JP4710915B2 - Polishing method - Google Patents
Polishing method Download PDFInfo
- Publication number
- JP4710915B2 JP4710915B2 JP2008028775A JP2008028775A JP4710915B2 JP 4710915 B2 JP4710915 B2 JP 4710915B2 JP 2008028775 A JP2008028775 A JP 2008028775A JP 2008028775 A JP2008028775 A JP 2008028775A JP 4710915 B2 JP4710915 B2 JP 4710915B2
- Authority
- JP
- Japan
- Prior art keywords
- polishing
- acid
- barrier layer
- copper
- film
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 238000005498 polishing Methods 0.000 title claims description 143
- 238000000034 method Methods 0.000 title claims description 31
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 58
- 239000004020 conductor Substances 0.000 claims description 51
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 47
- 229910052802 copper Inorganic materials 0.000 claims description 47
- 239000010949 copper Substances 0.000 claims description 47
- 230000004888 barrier function Effects 0.000 claims description 46
- 229910052751 metal Inorganic materials 0.000 claims description 39
- 239000002184 metal Substances 0.000 claims description 39
- 229910000881 Cu alloy Inorganic materials 0.000 claims description 37
- 239000007788 liquid Substances 0.000 claims description 34
- 239000006061 abrasive grain Substances 0.000 claims description 31
- 239000007800 oxidant agent Substances 0.000 claims description 31
- 239000000758 substrate Substances 0.000 claims description 29
- 239000002245 particle Substances 0.000 claims description 27
- 239000000377 silicon dioxide Substances 0.000 claims description 25
- MZLGASXMSKOWSE-UHFFFAOYSA-N tantalum nitride Chemical compound [Ta]#N MZLGASXMSKOWSE-UHFFFAOYSA-N 0.000 claims description 24
- 229910052715 tantalum Inorganic materials 0.000 claims description 23
- GUVRBAGPIYLISA-UHFFFAOYSA-N tantalum atom Chemical group [Ta] GUVRBAGPIYLISA-UHFFFAOYSA-N 0.000 claims description 23
- 230000001681 protective effect Effects 0.000 claims description 22
- 235000012239 silicon dioxide Nutrition 0.000 claims description 22
- 239000003795 chemical substances by application Substances 0.000 claims description 21
- 229910001362 Ta alloys Inorganic materials 0.000 claims description 16
- 150000003482 tantalum compounds Chemical class 0.000 claims description 16
- 230000001590 oxidative effect Effects 0.000 claims description 14
- 229920003169 water-soluble polymer Polymers 0.000 claims description 14
- 239000002253 acid Substances 0.000 claims description 13
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 13
- KRKNYBCHXYNGOX-UHFFFAOYSA-N citric acid Chemical compound OC(=O)CC(O)(C(O)=O)CC(O)=O KRKNYBCHXYNGOX-UHFFFAOYSA-N 0.000 claims description 12
- 239000012964 benzotriazole Substances 0.000 claims description 10
- OFOBLEOULBTSOW-UHFFFAOYSA-N Malonic acid Chemical compound OC(=O)CC(O)=O OFOBLEOULBTSOW-UHFFFAOYSA-N 0.000 claims description 9
- QRUDEWIWKLJBPS-UHFFFAOYSA-N benzotriazole Chemical compound C1=CC=C2N[N][N]C2=C1 QRUDEWIWKLJBPS-UHFFFAOYSA-N 0.000 claims description 9
- AEMRFAOFKBGASW-UHFFFAOYSA-N Glycolic acid Chemical compound OCC(O)=O AEMRFAOFKBGASW-UHFFFAOYSA-N 0.000 claims description 8
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims description 8
- 239000011164 primary particle Substances 0.000 claims description 8
- 150000003839 salts Chemical class 0.000 claims description 8
- 239000008119 colloidal silica Substances 0.000 claims description 7
- BJEPYKJPYRNKOW-REOHCLBHSA-N (S)-malic acid Chemical compound OC(=O)[C@@H](O)CC(O)=O BJEPYKJPYRNKOW-REOHCLBHSA-N 0.000 claims description 6
- 229920002125 Sokalan® Polymers 0.000 claims description 6
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 claims description 6
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 claims description 6
- BJEPYKJPYRNKOW-UHFFFAOYSA-N alpha-hydroxysuccinic acid Natural products OC(=O)C(O)CC(O)=O BJEPYKJPYRNKOW-UHFFFAOYSA-N 0.000 claims description 6
- YBMRDBCBODYGJE-UHFFFAOYSA-N germanium dioxide Chemical compound O=[Ge]=O YBMRDBCBODYGJE-UHFFFAOYSA-N 0.000 claims description 6
- 239000001630 malic acid Substances 0.000 claims description 6
- 235000011090 malic acid Nutrition 0.000 claims description 6
- 239000004584 polyacrylic acid Substances 0.000 claims description 6
- 239000011163 secondary particle Substances 0.000 claims description 6
- 229920002845 Poly(methacrylic acid) Polymers 0.000 claims description 5
- 150000007524 organic acids Chemical class 0.000 claims description 5
- 239000002002 slurry Substances 0.000 claims description 5
- FEWJPZIEWOKRBE-JCYAYHJZSA-N Dextrotartaric acid Chemical compound OC(=O)[C@H](O)[C@@H](O)C(O)=O FEWJPZIEWOKRBE-JCYAYHJZSA-N 0.000 claims description 4
- FEWJPZIEWOKRBE-UHFFFAOYSA-N Tartaric acid Natural products [H+].[H+].[O-]C(=O)C(O)C(O)C([O-])=O FEWJPZIEWOKRBE-UHFFFAOYSA-N 0.000 claims description 4
- 229920002401 polyacrylamide Polymers 0.000 claims description 4
- 235000002906 tartaric acid Nutrition 0.000 claims description 4
- 239000011975 tartaric acid Substances 0.000 claims description 4
- 239000004372 Polyvinyl alcohol Substances 0.000 claims description 3
- CETPSERCERDGAM-UHFFFAOYSA-N ceric oxide Chemical compound O=[Ce]=O CETPSERCERDGAM-UHFFFAOYSA-N 0.000 claims description 3
- 229910000422 cerium(IV) oxide Inorganic materials 0.000 claims description 3
- 229920002451 polyvinyl alcohol Polymers 0.000 claims description 3
- 229920000036 polyvinylpyrrolidone Polymers 0.000 claims description 3
- 239000001267 polyvinylpyrrolidone Substances 0.000 claims description 3
- 235000013855 polyvinylpyrrolidone Nutrition 0.000 claims description 3
- 229920005575 poly(amic acid) Polymers 0.000 claims description 2
- 239000010408 film Substances 0.000 description 97
- 239000010410 layer Substances 0.000 description 50
- 238000005530 etching Methods 0.000 description 12
- 229910052710 silicon Inorganic materials 0.000 description 11
- 239000010703 silicon Substances 0.000 description 11
- 230000015572 biosynthetic process Effects 0.000 description 10
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 description 9
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 9
- 230000000694 effects Effects 0.000 description 7
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 6
- 230000000052 comparative effect Effects 0.000 description 6
- -1 silicon alkoxide Chemical class 0.000 description 6
- 230000002776 aggregation Effects 0.000 description 5
- 150000003863 ammonium salts Chemical class 0.000 description 5
- 229910044991 metal oxide Inorganic materials 0.000 description 5
- 150000004706 metal oxides Chemical class 0.000 description 5
- 239000000243 solution Substances 0.000 description 5
- DHMQDGOQFOQNFH-UHFFFAOYSA-N Glycine Chemical compound NCC(O)=O DHMQDGOQFOQNFH-UHFFFAOYSA-N 0.000 description 4
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 4
- 238000004220 aggregation Methods 0.000 description 4
- 230000007062 hydrolysis Effects 0.000 description 4
- 238000006460 hydrolysis reaction Methods 0.000 description 4
- 239000011229 interlayer Substances 0.000 description 4
- 230000002829 reductive effect Effects 0.000 description 4
- 239000004065 semiconductor Substances 0.000 description 4
- 239000002904 solvent Substances 0.000 description 4
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 description 3
- NLXLAEXVIDQMFP-UHFFFAOYSA-N Ammonia chloride Chemical compound [NH4+].[Cl-] NLXLAEXVIDQMFP-UHFFFAOYSA-N 0.000 description 3
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 3
- MUBZPKHOEPUJKR-UHFFFAOYSA-N Oxalic acid Chemical compound OC(=O)C(O)=O MUBZPKHOEPUJKR-UHFFFAOYSA-N 0.000 description 3
- CBENFWSGALASAD-UHFFFAOYSA-N Ozone Chemical compound [O-][O+]=O CBENFWSGALASAD-UHFFFAOYSA-N 0.000 description 3
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 3
- 229910021529 ammonia Inorganic materials 0.000 description 3
- 235000015165 citric acid Nutrition 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 238000002156 mixing Methods 0.000 description 3
- 229910017604 nitric acid Inorganic materials 0.000 description 3
- 230000008569 process Effects 0.000 description 3
- MLIWQXBKMZNZNF-KUHOPJCQSA-N (2e)-2,6-bis[(4-azidophenyl)methylidene]-4-methylcyclohexan-1-one Chemical compound O=C1\C(=C\C=2C=CC(=CC=2)N=[N+]=[N-])CC(C)CC1=CC1=CC=C(N=[N+]=[N-])C=C1 MLIWQXBKMZNZNF-KUHOPJCQSA-N 0.000 description 2
- YTZPUTADNGREHA-UHFFFAOYSA-N 2h-benzo[e]benzotriazole Chemical compound C1=CC2=CC=CC=C2C2=NNN=C21 YTZPUTADNGREHA-UHFFFAOYSA-N 0.000 description 2
- 239000004115 Sodium Silicate Substances 0.000 description 2
- BOTDANWDWHJENH-UHFFFAOYSA-N Tetraethyl orthosilicate Chemical compound CCO[Si](OCC)(OCC)OCC BOTDANWDWHJENH-UHFFFAOYSA-N 0.000 description 2
- NRTOMJZYCJJWKI-UHFFFAOYSA-N Titanium nitride Chemical compound [Ti]#N NRTOMJZYCJJWKI-UHFFFAOYSA-N 0.000 description 2
- WNLRTRBMVRJNCN-UHFFFAOYSA-N adipic acid Chemical compound OC(=O)CCCCC(O)=O WNLRTRBMVRJNCN-UHFFFAOYSA-N 0.000 description 2
- 229910052783 alkali metal Inorganic materials 0.000 description 2
- 150000001340 alkali metals Chemical class 0.000 description 2
- 229910052784 alkaline earth metal Inorganic materials 0.000 description 2
- 150000001342 alkaline earth metals Chemical class 0.000 description 2
- ROOXNKNUYICQNP-UHFFFAOYSA-N ammonium persulfate Chemical compound [NH4+].[NH4+].[O-]S(=O)(=O)OOS([O-])(=O)=O ROOXNKNUYICQNP-UHFFFAOYSA-N 0.000 description 2
- WPYMKLBDIGXBTP-UHFFFAOYSA-N benzoic acid Chemical compound OC(=O)C1=CC=CC=C1 WPYMKLBDIGXBTP-UHFFFAOYSA-N 0.000 description 2
- 125000003178 carboxy group Chemical group [H]OC(*)=O 0.000 description 2
- 238000011109 contamination Methods 0.000 description 2
- 238000005260 corrosion Methods 0.000 description 2
- 230000007797 corrosion Effects 0.000 description 2
- XBDQKXXYIPTUBI-UHFFFAOYSA-N dimethylselenoniopropionate Natural products CCC(O)=O XBDQKXXYIPTUBI-UHFFFAOYSA-N 0.000 description 2
- 238000011156 evaluation Methods 0.000 description 2
- 239000011521 glass Substances 0.000 description 2
- 229960002449 glycine Drugs 0.000 description 2
- 150000004820 halides Chemical class 0.000 description 2
- MNWFXJYAOYHMED-UHFFFAOYSA-N heptanoic acid Chemical compound CCCCCCC(O)=O MNWFXJYAOYHMED-UHFFFAOYSA-N 0.000 description 2
- FUZZWVXGSFPDMH-UHFFFAOYSA-N hexanoic acid Chemical compound CCCCCC(O)=O FUZZWVXGSFPDMH-UHFFFAOYSA-N 0.000 description 2
- QWPPOHNGKGFGJK-UHFFFAOYSA-N hypochlorous acid Chemical compound ClO QWPPOHNGKGFGJK-UHFFFAOYSA-N 0.000 description 2
- 238000009413 insulation Methods 0.000 description 2
- FGKJLKRYENPLQH-UHFFFAOYSA-N isocaproic acid Chemical compound CC(C)CCC(O)=O FGKJLKRYENPLQH-UHFFFAOYSA-N 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- BDAGIHXWWSANSR-UHFFFAOYSA-N methanoic acid Natural products OC=O BDAGIHXWWSANSR-UHFFFAOYSA-N 0.000 description 2
- 125000002496 methyl group Chemical group [H]C([H])([H])* 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 239000000178 monomer Substances 0.000 description 2
- WWZKQHOCKIZLMA-UHFFFAOYSA-N octanoic acid Chemical compound CCCCCCCC(O)=O WWZKQHOCKIZLMA-UHFFFAOYSA-N 0.000 description 2
- 235000005985 organic acids Nutrition 0.000 description 2
- WLJVNTCWHIRURA-UHFFFAOYSA-N pimelic acid Chemical compound OC(=O)CCCCCC(O)=O WLJVNTCWHIRURA-UHFFFAOYSA-N 0.000 description 2
- 229920000642 polymer Polymers 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- YGSDEFSMJLZEOE-UHFFFAOYSA-N salicylic acid Chemical compound OC(=O)C1=CC=CC=C1O YGSDEFSMJLZEOE-UHFFFAOYSA-N 0.000 description 2
- 238000007790 scraping Methods 0.000 description 2
- 159000000000 sodium salts Chemical class 0.000 description 2
- NTHWMYGWWRZVTN-UHFFFAOYSA-N sodium silicate Chemical compound [Na+].[Na+].[O-][Si]([O-])=O NTHWMYGWWRZVTN-UHFFFAOYSA-N 0.000 description 2
- 229910052911 sodium silicate Inorganic materials 0.000 description 2
- 238000004544 sputter deposition Methods 0.000 description 2
- 239000010409 thin film Substances 0.000 description 2
- NQPDZGIKBAWPEJ-UHFFFAOYSA-N valeric acid Chemical compound CCCCC(O)=O NQPDZGIKBAWPEJ-UHFFFAOYSA-N 0.000 description 2
- OBETXYAYXDNJHR-SSDOTTSWSA-M (2r)-2-ethylhexanoate Chemical compound CCCC[C@@H](CC)C([O-])=O OBETXYAYXDNJHR-SSDOTTSWSA-M 0.000 description 1
- BNGXYYYYKUGPPF-UHFFFAOYSA-M (3-methylphenyl)methyl-triphenylphosphanium;chloride Chemical compound [Cl-].CC1=CC=CC(C[P+](C=2C=CC=CC=2)(C=2C=CC=CC=2)C=2C=CC=CC=2)=C1 BNGXYYYYKUGPPF-UHFFFAOYSA-M 0.000 description 1
- RBNPOMFGQQGHHO-UHFFFAOYSA-N -2,3-Dihydroxypropanoic acid Natural products OCC(O)C(O)=O RBNPOMFGQQGHHO-UHFFFAOYSA-N 0.000 description 1
- RTBFRGCFXZNCOE-UHFFFAOYSA-N 1-methylsulfonylpiperidin-4-one Chemical compound CS(=O)(=O)N1CCC(=O)CC1 RTBFRGCFXZNCOE-UHFFFAOYSA-N 0.000 description 1
- PAWQVTBBRAZDMG-UHFFFAOYSA-N 2-(3-bromo-2-fluorophenyl)acetic acid Chemical compound OC(=O)CC1=CC=CC(Br)=C1F PAWQVTBBRAZDMG-UHFFFAOYSA-N 0.000 description 1
- OXQGTIUCKGYOAA-UHFFFAOYSA-N 2-Ethylbutanoic acid Chemical compound CCC(CC)C(O)=O OXQGTIUCKGYOAA-UHFFFAOYSA-N 0.000 description 1
- WLAMNBDJUVNPJU-UHFFFAOYSA-N 2-methylbutyric acid Chemical compound CCC(C)C(O)=O WLAMNBDJUVNPJU-UHFFFAOYSA-N 0.000 description 1
- CVKMFSAVYPAZTQ-UHFFFAOYSA-N 2-methylhexanoic acid Chemical compound CCCCC(C)C(O)=O CVKMFSAVYPAZTQ-UHFFFAOYSA-N 0.000 description 1
- KFJDQPJLANOOOB-UHFFFAOYSA-N 2h-benzotriazole-4-carboxylic acid Chemical compound OC(=O)C1=CC=CC2=NNN=C12 KFJDQPJLANOOOB-UHFFFAOYSA-N 0.000 description 1
- MLMQPDHYNJCQAO-UHFFFAOYSA-N 3,3-dimethylbutyric acid Chemical compound CC(C)(C)CC(O)=O MLMQPDHYNJCQAO-UHFFFAOYSA-N 0.000 description 1
- OSWFIVFLDKOXQC-UHFFFAOYSA-N 4-(3-methoxyphenyl)aniline Chemical compound COC1=CC=CC(C=2C=CC(N)=CC=2)=C1 OSWFIVFLDKOXQC-UHFFFAOYSA-N 0.000 description 1
- CMGDVUCDZOBDNL-UHFFFAOYSA-N 4-methyl-2h-benzotriazole Chemical compound CC1=CC=CC2=NNN=C12 CMGDVUCDZOBDNL-UHFFFAOYSA-N 0.000 description 1
- 229910000838 Al alloy Inorganic materials 0.000 description 1
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 description 1
- 239000005711 Benzoic acid Substances 0.000 description 1
- RBNPOMFGQQGHHO-UWTATZPHSA-N D-glyceric acid Chemical compound OC[C@@H](O)C(O)=O RBNPOMFGQQGHHO-UWTATZPHSA-N 0.000 description 1
- 239000004471 Glycine Substances 0.000 description 1
- 239000004793 Polystyrene Substances 0.000 description 1
- KDYFGRWQOYBRFD-UHFFFAOYSA-N Succinic acid Natural products OC(=O)CCC(O)=O KDYFGRWQOYBRFD-UHFFFAOYSA-N 0.000 description 1
- 235000011054 acetic acid Nutrition 0.000 description 1
- 239000001361 adipic acid Substances 0.000 description 1
- 235000011037 adipic acid Nutrition 0.000 description 1
- 238000005054 agglomeration Methods 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- OBETXYAYXDNJHR-UHFFFAOYSA-N alpha-ethylcaproic acid Natural products CCCCC(CC)C(O)=O OBETXYAYXDNJHR-UHFFFAOYSA-N 0.000 description 1
- 150000001408 amides Chemical class 0.000 description 1
- 235000019270 ammonium chloride Nutrition 0.000 description 1
- 235000011114 ammonium hydroxide Nutrition 0.000 description 1
- 229910001870 ammonium persulfate Inorganic materials 0.000 description 1
- JFCQEDHGNNZCLN-UHFFFAOYSA-N anhydrous glutaric acid Natural products OC(=O)CCCC(O)=O JFCQEDHGNNZCLN-UHFFFAOYSA-N 0.000 description 1
- 150000001450 anions Chemical class 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 235000010233 benzoic acid Nutrition 0.000 description 1
- 125000003354 benzotriazolyl group Chemical group N1N=NC2=C1C=CC=C2* 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- KDYFGRWQOYBRFD-NUQCWPJISA-N butanedioic acid Chemical compound O[14C](=O)CC[14C](O)=O KDYFGRWQOYBRFD-NUQCWPJISA-N 0.000 description 1
- 125000000484 butyl group Chemical group [H]C([*])([H])C([H])([H])C([H])([H])C([H])([H])[H] 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- KRVSOGSZCMJSLX-UHFFFAOYSA-L chromic acid Substances O[Cr](O)(=O)=O KRVSOGSZCMJSLX-UHFFFAOYSA-L 0.000 description 1
- 230000002301 combined effect Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000000994 depressogenic effect Effects 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 238000010494 dissociation reaction Methods 0.000 description 1
- 230000005593 dissociations Effects 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 238000001312 dry etching Methods 0.000 description 1
- 125000001495 ethyl group Chemical group [H]C([H])([H])C([H])([H])* 0.000 description 1
- 239000006260 foam Substances 0.000 description 1
- 235000019253 formic acid Nutrition 0.000 description 1
- AWJWCTOOIBYHON-UHFFFAOYSA-N furo[3,4-b]pyrazine-5,7-dione Chemical compound C1=CN=C2C(=O)OC(=O)C2=N1 AWJWCTOOIBYHON-UHFFFAOYSA-N 0.000 description 1
- 238000007429 general method Methods 0.000 description 1
- 235000013905 glycine and its sodium salt Nutrition 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 125000004435 hydrogen atom Chemical group [H]* 0.000 description 1
- 230000001771 impaired effect Effects 0.000 description 1
- 230000002401 inhibitory effect Effects 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- 238000005342 ion exchange Methods 0.000 description 1
- VZCYOOQTPOCHFL-UPHRSURJSA-N maleic acid Chemical compound OC(=O)\C=C/C(O)=O VZCYOOQTPOCHFL-UPHRSURJSA-N 0.000 description 1
- 239000011976 maleic acid Substances 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 125000002347 octyl group Chemical group [H]C([*])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])[H] 0.000 description 1
- 235000006408 oxalic acid Nutrition 0.000 description 1
- BPUBBGLMJRNUCC-UHFFFAOYSA-N oxygen(2-);tantalum(5+) Chemical class [O-2].[O-2].[O-2].[O-2].[O-2].[Ta+5].[Ta+5] BPUBBGLMJRNUCC-UHFFFAOYSA-N 0.000 description 1
- FJKROLUGYXJWQN-UHFFFAOYSA-N papa-hydroxy-benzoic acid Natural products OC(=O)C1=CC=C(O)C=C1 FJKROLUGYXJWQN-UHFFFAOYSA-N 0.000 description 1
- 125000001997 phenyl group Chemical group [H]C1=C([H])C([H])=C(*)C([H])=C1[H] 0.000 description 1
- XNGIFLGASWRNHJ-UHFFFAOYSA-N phthalic acid Chemical class OC(=O)C1=CC=CC=C1C(O)=O XNGIFLGASWRNHJ-UHFFFAOYSA-N 0.000 description 1
- 238000007517 polishing process Methods 0.000 description 1
- 229920002223 polystyrene Polymers 0.000 description 1
- 229920005749 polyurethane resin Polymers 0.000 description 1
- 229920000915 polyvinyl chloride Polymers 0.000 description 1
- 239000004800 polyvinyl chloride Substances 0.000 description 1
- 235000019260 propionic acid Nutrition 0.000 description 1
- 125000001436 propyl group Chemical group [H]C([*])([H])C([H])([H])C([H])([H])[H] 0.000 description 1
- IUVKMZGDUIUOCP-BTNSXGMBSA-N quinbolone Chemical compound O([C@H]1CC[C@H]2[C@H]3[C@@H]([C@]4(C=CC(=O)C=C4CC3)C)CC[C@@]21C)C1=CCCC1 IUVKMZGDUIUOCP-BTNSXGMBSA-N 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 229960004889 salicylic acid Drugs 0.000 description 1
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 description 1
- 229910010271 silicon carbide Inorganic materials 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 230000001629 suppression Effects 0.000 description 1
- UAXOELSVPTZZQG-UHFFFAOYSA-N tiglic acid Natural products CC(C)=C(C)C(O)=O UAXOELSVPTZZQG-UHFFFAOYSA-N 0.000 description 1
- VZCYOOQTPOCHFL-UHFFFAOYSA-N trans-butenedioic acid Natural products OC(=O)C=CC(O)=O VZCYOOQTPOCHFL-UHFFFAOYSA-N 0.000 description 1
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 1
- 229910052721 tungsten Inorganic materials 0.000 description 1
- 239000010937 tungsten Substances 0.000 description 1
- 229940005605 valeric acid Drugs 0.000 description 1
- 125000000391 vinyl group Chemical group [H]C([*])=C([H])[H] 0.000 description 1
Landscapes
- Finish Polishing, Edge Sharpening, And Grinding By Specific Grinding Devices (AREA)
- Mechanical Treatment Of Semiconductor (AREA)
Description
本発明は、特に半導体デバイスの配線形成工程の研磨に使用される導体用研磨液及びこれを用いた研磨方法に関する。 The present invention relates to a conductor polishing liquid used for polishing a wiring formation process of a semiconductor device, and a polishing method using the same.
近年、半導体集積回路（以下ＬＳＩと記す）の高集積化、高性能化に伴って新たな微細加工技術が開発されている。化学機械研磨（以下ＣＭＰと記す）法もその一つであり、ＬＳＩ製造工程、特に多層配線形成工程における層間絶縁膜の平坦化、金属プラグ形成、埋め込み配線形成において頻繁に利用される技術である。この技術は、例えば特許文献１に開示されている。 In recent years, new microfabrication techniques have been developed along with higher integration and higher performance of semiconductor integrated circuits (hereinafter referred to as LSIs). The chemical mechanical polishing (hereinafter referred to as CMP) method is one of them, and is a technique frequently used in the LSI manufacturing process, particularly in the multilayer wiring formation process, planarization of the interlayer insulating film, metal plug formation, and buried wiring formation. . This technique is disclosed in Patent Document 1, for example.
また、最近はＬＳＩを高性能化するために、配線材料として銅及び銅合金の利用が試みられている。しかし、銅及び銅合金は従来のアルミニウム合金配線の形成で頻繁に用いられたドライエッチング法による微細加工が困難である。そこで、あらかじめ溝を形成してある絶縁膜上に銅又は銅合金薄膜を堆積して埋め込み、溝部以外の銅又は銅合金薄膜をＣＭＰにより除去して埋め込み配線を形成する、いわゆるダマシン法が主に採用されている。この技術は、例えば特許文献２に開示されている。 Recently, in order to improve the performance of LSIs, attempts have been made to use copper and copper alloys as wiring materials. However, copper and copper alloys are difficult to finely process by the dry etching method frequently used in the formation of conventional aluminum alloy wiring. Therefore, a so-called damascene method is mainly used, in which a copper or copper alloy thin film is deposited and embedded on an insulating film in which a groove is formed in advance, and the copper or copper alloy thin film other than the groove is removed by CMP to form a buried wiring. It has been adopted. This technique is disclosed in Patent Document 2, for example.
銅及び銅合金等の金属ＣＭＰの一般的な方法は、円形の研磨定盤（プラテン）上に研磨パッドを貼り付け、研磨パッド表面を金属用研磨液で浸し、基板の金属膜を形成した面を押し付けて、その裏面から所定の圧力（以下研磨圧力と記す）を加えた状態で研磨定盤を回し、研磨液と金属膜の凸部との機械的摩擦によって凸部の金属膜を除去するものである。
ＣＭＰに用いられる金属用研磨液は、一般には酸化剤及び砥粒からなっており必要に応じてさらに酸化金属溶解剤、保護膜形成剤が添加される。まず酸化剤によって金属膜表面を酸化し、その酸化層を砥粒によって削り取るのが基本的なメカニズムと考えられている。凹部の金属表面の酸化層は研磨パッドにあまり触れず、砥粒による削り取りの効果が及ばないので、ＣＭＰの進行とともに凸部の金属層が除去されて基板表面は平坦化される。この詳細については非特許文献１に開示されている。
A general method of metal CMP such as copper and copper alloy is a surface on which a polishing pad is attached on a circular polishing platen (platen), the surface of the polishing pad is immersed in a metal polishing liquid, and a metal film of a substrate is formed. Is pressed and a polishing surface plate is rotated with a predetermined pressure (hereinafter referred to as polishing pressure) applied from the back surface, and the metal film on the convex portion is removed by mechanical friction between the polishing liquid and the convex portion of the metal film. Is.
The metal polishing liquid used in CMP is generally composed of an oxidizing agent and abrasive grains, and a metal oxide dissolving agent and a protective film forming agent are further added as necessary. First, it is considered that the basic mechanism is to oxidize the surface of a metal film with an oxidizing agent and scrape the oxidized layer with abrasive grains. Since the oxide layer on the metal surface of the recess does not touch the polishing pad so much and the effect of scraping off by the abrasive grains does not reach, the metal layer of the projection is removed and the substrate surface is flattened with the progress of CMP. This detail is disclosed in Non-Patent Document 1.
ＣＭＰによる研磨速度を高める方法として酸化金属溶解剤を添加することが有効とされている。砥粒によって削り取られた金属酸化物の粒を研磨液に溶解（以下エッチングと記す）させてしまうと砥粒による削り取りの効果が増すためであるためと解釈できる。酸化金属溶解剤の添加によりＣＭＰによる研磨速度は向上するが、一方、凹部の金属膜表面の酸化層もエッチング（溶解）されて金属膜表面が露出すると、酸化剤によって金属膜表面がさらに酸化され、これが繰り返されると凹部の金属膜のエッチングが進行してしまう。このため研磨後に埋め込まれた金属配線の表面中央部分が皿のように窪む現象（以下、ディッシングと記す。）が発生し、平坦化効果が損なわれる。 As a method for increasing the polishing rate by CMP, it is effective to add a metal oxide dissolving agent. It can be interpreted that if the metal oxide particles scraped by the abrasive grains are dissolved in the polishing liquid (hereinafter referred to as etching), the effect of scraping by the abrasive grains is increased. Although the polishing rate by CMP is improved by adding a metal oxide solubilizer, on the other hand, when the oxide layer on the metal film surface in the recess is also etched (dissolved) and the metal film surface is exposed, the metal film surface is further oxidized by the oxidant. If this is repeated, etching of the metal film in the recesses proceeds. For this reason, a phenomenon occurs in which the central portion of the surface of the metal wiring embedded after polishing is depressed like a dish (hereinafter referred to as dishing), and the planarization effect is impaired.
これを防ぐためにさらに保護膜形成剤が添加される。保護膜形成剤は金属膜表面の酸化層上に保護膜を形成し、酸化層の研磨液中への溶解を防止するものである。この保護膜は砥粒により容易に削り取ることが可能で、ＣＭＰによる研磨速度を低下させないことが望まれる。
銅及び銅合金のディッシングや研磨中の腐食を抑制し、信頼性の高いＬＳＩ配線を形成するために、グリシン等のアミノ酢酸又はアミド硫酸からなる酸化金属溶解剤及び保護膜形成剤としてベンゾトリアゾール（ＢＴＡ）を含有する金属用研磨液を用いる方法が提唱されている。この技術は、例えば特許文献３に記載されている。
In order to prevent this, a protective film forming agent is further added. The protective film forming agent forms a protective film on the oxide layer on the surface of the metal film and prevents dissolution of the oxide layer in the polishing liquid. This protective film can be easily scraped off by abrasive grains, and it is desirable not to reduce the polishing rate by CMP.
In order to suppress corrosion during dishing and polishing of copper and copper alloys, and to form highly reliable LSI wiring, benzotriazole (as metal oxide solubilizer and protective film forming agent consisting of aminoacetic acid or amide sulfuric acid such as glycine) A method using a metal polishing liquid containing BTA) has been proposed. This technique is described in Patent Document 3, for example.
銅及び銅合金のダマシン配線形成やタングステン等のプラグ配線形成等の金属埋め込み形成においては、埋め込み部分以外に形成される層間絶縁膜である二酸化シリコン膜の研磨速度も大きい場合には、層間絶縁膜ごと配線の厚みが薄くなるシニングが発生する。その結果、配線抵抗の増加やパターン密度等により抵抗のばらつきが生じるために、研磨される金属膜に対して二酸化シリコン膜の研磨速度が十分小さい特性が要求される。そこで、酸の解離により生ずる陰イオンにより二酸化シリコンの研磨速度を抑制することにより、研磨液のｐＨをｐＫａ−０．５よりも大きくする方法が提唱されている。この技術は、例えば特許文献４に記載されている。 In metal buried formation such as damascene wiring formation of copper and copper alloy and plug wiring formation of tungsten etc., when the polishing rate of the silicon dioxide film which is an interlayer insulation film formed other than the buried portion is high, the interlayer insulation film Thinning in which the thickness of each wiring is reduced occurs. As a result, resistance variation occurs due to an increase in wiring resistance, pattern density, and the like, so that a characteristic in which the polishing rate of the silicon dioxide film is sufficiently small with respect to the metal film to be polished is required. Accordingly, a method has been proposed in which the polishing rate of silicon dioxide is suppressed by anions generated by acid dissociation so that the polishing solution has a pH higher than pKa-0.5. This technique is described in Patent Document 4, for example.
一方、配線の銅又は銅合金等の下層には、層間絶縁膜中への銅拡散防止のためにバリア層として、タンタルやタンタル合金及び窒化タンタルやその他のタンタル化合物等が形成される。したがって、銅又は銅合金を埋め込む配線部分以外では、露出したバリア層をＣＭＰにより取り除く必要がある。しかし、これらのバリア層は、銅又は銅合金に比べ硬度が高いために、銅又は銅合金用の研磨材料の組み合わせでは十分な研磨速度が得られない場合が多い。そこで、銅又は銅合金を研磨する第１工程と、バリア層となる導体を研磨する第２工程からなる２段研磨方法が検討されている。 On the other hand, tantalum, a tantalum alloy, tantalum nitride, other tantalum compounds, and the like are formed as a barrier layer to prevent copper diffusion into the interlayer insulating film in a lower layer such as copper or copper alloy of the wiring. Therefore, it is necessary to remove the exposed barrier layer by CMP except for the wiring portion in which copper or a copper alloy is embedded. However, since these barrier layers have higher hardness than copper or copper alloys, a combination of polishing materials for copper or copper alloys cannot often provide a sufficient polishing rate. Therefore, a two-stage polishing method is being studied that includes a first step of polishing copper or a copper alloy and a second step of polishing a conductor serving as a barrier layer.
第２工程であるバリア層となる導体のＣＭＰでは、銅及び銅合金埋め込み配線部のディッシングを防止する必要があり、銅又は銅合金の研磨速度及びエッチング速度を抑制するために、研磨液のｐＨを小さくすることはマイナス効果であると考えられていた。
バリア層として用いられるタンタルやタンタル合金及び窒化タンタルやその他のタンタル化合物は、化学的に安定でエッチングが難しく、硬度が高いために機械的な研磨も銅及び銅合金ほど容易ではない。そこで、砥粒の硬度を上げた場合には、銅又は銅合金に研磨キズが発生して電気特性不良の原因になったり、砥粒の粒子濃度を高くした場合には、二酸化シリコン膜の研磨速度が大きくなってしまいシニングが発生するという問題があった。
Tantalum, tantalum alloys, tantalum nitride, and other tantalum compounds used as barrier layers are chemically stable and difficult to etch, and have high hardness, so mechanical polishing is not as easy as copper and copper alloys. Therefore, if the hardness of the abrasive grains is increased, polishing scratches may occur in the copper or copper alloy, resulting in poor electrical characteristics, or if the abrasive grain concentration is increased, the silicon dioxide film is polished. There was a problem that the speed increased and thinning occurred.
本発明は、バリア層となる導体として用いられるタンタルやタンタル合金及び窒化タンタルやその他のタンタル化合物等を低砥粒濃度において高い研磨速度で研磨でき、かつ銅又は銅合金配線のディッシングとシニング及び研磨キズ発生を抑制でき、信頼性の高い金属膜の埋め込みパターン形成することができる導体用研磨液及びこれを用いた研磨方法を提供するものである。 The present invention is capable of polishing tantalum, tantalum alloy, tantalum nitride and other tantalum compounds used as a conductor serving as a barrier layer at a high polishing rate at a low abrasive concentration, and dishing, thinning and polishing of copper or copper alloy wiring. It is an object of the present invention to provide a conductive polishing liquid that can suppress generation of scratches and form a highly reliable embedded pattern of a metal film, and a polishing method using the same.
本発明者らは、バリア層となる導体として用いられるタンタルやタンタル合金及び窒化タンタルやその他のタンタル化合物の研磨において、砥粒粒径が大きすぎると、バリア層の研磨速度が低下してしまい、二酸化シリコンの研磨速度が増加してしまうことを見出した。更に、砥粒の平均粒径が小さくても、凝集していない一次粒子からなる砥粒であると二酸化シリコンの研磨速度が増加してしまうことを見出した。この現象は、低ｐＨ領域かつ低酸化剤濃度領域でタンタルやタンタル合金及び窒化タンタルやその他のタンタル化合物を研磨する際に顕著である。本発明はこれらの知見に基づいてなされたものである。 In the polishing of tantalum and tantalum alloys and tantalum nitride and other tantalum compounds used as conductors serving as a barrier layer, the inventors have reduced the polishing rate of the barrier layer if the abrasive grain size is too large, It has been found that the polishing rate of silicon dioxide increases. Furthermore, it has been found that even when the average grain size of the abrasive grains is small, the polishing rate of silicon dioxide increases if the abrasive grains are composed of primary particles that are not aggregated. This phenomenon is remarkable when polishing tantalum, a tantalum alloy, tantalum nitride, and other tantalum compounds in a low pH region and a low oxidizing agent concentration region. The present invention has been made based on these findings.
本発明は、砥粒、導体の酸化剤、金属表面に対する保護膜形成剤、酸及び水を含有する研磨液であり、砥粒が一次粒子が平均２〜３粒子凝集した平均粒径が６０ｎｍ以下の２次粒子からなる粒子であることを特徴とするバリア層研磨用研磨液（以下、導体用研磨液と呼ぶ。）に関する。 The present invention is a polishing liquid containing abrasive grains, a conductor oxidizer, a protective film-forming agent for metal surfaces, an acid and water, and the average particle diameter of abrasive grains aggregated from 2 to 3 primary particles is 60 nm. The present invention relates to a barrier layer polishing polishing liquid (hereinafter referred to as a conductor polishing liquid ), which is characterized by being composed of the following secondary particles.
砥粒の平均粒径は好ましくは５０ｎｍ以下であり、より好ましくは３０〜２０ｎｍである。また、この砥粒は、一次粒子が平均２〜３粒子凝集した２次粒子からなる粒子である。
砥粒は、シリカ、アルミナ、セリア、チタニア、ジルコニア及びゲルマニアより選ばれた少なくとも１種であることが好ましく、コロイダルシリカ又はコロイダルアルミナであることがより好ましい。コロイダルシリカは、シリコンアルコキシドの加水分解により製造したものが好ましいが、珪酸ナトリウムを原料として製造したものも使用できる。砥粒濃度は、０．０５〜３重量％であることが好ましい。
The average particle size of the abrasive grains is preferably 50 nm or less, more preferably 30 to 20 nm. Further, the abrasive grains are particles consisting of secondary particles in which primary particles are averaged 2-3 particle agglomeration.
The abrasive is preferably at least one selected from silica, alumina, ceria, titania, zirconia and germania, and more preferably colloidal silica or colloidal alumina. The colloidal silica is preferably one produced by hydrolysis of silicon alkoxide, but one produced using sodium silicate as a raw material can also be used. The abrasive concentration is preferably 0.05 to 3% by weight.
導体用研磨液のｐＨは３以下、かつ導体の酸化剤濃度が０．０１〜３重量％であることが好ましい。
導体用研磨液にはさらに水溶性高分子を含むことができ、その場合の導体の酸化剤濃度は、０．０１〜１．５重量％であることが好ましい。
導体用研磨剤をバリア層となる導体用に使用する場合は、導体の酸化剤の濃度は、０．０１〜１．５重量％であることが好ましい。
The conductor polishing liquid preferably has a pH of 3 or less and a conductor oxidizing agent concentration of 0.01 to 3% by weight.
The conductor polishing liquid may further contain a water-soluble polymer, and the oxidant concentration of the conductor in this case is preferably 0.01 to 1.5% by weight.
When the conductive abrasive is used for a conductor serving as a barrier layer, the concentration of the oxidant in the conductor is preferably 0.01 to 1.5% by weight.
水溶性高分子は、ポリアクリル酸もしくはその塩、ポリアクリルアミド、ポリメタクリル酸もしくはその塩、ポリアミド酸もしくはその塩、ポリアクリルアミド、ポリビニルアルコール及びポリビニルピロリドンからなる群から選ばれた少なくとも１種が好ましい。 The water-soluble polymer is preferably at least one selected from the group consisting of polyacrylic acid or a salt thereof, polyacrylamide, polymethacrylic acid or a salt thereof, polyamic acid or a salt thereof, polyacrylamide, polyvinyl alcohol, and polyvinylpyrrolidone.
酸は、有機酸であることが好ましく、マロン酸、リンゴ酸、酒石酸、グリコール酸及びクエン酸から選ばれた少なくとも１種であることがより好ましい。 The acid is preferably an organic acid, and more preferably at least one selected from malonic acid, malic acid, tartaric acid, glycolic acid and citric acid.
導体の酸化剤は、過酸化水素、硝酸、過ヨウ素酸カリウム、次亜塩素酸、オゾン水より選ばれた少なくとも１種であることが好ましい。 The conductor oxidizing agent is preferably at least one selected from hydrogen peroxide, nitric acid, potassium periodate, hypochlorous acid, and ozone water.
導体は、銅又は銅合金のバリア層となる導体であることが好ましく、銅又は銅合金のバリア層となる導体が、タンタル、窒化タンタル、タンタル合金、その他のタンタル化合物であることが好ましい。 The conductor is preferably a conductor serving as a copper or copper alloy barrier layer, and the conductor serving as a copper or copper alloy barrier layer is preferably tantalum, tantalum nitride, a tantalum alloy, or other tantalum compounds.
金属表面に対する保護膜形成剤は、銅又は銅合金等の金属導体の表面を腐食から保護するもので、従来から広く用いられてきたベンゾトリアゾール（ＢＴＡ）及びその誘導体から選ばれた少なくとも一種（ＢＴＡ類）が好ましく用いられる。 The protective film-forming agent for the metal surface protects the surface of a metal conductor such as copper or copper alloy from corrosion, and is at least one selected from benzotriazole (BTA) and its derivatives which have been widely used conventionally (BTA) Are preferably used.
本発明は、また、上記の導体用研磨液を用いて、タンタル、窒化タンタル、タンタル合金又はその他のタンタル化合物からなるバリア層を研磨する研磨方法に関する。 The present invention also relates to a polishing method for polishing a barrier layer made of tantalum, tantalum nitride, a tantalum alloy, or other tantalum compounds using the above-described conductor polishing liquid.
本発明は、また、上記の導体用研磨液を用いて、銅又は銅合金とそのバリア層を含む面を研磨する研磨方法に関する。 The present invention also relates to a polishing method for polishing a surface including copper or a copper alloy and a barrier layer thereof using the above-described conductor polishing liquid.
本発明では、平均粒径が６０ｎｍ以下、かつ一次粒子が平均２〜３粒子凝集した二次粒子からなる砥粒を含有し、研磨液を好ましくは低ｐＨ領域かつ低酸化剤濃度領域にすることにより、銅又は銅合金配線のディッシングとシニング及び研磨キズ発生を抑制し、低砥粒濃度においてバリア層の高い研磨速度を実現することができる。
バリア層を研磨する方法として、砥粒の硬度を上げた場合には、銅合金に研磨キズが発生して電気特性不良の原因になったり、砥粒の粒子濃度を高くした場合には、二酸化シリコン膜の研磨速度が大きくなりシニングが発生してしまうという問題があったが、本発明の研磨液を用いると、バリア層として用いられるタンタルやタンタル合金及び窒化タンタルやその他のタンタル化合物の研磨が低ｐＨ領域かつ低酸化剤濃度領域で容易に進行する。また、これらの研磨速度が最大になる砥粒濃度が低濃度領域に存在し、酸化剤濃度が低い場合に、一般に低ｐＨ領域で問題になる銅又は銅合金のエッチング速度の増加による配線のディッシングも問題とならず、砥粒濃度が低いためにシニングも少ない。
In the present invention, the abrasive contains secondary particles having an average particle size of 60 nm or less and primary particles aggregated on average 2 to 3 particles, and the polishing liquid is preferably in a low pH region and a low oxidant concentration region. Thus, dishing and thinning of copper or copper alloy wiring and generation of polishing scratches can be suppressed, and a high polishing rate of the barrier layer can be realized at a low abrasive concentration.
As a method of polishing the barrier layer, when the hardness of the abrasive grains is increased, polishing scratches are generated in the copper alloy, resulting in poor electrical characteristics, or when the abrasive grain concentration is increased, There was a problem that the polishing rate of the silicon film increased and thinning occurred, but when the polishing liquid of the present invention was used, polishing of tantalum, tantalum alloy, tantalum nitride, and other tantalum compounds used as a barrier layer was performed. It proceeds easily in a low pH region and a low oxidant concentration region. In addition, when the abrasive concentration at which the polishing rate is maximized exists in the low concentration region and the oxidant concentration is low, the dishing of the wiring due to the increase in the etching rate of copper or copper alloy which is generally a problem in the low pH region However, since the abrasive concentration is low, thinning is small.
本発明の導体用研磨液は、バリア層として用いられるタンタルやタンタル合金及び窒化タンタルやその他のタンタル化合物の研磨を可能にし、かつ銅合金配線のディッシングとシニング及び研磨キズ発生を抑制し、信頼性の高い金属膜の埋め込みパターン形成することができる。 The conductor polishing liquid of the present invention enables polishing of tantalum, tantalum alloy, tantalum nitride, and other tantalum compounds used as a barrier layer, and suppresses dishing and thinning of copper alloy wiring and generation of polishing scratches, thereby improving reliability. It is possible to form a buried pattern of a high metal film.
例えば、表面に二酸化シリコンの凹部を有する基板上にバリア層及び銅又は銅合金を含む導体膜を形成・充填したものを、まず、銅又は銅合金／バリア層の研磨速度比が十分大きい銅又は銅合金用の研磨液を用いてＣＭＰすると、基板の凸部のバリア層が表面に露出し、凹部に銅又は銅合金膜が残された所望の導体パターンが得られる。本発明の導体用研磨液は、砥粒、導体の酸化剤、金属表面に対する保護膜形成剤、酸及び水を含有する研磨液であり、砥粒は平均粒径が６０ｎｍ以下かつ一次粒子が平均２〜３粒子凝集した二次粒子からなるものである。平均粒径が６０ｎｍより大きいとバリア層の研磨速度が小さく、二酸化シリコン膜の研磨速度が大きい。また、平均粒径が６０ｎｍ以下であっても、一次粒子が平均２粒子以上凝集していない粒子であると二酸化シリコン膜の研磨速度が大きくなる。また、一次粒子が平均１０粒子を超えて凝集して、平均粒径が７０ｎｍ以下になる粒子は製造が困難である。 For example, when a barrier layer and a conductor film containing copper or a copper alloy are formed and filled on a substrate having a silicon dioxide recess on the surface, the copper or copper alloy / barrier layer has a sufficiently high polishing rate ratio. When CMP is performed using a polishing liquid for copper alloy, a desired conductor pattern is obtained in which the barrier layer of the convex portion of the substrate is exposed on the surface and the copper or copper alloy film is left in the concave portion. The conductor polishing liquid of the present invention is a polishing liquid containing abrasive grains, a conductor oxidizing agent, a protective film forming agent for metal surfaces, an acid and water. The abrasive grains have an average particle size of 60 nm or less and primary particles. It consists of secondary particles aggregated on average 2 to 3 particles. When the average particle size is larger than 60 nm, the polishing rate of the barrier layer is low, and the polishing rate of the silicon dioxide film is high. Even if the average particle size is 60 nm or less, the polishing rate of the silicon dioxide film increases if the primary particles are particles that are not aggregated by two or more average particles. Moreover, it is difficult to produce particles in which the primary particles are aggregated exceeding an average of 10 particles and the average particle size is 70 nm or less.
本発明の砥粒の平均粒径は、光回折散乱式粒度分布計（例えば、COULTER Electronics社製の COULTER N４SD）を用いて、測定温度２０℃でｉｎｔｅｎｓｉｔｙ（散乱強度、濁度に相当）が５Ｅ＋０４〜４Ｅ＋０５の範囲になるように調整して（強度が強すぎる場合には純水で希釈して）５回測定し、Ｕｎｉｍｏｄａｌ値の平均値を求めた。なお、溶媒屈折率：１．３３３（水）、粒子屈折率：ｕｎｋｎｏｗｎ（という設定）、溶媒粘度：１．００５ｃｐ（水）、Ｒｕｎ Ｔｉｍｅ：２００ｓｅｃ、レーザー入射角：９０°で行った。
また、粒子の凝集度は、透過型電子顕微鏡（例えば（株）日立製作所製のH-７１００FA）を用いて、研磨液をミクロメッシュ上で凝集が発生しないように乾燥させて１０〜５０万倍で測定した。凝集度は２次粒子の２００個の凝集粒子数を観察して平均値を求めた。
The average particle size of the abrasive grains of the present invention is 5E + 04 with intensity (equivalent to scattering intensity and turbidity) at a measurement temperature of 20 ° C. using a light diffraction scattering type particle size distribution analyzer (for example, COULTER N4SD manufactured by COULTER Electronics). Adjustment was made to be in a range of ˜4E + 05 (diluted with pure water when the strength was too strong), and measurement was performed 5 times to obtain an average value of Unimodal values. The solvent refractive index was 1.333 (water), the particle refractive index was unknown (setting), the solvent viscosity was 1.005 cp (water), the run time was 200 sec, and the laser incident angle was 90 °.
Further, the degree of particle aggregation is 100 to 500,000 times by using a transmission electron microscope (for example, H-7100FA manufactured by Hitachi, Ltd.) to dry the polishing liquid so that no aggregation occurs on the micromesh. Measured with The degree of aggregation was determined by observing the number of 200 aggregated particles of secondary particles and calculating the average value.
導体用研磨液のｐＨは、３より大きいとタンタルやタンタル合金及び窒化タンタルやその他のタンタル化合物の研磨速度が小さくなる傾向がある。ｐＨは酸の添加量により調整することができる。またアンモニア、水酸化ナトリウム、テトラメチルアンモニウムハイドライド等のアルカリ成分の添加によっても調整可能である。 If the pH of the polishing slurry for conductors is greater than 3, the polishing rate of tantalum, tantalum alloy, tantalum nitride, and other tantalum compounds tends to be low. The pH can be adjusted by the amount of acid added. It can also be adjusted by adding alkali components such as ammonia, sodium hydroxide, tetramethylammonium hydride.
一方、本発明における導体用研磨液は、導体の酸化剤の濃度が０．１５重量％付近でタンタルやタンタル合金及び窒化タンタルやその他のタンタル化合物の研磨速度が極大になる。導体の酸化剤によりタンタルやタンタル合金及び窒化タンタルやその他のタンタル化合物等の導体膜表面に、機械的に研磨されやすい一次酸化層が形成され、高い研磨速度が得られる。一般にｐＨが３以下の場合には、銅又は銅合金膜のエッチング速度が大きく、金属表面に対する保護膜形成剤でのエッチング抑制は困難である。しかし、本発明では、導体の酸化剤の濃度を十分低くすると、金属表面に対する保護膜形成剤によるエッチング抑制が可能である。導体の酸化剤の濃度が３重量％より大きいと、銅又は銅合金のエッチング速度が大きくなりディッシング等が発生し易くなるだけでなく、タンタルやタンタル合金及び窒化タンタルやその他のタンタル化合物等の導体膜表面に、一次酸化層よりも研磨されにくい二次酸化層が形成されるために研磨速度が低下する傾向がある。酸化剤の濃度が０．０１重量％よりも小さいと、酸化層が充分形成されないために研磨速度が小さくなり、タンタル膜等の剥離等が発生することもある。 On the other hand, the polishing slurry for conductors in the present invention maximizes the polishing rate of tantalum, tantalum alloy, tantalum nitride, and other tantalum compounds when the concentration of the oxidant of the conductor is around 0.15% by weight. A primary oxide layer that is easily mechanically polished is formed on the surface of the conductor film such as tantalum, tantalum alloy, tantalum nitride, and other tantalum compounds by the conductor oxidizing agent, and a high polishing rate can be obtained. In general, when the pH is 3 or less, the etching rate of the copper or copper alloy film is high, and it is difficult to suppress the etching with a protective film forming agent on the metal surface. However, in the present invention, when the concentration of the oxidant in the conductor is sufficiently low, the etching with the protective film forming agent on the metal surface can be suppressed. If the concentration of the oxidant in the conductor is greater than 3% by weight, the etching rate of copper or copper alloy increases and dishing is likely to occur. Conductors such as tantalum, tantalum alloy, tantalum nitride, and other tantalum compounds Since a secondary oxide layer that is harder to polish than the primary oxide layer is formed on the film surface, the polishing rate tends to decrease. When the concentration of the oxidizing agent is less than 0.01% by weight, the oxide layer is not sufficiently formed, so that the polishing rate becomes low and peeling of the tantalum film or the like may occur.
本発明における導体用研磨液の導体の酸化剤は、水溶性高分子を含有する場合には、濃度が０．０１〜１．５重量％であることが好ましい。水溶性高分子は、タンタルやタンタル合金及び窒化タンタルやその他のタンタル化合物、又はその酸化膜表面に吸着するために、高い研磨速度が得られる酸化剤濃度範囲が小さくなる。また、水溶性高分子は、特に窒化タンタル膜や窒化チタン等の窒化化合物膜の表面に吸着し易いために、窒化タンタル膜や窒化チタン等の窒化化合物膜の研磨速度が小さくなる。一方、水溶性高分子は、金属の表面保護膜形成効果を持ち、ディッシングやシニング等の平坦化特性を向上させる。 In the present invention, when the conductor oxidizing agent of the conductor polishing liquid contains a water-soluble polymer, the concentration is preferably 0.01 to 1.5% by weight. The water-soluble polymer is adsorbed on the surface of tantalum, tantalum alloy, tantalum nitride, other tantalum compounds, or oxide films thereof, so that the oxidant concentration range in which a high polishing rate can be obtained is reduced. In addition, since the water-soluble polymer is easily adsorbed on the surface of a nitride compound film such as a tantalum nitride film or titanium nitride, the polishing rate of the nitride compound film such as a tantalum nitride film or titanium nitride is reduced. On the other hand, the water-soluble polymer has an effect of forming a metal surface protective film and improves planarization characteristics such as dishing and thinning.
本発明における導体の酸化剤としては、過酸化水素（Ｈ2Ｏ2）、硝酸、過ヨウ素酸カリウム、次亜塩素酸、オゾン水等が挙げられ、その中でも過酸化水素が特に好ましい。基板が集積回路用素子を含むシリコン基板である場合、アルカリ金属、アルカリ土類金属、ハロゲン化物などによる汚染は望ましくないので、不揮発成分を含まない酸化剤が望ましい。但し、オゾン水は組成の時間変化が激しいので過酸化水素が最も適している。但し、適用対象の基板が半導体素子を含まないガラス基板などである場合は不揮発成分を含む酸化剤であっても差し支えない。 Examples of the oxidant for the conductor in the present invention include hydrogen peroxide (H 2 O 2 ), nitric acid, potassium periodate, hypochlorous acid, ozone water, etc. Among them, hydrogen peroxide is particularly preferable. When the substrate is a silicon substrate including an integrated circuit element, contamination by alkali metal, alkaline earth metal, halide, or the like is not desirable, and thus an oxidizing agent that does not include a nonvolatile component is desirable. However, hydrogen peroxide is most suitable because ozone water has a severe compositional change over time. However, in the case where the substrate to be applied is a glass substrate that does not include a semiconductor element, an oxidizing agent that includes a nonvolatile component may be used.
本発明における酸としては、ギ酸、酢酸、プロピオン酸、吉草酸、２−メチル酪酸、ｎ−ヘキサン酸、３，３−ジメチル酪酸、２−エチル酪酸、４−メチルペンタン酸、ｎ−ヘプタン酸、２−メチルヘキサン酸、ｎ−オクタン酸、２−エチルヘキサン酸、安息香酸、グリコール酸、サリチル酸、グリセリン酸、シュウ酸、マロン酸、コハク酸、グルタル酸、アジピン酸、ピメリン酸、マレイン酸、フタル酸、リンゴ酸、酒石酸、クエン酸等、及びこれらの有機酸のアンモニウム塩等の塩、硫酸、硝酸、アンモニア、アンモニウム塩類、例えば過硫酸アンモニウム、硝酸アンモニウム、塩化アンモニウム、クロム酸等又はそれらの混合物等が挙げられる。これらの中では、実用的なＣＭＰ研磨速度が得られるという点で有機酸、特に、マロン酸、リンゴ酸、酒石酸、グリコール酸及びクエン酸が好ましい。 Examples of the acid in the present invention include formic acid, acetic acid, propionic acid, valeric acid, 2-methylbutyric acid, n-hexanoic acid, 3,3-dimethylbutyric acid, 2-ethylbutyric acid, 4-methylpentanoic acid, n-heptanoic acid, 2-methylhexanoic acid, n-octanoic acid, 2-ethylhexanoic acid, benzoic acid, glycolic acid, salicylic acid, glyceric acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, maleic acid, phthalate Acids, malic acid, tartaric acid, citric acid, etc., and salts such as ammonium salts of these organic acids, sulfuric acid, nitric acid, ammonia, ammonium salts such as ammonium persulfate, ammonium nitrate, ammonium chloride, chromic acid, etc., or mixtures thereof Can be mentioned. Among these, organic acids, particularly malonic acid, malic acid, tartaric acid, glycolic acid and citric acid are preferable in that a practical CMP polishing rate can be obtained.
本発明における金属表面に対する保護膜形成剤は、ＢＴＡ（ベンゾトリアゾール）及びその誘導体、例えばＢＴＡのベンゼン環の一つの水素原子をメチル基で置換したもの（トリルトリアゾール）もしくはカルボキシル基等で置換したもの（ベンゾトリアゾール−４−カルボン酸のメチル、エチル、プロピル、ブチル及びオクチルエステル）、又はナフトトリアゾール、ナフトトリアゾール誘導体及びこれらを含む混合物の中から選ばれた少なくとも１種が好ましく用いられる。 The protective film forming agent for the metal surface in the present invention is BTA (benzotriazole) and its derivatives, for example, one in which one hydrogen atom of the benzene ring of BTA is substituted with a methyl group (tolyltriazole) or a carboxyl group. (Methyl, ethyl, propyl, butyl and octyl esters of benzotriazole-4-carboxylic acid), or at least one selected from naphthotriazole, naphthotriazole derivatives and mixtures containing these is preferably used.
本発明における水溶性高分子としては、以下の群から選ばれた少なくとも１種が好適に用いられる。すなわち、ポリアクリル酸、ポリアクリル酸アンモニウム塩、ポリアクリル酸ナトリウム塩、ポリメタクリル酸、ポリメタクリル酸アンモニウム塩、ポリメタクリル酸ナトリウム塩、ポリアクリルアミド等のカルボキシル基を持つモノマーを基本構成単位とするポリマー及びその塩、ポリビニルアルコール及びポリビニルピロリドン等のビニル基を持つモノマーを基本構成単位とするポリマーからなる群が挙げられる。但し、適用する基板が半導体集積回路用シリコン基板などの場合はアルカリ金属、アルカリ土類金属、ハロゲン化物等による汚染は望ましくないため、酸もしくはそのアンモニウム塩が望ましい。基板がガラス基板等である場合はその限りではない。これらの水溶性高分子を添加することにより、前記保護膜形成剤によるエッチング抑止効果によりディッシング特性を向上させることができる。 As the water-soluble polymer in the present invention, at least one selected from the following groups is preferably used. That is, a polymer having a basic structural unit as a monomer having a carboxyl group, such as polyacrylic acid, polyacrylic acid ammonium salt, polyacrylic acid sodium salt, polymethacrylic acid, polymethacrylic acid ammonium salt, polymethacrylic acid sodium salt, polyacrylamide And salts thereof, a group consisting of a polymer having a monomer having a vinyl group such as polyvinyl alcohol and polyvinylpyrrolidone as a basic structural unit. However, when the substrate to be applied is a silicon substrate for a semiconductor integrated circuit or the like, contamination with an alkali metal, an alkaline earth metal, a halide, or the like is not desirable, so an acid or an ammonium salt thereof is desirable. This is not the case when the substrate is a glass substrate or the like. By adding these water-soluble polymers, dishing characteristics can be improved due to the effect of inhibiting etching by the protective film forming agent.
本発明の導体用研磨液の砥粒としては、シリカ、アルミナ、ジルコニア、セリア、チタニア、ゲルマニア、炭化珪素等の無機物砥粒、ポリスチレン、ポリアクリル酸、ポリ塩化ビニル等の有機物砥粒のいずれでもよいが、研磨液中での分散安定性が良く、ＣＭＰにより発生する研磨傷（スクラッチ）の発生数の少ない、平均粒径が６０ｎｍ以下のコロイダルシリカ、コロイダルアルミナが好ましく、平均粒径が５０ｎｍ以下のコロイダルシリカ、コロイダルアルミナがより好ましい。平均粒径は、バリア層の研磨速度がより大きくなり、二酸化シリコンの研磨速度がより小さくなる３０ｎｍ以下が更に好ましい。コロイダルシリカはシリコンアルコキシドの加水分解又は珪酸ナトリウムのイオン交換による製造方法が知られており、コロイダルアルミナは硝酸アルミニウムの加水分解による製造方法が知られている。 The abrasive grains for the conductor polishing liquid of the present invention may be any of inorganic abrasive grains such as silica, alumina, zirconia, ceria, titania, germania, silicon carbide, and organic abrasive grains such as polystyrene, polyacrylic acid, and polyvinyl chloride. However, colloidal silica or colloidal alumina having an average particle size of 60 nm or less is preferred, since the dispersion stability in the polishing liquid is good, the number of polishing scratches (scratches) generated by CMP is small, and the average particle size is 50 nm. The following colloidal silica and colloidal alumina are more preferable. The average particle diameter is more preferably 30 nm or less, in which the polishing rate of the barrier layer becomes larger and the polishing rate of silicon dioxide becomes smaller. Colloidal silica is known for its production by hydrolysis of silicon alkoxide or ion exchange of sodium silicate, and colloidal alumina is known for its production by hydrolysis of aluminum nitrate.
本発明を適用する導体としては、基板に導体として埋め込まれ、研磨されて平坦化されて電導性を有する配線材料となるものであれば、特に限定されないが、銅又は銅合金のバリア層となる導体であることが好ましく、タンタルやタンタル合金及び窒化タンタルやその他のタンタル化合物が好ましい。 The conductor to which the present invention is applied is not particularly limited as long as it becomes a conductive wiring material embedded in a substrate, polished and flattened, and becomes a barrier layer of copper or copper alloy. A conductor is preferable, and tantalum, a tantalum alloy, tantalum nitride, and other tantalum compounds are preferable.
本発明における酸の配合量は、導体の酸化剤、酸、金属表面に対する保護膜形成剤、必要により配合される水溶性高分子及び水の総量１００ｇに対して、０．０００１〜０．０５molとすることが好ましく、０．００１mol〜０．０１molとすることがより好ましい。この配合量が０．０５molを超えると、銅合金のエッチングが増加する傾向がある。 The amount of the acid in the present invention is 0.0001 to 0.05 mol with respect to 100 g of the total amount of the oxidizing agent of the conductor, the acid, the protective film forming agent for the metal surface, the water-soluble polymer and water mixed as necessary. It is preferable to make it 0.001 mol to 0.01 mol. If this amount exceeds 0.05 mol, etching of the copper alloy tends to increase.
本発明における金属表面に対する保護膜形成剤の配合量は、導体の酸化剤、酸、金属表面に対する保護膜形成剤、必要により配合される水溶性高分子及び水の総量１００ｇに対して、０．０００１mol〜０．０１molとすることが好ましく、０．０００５mol〜０．００５molとすることがより好ましい。この配合量が０．０００１mol未満では、銅合金のエッチングが増加する傾向があり、０．０１molを超えても効果に変わりがない。 The blending amount of the protective film forming agent for the metal surface in the present invention is 0. 0 g with respect to 100 g of the total amount of the conductor oxidizing agent, acid, protective film forming agent for the metal surface, water-soluble polymer and water blended as necessary. It is preferable to set it as 0001 mol-0.01 mol, and it is more preferable to set it as 0.0005 mol-0.005 mol. If the amount is less than 0.0001 mol, the etching of the copper alloy tends to increase, and if it exceeds 0.01 mol, the effect remains unchanged.
本発明における水溶性高分子の配合量は、導体の酸化剤、酸、金属表面に対する保護膜形成剤、水溶性高分子及び水の総量１００ｇに対して、０．００１〜０．５重量％とすることが好ましく、０．０１重量％〜０．２重量％とすることがより好ましい。この配合量が０．００１重量％未満では、エッチング抑制において保護膜形成剤との併用効果が現れない傾向があり、０．５重量％を超えると、ＣＭＰによる研磨速度が低下する傾向がある。 The blending amount of the water-soluble polymer in the present invention is 0.001 to 0.5% by weight based on 100 g of the total amount of the conductor oxidizing agent, acid, protective film forming agent for the metal surface, water-soluble polymer and water. It is preferable to make it 0.01% to 0.2% by weight. If the blending amount is less than 0.001% by weight, the combined effect with the protective film forming agent tends not to appear in etching suppression, and if it exceeds 0.5% by weight, the polishing rate by CMP tends to decrease.
以下、実施例により本発明を説明する。本発明はこれらの実施例により制限されるものではない。 Hereinafter, the present invention will be described by way of examples. The present invention is not limited by these examples.
実施例１〜３、比較例１〜３
《研磨液の作製方法》
リンゴ酸０．４重量％、砥粒１．０重量％及び保護膜形成剤としてのＢＴＡ０．２重量％に水９７．９重量％を加えて溶解し、過酸化水素水（試薬特級、３０％水溶液）を０．５重量％加えて得られたものを導体用研磨液とした。
砥粒としては、テトラエトキシシランのアンモニア溶液中での加水分解により作製し、テトラエトキシシラン濃度、アンモニア濃度、反応温度を調整することにより砥粒粒径、凝集数を調整して得られた表１に示す砥粒粒径２５〜１００ｎｍの範囲のコロイダルシリカを用いた。使用したリンゴ酸のｐＫａは、３．４である。
実施例１〜３、比較例１〜３では表１に示す砥粒を含む上記導体用研磨液を用いてＣＭＰした。
Examples 1-3, Comparative Examples 1-3
<< Method for preparing polishing liquid >>
Water 97.9% by weight was dissolved in malic acid 0.4% by weight, abrasive grains 1.0% by weight and BTA 0.2% by weight as a protective film forming agent, and dissolved in hydrogen peroxide (special grade, 30% A solution obtained by adding 0.5% by weight of an aqueous solution was used as a polishing slurry for conductors.
The abrasive grains were prepared by hydrolysis of tetraethoxysilane in an ammonia solution, and the grain diameter and aggregation number were adjusted by adjusting the tetraethoxysilane concentration, ammonia concentration, and reaction temperature. Colloidal silica having an abrasive grain diameter of 25 to 100 nm shown in FIG. The pKa of malic acid used is 3.4.
In Examples 1 to 3 and Comparative Examples 1 to 3, CMP was performed using the conductor polishing liquid containing abrasive grains shown in Table 1.
《研磨条件》
基板：
厚さ２００ｎｍのタンタル膜を形成した配線形成のない二酸化シリコン膜層付きシリコン基板
厚さ１００ｎｍの窒化タンタル膜を形成した配線形成のない二酸化シリコン膜層付きシリコン基板
厚さ１μｍの二酸化シリコン膜を形成したシリコン基板
厚さ１μｍの銅膜を形成した配線形成のない二酸化シリコン膜層付きシリコン基板
銅配線パターン付きシリコン基板
研磨パッド：独立気泡を持つ発泡ポリウレタン樹脂
研磨圧力：２５ＫＰａ
基板と研磨定盤との相対速度：１８ｍ／ｍｉｎ
<Polishing conditions>
substrate:
A silicon substrate with a silicon dioxide film layer without a wiring formation on which a tantalum film with a thickness of 200 nm is formed A silicon substrate with a silicon dioxide film layer without a wiring formation with a tantalum nitride film with a thickness of 100 nm is formed on the silicon substrate with a thickness of 1 μm A silicon substrate with a silicon dioxide film layer without a wiring formed with a copper film having a thickness of 1 μm and a silicon substrate with a copper wiring pattern Polishing pad: Foam polyurethane resin with closed cells Polishing pressure: 25 KPa
Relative speed between substrate and polishing surface plate: 18 m / min
《研磨品評価項目》
ＣＭＰによる研磨速度：タンタル膜、窒化タンタル膜、銅膜については、例えばナプソン（株）製Ｍｏｄｅｌ ＲＴ−７を用いてシート抵抗値を測定し、抵抗率から膜厚を計算し、ＣＭＰ前後での膜厚差を求めた。このとき、銅膜の抵抗率は１．８３μΩｃｍ、タンタル膜の抵抗率は１８４μΩｃｍ、窒化タンタル膜の抵抗率は２６３μΩｃｍを用いた。二酸化シリコン膜の膜厚は光干渉式膜厚計（例えばナノメトリクス（株）製、Nanospec Model 5100）で測定し、ＣＭＰ前後の膜厚差を求めた。このとき二酸化シリコン膜の屈折率は１．４５を用いた。
《Abrasive product evaluation items》
Polishing rate by CMP: For tantalum film, tantalum nitride film, copper film, for example, the sheet resistance value is measured using Model RT-7 manufactured by Napson Co., Ltd., the film thickness is calculated from the resistivity, and before and after the CMP. The film thickness difference was determined. At this time, the resistivity of the copper film was 1.83 μΩcm, the resistivity of the tantalum film was 184 μΩcm, and the resistivity of the tantalum nitride film was 263 μΩcm. The film thickness of the silicon dioxide film was measured with a light interference film thickness meter (for example, Nanospec Model 5100 manufactured by Nanometrics Co., Ltd.), and the film thickness difference before and after CMP was determined. At this time, the refractive index of the silicon dioxide film was 1.45.
ディッシング量：二酸化シリコン中に深さ０．５μｍの溝を形成して、公知のスパッタ法によってバリア層として厚さ５０ｎｍの窒化タンタル膜を形成し、同様にスパッタ法により銅膜を形成して公知の熱処理によって埋め込んだシリコン基板を基板として用いて銅膜の研磨とバリア層の研磨とからなる２段研磨を行い、触針式段差計（例えば、Ｖｅｅｃｏ／Ｓｌｏａｎ社製Ｄｅｋｔａｔ３０３０）で配線金属部（銅）幅１００μｍ、絶縁膜（二酸化シリコン）部幅１００μｍが交互に並んだストライプ状パターン部の表面形状から、絶縁膜部に対する配線金属部の膜減り量を測定し、表２に示した。
銅膜用の１段目研磨液としては、窒化タンタルに対する銅の研磨速度比が十分大きい銅及び銅合金用の研磨液（日立砥粒フリーＣ４３０Ｋスラリー）を使用して研磨した。１段研磨後に、絶縁膜部上にバリア層が露出した状態で測定したディッシング量が、５０ｎｍになるように基板サンプルを作製しておき、次に、バリア層用の２段目研磨液として、実施例及び比較例の研磨液を用いて絶縁膜部でバリア層がなくなるまで２段研磨し、配線金属部の膜減り量を測定した。
Dishing amount: A groove having a depth of 0.5 μm is formed in silicon dioxide, a tantalum nitride film having a thickness of 50 nm is formed as a barrier layer by a known sputtering method, and a copper film is similarly formed by sputtering. The silicon substrate embedded by the heat treatment is used as a substrate to perform a two-step polishing consisting of a copper film polishing and a barrier layer polishing, and a wiring metal portion (for example, Dektat 3030 manufactured by Veeco / Sloan) with a stylus step meter. The amount of reduction of the wiring metal part relative to the insulating film part was measured from the surface shape of the stripe pattern part in which the copper) width of 100 μm and the insulating film (silicon dioxide) part width of 100 μm were alternately arranged.
Polishing was performed using a polishing solution for copper and copper alloy (Hitachi abrasive-free C430K slurry) having a sufficiently high polishing rate ratio of copper to tantalum nitride as the first-stage polishing solution for the copper film. After the first stage polishing, a substrate sample was prepared so that the dishing amount measured with the barrier layer exposed on the insulating film portion was 50 nm. Next, as the second stage polishing liquid for the barrier layer, Using the polishing liquids of Examples and Comparative Examples, the insulating film portion was polished in two steps until the barrier layer disappeared, and the amount of film reduction of the wiring metal portion was measured.
シニング量：上記ディッシング量評価用基板に形成された配線金属部幅４．５μｍ、絶縁膜部幅０．５μｍが交互に並んだ総幅２．５ｍｍのストライプ状パターン部を上記と同じ研磨液を用いて、銅膜の研磨とバリア層の研磨とからなる２段研磨を行い、表面形状を触針式段差計により測定し、ストライプ状パターン周辺の絶縁膜フィールド部に対するパターン中央付近の絶縁膜部の膜減り量を測定し、表２に示した。１段研磨は、１段研磨後に、絶縁膜部上にバリア層が露出した状態で測定したシニング量が２０ｎｍになるように行って基板サンプルを作製しておき、次に絶縁膜部でバリア層がなくなるまで２段研磨を行い、このときの膜減り量を測定した。 Thinning amount: Striped pattern portion having a total width of 2.5 mm in which the wiring metal portion width of 4.5 μm and the insulating film portion width of 0.5 μm are alternately formed on the dishing amount evaluation substrate is applied with the same polishing liquid as above. The two-stage polishing consisting of the copper film polishing and the barrier layer polishing is used, the surface shape is measured by a stylus type step meter, and the insulating film portion near the center of the pattern with respect to the insulating film field portion around the stripe pattern The film loss was measured and shown in Table 2. In the first-stage polishing, after the first-stage polishing, a substrate sample is prepared by performing a thinning amount measured with the barrier layer exposed on the insulating film portion to be 20 nm, and then the barrier layer is formed on the insulating film portion. Two-stage polishing was performed until the film disappeared, and the amount of film loss at this time was measured.
実施例１〜３、比較例１〜３における、ＣＭＰによる研磨速度は表１に示すようであり、ディッシング量及びシニング量は表２に示すようであった。 The polishing rate by CMP in Examples 1 to 3 and Comparative Examples 1 to 3 was as shown in Table 1, and the dishing amount and the thinning amount were as shown in Table 2.
実施例１〜３では、バリア層導体であるタンタル及び窒化タンタル膜の研磨速度が大きく、二酸化シリコン膜の研磨速度が比較的小さいので、良好なディッシング及びシニング特性が得られる。それに対し、比較例１及び３では、バリア層膜（タンタル膜）の研磨速度が減少し、二酸化シリコン膜の研磨速度がかなり大きくなるためにディッシング及びシニング特性が悪化した。比較例２では、バリア層膜（タンタル膜）の研磨速度は大きいが、二酸化シリコン膜の研磨速度がかなり大きくなるためにディッシング及びシニング特性が悪化した。 In Examples 1 to 3, since the polishing rate of the tantalum and tantalum nitride films as the barrier layer conductors is high and the polishing rate of the silicon dioxide film is relatively low, good dishing and thinning characteristics can be obtained. On the other hand, in Comparative Examples 1 and 3, the polishing rate of the barrier layer film (tantalum film) was decreased, and the polishing rate of the silicon dioxide film was considerably increased, so that dishing and thinning characteristics were deteriorated. In Comparative Example 2, the polishing rate of the barrier layer film (tantalum film) was high, but the polishing rate of the silicon dioxide film was considerably increased, so that dishing and thinning characteristics were deteriorated.
Claims (9)
前記基板を、銅膜研磨用研磨液を用いて、前記凹部内には銅膜が残って前記二酸化シリコン膜で形成された凸部上のバリア層が露出するまで研磨し、
次いで、前記研磨後の基板を、前記二酸化シリコン膜で形成された凸部上のバリア層がなくなるまで、バリア層研磨用研磨液でさらに研磨することを特徴とし、
上記導体は、タンタル、窒化タンタル、タンタル合金又はその他のタンタル化合物であり、
上記銅膜は、銅又は銅合金の膜であり、
上記バリア層研磨用研磨液は、砥粒、上記導体の酸化剤、金属表面に対する保護膜形成剤、酸及び水を含有し、
上記砥粒が、一次粒子が平均２〜３粒子凝集した平均粒径が６０ｎｍ以下の２次粒子からなる粒子であり、
上記バリア層研磨用研磨液ｐＨが３以下であり、
かつ導体の酸化剤の濃度が０．０１〜３重量％である研磨方法。 On a substrate having a recess formed in the silicon dioxide film, a barrier layer made of a conductor serving as a barrier layer of copper or a copper alloy, a substrate was prepared having the embedded structure further form a copper film,
The substrate is polished using a polishing slurry for copper film until the copper film remains in the recess and the barrier layer on the protrusion formed of the silicon dioxide film is exposed,
Next, the polished substrate is further polished with a barrier layer polishing polishing liquid until there is no barrier layer on the convex portion formed of the silicon dioxide film,
The conductor is tantalum, tantalum nitride, tantalum alloy or other tantalum compound,
The copper film is a copper or copper alloy film,
The barrier layer polishing abrasive liquid, abrasive grains, oxidizing agent of the conductor, the protective film forming agent to the metal surface, contains an acid and water,
The abrasive grains are particles composed of secondary particles having an average particle size of 60 nm or less in which the primary particles are aggregated on average 2 to 3 particles,
The barrier layer polishing polishing solution has a pH of 3 or less,
And the concentration of the oxidizing agent conductors 0.01-3 wt% der Ru Migaku Ken method.
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| JPH04224221A (en) * | 1990-12-26 | 1992-08-13 | Toyota Motor Corp | Exhaust purification device for diesel engine |
| JPH1121546A (en) * | 1996-12-09 | 1999-01-26 | Cabot Corp | Chemical/mechanical polishing slurry useful for copper substrate |
| JP2000233361A (en) * | 1998-12-14 | 2000-08-29 | Matsushita Electronics Industry Corp | Polishing liquid for chemicomechanical polishing and polishing method therefor |
| WO2001013417A1 (en) * | 1999-08-17 | 2001-02-22 | Hitachi Chemical Company, Ltd. | Polishing compound for chemimechanical polishing and method for polishing substrate |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| JPH04224221A (en) * | 1990-12-26 | 1992-08-13 | Toyota Motor Corp | Exhaust purification device for diesel engine |
| JPH1121546A (en) * | 1996-12-09 | 1999-01-26 | Cabot Corp | Chemical/mechanical polishing slurry useful for copper substrate |
| JP2000233361A (en) * | 1998-12-14 | 2000-08-29 | Matsushita Electronics Industry Corp | Polishing liquid for chemicomechanical polishing and polishing method therefor |
| WO2001013417A1 (en) * | 1999-08-17 | 2001-02-22 | Hitachi Chemical Company, Ltd. | Polishing compound for chemimechanical polishing and method for polishing substrate |
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