Patent US4518456A successfully refreshed from Google Patents.
US4518456A
Expired / Lapsed
US
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Light induced etching of InP by aqueous solutions of H3 PO4
Assignee: Nokia Bell Labs
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Filing: 1983-03-11
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Granted: 1985-05-21
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Expires: 2003-03-11
Abstract
Abstract A method of etching a semiconductor crystal is given. The crystal includes elements selected from one of the groups: (a) indium and phosphorus; (b) gallium and arsenic; (c) aluminum and arsenic. The method comprises the steps of placing the crystal in an aqueous solution of H3PO4 or HCl, and while the crystal is in contact with the solution illuminating predetermined regions of the crystal with light so that etching proceeds at the illuminated predetermined regions much more rapidly than at nonilluminated regions of the crystal. The method also includes focusing the light to a small spot on the crystal and moving the spot on the crystal so that a groove is etched in the crystal.
Inventors
- 👤 John E. Bjorkholm
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 13:59
CPC Classifications
H; H10; H10P; H10P50/00; H10P50/60; H10P50/64; H10P50/642; H10P50/646; Y; Y10; Y10S; Y10S148/00; Y10S148/093
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
89 words
A method of etching a predetermined pattern into a Group III-V semiconductor crystal comprising the steps of: placing said crystal in an aqueous solution of H 3 PO 4 ; while said crystal is in contact with said solution, illuminating predetermined regions of said crystal with light so that etching proceeds at said illuminated predetermined regions; focusing said light to a spot having a spot size less than 500 Angstroms on said crystal; and moving said spot on said crystal so that a groove is etched in said crystal.
Claim 2
Independent Claim
89 words
A method of etching a predetermined pattern into a Group III-V semiconductor crystal comprising the steps of: placing said crystal in an aqueous solution of H 3 PO 4 ; while said crystal is in contact with said solution, illuminating predetermined regions of said crystal with light so that etching proceeds at said illuminated predetermined regions; focusing said light to a spot having a spot size less than 500 Angstroms on said crystal; and moving said spot on said crystal so that a groove is etched in said crystal.
Claim 3
Dependent Claim
21 words
The method as claimed in claim 1 wherein said moving said spot on said crystal is done by moving said crystal.
Claim 4
Dependent Claim
26 words
The method as claimed in claim 1 wherein said moving said spot on said crystal is done by scanning a light beam which provides said light.
Claim 5
Independent Claim
67 words
A method of etching a predetermined pattern into a Group III-V semiconductor crystal comprising the steps of: placing said crystal in an aqueous solution of H 3 PO 4 ; while said crystal is in contact with said solution, generating a standing wave pattern of light on a surface of said crystal so that etching proceeds at the location of bright regions of said standing wave pattern.
Claim 6
Independent Claim
67 words
A method of etching a predetermined pattern into a Group III-V semiconductor crystal comprising the steps of: placing said crystal in an aqueous solution of H 3 PO 4 ; while said crystal is in contact with said solution, generating a standing wave pattern of light on a surface of said crystal so that etching proceeds at the location of bright regions of said standing wave pattern.
Claim 7
Independent Claim
95 words
A method of etching a predetermined pattern of grooves into a Group III-V semiconductor crystal comprising the steps of: spacing said crystal in an aqueous solution of H 3 PO 4 ; while said crystal is in contact with said solution, illuminating regions of said crystal with light; directing said light through a pattern which has opaque areas and transparent areas so that said light illuminates said regions of said crystal in accordance with said pattern, and etching of said grooves proceeds at said illuminated regions, wherein said pattern is spaced apart from said crystal.
Claim 8
Independent Claim
95 words
A method of etching a predetermined pattern of grooves into a Group III-V semiconductor crystal comprising the steps of: spacing said crystal in an aqueous solution of H 3 PO 4 ; while said crystal is in contact with said solution, illuminating regions of said crystal with light; directing said light through a pattern which has opaque areas and transparent areas so that said light illuminates said regions of said crystal in accordance with said pattern, and etching of said grooves proceeds at said illuminated regions, wherein said pattern is spaced apart from said crystal.
Claim 9
Independent Claim
80 words
A method of etching a Group III-V semiconductor crystal comprising: placing said crystal in an etchant of an aqueous solution of H 3 PO 4 ; while said crystal is in contact with said solution, illuminating said crystal with light; detecting a portion of said light which penetrates said crystal; and controlling the intensity of said light in response to the detected portion of said light so that at least one region of predetermined thickness is etched in said crystal.
Claim 10
Independent Claim
80 words
A method of etching a Group III-V semiconductor crystal comprising: placing said crystal in an etchant of an aqueous solution of H 3 PO 4 ; while said crystal is in contact with said solution, illuminating said crystal with light; detecting a portion of said light which penetrates said crystal; and controlling the intensity of said light in response to the detected portion of said light so that at least one region of predetermined thickness is etched in said crystal.
Claim 11
Dependent Claim
19 words
The method of etching a crystal as in claim 6 wherein said crystal has a hole etched through it.
References Cited (Backward Citations)
US3887404A
Cited
US4351706A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-05-20 | 1988-11-19 | 1989-05-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-05-20 | 1992-11-19 | 1993-05-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-05-20 | 1996-11-19 | 1997-05-21 | $7700.00 | Window Closed / Lapsed |