US4737468A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for developing implanted buried layer and/or key locators
Assignee: NXP USA Inc
•
Filing: 1987-04-13
•
Granted: 1988-04-12
•
Expires: 2007-04-13
Abstract
Abstract The present invention consists of a process of blanket implanting a key area and buried layer without the use of nitride or thick oxide layers. The key area is then etched leaving the surface of the key area below the surface of the buried layer. Upon growing an epitaxial layer, the key area will be identifiable by a step in the surface of the epi layer.
Inventors
- 👤 John E. Martin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 15:43
CPC Classifications
H; H10; H10W; H10W46/00; H10W15/00; H10W15/01; H10W46/501; Y; Y10; Y10S; Y10S438/00; Y10S438/975
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
113 words
A process for developing implanted buried layers and key locators in a substrate comprising the steps of: growing or depositing a screen oxide on said substrate; depositing a first photoresist on said screen oxide; developing said first photoresist, exposing a key area of said screen oxide and said substrate; etching said key area of said screen oxide and said substrate; removing said first photoresist; depositing a second photoresist on said screen oxide; developing said second photoresist, exposing said key area of said substrate and a buried layer area of said screen oxide; and implanting said key area and said buried layer area of said substrate with a dopant of a first conductivity type.
Claim 2
Dependent Claim
113 words
A process for developing implanted buried layers and key locators in a substrate comprising the steps of: growing or depositing a screen oxide on said substrate; depositing a first photoresist on said screen oxide; developing said first photoresist, exposing a key area of said screen oxide and said substrate; etching said key area of said screen oxide and said substrate; removing said first photoresist; depositing a second photoresist on said screen oxide; developing said second photoresist, exposing said key area of said substrate and a buried layer area of said screen oxide; and implanting said key area and said buried layer area of said substrate with a dopant of a first conductivity type.
Claim 3
Dependent Claim
22 words
The process of claim 1 further comprising the steps of: removing said second photoresist; and growing an epitaxial layer on said substrate.
Claim 4
Dependent Claim
58 words
The process of claim 2 further comprising, following the step of removing said second photoresist, the steps of: depositing a third photoresist on said substrate; developing said third photoresist, exposing a channel stop area of said substrate; implanting said channel stop area of said substrate with a dopant of a second conductivity type; and removing said third photoresist.
Claim 5
Dependent Claim
29 words
The process of claim 3 wherein said dopant of a first conductivity type is a p-type dopant and said dopant of a second conductivity type is an n-type dopant.
Claim 6
Dependent Claim
29 words
The process of claim 3 wherein said dopant of a first conductivity type is an n-type dopant and said dopant of a second conductivity type is a p-type dopant.
Claim 7
Dependent Claim
106 words
A process for developing implanted buried layers and key locators in a substrate comprising the steps of: depositing or growing a screen oxide on said substrate; depositing a first photoresist on said screen oxide; developing said first photoresist, exposing a key area and a buried layer area of said screen oxide and said substrate; implanting said key area and said buried layer area of said oxide and said substrate with a dopant of a first conductivity type; depositing a second photoresist; developing said second photoresist, exposing said key area of said oxide and said substrate; and etching said key area of said oxide and said substrate.
Claim 8
Dependent Claim
106 words
A process for developing implanted buried layers and key locators in a substrate comprising the steps of: depositing or growing a screen oxide on said substrate; depositing a first photoresist on said screen oxide; developing said first photoresist, exposing a key area and a buried layer area of said screen oxide and said substrate; implanting said key area and said buried layer area of said oxide and said substrate with a dopant of a first conductivity type; depositing a second photoresist; developing said second photoresist, exposing said key area of said oxide and said substrate; and etching said key area of said oxide and said substrate.
Claim 9
Dependent Claim
30 words
The process of claim 6 further comprising the steps of: removing said second photoresist; removing said first photoresist; removing said screen oxide; and growing an epitaxial layer on said substrate.
Claim 10
Dependent Claim
69 words
The process of claim 7 further comprising, following the step of removing said first photoresist, the steps of: depositing a third photoresist on said oxide; developing said third photoresist, exposing a channel stop area of said oxide and said substrate; etching said channel stop area of said oxide; implanting said channel stop area of said substrate with a dopant of a second conductivity type; and removing said third photoresist.
Claim 11
Dependent Claim
29 words
The process of claim 8 wherein said dopant of a first conductivity type is a p-type dopant and said dopant of a second conductivity type is an n-type dopant.
Claim 12
Dependent Claim
29 words
The process of claim 8 wherein said dopant of a first conductivity type is an n-type dopant and said dopant of a second conductivity type is a p-type dopant.
References Cited (Backward Citations)
US918008A
Cited
US3648128A
Cited
US4272776A
Cited
UST918008I4
Cited
US4253888A
Cited
US4242791A
Cited
US4341571A
Cited
US4398964A
Cited
US4546534A
Cited
US4517731A
Cited
US4487653A
Cited
US4573257A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-04-12 | 1991-10-12 | 1992-04-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-04-12 | 1995-10-12 | 1996-04-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-04-12 | 1999-10-12 | 2000-04-12 | $7700.00 | Window Closed / Lapsed |