Polishing liquid and chemical mechanical polishing method
A polishing liquid, which is used for chemical mechanical polishing, includes ceria particles having an average aspect ratio of 1.5 or more; and an anionic polymer or a cationic polymer, in which a pH of the polishing liquid is 3 to 8. In a case where the polishing liquid contains the anionic polymer, the polishing liquid further includes an inorganic acid or an organic acid including at least one group selected from the group consisting of a carboxylic acid group, a phosphoric acid group, a phosphonic acid group, and a sulfonic acid group.
1. A polishing liquid used for chemical mechanical polishing, the polishing liquid comprising:
ceria particles having an average aspect ratio of 1.5 or more; and
an anionic polymer or a cationic polymer,
wherein the pH of the polishing liquid is 3 to 8,
the ceria particles contain alkaline earth metal atoms in at least one region of a surface thereof,
the mass content ratio of cerium atoms to the alkaline earth metal atoms on surfaces of the ceria particles is 5 or more,
the cationic polymer includes a first cationic polymer adsorbed on the ceria particles and a second cationic polymer not adsorbed on the ceria particles,
the ratio of the mass of the first cationic polymer to the mass of the second cationic polymer is 0.0005 to 1.50,
the anionic polymer includes a first anionic polymer adsorbed on the ceria particles and a second anionic polymer not adsorbed on the ceria particles, and the ratio of the mass of the first anionic polymer to the mass of the second anionic polymer is 0.001 to 1.00, and
in a case where the polishing liquid contains the anionic polymer, the polishing liquid further comprises: an inorganic acid or an organic acid including at least one group selected from the group consisting of a carboxylic acid group, a phosphoric acid group, a phosphonic acid group, and a sulfonic acid group.
2. The polishing liquid according to claim 1 , wherein the average aspect ratio of the ceria particles is 1.5 to 10.
3. The polishing liquid according to claim 1 , wherein the content of alkaline earth metal atoms is 10 mass ppt to 10 mass ppb with respect to the total mass of the ceria particles.
4. The polishing liquid according to claim 1 , wherein the ceria particle contains an oxide containing the alkaline earth metal atom.
5. The polishing liquid according to claim 1 , wherein a median diameter D10 of the ceria particles is 10 nm or less.
6. The polishing liquid according to claim 1 , wherein a median diameter D50 of the ceria particles is 15 nm or less.
7. The polishing liquid according to claim 1 , wherein a median diameter D90 of the ceria particles is 20 nm or less.
8. The polishing liquid according to claim 1 , further comprising one or more selected from the group consisting of a nitrogen-containing heterocyclic ring compound and 4-pyrone.
9. The polishing liquid according to claim 1 , further comprising an anionic surfactant.
10. The polishing liquid according to claim 1 , wherein the average primary particle size of the ceria particles is 20 nm or less.
11. The polishing liquid according to claim 1 , further comprising hexametaphosphoric acid.
12. The polishing liquid according to claim 1 , wherein the polishing liquid contains the cationic polymer.
13. The polishing liquid according to claim 12 ,
Wherein the ratio of the mass of the first cationic polymer to the mass of the second ionic polymer is 0.001 to 1.00.
14. The polishing liquid according to claim 12 , wherein the cationic polymer has a side chain including a cationic group.
15. The polishing liquid according to claim 1 ,
wherein, in a case where the polishing liquid is used for polishing silicon nitride, silicon oxide, or polysilicon,
a ratio of a polishing speed for the silicon oxide to a polishing speed for the silicon nitride is 10 to 5,000.
16. The polishing liquid according to claim 15 , wherein the ratio of the polishing speed for the silicon oxide to the polishing speed for the polysilicon is 10 to 5,000.
17. The polishing liquid according to claim 1 ,
wherein, in a case where the polishing liquid is used for polishing silicon nitride, silicon oxide, or polysilicon,
a ratio of a polishing speed for the silicon nitride to a polishing speed for the silicon oxide is 0.25 to 4.0.
18. The polishing liquid according to claim 17 , wherein the ratio of the polishing speed for the silicon nitride to the polishing speed for the polysilicon is 0.25 to 500.
19. A chemical mechanical polishing method comprising bringing a polishing target surface of a polishing target object into contact with a polishing pad while supplying the polishing liquid according to claim 1 to the polishing pad attached to a polishing platen, relatively moving the polishing target object and the polishing pad to polish the polishing target surface, and obtaining a polished polishing target object.
20. The chemical mechanical polishing method according to claim 19 , wherein the polishing target object includes silicon nitride and silicon oxide.
21. The chemical mechanical polishing method according to claim 20 , wherein the polishing target object further includes polysilicon.
22. The chemical mechanical polishing method according to claim 1 , wherein at least one region of a surface of the ceria particles is coated with an alkaline earth metal salt of a polycarboxylic acid.
23. The chemical mechanical polishing method according to claim 22 , wherein the ceria particles are particles produced by a production method including the following Step A1 and Step A2 or includes the following Step A3,
Step A1:
dispersing a mixed liquid obtained by mixing a solvent and cerium raw materials at a stirring speed of 500 to 5,000 rpm, and thereby preparing a dispersion liquid,
Step A2:
further adding polycarboxylic acid and an alkaline earth metal salt to the dispersion liquid obtained in Step A1, and thereby obtaining a dispersion liquid containing cerium atoms, and particles in which at least one region of a surface is coated with an alkaline earth metal salt of a polycarboxylic acid,
Step A3:
dispersing a mixed solution containing a solvent, cerium raw materials, a polycarboxylic acid, and an alkaline earth metal salt at a stirring speed of 500 to 5,000 rpm, and thereby obtaining a dispersion liquid containing cerium atoms, and particles in which at least one region of a surface is coated with an alkaline earth metal salt of a polycarboxylic acid.
24. The chemical mechanical polishing method according to claim 1 , wherein the content of the cationic polymer or the anionic polymer is 0.01 to 10% by mass with respect to the total mass of the polishing liquid.
25. The chemical mechanical polishing method according to claim 1 ,
wherein the inorganic acid or the organic acid includes at least one acid selected from the group consisting of acetic acid, oxalic acid, malic acid, glycine, 2-pyridinecarboxylic acid, phosphoric acid, phosphonic acid, 1-hydroxyethane-1,1-diphosphonic acid, sulfuric acid, and p-toluenesulfonic acid.
26. The chemical mechanical polishing method according to claim 1 ,
wherein the inorganic acid or the organic acid includes at least one acid selected from the group consisting of acetic acid, oxalic acid, malic acid, glycine, 2-pyridinecarboxylic acid, phosphoric acid, 1-hydroxyethane-1,1-diphosphonic acid, and p-toluenesulfonic acid.
27. The chemical mechanical polishing method according to claim 1 ,
wherein the polishing liquid contains the anionic polymer,
the anionic polymer includes at least one selected from the group consisting of polyacrylic acid and salts thereof, and copolymers containing them; polymethacrylic acid and salts thereof, and copolymers containing them; polyamic acids and salts thereof, and copolymers containing them; polymaleic acid and salts thereof, and copolymers containing them; polyitaconic acid and salts thereof, and copolymers containing them; polyfumaric acid and salts thereof, and copolymers containing them; poly(p-styrenecarboxylic acid) and salts thereof, and copolymers containing them; and polyglyoxylic acid and salts thereof, and copolymers containing them.
28. The chemical mechanical polishing method according to claim 1 ,
wherein the polishing liquid contains the anionic polymer, and
the anionic polymer includes at least one selected from the group consisting of polyacrylic acid and salts thereof, and copolymers containing them; polymethacrylic acid and salts thereof, and copolymers containing them.
29. The polishing liquid according to claim 1 , further comprising at least one compound selected from the group consisting of histidine, imidazole, 4-imidazolecarboxylic acid, 5-methylbenzotriazole, 5-aminobenzotriazole, benzotriazole, 5,6-dimethylbenzotriazole, 3-amino-1,2,4-triazole, 1,2,4-triazole, 3,5-dimethylpyrazole, pyrazole, and 4-pyrone.
30. The polishing liquid according to claim 9 , wherein the anionic surfactant includes at least one selected from carboxylic acid salts, sulfonic acid salts such as alkylbenzene sulfonic acid, sulfuric acid ester salts, and phosphoric acid ester salts.
31. A polishing liquid used for chemical mechanical polishing, the polishing liquid comprising:
ceria particles having an average aspect ratio of 1.5 or more; and
a cationic polymer,
wherein the pH of the polishing liquid is 3 to 8,
the cationic polymer includes a first cationic polymer adsorbed on the ceria particles and a second cationic polymer not adsorbed on the ceria particles, and
the ratio of the mass of the first cationic polymer to the mass of the second cationic polymer is 0.0005 to 1.50.
32. The polishing liquid according to claim 31 , further comprising at least one compound selected from the group consisting of histidine, imidazole, 4-imidazolecarboxylic acid, 5-methylbenzotriazole, 5-aminobenzotriazole, benzotriazole, 5,6-dimethylbenzotriazole, 3-amino-1,2,4-triazole, 1,2,4-triazole, 3,5-dimethylpyrazole, pyrazole, and 4-pyrone.
33. The polishing liquid according to claim 31 , further comprising an anionic surfactant, and
wherein the anionic surfactant includes at least one selected from carboxylic acid salts, sulfonic acid salts such as alkylbenzene sulfonic acid, sulfuric acid ester salts, and phosphoric acid ester salts.