US5423945A
Expired / Lapsed
US
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Selectivity for etching an oxide over a nitride
Assignee: Applied Materials Inc
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Filing: 1992-09-08
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Granted: 1995-06-13
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Expires: 2012-09-08
Abstract
Abstract A method of etching an oxide over a nitride with high selectivity comprising plasma etching the oxide with a carbon and fluorine-containing etchant gas in the presence of a scavenger for fluorine, thereby forming a carbon-rich polymer which passivates the nitride. This polymer is inert to the plasma etch gases and thus provides high selectivity to the etch process.
Inventors
- 👤 Jeffrey Marks
- 👤 Kenneth S. Collins
- 👤 Chan-Lon Yang
- 👤 David W. Groechel
- 👤 Peter R. Keswick
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 16:37
CPC Classifications
H; H01; H01J; H01J37/00; H01J37/32; H01J37/32431; H01J37/32798; H01J37/32853; H01J37/32871; H10; H10P; H10P95/00; H01J37/32009; H01J37/32082; H01J37/321; H05; H05H; H05H1/00; H05H1/24; H05H1/46; H10P50/00; H10P50/20; H10P50/28; H10P50/282; H10P50/283; H01J2237/00; H01J2237/32; H01J2237/33; H01J2237/334; H01J2237/3343; H01J2237/3346; H01J2237/3347
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
70 words
A process for etching an oxide layer over a nitride layer in an upper portion of a substrate with high etching selectivity for said oxide, comprising etching said substrate in a plasma derived from a carbon- and fluorine-containing gas and contacted to a scavenger for fluorine aside from said substrate and from said carbon- and fluorine-containing gas and comprising a constituent selected from the group consisting of silicon and carbon.
Claim 2
Dependent Claim
70 words
A process for etching an oxide layer over a nitride layer in an upper portion of a substrate with high etching selectivity for said oxide, comprising etching said substrate in a plasma derived from a carbon- and fluorine-containing gas and contacted to a scavenger for fluorine aside from said substrate and from said carbon- and fluorine-containing gas and comprising a constituent selected from the group consisting of silicon and carbon.
Claim 3
Dependent Claim
12 words
A process according to claim 1 wherein said oxide is silicon oxide.
Claim 4
Dependent Claim
12 words
A process according to claim 1 wherein said nitride is silicon nitride.
Claim 5
Dependent Claim
43 words
A process according to claim 1 wherein said etching step forms a carbon-rich passivating carbon-fluorine polymer over the nitride layer and wherein said carbon-rich polymer contains less than about 40% by weight of fluorine and more than about 50% by weight of carbon.
Claim 6
Dependent Claim
20 words
A process according to claim 1 wherein said scavenger for fluorine is a source of silicon aside from said substrate.
Claim 7
Dependent Claim
19 words
A process according to claim 1 wherein said source of silicon is elemental silicon in contact with the plasma.
Claim 8
Dependent Claim
15 words
A process according to claim 5 wherein said scavenger for fluorine is a silicon-containing gas.
Claim 9
Dependent Claim
23 words
A process according to claim 7 wherein said silicon-containing gas is selected from the group consisting of silane, a substituted silane and tetraethylorthosilicate.
Claim 10
Dependent Claim
18 words
A process according to claim 1 wherein said scavenger for fluorine is graphite in contact with the plasma.
Claim 11
Dependent Claim
20 words
A process according to claim 1 wherein said scavenger for fluorine is disposed above a top surface of said substrate.
Claim 12
Dependent Claim
16 words
A process according to claim 10 wherein said scavenger for fluorine is included within a body.
Claim 13
Dependent Claim
14 words
A process according to claim 11 wherein said body is an electrically controlled electrode.
Claim 14
Dependent Claim
18 words
A process according to claim 11 wherein said body is apart from principal means for creating said plasma.
Claim 15
Dependent Claim
26 words
A process according to claim 11 further comprising inductively inducing said plasma through a coil antenna and electrically biasing said body containing said scavenger for fluorine.
Claim 16
Dependent Claim
34 words
A process according to claim 11 wherein said scavenger for fluorine comprises silicon and further comprising inductively inducing said plasma through a coil antenna and electrically biasing said body containing said scavenger for fluorine.
Claim 17
Dependent Claim
16 words
A process according to claim 1, wherein said scavenger for fluorine is included within a body.
Claim 18
Dependent Claim
13 words
A process according to claim 1 wherein said selectivity is at least 15:1.
Claim 19
Dependent Claim
17 words
A process according to claim 11, wherein said scavenger for fluorine included within said body comprises silicon.
Claim 20
Dependent Claim
19 words
A process according to claim 18, further comprising maintaining said body at a temperature of 150° C. or higher.
Claim 21
Dependent Claim
17 words
A process according to claim 11, wherein said scavenger for fluorine included within said body comprises graphite.
Claim 22
Dependent Claim
49 words
An etch process selective to an oxide over a nitride, comprising the steps of: exposing to a fluorocarbon plasma a substrate comprising an oxide layer over a nitride layer to thereby etch said oxide layer; and contacting said fluorocarbon plasma to a solid source of silicon overlying said substrate.
Claim 23
Dependent Claim
49 words
An etch process selective to an oxide over a nitride, comprising the steps of: exposing to a fluorocarbon plasma a substrate comprising an oxide layer over a nitride layer to thereby etch said oxide layer; and contacting said fluorocarbon plasma to a solid source of silicon overlying said substrate.
Claim 24
Dependent Claim
31 words
An etch process according to claim 20, further comprising: coupling RF energy into said fluorocarbon plasma through a coil antenna; and applying additional RF energy to said solid source of silicon.
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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