Patent US3607448A successfully refreshed from Google Patents.
US3607448A
Expired / Lapsed
US
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Chemical milling of silicon carbide
Assignee: Raytheon Co
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Filing: 1968-10-21
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Granted: 1971-09-21
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Expires: 1988-10-21
Abstract
Abstract The method comprises the steps of (1) placing molybdenum on a silicon carbide specimen, (2) alloying the molybdenum into the silicon carbide, (3) performing, if desired, ion implantation or other process steps, utilizing the molybdenum as a mask, (4) etching away the molybdenum alloy such as by sodium peroxide. The method permits the use of low temperature operations.
Inventors
- 👤 Howard L Dunlap
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 17:44
CPC Classifications
C; C04; C04B; C04B41/00; C04B41/53; C04B41/5338; C04B41/5346; H; H10; H10P; H10P50/00; Y; Y10; Y10S; Y10S148/00; Y10S148/051; Y10S148/084; Y10S148/106; Y10S148/148; Y10S438/00; Y10S438/931; Y10S438/942; Y10S438/945
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
38 words
A method as in claim 1 for etching a desired geometrical configuration into the specimen at the desired locations further comprising the step of shaping the molybdenum in the geometrical configuration desired to be etched into the specimen.
Claim 2
Dependent Claim
48 words
A method as in claim 1 further including the prereacting steps of utilizing the alloy as a mask and doping the alloyed crystal by ion implantation process to provide a doped area of the specimen at locations other than the desired locations when said reacting step is performed.
Claim 3
Independent Claim
42 words
A method for chemically milling at least a portion of a specimen of silicon carbide comprising the steps of: utilizing the silicon carbide specimen alloyed with molybdenum at, at least, the portion thereof and removing the alloyed molybdenum portion from the specimen.
Claim 4
Dependent Claim
27 words
A method as in claim 4 further comprising the steps of utilizing the molybdenum alloy portion as a mask and doping the specimen before said removing step.
Claim 5
Dependent Claim
17 words
A method as in claim 5 wherein said doping step comprises the use of ion implantation techniques.
Claim 6
Dependent Claim
38 words
A method as in claim 4 wherein said removing step comprises the use of an etchant at a temperature sufficiently high and for a time sufficiently long to produce a chemical reaction between said etchant and the alloy.
Claim 7
Dependent Claim
27 words
A method as in claim 7 wherein said etchant consists of the group selected from sodium hydroxide, borax, sodium carbonate, potassium carbonate, sodium peroxide and combinations thereof.
Claim 8
Dependent Claim
22 words
A method as in claim 7 wherein said etchant consists of a sodium peroxide melt at a temperature of approximately 500* C.
Claim 9
Dependent Claim
54 words
A method as in claim 4 further comprising the step of preparing the silicon carbide specimen having the molybdenum alloy therein, said preparing step comprising the steps of placing molybdenum on a silicon carbide crystal and heating the molybdenum and the silicon carbide crystal sufficiently to alloy the molybdenum into the silicon carbide crystal.
Claim 10
Dependent Claim
17 words
A method as in claim 4 comprising the prealloying step of placing the molybdenum in the specimen.
Claim 11
Dependent Claim
25 words
A method as in claim 11 wherein said placing step comprises the steps of utilizing a molybdenum paste and drying the paste on the specimen.
Claim 12
Dependent Claim
36 words
A method as in claim 11 wherein the portion is provided with a specified geometrical configuration further comprising the step of shaping the molybdenum in the specified geometrical configuration desired to be etched into the specimen.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-09-20 | 1975-03-22 | 1975-09-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-09-20 | 1979-03-22 | 1979-09-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-09-20 | 1983-03-22 | 1983-09-21 | $7700.00 | Window Closed / Lapsed |