Patent US4838990A successfully refreshed from Google Patents.
US4838990A
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Method for plasma etching tungsten
Assignee: Texas Instruments Inc
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Filing: 1987-07-16
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Granted: 1989-06-13
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Expires: 2007-07-16
Abstract
Abstract A process wherein 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 fluorosilane (e.g. SiF 4 ), plus a bromine source (such as HBr), plus a weak oxygen source such as carbon monoxide. This chemistry provides anisotropic high rate fluoro-etching with good selectivity to photoresist.
Inventors
- 👤 Rhett B. Jucha
- 👤 Cecil J. Davis
- 👤 John I. Jones
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 02:49
CPC Classifications
H; H10; H10P; H10P72/00; H10P72/30; H10P72/33; H10P72/3306; C; C23; C23C; C23C16/00; C23C16/44; C23C16/50; C23C16/517; C23F; C23F4/00; H01; H01J; H01J37/00; H01J37/32; H01J37/32009; H01J37/32321; H01J37/32339; H01J37/32431; H01J37/32733; H01J37/32743; H01J37/32788; H10P50/00; H10P50/20; H10P50/26; H10P50/264; H10P50/266; H10P50/267; H10P72/04; H10P72/0402; H10P72/0418; H10P72/0421; H10P72/0431; H10P72/0436; H10P72/3308; H01J2237/00; H01J2237/02; H01J2237/022; H01J2237/18; H01J2237/184; H01J2237/32; H01J2237/33; H01J2237/334; H01J2237/3343; H01J2237/3345
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
135 words
A method for etching Tungsten on a wafer comprising: (a) transferring a wafer into a vacuum processing 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 very weak oxygen source gas to said remote plasma chamber; (e) adding a bromine containing gas and a resist selectivity enhancement has to said remote plasma chamber; (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; and (g) flowing the gas mixture over said wafer disposed within said chamber.
Claim 2
Independent Claim
135 words
A method for etching Tungsten on a wafer comprising: (a) transferring a wafer into a vacuum processing 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 very weak oxygen source gas to said remote plasma chamber; (e) adding a bromine containing gas and a resist selectivity enhancement has to said remote plasma chamber; (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; and (g) flowing the gas mixture over said wafer disposed within said chamber.
Claim 3
Independent Claim
64 words
A method for etching tungsten on a wafer comprising: (a) disposing said wafer into a process chamber at low pressure; (b) generating a remote plasma form a source of fluorine, a weak source of oxygen, and a source of bromide; (c) introducing said remote plasma into said chamber 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 on a wafer comprising: (a) disposing said wafer into a process chamber at low pressure; (b) generating a remote plasma form a source of fluorine, a weak source of oxygen, and a source of bromide; (c) introducing said remote plasma into said chamber to a face of said wafer; and (d) generating an in situ plasma within said chamber.
Claim 5
Dependent Claim
19 words
The process as set forth in claim 2 wherein said step of generating said remote plasma includes a fluorosilane.
Claim 6
Dependent Claim
23 words
The process as set forth in claim 1 wherein the steps of generating free radicals and an in situ plasma are controlled singly.
Claim 7
Dependent Claim
27 words
The process as set forth in claim 1 wherein the steps of generating free radicals and an in situ plasma are controlled in combination with each other.
Claim 8
Dependent Claim
23 words
The process as set forth in claim 2 wherein the steps of generating free radicals and an in situ plasma are controlled singly.
Claim 9
Dependent Claim
27 words
The process as set forth in claim 2 wherein the steps of generating free radicals and an in situ plasma are controlled in combination with each other.
Claim 10
Independent Claim
81 words
A method for etching Tungsten on a wafer in a process chamber, comprising the steps of: (a) generating free radicals from a fluorine containing gas, very weak oxygen source, a bromine containing gas and a resist selectivity enhancement gas to plasma generator remote from the process chamber; (b) introducing the free radicals to the process chamber and to a face of the wafer to be porocessed; and (c) generating an in situ plasma from the free radicals in the process chamber.
Claim 11
Independent Claim
81 words
A method for etching Tungsten on a wafer in a process chamber, comprising the steps of: (a) generating free radicals from a fluorine containing gas, very weak oxygen source, a bromine containing gas and a resist selectivity enhancement gas to plasma generator remote from the process chamber; (b) introducing the free radicals to the process chamber and to a face of the wafer to be porocessed; and (c) generating an in situ plasma from the free radicals in the process chamber.
Claim 12
Dependent Claim
23 words
The process as set forth in claim 8 wherein the steps of generating free radicals and an in situ plasma are controlled singly.
Claim 13
Dependent Claim
27 words
The process as set forth in claim 8 wherein the steps of generating free radicals and an in situ plasma are controlled in combination with each other.
Claim 14
Dependent Claim
15 words
The process as set forth in claim 8 wherein the fluorine containing gas is fluorosilane.
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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) | 1992-06-12 | 1992-12-12 | 1993-06-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-06-12 | 1996-12-12 | 1997-06-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-06-12 | 2000-12-12 | 2001-06-13 | $7700.00 | Window Closed / Lapsed |