US4559086A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Backside gettering of silicon wafers utilizing selectively annealed single crystal silicon portions disposed between and extending into polysilicon portions
Assignee: Eastman Kodak Co
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Filing: 1984-07-02
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Granted: 1985-12-17
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Expires: 2004-07-02
Abstract
Abstract There is disclosed a process and the resulting semiconductor wafer wherein the backside of the wafer has applied thereto a layer of polysilicon. Portions of this layer are exposed to an energy beam to recrystallize them into single crystal silicon fused to and extending from the underlying wafer. The recrystallized portions contact adjacent portions of the polysilicon layer, thereby providing a path for impurities migrating from the wafer to the polysilicon.
Inventors
- 👤 Gilbert A. Hawkins
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 05:13
CPC Classifications
H; H10; H10P; H10P36/00; H10P36/03; Y; Y10; Y10S; Y10S148/00; Y10S148/003; Y10S148/024; Y10S148/048; Y10S148/06; Y10S148/061; Y10S148/071; Y10S257/00; Y10S257/928; Y10T; Y10T428/00; Y10T428/26
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
111 words
In a silicon wafer comprising a front side adapted to be made into one or more semiconductor devices, a backside, and a layer of polysilicon in contact with at least a portion of said backside, the improvement comprising spaced-apart portions of single crystal silicon dispersed between and extending into said polysilicon layer, and recrystallized crystal grains transitionally connecting said single crystal portions with portions of said polysilicon layer, said portions of single crystal silicon extending expitaxially from said silicon wafer, whereby said polysilicon portions contacting said single crystal portions act as gettering sites and said single crystal portions act as paths for impurities migrating to said gettering sites from said wafer.
Claim 2
Dependent Claim
111 words
In a silicon wafer comprising a front side adapted to be made into one or more semiconductor devices, a backside, and a layer of polysilicon in contact with at least a portion of said backside, the improvement comprising spaced-apart portions of single crystal silicon dispersed between and extending into said polysilicon layer, and recrystallized crystal grains transitionally connecting said single crystal portions with portions of said polysilicon layer, said portions of single crystal silicon extending expitaxially from said silicon wafer, whereby said polysilicon portions contacting said single crystal portions act as gettering sites and said single crystal portions act as paths for impurities migrating to said gettering sites from said wafer.
Claim 3
Dependent Claim
24 words
A wafer as defined in claim 1, wherein each of said single crystal portions is in contact with polysilicon portions on either side thereof.
Claim 4
Dependent Claim
36 words
A wafer as defined in claim 1, wherein said single crystal portions are between about 1 and about 100 μm wide and are spaced apart, center to center, by between about 50 and about 500 μm.
Claim 5
Dependent Claim
35 words
A wafer as defined in claim 1, wherein said polysilicon layer has a thickness of between about 0.1 μm and about 10 μm and an average grain size of from about 5 to about 5000Å.
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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) | 1988-12-16 | 1989-06-17 | 1989-12-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-12-16 | 1993-06-17 | 1993-12-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-12-16 | 1997-06-17 | 1997-12-17 | $7700.00 | Window Closed / Lapsed |