Patent US1554370A successfully refreshed from Google Patents.
Patent US3592773A successfully refreshed from Google Patents.
US3592773A
Expired / Lapsed
US
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Solvent mixture with nitric acid and hydrofluoric acid for wet chemical etching of silicon
Assignee: Siemens AG
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Filing: 1968-03-25
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Granted: 1971-07-13
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Expires: 1988-03-25
Abstract
Abstract DESCRIBED IS A SOLVENT MIXTURE OF NITRIC ACID AND HYDROFLUORIC ACID FOR WET CHEMICAL ETCHING OF SILICON OBJECTS. THE SOLVENT MIXTURE IS CHARACTERIZED BY THE INCORPORATION OF AT LEAST ONE ADDITION TO THE MIXTURE. THIS ADDITION REACTS WITH NITROUS ACID AND WITH NITROGEN OXIDES PRESENT THROUGH THE CHEMICAL EQUILIBRIUM OF NITROUS ACID WITH NITROGEN OXIDE. THE ADDITIONS ARE PRIMARY OR SECONDARY ALIPHATIC OR AROMATIC AMINES, SIMPLE AND N-SUBSTITUTED ACID AMIDES, HYDRAZINE AND HYDROXYLAMJINE, THEIR DERIVATIVES AND SALTS AND S-N COMPOUNDS WHICH CONTAIN=NH OR -NH2 GROUPS. ILLUSTRATORY ADDITIONS ARE CARBAMIDE, CYCLOHEXYLAMINE, GELATINE AND HYDRAZINE.
Inventors
- 👤 Alfred Muller
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 23:38
CPC Classifications
C; C09; C09K; C09K13/00; C09K13/04; C09K13/08; Y; Y10; Y10S; Y10S148/00; Y10S148/051; Y10S148/054
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) | 1974-07-12 | 1975-01-11 | 1975-07-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-07-12 | 1979-01-11 | 1979-07-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-07-12 | 1983-01-11 | 1983-07-13 | $7700.00 | Window Closed / Lapsed |