US3823015A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Photo-masking process
Assignee: Collins Radio Co
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Filing: 1973-01-02
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Granted: 1974-07-09
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Expires: 1993-01-02
Abstract
Abstract A METHOD OF PATTERN DEFINITION EMPLOYING PHOTORESIST MASKING TECHNIQUES USEFUL IN PHOTOENGRAVING GENERALLY AND IN SEMICONDUCTOR PROCESSING SPECIFICALLY WHEREIN DEFECTS DUE TO INHERENT MASK FLAWS ARE MINIMIZED AND MASK TOLERANCE IS IMPROVED INCLUDING THE STEPS OF THRICE DEFINING AND ETCHING A PATTERN DEFINITION LAYER USING SEPARATE PHOTO MASKS OR, WHERE POSSIBLE, BY INDEXING THE SAME PHOTO MASK WHEREBY FLAWS IN THE MASKS DO NOT COINCIDE.
Inventors
- 👤 J Fassett
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 21:10
CPC Classifications
G; G03; G03F; G03F7/00; G03F7/26; H; H10; H10P; H10P95/00
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-07-08 | 1978-01-07 | 1978-07-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-07-08 | 1982-01-07 | 1982-07-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-07-08 | 1986-01-07 | 1986-07-09 | $7700.00 | Window Closed / Lapsed |