US5207866A
Expired / Lapsed
US
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Anisotropic single crystal silicon etching solution and method
Assignee: NXP USA Inc
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Filing: 1991-01-17
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Granted: 1993-05-04
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Expires: 2011-01-17
Abstract
Abstract A method of anisotropically etching single crystal silicon includes providing single crystal silicon to be etched and placing it in an etching solution consisting essentially of R 4 NOH and solvent wherein R is an alkyl group having between 0 and 4 carbon atoms. The solution will preferentially etch <100> or <110> oriented single crystal silicon. Additionally, electrochemical etching may be employed to preferentially etch P type single crystal silicon.
Inventors
- 👤 Ping-Chang Lue
- 👤 Henry G. Hughes
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 15:49
CPC Classifications
H; H10; H10P; H10P90/00; H10P90/12; H10P90/126; H10P50/00; H10P50/60; H10P50/64; H10P50/642; H10P50/644
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
59 words
An electrochemical method of anisotropically etching single crystal silicon comprising the steps of: providing single crystal silicon to be etched; and anisotropically etching said silicon in an electrochemical bath having an etching solution consisting essentially of more than 20% by weight R 4 NOH and solvent wherein R is an alkyl group having between 0 and 4 carbon atoms.
Claim 2
Dependent Claim
59 words
An electrochemical method of anisotropically etching single crystal silicon comprising the steps of: providing single crystal silicon to be etched; and anisotropically etching said silicon in an electrochemical bath having an etching solution consisting essentially of more than 20% by weight R 4 NOH and solvent wherein R is an alkyl group having between 0 and 4 carbon atoms.
Claim 3
Dependent Claim
18 words
The method of claim 1 wherein the silicon is preferentially etched in the <100> and <100> crystallographic orientations.
Claim 4
Dependent Claim
12 words
The method of claim 1 wherein the solvent comprises H 2 O.
Claim 5
Dependent Claim
12 words
The method of claim 3 wherein P type silicon is preferentially etched.
Claim 6
Dependent Claim
18 words
The method of claim 4 wherein the temperature of the etching solution is at least 50 degrees centigrade.
Claim 7
Dependent Claim
82 words
An electrochemical method of preferentially etching single crystal silicon having a <100> or <110> crystallographic orientation comprising the steps of: providing single crystal silicon having a <100> or <110> crystallographic orientation to be etched; and preferentially etching said silicon in an electrochemical bath having an etching solution consisting essentially of R 4 NOH and H 2 O wherein R is an alkyl group having between 0 and 4 carbon atoms and said solution comprises more than 20% R 4 NOH by weight.
Claim 8
Dependent Claim
82 words
An electrochemical method of preferentially etching single crystal silicon having a <100> or <110> crystallographic orientation comprising the steps of: providing single crystal silicon having a <100> or <110> crystallographic orientation to be etched; and preferentially etching said silicon in an electrochemical bath having an etching solution consisting essentially of R 4 NOH and H 2 O wherein R is an alkyl group having between 0 and 4 carbon atoms and said solution comprises more than 20% R 4 NOH by weight.
Claim 9
Dependent Claim
18 words
The method of claim 6 wherein the temperature of the etching solution is at least 50 degrees centigrade.
Claim 10
Dependent Claim
12 words
The method of claim 7 wherein P type silicon is preferentially etched.
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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) | 1996-05-03 | 1996-11-02 | 1997-05-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-05-03 | 2000-11-02 | 2001-05-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-05-03 | 2004-11-02 | 2005-05-04 | $7700.00 | Window Closed / Lapsed |