US4390592A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Low temperature reduction process for photomasks
Assignee: PPG Industries Inc
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Filing: 1981-11-20
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Granted: 1983-06-28
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Expires: 2001-11-20
Abstract
Abstract Glass photomasks having a high resolution stain pattern for use in photofabrication processes are made by migrating stain-producing ions into the surface of a glass substrate, and reducing and agglomerating the stain-producing ions in the presence of pure hydrogen under pressure at relatively low temperatures to produce a high resolution stain pattern.
Inventors
- 👤 Fred M. Ernsberger
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 20:20
CPC Classifications
G; G03; G03F; G03F1/00; G03F1/68; G03F1/76; G03F1/78; C; C03; C03C; C03C21/00; C03C21/001; C03C21/005; C03C23/00; C03C23/007; G03F1/54; Y; Y10; Y10T; Y10T428/00; Y10T428/24; Y10T428/24777; Y10T428/31; Y10T428/315
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
76 words
In a method for producing a stain pattern in a glass substrate comprising the steps of injecting stain-producing cations into a surface of a glass substrate and heating the glass in the presence of a reducing agent to reduce and agglomerate the stain-producing cations to produce a stain pattern within the surface of the glass, the improvement which comprises utilizing hydrogen under superatmospheric pressure as the reducing agent at a temperature less than about 300° C.
Claim 2
Dependent Claim
76 words
In a method for producing a stain pattern in a glass substrate comprising the steps of injecting stain-producing cations into a surface of a glass substrate and heating the glass in the presence of a reducing agent to reduce and agglomerate the stain-producing cations to produce a stain pattern within the surface of the glass, the improvement which comprises utilizing hydrogen under superatmospheric pressure as the reducing agent at a temperature less than about 300° C.
Claim 3
Dependent Claim
21 words
The method of claim 1, wherein the stain-producing cations are selected from the group consisting of silver, copper, gold and thallium.
Claim 4
Dependent Claim
34 words
The method of claim 1, wherein the step of injecting stain-producing ions into the glass surface is carried out at a temperature from 100° to 200° C. in the presence of an electric field.
Claim 5
Dependent Claim
23 words
The method of claim 1, wherein the stain-producing ions are injected into the glass surface to a depth not greater than one micron.
Claim 6
Dependent Claim
30 words
The method of claim 1, wherein the step of reducing and agglomerating the stain-producing ions is carried out in the presence of hydrogen at a pressure greater than ten atmospheres.
Claim 7
Dependent Claim
41 words
The method of claim 5, wherein the step of reducing and agglomerating the stain-producing ions is carried out in the presence of pure hydrogen at a pressure greater than 1000 pounds per square inch at a temperature less than 200° C.
Claim 8
Dependent Claim
30 words
An article of manufacture prepared in accordance with the method of claim 1, wherein the stain pattern has an optical density of at least 2.0 with respect to ultraviolet radiation.
Claim 9
Dependent Claim
34 words
An article of manufacture comprising a transparent glass substrate and within said glass substrate a pattern of stain-producing metal wherein the roll-off region of the pattern edges is not more than one micron wide.
Claim 10
Dependent Claim
34 words
An article of manufacture comprising a transparent glass substrate and within said glass substrate a pattern of stain-producing metal wherein the roll-off region of the pattern edges is not more than one micron wide.
Claim 11
Dependent Claim
29 words
An article according to claim 8, wherein the stain-producing metal is silver and the depth of silver penetration from the nearest glass surface is not more than one micron.
Claim 12
Dependent Claim
22 words
An article according the claim 9, wherein the optical density of the silver is at least 2.0 with respect to ultraviolet radiation.
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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) | 1986-06-27 | 1986-12-27 | 1987-06-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-06-27 | 1990-12-27 | 1991-06-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-06-27 | 1994-12-27 | 1995-06-28 | $7700.00 | Window Closed / Lapsed |