US4405701A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Methods of fabricating a photomask
Assignee: AT&T Inc
•
Filing: 1982-09-17
•
Granted: 1983-09-20
•
Expires: 2002-09-17
Abstract
Abstract A photomask (30) used to form patterns on a resist coated semiconductor wafer is comprised of a transparent baseplate (31) having a thin metallic pattern (32) thereon; a transparent, planar coverplate (33) in intimate contact with the patterned baseplate (31) and an index matching fluid (34) interposed therebetween.
Inventors
- 👤 Edward L. Banks
- 👤 Bruce E. Truax
- 👤 Laurence S. Watkins
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 16:58
CPC Classifications
G; G03; G03F; G03F1/00; G03F1/38; G03F1/48; Y; Y10; Y10T; Y10T428/00; Y10T428/24; Y10T428/24802; Y10T428/24851; Y10T428/24868; Y10T428/24917; Y10T428/24926
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
88 words
A method of fabricating a photomask, comprising the steps of: placing a substantially flat, light transmissive coverplate in intimate contact with a light transmissive baseplate having a metallic pattern thereon; depositing at least one drop of, a refractive index matching fluid at the interface edge of the coverplate and baseplate, said fluid having substantially the same refractive index as said baseplate and said coverplate; and heating the baseplate, coverplate and the refractive index matching fluid to cause the fluid to flow between the patterned baseplate and the coverplate.
Claim 2
Independent Claim
88 words
A method of fabricating a photomask, comprising the steps of: placing a substantially flat, light transmissive coverplate in intimate contact with a light transmissive baseplate having a metallic pattern thereon; depositing at least one drop of, a refractive index matching fluid at the interface edge of the coverplate and baseplate, said fluid having substantially the same refractive index as said baseplate and said coverplate; and heating the baseplate, coverplate and the refractive index matching fluid to cause the fluid to flow between the patterned baseplate and the coverplate.
Claim 3
Dependent Claim
26 words
The method as set forth in claim 1, wherein: the baseplate and coverplate are heated within a temperature range of approximately 70° C. to 100° C.
References Cited (Backward Citations)
US1985074A
Cited
US2175343A
Cited
US2317550A
Cited
US3193840A
Cited
US3400995A
Cited
US3906133A
Cited
US4201581A
Cited
US4256787A
Cited
JPS56130749A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-09-19 | 1987-03-21 | 1987-09-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-09-19 | 1991-03-21 | 1991-09-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-09-19 | 1995-03-21 | 1995-09-20 | $7700.00 | Window Closed / Lapsed |