US4351894A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of manufacturing a semiconductor device using silicon carbide mask
Assignee: Toshiba Corp
•
Filing: 1981-05-12
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Granted: 1982-09-28
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Expires: 2001-05-12
Abstract
Abstract A method of manufacturing a semiconductor device which comprises the step of applying a silicon carbide film having a prescribed perforated pattern as a masking film selectively to etch a silicon dioxide film or diffuse an impurity into a substrate.
Inventors
- 👤 Toshio Yonezawa
- 👤 Takashi Ajima
- 👤 Shunichi Hiraki
- 👤 Yutaka Koshino
- 👤 Yoshitami Oka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 09:15
CPC Classifications
H; H10; H10P; H10P14/00; H10P14/60; H10P14/69; H10P14/6903; H10P14/6905; H10P14/63; H10P14/6326; H10P14/6328; H10P14/6329; H10P14/6334; H10P14/6336; H10P14/66; H10P14/662; H10P14/692; H10P14/6921; H10P14/69215; H10P50/00; H10P50/20; H10P50/28; H10P50/282; H10P50/283; H10P50/73; H10P76/00; H10P76/40; Y; Y10; Y10S; Y10S438/00; Y10S438/942; Y10S438/945; Y10S438/948; Y10S438/95; Y10S438/951
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
150 words
A method of preparing a silicon dioxide film perforated in a prescribed pattern, the film to be used as a mask on the surface of semiconductor material for manufacture of a dimensionally precise semiconductor device, the method comprising: (a) forming a silicon dioxide film substantially covering the surface of the semiconductor material, (b) forming a silicon carbide film substantially and adheringly covering said silicon dioxide film, (c) forming a photoresist mask perforated in the prescribed pattern on said silicon carbide film, (d) perforating said silicon carbide film in the prescribed pattern using said photoresist mask, thereby providing a silicon carbide mask for said silicon dioxide film, and (e) selectively etching said silicon dioxide film using hydrofluoric acid or ammonium fluoride through the perforations having the prescribed pattern in said silicon carbide mask, thereby providing a dimensionally precise silicon dioxide mask for diffusion of an impurity or deposition of an electrode.
Claim 2
Independent Claim
150 words
A method of preparing a silicon dioxide film perforated in a prescribed pattern, the film to be used as a mask on the surface of semiconductor material for manufacture of a dimensionally precise semiconductor device, the method comprising: (a) forming a silicon dioxide film substantially covering the surface of the semiconductor material, (b) forming a silicon carbide film substantially and adheringly covering said silicon dioxide film, (c) forming a photoresist mask perforated in the prescribed pattern on said silicon carbide film, (d) perforating said silicon carbide film in the prescribed pattern using said photoresist mask, thereby providing a silicon carbide mask for said silicon dioxide film, and (e) selectively etching said silicon dioxide film using hydrofluoric acid or ammonium fluoride through the perforations having the prescribed pattern in said silicon carbide mask, thereby providing a dimensionally precise silicon dioxide mask for diffusion of an impurity or deposition of an electrode.
Claim 3
Dependent Claim
33 words
The method according to claim 1 wherein in the step (b) the silicon carbide film is formed by sputtering, and in the step (c) the silicon carbide film is perforated by plasma etching.
Claim 4
Dependent Claim
23 words
The method according to claim 1, wherein a silicon carbide film used as a masking film is left intact in the semiconductor device.
Claim 5
Dependent Claim
19 words
The method according to claim 1, wherein the silicon carbide film used as a masking film is later removed.
Claim 6
Dependent Claim
25 words
The method according to claim 1 wherein the silicon carbide film is formed uniformly all over the underlying silicon dioxide film by chemical vapor deposition.
Claim 7
Dependent Claim
32 words
The method according to claim 1 wherein the silicon carbide film is formed uniformly all over the underlying silicon dioxide film and the silicon carbide film is selectively etched by plasma etching.
Claim 8
Dependent Claim
15 words
The method according to claim 1, wherein the silicon carbide film has a crystalline structure.
Claim 9
Dependent Claim
15 words
The method according to claim 1, wherein the silicon carbide film has an amorphous structure.
Claim 10
Dependent Claim
53 words
The method according to claim 1, wherein the silicon carbide film contains at least one impurity selected from the group consisting of phosphorus, aluminium, lead, boron, titanium, gallium, zinc, zirconium, strontium, chromium, molybdenum, tungsten, nickel, iron, cobalt, arsenic and tantalum at a concentration ranging from 10 19 to 10 22 atom/cm 3 .
Claim 11
Dependent Claim
21 words
The method according to claim 1 wherein said formed silicon dioxide film is for diffusing an impurity into the semiconductor substrate.
Claim 12
Dependent Claim
20 words
The method according to claim 1 wherein said formed silicon dioxide film is for depositing electrodes onto the semiconductor substrate.
Claim 13
Dependent Claim
23 words
The method according to claim 1, wherein the silicon carbide film is formed uniformly all over the underlying silicon dioxide film by sputtering.
Claim 14
Dependent Claim
24 words
The method according to claim 1, wherein the silicon carbide film is formed uniformly all over the underlying silicon dioxide film by plasma deposition.
Claim 15
Dependent Claim
32 words
The method according to claim 1, wherein the silicon carbide film is formed uniformly all over the underlying silicon dioxide film and the silicon carbide film is selectively etched by electrolytic etching.
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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) | 1985-09-27 | 1986-03-29 | 1986-09-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-09-27 | 1990-03-29 | 1990-09-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-09-27 | 1994-03-29 | 1994-09-28 | $7700.00 | Window Closed / Lapsed |