JP2001253930A - Epoxy resin composition and semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an epoxy resin composition for semiconductor sealing use, exhibiting small warpage in solder treatment, having a low elastic modulus, high adhesivity and excellent soldering crack resistance and moldability. SOLUTION: The epoxy resin composition for semiconductor sealing use contains an epoxy resin (A) produced by mixing (a) a polyfunctional phenolic resin with (b) 4,4-dihydroxy-3,3',5,5'-tetramethylbiphenyl to effect the glycidyl etherification, a phenol aralkyl resin hardener having phenylene and diphenylene skeletons, an inorganic filler and a cure accelerator as essential components. The weight ratio (a/b) is 1-19, the softening point of the epoxy resin (A) is 70-120 deg.C, the equivalent ratio of the phenolic hydroxyl group of the total phenolic resin hardener to the epoxy group of the total epoxy resin is 0.5-2.0 and the content of the inorganic filler is 250-1,400 pts.wt. based on 100 pts.wt. of the sum of the total epoxy resin and the total phenolic resin hardener.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an epoxy resin composition for semiconductor encapsulation, which has a small warpage during soldering in an area mounting type semiconductor device, has excellent solder crack resistance, and has excellent moldability. The present invention relates to a semiconductor device used.

[0002]

2. Description of the Related Art In recent years, in the market trend of miniaturization, weight reduction and high functionality of electronic devices, high integration of semiconductor elements has been progressing year by year, and surface mounting of semiconductor devices has been promoted. Area-mounted semiconductor devices have been developed and have begun to shift from semiconductor devices having conventional structures. A ball grid array (hereinafter, referred to as BGA) or a chip size package (hereinafter, referred to as CSP) pursuing further miniaturization is typical of the area mounting type semiconductor device. The surface-mount type semiconductor device represented by is developed to meet the demand for multi-pin and high-speed which is approaching the limit. The structure is as follows: a bismaleimide-triazine (hereinafter referred to as BT) resin / copper foil circuit board as a rigid circuit board or a polyimide resin film / copper foil circuit board as a flexible circuit board, and a semiconductor An element is mounted, and only the semiconductor element mounting surface, that is, one side of the substrate is molded and sealed with a resin composition or the like. Also, on the surface opposite to the semiconductor element mounting surface of the substrate, solder balls are formed two-dimensionally in parallel, and are characterized in that they are joined to the substrate on which the semiconductor device is mounted. Further, as a substrate on which semiconductor elements are mounted,
In addition to the organic substrate, a structure using a metal substrate such as a lead frame has been devised.

The structure of these area-mounted semiconductor devices is as follows:
In many cases, only the semiconductor element mounting surface of the substrate is sealed with the epoxy resin composition, and the solder ball forming surface is not sealed. Inside, a board-on-chip (hereinafter, BOC)
In some cases, a sealing resin layer is also formed on the surface on which the solder balls are formed, but this sealing resin layer is thinner than the sealing resin layer on the semiconductor element mounting surface. For this reason, thermal expansion and expansion between the organic substrate or metal substrate and the cured product of the resin composition
In these semiconductor devices, warpage is likely to occur immediately after molding due to mismatch of thermal shrinkage or influence of curing shrinkage during molding and curing of the resin composition. When soldering is performed on a substrate on which these semiconductor devices are mounted, a heating step of 200 ° C. or more is performed. At this time, the semiconductor devices are warped, and many solder balls are not flattened. Is raised from the substrate on which the semiconductor chip is mounted, and the reliability of the electrical connection decreases.

In these area-mounted semiconductor devices,
In order to reduce the warpage, two methods of bringing the linear expansion coefficient of the substrate close to the linear expansion coefficient of the cured product of the resin composition and reducing the curing shrinkage of the resin composition are important.
As the substrate, in the case of an organic substrate, resins having a high glass transition temperature (hereinafter referred to as Tg) such as BT resin and polyimide resin are widely used. Has a high Tg. Therefore, during the cooling process from the molding temperature to room temperature, the α
It contracts only in the region of 1. Therefore, if the cured product of the resin composition also has a high Tg, α1 is the same as that of the substrate, and if the curing shrinkage is zero, the warpage is considered to be almost zero. For this reason, a method has been proposed in which Tg is increased by a combination of a triphenolmethane-type epoxy resin and a triphenolmethane-type phenol resin, and α1 is adjusted by the blending amount of the inorganic filler.

When soldering is performed by means such as infrared reflow, vapor phase soldering, and solder immersion,
Due to moisture absorption from the cured product of the resin composition and the organic substrate,
Cracks may occur in the semiconductor device due to stress caused by the rapid vaporization of moisture present inside the semiconductor device at high temperatures,
Separation may occur at the interface between the element mounting surface of the substrate and the cured product of the resin composition, and the cured product has higher strength, lower stress,
Along with low moisture absorption, high adhesion to the substrate is also required. In conventional area-mounted semiconductor devices such as BGA and CSP,
In order to reduce warpage, resin compositions containing a triphenolmethane-type epoxy resin and a triphenolmethane-type phenol resin as resin components have been used. The cured product of this resin composition has a high Tg, curability, and properties having excellent flexural strength when heated, but has a high moisture absorption rate of the cured product and a relatively high melt viscosity of the resin composition. Therefore, there is a limit to increasing the amount of the inorganic filler, and insufficient moisture absorption is required, and there is a problem in solder crack resistance.

On the other hand, in a conventional surface mount type semiconductor device such as QFP or SOP, a crystalline epoxy resin typified by a biphenyl type epoxy resin is used to prevent cracks at the time of solder mounting and peeling at the interface of each material. Although it is used, there is a problem that the bending strength at the time of heating is low and the curing is slow as compared with a cured product of a resin composition using a triphenolmethane epoxy resin. Therefore, in order to obtain a resin composition having a small warpage, excellent curability, excellent bending strength when heated, and low hygroscopicity, low elastic modulus, high adhesion, and excellent solder crack resistance, a triphenolmethane epoxy resin is used. In order to take advantage of the characteristics of crystalline epoxy resin, triphenolmethane epoxy resin can be used even when both epoxy resins are used together in an appropriate amount during the production of the resin composition, or when both epoxy resins are melt-mixed in advance. Warpage is small when
It is possible to combine the characteristics of excellent curability and bending strength under heat with the characteristics of low moisture absorption, low elastic modulus, high adhesion and excellent solder crack resistance when using a crystalline epoxy resin. Not enough.

[0007]

SUMMARY OF THE INVENTION The present invention relates to a semiconductor device having a small warpage, a low elastic modulus, a high adhesion, an excellent solder crack resistance and an excellent moldability at the time of soldering in an area mounting type semiconductor device. It is an object of the present invention to provide a sealing epoxy resin composition and a semiconductor device using the same.

[0008]

The present invention provides (A) a precursor of a polyfunctional phenol resin (a) represented by the general formula (1) and / or the general formula (2) and a crystalline epoxy resin. An epoxy resin mixed with phenol (b) and glycidyl etherified, (B) a phenol resin curing agent represented by the general formula (3), (C) an inorganic filler, and (D) a curing accelerator are essential components. , (A) and (b) weight ratio (a /
b) is 1 to 19, and the softening point of the epoxy resin (A) is 70
１２０120 ° C., the equivalent ratio of the phenolic hydroxyl groups of all phenolic resin curing agents to the epoxy groups of all epoxy resins is 0.5 to 2.0, and the content of inorganic filler is all epoxy resin and all phenolic resin. An epoxy resin composition for semiconductor encapsulation, which is 250 to 1400 parts by weight per 100 parts by weight of the total amount of the curing agent.

Embedded image (R1 and R2 are alkyl groups having 1 to 5 carbon atoms, which may be the same or different from each other; a = 0 to 0)
Integer of 3, integer of b = 0 to 4, k is an average value of 1 to 10
Positive number of

[0009]

Embedded image (R3 is an alkyl group having 1 to 5 carbon atoms, which may be the same or different from each other; c = an integer of 0 to 4)

[0010]

Embedded image (R4 and R5 are alkyl groups having 1 to 5 carbon atoms, which may be the same or different. D = 0 to 0
An integer of 3; an integer of e = 1 to 4; m and n are average values, each of which is a positive number of 1 to 10). In addition, the warpage of the area mounting type semiconductor device during the soldering process is small, and the solder cracking resistance is excellent.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The polyfunctional phenol resin (a) represented by the general formula (1) and / or the general formula (2) used in the present invention and a phenol (b) which is a precursor of a crystalline epoxy resin are used. The epoxy resin (A) obtained by glycidyl etherifying a mixture having a weight ratio (a / b) of 1 to 19 (hereinafter, referred to as a mixed polyphenol) has a low viscosity derived from a crystalline epoxy resin. This makes it possible to increase the filling of the inorganic filler, and thereby reduce the moisture absorption of the cured product of the resin composition, so that the Tg of the cured product of the resin composition hardly decreases, and the resin composition using a polyfunctional epoxy resin is used. Compared with the bending strength of the cured product when heated, it has a low elastic modulus,
The curability has the same characteristics. The epoxy resin (A) obtained by this method improves the curing reactivity, which is a problem when using a crystalline epoxy resin, by making the polyfunctional epoxy resin and the crystalline epoxy resin more uniform. It is considered something. Therefore, a semiconductor device using the resin composition of the present invention can achieve high reliability even under soldering during mounting.

The polyfunctional phenolic resins represented by the general formulas (1) and (2) include, for example, the formulas (7), (8), (9), (10) and (11). However, the polyfunctional phenol resins of the formulas (7) and (10) are preferable from the viewpoints of availability, performance, raw material price and the like.

Embedded image (K is an average value and a positive number from 1 to 10)

[0013]

Embedded image (K is an average value and a positive number from 1 to 10)

[0014]

Embedded image (K is an average value and a positive number from 1 to 10)

[0015]

Embedded image

[0016]

Embedded image

Examples of the phenols (b) which are precursors of the crystalline epoxy resin used in the present invention include, for example, a biphenyl type of the general formula (4), a bisphenol type of the general formula (5), and a phenol of the general formula (6). Stilbene type and the like can be mentioned.

Examples of the biphenyl type phenols of the general formula (4) include 4,4'-dihydroxybiphenyl, 4,4'-dihydroxy-3,3 ', 5,5'-tetramethylbiphenyl, 4,4 '-Dihydroxy-3,
3′-ditert-butyl-6,6′-dimethylbiphenyl, 2,2′-dihydroxy-3,3′-ditert-butyl-6,6′-dimethylbiphenyl, 4,4′-
Dihydroxy-3,3'-ditert-butyl-5,
5'-dimethylbiphenyl, 4,4'-dihydroxy-
3,3 ′, 5,5′-tetratert-butylbiphenyl and the like (including isomers having different substitution positions).
Examples of bisphenol-type phenols of the general formula (5) include bis (4-hydroxyphenyl) methane,
Bis (3-methyl-4-hydroxyphenyl) methane,
Bis (3,5-dimethyl-4-hydroxyphenyl) methane, bis (2,3,5-trimethyl-4-hydroxyphenyl) methane, 1,1-bis (3 ′, 5′-dimethyl-4′-hydroxy Phenyl) ethane, 2,2-bis (4′-hydroxyphenyl) propane, 2,2-bis (3′-methyl-4′-hydroxyphenyl) propane, 2,2-bis (3 ′, 5′-dimethyl) -4'-hydroxyphenyl) propane, 2,2-bis (3'-tert-butyl-4'-hydroxyphenyl) propane,
Bis (2-tert-butyl-5-methyl-4-hydroxyphenyl) sulfide and the like can be mentioned.

The stilbene type phenols of the general formula (6) include, for example, 3-tert-butyl-4,4'-
Dihydroxy-5,3'-dimethylstilbene, 3-tert-butyl-4,4'-dihydroxy-3 ', 6-
Dimethyl stilbene, 3-tert-butyl-2,4 '
-Dihydroxy-3 ', 5', 6-trimethylstilbene, 3-tert-butyl-4,4'-dihydroxy-
3 ′, 5 ′, 6-trimethylstilbene, 3-tert-butyl-4,4′-dihydroxy-3 ′, 5,5′-
Trimethylstilbene, 4,4'-dihydroxy-3,
3'-dimethylstilbene, 4,4'-dihydroxy-
3,3 ′, 5,5′-tetramethylstilbene, 4,
4'-dihydroxy-3,3'-ditertiarybutylstilbene, 4,4'-dihydroxy-3,3'-ditertiarybutyl-6,6'-dimethylstilbene, 2,
2'-dihydroxy-3,3'-ditert-butyl-
6,6′-dimethylstilbene, 2,4′-dihydroxy-3,3′-ditert-butyl-6,6′-dimethylstilbene, 2,2′-dihydroxy-3,3 ′,
5,5′-tetramethylstilbene, 4,4′-dihydroxy-3,3′-ditert-butyl-5,5′-dimethylstilbene, 4,4′-dihydroxy-3,
3 ', 5,5'-tetratert-butylstilbene and the like (including isomers having different substitution positions).

Of these, 4,4'-dihydroxybiphenyl and 4,4'-dihydroxy-3,3 ', 5,5'-tetramethyl are preferred in view of availability, performance, raw material price and the like. Biphenyl, bis (3,5-dimethyl-4-
Hydroxyphenyl) methane, bis (2,3,5-trimethyl-4-hydroxyphenyl) methane, 2,2-bis (3′-methyl-4′-hydroxyphenyl) propane, 2,2-bis (3 ′, 5'-dimethyl-4'-hydroxyphenyl) propane, bis (2-tert-butyl-5-methyl-4-hydroxyphenyl) sulfide (the above seven phenols are hereinafter referred to as group a), 3-
Tert-butyl-2,4'-dihydroxy-3 ',
5 ', 6-trimethylstilbene, 3-tert-butyl-4,4'-dihydroxy-3', 5 ', 6-trimethylstilbene, 3-tert-butyl-4,4'-dihydroxy-3', 5 5′-trimethylstilbene (the above three phenols are hereinafter referred to as group b), 4,
4′-dihydroxy-3,3 ′, 5,5′-tetramethylstilbene, 4,4′-dihydroxy-3,3′-ditert-butyl-6,6′-dimethylstilbene,
2,2′-dihydroxy-3,3′-ditert-butyl-6,6′-dimethylstilbene, 2,4′-dihydroxy-3,3′-di-tert-butyl-6,6′-dimethylstilbene, 2, 2'-dihydroxy-3,
3 ', 5,5'-tetramethylstilbene, or 4,
4'-dihydroxy-3,3'-ditert-butyl-
One or more selected from 5,5'-dimethylstilbene (the above six phenols are hereinafter referred to as group c) are preferred.

Of the group a, biphenyl-type phenols have a high viscosity reducing effect and a high reactivity of 4,4 '.
Those containing a dihydroxybiphenyl skeleton are preferred,
In other group a, bis (3,5-dimethyl-4-hydroxyphenyl) methane, 2,2-bis (3 ′, 5′-)
Dimethyl-4'-hydroxyphenyl) propane and bis (2-tert-butyl-5-methyl-4-hydroxyphenyl) sulfide are preferred. In the case of stilbene-type phenols, a mixture of at least one selected from the group b and at least one selected from the group c is preferable because the softening point is low. The mixing ratio, mixing method, and the like are not particularly limited.

The weight ratio (a / b) of the polyfunctional phenolic resin (a) of the present invention to the phenols (b) as a precursor of the crystalline epoxy resin is preferably from 1 to 19, and in particular,
1.5 to 9 is preferred. If the weight ratio is less than 1, high Tg derived from the polyfunctional epoxy resin formed upon glycidyl etherification and bending strength at the time of heating cannot be sufficiently exhibited, which is not preferable. On the other hand, when the weight ratio is more than 19, the properties such as low viscosity, low modulus of elasticity, high adhesion, and excellent solder crack resistance derived from the crystalline epoxy resin produced when glycidyl etherified cannot be sufficiently exhibited. Absent. The method for synthesizing the epoxy resin (A) of the present invention is not particularly limited. For example, after dissolving a mixed polyhydric phenol in an excess of epichlorohydrin, the presence of an alkali metal hydroxide such as sodium hydroxide, potassium hydroxide, etc. A method in which the reaction is carried out at 50 to 150 ° C, preferably 60 to 120 ° C for 1 to 10 hours, may be mentioned. After completion of the reaction, excess epichlorohydrin is distilled off, and the residue is dissolved in a solvent such as toluene or methyl isobutyl ketone, filtered, washed with water to remove inorganic salts, and then obtained by distilling off the solvent. it can. It is desirable that the generated epoxy resin (A) has as few chlorine ions, sodium ions and other free ions as possible. The softening point of the epoxy resin (A) of the present invention is preferably in the range of 70 to 120C, particularly preferably 80 to 110C. If it is less than 70 ° C., it is liquid or semi-solid at room temperature,
It is not preferable because there is a problem of workability after the glycidyl etherification treatment, a decrease in the room temperature storage stability of the resin composition using the same, or a decrease in Tg and hot bending strength of the cured product. If the temperature exceeds 120 ° C., the viscosity of the polyfunctional epoxy resin itself produced during glycidyl etherification increases, and the effect of lowering the viscosity of the crystalline epoxy resin component produced at the same time becomes undesirably low. The method for measuring the softening point of the epoxy resin (A) is described in JIS K 7234.
According to.

The epoxy resin (A) of the present invention preferably has a heat of fusion of 5 to 35 mJ / mg. This heat of fusion originates from the crystalline epoxy resin generated by glycidyl etherification of the phenols (b) used. If it is less than 5 mJ / mg, the epoxy resin (A) has a low softening point, and the workability is remarkably reduced, which is not preferable. If it exceeds 35 mJ / mg, it exhibits a behavior like a crystalline epoxy resin, and cannot maintain high Tg and curing reactivity derived from the polyfunctional epoxy resin, which is not preferable. The heat of fusion in the present invention indicates the calorific value of the endothermic peak when the temperature is raised from room temperature at a temperature rising rate of 5 ° C./min using a differential scanning calorimeter (manufactured by Seiko Instruments Inc.). Further, other epoxy resins can be used in combination as long as the properties of the epoxy resin (A) of the present invention are not impaired. Examples of the epoxy resin that can be used in combination include a cresol novolak type epoxy resin, a naphthalene type epoxy resin, and a dicyclopentadiene-modified phenol type epoxy resin. These may be used alone or in combination.

The phenolic resin curing agent represented by the general formula (3) used in the present invention is obtained, for example, by polymerizing bis (methoxymethyl) biphenyl and bis (methoxymethyl) benzene with phenols by Friedel-Crafts reaction. can get. The cured product of the resin composition using the phenolic resin curing agent represented by the general formula (3) has a low modulus of elasticity in a high temperature range exceeding Tg, and has a low hygroscopic property. It has features of being able to reduce stress, being excellent in solder crack resistance, and being excellent in adhesion to a substrate after soldering. This resin has improved curability of the resin composition and is excellent in moldability as compared with a phenol aralkyl resin containing only a diphenylene skeleton. Further, as compared with a phenol aralkyl resin containing only a phenylene skeleton, a cured product of the resin composition has characteristics of low hygroscopicity and low elasticity when heated, and is excellent in adhesive strength and solder crack resistance. When a phenol aralkyl resin containing only a diphenylene skeleton and a phenol aralkyl resin containing only a phenylene skeleton are simply mixed, a phenol aralkyl resin containing only a phenylene skeleton having a high curability forms a cured network structure first and has a low curability. Since the phenol aralkyl resin containing only the diphenylene skeleton is left behind during curing, the phenol aralkyl resin containing only the diphenylene skeleton bleeds at the interface between the surface of the molded product and the mold, causing stains on the mold and the surface of the molded product, Since the cured network structure is not uniform, mechanical properties such as bending strength are reduced. On the other hand, the phenolic resin curing agent represented by the general formula (3) having both a diphenylene structure and a phenylene structure in one molecule has the characteristics of both resins in a well-balanced manner, and has a uniform curing behavior and a uniform curing behavior. Form a cured product structure.

R4 and R5 in the general formula (3) each have 1 carbon atom.
5 to 5 alkyl groups, which may be the same or different, d is an integer of 0 to 3, e is an integer of 1 to 4, m and n are average values, and all are 1 to 10 Is a positive number. If any of them exceeds 10, the fluidity is poor, which is not preferable. More preferred m and n are 1 to 5. The ratio of m to the sum of m and n is preferably 0.1 to 0.9. 0.
If it is less than 1, the decrease in elastic modulus at high temperature is small, and 0.9
If it exceeds, the curability tends to be poor. Further, in the general formula (3), a resin having d of 0 and e of 0 is preferable from the balance of curability, fluidity, elastic modulus at high temperature, and the like. Further, other phenol resin curing agents can be used in combination as long as the properties of the phenol resin curing agent of the present invention are not impaired. Examples of the phenol resin curing agent that can be used in combination include, for example, phenol novolak resin, cresol novolak resin, dicyclopentadiene-modified phenol resin, naphthol aralkyl resin, terpene-modified phenol resin, and the like, and these may be used alone or in combination. . Further, from the viewpoint of long-term reliability of the semiconductor device, it is desirable that chlorine ions, sodium ions, and other free ions contained as impurities be as small as possible. The equivalent ratio between the number of epoxy groups of all epoxy resins and the number of phenolic hydroxyl groups of all phenolic resin curing agents is preferably 0.5 to 2.0. If the equivalent ratio is outside this range, the curability of the resin composition is reduced or cured. Things T
It is not preferable because there is a possibility that g may decrease.

The type of the inorganic filler used in the present invention is not particularly limited, and those generally used for a sealing material can be used. For example, fused silica,
Examples thereof include fused spherical silica, crystalline silica, secondary aggregated silica, alumina, titanium white, and aluminum hydroxide. Particularly preferred is fused spherical silica. The shape of the spherical silica is indefinitely spherical for improving fluidity,
Preferably, the particle size distribution is broad. The amount of the inorganic filler is 250 to 250 parts by weight based on 100 parts by weight of the total amount of all epoxy resins and all phenolic resin curing agents.
1400 parts by weight are preferred. If it is less than 250 parts by weight, low thermal expansion and low moisture absorption cannot be obtained, and solder crack resistance is insufficient. If it exceeds 1400 parts by weight, fluidity is reduced, and poor filling or the like occurs during molding, It is not preferable because inconvenience such as gold wire deformation in the semiconductor device due to the increase in viscosity may occur. It is preferable that these inorganic fillers are sufficiently mixed in advance. Further, if necessary, the inorganic filler may be treated with a coupling agent or an epoxy resin or a phenol resin curing agent in advance, and may be used. As a treatment method, a method of removing the solvent after mixing using a solvent or For example, there is a method of directly adding to an inorganic filler and treating it using a mixer.

The curing accelerator used in the present invention may be any as long as it promotes the crosslinking reaction between the epoxy resin and the phenol resin curing agent. For example, 1,8-diazabicyclo (5,4,0) undecene-7 Amidine compounds such as
Organophosphorus compounds such as triphenylphosphine, tetraphenylphosphonium and tetraphenylborate salts,
Examples include imidazole compounds such as 2-methylimidazole, but are not limited thereto. These curing accelerators may be used alone or as a mixture.

The epoxy resin composition of the present invention comprises (A)
In addition to component (D), if necessary, brominated epoxy resin, antimony oxide, flame retardant such as phosphorus compound, inorganic ion exchanger such as bismuth oxide hydrate, cup such as γ-glycidoxypropyltrimethoxysilane Ring agents, coloring agents such as carbon black and red iron, low-stress components such as silicone oil and silicone rubber, release agents such as natural wax, synthetic wax, higher fatty acids and their metal salts or paraffin, various antioxidants, etc. Additives may be appropriately compounded. The epoxy resin composition of the present invention comprises (A)
-Component (D), other additives, etc. are mixed at room temperature using a mixer, melt-kneaded with a kneader such as a roll, kneader, extruder, etc., cooled and pulverized. In order to manufacture a semiconductor device by encapsulating an electronic component such as a semiconductor element using the epoxy resin composition of the present invention, it is sufficient to cure and mold by a molding method such as a transfer mold, a compression mold, and an injection mold.

[0029]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the present invention. The mixing ratio is by weight. The polyfunctional phenolic resins used in the synthesis of the epoxy resins A to E used in the examples and comparative examples were obtained by using the above formulas (7) and (1).
0). As phenols which are precursors of the crystalline epoxy resin, 4,4′-dihydroxy-3,3 ′,
5,5′-tetramethylbiphenyl, 3-tert-butyl-4,4′-dihydroxy-3 ′, 5 ′, 6-trimethylstilbene, 4,4′-dihydroxy-3,
3 ', 5,5'-tetramethylstilbene was used. The synthesized epoxy resins A to E were obtained by glycidyl etherification according to a conventional method using the formulations shown in Table 1. The mixing ratio is by weight. The characteristics are shown in Table 1. The softening point and heat of fusion were measured by the methods described above.

[Table 1]

Example 1 Epoxy resin A 41.6 parts by weight Phenolic resin curing agent of formula (12) (m is 3.2, n is 1.2. Hydroxyl equivalent 196 g / eq) 58.4 parts by weight Melted sphere Silica (average particle size: 15 μm) 910.5 parts by weight 1,8-diazabicyclo (5,4,0) undecene-7 (hereinafter referred to as DBU) 4.2 parts by weight Brominated phenol novolak type epoxy resin (epoxy equivalent: 275 g / eq) 10.5 parts by weight Antimony trioxide 10.5 parts by weight Carbon black 3.2 parts by weight Carnauba wax 5.3 parts by weight Other additives 8.5 parts by weight were mixed at room temperature using a mixer, The mixture was kneaded at 120 ° C. using a biaxial roll, cooled and pulverized to obtain a resin composition. The obtained resin composition was evaluated by the following method.
Table 2 shows the results.

Embedded image

Spiral flow: EMMI-1-66
The measurement was performed at a mold temperature of 175 ° C., an injection pressure of 70 kg / cm ² , and a curing time of 2 minutes using a mold for spiral flow measurement according to the above. The unit is cm. Curing torque: Using a curast meter (manufactured by Orientec Co., Ltd., JSR curast meter IVPS type)
The torque was determined at a mold temperature of 175 ° C. and 90 seconds after the start of heating. The torque in the curast meter is a parameter of curability, and the larger the numerical value, the better the curability. The unit is kgf · cm. -Moisture absorption: mold temperature 1 using a transfer molding machine
A molded product having a diameter of 50 mm and a thickness of 3 mm was formed at 75 ° C., an injection pressure of 75 kg / cm ² , and a curing time of 2 minutes, and was treated as a post cure at 175 ° C. for 8 hours. It was left for 696 hours in an environment with a humidity of 60%, and the change in weight was measured to determine the moisture absorption. The unit is% by weight. -Hot strength, hot elastic modulus: The hot flexural strength and the hot flexural modulus were measured (at 240 ° C) according to JIS K 6911. The unit is N / mm ² .・ Package warpage: Using a transfer molding machine
225 pBGA with a mold temperature of 175 ° C., an injection pressure of 75 kg / cm ² and a curing time of 2 minutes (substrate is 0.36 mm thick, bismaleimide / triazine resin / glass cloth substrate, package size is 24 × 24 mm, thickness is 1.17 mm) ,
Silicon chip is 9 × 9mm in size and 0.35m in thickness
m, 25 μm between the chip and the bonding pad of the circuit board
It is bonded with a gold wire of m diameter. ) Was molded. Further, post-curing was performed at 175 ° C. for 8 hours. After cooling to room temperature, the displacement in the height direction was measured diagonally from the gate of the package using a surface roughness meter, and the largest value of the displacement difference was defined as the amount of warpage. The unit is μm.

Substrate adhesion: using a transfer molding machine, mold temperature 175 ° C., injection pressure 75 kg / cm ² ,
A molded article was molded with a curing time of 2 minutes. This molded product was post-cured at 175 ° C. for 8 hours, and then the molded product portion and the base material portion were sandwiched by a jig using a tensile tester, and the molded product portion was fixed. The portion was pulled upward to measure the substrate adhesion. The target substrate is a 42 alloy frame and a polymethyl methacrylate solder resist (PMMA) applied to the surface of the 42 alloy frame. The unit is N / mm ² . -Solder crack resistance: Using a transfer molding machine
225 pBGA with a mold temperature of 175 ° C., an injection pressure of 75 kg / cm ² and a curing time of 2 minutes (substrate is 0.36 mm thick, bismaleimide / triazine resin / glass cloth substrate, package size is 24 × 24 mm, thickness is 1.17 mm) ,
Silicon chip is 9 × 9mm in size and 0.35m in thickness
m, 25 μm between the chip and the bonding pad of the circuit board
It is bonded with a gold wire of m diameter. ) Was molded. Eight packages treated at 175 ° C. for 8 hours as post cure were treated at 30 ° C. and a relative humidity of 60% for 696 hours, and then subjected to IR reflow treatment (240 ° C.). After the treatment, the presence of peeling and cracks in the inside was observed with an ultrasonic flaw detector, and the number of defective packages was counted. When the number of defective packages is n, it is displayed as n / 8.

Examples 2 and 3 and Comparative Examples 1 to 5 Resin compositions were obtained in the same manner as in Example 1 according to the formulations in Tables 2 and 3, and evaluated in the same manner as in Example 1. The results are shown in Tables 2 and 3. In Comparative Examples 1 and 5, a phenol novolak resin curing agent (hydroxyl equivalent: 104 g / eq) was used.
In Comparative Examples 4 and 5, the epoxy resin of the formula (13) (epoxy equivalent: 154 g / eq) was used. In Comparative Example 4, 4,4 ′
-Bis (2,3-epoxypropoxy) -3,3 ',
An epoxy resin containing 5,5′-tetramethylbiphenyl as a main component (epoxy equivalent: 197 g / eq; hereinafter, referred to as epoxy resin (E-1)) was used.

[0034]

Embedded image

[0035]

[Table 2]

[0036]

[Table 3]

[0037]

According to the present invention, an epoxy resin composition having excellent moldability can be obtained, and an area-mounted semiconductor device using the same has a small warpage during soldering, a low elastic modulus, a high adhesion, and an excellent resistance. Excellent solder cracking properties.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01L 23/29 H01L 23/30 R 23/31 F-term (Reference) 4J002 CC27X CD04W CD05W FD016 FD14X FD157 GQ05 4J036 AA02 AC02 AC03 AD04 AD07 AD08 AD10 AD15 AD20 DA04 DA05 FA01 FB08 JA07 4M109 AA01 BA03 BA05 CA21 CA22 EA04 EA06 EB03 EB04 EB06 EB07 EB08 EB09 EB12 EB13 EB19 EC03 EC04 EC20

Claims (4)

[Claims] (A) A polyfunctional phenol resin (a) represented by the general formula (1) and / or the general formula (2) is mixed with a phenol (b) which is a precursor of a crystalline epoxy resin. Glycidyl etherified epoxy resin, (B)
A phenolic resin curing agent represented by the general formula (3), (C)
Inorganic filler, and (D) curing accelerator as essential components,
The weight ratio (a / b) between (a) and (b) is 1 to 19, the softening point of the epoxy resin (A) is 70 to 120 ° C., and the total phenol resin curing agent with respect to the epoxy group of all epoxy resins. The equivalent ratio of the phenolic hydroxyl groups of the epoxy resin is 0.5 to 2.0, and the content of the inorganic filler is 250 to 1 per 100 parts by weight of the total amount of all epoxy resins and all phenolic resin curing agents.
An epoxy resin composition for semiconductor encapsulation, which is 400 parts by weight. Embedded image (R1 and R2 are alkyl groups having 1 to 5 carbon atoms, which may be the same or different from each other; a = 0 to 0)
Integer of 3, integer of b = 0 to 4, k is an average value of 1 to 10
The positive number of (R3 is an alkyl group having 1 to 5 carbon atoms, which may be the same as or different from each other; c = an integer of 0 to 4) (R4 and R5 are alkyl groups having 1 to 5 carbon atoms, which may be the same or different. D = 0 to 0
An integer of 3, an integer of e = 1 to 4, m and n are average values, and all are positive numbers of 1 to 10) 2. A phenol resin (a) represented by the general formula (1) and / or (2) and a phenol (b) which is a precursor of a crystalline epoxy resin are mixed and glycidyl etherified. The epoxy resin composition for semiconductor encapsulation according to claim 1, wherein the epoxy resin (A) has a heat of fusion of 5 to 35 mJ / mg. 3. The phenol (b) which is a precursor of the crystalline epoxy resin is at least one selected from the general formula (4), the general formula (5), and the general formula (6). Or the epoxy resin composition for semiconductor encapsulation according to 2. Embedded image (R6 is an alkyl group having 1 to 5 carbon atoms, which may be the same or different from each other; f = an integer of 0 to 4) Embedded image (R9 is an atom or group selected from hydrogen and an alkyl group having 1 to 5 carbon atoms, which may be the same or different from each other. R10 is an alkyl group having 1 to 5 carbon atoms. Group, h = an integer of 0 to 4, which may be the same or different from each other) 4. A semiconductor device comprising a semiconductor element encapsulated with the epoxy resin composition for semiconductor encapsulation according to claim 1, 2 or 3.