JP6938855B2 - Polishing liquid for CMP and polishing method using it - Google Patents
Polishing liquid for CMP and polishing method using it Download PDFInfo
- Publication number
- JP6938855B2 JP6938855B2 JP2016102148A JP2016102148A JP6938855B2 JP 6938855 B2 JP6938855 B2 JP 6938855B2 JP 2016102148 A JP2016102148 A JP 2016102148A JP 2016102148 A JP2016102148 A JP 2016102148A JP 6938855 B2 JP6938855 B2 JP 6938855B2
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- Prior art keywords
- polishing
- acid
- polishing liquid
- cmp
- mass
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- 238000005498 polishing Methods 0.000 title claims description 305
- 239000007788 liquid Substances 0.000 title claims description 145
- 238000000034 method Methods 0.000 title claims description 60
- 239000006061 abrasive grain Substances 0.000 claims description 73
- 239000000758 substrate Substances 0.000 claims description 68
- 239000000654 additive Substances 0.000 claims description 45
- 230000000996 additive effect Effects 0.000 claims description 40
- 239000002245 particle Substances 0.000 claims description 31
- 229910000420 cerium oxide Inorganic materials 0.000 claims description 28
- BMMGVYCKOGBVEV-UHFFFAOYSA-N oxo(oxoceriooxy)cerium Chemical compound [Ce]=O.O=[Ce]=O BMMGVYCKOGBVEV-UHFFFAOYSA-N 0.000 claims description 28
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 24
- 239000004065 semiconductor Substances 0.000 claims description 21
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Natural products CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 claims description 14
- 229920006395 saturated elastomer Polymers 0.000 claims description 11
- FERIUCNNQQJTOY-UHFFFAOYSA-N Butyric acid Chemical compound CCCC(O)=O FERIUCNNQQJTOY-UHFFFAOYSA-N 0.000 claims description 8
- OXQGTIUCKGYOAA-UHFFFAOYSA-N 2-Ethylbutanoic acid Chemical compound CCC(CC)C(O)=O OXQGTIUCKGYOAA-UHFFFAOYSA-N 0.000 claims description 6
- OVBFMEVBMNZIBR-UHFFFAOYSA-N 2-methylvaleric acid Chemical compound CCCC(C)C(O)=O OVBFMEVBMNZIBR-UHFFFAOYSA-N 0.000 claims description 6
- 239000002253 acid Substances 0.000 claims description 6
- XBDQKXXYIPTUBI-UHFFFAOYSA-N dimethylselenoniopropionate Natural products CCC(O)=O XBDQKXXYIPTUBI-UHFFFAOYSA-N 0.000 claims description 6
- FUZZWVXGSFPDMH-UHFFFAOYSA-N hexanoic acid Chemical compound CCCCCC(O)=O FUZZWVXGSFPDMH-UHFFFAOYSA-N 0.000 claims description 6
- KQNPFQTWMSNSAP-UHFFFAOYSA-N isobutyric acid Chemical compound CC(C)C(O)=O KQNPFQTWMSNSAP-UHFFFAOYSA-N 0.000 claims description 6
- FGKJLKRYENPLQH-UHFFFAOYSA-N isocaproic acid Chemical compound CC(C)CCC(O)=O FGKJLKRYENPLQH-UHFFFAOYSA-N 0.000 claims description 6
- 239000002736 nonionic surfactant Substances 0.000 claims description 6
- 239000003002 pH adjusting agent Substances 0.000 claims description 6
- NQPDZGIKBAWPEJ-UHFFFAOYSA-N valeric acid Chemical compound CCCCC(O)=O NQPDZGIKBAWPEJ-UHFFFAOYSA-N 0.000 claims description 6
- 150000002763 monocarboxylic acids Chemical class 0.000 claims description 4
- XYHKNCXZYYTLRG-UHFFFAOYSA-N 1h-imidazole-2-carbaldehyde Chemical compound O=CC1=NC=CN1 XYHKNCXZYYTLRG-UHFFFAOYSA-N 0.000 claims description 3
- VUAXHMVRKOTJKP-UHFFFAOYSA-N 2,2-dimethylbutyric acid Chemical compound CCC(C)(C)C(O)=O VUAXHMVRKOTJKP-UHFFFAOYSA-N 0.000 claims description 3
- MLMQPDHYNJCQAO-UHFFFAOYSA-N 3,3-dimethylbutyric acid Chemical compound CC(C)(C)CC(O)=O MLMQPDHYNJCQAO-UHFFFAOYSA-N 0.000 claims description 3
- GWYFCOCPABKNJV-UHFFFAOYSA-M 3-Methylbutanoic acid Natural products CC(C)CC([O-])=O GWYFCOCPABKNJV-UHFFFAOYSA-M 0.000 claims description 3
- NBKYPRRBTKRGLE-UHFFFAOYSA-N Maltol propionate Chemical compound CCC(=O)OC1=C(C)OC=CC1=O NBKYPRRBTKRGLE-UHFFFAOYSA-N 0.000 claims description 3
- GWYFCOCPABKNJV-UHFFFAOYSA-N beta-methyl-butyric acid Natural products CC(C)CC(O)=O GWYFCOCPABKNJV-UHFFFAOYSA-N 0.000 claims description 3
- IUGYQRQAERSCNH-UHFFFAOYSA-N pivalic acid Chemical compound CC(C)(C)C(O)=O IUGYQRQAERSCNH-UHFFFAOYSA-N 0.000 claims description 3
- 235000019260 propionic acid Nutrition 0.000 claims description 3
- 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 claims description 3
- 229940005605 valeric acid Drugs 0.000 claims description 3
- XBDQKXXYIPTUBI-UHFFFAOYSA-M Propionate Chemical compound CCC([O-])=O XBDQKXXYIPTUBI-UHFFFAOYSA-M 0.000 claims 1
- 125000000218 acetic acid group Chemical group C(C)(=O)* 0.000 claims 1
- 239000010408 film Substances 0.000 description 164
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 76
- 229910052814 silicon oxide Inorganic materials 0.000 description 72
- -1 4-pyrone compound Chemical class 0.000 description 39
- 230000000694 effects Effects 0.000 description 19
- 150000001875 compounds Chemical class 0.000 description 18
- 239000000243 solution Substances 0.000 description 15
- 230000002776 aggregation Effects 0.000 description 12
- 229910052581 Si3N4 Inorganic materials 0.000 description 11
- 238000004220 aggregation Methods 0.000 description 11
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 description 11
- 230000008569 process Effects 0.000 description 10
- 239000004094 surface-active agent Substances 0.000 description 10
- 238000000926 separation method Methods 0.000 description 9
- 238000005516 engineering process Methods 0.000 description 8
- 239000000843 powder Substances 0.000 description 8
- 229910052684 Cerium Inorganic materials 0.000 description 7
- 125000004432 carbon atom Chemical group C* 0.000 description 7
- GWXLDORMOJMVQZ-UHFFFAOYSA-N cerium Chemical compound [Ce] GWXLDORMOJMVQZ-UHFFFAOYSA-N 0.000 description 7
- 238000004519 manufacturing process Methods 0.000 description 7
- 150000002762 monocarboxylic acid derivatives Chemical class 0.000 description 7
- 239000006174 pH buffer Substances 0.000 description 7
- 229920003171 Poly (ethylene oxide) Polymers 0.000 description 6
- 230000008901 benefit Effects 0.000 description 6
- 235000014113 dietary fatty acids Nutrition 0.000 description 6
- 239000000194 fatty acid Substances 0.000 description 6
- 229930195729 fatty acid Natural products 0.000 description 6
- 238000010304 firing Methods 0.000 description 6
- 238000005268 plasma chemical vapour deposition Methods 0.000 description 6
- 238000003860 storage Methods 0.000 description 6
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 5
- 125000002915 carbonyl group Chemical group [*:2]C([*:1])=O 0.000 description 5
- 238000005229 chemical vapour deposition Methods 0.000 description 5
- 238000009826 distribution Methods 0.000 description 5
- 230000003287 optical effect Effects 0.000 description 5
- 229910052710 silicon Inorganic materials 0.000 description 5
- 239000010703 silicon Substances 0.000 description 5
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 4
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 4
- 239000013078 crystal Substances 0.000 description 4
- PGRHXDWITVMQBC-UHFFFAOYSA-N dehydroacetic acid Chemical compound CC(=O)C1C(=O)OC(C)=CC1=O PGRHXDWITVMQBC-UHFFFAOYSA-N 0.000 description 4
- 238000010790 dilution Methods 0.000 description 4
- 239000012895 dilution Substances 0.000 description 4
- 125000006353 oxyethylene group Chemical group 0.000 description 4
- 238000002360 preparation method Methods 0.000 description 4
- 238000010298 pulverizing process Methods 0.000 description 4
- 125000001424 substituent group Chemical group 0.000 description 4
- PEDCQBHIVMGVHV-UHFFFAOYSA-N Glycerine Chemical compound OCC(O)CO PEDCQBHIVMGVHV-UHFFFAOYSA-N 0.000 description 3
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical group OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 3
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 description 3
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 3
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 3
- 230000008859 change Effects 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 3
- 239000008367 deionised water Substances 0.000 description 3
- 229910021641 deionized water Inorganic materials 0.000 description 3
- 239000007789 gas Substances 0.000 description 3
- 239000011521 glass Substances 0.000 description 3
- 125000004435 hydrogen atom Chemical group [H]* 0.000 description 3
- 125000002887 hydroxy group Chemical group [H]O* 0.000 description 3
- 238000004518 low pressure chemical vapour deposition Methods 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 239000011259 mixed solution Substances 0.000 description 3
- 229910052757 nitrogen Inorganic materials 0.000 description 3
- 125000001820 oxy group Chemical group [*:1]O[*:2] 0.000 description 3
- 239000001301 oxygen Substances 0.000 description 3
- 229910052760 oxygen Inorganic materials 0.000 description 3
- 238000007517 polishing process Methods 0.000 description 3
- 239000012495 reaction gas Substances 0.000 description 3
- 239000002002 slurry Substances 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 description 2
- BTBUEUYNUDRHOZ-UHFFFAOYSA-N Borate Chemical compound [O-]B([O-])[O-] BTBUEUYNUDRHOZ-UHFFFAOYSA-N 0.000 description 2
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- 239000004287 Dehydroacetic acid Substances 0.000 description 2
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 2
- LYCAIKOWRPUZTN-UHFFFAOYSA-N Ethylene glycol Chemical compound OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 description 2
- TZXKOCQBRNJULO-UHFFFAOYSA-N Ferriprox Chemical compound CC1=C(O)C(=O)C=CN1C TZXKOCQBRNJULO-UHFFFAOYSA-N 0.000 description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 2
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 description 2
- CPLXHLVBOLITMK-UHFFFAOYSA-N Magnesium oxide Chemical compound [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 description 2
- 229910019142 PO4 Inorganic materials 0.000 description 2
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 2
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 2
- BOTDANWDWHJENH-UHFFFAOYSA-N Tetraethyl orthosilicate Chemical compound CCO[Si](OCC)(OCC)OCC BOTDANWDWHJENH-UHFFFAOYSA-N 0.000 description 2
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 2
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 2
- 150000005215 alkyl ethers Chemical class 0.000 description 2
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 2
- 229910021529 ammonia Inorganic materials 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 239000000872 buffer Substances 0.000 description 2
- 229910052799 carbon Inorganic materials 0.000 description 2
- 125000003178 carboxy group Chemical group [H]OC(*)=O 0.000 description 2
- GHLITDDQOMIBFS-UHFFFAOYSA-H cerium(3+);tricarbonate Chemical compound [Ce+3].[Ce+3].[O-]C([O-])=O.[O-]C([O-])=O.[O-]C([O-])=O GHLITDDQOMIBFS-UHFFFAOYSA-H 0.000 description 2
- HSJPMRKMPBAUAU-UHFFFAOYSA-N cerium(3+);trinitrate Chemical compound [Ce+3].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O HSJPMRKMPBAUAU-UHFFFAOYSA-N 0.000 description 2
- MOOUSOJAOQPDEH-UHFFFAOYSA-K cerium(iii) bromide Chemical compound [Br-].[Br-].[Br-].[Ce+3] MOOUSOJAOQPDEH-UHFFFAOYSA-K 0.000 description 2
- 229910052801 chlorine Inorganic materials 0.000 description 2
- 239000000460 chlorine Substances 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 230000008878 coupling Effects 0.000 description 2
- 238000010168 coupling process Methods 0.000 description 2
- 238000005859 coupling reaction Methods 0.000 description 2
- 235000019258 dehydroacetic acid Nutrition 0.000 description 2
- 229940061632 dehydroacetic acid Drugs 0.000 description 2
- 239000006185 dispersion Substances 0.000 description 2
- 239000002612 dispersion medium Substances 0.000 description 2
- 238000002296 dynamic light scattering Methods 0.000 description 2
- 238000011156 evaluation Methods 0.000 description 2
- 150000004665 fatty acids Chemical class 0.000 description 2
- 239000010419 fine particle Substances 0.000 description 2
- 150000002391 heterocyclic compounds Chemical group 0.000 description 2
- 230000003993 interaction Effects 0.000 description 2
- 229910052740 iodine Inorganic materials 0.000 description 2
- 239000007791 liquid phase Substances 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 230000007935 neutral effect Effects 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 description 2
- 239000010452 phosphate Substances 0.000 description 2
- 229910052698 phosphorus Inorganic materials 0.000 description 2
- 239000011574 phosphorus Substances 0.000 description 2
- XNGIFLGASWRNHJ-UHFFFAOYSA-L phthalate(2-) Chemical compound [O-]C(=O)C1=CC=CC=C1C([O-])=O XNGIFLGASWRNHJ-UHFFFAOYSA-L 0.000 description 2
- 229910021420 polycrystalline silicon Inorganic materials 0.000 description 2
- 238000003825 pressing Methods 0.000 description 2
- 238000004062 sedimentation Methods 0.000 description 2
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 description 2
- 229910010271 silicon carbide Inorganic materials 0.000 description 2
- 239000006228 supernatant Substances 0.000 description 2
- XFOASZQZPWEJAA-UHFFFAOYSA-N 2,3-dimethylbutyric acid Chemical compound CC(C)C(C)C(O)=O XFOASZQZPWEJAA-UHFFFAOYSA-N 0.000 description 1
- MPOYBFYHRQBZPM-UHFFFAOYSA-N 3h-pyridin-4-one Chemical class O=C1CC=NC=C1 MPOYBFYHRQBZPM-UHFFFAOYSA-N 0.000 description 1
- GCNTZFIIOFTKIY-UHFFFAOYSA-N 4-hydroxypyridine Chemical group OC1=CC=NC=C1 GCNTZFIIOFTKIY-UHFFFAOYSA-N 0.000 description 1
- UVKPUDRFBHSFJH-UHFFFAOYSA-N 5-(3-bromophenyl)-2h-tetrazole Chemical compound BrC1=CC=CC(C2=NNN=N2)=C1 UVKPUDRFBHSFJH-UHFFFAOYSA-N 0.000 description 1
- ZCYVEMRRCGMTRW-UHFFFAOYSA-N 7553-56-2 Chemical group [I] ZCYVEMRRCGMTRW-UHFFFAOYSA-N 0.000 description 1
- 229910052580 B4C Inorganic materials 0.000 description 1
- 238000004438 BET method Methods 0.000 description 1
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 description 1
- WKBOTKDWSSQWDR-UHFFFAOYSA-N Bromine atom Chemical group [Br] WKBOTKDWSSQWDR-UHFFFAOYSA-N 0.000 description 1
- KXDHJXZQYSOELW-UHFFFAOYSA-N Carbamic acid Chemical compound NC(O)=O KXDHJXZQYSOELW-UHFFFAOYSA-N 0.000 description 1
- 229910005540 GaP Inorganic materials 0.000 description 1
- 229910001218 Gallium arsenide Inorganic materials 0.000 description 1
- HYMLWHLQFGRFIY-UHFFFAOYSA-N Maltol Natural products CC1OC=CC(=O)C1=O HYMLWHLQFGRFIY-UHFFFAOYSA-N 0.000 description 1
- 229910004013 NO 2 Inorganic materials 0.000 description 1
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 1
- 239000002202 Polyethylene glycol Substances 0.000 description 1
- 229920001214 Polysorbate 60 Polymers 0.000 description 1
- 229920005830 Polyurethane Foam Polymers 0.000 description 1
- 239000004372 Polyvinyl alcohol Substances 0.000 description 1
- CVQUWLDCFXOXEN-UHFFFAOYSA-N Pyran-4-one Chemical group O=C1C=COC=C1 CVQUWLDCFXOXEN-UHFFFAOYSA-N 0.000 description 1
- JUJWROOIHBZHMG-UHFFFAOYSA-N Pyridine Chemical group C1=CC=NC=C1 JUJWROOIHBZHMG-UHFFFAOYSA-N 0.000 description 1
- 229910004298 SiO 2 Inorganic materials 0.000 description 1
- BLRPTPMANUNPDV-UHFFFAOYSA-N Silane Chemical compound [SiH4] BLRPTPMANUNPDV-UHFFFAOYSA-N 0.000 description 1
- 229910004166 TaN Inorganic materials 0.000 description 1
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 1
- NRTOMJZYCJJWKI-UHFFFAOYSA-N Titanium nitride Chemical compound [Ti]#N NRTOMJZYCJJWKI-UHFFFAOYSA-N 0.000 description 1
- 238000002441 X-ray diffraction Methods 0.000 description 1
- ZUQAPLKKNAQJAU-UHFFFAOYSA-N acetylenediol Chemical compound OC#CO ZUQAPLKKNAQJAU-UHFFFAOYSA-N 0.000 description 1
- 150000007513 acids Chemical class 0.000 description 1
- 238000005054 agglomeration Methods 0.000 description 1
- 230000004520 agglutination Effects 0.000 description 1
- 125000003172 aldehyde group Chemical group 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- 125000003342 alkenyl group Chemical group 0.000 description 1
- 150000003973 alkyl amines Chemical class 0.000 description 1
- 125000005907 alkyl ester group Chemical group 0.000 description 1
- 125000000217 alkyl group Chemical group 0.000 description 1
- XPCTZQVDEJYUGT-UHFFFAOYSA-N allomaltol Natural products CC=1OC=CC(=O)C=1O XPCTZQVDEJYUGT-UHFFFAOYSA-N 0.000 description 1
- HSFWRNGVRCDJHI-UHFFFAOYSA-N alpha-acetylene Natural products C#C HSFWRNGVRCDJHI-UHFFFAOYSA-N 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 125000003118 aryl group Chemical group 0.000 description 1
- HKVFISRIUUGTIB-UHFFFAOYSA-O azanium;cerium;nitrate Chemical compound [NH4+].[Ce].[O-][N+]([O-])=O HKVFISRIUUGTIB-UHFFFAOYSA-O 0.000 description 1
- 239000002585 base Substances 0.000 description 1
- 239000011324 bead Substances 0.000 description 1
- KGBXLFKZBHKPEV-UHFFFAOYSA-N boric acid Chemical compound OB(O)O KGBXLFKZBHKPEV-UHFFFAOYSA-N 0.000 description 1
- 239000004327 boric acid Substances 0.000 description 1
- 229910052796 boron Inorganic materials 0.000 description 1
- INAHAJYZKVIDIZ-UHFFFAOYSA-N boron carbide Chemical compound B12B3B4C32B41 INAHAJYZKVIDIZ-UHFFFAOYSA-N 0.000 description 1
- 239000005380 borophosphosilicate glass Substances 0.000 description 1
- 229910052794 bromium Inorganic materials 0.000 description 1
- 239000007853 buffer solution Substances 0.000 description 1
- AXCZMVOFGPJBDE-UHFFFAOYSA-L calcium dihydroxide Chemical compound [OH-].[OH-].[Ca+2] AXCZMVOFGPJBDE-UHFFFAOYSA-L 0.000 description 1
- 239000000920 calcium hydroxide Substances 0.000 description 1
- 229910001861 calcium hydroxide Inorganic materials 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 229910002092 carbon dioxide Inorganic materials 0.000 description 1
- 238000005119 centrifugation Methods 0.000 description 1
- 150000001785 cerium compounds Chemical class 0.000 description 1
- 229960001759 cerium oxalate Drugs 0.000 description 1
- VYLVYHXQOHJDJL-UHFFFAOYSA-K cerium trichloride Chemical compound Cl[Ce](Cl)Cl VYLVYHXQOHJDJL-UHFFFAOYSA-K 0.000 description 1
- ZMZNLKYXLARXFY-UHFFFAOYSA-H cerium(3+);oxalate Chemical compound [Ce+3].[Ce+3].[O-]C(=O)C([O-])=O.[O-]C(=O)C([O-])=O.[O-]C(=O)C([O-])=O ZMZNLKYXLARXFY-UHFFFAOYSA-H 0.000 description 1
- VGBWDOLBWVJTRZ-UHFFFAOYSA-K cerium(3+);triacetate Chemical compound [Ce+3].CC([O-])=O.CC([O-])=O.CC([O-])=O VGBWDOLBWVJTRZ-UHFFFAOYSA-K 0.000 description 1
- KHSBAWXKALEJFR-UHFFFAOYSA-H cerium(3+);tricarbonate;hydrate Chemical compound O.[Ce+3].[Ce+3].[O-]C([O-])=O.[O-]C([O-])=O.[O-]C([O-])=O KHSBAWXKALEJFR-UHFFFAOYSA-H 0.000 description 1
- KKVSNHQGJGJMHA-UHFFFAOYSA-H cerium(3+);trisulfate;hydrate Chemical compound O.[Ce+3].[Ce+3].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O KKVSNHQGJGJMHA-UHFFFAOYSA-H 0.000 description 1
- UNJPQTDTZAKTFK-UHFFFAOYSA-K cerium(iii) hydroxide Chemical compound [OH-].[OH-].[OH-].[Ce+3] UNJPQTDTZAKTFK-UHFFFAOYSA-K 0.000 description 1
- 238000003889 chemical engineering Methods 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 125000001309 chloro group Chemical group Cl* 0.000 description 1
- 239000011362 coarse particle Substances 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- PMHQVHHXPFUNSP-UHFFFAOYSA-M copper(1+);methylsulfanylmethane;bromide Chemical compound Br[Cu].CSC PMHQVHHXPFUNSP-UHFFFAOYSA-M 0.000 description 1
- 239000002178 crystalline material Substances 0.000 description 1
- 230000001186 cumulative effect Effects 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- BUMGIEFFCMBQDG-UHFFFAOYSA-N dichlorosilicon Chemical compound Cl[Si]Cl BUMGIEFFCMBQDG-UHFFFAOYSA-N 0.000 description 1
- 238000007865 diluting Methods 0.000 description 1
- 125000000118 dimethyl group Chemical group [H]C([H])([H])* 0.000 description 1
- 150000002009 diols Chemical class 0.000 description 1
- KZHJGOXRZJKJNY-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Si]=O.O=[Al]O[Al]=O.O=[Al]O[Al]=O.O=[Al]O[Al]=O KZHJGOXRZJKJNY-UHFFFAOYSA-N 0.000 description 1
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- Finish Polishing, Edge Sharpening, And Grinding By Specific Grinding Devices (AREA)
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Description
本発明は、ＣＭＰ用研磨液、及び、これを用いた研磨方法に関する。本発明は、例えば、半導体材料のケミカルメカニカルポリッシグ（ＣＭＰ）に使用するＣＭＰ用研磨液、及び、これを用いた研磨方法に関し、特に、半導体ウエハの表面に設けられた酸化ケイ素膜を研磨するためのＣＭＰ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 polishing liquid for CMP and a polishing method using the same. The present invention relates to, for example, a polishing liquid for CMP used for chemical mechanical polishing (CMP) of a semiconductor material and a polishing method using the same, and particularly polishes a silicon oxide film provided on the surface of a semiconductor wafer. The present invention relates to a polishing liquid for CMP for the purpose and a polishing method using the same.
半導体製造の分野では、超ＬＳＩデバイスの高性能化に伴い、従来技術の延長線上の微細化技術では高集積化及び高速化を両立することは限界になってきている。そこで、半導体素子の微細化を進めつつ、垂直方向にも高集積化する技術、すなわち、配線を多層化する技術が開発されている。 In the field of semiconductor manufacturing, as the performance of VLSI devices has improved, it has become a limit to achieve both high integration and high speed with miniaturization technology that is an extension of the conventional technology. Therefore, while advancing the miniaturization of semiconductor elements, a technique for highly integrating the semiconductor element in the vertical direction, that is, a technique for making the wiring multi-layered has been developed.
配線が多層化されたデバイスを製造するプロセスにおいて、最も重要な技術の一つにＣＭＰ技術がある。ＣＭＰ技術は、化学気相蒸着（ＣＶＤ）等によって基板上に薄膜を形成した後、その表面を平坦化する技術である。基板表面に凹凸があると、露光工程における焦点合わせが不可能となったり、微細な配線構造を充分に形成できなかったり等の不都合が生じる。ＣＭＰ技術は、デバイスの製造工程において、プラズマ酸化膜（ＢＰＳＧ、ＨＤＰ−ＳｉＯ２、ｐ−ＴＥＯＳ等）の研磨によって素子分離領域を形成する工程、層間絶縁膜を形成する工程、又は、酸化ケイ素を含む膜を金属配線に埋め込んだ後にプラグ（例えばＡｌ・Ｃｕプラグ）を平坦化する工程などにも適用される。 CMP technology is one of the most important technologies in the process of manufacturing a device having multiple layers of wiring. The CMP technique is a technique for forming a thin film on a substrate by chemical vapor deposition (CVD) or the like and then flattening the surface thereof. If the surface of the substrate is uneven, there are inconveniences such as the inability to focus in the exposure process and the inability to sufficiently form a fine wiring structure. CMP technology uses polishing of plasma oxide films (BPSG, HDP-SiO 2 , p-TEOS, etc.) to form element separation regions, interlayer insulating films, or silicon oxide in the device manufacturing process. It is also applied to a process of flattening a plug (for example, an Al / Cu plug) after embedding the containing film in a metal wiring.
ＣＭＰは、通常、研磨パッド上に研磨液を供給することができる装置を用いて行われる。基板表面と研磨パッドとの間に研磨液を供給しながら、基板を研磨パッドに押し付けることによって基板表面が研磨される。ＣＭＰ技術においては、高性能の研磨液が要素技術の一つであり、これまでにも種々の研磨液が開発されている（例えば、特許文献１を参照）。 CMP is usually performed using a device capable of supplying a polishing liquid onto the polishing pad. The surface of the substrate is polished by pressing the substrate against the polishing pad while supplying the polishing liquid between the surface of the substrate and the polishing pad. In the CMP technology, a high-performance polishing liquid is one of the elemental technologies, and various polishing liquids have been developed so far (see, for example, Patent Document 1).
ところで、基板上に素子分離領域を形成する工程においては、予め基板表面に溝を設け、この溝を埋めるように被研磨膜（例えば、酸化ケイ素膜等の絶縁膜）がＣＶＤ等によって形成される。その後、被研磨膜の表面をＣＭＰによって平坦化することによって素子分離領域が形成される。表面に凹部（溝）等の素子分離構造が設けられた基板上に被研磨膜を形成する場合、被研磨膜の表面にも、素子分離構造の凹凸に応じた凹凸が生じる。凹凸を有する表面に対しては、凸部が優先的に除去される一方、凹部がゆっくりと除去されることによって平坦化がなされる。 By the way, in the step of forming the element separation region on the substrate, a groove is provided in advance on the surface of the substrate, and a film to be polished (for example, an insulating film such as a silicon oxide film) is formed by CVD or the like so as to fill the groove. .. After that, the element separation region is formed by flattening the surface of the film to be polished by CMP. When the film to be polished is formed on a substrate provided with an element separation structure such as a recess (groove) on the surface, the surface of the film to be polished also has irregularities corresponding to the irregularities of the element separation structure. For a surface having irregularities, the convex portions are preferentially removed, while the concave portions are slowly removed to flatten the surface.
半導体生産のプロセスマージンや歩留まりを向上させるためには、基板上に形成した被研磨膜の不要な部分をウエハ面内で可能な限り均一に且つ高速に除去することが好ましい。例えば、素子分離領域の狭幅化に対応すべく、シャロー・トレンチ分離（ＳＴＩ）を採用した場合、基板上に設けた被研磨膜（例えば、酸化ケイ素膜等の絶縁膜）の段差や不要な部分を高い研磨速度で取り除くことが要求される。 In order to improve the process margin and yield of semiconductor production, it is preferable to remove unnecessary portions of the film to be polished formed on the substrate as uniformly and at high speed as possible in the wafer surface. For example, when shallow trench isolation (STI) is adopted in order to cope with the narrowing of the element separation region, a step or unnecessary step of the film to be polished (for example, an insulating film such as a silicon oxide film) provided on the substrate is used. It is required to remove the part at a high polishing rate.
しかし、酸化ケイ素膜に対する研磨速度が速いＣＭＰ用研磨液を用いると、一般に研磨終了後の研磨面が粗くなり、平坦性に劣る場合がある。このため、絶縁膜の研磨処理を二段階に分け、種類の異なる研磨液をそれぞれの工程で使用することによって、生産効率の向上を図る場合がある。第一の工程（荒削り工程）では酸化ケイ素膜に対する研磨速度が高い研磨液を使用して酸化ケイ素膜の大部分を除去する。第二の工程（仕上げ工程）では酸化ケイ素膜をゆっくりと除去し、研磨面が十分に平坦となるように仕上げる。 However, when a CMP polishing liquid having a high polishing rate for a silicon oxide film is used, the polished surface after polishing is generally roughened, and the flatness may be inferior. Therefore, the polishing process of the insulating film may be divided into two stages, and different types of polishing liquids may be used in each step to improve the production efficiency. In the first step (roughing step), most of the silicon oxide film is removed by using a polishing liquid having a high polishing rate for the silicon oxide film. In the second step (finishing step), the silicon oxide film is slowly removed to finish the polished surface so that it is sufficiently flat.
第一の工程においては、上記の通り、酸化ケイ素膜の高い研磨速度が要求される。しかし、同一の研磨液を使用した場合であっても基板表面の状態によって十分に高い研磨速度を達成できない場合がある。例えば、平坦な基板と、その表面に設けられた平坦な酸化ケイ素膜を備えるウエハ（酸化ケイ素膜のブランケットウエハ）を研磨する場合は酸化ケイ素膜の高い研磨速度を達成できるものの、表面に凹凸を有するウエハを研磨する場合には期待した研磨速度を達成できないことがある。なお、酸化ケイ素膜がＣＭＰによって研磨されるメカニズムについては未解明の部分が多く、このような現象の原因も明らかではない。 In the first step, as described above, a high polishing rate of the silicon oxide film is required. However, even when the same polishing liquid is used, a sufficiently high polishing rate may not be achieved depending on the condition of the surface of the substrate. For example, when polishing a flat substrate and a wafer having a flat silicon oxide film provided on the surface (a blanket wafer of a silicon oxide film), a high polishing rate of the silicon oxide film can be achieved, but the surface is uneven. When polishing a wafer to have, the expected polishing rate may not be achieved. The mechanism by which the silicon oxide film is polished by CMP has not been clarified in many parts, and the cause of such a phenomenon is not clear.
本発明は、前記課題を解決しようとするものであり、表面に凹凸を有するウエハにおいても高い研磨速度を有するＣＭＰ用研磨液、及び、これを用いた研磨方法を提供することを目的とする。 An object of the present invention is to solve the above problems, and an object of the present invention is to provide a polishing liquid for CMP having a high polishing rate even on a wafer having irregularities on the surface, and a polishing method using the polishing liquid.
本発明者らは、前記課題を解決すべく、ＣＭＰ用研磨液に配合する添加剤について鋭意検討を重ねた。本発明者らは、種々の化合物を添加剤として使用して研磨液を多数調製した。これらのＣＭＰ用研磨液を用いて、ブランケットウエハ、もしくは凹凸を有する被研磨膜（例えば、酸化ケイ素膜等の絶縁膜）を研磨し、研磨速度の評価を行った。その結果、４−ピロン系化合物又は４―ピリドン系化合物を使用することが、高い研磨速度を発揮することに有効であることを見出した。 In order to solve the above problems, the present inventors have made extensive studies on additives to be blended in the polishing liquid for CMP. The present inventors prepared a large number of polishing liquids using various compounds as additives. A blanket wafer or a film to be polished (for example, an insulating film such as a silicon oxide film) having irregularities was polished using these polishing solutions for CMP, and the polishing rate was evaluated. As a result, it was found that the use of a 4-pyrone compound or a 4-pyridone compound is effective in exhibiting a high polishing rate.
本発明に係るＣＭＰ用研磨液は、砥粒と、第一の添加剤と、水とを含有し、前記第一の添加剤が、下記一般式（１）で表される４−ピロン系化合物又は４―ピリドン系化合物である、ＣＭＰ用研磨液である。
［式中、Ｘ１１は、Ｏ又はＮＲを示し、Ｘ１２〜Ｘ１５及びＲは、それぞれ独立に水素原子又は１価の置換基を示す。］
The polishing liquid for CMP according to the present invention contains abrasive grains, a first additive, and water, and the first additive is a 4-pyrone compound represented by the following general formula (1). Alternatively, it is a polishing liquid for CMP, which is a 4-pyridone compound.
[In the formula, X 11 represents O or NR, and X 12 to X 15 and R each independently represent a hydrogen atom or a monovalent substituent. ]
本発明に係るＣＭＰ用研磨液によれば、凹凸を有する被研磨膜、もしくは凹凸を有しない被研磨膜（例えば、酸化ケイ素膜等の絶縁膜）を研磨した場合において高い研磨速度を達成できる。 According to the polishing liquid for CMP according to the present invention, a high polishing rate can be achieved when a film to be polished having irregularities or a film to be polished having no irregularities (for example, an insulating film such as a silicon oxide film) is polished.
これらの効果が奏される要因は必ずしも明らかではないが、特定の化学構造を有する第一の添加剤により、研磨液と被研磨膜（例えば、酸化ケイ素膜等の絶縁膜）との相互作用が大きくなり、その結果、研磨速度が高くなると推測される。 Although the factors that exert these effects are not always clear, the interaction between the polishing liquid and the film to be polished (for example, an insulating film such as a silicon oxide film) is caused by the first additive having a specific chemical structure. It is presumed that the polishing speed will increase as a result of the increase in size.
前記のとおり、本発明に係るＣＭＰ用研磨液は、凹凸を有する被研磨膜に対する高い研磨速度を達成できるため、凹凸を有する基板上に設けられた被研磨膜（例えば、酸化ケイ素膜等の絶縁膜）の研磨に適している。また、本発明に係るＣＭＰ用研磨液は、従来の研磨液では研磨速度を得ることが比較的困難な半導体材料であってもその効果を発揮できるという利点がある。例えば、メモリセルを有する半導体基板のように、上から見たときに凹部又は凸部がＴ字形状又は格子形状に設けられた部分を有する基板の被研磨膜（例えば、酸化ケイ素膜等の絶縁膜）を研磨する場合であってもその効果を発揮できる。 As described above, since the polishing liquid for CMP according to the present invention can achieve a high polishing rate for a film to be polished having irregularities, insulation of a film to be polished (for example, a silicon oxide film or the like) provided on a substrate having irregularities. Suitable for polishing film). Further, the polishing liquid for CMP according to the present invention has an advantage that the effect can be exhibited even if the semiconductor material is relatively difficult to obtain the polishing speed with the conventional polishing liquid. For example, an insulating film (for example, a silicon oxide film or the like) of a substrate having a portion in which concave portions or convex portions are provided in a T-shape or a lattice shape when viewed from above, such as a semiconductor substrate having a memory cell. The effect can be exhibited even when the film) is polished.
前記式（１）で表される４−ピロン系化合物又は４―ピリドン系化合物を含有する研磨液によれば、被研磨膜（例えば、酸化ケイ素膜等の絶縁膜）に対する充分に高い研磨速度を達成できるのに加えて、砥粒の凝集を抑制することができる。かかる効果が奏される要因は必ずしも明らかではないが、上述した特定構造を有する４−ピロン系化合物又は４―ピリドン系化合物は、研磨液と被研磨膜（例えば、酸化ケイ素膜等の絶縁膜）との相互作用を大きくし得る添加剤であるにも関わらず、砥粒同士の静電的反発力等の反発力を弱める効果がないため、砥粒の凝集を抑制することができると考えられる。 According to the polishing liquid containing the 4-pyrone compound or the 4-pyridone compound represented by the formula (1), a sufficiently high polishing rate for the film to be polished (for example, an insulating film such as a silicon oxide film) can be obtained. In addition to being achievable, agglomeration of abrasive grains can be suppressed. Although the factor for exerting such an effect is not always clear, the 4-pyrone compound or 4-pyridone compound having the above-mentioned specific structure is a polishing liquid and a film to be polished (for example, an insulating film such as a silicon oxide film). Although it is an additive that can increase the interaction with the abrasive grains, it does not have the effect of weakening the repulsive force such as the electrostatic repulsive force between the abrasive grains, so that it is considered that the aggregation of the abrasive grains can be suppressed. ..
前記第一の添加剤は、３―ヒドロキシ―１,２ジメチル４（１Ｈ）ピリドン、マルトールプロピオナート（３―ヒドロキシ―２―メチル―４―ピロンプロピオナート）及びデヒドロ酢酸からなる群より選ばれる少なくとも１種の化合物を含むことが好ましい。 The first additive is selected from the group consisting of 3-hydroxy-1,2dimethyl4 (1H) pyridone, maltol propionate (3-hydroxy-2-methyl-4-pyrone propionate) and dehydroacetic acid. It is preferable to contain at least one compound.
本発明に係るＣＭＰ用研磨液のｐＨは、８．０以下であることが好ましく、２．０〜５．０であることがより好ましい。 The pH of the polishing liquid for CMP according to the present invention is preferably 8.0 or less, and more preferably 2.0 to 5.0.
本発明に係るＣＭＰ用研磨液は、ｐＨ調整剤を更に含有してもよい。 The polishing liquid for CMP according to the present invention may further contain a pH adjuster.
本発明に係るＣＭＰ用研磨液は、表面に絶縁膜を有する基板を研磨するための研磨液であってもよい。 The polishing liquid for CMP according to the present invention may be a polishing liquid for polishing a substrate having an insulating film on the surface.
前記第一の添加剤の含有量は、当該研磨液１００質量部に対して０．００１〜５質量部であることが好ましい。かかる構成を採用することにより、研磨速度の向上効果が更に効率的に得られる。 The content of the first additive is preferably 0.001 to 5 parts by mass with respect to 100 parts by mass of the polishing liquid. By adopting such a configuration, the effect of improving the polishing speed can be obtained more efficiently.
前記砥粒の含有量は、当該研磨液１００質量部に対して０．１〜１０質量部であることが好ましい。 The content of the abrasive grains is preferably 0.1 to 10 parts by mass with respect to 100 parts by mass of the polishing liquid.
前記砥粒の平均粒径は、５０〜５００ｎｍであることが好ましい。前記砥粒は、セリウム系化合物を含むことが好ましい。前記セリウム系化合物は、酸化セリウムであることが好ましい。前記砥粒は、結晶粒界を有する多結晶酸化セリウムを含むことが好ましい。砥粒に関するこれらの構成のうち、１つの構成又は２つ以上の構成を採用することにより、被研磨膜（例えば、酸化ケイ素膜等の絶縁膜）の研磨速度が更に向上する。 The average particle size of the abrasive grains is preferably 50 to 500 nm. The abrasive grains preferably contain a cerium-based compound. The cerium-based compound is preferably cerium oxide. The abrasive grains preferably contain polycrystalline cerium oxide having grain boundaries. By adopting one configuration or two or more configurations among these configurations relating to the abrasive grains, the polishing speed of the film to be polished (for example, an insulating film such as a silicon oxide film) is further improved.
本発明に係るＣＭＰ用研磨液は、非イオン性界面活性剤を更に含有してもよい。かかる構成を採用することにより、研磨液中の砥粒の分散安定性が向上する。 The polishing liquid for CMP according to the present invention may further contain a nonionic surfactant. By adopting such a configuration, the dispersion stability of the abrasive grains in the polishing liquid is improved.
本発明に係るＣＭＰ用研磨液は、第二の添加剤として飽和モノカルボン酸を更に含有することが好ましい。かかる構成を採用することにより、凹凸形状を有する半導体基板の研磨速度を低下させることなく、平坦な半導体基板の研磨速度を向上させる利点、研磨速度のウエハ面内のばらつきの指標である面内均一性を向上させる利点等が得られる。 The polishing liquid for CMP according to the present invention preferably further contains a saturated monocarboxylic acid as a second additive. By adopting such a configuration, there is an advantage of improving the polishing speed of a flat semiconductor substrate without lowering the polishing speed of a semiconductor substrate having an uneven shape, and in-plane uniformity which is an index of variation in the polishing speed in the wafer surface. The advantage of improving the property can be obtained.
前記飽和モノカルボン酸の炭素数は、２〜６であることが好ましい。かかる構成を採用することにより、平坦な半導体基板の研磨速度の向上効果及び面内均一性の向上効果が更に良好に得られる。 The saturated monocarboxylic acid preferably has 2 to 6 carbon atoms. By adopting such a configuration, the effect of improving the polishing speed of the flat semiconductor substrate and the effect of improving the in-plane uniformity can be further satisfactorily obtained.
前記飽和モノカルボン酸は、酢酸、プロピオン酸、酪酸、イソ酪酸、吉草酸、イソ吉草酸、ピバル酸、ヒドロアンゲリカ酸、カプロン酸、２−メチルペンタン酸、４−メチルペンタン酸、２，３ジメチルブタン酸、２−エチルブタン酸、２，２−ジメチルブタン酸及び３，３−ジメチルブタン酸からなる群より選ばれる少なくとも１種の化合物であることが好ましい。 The saturated monocarboxylic acids include acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, isovaleric acid, pivalic acid, hydroangelica acid, caproic acid, 2-methylpentanoic acid, 4-methylpentanoic acid, and 2,3 dimethyl. It is preferably at least one compound selected from the group consisting of butanoic acid, 2-ethylbutanoic acid, 2,2-dimethylbutanoic acid and 3,3-dimethylbutanoic acid.
前記飽和モノカルボン酸の含有量は、当該研磨液１００質量部に対して０．０１〜１０質量部であることが好ましい。かかる構成を採用することにより、平坦な半導体基板の研磨速度の向上効果及び面内均一性の向上効果が更に効率的に得られる。 The content of the saturated monocarboxylic acid is preferably 0.01 to 10 parts by mass with respect to 100 parts by mass of the polishing liquid. By adopting such a configuration, the effect of improving the polishing speed of the flat semiconductor substrate and the effect of improving the in-plane uniformity can be obtained more efficiently.
本発明は、前記研磨液を用いた研磨方法を提供する。すなわち、本発明に係る研磨方法は、表面に絶縁膜を有する基板を研磨する研磨方法であって、前記ＣＭＰ用研磨液を前記絶縁膜と研磨パッドとの間に供給しながら、前記研磨パッドによって前記絶縁膜の研磨を行う工程を備える。この研磨方法によれば、絶縁膜（酸化ケイ素膜等）に対する充分に高い研磨速度を達成できる。また、高い研磨速度は、研磨対象の基板の表面形状に大きく依存することなく達成されるため、この研磨方法は、絶縁膜（酸化ケイ素膜等）の荒削りや、メモリセルを有する半導体基板（例えば、上から見たときに凹部又は凸部がＴ字形状又は格子形状に設けられた部分を有する基板）の研磨に適している。 The present invention provides a polishing method using the polishing liquid. That is, the polishing method according to the present invention is a polishing method for polishing a substrate having an insulating film on the surface, and while supplying the polishing liquid for CMP between the insulating film and the polishing pad, the polishing pad is used. The step of polishing the insulating film is provided. According to this polishing method, a sufficiently high polishing rate for an insulating film (silicon oxide film or the like) can be achieved. Further, since a high polishing rate can be achieved without greatly depending on the surface shape of the substrate to be polished, this polishing method can be used for rough cutting of an insulating film (silicon oxide film, etc.) or a semiconductor substrate having a memory cell (for example,). It is suitable for polishing a substrate having a portion in which a concave portion or a convex portion is provided in a T-shape or a lattice shape when viewed from above.
本発明によれば、表面に凹凸を有するウエハにおいても高い研磨速度を有するＣＭＰ用研磨液を提供することができる。より具体的には、本発明によれば、酸化ケイ素膜に対する十分に高い研磨速度を達成できると共に、従来の研磨液と比較して基板表面の状態に依存しない（表面の凹凸の有無に関わらず優れた研磨速度を有する）汎用性の高いＣＭＰ用研磨液が提供される。また、本発明によれば、上記研磨液を用いた研磨方法が提供される。 According to the present invention, it is possible to provide a polishing liquid for CMP having a high polishing rate even on a wafer having an uneven surface. More specifically, according to the present invention, it is possible to achieve a sufficiently high polishing rate for the silicon oxide film, and it does not depend on the state of the substrate surface as compared with the conventional polishing liquid (regardless of the presence or absence of surface irregularities). A versatile polishing liquid for CMP (having an excellent polishing rate) is provided. Further, according to the present invention, a polishing method using the above-mentioned polishing liquid is provided.
以下、本発明の実施形態について詳細に説明する。 Hereinafter, embodiments of the present invention will be described in detail.
＜ＣＭＰ用研磨液＞
本実施形態に係るＣＭＰ用研磨液は、砥粒（研磨粒子）と、第一の添加剤と、水とを含有し、前記第一の添加剤が、４−ピロン系化合物又は４―ピリドン系化合物を含むことを特徴とする。本実施形態に係るＣＭＰ用研磨液によれば、従来の研磨液と比較して基板表面の状態に依存することなく、被研磨膜（例えば、酸化ケイ素膜等の絶縁膜）に対する十分に高い研磨速度を達成することができる。以下、研磨液の調製に使用する各成分等について説明する。
<Abrasive liquid for CMP>
The polishing liquid for CMP according to the present embodiment contains abrasive grains (polishing particles), a first additive, and water, and the first additive is a 4-pyrone compound or a 4-pyridone compound. It is characterized by containing a compound. According to the polishing liquid for CMP according to the present embodiment, the polishing of the film to be polished (for example, an insulating film such as a silicon oxide film) is sufficiently high as compared with the conventional polishing liquid, without depending on the state of the substrate surface. Speed can be achieved. Hereinafter, each component and the like used for preparing the polishing liquid will be described.
（砥粒）
砥粒は、例えば、セリウム系化合物、アルミナ、シリカ、チタニア、ジルコニア、マグネシア、ムライト、窒化ケイ素、α−サイアロン、窒化アルミニウム、窒化チタン、炭化ケイ素、炭化ホウ素等を含むことができる。これらの砥粒の構成成分としては、１種を単独で用いてもよく、２種以上を併用してもよい。これらの中でも、第一の添加剤の添加効果を更に良好に発揮でき、凹凸を有する被研磨膜（例えば、酸化ケイ素膜等の絶縁膜）に対する高い研磨速度が更に高度に得られる観点から、セリウム系化合物が好ましい。
(Abrasive grain)
Abrasive grains can include, for example, cerium compounds, alumina, silica, titania, zirconia, magnesia, mullite, silicon nitride, α-sialon, aluminum nitride, titanium nitride, silicon carbide, boron carbide and the like. As the constituent components of these abrasive grains, one type may be used alone, or two or more types may be used in combination. Among these, cerium can exert the effect of adding the first additive more satisfactorily, and can obtain a higher polishing rate for a film to be polished (for example, an insulating film such as a silicon oxide film) having irregularities. Based compounds are preferred.
セリウム系化合物を含む砥粒を用いたＣＭＰ用研磨液は、被研磨面に生じる研磨傷が比較的少ないという特長を有する。従来、被研磨膜（例えば、酸化ケイ素膜等の絶縁膜）に対する高い研磨速度を達成し易い観点から、砥粒としてシリカ粒子を含むＣＭＰ用研磨液が広く用いられている。しかし、シリカ粒子を用いたＣＭＰ用研磨液は、一般に被研磨面に研磨傷が生じ易いという課題がある。配線幅が４５ｎｍ世代以降の微細パターンを有するデバイスにおいては、従来問題にならなかったような微細な傷であっても、デバイスの信頼性に影響するおそれがある。 A polishing liquid for CMP using abrasive grains containing a cerium-based compound has a feature that there are relatively few polishing scratches on the surface to be polished. Conventionally, a CMP polishing liquid containing silica particles as abrasive grains has been widely used from the viewpoint of easily achieving a high polishing rate for a film to be polished (for example, an insulating film such as a silicon oxide film). However, the polishing liquid for CMP using silica particles generally has a problem that polishing scratches are likely to occur on the surface to be polished. In a device having a fine pattern with a wiring width of 45 nm or later, even fine scratches that have not been a problem in the past may affect the reliability of the device.
セリウム系化合物としては、例えば、酸化セリウム、セリウム水酸化物、硝酸アンモニウムセリウム、酢酸セリウム、硫酸セリウム水和物、臭素酸セリウム、臭化セリウム、塩化セリウム、シュウ酸セリウム、硝酸セリウム、炭酸セリウム等が挙げられる。これらの中でも、酸化セリウムが好ましい。酸化セリウムを使用することで、高い研磨速度を更に高度に両立できると共に、研磨傷が少ない優れた被研磨面が得られる。 Examples of the cerium-based compound include cerium oxide, cerium hydroxide, ammonium cerium nitrate, cerium acetate, cerium sulfate hydrate, cerium bromide, cerium bromide, cerium chloride, cerium oxalate, cerium nitrate, cerium carbonate and the like. Can be mentioned. Among these, cerium oxide is preferable. By using cerium oxide, a high polishing rate can be achieved at a higher level, and an excellent surface to be polished with few polishing scratches can be obtained.
酸化セリウムを使用する場合、砥粒は、結晶粒界を有する多結晶酸化セリウム（例えば、結晶粒界に囲まれた複数の結晶子を有する多結晶酸化セリウム）を含むことが好ましい。かかる構成の多結晶酸化セリウム粒子は、単結晶粒子が凝集した単なる凝集体とは異なっており、研磨中の応力により細かくなると同時に、活性面（細かくなる前は外部にさらされていない面）が次々と現れるため、被研磨膜（例えば、酸化ケイ素膜等の絶縁膜）に対する高い研磨速度を高度に維持できると考えられる。このような多結晶酸化セリウム粒子については、例えば、国際公開公報ＷＯ９９／３１１９５号に詳しく説明されている。 When cerium oxide is used, the abrasive grains preferably contain polycrystalline cerium oxide having grain boundaries (for example, polycrystalline cerium having a plurality of crystallites surrounded by grain boundaries). The polycrystalline cerium oxide particles having such a structure are different from simple aggregates in which single crystal particles are aggregated, and at the same time, they become finer due to stress during polishing, and at the same time, the active surface (the surface that is not exposed to the outside before becoming finer) becomes finer. Since it appears one after another, it is considered that a high polishing rate for the film to be polished (for example, an insulating film such as a silicon oxide film) can be maintained at a high level. Such polycrystalline cerium oxide particles are described in detail in, for example, WO99 / 31195.
酸化セリウムを含む砥粒の製造方法としては、特に制限はないが、液相合成；焼成又は過酸化水素等により酸化する方法などが挙げられる。前記結晶粒界を有する多結晶酸化セリウムを含む砥粒を得る場合には、炭酸セリウム等のセリウム源を焼成する方法が好ましい。前記焼成時の温度は、３５０〜９００℃が好ましい。製造された酸化セリウム粒子が凝集している場合は、機械的に粉砕することが好ましい。粉砕方法としては、特に制限はないが、例えば、ジェットミル等による乾式粉砕；遊星ビーズミル等による湿式粉砕が好ましい。ジェットミルは、例えば、「化学工学論文集」、第６巻、第５号、（１９８０）、５２７〜５３２頁に説明されている。 The method for producing abrasive grains containing cerium oxide is not particularly limited, and examples thereof include liquid phase synthesis; a method of oxidizing by firing or hydrogen peroxide or the like. When obtaining abrasive grains containing polycrystalline cerium oxide having grain boundaries, a method of firing a cerium source such as cerium carbonate is preferable. The temperature at the time of firing is preferably 350 to 900 ° C. When the produced cerium oxide particles are agglomerated, it is preferable to pulverize them mechanically. The pulverization method is not particularly limited, but for example, dry pulverization by a jet mill or the like; wet pulverization by a planetary bead mill or the like is preferable. Jet mills are described, for example, in "Chemical Engineering Proceedings," Vol. 6, No. 5, (1980), pp. 527-532.
砥粒の平均粒径は、５０ｎｍ以上が好ましく、７０ｎｍ以上がより好ましく、８０ｎｍ以上が更に好ましい。平均粒径が５０ｎｍ以上であると、５０ｎｍ未満の場合と比較して被研磨膜（例えば、酸化ケイ素膜等の絶縁膜）の研磨速度を高くできる。砥粒の平均粒径は、５００ｎｍ以下が好ましく、３００ｎｍ以下がより好ましく、２８０ｎｍ以下が更に好ましく、２５０ｎｍ以下が特に好ましく、２００ｎｍ以下が極めて好ましい。平均粒径が５００ｎｍ以下であると、５００ｎｍを超える場合と比較して研磨傷を抑制できる。砥粒の平均粒径を制御するためには、従来公知の方法を使用することができ、前記酸化セリウム粒子を例にすると、前記焼成温度、焼成時間、粉砕条件等の制御；濾過、分級等の適用などが挙げられる。 The average particle size of the abrasive grains is preferably 50 nm or more, more preferably 70 nm or more, and even more preferably 80 nm or more. When the average particle size is 50 nm or more, the polishing rate of the film to be polished (for example, an insulating film such as a silicon oxide film) can be increased as compared with the case where the average particle size is less than 50 nm. The average particle size of the abrasive grains is preferably 500 nm or less, more preferably 300 nm or less, further preferably 280 nm or less, particularly preferably 250 nm or less, and extremely preferably 200 nm or less. When the average particle size is 500 nm or less, polishing scratches can be suppressed as compared with the case where the average particle size exceeds 500 nm. In order to control the average particle size of the abrasive grains, a conventionally known method can be used. Taking the cerium oxide particles as an example, control of the firing temperature, firing time, crushing conditions, etc.; filtration, classification, etc. The application of.
ここでいう砥粒の平均粒径は砥粒のＤ５０％粒子径を意味する。「砥粒のＤ５０％粒子径」とは、砥粒が分散した研磨液サンプルを散乱式粒度分布計で測定した体積分布の中央値を意味する。具体的には、株式会社堀場製作所製のＬＡ−９２０（商品名）等を用いて測定される値である。砥粒の含有量が研磨液サンプル１００質量部に対して０．５質量部になるように研磨液サンプルの砥粒の含有量を調整し、これをＬＡ−９２０にセットして体積分布の中央値の測定を行う。なお、ＬＡ−９２０によってメジアン径（累積中央値）を測定することによって、砥粒の凝集の程度を評価することもできる。ＣＭＰ用研磨液中の砥粒の平均粒径を測定する場合は、前記ＣＭＰ用研磨液を濃縮又は水で希釈することによって砥粒の含有量が研磨液サンプル１００質量部に対して０．５質量部になるように研磨液サンプルの砥粒の含有量を調整してから、同様の方法で測定することができる。 The average particle size of the abrasive grains here means the D50% particle size of the abrasive grains. The "D50% particle size of abrasive grains" means the median value of the volume distribution of the polishing liquid sample in which the abrasive grains are dispersed measured by a scattering type particle size distribution meter. Specifically, it is a value measured using LA-920 (trade name) manufactured by HORIBA, Ltd. Adjust the content of abrasive grains in the polishing liquid sample so that the content of abrasive grains is 0.5 parts by mass with respect to 100 parts by mass of the polishing liquid sample, set this in LA-920, and set it in the center of the volume distribution. Measure the value. The degree of aggregation of abrasive grains can also be evaluated by measuring the median diameter (cumulative median value) with LA-920. When measuring the average particle size of the abrasive grains in the CMP polishing solution, the content of the abrasive grains is 0.5 with respect to 100 parts by mass of the polishing solution sample by concentrating or diluting the CMP polishing solution with water. After adjusting the content of abrasive grains in the polishing liquid sample so as to be parts by mass, the measurement can be performed by the same method.
砥粒の含有量（粒子含有量）は、ＣＭＰ用研磨液１００質量部に対して、０．１質量部以上が好ましく、０．１５質量部以上がより好ましく、０．２質量部以上が更に好ましい。砥粒の含有量が０．１質量部以上であると、０．１質量部未満の場合と比較して高い研磨速度が達成される傾向がある。砥粒の含有量は、ＣＭＰ用研磨液１００質量部に対して、１０質量部以下が好ましく、５．０質量部以下がより好ましく、３．０質量部以下が更に好ましく、２．０質量部以下が特に好ましく、１．０質量部以下が極めて好ましい。砥粒の含有量が１０質量部以下であると、１０質量部を超える場合と比較して砥粒の凝集を抑制し易く、高い研磨速度を達成し易い傾向がある。 The content of abrasive grains (particle content) is preferably 0.1 part by mass or more, more preferably 0.15 parts by mass or more, and further more preferably 0.2 parts by mass or more with respect to 100 parts by mass of the polishing liquid for CMP. preferable. When the content of the abrasive grains is 0.1 parts by mass or more, a higher polishing rate tends to be achieved as compared with the case where the content is less than 0.1 parts by mass. The content of abrasive grains is preferably 10 parts by mass or less, more preferably 5.0 parts by mass or less, further preferably 3.0 parts by mass or less, and 2.0 parts by mass with respect to 100 parts by mass of the polishing liquid for CMP. The following is particularly preferable, and 1.0 part by mass or less is extremely preferable. When the content of the abrasive grains is 10 parts by mass or less, it is easy to suppress the aggregation of the abrasive grains as compared with the case where it exceeds 10 parts by mass, and it tends to be easy to achieve a high polishing rate.
（第一の添加剤）
第一の添加剤は、下記一般式（１）で表される４−ピロン系化合物及び４―ピリドン系化合物の中から１種又は２種以上を含む。
The first additive contains one or more of a 4-pyrone compound and a 4-pyridone compound represented by the following general formula (1).
式（１）中、Ｘ１１は、Ｏ（酸素原子）又はＮ（窒素原子）Ｒを示し、Ｘ１２〜Ｘ１５及びＲは、それぞれ独立に水素原子又は１価の置換基を示す。１価の置換基としては、カルボニル基、エステル基、アルデヒド基、ヒドロキシ基（水酸基）、オキシ基、カルボキシル基、スルホン酸基、リン酸基、臭素原子、塩素原子、ヨウ素原子、フッ素原子、ニトロ基、ヒドラジン基、炭素数１〜８のアルキル基（ＯＨ、ＣＯＯＨ、Ｂｒ、Ｃｌ、Ｉ又はＮＯ２で置換されていてもよい）、炭素数６〜１２のアリール基、炭素数１〜８のアルケニル基等が挙げられる。 In formula (1), X 11 represents O (oxygen atom) or N (nitrogen atom) R, and X 12 to X 15 and R each independently represent a hydrogen atom or a monovalent substituent. The monovalent substituent includes a carbonyl group, an ester group, an aldehyde group, a hydroxy group (hydroxyl group), an oxy group, a carboxyl group, a sulfonic acid group, a phosphoric acid group, a bromine atom, a chlorine atom, an iodine atom, a fluorine atom, and a nitro group. Group, hydrazine group, alkyl group having 1 to 8 carbon atoms ( may be substituted with OH, COOH, Br, Cl, I or NO 2 ), aryl group having 6 to 12 carbon atoms, having 1 to 8 carbon atoms. Examples thereof include an alkenyl group.
前記４−ピロン系化合物又は４―ピリドン系化合物が、Ｘ１２〜Ｘ１５として１価の置換基を有する場合、合成が簡易である観点から、Ｘ１２及びＸ１５の少なくとも一方が１価の置換基であることが好ましい。更に、砥粒の研磨能力の向上効果が得られ易い観点から、Ｘ１２〜Ｘ１５のうち少なくとも１つは水素原子であることが好ましい。 Substituted the 4-pyrone compound or 4-pyridone compounds, if having a monovalent substituent as X 12 to X 15, a synthetic is simple aspect, at least one of X 12 and X 15 is a monovalent It is preferably a group. Further, from the viewpoint that the effect of improving the polishing ability of the abrasive grains can be easily obtained, it is preferable that at least one of X 12 to X 15 is a hydrogen atom.
前記４−ピロン系化合物又は４―ピリドン系化合物は、少なくともカルボニル基の炭素原子に隣接している炭素原子にヒドロキシ基が結合した構造を有する。ここで、「４−ピロン系化合物」とは、オキシ基及びカルボニル基が含まれると共に、オキシ基に対してカルボニル基が４位に位置している６員環（γ−ピロン環）構造を有する複素環式化合物である。また、「４―ピリドン系化合物」とは、ピリジン環の４位にカルボニル基が位置している６員環（γ−ピリドン環）構造を有する複素環式化合物である。 The 4-pyrone compound or 4-pyridone compound has a structure in which a hydroxy group is bonded to a carbon atom adjacent to at least the carbon atom of the carbonyl group. Here, the "4-pyrone compound" has a 6-membered ring (γ-pyrone ring) structure containing an oxy group and a carbonyl group and having a carbonyl group located at the 4-position with respect to the oxy group. It is a heterocyclic compound. The "4-pyridone compound" is a heterocyclic compound having a 6-membered ring (γ-pyridone ring) structure in which a carbonyl group is located at the 4-position of the pyridine ring.
このような４−ピロン系化合物又は４―ピリドン系化合物としては、高い研磨速度を達成する効果が更に好適に得られる観点から、３―ヒドロキシ―１,２ジメチル４（１Ｈ）ピリドン、マルトールプロピオナート（３―ヒドロキシ―２―メチル―４―ピロンプロピオナート）及びデヒドロ酢酸からなる群より選ばれる少なくとも１種の化合物が好ましい。 As such a 4-pyrone compound or a 4-pyridone compound, 3-hydroxy-1,2 dimethyl 4 (1H) pyridone and maltol propio are used from the viewpoint of more preferably obtaining the effect of achieving a high polishing rate. At least one compound selected from the group consisting of nalto (3-hydroxy-2-methyl-4-pyrone propionate) and dehydroacetic acid is preferred.
第一の添加剤としては、１種を単独で用いてもよく、２種以上を併用してもよい。第一の添加剤を２種以上組み合わせて使用することによっても高い研磨速度が得られる。 As the first additive, one type may be used alone, or two or more types may be used in combination. A high polishing rate can also be obtained by using two or more kinds of the first additives in combination.
第一の添加剤は、水溶性であることが好ましい。水への溶解度が高い化合物を使用することにより、所望の量の第一の添加剤を良好にＣＭＰ用研磨液中に溶解させることができ、研磨速度の向上効果、及び、砥粒の凝集の抑制効果をより一層高水準に達成することができる。室温（２５℃）の水１００ｇに対する第一の添加剤の溶解度は、０．００１ｇ以上が好ましく、０．００５ｇ以上がより好ましく、０．０１ｇ以上が更に好ましく、０．０５ｇ以上が特に好ましい。なお、溶解度の上限は特に制限はない。 The first additive is preferably water soluble. By using a compound having high solubility in water, a desired amount of the first additive can be satisfactorily dissolved in the polishing liquid for CMP, and the effect of improving the polishing speed and the aggregation of abrasive grains can be achieved. The inhibitory effect can be achieved to a higher level. The solubility of the first additive in 100 g of water at room temperature (25 ° C.) is preferably 0.001 g or more, more preferably 0.005 g or more, further preferably 0.01 g or more, and particularly preferably 0.05 g or more. The upper limit of solubility is not particularly limited.
第一の添加剤の含有量は、ＣＭＰ用研磨液１００質量部に対して、０．００１質量部以上が好ましく、０．００３質量部以上がより好ましく、０．００５質量部以上が更に好ましい。第一の添加剤の含有量が０．００１質量部以上であると、０．００１質量部未満の場合と比較して安定した研磨速度を達成し易い傾向がある。第一の添加剤の含有量は、ＣＭＰ用研磨液１００質量部に対して、５質量部以下が好ましく、３質量部以下がより好ましく、１質量部以下が更に好ましく、０．５質量部以下が特に好ましい。第一の添加剤の含有量が５質量部以下であると、５質量部を超える場合と比較して、砥粒の凝集を抑制し易く、高い研磨速度を達成し易い傾向がある。 The content of the first additive is preferably 0.001 part by mass or more, more preferably 0.003 part by mass or more, and further preferably 0.005 part by mass or more with respect to 100 parts by mass of the polishing liquid for CMP. When the content of the first additive is 0.001 part by mass or more, a stable polishing rate tends to be easily achieved as compared with the case where the content is less than 0.001 part by mass. The content of the first additive is preferably 5 parts by mass or less, more preferably 3 parts by mass or less, further preferably 1 part by mass or less, and 0.5 parts by mass or less with respect to 100 parts by mass of the polishing liquid for CMP. Is particularly preferable. When the content of the first additive is 5 parts by mass or less, it tends to be easier to suppress the aggregation of abrasive grains and to easily achieve a high polishing rate as compared with the case where it exceeds 5 parts by mass.
（水）
本実施形態に係るＣＭＰ用研磨液が含有する水は、特に制限されるものではないが、脱イオン水、イオン交換水及び超純水が好ましい。なお、必要に応じて、エタノール、アセトン等の極性溶媒などを水と併用してもよい。
(water)
The water contained in the CMP polishing liquid according to the present embodiment is not particularly limited, but deionized water, ion-exchanged water, and ultrapure water are preferable. If necessary, a polar solvent such as ethanol or acetone may be used in combination with water.
（第二の添加剤）
本実施形態に係るＣＭＰ用研磨液は、第二の添加剤として、飽和モノカルボン酸を含有することが好ましい。これにより、凹凸のないウエハ（ブランケットウエハ）の研磨速度を向上させ、また面内均一性を向上させることができる。一般に、凹凸を有するウエハの研磨では、凸部が優先的に研磨されるために研磨が進行するに従い被研磨面がブランケットウエハの状態に近づく傾向がある。そのため、ブランケットウエハの研磨速度にも優れる研磨液は、全工程を通じて良好な研磨速度が得られる点で好適である。
(Second additive)
The CMP polishing liquid according to the present embodiment preferably contains a saturated monocarboxylic acid as a second additive. As a result, the polishing speed of a wafer (blanket wafer) having no unevenness can be improved, and the in-plane uniformity can be improved. In general, in polishing a wafer having irregularities, since the convex portions are preferentially polished, the surface to be polished tends to approach the state of a blanket wafer as the polishing progresses. Therefore, a polishing liquid having an excellent polishing rate for the blanket wafer is suitable in that a good polishing rate can be obtained throughout the entire process.
前記の観点から、飽和モノカルボン酸の炭素数は、２〜６であることが好ましい。飽和モノカルボン酸としては、例えば、酢酸、プロピオン酸、酪酸、イソ酪酸、吉草酸、イソ吉草酸、ピバル酸、ヒドロアンゲリカ酸、カプロン酸、２−メチルペンタン酸、４−メチルペンタン酸、２，３−ジメチルブタン酸、２−エチルブタン酸、２，２−ジメチルブタン酸及び３，３−ジメチルブタン酸等が好ましい。なお、飽和モノカルボン酸としては、これらの化合物のうちの１種を単独で用いてもよく、２種以上を組み合わせて用いてもよい。 From the above viewpoint, the saturated monocarboxylic acid preferably has 2 to 6 carbon atoms. Saturated monocarboxylic acids include, for example, acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, isovaleric acid, pivalic acid, hydroangelica acid, caproic acid, 2-methylpentanoic acid, 4-methylpentanoic acid, 2, 3-Dimethylbutanoic acid, 2-ethylbutanoic acid, 2,2-dimethylbutanoic acid, 3,3-dimethylbutanoic acid and the like are preferable. As the saturated monocarboxylic acid, one of these compounds may be used alone, or two or more thereof may be used in combination.
第二の添加剤として飽和モノカルボン酸を使用する場合、第二の添加剤の含有量は、ＣＭＰ用研磨液１００質量部に対して、０．０１質量部以上が好ましく、０．０５質量部以上がより好ましく、０．０７５質量部以上が更に好ましく、０．０９質量部以上が特に好ましい。第二の添加剤の含有量が０．０１質量部以上であると、安定した研磨速度及び良好な面内均一性が達成され易い。第二の添加剤の含有量は、ＣＭＰ用研磨液１００質量部に対して、１０質量部以下が好ましく、５質量部以下がより好ましく、３質量部以下が更に好ましく、２質量部以下が特に好ましく、１質量部以下が極めて好ましい。第二の添加剤の含有量が１０質量部以下であると、１０質量部を超える場合と比較して、砥粒の凝集を抑制し易く、安定した研磨速度及び良好な面内均一性が達成され易い。 When a saturated monocarboxylic acid is used as the second additive, the content of the second additive is preferably 0.01 part by mass or more, preferably 0.05 part by mass with respect to 100 parts by mass of the polishing liquid for CMP. The above is more preferable, 0.075 parts by mass or more is further preferable, and 0.09 parts by mass or more is particularly preferable. When the content of the second additive is 0.01 parts by mass or more, stable polishing rate and good in-plane uniformity are likely to be achieved. The content of the second additive is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, further preferably 3 parts by mass or less, and particularly preferably 2 parts by mass or less, based on 100 parts by mass of the polishing liquid for CMP. Preferably, it is 1 part by mass or less, which is extremely preferable. When the content of the second additive is 10 parts by mass or less, it is easier to suppress the aggregation of abrasive grains as compared with the case where it exceeds 10 parts by mass, and a stable polishing rate and good in-plane uniformity are achieved. Easy to do.
（他の成分）
本実施形態に係るＣＭＰ用研磨液は、砥粒の分散安定性及び／又は被研磨面の平坦性を向上させる観点から、界面活性剤を含有することができる。界面活性剤としては、イオン性界面活性剤、非イオン性界面活性剤等が挙げられ、非イオン性界面活性剤が好ましい。界面活性剤としては、１種を単独で用いてもよく、２種以上を併用してもよい。
(Other ingredients)
The polishing liquid for CMP according to the present embodiment may contain a surfactant from the viewpoint of improving the dispersion stability of the abrasive grains and / or the flatness of the surface to be polished. Examples of the surfactant include an ionic surfactant and a nonionic surfactant, and a nonionic surfactant is preferable. As the surfactant, one type may be used alone, or two or more types may be used in combination.
非イオン性界面活性剤として、ポリオキシプロピレンポリオキシエチレンアルキルエーテル、ポリオキシエチレンアルキルエーテル、ポリオキシエチレンアルキルアリルエーテル、ポリオキシエチレンポリオキシプロピレンエーテル誘導体、ポリオキシプロピレングリセリルエーテル、ポリエチレングリコールのオキシエチレン付加体、メトキシポリエチレングリコールのオキシエチレン付加体、アセチレン系ジオールのオキシエチレン付加体等のエーテル型界面活性剤；ソルビタン脂肪酸エステル、グリセロールボレイト脂肪酸エステル等のエステル型界面活性剤；ポリオキシエチレンアルキルアミン等のアミノエーテル型界面活性剤；ポリオキシエチレンソルビタン脂肪酸エステル、ポリオキシエチレングリセロールボレイト脂肪酸エステル、ポリオキシエチレンアルキルエステル等のエーテルエステル型界面活性剤；脂肪酸アルカノールアミド、ポリオキシエチレン脂肪酸アルカノールアミド等のアルカノールアミド型界面活性剤；アセチレン系ジオールのオキシエチレン付加体；ポリビニルピロリドン；ポリアクリルアミド；ポリジメチルアクリルアミド；ポリビニルアルコールなどが挙げられる。非イオン性界面活性剤としては、１種を単独で用いてもよく、２種以上を併用してもよい。 As nonionic surfactants, polyoxypropylene polyoxyethylene alkyl ether, polyoxyethylene alkyl ether, polyoxyethylene alkyl allyl ether, polyoxyethylene polyoxypropylene ether derivative, polyoxypropylene glyceryl ether, polyethylene glycol oxyethylene Ether-type surfactants such as adducts, oxyethylene adducts of methoxypolyethylene glycol, and oxyethylene adducts of acetylene-based diols; ester-type surfactants such as sorbitan fatty acid esters and glycerol volate fatty acid esters; polyoxyethylene alkylamines. Amino ether type surfactants such as; ether ester type surfactants such as polyoxyethylene sorbitan fatty acid ester, polyoxyethylene glycerol volate fatty acid ester, polyoxyethylene alkyl ester; fatty acid alkanolamide, polyoxyethylene fatty acid alkanolamide, etc. Alkanolamide type surfactant; oxyethylene adduct of acetylene diol; polyvinylpyrrolidone; polyacrylamide; polydimethylacrylamide; polyvinyl alcohol and the like. As the non-ionic surfactant, one type may be used alone, or two or more types may be used in combination.
本実施形態に係るＣＭＰ用研磨液は、界面活性剤以外に、所望とする特性に合わせてその他の成分を含有していてもよい。このような成分としては、後述するようなｐＨ調整剤、ｐＨの変動を抑えるためのｐＨ緩衝剤、アミノカルボン酸（第二の添加剤に該当する化合物を除く）、環状モノカルボン酸等が挙げられる。これらの成分の含有量は、研磨液の前記効果を過度に低下させない範囲とすることが好ましい。 The polishing liquid for CMP according to the present embodiment may contain other components in addition to the surfactant, depending on the desired properties. Examples of such a component include a pH adjuster as described later, a pH buffer for suppressing pH fluctuations, aminocarboxylic acid (excluding compounds corresponding to the second additive), cyclic monocarboxylic acid and the like. Be done. The content of these components is preferably in a range that does not excessively reduce the effect of the polishing liquid.
（ｐＨ）
本実施形態に係るＣＭＰ用研磨液のｐＨは、研磨液と被研磨膜（例えば、酸化ケイ素膜等の絶縁膜）との濡れ性が向上する観点、及び、砥粒の凝集を抑制し易くなる傾向がある観点から、８．０以下が好ましく、８．０未満がより好ましく、７．０以下が更に好ましく、６．０以下が特に好ましく、５．０以下が極めて好ましい。ｐＨが８．０以下であると、８．０を超える場合と比較して砥粒の凝集等を抑制し易く、前記添加剤を添加した効果が得られ易い。研磨液のｐＨは、１．５以上が好ましく、２．０以上がより好ましい。ｐＨが１．５以上であると、１．５未満の場合と比較して被研磨膜（例えば、酸化ケイ素膜等の絶縁膜）のゼータ電位の絶対値を大きな値とすることができる。本実施形態に係るＣＭＰ用研磨液のｐＨは、研磨液と被研磨膜（例えば、酸化ケイ素膜等の絶縁膜）との濡れ性が向上する観点から、２．０〜５．０であることが好ましい。なお、ｐＨは、液温２５℃におけるｐＨと定義する。
(PH)
The pH of the polishing liquid for CMP according to the present embodiment is from the viewpoint of improving the wettability between the polishing liquid and the film to be polished (for example, an insulating film such as a silicon oxide film), and makes it easy to suppress aggregation of abrasive grains. From the viewpoint of the tendency, 8.0 or less is preferable, less than 8.0 is more preferable, 7.0 or less is further preferable, 6.0 or less is particularly preferable, and 5.0 or less is extremely preferable. When the pH is 8.0 or less, it is easy to suppress the aggregation of abrasive grains and the like as compared with the case where it exceeds 8.0, and the effect of adding the additive is easy to be obtained. The pH of the polishing liquid is preferably 1.5 or higher, more preferably 2.0 or higher. When the pH is 1.5 or more, the absolute value of the zeta potential of the film to be polished (for example, an insulating film such as a silicon oxide film) can be made larger than that in the case of less than 1.5. The pH of the CMP polishing liquid according to the present embodiment is 2.0 to 5.0 from the viewpoint of improving the wettability between the polishing liquid and the film to be polished (for example, an insulating film such as a silicon oxide film). Is preferable. The pH is defined as the pH at a liquid temperature of 25 ° C.
本実施形態に係るＣＭＰ用研磨液のｐＨは、ｐＨメータ（例えば、ＨＯＲＩＢＡ製のＬＡＱＵＡ ａｃｔ）で測定することができる。例えば、フタル酸塩ｐＨ緩衝液（ｐＨ４．０１）と中性リン酸塩ｐＨ緩衝液（ｐＨ６．８６）とホウ酸塩ｐＨ緩衝液（ｐＨ９．１８）とを標準緩衝液として用いてｐＨメータを３点校正した後、ｐＨメータの電極を研磨液に入れて、２分以上経過して安定した後の値を測定する。このとき、標準緩衝液と研磨液の液温は共に２５℃とする。 The pH of the CMP polishing liquid according to this embodiment can be measured with a pH meter (for example, LAQUA act manufactured by HORIBA). For example, a pH meter using a phthalate pH buffer (pH 4.01), a neutral phosphate pH buffer (pH 6.86) and a borate pH buffer (pH 9.18) as standard buffers. After calibrating at three points, put the electrode of the pH meter in the polishing solution and measure the value after it stabilizes after 2 minutes or more. At this time, the liquid temperatures of the standard buffer solution and the polishing liquid are both set to 25 ° C.
ＣＭＰ用研磨液のｐＨを１．５〜８．０の範囲内に調整することで、次の２つの効果が得られると考えられる。
（１）添加剤として配合した化合物にプロトン又はヒドロキシアニオンが作用して、当該化合物の化学形態が変化し、基板表面の酸化ケイ素膜及び／又はストッパ膜（例えば窒化ケイ素膜）に対する濡れ性及び親和性が向上する。
（２）砥粒が酸化セリウムを含む場合、砥粒と酸化ケイ素膜との接触効率が向上し、更に高い研磨速度が達成される。これは、酸化セリウムのゼータ電位の符号が正であるのに対し、酸化ケイ素膜のゼータ電位の符号が負であり、両者の間に静電的引力が働くためであると考えられる。
It is considered that the following two effects can be obtained by adjusting the pH of the polishing liquid for CMP within the range of 1.5 to 8.0.
(1) A proton or hydroxy anion acts on a compound compounded as an additive to change the chemical form of the compound, resulting in wettability and affinity for a silicon oxide film and / or a stopper film (for example, a silicon nitride film) on the substrate surface. The sex is improved.
(2) When the abrasive grains contain cerium oxide, the contact efficiency between the abrasive grains and the silicon oxide film is improved, and a higher polishing rate is achieved. It is considered that this is because the sign of the zeta potential of cerium oxide is positive, while the sign of the zeta potential of the silicon oxide film is negative, and an electrostatic attractive force acts between the two.
ＣＭＰ用研磨液のｐＨは、添加剤として使用する化合物の種類によって変化し得る。そのため、ＣＭＰ用研磨液は、ｐＨを前記の範囲に調整するためにｐＨ調整剤を含有していてもよい。ｐＨ調整剤としては、特に制限はないが、硝酸、硫酸、塩酸、リン酸、ホウ酸等の酸；水酸化ナトリウム、アンモニア、水酸化カリウム、水酸化カルシウム等の塩基などが挙げられる。酢酸等の第三の添加剤を用いてｐＨを調整することもできる。なお、生産性が向上する観点から、ｐＨ調整剤を使用することなくＣＭＰ用研磨液を調製し、このようなＣＭＰ用研磨液をＣＭＰにそのまま適用してもよい。 The pH of the polishing solution for CMP can vary depending on the type of compound used as an additive. Therefore, the polishing liquid for CMP may contain a pH adjuster in order to adjust the pH to the above range. The pH adjusting agent is not particularly limited, and examples thereof include acids such as nitric acid, sulfuric acid, hydrochloric acid, phosphoric acid, and boric acid; and bases such as sodium hydroxide, ammonia, potassium hydroxide, and calcium hydroxide. The pH can also be adjusted with a third additive such as acetic acid. From the viewpoint of improving productivity, a CMP polishing liquid may be prepared without using a pH adjuster, and such a CMP polishing liquid may be applied to CMP as it is.
＜ＣＭＰ用研磨液の調製法及び使用法＞
ＣＭＰ用研磨液は、（Ａ）通常タイプ、（Ｂ）濃縮タイプ及び（Ｃ）２液タイプに分類でき、タイプによって調製法及び使用法が相違する。（Ａ）通常タイプは、研磨時に希釈等の前処理をせずにそのまま使用できる研磨液である。（Ｂ）濃縮タイプは、保管又は輸送の利便性を考慮し、（Ａ）通常タイプと比較して含有成分を濃縮した研磨液である。（Ｃ）２液タイプは、保管又は輸送に際して、一定の成分を含む液Ａと、他の成分を含む液Ｂとに分けた状態としておき、使用時に液Ａ及び液Ｂを混合して使用する研磨液である。
<Preparation and usage of polishing liquid for CMP>
Polishing solutions for CMP can be classified into (A) normal type, (B) concentrated type and (C) two-component type, and the preparation method and usage method differ depending on the type. (A) The normal type is a polishing liquid that can be used as it is without pretreatment such as dilution at the time of polishing. The (B) concentrated type is a polishing liquid in which the contained components are concentrated as compared with the (A) normal type in consideration of convenience of storage or transportation. (C) The two-component type is divided into a liquid A containing a certain component and a liquid B containing other components at the time of storage or transportation, and the liquid A and the liquid B are mixed and used at the time of use. It is a polishing liquid.
（Ａ）通常タイプは、砥粒、添加剤、及び、必要に応じてその他の成分を、主な分散媒である水に溶解又は分散させることによって得ることができる。例えば、砥粒の含有量０．５質量部、添加剤の含有量０．１質量部を有するＣＭＰ用研磨液１００質量部を１０００ｇ調製するには、ＣＭＰ用研磨液１０００ｇが砥粒５ｇ、添加剤１ｇを含有するように調整すればよい。 The (A) normal type can be obtained by dissolving or dispersing abrasive grains, additives and, if necessary, other components in water, which is the main dispersion medium. For example, in order to prepare 1000 g of 100 parts by mass of a CMP polishing liquid having an abrasive grain content of 0.5 parts by mass and an additive content of 0.1 parts by mass, 1000 g of the CMP polishing liquid is added with 5 g of abrasive grains. It may be adjusted so as to contain 1 g of the agent.
ＣＭＰ用研磨液は、例えば、攪拌機、ホモジナイザ、超音波分散機、湿式ボールミル等を使用して調製することができる。なお、砥粒の平均粒径が所望の範囲となるように、ＣＭＰ用研磨液の調製過程において砥粒の微粒子化処理を行ってもよい。砥粒の微粒子化処理は、沈降分級法又は高圧ホモジナイザを用いた方法によって実施できる。沈降分級法は、砥粒を含むスラリの粗大粒子を遠心分離機で強制的に沈降させる工程と、上澄み液のみを取り出す工程とを有する方法である。高圧ホモジナイザを用いた方法は、分散媒中の砥粒同士を高圧で衝突させる方法である。 The polishing liquid for CMP can be prepared by using, for example, a stirrer, a homogenizer, an ultrasonic disperser, a wet ball mill, or the like. In addition, the abrasive grains may be made into fine particles in the process of preparing the polishing liquid for CMP so that the average particle size of the abrasive grains is in a desired range. The fine particle treatment of the abrasive grains can be carried out by a sedimentation classification method or a method using a high-pressure homogenizer. The sedimentation classification method is a method including a step of forcibly sedimenting coarse particles of a slurry containing abrasive grains with a centrifuge and a step of taking out only the supernatant liquid. The method using a high-pressure homogenizer is a method in which abrasive grains in a dispersion medium collide with each other at high pressure.
（Ｂ）濃縮タイプは、使用直前に、含有成分の含有量が所望の含有量となるように水で希釈される。希釈後、（Ａ）通常タイプと同程度の液状特性（ｐＨ、砥粒の粒径等）及び研磨特性（例えば、酸化ケイ素膜の研磨速度、窒化ケイ素膜に対する酸化ケイ素膜の研磨選択比等）を再現できるまで、任意の時間にわたって攪拌又は砥粒の分散処理を行ってもよい。（Ｂ）濃縮タイプでは、濃縮の度合いに応じて容積が小さくなるため、保管及び輸送にかかるコストを減らすことができる。 (B) The concentrated type is diluted with water so that the content of the contained component becomes a desired content immediately before use. After dilution, (A) Liquid characteristics (pH, abrasive grain particle size, etc.) and polishing characteristics (for example, polishing rate of silicon oxide film, polishing selectivity of silicon oxide film to silicon nitride film, etc.) similar to those of the normal type) You may stir or disperse the abrasive grains for an arbitrary period of time until the above can be reproduced. (B) In the concentrated type, the volume becomes smaller according to the degree of concentration, so that the cost for storage and transportation can be reduced.
濃縮倍率は、１．５倍以上が好ましく、２倍以上がより好ましく、３倍以上が更に好ましく、５倍以上が特に好ましい。濃縮倍率が１．５倍以上であると、１．５倍未満の場合と比較して保管及び輸送に関するメリットを得ることができる。濃縮倍率は、４０倍以下が好ましく、２０倍以下がより好ましく、１５倍以下が更に好ましい。濃縮倍率が４０倍以下であると、４０倍を超える場合と比較して砥粒の凝集を抑制し易い。 The concentration ratio is preferably 1.5 times or more, more preferably 2 times or more, further preferably 3 times or more, and particularly preferably 5 times or more. When the concentration ratio is 1.5 times or more, advantages in storage and transportation can be obtained as compared with the case where the concentration ratio is less than 1.5 times. The concentration ratio is preferably 40 times or less, more preferably 20 times or less, still more preferably 15 times or less. When the concentration ratio is 40 times or less, it is easier to suppress the aggregation of abrasive grains as compared with the case where it exceeds 40 times.
（Ｂ）濃縮タイプの使用に際して注意すべき点は、水による希釈の前後でｐＨが変化する点である。（Ａ）通常タイプと同じｐＨの研磨液を（Ｂ）濃縮タイプから調製するには、水との混合によるｐＨ上昇を考慮に入れ、濃縮タイプの研磨液のｐＨを予め低めに設定しておけばよい。例えば、二酸化炭素が溶解した水（ｐＨ：約５．６）を使用し、ｐＨ４．０の（Ｂ）濃縮タイプの研磨液を１０倍に希釈した場合、希釈後の研磨液のｐＨは４．３程度にまで上昇する。 (B) A point to be noted when using the concentrated type is that the pH changes before and after dilution with water. In order to prepare a polishing solution having the same pH as the (A) normal type from the (B) concentrated type, the pH of the concentrated type polishing solution should be set low in advance in consideration of the pH increase due to mixing with water. Just do it. For example, when water in which carbon dioxide is dissolved (pH: about 5.6) is used and the (B) concentrated type polishing liquid having a pH of 4.0 is diluted 10 times, the pH of the diluted polishing liquid is 4. It rises to about 3.
（Ｂ）濃縮タイプのｐＨは、水による希釈後において適したｐＨの研磨液を得る観点から、１．５〜７．０が好ましい。ｐＨの下限は、１．５以上が好ましく、２．０以上がより好ましい。ｐＨの上限は、砥粒の凝集を抑制する観点から、７．０以下が好ましく、６．０以下がより好ましく、５．０以下が更に好ましい。 The pH of the (B) concentrated type is preferably 1.5 to 7.0 from the viewpoint of obtaining a polishing solution having a suitable pH after dilution with water. The lower limit of pH is preferably 1.5 or more, more preferably 2.0 or more. The upper limit of pH is preferably 7.0 or less, more preferably 6.0 or less, still more preferably 5.0 or less, from the viewpoint of suppressing aggregation of abrasive grains.
（Ｃ）２液タイプは、（Ｂ）濃縮タイプと比較して砥粒の凝集等を回避できるという利点がある。液Ａ及び液Ｂがそれぞれ含有する成分は任意である。例えば、砥粒と、必要に応じて配合される界面活性剤等とを含むスラリを液Ａとして調製し、添加剤と、必要に応じて配合される他の成分とを含む溶液を液Ｂとして調製することができる。この場合、液Ａにおける砥粒の分散性を高めるため、任意の酸又はアルカリを液Ａに配合し、ｐＨを調整してもよい。 The (C) two-component type has an advantage that agglutination of abrasive grains can be avoided as compared with the (B) concentrated type. The components contained in each of the liquid A and the liquid B are arbitrary. For example, a slurry containing abrasive grains and a surfactant or the like to be blended as needed is prepared as a liquid A, and a solution containing an additive and other components to be blended as needed is used as a liquid B. Can be prepared. In this case, in order to improve the dispersibility of the abrasive grains in the liquid A, an arbitrary acid or alkali may be added to the liquid A to adjust the pH.
（Ｃ）２液タイプの研磨液は、各成分が混合された状態では、砥粒の凝集等によって研磨特性が比較的短時間で低下する場合に有用である。なお、保管及び輸送にかかるコスト削減の観点から、液Ａ及び液Ｂを少なくとも一方を濃縮タイプとしてもよい。この場合、研磨液を使用する際に、液Ａと液Ｂと水とを混合すればよい。液Ａ又は液Ｂの濃縮倍率及びｐＨは任意であり、最終的な混合物の液状特性及び研磨特性が（Ａ）通常タイプの研磨液と同程度であればよい。 (C) The two-component type polishing liquid is useful when the polishing characteristics deteriorate in a relatively short time due to aggregation of abrasive grains or the like in a state where each component is mixed. From the viewpoint of cost reduction in storage and transportation, at least one of the liquid A and the liquid B may be a concentrated type. In this case, when the polishing liquid is used, the liquid A, the liquid B, and water may be mixed. The concentration ratio and pH of the liquid A or the liquid B are arbitrary, and the liquid characteristics and polishing characteristics of the final mixture may be similar to those of the (A) normal type polishing liquid.
＜研磨方法＞
本実施形態に係る研磨方法は、本実施形態に係るＣＭＰ用研磨液を用いた研磨方法であり、例えば、各成分の含有量及びｐＨ等が調整された研磨液を使用し、表面に絶縁膜（例えば、酸化ケイ素膜等の無機絶縁膜）を有する基板をＣＭＰ技術によって平坦化するものである。本実施形態に係る研磨方法は、具体的には、表面に絶縁膜（例えば、酸化ケイ素膜等の無機絶縁膜）を有する基板を研磨する研磨方法であって、本実施形態に係るＣＭＰ用研磨液を前記絶縁膜と所定の研磨用の部材（研磨部材、研磨パッド等）との間に供給しながら、前記研磨部材によって前記絶縁膜の研磨を行う工程を備える。
<Polishing method>
The polishing method according to the present embodiment is a polishing method using the polishing liquid for CMP according to the present embodiment. For example, a polishing liquid in which the content and pH of each component are adjusted is used, and an insulating film is formed on the surface. A substrate having (for example, an inorganic insulating film such as a silicon oxide film) is flattened by CMP technology. Specifically, the polishing method according to the present embodiment is a polishing method for polishing a substrate having an insulating film (for example, an inorganic insulating film such as a silicon oxide film) on the surface, and is a polishing method for CMP according to the present embodiment. A step of polishing the insulating film by the polishing member while supplying the liquid between the insulating film and a predetermined polishing member (polishing member, polishing pad, etc.) is provided.
本実施形態に係る研磨方法は、以下のようなデバイスの製造過程において、表面に被研磨膜（例えば、酸化ケイ素膜等の絶縁膜）を有する基板を研磨することに適している。デバイスとしては、例えば、ダイオード、トランジスタ、化合物半導体、サーミスタ、バリスタ、サイリスタ等の個別半導体；ＤＲＡＭ（ダイナミック・ランダム・アクセス・メモリー）、ＳＲＡＭ（スタティック・ランダム・アクセス・メモリー）、ＥＰＲＯＭ（イレイザブル・プログラマブル・リード・オンリー・メモリー）、マスクＲＯＭ（マスク・リード・オンリー・メモリー）、ＥＥＰＲＯＭ（エレクトリカル・イレイザブル・プログラマブル・リード・オンリー・メモリー）、フラッシュメモリ等の記憶素子；マイクロプロセッサー、ＤＳＰ、ＡＳＩＣ等の理論回路素子；ＭＭＩＣ（モノリシック・マイクロウェーブ集積回路）に代表される化合物半導体等の集積回路素子；混成集積回路（ハイブリッドＩＣ）、発光ダイオード、電荷結合素子等の光電変換素子などが挙げられる。 The polishing method according to the present embodiment is suitable for polishing a substrate having a film to be polished (for example, an insulating film such as a silicon oxide film) on the surface in the following device manufacturing process. Examples of devices include individual semiconductors such as diodes, transistors, compound semiconductors, thermistas, varistor, and thyristors; DRAM (dynamic random access memory), SRAM (static random access memory), and EPROM (erasable programmable). Storage elements such as read-only memory), mask ROM (mask read-only memory), EEPROM (electrical eraseable programmable read-only memory), flash memory; microprocessors, DSPs, ASICs, etc. Theoretical circuit elements; integrated circuit elements such as compound semiconductors typified by MMICs (monolithic microwave integrated circuits); photoelectric conversion elements such as hybrid integrated circuits (hybrid ICs), light emitting diodes, and charge coupling elements.
本実施形態に係るＣＭＰ用研磨液は、高い研磨速度を達成する効果を有する。このような研磨液を用いた研磨方法は、従来のＣＭＰ用研磨液を用いた方法では高い研磨速度を達成することが困難であった基板に対しても適用できる。例えば、メモリセルを有する半導体基板のように、上から見たときに凹部又は凸部がＴ字形状又は格子形状に設けられた部分を有する基板の被研磨膜（例えば、酸化ケイ素膜等の絶縁膜）を研磨する場合であってもその効果を発揮できる。 The polishing liquid for CMP according to the present embodiment has an effect of achieving a high polishing rate. Such a polishing method using a polishing liquid can be applied to a substrate in which it is difficult to achieve a high polishing speed by a conventional method using a polishing liquid for CMP. For example, an insulating film (for example, a silicon oxide film or the like) of a substrate having a portion in which concave portions or convex portions are provided in a T-shape or a lattice shape when viewed from above, such as a semiconductor substrate having a memory cell. The effect can be exhibited even when the film) is polished.
なお、当該研磨方法を適用できる基板は、基板表面全体が酸化ケイ素膜によって形成されたものに限らず、基板表面に酸化ケイ素膜の他に窒化ケイ素膜、多結晶シリコン膜等を更に形成したものであってもよい。また、当該研磨方法は、所定の配線を有する配線板上に、酸化ケイ素膜、ガラス、窒化ケイ素等の無機絶縁膜、ポリシリコン膜、Ａｌ、Ｃｕ、Ｔｉ、ＴｉＮ、Ｗ、Ｔａ、ＴａＮ等を主として含有する膜が形成された基板に対しても適用できる。 The substrate to which the polishing method can be applied is not limited to a substrate in which the entire surface of the substrate is formed of a silicon oxide film, and a silicon nitride film, a polycrystalline silicon film, or the like is further formed on the surface of the substrate in addition to the silicon oxide film. It may be. Further, in the polishing method, an inorganic insulating film such as a silicon oxide film, glass or silicon nitride, a polysilicon film, Al, Cu, Ti, TiN, W, Ta, TaN or the like is formed on a wiring plate having a predetermined wiring. It can also be applied to a substrate on which a film mainly contained is formed.
基板表面に酸化ケイ素膜を形成する方法としては、低圧ＣＶＤ法、プラズマＣＶＤ法等が挙げられる。低圧ＣＶＤ法による酸化ケイ素膜形成では、Ｓｉ源としてモノシラン（ＳｉＨ４）、酸素源として酸素（Ｏ２）を用いることができる。このＳｉＨ４−Ｏ２系酸化反応を４００℃以下の低温で行うことによって酸化ケイ素膜が形成される。場合によっては、ＣＶＤ後に１０００℃又はそれ以下の温度での熱処理が実施される。 Examples of the method for forming the silicon oxide film on the surface of the substrate include a low-voltage CVD method and a plasma CVD method. In the formation of the silicon oxide film by the low-pressure CVD method, monosilane (SiH 4 ) can be used as the Si source and oxygen (O 2 ) can be used as the oxygen source. A silicon oxide film is formed by carrying out this SiH 4- O 2 system oxidation reaction at a low temperature of 400 ° C. or lower. In some cases, heat treatment is performed at a temperature of 1000 ° C. or lower after CVD.
プラズマＣＶＤ法は、通常の熱平衡下では高温を必要とする化学反応が低温でできる利点を有する。プラズマ発生法には、容量結合型と誘導結合型の２つが挙げられる。反応ガスとしては、例えば、Ｓｉ源としてＳｉＨ４、酸素源としてＮ２Ｏを用いたＳｉＨ４−Ｎ２Ｏ系ガスや、テトラエトキシシラン（ＴＥＯＳ）をＳｉ源に用いたＴＥＯＳ−Ｏ２系ガス（ＴＥＯＳ−プラズマＣＶＤ法）が挙げられる。基板温度は２５０〜４００℃及び反応圧力は６７〜４００Ｐａの範囲が好ましい。 The plasma CVD method has an advantage that a chemical reaction requiring a high temperature can be performed at a low temperature under normal thermal equilibrium. There are two plasma generation methods, a capacitive coupling type and an inductively coupled type. Examples of the reaction gas include a SiH 4- N 2 O gas using SiH 4 as a Si source and N 2 O as an oxygen source, and a TEOS-O 2 gas using tetraethoxysilane (TEOS) as a Si source. (TEOS-plasma CVD method) can be mentioned. The substrate temperature is preferably in the range of 250 to 400 ° C. and the reaction pressure is preferably in the range of 67 to 400 Pa.
高温リフローによる表面平坦化を図るために、酸化ケイ素膜にリン（Ｐ）をドープする場合、ＳｉＨ４−Ｏ２−ＰＨ３系反応ガスを用いることが好ましい。このように、研磨対象の酸化ケイ素膜は、リン、ホウ素等の元素がドープされたものであってもよい。 In order to surface planarization by high temperature reflow, when doped with phosphorus (P) in the silicon oxide film, it is preferable to use a SiH 4 -O 2 -PH 3 system reaction gas. As described above, the silicon oxide film to be polished may be doped with an element such as phosphorus or boron.
窒化ケイ素膜も酸化ケイ素膜と同様、低圧ＣＶＤ法、プラズマＣＶＤ法等により形成することができる。低圧ＣＶＤ法では、例えば、Ｓｉ源としてジクロルシラン（ＳｉＨ２Ｃｌ２）、窒素源としてアンモニア（ＮＨ３）を用いることができる。このＳｉＨ２Ｃｌ２−ＮＨ３系酸化反応を９００℃の高温で行うことによって窒化ケイ素膜が形成される。プラズマＣＶＤ法における反応ガスとしては、例えば、Ｓｉ源としてＳｉＨ４、窒素源としてＮＨ３を用いたＳｉＨ４−ＮＨ３系ガスが挙げられる。この場合、基板温度は３００〜４００℃が好ましい。 Like the silicon oxide film, the silicon nitride film can also be formed by a low-pressure CVD method, a plasma CVD method, or the like. In the low-pressure CVD method, for example, dichlorosilane (SiH 2 Cl 2 ) can be used as the Si source, and ammonia (NH 3 ) can be used as the nitrogen source. Silicon nitride film is formed by performing this SiH 2 Cl 2 -NH 3 based oxidation reaction at a high temperature of 900 ° C.. Examples of the reaction gas in the plasma CVD method include a SiH 4- NH 3 system gas using SiH 4 as a Si source and NH 3 as a nitrogen source. In this case, the substrate temperature is preferably 300 to 400 ° C.
図１を参照して、本実施形態に係る研磨方法においてＣＭＰによって基板（ウエハ）にＳＴＩ構造を形成するプロセスについて説明する。図１は、酸化ケイ素膜が研磨されてシャロー・トレンチ分離構造が形成される過程を示す模式断面図である。本実施形態に係る研磨方法は、高い研磨速度で酸化ケイ素膜３を研磨する第一の工程（荒削り工程）と、残りの酸化ケイ素膜３を任意の膜厚となるように比較的低い研磨速度で研磨する第二の工程（仕上げ工程）とを備える。
With reference to FIG. 1, a process of forming an STI structure on a substrate (wafer) by CMP in the polishing method according to the present embodiment will be described. FIG. 1 is a schematic cross-sectional view showing a process in which a silicon oxide film is polished to form a shallow trench separation structure. The polishing method according to the present embodiment includes a first step (roughing step) of polishing the
図１（ａ）は研磨前の基板を示す断面図である。図１（ｂ）は第一の工程後の基板を示す断面図である。図１（ｃ）は第二の工程後の基板を示す断面図である。これらの図に示すように、ＳＴＩ構造を形成する過程では、シリコン基板１上に成膜した酸化ケイ素膜３の段差Ｄを解消するため、部分的に突出した不要な箇所をＣＭＰによって優先的に除去する。なお、表面が平坦化した時点で適切に研磨を停止させるため、酸化ケイ素膜３の下には、研磨速度の遅い窒化ケイ素膜（ストッパ膜）２を予め形成しておくことが好ましい。第一の工程及び第二の工程を経ることによって酸化ケイ素膜３の段差（膜厚の標高差）Ｄが解消され、埋め込み部分５を有する素子分離構造が形成される。
FIG. 1A is a cross-sectional view showing a substrate before polishing. FIG. 1B is a cross-sectional view showing the substrate after the first step. FIG. 1C is a cross-sectional view showing the substrate after the second step. As shown in these figures, in the process of forming the STI structure, in order to eliminate the step D of the
酸化ケイ素膜３を研磨するには、酸化ケイ素膜３の表面と研磨パッドとが当接するように、研磨パッド上に基板（ウエハ）を配置し、研磨パッドによって酸化ケイ素膜３の表面を研磨する。より具体的には、研磨定盤の研磨パッドに酸化ケイ素膜３の被研磨面側を押し当て、被研磨面と研磨パッドとの間にＣＭＰ用研磨液を供給しながら、両者を相対的に動かすことによって研磨パッドによって酸化ケイ素膜３を研磨する。
To polish the
本実施形態に係るＣＭＰ用研磨液は、第一及び第二の工程のいずれにも適用できるが、高い研磨速度を達成し得る点で第一の工程において使用することが特に好ましい。なお、ここでは、研磨工程を２段階に分けて実施する場合を例示したが、図１（ａ）に示す状態から図１（ｃ）に示す状態まで一段階で研磨処理することも可能である。 The CMP polishing liquid according to the present embodiment can be applied to both the first and second steps, but it is particularly preferable to use it in the first step because a high polishing rate can be achieved. Although the case where the polishing process is carried out in two stages is illustrated here, it is also possible to perform the polishing process in one stage from the state shown in FIG. 1 (a) to the state shown in FIG. 1 (c). ..
研磨装置としては、例えば、基板を保持するホルダーと、研磨パッドが貼り付けられる研磨定盤と、研磨パッド上に研磨液を供給する手段とを備える装置が好適である。研磨装置としては、株式会社荏原製作所製の研磨装置（型番：ＥＰＯ−１１１、ＥＰＯ−２２２、ＦＲＥＸ２００、ＦＲＥＸ３００）、アプライドマテリアル（ＡＭＡＴ）製の研磨装置（商品名：Ｍｉｒｒａ３４００、Ｒｅｆｌｅｘｉｏｎ研磨機）等が挙げられる。研磨パッドとしては、特に制限はなく、例えば、一般的な不織布、発泡ポリウレタン、多孔質フッ素樹脂等を使用することができる。また、研磨パッドは、研磨液が溜まるような溝加工が施されたものが好ましい。 As the polishing apparatus, for example, an apparatus provided with a holder for holding a substrate, a polishing surface plate to which a polishing pad is attached, and a means for supplying a polishing liquid on the polishing pad are suitable. As the polishing device, a polishing device manufactured by Ebara Corporation (model number: EPO-111, EPO-222, FREX200, FREX300), a polishing device manufactured by Applied Material (AMAT) (trade name: Mira3400, Reflection polishing machine), etc. Can be mentioned. The polishing pad is not particularly limited, and for example, a general non-woven fabric, polyurethane foam, porous fluororesin, or the like can be used. Further, the polishing pad is preferably grooved so that the polishing liquid can be collected.
研磨条件としては、特に制限はないが、基板が飛び出さないようにする観点から、研磨定盤の回転速度は２００ｍｉｎ−１以下が好ましく、基板にかける圧力（加工荷重）は、被研磨面の傷を抑制する観点から、１００ｋＰａ以下が好ましい。研磨している間、ポンプ等によって研磨パッドに研磨液を連続的に供給することが好ましい。この供給量に制限はないが、研磨パッドの表面が常に研磨液で覆われていることが好ましい。 The polishing conditions are not particularly limited, but from the viewpoint of preventing the substrate from popping out, the rotation speed of the polishing surface plate is preferably 200 min -1 or less, and the pressure (machining load) applied to the substrate is the surface to be polished. From the viewpoint of suppressing scratches, 100 kPa or less is preferable. During polishing, it is preferable to continuously supply the polishing liquid to the polishing pad by a pump or the like. There is no limit to the amount of this supply, but it is preferable that the surface of the polishing pad is always covered with the polishing liquid.
研磨終了後、流水中で基板を充分に洗浄し、更に、基板上に付着した水滴をスピンドライヤ等により払い落としてから乾燥させることが好ましい。 After the polishing is completed, it is preferable that the substrate is thoroughly washed in running water, and the water droplets adhering to the substrate are wiped off with a spin dryer or the like and then dried.
このように研磨することによって、表面の凹凸を解消し、基板全面にわたって平滑な面を得ることができる。膜の形成及びこれを研磨する工程を所定の回数繰り返すことによって、所望の層数を有する基板を製造することができる。 By polishing in this way, the unevenness of the surface can be eliminated and a smooth surface can be obtained over the entire surface of the substrate. By repeating the steps of forming the film and polishing the film a predetermined number of times, a substrate having a desired number of layers can be produced.
このようにして得られた基板は、種々の電子部品及び機械部品として使用することができる。具体例としては、半導体素子；フォトマスク、レンズ、プリズム等の光学ガラス；ＩＴＯ等の無機導電膜；ガラス及び結晶質材料で構成される光集積回路・光スイッチング素子・光導波路；光ファイバーの端面、シンチレータ等の光学用単結晶；固体レーザ単結晶；青色レーザＬＥＤ用サファイヤ基板；ＳｉＣ、ＧａＰ、ＧａＡｓ等の半導体単結晶；磁気ディスク用ガラス基板；磁気ヘッドなどが挙げられる。 The substrate thus obtained can be used as various electronic parts and mechanical parts. Specific examples include semiconductor devices; optical glass such as photomasks, lenses, and prisms; inorganic conductive films such as ITO; optical integrated circuits, optical switching elements, and optical waveguides composed of glass and crystalline materials; end faces of optical fibers, Optical single crystals such as scintillators; solid laser single crystals; sapphire substrates for blue laser LEDs; semiconductor single crystals such as SiC, GaP, and GaAs; glass substrates for magnetic disks; magnetic heads and the like.
以下、本発明を実施例により更に詳細に説明するが、本発明はこれらの実施例に限定されるものではない。 Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.
（砥粒の作製）
炭酸セリウム水和物４０ｋｇをアルミナ製容器に入れ、８３０℃で２時間、空気中で焼成して黄白色の粉末を２０ｋｇ得た。この粉末についてＸ線回折法で相同定を行い、当該粉末が多結晶体の酸化セリウムを含むことを確認した。焼成によって得られた粉末の粒径をＳＥＭで観察したところ、２０〜１００μｍであった。次いで、ジェットミルを用いて酸化セリウム粉末２０ｋｇを乾式粉砕した。粉砕後の酸化セリウム粉末をＳＥＭで観察したところ、結晶粒界を有する多結晶酸化セリウム粒子が含まれていることが確認された。また、酸化セリウム粉末の比表面積は９．４ｍ２／ｇであった。比表面積の測定はＢＥＴ法によって実施した。
(Making abrasive grains)
40 kg of cerium carbonate hydrate was placed in an alumina container and calcined in air at 830 ° C. for 2 hours to obtain 20 kg of a yellowish white powder. The powder was subjected to phase identification by X-ray diffraction, and it was confirmed that the powder contained polycrystalline cerium oxide. When the particle size of the powder obtained by firing was observed by SEM, it was 20 to 100 μm. Then, 20 kg of cerium oxide powder was dry-pulverized using a jet mill. When the cerium oxide powder after pulverization was observed by SEM, it was confirmed that polycrystalline cerium oxide particles having grain boundaries were contained. The specific surface area of the cerium oxide powder was 9.4 m 2 / g. The specific surface area was measured by the BET method.
（ＣＭＰ用研磨液の作製）
前記で得られた酸化セリウム粉末１５ｋｇ及び脱イオン水８４．７ｋｇを容器内に入れて混合した。更に、１Ｎの酢酸水溶液０．３ｋｇを添加して１０分間攪拌し、酸化セリウム混合液を得た。得られた酸化セリウム混合液を別の容器に３０分かけて送液した。その間、送液する配管内で、酸化セリウム混合液に対して超音波周波数４００ｋＨｚにて超音波照射を行った。
(Preparation of polishing liquid for CMP)
15 kg of the cerium oxide powder obtained above and 84.7 kg of deionized water were placed in a container and mixed. Further, 0.3 kg of a 1N aqueous acetic acid solution was added and stirred for 10 minutes to obtain a cerium oxide mixture. The obtained cerium oxide mixed solution was sent to another container over 30 minutes. During that time, the cerium oxide mixed solution was ultrasonically irradiated at an ultrasonic frequency of 400 kHz in the pipe to be fed.
５００ｍＬビーカー４個にそれぞれ５００ｇの酸化セリウム混合液を採取し、遠心分離を行った。遠心分離は、外周にかかる遠心力が５００Ｇになるような条件で２分間実施した。ビーカーの底に沈降した酸化セリウムを回収し、上澄みを分取した。液相の全質量基準で砥粒含有量を８．５質量％に調整した。その後、動的光散乱式粒度分布計（株式会社堀場製作所製、商品名：ＬＡ−９２０）を用いて砥粒の平均粒径を測定した結果、平均粒径は１５０ｎｍであった。 500 g of the cerium oxide mixed solution was collected in each of four 500 mL beakers and centrifuged. Centrifugation was carried out for 2 minutes under the condition that the centrifugal force applied to the outer circumference was 500 G. The cerium oxide that had settled on the bottom of the beaker was recovered, and the supernatant was separated. The abrasive grain content was adjusted to 8.5% by mass based on the total mass of the liquid phase. Then, as a result of measuring the average particle size of the abrasive grains using a dynamic light scattering type particle size distribution meter (manufactured by HORIBA, Ltd., trade name: LA-920), the average particle size was 150 nm.
前記で得られた砥粒及び各種第一の添加剤を、脱イオン水中にそれぞれ表１及び２の量で含有するスラリを得た。これを５分間以上攪拌し、各実施例及び比較例に係る研磨液を得た。各成分の含有量は研磨液全質量基準の含有量である。 A slurry containing the abrasive grains obtained above and various first additives in the amounts shown in Tables 1 and 2 in the deionized water was obtained. This was stirred for 5 minutes or more to obtain polishing liquids according to each Example and Comparative Example. The content of each component is based on the total mass of the polishing liquid.
動的光散乱式粒度分布計（株式会社堀場製作所製、商品名：ＬＡ−９２０）を用いて、研磨液における砥粒の平均粒径を測定したところ、いずれも平均粒径は１５０ｎｍであった。 When the average particle size of the abrasive grains in the polishing liquid was measured using a dynamic light scattering type particle size distribution meter (manufactured by HORIBA, Ltd., trade name: LA-920), the average particle size was 150 nm in each case. ..
研磨液のｐＨを以下の条件により測定した。
測定温度：２５℃
測定装置：ＨＯＲＩＢＡ製、型番ＬＡＱＵＡ ａｃｔ
測定方法：標準緩衝液（フタル酸塩ｐＨ緩衝液、ｐＨ：４．０１（２５℃）；中性リン酸塩ｐＨ緩衝液、ｐＨ：６．８６（２５℃）；ホウ酸塩ｐＨ緩衝液、ｐＨ：９．１８）を用いて３点校正した後、電極を研磨液に入れて、３分以上経過して安定した後のｐＨを前記測定装置により測定した。
The pH of the polishing liquid was measured under the following conditions.
Measurement temperature: 25 ° C
Measuring device: HORIBA, model number LAQUA act
Measuring method: standard buffer (phthalate pH buffer, pH: 4.01 (25 ° C); neutral phosphate pH buffer, pH: 6.86 (25 ° C); borate pH buffer, After calibrating at three points using pH: 9.18), the electrode was placed in a polishing solution, and after a lapse of 3 minutes or more and stabilized, the pH was measured by the measuring device.
（研磨特性評価）
［ウエハの準備］
前記のようにして調製した各ＣＭＰ用研磨液を使用し、表面に酸化ケイ素膜を有するブランケットウエハを研磨して研磨速度（ブランケットウエハ研磨速度）を求めた。ブランケットウエハは、シリコン基板上に配置された膜厚２０００ｎｍの酸化ケイ素膜を有するウエハを１．５ｃｍ角に切断したものである。
(Evaluation of polishing characteristics)
[Wafer preparation]
Using each CMP polishing liquid prepared as described above, a blanket wafer having a silicon oxide film on the surface was polished to determine the polishing rate (blanket wafer polishing rate). The blanket wafer is a wafer having a silicon oxide film having a film thickness of 2000 nm arranged on a silicon substrate and cut into 1.5 cm squares.
また、凹凸のある酸化ケイ素膜を被研磨膜として有するパターンウエハを準備した。このパターンウエハは、シリコン基板上の一部にストッパ膜として窒化ケイ素膜を形成した後、窒化ケイ素膜の無い部分のシリコン基板を３５０ｎｍエッチングして凹部を形成し、次いで、プラズマＣＶＤ法で２０００ｎｍの酸化ケイ素膜をストッパ膜上及び凹部内に成膜して得られたものである。パターンウエハは、Ｌｉｎｅ／Ｓｐａｃｅ＝３０００／３００μｍのパターンを有している。 In addition, a pattern wafer having an uneven silicon oxide film as a film to be polished was prepared. In this pattern wafer, a silicon nitride film is formed as a stopper film on a part of the silicon substrate, and then the silicon substrate in the portion without the silicon nitride film is etched by 350 nm to form a recess, and then a recess is formed by a plasma CVD method at 2000 nm. It is obtained by forming a silicon oxide film on the stopper film and in the recess. The pattern wafer has a pattern of Line / Space = 3000/300 μm.
［ウエハの研磨］
研磨装置（エンギス小型研磨機）を使用し、前記ブランケットウエハ及びパターンウエハを研磨した。また、直径２００ｍｍの研磨定盤に多孔質ウレタン樹脂製の研磨パッド（ｋ−ｇｒｏｏｖｅ溝、ロデール社製、型番：ＩＣ−１０１０）を貼り付けた。
[Wafer polishing]
The blanket wafer and the pattern wafer were polished using a polishing device (Engis small polishing machine). Further, a polishing pad (k-groove groove, manufactured by Roder, model number: IC-1010) made of a porous urethane resin was attached to a polishing surface plate having a diameter of 200 mm.
前記ウエハの酸化ケイ素膜形成面を下に向けてホルダーを研磨パッド上に載せた。ウエハ押付け圧力は、４０ｋＰａに設定した。 The holder was placed on the polishing pad with the silicon oxide film forming surface of the wafer facing down. The wafer pressing pressure was set to 40 kPa.
そして、前記のようにして調製した各ＣＭＰ用研磨液を、研磨定盤に貼り付けた研磨パッド上に４０ｍＬ／ｍｉｎの流量で滴下しながら、研磨定盤を回転数１８０ｍｉｎ−１、で回転させて、酸化ケイ素膜を研磨した。その後、研磨後のウエハを純水でよく洗浄した後、乾燥させた。 Then, while dropping each CMP polishing liquid prepared as described above onto the polishing pad attached to the polishing surface plate at a flow rate of 40 mL / min, the polishing surface plate is rotated at a rotation speed of 180 min -1 . The silicon oxide film was polished. Then, the polished wafer was thoroughly washed with pure water and then dried.
［研磨速度の評価］
光干渉式膜厚装置（Ｎａｎｏｍｅｔｒｉｃｓ製、商品名：Ｎａｎｏｓｐｅｃ）を用いてブランケットウエハ、パターンウエハの凸部、それぞれにおける研磨前後の酸化ケイ素膜の膜厚変化量を測定した。各ウエハの初期の６０秒間を研磨した際の膜厚変化量を研磨速度とした。
[Evaluation of polishing speed]
Using an optical interferometry film thickness device (manufactured by Nanometrics, trade name: Nanospec), the amount of change in film thickness of the silicon oxide film before and after polishing was measured at the convex portion of the blanket wafer and the pattern wafer. The amount of change in film thickness when polishing each wafer for the initial 60 seconds was defined as the polishing rate.
表１及び表２の結果から、第一の添加剤として４−ピロン系化合物又は４―ピリドン系化合物を使用した実施例３〜５、参考例１，２，６，７に係る研磨液は、比較例１に係る研磨液と比較し、高い研磨速度を達成することができることが示された。
From the results of Tables 1 and 2, the polishing liquids according to Examples 3 to 5 and Reference Examples 1 , 2, 6 and 7 using a 4-pyrone compound or a 4-pyridone compound as the first additive were found. It was shown that a higher polishing rate can be achieved as compared with the polishing solution according to Comparative Example 1.
本発明者等は発明を実施する最良の形態を明細書に記述している。前記の説明を同業者が読んだ場合、これらに似た好ましい変形形態が明らかになる場合もある。本発明者等は、本発明の異なる形態の実施、及び、本発明の根幹を適用した類似形態の発明の実施についても充分意識している。また、本発明にはその原理として、特許請求の範囲中に列挙した内容の全ての変形形態、更に、様々な前記要素の任意の組み合わせが利用できる。その全てのあり得る任意の組み合わせは、本明細書中において特別な限定がない限り、あるいは、文脈によりはっきりと否定されない限り、本発明に含まれる。 The inventors of the present invention describe in the specification the best mode for carrying out the invention. When the above description is read by those in the same industry, preferred variants similar to these may become apparent. The present inventors are also fully aware of the implementation of different embodiments of the present invention and the implementation of similar embodiments to which the basis of the present invention is applied. Further, in the present invention, as a principle, all modified forms of the contents listed in the claims, and any combination of various above-mentioned elements can be used. All possible combinations thereof are included in the present invention unless otherwise specified herein or expressly denied by the context.
本発明によれば、凹凸を有する、又は凹凸のない被研磨膜（例えば、酸化ケイ素膜等の絶縁膜）を研磨した場合において高い研磨速度を達成可能なＣＭＰ用研磨液、及び、これを用いた研磨方法を提供することができる。 According to the present invention, a CMP polishing liquid capable of achieving a high polishing rate when a film to be polished (for example, an insulating film such as a silicon oxide film) having or without unevenness is polished, and a polishing solution for CMP, which can be used. It is possible to provide a polishing method that has been used.
１…シリコン基板、２…窒化ケイ素膜（ストッパ膜）３…酸化ケイ素膜、５…埋め込み部分、Ｄ…酸化ケイ素膜の段差（膜厚の標高差）。 1 ... Silicon substrate, 2 ... Silicon nitride film (stopper film) 3 ... Silicon oxide film, 5 ... Embedded portion, D ... Step of silicon oxide film (elevation difference in film thickness).
Claims (12)
前記砥粒が酸化セリウムを含み、
前記第一の添加剤がマルトールプロピオナート（３―ヒドロキシ―２―メチル―４―ピロンプロピオナート）であり、
前記第二の添加剤が、酢酸、プロピオン酸、酪酸、イソ酪酸、吉草酸、イソ吉草酸、ピバル酸、ヒドロアンゲリカ酸、カプロン酸、２−メチルペンタン酸、４−メチルペンタン酸、２，３−ジメチルブタン酸、２−エチルブタン酸、２，２−ジメチルブタン酸及び３，３−ジメチルブタン酸からなる群より選ばれる少なくとも１種の飽和モノカルボン酸を含み、
ｐＨが２．０〜５．０である、
ＣＭＰ用研磨液。 Containing abrasive grains, a first additive, a second additive, and water,
The abrasive grains contain cerium oxide and
Is said first additive Gama Le Thor propionate (3-hydroxy-2-methyl-4-pyrone propionate),
The second additive is acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, isovaleric acid, pivalic acid, hydroangelica acid, caproic acid, 2-methylpentanoic acid, 4-methylpentanoic acid, 2,3. Includes at least one saturated monocarboxylic acid selected from the group consisting of −dimethylbutanoic acid, 2-ethylbutanoic acid, 2,2-dimethylbutanoic acid and 3,3-dimethylbutanoic acid.
The pH is 2.0-5.0,
Polishing liquid for CMP.
請求項１〜９のいずれか一項に記載のＣＭＰ用研磨液を前記絶縁膜と研磨パッドとの間に供給しながら、前記研磨パッドによって前記絶縁膜の研磨を行う工程を備える、研磨方法。 A polishing method for polishing a substrate having an insulating film on its surface.
A polishing method comprising a step of polishing the insulating film with the polishing pad while supplying the polishing solution for CMP according to any one of claims 1 to 9 between the insulating film and the polishing pad.
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