JP2511316B2 - Epoxy resin composition for semiconductor encapsulation - Google Patents

Description

The present invention relates to an epoxy resin composition for encapsulation, which gives a cured product having high heat resistance, low hygroscopicity, low stress and excellent electrical characteristics,
In particular, it relates to an epoxy resin composition for semiconductor encapsulation.

(Prior Art) In recent years, there have been various strict requirements for semiconductor element encapsulation materials along with high integration of semiconductor elements, particularly reduction of internal stress, high glass transition temperature, and resistance to immersion in a solder bath. Crackability is an important issue.

If the internal stress is high, the encapsulating material causes displacement of the aluminum pattern, cracking of the passivation, or cracking of the package itself. In addition, the encapsulating material needs to have a high glass transition temperature in order to maintain the performance of the semiconductor element at high temperature, and when the semiconductor element is immersed in the solder bath, expansion of moisture absorbed In order to prevent solder cracks caused by the above, low hygroscopicity is required, and further, high volume resistivity is required in order to prevent deterioration of electric performance at high temperature.

Generally, a biphenol type epoxy resin is known to have low stress and excellent solder crack resistance, but it can be said that the glass transition temperature is sufficient as compared with epoxy resins derived from other polyvalent phenols. However, there was a problem in volume resistivity at high temperature. for that reason,
In using the biphenol-type epoxy resin as the encapsulant, it has been considered to use a condensate of phenol and hydroxybenzaldehyde as a curing agent, but in this case, heat resistance and electrical characteristics are improved. , The moisture resistance is lowered, and the hang crack is not sufficiently prevented.

(Problem of the Invention) The present invention is to provide an epoxy resin composition for semiconductor encapsulation, which provides a cured product having high heat resistance, low hygroscopicity, low internal stress, and excellent electrical characteristics.

(Means for Solving the Problems) As a result of various studies to solve the above problems, the present inventors have used a specific biphenol-type epoxy resin as an epoxy resin and a cyclic terpene skeleton-containing polyvalent phenol as a curing agent. By using the compound, or a polyvalent phenol compound having a cyclic terpene skeleton obtained by a condensation reaction of the compound and an aldehyde and / or a ketone, the object could be achieved.

That is, the epoxy resin composition for semiconductor encapsulation of the present invention comprises: (Wherein R is a hydrogen atom or a methyl group, R'is a hydrogen atom, a methyl group, an ethyl group, an isopropyl group, a phenyl group, a chloro atom or a bromine atom, and each R'is the same as each other. The average value of m is 0 to 0.
It is a number of 5. ) A bishydroxybiphenyl-based epoxy resin represented by the formula (b), (b) a cyclic terpene skeleton-containing polyvalent phenol compound obtained by addition reaction of one molecule of the cyclic terpene compound with two molecules of the phenol in the presence of an acidic catalyst. And a cyclic terpene skeleton-containing polyvalent phenol compound obtained by further condensing an aldehyde and / or a ketone with the cyclic terpene skeleton-containing polyvalent phenol compound in the presence of an acidic catalyst. A cyclic terpene skeleton-containing polyvalent phenol compound, (c) a curing accelerator, and (d) an inorganic filler are contained as essential components.

Specific examples of the bishydroxybiphenyl-based epoxy resin represented by the general formula (I) in the present invention include:
For example 4,4'-dihydroxybiphenyl, 3,3 ', 5,5'
-Tetramethyl-4,4'-dihydroxybiphenyl, 3,
Obtained by reacting a biphenol derivative such as 3'5,5'-tetraethyl-4,4'-dihydroxybiphenyl, 3,3'5,5'-tetrapropyl-4,4'-dihydroxybiphenyl and epihalohydrin. Epoxy resin is used.

The reaction of the above-mentioned biphenol derivative and epihalohydrin for producing the epoxy resin represented by the general formula (I) can be carried out according to a conventional method. For example, in a reaction vessel equipped with a stirrer, a thermometer and a condenser, a predetermined amount of a biphenol derivative, epihalohydrin such as epiclohydrin (the following description is described as using epichlorohydrin), and isopropyl alcohol are dissolved. Then, the solution is heated to 35 ° C., and then a predetermined amount of sodium hydroxide aqueous solution is added dropwise over 1 hour. During that time, the temperature is gradually raised to 65 ° C. at the end of dropping the aqueous sodium hydroxide solution, and then the temperature is maintained at 65 ° C. for 30 minutes to complete the reaction. Next, the product is washed with water to remove the by-product salt and excess sodium hydroxide, and then excess epichlorohydrin and isopropyl alcohol are distilled off under reduced pressure to obtain a crude epoxy resin. Next, the crude epoxy resin is dissolved in toluene, an aqueous solution of sodium hydroxide is added, and the mixture is stirred at 65 ° C for 1 hour.
Hold the time to carry out the ring closure reaction. After the completion of the ring-closing reaction, sodium phosphate monobasic is added to neutralize the excess sodium hydroxide, followed by washing with water to remove the by-product salt, and then the solvent is completely removed under reduced pressure to obtain the desired epoxy resin (I). Is obtained.

In the epoxy resin composition of the present invention, other epoxy resin can be used in combination with the epoxy resin (I). Examples of other epoxy resins that can be used in combination include phenols such as bisphenol A, bisphenol F, resorcin, hydroquinone, methylresorcin, phenol novolac, cresol novolac, resorcin novolak, and bisphenol A novolac.
Alternatively, an epoxy resin obtained by reacting a polyvalent phenol obtained by a condensation reaction of these phenols with various aldehydes such as hydroxybenzaldehyde, crotonaldehyde, and glyoxal with epihalohydrin can be used. Bishydroxybiphenyl epoxy resin (I) when these other epoxy resins are used in combination
Is 20% by weight or more, preferably 30% by weight or more, based on the total amount of epoxy resin. If the use ratio is low, the effect of the present invention cannot be sufficiently exhibited.

Next, the cyclic terpene skeleton-containing polyvalent phenol compound as the component (b) in the epoxy resin composition of the present invention acts as a curing agent for the epoxy resin.
The polyvalent phenol compound (b) is a cyclic terpene skeleton-containing polyvalent phenol compound obtained by adding two molecules of phenols to one molecule of a cyclic terpene compound in the presence of an acidic catalyst. At least one cyclic terpene skeleton-containing polyvalent compound selected from a cyclic terpene skeleton-containing polyvalent phenol compound obtained by further condensing an aldehyde and / or a ketone with a polyvalent phenol compound-containing compound in the presence of an acidic catalyst. It is a phenol compound.

The cyclic terpene compound as a raw material for producing the cyclic terpene skeleton-containing polyvalent phenol compound may be a monocyclic terpene compound or may be a bicyclic terpene compound, and specific examples thereof include For example:

Dipentene: An optical isomer of limonene.

The other raw materials for producing the cyclic terpene skeleton-containing polyvalent phenol compound include phenols, for example, phenol, cresol, xylenol, propylphenol, nonylphenol, hydroquinone, resorcin, methoxyphenol, glomophenol, and bisphenol. Examples include phenol A and bisphenol F.

The addition reaction between the cyclic terpene compound and the phenols is carried out by adding 1 to 12 mols, preferably 2 to 8 mols, and particularly preferably 2 mols of the phenols to 1 mol of the cyclic terpene compound.
1 to 1 at a temperature of 40 to 160 ° C in the presence of an acid catalyst,
When the reaction is carried out for 0 hours, a polyvalent phenol compound containing a cyclic terpene skeleton is obtained by addition reaction of one molecule of the cyclic terpene compound with two molecules of the phenol.

Examples of the acidic catalyst used in the reaction include hydrochloric acid, sulfuric acid, phosphoric acid, polyphosphoric acid, activated clay, boron trifluoride, and boron trifluoride complex. In the reaction, a solvent may not be used, but a solvent such as aromatic hydrocarbons, alcohols and ethers may be used.

The cyclic terpene skeleton-containing polyvalent phenol compound obtained by such a reaction is, for example, one obtained from α-pinene or limonene and phenol has a structural formula The compound represented by the formula, which is obtained from terpinene and phenol, has the structural formula Is a compound represented by.

The epoxy resin composition of the present invention containing such a polyvalent phenol compound containing a cyclic terpene skeleton as a curing agent can give a cured product having high heat resistance and low hygroscopicity.

The epoxy resin composition of the present invention is a cyclic terpene skeleton-containing polyvalent compound obtained by further subjecting the above-mentioned cyclic terpene skeleton-containing polyvalent phenol compound to a condensation reaction of aldehydes and / or ketones in the presence of an acidic catalyst. A phenol compound may be contained as a curing agent. When the polyvalent phenol compound containing a cyclic terpene skeleton, which has been polymerized by a condensation reaction with such an aldehyde and / or a ketone, and is polyfunctional, is used as a curing agent, the epoxy resin composition of the present invention is It becomes possible to provide a cured product having higher heat resistance.

Examples of aldehydes and ketones used in the condensation reaction include formaldehyde, paraformaldehyde, acetaldehyde, benzaldehyde, hydroxybenzaldehyde, acetone and cyclohexanone.

Further, in the condensation reaction, other phenols can be reacted in combination with the cyclic terpene skeleton-containing polyvalent phenol compound, and as the other phenols used in combination, for example, phenol, cresol, xylenol,
Examples include hydroquinone and bisphenol A.
The amount of the cyclic terpene skeleton-containing polyvalent phenol compound used in combination with other phenols is at least 20% by weight, preferably at least 20% by weight based on the total amount of the phenols used.
It is 40% by weight or more. If the proportion of the polyvalent phenol compound containing a cyclic terpene skeleton used is too low, the resulting epoxy resin composition using the phenol compound containing a cyclic terpene skeleton as a curing agent cannot sufficiently exhibit the intended effect.

The condensation reaction of the polyhydric phenol compound containing a cyclic terpene skeleton with an aldehyde and / or a ketone is carried out in a ratio of 1.0 mol or less, preferably 0.7 mol or less, of the aldehyde and / or ketone with respect to 1 mol of the phenol compound. At a temperature of 40 to 200 ° C. for 1 to 12 hours in the presence of an acidic catalyst. If the proportion of aldehydes and / or ketones in this reaction becomes too large, a high molecular weight product will be formed, and the heat resistance of the cured epoxy resin will improve, but the handleability of the epoxy resin composition will increase due to its high viscosity. Deteriorate.

As the acidic catalyst for the condensation reaction, for example, a mineral acid such as hydrochloric acid or sulfuric acid, an organic acid such as oxalic acid or toluenesulfonic acid, or an acidic acid salt for producing a normal novolak resin such as an organic acid salt showing acidity is used. it can. The amount of the acidic catalyst used is 0.1 to 5 parts by weight based on 100 parts by weight of the phenol compound.

In the condensation reaction, aromatic hydrocarbons,
Inert solvents such as alcohols and ethers can be used.

In the epoxy resin composition of the present invention, the above-mentioned (b) cyclic terpene skeleton-containing polyvalent phenol compound (curing agent),
You may use together another epoxy resin hardening agent. Other curing agents that can be used in combination include compounds having an average of two or more phenolic hydroxyl groups in one molecule, for example, novolak type phenolic resins such as phenol novolak, cresol novolak, resorcinnovolak, bisphenol A novolak, and the like. Condensates of these novolak type phenol resins with formaldehyde, acetaldehyde, hydroxybenzaldehyde, glyoxal and the like can be mentioned.

The mixing ratio of the epoxy resin and the phenol-based curing agent in the epoxy resin composition of the present invention is 10
20 to 200 parts by weight of the total amount of the phenol-based curing agent is based on 0 parts by weight. The ratio is preferably 0.5 to 2.0, preferably about 1 phenolic hydroxyl group in the phenol-based curing agent with respect to one epoxy group in the total epoxy resin.

The curing accelerator (c) in the present invention is (a) an epoxy resin such as a bishydroxybiphenyl epoxy resin,
(B) It accelerates the reaction with a phenol-based curing agent such as a polyvalent phenol compound containing a cyclic terpene skeleton, and accelerates the curing. Examples of the curing accelerator include 2- (dimethylaminomethyl) phenol, 2,4,
Tertiary amines such as 6-tris (dimethylaminomethyl) phenol, benzyldimethylamine, α-methylbenzylamine, 2-methylimidazole, 2-phenylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, Examples thereof include imidazoles such as 2-ethyl-4-methylimidazole and phosphines such as triphenylphosphine. The mixing ratio of the curing accelerator is preferably about 0.02 to 1.0% by weight with respect to the epoxy resin composition.

As the inorganic filler (d) in the present invention, any of those usually used in this type of epoxy resin composition can be used. Specific examples thereof include fused silica powder, crystalline silica powder, quartz glass powder, talc, calcium silicate powder, zirconium silicate powder, alumina powder, calcium carbonate powder, clay powder, barium sulfate powder, and glass fiber. Can be given. These can use 1 type (s) or 2 or more types. Particularly preferred is silica powder.

The compounding amount of the inorganic filler (d) is, depending on the type of the inorganic filler, used in an amount sufficient to impart a desired elastic modulus, linear expansion coefficient, glass transition temperature, etc. to the cured epoxy resin. The amount is usually about 50 to 85% by weight with respect to the resin composition. If the blending amount of the inorganic filler is too small, the linear expansion coefficient becomes large, and if it is too large, the fluidity of the resin composition becomes too low, which makes it difficult to use.

The epoxy resin composition of the present invention may contain various other components, if necessary, in addition to the above-mentioned components. For example, a release agent, a colorant, a coupling agent, a flame retardant and the like can be added. As a release agent,
Examples thereof include natural wax, synthetic wax, higher fatty acid, higher fatty acid metal salt and paraffin, and examples of the colorant include carbon black.
Flame retardants include antimony trioxide, antimony pentoxide,
Examples thereof include phosphoric acid and phosphorus compounds. Further, by using a part of the used epoxy resin as a brominated epoxy resin, the cured product can be made flame-retardant.

(Examples, etc.) The epoxy resin production examples, polyvalent phenol compound production examples, examples and comparative examples will be described in more detail below.

Epoxy resin production example 1 In a reaction vessel equipped with a stirrer, a thermometer and a condenser, 4,4'-bishydroxy-3,3 ', 5,5'-tetramethylbiphenyl 242 g, epichlorohydrin 1295 g, and isopropyl alcohol. 504 g were mixed and dissolved. Next, this solution was heated to 35 ° C., and 190 g of a 48.5% by weight sodium hydroxide aqueous solution was added dropwise over 1 hour.
During that time, the temperature was gradually raised so that the temperature inside the system became 65 ° C. at the end of the dropping. Then, the reaction was carried out by keeping at 65 ° C for 30 minutes. After completion of the reaction, the by-product salt and excess sodium hydroxide were removed by washing with water. Then, excess epichlorohydrin and isopropyl alcohol were distilled off from the product under reduced pressure to obtain a crude epoxy resin.

Then, this crude epoxy resin is mixed with methyl butyl ketone.
Dissolved in 596g, 48.5% by weight sodium hydroxide aqueous solution
12.9g was added and it was made to react at the temperature of 65 degreeC for 1 hour. After the reaction was completed, sodium phosphate monobasic was added to neutralize excess sodium hydroxide, and the product was washed with water to remove by-product salts. The solvent was then completely removed under reduced pressure. The obtained epoxy resin has a polymerization degree (m) in the general formula (I) of 0.1.
This resin has an epoxy equivalent of 185 g / eq. It was. Hereinafter, this epoxy resin referred to as "epoxy resin a ^1".

Epoxy Resin Production Example 2 4,4'-bishydroxy-3, in Production Example 1 above
Instead of 3 ', 5,5'-tetramethylbiphenyl, 4,4'-
An epoxy resin was produced in the same manner as in Production Example 1 except that 186 g of bishydroxybiphenyl was used.

The obtained epoxy resin was a compound having a degree of polymerization (m) of 0.1 in the general formula (I) and an epoxy equivalent of 157 g / eq. Below, this is called "epoxy resin
a ² ”.

Polyvalent phenol compound production example 1 3384 g of phenol and 34 g of boron trifluoride-diethyl ether complex were charged in a three-necked flask having an internal volume of 5 l equipped with a thermometer, a stirrer, and a condenser, and the temperature was 70 to 80 ° C. After 816 g of limonene was added dropwise over 3 hours, the mixture was further stirred at the same temperature for 2 hours for reaction. Then, the product was washed with 1 liter of distilled water three times, then the phenol and by-products were distilled off under reduced pressure, and finally, the mixture was kept at 160 ° C. and 5 mmHg for 1 hour to obtain 1520 g of a cyclic terpene skeleton-containing polycondensate. A valent phenol compound was obtained. The polyvalent phenol compound had a purity of 89% as a result of liquid chromatography analysis. Hereinafter, this is referred to as a “polyvalent phenol compound b ¹ ”.

Polyvalent phenol compound production example 2 In a three-necked flask having an internal volume of 3 liter equipped with a thermometer, a stirrer, and a cooling pipe, 1092 g of the polyvalent phenol compound obtained in the above-mentioned polyvalent phenol compound production example 1, 1000 g of toluene, Then, 5 g of oxalic acid was charged and the temperature was raised to 80 ° C. to uniformly dissolve the oxalic acid. Next, 75 g of a 36% by weight formaldehyde aqueous solution was added dropwise to this solution over 1 hour while maintaining the internal temperature at 80 ° C. After completion of the dropping, the reaction was continued at 80 ° C. for 1 hour.

Next, the temperature of the reaction product was raised, water and toluene were distilled off, and finally, the mixture was kept at 160 ° C. under a reduced pressure of 5 mmHg for 1 hour to completely remove water and toluene. The obtained polymerized polyvalent phenol compound was a yellow solid having a softening point of 126 ° C. Hereinafter, this is referred to as a “polyvalent phenol compound b ² ”.

Polyvalent phenol compound production example 3 Used in the above polyvalent phenol compound production example 2
80 g of benzaldehyde was used in place of 75 g of 36% by weight formaldehyde aqueous solution, and the reaction was carried out in the same manner as in Production Example 2 of polyvalent phenol compound, and post-treatment was conducted in the same manner.
A yellow-red polymerized polyvalent phenol compound having a softening point of 132 ° C. was obtained. Hereinafter referred to as "polyvalent phenol compound b ^3".

Examples 1 to 4 Examples 1 to 3 As shown in Table 1, epoxy resins a ¹ and a ² obtained in Production Examples 1 and 2 of epoxy resin as epoxy resin, bishydroxybiphenyl-based epoxy resin, orthocresol. Using each of the novolak type epoxy resin, each of the polyvalent phenol compounds b ^{1 to} b ³ obtained in the polyvalent phenol compound Production Examples ¹ to ³ , the phenol novolak resin, and the polyfunctional phenol resin as the curing agent, respectively. , Further using brominated epoxy resin and antimony trioxide as a flame retardant, triphenylphosphine as a curing accelerator, silica powder as an inorganic filler, epoxysilane as a surface treatment agent, and carnauba wax as a release agent. Was compounded into each composition.

Then, each composition was mixed with a mixing roll to 90
Each molten mixture obtained by melting and mixing at a temperature of 120 ° C for 5 minutes was taken out as a sheet, cooled and pulverized to obtain each molding material.

Using each of the molding materials, mold with a low-pressure transfer molding machine at a mold temperature of 180 ° C and a molding temperature of 180 seconds, and set the glass transition temperature, moisture absorption rate, volume resistivity, each test piece for bending test measurement, and a simulated element. A sealed 44-pin FPP (flat plastic package) was obtained and post-cured at 180 ° C. for 8 hours. After the post cure, physical properties tests such as glass transition temperature, moisture absorption rate, bending test, volume resistivity and solder heat resistance were conducted.

The results are shown in Table 1, and each of the epoxy resin compositions of Examples 1 to 4 has a low elastic modulus and a low hygroscopicity as compared with the resin compositions of Comparative Examples 1 to 3, and thus the solder crack resistance. It has excellent properties and high volume resistivity,
It has excellent electrical characteristics.

Note to Table 1: * 1 manufactured by Epoxy Resin Manufacturing Example 1 * 2 manufactured by Epoxy Resin Manufacturing Example 2 * 3 ... Yuka Shell Epoxy Co., Ltd. trade name Epicoat 180H65, epoxy Equivalent 203 g / eq. , Softening point 68 ° C. * 4: produced by the polyvalent phenol compound production example 1 * 5: produced by the polyvalent phenol compound production example 2 * 6: by the polyvalent phenol compound production example 3 Manufactured * 7 ... Gunei Chemical Co., Ltd., softening point 85 ° C * 8 ... phenol resin produced from phenol and hydroxybenzaldehyde, softening point 120 ° C, phenol equivalent 98g / eq. * 9 ... oil Chemical Shell Epoxy Co., Ltd. Trade name Epikote 5050, Epoxy equivalent 385g / eq., Bromine content 49% * 10 ... Tatsumori company trade name RD-8 * 11 ... Shin-Etsu Chemical trade name KBM-403 * 12 ... Determined from the transition point of the thermal expansion curve using TMA.

* 13 ... 121 ° C, 100% RH, moisture absorption rate after 200 hours * 14 ... 16 44-pin FPPs absorb moisture at 120 ° C, 100% RH for 100 hours, and then immersed in a 260 ° C solder bath for 10 seconds. The number of cracks was calculated.

(Effects of the Invention) The epoxy resin composition of the present invention is excellent in heat resistance, has low hygroscopicity and low internal stress, and can give a cured product having excellent electrical characteristics, and is excellent for sealing semiconductor elements. .

Claims (1)

(57) [Claims] 1. A general formula: (In the formula, R is a hydrogen atom or a methyl group, R'is a hydrogen atom, a methyl group, an ethyl group, an isopropyl group, a phenyl group, a chloro atom or a bromine atom, and each R'is the same as each other. The average value of m is 0 to 0.
It is a number of 5. ) A bishydroxybiphenyl-based epoxy resin represented by the formula (b), (b) a cyclic terpene skeleton-containing polyvalent phenol compound obtained by addition reaction of one molecule of the cyclic terpene compound with two molecules of the phenol in the presence of an acidic catalyst. And a cyclic terpene skeleton-containing polyvalent phenol compound obtained by further condensing an aldehyde and / or a ketone with the cyclic terpene skeleton-containing polyvalent phenol compound in the presence of an acidic catalyst. An epoxy resin composition for semiconductor encapsulation, comprising the polyvalent phenol compound containing a cyclic terpene skeleton, (c) a curing accelerator, and (d) an inorganic filler as essential components.