Epoxy resin composition for semiconductor encapsulation

The invention relates to an epoxy resin composition for semiconductor encapsulation comprising at least an epoxy resin, hardener, inorganic filler, and accelerator, wherein said epoxy resin is one which is composed of about 20 to about 90 parts by weight of 4,4'-bisphenol F type epoxy resin and about 10 to about 80 parts by weight of either a polyhydric phenolic type epoxy resin which has slightly polar hydrocarbon groups (Z) lying between the phenyl nuclei, or a biphenol type epoxy resin.

FIELD OF THE INVENTION 
The present invention relates to epoxy resin compositions for semiconductor 
encapsulation which are superior in fluidity and yield a cured resin 
superior in soldering crack resistance. 
BACKGROUND OF THE INVENTION 
Epoxy resin compositions are used in various applications such as bonding, 
casting, encapsulation, lamination, molding and coating owing to their 
good handling and curing characteristics. There is a large variety of 
epoxy resins to choose from, depending on the use and curing 
characteristics. 
There have recently been a number of instances in which epoxy resins in 
common use have not achieved the performance required under conditions 
which are more severe than conditions which occurred before. 
For example, the performance of epoxy resin compositions for semiconductor 
encapsulation should be greatly improved in view of the increased degree 
of integration, the enlarged semiconductor element, and the miniaturized 
and thinned package. Another impetus to the enhanced performance comes 
from the fact the surface mount technology for semiconductor devices is 
being put into practice. Since surface mounting is accomplished by dipping 
semiconductor devices directly into a solder bath, the package experiences 
a high stress because of the rapid expansion of absorbed moisture at a 
high temperature. This stress causes cracking of the encapsulant. Thus, if 
an epoxy resin composition for semiconductor encapsulation has to resist 
solder cracking satisfactorily, it should have good heat resistance (or 
high glass transition temperature), low moisture absorption, and low 
stress. 
A common method of reducing moisture absorption and reducing stress (or 
lowering the coefficient of thermal expansion) is to fill the epoxy resin 
with a large amount of inorganic filler such as fused silica powder. This 
is highly effective in the improvement of solder crack resistance. 
However, a highly filled epoxy resin is poor in fluidity at the time of 
molding. Therefore, an epoxy resin for encapsulation should have a low 
melt viscosity. The generally used cresol novolak type epoxy resins do not 
have satisfactorily low moisture absorption and low melt viscosity. 
Much has been studied on the reduction of moisture absorption by epoxy 
resins. A typical means is to introduce a slightly polar group (such as 
dicyclopentane skeleton and xylene skeleton) into the molecule. See 
Japanese Patent Laid-open Nos. 112813/1985 and 201922/1987. It is 
effective to some extent in reducing the moisture absorption but is not 
satisfactorily effective in reducing the melt viscosity. This prevents the 
high filling of an inorganic filler and hence prevents the further 
improvement of solder crack resistance. 
The miniaturized and thinned packages require that epoxy resins for 
encapsulation have higher fluidity than before. Tetramethylbiphenyl-type 
epoxy resins are known to have a low melt viscosity and give a cured 
product having good solder crack resistance owing to its comparatively 
high heat resistance. See Japanese Patent Laid-open No. 47725/1986. 
However, it does not fully meet the recent severe requirements for low 
melt viscosity. 
When it comes to low viscosity, bisphenol A type epoxy resins and bisphenol 
F type epoxy resins are satisfactory; however, they are liquid at normal 
temperature and hence they cannot be used as an encapsulant which has to 
be in the form of powder. In addition, they are also insufficient in low 
moisture absorption and heat resistance. 
SUMMARY OF THE INVENTION 
It is an object of the present invention to provide an epoxy resin 
composition for semiconductor encapsulation which has good fluidity and 
yields a cured product superior in solder crack resistance. 
It has now been found that the object is achieved by employing an epoxy 
resin mixture of a specific bisphenol F type epoxy resin and either a 
specific epoxy resin having a slightly polar hydrocarbon group lying 
between the phenyl nuclei, or a specific bisphenol type epoxy resin. 
Thus, the present invention relates to an epoxy resin composition for 
semiconductor encapsulation containing at least an epoxy resin, hardener, 
inorganic filler, and accelerator, wherein said epoxy resin is one which 
is composed mainly of 20-90 parts by weight of 4,4-bisphenol F type epoxy 
resin represented by the formula (I) 
##STR1## 
wherein m is a numeral of 0-0.5 on average, and 10-80 parts by weight of 
polyhydric phenolic type epoxy resin represented by the formula (II) 
##STR2## 
wherein slightly polar hydrocarbon groups are present between the phenyl 
nuclei, and wherein each R, which may be the same or different from one 
another, denotes a hydrogen atom, a C.sub.1-10 alkyl group, a substituted 
or unsubstituted phenyl group, a substituted or unsubstituted aralkyl 
group, a C.sub.1-10 alkoxyl group or a halogen atom, k denotes an integer 
of 0-4 and its values may be identical with or different from one another, 
G denotes a glycidyl group, Z denotes a C.sub.5-10 divalent hydrocarbon 
group and Z's may be identical with or different from each other; and n is 
a numeral of 0-5 on average, or 10-80 parts by weight of biphenol type 
epoxy resin represented by the formula (III) 
##STR3## 
wherein each R', which may be the same or different from one another 
denotes a hydrogen atom, a C.sub.1-10 alkyl group, a substituted or 
unsubstituted phenyl group, a substituted or unsubstituted aralkyl group, 
a C.sub.1-10 alkoxyl group or halogen atom; and n' is a numeral of 0-0.05 
on average.

DETAILED DESCRIPTION OF THE INVENTION 
The bisphenol F type epoxy resin in common use is a mixture of 2,2'-isomer, 
2,4'-isomer, and 4,4'-isomer. It is a viscous liquid at normal temperature 
because the former two isomers prevent the latter isomer from 
crystallizing. It yields a cured product with low heat resistance. 
By contrast, the 4,4'-bisphenyl F type epoxy resin represented by the 
formula (I) above in the present invention is composed of 4,4'-isomer 
alone. Therefore, it is crystalline (solid) at normal temperature and has 
a low melt viscosity due to the fact that m in the formula (I) has an 
average value of 0-0.5. 
In addition, it yields a cured product with comparatively good heat 
resistance. (It will be referred to as 4,4'-bisphenol F type epoxy resin 
(I) hereinafter.) 
The polyhydric phenolic type epoxy resin represented by the formula (II) in 
the present invention has a slightly polar hydrocarbon group (--Z--) lying 
between the phenyl nuclei. Owing to this structure, it yields a cured 
product which is superior in low moisture absorption and has comparatively 
good heat resistance. (It will be referred to as polyhydric phenolic type 
epoxy resin (II) hereinafter.) 
Further, the biphenol type epoxy resin represented by the formula (III) in 
the present invention is crystalline (solid) at normal temperature. 
Further, since n' in the formula (III) is a numeral of 0-0.5 on average, 
it yields a curable product with low viscosity and a cured product 
comparatively good heat resistance. (It will be referred to as biphenol 
type epoxy resin (III). 
The present invention employs an epoxy resin composed mainly of 20-90 parts 
by weight, preferably 30-80 parts by weight, of 4,4'-bisphenol F type 
epoxy resin (I) and 10-80 parts by weight, preferably 20-70 parts by 
weight, of polyhydric phenolic type epoxy resin (II) or biphenol type 
epoxy resin (III). The epoxy resin composition of the present invention 
has good fluidity and yields a cured product superior equally in low 
moisture absorption, heat resistance, and solder crack resistance. If the 
amount of 4,4'-bisphenol F type epoxy resin (I) exceeds the 
above-specified limit, the epoxy resin composition has good fluidity but 
yields a cured product which is liable to moisture absorption or has 
insufficient heat resistance. If the amount of epoxy resin (II) or (III) 
exceeds the above-specified limit, the epoxy resin composition is poor in 
fluidity although it yields a cured product with low moisture absorption. 
Therefore, the two components should be used in the specified ratio. 
4,4'-bisphenol F type epoxy resin (I) can be produced by the condensation 
reaction of 4,4'-bisphenol F with epihalohydrin in the presence of alkali. 
A typical embodiment of the production process is explained in detail in 
the following. First, 4,4'-bisphenol F is dissolved in epihalohydrin in an 
amount equivalent to 3-20 mol per mol of its phenolic hydroxyl group. To 
the resulting uniform solution is added with stirring an alkali metal 
hydroxide (in the form of solid or aqueous solution) in an amount of 1-2 
mol per mol of the phenolic hydroxyl group. Reaction is carried out at 
atmospheric pressure or under reduced pressure. The reaction system should 
be kept at a prescribed temperature for azeotropic distillation, so that 
it is dehydrated by separating the condensate into water and oil, 
discarding water, and recycling oil. The alkali metal hydroxide should be 
added continuously or intermittently in small portions over 1-8 hours to 
avoid abrupt reactions. Usually, the reaction will take 1-10 hours to 
complete. 
After the reaction is complete, the reaction product is freed of salt (as a 
solid by product) by filtration or water washing. Subsequently, 
epihalohydrin remaining unreacted is distilled way under reduced pressure. 
Thus there is obtained the desired 4,4'-bisphenol F type epoxy resin (I). 
This reaction usually employs epichlorohydrin or epibromohydrin as the 
epihalohydrin and also employs NaOH or KOH as the alkali metal hydroxide. 
Moreover, this reaction may employ a catalyst selected from quaternary 
ammonium salts (such as tetramethylammonium chloride and 
tetraethylammonium bromide), tertiary amines (such as benzylmethylamine 
and 2,4,6-(trisdimethylaminomethyl)phenol), imidazoles (such as 
2-ethyl-4-methylimidazole and 2-phenylimidazole), phosphonium salts (such 
as ethyltriphenylphosphonium iodide), and phosphines (such as 
triphenylphosphine). 
Moreover, this reaction may employ an inert organic solvent selected from 
alcohols (such as ethanol and isopropanol), ketones (such as acetone and 
methyl ethyl ketone), ethers (such as dioxane and ethyleneglycol dimethyl 
ether), and aprotic polar solvents (such as dimethylsulfoxide and 
dimethylformamide). 
The thus obtained 4,4'-bisphenol F type epoxy resin may contain 
saponificable halogen in an excess amount. In such a case, it is possible 
to perform retreatment for further purification. Such treatment may 
consist of dissolving the crude epoxy resin again in an inert organic 
solvent (such as isopropanol), methyl ethyl ketone, methyl isobutyl 
ketone, toluene, xylene, dioxane, propyleneglycol monoethyl ether, and 
dimethylsulfoxide), adding to the solution alkali metal hydroxide (in the 
form of solid or aqueous solution), performing the ring-closing reaction 
again at about 30.degree.-120.degree. C. for 0.5-8 hours, removing excess 
alkali metal hydroxide and byproduct salt by water washing or the like, 
and distilling away the organic solvent under reduced pressure. In this 
way, it is possible to obtain purified 4,4'-bisphenol F type epoxy resin. 
The polyhydric phenolic type epoxy resin (II) is produced by condensation 
reaction (in the presence of alkali) of a polyhydric phenolic resin with 
epihalohydrin, the former being represented by the formula (IV) below, 
with a slightly polar hydrocarbon group lying between the phenyl nuclei. 
##STR4## 
wherein each R which may be the same or different from one another, 
denotes a hydrogen atom, a C.sub.1-10 alkyl group, a substituted or 
unsubstituted phenyl group, a substituted or unsubstituted aralkyl group, 
a C.sub.1-10 alkoxyl group or a halogen atom, k denotes an integer of 0-4 
and its values may be identical with or different from one another, Z 
denotes a C.sub.5-10 divalent hydrocarbon group and Z's may be identical 
with or different from each other and n is a numeral of 0-5 on average. 
The polyhydric phenolic resin represented by the formula (IV) above may be 
produced in various ways. Common methods include addition condensation 
reaction of a phenol compound with a compound containing carbonyl groups, 
addition reaction of a phenol compound with a compound having unsaturated 
bonds, and condensation reaction of a phenol compound with an 
.alpha.-hydroxyalkylbenzene or an .alpha.-alkoxyalkylbenzene. The phenol 
compound may have the same substituent group and/or atom as R in the 
formula (II) above. The addition and/or condensation reaction gives an 
oligomer or a resin. 
Examples of the phenol compound as a raw material include phenol, cresol, 
xylenol, ethylphenol, propylphenol, methoxyphenol, and bromophenol. 
Examples of the compound containing carbonyl groups (which is used to 
oligomerize the phenol compound) include C.sub.5-15 aldehydes and ketones, 
such as benzaldehyde, cyclohexane, acetophenone, and naphthaldehyde. 
Examples of the compound having unsaturated bonds include divinylbenzene, 
diisopropenylbenzene, dicyclopentadiene, norbornene, and terpenes. 
Examples of the .alpha.-hydroxyalkylbenzene or .alpha.-alkoxyalkylbenzene 
include .alpha.,.alpha.-dihydroxy-diisopropylbenzene, 
.alpha.,.alpha.-dimethoxyxylene, and 
.alpha.,.alpha.-dimethoxydiisopropylbenzene. 
The oligomerization may be accomplished in the usual way in the presence of 
an acid catalyst at 20.degree.-200.degree. C. for 1-20 hours. 
Of the thus obtained polyhydric phenolic resins represented by the formula 
(IV) above, dicyclopentadienephenol resin, terpene phenol resin, 
phenolaralkyl resin, and phenolcyclohexanone resin are preferable because 
of their availability and curing characteristics. 
The polyhydric phenolic type epoxy resin (II) used in the present invention 
is prepared by condensation reaction of one or more than one polyhydric 
phenolic resin represented by the formula (IV) above with epihalohydrin in 
the presence of alkali. 
The procedure for this reaction is similar to that employed in the 
production of the 4,4'-bisphenol F type epoxy resin (I). Therefore, its 
detailed description is omitted. 
Incidentally, the polyhydric phenolic type epoxy resin (II) is commercially 
available, and hence it is possible to practice the present invention 
using the commercial product. 
The biphenol type epoxy resin (III) can be produced by condensation 
reaction of 4,4-biphenol with epihalohydrin in the presence of alkali. 
The 4,4'-biphenol as a raw material of the biphenol type epoxy resin (III) 
includes, for example, 4,4'-biphenol, 3,3-dimethyl-4,4'-biphenol, 
3,5-dimethyl-4,4'-biphenol, 3,3-dibutyl-4,4'-biphenol,3,5-dibutyl-4,4'- 
biphenol,3,3'-dibromo-4,4'-biphenol, 
3,3',5,5'-tetramethyl-4,4'-biphenol,3,3'-dimethyl-5,5'-dibutyl-4,4'-biphen 
ol,3,3',5,5'-tetrabutyl-4,4'-biphenol, and 
3,3',5,5'-tetrabromo-4,4'-biphenol. 
The biphenol type epoxy resin (III) used in the present invention can be 
obtained by reacting one or more than one biphenol (mentioned above) with 
epihalohydrin in the same manner as in the production of the 
4,4'-bisphenol F type epoxy resin. 
The biphenol type epoxy resin (III) used in the present invention is 
commercially available under various trade names. 
Thus, the present invention can be practiced by using such commercial 
products. 
According to the present invention, the epoxy resin composition for 
semiconductor encapsulation contains an epoxy resin which is a mixture of 
the 4,4'-bisphenol F type epoxy resin (I) and the epoxy resin (II) or 
(III). This mixture may be prepared by mixing the two epoxy resins which 
have been prepared or purchased separately. Alternatively, the mixture may 
be prepared by mixing 4,4'-bisphenol F with the polyhydric phenolic resin 
of the formula (IV) or a biphenol and reacting the mixture with 
epihalohydrin. 
The mixing ratio of the 4,4'-bisphenol F type epoxy resin (I) and the epoxy 
resin (II) or (III) should be 20-90 parts by weight, preferably 30-80 
parts by weight, for former and 10-80 parts by weight, preferably 20-70 
parts by weight, for the latter. 
According to the present invention, the epoxy resin composition for semi 
conductor encapsulation contains an epoxy resin which is composed mainly 
of the 4,4'-bisphenol F type epoxy resin (I) and the epoxy resin (II) or 
(III) in the above-specified ratio. It should preferably be composed of 
the two epoxy resins (I) and (II), or (I) and (III) alone. However, it may 
contain other epoxy resins. 
Examples of such additional epoxy resins include those epoxy resins 
prepared by condensation reaction of a phenol with epihalohydrin, epoxy 
resins prepared from an amine and epihalohydrin, and epoxy resins prepared 
from a carboxylic acid and epihalohydrin. The phenol include bisphenol A, 
bisphenol AD, hydroquinone, methylhydroquinone, dibutylhydroquinone, 
resorcin, methylresorcin, dihydroxy diphenyl ether, dihydroxynaphthalene, 
phenolnovolak resin, cresolnovolak resin, bisphenol A novolak resin, 
dicyclopentadiene phenolic resin, terpene phenolic resin, phenolaralkyl 
resin, naphtholnovolak resin, brominated bisphenol A, and brominated 
phenolnovolak resin. The phenol also includes polyhydric phenolic resins 
obtained by condensation reaction of a phenol with an aldehyde (such as 
hydroxybenzaldehyde, crotonaldehyde, and glyoxal). 
The amines includes diaminophenylmethane, aminophenol, and xylenediamine. 
This carboxylic acid includes methylhexahydrophthalic acid and dimer acid. 
The additional epoxy resins should be used in an amount less than 100 parts 
by weight, preferably 50 parts by weight, for 100 parts by weight of the 
total amount of the 4,4'-bisphenol F type epoxy resin (I) and the epoxy 
resins (II) or (III). When used in an excess amount, the additional epoxy 
resins have an adverse effect on the present invention. 
According to the present invention, the epoxy resin composition for 
semiconductor encapsulation should be incorporated with a hardener as an 
essential ingredient. No restrictions are imposed on this hardener. 
Commonly used hardeners are satisfactory. 
Examples of the hardener include phenols (such as bisphenol A, bisphenol F, 
bisphenol AD, hydroquinone, resorcin, methylresorcin, biphenol, 
tetramethyl-biphenol, dihydroxynaphthalene, dihydroxy diphenyl ether, 
phenolnovolak resin, cresolnovolak resin, bisphenol A novalak resin, 
cresolnovolak resin, bisphenol A novalak resin, dicyclopentadiene phenolic 
resin, terpene phenolic resin, phenolaralkyl resin, naphtholnovolak resin, 
brominated bisphenol A, and brominated phenolnovalak resin, phenolic 
resins (such as polyhydric phenolic resins obtained by condensation 
reaction of a phenol with an aldehyde such as hydroxybenzaldehyde, 
crotonaldehyde, and glyoxal), active ester compounds (which are obtained 
by esterifying (to form a benzoate of acetate) all or part of the phenolic 
hydroxyl group in the phenol or phenolic resin), acid anhydride (such as 
methyltetra hydrophthalic anhydride, and methyl nadic anhydride), and 
amines (such as diethylenetriamine, isophoro-nediamine, 
diaminophenylmethane, diaminophenylsulfone, and dicyandiamide). 
Of these hardeners, phenols and phenolic resins and active ester compounds 
thereof are preferable from the standpoint of their curing 
characteristics. 
According to the present invention, the epoxy resin composition for 
semiconductor encapsulation should contain a hardener in such an amount 
that the total amount of the reactive groups in the hardener is 0.5-2.0 
mol, preferably 0.7-1.2 mol, per mol of the epoxy groups in all the epoxy 
resins. 
According to the present invention, the epoxy resin composition for 
semiconductor encapsulation should be incorporated with an inorganic 
filler. Examples of the inorganic fillers include fused silica, 
crystalline silica, glass powder, alumina, and calcium carbonate, in the 
form of crushed powder or spherical powder. They may be used alone or in 
combination with one another. Of these examples, fused silica and 
crystalline silica are preferable. The amount of the inorganic filler 
should be 60-95 wt %, preferably 80-93 %, of the total amount of the epoxy 
resin composition. 
According to the present invention, the epoxy resin composition for 
semiconductor encapsulation should be incorporated with an accelerator 
which is a compound to promote the reaction of the epoxy groups in the 
epoxy resin with the active groups in the hardener. 
Examples of the accelerator include phosphine compounds (such as tributyl 
phosphine, triphenyl phosphine, tris(dimethoxyphenyl)phosphine, 
tris(hydroxypropyl)phosphine, and tris(cyanoethyl)phosphine), phosphonium 
tetraphenylborate, methyl-tributyl-phosphonium tetraphenylborate), 
imidazoles (such as 2-methylimidazole, 2-phenylimidazole, 
2-ethyl-4-methyl-imidazole, 2-undecylimidazle, 1-cyanoethyl-2-methyl 
imidazole, 2,4-dicyano-6-2-methylimidazolyl-(1)!-ethyl-S-triazine, and 
2,4-dicyano-62-undecyl-imidazolyl-(1)!-ethyl-S-triazine), imidazolium 
salts (such as 1-cyanoethyl-2-undecylimidazolium trimellitate, 
2-methylimidazolium isocyanurate, 2-ethyl-4-methyl-imidazolium 
tetraphenylborate, and 2-ethyl-1,4-dimethyl-imidazolium 
tetraphenylborate), amines (such as 2,4,6-tris(dimethylaminomethyl)phenol, 
benzyl-dimethylamine, tetramethylbutylguanizine, N-methylpiperazine, and 
2-dimethylamino-1-pyrroline), ammonium salts (such as triethylammonium 
tetraphenyl-borate), diazabicyclo compounds (such as 1,5-diazabi-cyclo 
(5.4.0)-7-undecene, 1,5-diazabicyclo (4.3.0)-5-nonene, and 1,4, 
diazabicyclo (2.2.2)-octane), and diazabicyclo compounds in the form of 
tetraphenyl borate, phenol salt, phenol novalak salt, and 2-ethylhexanoic 
acid salt. 
Preferable among these accelerators are phosphine compounds, imidazole 
compounds, and diazabicyclo compounds and salts thereof. 
These accelerators may be used alone or in combination with one another in 
an amount of 0.1-7 wt %, preferably 1-5 wt %, of the epoxy resins. 
According to the present invention, the epoxy resin composition for 
semiconductor encapsulation may be incorporated with coupling agents, 
plasticizers, pigments, etc. as required. 
It may also be incorporated with a flame retardant such as antimony 
trioxide and phosphoric acid in a proper amount. 
The epoxy resin composition for semiconductor encapsulation in the present 
invention can be advantageously used as an encapsulant for semiconductors 
because of its good fluidity and its ability to yield a cured producing 
good solder crack resistance. 
The invention will be described in more detail with reference to the 
following Examples and Comparative Examples which demonstrate the 
production of epoxy resins and the use of the epoxy resin compositions. 
(1) Production Example of Bisphenol F Type Epoxy Resin 
A 3000 milliliter (ml) three-necked flask equipped with a thermometer, 
stirrer, and condenser was charged with 200 grams (g) of 4,4'-bisphenol F, 
1295 g of epichlorohydrin, and 504 g of isopropyl alcohol. The reactants 
were heated to 35.degree. C. for uniform dissolution. To the solution was 
added dropwise 190 g of 48.5 weight percent (wt %) aqueous solution of 
sodium hydroxide over 1 hour. In this period, the reaction system was 
gradually heated such that it reached 65.degree. C. when the dropwise 
addition was completed. The reaction system as kept at 65.degree. C. for 
30 minutes for reaction. After the reaction was completed, the reaction 
product was washed with water to remove by-product salt and sodium 
hydroxide. The reaction product was freed of excess epichlorohydrin and 
isopropyl alcohol by distillation under reduced pressure. Thus there was 
obtained a crude epoxy resin. 
The crude epoxy resin was dissolved in 400 g of methyl isobutyl ketone. To 
the solution was added 6 g of 48.5 wt % aqueous solution of sodium 
hydroxide. Reaction was carried out at 65.degree. C. for 1 hour. After the 
reaction was completed, sodium primary phosphate was added to neutralize 
excess sodium hydroxide, and the resulting salt (as a by-product) was 
removed by water washing. The reaction product was completely freed of 
methyl isobutyl ketone by distillation under reduced pressure. Thus there 
was obtained the desired 4,4'-bisphenol F type epoxy resin. 
This epoxy resin was a yellowish-white crystalline solid having an epoxy 
equivalent of 164 g/eq. and a melting point of 51.degree. C., with the 
average value of m being 0.1 in the formula (I). 
(a) Production Example of Polyhydric Phenolic Epoxy Resin having Interposed 
Hydrocarbon Groups 
The same procedure as in the production example (1) mentioned above was 
repeated to give an epoxy resin, except that the 4,4'-bisphenol F (200 g) 
was replaced by 360 g of dicyclopentadiene phenolic resin (DCP-5000 from 
Mitsui Toatsu Chemicals, Inc.). 
The resulting epoxy resin was a yellowish red solid having an epoxy 
equivalent of 255 g/eq. and softening point of 62.degree. C., as 
represented by the formula (IT) in which R is a hydrogen atom, Z is a 
group represented by the formula below, k is 0, and n is 1.2. 
##STR5## 
(b) Production Example of Polyhydric Phenolic Epoxy Resin having 
Interposed Hydrocarbon Groups 
The same procedure as in the production example (1) mentioned above was 
repeated to give an epoxy resin, except that the 4,4'-biphenol F (200 g) 
was replaced by 350 g of phenolaralkyl resin (Milex XL225LL from Mitsui 
Toatsu Chemicals, Inc.). 
The resulting epoxy resin was a yellowish red solid having an epoxy 
equivalent of 252 g/eq. and a softening point of 64.degree. C. as 
represented by the formula (II) in which R is a hydrogen atom, Z is a 
group represented by the formula below, k is 0 and n is 2.1. 
##STR6## 
(c) Production Example of Polyhydric Phenolic Epoxy Resin having 
Interposed Hydrocarbon Groups 
The same procedure as in the production example (1) mentioned above was 
repeated to give an epoxy resin, except that the 4,4'-bisphenol F (200 g) 
was replaced by 330 g of terpenephenolic resin (YP-90 from Yasuhara 
Chemical Co., Ltd.). 
The resulting epoxy resin was a yellowish red solid having an epoxy 
equivalent of 233 g/eq. and a softening point of 60.degree. C., as 
represented by the formula (II) in which R is a hydrogen atom, Z is a 
group represented by the formula below, k is 0, and n is 0.1. 
##STR7## 
EXAMPLES 1 TO 5 AND COMATIVE EXAMPLES 1 TO 3 
An epoxy resin composition was prepared from epoxy resins and auxiliaries 
shown below. 
Epoxy resins: the epoxy resin obtained in the production example 1, the 
epoxy resin obtained in any of the production examples (a) to (c), cresol 
novolak type epoxy resin, and brominated epoxy resin. 
Hardener: commercial phenol novolak resin (A) or commercial terpene phenol 
novolak resin (B) 
Organic filler: commercial fused silica powder of crushed type (82 wt % of 
the entire composition in Examples 1 to 5 and Comparative Example 1; and 
75 wt % of the entire composition in Comparative Examples 2 and 3) 
Accelerator: triphenylphosphine 
Flame retardant: antimony trioxide 
Surface treating agent for inorganic filler: commercial epoxy silane 
Mould release: carnauba wax 
The resulting composition was kneaded at 70.degree.-130.degree. C. for 5 
minutes using a mixing roll. The molten mixture was made into a shoot, 
which was subsequently crushed. Thus there was obtained a molding 
compound. 
The molding compound was molded into a specimen by low pressure transfer 
molding, with the die temperature being 180.degree. C. and the molding 
time being 180 seconds. The specimen was postcured at 180.degree. C. for 8 
hours. The molding material was also tested for spiral flow. 
The postcured specimen and spiral flow test piece were tested for solder 
crack resistance, moisture absorption and glass transition point. The 
results are shown in Table 1. It is noted that the molding compounds in 
Examples 1 to 5 are superior to those in Comparative Examples 1 to 3 in 
both fluidity (spiral flow) and solder crack resistance. 
TABLE 1 
__________________________________________________________________________ 
Example No. (Comparative Example No.) 
1 2 3 4 5 (1) (2) (3) 
__________________________________________________________________________ 
Formulation of 
Epoxy resin (I) from 
80 30 70 60 50 100 -- -- 
epoxy resin 
production example (1) 
composition 
Epoxy resin (II) from 
(a) (a) (a) (b) (c) -- (a) -- 
(parts by weight) 
production example (a), 
20 70 30 20 50 100 
(b), or (c) 
Cresol novolak type 
-- -- -- 20 -- -- -- 100 
epoxy resin.sup.1 
Brominated epoxy 
10 10 10 10 10 10 10 10 
resin.sup.2 
Hardener (amount) 
A.sup.3 
A.sup.3 
B.sup.4 
A.sup.3 
B.sup.4 
A.sup.3 
A.sup.3 
A.sup.3 
(61) 
(50) 
(100) 
(59) 
(95) 
(65) 
(43) 
(53) 
Inorganic filler.sup.5 
838 788 1016 
829 993 856 498 528 
Tripenyl-phosphine 
1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 
Antimony trioxide 
10 10 10 10 10 10 10 10 
Carnauba wax 
1 1 1 1 1 1 1 1 
Epoxy silane.sup.6 
1 1 1 1 1 1 1 1 
Fluidity, spiral flow at 180.degree. C., (cm) 
88 80 85 84 84 96 71 61 
Properties of 
Solder crack resistance.sup.7 
0/16 
0/16 
0/16 
0/16 
0/16 
8/16 
10/16 
15/16 
cured product 
Moisture absorption 
0.30 
0.28 
0.27 
0.30 
0.28 
0.34 
0.40 
0.44 
(%).sup.8 
Glass transition point 
130 139 142 131 147 118 141 154 
(.degree.C.).sup.9 
__________________________________________________________________________ 
Notes to Table 1 
.sup.1 ocresol novolaks type epoxy resin (Epikote 180H65, epoxy equivalen 
= 205, from Yuka Shell Epoxy K.K.) 
.sup.2 brominated bisphenol A type epoxy resin (Epikote 5050, epoxy 
equivalent = 385, bromine content = 49%, from Yuka Shell Epoxy K.K.). 
.sup.3 A: phenol novolak resin (hydroxyl equivalent = 103, softening poin 
= 85.degree. C., from Gun'ei Kagaku Co., Ltd.) 
.sup.4 B: terpene phenol novolak resin (Epikure MP402, hydroxyl equivalen 
= 175, softening point = 130.degree. C., from Yuka Shell Epoxy K.K.) 
.sup.5 Fused silica powder of crushed type (RD8, from Tatsumori Co., Ltd. 
.sup.6 KBM403, from ShinEtsu Chemical Co., Ltd. 
.sup.7 16 specimens (44pin FPP) which had been allowed to absorb moisture 
at 85.degree. C. and 85% RH for 300 hours were dipped in a solder bath at 
260.degree. C. for 10 seconds. The number of cracked specimens was 
counted. 
.sup.8 moisture absorption at 85.degree. C. and 86% RH for 300 hours. 
.sup.9 obtained by TMA from the transition point on the thermal expansion 
curve. 
It is apparent from Table 1 that the compositions in Examples are superior 
in fluidity to those in Comparative Examples and the cured products from 
the former are superior in moisture absorption, solder crack resistance, 
and heat resistance (in terms of glass transition point) to those from the 
latter. 
(2) Production Example of Epoxy Resin 
The same procedure as in the production example (1) mentioned above was 
repeated to give a mixture of 4,4'-bisphenol F type epoxy resin and 
biphenol type epoxy resin, except that the 4,4'-bisphenol F (200 g) was 
replaced by a mixture of 4,4'-bisphenol F (160 g) and 4,4'-biphenol (40 
g). 
The resulting epoxy resin was a yellowish white crystalline solid having an 
epoxy equivalent of 163 g/eq. It was a mixture of 80 wt % 4,4'-bisphenol F 
type epoxy resin represented by the formula (1) in which m has a value of 
0.1 and 20 wt % biphenol type epoxy resin represented by the formula (III) 
in which n has a value of 0.1. 
EXAMPLES 6 TO 10 AND COMATIVE EXAMPLES 4 TO 6 
An epoxy resin composition was prepared from epoxy resins and auxiliaries 
as follows according to the formulation shown in Table 2. 
Epoxy resins: the epoxy resin obtained in the production example (1), the 
epoxy resin obtained in the production example (2), commercial biphenol 
type epoxy resin (A or B) cresol novolak type epoxy resin, and brominated 
epoxy resin. 
Hardener: commercial phenol novolak resin (C) or commercial terpene phenol 
novolak resin (D) 
Inorganic filler: commercial fused silica powder of crushed type (82 wt % 
of the entire composition in Examples 6 to 10 and Comparative Examples 4 
and 5; and 75 wt % of the entire composition in Comparative Example 6) 
Accelerator: triphenylphosphine 
Flame retardant: antimony trioxide 
Surface treating agent for inorganic filler: commercial epoxy silane 
Mould release: carnauba wax 
The resulting composition was kneaded at 70.degree.-130.degree. C. for 5 
minutes using a mixing roll. The molten mixture was made into a sheet, 
which was subsequently crushed. Thus there was obtained a moulding 
compound. 
The moulding compound was moulded into a specimen by low-pressure transfer 
moulding, with the die temperature being 180.degree. C. and the moulding 
time being 180 seconds. The specimen was postcured at 180.degree. C. for 8 
hours. The moulding material was also tested for spiral flow. 
The post-cured specimen and spiral flow test piece were tested for solder 
crack resistance, moisture absorption, and glass transition point. The 
results are shown in Table 2. It is noted that the moulding compounds in 
Examples 6 to 10 are superior to those in Comparative Examples 4 to 6 in 
both fluidity (spiral flow) and solder crack resistance. 
TABLE 2 
__________________________________________________________________________ 
Example No. (Comparative Example No.) 
6 7 8 9 10 (4) (5) (6) 
__________________________________________________________________________ 
Formulation of 
Epoxy resin (I) from 
80 30 70 -- -- 100 -- -- 
epoxy resin 
production example (1) 
composition 
Epoxy resin (II) from 
-- -- -- 80 100 -- -- -- 
(parts by weight) 
production example (2) 
Biphenol type epoxy 
A.sup.1 
A.sup.1 
B.sup.2 
-- -- -- A.sup.1 
-- 
resin (amount) 
(20) 
(70) 
(30) (100) 
Cresol novolak type 
-- -- -- 20 -- -- -- 100 
epoxy resin.sup.3 
Brominated epoxy 
10 10 10 10 10 10 10 10 
resin.sup.4 
Hardener (amount) 
C.sup.5 
C.sup.5 
C.sup.5 
C.sup.5 
D.sup.6 
C.sup.5 
C.sup.5 
C.sup.5 
(64) 
(59) 
(65) 
(63) 
(112) 
(65) 
(56) 
(53) 
Inorganic filler.sup.7 
852 829 856 847 1070 
856 815 528 
Tripenylphosphine 
1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 
Antimony trioxide 
10 10 10 10 10 10 10 10 
Carnauba wax 
1 1 1 1 1 1 1 1 
Epoxy silane.sup.8 
1 1 1 1 1 1 1 1 
Fluidity, spiral flow at 180.degree. C., (cm) 
88 81 87 86 87 96 64 61 
Properties of 
Solder crack resistance.sup.9 
0/16 
0/16 
0/16 
0/16 
0/16 
8/16 
2/16 
15/16 
cured product 
Moisture absorption 
0.30 
0.29 
0.30 
0.30 
0.27 
0.34 
0.28 
0.44 
(%).sup.10 
Glass transition point 
128 132 137 135 152 118 132 154 
(.degree.C.).sup.11 
__________________________________________________________________________ 
Notes to Table 2 
.sup.1 epoxy resin derived from tetramethylbiphenol (Epikote YX4000H, 
epoxy equivalent = 193, with the value of n in the formula (III) being 
0.2, from Yuka Shell Epoxy K.K.) 
.sup.2 epoxy resin derived from biphenol and tetramethylbiphenol (Epikote 
YL6121H, epoxy equivalent = 173, with the value of n in the formula (III) 
being 0.1, from Yuka Shell Epoxy K.K.) 
.sup.3 ocresol novolak type epoxy resin (Epikote 180H65, epoxy equivalent 
= 205, from Yuka Shell Epoxy K.K.) 
.sup.4 brominated bisphenol A type epoxy resin (Epikote 5050, epoxy 
equivalent = 385, bromine content = 49% from Yuka Shell Epoxy K.K.) 
.sup.5 phenol novolak resin (hydroxyl equivalent = 103, softening point = 
85.degree. C., from Gun'ei Kagaku Co., Ltd.) 
.sup.6 terpene phenol novolak resin (Epikure MP402, hydroxyl equivalent = 
175, softening point = 130.degree. C., from Yuka Shell Epoxy K.K.) 
.sup.7 Fused silica powder of crushed type (RD8, from Tatsumori Co., Ltd. 
.sup.8 KBM403, from Shin Etsu Chemical Co., Ltd. 
.sup.9 16 specimens (44pin FPP) which had been allowed to absorb moisture 
at 85.degree. C. and 85% RH for 300 hours were dipped in a solder bath at 
260.degree. C. for 10 seconds. The number of cracked specimens was 
counted. 
.sup.10 moisture absorption at 85.degree. C. and 86% RH for 300 hours. 
.sup.11 obtained by TMA from the transition point on the thermal expansio 
curve. 
It is apparent from Table 2 that the compositions in Examples are superior 
in fluidity to those in Comparative Examples and the cured products from 
the former are superior in moisture absorption, solder crack resistance, 
and heat resistance (in terms of glass transition point) to those from the 
latter.