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Patent US4097394A successfully refreshed from Google Patents.
US4097394A
Expired / Lapsed
US
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Etching liquid for etching aluminum
Assignee: US Philips Corp
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Filing: 1977-05-02
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Granted: 1978-06-27
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Expires: 1997-05-02
Abstract
Abstract Etching liquid for selectively etching aluminum and alloys, which consists of a solution of carbonate and/or hydroxide, phosphate and ferricyanide. This etching liquid gives products having very good boundary resolution and little undercutting.
Inventors
- 👤 Gijsbertus Gerlach
- 👤 John Joseph Kelly
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 20:34
CPC Classifications
H; H10; H10P; H10P50/00; H10P50/60; H10P50/66; H10P50/663; H10P50/667; C; C23; C23F; C23F1/00; C23F1/10; C23F1/14; C23F1/32; C23F1/36; H10P95/00
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
119 words
An etching solution for selectively etching layers at least 100 μ thick of aluminum and alloys of aluminum, said solution having a pH of at least 11.5 and being an aqueous solution of at least one alkaline material selected from the group consisting of alkali metal carbonates and alkali metal hydroxides in an amount of from 0.1 to 2 mole/l, a soluble ferricyanide in an amount of from 5 g/l to saturation, the molar ratio of hydroxide to ferricyanide being at most equal to 1 and a soluble salt of a phosphorus acid derived from trivalent or pentavalent phosphorous oxide selected from the group consisting of orthophosphates, metaphosphates, polyphosphates, pyrophosphates and phosphites in an amount sufficient to reduce undercutting.
Claim 2
Dependent Claim
119 words
An etching solution for selectively etching layers at least 100 μ thick of aluminum and alloys of aluminum, said solution having a pH of at least 11.5 and being an aqueous solution of at least one alkaline material selected from the group consisting of alkali metal carbonates and alkali metal hydroxides in an amount of from 0.1 to 2 mole/l, a soluble ferricyanide in an amount of from 5 g/l to saturation, the molar ratio of hydroxide to ferricyanide being at most equal to 1 and a soluble salt of a phosphorus acid derived from trivalent or pentavalent phosphorous oxide selected from the group consisting of orthophosphates, metaphosphates, polyphosphates, pyrophosphates and phosphites in an amount sufficient to reduce undercutting.
Claim 3
Dependent Claim
15 words
The etching solution of claim 1 wherein the alkaline material is an alkali metal hydroxide.
Claim 4
Dependent Claim
15 words
The etching solution of claim 1 wherein the alkaline material is an alkali metal carbonate.
Claim 5
Dependent Claim
120 words
An etching solution for selectively etching layers of aluminum and alloys of aluminum partially covered with a noble metal, said solution having a pH of at least 11.5 and being an aqueous solution of at least one alkaline material selected from the group consisting of alkali metal carbonates and alkali metal hydroxides in an amount of from 0.1 to 2 mole/l, a soluble ferricyanide in an amount of from 5 g/l to saturation, the molar ratio of hydroxide to ferricyanide being at most equal to 1 and a soluble salt of a phosphorus acid derived from trivalent or pentavalent phosphorous oxide selected from the group consisting of orthophosphates, mataphosphates, polyphosphates, pyrophosphates and phosphites in an amount sufficient to reduce undercutting.
Claim 6
Dependent Claim
120 words
An etching solution for selectively etching layers of aluminum and alloys of aluminum partially covered with a noble metal, said solution having a pH of at least 11.5 and being an aqueous solution of at least one alkaline material selected from the group consisting of alkali metal carbonates and alkali metal hydroxides in an amount of from 0.1 to 2 mole/l, a soluble ferricyanide in an amount of from 5 g/l to saturation, the molar ratio of hydroxide to ferricyanide being at most equal to 1 and a soluble salt of a phosphorus acid derived from trivalent or pentavalent phosphorous oxide selected from the group consisting of orthophosphates, mataphosphates, polyphosphates, pyrophosphates and phosphites in an amount sufficient to reduce undercutting.
Claim 7
Dependent Claim
15 words
The etching solution of claim 4 wherein the alkaline material is an alkali metal hydroxide.
Claim 8
Dependent Claim
15 words
The etching solution of claim 4 wherein the alkaline material is an alkali metal carbonate.
References Cited (Backward Citations)
US3168478A
Cited
US3532569A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-06-26 | 1981-12-26 | 1982-06-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-06-26 | 1985-12-26 | 1986-06-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-06-26 | 1989-12-26 | 1990-06-27 | $7700.00 | Window Closed / Lapsed |