US010648087B2 (12 ) United States Patent ( 10 ) Patent No.: US 10,648,087 B2 Lansalot -Matras et al. (45 ) Date of Patent : May 12 , 2020 (54 ) ETCHING REACTANTS AND PLASMA - FREE (51 ) Int. CI. ETCHING PROCESSES USING THE SAME C23F 1/12 (2006.01 ) HOIL 21/311 (2006.01 ) ( 71) Applicants :L’Air Liquide, Société Anonyme pour ( Continued ) l'Etude et l'Exploitation des Procédés (52 ) U.S. Ci. Georges Claude, Paris (FR ) ; Clément CPC C23F 1/12 ( 2013.01) ; C23C 8/80 Lansalot- Matras , Princeton , NJ (US ) ; (2013.01 ) ; HOIL 21/31116 ( 2013.01 ) ; Jooho Lee , Seoul (KR ) ; Jean -Marc ( Continued ) Girard , Versailles ( FR ) ; Nicolas (58 ) Field of Classification Search Blasco , Grenoble (FR ) ; Satoko CPC C23F 1/12 Gatineau , Seoul (KR ) See application file for complete search history. ( 72 ) Inventors: Clément Lansalot- Matras , Princeton , (56 ) References Cited NJ (US ) ; Jooho Lee, Seoul (KR ) ; Jean -Marc Girard , Versailles ( FR ) ; U.S. PATENT DOCUMENTS Nicolas Blasco , Grenoble (FR ) ; Satoko 4,343,676 A 8/1982 Tarng Gatineau , Seoul (KR ) 4,793,897 A 12/1988 Dunfield et al . ( 73 ) Assignee : L’Air Liquide, Société Anonyme pour ( Continued ) l'Exploitation et l'Etude des Procédés Georges Claude, Paris (FR ) FOREIGN PATENT DOCUMENTS JP H09 228053 9/1997 ( * ) Notice : Subject to any disclaimer, the term of this JP H10 113536 5/1998 patent is extended or adjusted under 35 U.S.C. 154 ( b ) by 0 days . (Continued ) (21 ) Appl. No.: 15 /774,892 OTHER PUBLICATIONS Aarik , J. et al. , “Mechanisms of suboxide growth and etching in ( 22 ) PCT Filed : Sep. 1 , 2016 atomic layer deposition of tantalum oxide from TaCl, and H20 , " Applied Surface Science 103 ( 1996 ), 331-341. ( 86 ) PCT No.: PCT/ US2016 / 049857 (Continued ) § 371 ( c ) ( 1 ) , ( 2 ) Date : May 9 , 2018 Primary Examiner Roberts P Culbert (74 ) Attorney , Agent, or Firm — Yan Jiang ; Patricia E. ( 87 ) PCT Pub . No.: WO2016 / 172740 McQueeney PCT Pub . Date : Oct. 27 , 2016 (57 ) ABSTRACT (65 ) Prior Publication Data Disclosed are processes of removing layers from substrates US 2018/0327913 A1 Nov. 15 , 2018 using fluorinated reactants having the formula MF_( adduct) n ' wherein x ranges from 2 to 6 inclusive; n ranges from 0 to 5 inclusive; M is selected from the group consisting of P , Related U.S. Application Data Ti, Zr, Hf, V , Nb , Ta ,Mo , and W ; and the adduct is a neutral (60 ) Provisional application No.62 / 253,507 , filed on Nov. organic molecule selected from THF , dimethylether, diethy 10 , 2015 . (Continued ) 6 M 3 8 11 2 11 9 US 10,648,087 B2 Page 2 lether , glyme , diglyme, triglyme, polyglyme , dimethylsul FOREIGN PATENT DOCUMENTS phide , diethylsulphide, or methylcyanide . The fluorinated reactants dry etch the nitride layers without utilizing any JP 2007 141918 6/2007 plasma. WO WO 2015 194178 12/2015 16 Claims, 12 Drawing Sheets OTHER PUBLICATIONS Baroch , C.J. et al. , “ Preparation of zirconium from zirconium tetrafluoride, ” U.S. Atomic Energy Commission , Physical Sciences ( 51 ) Int. Cl. Reading Room , Unclassified ISC - 720 , Ames Laboratory , Iowa State HOIL 213213 ( 2006.01) College, May 31 , 1956 , 1-18 . HOIL 21/67 (2006.01 ) Jenkins , W.A. et al. , “ Tantalum oxychloride, " J. Inorg . Nucl . Chem . C23C 8/80 ( 2006.01) 1959 , 11 , 163-164 . HOIL 21/02 (2006.01 ) Knapas, K. et al. , “ Etching of Nb205 thin films by NbC15 ," Chem . B08B 9/08 ( 2006.01 ) Vap. Deposition 2009 , 15, 269-273 . ( 52 ) U.S. Ci. Kukli , K. et al ., " Atomic layer deposition of tantalum oxide thin CPC .. HOIL 21/31122 ( 2013.01 ) ; HOIL 21/32135 films form iodide precursor, ” Chem . Mater . 2001, 13 , 122-128 . ( 2013.01 ) ; HOIL 21/67069 (2013.01 ) ; B08B Mercier , F. et al. , “ Niobium nitride thin films deposited by high 9/083 (2013.01 ) ; HOIL 21/02244 ( 2013.01 ) ; temperature chemical vapor deposition ,” Surface & Coatings Tech HOIL 21/02247 (2013.01 ) nology 260 (2014 ) 126-132 . Sha , L. et al. , “ Ion -enhanced chemical etching of ZrO2 in a chlorine ( 56 ) References Cited discharge, " J. Vac . Sci . Technol. A 20 ( 5 ), Sep./Oct. 2002 , 1525 1531 . U.S. PATENT DOCUMENTS Sha , L. et al. , “ Plasma etching selectivity of ZrO2 to Si in BC12/ C12 5,855,689 A 1/1999 Akiyama plasmas, ” J. Vac . Sci. Technol. A 21 (6 ) , Nov./Dec. 2003 , 1915-1922 . 5,879,646 A 3/1999 Orihara et al . Sungauer, E. et al. , “ Etching mechanisms of HfO2, SiO2, and 6,077,451 A 6/2000 Takenaka et al. poly -Si substrates in BC1z plasmas , " J. Vac . Sci. Technol. B 25 ( 5 ) , 6,143,191 A 11/2000 Baum et al. Sep./Oct. 2007 , 1640-1646 . 6,261,934 B1 7/2001 Kraft et al. Woo , J.-C. et al. , “ A study on dry etching for profile and selectivity 6,284,052 B2 9/2001 Nguyen et al. of ZrO2 thin films over Si by using high density plasma, ” Thin Solid 9,130,158 B1 9/2015 Shen et al. 9,391,267 B2 7/2016 Shen et al. Films 517 (2009 ) , 4246-4250 . 2005/0019977 Al 1/2005 Shiva International Search Report and Written Opinion for corresponding 2005/0082002 A1 4/2005 Sato et al. PCT// US2016 / 049857 , dated Dec. 19 , 2016 . 2015/0050807 A1 * 2/2015 Wu HO1L 21/28556 438/669 * cited by examiner U.S. Patent May 12 , 2020 Sheet 1 of 12 US 10,648,087 B2 6 3 8 1 2 11 9 FIG 1 6 7 - 3 co 1 - - -1 - 1 2 8 1 11 14 FIG 2 U.S. Patent May 12 , 2020 Sheet 2 of 12 US 10,648,087 B2 5 ** O * 4.44 64 Y$ > g Sii $ ***** FIG 3 U.S. Patent May 12 , 2020 Sheet 3 of 12 US 10,648,087 B2 302 106 300 301 201 103 200 101 102. ) 1400 105 108 FIG 4 U.S. Patent May 12 , 2020 Sheet 4 of 12 US 10,648,087 B2 50 Nb205 Etchingrate[A/sec] 40 Ta205 A ZrO2 30 X HfO2 * TiO2 X X O Al2O3 10 + SIO2 0 250 270 290 310 330 350 370 390 410 Temperature [ ° C ] FIG 5 U.S. Patent May 12 , 2020 Sheet 5 of 12 US 10,648,087 B2 160 Nb205 OTa205 120 AZrO2 Etchingrate(A/sec) XHfO2 ?TiO2 X OA1203 + SiO2 20 ATIN 100 150 200 250 300 350 Temperature ( ° C ) FIG6 U.S. Patent May 12 , 2020 Sheet 6 of 12 US 10,648,087 B2 Nb205 350 OTa205 X 300 AZrO2 pong 250 XHfO2 Etchingrate(A/sec) 200 XTIO2 150 X OAI203 + SiO2 ? -S?N 50 CE 100 200 250 300 350 Temperature (° C ] FIG 7 U.S. Patent May 12 , 2020 Sheet 7 of 12 US 10,648,087 B2 Metallic layer Substrate Oxidation / Nitrization Metal oxide / nitride layer Metallic layer Substrate Etching Metallic layer Substrate Oxidation / Nitrization Metal oxidel nitride layer Metallic layer Substrate Etching Metallic layer Substrate Oxidation / Nitrization Metal oxidel nitride layer Substrate Etching Substrate FIG 8 U.S. Patent May 12 , 2020 Sheet 8 of 12 US 10,648,087 B2 WO w SIOL FIG 9a TINTI SiO2 lum FIG 9b U.S. Patent May 12 , 2020 Sheet 9 of 12 US 10,648,087 B2 Wo TINTI SiO , lum FIGFIG 909c Wo. W TINTI lum FIG 9d U.S. Patent May 12 , 2020 Sheet 10 of 12 US 10,648,087 B2 Tungsten oxide Tungsten TINTI FIG 10 U.S. Patent May 12 , 2020 Sheet 11 of 12 US 10,648,087 B2 Tungsten oxide 2 Tungsten FIG 11a Tungsten oxide Tungsten7 FIG 11b Tunesien oxida Tungste FIG 110 U.S. Patent May 12 , 2020 Sheet 12 of 12 US 10,648,087 B2 Tungsten oxide Tungsten FIG 12a Tungsten oxide Tungsten VINNN FIG 12b Tungsten FIG 12c US 10,648,087 B2 1 2 ETCHING REACTANTS AND PLASMA- FREE pressing the silicon etch rate (Sha et al ., J. Vac . Sci . Technol. , ETCHING PROCESSES USING THE SAME A 21 (2003 ) 1915 ) ; and an investigation of the etching characteristics ( etch rate , selectivity to Si) of ZrO2 thin films CROSS REFERENCE TO RELATED in the HBr/ SF high density plasma system ( Woo et al. , Thin APPLICATIONS 5 Solid Films 517 (2009 ) 4246-4250 ) . Dry plasma etching processes have some disadvantages The present application is a 371 of International PCT such as the cost of the equipment, the use of toxic or Application PCT /US2016 / 049857 , filed Sep. 1 , 2016 , which corrosive gases , and potential damage to the underlying claims the benefit of U.S. Provisional Application Ser. No. substrate . 62 /253,507 filed Nov. 10 , 2015 , herein incorporated by 10 H. Schafer (Z. Anorg . Allg . Chem . 1960, 305 , 341 ) and W. reference in its entirety for all purposes . A. Jenkins ( J. Inorg . Nucl . Chem . 1959 , 11, 163 ) described the thermal etching process of Tantalum oxide ( Ta203) at TECHNICAL FIELD temperatures between 200 and 350 ° C. according to the Disclosed are thermal processes of removing layers from 15 equation Ta ,05 ( ) + 3TaCl: ( ) > 5 TaOC13 ( g ). The reaction is substrates using fluorinated reactants having the formula endothermic ( ~ 35 kcal/ mol ) and an increase of the etching MF ( adduct) n , wherein x ranges from 2 to 6 inclusive ; n rate with temperature was observed . Nonetheless, the etch ranges from 0 to 5 inclusive ; M is an element selected from ing rate was too slow ( ~6x10-2 A /Cy ) to be suitable to the group consisting of P , Ti, Zr, Hf, V , Nb, Ta, Mo, and W ; replace existing plasma based processes. Knapas et al . and the adduct is a neutral organic molecule selected from 20 (Chem . Vap . Deposition 2009, 15 , pp . 269-273) found that THF, dimethylether , diethylether, glyme , diglyme, triglyme , NbCl, etches Nb20 , film producing volatile NbOC1z .