Chemical mechanical polishing aqueous dispersion and chemical mechanical polishing method for semiconductor device
A chemical mechanical polishing aqueous dispersion of the invention includes (A) a first water-soluble polymer having a weight average molecular weight of 500,000 to 2,000,000 and including a heterocyclic ring in its molecule, (B) a second water-soluble polymer or its salt having a weight average molecular weight of 1000 to 10,000 and including one group selected from a carboxyl group and a sulfonic group, (C) an oxidizing agent, and (D) abrasive grains, and has a pH of 7 to 12.
1. A chemical mechanical polishing aqueous dispersion comprising:
(A) a first water-soluble polymer having a weight average molecular weight of from 1,500,000 to 2,000,000, a molecule of the first water-soluble polymer comprising a heterocyclic ring;
(B) a second water-soluble polymer or a salt of the second water-soluble polymer having a weight average molecular weight of 1000 to 10,000 and comprising one group selected from a carboxyl group and a sulfonic group;
(C) an oxidizing agent; and
(D) abrasive grains,
the chemical mechanical polishing aqueous dispersion having a pH of 7 to 12.
2. The chemical mechanical polishing aqueous dispersion as defined in claim 1 ,
wherein a mass ratio (A)/(B) of the first water-soluble polymer (A) and the second water-soluble polymer (B) is 0.02 to 50.
3. The chemical mechanical polishing aqueous dispersion as defined in claim 1 ,
wherein a 5 mass % aqueous solution of the first water-soluble polymer (A) has a viscosity of 50 to 150 mPa·s.
4. The chemical mechanical polishing aqueous dispersion as defined in claim 1 ,
wherein a 5 mass % aqueous solution of the second water-soluble polymer (B) has a viscosity of 1 to 5 mPa·s.
5. The chemical mechanical polishing aqueous dispersion as defined in claim 1 ,
wherein the first water-soluble polymer (A) is a copolymer having at least one structural unit derived from a compound selected from vinylpyridine, vinylpyrrolidone, and vinylimidazole.
6. The chemical mechanical polishing aqueous dispersion as defined in claim 1 ,
wherein the second water-soluble polymer (B) is a copolymer having at least one structural unit derived from a compound selected from acrylic acid, methacrylic acid, itaconic acid, maleic acid, styrenesulfonic acid, allylsulfonic acid, vinylsulphonic acid, and salts of acrylic acid, methacrylic acid, itaconic acid, maleic acid, styrenesulfonic acid, allylsulfonic acid, and vinylsulphonic acid.
7. The chemical mechanical polishing aqueous dispersion as defined in claim 1 , further comprising (E) a complex-forming agent and (F) a surfactant.
8. A chemical mechanical polishing method for a semiconductor device, the method comprising:
polishing a copper or copper alloy layer on a semiconductor substrate by using the chemical mechanical polishing aqueous dispersion as defined in claim 1 .
9. The chemical mechanical polishing aqueous dispersion of claim 1 , wherein the first water-soluble polymer is a polyvinyl pyrrolidone, and the second water- soluble polymer is at least one of a polymethacrylic acid and a polyacrylic acid.
10. The chemical mechanical polishing aqueous dispersion of claim 1 , wherein the first water-soluble polymer is present in a concentration of from 0.15 to 0.01 mass %.
11. The chemical mechanical polishing aqueous dispersion of claim 10 , wherein the second water-soluble polymer has a weight average molecular weight of from 1,600 to 10,000 and is present in a concentration of from 0.01 to 0.80 mass %.
12. The chemical mechanical polishing aqueous dispersion of claim 1 , having a pH of from 8.2 to 10.5.
13. The chemical mechanical polishing aqueous dispersion of claim 1 , wherein the first water-soluble polymer has a viscosity of 60.5-86.4 MPa·s as a 5 mass % aqueous solution.
14. The chemical mechanical polishing aqueous dispersion of claim 1 , wherein the second water-soluble polymer has a viscosity of 1.6 to 2.0 MPa·s as a 5 mass % aqueous solution.