US5773335A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for forming twin-tub wells in substrate
Assignee: United Microelectronics Corp
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Filing: 1996-08-20
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Granted: 1998-06-30
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Expires: 2016-08-20
Abstract
Abstract A method for forming twin-tub wells in a semiconductor substrate is disclosed. The present invention includes forming a first silicon oxide layer on the substrate. A silicon nitride layer is patterned on a portion of the first silicon oxide layer by a photoresist mask. First-type ions are implanted over the substrate not covered by the silicon nitride layer. Next, a second silicon oxide layer formed by a liquid phase deposition method is deposited on a portion of the first silicon oxide layer not covered by the silicon nitride layer. After the silicon nitride layer is removed, second-type ions are implanted over the substrate not covered by the second silicon oxide layer. Finally, the substrate is drived-in such that a first-type well and a second-type well are formed under the first silicon oxide layer.
Inventors
- 👤 Fang-Ching Chao
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 12:08
CPC Classifications
H; H10; H10D; H10D84/00; H10D84/01; H10D84/0123; H10D84/0126; H10D84/0165; H10D84/0191; H10D84/02; H10D84/03; H10D84/038; Y; Y10; Y10S; Y10S438/00; Y10S438/914; Y10S438/919
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
159 words
A method for forming twin-tub wells in a substrate, said method comprising: forming a first silicon oxide layer on the substrate; patterning a silicon nitride layer on a portion of said first silicon oxide layer using a photoresist mask; implanting a plurality of first-type ions over the substrate not covered by said silicon nitride layer; forming a second silicon oxide layer on a portion of said first silicon oxide layer not covered by said silicon nitride layer, said second silicon oxide layer being formed by a liquid phase deposition; driving-in the substrate such that a first-type well is formed under said first silicon oxide layer covered by said second silicon oxide layer, removing said silicon nitride layer; implanting a plurality of second-type ions over the substrate not covered by said second silicon oxide layer; and driving-in the substrate such that a second-type well is formed under said first silicon oxide layer not covered by said second silicon oxide layer.
Claim 2
Independent Claim
159 words
A method for forming twin-tub wells in a substrate, said method comprising: forming a first silicon oxide layer on the substrate; patterning a silicon nitride layer on a portion of said first silicon oxide layer using a photoresist mask; implanting a plurality of first-type ions over the substrate not covered by said silicon nitride layer; forming a second silicon oxide layer on a portion of said first silicon oxide layer not covered by said silicon nitride layer, said second silicon oxide layer being formed by a liquid phase deposition; driving-in the substrate such that a first-type well is formed under said first silicon oxide layer covered by said second silicon oxide layer, removing said silicon nitride layer; implanting a plurality of second-type ions over the substrate not covered by said second silicon oxide layer; and driving-in the substrate such that a second-type well is formed under said first silicon oxide layer not covered by said second silicon oxide layer.
Claim 3
Dependent Claim
24 words
The method according to claim 1, after the drive-in step, further comprising removing said second silicon oxide layer and said first silicon oxide layer.
Claim 4
Dependent Claim
13 words
The method according to claim 1, wherein the substrate is a p-type substrate.
Claim 5
Dependent Claim
13 words
The method according to claim 1, wherein the substrate is an n-type substrate.
Claim 6
Independent Claim
155 words
A method for forming twin-tub wells in a substrate, said method comprising: forming a first silicon oxide layer on the substrate; patterning a dielectric layer on a portion of said first silicon oxide layer using a photoresist mask; implanting a plurality of first-type ions over the substrate not covered by said dielectric layer; forming a second silicon oxide layer on a portion of said first silicon oxide layer not covered by said dielectric layer, said second silicon oxide layer being formed by a liquid phase deposition; driving-in the substrate such that a first-type well is formed under said first silicon oxide layer covered by said second silicon oxide layer; removing said dielectric layer; implanting a plurality of second-type ions over the substrate not covered by said second silicon oxide layer; and driving-in the substrate such that a second-type well is formed under said first silicon oxide layer not covered by said second silicon oxide layer.
Claim 7
Independent Claim
155 words
A method for forming twin-tub wells in a substrate, said method comprising: forming a first silicon oxide layer on the substrate; patterning a dielectric layer on a portion of said first silicon oxide layer using a photoresist mask; implanting a plurality of first-type ions over the substrate not covered by said dielectric layer; forming a second silicon oxide layer on a portion of said first silicon oxide layer not covered by said dielectric layer, said second silicon oxide layer being formed by a liquid phase deposition; driving-in the substrate such that a first-type well is formed under said first silicon oxide layer covered by said second silicon oxide layer; removing said dielectric layer; implanting a plurality of second-type ions over the substrate not covered by said second silicon oxide layer; and driving-in the substrate such that a second-type well is formed under said first silicon oxide layer not covered by said second silicon oxide layer.
Claim 8
Dependent Claim
24 words
The method according to claim 5, after the drive-in step, further comprising removing said second silicon oxide layer and said first silicon oxide layer.
Claim 9
Dependent Claim
14 words
The method according to claim 5, wherein the substrate is a P type substrate.
Claim 10
Dependent Claim
13 words
The method according to claim 5, wherein the substrate is an n-type substrate.
Claim 11
Dependent Claim
14 words
The method according to claim 5, wherein said dielectric layer is a polysilicon layer.
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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) | 2001-06-29 | 2001-12-29 | 2002-06-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-06-29 | 2005-12-29 | 2006-06-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-06-29 | 2009-12-29 | 2010-06-30 | $7700.00 | Window Closed / Lapsed |