US3823016A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Photomask repair process
Assignee: International Business Machines Corp
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Filing: 1973-05-03
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Granted: 1974-07-09
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Expires: 1993-05-03
Abstract
Abstract DEFECTS IN EXPOSURE MASKS USED IN INTEGRATED CIRCUIT MANUFACTURE ARE CORRECTED DURING THE DEVELOPMENT PROCESS. A SILVER HALIDE EMULSION IS EXPOSED TO FROM A LATENT IMAGE OF A CIRCIUT PATTERN. THE EMULSION IS PARTIALLY DEVELOPED AND IS THEN OBSERVED UNDER A MICROSCOPE USING RED SAFE-LIGHT ILLUMINATION. THE AREAS WHICH SHOULD HAVE BEEN EXPOSED BUT WHERE NOT; DUE, FOR EXAMPLE, TO THE PRESENCE OF DIRT PARTICLES, ARE VISUALLY LOCATED AS SHOWING RED AGAINST A BLACK OR GRAY BACKGROUND. THESE AREAS ARE THEN SELECTIVELY EXPOSED, AND THE DEVELOPMENT OF THE EMULSION IS COMPLETED.
Inventors
- 👤 J Zingerman
- 👤 Fazio J Di
- 👤 G Giuffre
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 23:40
CPC Classifications
G; G03; G03F; G03F1/00; G03F1/54; G03F1/68; G03F1/72
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 |