US4536251A
Expired / Lapsed
US
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Method for eliminating laser-induced substrate fissures associated with crystallized silicon areas
Assignee: Xerox Corp
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Filing: 1984-06-04
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Granted: 1985-08-20
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Expires: 2004-06-04
Abstract
Abstract A method for eliminating laser induced substrate fissures associated with laser annealed crystallization of patterned silicon areas, for increasing the yield of useable single crystal areas. The fissures are created by enhanced etching of the substrate, at the exposed edges of the areas, during the removal of a dimension stabilizing encapsulating layer. A post crystallization, high temperature anneal, in an oxidizing atmosphere prevents the enhanced etching of the substrate.
Inventors
- 👤 Anne Chiang
- 👤 William P. Meuli
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 07:32
CPC Classifications
C; C30; C30B; C30B29/00; C30B29/60; C30B13/00; C30B29/02; C30B29/06; C30B33/00; H; H10; H10D; H10D86/00; H10D86/01; H10P; H10P34/00; H10P34/40; H10P34/42; H10P95/00; Y; Y10; Y10S; Y10S117/00; Y10S117/903; Y10S117/904
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
98 words
A method for eliminating laser induced substrate fissures associated with crystallized silicon areas comprising the steps of providing a substrate, depositing a layer of polycrystalline semiconductor material upon said substrate, patterning said polycrystalline layer to form an array of areas, depositing an encapsulating layer over said patterned polycrystalline layer, applying thermal energy to said patterned polycrystalline layer for melting said areas and heating said substrate, cooling said areas and said substrate to control resolidification of said areas into single crystals, annealing said areas and said substrate in a heated oxidizing atmosphere, and removing said encapsulating layer by etching.
Claim 2
Independent Claim
98 words
A method for eliminating laser induced substrate fissures associated with crystallized silicon areas comprising the steps of providing a substrate, depositing a layer of polycrystalline semiconductor material upon said substrate, patterning said polycrystalline layer to form an array of areas, depositing an encapsulating layer over said patterned polycrystalline layer, applying thermal energy to said patterned polycrystalline layer for melting said areas and heating said substrate, cooling said areas and said substrate to control resolidification of said areas into single crystals, annealing said areas and said substrate in a heated oxidizing atmosphere, and removing said encapsulating layer by etching.
Claim 3
Dependent Claim
20 words
The method defined in claim 1 wherein said substrate and said polycrystalline semiconductor material have differrent coefficients of thermal expansion.
Claim 4
Dependent Claim
24 words
The method defined in claim 2 wherein said substrate is fused quartz, said encapsulating layer is SiO 2 and said semiconductor material is Si.
Claim 5
Dependent Claim
21 words
The method defined in claim 2 wherein said step of applying thermal energy comprises zone melting of said patterned polycrystalline areas.
Claim 6
Dependent Claim
19 words
The method defined in claim 2 wherein said annealing step comprises passing oxygen over said areas and said substrate.
Claim 7
Dependent Claim
28 words
The method defined in claim 5 wherein said annealing step comprises elevating the temperature of said areas and said substrate into the range from 900° to 1100° C.
Claim 8
Dependent Claim
27 words
The method defined in claim 4 wherein said step of applying thermal energy comprises scanning said areas and said substrate with a continuous wave CO 2 laser.
Claim 9
Dependent Claim
20 words
The method defined in claim 7 wherein said laser energy is applied in the range from 2.6 to 2.9 watts.
Claim 10
Dependent Claim
16 words
The method defined in claim 5 wherein said removing step comprises using an HF based etchant.
Claim 11
Dependent Claim
19 words
The method defined in claim 2 wherein said annealing step comprises passing steam over said areas and said substrate.
References Cited (Backward Citations)
US4330363A
Cited
US4388145A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-08-19 | 1989-02-18 | 1989-08-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-08-19 | 1993-02-18 | 1993-08-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-08-19 | 1997-02-18 | 1997-08-20 | $7700.00 | Window Closed / Lapsed |