US3922393A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for polishing silicon and germanium semiconductor materials
Assignee: EIDP Inc
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Filing: 1974-07-02
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Granted: 1975-11-25
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Expires: 1994-07-02
Abstract
Abstract There is provided a process for polishing monocrystalline semiconductor materials of silicon and germanium to a high degree of surface perfection comprising polishing the material with a modified colloidal silica sol having a pH between about 11 to 12.5 and composed of colloidal silica particles which are coated with chemically combined atoms of aluminum to give a surface coverage of about 1 to about 50 aluminum atoms on the surface per 100 silicon atoms on the surface of uncoated particles. The particles of the modified silica sol used in the process of the invention have a specific surface area of about 25 to about 600 square meters per gram with the silica concentration of the sol ranging from about 2 to about 50% by weight.
Inventors
- 👤 Jr George Wallace Sears
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 00:49
CPC Classifications
H; H10; H10P; H10P52/00; H10P52/40; H10P52/402; C; C09; C09K; C09K3/00; C09K3/14; C09K3/1436; C09K3/1445; C09K3/1454; H10P95/00
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
119 words
A PROCESS FOR POLISHING SEMICONDUCTOR MATERIAL SELECTED FROM THE GROUP CONSISTING OF SILICON AND GERMANIUM TO A HIGH DEGREE OF SURFACE PERFECTION COMPRISING POLISHING THE MATERIAL WITH A MODIFIED COLLOIDAL SILICA SOL HAVING A PH BETWEEN ABOUT 11 TO 12.5 IN WHICH THE COLLOIDAL SILICA SOL HAVING A PH BETWEEN WITH CHEMICALLY COMBINATED ATOMS OF ALUMINUM TO GIVE A SURFACE COVERAGE OF ABOUT 1 TO ABOUT 50 ALUMINUM ATOMS ON THE SURFACE PER 100 SILICON ATOMS ON THE SURFACE OF UNCOATED PARTICLES, THE PARTICLES OF SAID MODIFIED SILICA SOL HAVING A SPECIFIC SURFACE AREA OF ABOUT 25 TO ABOUT 600 SQUARE METERS PER GRAM AND SAID SOL HAVING A SILICA CONCENTRATION OF ABOUT 2 TO ABOUT 50% BY WEIGHT.
Claim 2
Dependent Claim
119 words
A PROCESS FOR POLISHING SEMICONDUCTOR MATERIAL SELECTED FROM THE GROUP CONSISTING OF SILICON AND GERMANIUM TO A HIGH DEGREE OF SURFACE PERFECTION COMPRISING POLISHING THE MATERIAL WITH A MODIFIED COLLOIDAL SILICA SOL HAVING A PH BETWEEN ABOUT 11 TO 12.5 IN WHICH THE COLLOIDAL SILICA SOL HAVING A PH BETWEEN WITH CHEMICALLY COMBINATED ATOMS OF ALUMINUM TO GIVE A SURFACE COVERAGE OF ABOUT 1 TO ABOUT 50 ALUMINUM ATOMS ON THE SURFACE PER 100 SILICON ATOMS ON THE SURFACE OF UNCOATED PARTICLES, THE PARTICLES OF SAID MODIFIED SILICA SOL HAVING A SPECIFIC SURFACE AREA OF ABOUT 25 TO ABOUT 600 SQUARE METERS PER GRAM AND SAID SOL HAVING A SILICA CONCENTRATION OF ABOUT 2 TO ABOUT 50% BY WEIGHT.
Claim 3
Dependent Claim
36 words
The process of claim 1 wherein the surface coverage is about 5 to about 40 aluminum atoms per 100 silicon atoms and the silica concentration of the sol is about 5 to about 30% by weight.
Claim 4
Dependent Claim
11 words
The process of claim 1 wherein the semiconductor material is silicon.
Claim 5
Dependent Claim
21 words
The process of claim 2 wherein the surface coverage is about 15 to about 25 aluminum atoms per 100 silicon atoms.
Claim 6
Dependent Claim
28 words
The process of claim 4 wherein the particles of the modified silica sol have a specific surface area of about 50 to about 300 square meters per gram.
Claim 7
Dependent Claim
26 words
The process of claim 4 wherein the particles of said sol have a specific surface area of about 75 to about 200 square meters per gram.
Claim 8
Dependent Claim
11 words
The process of claim 5 wherein the semiconductor material is silicon.
Claim 9
Dependent Claim
13 words
The process of claim 6 wherein the pH is about 11.8 to 12.3.
References Cited (Backward Citations)
US2892797A
Cited
US3170273A
Cited
US3328141A
Cited
US3429080A
Cited
US3527028A
Cited
US3620978A
Cited
US3715842A
Cited
US3745126A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-11-24 | 1979-05-26 | 1979-11-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-11-24 | 1983-05-26 | 1983-11-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-11-24 | 1987-05-26 | 1987-11-25 | $7700.00 | Window Closed / Lapsed |