Compositions for polishing aluminum/copper and titanium in damascene structures

1. A chemical-mechanical polishing composition consisting essentially of:

(a) an abrasive consisting of alumina particles treated with an anionic polymer, wherein the anionic polymer is poly(2-acrylamido-2-methylpropane sulfonic acid) or polystyrenesulfonic acid,

(b) an α-hydroxycarboxylic acid,

(c) an oxidizing agent that oxidizes at least one metal,

(d) about 0.01 wt. % to about 0.2 wt. % polyacrylic acid,

(e) optionally, a calcium-containing compound,

(f) optionally, a biocide,

(g) optionally, a pH adjusting agent, and

(h) water,

wherein the polishing composition has a pH of about 2 to about 6.

2. The polishing composition of claim 1 , wherein the abrasive is about 0.1 wt. % to about 1 wt. % of the polishing composition.

3. The polishing composition of claim 1 , wherein the α-hydroxycarboxylic acid is lactic acid.

4. The polishing composition of claim 3 , wherein the lactic acid is about 0.5 wt. % to about 2 wt. % of the polishing composition.

5. The polishing composition of claim 1 , wherein the oxidizing agent is selected from the group consisting of ammonium persulfate, ferric nitrate, and combinations thereof.

6. The polishing composition of claim 1 , wherein the oxidizing agent is hydrogen peroxide.

7. The polishing composition of claim 1 , wherein the calcium-containing compound is about 0.001 wt. % to about 0.05 wt. % of the polishing composition.

8. The polishing composition of claim 1 , wherein the polishing composition has a pH of about 2 to about 4.