US4842687A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for etching tungsten
Assignee: Texas Instruments Inc
•
Filing: 1988-05-25
•
Granted: 1989-06-27
•
Expires: 2008-05-25
Abstract
Abstract A thin film metal (e.g. tungsten) is anisotropically etched 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 hydrocarbon source, e.g., an alkyl, such as methane. This passivating chemistry provides a very robust passivant which will provide highly anisotropic high rate flow etching, and will also improve the 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 07:57
CPC Classifications
H; H10; H10P; H10P72/00; H10P72/04; H10P72/0402; H10P72/0418; H10P72/0421; C; C23; C23F; C23F4/00; H10P50/00; H10P50/20; H10P50/26; H10P50/264; H10P50/266; H10P50/267; H10P50/69; H10P50/691; H10P50/693; H10P50/694
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
133 words
A method for etching Tungsten on a wafer comprising: (a) transferring a wafer into a process vacuum chamber; (b) applying a pressure to said chamber less than ambient to maintain said chamber at less than ambient; (c) providing fluorine containing gas to a remote plasma chamber separated from said chamber and producing a remote plasma; (d) adding a methane containing gas to said remote plasma chamber; (e) adding a bromine containing gas and a resist selectively enhancement gas to said remote plasma chamber; and (f) applying a radio frequency signal across two electrodes one of which is adjacent to the wafer and causing a plasma to be formed whose dark space is in the vicinity of the surface of the slice; (g) flowing the gas mixture over said wafer disposed within said chamber.
Claim 2
Independent Claim
133 words
A method for etching Tungsten on a wafer comprising: (a) transferring a wafer into a process vacuum chamber; (b) applying a pressure to said chamber less than ambient to maintain said chamber at less than ambient; (c) providing fluorine containing gas to a remote plasma chamber separated from said chamber and producing a remote plasma; (d) adding a methane containing gas to said remote plasma chamber; (e) adding a bromine containing gas and a resist selectively enhancement gas to said remote plasma chamber; and (f) applying a radio frequency signal across two electrodes one of which is adjacent to the wafer and causing a plasma to be formed whose dark space is in the vicinity of the surface of the slice; (g) flowing the gas mixture over said wafer disposed within said chamber.
Claim 3
Independent Claim
64 words
A method for etching tungsten of a water comprising: (a) disposed said wafer in a process chamber at low pressure; (b) generating a remote plasma from a source of fluorine, a source of bromine and a source of hydrocarbon; (c) introducing said remote plasma into said chamber and to a face of said wafer; and (d) generating an in situ plasma within said chamber.
Claim 4
Independent Claim
64 words
A method for etching tungsten of a water comprising: (a) disposed said wafer in a process chamber at low pressure; (b) generating a remote plasma from a source of fluorine, a source of bromine and a source of hydrocarbon; (c) introducing said remote plasma into said chamber and to a face of said wafer; and (d) generating an in situ plasma within said chamber.
Claim 5
Dependent Claim
15 words
The process as set forth in claim 2 wherein said source of hydrocarbon is methane.
Claim 6
Dependent Claim
26 words
The process as set forth in claim 2 wherein the steps of generating said remote plasma, introducing, and generating said in situ plasma are performed concurrently.
Claim 7
Independent Claim
62 words
A method for etching tungsten on a wafer comprising: (a) disposing said wafer in a process chamber; (b) generating free radicals from a source of fluorine, a source of bromine and a source of hydrocarbon; (c) introducing the free radicals into the process chamber and to a face of said wafer; and (d) generating an in situ plasma within the process chamber.
Claim 8
Independent Claim
62 words
A method for etching tungsten on a wafer comprising: (a) disposing said wafer in a process chamber; (b) generating free radicals from a source of fluorine, a source of bromine and a source of hydrocarbon; (c) introducing the free radicals into the process chamber and to a face of said wafer; and (d) generating an in situ plasma within the process chamber.
Claim 9
Dependent Claim
15 words
The process as set forth in claim 5 wherein the source of hydrocarbon is methane.
Claim 10
Dependent Claim
26 words
The process as set forth in claim 5 wherein the steps of generating the free radicals, introducing, and generating the in situ plasma are performed concurrently.
References Cited (Backward Citations)
US3439238A
Cited
US3765763A
Cited
US4306292A
Cited
US4250428A
Cited
US4293249A
Cited
US4465898A
Cited
US4393095A
Cited
US4447469A
Cited
US4439243A
Cited
US4439244A
Cited
US4615905A
Cited
US4493977A
Cited
US4629635A
Cited
US4579609A
Cited
US4609103A
Cited
US4584207A
Cited
US4632057A
Cited
US4673456A
Cited
US4684542A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-06-26 | 1992-12-26 | 1993-06-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-06-26 | 1996-12-26 | 1997-06-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-06-26 | 2000-12-26 | 2001-06-27 | $7700.00 | Window Closed / Lapsed |