US4522842A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Boron nitride X-ray masks with controlled stress
Assignee: Nokia Bell Labs
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Filing: 1982-09-09
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Granted: 1985-06-11
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Expires: 2002-09-09
Abstract
Abstract It has been found that stress in X-ray transparent films used to form masks for X-ray lithography also cause distortions of the film and of the high-resolution X-ray-absorptive pattern formed thereon. A method is disclosed which anneals boron nitride films for use in X-ray masks in such a way as to control stress.
Inventors
- 👤 Hyman J. Levinstein
- 👤 Shyam P. Murarka
- 👤 David S. Williams
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 19:39
CPC Classifications
G; G03; G03F; G03F1/00; G03F1/22; C; C23; C23C; C23C16/00; C23C16/56
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
73 words
A process for fabricating a mask structure for X-ray lithography, comprising the steps of depositing on a support member a layer of an X-ray transparent material, determining the stress of the layer, annealing said layer subsequent to said deposition to obtain therein a stress in a desired range, said annealing step controlling the stress subsequent to said deposition, whereby the film is made more tensile or more compressive depending on what is desired.
Claim 2
Dependent Claim
73 words
A process for fabricating a mask structure for X-ray lithography, comprising the steps of depositing on a support member a layer of an X-ray transparent material, determining the stress of the layer, annealing said layer subsequent to said deposition to obtain therein a stress in a desired range, said annealing step controlling the stress subsequent to said deposition, whereby the film is made more tensile or more compressive depending on what is desired.
Claim 3
Dependent Claim
26 words
A process as recited in claim 1 wherein said layer of X-ray transparent material is selected from the group consisting of boron nitride and boron carbide.
Claim 4
Dependent Claim
14 words
A process as recited in claim 2 in which said material comprises boron nitride.
Claim 5
Dependent Claim
27 words
A process as recited in claim 2 or 3 comprising the further step of forming a patterned layer of X-ray absorbing material on said X-ray transparent material.
Claim 6
Dependent Claim
15 words
A process as recited in claim 4 wherein said deposition step comprises a LPCVD process.
Claim 7
Dependent Claim
22 words
A process as recited in claim 5 wherein said deposition step is carried out at a temperature less than 700 degrees C.
Claim 8
Dependent Claim
15 words
The process of claim 5 wherein said determining the stress is by measuring each wafer.
Claim 9
Dependent Claim
16 words
A process as in claim 5 wherein the annealing step is in an atmosphere comprising hydrogen.
Claim 10
Dependent Claim
20 words
A process as recited in claim 8 in which said annealing is at a temperature of approximately 340 degrees C.
Claim 11
Dependent Claim
18 words
A process as in claim 5 wherein said annealing step is in an atmosphere at a reduced pressure.
Claim 12
Dependent Claim
27 words
A process as recited in claim 10 in which said atmosphere comprises an inert gas selected from the group consisting of nitrogen, argon, helium, xenon, neon, krypton.
Claim 13
Dependent Claim
20 words
A process as recited in claim 11 in which said annealing is at a temperature less than 440 degrees C.
Claim 14
Dependent Claim
20 words
A process as recited in claim 12 in which said annealing is at a temperature greater than 360 degrees C.
Claim 15
Dependent Claim
14 words
A process as recited in claim 12 in which said inert gas is nitrogen.
Claim 16
Dependent Claim
14 words
A process as recited in claim 12 in which said inert gas is argon.
Claim 17
Dependent Claim
14 words
A process as recited in claim 12 in which said inert gas is helium.
Claim 18
Dependent Claim
14 words
A process as recited in claim 12 in which said inert gas is xenon.
Claim 19
Dependent Claim
14 words
A process as recited in claim 12 in which said inert gas is neon.
Claim 20
Dependent Claim
14 words
A process as recited in claim 12 in which said inert gas is krypton.
Claim 21
Dependent Claim
62 words
A process as recited in claim 5 in which said depositing step comprises: flowing ammonia (NH 3 ) and diborane (B 2 H 6 ), with nitrogen as the carrier gas, and said annealing step is within the range 500 degrees C.±200 degrees C. thereby yielding a film in a desired stress range of about 0.1 to 0.5×10 9 dynes/cm 2 .
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-06-10 | 1988-12-10 | 1989-06-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-06-10 | 1992-12-10 | 1993-06-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-06-10 | 1996-12-10 | 1997-06-11 | $7700.00 | Window Closed / Lapsed |