US4253029A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Mask structure for x-ray lithography
Assignee: AT&T Inc
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Filing: 1979-05-23
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Granted: 1981-02-24
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Expires: 1999-05-23
Abstract
Abstract A mask substrate for use in an x-ray lithographic system comprises a boron nitride member (32, FIG. 2) coated with a polyimide layer (20) whose thickness is approximately the same as that of the boron nitride member. The substrate is mechanically strong and both optically and x-ray transparent. Mask patterns formed on the substrate are characterized by low distortion and a low defect density.
Inventors
- 👤 Martin P. Lepselter
- 👤 Hyman J. Levinstein
- 👤 Dan Maydan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 15:13
CPC Classifications
G; G03; G03F; G03F1/00; G03F1/22; Y; Y10; Y10S; Y10S430/00; Y10S430/167
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
77 words
A mask structure for x-ray lithography comprising a support member, an x-ray-transparent member bonded to said support member, said x-ray-transparent member being made of a material selected from the group consisting of boron nitride, boron carbide and silicon carbide, and an x-ray-transparent organic layer deposited on said x-ray-transparent member to form therewith a tensile composite substrate for supporting an x-ray-absorptive pattern in a low-distortion low-defect-density way, said x-ray-transparent member and layer each having approximately the same thickness.
Claim 2
Dependent Claim
77 words
A mask structure for x-ray lithography comprising a support member, an x-ray-transparent member bonded to said support member, said x-ray-transparent member being made of a material selected from the group consisting of boron nitride, boron carbide and silicon carbide, and an x-ray-transparent organic layer deposited on said x-ray-transparent member to form therewith a tensile composite substrate for supporting an x-ray-absorptive pattern in a low-distortion low-defect-density way, said x-ray-transparent member and layer each having approximately the same thickness.
Claim 3
Dependent Claim
21 words
A mask structure as in claim 1 wherein said layer is made of a polyimide material exhibiting an inplane tensile stress.
Claim 4
Dependent Claim
26 words
A mask structure as in claim 2 wherein said x-ray-transparent member comprises a boron nitride layer which has been silicon-doped to provide a layer in tension.
Claim 5
Dependent Claim
31 words
A mask structure as in claim 3 wherein said x-ray-transparent member comprises said silicon-doped boron nitride layer in tension interposed between two relatively thin undoped boron nitride layers each in compression.
Claim 6
Dependent Claim
15 words
A mask structure as in claim 4 wherein said support member comprises a silicon ring.
Claim 7
Dependent Claim
21 words
A mask structure as in claim 5 wherein said support member further comprises a Pyrex ring bonded to said silicon ring.
Claim 8
Dependent Claim
41 words
A mask structure as in claim 6 wherein an x-ray-absorptive pattern comprising three-layer elements each made of a layer of gold sandwiched between layers of tantalum is formed on and adhered to the top surface of said layer of polyimide material.
Claim 9
Dependent Claim
27 words
A mask structure as in claim 7 further including an x-ray-transparent protective layer deposited on the top surfaces of said elements and said layer of polyimide material.
Claim 10
Dependent Claim
51 words
A mask structure as in claim 8 wherein the thickness of said boron nitride member is approximately 6 micrometers, the thickness of said polyimide material is approximately 5.5 L micrometers, each of said x-ray-absorptive elements is approximately 0.73 micrometers thick, and the thickness of said protective layer is approximately one micrometer.
Claim 11
Dependent Claim
50 words
In combination in a mask structure, a boron nitride member bonded to a support frame, and an optically- and x-ray-transparent layer of an organic material bonded to said member, said layer of organic material having approximately the same thickness as said member and forming therewith a composite structure in tension.
Claim 12
Dependent Claim
50 words
In combination in a mask structure, a boron nitride member bonded to a support frame, and an optically- and x-ray-transparent layer of an organic material bonded to said member, said layer of organic material having approximately the same thickness as said member and forming therewith a composite structure in tension.
Claim 13
Dependent Claim
51 words
An x-ray-transparent mask structure comprising a lamination of a boron nitride member and a polyimide layer, said member and layer each having approximately the same thickness and the top surface of said layer being characterized by an in-plane tensile stress, and wherein said member is peripherally bonded to a support element.
Claim 14
Dependent Claim
51 words
An x-ray-transparent mask structure comprising a lamination of a boron nitride member and a polyimide layer, said member and layer each having approximately the same thickness and the top surface of said layer being characterized by an in-plane tensile stress, and wherein said member is peripherally bonded to a support element.
Claim 15
Dependent Claim
43 words
An x-ray lithographic process for fabricating high-resolution devices by illuminating in its entirety a patterned mask structure that comprises a lamination of a boron nitride member and an approximately equal-thickness polyimide layer to selectively irradiate an associated wafer coated with an x-ray-sensitive material.
Claim 16
Dependent Claim
43 words
An x-ray lithographic process for fabricating high-resolution devices by illuminating in its entirety a patterned mask structure that comprises a lamination of a boron nitride member and an approximately equal-thickness polyimide layer to selectively irradiate an associated wafer coated with an x-ray-sensitive material.
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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) | 1984-02-24 | 1984-08-25 | 1985-02-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-02-24 | 1988-08-25 | 1989-02-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-02-24 | 1992-08-25 | 1993-02-24 | $7700.00 | Window Closed / Lapsed |