US4758368A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for etching silicon wafers using a potassium hydroxide and water etching solution
Assignee: NXP USA Inc
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Filing: 1987-10-19
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Granted: 1988-07-19
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Expires: 2007-10-19
Abstract
Abstract A method for etching silicon wafers having a (100) or (110) crystallographic orientation. The method includes using an etching solution consisting essentially of potassium hydroxide (KOH) and water. This allows for an optimum combination of etch rate and etch quality.
Inventors
- 👤 Patrick Thompson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 17:20
CPC Classifications
C; C09; C09K; C09K13/00; C09K13/02
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
80 words
A method of etching silicon wafers comprising the steps of: providing a silicon wafer having a surface; forming an etch resistant layer on said surface; patterning said etch resistant layer; positioning said wafer into an etching solution of KOH and H 2 O, said etching solution composition being defined by the shaded area 150 of FIG. 3; removing said wafer from said etching solution after said wafer has been etched a predetermined amount. rinsing said etching solution from said wafer.
Claim 2
Independent Claim
80 words
A method of etching silicon wafers comprising the steps of: providing a silicon wafer having a surface; forming an etch resistant layer on said surface; patterning said etch resistant layer; positioning said wafer into an etching solution of KOH and H 2 O, said etching solution composition being defined by the shaded area 150 of FIG. 3; removing said wafer from said etching solution after said wafer has been etched a predetermined amount. rinsing said etching solution from said wafer.
Claim 3
Dependent Claim
20 words
The method of claim 1 wherein said solution consists essentially of 16% KOH and 84% H 2 O by weight.
Claim 4
Dependent Claim
18 words
The method of claim 1 wherein the etching solution further includes 0% to 1.5% isopropyl alcohol by weight.
Claim 5
Dependent Claim
32 words
An etching solution for silicon wafers consisting of KOH, isopropyl alcohol and H 2 O, said etching solution composition being defined by the shaded area 150 of FIG. 3, excluding the y-axis.
Claim 6
Dependent Claim
32 words
An etching solution for silicon wafers consisting of KOH, isopropyl alcohol and H 2 O, said etching solution composition being defined by the shaded area 150 of FIG. 3, excluding the y-axis.
Claim 7
Dependent Claim
20 words
The solution of claim 4 wherein said solution consists essentially of 16% KOH and 84% H 2 O by weight.
Claim 8
Dependent Claim
15 words
The etching solution of claim 4 further including 0% to 1.5% isopropyl alcohol by weight.
References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-07-19 | 1992-01-18 | 1992-07-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-07-19 | 1996-01-18 | 1996-07-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-07-19 | 2000-01-18 | 2000-07-19 | $7700.00 | Window Closed / Lapsed |