Polishing composition

1. A polishing composition, comprising silica particles as abrasives and a basic compound as polishing removal accelerator, wherein

a density of silanol groups of the silica particles is 1.5 to 6.0 pieces/nm 2 ,

an adsorption ratio parameter A of the polishing composition is 1.2 or less, the adsorption ratio parameter represents concentration dependency of an amount of adsorption of the basic compound to the silica particles as a ratio of high-concentration adsorption amount/low-concentration adsorption amount, and

the polishing composition has a pH of 8 to 12.

2. The polishing composition according to claim 1 , wherein the adsorption ratio parameter A is 1.1 or less.

3. The polishing composition according to claim 1 , wherein a density of silanol groups of the silica particles is 1.5 to 4.0 pieces/nm 2 .

4. The polishing composition according to claim 1 , wherein the basic compound includes one type or two types or more of compounds selected from the group consisting of the following general formula (A) and general formula (B):

in the general formula (A), X 1 denotes a hydrogen atom, an amino group, or a bond to C 1 atom, when X 1 denotes a bond to C 1 atom, H 1 atom is not present and X 2 denotes a hydrogen atom, an amino group, an aminoalkyl group or a bond to C 1 atom, when X 2 denotes a bond to C 1 atom, a C 1 —N 1 bond is a double bond and H 2 atom is not present, l denotes an integer from 1 to 6, m denotes an integer from 1 to 4, and n denotes an integer from 0 to 4, and

in the general formula (B), R 1 to R 4 are selected independently from the group consisting of an alkyl group having the number of carbon atom of 8 or less, a hydroxyalkyl group having the number of carbon atom of 8 or less and an optionally substituted aryl group, and X− is an anion.

5. The polishing composition according to claim 4 , comprising aminoalkylpiperazine as a compound represented by the general formula (A).

6. The polishing composition according to claim 1 , wherein the polishing composition does not include oxidant substantially.

7. The polishing composition according to claim 1 , wherein the silica particles comprise colloidal silica.

8. The polishing composition according to claim 1 , wherein the polishing composition is used for polishing of a silicon wafer.

9. The polishing composition according to claim 2 , wherein a density of silanol groups of the silica particles is 1.5 to 4.0 pieces/nm 2 .

10. The polishing composition according to claim 2 , wherein the basic compound includes one type or two types or more of compounds selected from the group consisting of the following general formula (A) and general formula (B):

in the general formula (A), X 1 denotes a hydrogen atom, an amino group, or a bond to C 1 atom, when X 1 denotes a bond to C 1 atom, H 1 atom is not present and X 2 denotes a hydrogen atom, an amino group, an aminoalkyl group or a bond to C 1 atom, when X 2 denotes a bond to C 1 atom, a C 1 —N 1 bond is a double bond and H 2 atom is not present, l denotes an integer from 1 to 6, m denotes an integer from 1 to 4, and n denotes an integer from 0 to 4, and

in the general formula (B), R 1 to R 4 are selected independently from the group consisting of an alkyl group having the number of carbon atom of 8 or less, a hydroxyalkyl group having the number of carbon atom of 8 or less and an optionally substituted aryl group, and X− is an anion.

11. The polishing composition according to claim 3 , wherein

the basic compound includes one type or two types or more of compounds selected from the group consisting of the following general formula (A) and general formula (B):

in the general formula (A), X 1 denotes a hydrogen atom, an amino group, or a bond to C 1 atom, when X 1 denotes a bond to C 1 atom, H 1 atom is not present and X 2 denotes a hydrogen atom, an amino group, an aminoalkyl group or a bond to C 1 atom, when X 2 denotes a bond to C 1 atom, a C 1 —N 1 bond is a double bond and H 2 atom is not present, l denotes an integer from 1 to 6, m denotes an integer from 1 to 4, and n denotes an integer from 0 to 4, and

in the general formula (B), R 1 to R 4 are selected independently from the group consisting of an alkyl group having the number of carbon atom of 8 or less, a hydroxyalkyl group having the number of carbon atom of 8 or less and an optionally substituted aryl group, and X− is an anion.

12. The polishing composition according to claim 2 , wherein the polishing composition does not include oxidant substantially.

13. The polishing composition according to claim 3 , wherein the polishing composition does not include oxidant substantially.

14. The polishing composition according to claim 4 , wherein the polishing composition does not include oxidant substantially.

15. The polishing composition according to claim 5 , wherein the polishing composition does not include oxidant substantially.

16. The polishing composition according to claim 1 , wherein 50% by weight or more of the basic compound included in the polishing composition is an organic basic compound.

17. The polishing composition according to claim 1 , wherein the amount of the polishing removal accelerator included in the polishing composition is 50g to 1000g per abrasives of 1kg.

18. The polishing composition according to claim 1 , wherein the polishing composition comprises chelating agent.

19. The polishing composition according to claim 1 , wherein the polishing composition comprises water-soluble polymer.

20. The polishing composition according to claim 1 , wherein the polishing composition comprises surfactant.