Polishing composition and polishing method

Abstract

The polishing composition contains polyoxyethylene sorbitan mono-fatty acid ester, silicon dioxide, water soluble cellulose, an alkaline compound, and water. The content of polyoxyethylene sorbitan mono-fatty acid ester in the polishing composition is less than 0.0025% by mass. The polishing composition is appropriate for final polishing of silicon wafers.

Description

Claims

1. A polishing composition comprising: polyoxyethylene sorbitan mono-fatty acid ester;silicon dioxide;water soluble cellulose;an alkaline compound; andwater,wherein the content of polyoxyethylene sorbitan mono-fatty acid ester in the polishing composition is less than 0.0025% by mass.

2. The polishing composition according to claim 1, wherein the content of polyoxyethylene sorbitan mono-fatty acid ester in the polishing composition is no more than 0.0015% by mass.

3. The polishing composition according to claim 1, wherein the HLB value of the polyoxyethylene sorbitan mono-fatty acid ester is 8 to 18.

4. The polishing composition according to claim 3, wherein the HLB value of the polyoxyethylene sorbitan mono-fatty acid ester is 14 to 17.

5. The polishing composition according to claim 1, wherein the silicon dioxide is colloidal silica or fumed silica.

6. The polishing composition according to claim 1, wherein the content of silicon dioxide in the polishing composition is no more than 2.5% by mass.

7. The polishing composition according to claim 1, wherein the water soluble cellulose is hydroxyalkyl cellulose or carboxyalkyl cellulose having an alkyl group of which the carbon number is 1 to 4.

8. The polishing composition according to claim 7, wherein the water soluble cellulose is hydroxyethyl cellulose, hydroxypropyl cellulose or carboxymethyl cellulose.

9. The polishing composition according to claim 1, wherein the viscosity average molecular weight of the water soluble cellulose is 100,000 to 3,000,000.

10. The polishing composition according to claim 1, wherein the content of water soluble cellulose in the polishing composition is no more than 0.15% by mass.

11. The polishing composition according to claim 1, wherein the alkaline compound is at least one type selected from the group consisting of ammonium, ammonium salts, alkaline metal hydroxides, alkaline metal salts, and quaternary ammonium hydroxides.

12. The polishing composition according to claim 11, wherein the alkaline compound is at least one type selected from the group consisting of ammonium, potassium hydroxide, sodium hydroxide, tetramethylammonium hydroxide, and tetraethylammonium hydroxide.

13. The polishing composition according to claim 11, wherein the content of the alkaline compound in the polishing composition is no more than 0.5% by mass.

14. The polishing composition according to claim 1, wherein the polishing composition is used in final polishing of a silicon wafer.

15. A polishing composition comprising: polyoxyethylene sorbitan mono-fatty acid ester, the content of which in the polishing composition is no more than 0.0015% by mass;colloidal silica, the content of which in the polishing composition is no more than 2.5% by mass;hydroxyethyl cellulose, the content of which in the polishing composition is no more than 0.15% by mass;an alkaline compound selected from the group consisting of ammonium, potassium hydroxide, sodium hydroxide, tetramethylammonium hydroxide, and tetraethylammonium hydroxide, the content of which in the polishing composition is no more than 0.5% by mass; andwater.

16. A method for polishing a silicon wafer, comprising final polishing of a silicon wafer using a polishing composition which includes polyoxyethylene sorbitan mono-fatty acid ester, silicon dioxide, water soluble cellulose, an alkaline compound, and water, wherein the content of polyoxyethylene sorbitan mono-fatty acid ester in the polishing composition is less than 0.0025% by mass according to claim 1.