Polishing liquid and polishing method
An aspect of the present invention is a polishing liquid containing abrasive grains, a copolymer, and a liquid medium, in which the copolymer has a structure unit derived from at least one styrene compound selected from the group consisting of styrene and a styrene derivative and a structure unit derived from acrylic acid, a content of the copolymer is more than 0.01% by mass and 0.2% by mass or less based on the total amount of the polishing liquid, and a pH of the polishing liquid is more than 4.5.
1. A polishing liquid comprising abrasive grains, a copolymer, and a liquid medium, wherein
a zeta potential of the abrasive grains is negative,
the copolymer comprises a structure unit derived from at least one styrene compound selected from the group consisting of styrene and a styrene derivative and a structure unit derived from acrylic acid,
a content of the copolymer is more than 0.01% by mass and less than 0.1% by mass based on the total amount of the polishing liquid, and
a pH of the polishing liquid is more than 4.5.
2. The polishing liquid according to claim 1 , wherein the pH of the polishing liquid is 7.5 or less.
3. The polishing liquid according to claim 1 , further comprising a water-soluble polymer.
4. The polishing liquid according to claim 1 , wherein a ratio of the structure unit derived from the styrene compound in the copolymer is 10 mol % or more.
5. The polishing liquid according to claim 1 , wherein a ratio of the structure unit derived from the styrene compound in the copolymer is 50 mol % or less.
6. The polishing liquid according to claim 1 , wherein the copolymer comprises a structure unit derived from styrene.
7. The polishing liquid according to claim 6 , wherein the content of the copolymer is more than 0.01% by mass and less than 0.1% by mass.
8. The polishing liquid according to claim 1 , wherein the abrasive grains comprise at least one selected from the group consisting of ceria, silica, alumina, zirconia, and yttria.
9. The polishing liquid according to claim 1 , further comprising a hydrogen phosphate compound.
10. The polishing liquid according to claim 1 , wherein a ratio of at least one group selected from the group consisting of a sulfonic acid group and a sultanate group in the copolymer is less than 5 mol%.
11. The polishing liquid according to claim 1 , wherein a content of the copolymer is more than 6 parts by mass with respect to 100 parts by mass of the abrasive grains.
12. The polishing liquid according to claim 1 , wherein the polishing liquid is used for polishing a surface to be polished comprising silicon oxide.
13. The polishing liquid according to claim 1 , wherein a content of the abrasive grains is 1.0% by mass or less based on the total amount of the polishing liquid.
14. A polishing method comprising a step of polishing a surface to be polished by using the polishing liquid according to claim 1 .
15. The polishing method according to claim 14 , wherein the surface to be polished comprises silicon oxide.
16. A polishing method for a surface to be polished comprising an insulating material and silicon nitride, the polishing method comprising:
a step of selectively polishing the insulating material with respect to the silicon nitride by using the polishing liquid according to claim 1 .
17. The polishing method according to claim 16 , wherein the insulating material comprises silicon oxide.
18. A polishing liquid comprising abrasive grains, a copolymer, and a liquid medium, wherein
the copolymer comprises a structure unit derived from at least one styrene compound selected from the group consisting of styrene and a styrene derivative and a structure unit derived from acrylic acid,
a ratio of the structure unit derived from the styrene compound in the copolymer is 10 mol % or more,
a content of the copolymer is more than 0.01% by mass and less than 0.1% by mass based on the total amount of the polishing liquid, and
a pH of the polishing liquid is more than 4.5.
19. A polishing liquid comprising abrasive grains, a copolymer, and a liquid medium, wherein
the copolymer comprises a structure unit derived from at least one styrene compound selected from the group consisting of styrene and a styrene derivative and a structure unit derived from acrylic acid,
a ratio of the structure unit derived from the styrene compound in the copolymer is 50 mol % or less,
a content of the copolymer is more than 0.01% by mass and less than 0.1% by mass based on the total amount of the polishing liquid, and
a pH of the polishing liquid is more than 4.5.