US4444618A
Expired / Lapsed
US
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Processes and gas mixtures for the reactive ion etching of aluminum and aluminum alloys
Assignee: Intersil Corp
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Filing: 1983-03-03
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Granted: 1984-04-24
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Expires: 2003-03-03
Abstract
Abstract A method and gas mixture of boron trichloride, carbon tetrachloride and oxygen useful for the reactive ion etching of aluminum and aluminum alloys to form metallizations for microelectronic devices and circuits is provided. The method and gas mixture provide consistent induction periods, high etch rates, high selectivity between photoresist and silicon dioxide, and minimal loading effects with good dimensional control. Also provided is a two step, two gas mixture process particularly useful in preventing linewidth loss due to excessive resist erosion during long overetches wherein the boron trichloride, carbon tetrachloride and oxygen gas mixture is used for etching and subsequently a boron trichloride-oxygen gas mixture is used for the overetch.
Inventors
- 👤 Richard J. Saia
- 👤 Bernard Gorowitz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 09:28
CPC Classifications
H; H10; H10P; H10P70/00; H10P70/20; H10P70/27; H10P70/273
Claims Analysis
Total Claims: 26
Claim 1
Independent Claim
28 words
A gas mixture for the reactive ion etching of aluminum and aluminum alloys comprising, by volume, 2-6% oxygen and 15-25% carbon tetrachloride with the balance being boron trichloride.
Claim 2
Dependent Claim
28 words
A gas mixture for the reactive ion etching of aluminum and aluminum alloys comprising, by volume, 2-6% oxygen and 15-25% carbon tetrachloride with the balance being boron trichloride.
Claim 3
Dependent Claim
18 words
The gas mixture of claim 1 comprising, by volume, 75% boron trichloride, 20% carbon tetrachloride and 5% oxygen.
Claim 4
Independent Claim
84 words
A method for the reactive ion etching of predetermined patterns in masked thin films of aluminum and aluminum alloys which comprises producing reactive species including ions from a gas mixture comprising by volume, 2-6% O 2 and 15-25% CCl 4 with the balance being BCl 3 and directionally etching the masked thin film with said respective species including ions to selectively remove the unmasked portion of said thin film thereby forming said predetermined pattern as the remaining masked aluminum or aluminum alloy thin film.
Claim 5
Independent Claim
84 words
A method for the reactive ion etching of predetermined patterns in masked thin films of aluminum and aluminum alloys which comprises producing reactive species including ions from a gas mixture comprising by volume, 2-6% O 2 and 15-25% CCl 4 with the balance being BCl 3 and directionally etching the masked thin film with said respective species including ions to selectively remove the unmasked portion of said thin film thereby forming said predetermined pattern as the remaining masked aluminum or aluminum alloy thin film.
Claim 6
Dependent Claim
24 words
The method of claim 3 wherein said gas mixture comprises, by volume, 75% BCl 3 , 20% CCl 4 and 5% O 2 .
Claim 7
Independent Claim
125 words
A method for the reactive ion etching of predetermined patterns in masked thin films of aluminum and aluminum alloys which comprises producing first reactive species including ions from a gas mixture comprising boron trichloride, carbon tetrachloride and oxygen and directionally etching the masked thin film with said first reactive species including ions for an etching time period to selectively remove the unmasked portions of said thin film thereby forming said predetermined pattern as the remaining masked aluminum or aluminum alloy thin film and thereafter producing second reactive species including ions from a gas mixture comprising boron trichloride and oxygen and subjecting said pattern to said second reactive species including ions for an overetching time period of from 20 to 50% of said etching time period.
Claim 8
Independent Claim
125 words
A method for the reactive ion etching of predetermined patterns in masked thin films of aluminum and aluminum alloys which comprises producing first reactive species including ions from a gas mixture comprising boron trichloride, carbon tetrachloride and oxygen and directionally etching the masked thin film with said first reactive species including ions for an etching time period to selectively remove the unmasked portions of said thin film thereby forming said predetermined pattern as the remaining masked aluminum or aluminum alloy thin film and thereafter producing second reactive species including ions from a gas mixture comprising boron trichloride and oxygen and subjecting said pattern to said second reactive species including ions for an overetching time period of from 20 to 50% of said etching time period.
Claim 9
Dependent Claim
32 words
The method of claim 5 wherein said boron trichloride, carbon tetrachloride and oxygen gas mixture comprises, by volume, 2-6% O 2 , 15-25% CCl 4 with the balance being BCl 3 .
Claim 10
Dependent Claim
24 words
The method of claim 6 wherein said gas mixture comprises, by volume, 75% BCl 3 , 20% CCl 4 and 5% O 2 .
Claim 11
Dependent Claim
26 words
The method of claim 5 wherein said boron trichloride and oxygen gas mixture comprises, by volume, 2-6% O 2 with the balance being BCl 3 .
Claim 12
Dependent Claim
20 words
The method of claim 8 wherein said gas mixture comprises, by volume, 94% BCl 3 and 6% O 2 .
Claim 13
Independent Claim
223 words
The method for reactive ion etching predetermined patterns in thin films of aluminum and aluminum alloys comprising the steps of: (a) forming on a substrate a thin film of the aluminum or aluminum alloy to be patterned; (b) depositing a resist layer on said thin film to be patterned; (c) patterning said resist layer to define features therein and expose one or more areas of said thin film therebeneath; (d) mounting said substrate with said thin film thereon to be patterned on a cathode electrode within a reaction chamber; (e) using said patterned resist layer as a mask; (f) directionally etching, in said reaction chamber, the exposed areas of said thin film by steps which comprise: (i) introducing into said chamber at a flow rate of 30 to 50 secm gas mixture comprising, by volume, 2-6% O 2 , 15-25% CCl 4 , with the balance being BCl 3 ; (ii) establishing a pressure within said chamber of 4 to 80 mtorr; and (iii) driving said cathode electrode via a radio-frequency generator, to establish a power density of approximately 0.25 watts per square centimeter at the surface of said substrate having said thin film and resist thereon; and (g) to selectively remove said exposed areas of said thin film thereby forming said predetermined pattern as the remaining unexposed areas of said thin film.
Claim 14
Independent Claim
223 words
The method for reactive ion etching predetermined patterns in thin films of aluminum and aluminum alloys comprising the steps of: (a) forming on a substrate a thin film of the aluminum or aluminum alloy to be patterned; (b) depositing a resist layer on said thin film to be patterned; (c) patterning said resist layer to define features therein and expose one or more areas of said thin film therebeneath; (d) mounting said substrate with said thin film thereon to be patterned on a cathode electrode within a reaction chamber; (e) using said patterned resist layer as a mask; (f) directionally etching, in said reaction chamber, the exposed areas of said thin film by steps which comprise: (i) introducing into said chamber at a flow rate of 30 to 50 secm gas mixture comprising, by volume, 2-6% O 2 , 15-25% CCl 4 , with the balance being BCl 3 ; (ii) establishing a pressure within said chamber of 4 to 80 mtorr; and (iii) driving said cathode electrode via a radio-frequency generator, to establish a power density of approximately 0.25 watts per square centimeter at the surface of said substrate having said thin film and resist thereon; and (g) to selectively remove said exposed areas of said thin film thereby forming said predetermined pattern as the remaining unexposed areas of said thin film.
Claim 15
Dependent Claim
13 words
The method of claim 10 wherein said flow rate is about 40 sccm.
Claim 16
Dependent Claim
24 words
The method of claim 10 wherein said gas mixture comprises, by volume, 75% BCl 3 , 20% CCl 4 and 5% O 2 .
Claim 17
Dependent Claim
12 words
The method of claim 10 wherein said pressure is about 70 mtorr.
Claim 18
Dependent Claim
18 words
The method of claim 10 wherein said radio-frequency generator is operated at a frequency of about 13.56 MHz.
Claim 19
Independent Claim
187 words
The method for reactive ion etching predetermined patterns in thin films of aluminum and aluminum alloys comprising the steps of: (a) forming on a substrate a thin film of the aluminum or aluminum alloy to be patterned; (b) depositing a resist layer on said thin film to be patterned; (c) patterning said resist layer to define features therein and expose one or more areas of said film therebeneath; (d) using said patterned resist layer as a mask, directionally etching, in a reaction chamber, for an etching time period, the exposed areas of said thin film with reactive species including ions from a first gas mixture comprising boron trichloride, carbon tetrachloride, and oxygen to selectively remove said exposed areas of said thin film thereby forming said predetermined pattern as the remaining unexposed areas of said thin film; (e) detecting an endpoint for the formation of said predetermined pattern by step (d); and (f) thereafter producing reactive species including ions from a second gas mixture comprising boron trichloride and oxygen and subjecting said pattern to an overetching time period of from 20 to 50% of said etching time period.
Claim 20
Independent Claim
187 words
The method for reactive ion etching predetermined patterns in thin films of aluminum and aluminum alloys comprising the steps of: (a) forming on a substrate a thin film of the aluminum or aluminum alloy to be patterned; (b) depositing a resist layer on said thin film to be patterned; (c) patterning said resist layer to define features therein and expose one or more areas of said film therebeneath; (d) using said patterned resist layer as a mask, directionally etching, in a reaction chamber, for an etching time period, the exposed areas of said thin film with reactive species including ions from a first gas mixture comprising boron trichloride, carbon tetrachloride, and oxygen to selectively remove said exposed areas of said thin film thereby forming said predetermined pattern as the remaining unexposed areas of said thin film; (e) detecting an endpoint for the formation of said predetermined pattern by step (d); and (f) thereafter producing reactive species including ions from a second gas mixture comprising boron trichloride and oxygen and subjecting said pattern to an overetching time period of from 20 to 50% of said etching time period.
Claim 21
Dependent Claim
155 words
The method of claim 15 wherein said substrate with said thin film thereon to be patterned is mounted on a cathode electrode within said chamber and said directionally etching step comprises: (i) introducing into said chamber at a flow rate of about 30 to 50 sccm said gas mixture comprising, by volume, 2-6% O 2 , 15-25% CCl 4 , with the balance being BCl 3 ; (ii) establishing a pressure within said chamber of from about 60 to 80 mtorr; (iii) by driving said cathode electrode via a radio-frequency generator, establishing a power density of approximately 0.25 watts per square centimeter at the surface of said substrate having said thin film and resist thereon; and, further, wherein step (f) is accomplished by shutting off the flow of said CCl 4 gas thereby causing the BCl 3 /O 2 gas mixture to be introduced at a flow rate of from about 22 to 42 sccm.
Claim 22
Dependent Claim
39 words
The method of claim 16 wherein the flow rate of said BCl 3 /CCl 4 /O 2 gas mixture is about 40 sccm and the flow rate of said BCl 3 /O 2 gas mixture is about 32 sccm.
Claim 23
Dependent Claim
25 words
The method of claim 16 wherein said first gas mixture comprises, by volume, 75% BCl 3 , 20% CCl 4 and 5% O 2 .
Claim 24
Dependent Claim
21 words
The method of claim 16 wherein said second gas mixture comprises, by volume, 94% BCl 3 and 6% O 2 .
Claim 25
Dependent Claim
12 words
The method of claim 16 wherein said pressure is about 70 mtorr.
Claim 26
Dependent Claim
18 words
The method of claim 16 wherein said radio-frequency generator is operated at a frequency of about 13.56 MHz.
References Cited (Backward Citations)
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1987-04-24 | 1987-10-24 | 1988-04-24 | $2000.00 | Window Closed / Lapsed |
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