US4925809A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Semiconductor wafer and epitaxial growth on the semiconductor wafer with autodoping control and manufacturing method therefor
Assignee: Sumco Corp
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Filing: 1988-07-01
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Granted: 1990-05-15
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Expires: 2008-07-01
Abstract
Abstract A semiconductor wafer on which silicon or the like is epitaxially grown and p-type or n-type impurities are doped and which has at the rear surface except for the peripheral edge portion thereof a blocking film for preventing jumping out of impurities therefrom which causes auto-doping, thereby preventing silicon particles from being produced at the peripheral surface and preventing the semiconductor wafer from being contaminated by the silicon particles during the manufacturing of a semiconductor device.
Inventors
- 👤 Tetsujiro Yoshiharu
- 👤 Haruo Kamise
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 19:27
CPC Classifications
H; H10; H10P; H10P14/00; H10P14/60; H10P14/63; H10P14/6326; H10P14/6328; H10P14/6334; H10P32/00; H10P32/10; H10P32/15; H10P50/00; H10P50/20; H10P50/28; H10P50/282; H10P50/283; H10P14/69; H10P14/692; H10P14/6921; H10P14/69215; H10P14/694; H10P14/6943; H10P14/69433; Y; Y10; Y10S; Y10S148/00; Y10S148/161; Y10S438/00; Y10S438/914; Y10S438/916; Y10S438/959
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
77 words
A manufacturing method for a semiconductor wafer, comprising the steps of forming a blocking film on the entirety of one of two opposite flat surfaces of said semiconductor wafer and along a peripheral surface thereof, and removing said blocking film from said peripheral surface, characterized by the further step of producing an epitaxial layer on the surface opposite said one flat surface, at which time said blocking film prevents volatilization of impurities which would otherwise cause autodoping.
Claim 2
Dependent Claim
77 words
A manufacturing method for a semiconductor wafer, comprising the steps of forming a blocking film on the entirety of one of two opposite flat surfaces of said semiconductor wafer and along a peripheral surface thereof, and removing said blocking film from said peripheral surface, characterized by the further step of producing an epitaxial layer on the surface opposite said one flat surface, at which time said blocking film prevents volatilization of impurities which would otherwise cause autodoping.
Claim 3
Dependent Claim
33 words
A manufacturing method for a semiconductor wafer as set forth in claim 1, wherein the peripheral surface of said semiconductor wafer is formed arcuated in section prior to formation of said blocking film.
Claim 4
Dependent Claim
23 words
A manufacturing method for a semiconductor wafer as set forth in claim 1, wherein said blocking film is formed by a CVD method.
Claim 5
Dependent Claim
74 words
A manufacturing method for a semiconductor wafer as set forth in claim 1, wherein said semiconductor is disc-shaped, and cloth permeated with an etchant for said blocking film is brought into contact with said blocking film while said semiconductor wafer having said blocking film formed thereon is being rotated around the center of the plane of said semiconductor wafer as the axis of rotation thereof, thereby removing said blocking film from said semiconductor wafer.
Claim 6
Dependent Claim
19 words
A manufacturing method for a semiconductor wafer as set forth in claim 4, wherein said cloth is non-woven fabric.
Claim 7
Dependent Claim
65 words
A manufacturing method for a semiconductor wafer as set forth in claim 1, wherein said semiconductor wafer is disc-shaped and a polishing grindstone is brought into contact with said blocking film while said semiconductor wafer on which said blocking film is formed is being rotated around the center of the plane as the axis of rotation, thereby removing said blocking film from said semiconductor 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) | 1993-05-14 | 1993-11-13 | 1994-05-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-05-14 | 1997-11-13 | 1998-05-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-05-14 | 2001-11-13 | 2002-05-15 | $7700.00 | Window Closed / Lapsed |