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Methods of Preparing Thin Films by Atomic Layer

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Methods of Preparing Thin Films by Atomic Layer (19) TZZ __Z¥_T (11) EP 2 191 034 B1 (12) EUROPEAN PATENT SPECIFICATION (45) Date of publication and mention (51) Int Cl.: of the grant of the patent: C23C 16/455 (2006.01) 13.03.2013 Bulletin 2013/11 (86) International application number: (21) Application number: 08799401.8 PCT/US2008/075831 (22) Date of filing: 10.09.2008 (87) International publication number: WO 2009/036046 (19.03.2009 Gazette 2009/12) (54) METHODS OF PREPARING THIN FILMS BY ATOMIC LAYER DEPOSITION USING MONOCYCLOPENTADIENYL TRIAMINO ZIRCONIUM PRECURSORS VERFAHREN ZUR HERSTELLUNG VON DÜNNEN FILMEN DURCH ATOMLAGENABSCHEIDUNG UNTER VERWENDUNG VON MONOCYCLOPENTADNIEYLTRIAMINOZIRCONIUM- VORLÄUFERN PROCÉDÉS DE PRÉPARATION DE FILMS MINCES PAR DÉPÔT DE COUCHES ATOMIQUES À L’AIDE DE PRÉCURSEURS DE MONOCYCLOPENTADIÉNYL TRIAMINO ZIRCONIUM (84) Designated Contracting States: • DAVIES, Hywel, Owen AT BE BG CH CY CZ DE DK EE ES FI FR GB GR Mold, Flintshire CH7 1PW (GB) HR HU IE IS IT LI LT LU LV MC MT NL NO PL PT • ODEDRA, Rajesh RO SE SI SK TR Altrincham, Cheshire WA14 5NU (GB) (30) Priority: 14.09.2007 US 972451 P (74) Representative: Brown, David Leslie Haseltine Lake LLP (43) Date of publication of application: Redcliff Quay 02.06.2010 Bulletin 2010/22 120 Redcliff Street Bristol (73) Proprietor: Sigma Aldrich Co. LLC BS1 6HU (GB) St. Louis, MO 63103 (US) (56) References cited: (72) Inventors: WO-A-2006/131751 WO-A-2007/066546 • HEYS, Peter, Nicholas Crewe, Cheshire CW2 6QE (GB) • "Book of Abstracts: E-MRS 2007 Fall Meeting" • KINGSLEY, Andrew [Online] 31 August 2007 (2007-08-31), Newton, Chester CH2 2FA (GB) PIELASZEK RESEARCH , POLAND , • SONG, Fuquan XP002507005 ISBN: 83-89585-16-2 Retrieved Eastham, Wirral CH62 8EX (GB) from the Internet: URL:http: • WILLIAMS, Paul //www.science24.com/events/1302/b Wirral, Merseyside CH62 2AY (GB) oa/boa.pdf> cited in the application page 87, • LEESE, Thomas right-hand column - page 88, left-hand column Alsager, Stoke-On-Trent ST7 2HD (GB) Note: Within nine months of the publication of the mention of the grant of the European patent in the European Patent Bulletin, any person may give notice to the European Patent Office of opposition to that patent, in accordance with the Implementing Regulations. Notice of opposition shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention). EP 2 191 034 B1 Printed by Jouve, 75001 PARIS (FR) EP 2 191 034 B1 Description FIELD OF THE INVENTION 5 [0001] The present invention relates to methods of preparing thin films by atomic layer deposition (ALD) using zirco- nium-based precursors. BACKGROUND OF THE INVENTION 10 [0002] ALD is a known method for the deposition of thin films. It is a self-limiting, sequential unique film growth technique based on surface reactions that can provide atomic layer control and deposit conformal thin films of materials provided by precursors onto substrates of varying compositions. In ALD, the precursors are separated during the reaction. The first precursor is passed over the substrate producing a monolayer on the substrate. Any excess unreacted precursor is pumped out of the reaction chamber. A second precursor is then passed over the substrate and reacts with the first 15 precursor, forming a monolayer of film on the substrate surface. This cycle is repeated to create a film of desired thickness. [0003] ALD processes have applications in nanotechnology and fabrication of semiconductor devices such as capacitor electrodes, gate electrodes, adhesive diffusion barriers and integrated circuits. Further, dielectric thin films having high dielectric constants (permittivities) are necessary in many sub-areas of microelectronics and optelectionics. The continual decrease in the size of microelectronics components has increased the need for the use of such dielectric films. 20 [0004] Japanese Patent Application No. P2005-171291 reports titanium-based precursors for use in chemical vapor deposition. [0005] International Patent Publication No. WO 2007/066546 of Tri Chemical Laboratories, published on 14 June 2007, reports hafnium-based precursors for forming a hafnium-based film by a chemical vapor deposition process or an atomic layer deposition process. 25 [0006] International Publication No. WO 2007/141059 of Air Liquide Societe, published on 13 December 2007, reports a method of forming dielectric films such as hafnium or zirconium oxide films. [0007] An abstract by Niinistö J., et al. entitled "ALD of ZrO2 Thin Films Exploiting Novel Mixed Alkylamido-Cyclopen- tadienyl Precursors" (See http://science24.com/paper/11894) reports the use of (EtCp)Zr(NMe2)3 for forming a metal oxide film by ALD. 30 [0008] Current ALD does provide the required performance to implement new processes for fabrication of next gen- eration devices, such as semiconductors. For example, improved thermal stability, higher volatility or increased deposition rates are needed. SUMMARY OF THE INVENTION 35 [0009] The invention provides methods of forming metal-containing films by liquid injection atomic layer deposition as defined in the claims 1-11. [0010] Other embodiments, including particular aspects of the invention, will be evident from the detailed description that follows. 40 BRIEF DESCRIPTION OF THE DRAWINGS [0011] Figure 1 is a graphical representation of thermogravimetric analysis (TGA) data demonstrating mg vs. temper- ature/time of (MeCp)Hf(OtBu)3. 45 [0012] Figure 2 is a graphical representation of TGA data demonstrating mg vs. temperature/time of (MeCp)Hf (NMe2)3. [0013] Figure 3 is a graphical representation of TGA data demonstrating mg vs. temperature/time of (MeCp)Zr (OtBu)3. [0014] Figure 4 is a graphical representation of TGA data demonstrating mg vs. temperature/time of (MeCp)Zr (NMe2)3. DETAILED DESCRIPTION OF THE INVENTION 50 [0015] In various aspects of the invention, methods are provided which utilize zirconium-based precursors to form various zirconium-containing films by ALD. [0016] The methods of the invention are used to create or grow Zirconium containing thin films which display high dielectric constants. A dielectric thin film as used herein refers to a thin film having a high permittivity. The films created 55 herein by ALD are dielectric thin films. 2 EP 2 191 034 B1 A. Definitions [0017] As used herein, the term "precursor" refers to an organometallic molecule, complex and/or compound which is delivered to a substrate for deposition to form a thin film by ALD. 5 [0018] The organometallic precursor of the invention has at least one metallic center comprising a transition metal ("M"). In particular, there is one metal center and M is hafnium or zirconium. [0019] The term "Cp" refers to a cyclopentadienyl (C 5H5) ligand which is bound to a transition metal. As used herein, all five carbon atoms of the Cp ligand are bound to the metal center ηin5 -coordination by n bonding, therefore the precursors of the invention are π complexes. 10 [0020] The term "alkyl" refers to a saturated hydrocarbon chain of 1 to about 6 carbon atoms in length, such as, but not limited to, methyl, ethyl, propyl and butyl. The alkyl group may be straight-chain or branched-chain. For example, as used herein, propyl encompasses both n-propyl and iso-propyl; butyl encompasses n-butyl, sec-butyl, iso-butyl and tert-butyl. Further, as used herein, "Me" refers to methyl, and "Et" refers to ethyl. [0021] The term "amino" herein refers to an optionally substituted monovalent nitrogen atom (i.e., -NR 1R2, where R1 15 and R2 can be the same or different). Examples of amino groups encompassed by the invention include but are not limited to 20 and 25 Further, the nitrogen atom of this amino group is covalently bonded to the metal center which together may be referred to as an "amide" group (i.e. 30 35 This can be further referred to as an "ammono" group or inorganic amide, for example 40 B. Methods of Use 45 [0022] In a first embodiment, a method of forming a metal-containing film by atomic layer deposition is provided. The method comprises delivering at least one precursor to a substrate, wherein the at least one precursor corresponds in structure to Formula I: 50 55 3 EP 2 191 034 B1 wherein: M is Hf or Zr; R is C1-C6-alkyl; 5 n is zero, 1, 2, 3, 4 or 5; L is C1-C6-alkoxy or amino, wherein the amino is optionally independently substituted 1 or 2 times with C 1-C6-alkyl. [0023] In one embodiment, the at least one precursor corresponds in structure to Formula I, wherein M is Hf 10 R is methyl, ethyl or propyl; n is zero, 1 or 2; and L is selected from the group consisting of methoxy, ethoxy, propoxy, butoxy, dimethylamino, ethylmethylamino, and diethylamino. [0024] In another embodiment, the at least one precursor corresponds in structure to Formula I, wherein 15 M is Hf R is methyl or ethyl; n is 1 or 2; and L is selected from the group consisting of methoxy, ethoxy, propoxy, butoxy, dimethylamino, ethylmethylamino, and diethylamino. 20 [0025] In another embodiment, the at least one precursor corresponds in structure to Formula I, wherein M is Hf R is methyl or ethyl; n is 1; and L is selected from the group consisting of methoxy, ethoxy, propoxy, and butoxy. 25 [0026] In another embodiment, the at least one precursor corresponds in structure to Formula I, wherein M is Zr; R is methyl, ethyl or propyl; n is zero, 1 or 2; and L is selected from the group consisting of methoxy, ethoxy, propoxy, butoxy, dimethylamino, ethylmethylamino, and 30 diethylamino. [0027] In another embodiment, the at least one precursor corresponds in structure to Formula I, wherein M is Zr; R is methyl or ethyl; n is 1 or 2; and 35 L is selected from the group consisting of methoxy, ethoxy, propoxy, butoxy, dimethylamino, ethylmethylamino, and diethylamino.
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