Method of making chromium mask for photoresist application
Abstract
Abstract A DURABLE AND ADHERENT FILM OF CHROMIUM OF ABOUT 2000 TO ABOUT 4500 ANGSTROMS IN THICKNESS IS FIRST VACUUM DEPOSITED ONTO A GLASS SUBSTRATE. A DURABLE CHROMIUM MASK SUITABLE FOR PHOTORESIST APPLICATIONS IS THEN MADE BY COATING THE CHROMIUM FILM WITH PHOTORESIST, AIR DRYING THE PHOTORESIST COVERED CHROMIUM FILM AND THEN PREBAKING THE COVERED FILM AT 100 TO 120 DEGREES C. FOR AT LEAST 15 MINUTES, PLACING A PHOTOGRAPHIC TRANSPARENCY HAVING THE DESIRED PATTERN OVER THE PHOTORESIST FILM, EXPOSING THE FILM TO ULTRAVIOLET LIGHT, DEVELOPING AND THEN FINALLY BAKING THE PHOTORESIST AT 100 TO 120 DEGREES C. FOR 5 TO 15 MINUTES, ETCHING THE CHROMIUM FILM IN THE AREAS VOID OF PHOTORESIST IN A SOLUTION OF ABOUT 1 TO 3 GRAMS OF ZINC METAL IN ABOUT 20 TO 50 CC. OF CONCENTRATED HYDROCHLORIC ACID, AND HEATING THE FILM TO ABOUT 400 DEGREES C. AFTER PATTERN ETCHING.
Inventors
- 👤 Armand P La Rocque
- 👤 Alex Rogel
Bibliographic Details
Claims Analysis
Total Claims: 0References 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) | 1974-08-16 | 1975-02-15 | 1975-08-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-08-16 | 1979-02-15 | 1979-08-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-08-16 | 1983-02-15 | 1983-08-17 | $7700.00 | Window Closed / Lapsed |