US5366590A
Expired / Lapsed
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Dry etching method
Assignee: Sony Corp
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Filing: 1994-03-17
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Granted: 1994-11-22
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Expires: 2014-03-17
Abstract
Abstract Disclosed herein is a method of dry-etching SiO2 layers and Si3N4 layers with high selectivity. The dry etching method employs a fluorocarbon (FC) gas represented by the formula CxFy (where y<x+2) in a dry-etching system capable of generating a high-density plasma having an ion density higher than 1011/cm3. The high-density plasma (such as ECR plasma) promotes the dissociation of gas to a great extent and hence effectively forms CF+ ions even from C6F6 gas. (In the prior-art technology that employs an RF plasma, C6F6 gas merely deposits carbon polymers.) The CF+ ions permits the rapid etching of the SiO2 interlayer insulating film. The FC gas has such a high C/F ratio that it does not form excess F* radicals. Hence it provides high selectivity for the Si3N4 underlying film. If it is used for the etching of the SiO2 layer using the Si3N4 layer as a mask, it provides high selectivity for the mask.
Inventors
- 👤 Shingo Kadomura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 21:22
CPC Classifications
H; H10; H10P; H10P50/00; H10P50/20; H10P50/28; H10P50/282; H10P50/283; H10W; H10W20/00; H10W20/01; H10W20/071; H10W20/081
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
71 words
A dry-etching method which comprises performing etching on a silicon oxide layer formed on a silicon nitride layer with a plasma of etching gas composed mainly of a fluorocarbon compound represented by the formula of C x F y (where y≦x+2, x and y being natural numbers), said plasma being generated in an etching apparatus capable of generating a plasma having an ion density higher than 10 11 /cm 3 .
Claim 2
Dependent Claim
71 words
A dry-etching method which comprises performing etching on a silicon oxide layer formed on a silicon nitride layer with a plasma of etching gas composed mainly of a fluorocarbon compound represented by the formula of C x F y (where y≦x+2, x and y being natural numbers), said plasma being generated in an etching apparatus capable of generating a plasma having an ion density higher than 10 11 /cm 3 .
Claim 3
Dependent Claim
20 words
A dry-etching method as defined in claim 1, wherein the silicon oxide layer has a patterned masking layer formed thereon.
Claim 4
Dependent Claim
24 words
A dry-etching method as defined in claim 1, which further comprises a step of removing the silicon nitride layer after it has been exposed.
Claim 5
Dependent Claim
19 words
A dry-etching method as defined in claim 1, wherein the silicon oxide layer is composed of SiO 2 .
Claim 6
Dependent Claim
21 words
A dry-etching method as defined in claim 1, wherein the silicon nitride layer is composed of Si 3 N 4 .
Claim 7
Dependent Claim
101 words
A dry-etching method which comprises covering a silicon oxide layer with a silicon nitride layer which is patterned such that the area to be etched on the silicon oxide layer is exposed, and performing etching, using the silicon nitride layer as a mask, on the silicon oxide layer with a plasma of etching gas composed mainly of a fluorocarbon compound represented by the formula of C x F y (where y≦x+2, x and y being natural numbers), said plasma being generated in an etching apparatus capable of generating a plasma having an ion density higher than 10 11 /cm 3 .
Claim 8
Dependent Claim
101 words
A dry-etching method which comprises covering a silicon oxide layer with a silicon nitride layer which is patterned such that the area to be etched on the silicon oxide layer is exposed, and performing etching, using the silicon nitride layer as a mask, on the silicon oxide layer with a plasma of etching gas composed mainly of a fluorocarbon compound represented by the formula of C x F y (where y≦x+2, x and y being natural numbers), said plasma being generated in an etching apparatus capable of generating a plasma having an ion density higher than 10 11 /cm 3 .
Claim 9
Dependent Claim
14 words
A dry-etching method as defined in claim 1, wherein the fluorocarbon compound is hexafluorobenzene.
Claim 10
Dependent Claim
14 words
A dry-etching method as defined in claim 6, wherein the fluorocarbon compound is hexafluorobenzene.
References Cited (Backward Citations)
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