Polishing composition

Patent metadata

Field	Value
Publication number	US-10570322-B2
Application number	US-201916245030-A
Country	US
Kind code	B2
Filing date	Jan 10, 2019
Priority date	Jan 19, 2015
Publication date	Feb 25, 2020
Grant date	Feb 25, 2020

Abstract

Disclosed herein is a polishing composition comprising a pH of 6 or less, sulfonic acid-modified colloidal silica obtained by immobilizing sulfonic acid on surfaces of silica particles, and water, wherein the sulfonic acid-modified colloidal silica is derived from sulfonic acid-modified aqueous anionic silica sol produced by a production method comprising: a first reaction step of obtaining a reactant by heating raw colloidal silica having a number distribution ratio of 10% or less of microparticles having a particle diameter of 40% or less relative to a volume average particle diameter based on Heywood diameter (equivalent circle diameter) as determined by image analysis using a scanning electron microscope in the presence of a silane coupling agent having a functional group chemically convertible to a sulfonic acid group; and a second reaction step of converting the functional group to a sulfonic acid group by treating the reactant.

First claim

The invention claimed is:

1. A method of producing a sulfonic acid-modified aqueous anionic silica sol obtained by immobilizing sulfonic acid on surfaces of silica particles comprising:
a first reaction step comprising obtaining a reactant by heating raw colloidal silica having a number distribution ratio of 10% or less of microparticles having a particle diameter of 40% or less relative to a volume average particle diameter based on Heywood diameter (equivalent circle diameter) as determined by image analysis using a scanning electron microscope in the presence of a silane coupling agent having a functional group chemically convertible to a sulfonic acid group; and
a second reaction step comprising converting the functional group to a sulfonic acid group by treating the reactant,
wherein the method further comprises distilling off an organic solvent coexisting with colloidal silica under a condition of pH 7 or more so that a residual organic solvent concentration in colloidal silica having an organic solvent concentration of 1% by mass or more becomes less than 1% by mass to obtain the raw colloidal silica.

2. The method of claim 1 , wherein the functional group is a mercapto group.

3. The method of claim 2 , wherein the treatment is an oxidation treatment using hydrogen peroxide.

4. The method of claim 3 , wherein an addition amount of the hydrogen peroxide is 3 to 5 mol times relative to an addition amount of the silane coupling agent, and a residual hydrogen peroxide concentration in the obtained aqueous anionic silica sol is 500 ppm by mass or less.

5. A method of producing a polishing composition having a pH of 6 or less comprising mixing the sulfonic acid-modified silica sol of claim 1 and water.

6. The method of claim 5 , wherein the polishing composition is suitable for an application of polishing silicon nitride.

7. The method of claim 1 , wherein the total content of metal impurities in the sulfonic acid-modified aqueous anionic silica is 1 ppm by mass or less.

8. A method of producing a sulfonic acid-modified aqueous anionic silica sol obtained by immobilizing sulfonic acid on surfaces of silica particles comprising:
a first reaction step comprising obtaining a reactant by heating raw colloidal silica having a number distribution ratio of 10% or less of microparticles having a particle diameter of 40% or less relative to a volume average particle diameter based on Heywood diameter (equivalent circle diameter) as determined by image analysis using a scanning electron microscope in the presence of a silane coupling agent having a functional group chemically convertible to a sulfonic acid group; and
a second reaction step comprising converting the functional group to a sulfonic acid group by treating the reactant,
wherein the method further comprises lowering a viscosity of the raw colloidal silica by adding an alkaline solution or an organic solvent to the raw colloidal silica before the first reaction step.

9. The method of claim 8 , wherein the method further comprises distilling off an organic solvent coexisting with colloidal silica under a condition of pH 7 or more so that a residual organic solvent concentration in colloidal silica having an organic solvent concentration of 1% by mass or more becomes less than 1% by mass to obtain the raw colloidal silica.

10. The method of claim 8 , wherein the functional group is a mercapto group.

11. The method of claim 10 , wherein the treatment is an oxidation treatment using hydrogen peroxide.

12. The method of claim 11 , wherein an addition amount of the hydrogen peroxide is 3 to 5 mol times relative to an addition amount of the silane coupling agent, and a residual hydrogen peroxide concentration in the obtained aqueous anionic silica sol is 500 ppm by mass or less.

13. The method of claim 8 , wherein in the production method, the first reaction step is performed under a condition that a temperature condition of 90° C. or more is continued for 30 minutes or more.

14. A method of producing a polishing composition having a pH of 6 or less comprising mixing the sulfonic acid-modified silica sol of claim 8 and water.

15. The method of claim 14 , wherein the polishing composition is suitable for an application of polishing silicon nitride.

16. The method of claim 8 , wherein the total content of metal impurities in the sulfonic acid-modified aqueous anionic silica is 1 ppm by mass or less.

17. A method of producing a sulfonic acid-modified aqueous anionic silica sol obtained by immobilizing sulfonic acid on surfaces of silica particles comprising:
a first reaction step comprising obtaining a reactant by heating raw colloidal silica having a number distribution ratio of 10% or less of microparticles having a particle diameter of 40% or less relative to a volume average particle diameter based on Heywood diameter (equivalent circle diameter) as determined by image analysis using a scanning electron microscope in the presence of a silane coupling agent having a functional group chemically convertible to a sulfonic acid group; and
a second reaction step comprising converting the functional group to a sulfonic acid group by treating the reactant,
wherein in the production method, the first reaction step is performed under a condition that a temperature condition of 90° C. or more is continued for 30 minutes or more.

18. The method of claim 17 , wherein the method further comprises distilling off an organic solvent coexisting with colloidal silica under a condition of pH 7 or more so that a residual organic solvent concentration in colloidal silica having an organic solvent concentration of 1% by mass or more becomes less than 1% by mass to obtain the raw colloidal silica.

19. The method of claim 17 , wherein the functional group is a mercapto group.

20. The method of claim 19 , wherein the treatment is an oxidation treatment using hydrogen peroxide.

21. The method of claim 20 , wherein an addition amount of the hydrogen peroxide is 3 to 5 mol times relative to an addition amount of the silane coupling agent, and a residual hydrogen peroxide concentration in the obtained aqueous anionic silica sol is 500 ppm by mass or less.

22. A method of producing a polishing composition having a pH of 6 or less comprising mixing the sulfonic acid-modified silica sol of claim 17 and water.

23. The method of claim 22 , wherein the polishing composition is suitable for an application of polishing silicon nitride.

24. The method of claim 17 , wherein the total content of metal impurities in the sulfonic acid-modified aqueous anionic silica is 1 ppm by mass or less.

Assignees

• Fujimi Inc

Inventors

• Ashitaka Keiji
• Tsubota Shogo

Classifications

• H10P95/062

  involving a dielectric removal step · CPC title

• B24B37/044

  characterised by the composition of the lapping agent · CPC title

• C09G1/02 Primary

  containing abrasives or grinding agents {(abrasives as such C09K3/14; polishing of semi-conductors H10P52/40)} · CPC title

• C09K3/1463 Primary

  Aqueous liquid suspensions · CPC title

• C09K3/1436 Primary

  Composite particles, e.g. coated particles · CPC title