US3811973A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Technique for the fabrication of a bilevel thin film integrated circuit
Assignee: AT&T Inc
•
Filing: 1972-08-11
•
Granted: 1974-05-21
•
Expires: 1992-08-11
Abstract
Abstract BELIEVEL THIN FILM CIRCUITS HAVING GOLD METALLIZED THROUGH HOLES REQUIRE PROTECTION FROM ATTACK BY GOLD CONDUCTOR ETCHANTS. A NOVEL PROCEDURE FOR EFFECTING THIS END INVOLVES PLATING AN ETCH STOP SUCH AS RHODIUM OR PLATINUM UPON THE WALLS OF THE THROUGH HOLES AND AROUND THE ENTRANCE AND EXIT PORTS. SINCE RHODIUM PLATING IS NORMALLY REQUIRED IN THE FABRICATION OF SUCH CIRCUITS FOR SOLDERABLE COMPONENTS, THE THROUGH HOLE PROTECTION AND RHODIUM PLATING MAY NE PERFORMED SIMULTANEOUSLY.
Inventors
- 👤 B Unger
- 👤 N Lesh
- 👤 Day P O
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 07:50
CPC Classifications
H; H05; H05K; H05K3/00; H05K3/02; H05K3/06; H05K3/061; H05K3/062; H05K1/00; H05K1/02; H05K1/09; H05K3/0094; H05K1/03; H05K1/0306; H05K2201/00; H05K2201/03; H05K2201/0332; H05K2201/0335; H05K2201/0338; H05K3/064; H05K3/22; H05K3/24; H05K3/243; H05K3/38; H05K3/388; H05K3/40; H05K3/42; H05K3/425; H05K3/426
Claims Analysis
Total Claims: 0
No claims parsed yet. Click Sync Now above to re-index claims from Google Patents.
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) | 1977-05-20 | 1977-11-19 | 1978-05-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-05-20 | 1981-11-19 | 1982-05-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-05-20 | 1985-11-19 | 1986-05-21 | $7700.00 | Window Closed / Lapsed |