Polishing liquid
View Patent ↗According to an aspect of the invention, there is provided a polishing liquid for polishing a barrier metal material on an interlayer insulation material, the polishing liquid having a pH of from 2.0 to 6.0 and including an aqueous solution containing a compound represented by the following formula (1), and polishing particles containing silicon oxide and dispersed in the aqueous solution: R 1 —(CH 2 ) m —(CHR 2 ) n —COOH (1) wherein m+n≦4; R 1 represents a hydrogen atom, a methyl group, an ethyl group or a hydroxyl group; R 2 represents a methyl group, an ethyl group, a benzene ring or a hydroxyl group; and when a plurality of R 2 s are present in the formula (1), they are the same or different from one another.
1. A polishing method comprising polishing a barrier metal material on an interlayer insulation material, the polishing using a polishing liquid, wherein the polishing liquid has a pH of from 2.0 to 6.0 and comprises
an aqueous solution containing a compound represented by the following formula ( 1 ), the content of the compound in the polishing liquid being from 0.0005 to 3 mol/L,
polishing particles containing silicon oxide and dispersed in the aqueous solution, the content of the polishing particles in the polishing liquid being from 0.01 to 20% by mass, and
a heterocyclic compound selected from the group consisting of 1,2,3,4-tetrazole, 5-amino-1,2,3,4-tetrazole, 5-methyl-1,2,3,4-tetrazole, 1,2,3-triazole, 4-amino-1,2,3-triazole, 4,5-diamino-1,2,3-triazole, 1,2,4-triazole, 3-amino-1,2,4-triazole, 3,5-diamino-1,2,4-triazole and benzotriazole, the content of the heterocyclic compound in the polishing liquid being from 0.01 to 0.10% by mass:
R 1 —(CH 2 ) m —(CHR 2 ) n —COOH (1)
wherein 1≦m+n≦4; R 1 represents a hydrogen atom, a methyl group, an ethyl group or a hydroxyl group; R 2 represents a methyl group, an ethyl group, a benzene ring or a hydroxyl group; and when a plurality of R 2 s are present in the formula (1), they are the same or different from one another;
wherein the electric conductivity of the polishing liquid is from 0.2 to 8.0 mS/cm.
2. The polishing method according to claim 1 , wherein the compound represented by formula (1) is a compound selected from the group consisting of lactic acid, glycolic acid, acetic acid, propionic acid, butyric acid, methyl valeric acid, capronic acid and mandelic acid;
3. The polishing method according to claim 1 , wherein the polishing particles are colloidal silica or composite particles containing colloidal silica, and have a primary particle diameter, which is determined by converting the specific surface area of the particles into a true sphere particle model, of from 15 to 70 nm.
4. The polishing method according to claim 1 , wherein the barrier metal material contains at least one selected from the group consisting of tantalum, tantalum nitride, titanium, titanium nitride, tungsten, tungsten nitride, nickel, nickel nitride, ruthenium and compounds thereof.
5. The polishing method according to claim 1 , further containing an oxidizing agent.
6. The polishing method according to claim 5 , wherein the oxidizing agent contains at least one selected from the group consisting of hydrogen peroxide, peroxides, nitrate salts, iodate salts, periodate salts, hypochlorite salts, chlorite salts, chlorate salts, perchlorate salts, persulfate salts, bichromate salts, permanganate salts, aqueous ozone, silver (II) salts and iron (III) salts.
7. The polishing method according to claim 5 , wherein the content of the oxidizing agent is from 0.01 to 1 mol/L.
8. The polishing method according to claim 1 , wherein the polishing liquid has a pH of from 2.4 to 5.5.