US5620615A
Expired / Lapsed
US
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Method of etching or removing W and WSix films
Assignee: Micron Technology Inc
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Filing: 1995-11-30
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Granted: 1997-04-15
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Expires: 2015-11-30
Abstract
Abstract The present invention teaches a method for etching or removing a tungsten (W) film and a tungsten silicide (WSi x ) film during a semiconductor fabrication process, by the steps of: removing any exposed portions of the W or WSi x film by presenting an etchant chemistry comprising NF 3 and HeO 2 to these exposed portions at a temperature ranging from -20° C. to 100° C. The etchant chemistry is also effective for dry cleaning a deposition chamber by removing previously deposited films of W or WSi x .
Inventors
- 👤 David J. Keller
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 09:01
CPC Classifications
C; C23; C23C; C23C16/00; C23C16/44; C23C16/4401; C23C16/4405; C23F; C23F1/00; C23F1/10; C23F1/12; H; H10; H10P; H10P50/00; H10P50/20; H10P50/26; H10P50/264; H10P50/266; H10P50/267; H10P50/268; H10P70/00; H10P70/20; H10P70/27; H10P70/273; Y; Y10; Y10S; Y10S438/00; Y10S438/905
Claims Analysis
Total Claims: 45
Claim 1
Independent Claim
35 words
An etchant chemistry for etching tungsten or tungsten silicide (WSi x ) films during a semiconductor fabrication process, said etchant chemistry having a composition of approximately 85% NF 3 and approximately 15% HeO 2 .
Claim 2
Dependent Claim
35 words
An etchant chemistry for etching tungsten or tungsten silicide (WSi x ) films during a semiconductor fabrication process, said etchant chemistry having a composition of approximately 85% NF 3 and approximately 15% HeO 2 .
Claim 3
Independent Claim
70 words
A method for etching a tungsten (W) film in an enclosed chamber during a semiconductor fabrication process, said method comprising the steps of: presenting an etchant chemistry comprising NF 3 and HeO 2 to exposed portions of said W film at a temperature ranging from -20° C. to 100° C., thereby etching away said exposed portions of said W film and simultaneously etching substantially vertical sidewalls into said W film.
Claim 4
Independent Claim
70 words
A method for etching a tungsten (W) film in an enclosed chamber during a semiconductor fabrication process, said method comprising the steps of: presenting an etchant chemistry comprising NF 3 and HeO 2 to exposed portions of said W film at a temperature ranging from -20° C. to 100° C., thereby etching away said exposed portions of said W film and simultaneously etching substantially vertical sidewalls into said W film.
Claim 5
Dependent Claim
23 words
The method of claim 2, wherein said etchant chemistry has a composition of approximately 85% NF 3 and approximately 15% HeO 2 .
Claim 6
Dependent Claim
57 words
The method as recited in claim 2, 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 F, N and NF x that travel perpendicularly to a self biased cathode of said enclosed chamber, thereby resulting in said substantially vertical sidewalls.
Claim 7
Dependent Claim
34 words
The method as recited in claim 2, further comprising a polysilicon layer lying underneath said W film, said polysilicon layer is etched with the same etchant chemistry comprising NF 3 and HeO 2 .
Claim 8
Dependent Claim
23 words
The method of claim 5, wherein said etchant chemistry has a composition of approximately 85% NF 3 and approximately 15% HeO 2 .
Claim 9
Independent Claim
90 words
A method for etching a tungsten (W) film overlying a polysilicon film in an enclosed chamber during a semiconductor fabrication process, said method comprising the steps of: presenting an etchant chemistry comprising NF 3 and HeO 2 to exposed portions of said W film at a temperature ranging from -20° C. to 100° C., thereby etching away said exposed portions of said W film and simultaneously etching substantially vertical sidewalls into said W film, said etching continues into said polysilicon film, thereby forming a W/polysilicon stack having substantially vertical sidewalls.
Claim 10
Independent Claim
90 words
A method for etching a tungsten (W) film overlying a polysilicon film in an enclosed chamber during a semiconductor fabrication process, said method comprising the steps of: presenting an etchant chemistry comprising NF 3 and HeO 2 to exposed portions of said W film at a temperature ranging from -20° C. to 100° C., thereby etching away said exposed portions of said W film and simultaneously etching substantially vertical sidewalls into said W film, said etching continues into said polysilicon film, thereby forming a W/polysilicon stack having substantially vertical sidewalls.
Claim 11
Dependent Claim
23 words
The method of claim 7, wherein said etchant chemistry has a composition of approximately 85% NF 3 and approximately 15% HeO 2 .
Claim 12
Dependent Claim
28 words
The method as recited in claim 7, wherein said polysilicon film contains a dopant concentration comprising a dopant selected from the group consisting of phosphorus, arsenic and boron.
Claim 13
Dependent Claim
15 words
The method as recited in claim 7, wherein chlorine is added to said etchant chemistry.
Claim 14
Dependent Claim
30 words
The method as recited in claim 10, wherein said etchant chemistry has a composition of approximately 75% NF 3 , approximately 12.5% HeO 2 and approximately 12.5% Cl 2 .
Claim 15
Dependent Claim
18 words
The method as recited in claim 7, wherein a bromine containing compound is added to said etchant chemistry.
Claim 16
Dependent Claim
28 words
The method as recited in claim 12, wherein said etchant chemistry has a composition of approximately 75% NF 3 , approximately 12.5% HeO 2 and approximately 12.5% HBr.
Claim 17
Dependent Claim
18 words
The method as recited in claim 7, wherein iodine (I 2 ) is added to said etchant chemistry.
Claim 18
Dependent Claim
30 words
The method as recited in claim 14, wherein said etchant chemistry has a composition of approximately 75% NF 3 , approximately 12.5% HeO 2 and approximately 12.5% I 2 .
Claim 19
Dependent Claim
57 words
The method as recited in claim 7, 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 perpendicularly to a self biased cathode of said enclosed chamber, thereby resulting in said substantially vertical sidewalls.
Claim 20
Dependent Claim
18 words
The method as recited in claim 7, wherein said semiconductor fabrication process is a logic device fabrication process.
Claim 21
Dependent Claim
18 words
The method as recited in claim 7, wherein said semiconductor fabrication process is a microprocessor device fabrication process.
Claim 22
Dependent Claim
18 words
The method as recited in claim 7, wherein said semiconductor fabrication process is a memory device fabrication process.
Claim 23
Dependent Claim
23 words
The method as recited in claim 19, wherein said memory device fabrication process is a dynamic random access memory (DRAM) device fabrication process.
Claim 24
Dependent Claim
23 words
The method as recited in claim 19, wherein said memory device fabrication process is a static random access memory (SRAM) device fabrication process.
Claim 25
Dependent Claim
20 words
The method as recited in claim 19, wherein said memory device fabrication process is a flash memory device fabrication process.
Claim 26
Independent Claim
65 words
A method for removing a tungsten silicide (WSi x ) film from the walls of an enclosed deposition chamber during a semiconductor fabrication process, said method comprising the step of: presenting an etchant chemistry comprising NF 3 and HeO 2 to said chamber at a temperature ranging from -20° C. to 100° C., thereby etching away any WSi x film formed on said chamber walls.
Claim 27
Independent Claim
65 words
A method for removing a tungsten silicide (WSi x ) film from the walls of an enclosed deposition chamber during a semiconductor fabrication process, said method comprising the step of: presenting an etchant chemistry comprising NF 3 and HeO 2 to said chamber at a temperature ranging from -20° C. to 100° C., thereby etching away any WSi x film formed on said chamber walls.
Claim 28
Dependent Claim
23 words
The method of claim 23, wherein said etchant chemistry has a composition of approximately 85% NF 3 and approximately 15% HeO 2 .
Claim 29
Dependent Claim
50 words
The method as recited in claim 23, 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 F, N and NF x that travel perpendicularly to a self biased cathode of said enclosed chamber.
Claim 30
Dependent Claim
18 words
The method as recited in claim 23, wherein said semiconductor fabrication process is a logic device fabrication process.
Claim 31
Dependent Claim
18 words
The method as recited in claim 23, wherein said semiconductor fabrication process is a microprocessor device fabrication process.
Claim 32
Dependent Claim
18 words
The method as recited in claim 23, wherein said semiconductor fabrication process is a memory device fabrication process.
Claim 33
Dependent Claim
23 words
The method as recited in claim 28, wherein said memory device fabrication process is a dynamic random access memory (DRAM) device fabrication process.
Claim 34
Dependent Claim
23 words
The method as recited in claim 28, wherein said memory device fabrication process is a static random access memory (SRAM) device fabrication process.
Claim 35
Dependent Claim
20 words
The method as recited in claim 28, wherein said memory device fabrication process is a flash memory device fabrication process.
Claim 36
Independent Claim
61 words
A method for removing a tungsten (W) film from the walls of an enclosed deposition chamber during a semiconductor fabrication process, said method comprising the step of: presenting an etchant chemistry comprising NF 3 and HeO 2 to said chamber at a temperature ranging from -20° C. to 100° C., thereby etching away any W film formed on said chamber walls.
Claim 37
Independent Claim
61 words
A method for removing a tungsten (W) film from the walls of an enclosed deposition chamber during a semiconductor fabrication process, said method comprising the step of: presenting an etchant chemistry comprising NF 3 and HeO 2 to said chamber at a temperature ranging from -20° C. to 100° C., thereby etching away any W film formed on said chamber walls.
Claim 38
Dependent Claim
23 words
The method of claim 32, wherein said etchant chemistry has a composition of approximately 85% NF 3 and approximately 15% HeO 2 .
Claim 39
Dependent Claim
50 words
The method as recited in claim 32, 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 F, N and NF x that travel perpendicularly to a self biased cathode of said enclosed chamber.
Claim 40
Dependent Claim
18 words
The method as recited in claim 32, wherein said semiconductor fabrication process is a logic device fabrication process.
Claim 41
Dependent Claim
18 words
The method as recited in claim 32, wherein said semiconductor fabrication process is a microprocessor device fabrication process.
Claim 42
Dependent Claim
18 words
The method as recited in claim 32, wherein said semiconductor fabrication process is a memory device fabrication process.
Claim 43
Dependent Claim
23 words
The method as recited in claim 37, wherein said memory device fabrication process is a dynamic random access memory (DRAM) device fabrication process.
Claim 44
Dependent Claim
23 words
The method as recited in claim 37, wherein said memory device fabrication process is a static random access memory (SRAM) device fabrication process.
Claim 45
Dependent Claim
20 words
The method as recited in claim 37, wherein said memory device fabrication process is a flash memory device fabrication process.
References Cited (Backward Citations)
US5015330A
Cited
US5413670A
Cited
US5387312A
Cited
US5382316A
Cited
US5413669A
Cited
US5492597A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 2000-04-14 | 2000-10-14 | 2001-04-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-04-14 | 2004-10-14 | 2005-04-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-04-14 | 2008-10-14 | 2009-04-15 | $7700.00 | Window Closed / Lapsed |