US4902899A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Lithographic process having improved image quality
Assignee: International Business Machines Corp
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Filing: 1987-06-01
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Granted: 1990-02-20
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Expires: 2007-06-01
Abstract
Abstract A lithographic process having improved image quality by employing a mask that includes a plurality of opaque elements or transparent elements that are smaller than the resolution of the lighography to be employed in order to control the transmittance of the actinic light exposure area.
Inventors
- 👤 Burn J. Lin
- 👤 Anne M. Moruzzi
- 👤 Alan E. Rosenbluth
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 17:54
CPC Classifications
G; G03; G03F; G03F7/00; G03F7/70; G03F7/70058; G03F1/00; G03F1/50; G03F7/20; G03F7/2002; G03F7/70216; G03F7/70283; G03F7/70425; G03F7/70433
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
107 words
A lithographic process having improved image quality that comprises: positioning a member including a photosensitive layer at the imaging plane of a projection lens with respect to a lithographic mask that defines areas that are to receive actinic light wherein said lithographic mask includes a plurality of opaque elements or transparent elements, each of which is smaller than the resolution of the projection lens, to be employed for controlling the transmittance of the actinic light defining area, and wherein the concentrations of said elements are varied within an individual mask opening to provide higher transmission in the corners and along the edges of said individual mask opening.
Claim 2
Dependent Claim
107 words
A lithographic process having improved image quality that comprises: positioning a member including a photosensitive layer at the imaging plane of a projection lens with respect to a lithographic mask that defines areas that are to receive actinic light wherein said lithographic mask includes a plurality of opaque elements or transparent elements, each of which is smaller than the resolution of the projection lens, to be employed for controlling the transmittance of the actinic light defining area, and wherein the concentrations of said elements are varied within an individual mask opening to provide higher transmission in the corners and along the edges of said individual mask opening.
Claim 3
Dependent Claim
15 words
The lithographic process of claim 1 wherein said mask includes a plurality of opaque elements.
Claim 4
Dependent Claim
24 words
The lithographic process of claim 1 wherein said elements include half-tones, semi-transparent half-tones, or phase shifting regions or a combination of any of them.
Claim 5
Dependent Claim
101 words
A lithographic proximity printing process having improved image quality that comprises: positioning a member including a photosensitive layer in proximity to a lithographic mask that defines areas that are to receive actinic light wherein said lithographic mask includes a plurality of opaque elements or transparent elements, each of which is smaller than the resolution of the proximity printing, to be employed for controlling the transmittance of the actinic light defining area, and wherein the concentrations of said elements are varied within an individual mask opening to provide higher transmission in the corners and along the edges of said individual mask opening.
Claim 6
Dependent Claim
101 words
A lithographic proximity printing process having improved image quality that comprises: positioning a member including a photosensitive layer in proximity to a lithographic mask that defines areas that are to receive actinic light wherein said lithographic mask includes a plurality of opaque elements or transparent elements, each of which is smaller than the resolution of the proximity printing, to be employed for controlling the transmittance of the actinic light defining area, and wherein the concentrations of said elements are varied within an individual mask opening to provide higher transmission in the corners and along the edges of said individual mask opening.
Claim 7
Dependent Claim
15 words
The lithographic process of claim 4 wherein said mask includes a plurality of opaque elements.
Claim 8
Dependent Claim
24 words
The lithographic process of claim 4 wherein said elements include half-tones, semi-transparent half-tones, or phase shifting regions or a combination or any of them.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-02-19 | 1993-08-21 | 1994-02-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-02-19 | 1997-08-21 | 1998-02-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-02-19 | 2001-08-21 | 2002-02-20 | $7700.00 | Window Closed / Lapsed |