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US4530891A
Expired / Lapsed
US
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Photo-mask blank for use in lithography including a modified chromium compound
Assignee: Hoya Corp
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Filing: 1983-12-29
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Granted: 1985-07-23
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Expires: 2003-12-29
Abstract
Abstract In a photo-mask blank, a transparent substrate is covered with a shading layer including chromium and chromium carbide. On the shading layer is an antireflection layer which includes chromium and chromium nitride. The shading and the antireflection layers are deposited in the same hollow space by sputtering. The etch rate of the shading layer is adjustable to that of the antireflection layer to make both etch rates equal and, thereby, to reduce undercuts appearing at the shading layer.
Inventors
- 👤 Osamu Nagarekawa
- 👤 Shigekazu Matsui
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 16:21
CPC Classifications
G; G03; G03F; G03F1/00; G03F1/54; G03F1/58; G03F1/38; G03F1/46; Y; Y10; Y10T; Y10T428/00; Y10T428/24; Y10T428/24802; Y10T428/24851; Y10T428/24868
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
77 words
A photo-mask blank for use in lithography comprising a substrate transparent to light in a predetermined wavelength region and having a principal surface, a shading layer on said principal surface which includes chromium and chromium carbide for shading the light in said predetermined wavelength region, and an antireflection layer overlaid on said shading layer which includes chromium oxide and chromium nitride for reducing reflection of the light in at least a part of said predetermined wavelength region.
Claim 2
Dependent Claim
77 words
A photo-mask blank for use in lithography comprising a substrate transparent to light in a predetermined wavelength region and having a principal surface, a shading layer on said principal surface which includes chromium and chromium carbide for shading the light in said predetermined wavelength region, and an antireflection layer overlaid on said shading layer which includes chromium oxide and chromium nitride for reducing reflection of the light in at least a part of said predetermined wavelength region.
Claim 3
Dependent Claim
21 words
A photo-mask blank as claimed in claim 1 wherein said shading layer and said antireflection layer have substantially equal etch rates.
Claim 4
Dependent Claim
30 words
A photo-mask blank as claimed in claim 1 constituted as a composite consisting of said substrate with said shading layer and said antireflection layer applied thereto as a two-layer covering.
Claim 5
Dependent Claim
32 words
A photo-mask blank as claimed in claim 1 wherein said shading layer consists essentially of said chromium and chromium carbide and said anti-reflection layer consists essentially of chromium oxide and chromium nitride.
Claim 6
Dependent Claim
29 words
A photo-mask blank as claimed in claim 4 wherein said shading layer is sputter deposited on said substrate and said anti-reflection layer is sputter deposited on said shading layer.
Claim 7
Dependent Claim
38 words
A photo-mask blank as claimed in claim 1, said blank having a relatively flat characteristic of reflection index (%) vs wavelength (nm) in the region of 350-600 nm in which the reflection index is between 11 and 20%.
Claim 8
Dependent Claim
24 words
A photo-mask blank as claimed in claim 6 wherein the reflection index has a minimum value at a wavelength between 400 and 500 nm.
Claim 9
Dependent Claim
26 words
A photo-mask blank as claimed in claim 1 wherein the chromium and chromium carbide of the shading layer coexist in the form of interstitial chromium carbide.
Claim 10
Dependent Claim
13 words
A photo-mask blank as claimed in claim 1, wherein said substrate is glass.
Claim 11
Dependent Claim
13 words
A photo-mask blank as claimed in claim 1, wherein said substrate is quartz.
Claim 12
Dependent Claim
32 words
A photo-mask blank as claimed in claim 1, wherein said substrate comprises a transparent flat plate and a conductive and transparent film on said transparent flat plate to provide said principal surface.
Claim 13
Dependent Claim
77 words
A photo-mask for use in lithography comprising a substrate transparent to light in a predetermined wavelength region and having a principal surface, a shading layer selectively remaining on said principal surface which includes chromium and chromium carbide for shading the light in said predetermined wavelength region, and an antireflection layer only on said shading layer which includes chromium oxide and chromium nitride for reducing reflection of light in at least a part of said predetermined wavelength region.
Claim 14
Dependent Claim
77 words
A photo-mask for use in lithography comprising a substrate transparent to light in a predetermined wavelength region and having a principal surface, a shading layer selectively remaining on said principal surface which includes chromium and chromium carbide for shading the light in said predetermined wavelength region, and an antireflection layer only on said shading layer which includes chromium oxide and chromium nitride for reducing reflection of light in at least a part of said predetermined wavelength region.
Claim 15
Dependent Claim
20 words
A photo-mask as claimed in claim 12 wherein said shading layer and said antireflection layer have substantially equal etch rates.
Claim 16
Dependent Claim
23 words
A photo-mask as claimed in claim 13 wherein said shading layer and antireflection layer are substantially coextensive without undercuts in said shading layer.
Claim 17
Dependent Claim
29 words
A photo-mask as claimed in claim 12 constituted as a composite consisting of said substrate with said shading layer and said antireflection layer applied thereto as a two-layer covering.
Claim 18
Dependent Claim
31 words
A photo-mask as claimed in claim 12 wherein said shading layer consists essentially of said chromium and chromium carbide and said anti-reflection layer consists essentially of chromium oxide and chromium nitride.
Claim 19
Dependent Claim
28 words
A photo-mask as claimed in claim 16 wherein said shading layer is sputter deposited on said substrate and said anti-reflection layer is sputter deposited on said shading layer.
Claim 20
Dependent Claim
37 words
A photo-mask as claimed in claim 12, said photo-mask having a relatively flat characteristic of reflection index (%) vs wavelength (nm) in the region of 360-600 nm in which the reflection index is between 11 and 20%.
Claim 21
Dependent Claim
23 words
A photo-mask as claimed in claim 18 wherein the reflection index has a minimum value at a wavelength between 400 and 500 nm.
Claim 22
Dependent Claim
25 words
A photo-mask as claimed in claim 12 wherein the chromium and chromium carbide of the shading layer coexist in the form of interstitial chromium carbide.
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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) | 1988-07-22 | 1989-01-21 | 1989-07-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-07-22 | 1993-01-21 | 1993-07-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-07-22 | 1997-01-21 | 1997-07-23 | $7700.00 | Window Closed / Lapsed |