US4666555A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Plasma etching of silicon using fluorinated gas mixtures
Assignee: Intel Corp
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Filing: 1985-08-23
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Granted: 1987-05-19
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Expires: 2005-08-23
Abstract
Abstract A method of plasma etching silicon using a fluorinated gas mixture. A mixture of CHF3 and SF6 is utilized in an etch chamber to form a plasma for etching silicon. The degree of anisotropy of the etch can be controlled by changing the percentage of CHF3 in the CHF3/SF6 mixture. The method does not adversely affect the etched surface so that no post-etch thermal process step is required to cure the silicon surface.
Inventors
- 👤 Chi-Hwa Tsang
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 22:53
CPC Classifications
H; H10; H10P; H10P50/00; H10P50/20; H10P50/24; H10P50/242
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
52 words
An improvement in the method of etching silicon semiconductor material with a plasma formed from a gas mixture, said improvement comprising: forming said plasma from a first amount of CHF3 in combination with a second amount of SF6, said first amount greater than said second amount; whereby an anisotropic etch is achieved.
Claim 2
Dependent Claim
52 words
An improvement in the method of etching silicon semiconductor material with a plasma formed from a gas mixture, said improvement comprising: forming said plasma from a first amount of CHF3 in combination with a second amount of SF6, said first amount greater than said second amount; whereby an anisotropic etch is achieved.
Claim 3
Dependent Claim
18 words
The improvement as described by claim 1 wherein said first amount is approximately four times said second amount.
Claim 4
Dependent Claim
20 words
The improvement as described by claim 1 wherein said plasma is formed at an RF energy of approximately 600 watts.
Claim 5
Dependent Claim
75 words
An improved method for plasma etching of silicon semiconductor material comprising: forming a layer of photoresist on the surface of said silicon; defining openings in said photoresist to expose predetermined areas of said surface of said silicon; introducing a mixture of SF6 and CHF3 gas to said silicon; applying electrical energy to said gas mixture to form a plasma; etching said silicon with said plasma to a desired depth; whereby said silicon is etched anisotropically.
Claim 6
Dependent Claim
75 words
An improved method for plasma etching of silicon semiconductor material comprising: forming a layer of photoresist on the surface of said silicon; defining openings in said photoresist to expose predetermined areas of said surface of said silicon; introducing a mixture of SF6 and CHF3 gas to said silicon; applying electrical energy to said gas mixture to form a plasma; etching said silicon with said plasma to a desired depth; whereby said silicon is etched anisotropically.
Claim 7
Dependent Claim
19 words
The method as described by claim 4 wherein said gas mixture comprises approximately 80% CHF3 and approximately 20% SF6.
Claim 8
Dependent Claim
15 words
The method as defined by claim 4 wherein said electrical energy comprises approximately 600 watts.
Claim 9
Dependent Claim
23 words
The method as defined by claim 4 wherein said gas mixture is introduced to said silicon at a rate of approximately 125 sccm.
Claim 10
Dependent Claim
25 words
The method as described by claim 4 wherein the degree of said anisotropy is dependant on the percentage of CHF3 in said gas mixture combination.
References Cited (Backward Citations)
US4601782A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-05-18 | 1990-11-17 | 1991-05-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-05-18 | 1994-11-17 | 1995-05-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-05-18 | 1998-11-17 | 1999-05-19 | $7700.00 | Window Closed / Lapsed |