US4988404A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of producing a primary diffraction grating
Assignee: Mitsubishi Electric Corp
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Filing: 1989-10-16
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Granted: 1991-01-29
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Expires: 2009-10-16
Abstract
Abstract A method of producing a primary diffraction grating includes depositing a resist pattern for producing a secondary diffraction grating on a substrate and thereafter etching the substrate using the resist as a mask, thereby producing a secondary diffraction grating, depositing a second mask material on the substrate and on the remaining resist, and subsequently removing the resist, and etching the exposed surface of the substrate using the second mask material as a mask, thereby to produce a primary diffraction grating. Therefore, there arises no waviness in the pattern end of the second resist mask pattern and a high quality primary diffraction grating can be produced.
Inventors
- 👤 Toshitaka Aoyagi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 12:39
CPC Classifications
G; G02; G02B; G02B5/00; G02B5/18; G02B5/1847; G02B5/1857; C; C03; C03C; C03C15/00
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
91 words
A method of producing a primary diffraction grating comprising: forming a resist pattern for producing a second diffraction grating on a substrate; etching said substrate using said resist pattern as a mask, thereby producing a secondary diffraction grating; depositing a second mask material on said substrate and on the resist remaining on said substrate; removing said resist and the second mask material that overlies said resist; and etching the exposed surface of said substrate using said second mask material on said substrate as a mask, thereby producing a primary diffraction grating.
Claim 2
Independent Claim
91 words
A method of producing a primary diffraction grating comprising: forming a resist pattern for producing a second diffraction grating on a substrate; etching said substrate using said resist pattern as a mask, thereby producing a secondary diffraction grating; depositing a second mask material on said substrate and on the resist remaining on said substrate; removing said resist and the second mask material that overlies said resist; and etching the exposed surface of said substrate using said second mask material on said substrate as a mask, thereby producing a primary diffraction grating.
Claim 3
Dependent Claim
21 words
A method of producing a primary diffraction grating as defined in claim 1 wherein said second mask material comprises silicon nitride.
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) | 1994-01-28 | 1994-07-30 | 1995-01-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-01-28 | 1998-07-30 | 1999-01-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-01-28 | 2002-07-30 | 2003-01-29 | $7700.00 | Window Closed / Lapsed |