Polishing liquid for barrier layer

1 . A polishing liquid for polishing a barrier layer of a semiconductor integrated circuit, the polishing liquid comprising colloidal silica covered at a portion of a surface thereof with aluminum, and an oxidizing agent, wherein the polishing liquid has a pH of from 2 to 7.

2 . The polishing liquid according to claim 1 , wherein the primary particle diameter of the colloidal silica is from 10 to 60 nm.

3 . The polishing liquid according to claim 1 , wherein the concentration of the colloidal silica is from 1 to 15 mass % based on the mass of the polishing liquid.

4 . The polishing liquid according to claim 1 , further comprising a quaternary alkyl ammonium compound.

5 . The polishing liquid according to claim 1 , further comprising an anionic surfactant.

6 . The polishing liquid according to claim 1 , further comprising an organic acid having a carboxyl group.

7 . The polishing liquid according to claim 6 , wherein the organic acid is a compound represented by the following formula (1):

R—COOH  (1)

wherein R represents a hydrogen atom, a carboxyl group, or a hydrocarbon group, and the hydrocarbon group may further be substituted with a hydroxyl group, a carboxyl group, or a hydrocarbon group.

8 . The polishing liquid according to claim 1 , further comprising a heteroaromatic ring compound that contains three or more nitrogen atoms in the molecule and has a condensed ring structure.

9 . The polishing liquid according to claim 8 , wherein the heteroaromatic ring compound is benzotriazole or a derivative thereof.

10 . The polishing liquid according to claim 8 , wherein the concentration of the heteroaromatic ring compound is 0.2 mass % or less based on the mass of the polishing liquid.