US5492597A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of etching WSix films
Assignee: Micron Technology Inc
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Filing: 1994-05-13
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Granted: 1996-02-20
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Expires: 2014-05-13
Abstract
Abstract The present invention teaches a method for etching a tungsten silicide (WSi x ) film overlying a polysilicon film in an enclosed chamber during a semiconductor fabrication process, by the steps of: providing a patterned mask overlying the WSi x film thereby providing exposed portions of the WSi x film; presenting an etchant chemistry comprising NF 3 and HeO 2 to the exposed portions of the WSi x film at a temperature ranging from -20° C. to 100° C., thereby etching away the exposed portions of the WSi x film and simultaneously etching substantially vertical sidewalls in the WSi x film, the etching continues into the polysilicon film, thereby forming a WSi x /polysilicon stack having substantially vertical sidewalls.
Inventors
- 👤 David J. Keller
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 20:10
CPC Classifications
H; H10; H10P; H10P70/00; H10P70/20; H10P70/27; H10P70/273; C; C23; C23C; C23C16/00; C23C16/44; C23C16/4401; C23C16/4405; C23F; C23F1/00; C23F1/10; C23F1/12; H10P50/00; H10P50/20; H10P50/26; H10P50/264; H10P50/266; H10P50/267; H10P50/268
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
95 words
A method for etching a tungsten silicide (WSi x ) film in an enclosed chamber during a semiconductor fabrication process, said method comprising the steps of: providing a patterned mask overlying said WSi x film thereby providing exposed portions of said WSi x film; presenting an etchant chemistry comprising NF 3 and HeO 2 to said exposed portions of the WSi x film at a temperature ranging from -20° C. to 100° C., thereby etching away said exposed portions of said WSi x film and simultaneously etching substantially vertical sidewalls in said WSi x film.
Claim 2
Independent Claim
95 words
A method for etching a tungsten silicide (WSi x ) film in an enclosed chamber during a semiconductor fabrication process, said method comprising the steps of: providing a patterned mask overlying said WSi x film thereby providing exposed portions of said WSi x film; presenting an etchant chemistry comprising NF 3 and HeO 2 to said exposed portions of the WSi x film at a temperature ranging from -20° C. to 100° C., thereby etching away said exposed portions of said WSi x film and simultaneously etching substantially vertical sidewalls in said WSi x film.
Claim 3
Dependent Claim
56 words
The method as recited in claim 1, wherein said presentation of said etchant chemistry forms an NF3 plasma thereby creating positive ions comprising fluorine (F) and nitrogen (N) in the form of F, N and NF x that travel perpendicular to a self biased cathode of said enclosed chamber, thereby resulting in said substantially vertical sidewalls.
Claim 4
Dependent Claim
35 words
The method as recited in claim 1, further comprising a polysilicon layer lying underneath said WSi x film, said polysilicon layer is etched with the same etchant chemistry comprising NF 3 and HeO 2 .
Claim 5
Independent Claim
117 words
A method for etching a tungsten silicide (WSi x ) film overlying a polysilicon film in an enclosed chamber during a semiconductor fabrication process, said method comprising the steps of: providing a patterned mask overlying said WSi x film thereby providing exposed portions of said WSi x film; presenting an etchant chemistry comprising NF 3 and HeO 2 to said exposed portions of the WSi x film at a temperature ranging from -20° C. to 100° C., thereby etching away said exposed portions of said WSi x film and simultaneously etching substantially vertical sidewalls in said WSi x film, said etching continues into said polysilicon film, thereby forming a WSi x /polysilicon stack having substantially vertical sidewalls.
Claim 6
Independent Claim
117 words
A method for etching a tungsten silicide (WSi x ) film overlying a polysilicon film in an enclosed chamber during a semiconductor fabrication process, said method comprising the steps of: providing a patterned mask overlying said WSi x film thereby providing exposed portions of said WSi x film; presenting an etchant chemistry comprising NF 3 and HeO 2 to said exposed portions of the WSi x film at a temperature ranging from -20° C. to 100° C., thereby etching away said exposed portions of said WSi x film and simultaneously etching substantially vertical sidewalls in said WSi x film, said etching continues into said polysilicon film, thereby forming a WSi x /polysilicon stack having substantially vertical sidewalls.
Claim 7
Dependent Claim
20 words
The method as recited in claim 4, further comprising the deposition of a dielectric film over said WSi x film.
Claim 8
Dependent Claim
14 words
The method as recited in claim 5, wherein said dielectric film is silicon nitride.
Claim 9
Dependent Claim
14 words
The method as recited in claim 5, wherein said dielectric film is silicon dioxide.
Claim 10
Dependent Claim
28 words
The method as recited in claim 4, wherein said polysilicon film contains a dopant concentration comprising a dopant selected from the group consisting of phosphorus, arsenic and boron.
Claim 11
Dependent Claim
18 words
The method as recited in claim 8, wherein a chlorine containing compound is added to said etchant chemistry.
Claim 12
Dependent Claim
18 words
The method as recited in claim 8, wherein a bromine containing compound is added to said etchant chemistry.
Claim 13
Dependent Claim
18 words
The method as recited in claim 8, wherein an iodine containing compound is added to said etchant chemistry.
Claim 14
Dependent Claim
57 words
The method as recited in claim 4, wherein said presentation of said etchant chemistry forms an NF 3 plasma thereby creating positive ions comprising fluorine (F) and nitrogen (N) in the form of N, F and NF x that travel perpendicular to a self biased cathode of said enclosed chamber, thereby resulting in said substantially vertical sidewalls.
Claim 15
Dependent Claim
16 words
The method as recited in claim 4, wherein said WSi x /polysilicon stack forms a wordline.
Claim 16
Dependent Claim
16 words
The method as recited in claim 4, wherein said WSi x /polysilicon stack forms a digitline.
Claim 17
Dependent Claim
18 words
The method as recited in claim 4, wherein said semiconductor fabrication process is a logic device fabrication process.
Claim 18
Dependent Claim
18 words
The method as recited in claim 4, wherein said semiconductor fabrication process is a microprocessor device fabrication process.
Claim 19
Dependent Claim
17 words
The method as recited in claim 4, wherein said semiconductor/fabrication process is a memory device fabrication process.
Claim 20
Dependent Claim
23 words
The method as recited in claim 17, wherein said memory device fabrication process is a dynamic random access memory (DRAM) device fabrication process.
Claim 21
Dependent Claim
23 words
The method as recited in claim 17, wherein said memory device fabrication process is a static random access memory (SRAM) device fabrication process.
Claim 22
Dependent Claim
20 words
The method as recited in claim 17, wherein said memory device fabrication process is a flash memory device fabrication process.
References Cited (Backward Citations)
US5387312A
Cited
US5382316A
Cited
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