US5851702A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for producing a photomask
Assignee: Sharp Corp
•
Filing: 1997-06-10
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Granted: 1998-12-22
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Expires: 2017-06-10
Abstract
Abstract A method for producing a photomask of the present invention includes the steps of: forming a light-blocking film on a surface of a transparent substrate; forming a resist film for an EB on the light-blocking film; patterning the resist film by EB writing and development; and selectively etching the light-blocking film using the patterned resist film to form a photomask, wherein the light-blocking film has a thickness in the range of about 60 nm to about 70 nm.
Inventors
- 👤 Kunio Watanabe
- 👤 Shinji Kobayashi
- 👤 Masashi Inoue
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 07:53
CPC Classifications
G; G03; G03F; G03F7/00; G03F1/00; G03F1/54; G03F1/50
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
85 words
A method for producing a photomask, comprising the steps of: forming a light-blocking film on a surface of a transparent substrate; forming a resist film for an EB on the light-blocking film on a side thereof remote from the substrate; patterning the resist film by EB writing and development; and selectively etching the light-blocking film using the patterned resist film as a mask to form a photomask; wherein the light-blocking film has a thickness in the range of about 60 nm to about 70 nm.
Claim 2
Independent Claim
85 words
A method for producing a photomask, comprising the steps of: forming a light-blocking film on a surface of a transparent substrate; forming a resist film for an EB on the light-blocking film on a side thereof remote from the substrate; patterning the resist film by EB writing and development; and selectively etching the light-blocking film using the patterned resist film as a mask to form a photomask; wherein the light-blocking film has a thickness in the range of about 60 nm to about 70 nm.
Claim 3
Dependent Claim
28 words
A method for producing a photomask according to claim 1, wherein the resist film has a thickness in the range of about 280 nm to about 350 nm.
Claim 4
Dependent Claim
24 words
A method for producing a photomask according to claim 2, wherein the step of selectively etching the light-blocking film is performed by dry etching.
Claim 5
Dependent Claim
16 words
A method for producing a photomask according to claim 3, wherein the light-blocking film contains chromium.
Claim 6
Dependent Claim
16 words
A method for producing a photomask according to claim 1, wherein the light-blocking film contains chromium.
Claim 7
Dependent Claim
37 words
A method for producing a photomask according to claim 1, wherein an exposure amount of an EB used in the EB writing is in the range of about 2.3 μC/cm 2 to about 2.6 μC/cm 2 .
Claim 8
Dependent Claim
24 words
A method for producing a photomask according to claim 1, wherein the step of selectively etching the light-blocking film is performed by dry etching.
References Cited (Backward Citations)
JPH05175094A
Cited
US5658826A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2001-12-21 | 2002-06-22 | 2002-12-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-12-21 | 2006-06-22 | 2006-12-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-12-21 | 2010-06-22 | 2010-12-22 | $7700.00 | Window Closed / Lapsed |