Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Compositions to be polymerized by wave energy wherein said...
Reexamination Certificate
2000-01-11
2002-12-24
Berman, Susan W. (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Compositions to be polymerized by wave energy wherein said...
C522S015000, C522S024000, C522S025000, C522S063000, C522S071000, C522S083000, C522S168000, C522S170000, C523S300000, C524S413000, C524S425000, C524S430000, C524S432000, C524S433000, C524S464000, C524S786000, C524S789000, C524S779000, C524S788000
Reexamination Certificate
active
06498200
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a resin composition which cures by cationic polymerization, more specifically, to a resin composition which is useful for an encapsulating agent of a semiconductor, an electric insulating material, a sealing agent or a binder. The present invention also relates to a semiconductor package encapsulated by the resin composition and a circuit board mounted thereon such a semiconductor.
2. Prior Art
An epoxy compound or an oxetane compound have an oxygen-containing ring structure and cured to form a resinous polymer in the presence of a curing agent and/or a curing catalyst under heating or irradiation of light by utilizing their reactivity, and have been widely used as an encapsulating agent of a semiconductor or an electric insulating material.
As a curing agent of these compounds, a method of using a phenol-novolak compound has been known, but in this method, the reaction rate is relatively slow. Also, in the method an amino compound such as a polyamine or an acid anhydride compound such as pyromellitic anhydride is used.
It has been known that an oxirane compound or an oxetane compound is subjected to heat polymerization or photopolymerization by using a cationic polymerization catalyst. In the reaction system in which such a polymerization catalyst is formulated is stable at normal temperature and a high reaction rate can be obtained by heating or photoirradiation so that it has been attracted attention as a latent catalyst. As an onium salt, there has been generally used an iodonium salt, a sulfonium salt, a phosphonium salt, etc.
The onium salt is an acidic substance, and when a cured resin obtained by using the same is subjected to humidity resistance test, an extracted liquid shows an acidic property. This is because an onium salt remained in the resin after curing is liberated from the resin in the presence of moisture, and thus, when such a resin is used for encapsulation or electric insulation of electronic parts, the electronic parts or parts in the vicinity thereof are corroded or defected.
On the other hand, if an alkaline substance such as an amine, etc. is used in a composition containing an oxirane compound or an oxetane compound and an onium compound in combination to neutralize the acidic substance, cationic species of the onium salt are broken so that deactivation of a catalyst and inhibition of curing based thereon are generated.
Also, when such an onium salt is used as a curing catalyst, a high reaction rate can be obtained. However, in these days, it has been earnestly desired to develop a reaction system which provides a high reaction rate by using an onium salt catalyst which does not cause large effect on hygiene and environment.
SUMMARY OF THE INVENTION
An object of the present invention is to solve the conventional problems and to provide a cationically polymerizable resin composition which causes no curing obstruction, cures rapidly, excellent in preservation stability and does not cause increase in electroconductivity of an extracted water or corrosion.
The present inventors have earnestly studied to accomplish the above objects and as a result, they have found that the above objects can be accomplished by using an oxirane ring and/or an oxetane ring-containing compound in combination with a cationically polymerizable catalyst and an organic peroxide, and further using an alkaline filler as at least a part of a filler.
That is, the present invention relates to a cationically polymerizable resin composition which comprises
(A) a compound containing at least one ring selected from the group consisting of an oxirane ring and an oxetane ring;
(B) an onium salt;
(C) an organic peroxide; and
(D) an alkaline filler except for a hydroxide.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Component (A) to be used in the present invention is a compound having at least one oxirane ring and/or oxetane ring, and it may be a single species or two or more of mixtures. It is particularly preferred that Component (A) itself is a liquid at normal temperature, or Component (A) which is a solid at normal temperature is dissolved by a solvent or used in combination with a liquid state compound containing an oxirane ring to show a liquid state as a whole at normal temperature since it is easy in encapsulating operation or formation. It is more preferred that Component itself is a liquid state at normal temperature. Incidentally, a liquid state at normal temperature herein mentioned means a material which show fluidity at 25 to 40° C.
As a compound having an oxirane ring, there may be used a low molecular weight or high molecular weight compound having more than two oxirane rings in the molecule which is generally so-called an epoxy resin, a reactive diluent having one or more oxirane ring in the molecule and a silane compound or a siloxane compound each having an oxirane ring in the molecule. As the epoxy resin, there may be exemplified by a bisphenol A type epoxy resin, a brominated bisphenol A type epoxy resin, a bisphenol F type epoxy resin, a novolak type epoxy resin, an alicyclic epoxy resin, a biphenyl type epoxy resin, an ether type or a polyether type epoxy resin, an oxirane ring-containing polybutadiene, a silicone epoxy copolymerized resin, etc.
As an epoxy resin which is a liquid state at normal temperature, there may be mentioned a bisphenol A type epoxy resin having an average molecular weight of about 400 or less; a branched polyfunctional bisphenol A type epoxy resin such as p-glycidylphenyldimethyltolyl bisphenol A glycidyl ether represented by the following formula:
a bisphenol F type epoxy resin; a phenol novolak type epoxy resin having an average molecular weight of about 570 or less; alicyclic epoxy resin such as vinyl(3,4-cyclohexene)dioxide(3,4-epoxycyclohexyl)methyl 3,4-epoxycyclohexylcarboxylate, bis(3,4-epoxy-6-methylcyclohexyl-methyl)adipate, 2-(3,4-epoxycyclohexyl)5,1-spiro(3,4-epoxycyclohexyl)-m-dioxane, etc.; a glycidyl ester type epoxy resin such as diglycidyl hexahydrophthalate, diglycidyl 3-methylhexahydrophthalate, diglycidyl hexahydroterephthalate, etc.; a glycidyl amine type epoxy resin such as diglycidylaniline, diglycidyltoluidine, triglycidyl-p-aminophenol, tetraglycidyl-m-xylylene diamine, tetraglycidylbis(aminomethyl)cyclohexane, etc.; and a hydantoin type epoxy resin such as 1,3-diglycidyl-5-methyl-5-ethylhydantoin, etc., and an alicyclic epoxy resin is preferred since high curing rate can be obtained.
Also, an epoxy resin which is a solid or having a super high viscosity at normal temperature may be used in combination with the epoxy resin which is a liquid state at normal temperature. Such an epoxy resin may be exemplified by a bisphenol A type epoxy resin with a high nmolecular weight, diglycidyl biphenyl, a novolak epoxy resin, a tetrabromo bisphenol A type epoxy resin, etc.
The reactive diluent is a compound having one or more oxirane rings in the molecule and having a relatively low viscosity at normal temperature, and depending on the purpose, it may have other polymerizable functional groups than the oxirane ring, such as an alkenyl group including vinyl, allyl, etc.; or an unsaturated carboxylic acid residue including acryloyl, methacrylol, etc. As the reactive diluent as mentioned above, there may be exemplified by a monoepoxide compound such as n-butyl glycidyl ether, 2-ethylhexyl glycidyl ether, phenyl glycidyl ether, cresyl glycidyl ether, p-s-butylphenyl glycidyl ether, styrene oxide, &agr;-pinene oxide, etc.; a monoepoxide having other functional groups such as allyl glycidyl ether, glycidyl methacrylate, 1-vinyl-3,4-epoxycyclohexane, etc.; a diepoxide compound such as (poly)ethyleneglycol diglycidyl ether, (poly)propyleneglycol diglycidyl ether, butanediol glycidyl ether, neopentylglycol diglycidyl ether, etc.; and a triepoxide compound such as trimethylolpropane triglycidyl ether, glycerin triglycidyl ether, etc.
As the silane compound having an oxirane ring, there may be exemplified by 3-glycidoxypropyl trimethoxysilane, 3-glycidoxyprop
Kondo Hisao
Suzuki Ken'ichi
Suzuki Osamu
Yoshii Haruyuki
Berman Susan W.
Frishauf Holtz Goodman & Chick P.C.
Namics Corporation
LandOfFree
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