US3998653A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for cleaning semiconductor devices
Assignee: General Electric Co
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Filing: 1976-03-09
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Granted: 1976-12-21
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Expires: 1996-03-09
Abstract
Abstract A solution of potassium hydroxide is employed to remove the reaction products of aluminum migrated through silicon-semiconductor material by thermal gradient zone melting processing.
Inventors
- 👤 Thomas R. Anthony
- 👤 Harvey E. Cline
- 👤 Mike F. Chang
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 20:09
CPC Classifications
H; H10; H10P; H10P50/00; B; B08; B08B; B08B3/00; B08B3/04; B08B3/10; B08B3/12
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
128 words
A method for removing reaction products produced on surface areas of a silicon wafer by the reaction of molten aluminum with silicon oxide and silicon on said surface areas including the steps of preparing a bath of a selective chemical etchant comprising a solution of potassium hydroxide in water wherein the concentration of the potassium hydroxide is from 2 to 67 percent by weight; heating the bath to a temperature of at least 80° C; placing said silicon wafer in the bath; removing at least a portion of the reaction products and a selected portion of silicon base material from surface areas of the said wafer by selective chemical etching in the bath; and removing a portion of the reaction products from said etched wafer by mechanical agitation.
Claim 2
Independent Claim
128 words
A method for removing reaction products produced on surface areas of a silicon wafer by the reaction of molten aluminum with silicon oxide and silicon on said surface areas including the steps of preparing a bath of a selective chemical etchant comprising a solution of potassium hydroxide in water wherein the concentration of the potassium hydroxide is from 2 to 67 percent by weight; heating the bath to a temperature of at least 80° C; placing said silicon wafer in the bath; removing at least a portion of the reaction products and a selected portion of silicon base material from surface areas of the said wafer by selective chemical etching in the bath; and removing a portion of the reaction products from said etched wafer by mechanical agitation.
Claim 3
Dependent Claim
21 words
The method of claim 1 wherein the temperature of the bath is approximately that of the boiling point of the solution.
Claim 4
Dependent Claim
26 words
The method of claim 1 wherein the removal of a portion of the reaction products by agitation is practiced in a separate bath of deionized water.
Claim 5
Dependent Claim
21 words
The method of claim 1 wherein the percentage of weight of potassium hydroxide in the solution is from 45 to 55.
Claim 6
Dependent Claim
19 words
The method of claim 4 wherein the percentage by weight of potassium hydroxide in the solution is about 50%.
Claim 7
Dependent Claim
18 words
The method of claim 4 wherein the temperature of the bath is about 110° C ± 5° C.
Claim 8
Dependent Claim
20 words
The method of claim 2 wherein the temperature of the bath is from about 101° C to about 127° C.
Claim 9
Dependent Claim
61 words
The method of claim 4 wherein the temperature of the bath is approximately that of the boiling point of the solution, etching in the bath is practiced for about 3 minutes, and the removal of a portion of the reaction products by agitation is practiced in a separate bath of deionized water for a period from about 1 to 3 minutes.
Claim 10
Dependent Claim
13 words
The method of claim 8 wherein said agitation is produced by ultrasonic energy.
Claim 11
Dependent Claim
19 words
The method of claim 9 wherein the percent of potassium hydroxide by weight in the solution is about 50.
Claim 12
Dependent Claim
13 words
The method of claim 8 wherein said agitation is produced by mechanical scrubbing.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-12-21 | 1980-06-21 | 1980-12-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-12-21 | 1984-06-21 | 1984-12-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-12-21 | 1988-06-21 | 1988-12-21 | $7700.00 | Window Closed / Lapsed |