US5378583A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Formation of microstructures using a preformed photoresist sheet
Assignee: Wisconsin Alumni Research Foundation
•
Filing: 1993-05-24
•
Granted: 1995-01-03
•
Expires: 2013-05-24
Abstract
Abstract In the formation of microstructures, a preformed sheet of photoresist, such as polymethylmethacrylate (PMMA), which is strain free, may be milled down before or after adherence to a substrate to a desired thickness. The photoresist is patterned by exposure through a mask to radiation, such as X-rays, and developed using a developer to remove the photoresist material which has been rendered susceptible to the developer. Micrometal structures may be formed by electroplating metal into the areas from which the photoresist has been removed. The photoresist itself may form useful microstructures, and can be removed from the substrate by utilizing a release layer between the substrate and the preformed sheet which can be removed by a remover which does not affect the photoresist. Multiple layers of patterned photoresist can be built up to allow complex three dimensional microstructures to be formed.
Inventors
- 👤 Henry Guckel
- 👤 Todd R. Christenson
- 👤 Kenneth Skrobis
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 20:21
CPC Classifications
G; G03; G03F; G03F7/00; G03F7/20; G03F7/2037; G03F7/2039; G03F7/26; G03F7/38; B; B81; B81C; B81C1/00; B81C1/00349; B81C1/0038; G03F7/0035; H; H10; H10P; H10P76/00; H10P76/20; H10P76/204; H10P76/2041; B81C2201/00; B81C2201/01; B81C2201/0101; B81C2201/0128; B81C2201/0156; B81C2201/0159; B81C2201/0174; B81C2201/019; B81C2201/03; B81C2201/032; Y; Y10; Y10S; Y10S430/00; Y10S430/167; Y10S430/168; Y10T; Y10T428/00; Y10T428/31504
Claims Analysis
Total Claims: 48
Claim 1
Independent Claim
86 words
A method of forming microstructures comprising the steps of: (a) providing a preformed sheet of photoresist material which can be exposed to radiation to affect its susceptibility to a developer; (b) exposing the photoresist sheet in a pattern to radiation which will change its susceptibility to a developer; (c) mechanically removing the material of the photoresist sheet to reduce the thickness of the sheet to a desired thickness; and (d) applying a developer to the exposed photoresist to remove photoresist which is susceptible to the developer.
Claim 2
Independent Claim
86 words
A method of forming microstructures comprising the steps of: (a) providing a preformed sheet of photoresist material which can be exposed to radiation to affect its susceptibility to a developer; (b) exposing the photoresist sheet in a pattern to radiation which will change its susceptibility to a developer; (c) mechanically removing the material of the photoresist sheet to reduce the thickness of the sheet to a desired thickness; and (d) applying a developer to the exposed photoresist to remove photoresist which is susceptible to the developer.
Claim 3
Dependent Claim
73 words
The method of claim 1 including the initial steps of applying a thin layer of metal to a subtrate as a plating base, adhering the preformed sheet of photoresist to the plating base, then after all of the steps of claim 1, the additional steps of electroplating metal in the areas in which the photoresist has been removed, and then removing the remaining photoresist to leave the electroplated metal structures on the substrate.
Claim 4
Dependent Claim
11 words
The method of claim 1 wherein the photoresist sheet is PMMA.
Claim 5
Dependent Claim
19 words
The method of claim 3 wherein the PMMA of the photoresist sheet is very high molecular weight linear PMMA.
Claim 6
Dependent Claim
45 words
The method of claim 2 wherein the material of the photoresist sheet is very high molecular weight linear PMMA, and wherein the step of removing the remaining photoresist is carried out by exposing the photoresist to a bath of a solvent which dissolves the PMMA.
Claim 7
Dependent Claim
18 words
The method of claim 5 wherein the solvent which is used to dissolve the PMMA is methylene chloride.
Claim 8
Dependent Claim
27 words
The method of claim 3 wherein the step of exposing the photoresist in a pattern is carried out by exposing the photoresist to X-rays from a synchrotron.
Claim 9
Dependent Claim
74 words
The method of claim 4 including the steps of spinning on a thin initial layer of non-crosslinked PMMA onto the surface of a substrate, solidifying the initial layer of PMMA, applying the preformed sheet of PMMA to the initial layer, and applying a liquid methylmethacrylate monomer to the interface between the preformed sheet and the initial layer to provide adhesion between the preformed sheet and the initial layer at the interface between the two.
Claim 10
Dependent Claim
61 words
The method of claim 1 including the initial steps of applying a sacrificial layer to a substrate and adhering the preformed sheet to the sacrificial layer, then after all of the steps of claim 1, the additional step of removing the sacrificial layer with a remover which does not affect the photoresist material to free the remaining photoresist from the substrate.
Claim 11
Dependent Claim
13 words
The method of claim 9 wherein the material of the photoresist is PMMA.
Claim 12
Dependent Claim
23 words
The method of claim 10 wherein the sacrificial layer is a material selected from the group consisting of titanium and partially imidized polyimide.
Claim 13
Dependent Claim
19 words
The method of claim 10 wherein the PMMA of the photoresist is a very high molecular weight linear PMMA.
Claim 14
Dependent Claim
14 words
The method of claim 10 wherein the PMMA of the photoresist is crosslinked PMMA.
Claim 15
Dependent Claim
42 words
The method of claim 1 wherein the preformed sheet of photoresist is at least 1 mm thick, and in the step of mechanically removing the material of the photoresist sheet the thickness of the sheet is reduced to less than 1 mm.
Claim 16
Independent Claim
194 words
A method of forming microstructures comprising the steps of: (a) providing a first preformed sheet of photoresist material which can be exposed to radiation to affect its susceptibility to a developer; (b) exposing the photoresist sheet to radiation in a pattern to which will change its susceptibility to a developer; (c) mechanically removing the material of the photoresist sheet to reduce the thickness of the sheet to a desired thickness constituting a first layer of photoresist; (d) providing a second preformed sheet of photoresist material which may be exposed to radiation to affect its susceptibility to a developer; (e) adhering the second photoresist sheet to the first layer of photoresist to form a laminate; (f) mechanically removing the material of the second photoresist sheet to reduce the thickness of the sheet to a desired thickness constituting a second layer of photoresist; (g) exposing the first and second layers of the photoresist to a pattern of radiation which will change the susceptibility of the photoresist of the second layer to a developer; and (h) removing the photoresist in the first and second layers which is susceptible to a developer using a developer for the photoresist.
Claim 17
Independent Claim
194 words
A method of forming microstructures comprising the steps of: (a) providing a first preformed sheet of photoresist material which can be exposed to radiation to affect its susceptibility to a developer; (b) exposing the photoresist sheet to radiation in a pattern to which will change its susceptibility to a developer; (c) mechanically removing the material of the photoresist sheet to reduce the thickness of the sheet to a desired thickness constituting a first layer of photoresist; (d) providing a second preformed sheet of photoresist material which may be exposed to radiation to affect its susceptibility to a developer; (e) adhering the second photoresist sheet to the first layer of photoresist to form a laminate; (f) mechanically removing the material of the second photoresist sheet to reduce the thickness of the sheet to a desired thickness constituting a second layer of photoresist; (g) exposing the first and second layers of the photoresist to a pattern of radiation which will change the susceptibility of the photoresist of the second layer to a developer; and (h) removing the photoresist in the first and second layers which is susceptible to a developer using a developer for the photoresist.
Claim 18
Dependent Claim
44 words
The method of claim 15 including the step of adhering the first preformed sheet of photoresist material to a substrate before the steps of exposing the first photoresist sheet to a pattern of radiation and mechanically removing the material of the first photoresist sheet.
Claim 19
Dependent Claim
87 words
The method of claim 16 wherein the step of adhering the first sheet of photoresist to the substrate includes the step of applying a thin layer of metal to the substrate as a plating base and adhering the preformed sheet of the photoresist to the plating base, then after all of the steps of claim 16, the additional steps of electroplating metal in the areas in which the photoresist has been removed, and then removing the remaining photoresist to leave the electroplated metal structures on the substrate.
Claim 20
Dependent Claim
16 words
The method of claim 15 wherein the first and second photoresist sheets are formed of PMMA.
Claim 21
Dependent Claim
19 words
The method of claim 18 wherein the PMMA of the photoresist sheets is very high molecular weight linear PMMA.
Claim 22
Dependent Claim
45 words
The method of claim 17 wherein the material of the photoresist sheets is very high molecular weight linear PMMA, and wherein the step of removing the remaining photoresist is carried out by exposing the photoresist to a bath of a solvent which dissolves the PMMA.
Claim 23
Dependent Claim
29 words
The method of claim 15 wherein the steps of exposing the photoresist sheets in a pattern is carried out by exposing each photoresist sheet to X-rays from a synchrotron.
Claim 24
Dependent Claim
126 words
The method of claim 15 including the additional steps of providing a third preformed sheet of photoresist material which can be exposed to radiation to change its susceptibility to a developer; adhering the third photoresist sheet to the second layer of the laminate; mechanically removing the material of the third photoresist sheet adhered to the second layer to reduce the thickness of the sheet to a desired thickness comprising a third layer of the laminate; exposing the third layer of photoresist in a pattern to radiation which will change the susceptibility of the photoresist to a developer, and then carrying out the step of removing the photoresist susceptible to a developer in each of the first, second and third layers utilizing a developer for the photoresist.
Claim 25
Dependent Claim
42 words
The method of claim 15 wherein the step of removing the photoresist susceptible to a developer in the first and second layers is carried out before the second photoresist sheet constituting the second layer is adhered to the first layer of photoresist.
Claim 26
Independent Claim
172 words
A method of forming microstructures comprising the steps of: (a) providing a first preformed sheet of photoresist material which can be exposed to radiation to affect it susceptibility to a developer; (b) exposing the first photoresist sheet to radiation in a pattern which will result in susceptibility of the photoresist to a developer partially but not entirely through the thickness of the photoresist sheet; (c) adhering the first photoresist sheet on the side which has photoresist which is susceptible to a developer to a layer of photoresist which has a pattern of areas therein which are susceptible to the developer, to form a laminate; (d) mechanically removing the material of the first preformed photoresist sheet to reduce the thickness of the sheet to expose the areas of the first preformed sheet which are susceptible to removal by the developer; and (e) applying a developer to the laminate to remove photoresist which is susceptible to the developer to leave a pattern of voids in the first photoresist sheet and the underlying photoresist layer.
Claim 27
Independent Claim
172 words
A method of forming microstructures comprising the steps of: (a) providing a first preformed sheet of photoresist material which can be exposed to radiation to affect it susceptibility to a developer; (b) exposing the first photoresist sheet to radiation in a pattern which will result in susceptibility of the photoresist to a developer partially but not entirely through the thickness of the photoresist sheet; (c) adhering the first photoresist sheet on the side which has photoresist which is susceptible to a developer to a layer of photoresist which has a pattern of areas therein which are susceptible to the developer, to form a laminate; (d) mechanically removing the material of the first preformed photoresist sheet to reduce the thickness of the sheet to expose the areas of the first preformed sheet which are susceptible to removal by the developer; and (e) applying a developer to the laminate to remove photoresist which is susceptible to the developer to leave a pattern of voids in the first photoresist sheet and the underlying photoresist layer.
Claim 28
Dependent Claim
114 words
The method of claim 24 including, before the step of adhering the first photoresist sheet to the photoresist layer, the additional steps of providing the photoresist layer from a preformed sheet of photoresist material which can be exposed to radiation to affect its susceptibility to a developer partially but not entirely through the thickness of the photoresist sheet, mechanically removing the material of the photoresist sheet from the side opposite the exposed side of the sheet to reduce the thickness of the sheet to fully expose the areas of the sheet which are susceptible to the developer to provide the photoresist layer, and thereafter adhering the first preformed photoresist sheet to the photoresist layer.
Claim 29
Dependent Claim
57 words
The method of claim 25 including before the step of mechanically removing the material of the preformed photoresist sheet from which the photoresist layer is formed, the step of adhering the exposed side of that preformed photoresist sheet to a substrate, and then carrying out the step of mechanically removing the material of the preformed photoresist sheet.
Claim 30
Dependent Claim
18 words
The method of claim 24 wherein the photoresist layer and the preformed photoresist sheet are formed of PMMA.
Claim 31
Dependent Claim
98 words
The method of claim 26 wherein the step of adhering the photoresist layer to the substrate includes the step of applying a thin layer of metal to the substrate as a plating base and adhering the photoresist layer to the plating base, and then after all of the steps of claim 26 wherein the areas susceptible to developer in the photoresist have been removed to leave voids, the additional steps of electroplating metal in the voids in which the photoresist has been removed, and then removing the remaining photoresist to leave the electroplated metal structures on the substrate.
Claim 32
Dependent Claim
24 words
The method of claim 26 wherein the first preformed photoresist sheet and the photoresist layer are formed of very high molecular weight linear PMMA.
Claim 33
Independent Claim
84 words
A method of forming microstructures comprising the steps of: (a) providing a first preformed sheet of PMMA photoresist material; (b) exposing the first photoresist sheet in a pattern to X-rays to render exposed areas of the photoresist sheet susceptible to a developer; (c) mechanically removing the material of the first photoresist sheet to reduce the thickness of the sheet to a desired thickness; and (d) applying a developer to the first photoresist sheet to remove the exposed photoresist which is susceptible to the developer.
Claim 34
Independent Claim
84 words
A method of forming microstructures comprising the steps of: (a) providing a first preformed sheet of PMMA photoresist material; (b) exposing the first photoresist sheet in a pattern to X-rays to render exposed areas of the photoresist sheet susceptible to a developer; (c) mechanically removing the material of the first photoresist sheet to reduce the thickness of the sheet to a desired thickness; and (d) applying a developer to the first photoresist sheet to remove the exposed photoresist which is susceptible to the developer.
Claim 35
Dependent Claim
74 words
The method of claim 30 including the initial steps of applying a thin layer of metal to a substrate as a plating base, adhering the first preformed sheet of photoresist to the plating base, then after all of the steps of claim 30, the additional steps of electroplating metal in the areas in which the photoresist has been removed, and then removing the remaining photoresist to leave the electroplated metal structures on the substrate.
Claim 36
Dependent Claim
46 words
The method of claim 31 wherein the material of the first photoresist sheet is very high molecular weight linear PMMA, and wherein the step of removing the remaining photoresist is carried out by exposing the photoresist to a bath of a solvent which dissolves the PMMA.
Claim 37
Dependent Claim
18 words
The method of claim 32 wherein the solvent which is used to dissolve the PMMA is methylene chloride.
Claim 38
Dependent Claim
77 words
The method of claim 30 including the steps of spinning on a thin initial layer of non-crosslinked PMMA onto the surface of a substrate and solidifying the initial layer of PMMA, applying the first preformed sheet of PMMA to the initial layer, and applying a liquid methyl methacrylate monomer to the interface between the preformed sheet and the initial layer to provide adhesion between the preformed sheet and the initial layer at the interface between the two.
Claim 39
Dependent Claim
43 words
The method of claim 30 wherein the first preformed sheet of photoresist is at least 1 mm thick, and in the step of mechanically removing the material of the photoresist sheet the thickness of the sheet is reduced to less than 1 mm.
Claim 40
Dependent Claim
99 words
The method of claim 30 further comprising the steps of: (a) providing a second preformed sheet of PMMA photoresist material; (b) adhering the second photoresist sheet to the first photoresist sheet to form a laminate; (c) mechanically removing the material of the second photoresist sheet to reduce the thickness of the sheet to a desired thickness; (d) exposing the second photoresist sheet to a pattern of X-rays which will render the exposed areas of the second photoresist sheet susceptible to a developer; and (e) removing the exposed photoresist in the second photoresist sheet using a developer for the photoresist.
Claim 41
Dependent Claim
42 words
The method of claim 36 including the step of adhering the first preformed photoresist sheet to a substrate before the steps of exposing the first photoresist sheet to a pattern of radiation and mechanically removing the material of the first photoresist sheet.
Claim 42
Dependent Claim
87 words
The method of claim 37 wherein the step of adhering the first sheet of photoresist to the substrate includes the step of applying a thin layer of metal to the substrate as a plating base and adhering the preformed sheet of the photoresist to the plating base, then after all of the steps of claim 37, the additional steps of electroplating metal in the areas in which the photoresist has been removed, and then removing the remaining photoresist to leave the electroplated metal structures on the substrate.
Claim 43
Dependent Claim
45 words
The method of claim 38 wherein the material of the photoresist sheets is very high molecular weight linear PMMA, and wherein the step of removing the remaining photoresist is carried out by exposing the photoresist to a bath of a solvent which dissolves the PMMA.
Claim 44
Dependent Claim
108 words
The method of claim 36 including the additional steps of providing a third preformed sheet of PMMA photoresist; adhering the third photoresist sheet to the second photoresist sheet of the laminate; mechanically removing the material of the third photoresist sheet adhered to the second photoresist sheet to reduce the thickness of the sheet to a desired thickness; exposing the third sheet of photoresist in a pattern to X-rays which will render the exposed areas of the photoresist susceptible to a developer, and then carrying out the step of removing the exposed photoresist in each of the first, second and third photoresist sheets utilizing a developer for the photoresist.
Claim 45
Dependent Claim
38 words
The method of claim 36 wherein the step of removing the exposed photoresist with a developer in the first and second photoresist sheets is carried out before the second photoresist sheet is adhered to the first photoresist sheet.
Claim 46
Dependent Claim
42 words
The method of claim 36 wherein the step of adhering the second photoresist sheet to the first photoresist sheet is carried out after the steps of exposing the second photoresist sheet to a pattern of X-rays and of removing the exposed photoresist.
Claim 47
Dependent Claim
34 words
The method of claim 36 wherein the step of adhering the second photoresist sheet to the first photoresist sheet is carried out before the step of applying a developer to the first photoresist sheet.
Claim 48
Dependent Claim
27 words
The method of claim 36 wherein the second photoresist sheet is adhered to the first photoresist sheet by wetting the interface between the sheets with methyl methacrylate.
References Cited (Backward Citations)
US3449221A
Cited
US3535137A
Cited
US3886584A
Cited
US4035522A
Cited
US3984582A
Cited
US4108938A
Cited
US4107351A
Cited
US4422905A
Cited
US4351653A
Cited
US4541977A
Cited
US4493753A
Cited
US4563251A
Cited
US4563250A
Cited
US4703559A
Cited
US4705605A
Cited
US4693791A
Cited
US4694548A
Cited
US4698285A
Cited
US4661212A
Cited
US4780382A
Cited
US4797211A
Cited
US4738010A
Cited
US4784935A
Cited
US4872888A
Cited
US5189777A
Cited
US5206983A
Cited
US5190637A
Cited
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