US3616349A
Expired / Lapsed
US
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Method for etching chromium oxide films
Assignee: Corning Glass Works
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Filing: 1968-07-30
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Granted: 1971-10-26
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Expires: 1988-07-30
Abstract
Abstract A method of etching using weaker acid etchant solutions than heretofore possible wherein interaction between the chloride ions in solution and the film is initiated by producing an electrical potential across a thin oxide layer on the film sufficient to allow the chloride ions to permeate therethrough. Because a weaker etchant can be used in the process, thinner and softer photoresistive protective coatings can also be used for obtaining decorative film patterns, microcircuit masks, and the like. Further, the rate at which etching proceeds can now be controlled over a wider range than heretofore possible, thus effecting the amount of undercutting of the acid-resistant mask by the etchant.
Inventors
- 👤 Raymond E Szupillo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 07:27
CPC Classifications
C; C25; C25F; C25F3/00; C25F3/02
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
41 words
The method of claim 1 wherein the step of applying an electrical potential comprises contacting an oxidized surface portion of said film with an electrode of material selected from the group consisting of those elements in the electrochemical series above chromium.
Claim 2
Dependent Claim
35 words
The method of claim 1 wherein the step of applying an electrical potential comprises contacting an oxidized surface of said film with an electrode of material selected from the group consisting of aluminum and zinc.
Claim 3
Dependent Claim
18 words
The method of claim 1 further comprising masking selected portions of said film against attack by said ions.
Claim 4
Dependent Claim
65 words
The method of claim 1 wherein the step of applying an electrical potential comprises contacting an oxidized surface portion of said film with a first electrode of inert material with respect to said solution, contacting said solution with a second electrode of inert material with respect to said solution, and applying an electrical potential Difference between said first and second electrodes external to said solution.
Claim 5
Dependent Claim
26 words
The method of claim 1 wherein the step of contacting said oxide layer with an etching solution comprises immersing said oxide-coated film in said etching solution.
Claim 6
Dependent Claim
41 words
The method of claim 1 which further comprises the step of removing said electrical potential after initiation of said self-sustaining chemical reaction between said chromium film and said etching solution to permit said chemical reaction to continue without said electrical potential.
Claim 7
Independent Claim
121 words
A method of producing a patterned article by etching a film of chromium deposited on a substrate, comprising the steps of forming said chromium film on said substrate, forming a thin surface oxide layer on said chromium film, applying a masking material to selected areas of said oxide layer, contacting the unmasked portions of said oxide layer with an acid etching solution having a chloride ion concentration so adjusted that the solution will not chemically react with the oxide-covered chromium film in the absence of an electrical potential but will react with chromium metal at a predetermined rate, and applying an electrical potential across said oxide layer to initiate a self-sustaining chemical reaction between said chromium film and said etching solution.
Claim 8
Dependent Claim
26 words
The method of claim 8 wherein the step of contacting said oxide layer with an etching solution comprises immersing said oxide-coated film in said etching solution.
Claim 9
Dependent Claim
37 words
The method of claim 9 wherein the step of applying an electrical potential comprises contacting said oxide layer with an electrode of material selected from the group consisting of those elements in the electrochemical series above chromium.
Claim 10
Dependent Claim
61 words
The method of claim 9 wherein the step of applying an electrical potential comprises contacting said oxide layer with a first electrode of inert material with respect to said solution, contacting said solution with a second electrode of inert material with respect to said solution, and applying an electrical potential difference between said first and second electrodes external to said solution.
Claim 11
Dependent Claim
41 words
The method of claim 12 which further comprises the step of removing said electrical potential after initiation of said self-sustaining chemical reaction between said chromium film and said etching solution to permit said chemical reaction to continue without said electrical potential.
Claim 12
Independent Claim
91 words
A method of etching a film of chromium deposited on a substrate comprising forming said chromium film on said substrate, forming a thin surface oxide layer on said chromium film, contacting said oxide layer with an acid etching solution having a chloride ion concentration so adjusted that the solution will not chemically react with the oxide-covered chromium film but will react with chromium metal at a predetermined rate, and applying an electrical potential across said oxide layer to initiate a self-sustaining chemical reaction between said chromium film and said etching solution.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-10-25 | 1975-04-26 | 1975-10-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-10-25 | 1979-04-26 | 1979-10-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-10-25 | 1983-04-26 | 1983-10-26 | $7700.00 | Window Closed / Lapsed |