US4490209A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Plasma etching using hydrogen bromide addition
Assignee: Texas Instruments Inc
•
Filing: 1983-12-27
•
Granted: 1984-12-25
•
Expires: 2003-12-27
Abstract
Abstract The disclosure relates to a plasma etch chemistry which allows a near perfectly anisotropic etch of silicon. A Cl-containing compound such as HCl has HBr added thereto, readily allowing the anisotropic etching of silicon. This is due to the low volatility of SiBr4. The silicon surface facing the discharge is subjected to ion bombardment, allowing the volatilization (etching) of silicon as a Si-Cl-Br compound. The Br which adsorbs on the sidewalls of the etched silicon passivates them from the etching. This new plasma etch chemistry yields a very smooth etched surface, and the etch rate is relatively insensitive to the electrical conductivity of the silicon.
Inventors
- 👤 Dennis C. Hartman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 00:48
CPC Classifications
H; H10; H10P; H10P50/00; H10P50/20; H10P50/26; H10P50/264; H10P50/266; H10P50/267; H10P50/268; H10P50/24; H10P50/242; Y; Y10; Y10S; Y10S438/00; Y10S438/963
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
76 words
The method for selectively etching a layer of a silicon-bearing material in an integrated circuit, comprising the steps of: providing a patterned masking material over said silicon-bearing material to expose only the areas of said silicon-bearing material which are to be etched; passing a gaseous mixture over said layer; and creating a plasma discharge in said gaseous mixture adjacent to said layer of silicon-bearing material; wherein said gaseous mixture comprises hydrogen bromide and a chlorine-bearing species.
Claim 2
Independent Claim
76 words
The method for selectively etching a layer of a silicon-bearing material in an integrated circuit, comprising the steps of: providing a patterned masking material over said silicon-bearing material to expose only the areas of said silicon-bearing material which are to be etched; passing a gaseous mixture over said layer; and creating a plasma discharge in said gaseous mixture adjacent to said layer of silicon-bearing material; wherein said gaseous mixture comprises hydrogen bromide and a chlorine-bearing species.
Claim 3
Independent Claim
88 words
The method for selectively etching a layer of a silicon-bearing material in an integrated circuit, comprising the steps of: providing a patterned masking material over said silicon-bearing material to expose only the areas of said silicon-bearing material which are to be etched; passing a gaseous mixture over said layer; and creating a plasma discharge in said gaseous mixture adjacent to said layer of silicon-bearing material; wherein said gaseous mixture comprises hydrogen bromide, and at least one halogen bearing species taken from the class consisting of fluorine and chlorine.
Claim 4
Independent Claim
88 words
The method for selectively etching a layer of a silicon-bearing material in an integrated circuit, comprising the steps of: providing a patterned masking material over said silicon-bearing material to expose only the areas of said silicon-bearing material which are to be etched; passing a gaseous mixture over said layer; and creating a plasma discharge in said gaseous mixture adjacent to said layer of silicon-bearing material; wherein said gaseous mixture comprises hydrogen bromide, and at least one halogen bearing species taken from the class consisting of fluorine and chlorine.
Claim 5
Dependent Claim
26 words
The method of claim 1 wherein said chlorine-bearing species is selected from the group consisting of: silicon tetrachloride, carbon tetrachloride, phosphorus trichloride, chlorine and hydrogen chloride.
Claim 6
Dependent Claim
20 words
The method of claim 2 wherein said fluorine-bearing species is selected from the group consisting of tetrafluoromethane, hexafluoromethane and octofluoropentane.
Claim 7
Dependent Claim
23 words
The method of claim 2 wherein said gaseous mixture comprises a gas selected from the group consisting of: trifluoromethane, trifluorochloromethane, difluorodichloromethane and fluorotrichloromethane.
Claim 8
Dependent Claim
21 words
The method of claim 1 wherein the bromine-chlorine mole ratio is in the range of from about 1% to about 10%.
Claim 9
Dependent Claim
22 words
The method of claim 2 wherein the mole ratio of bromine to fluorine and/or chlorine is from about 1% to about 10%.
Claim 10
Dependent Claim
21 words
The method of claim 3 wherein the bromine-chlorine mole ratio is in the range of from about 1% to about 10%.
Claim 11
Dependent Claim
22 words
The method of claim 4 wherein the mole ratio of bromine to fluorine and/or chlorine is from about 1% to about 10%.
Claim 12
Dependent Claim
22 words
The method of claim 5 wherein the mole ratio of bromine to fluorine and/or chlorine is from about 1% to about 10%.
Claim 13
Dependent Claim
13 words
The method of claim 6 wherein the gaseous mixture includes an inert gas.
Claim 14
Dependent Claim
13 words
The method of claim 7 wherein the gaseous mixture includes an inert gas.
Claim 15
Dependent Claim
13 words
The method of claim 8 wherein the gaseous mixture includes an inert gas.
Claim 16
Dependent Claim
13 words
The method of claim 9 wherein the gaseous mixture includes an inert gas.
Claim 17
Dependent Claim
13 words
The method of claim 10 wherein the gaseous mixture includes an inert gas.
References Cited (Backward Citations)
US4450042A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-12-25 | 1988-06-25 | 1988-12-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-12-25 | 1992-06-25 | 1992-12-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-12-25 | 1996-06-25 | 1996-12-25 | $7700.00 | Window Closed / Lapsed |