US3718503A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of forming a diffusion mask barrier on a silicon substrate
Assignee: United States Department of the Army
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Filing: 1971-07-14
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Granted: 1973-02-27
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Expires: 1991-07-14
Abstract
Abstract THE TOP SURFACE OF A SILICON SUBSTRATE HAVING A PARTICULAR IMPURITY PROFILE IS EXPOSED TO A CHEMICAL VAPOR ENVIRONMENT OF NITRIC OXIDE, HYDROGEN FLUORIDE AND WATER AT ABOUT 35 DEGREES C., AND FOR ABOUT 3 TO 5 MINUTES SIMULTANEOUSLY WITH THE EXPOSURE TO THE ABOVE-DESCRIBED VAPOR MIXTURE AN IMAGE IS PROJECTED INTO THE TOP SURFACE OF THE SILICON SUBSTRATE DURING THE ENTIRE TIME INTERVAL OF VAPOR EXPOSURE. FOR COMPLETION OF DEVICE FABRICATION, DOPANT ATOMS ARE THEN DIFFUSIONN INTO THE SILICON SURFACE WHERE THE IMAGE HAS BEEN PROJECTED.
Inventors
- 👤 W Glendinning
- 👤 W Pharo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 05:06
CPC Classifications
H; H10; H10P; H10P76/00; H10P76/40; H10P76/405; H10P14/00; H10P14/60; H10P14/63; H10P14/6302; H10P14/6304; H10P14/6306; H10P50/00; H10P50/20; H10P50/24; H10P50/242; H10P95/00; Y; Y10; Y10S; Y10S148/00; Y10S148/051; Y10S148/106; Y10S438/00; Y10S438/911
Claims Analysis
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References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-02-27 | 1976-08-28 | 1977-02-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-02-27 | 1980-08-28 | 1981-02-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-02-27 | 1984-08-28 | 1985-02-27 | $7700.00 | Window Closed / Lapsed |