Chemical mechanical polishing composition and method for polishing tungsten

1. A method of chemical mechanical polishing a substrate, comprising:

providing a polishing machine;

providing a substrate, wherein the substrate comprises tungsten;

providing a chemical mechanical polishing composition, wherein the chemical mechanical polishing composition, comprises:

a metal oxide abrasive;

an oxidizer, wherein the oxidizer is selected from the group consisting of KIO 3 and KIO 4 − ;

a tungsten removal rate enhancing substance according to formula I

wherein R 1 , R 2 and R 3 are each independently selected from a C 1-4 alky group; optionally, a pH adjusting agent; and,

water;

wherein the chemical mechanical polishing composition has a pH of 1 to 5; wherein the chemical mechanical polishing composition exhibits a tungsten removal rate, W RR , of ≧2,000 Å/min; and, wherein the tungsten removal rate enhancing substance according to formula I imparts the chemical mechanical polishing composition with an enhanced tungsten removal rate, wherein the following expression is satisfied

W RR >W RR 0

wherein W RR is the tungsten removal rate in Å/min for the chemical mechanical polishing composition and W RR 0 is a tungsten removal rate in Å/min obtained under identical conditions except that the tungsten removal rate enhancing substance according to formula I is absent from the chemical mechanical polishing composition; and, wherein the chemical mechanical polishing composition exhibits a tungsten removal rate enhancement, ΔW RR , of ≧10% according to the following equation

Δ W RR =(( W RR −W RR 0 )/ W RR 0 )*100%;

providing a chemical mechanical polishing pad;

installing the chemical mechanical polishing pad and the substrate in the polishing machine;

creating dynamic contact between the chemical mechanical polishing pad and the substrate;

dispensing the chemical mechanical polishing composition in proximity to an interface between the chemical mechanical polishing pad and the substrate;

wherein the chemical mechanical polishing composition comes into contact with tungsten of the substrate; and, wherein some tungsten is removed from the substrate.

2. The method of claim 1 , wherein the following equation is satisfied for the chemical mechanical polishing composition provided:

(( W RR −W RR 0 )/ W RR 0 )*100≧15.

3. The method of claim 2 , wherein the following equation is satisfied for the chemical mechanical polishing composition provided:

(( W RR −W RR 0 )/ W RR 0 )*100≧20.

4. The method of claim 2 , wherein the following equation is satisfied for the chemical mechanical polishing composition provided:

(( W RR −W RR 0 )/ W RR 0 )*100≧25.

5. The method of claim 1 , wherein the chemical mechanical polishing composition provided exhibits a tungsten removal rate, W RR , of ≧2,500 Å/min.

6. The method of claim 5 , wherein the following equation is satisfied for the chemical mechanical polishing composition provided:

(( W RR −W RR 0 )/ W RR 0 )*100≧15.

7. The method of claim 1 , wherein the substrate provided further comprises silicon oxide.

8. The method of claim 7 , wherein the chemical mechanical polishing composition provided exhibits a tungsten to silicon oxide removal rate selectivity of ≧5:1.

9. A method of chemical mechanical polishing a substrate, comprising:

providing a polishing machine;

providing a substrate, wherein the substrate comprises tungsten;

providing a chemical mechanical polishing composition, wherein the chemical mechanical polishing composition, consists of:

0.1 to 5 wt % of a silica abrasive;

0.1 to 0.5 wt % of a KIO 3 oxidizer;

0.01 to <1 wt % of a tungsten removal rate enhancing substance according to formula I

wherein R 1 , R 2 and R 3 are each independently selected from a C 1-4 alky group; optionally, a pH adjusting agent; and,

water;

wherein the chemical mechanical polishing composition has a pH of 1 to 5; wherein the chemical mechanical polishing composition exhibits a tungsten removal rate, W RR , of ≧2,000 Å/min; and, wherein the tungsten removal rate enhancing substance according to formula I imparts the chemical mechanical polishing composition with an enhanced tungsten removal rate, wherein the following expression is satisfied

W RR >W RR 0

wherein W RR is the tungsten removal rate in Å/min for the chemical mechanical polishing composition and W RR 0 is a tungsten removal rate in Å/min obtained under identical conditions except that the tungsten removal rate enhancing substance according to formula I is absent from the chemical mechanical polishing composition; and, wherein the chemical mechanical polishing composition exhibits a tungsten removal rate enhancement, ΔW RR , of ≧10% according to the following equation

Δ W RR =(( W RR −W RR 0 )/W RR 0 )*100%;

providing a chemical mechanical polishing pad;

installing the chemical mechanical polishing pad and the substrate in the polishing machine;

creating dynamic contact between the chemical mechanical polishing pad and the substrate;

dispensing the chemical mechanical polishing composition in proximity to an interface between the chemical mechanical polishing pad and the substrate;

wherein the chemical mechanical polishing composition comes into contact with tungsten of the substrate; and, wherein some tungsten is removed from the substrate.

10. The method of claim 9 , wherein R 1 , R 2 and R 3 are each independently selected from a C 1-2 alky group.

11. The method of claim 10 , wherein the chemical mechanical polishing composition, consists of:

0.1 to 5 wt % of the silica abrasive;

0.1 to 0.5 wt % of the KIO 3 oxidizer;

0.01 to 0.8 wt % of a tungsten removal rate enhancing substance according to formula I;

optionally, a pH adjusting agent; and,

water.

12. The method of claim 9 , wherein the substance according to formula I is benzyltrimethylammonium hydroxide.

13. The method of claim 12 , wherein the chemical mechanical polishing composition, consists of:

0.1 to 5 wt % of the silica abrasive;

0.1 to 0.5 wt % of the KIO 3 oxidizer;

0.01 to 0.8 wt % of a tungsten removal rate enhancing substance according to formula I;

optionally, a pH adjusting agent; and,

water.

14. The method of claim 13 , wherein the following equation is satisfied for the chemical mechanical polishing composition provided:

(( W RR −W RR 0 )/ W RR 0 )*100≧20.

15. The method of claim 13 , wherein the following equation is satisfied for the chemical mechanical polishing composition provided:

(( W RR −W RR 0 )/ W RR 0 )*100≧25.