Patent US4215192A successfully refreshed from Google Patents.
US4215192A
Expired / Lapsed
US
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X-ray lithography apparatus and method of use
Assignee: Applied Biosystems Inc
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Filing: 1978-01-16
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Granted: 1980-07-29
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Expires: 1998-01-16
Abstract
Abstract In order to obtain shorter exposure time and to obtain a longer life in x-ray lithography apparatus, an x-ray target made of tungsten is utilized and the apparatus operated to generate the tungsten M-line, this line being at a wavelength which will be absorbed by the resist normally used in lithography. To develop the resist, which was initially designed for use in an electron beam lithography, a developing method is used in which a initial short development with a high concentration is first carried out followed by a longer, full development with a concentration which is approximately the lowest at which complete development will take place.
Inventors
- 👤 William D. Buckley
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 02:03
CPC Classifications
G; G03; G03F; G03F7/00; G03F7/70; G03F7/70008; G03F7/70033; G03F7/20; G03F7/2037; G03F7/2039; G03F7/708; G03F7/70858; G03F7/70866; H; H01; H01J; H01J35/00; H01J35/02; Y; Y10; Y10S; Y10S430/00; Y10S430/167; Y10S430/168
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
96 words
A method of performing x-ray lithography comprising: (a) coating the substrate on which the lithography is to be carried out with a resist; (b) disposing an x-ray apparatus having a target means capable of generating M-line x-ray radiation having a wavelength in the range of between about 4 and about 14 angstroms so as to generate radiation which will impinge on and expose said coated substrate; (c) operating said x-ray source so as to generate the M-line radiation; (d) disposing a mask between said source and said substrate; and (e) exposing said substrate to said radiation.
Claim 2
Independent Claim
96 words
A method of performing x-ray lithography comprising: (a) coating the substrate on which the lithography is to be carried out with a resist; (b) disposing an x-ray apparatus having a target means capable of generating M-line x-ray radiation having a wavelength in the range of between about 4 and about 14 angstroms so as to generate radiation which will impinge on and expose said coated substrate; (c) operating said x-ray source so as to generate the M-line radiation; (d) disposing a mask between said source and said substrate; and (e) exposing said substrate to said radiation.
Claim 3
Dependent Claim
29 words
The method of claim 1 wherein said target is selected from the group consisting of tungsten, alloys of tungsten, and tungsten compounds, so as to generate a tungsten M-line.
Claim 4
Dependent Claim
21 words
The method of claim 2 wherein said step of operating comprises operating said x-ray source at a voltage above 5 kv.
Claim 5
Dependent Claim
22 words
The method according to claim 3 wherein said step of operating comprises operating at a voltage in the vincinity of 20 kv.
Claim 6
Dependent Claim
35 words
The method according to claim 4 wherein said step of operating includes using as a window in said x-ray apparatus a window made of beryllium and having a thickness of not more than 100 μm.
Claim 7
Dependent Claim
24 words
The method according to claim 5 wherein said step of disposing comprises disposing a window which has a thickness no greater than 25 μm.
Claim 8
Dependent Claim
69 words
The method of claim 1 wherein said resist is COP resist and further including the steps of first developing the exposed resist in a developing solution having a concentration of approximately 5:1.8, the concentration being the ratio of MEK developer to an ethanol solvent for a short period of time and then developing said resist in a developer concentration of approximately 5:2.7 until all of said resist is developed.
Claim 9
Dependent Claim
54 words
The method of claim 7 wherein said steps of developing comprise: (a) developing for a first period of time with said 5:1.8 developing solution; (b) developing for a second period of time with both said 5:1.8 developing solution and said 5:2.7 developer; and (c) developing for a third period only with said 5:2.7 developer.
Claim 10
Dependent Claim
16 words
The method of claim 8 wherein all of said developing steps are carried out by spraying.
Claim 11
Dependent Claim
51 words
The method of claim 8 wherein said resist is exposed so as to obtain about a 50% developed thickness and wherein said first developing step is carried out for 5 seconds; said second step is carried out for 10 seconds and wherein said third step is carried out for 5 seconds.
Claim 12
Dependent Claim
53 words
The method according to claim 1 and further including the step of disposing a filter between said source and said substrate prior to exposing, said filter being such as to filter out M-line radiation but to pass L-line radiation whereby alignment of the mask and substrate can be carried out prior to exposure.
Claim 13
Dependent Claim
17 words
The method according to claim 1 and further including the step of doping said resist with bromine.
Claim 14
Dependent Claim
67 words
An improved method of developing a COP resist which as been exposed to x-ray radiation comprising the steps of first developing said resist in a developing solution having a concentration of approximately 5:1.8, the concentration being the ratio of MEK developer to an ethanol solvent for a short period of time and then developing said resist in a lower concentration of approximately 5:2.7 until development is completed.
Claim 15
Dependent Claim
67 words
An improved method of developing a COP resist which as been exposed to x-ray radiation comprising the steps of first developing said resist in a developing solution having a concentration of approximately 5:1.8, the concentration being the ratio of MEK developer to an ethanol solvent for a short period of time and then developing said resist in a lower concentration of approximately 5:2.7 until development is completed.
Claim 16
Dependent Claim
54 words
The method of claim 13 wherein said steps of developing comprise: (a) developing for a first period of time with said 5:1.8 developing solution; (b) developing for a second period of time with both said 5:1.8 developing solution and said 5:2.7 developer; and (c) developing for a third period only with said 5:2.7 developer.
Claim 17
Dependent Claim
16 words
The method of claim 14 wherein all of said developing steps are carried out by spraying.
Claim 18
Dependent Claim
51 words
The method of claim 14 wherein said resist is exposed so as to obtain about a 50% developed thickness and wherein said first developing step is carried out for 5 seconds; said second step is carried out for 10 seconds and wherein said third step is carried out for 5 seconds.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-07-29 | 1984-01-28 | 1984-07-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-07-29 | 1988-01-28 | 1988-07-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-07-29 | 1992-01-28 | 1992-07-29 | $7700.00 | Window Closed / Lapsed |