US5397431A
Expired / Lapsed
US
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Dry etching method
Assignee: Sony Corp
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Filing: 1993-07-22
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Granted: 1995-03-14
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Expires: 2013-07-22
Abstract
Abstract A dry etching method for etching an SiO2 interlayer insulation film 4 formed on an Si2N4 underlying film 3 using an S2F2/N2 mixed gas. While the etching proceeds by way of F* and SFx+yielded from S2F2, atoms yielded similarly from S2F2 and N atoms yielded from N2 are combined with each other, thus yielding sulfur nitride based compounds such as polythiazyl (SN)x to be deposited on pattern sidewall surfaces. When the Si3N4 underlying film 3 is exposed, N atoms in the film and S atoms in a plasma are combined to form (SN)x. These (SN)x in a gaseous phase and on solid surface protect wafer surfaces, improving selectivity. It is also possible to etch the SiO2 interlayer insulation film with an Si3N4 mask, achieving high selectivity to the mask.
Inventors
- 👤 Shingo Kadomura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 04:27
CPC Classifications
H; H10; H10P; H10P50/00; H10P50/20; H10P50/28; H10P50/282; H10P50/283
Claims Analysis
Total Claims: 28
Claim 1
Independent Claim
86 words
A dry etching method for selectively etching a silicon oxide based material layer formed on a silicon nitride based material layer, comprising carrying out a plasma etching using an etching gas containing at least one kind of sulfur fluoride selected from the group consisting of S 2 F 2 , SF 2 , SF 4 and S 2 F 10 , and a nitrogen based gas, and while plasma etching depositing a sulfur nitride based compound on a surface portion of the silicon oxide based material.
Claim 2
Dependent Claim
86 words
A dry etching method for selectively etching a silicon oxide based material layer formed on a silicon nitride based material layer, comprising carrying out a plasma etching using an etching gas containing at least one kind of sulfur fluoride selected from the group consisting of S 2 F 2 , SF 2 , SF 4 and S 2 F 10 , and a nitrogen based gas, and while plasma etching depositing a sulfur nitride based compound on a surface portion of the silicon oxide based material.
Claim 3
Dependent Claim
41 words
The dry etching method as claimed in claim 1 wherein the nitrogen based gas is selected from the group consisting of N 2 , NF 3 , NCl 3 , NBr 3 , NO 2 and N 2 H 2 .
Claim 4
Dependent Claim
37 words
The dry etching method as claimed in claim 1 wherein an H based gas selected from the group consisting of H 2 , H 2 S and a silane based gas is added to the etching gas.
Claim 5
Dependent Claim
22 words
The dry etching method as claimed in claim 1 wherein the sulfur nitride based compound is polythiazyl expressed by (SN) n .
Claim 6
Dependent Claim
22 words
The dry etching method as claimed in claim 1 wherein deposited sulfur nitride based compound is removed by ashing after the etching.
Claim 7
Dependent Claim
25 words
The dry etching method as claimed in claim 1 wherein deposited sulfur nitride based compound is removed by sublimation due to heating after the etching.
Claim 8
Dependent Claim
151 words
A dry plasma etching method for selectively etching a silicon oxide based material layer formed on a silicon nitride based material layer, comprising a just etching process, using an etching gas containing at least one kind of sulfur fluoride selected from the group consisting of S 2 F 2 , SF 2 , SF 4 and S 2 F 10 , and plasma etching a silicon oxide material layer substantially to thickness thereof while yielding depositable sulfur in an etching reaction system, and an overetching process, using an etching gas containing at least one kind of sulfur fluoride selected from the group consisting of S 2 F 2 , SF 2 , SF 4 and S 2 F 10 , and a nitrogen based compound, and plasma etching a remaining portion of the silicon oxide based material layer while yielding a depositable sulfur nitride based compound in an etching reaction system.
Claim 9
Dependent Claim
151 words
A dry plasma etching method for selectively etching a silicon oxide based material layer formed on a silicon nitride based material layer, comprising a just etching process, using an etching gas containing at least one kind of sulfur fluoride selected from the group consisting of S 2 F 2 , SF 2 , SF 4 and S 2 F 10 , and plasma etching a silicon oxide material layer substantially to thickness thereof while yielding depositable sulfur in an etching reaction system, and an overetching process, using an etching gas containing at least one kind of sulfur fluoride selected from the group consisting of S 2 F 2 , SF 2 , SF 4 and S 2 F 10 , and a nitrogen based compound, and plasma etching a remaining portion of the silicon oxide based material layer while yielding a depositable sulfur nitride based compound in an etching reaction system.
Claim 10
Dependent Claim
41 words
The dry etching method as claimed in claim 7 wherein the nitrogen based compound is selected from the group consisting of N 2 , NF 3 , CNl 3 , NBr 3 , NO 2 and N 2 H 2 .
Claim 11
Dependent Claim
37 words
The dry etching method as claimed in claim 7 wherein an H based gas selected from the group consisting of H 2 , H 2 S and a silane based gas is added to the etching gas.
Claim 12
Dependent Claim
22 words
The dry etching method as claimed in claim 7 wherein the sulfur nitride based compound is polythiazyl expressed by (SN) n .
Claim 13
Dependent Claim
22 words
The dry etching method as claimed in claim 7 wherein deposited sulfur nitride based compound is removed by ashing after the etching.
Claim 14
Dependent Claim
25 words
The dry etching method as claimed in claim 7 wherein deposited sulfur nitride based compound is removed by sublimation due to heating after the etching.
Claim 15
Dependent Claim
101 words
A dry etching method for selectively etching a silicon oxide based material layer formed on a substrate, comprising providing a patterned layer of sulfur nitride based compound on the silicon oxide based material layer, carrying out a plasma etching using an etching gas containing at least one kind of sulfur fluoride selected from the group consisting of S 2 F 2 , SF 2 , SF 4 and S 2 F 10 , and a nitrogen based gas, and while plasma etching depositing a sulfur nitride based compound on exposed portions of the silicon oxide based material layer and the substrate.
Claim 16
Dependent Claim
101 words
A dry etching method for selectively etching a silicon oxide based material layer formed on a substrate, comprising providing a patterned layer of sulfur nitride based compound on the silicon oxide based material layer, carrying out a plasma etching using an etching gas containing at least one kind of sulfur fluoride selected from the group consisting of S 2 F 2 , SF 2 , SF 4 and S 2 F 10 , and a nitrogen based gas, and while plasma etching depositing a sulfur nitride based compound on exposed portions of the silicon oxide based material layer and the substrate.
Claim 17
Dependent Claim
42 words
The dry etching method as claimed in claim 13 wherein the nitrogen based gas compound is selected from the group consisting of N 2 , NF 3 , NCl 3 , NBr 3 , NO 2 and N 2 H 2 .
Claim 18
Dependent Claim
37 words
The dry etching method as claimed in claim 13 wherein an H based gas selected from the group consisting of H 2 , N 2 S and a silane based gas is added to the etching gas.
Claim 19
Dependent Claim
22 words
The dry etching method as claimed in claim 13 wherein the sulfur nitrogen based compound is polythiazyl expressed by (SN) n .
Claim 20
Dependent Claim
22 words
The dry etching method as claimed in claim 13 wherein deposited sulfur nitride based compound is removed by ashing after the etching.
Claim 21
Dependent Claim
25 words
The dry etching method as claimed in claim 13 wherein deposited sulfur nitrogen based compound is removed by sublimation due to heating after the etching.
Claim 22
Dependent Claim
165 words
A dry plasma etching method for etching a silicon oxide based material layer with a sulfur nitride based compound layer selectively formed thereon as a mask, comprising a just etching process, using an etching gas containing at least one kind of sulfur fluoride selected from the group consisting of S 2 F 2 , SF 2 , SF 4 and S 2 F 10 , and a nitrogen based compound, and plasma etching the silicon oxide based material layer substantially to thickness thereof while yielding depositable sulfur and sulfur nitride based compound in an etching reaction system, and an overetching process, using an etching gas containing at least one kind of sulfur fluoride selected from the group consisting of S 2 F 2 , SF 2 , SF 4 and S 2 F 10 , and a nitrogen based compound, and plasma etching a remaining portion of the silicon oxide material layer while yielding a depositable sulfur nitride based compound in an etching reaction system.
Claim 23
Dependent Claim
165 words
A dry plasma etching method for etching a silicon oxide based material layer with a sulfur nitride based compound layer selectively formed thereon as a mask, comprising a just etching process, using an etching gas containing at least one kind of sulfur fluoride selected from the group consisting of S 2 F 2 , SF 2 , SF 4 and S 2 F 10 , and a nitrogen based compound, and plasma etching the silicon oxide based material layer substantially to thickness thereof while yielding depositable sulfur and sulfur nitride based compound in an etching reaction system, and an overetching process, using an etching gas containing at least one kind of sulfur fluoride selected from the group consisting of S 2 F 2 , SF 2 , SF 4 and S 2 F 10 , and a nitrogen based compound, and plasma etching a remaining portion of the silicon oxide material layer while yielding a depositable sulfur nitride based compound in an etching reaction system.
Claim 24
Dependent Claim
41 words
The dry etching method as claimed in claim 19 wherein the nitrogen based compound is selected from the group consisting of N 2 , NF 3 , NCl 3 , NBr 3 , NO 2 and N 2 H 2 .
Claim 25
Dependent Claim
37 words
The dry etching method as claimed in claim 19 wherein an H based gas selected from the group consisting of H 2 , H 2 S and a silane based gas is added to the etching gas.
Claim 26
Dependent Claim
22 words
The dry etching method as claimed in claim 19 wherein the sulfur nitride based compound is polythiazyl expressed by (SN) n .
Claim 27
Dependent Claim
22 words
The dry etching method as claimed in claim 19 wherein deposited sulfur nitride based compound is removed by ashing after the etching.
Claim 28
Dependent Claim
25 words
The dry etching method as claimed in claim 19 wherein deposited sulfur nitride based compound is removed by sublimation due to heating after the etching.
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