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US5211807A
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US
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Titanium-tungsten etching solutions
Assignee: Microelectronics and Computer Technology Corp
•
Filing: 1991-07-02
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Granted: 1993-05-18
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Expires: 2011-07-02
Abstract
Abstract Etchant solutions for titanium-tungsten, which include at least one oxidizing agent and at least one fluoride salt. Also disclosed is a method for etching TiW utilizing these etchants.
Inventors
- 👤 Ian Y. K. Yee
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 22:06
CPC Classifications
C; C23; C23F; C23F1/00; C23F1/10; C23F1/14
Claims Analysis
Total Claims: 29
Claim 1
Independent Claim
46 words
A method for etching TiW, comprising the steps of applying an etchant solution to TiW, wherein said solution comprises at least one oxidizing agent and at least one fluoride salt, and buffering the solution to maintain a pH in the range of approximately 7 to 9.
Claim 2
Independent Claim
46 words
A method for etching TiW, comprising the steps of applying an etchant solution to TiW, wherein said solution comprises at least one oxidizing agent and at least one fluoride salt, and buffering the solution to maintain a pH in the range of approximately 7 to 9.
Claim 3
Dependent Claim
17 words
The method of claim 1 wherein the etching solution is applied by immersion in an etch bath.
Claim 4
Dependent Claim
16 words
The method of claim 1 wherein the etching solution is applied by a spray etch system.
Claim 5
Independent Claim
25 words
A method for etching TiW, comprising the step of applying an etching solution to TiW, wherein said solution comprises potassium ferricyanide and a fluoride salt.
Claim 6
Independent Claim
25 words
A method for etching TiW, comprising the step of applying an etching solution to TiW, wherein said solution comprises potassium ferricyanide and a fluoride salt.
Claim 7
Dependent Claim
20 words
An etchant for etching titanium-tungsten mixtures and alloys and layered combinations of same, comprising potassium ferricyanide and a fluoride salt.
Claim 8
Dependent Claim
20 words
An etchant for etching titanium-tungsten mixtures and alloys and layered combinations of same, comprising potassium ferricyanide and a fluoride salt.
Claim 9
Dependent Claim
12 words
An etchant as claimed in claim 5, further comprising a buffering agent.
Claim 10
Dependent Claim
13 words
An etchant as claimed in claim 5, wherein said fluoride salt is soluble.
Claim 11
Dependent Claim
14 words
An etchant as claimed in claim 7, wherein said fluoride salt is ammonium fluoride.
Claim 12
Dependent Claim
14 words
An etchant as claimed in claim 7, wherein said fluoride salt is potassium fluoride.
Claim 13
Dependent Claim
19 words
An etchant as claimed in claim 6, wherein said buffer comprises a positive ion common to said oxidizing agent.
Claim 14
Dependent Claim
21 words
An etchant for etching titanium-tungsten mixtures and alloys and layered combinations of same, comprising ammonium persulfate, ammonium fluoride and ammonium hydroxide.
Claim 15
Dependent Claim
21 words
An etchant for etching titanium-tungsten mixtures and alloys and layered combinations of same, comprising ammonium persulfate, ammonium fluoride and ammonium hydroxide.
Claim 16
Dependent Claim
30 words
An etchant as claimed in claim 11, wherein the solution includes about 150-200 g/L of ammonium persulfate, about 60-70 g/L of ammonium fluoride and about 32-40 g/L of ammonium hydroxide.
Claim 17
Dependent Claim
19 words
An etchant as claimed in claim 12, wherein the pH of the solution ranges from about 8.5 to 9.
Claim 18
Dependent Claim
24 words
An etchant for etching titanium-tungsten mixtures and alloys and layered combinations of same, comprising potassium ferricyanide, potassium hydroxide, potassium phosphate monobasic and ammonium fluoride.
Claim 19
Dependent Claim
24 words
An etchant for etching titanium-tungsten mixtures and alloys and layered combinations of same, comprising potassium ferricyanide, potassium hydroxide, potassium phosphate monobasic and ammonium fluoride.
Claim 20
Dependent Claim
37 words
An etchant as claimed in claim 14, wherein the solution comprises about 25-45 g/L of potassium ferricyanide, about 10-15 g/L of potassium hydroxide, about 30-40 g/L of potassium phosphate monobasic and about 60-80 g/L of ammonium fluoride.
Claim 21
Dependent Claim
36 words
An etchant for etching titanium-tungsten mixtures and alloys and layered combinations of same, comprising an oxidizing agent, a fluoride salt, and a buffering agent to maintain a pH in the range of approximately 7 to 9.
Claim 22
Dependent Claim
36 words
An etchant for etching titanium-tungsten mixtures and alloys and layered combinations of same, comprising an oxidizing agent, a fluoride salt, and a buffering agent to maintain a pH in the range of approximately 7 to 9.
Claim 23
Dependent Claim
17 words
An etchant as claimed in claim 16, wherein said oxidizing agent is ammonium persulfate or potassium ferricyanide.
Claim 24
Dependent Claim
14 words
An etchant as claimed in claim 17, wherein said oxidizing agent is ammonium persulfate.
Claim 25
Dependent Claim
14 words
An etchant as claimed in claim 17, wherein said oxidizing agent is potassium ferricyanide.
Claim 26
Dependent Claim
13 words
An etchant as claimed in claim 16, wherein said fluoride salt is soluble.
Claim 27
Dependent Claim
14 words
An etchant as claimed in claim 20, wherein said fluoride salt is ammonium fluoride.
Claim 28
Dependent Claim
14 words
An etchant as claimed in claim 20, wherein said fluoride salt is potassium fluoride.
Claim 29
Dependent Claim
19 words
An etchant as claimed in claim 16, wherein said buffer comprises a positive ion common to said oxidizing agent.
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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) | 1996-05-17 | 1996-11-16 | 1997-05-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-05-17 | 2000-11-16 | 2001-05-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-05-17 | 2004-11-16 | 2005-05-18 | $7700.00 | Window Closed / Lapsed |