Preparation of damage-free surface on alpha-alumina

• US 4,011,099 A
• Filed: 11/07/1975
• Issued: 03/08/1977
• Est. Priority Date: 11/07/1975
• Status: Expired due to Term

• Current Assignee: Solutia Incorporated (Eastman Chemical Company)
• Original Assignee: Monsanto Company (Bayer AG)
• Inventors: Gutsche, Henry W.
• Primary Examiner(s): Powell, William A.
• Assistant Examiner(s): Massie, Jerome W.
• Application Number:
  US05/629,949
• Time in Patent Office: 487 Days
• Field of Search: 156/2, 156/6, 156/20, 134/7, 134/19, 134/26, 134/28, 51/307, 51/308, 51/309, 51/317, 51/319, 51/323, 106/3, 252/79.1, 252/79.2
• US Class Current: 134/7
• CPC Class Codes: C09G 1/02 containing abrasives or grinding agents abrasives as such C09K3/14; polishing of semi-conductors H01L
• CPC Class Codes: C09K 13/04 containing an inorganic acid

Abstract

A chemical polishing process for alpha-alumina utilizing a silica colloid polishing fluid which is both a reactant and a medium for the removal of the reaction product is disclosed.

Claims

1. A process for preparing an undamaged surface on alpha-alumina comprising polishing an alpha-alumina surface with a colloidal silica fluid.

2. A process as claimed in claim 1, wherein said fluid comprises colloidal silica in water.

3. A process as claimed in claim 2, wherein said fluid has a pH of about 7 to 8.

4. A process as claimed in claim 2, wherein said fluid further comprises hydrochloric acid.

5. A process as claimed in claim 2, wherein said colloidal silica has a particle size of 250 - 300 Angstroms.

6. A process for preparing an undamaged surface on alpha-alumina comprising the steps of:

a. shaping the alpha-alumina with a diamond-impregnated saw blade;

b. heating to about 1000°

C in oxygen until all traces of diamond are removed;

c. polishing with a colloidal silica fluid under pressure;

d. immersing the alpha-alumina in hydrofluoric acid;

followed by

e. rinsing in deionized water.

7. A process as claimed in claim 6, wherein said fluid comprises colloidal silica in water.

8. A process as claimed in claim 6, wherein said fluid has a pH of about 7 to 8.

9. A process as claimed in claim 6, wherein said fluid further comprises hydrochloric acid.

10. A process as claimed in claim 6, wherein said colloidal silica has a particle size of 250 - 300 Angstroms.