JP2011088949A - Epoxy resin composition and semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an epoxy resin composition having excellent solder resistance, and to provide a semiconductor device. <P>SOLUTION: The epoxy resin composition is used for sealing a semiconductor, and contains (A) an epoxy resin, (B) a curing agent, (C) an inorganic filler and (D) a compound having a cyclic disulfide structure. The semiconductor device is obtained by sealing a semiconductor element by a cured product of the epoxy resin composition. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

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

As a sealing method for semiconductor elements such as IC and LSI, molding sealing with an epoxy resin composition is suitable because it is suitable for mass production at low cost. Further, in terms of reliability, improvement of properties has been achieved by improving epoxy resins and phenol resins as curing agents.
However, due to the recent trend toward smaller, lighter, and higher performance electronic devices, semiconductors have been increasingly integrated and the surface mounting of semiconductor devices has been promoted. The demand for compositions has become increasingly severe. For this reason, the problem which cannot be solved with the conventional epoxy resin composition has also come out.

For example, by adopting surface mounting, the semiconductor device is suddenly exposed to a high temperature of 200 ° C. or higher in the solder dipping or solder reflow process, and the moisture inside the semiconductor device, particularly the semiconductor element, This is a phenomenon in which the reliability of the lead frame and the inner lead is remarkably lowered due to peeling at the interface between various plated joint portions such as gold plating and silver plating and the cured product of the epoxy resin composition.
In addition, with the transition from leaded solder to lead-free solder, which started with environmental problems, the temperature during soldering processing increased, and solder resistance due to explosive stress generated by vaporization of moisture contained in semiconductor devices However, it has become a bigger problem than before.

In order to improve reliability degradation due to solder processing, increase the amount of inorganic filler in the epoxy resin composition to achieve low moisture absorption, high strength, low thermal expansion, improve solder resistance, There is a technique of using a low melt viscosity resin to maintain a high fluidity at a low viscosity during molding (see, for example, Patent Document 1). Although solder resistance is considerably improved by using this method, as the filling rate of the inorganic filler increases, fluidity is sacrificed, and the epoxy resin composition is not sufficiently filled in the package, resulting in voids. There was a drawback that made it easier.
Moreover, in order to prevent peeling at the interface between the plated portion and the cured product of the epoxy resin composition, it has been proposed to increase the adhesion between the metal and the resin with a disulfide compound (see, for example, Patent Document 2). However, sufficient solder resistance has not been achieved. For this reason, there is a need for a further technique for achieving good solder resistance that does not cause peeling or cracking even by high-temperature solder processing corresponding to lead-free solder.

Japanese Patent Laid-Open No. 05-131486 JP 2006-28477 A

  An object of the present invention is to provide an epoxy resin composition and a semiconductor device excellent in solder resistance.

Such an object is achieved by the present invention described in the following (1) to (7).
(1) An epoxy resin composition used for semiconductor encapsulation containing (A) an epoxy resin, (B) a curing agent, (C) an inorganic filler, and (D) a dithioalcohol compound,
The epoxy resin composition, wherein the (D) dithioalcohol compound is represented by the following general formula (1).

(2) The above (1), wherein the (D) dithioalcohol compound is at least one dithioalcohol compound selected from 2,2′-dithiodiethanol, 3,3′-dithiodipropanol and derivatives thereof. The epoxy resin composition described in 1.
(3) The epoxy resin composition according to (1) or (2), wherein the content of the (D) dithioalcohol compound is 0.01% by weight or more and 1% by weight or less of the entire epoxy resin composition. .
(4) The epoxy resin composition according to any one of (1) to (3), further comprising (E) a curing accelerator.
(5) The epoxy resin composition according to any one of (1) to (4), wherein the (A) epoxy resin is an epoxy resin represented by the following general formula (2).

(6) The epoxy resin composition according to any one of (1) to (5), wherein the curing agent (B) is a phenol resin represented by the following general formula (3).

(7) A semiconductor device, wherein a semiconductor element is sealed with a cured product of the epoxy resin composition according to any one of (1) to (6).

  According to the present invention, an epoxy resin composition and a semiconductor device excellent in solder resistance can be obtained.

It is the figure which showed the cross-section about an example of the semiconductor device using the epoxy resin composition which concerns on this invention.

Hereinafter, the epoxy resin composition and semiconductor device of the present invention will be described in detail.
The epoxy resin composition of the present invention, there in (A) epoxy resin, (B) a curing agent, (C) an inorganic filler, an epoxy resin composition used for encapsulating a semiconductor containing the (D) dithio alcohol compound The (D) dithioalcohol compound is represented by the following general formula (1).

  A semiconductor device of the present invention is characterized in that a semiconductor element is sealed with a cured product of the epoxy resin composition described above.

(Epoxy resin composition)
First, the epoxy resin composition will be described. The epoxy resin composition of the present invention is used for sealing a semiconductor element.
The epoxy resin composition contains (A) an epoxy resin (A).
The (A) epoxy resin is a monomer, oligomer or polymer 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.), and these may be used alone or in combination of two or more. Among such epoxy resins, a phenol aralkyl type epoxy resin having a biphenylene skeleton represented by the following general formula (2) is preferable. Thereby, especially flame resistance and solder resistance can be improved.

  The content of the (A) epoxy resin is not particularly limited, but is preferably 2% by weight or more and 10% by weight or less of the whole epoxy resin composition, and is 2.5% by weight or more and 8% by weight or less. More preferably. When the content of the (A) epoxy resin is within the above range, the effect of improving the solder resistance is excellent without impairing the fluidity.

The weight average molecular weight of the epoxy resin is not particularly limited, but is preferably 100 to 2,000, and particularly preferably 200 to 1,000. When the weight average molecular weight is within the above range, the fluidity is particularly excellent.
The weight average molecular weight is, for example, G.M. P. Using C, evaluation can be performed under the following conditions.
The GPC device is composed of a pump, an injector, a guard column, a column, and a detector, and tetrahydrofuran (THF) is used as a solvent. The pump flow rate is 0.5 ml / min. A flow rate higher than this is not preferable because the detection accuracy of the target molecular weight is lowered. In addition, in order to accurately measure at the above flow rate, it is necessary to use a pump with good flow rate accuracy, and the flow rate accuracy is preferably 0.10% or less. A commercially available guard column (for example, TSK GUARDCOLUMN HHR-L: diameter 6.0 mm, tube length 40 mm) manufactured by Tosoh Corporation, and a commercially available polystyrene gel column (TSK-GEL GMHHR- manufactured by Tosoh Corporation) are used for the guard column. L: diameter 7.8 mm, tube length 30 mm) are connected in series. A differential refractometer (RI detector, for example, a differential refractive index (RI) detector W2414 manufactured by WATERS) is used as the detector. Prior to the measurement, the guard column, the column and the inside of the detector are stabilized at 40 ° C. As a sample, a THF solution of an epoxy resin (A) adjusted to a concentration of 3 to 4 mg / ml is prepared, and this is injected from an about 50 to 150 μl injector to perform measurement. In analyzing the sample, a calibration curve prepared from a monodisperse polystyrene (hereinafter referred to as PS) standard sample is used. For the calibration curve, a logarithmic value of the molecular weight of PS and the peak detection time (retention time) of PS are plotted, and a regression of the cubic equation is used. As standard PS samples for preparing calibration curves, Shodex Standard SL-105 series product numbers S-1.0 (peak molecular weight 1,060), S-1.3 (peak molecular weight 1,310) manufactured by Showa Denko KK , S-2.0 (peak molecular weight 1,990), S-3.0 (peak molecular weight 2,970), S-4.5 (peak molecular weight 4,490), S-5.0 (peak molecular weight 5, 030), S-6.9 (peak molecular weight 6,930), S-11 (peak molecular weight 10,700), S-20 (peak molecular weight 19,900) are used.

  The epoxy resin composition contains (B) a curing agent. The (B) curing agent is not particularly limited as long as it is cured by reacting with an epoxy resin. Specific examples thereof include phenolic resins, bisphenol compounds such as bisphenol A, maleic anhydride, phthalic anhydride, Examples include acid anhydrides such as pyromellitic anhydride and aromatic amines such as metaphenylenediamine, diaminodiphenylmethane, and diaminodiphenylsulfone. These may be used alone or in combination of two or more curing agents.

  Among these curing agents, it is particularly preferable to use a phenolic resin. The phenolic resin used in the present invention is a monomer, oligomer or polymer in general having two or more phenolic hydroxyl groups in one molecule, and its molecular weight and molecular structure 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.), etc. You can use more than one species together. Among such phenol resins, a phenol aralkyl resin having a biphenylene skeleton represented by the following general formula (3) is preferable. Thereby, especially flame resistance and solder resistance can be improved.

  The content of the curing agent (B) is not particularly limited, but is preferably 1% by weight or more and 8% by weight or less, and preferably 2% by weight or more and 6% by weight or less of the entire epoxy resin composition. Is more preferable. When the content of the (B) curing agent is within the above range, the effect of improving the solder resistance is excellent without impairing the fluidity.

  The blending ratio of the (A) epoxy resin and the (B) phenolic resin as the curing agent is a ratio of the number of epoxy groups (Ep) of all epoxy resins to the number of phenolic hydroxyl groups (Ph) of all phenolic resins ( Ep / Ph) is preferably 0.8 or more and 1.3 or less, and particularly preferably 0.9 or more and 1.25 or less. When the ratio is within the above range, the curability of the epoxy resin composition can be improved, and the glass transition temperature of the cured product can be increased. It also has excellent moisture resistance reliability.

  The epoxy resin composition includes (C) an inorganic filler. As said (C) inorganic filler, 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 of two or more.

The average particle diameter of the (C) inorganic filler is not particularly limited, but is preferably 5 μm or more and 50 μm or less, and particularly preferably 10 μm or more and 45 μm or less. When the average particle size is in the above range, the epoxy resin composition is excellent in fluidity. Further, when the average particle diameter is less than the lower limit value, the fluidity may be lowered, and when the average particle diameter is more than the upper limit value, the filling property may be lowered during molding.
The average particle diameter can be evaluated by, for example, a laser diffraction particle size distribution measuring apparatus. (Manufactured by Shimadzu Corporation, SALD-7000)

  The content of the (C) inorganic filler is not particularly limited, but is preferably 75% by weight or more and 94% by weight or less, and particularly preferably 80% by weight or more and 92% by weight or less of the entire epoxy resin composition. When the content is within the above range, the effect of improving the solder resistance is excellent without causing a decrease in fluidity.

  The said epoxy resin composition contains the dithio alcohol compound shown by the said General formula (1). Thereby, solder resistance can be improved.

The reason why the solder resistance can be improved by using the dithioalcohol compound represented by the general formula (1) is considered as follows.
The dithioalcohol compound is stable and does not react in the process of producing the epoxy resin composition, and the SS bond is cleaved when approaching the lead frame metal (particularly when the surface is gold) during molding, Combines with metal. Therefore, it can act efficiently at the interface between the epoxy resin composition and the lead frame. Accordingly, the adhesion at the interface with the metal can be further improved. On the other hand, for example, in the case of a compound having a thiol, it reacts with the resin in the process of producing the epoxy resin composition, so the effect on the metal surface is reduced.
In addition, the alcoholic hydroxyl group is inferior to the initial adhesiveness compared to those that are strongly bonded to the resin, such as amino groups, carboxyl groups, silanol groups, etc. used elsewhere, but heat, moisture absorption, etc. Due to the movement (stress) of the resin due to, the decrease in adhesion is small.

  Although carbon number m of the said dithio alcohol compound is an integer of 2-10, More preferably, it is an integer of 2-5, Most preferably, it is an integer of 2-3. When the number of carbons exceeds the upper limit, the molecular weight is increased, whereby the viscosity is improved and the fluidity may be lowered. Moreover, when carbon number is less than the said lower limit, it may volatilize when melt-kneading.

  Moreover, although carbon number n of the said dithio alcohol compound is an integer of 1-10, More preferably, it is an integer of 1-5, Most preferably, it is an integer of 1-3. When the number of carbons exceeds the upper limit, the molecular weight is increased, whereby the viscosity is improved and the fluidity may be lowered. Moreover, when carbon number is less than the said lower limit, it may volatilize when melt-kneading.

  More specifically, the dithioalcohol compound has m of 2 to 4 carbon atoms, preferably n of 1 to 4, particularly m of 2 to 3, and n of 2 to 3. Preferably there is. When the carbon number is within the above range, the effect of improving the adhesion (or solder resistance) to the lead frame is particularly excellent.

  More specifically, the dithioalcohol compound is preferably at least one dithioalcohol compound selected from 2,2'-dithiodiethanol, 3,3'-dithiodipropanol and derivatives thereof. Thereby, the adhesiveness (or solder resistance) to the lead frame can be improved.

  The content of the (D) dithioalcohol compound is not particularly limited, but is preferably 0.01% by weight or more and 1% by weight or less of the entire epoxy resin composition, and particularly 0.1% by weight or more and 0.4% by weight. % Or less is preferable. If the content of the dithioalcohol compound is below the lower limit, the effect of improving the adhesion may be reduced, and if the content exceeds the upper limit, the strength of the molded product is reduced and the effect of improving the reliability of the package is reduced. There is a case.

Although the said epoxy resin composition is not specifically limited, It is preferable that (E) hardening accelerator is included further. Thereby, reaction of an epoxy resin and a hardening | curing agent can be accelerated | stimulated and it can have favorable fluidity | liquidity and sclerosis | hardenability.
As said (E) hardening accelerator, what accelerates | stimulates the reaction of the epoxy group of an epoxy resin and a hardening | curing agent (for example, phenolic hydroxyl group of a phenol-type resin) is sufficient, and it is a sealing material of a semiconductor element generally. What is used for the epoxy resin composition can be utilized. Specific examples include organic phosphines, tetra-substituted phosphonium compounds, phosphobetaine compounds, phosphorus atom-containing compounds such as adducts of phosphine compounds and quinone compounds, 1,8-diazabicyclo (5,4,0) undecene-7, benzyl Nitrogen atom-containing compounds such as dimethylamine and 2-methylimidazole can be mentioned. These curing accelerators may be used alone or in combination of two or more. Among these, a phosphorus atom-containing compound is preferable, and a tetra-substituted phosphonium compound is preferable in consideration of fluidity, and a phosphobetaine compound in consideration of lowering a modulus of elasticity of a cured product of an epoxy resin composition at a high temperature. An adduct of a phosphine compound and a quinone compound is more preferable.

  Examples of the organic phosphine include a first phosphine such as ethylphosphine and phenylphosphine, a second phosphine such as dimethylphosphine and diphenylphosphine, and a third phosphine such as trimethylphosphine, triethylphosphine, tributylphosphine, and triphenylphosphine.

  Examples of the tetra-substituted phosphonium compound include compounds represented by the following general formula (4).

  The compound represented by the general formula (4) is obtained, for example, as follows. First, a tetra-substituted phosphonium bromide, an aromatic organic acid, and a base are mixed in an organic solvent and mixed uniformly to generate an aromatic organic acid anion in the solution system. Then add water. Then, the compound represented by the general formula (4) can be precipitated. In the compound represented by the general formula (4), R7, R8, R9 and R10 bonded to the phosphorus atom are phenyl groups, and AH is a compound having a hydroxyl group in an aromatic ring, that is, phenols, and A Is preferably an anion of the phenol.

  Examples of the phosphobetaine compound include compounds represented by the following general formula (5).

  The compound represented by the general formula (5) is obtained, for example, as follows. First, it is obtained through a step of bringing a triaromatic substituted phosphine, which is a third phosphine, into contact with a diazonium salt and replacing the triaromatic substituted phosphine with a diazonium group of the diazonium salt. However, the present invention is not limited to this. As the compound represented by the general formula (5), for example, those in which X is hydrogen or a methyl group and Y is hydrogen or a hydroxyl group are preferable.

  Examples of the adduct of the phosphine compound and the quinone compound include compounds represented by the following general formula (6).

Examples of phosphine compounds used as adducts of phosphine compounds and quinone compounds include aromatic rings such as triphenylphosphine, tris (alkylphenyl) phosphine, tris (alkoxyphenyl) phosphine, trinaphthylphosphine, and tris (benzyl) phosphine. Those which are unsubstituted or have a substituent such as an alkyl group or an alkoxyl group are preferable, and examples of the organic group of the alkyl group and the alkoxyl group include those having 1 to 6 carbon atoms. From the viewpoint of availability, triphenylphosphine is preferable.
Moreover, as a quinone compound used for the adduct of a phosphine compound and a quinone compound, o-benzoquinone, p-benzoquinone, and anthraquinones are mentioned, for example, p-benzoquinone is preferable from the point of storage stability.
As a method for producing an adduct of a phosphine compound and a quinone compound, the adduct can be obtained by contacting and mixing in a solvent capable of dissolving both the organic tertiary phosphine and the quinone compound. The solvent is preferably a ketone such as acetone or methyl ethyl ketone, which has low solubility in the adduct. However, the present invention is not limited to this.
In the compound represented by the general formula (6), R11, R12 and R13 bonded to the phosphorus atom are phenyl groups, and R14, R15 and R16 are hydrogen atoms, that is, 1,4-benzoquinone and triphenyl A compound to which phosphine is added is preferable.

  Although the compounding quantity of the said hardening accelerator (E) is not specifically limited, 0.1 to 1 weight% of the whole epoxy resin composition is preferable. When the blending amount is within the above range, good curability can be obtained without impairing fluidity.

  Moreover, silane coupling agents, such as an epoxy silane, a mercapto silane, an amino silane, an alkyl silane, a ureido silane, a vinyl silane, can be used for the said epoxy resin composition as needed. Specific examples of the compound include γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, N- (β-aminoethyl) -γ-aminopropyltrimethoxysilane, N- (β-aminoethyl)- γ-aminopropylmethyldimethoxysilane, N-phenyl-γ-aminopropyltriethoxysilane, N-phenylγ-aminopropyltrimethoxysilane, N- (β-aminoethyl) -γ-aminopropyltriethoxysilane, N- (6-Aminohexyl) -3-aminopropyltrimethoxysilane, N- (3-trimethoxysilylpropyl) -1,3-benzenedimethanamine, γ-glycidoxypropyltriethoxysilane, γ-glycidoxy Propyltrimethoxysilane, γ-glycidoxypropylmethyldimethoxysilane beta-(3,4-epoxycyclohexyl) ethyltrimethoxysilane, .gamma.-mercaptopropyltrimethoxysilane, methyltrimethoxysilane down, .gamma.-ureidopropyltriethoxysilane, and vinyl triethoxysilane. Of these, epoxy silane, mercapto silane, and amino silane are preferable. As the amino silane, primary amino silane or anilino silane is preferable. In addition, it is more effective to use two or more of these in combination, and it is particularly preferable to use anilinosilane in combination with epoxy silane, mercaptosilane, or primary aminosilane. Is most preferred.

  The blending amount of such a silane coupling agent is not particularly limited, but is preferably 0.01% by weight or more and 1.5% by weight or less of the whole epoxy resin composition, particularly 0.03% by weight or more and 1% by weight. % Or less is preferable. When the blending amount of the silane coupling agent is within the above range, further lowering of viscosity and improvement in fluidity can be expected. Moreover, if it is in the said range, it will be excellent in the adhesive improvement effect, without reducing sclerosis | hardenability. In addition, these silane coupling agents may be used after being hydrolyzed by adding water or an acid or an alkali as necessary, or may be previously treated with an inorganic filler.

  A release agent is used in the epoxy resin composition as necessary. As the mold release agent, conventionally known ones can be used, and examples thereof include higher fatty acids, higher fatty acid metal salts, ester waxes, polyethylene waxes, and the like. You may use together a seed or more. Of these, polyethylene waxes are preferable, and it is more preferable to use polyethylene wax and montanic acid ester wax in combination. The compounding amount of the release agent is not particularly limited, but is preferably 0.05% by weight or more and 3% by weight or less, more preferably 0.1% by weight or more and 1% by weight or less of the entire epoxy resin composition. If the blending amount is less than the lower limit value, the releasability may be lowered, and if it exceeds the upper limit value, adhesion and solder resistance may be lowered.

  An ion trap agent is used for the epoxy resin composition as necessary. As the ion trapping agent, conventionally known ones can be used. Examples thereof include hydrotalcites and hydrated oxides of elements selected from magnesium, aluminum, bismuth, titanium, and zirconium. It may be used alone or in combination of two or more. Of these, hydrotalcites are preferred. The compounding amount of the ion trapping agent is not particularly limited, but is preferably 0.05% by weight or more and 3% by weight or less, more preferably 0.1% by weight or more and 1% by weight or less of the entire epoxy resin composition. When the blending amount is within the above range, sufficient ion scavenging action is exhibited and there is little adverse effect on other material properties.

  The epoxy resin composition includes an epoxy resin, a phenol resin, a curing accelerator, an inorganic filler, a dithioalcohol compound, a silane coupling agent, a release agent and an ion trap agent, a colorant such as carbon black, a silicone oil Additives such as low stress additives such as rubber, flame retardants such as brominated epoxy resin, antimony trioxide, aluminum hydroxide, magnesium hydroxide, zinc borate, zinc molybdate, phosphazene, etc. .

  The epoxy resin composition is suitably mixed as necessary, for example, a mixture of raw materials sufficiently uniformly using, for example, a mixer, a melt kneaded with a hot roll or a kneader, and then pulverized after cooling. What adjusted dispersity etc. can be used.

(Semiconductor device)
The epoxy resin composition as described above is used to seal various electronic components such as semiconductor elements and to manufacture a semiconductor device, and is cured by a conventional molding method such as transfer molding, compression molding, injection molding, etc. A semiconductor device can be obtained by molding.

The semiconductor element that performs sealing in the present invention is not particularly limited, and examples thereof include an integrated circuit, a large-scale integrated circuit, a transistor, a thyristor, a diode, and a solid-state imaging element.
The form of the semiconductor device of the present invention is not particularly limited. For example, the dual in-line package (DIP), the plastic lead chip carrier (PLCC), the quad flat package (QFP), the small outline, and the like. Package (SOP), Small Outline J Lead Package (SOJ), Thin Small Outline Package (TSOP), Thin Quad Flat Package (TQFP), Tape Carrier Package (TCP), Ball Grid Examples include an array (BGA), a chip size package (CSP), and the like.
A semiconductor device sealed by a molding method such as a transfer mold is mounted on an electronic device or the like as it is or after being completely cured at a temperature of about 80 ° C. to 200 ° C. for about 10 minutes to 10 hours. Is done.

  FIG. 1 is a view showing a cross-sectional structure of an example of a semiconductor device using the epoxy resin composition for semiconductor encapsulation according to the present invention. The semiconductor element 1 is fixed on the die pad 3 via the die bond material cured body 2. The electrode pad of the semiconductor element 1 and the lead frame 5 are connected by a gold wire 4. The semiconductor element 1 is sealed with a cured body 6 of a sealing resin composition.

Hereinafter, the present invention will be described in detail based on Examples and Comparative Examples, but the present invention is not limited thereto. The blending ratio was parts by weight.
Example 1
Epoxy resin 1: epoxy resin represented by the general formula (2) as an epoxy resin (phenol aralkyl type epoxy resin having a biphenylene skeleton: manufactured by Nippon Kayaku Co., Ltd., trade name NC3000P, softening point 58 ° C., epoxy equivalent 273, n = 2.3) 6.3 parts by weight and phenol resin 1: phenol aralkyl resin having a biphenylene skeleton represented by general formula (3) (Maywa Kasei Co., Ltd., trade name MEH-7801SS) Softening point 65 ° C., hydroxyl group equivalent 204, m = 1.6) in formula (2) 4.3 parts by weight, curing accelerator: 0.2 part by weight of adduct of triphenylphosphine and 1,4-benzoquinone , 88.0 parts by weight of fused spherical silica (average particle size 30 μm), and 2,2′-dithiodiethanano as compound (D) having a dithioalcohol structure 0.1 parts by weight of Le (Tokyo Chemical Industry Co., Ltd., molecular weight: 154.25) and 0.2 parts by weight of coupling agent 1: N-phenyl-γ-aminopropyltrimethoxysilane as a silane coupling agent , 0.3 parts by weight of polyethylene wax (release agent 1) as a release agent, 0.2 parts by weight of hydrotalcite (DHT-4H, manufactured by Kyowa Chemical Industry Co., Ltd.) as an ion trap agent, and carbon black 0.4 parts by weight was mixed with a mixer, kneaded at 95 ° C. for 8 minutes using a hot roll, cooled and pulverized to obtain an epoxy resin composition.

(Example 2)
The same procedure as in Example 1 was conducted except that 3,3′-dithiodipropanol was used as the compound (D) having a dithioalcohol structure.

(Example 3)
The procedure of Example 1 was repeated except that the amount of 2,2′-dithiodiethanol added was reduced and the formulation was as shown in Table 1.

(Example 4)
The procedure of Example 1 was repeated except that the amount of 2,2′-dithiodiethanol added was increased and the formulation was changed as shown in Table 1.

(Example 5)
Example 1 was repeated except that the following epoxy resin was used.
Epoxy resin 2: Biphenyl type epoxy resin (Japan Epoxy Resin Co., Ltd., trade name YX-4000, epoxy equivalent 190, melting point 105 ° C.).

(Example 6)
Example 1 was repeated except that the following phenol resin was used.
Phenol resin 2: Phenol aralkyl resin (Mitsui Chemicals, trade name XLC-LL, hydroxyl group equivalent 165, softening point 79 ° C.).

(Comparative Example 1)
Except for the dithioalcohol compound (D), the procedure was the same as Example 1 except that the formulation was as shown in Table 1.

(Comparative Example 2)
It was carried out similarly to Example 1 except having used disulfide silane (Nippon Unicar Co., Ltd. product: A1289) instead of the dithio alcohol compound (D).

(Comparative Example 3)
Example 1 was repeated except that dithioglycolic acid (manufactured by Wako Pure Chemical Industries, Ltd.) was used instead of the dithioalcohol compound (D).

  Using the epoxy resin compositions obtained in each Example and Comparative Example, evaluation was performed by the following method. The results are shown in Table 1.

1. Solder resistance 1
Using a low-pressure transfer molding machine (Daiichi Seiko Co., Ltd., GP-ELF), a silicon chip or the like is sealed with an epoxy resin composition under conditions of a molding temperature of 175 ° C., a pressure of 8.3 MPa, and a curing time of 120 seconds. 80 pin QFP (Quad Flat Package, Cu Ni-Pd-Au plating frame, package size: 14 mm x 20 mm x 2 mm thickness, chip size 6.0 mm x 6.0 mm x 0.35 mm thickness) Heat treatment was performed at 175 ° C. for 8 hours as an afterbake. Then, after performing the humidification process for 120 hours at 60 degreeC and 60% of relative humidity, the IR reflow process of 260 degreeC was performed. Peeling and cracks inside the package were confirmed with an ultrasonic flaw detector (manufactured by Hitachi Construction Machinery Finetech Co., Ltd., mi-scope hyper II), and any one of either peeling or cracking was regarded as defective. The number of defective packages among the 10 packages evaluated is shown.

2. Solder resistance 2
Using a low-pressure transfer molding machine (Daiichi Seiko Co., Ltd., GP-ELF), a silicon chip or the like is sealed with an epoxy resin composition under conditions of a molding temperature of 175 ° C., a pressure of 8.3 MPa, and a curing time of 120 seconds. 80 pin QFP (Quad Flat Package, Cu Ni-Pd-Au plating frame, package size: 14 mm x 20 mm x 2 mm thickness, chip size 6.0 mm x 6.0 mm x 0.35 mm thickness) Heat treatment was performed at 175 ° C. for 8 hours as an afterbake. Then, after performing the humidification process for 168 hours at 85 degreeC and 60% of relative humidity, 260 degreeC IR reflow process was performed. Peeling and cracks inside the package were confirmed with an ultrasonic flaw detector (manufactured by Hitachi Construction Machinery Finetech Co., Ltd., mi-scope hyper II), and any one of either peeling or cracking was regarded as defective. The number of defective packages among the 10 packages evaluated is shown.

As is clear from Table 1, the semiconductor package molded using the epoxy compositions obtained in Examples 1 to 6 was excellent in solder resistance.
In particular, Examples 1 and 2 were excellent in solder resistance under more severe conditions.

  According to the present invention, since an epoxy resin composition for semiconductor encapsulation having good solder resistance that does not cause peeling or cracking even by a high-temperature soldering process corresponding to lead-free solder can be obtained, particularly in a surface-mounted semiconductor device It can be suitably used for production.

DESCRIPTION OF SYMBOLS 1 Semiconductor element 2 Die-bonding material hardening body 3 Die pad 4 Gold wire 5 Lead frame 6 Hardening body of resin composition for sealing

Claims (7)

(A) an epoxy resin, (B) a curing agent, (C) an inorganic filler, and (D) a dithioalcohol compound, and an epoxy resin composition used for semiconductor encapsulation,
The epoxy resin composition, wherein the (D) dithioalcohol compound is represented by the following general formula (1).

  The epoxy according to claim 1, wherein the (D) dithioalcohol compound is at least one dithioalcohol compound selected from 2,2'-dithiodiethanol, 3,3'-dithiodipropanol and derivatives thereof. Resin composition.   3. The epoxy resin composition according to claim 1, wherein the content of the (D) dithioalcohol compound is 0.01 wt% or more and 1 wt% or less of the entire epoxy resin composition.   The epoxy resin composition according to any one of claims 1 to 3, further comprising (E) a curing accelerator. The epoxy resin composition according to any one of claims 1 to 4, wherein the (A) epoxy resin is an epoxy resin represented by the following general formula (2).

The epoxy resin composition according to any one of claims 1 to 5, wherein the curing agent (B) is a phenol resin represented by the following general formula (3).

  A semiconductor device, wherein a semiconductor element is sealed with a cured product of the epoxy resin composition according to claim 1.

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