JP2005314565A - Epoxy resin composition and semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an epoxy resin composition for semiconductor sealing that has excellent solder heat resistance and high productivity and provide semiconductor devices. <P>SOLUTION: The epoxy resin composition for semiconductor sealing includes as essential components, epoxy resin, phenol resin, carboxy group-bearing organopolysiloxane and oxidized polyethylene. In a preferred embodiment, the weight ratio of the carboxy group-bearing organopolysiloxane to the oxidized polyethylene is 5/1 to 1/5 in this epoxy resin composition. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an epoxy resin composition for semiconductor encapsulation and a semiconductor device.

  In recent years, in the market trends of downsizing, weight reduction, and high performance of electronic devices, higher integration of semiconductors has progressed year by year, and surface mounting of semiconductor packages has been promoted. In addition, corporate activities in consideration of the global environment are regarded as important, and the waste electronic and electrical equipment (WEEE) by the EU (European Union) has been shown to completely eliminate lead, which is a hazardous substance, except for specific uses by 2006. The melting point of lead-free solder is higher than that of conventional lead / tin solder, and the temperature at the time of solder mounting such as infrared reflow and solder dipping is increased from 220 to 240 ° C. to 240 to 260 ° C. in the future. Due to such an increase in mounting temperature, there is a problem that the resin part is cracked during mounting and reliability cannot be guaranteed. Furthermore, with regard to lead frames, from the viewpoint of lead removal, the use of lead frames pre-plated with nickel / palladium instead of external solder plating is being promoted. Nickel / palladium plating has low adhesion to the sealing material, and peeling occurs at the interface during mounting, and cracks are likely to occur in the resin part.

For such a problem, by applying a low water-absorbing epoxy resin or a curing agent to improve solder heat resistance (for example, see Patent Documents 1, 2, and 3), the mounting temperature rises. The correspondence has come to come. On the other hand, the epoxy resin composition exhibiting such low water absorption and low elastic modulus has a low crosslink density, and the molded product immediately after curing is soft. There was a problem of lowering productivity.
Furthermore, as an effort to improve productivity, a method of adding oxidized polyethylene (for example, see Patent Documents 4 and 5) has been proposed, but sufficient release properties cannot be obtained with oxidized polyethylene alone. In order to obtain releasability, it is necessary to increase the compounding amount, and in this case, the adhesiveness is lowered. In addition, a method using an epoxy polyether silicone having dimethylsiloxane as a main chain for the purpose of improving the dispersion of polyethylene oxide has been proposed (see, for example, Patent Document 6). Although very good in terms of production, there was a problem that the polyether chain increased hygroscopicity and lowered solder heat resistance. Thus, there is a demand for an epoxy resin composition for semiconductor encapsulation that is excellent in solder heat resistance and responds to production problems such as releasability, continuous moldability, appearance of molded products, mold contamination, and the like.

JP-A-9-3161 (pages 2 to 5) JP-A-9-235353 (pages 2-7) Japanese Patent Laid-Open No. 11-140277 (pages 2 to 11) JP-A-8-258077 (pages 2-9) JP 11-152393 A (pages 2 to 5) JP-A-5-315472 (pages 2-7)

  The present invention has been made in order to solve the above-described problems, and an object of the present invention is to provide an epoxy resin composition for semiconductor encapsulation and a semiconductor device having good solder heat resistance and excellent productivity. It is to provide.

The present invention
[1] An epoxy resin composition for semiconductor encapsulation, comprising (A) an epoxy resin, (B) a phenol resin, (C) an organopolysiloxane having a carboxyl group and (D) polyethylene oxide as essential components,
[2] The epoxy resin composition for semiconductor encapsulation according to item [1], wherein the organopolysiloxane having a carboxyl group (C) is an organopolysiloxane represented by the general formula (1);

（式中、Ｒは少なくとも１つ以上がカルボキシル基を有する炭素数１〜４０の一価の有機基であり、残余の基は水素、フェニル基、又はメチル基から選ばれる一価の基であり、互いに同一であっても異なっていてもよい。ｎは平均値で、１〜５０の正数である。）

(In the formula, R is a monovalent organic group having 1 to 40 carbon atoms, at least one of which has a carboxyl group, and the remaining group is a monovalent group selected from hydrogen, phenyl group, or methyl group. And may be the same or different from each other, n is an average value and is a positive number from 1 to 50.)

[3] The epoxy resin composition for semiconductor encapsulation according to [1] or [2], wherein (D) the oxidized polyethylene is obtained by oxidizing high-density polyethylene,
[4] The [D], [2] or [3], wherein the (D) oxidized polyethylene has a maximum particle size of 150 μm or less and an average particle size of 0.1 to 100 μm. Epoxy resin composition for semiconductor encapsulation,
[5] The epoxy resin composition for semiconductor encapsulation according to any one of [1] to [4], wherein the dropping point of (D) the oxidized polyethylene is 100 to 130 ° C.,
[6] Any one of [1] to [5], wherein (C) the organopolysiloxane having a carboxyl group includes an organopolysiloxane having a carboxyl group that has been reacted in advance with an epoxy resin and a curing accelerator. Epoxy resin composition for semiconductor encapsulation,
[7] The [1] to [6], wherein the weight ratio (C) / (D) of the (C) carboxyl group-containing organopolysiloxane and the (D) polyethylene oxide is 5/1 to 1/5. The epoxy resin composition for semiconductor encapsulation according to any one of the items,
[8] The epoxy resin composition for semiconductor encapsulation according to any one of [1] to [7], wherein the (A) epoxy resin is an epoxy resin represented by the general formula (2),

（式中、ｎは平均値で、１〜１０の正数）

(Where n is an average value and a positive number of 1 to 10)

[9] The epoxy resin composition for semiconductor encapsulation according to any one of [1] to [8], wherein the (B) phenol resin is a phenol resin represented by the general formula (3),

（式中、ｎは平均値で、１〜１０の正数）

(Where n is an average value and a positive number of 1 to 10)

[10] A semiconductor device comprising a semiconductor element sealed using the epoxy resin composition for semiconductor sealing according to any one of [1] to [9],
It is.

  According to the present invention, it exhibits excellent solder heat resistance when mounted on a semiconductor device, and problems such as releasability, continuous formability, appearance of molded product, mold contamination, etc., which are conventional defects at the time of sealing molding of semiconductor elements. It is possible to obtain an epoxy resin composition for semiconductor encapsulation that can solve the above.

In the present invention, by incorporating an organopolysiloxane having a carboxyl group and polyethylene oxide as essential components, mold release, continuous moldability, molded product appearance are good, and mold fouling occurs when semiconductor elements are encapsulated. Thus, an epoxy resin composition for semiconductor encapsulation having excellent productivity that is difficult to perform and excellent in solder heat resistance when mounted on a semiconductor device can be obtained.
Hereinafter, the present invention will be described in detail.

（式中、ｎは平均値で、１〜１０の正数） The epoxy resin used in the present invention includes monomers, oligomers, and polymers in general 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, triphenolmethane type epoxy resin, alkyl-modified triphenolmethane type epoxy resin, triazine nucleus-containing epoxy resin, dicyclopentadiene modified phenol type epoxy Examples thereof include resins, phenol aralkyl type epoxy resins (having a phenylene skeleton, a biphenylene skeleton, etc.), naphthol type epoxy resins, and the like. These may be used alone or in combination. From the viewpoint of improving solder crack resistance, an epoxy resin represented by the general formula (2) is preferable.

(Where n is an average value and a positive number of 1 to 10)

（式中、ｎは平均値で、１〜１０の正数） The phenol resin used in the present invention includes monomers, oligomers, and polymers in general having two or more phenolic hydroxyl groups in one molecule, and the molecular weight and molecular structure thereof are not particularly limited. For example, phenol novolak resin, cresol Examples include novolak resin, dicyclopentadiene-modified phenol resin, terpene-modified phenol resin, triphenolmethane type resin, phenol aralkyl resin (having a phenylene skeleton, biphenylene skeleton, etc.), naphthol aralkyl resin, and the like. It may be used. From the viewpoint of improving solder crack resistance, a phenol resin represented by the general formula (3) is preferable. Moreover, as a compounding quantity of a phenol resin, it is preferable that ratio of the number of epoxy groups of all the epoxy resins and the number of phenolic hydroxyl groups of all the phenol resins is 0.8-1.3.

(Where n is an average value and a positive number of 1 to 10)

  The organopolysiloxane having a carboxyl group used in the present invention is an organopolysiloxane having one or more carboxyl groups in one molecule, and needs to be used in combination with polyethylene oxide. When the organopolysiloxane having a carboxyl group is used alone, the releasability becomes insufficient and the continuous moldability is lowered. In the case of using polyethylene oxide alone, the releasability is insufficient, and in order to obtain sufficient releasability, it is necessary to increase the blending amount. Also, the appearance of the molded product is bad. By using in combination with an organopolysiloxane having a carboxyl group and polyethylene oxide, the polyethylene oxide can be compatibilized, and the blending amount of the polyethylene oxide can at least improve the releasability, and can achieve both appearance and releasability. Molding is good and does not cause a decrease in solder heat resistance. The blending ratio is preferably 5/1 to 1/5 in weight ratio, and this range is most effective.

（式中、Ｒは少なくとも１つ以上がカルボキシル基を有する炭素数１〜４０の一価の有機基であり、残余の基は水素、フェニル基、又はメチル基から選ばれる一価の基であり、互いに同一であっても異なっていてもよい。ｎは平均値で、１〜５０の正数である。） The organopolysiloxane having a carboxyl group is preferably an organopolysiloxane represented by the general formula (1). R in the formula of the general formula (1) is a monovalent organic group, and at least one of all organic groups is a monovalent organic group having 1 to 40 carbon atoms having a carboxyl group, and the remaining The organic group is a monovalent group selected from hydrogen, a phenyl group, or a methyl group, and may be the same as or different from each other. When the carbon number of the monovalent organic group having a carboxyl group exceeds the upper limit, the compatibility with the resin is deteriorated and the appearance of the molded product may be deteriorated. Moreover, n in General formula (1) is an average value and is an integer of 1-50. If the value of n exceeds the upper limit value, the viscosity of the oil alone may increase and the fluidity may deteriorate. When the organopolysiloxane represented by the general formula (1) is used, the appearance of the molded product becomes particularly good without causing a decrease in fluidity. Further, by melting and reacting in advance with an epoxy resin and a curing accelerator, mold stains after continuous molding hardly occur and the continuous moldability becomes extremely good. The curing accelerator referred to here may be anything that accelerates the curing reaction between the carboxyl group and the epoxy group resin, and is the same as the curing accelerator that promotes the curing reaction between the epoxy group and the phenolic hydroxyl group, which will be described later. Things can be used. In addition, the carbon number of the monovalent organic group having a carboxyl group of the organopolysiloxane represented by the general formula (1) is the sum of the carbon number of the hydrocarbon group and the carboxyl group in the monovalent organic group. Point to.

(In the formula, R is a monovalent organic group having 1 to 40 carbon atoms, at least one of which has a carboxyl group, and the remaining group is a monovalent group selected from hydrogen, a phenyl group, or a methyl group. And may be the same or different from each other, n is an average value and is a positive number from 1 to 50.)

As for the compounding quantity of the organopolysiloxane which has a carboxyl group, 0.01 to 3 weight% is preferable in all the epoxy resin compositions. If the value is below the lower limit, the effect is insufficient and the appearance of the molded product due to the release agent may not be suppressed. If the value exceeds the upper limit, the appearance of the molded product may be stained by the organopolysiloxane itself.
Moreover, other organopolysiloxane can be used together in the range which does not impair the effect of adding the organopolysiloxane having a carboxyl group used in the present invention.

  The polyethylene oxide used in the present invention has a polar group composed of carboxylic acid or the like and a nonpolar group composed of a long carbon chain. Although it does not specifically limit about the manufacturing method of the polyethylene oxide used by this invention, For example, what is obtained by oxidizing a high density polyethylene etc. are preferable. The dropping point of the oxidized polyethylene wax used in the present invention is preferably 60 to 140 ° C, more preferably 100 to 130 ° C. If the drip point is less than the lower limit, the thermal stability is not sufficient, and seizure of oxidized polyethylene wax occurs during continuous molding, which may deteriorate mold release properties and impair continuous moldability. When the upper limit is exceeded, when the epoxy resin composition is cured, the oxidized polyethylene wax is not sufficiently melted, so that the dispersibility of the oxidized polyethylene wax is reduced. There is a risk of deteriorating the appearance of the cured resin. The average particle size is preferably 0.1 to 100 μm, and if it is less than the lower limit, the compatibility between the oxidized polyethylene wax and the epoxy resin matrix is too good, so that the cured product surface cannot be exuded, and sufficient release imparting effect is obtained. May not be obtained. When the upper limit is exceeded, the oxidized polyethylene wax is segregated, which may cause mold contamination and deterioration of the appearance of the cured resin. The content of the oxidized polyethylene wax is preferably 0.01 to 1% by weight in the epoxy resin composition. If it is less than the lower limit value, the releasability may be insufficient, and if it exceeds the upper limit value, the adhesion to the lead frame member may be impaired, and peeling from the member may occur during the soldering process. Moreover, there exists a possibility of causing deterioration of mold | die stain | pollution | contamination and resin hardened | cured material external appearance.

As long as the effect of adding the polyethylene oxide used in the present invention is not impaired, other release agents may be used in combination. Examples thereof include natural waxes such as carnauba wax, metal salts of higher fatty acids such as zinc stearate, and fatty acid esters.
Moreover, as a compounding quantity of a polyethylene oxide, 0.02-1 weight% is preferable in all the epoxy resin compositions. If it is below the lower limit, sufficient releasability may not be obtained, and if it exceeds the upper limit, adhesion may be lowered.

The epoxy resin composition of the present invention contains an epoxy resin, a phenol curing agent, an organopolysiloxane having a carboxyl group, and polyethylene oxide as essential components, but includes a curing accelerator, an inorganic filler, etc. as other main components. can do.
As a hardening accelerator used for this invention, what is necessary is just to accelerate the hardening reaction of an epoxy group and a phenolic hydroxyl group, and what is generally used for a sealing material can be used. For example, diazabicycloalkenes such as 1,8-diazabicyclo (5,4,0) undecene-7 and derivatives thereof, organic phosphines such as triphenylphosphine and methyldiphenylphosphine, imidazole compounds such as 2-methylimidazole, tetra Examples thereof include tetra-substituted phosphonium and tetra-substituted borates such as phenylphosphonium and tetraphenylborate, and these may be used alone or in combination.

  As an inorganic filler used for this invention, what is generally used for the epoxy resin composition for semiconductor sealing can be used. Examples thereof include fused silica, crystalline silica, talc, alumina, silicon nitride and the like, and the most preferably used is spherical fused silica. These inorganic fillers may be used alone or in combination. These may be surface-treated with a coupling agent. The shape of the inorganic filler is preferably as spherical as possible and the particle size distribution is broad in order to improve fluidity. As for the compounding quantity of an inorganic filler, 78 to 93 weight% is preferable in all the epoxy resin compositions. If the lower limit is not reached, sufficient solder resistance may not be obtained, and if the upper limit is exceeded, sufficient fluidity may not be obtained.

  The epoxy resin composition of the present invention is composed of an epoxy resin, a phenol curing agent, an organopolysiloxane having a carboxyl group, polyethylene oxide, a curing accelerator, and an inorganic filler. Silane coupling agents such as epoxy silane, mercapto silane, amino silane, alkyl silane, ureido silane, vinyl silane, titanate coupling agent, aluminum coupling agent, coupling agent such as aluminum / zirconium coupling agent, coloring of carbon black, etc. And additives such as low-stress additives such as silicone oil and rubber, flame retardants such as brominated epoxy resin, antimony trioxide, aluminum hydroxide, magnesium hydroxide, zinc borate, zinc molybdate, and phosphazene. Difference even if blended Not support.

The epoxy resin composition of the present invention can be obtained by mixing the raw materials sufficiently uniformly using a mixer or the like, then melt-kneading with a hot roll or a kneader, cooling and pulverizing.
The epoxy resin composition of the present invention is used to encapsulate various electronic components such as semiconductor elements, and to manufacture semiconductor devices by conventional molding methods such as transfer molding, compression molding, and injection molding. do it.

Examples of the present invention are shown below, but the present invention is not limited thereto. The blending ratio is parts by weight.
Example 1
Epoxy resin 1: epoxy resin represented by formula (2) (Nippon Kayaku Co., Ltd., NC3000P, softening point 58 ° C., epoxy equivalent 274, hereinafter referred to as E-1)
8.13 parts by weight

Phenol resin 1: epoxy resin represented by formula (3) (Maywa Kasei Co., Ltd., MEH-7851SS, softening point 107 ° C., hydroxyl group equivalent 203, hereinafter referred to as H-1)
5.47 parts by weight

Organopolysiloxane represented by formula (4): Organopolysiloxane 1
0.20 parts by weight

Oxidized polyethylene wax 1 (drop point 120 ° C., average particle size 50 μm) 0.20 parts by weight 1,8-diazabicyclo (5,4,0) undecene-7 (hereinafter referred to as DBU)
0.20 parts by weight Fused spherical silica (average particle size 25 μm) 85.0 parts by weight Coupling agent (γ-glycidoxypropyltrimethoxysilane) 0.40 parts by weight Carbon black 0.40 parts by weight was mixed and heated Using a roll, the mixture was kneaded at 95 ° C. for 8 minutes, cooled and pulverized to obtain an epoxy resin composition. The obtained epoxy resin composition was evaluated by the following methods. The results are shown in Table 1.

Evaluation method Spiral flow: Using a spiral flow measurement mold according to EMMI-1-66, measurement was performed 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. The criteria for the judgment were less than 70 cm as rejected (x), and 70 cm or more as acceptable (◯).

  Continuous formability: 80 pQFP (CuL / F, package outer dimension: 14 mm × 20 mm × 2 mm thickness, pad size: with a mold temperature of 175 ° C., injection pressure of 9.6 MPa, curing time of 70 seconds, using a low-pressure transfer automatic molding machine 6.5 mm × 6.5 mm, chip size 6.0 mm × 6.0 mm) was continuously molded up to 700 shots. Judgment criteria were ◎ for those that could be continuously molded up to 700 shots without any problems such as unfilled, ◯ for those that could be continuously molded up to 500 shots without any problems such as unfilled, and x otherwise.

  Molded Product Appearance and Mold Dirt: Dirt was evaluated visually for the package and mold after 500 and 700 shots in the continuous molding. The package appearance judgment and the mold contamination standard are indicated by “x” when dirty, “◎” when not dirty up to 700 shots, and “◯” when not dirty up to 500 shots.

Solder heat resistance: The package formed by the above continuous molding is post-cured at 175 ° C. for 8 hours, and the resulting package is humidified at 85 ° C. and 85% relative humidity for 168 hours, and then separately soldered at 240 ° C. and 260 ° C. Ten packages each were immersed in the bath for 10 seconds. The package was 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%. The number of packages evaluated was 20. Moreover, the adhesion state of the semiconductor element and the epoxy resin composition interface was observed with an ultrasonic flaw detector. The number of packages evaluated was 20. The criteria for solder crack resistance are: crack generation rate at 240 ° C. and 260 ° C. is 0% and no peeling: ◎, crack generation rate at 240 ° C. is 0% and no peeling: ○, crack or peeling Those in which the occurred were marked as x.

Examples 2-12, Comparative Examples 1-5
According to the composition of Table 1 and Table 2, an epoxy resin composition was obtained in the same manner as in Example 1 and evaluated in the same manner as in Example 1. The results are shown in Tables 1 and 2.
The raw materials used other than Example 1 are shown below.

Epoxy resin 2: biphenyl type epoxy resin (manufactured by Japan Epoxy Resin Co., Ltd., YX-4000, epoxy equivalent 190 g / eq, melting point 105 ° C., hereinafter referred to as E-2)
Epoxy resin 3: Orthocresol novolak type epoxy resin (manufactured by Nippon Kayaku Co., Ltd., EOCN-102062, epoxy equivalent 200 g / eq, softening point 62 ° C., hereinafter referred to as E-3)
Phenol resin 2: paraxylylene-modified novolak-type phenol resin (manufactured by Mitsui Chemicals, XLC-4L, hydroxyl group equivalent 168 g / eq, softening point 62 ° C., hereinafter referred to as H-2)

Organopolysiloxane 2: Organopolysiloxane represented by the formula (5)

Organopolysiloxane 3: Organopolysiloxane represented by the formula (6)

Organopolysiloxane 4: Organopolysiloxane represented by the formula (7)

Molten reaction product A: Bisphenol A type epoxy resin (manufactured by Japan Epoxy Resin, YL-6810, epoxy equivalent 170 g / eq, melting point 47 ° C.) 66.1 parts by weight was heated and melted at 140 ° C. to prepare organopolysiloxane 3 (formula 33.1 parts by weight of the organopolysiloxane represented by (6) and 0.8 parts by weight of triphenylphosphine were added and melt-mixed for 30 minutes to obtain a molten reactant A.
Oxidized polyethylene wax 2 (drop point 110 ° C., average particle size 80 μm)
Oxidized polyethylene wax 3 (drop point 125 ° C., average particle size 5 μm)
Carnauba wax

  According to the present invention, it exhibits excellent solder heat resistance when mounted on a semiconductor device, and problems such as releasability, continuous formability, appearance of molded product, mold contamination, etc., which are conventional defects at the time of sealing molding of semiconductor elements. Therefore, it can be suitably used for manufacturing an industrial resin-sealed semiconductor device, particularly a resin-sealed semiconductor device for surface mounting.

Claims (10)

An epoxy resin composition for encapsulating a semiconductor, comprising (A) an epoxy resin, (B) a phenol resin, (C) an organopolysiloxane having a carboxyl group, and (D) polyethylene oxide. 2. The epoxy resin composition for semiconductor encapsulation according to claim 1, wherein the organopolysiloxane having a carboxyl group (C) is an organopolysiloxane represented by the general formula (1).

(In the formula, R is a monovalent organic group having 1 to 40 carbon atoms, at least one of which has a carboxyl group, and the remaining group is a monovalent group selected from hydrogen, phenyl group, or methyl group. And may be the same or different from each other, n is an average value and is a positive number from 1 to 50.) The epoxy resin composition for semiconductor encapsulation according to claim 1 or 2, wherein the (D) oxidized polyethylene is obtained by oxidizing high density polyethylene. The epoxy resin composition for semiconductor encapsulation according to claim 1, wherein the (D) polyethylene oxide has a maximum particle size of 150 μm or less and an average particle size of 0.1 to 100 μm. The epoxy resin composition for semiconductor encapsulation according to any one of claims 1 to 4, wherein the dropping point of the (D) oxidized polyethylene is 100 to 130 ° C. 6. The epoxy resin for semiconductor encapsulation according to claim 1, wherein the organopolysiloxane having a carboxyl group (C) includes an organopolysiloxane having a carboxyl group that has been reacted with an epoxy resin and a curing accelerator in advance. Composition. The weight ratio (C) / (D) of the (C) carboxyl group-containing organopolysiloxane and the (D) polyethylene oxide is 5/1 to 1/5. Epoxy resin composition for semiconductor encapsulation. The epoxy resin composition for semiconductor encapsulation according to claim 1, wherein the (A) epoxy resin is an epoxy resin represented by the general formula (2).

(Where n is an average value and a positive number of 1 to 10) The epoxy resin composition for semiconductor encapsulation according to claim 1, wherein the (B) phenol resin is a phenol resin represented by the general formula (3).

(Where n is an average value and a positive number of 1 to 10) A semiconductor device comprising a semiconductor element sealed using the epoxy resin composition for semiconductor sealing according to claim 1.