US5328558A
Expired / Lapsed
US
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Method for etching an SiO2 film
Assignee: Tokyo Electron Ltd
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Filing: 1993-03-25
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Granted: 1994-07-12
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Expires: 2013-03-25
Abstract
Abstract An NF 3 /H 2 mixture as a feed gas for an etchant for etching an SiO 2 film on an silicon wafer is used with a 1 : 160 NF 3 /H 2 mixed ratio. The mixture is made into plasma, and activated species of fluorine, hydrogen and nitrogen are supplied downstream to allow the species to be adsorbed in and on the SiO 2 film. The NF 3 /H 2 mixed ratio of the mixture is so set as not to effect the etching of the SiO 2 film under a chemical action. Then the adsorbed activated species are irradiated with Ar low energy ions so that the activated species are excited and etch the SiO 2 film. During etching, the semiconductor wafer is maintained to about -100° C. Less damage is caused to the silicon wafer and etching can be made in a high selection ratio.
Inventors
- 👤 Kouhei Kawamura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 09:11
CPC Classifications
H; H10; H10P; H10P50/00; H10P50/20; H10P50/28; H10P50/282; H10P50/283; Y; Y10; Y10S; Y10S148/00; Y10S148/017
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
105 words
A method for etching an SiO 2 film on a semiconductor wafer, comprising: positioning the wafer in a process chamber; evacuating the process chamber to a vacuum state; supplying activated species of fluorine and hydrogen in a mixed form onto the wafer to allow the species to be adsorbed in and on the SiO 2 film, a mixed ratio of the activated species being so set as not to effect etching of the SiO 2 film under a chemical action; and irradiating the adsorbed activated species with low energy ions of inert gas atoms to excite the activated species and etching the SiO 2 film.
Claim 2
Independent Claim
105 words
A method for etching an SiO 2 film on a semiconductor wafer, comprising: positioning the wafer in a process chamber; evacuating the process chamber to a vacuum state; supplying activated species of fluorine and hydrogen in a mixed form onto the wafer to allow the species to be adsorbed in and on the SiO 2 film, a mixed ratio of the activated species being so set as not to effect etching of the SiO 2 film under a chemical action; and irradiating the adsorbed activated species with low energy ions of inert gas atoms to excite the activated species and etching the SiO 2 film.
Claim 3
Dependent Claim
24 words
The method according to claim 1, further comprising the step of maintaining the semiconductor wafer at a temperature less than 0° C. during etching.
Claim 4
Dependent Claim
29 words
The method according to claim 2, wherein the supply of the activated species and exposure of these species with the low energy ions are repeated a plurality of times.
Claim 5
Dependent Claim
56 words
The method according to claim 3, wherein the activated species of fluorine and hydrogen are generated by making a mixture of a first gas containing fluorine and second gas containing hydrogen into plasma outside the process chamber and the plasma is introduced into the process chamber so that the activated species are supplied onto the wafer.
Claim 6
Dependent Claim
25 words
The method according to claim 3, wherein activated species of nitrogen, together with the activated species of fluorine and hydrogen, are supplied onto the wafer.
Claim 7
Dependent Claim
62 words
The method according to claim 5 wherein the activated species of fluorine, hydrogen and nitrogen are generated by making a mixture of a first gas containing fluorine, second gas containing hydrogen and third gas containing nitrogen into plasma outside the process chamber and then the plasma is introduced into the process chamber so that the activated species are supplied onto the wafer.
Claim 8
Dependent Claim
39 words
The method according to claim 5, wherein the first and their gases are composed of NF 3 and second gas is composed of H 2 and an H 2 /NF 3 mixed ratio of the mixture is above 160.
Claim 9
Independent Claim
134 words
A method for etching an SiO 2 film on a semiconductor wafer, comprising the steps of: positioning the semiconductor wafer in a process chamber; evacuating the process chamber to a vacuum state; introducing into the process chamber a mixture of a first gas containing fluorine and second gas containing hydrogen; making the mixture into plasma of low energy in the process chamber; supplying activated species of fluorine and hydrogen in the plasma onto the wafer to allow the species to be adsorbed in and on the SiO 2 film, a mixed ratio in the activated species being so set as not to effect etching of the SiO 2 film under a chemical action; irradiating the adsorbed activated species with ions in the plasma to excite the activated species and etching the SiO 2 film.
Claim 10
Independent Claim
134 words
A method for etching an SiO 2 film on a semiconductor wafer, comprising the steps of: positioning the semiconductor wafer in a process chamber; evacuating the process chamber to a vacuum state; introducing into the process chamber a mixture of a first gas containing fluorine and second gas containing hydrogen; making the mixture into plasma of low energy in the process chamber; supplying activated species of fluorine and hydrogen in the plasma onto the wafer to allow the species to be adsorbed in and on the SiO 2 film, a mixed ratio in the activated species being so set as not to effect etching of the SiO 2 film under a chemical action; irradiating the adsorbed activated species with ions in the plasma to excite the activated species and etching the SiO 2 film.
Claim 11
Dependent Claim
23 words
The method according to claim 8, further comprising the step of maintaining the semiconductor wafer at temperature less than 0° C. during etching.
Claim 12
Dependent Claim
35 words
The method according to claim 9, wherein the first gas is composed of NF 3 and second gas is composed of H 2 and an H2/NF 3 mixed ratio of the mixture is above 160.
Claim 13
Dependent Claim
22 words
The method according to claim 10, wherein the plasma is generated so that the ions therein have energy less than 20 ev.
References Cited (Backward Citations)
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