Patent US5478758A successfully refreshed from Google Patents.
US5478758A
Expired / Lapsed
US
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Method of making a getterer for multi-layer wafers
Assignee: AT&T Inc
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Filing: 1994-06-03
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Granted: 1995-12-26
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Expires: 2014-06-03
Abstract
Abstract A method of making a gettering structure for dielectrically isolated wafer structures, such as bonded wafers. A getterer layer is deposited over the wafer having semiconductor regions isolated from each other by trenches. The polysilicon is etched back leaving the polysilicon on the sides of the regions. The polysilicon may be doped. The polysilicon is oxidized and a second layer of polysilicon may be deposited to fill voids in the trenches.
Inventors
- 👤 William G. Easter
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 05:10
CPC Classifications
H; H10; H10P; H10P36/00; H10P36/03; H10P36/07; H10P90/00; H10P90/19; H10P90/1904; H10P90/1906; H10P90/1914; H10W; H10W10/00; H10W10/10; H10W10/181; Y; Y10; Y10S; Y10S148/00; Y10S148/05
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
71 words
A method of making a wafer, the wafer having a working layer and a handle layer, CHARACTERIZED BY THE STEPS OF: trenching the working layer to form portions thereof having minor surfaces; depositing polysilicon over the working layer and in the trenches to cover the minor surfaces; and etching the polysilicon back to retain the polysilicon on the minor surfaces; wherein the polysilicon on the minor surfaces is a gettering layer.
Claim 2
Independent Claim
71 words
A method of making a wafer, the wafer having a working layer and a handle layer, CHARACTERIZED BY THE STEPS OF: trenching the working layer to form portions thereof having minor surfaces; depositing polysilicon over the working layer and in the trenches to cover the minor surfaces; and etching the polysilicon back to retain the polysilicon on the minor surfaces; wherein the polysilicon on the minor surfaces is a gettering layer.
Claim 3
Dependent Claim
27 words
The method recited in claim 1, further characterized by the steps of: forming an oxide on at least said gettering layer; and filling the trench with polysilicon.
Claim 4
Dependent Claim
47 words
The method recited in claim 2, wherein the step of filling the trench with polysilicon is further characterized by the steps of: depositing polysilicon over the working layer to ensure the filling of the trenches; and etching back the polysilicon to leave the polysilicon in the trenches.
Claim 5
Dependent Claim
12 words
The method recited in claim 3, wherein the oxide is thermally grown.
Claim 6
Dependent Claim
12 words
The method recited in claim 4, wherein said gettering layer is doped.
Claim 7
Dependent Claim
14 words
The method recited in claim 3, wherein said gettering layer is doped with phosphorus.
Claim 8
Dependent Claim
34 words
The method recited in claim 3, wherein the handle layer and the working layer are separated by an insulating layer and the the filled trench extends through the working layer to the insulating layer.
Claim 9
Dependent Claim
20 words
The method recited in claim 7, wherein the insulating layer is silicon dioxide and the wafer is a bonded wafer.
Claim 10
Independent Claim
108 words
A method of making a wafer, the wafer having a working layer and a handle layer separated from the working layer by an insulating layer, CHARACTERIZED BY THE STEPS OF: trenching the working layer to form portions thereof having minor surfaces, the trench extending to the insulating layer; depositing a polysilicon gettering layer on at least one of the minor surfaces; etching the polysilicon back to retain the polysilicon on the minor surfaces; forming an oxide on at least the polysilicon gettering layer; depositing polysilicon over the working layer to ensure the filling of the trenching and etching back the polysilicon to leave the polysilicon in the trenches.
Claim 11
Independent Claim
108 words
A method of making a wafer, the wafer having a working layer and a handle layer separated from the working layer by an insulating layer, CHARACTERIZED BY THE STEPS OF: trenching the working layer to form portions thereof having minor surfaces, the trench extending to the insulating layer; depositing a polysilicon gettering layer on at least one of the minor surfaces; etching the polysilicon back to retain the polysilicon on the minor surfaces; forming an oxide on at least the polysilicon gettering layer; depositing polysilicon over the working layer to ensure the filling of the trenching and etching back the polysilicon to leave the polysilicon in the trenches.
Claim 12
Dependent Claim
12 words
The method recited in claim 9, wherein the oxide is thermally grown.
Claim 13
Dependent Claim
13 words
The method recited in claim 10, wherein the polysilicon gettering layer is doped.
Claim 14
Dependent Claim
13 words
The method recited in claim 11, wherein the polysilicon dopant is a phosphorus.
Claim 15
Dependent Claim
13 words
The method recited in claim 9, wherein the wafer is a bonded wafer.
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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) | 1998-12-25 | 1999-06-26 | 1999-12-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-12-25 | 2003-06-26 | 2003-12-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-12-25 | 2007-06-26 | 2007-12-26 | $7700.00 | Window Closed / Lapsed |