JP2003048959A - Epoxy resin composition and semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an epoxy resin composition for semiconductor sealing having characteristics excellent in resistance to crack caused by soldering, flame retardance and high-temperature storage property. SOLUTION: This epoxy resin composition comprises (A) an epoxy resin, (B) a phenol resin, (C) a curing accelerator, (D) an inorganic filler and (E) an organopolysiloxane represented by the general formula (wherein Rs are each a monovalent organic group in which 30-100 wt.% of total organic groups are phenyl groups and the residual organic groups are one or more groups selected from a group consisting of a vinyl group-substituted organic group, a 1-6C alkylalkoxy group, a 1-6C alkyl group, an amino group-substituted organic group, an epoxy group-substituted organic group, a hydroxy group- substituted organic group and a mercapto group-substituted organic group; n is a positive number of average 5-100).

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 and a semiconductor device which have excellent adhesiveness and solder crack resistance.

[0002]

2. Description of the Related Art Conventionally, electronic parts such as diodes, transistors and integrated circuits are mainly sealed with an epoxy resin composition. These epoxy resin compositions are required to have excellent fluidity, solder crack resistance and flame retardancy at the same time. In order to improve fluidity and solder crack resistance, use of a biphenyl type epoxy resin or a phenol aralkyl resin (Japanese Patent Laid-Open No. 11-1541) has been proposed, but in recent years, there has been a demand for a solder containing no lead. On the other hand, because the melting temperature of the solder containing no lead is high, the temperature required for soldering is increased from the conventional 240 ° C. to 260 ° C., and solder cracks are more likely to occur, so that more solder resistant It is necessary to improve crackability.

Conventionally, epoxy resin compositions for semiconductor encapsulation have usually been blended with halogen-based flame retardants and antimony compounds in order to impart flame retardancy. However, due to environmental concerns, halogen-based flame retardants and antimony compounds have been incorporated. There is a demand for the development of an epoxy resin composition which is excellent in flame retardancy even without using. As a countermeasure against this, a method of using a phosphoric acid ester additive and a resin containing a nitrogen element in combination (Japanese Patent Laid-Open No. 11-189704) has been proposed, but the flame retardancy is still insufficient and the amount of the flame retardant added is There is a need to develop an epoxy resin composition that can be minimized. Further, when the semiconductor device is stored at a high temperature for a long time, there is a phenomenon that voids and cracks occur in the eutectic part of the gold wire and the aluminum pad. This phenomenon is called high temperature storage characteristics. When the epoxy resin composition for semiconductor encapsulation contains brominated flame retardants and antimony compounds derived from flame retardants, these bromine and antimony corrode the eutectic part of gold / aluminum, resulting in high temperature storage characteristics. Has the effect of significantly reducing Therefore, there is a demand for an epoxy resin composition that can minimize the amount of the brominated flame retardant or antimony compound added.

[0004]

DISCLOSURE OF THE INVENTION The present invention provides an epoxy resin composition and a semiconductor device having excellent adhesiveness, good solder crack resistance, high temperature storage characteristics and excellent flame resistance. is there.

[0005]

The present invention provides [1] (A)
Epoxy resin for semiconductor encapsulation, comprising an epoxy resin, (B) phenol resin, (C) curing accelerator, (D) inorganic filler and (E) organopolysiloxane represented by the general formula (1). Composition,

[0006]

[Chemical 7] (R is a monovalent organic group, and is 30 to 100 of all organic groups.
% By weight is a phenyl group, the remaining organic groups are vinyl group-substituted organic groups, C1-6 alkylalkoxy groups, C1
To 6 alkyl groups, amino group-substituted organic groups, epoxy group-substituted organic groups, hydroxyl group-substituted organic groups, and mercapto group-substituted organic groups. n is the average value,
5-100 positive number)

[2] The residual organic group of the organopolysiloxane represented by the general formula (1) is one or more selected from the group consisting of a vinyl group-substituted organic group and an alkylalkoxy group having 1 to 6 carbon atoms. The epoxy resin composition for semiconductor encapsulation according to the item [1], wherein the amount thereof is 50% by weight or less of all the organic groups, and the epoxy resin [3] has the formula (2), the formula (3), or The first [1] term or the second [2] represented by the equation (4)
The epoxy resin composition for semiconductor encapsulation according to the item,

[0008]

[Chemical 8]

[0009]

[Chemical 9] (N is an average value and is a positive number from 1 to 10)

[0010]

[Chemical 10] (N is an average value and is a positive number from 1 to 10)

[4] The epoxy resin composition for semiconductor encapsulation according to [1] to [3], wherein the phenol resin is represented by the formula (5) or (6).

[0012]

[Chemical 11] (N is an average value and is a positive number from 1 to 10)

[0013]

[Chemical 12] (N is an average value and is a positive number from 1 to 10)

[5] A semiconductor device comprising a semiconductor element encapsulated with the epoxy resin composition for semiconductor encapsulation according to any one of items [1] to [4]. is there.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION The epoxy resin used in the present invention refers to all monomers, oligomers and polymers having two or more epoxy groups in one molecule, and its molecular weight and molecular structure are not particularly limited. For example, biphenyl type epoxy resin, bisphenol type epoxy resin, stilbene type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, triphenol methane type epoxy resin, alkyl modified triphenol methane type epoxy resin, triazine nucleus-containing epoxy resin, Examples thereof include a dicyclopentadiene-modified phenol type epoxy resin, a phenol aralkyl type epoxy resin (having a phenylene skeleton and a diphenylene skeleton), a naphthol type epoxy resin, and the like, and these may be used alone or in combination. From the viewpoint of improving the solder crack resistance, the epoxy resins represented by the formulas (2), (3) and (4), and the formula (3) from the viewpoint of flame retardancy are particularly preferably used.

As the phenol resin used in the present invention,
Monomers, oligomers, and polymers having two or more phenolic hydroxyl groups in one molecule are generally mentioned, and their molecular weight and molecular structure are not particularly limited. For example, phenol novolac resin, cresol novolac resin, dicyclopentadiene-modified phenol resin , Terpene-modified phenol resin, triphenol methane type resin, phenol aralkyl resin (having a phenylene skeleton, diphenylene skeleton, etc.), naphthol aralkyl resin, and the like,
You may use individually or in mixture. From the viewpoint of improving solder crack resistance, the phenol resins represented by the formulas (5) and (6) are preferably used, and from the viewpoint of flame retardancy, the formula (6) is particularly preferably used. As a blending amount of these, the ratio of the number of epoxy groups of all epoxy resins to the number of phenolic hydroxyl groups of all phenol resins is preferably 0.8 to 1.3.

The curing accelerator used in the present invention may be any one as long as it accelerates the curing reaction between the epoxy group and the phenolic hydroxyl group, and those generally used for sealing materials can be used. Examples include 1,8-diazabicyclo (5,4,0) undecene-7, triphenylphosphine, 2-methylimidazole, tetraphenylphosphonium tetraphenylborate, and triphenylphosphine adducted with benzoquinone. However, they may be mixed and used.

As the inorganic filler used in the present invention, those generally used for sealing materials can be used. Examples thereof include fused silica, crystalline silica, talc, alumina, silicon nitride, and the like, and these may be used alone or in combination. The amount of the inorganic filler compounded is preferably 60 to 95% by weight in the total epoxy resin composition from the viewpoint of balance between moldability and solder crack resistance. 60
If it is less than 95% by weight, the solder crack resistance is lowered due to an increase in moisture absorption rate, and if it exceeds 95% by weight, there may occur problems in formability such as wire sweep and pad shift.

The organopolysiloxane represented by the general formula (1) used in the present invention improves the adhesion to various metals in the semiconductor device, and as a result, improves the solder crack resistance especially at 260 ° C. Furthermore, it is possible to improve flame retardancy and high temperature storage characteristics. R in the organopolysiloxane represented by the general formula (1) is a monovalent organic group, 30 to 100% by weight of all organic groups are phenyl groups, and the remaining organic groups are vinyl group-substituted organic groups, Carbon number 1
6 alkylalkoxy groups, C1-6 alkyl groups, amino group-substituted organic groups, epoxy group-substituted organic groups, hydroxyl group-substituted organic groups, mercapto group-substituted organic group consisting of one or more groups, This organopolysiloxane is a low molecular weight liquid compound.

Since the siloxane skeleton has a phenyl group, a vinyl group-substituted organic group, and an alkylalkoxy group having 1 to 6 carbon atoms, it can be easily dissolved in the resin component and plasticized, so that the epoxy resin composition can be used for various metals. It facilitates adhesion and can improve adhesion. Further, 30 to 100% by weight of all the organic groups are phenyl groups, and the phenyl groups contribute to the improvement of flame retardancy. Further, since the organopolysiloxane used in the present invention is stable at high temperature, it is hardly decomposed by heat, hardly generates corrosive gas, does not deteriorate the gold / aluminum eutectic portion, and improves high temperature storage characteristics. In the case of polydimethylsiloxane, which has been conventionally used in epoxy resin compositions for semiconductor encapsulation, a polyalkylene oxide component is introduced in order to make it compatible with the resin component, but since this polyalkylene oxide component is a hydrophilic group, it is water resistant. Inferior in performance, the semiconductor device sealed with the epoxy resin composition containing the organopolysiloxane tends to have a higher water absorption rate and a lower solder crack resistance. However, since the organopolysiloxane represented by the general formula (1) of the present invention does not contain polyalkylene oxide, the problem of high water absorption does not occur.

R in the organopolysiloxane represented by the general formula (1) is a monovalent organic group, and 3 out of all the organic groups.
It is essential that 0 to 100% by weight is a phenyl group. If it is less than 30% by weight, the compatibility with the resin component, the contribution to the improvement of flame retardancy, and the high temperature storage property may be deteriorated. The degree of polymerization of the organopolysiloxane in the present invention (the value of n in the general formula (1)) is preferably 5 to 100. If the average value n is less than 5, the vapor pressure at a high temperature becomes high, and the epoxy resin composition evaporates at the molding temperature and does not remain in the semiconductor device. If n exceeds 100, the epoxy resin composition melts. This is not preferable because the viscosity increases and the moldability decreases.

The remaining organic groups other than the phenyl group are preferably one or more groups selected from a vinyl group-substituted organic group and an alkylalkoxy group having 1 to 6 carbon atoms. 50% by weight or less of the group is desirable. When it exceeds 50% by weight, the flame retardancy may be reduced because the content of the phenyl group is reduced. From the viewpoint of improving flame retardancy, a vinyl group-substituted organic group that promotes a radical reaction during combustion and an alkylalkoxy group having 1 to 6 carbon atoms that chemically reacts with silica during combustion are desirable.

The epoxy resin composition of the present invention comprises (A)-
In addition to the component (E), if necessary, a brominated epoxy resin, antimony trioxide, red phosphorus, an organic phosphorus compound, a flame retardant such as a metal hydroxide may be contained. For applications requiring stability of electrical properties at a high temperature of ℃, the content of bromine atom and antimony atom is preferably less than 0.1% by weight in the total epoxy resin composition, and More preferably, it is not included. Either bromine atom or antimony atom is 0.1
If the content is more than 5% by weight, the resistance value of the semiconductor device increases with time when left at a high temperature, and finally there is a possibility that the gold wire of the semiconductor element may be broken. Also, from the viewpoint of environmental protection, it is desirable that the content of each of bromine atom and antimony atom is less than 0.1% by weight, and the content thereof is as small as possible.

The epoxy resin composition of the present invention comprises (A)-
Ingredient (E) is an essential component, but if necessary, a silane coupling agent, a coloring agent such as carbon black, a release agent such as natural wax or synthetic wax, and a low stress such as silicone oil or rubber. Various additives such as additives may be appropriately blended. The epoxy resin composition of the present invention is prepared by thoroughly and uniformly mixing the components (A) to (E) and other additives with a mixer or the like, and then melt-kneading them with a hot roll or a kneader and cooling them. Obtained by crushing. By using the epoxy resin composition of the present invention, various electronic components such as semiconductor elements are sealed and semiconductor devices are manufactured by curing molding by a conventional molding method such as transfer molding, compression molding or injection molding. do it.

[0025]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited thereto. The mixing ratio is parts by weight. <Example 1> 5.8 parts by weight of biphenyl type epoxy resin (melting point 105 ° C, epoxy equivalent 191: manufactured by Japan Epoxy Resin Co., Ltd. YX-4000HK) (hereinafter (E-1)).

[0026]

[Chemical 13]

[0027]   Phenol aralkyl resin (softening point 80 ° C), hydroxyl equivalent 174: Mitsui Chemicals ( Co., Ltd. XLC-LL) (hereinafter, (H-1)) 5.2 parts by weight

[0028]

[Chemical 14]

1,8-diazabicyclo (5,4,0) undecene-7 (hereinafter DBU) 0.2 part by weight fused spherical silica (average particle size 20 μm) 87.0 parts by weight Organopolysiloxane (see Table 1 1.0 parts by weight carbon black 0.3 parts by weight epoxy silane coupling agent 0.2 parts by weight carnauba wax 0.5 parts by weight at room temperature after mixing with a mixer at room temperature.
The mixture was kneaded using two rolls at 45 ° C and 45 ° C, cooled, and then pulverized to obtain an epoxy resin composition. The obtained epoxy resin composition was evaluated by the following methods. The results are shown in Table 2.

<Evaluation method> Spiral flow: A spiral flow measurement mold conforming to EMMI-1-66 was used at a mold temperature of 175 ° C., an injection pressure of 6.9 MPa, and a curing time of 120 seconds. The unit is cm. Moisture absorption rate: Mold temperature 1 using low pressure transfer molding machine
A disk (diameter 50 mm, thickness 4 mm) was molded at 75 ° C., an injection pressure of 3.7 MPa, and a curing time of 120 seconds.
After post-curing for 8 hours, a drying treatment was performed at 150 ° C. for 16 hours, and a treatment performed at 85 ° C. and 85% relative humidity for 168 hours was performed. The unit is% by weight. Flame resistance: Mold temperature 1 using low pressure transfer molding machine
A test piece (127 mm × 12.7 mm × 3.2 mm) was molded at 75 ° C., an injection pressure of 11.0 MPa, and a curing time of 120 seconds, post-cured at 175 ° C. for 8 hours, and then according to the UL-94 vertical method. The flame retardancy was determined by measuring ΣF and Fmax. Solder crack resistance: Mold temperature 175 ° C., injection pressure 9.6 MPa, curing time 1 using low pressure transfer molding machine
80pQFP (2mm thickness, chip size 9.0 in 20 seconds)
mm × 9.0 mm), and post-cured at 175 ° C. for 8 hours, and leave the resulting package at 85 ° C. and 85% relative humidity for 168 hours. Soaked for 2 seconds. The packages were observed with a microscope, and the crack generation rate [(crack generation rate) = (number of external crack generation packages) / (total number of packages) × 100] was calculated. Units%. Further, the ratio of the peeling area of the semiconductor element and the cured product of the epoxy resin composition was measured using an ultrasonic flaw detector, and the peeling rate [(peeling rate) = (peeling area) / (semiconductor element area) × 100] was calculated. I asked. Units%. High temperature storage characteristics: Mold temperature 175 ° C., injection pressure 9.6 MPa, curing time 120 using low pressure transfer molding machine
16 pDIP in seconds (chip size 3.0 mm x 3.5 m
m) is molded and post-cured at 175 ° C. for 8 hours, and then a high temperature storage test (200 ° C., 500 hours) is performed. did. The defective rate in 15 packages is shown in percentage. Units%.

<Examples 2 to 5 and Comparative Examples 1 to 3> According to the formulations shown in Table 1, epoxy resin compositions were obtained in the same manner as in Example 1 and evaluated in the same manner as in Example 1. The results are shown in Table 2.
Shown in. The structural formulas of the resins used other than in Example 1 are shown below. Brominated bisphenol A used in Examples 3 and 5
The epoxy equivalent of the type epoxy resin is 365. Properties other than the organopolysiloxane are shown in Table 1. The organopolysiloxane is obtained by substituting part of the methyl groups of polydimethylsiloxane with polyethylene oxide, and the polyethylene oxide content (% by weight) represents (polyethylene oxide component) / (total methyl groups). n is 44.

[0032]

[Chemical 15]

[0033]

[Table 1]

[0034]

[Table 2]

[0035]

EFFECT OF THE INVENTION The epoxy resin composition of the present invention has low water absorption, improves adhesion to various metals, is particularly excellent in solder crack resistance at 260 ° C., and is excellent in flame retardancy and high temperature storage characteristics. It is possible to obtain a good semiconductor device.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H01L 23/31 F term (reference) 4J002 CC07X CD02W CD04W CD07W DE147 DJ007 DJ017 DJ047 EU096 EU116 EW136 FD017 FD156 GQ05 4J036 AD07 AE05 AE07 AF08 DB05 DC38 DC41 DD07 FA05 FA06 FB08 JA07 4M109 AA01 BA01 CA21 EA02 EB03 EB04 EB12 EB18 EC05 EC09 EC20

Claims (5)

[Claims] 1. A composition comprising (A) an epoxy resin, (B) a phenol resin, (C) a curing accelerator, (D) an inorganic filler and (E) an organopolysiloxane represented by the general formula (1). The epoxy resin composition for semiconductor encapsulation. [Chemical 1] (R is a monovalent organic group, and is 30 to 100 of all organic groups.
% By weight is a phenyl group, the remaining organic groups are vinyl group-substituted organic groups, C1-6 alkylalkoxy groups, C1
To 6 alkyl groups, amino group-substituted organic groups, epoxy group-substituted organic groups, hydroxyl group-substituted organic groups, and mercapto group-substituted organic groups. n is the average value,
5-100 positive number) 2. The residual organic group of the organopolysiloxane represented by the general formula (1) is at least one selected from the group consisting of a vinyl group-substituted organic group and an alkylalkoxy group having 1 to 6 carbon atoms. The epoxy resin composition for semiconductor encapsulation according to claim 1, wherein the amount is 50% by weight or less of the total organic groups. 3. The epoxy resin composition for semiconductor encapsulation according to claim 1, wherein the epoxy resin is represented by formula (2), formula (3) or formula (4). [Chemical 2] [Chemical 3] (N is an average value and is a positive number of 1 to 10) (N is an average value and is a positive number from 1 to 10) 4. The phenolic resin is represented by the formula (5) or the formula (6).
The epoxy resin composition for semiconductor encapsulation according to any one of claims 1 to 3. [Chemical 5] (N is an average value and is a positive number of 1 to 10) (N is an average value and is a positive number from 1 to 10) 5. A semiconductor device comprising a semiconductor element encapsulated with the epoxy resin composition for semiconductor encapsulation according to claim 1.