US3629022A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Use of platinum thin films as mask in semiconductor processing
Assignee: Motorola Solutions Inc
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Filing: 1968-03-20
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Granted: 1971-12-21
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Expires: 1988-03-20
Abstract
Abstract Platinum thin films are selectively etched by a method that begins with the deposition of an aluminum film on the platinum film. The reverse image of that desired in the platinum film is then patterned in the aluminum. The combination is heated to 400* to 500* C. for a time sufficient to form a platinumaluminum intermetallic compound. The intermetallic compound is then readily removed by etching whereby the remaining platinum is delineated in the reverse of the aluminum pattern.
Inventors
- 👤 Lewis Terry
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 09:35
CPC Classifications
H; H10; H10P; H10P95/00; H10W; H10W20/00; H10W20/40; H10W72/00; H10W72/20; Y; Y10; Y10S; Y10S438/00; Y10S438/942; Y10S438/945
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
20 words
A method as defined by claim 1 wherein the first, second and third films are titanium, platinum and aluminum, respectively.
Claim 2
Independent Claim
110 words
A method for etching, comprising the steps of: depositing a first metal film selected from the platinum-palladium family on a semiconductor; depositing on said first metal film a second film selected from the group comprising aluminum and silicon for forming with said first film a compound of greater etchability; patterning said second film for forming a reverse image of that desired in said first metal film; heating said first metal film in combination with said second film to a temperature sufficient to form said compound of greater etchability; and etchably removing said compound whereby; said remaining first metal film is delineated in the reverse image formEd in said second film.
Claim 3
Dependent Claim
22 words
The method as recited in claim 3, wherein said heating step is performed within a temperature range of 400* to 500* C.
Claim 4
Dependent Claim
74 words
The method as recited in claim 3, wherein: said first metal layer comprises platinum, said second layer comprises aluminum; said etchably removing step, further comprises: immersing said platinum and aluminum structure in an etchant selected from the group comprising potassium hydroxide and sodium hydroxide for removing the aluminum-rich portion of said compound; and immersing said platinum and aluminum structure in an etchant of aqua regia for removing the platinum rich portion of said compound.
Claim 5
Dependent Claim
56 words
The method as recited in claim 2 wherein said etching step further comprises; immersing said structure in an etchant selected from the group comprising potassium hydroxide and sodium hydroxide for removing the aluminum-rich portion of said intermetallic compound; and immersing said structure in an etchant of aqua regia for removing the platinum-rich portion of said compound.
References Cited (Backward Citations)
US3231421A
Cited
US3370948A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-12-20 | 1975-06-21 | 1975-12-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-12-20 | 1979-06-21 | 1979-12-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-12-20 | 1983-06-21 | 1983-12-21 | $7700.00 | Window Closed / Lapsed |