Kit for polishing sapphire surfaces

Patent metadata

Field	Value
Publication number	US-9446493-B2
Application number	US-201615014548-A
Country	US
Kind code	B2
Filing date	Feb 3, 2016
Priority date	Aug 24, 2012
Publication date	Sep 20, 2016
Grant date	Sep 20, 2016

Abstract

Kits for polishing sapphire surfaces are disclosed. The kits have compositions including colloidal silica and the colloidal silica has a broad particle size distribution. The kits also include a polishing pad. The polishing pad may include polyurethane impregnated with polyester and it may have a compressibility of about 1% to about 40% and a Shore D hardness of about 50 to about 60.

First claim

The invention claimed is:

1. A kit for polishing a sapphire surface, the kit comprising:
(a) a polishing composition comprising colloidal silica having a particle size distribution of about 5 nm to about 120 nm, wherein the ratio of the standard deviation of the particle size of the colloidal silica (σ), to the mean particle size of the colloidal silica (r), is at least about 0.3; and
(b) a polishing pad comprising polyurethane impregnated with polyester, having a compressibility about 1% to about 40% and a Shore D hardness of about 50 to about 60.

2. The kit of claim 1 , wherein the colloidal silica comprises about 1 wt % to about 50 wt % of the polishing composition.

3. The kit of claim 1 , wherein the ratio σ/r is from about 0.3 to about 0.9.

4. The kit of claim 1 , wherein the colloidal silica composition has a mean particle size of about 5 nm, 6 nm, 7 nm, 8 nm, 9 nm, 10 nm, 11 nm, 12 nm, 13 nm, 14 nm, 15 nm, 16 nm, 17 nm, 18 nm, 19 nm, 20 nm, 21 nm, 22 nm, 23 nm, 24 nm, 25 nm, 26 nm, 27 nm, 28 nm, 29 nm, 30 nm, 31 nm, 32 nm, 33 nm, 34 nm, 35 nm, 36 nm, 37 nm, 38 nm, 39 nm, 40 nm, 41 nm, 42 nm, 43 nm, 44 nm, 45 nm, 46 nm, 47 nm, 48 nm, 49 nm, or 50 nm and each size is 0.5%, 1.0%, 1.5%, 2.0%, 2.5%, 3.0%, 3.5%, 4.0%, 4.5%, 5.0%, 5.5%, 6.0%, 6.5%, 7.0%, 7.5%, 8.0%, 8.5%, 9.0%, 9.5%, 10.0%, 10.5%, 11.0%, 11.5%, 12.0%, 12.5%, 13.0%, 13.5%, 14.0%, 14.5%, 15.0%, 15.5%, 16.0%, 16.5%, 17.0%, 17.5%, 18.0%, 18.5%, 19.0%, 19.5%, 20.0%, 20.5%, 21.0%, 21.5%, 22.0%, 22.5%, 23.0%, 23.5%, 24.0%, 24.5%, or 25.0% of the total mass of the colloidal silica particles used in the polishing composition.

5. The kit of claim 1 , wherein the colloidal silica has a mean particle size of about 5 nm to about 50 nm.

6. The kit of claim 1 , wherein the polishing composition further comprises an additional component selected from the group consisting of an alkaline substance, inorganic polishing particles, a water-soluble alcohol, a chelating agent and a buffering agent.

7. The kit of claim 1 , wherein a pH of the polishing composition is about 6 to about 10.5.

8. The kit of claim 1 , wherein the colloidal silica is prepared by a process comprising:
(a) feeding a first component including preformed silica sol particles of predetermined minimum particle size to at least one agitated, heated reactor;
(b) adding a second component including silicic acid to said reactor, wherein the second component is fed to the reactor at a rate that is less than a new silica particle nucleation rate;
(c) adding a third component including an alkaline agent to the reactor; and
(d) wherein the minimum particle size of the resulting colloidal silica is controlled by the particle size of the first component, and wherein the particle size distribution is dependent on the ratio of the feed rate of the first component to the reactor to the feed rate of the second component to the reactor.

Assignees

• Ecolab Usa Inc

Inventors

• Long Kim Marie
• Kamrath Michael A
• Mccue Sean P

Classifications

• B24B7/228 Primary

  for grinding thin, brittle parts, e.g. semiconductors, wafers (grinding edges of thin, brittle parts B24B9/065) · CPC title

• B24B37/044 Primary

  characterised by the composition of the lapping agent · CPC title

• C09G1/02

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

• C09G1/04

  Aqueous dispersions (C09G1/02 takes precedence) · CPC title

• B24B37/24

  characterised by the composition or properties of the pad materials · CPC title