US4255230A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Plasma etching process
Assignee: Eaton Corp
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Filing: 1980-02-22
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Granted: 1981-03-10
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Expires: 2000-02-22
Abstract
Abstract In an improved process for the etching of polysilicon substrates, a polysilicon substrate is exposed to plasmas of carbon tetrachloride, chlorinated gas, fluorinated gas or a gas capable of generating both chlorinated and fluorinated plasma species. The combination of a chlorinated and fluorinated etching species substantially reduces undercutting of polysilicon substrates. Improved uniformity of polysilicon etching is also achieved.
Inventors
- 👤 John Zajac
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 23:50
CPC Classifications
H; H10; H10P; H10P50/00; H10P50/20; H10P50/26; H10P50/264; H10P50/266; H10P50/267; H10P50/268
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
41 words
A process for plasma etching polysilicon substrates comprising contacting a polysilicon substrate with: (a) a plasma of carbon tetrachloride and a plasma of a chlorinated gas, and (b) a plasma of a fluorinated gas and a plasma of a chlorinated gas.
Claim 2
Dependent Claim
41 words
A process for plasma etching polysilicon substrates comprising contacting a polysilicon substrate with: (a) a plasma of carbon tetrachloride and a plasma of a chlorinated gas, and (b) a plasma of a fluorinated gas and a plasma of a chlorinated gas.
Claim 3
Dependent Claim
11 words
The process of claim 1 wherein said chlorinated gas is chlorine.
Claim 4
Dependent Claim
12 words
The process of claim 1 wherein said fluorinated gas is sulfur hexafluoride.
Claim 5
Dependent Claim
51 words
A process for the plasma etching of polysilicon substrates comprising: (a) contacting a polysilicon substrate with a first plasma of carbon tetrachloride and a chlorinated gas, (b) removing said carbon tetrachloride and chlorinated gas, and (d) contacting a said polysilicon substrate with a plasma of a fluorinated gas and chlorinated gas.
Claim 6
Dependent Claim
51 words
A process for the plasma etching of polysilicon substrates comprising: (a) contacting a polysilicon substrate with a first plasma of carbon tetrachloride and a chlorinated gas, (b) removing said carbon tetrachloride and chlorinated gas, and (d) contacting a said polysilicon substrate with a plasma of a fluorinated gas and chlorinated gas.
Claim 7
Dependent Claim
18 words
The process of claim 4 wherein said chlorinated gas is chlorine and said fluorinated gas is sulfur hexafluoride.
Claim 8
Dependent Claim
12 words
The process of claim 4 wherein said chlorinated gas comprises carbon tetrachloride.
Claim 9
Dependent Claim
12 words
The process of claim 4 wherein said fluorinated gas comprises tetra fluoromethane.
Claim 10
Dependent Claim
14 words
The process of claim 4 wherein said chlorinated gas further comprises an inert gas.
Claim 11
Dependent Claim
14 words
The process of claim 4 wherein said fluorinated gas further comprises an inert gas.
Claim 12
Dependent Claim
26 words
The process of claim 8 wherein said chlorinated gas is present in at least 50% by volume of the mixture of chlorinated gas and inert gas.
Claim 13
Dependent Claim
26 words
The process of claim 9 wherein said fluorinated gas is present in at least 50% by volume of the mixture of fluorinated gas and inert gas.
Claim 14
Dependent Claim
27 words
The process of claim 10 wherein said chlorinated gas is present in an amount approximately 72% by volume of the mixture of chlorinated gas and inert gas.
Claim 15
Dependent Claim
27 words
The process of claim 11 wherein said fluorinated gas is present in an amount approximately 78% by volume of the mixture of fluorinated gas and inert gas.
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) | 1984-03-09 | 1984-09-08 | 1985-03-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-03-09 | 1988-09-08 | 1989-03-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-03-09 | 1992-09-08 | 1993-03-10 | $7700.00 | Window Closed / Lapsed |