Patent US6927116B2 successfully refreshed from Google Patents.
US6927116B2
Expired / Lapsed
US
⏱️ 0.0 years remaining
Semiconductor device having a double-well structure and method for manufacturing the same
Assignee: Toshiba Corp
•
Filing: 2001-12-11
•
Granted: 2005-08-09
•
Expires: 2021-12-11
Abstract
Abstract A first well of the same conductivity type as that of a semiconductor substrate and a second well of a conductivity type opposite to that of the semiconductor substrate, are formed in the semiconductor substrate. The second well isolates the semiconductor substrate and the first well from each other. Phosphorus ions for forming the bottom of the second well are implanted into the semiconductor substrate more deeply than boron ions for forming the first well. The depths to which these ions are implanted can be varied by acceleration energy of the ions. If the ions are so implanted, the total sum of impurities constituting the second well can be decreased within the surface area of the first well.
Inventors
- 👤 Norihisa Arai
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 20:06
CPC Classifications
H; H10; H10D; H10D84/00; H10D84/01; H10D84/0123; H10D84/0126; H10D84/0165; H10D84/0191; H10D84/02; H10D84/03; H10D84/038; H10D84/80; H10D84/82; H10D84/83; H10D84/85; H10D84/859
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
165 words
A method for manufacturing a semiconductor device, comprising: implanting first conductivity type impurity ions and second conductivity type impurity ions through a first area exposed by a first mask and into a first well forming region of a semiconductor substrate of a first conductivity type, said first conductivity type impurity ions constituting a first well and being shallower than the second conductivity type impurity ions; masking, by a second mask, at least a portion of the first area exposed by the first mask; implanting additional impurity ions of said second conductivity type through a second area exposed by the second mask and into a region around said first well forming region, said additional second conductivity type impurity ions and said second conductivity type impurity ions implanted below the first conductivity type impurity ions constituting a second well and activating said first conductivity type impurity ions and said second conductivity type impurity ions to form the first well and the second well in said semiconductor substrate.
Claim 2
Independent Claim
165 words
A method for manufacturing a semiconductor device, comprising: implanting first conductivity type impurity ions and second conductivity type impurity ions through a first area exposed by a first mask and into a first well forming region of a semiconductor substrate of a first conductivity type, said first conductivity type impurity ions constituting a first well and being shallower than the second conductivity type impurity ions; masking, by a second mask, at least a portion of the first area exposed by the first mask; implanting additional impurity ions of said second conductivity type through a second area exposed by the second mask and into a region around said first well forming region, said additional second conductivity type impurity ions and said second conductivity type impurity ions implanted below the first conductivity type impurity ions constituting a second well and activating said first conductivity type impurity ions and said second conductivity type impurity ions to form the first well and the second well in said semiconductor substrate.
Claim 3
Dependent Claim
63 words
A method according to claim 1 , wherein the first conductivity type impurity ions are implanted to a first depth from a surface of the semiconductor substrate, the second conductivity type impurity ions below the first conductivity type impurity ions are implanted to a second depth from the surface of the semiconductor substrate, and the second depth is greater than the first depth.
Claim 4
Dependent Claim
35 words
A method according to claim 1 , wherein the additional second conductivity type impurity ions around the first well forming region are implanted uniformly within a range from the second depth to the first depth.
Claim 5
Dependent Claim
37 words
A method according to claim 3 , wherein the first depth and the second depth to which the first conductivity type impurity ions and the second conductivity type impurity ions are implanted, are controlled by acceleration energy.
Claim 6
Dependent Claim
36 words
A method according to claim 4 , further comprising forming an element isolating oxide film on the surface of the semiconductor substrate before the additional second impurity ions are implanted around the first well forming region.
Claim 7
Dependent Claim
36 words
A method according to claim 4 , further comprising forming an element isolating oxide film on the surface of the semiconductor substrate after the additional second impurity ions are implanted around the first well forming region.
Claim 8
Dependent Claim
72 words
A method according to claim 4 , further comprising: forming an element isolating oxide film on the surface of the semiconductor substrate after the additional second impurity ions are implanted around the first well forming region; forming a gate oxide film on the surface of the semiconductor substrate; and implanting said first conductivity type impurity ions and second conductivity type impurity ions using the first mask after forming the gate oxide film.
Claim 9
Dependent Claim
25 words
A method according to claim 7 , further comprising annealing to diffuse the first conductivity type impurity ions and the second conductivity type impurity ions.
Claim 10
Dependent Claim
24 words
A method according to claim 7 , wherein said first well and a part of the second well are formed using said first mask.
Claim 11
Dependent Claim
31 words
A method according to claim 1 , wherein the additional second impurity ions around the first well forming region are implanted into the substrate plural times by changing the acceleration energy.
Claim 12
Dependent Claim
23 words
A method according to claim 1 , wherein the first well constitutes a P-type well and the second well constitutes an N-type well.
Claim 13
Dependent Claim
31 words
The method according to claim 1 , wherein the steps of implanting result in a bottom of said second well having a substantially uniform depth from a surface of said substrate.
References Cited (Backward Citations)
JPS6179250A
Cited
JPS61125071A
Cited
JPS61242064A
Cited
JPS63102370A
Cited
US4898836A
Cited
JPH0492466A
Cited
JPH04199706A
Cited
JPH06260607A
Cited
US5780907A
Cited
US5990535A
Cited
US5573962A
Cited
US5729056A
Cited
US5547894A
Cited
US5702988A
Cited
US6342719B1
Cited
US6750527B1
Cited
US5943581A
Cited
US5994177A
Cited
US6124618A
Cited
US6693331B2
Cited
US6803285B2
Cited
US6543393B1
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2008-08-08 | 2009-02-07 | 2009-08-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2012-08-08 | 2013-02-07 | 2013-08-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2016-08-08 | 2017-02-07 | 2017-08-09 | $7700.00 | Window Closed / Lapsed |