition, it is found that the polishing liquid composition of Comparative Example I-4 where benzotriazole acting to tive polishing speed for Example II-9 was calculated based on Suppressing etching was used in place of the hydroxyl group Comparative Example II-4; the relative polishing speed for containing compound, the polishing speed is extremely low. Example II-10 was calculated based on Comparative Also, it is found that by using the hydroxyl group-contain Example II-5; the relative polishing speed for Example II-11 ing compound, the etching agent, and the oxidizing agent, a was calculated based on Comparative Example II-11; the higher polishing speed can be realized, and the dishing can be 25 relative polishing speed for Example II-12 was calculated prevented. based on Comparative Example II-12; the relative polishing speed for Comparative Example II-9 was calculated based on EXAMPLES II-1 TO II-12 AND COMPARATIVE Comparative Example II-1, and the relative polishing speed EXAMPLES II-1 TO II-12 for Comparative Example II-10 was calculated based on 30 Comparative Example II-2. Incidentally, apart from the Each of the etching agents shown in Tables 3 and 4, and above, each of the relative polishing speeds for Comparative hydrogen peroxide were mixed with a given amount of water, Examples II-6 to II-8 was calculated based on Comparative so as to have the proportion shown in Tables 3 and 4. Further, Example II-1. 5% by weight portion of the abrasive shown in Tables 3 and 4 were mixed with stirring, and thereafter an aqueous ammonia 35 Relative Etching Speed was added so as to have a pH of the liquid mixture of 7.5 to 8. The relative etching speed is a value obtained by dividing Separately from above, an aqueous ammonia was previously an etching speed of the polishing liquid composition com added to an aliphatic carboxylic acid having 7 to 24 carbon prising the above aliphatic carboxylic acid and/or its salt by atoms to adjust the pH to 7.5 to 8, whereby preparing an an etching speed 'c' of a polishing liquid composition not aqueous Solution of the aliphatic carboxylic acid or its salt. 40 containing the above aliphatic carboxylic acid and/or its salt The aqueous solution of the aliphatic carboxylic acid or its but having the same kinds and the amounts of an abrasive, an salt was mixed with the above liquid mixture with stirring, so oxidizing agent and an etching agent as the polishing liquid as to have the proportion shown in Tables 3 and 4. Thereafter, composition. Here, each of the relative etching speeds for a pH of the liquid mixture was adjusted to a value shown in Examples II-1 to II-6 was calculated based on Comparative Tables 3 and 4, to give each polishing liquid composition. 45 Incidentally, each of the used abrasives was fumed silica Example II-1; the relative etching speed for Example II-7 was (primary particle size: 50 nm) and colloidal silica (primary calculated based on Comparative Example II-2; the relative particle size: 100 nm). In addition, a rolled copper plate of a etching speed for Example. II-8 was calculated based on diameter of 50 mm and a plate thickness of 1 mm was pol Comparative Example II-3; the relative etching speed for ished under the same conditions as above by single-sided 50 Example II-9 was calculated based on Comparative Example polishing machine. II-4; the relative etching speed for Example II-10 was calcu In addition, the properties of the polishing liquid compo lated based on Comparative Example II-5; the relative etching sition Such as relative polishing speed, relative etching speed, speed for Example II-11 was calculated based on Compara dishing of the Surface to be polished, and Surface condition of tive Example II-11; the relative etching speed for Example copper were evaluated in accordance with the following 55 II-12 was calculated based on Comparative Example II-12; methods. The results thereof are shown in Tables 3 and 4. the relative etching speed for Comparative Example II-9 was calculated based on Comparative Example II-1; and the rela Relative Polishing Speed tive etching speed for Comparative Example II-10 was cal The relative polishing speed is a value obtained by dividing culated based on Comparative Example II-2. Incidentally, the polishing speed of a polishing liquid composition by a 60 apart from the above, each of the relative etching speeds for polishing speed of a comparative example where the kinds Comparative Examples II-6 to II-8 was calculated based on and the amounts of an abrasive, an oxidizing agent and an Comparative Example II-1. Incidentally, each the etching etching agent were the same as the polishing liquid compo speeds for each the polishing liquid compositions of sition. The polishing speed was obtained by polishing a rolled Examples II-1 to II-12 and Comparative Examples II-7 to II-8 copper plate of a diameter of 50 mm and a plate thickness of 65 was a value measured under the same conditions as the above 1 mm under the polishing conditions mentioned above, deter etching testC described above, except for using these polish mining a change in the thickness before and after polishing, ing liquid compositions. US 7,604,751 B2 25 26 Dishing width of 150 um on the surface of wafer chip used in the Dishing was evaluated in the same manner as above. Inci evaluation of the dishing was observed by optical micro dentally, when there were no recesses having sizes of 0.15um Scope, to confirm the presence or absence of roughening. or more in the cross section profile of the copper interconnec Here, the etching speed 'c' of the polishing liquid compo tion tested, it was evaluated as absence of dishing, and when 5 sitions used for Comparative Examples II-1 to II-6 were as there were recesses having sizes of 0.15 um or more, it was follows. evaluated as presence of dishing, which are respectively Comparative Example II-1:50A/min Comparative Example II-2: 100 A/min denoted in Tables 3 and 4 as “absence' or “presence.” Comparative Example II-3:200 A/min Copper Surface Condition 10 Comparative Example II-4: 600 A/min The surface condition of the copper film at the copper Comparative Example II-5:50 A/min interconnection portion, the interconnection of which has a Comparative Example II-6: 100 A/min

TABLE 3 Aliphatic Carboxylic Acid Hydrogen and or Its Salt Etching Agent Peroxide Abrasive

Kind Content Kind Content Content Kind pH Octanoic 0.6" Glycolic acid 2.0" 4.0' Colloidal 7.6 acid Silica Nonanoic O.3 Glycolic acid 2.0 4.0 Colloidal 7.7 acid Silica Heptanoic 1.2 Glycolic acid 2.0 4.0 Colloidal 7.6 acid Silica Decanoic O.3 Glycolic acid 2.0 4.0 Colloidal 7.7 acid Silica Oleic acid O.3 Glycolic acid 2.0 4.0 Colloidal 8.0 Silica Isooctanoic 1.5 Glycolic acid 2.0 4.0 Colloidal 7.7 acid Silica Octanoic 1.2 Citric acid 2.0 2.0 Fumed 7.6 acid Silica Octanoic 1.0 Phthalic 2.0 2.0 Fumed 7.9 acid acid Silica Octanoic 1.5 Aminotri- 2.0 2.0 Fumed 7.6 acid (methylene- Silica phosphonic acid) -10 Octanoic 0.4 Glycolic acid 2.0 Colloidal 7.6 acid Silica -11 Octanoic 1.0 Hydrochloric 2.0 2.0 Colloidal 7.7 acid acid Silica -12 Octanoic O.S Sulfuric acid 2.0 2.0 Colloidal 7.9 acid Silica Evaluation for Properties

Relative Relative Comp. Ex. To Copper Polishing Etching Which Evaluation Surface Speed Speed Was Based Dishing Condition

1.O 0.1 or less Comp. Ex. II- Absence No Roughening 1.O 0.1 or less Comp. Ex. II- Absence No Roughening 1.O 0.1 or less Comp. Ex. II- Absence No Roughening O.9 0.1 or less Comp. Ex. II- Absence No Roughening O.9 0.1 or less Comp. Ex. II- Absence No Roughening 1.O 0.1 or less Comp. Ex. II- Absence No Roughening 1.O 0.1 or less Comp. Ex. II-2 Absence No Roughening O.9 0.1 or less Comp. Ex. II-3 Absence No Roughening O.9 0.1 or less Comp. Ex. II-4 Absence No Roughening O.9 0.1 or less Comp. Ex. II-5 Absence No Roughening US 7,604,751 B2 27 28

TABLE 3-continued

II-11 O.9 0.1 or less Comp. Ex. II-11 Absence No Roughening II-12 O.9 0.1 or less Comp. Ex. II-12 Absence No Roughening

Note % by weight ‘’Secanoic C8 acid (trade name, commercially available from Exon Chemicals K.K.)

TABLE 4 Aliphatic Comp. Carboxylic Acid Hydrogen Ex. and for Its Salt Etching Agent Peroxide Abrasive

No. Kind Content Kind Content Content Kind pH -1 — Glycolic acid 2.0" 4.0 Colloidal 7.6 Silica -2 — Citric acid 2.0 2.0 Fumed 7.6 Silica -3 — Phthalic 2.0 2.0 Fumed 7.9 acid Silica -4 — Aminotri- 2.0 2.0 Fumed 7.6 (methylene- Silica phosphonic acid) -S — Glycolic acid 2.0 Colloidal 7.6 Silica -6 — Glycolic acid 1.O 4.0 Colloidal 7.6 Citric acid 1.O Silica -7 Octanoic 0.51) 4.0 Colloidal 7.8 acid Silica Heptanoic O.S acid -8 Oleic acid O.S 4.0 Colloidal 7.6 Silica -9 Benzotriazole O.3 Glycolic acid 2.0 4.0 Colloidal 7.6 Silica -10 Ammonium 1.0 Citric acid 2.0 2.0 Fumed 7.6 Polyacrylate Silica -11 — Hydrochloric 2.0 2.0 Colloidal 7.7 acid Silica -12 — Sulfuric 2.0 2.0 Colloidal 7.9 acid Silica Evaluation for Properties Comp. Relative Relative Comp. Ex. To Copper Ex. Polishing Etching Which Evaluation Surface No. Speed Speed Was Based Dishing Condition

-1 O 1.O Presence No Roughening -2 O 1.O Presence No Roughening -3 O 1.O Presence No Roughening -4 O 1.O Presence No Roughening -S O 1.O Presence No. Roughening -6 3 1.5 Comp. Ex. II-1 Presence No Roughening -7 0.1 or less 0.1 or less Comp. Ex. II-1 The polishing speed was -8 0.1 or less 0.1 or less Comp. Ex. II-1 too slow to be evaluated. -9 0.1 or less 0.1 or less Comp. Ex. II-1 -10 .2 0.1 or less Comp. Ex. II-2 Absence Presence of Roughening -11 O 1.O Presence No Roughening -12 O 1.O Presence No Roughening

Note % by weight US 7,604,751 B2 29 30 It is found from the results of Tables 3 and 4 that all of the and the amounts of an abrasive, an oxidizing agent and an polishing liquid compositions of Examples II-1 to II-12 etching agent were the same as the polishing liquid compo where the aliphatic carboxylic acid having 7 to 24 carbon sition. The polishing speed was obtained by polishing a rolled atoms is formulated in the polishing liquid composition Sup copper plate of a diameter of 50 mm and a plate thickness of pressed the etching speed and the dishing is not generated 5 1 mm, determining a change in the thickness before and after without Substantially lowering the polishing speed, as com polishing, and dividing the resultant value by a polishing pared to the polishing liquid compositions of Comparative time. Incidentally, the thickness of the copper plate was mea Examples II-1 to II-5. II-11 and II-12 where the aliphatic sured by using a high-precision digital analyzer "MINIAX” carboxylic acid is not formulated. 10 commercially available from K. K. Tokyo Seimitsu. Here, In addition, the polishing liquid composition of Compara each of the relative polishing speeds for Examples III-1, III-2, tive Example II-6 where two kinds of aliphatic carboxylic III-4, III-5, and III-7 was calculated based on Comparative acids having 6 or less carbon atoms are used in combination Example III-1; the relative polishing speed for Example III-6 without using the aliphatic carboxylic acid having 7 to 24 was calculated based on Comparative Example III-2; the carbon atoms has high etching speed and the dishing gener 15 relative polishing speed for Example III-3 was calculated ated. based on Comparative Example III-3; and the relative polish In addition, it is found that all of the polishing liquid ing speed for Example III-8 was calculated based on Com composition of Comparative Example II-7 where two kinds parative Example III-4. Incidentally, apart from the above, the of the aliphatic carboxylic acids having 7 to 24 carbon atoms relative polishing speed for Comparative Example III-5 was are used in combination; the polishing liquid composition of Comparative Example II-8 where the organic acid capable of calculated based on Comparative Example III-1. forming an aqueous salt with copper is not formulated; and Relative Etching Speed the polishing liquid composition of Comparative Example The relative etching speed is a value obtained by dividing II-9 where benzotriazole for Suppressing etching is formu lated have extremely low polishing speeds, and that the pol an etching speed of the polishing liquid composition com ishing liquid composition of Comparative Example II-10 prising the above amine compound and/or its salt by an etch where ammonium polyacrylate is formulated has copper Sur ing speed 'c' of a polishing liquid composition not contain face with roughening generated. ing the above amine compound and/or its salt but having the Therefore, an even higher polishing speed can be realized 30 same kinds and the amounts of an abrasive, an oxidizing agent by using the aliphatic carboxylic acid having 7 to 24 carbon and an etching agent as the polishing liquid composition. atoms in combination with an etching agent, and the dishing Here, each of the relative etching speeds for Examples III-1, can be prevented. III-2, III-4, III-5, and III-7 was calculated based on Compara Especially, from the viewpoint of keeping the low-foam tive Example III-1; the relative etching speed for Example ability during polishing, it is more preferable that the aliphatic 35 carboxylic acid having 7 to 24 carbonatoms is heptanoic acid, III-6 was calculated based on Comparative Example III-2; the octanoic acid and nonanoic acid. relative etching speed for Example III-3 was calculated based on Comparative Example III-3; and the relative etching speed

EXAMPLES III-1 TO III-8 AND COMPARATIVE 40 for Example III-8 was calculated based on Comparative EXAMPLES III-1 TO III-5 Example III-4. Incidentally, apart from the above, the relative etching speed for Comparative Example III-5 was calculated Each of the etching agents shown in Table 5, and the amine based on Comparative Example III-1. Incidentally, each the compound were mixed with a given amount of water, so as to etching speeds for each the polishing liquid compositions of have the proportion shown in Table 5, and thereafter an aque 45 ous ammonia was added so as to have a pH of the liquid Examples III-1 to III-8 and Comparative Example III-5 was a mixture of 6 to 8. Further, hydrogen peroxide was added so as value measured under the same conditions as the above etch to have a proportion shown in Table 5. Further, 5% by weight ing test C described above, except for using these polishing portion of an abrasive shown in Table 5 was mixed with liquid compositions. stirring, and thereafter a pH of the liquid mixture was adjusted 50 to the value shown in Table 5, to give a polishing liquid Dishing composition. Incidentally, each of the used abrasives was Dishing was evaluated in the same manner as above. Inci fumed silica (primary particle size: 50 nm) and colloidal dentally, when there were no recesses having sizes of 0.15um silica (primary particle size: 100 nm). In addition, a rolled or more in the cross section profile of the copper interconnec copper plate of a diameter of 50 mm and a plate thickness of 55 1 mm was polished under the same conditions as above by tion tested, it was evaluated as absence of dishing, and when single-sided polishing machine. there were recesses having sizes of 0.15 um or more, it was In addition, the properties of the polishing liquid compo evaluated as presence of dishing, which are respectively sition Such as relative polishing speed, relative etching speed, denoted in Table 5 as “absence' or “presence.” and dishing of the surface to be polished were evaluated in 60 Here, the etching speed 'c' of the polishing liquid compo accordance with the following methods. The results thereof sitions used for Comparative Examples III-1 to III-4 were as are shown in Table 5. follows. Comparative Example III-1: 50 A/min Relative Polishing Speed Comparative Example III-2: 100 A/min The relative polishing speed is a value obtained by dividing 65 the polishing speed of a polishing liquid composition by a Comparative Example III-3:50 A/min polishing speed of a comparative example where the kinds Comparative Example III-4: 50 A/min US 7,604,751 B2 31 32

TABLE 5 Hydrogen Amine Compound Etching Agent Peroxide

Content Content Content (% by (% by (% by Abrasive Kind wt.) Kind wt.) wt.) Kind pH

Ex. No. -1 Octylamine 0.8 Glycolic 2.0 4.0 Colloidal 7.6 acid Silica -2 Nonylamine 0.5 Glycolic 2.0 4.0 Colloidal 7.6 acid Silica -3 Decylamine 1.0 Hydrochloric 2.0 2.0 Colloidal 7.7 acid Silica -4 Oleylamine 0.4 Glycolic 2.0 4.0 Colloidal 7.6 acid Silica -S Dimethyl- 0.5 Glycolic 2.0 4.0 Colloidal 7.6 dodecylamine acid Silica -6 Dimethyl- 0.8 Citric 2.0 2.0 Fumed 7.6 dodecylamine acid Silica -7 Dodecyl- 0.8 Glycolic 2.0 4.0 Colloidal 7.6 diethanolamine acid Silica -8 Octylamine 0.5 Glycolic 2.0 Colloidal 7.6 acid Silica Comp. Ex. No.

-1 — Glycolic 2.0 4.0 Colloidal 7.6 acid Silica -2 — Citric 2.0 2.0 Fumed 7.6 acid Silica -3 — Hydrochloric 2.0 2.0 Colloidal 7.7 acid Silica -4 — Glycolic 2.0 Colloidal 7.6 acid Silica -S Benzotriazole 0.3 Glycolic 2.0 4.0 Colloidal 7.6 acid Silica

Evaluation for Properties Relative Relative Comp. Ex. To Polishing Etching Which Evaluation Speed Speed Was Based Dishing

Ex. No.

-1 1.O 0.1 or less Comp. Ex. III-1 Absence -2 O.9 0.1 or less Comp. Ex. III-1 Absence -3 1.O 0.1 or less Comp. Ex. III-3 Absence -4 O.9 0.1 or less Comp. Ex. III-1 Absence -S O.9 0.1 or less Comp. Ex. III-1 Absence -6 O.9 0.1 or less Comp. Ex. III-2 Absence -7 O.9 0.1 or less Comp. Ex. III-1 Absence -8 O.9 0.1 or less Comp. Ex. III-4 Absence Comp. Ex. No.

-1 1.O 1.O Presence -2 1.O 1.O Presence -3 1.O 1.O Presence -4 1.O 1.O Presence -S 0.1 or less 0.1 or less Comp. Ex. III-1 :

Note *: The polishing speed was too slow to be evaluated.

It is found from the results of Table 5 that all of the polish In addition, it is found that the polishing liquid composition ing liquid compositions of Examples III-1 to III-8 where the 60 of Comparative Example III-5 where benzotriazole acting to amine compound is formulated in the polishing liquid com Suppressing etching was used in place of the amine com position Suppressed the etching speed and the dishing is not pound, the polishing speed is extremely low. generated without Substantially lowering the polishing speed, as compared to the polishing liquid compositions of Com 65 Therefore, it is found that an even higher polishing speed parative Examples III-1 to III-4 where the amine compound is can be realized by using the amine compound in combination not formulated. with an etching agent, and the dishing can be prevented. US 7,604,751 B2 33 34 Especially, from the viewpoint of keeping the low-foam 3. The method according to claim 1, wherein the etching ability during polishing, it is more preferable that the amine agent is at least one compound selected from the group con compound is heptylamine, octylamine and nonylamine. sisting of Since the polishing liquid composition of the present A: aliphatic organic acids having 6 or less carbon atoms invention is used for polishing a Surface to be polished com 5 and one to three carboxyl groups; prising an insulating layer and a metal layer, there are exhib B: aromatic organic acids having 7 to 10 carbonatoms and ited such effects that the polishing speed of the metal film is one to four carboxyl groups; maintained, that the etching speed is suppressed, and defects C: organic acids having 6 or less carbon atoms and one to Such as dishing in the interconnection metal layer is not four phosphonic groups; and generated. 10 D: polyaminocarboxylic acids having in a molecule two or more structures represented by the formula (III): The invention claimed is: 1. A method comprising chemical mechanical polishing a Surface comprising an insulating layer and a metal layer using (III) a polishing liquid composition comprising 15 an amine compound represented by the following general -N-CHCOOH. formula: 4. The method according to claim 3, wherein the etching R4 agent is at least one compound selected from the group con A sisting of glycolic acid, gluconic acid, citric acid, and ami R3-N notri (methylene-phosphonic acid). Ys 5. The method according to claim 1, wherein R is a linear or branched, alkyl or alkenyl group having 5 to 14 carbon atOmS. wherein 25 6. The method according to claim 1, wherein the polishing R is a linear or branched alkyl group having 4 to 18 liquid composition comprises the abrasive. carbon atoms, or 7. The method according to claim 3, wherein the etching a linear or branched alkenyl group having 4 to 18 agent comprises a compound from group A. carbon atoms, or 8. The method according to claim 3, wherein the etching an aryl group having 6 to 18 carbon atoms, or 30 agent comprises a compound from group B. an aralkyl group having 7 to 18 carbon atoms; 9. The method according to claim 3, wherein the etching each of RandR, which may be identical or different, is agent comprises a compound from group C. a linear alkyl group having 1 to 8 carbon atoms or 10. The method according to claim 3, wherein the etching a branched alkyl group having 3 to 8 carbonatoms, or agent comprises a compound from group D. a group represented by H. (OR) wherein R is a 35 11. The method according to claim 1, wherein R is a linear linear alkylene group having 1 to 3 carbon atoms, or branched, alkyl or alkenyl group having 7 to 10 carbon O atoms, and R and Rare independently a linear alkyl group a branched alkylene group having 3 carbon atoms; having 1 or 2 carbon atoms or a group represented by and H (OR) , wherein R is an alkylene group having 2 Z is a number of 1 to 20, and/or a salt thereof, 40 carbon atoms, and Z is a number of 1 to 4. an etching agent, 12. The method according to claim 1, wherein the metal at least one of an oxidizing agent and an abrasive, and layer comprises a metal selected from the group consisting of Water. copper, copper alloys, aluminum, aluminum alloys, and tung 2. The method according to claim 1, wherein the polishing Sten. liquid composition comprises the oxidizing agent. UNITED STATES PATENT AND TRADEMARK OFFICE CERTIFICATE OF CORRECTION

PATENT NO. : 7,604,751 B2 Page 1 of 1 APPLICATION NO. : 1 1/434.074 DATED : October 20, 2009 INVENTOR(S) : Yoneda et al. It is certified that error appears in the above-identified patent and that said Letters Patent is hereby corrected as shown below:

On the Title Page:

The first or sole Notice should read --

Subject to any disclaimer, the term of this patent is extended or adjusted under 35 U.S.C. 154(b) by 157 days.

Signed and Sealed this Fourteenth Day of December, 2010

David J. Kappos Director of the United States Patent and Trademark Office