US4780177A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Excimer laser patterning of a novel resist
Assignee: Lockheed Martin Corp
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Filing: 1988-02-05
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Granted: 1988-10-25
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Expires: 2008-02-05
Abstract
Abstract A dual layer resist configuration is employed for photopatterning high resolution conductive patterns on underlying polymeric or ceramic substrates, particularly substrates exhibiting surface roughness and non-planar design features such as channels, bosses and ridges. More particularly, a thin underlayer of ablatable photoabsorptive polymer is disposed on a metal coated substrate, after which a thicker layer of substantially transparent material is disposed over the polymer. A beam of laser energy, such as that produced by an ultraviolet excimer laser, is directed through the upper layer and is absorbed by the lower layer which is ablated and simultaneously removes the thick layer above it. This results in the ability to etch high resolution features on polymeric and other substrates, particularly copper coated polyetherimide circuit boards. The resist system is also applicable to VLSI wafers even though such wafers usually do not exhibit surface roughness on the scale generally considered herein. It is also equally applicable in various high density interconnect systems used for the direct connection of chip devices. A mask for patterning and a method for making it are also seen to be desirable because of the high laser energy densities generally desired for thorough ablation.
Inventors
- 👤 Robert J. Wojnarowski
- 👤 Charles W. Eichelberger
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 13:30
CPC Classifications
G; G03; G03F; G03F7/00; G03F7/20; G03F7/2002; G03F7/2004; G03F7/2006; B; B44; B44C; B44C1/00; B44C1/22; H; H05; H05K; H05K3/00; H05K3/0073; H05K3/0082; H10; H10W; H10W70/00; H10W70/60; H10W70/611; H10W70/614; H05K2203/00; H05K2203/05; H05K2203/0502; H05K2203/0505; H05K2203/0562; H05K2203/0577; H05K2203/10; H05K2203/107; H05K3/0011; H05K3/0017; H05K3/0026; H05K3/0032; H05K3/02; H05K3/06; H05K3/061; H05K3/064; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49002; Y10T29/49117; Y10T29/49124; Y10T29/49155; Y10T428/00; Y10T428/12; Y10T428/12361; Y10T428/24; Y10T428/24273; Y10T428/24322; Y10T428/31504
Claims Analysis
Total Claims: 38
Claim 1
Independent Claim
25 words
A two level resist configuration comprising a thin underlayer of ablatable photoabsorptive polymer and a thick upper layer of substantially transparent material overlying said polymer.
Claim 2
Dependent Claim
25 words
A two level resist configuration comprising a thin underlayer of ablatable photoabsorptive polymer and a thick upper layer of substantially transparent material overlying said polymer.
Claim 3
Dependent Claim
15 words
The configuration of claim 1 in which said underlayer is photoabsorptive in the ultraviolet range.
Claim 4
Dependent Claim
21 words
The configuration of the claim 1 in which said underlayer is between about 0.1 microns and about 10 microns in thickness.
Claim 5
Dependent Claim
20 words
The configuration of claim 1 in which said upper layer is between about 1 and about 100 microns in thickness.
Claim 6
Dependent Claim
18 words
The configuration of claim 1 in which said underlayer comprises material selected from the group consisting of polysulfones.
Claim 7
Dependent Claim
22 words
The configuration of claim 1 in which said upper layer comprises material selected from the group consisting of polymethylmethacrylate, polyethylmethacrylate and polycarbonates.
Claim 8
Dependent Claim
13 words
The configuration of claim 1 in which said upper layer is ultraviolet transmissive.
Claim 9
Dependent Claim
21 words
The configuration of claim 1 in which said upper layer and said underlayer exhibit differential solubilities with respect to each other.
Claim 10
Dependent Claim
18 words
The configuration of claim 1 in which said underlayer is disposed in contact with a metal coated substrate.
Claim 11
Dependent Claim
11 words
The configuration of claim 9 in which said metal comprises copper.
Claim 12
Dependent Claim
12 words
The configuration of claim 9 in which said substrate comprises a polymer.
Claim 13
Independent Claim
112 words
A method for photopatterning conductive patterns, said method comprising the steps of: disposing a thin layer of ablatable photoabsorptive polymer on a substrate having a conductive layer thereon, so that said polymer material is in contact with said conductive layer; disposing a thick layer of substantially transparent material over said polymer, said photoabsorptivity and said transparency being determined with respect to the same frequency range; and directing a beam of laser energy through said thick layer so as to ablate said polymer layer and so as to simultaneously remove said thick layer above said ablated polymer layer, whereby select portions of said conductive layer are exposed through said thick and thin layers.
Claim 14
Independent Claim
112 words
A method for photopatterning conductive patterns, said method comprising the steps of: disposing a thin layer of ablatable photoabsorptive polymer on a substrate having a conductive layer thereon, so that said polymer material is in contact with said conductive layer; disposing a thick layer of substantially transparent material over said polymer, said photoabsorptivity and said transparency being determined with respect to the same frequency range; and directing a beam of laser energy through said thick layer so as to ablate said polymer layer and so as to simultaneously remove said thick layer above said ablated polymer layer, whereby select portions of said conductive layer are exposed through said thick and thin layers.
Claim 15
Dependent Claim
18 words
The method of claim 12 in which said thin layer is selected from the group consisting of polysulfones.
Claim 16
Dependent Claim
21 words
The method of claim 12 in which said thick layer is selected from the group consisting of polymethylmethacrylate, polyethylmethacrylate and polycarbonates.
Claim 17
Dependent Claim
16 words
The method of claim 12 in which said laser energy is produced by an excimer laser.
Claim 18
Dependent Claim
16 words
The method of claim 12 in which said laser energy is in the ultraviolet frequency region.
Claim 19
Dependent Claim
21 words
The method of claim 12 in which said thin layer is between about 0.1 microns and about 10 microns in thickness.
Claim 20
Dependent Claim
20 words
The method of claim 12 in which said thick layer is between approximately 1 and approximately 100 microns in thickness.
Claim 21
Dependent Claim
15 words
The method of claim 12 further including the step of etching said exposed conductive layer.
Claim 22
Dependent Claim
16 words
The method of claim 19 further including the step of removing said thick and thin layers.
Claim 23
Dependent Claim
22 words
The method of claim 12 further including the step of depositing additional conductive material on the exposed portion of said conductive layer.
Claim 24
Dependent Claim
16 words
The method of claim 21 further including the step of removing said thick and thin layers.
Claim 25
Dependent Claim
39 words
The method of claim 22 further including the step of removing a sufficient thickness of said conductive layer, so that the remaining pattern is substantially the same pattern as produced in said thick and thin layers by said beam.
Claim 26
Dependent Claim
12 words
The method of claim 12 in which said conductive layer comprises copper.
Claim 27
Dependent Claim
14 words
The method of claim 12 in which said beam is directed through a mask.
Claim 28
Dependent Claim
16 words
The method of claim 25 in which said mask is not in contact with said substrate.
Claim 29
Dependent Claim
13 words
The method of claim 12 in which said substrate exhibits a non-planar surface.
Claim 30
Dependent Claim
12 words
The method of claim 12 in which said substrate contains feed-through apertures.
Claim 31
Dependent Claim
18 words
The method of claim 12 further including removing said ablated material by vacuum means as it is produced.
Claim 32
Dependent Claim
19 words
The method of claim 12 further including removing said ablated material by blowing it away from the ablation side.
Claim 33
Dependent Claim
11 words
The method of claim 12 in which said beam is focused.
Claim 34
Dependent Claim
49 words
The method of claim 12 further including the steps of: depositing additional conductive material on conductive material exposed by said laser beam; removing said unexposed polymer and said transparent overlayer material; and removing sufficient conductor material so that conductor material is present only where said laser beam was directed.
Claim 35
Dependent Claim
47 words
A mask for use in high energy density laser patterning, said mask comprising: a quartz substrate; a patterned titanium layer disposed on said substrate; a patterned reflective metal layer disposed over said titanium layer, said reflective layer comprising material selected from the group consisting of aluminum and
Claim 36
Dependent Claim
47 words
A mask for use in high energy density laser patterning, said mask comprising: a quartz substrate; a patterned titanium layer disposed on said substrate; a patterned reflective metal layer disposed over said titanium layer, said reflective layer comprising material selected from the group consisting of aluminum and
Claim 37
Independent Claim
69 words
A method for making a mask for use in high energy density laser patterning, said method comprising the steps of: cleansing a quartz substrate in a mixture of sulfuric acid and oxidizer; rinse and vacuum dry said cleansed substrate at an elevated temperature; deposit a layer of titanium on said substrate; deposit a layer of reflective metal over said titanium layer; and pattern said titanium and reflective metal layers.
Claim 38
Independent Claim
69 words
A method for making a mask for use in high energy density laser patterning, said method comprising the steps of: cleansing a quartz substrate in a mixture of sulfuric acid and oxidizer; rinse and vacuum dry said cleansed substrate at an elevated temperature; deposit a layer of titanium on said substrate; deposit a layer of reflective metal over said titanium layer; and pattern said titanium and reflective metal layers.
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) | 1991-10-25 | 1992-04-25 | 1992-10-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-10-25 | 1996-04-25 | 1996-10-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-10-25 | 2000-04-25 | 2000-10-25 | $7700.00 | Window Closed / Lapsed |