OXIDIZER FREE SLURRY FOR RUTHENIUM CMP
The invention provides a chemical-mechanical polishing composition comprising(a) an abrasive having a Vickers hardness of 16 GPa or more, and (b) a liquid carrier, wherein the polishing composition is substantially free of an oxidizing agent and wherein the polishing composition has a pH of about 0 to about 7. The invention further provides a method of polishing a substrate, especially a substrate comprising ruthenium, with the polishing composition.
1 . A chemical-mechanical polishing composition comprising:
(a) an abrasive having a Vickers hardness of 16 GPa or more, and
(b) a liquid carrier,
wherein the polishing composition is substantially free of an oxidizing agent and wherein the polishing composition has a pH of about 0 to about 8.
2 . The polishing composition of claim 1 , wherein the polishing composition has a pH of about 1 to about 6.
3 . The polishing composition of claim 2 , wherein the polishing composition has a pH of about 2 to about 5.
4 . The polishing composition of claim 1 , wherein the abrasive has a Vickers hardness of 40 GPa or more.
5 . The polishing composition of claim 4 , wherein the abrasive has a Vickers hardness of 50 GPa or more.
6 . The polishing composition of claim 1 , wherein the abrasive comprises diamond, cubic boron nitride, α-Al 2 O 3 , or a combination thereof.
7 . The polishing composition of claim 6 , wherein the abrasive comprises diamond.
8 . The polishing composition of claim 1 , wherein the abrasive is present in the polishing composition at a concentration of about 0.001 wt. % to about 1 wt. %.
9 . The polishing composition of claim 8 , wherein the abrasive is present in the polishing composition at a concentration of about 0.001 wt. % to about 0.1 wt. %.
10 . The polishing composition of claim 9 , wherein the abrasive is present in the polishing composition at a concentration of about 0.001 wt. % to about 0.05 wt. %.
11 . The polishing composition of claim 1 , wherein the abrasive has an average particle size of about 1 nm to about 1 micron.
12 . The polishing composition of claim 11 , wherein the abrasive has an average particle size of about 5 nm to about 500 nm.
13 . The polishing composition of claim 12 , wherein the abrasive has an average particle size of about 5 nm to about 200 nm.
14 . A method of chemically-mechanically polishing a substrate comprising:
(i) providing a substrate, wherein the substrate comprises ruthenium on a surface of the substrate;
(ii) providing a polishing pad;
(iii) providing a chemical-mechanical polishing composition comprising:
(a) an abrasive having a Vickers hardness of 16 GPa or more, and
(b) a liquid carrier,
wherein the polishing composition is substantially free of an oxidizing agent and
wherein the polishing composition has a pH of about 0 to about 7;
(iv) contacting the substrate with the polishing pad and the polishing composition; and
(v) moving the polishing pad and the polishing composition relative to the substrate to abrade at least a portion of the ruthenium on the surface of the substrate to polish the substrate.
15 . The method of claim 14 , wherein the ruthenium further comprises carbon, oxygen, nitrogen, or a combination thereof.
16 . The method of claim 14 , wherein the polishing composition has a pH of about 1 to about 6.
17 . The method of claim 14 , wherein the abrasive comprises diamond, cubic boron nitride, α-Al 2 O 3 , or a combination thereof.
18 . The method of claim 17 , wherein the abrasive comprises diamond.
19 . The method of claim 14 , wherein the abrasive is present in the polishing composition at a concentration of about 0.001 wt. % to about 1 wt. %.
20 . The method of claim 14 , wherein the abrasive has an average particle size of about 1 nm to about 1 micron.