US4248948A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Photomask
Assignee: Toshiba Corp
•
Filing: 1977-03-28
•
Granted: 1981-02-03
•
Expires: 1997-03-28
Abstract
Abstract A photomask comprising a substrate pervious to light having one or more transparent islands and one or more opaque islands formed on one surface thereof, the thickness of the transparent islands being greater than that of the opaque islands. When this photomask is used to pattern a photoresist, the gas evolved from the photoresist can be effectively led to the outside, so that the quality of contact between the semiconductor wafer and the photomask is improved.
Inventors
- 👤 Takashi Matsuda
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 04:10
CPC Classifications
G; G03; G03F; G03F1/00; G03F1/50; Y; Y10; Y10S; Y10S438/00; Y10S438/942; Y10T; Y10T428/00; Y10T428/24; Y10T428/24802; Y10T428/24917; Y10T428/24926
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
130 words
A photomask to pattern a photoresist of a semi-conductor during fabrication of a semiconductor device, said photomask being placed to face said photoresist and being exposed to light, said photomask comprising a substrate pervious to light and means for elimination of gas generated during said exposure to light, said means including one or more transparent islands formed on and projecting from one surface of the substrate, and one or more opaque islands formed on and projecting from the same surface of the substrate spaced from the transparent islands, the thickness of said transparent islands being greater than that of said opaque islands, said transparent islands being formed of silicate glass, silicon dioxide, phosphosilicate glass, or trisilicon tetranitride, and said opaque islands being formed of a metal or a metal oxide.
Claim 2
Dependent Claim
130 words
A photomask to pattern a photoresist of a semi-conductor during fabrication of a semiconductor device, said photomask being placed to face said photoresist and being exposed to light, said photomask comprising a substrate pervious to light and means for elimination of gas generated during said exposure to light, said means including one or more transparent islands formed on and projecting from one surface of the substrate, and one or more opaque islands formed on and projecting from the same surface of the substrate spaced from the transparent islands, the thickness of said transparent islands being greater than that of said opaque islands, said transparent islands being formed of silicate glass, silicon dioxide, phosphosilicate glass, or trisilicon tetranitride, and said opaque islands being formed of a metal or a metal oxide.
Claim 3
Dependent Claim
30 words
A photomask as claimed in claim 1 wherein said metal is chromium and said metallic oxide is one kind selected from the group consisting of iron oxide and chromium oxide.
Claim 4
Dependent Claim
21 words
A photomask as claimed in claim 1 wherein the thickness of said transparent islands is from about 0.1μ to about 2.0μ.
Claim 5
Dependent Claim
21 words
A photomask as claimed in claim 1 wherein the thickness of said opaque islands is from about 0.06μ to about 0.3μ.
Claim 6
Dependent Claim
18 words
A photomask as claimed in claim 1 wherein said substrate pervious to light is made of silicate glass.
References Cited (Backward Citations)
US3118788A
Cited
US3758326A
Cited
US3753816A
Cited
US3866310A
Cited
US4113486A
Cited
US3991231A
Cited
US3926699A
Cited
US4068018A
Cited
US3990982A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-02-03 | 1984-08-04 | 1985-02-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-02-03 | 1988-08-04 | 1989-02-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-02-03 | 1992-08-04 | 1993-02-03 | $7700.00 | Window Closed / Lapsed |