US4923562A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Processing of etching refractory metals
Assignee: Texas Instruments Inc
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Filing: 1988-12-01
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Granted: 1990-05-08
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Expires: 2008-12-01
Abstract
Abstract A processing apparatus and method for anisotropically etching thin film metal (e.g. tungsten) under plasma bombardment conditions by using a feed gas mixture which includes a fluorine source (such as SF 6 ) plus a bromine source (such as HBr), plus a very weak oxygen source (e.g. carbon monoxide). This chemistry provides anisotropic high rate fluoro-etching with good selectivity to photoresist.
Inventors
- 👤 Rhett B. Jucha
- 👤 Cecil J. Davis
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 05:09
CPC Classifications
H; H10; H10P; H10P50/00; H10P50/20; H10P50/26; H10P50/264; H10P50/266; H10P50/267
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
108 words
A method for etching refractory metals on a wafer comprising: (a) transferring a wafer in to a vacuum processing chamber; (b) applying a pressure to said processing chamber less than ambient to maintain said processing chamber at lessthan ambient; (c) providing fluorine containing gas to a plasma generating chamber remote from said processing chamber and producing free radicals using microwave energy excitation of the fluorine containing gas; (d) adding a bromine containing gas and a resist selectivity enhancement gas to said free radicals to form a gas mixture; (e) flowing the gas mixture over said wafer disposed within said processing chamber; and (f) etching said refractory metal layer.
Claim 2
Independent Claim
108 words
A method for etching refractory metals on a wafer comprising: (a) transferring a wafer in to a vacuum processing chamber; (b) applying a pressure to said processing chamber less than ambient to maintain said processing chamber at lessthan ambient; (c) providing fluorine containing gas to a plasma generating chamber remote from said processing chamber and producing free radicals using microwave energy excitation of the fluorine containing gas; (d) adding a bromine containing gas and a resist selectivity enhancement gas to said free radicals to form a gas mixture; (e) flowing the gas mixture over said wafer disposed within said processing chamber; and (f) etching said refractory metal layer.
Claim 3
Dependent Claim
20 words
A method as in claim 1 further including the step of introducing an oxygen source gas into said process chamber.
Claim 4
Independent Claim
89 words
A method of etching a tungsten film on a wafer comprising: (a) disposing said wafer in a process chamber at low pressure; (b) generating free radicals from a source of fluorine containing gas in a plasma generating chamber remote from the process chamber using microwave energy excitation of the fluorine containing gas; (c) introducing the free radicals into said chamber to a face to said wafer; (d) introducing a source of bromine and a resist selectivity enhancement gas into said process chamber; and (e) etching said tungsten metal layer.
Claim 5
Independent Claim
89 words
A method of etching a tungsten film on a wafer comprising: (a) disposing said wafer in a process chamber at low pressure; (b) generating free radicals from a source of fluorine containing gas in a plasma generating chamber remote from the process chamber using microwave energy excitation of the fluorine containing gas; (c) introducing the free radicals into said chamber to a face to said wafer; (d) introducing a source of bromine and a resist selectivity enhancement gas into said process chamber; and (e) etching said tungsten metal layer.
Claim 6
Dependent Claim
24 words
The process as set forth in claim 3 wherein said steps of introducing are preformed at least in part during the same time period.
Claim 7
Dependent Claim
44 words
The process as set forth in claim 3 wherein the source of fluorine is taken from the group of SF 6 , NF 3 , CF 4 , C 2 F 6 , HF, F 2 , SiF 4 , and BF 3 .
Claim 8
Dependent Claim
24 words
The process as set forth in claim 3 wherein the source of bromine is taken from the group of HBr and CF 3 Br.
Claim 9
Dependent Claim
27 words
The process as set forth in claim 3 wherein the enhancement gas is taken from the group of CO, NO, CH 4 , and CHF 3 .
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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) | 1993-05-07 | 1993-11-06 | 1994-05-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-05-07 | 1997-11-06 | 1998-05-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-05-07 | 2001-11-06 | 2002-05-08 | $7700.00 | Window Closed / Lapsed |