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US4764432A
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Photo-mask with regions having a differing optical transmissivities
Assignee: Max-Planck-Gesellschaft zur Förderung der Wissenschaften eV
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Filing: 1986-07-01
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Granted: 1988-08-16
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Expires: 2006-07-01
Abstract
Abstract A photomask useful as stencil or reticle comprises a thin layer, which includes regions of different optical transmissivity for light radiation of a predetermined spectral range. The layer consists of silicon or any other suitable semiconductor material, and the regions of different transmissivity consist essentially of the monocrystalline or amorphous phase of the mask material. The photomask may be manufactured by irradiating a thin layer of monocrystalline silicon with a focussed ion beam to convert the silicon within the irradiated regions into the amorphous phase.
Inventors
- 👤 Siegfried Kalbitzer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 00:27
CPC Classifications
G; G03; G03F; G03F1/00; G03F1/68; G03F1/76; G03F1/78; G03F1/50; G03F1/54; Y; Y10; Y10T; Y10T428/00; Y10T428/24; Y10T428/24802; Y10T428/24926; Y10T428/24942
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
148 words
A photomask including a layer which comprises regions (16, 18) of different optical transmissivity for optical radiation within a predetermined spectral range, on a substrate (12) which is transparent to the optical radiation with which the photomask is used, characterized in that said layer comprises a semiconductor material which has a crystalline and an amorphous phase, said crytalline phase having a substantially greater optical transmissivity in said predetermined spectral range than said amorphous phase has, said regions each extend far enough through the thickness of said layer that portions (18) of said layer containing more amorphous phase material have absorption coefficients, for optical radiation within said predetermined spectral range, at least a factor of 2 greater than the absorption coefficients of other portions (16) of said layer predominantly containing crystalline material, and that said regions comprise different proportions of said crystalline and amorphous phases of said semiconductor material.
Claim 2
Dependent Claim
148 words
A photomask including a layer which comprises regions (16, 18) of different optical transmissivity for optical radiation within a predetermined spectral range, on a substrate (12) which is transparent to the optical radiation with which the photomask is used, characterized in that said layer comprises a semiconductor material which has a crystalline and an amorphous phase, said crytalline phase having a substantially greater optical transmissivity in said predetermined spectral range than said amorphous phase has, said regions each extend far enough through the thickness of said layer that portions (18) of said layer containing more amorphous phase material have absorption coefficients, for optical radiation within said predetermined spectral range, at least a factor of 2 greater than the absorption coefficients of other portions (16) of said layer predominantly containing crystalline material, and that said regions comprise different proportions of said crystalline and amorphous phases of said semiconductor material.
Claim 3
Dependent Claim
24 words
A photomask as claimed in claim 1 wherein said semiconductor material is silicon and said regions comprise different proportions of crystalline and amorphous silicon.
Claim 4
Dependent Claim
20 words
The photomask as claimed in claim 2, wherein the thickness of said layer is in the order of 0.1 micrometers.
Claim 5
Dependent Claim
19 words
The photomask as claimed in claim 2 wherein said silicon layer is supported by a substrate made of sapphire.
Claim 6
Dependent Claim
19 words
The photomask as claimed in claim 2 characterized in that some of said regions consist essentially of crystalline silicon.
Claim 7
Dependent Claim
17 words
The photomask as claimed in claim 2, wherein some of said regions consist essentially of monocrystalline silicon.
Claim 8
Dependent Claim
18 words
The photomask as claimed in claim 2, wherein said mask comprises regions which consist essentially of amorphous silicon.
Claim 9
Dependent Claim
46 words
A photomask as claimed in claim 1, wherein the thickness of said layer is selected such that the optical transmissivity of one (16) of said regions is about one half, and the optical transmissivity of the other (18) of said regions is substantially less than half.
Claim 10
Dependent Claim
27 words
The photomask of claim 8, wherein the respective optical transmissivities of said regions are selected such that a contrast ratio between said regions of about 0.85 results.
References Cited (Backward Citations)
GB1217169A
Cited
US4315782A
Cited
US4339285A
Cited
US4388400A
Cited
JPS57157248A
Cited
US4498224A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-08-16 | 1992-02-15 | 1992-08-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-08-16 | 1996-02-15 | 1996-08-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-08-16 | 2000-02-15 | 2000-08-16 | $7700.00 | Window Closed / Lapsed |