Patent US5667934A successfully refreshed from Google Patents.
US5667934A
Expired / Lapsed
US
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Thermally stable photoimaging composition
Assignee: International Business Machines Corp
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Filing: 1990-10-09
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Granted: 1997-09-16
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Expires: 2010-10-09
Abstract
Abstract A thermally stable photoimaging composition and a method of using the same, especially on circuit boards as a solder mask is provided. The composition includes a polymerizable resin or resin system, a cationic photoinitiator, a solvent, and an optically transparent ceramic filler. Preferably, the composition has a coefficient of thermal expansion of about 28-40 ppm/°C., which closely matches the coefficient of thermal expansion of the solder used on the circuit board components.
Inventors
- 👤 Voya Rista Markovich
- 👤 Ashit Arvind Mehta
- 👤 Eugene Roman Skarvinko
- 👤 David Wei Wang
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 22:19
CPC Classifications
G; G03; G03F; G03F7/00; G03F7/004; G03F7/0047; H; H05; H05K; H05K3/00; H05K3/22; H05K3/28; H05K3/285; H05K3/287
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
67 words
A photo-patternable solder mask thermally stable at 360° C., consisting essentially of a photosensitive cationic photoinitiator admixed with a cationic polymerizable epoxy resin, a solvent and a filler consisting essentially of an optically transparent silicon dioxide filler transparent to wavelength of 310 to 400 nanometers, said composition having a coefficient of thermal expansion of 28-40 ppm/°C., wherein said solder mask is both an encapsulant and a dielectric.
Claim 2
Dependent Claim
67 words
A photo-patternable solder mask thermally stable at 360° C., consisting essentially of a photosensitive cationic photoinitiator admixed with a cationic polymerizable epoxy resin, a solvent and a filler consisting essentially of an optically transparent silicon dioxide filler transparent to wavelength of 310 to 400 nanometers, said composition having a coefficient of thermal expansion of 28-40 ppm/°C., wherein said solder mask is both an encapsulant and a dielectric.
Claim 3
Dependent Claim
19 words
A composition according to claim 1, wherein the epoxy resin is an epoxidized octafunctional bisphenol A formaldehyde novolak resin.
Claim 4
Dependent Claim
35 words
A composition according to claim 2, wherein the epoxy resin has an epoxide value of approximately 4.57 equivalents per kilogram, a weight per epoxide of about 215 and a melting point of about 82° C.
Claim 5
Dependent Claim
26 words
A composition according to claim 1, wherein the epoxy resin is present from about 30-70% by weight of the combined epoxy resin and ceramic filler weight.
Claim 6
Dependent Claim
26 words
A composition according to claim 1, wherein the epoxy resin is present from about 50% by weight of the combined epoxy resin transparent ceramic filler weight.
Claim 7
Dependent Claim
14 words
A composition according to claim 1, wherein the photo-initiator is a triarylsulfonium hexafluoroantimonate salt.
Claim 8
Dependent Claim
23 words
A composition according to claim 1, wherein the initiator is a mixture of a triarylsulfonium hexafluorantimonate salt and a tetraryl disulfonium hexafluoroantimonate salt.
Claim 9
Dependent Claim
17 words
A composition according to claim 1, wherein the initiator is iron arene compound, CIBA GEIGY RD 87-356.
Claim 10
Dependent Claim
19 words
A composition according to claim 1, which contains from approximately 0.5% to approximately 10% cationic initiator per resin weight.
Claim 11
Dependent Claim
15 words
A composition according to claim 1, which contains approximately 10% cationic initiator per resin weight.
Claim 12
Dependent Claim
15 words
A composition according to claim 1, wherein the optically transparent ceramic filler is silicon dioxide.
Claim 13
Dependent Claim
29 words
A composition according to claim 1, which contains optically transparent ceramic filler from approximately 30% to approximately 70% by weight of the combined epoxy resin and ceramic filler weight.
Claim 14
Dependent Claim
18 words
A composition according to claim 1, which contains approximately 50% per resin weight of optically transparent ceramic filler.
Claim 15
Dependent Claim
22 words
A composition according to claim 1, which contains optically transparent ceramic fillers with a mean particle size less than about 6.0 microns.
Claim 16
Dependent Claim
21 words
A composition according to claim 1, wherein the optically transparent ceramic filler has a mean particle size of about 3.5 microns.
Claim 17
Dependent Claim
14 words
A composition according to claim 1, wherein the solvent means is an organic solvent.
Claim 18
Dependent Claim
20 words
A composition according to claim 1, which contains from approximately 10% to approximately 70% per solid weight of solvent means.
Claim 19
Dependent Claim
14 words
A composition according to claim 1, wherein the solvent means is methyl amyl ketone.
Claim 20
Dependent Claim
13 words
A composition according to claim 1, wherein the solvent means contains diisobutyl ketone.
Claim 21
Dependent Claim
22 words
A composition according to claim 19, wherein the diisobutyl ketone is present from an effective amount up to 50% total solvent weight.
Claim 22
Dependent Claim
25 words
A composition according to claim 1, wherein the solvent means is approximately 22% total weight methyl amyl ketone and approximately 2% total weight diisobutyl ketone.
Claim 23
Dependent Claim
16 words
A circuit board on which is disposed a photopatterned, polymerized solder mask composition of claim 1.
Claim 24
Dependent Claim
19 words
A circuit board on which is disposed a photopatterned, polymerized dielectric composition of claim 1 for fine line redistribution.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2000-09-15 | 2001-03-17 | 2001-09-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-09-15 | 2005-03-17 | 2005-09-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-09-15 | 2009-03-17 | 2009-09-16 | $7700.00 | Window Closed / Lapsed |