Radiation imagery chemistry: process – composition – or product th – Imaging affecting physical property of radiation sensitive... – Radiation sensitive composition or product or process of making
Reexamination Certificate
2001-11-30
2004-08-03
Hamilton, Cynthia (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Imaging affecting physical property of radiation sensitive...
Radiation sensitive composition or product or process of making
C430S018000, C430S014000, C522S101000, C526S247000, C526S284000, C526S279000, C428S414000
Reexamination Certificate
active
06770421
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a photo- or heat-curable resin composition suitable for insulating a printed wiring board and to a multilayer printed wiring board containing an insulating resin layer formed from said photo- or heat-curable resin composition.
BACKGROUND OF THE INVENTION
In recent years, the on-going miniaturization of electronic instruments has led to the development of a multi-level system for printed wiring in order to attain a higher degree of integration of electronic devices and the so-called build-up process which is put into practice by forming an insulating layer and a conductive layer alternately and laminating them together has come into frequent use. And here, high reliability is demanded for the resin materials to be used for insulation. Moreover, it is often the case that a printed wiring board is covered with an insulating layer to protect the surface or the mounted chips.
In the use of insulating materials based on organic resins in multilayer printed wiring boards, however, the organic resins differ greatly in the thermal expansion coefficient from the active parts such as semiconductor devices and the passive parts such as capacitative elements and resistors and, still more, from substrates such as sintered alumina materials, epoxy resins on glass cloth formed by impregnating glass cloth woven from glass fibers with epoxy resins, and silicon wafers; in case a large thermal stress results from the difference in the thermal expansion coefficient between the organic resins and other components, the stress causes cracking and splitting apart of semiconductor devices, capacitative elements, and conductive wirings and the affected devices cease to function normally.
By the way, the use of resin compositions containing epoxy acrylates in printed wiring boards is known from old. For example, Japanese patent publication JP03-205417A (1991) and JP04-355450A (1992) disclose photosensitive resin compositions usable as solder resist or electroless plating resist in the manufacture of printed wiring boards, but they cannot produce a satisfactory effect in the reliability test, typically the cold and heat shock test, in case they are used as permanent resist in printed wiring boards.
On the other hand, JP10-161306A (1998) describes photosensitive resin compositions containing ethylenically unsaturated carboxylic acids wherein 50% by weight or more of ethylene oxide-modified trimethylolpropane triacrylate is incorporated in the ethylenically unsaturated carboxylic acids. However, the photosensitive resin compositions in question are primarily used as etching resist or plating resist and finally peeled off. In consequence, the invention in question differed in the mode of usage from this invention which is concerned with a permanent resist without final peeling off.
Accordingly, an object of this invention is to provide a photo- or heat-curable resin composition which cures into a film of high reliability as tested by the cold and heat shock test which is a typical test for reliability of substrates as a resin composition for forming a resin insulating layer in a wiring board. Another object of this invention is to provide a resin composition which can be processed to yield fine patterns. A further object of this invention is to provide a cured resin which is heat- and solvent-resistant and suitable for use as an interlayer insulating layer in a printed wiring board such as a multilayer printed wiring board.
SUMMARY OF THE INVENTION
The present inventors have conducted intensive studies on a method for preventing the generation of minute cracks which would cause insulation breakdown in the reliability test of the substrate, found that the use of an acrylate having a specific structure, namely that of an alkylene oxide, as an acrylic monomer or oligomer can produce an effect to prevent cracking of an insulating material derived from a resin composition and completed this invention.
A photo- or heat-curable resin composition of this invention comprises 100 parts by weight of (A) unsaturated compound having a structural unit represented by the following general formula (1)
(wherein R is hydrogen or methyl group, A is a group represented by the formula (2), Y is the residue of a polycarboxylic acid or acid anhydride thereof, and n is an integer of 0-3),
(wherein R
1
and R
2
are hydrogen, an alkyl group with 1-5 carbon atoms, or a halogen and X is —CO—, —SO
2
—, —C(CF
3
)
2
—, —Si(CH
3
)
2
—, —CH
2
—, —C(CH
3
)
2
—, —O—, —S—, group represented by the formula (3) or single bond),
10-100 parts by weight of (B) alkylene oxide-modified product of at least one kind of acrylate selected from (meth)acrylates or oligomers thereof, 0-50 parts by weight of (C) compound containing epoxy group and 0-10 parts by weight of (D) photopolymerization initiator or sensitizer. Here, it is preferable that at least a part of the unsaturated compound (A) is an unsaturated compound containing the fluorene skeleton represented by the formula (3) in its structural unit. It is also preferable to incorporate 100 parts by weight or less of at least one kind of other unsaturated compound (E) selected from monomers and oligomers other than the components A and B per 100 parts by weight of the component A.
Furthermore, this invention relates to the cured product obtained from the aforementioned photo- or heat-curable resin composition and to the substrate of a printed wiring board containing at least one layer of said cured product as insulating layer.
DETAILED DESCRIPTION OF THE INVENTION
This invention will be described in detail below.
Unsaturated compounds (A) containing a structural unit represented by the general formula (1) include compounds that contain ethylenic unsaturated bonds and are occur as liquid at normal temperature. Preferable among them are those which are mainly, say 80% by weight or more, composed of unsaturated compounds containing the fluorene skeleton represented by the formula (3) as X.
The component (A) can be prepared, for example, by epoxidizing a bisphenol which contains X at its center, treating the epoxidized bisphenol with (meth)acrylic acid, and then treating the resulting (meth)acrylate with the anhydride of a polybasic acid.
Unsaturated compounds (A) contain 80 mol % or more on the average, preferably 90 mol % or more, of a structural unit represented by the general formula (1) and additionally other structural units such as oligomers with two or more repeating units formed as by-product during the epoxidation of bisphenols. Unsaturated compounds containing a structural unit represented by the general formula (1) may be either oligomers or monomers; they are usually a mixture of compounds differing in the degree of polymerization and A, R, Y, n, R
1
and R
2
need not be identical in a given molecule or unsaturated compound (A) and can vary freely within the defined range.
The procedure for preparing the component (A) is not limited to the aforementioned; for convenience' sake, however, the aforementioned procedure will be explained below.
Bisphenols are typically dihydroxy compounds derived from the general formula (2) by adding H to each terminal O—.
Concrete examples of useful bisphenols are as follows: bis(4-hydroxyphenyl) ketone, bis(4-hydroxy-3,5-dimethylphenyl) ketone and bis(4-hydroxy-3,5-dichlorophenyl) ketone for X=—CO— in the general formula (1) and (2); bis(4-hydroxyphenyl) sulfone, bis(4-hydroxy-3,5-dimethylphenyl) sulfone and bis(4-hydroxy-3,5-dichlorophenyl) sulfone for X=—SO
2
—; 2,2-bis(4-hydroxyphenyl)-hexafluoropropane, 2,2-bis(4-hydroxy-3,5-dimethylphenyl)hexafluoropropane and 2,2-bis(4-hydroxy-3,5-dichlorophenyl)hexafluoropropane for X=—C(CF
3
)
2
—; bis(4-hydroxyphenyl)dimethylsilane, bis(4-hydroxy-3,5-dimethylphenyl)-dimethylsilane and bis(4-hydroxy-3,5-dichlorophenyl)dimethylsilane for X=—Si(CH
3
)
2
—; bis(4-hydroxyphenyl)methane, bis(4-hydroxy-3,5-dibromophenyl)-methane and bis(4-hydroxy-3,5-dichlorophenyl)methane for X=—CH
2
—; 2,2-bis(4-hydroxyphenyl)propane, 2,2-bis(4-hyd
Kawasato Hironobu
Mizuuchi Kazuhiko
Takeuchi Masahiko
Birch & Stewart Kolasch & Birch, LLP
Hamilton Cynthia
Nippon Steel Chemical Co., Ltd
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