Patent US5874363A successfully refreshed from Google Patents.
US5874363A
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Polycide etching with HCL and chlorine
Assignee: Qimonda AG
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Filing: 1996-05-13
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Granted: 1999-02-23
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Expires: 2016-05-13
Abstract
Abstract Metal silicide is removed at a faster rate than polysilicon in dry etching of metal silicide/polysilicon composites with an etching gas made from HCl and Cl2 at a volumetric flowrate ratio of HCl:Cl2 within the range of 3:1 to 5:1.
Inventors
- 👤 Peter D. Hoh
- 👤 Tokuhisa Ohiwa
- 👤 Virinder Grewal
- 👤 Bruno Spuler
- 👤 Waldemar Kocon
- 👤 Guadalupe Wiltshire
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 09:14
CPC Classifications
H; H10; H10P; H10P50/00; H10P50/20; H10P50/26; H10P50/264; H10P50/266; H10P50/267; H10P50/268
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
74 words
A process for etching a metal silicide layer at a rate faster than a polysilicon layer in a metal silicide/polysilicon composite by an etching process that comprises: contacting said metal silicide layer with a plasma free of BCl 3 made from a flowing gas mixture of HCl and Cl 2 exhibiting a HCl:Cl 2 flowrate ratio within the range of 3:1 to 5:1, said flowing gas consisting essentially of HCl and Cl 2 .
Claim 2
Dependent Claim
74 words
A process for etching a metal silicide layer at a rate faster than a polysilicon layer in a metal silicide/polysilicon composite by an etching process that comprises: contacting said metal silicide layer with a plasma free of BCl 3 made from a flowing gas mixture of HCl and Cl 2 exhibiting a HCl:Cl 2 flowrate ratio within the range of 3:1 to 5:1, said flowing gas consisting essentially of HCl and Cl 2 .
Claim 3
Dependent Claim
14 words
A process as in claim 1 wherein said plasma is generated by inductive coupling.
Claim 4
Dependent Claim
19 words
A process as in claim 2 wherein a temperature of said plasma is within the range of 20°-60° C.
Claim 5
Dependent Claim
19 words
A process as in claim 3 wherein a temperature of said plasma is within the range of 40°-60° C.
Claim 6
Dependent Claim
16 words
A process as in claim 1 wherein said flowrate ratio is within the range of 3:1-4:1.
Claim 7
Dependent Claim
80 words
A process for etching a metal silicide layer at a rate faster than a polysilicon layer in a metal silicide/polysilicon composite by an etching process that comprises: contacting said metal silicide layer with a stream of reactive ions made from a flowing gas mixture of HCl and Cl 2 exhibiting a HCl:Cl 2 flowrate ratio within the range of 3:1-5:1, at a temperature within the range from 40°-60° C., said flowing gas consisting essentially of HCl and Cl 2 .
Claim 8
Dependent Claim
80 words
A process for etching a metal silicide layer at a rate faster than a polysilicon layer in a metal silicide/polysilicon composite by an etching process that comprises: contacting said metal silicide layer with a stream of reactive ions made from a flowing gas mixture of HCl and Cl 2 exhibiting a HCl:Cl 2 flowrate ratio within the range of 3:1-5:1, at a temperature within the range from 40°-60° C., said flowing gas consisting essentially of HCl and Cl 2 .
Claim 9
Dependent Claim
120 words
A process for etching a masked metal silicide/polysilicon composite by the steps comprising: contacting said composite with a plasma free of BCl 3 or reactive ion stream made from a flowing gas comprising NF 3 , HCl, and Cl 2 for a time sufficient to remove native oxide from said composite; discontinuing flow of said NF 3 , and etching said metal silicide layer at a rate faster than said polysilicon by contacting said composite with a plasma or reactive ion stream made from a flowing gas comprising HCl and Cl 2 in a HCl:Cl 2 flowrate ratio within the range of 3:1 to 5:1 for a time sufficient to remove said metal silicide from unmasked areas of said composite.
Claim 10
Dependent Claim
120 words
A process for etching a masked metal silicide/polysilicon composite by the steps comprising: contacting said composite with a plasma free of BCl 3 or reactive ion stream made from a flowing gas comprising NF 3 , HCl, and Cl 2 for a time sufficient to remove native oxide from said composite; discontinuing flow of said NF 3 , and etching said metal silicide layer at a rate faster than said polysilicon by contacting said composite with a plasma or reactive ion stream made from a flowing gas comprising HCl and Cl 2 in a HCl:Cl 2 flowrate ratio within the range of 3:1 to 5:1 for a time sufficient to remove said metal silicide from unmasked areas of said composite.
Claim 11
Dependent Claim
31 words
A process as in claim 7 further comprising: changing said HCl:Cl 2 flowrate ratio to a value of less than 3 to etch said polysilicon after etching said metal silicide layer.
Claim 12
Dependent Claim
26 words
A process as in claim 7 wherein said flowing gas consists essentially of HCl and Cl 2 in said step of etching said metal silicide layer.
Claim 13
Dependent Claim
28 words
A process as in claim 7, wherein said flowing gas consists essentially of HCl, Cl 2 , and oxygen in said step of etching said metal silicide layer.
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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) | 2002-02-22 | 2002-08-24 | 2003-02-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-02-22 | 2006-08-24 | 2007-02-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2010-02-22 | 2010-08-24 | 2011-02-23 | $7700.00 | Window Closed / Lapsed |