JPH10298408A - Epoxy resin composition and semiconductor device sealed therewith - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an epoxy resin composition excellent in soldering stress resistance and high-temperature storage stability and a semiconductor device sealed therewith. SOLUTION: This invention provides an epoxy resin composition comprising an epoxy resin, a phenolic resin curing agent, a cure accelerator, a surface treating agent, a flame retardant, 0.1-5 wt.%, based on the total epoxy resin composition, at least one flame retardant aid selected from diantimony tetraoxide and diantimony pentoxide, 80-95 wt.% inorganic filler being amorphous silica and 0.1-5 wt.% compound represented by the formula: Mgx Zny Alz (OH)2x+2y+3z-2n (CO3 )n .nH2 O [wherein x, y, z and m satisfy the following relationships, and n is 0 or a positive number. 0<z/(x+y)<=1; 0<y/x<=1; x≠0; y≠0; and 0<=m/z<1.5] and a semiconductor device sealed therewith.

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 using the composition. Particularly, in a semiconductor package, a thin QFP having a package thickness of 2.0 mm or less, It is used for SOP and the like.

[0002]

2. Description of the Related Art Conventionally, diodes, transistors, I
Electronic components or semiconductor elements such as C and LSI are mainly encapsulated with an epoxy resin composition. In particular, in integrated circuits such as IC and LSI, ortho-cresol novolac type epoxy resin having excellent heat resistance and moisture resistance is converted to phenol. An epoxy resin composition cured with a novolak resin and blended with an inorganic filler such as fused silica or crystalline silica as a filler is used. However, with the recent increase in the degree of integration of integrated circuits, semiconductor chips have become larger, and packages have become
Small and thin QF surface mounted from P type
P, SOP, SOJ, TSOP, TQFP, PLCC, etc. have been changed. That is, by encapsulating a large chip in a small and thin package, cracks are generated due to thermal stress, and a decrease in moisture resistance due to the cracks has become a serious problem. In particular, during the soldering process, the package is rapidly exposed to a high temperature of 200 ° C. or more, which causes a problem that the package is cracked or the interface between the chip and the sealing resin is peeled off and the moisture resistance is reduced. ing.

[0003] In order to reduce the thermal stress in the above-mentioned soldering process, a method of reducing the elastic modulus of a cured product of the epoxy resin composition when heated has been studied. This will lower the transition temperature (hereinafter referred to as Tg). Especially when Tg is less than 150 ° C,
The high-temperature storage characteristics evaluated at a temperature of 150 ° C. or more are significantly reduced, and there is a concern that the reliability of the package may be reduced. As a technique for improving the high-temperature storage characteristics, studies on bromo compounds and antimony compounds contained in the epoxy resin composition (for example, JP-A-61-143664, JP-A-61-163922, etc.), and antimony compounds (For example, regarding the type of antimony oxide, see JP-A-56-129245, JP-A-61-5
3321) and further studies of hydrotalcite-based compounds (for example, JP-A-63-252451, JP-A-1-206656, JP-A-1-64243, JP-A-5-25365, etc. ). However, although these proposals are all techniques for improving the high-temperature storage characteristics to some extent, they have not reached a dramatic improvement.

[0004]

SUMMARY OF THE INVENTION The present invention has been made as a result of various studies for achieving both heat resistance and high-temperature storage characteristics in a soldering process. An object of the present invention is to provide an epoxy resin composition for semiconductor encapsulation, in which package crack resistance and high-temperature storage characteristics in a process are remarkably improved and both characteristics are compatible, and a semiconductor device encapsulated using the composition.

[0005]

SUMMARY OF THE INVENTION The present invention provides an epoxy resin, a phenol resin curing agent, a curing accelerator, a surface treatment agent,
0.1 to 5% by weight of (a) at least one selected from diantimony tetroxide and diantimony pentoxide as a flame retardant aid in the flame retardant and the total epoxy resin composition;
(B) 80 to 95% by weight of amorphous silica as an inorganic filler, and (c) 0.1% of a compound represented by the following formula (1).
An epoxy resin composition containing the epoxy resin composition having a glass transition temperature of 90 to 150 ° C. by a thermomechanical analyzer. This is a semiconductor device sealed by sealing. Mg _x Zn _y Al _z (OH) _{2x + 2y + 3z-2m} (CO ₃ ) _m · nH ₂ O (1) [where x, y, z, and m are represented by the following relationships, and n is Indicates 0 or a positive number. 0 <z / (x + y) ≦ 1, 0 <y
/ X ≦ 1, x ≠ 0, y ≠ 0, 0 ≦ m / z <1.5]

The epoxy resin used in the present invention includes monomers, oligomers, and polymers in general, and includes, for example, a biphenyl type epoxy compound, a stilbene type epoxy compound, a bisphenol type epoxy compound, a phenol novolak type epoxy resin, a cresol novolak type epoxy resin, and It generally refers to those having an epoxy group such as pentadiene-modified epoxy resin. The phenolic resin curing agent used in the present invention includes monomers, oligomers, and polymers in general, and examples thereof include phenol novolak resins, cresol novolak resins, dicyclopentadiene-modified phenol resins, xylylene-modified phenol resins, and triphenolmethane-type compounds. The phenolic hydroxyl group of the phenol resin reacts with the epoxy group of the epoxy resin to form a crosslinked structure. The equivalent ratio of the epoxy group of the epoxy resin to the phenolic hydroxyl group of the phenolic resin is preferably 0.5 to 2, and if it falls outside this range, the curability of the resin composition will decrease and the Tg of the cured product will decrease. There is a risk.

The inorganic filler used in the present invention is amorphous silica, and may be amorphous silica or spherical silica.
The amorphous silica preferably contains 80 to 95% by weight of the total resin composition. When the content is less than 80% by weight, the organic matter in the resin composition relatively increases, so that the amount of water absorption increases, and sufficient characteristics for solder crack resistance cannot be obtained. or,
If it exceeds 95% by weight, sufficient fluidity required for molding cannot be obtained. Note that another inorganic filler such as crystalline silica may be added as long as the effect of adding the amorphous silica is not impaired.

[0008] Further, a thermomechanical analyzer (hereinafter referred to as TMA) of the resin composition of the present invention.
Is preferably 90 to 150 ° C., and if it exceeds 150 ° C., it is difficult to relax thermal stress during soldering. As a result, a package crack occurs. Insufficient strength and hardness of the molded product causes poor mold release, and also impairs high-temperature storage characteristics. Tg in the present invention is 4 mm × 5 mm × 15 m at a molding temperature of 175 ° C. and a curing time of 120 seconds.
m and a post-cured test piece at 175 ° C. for 8 hours were measured using a thermomechanical analyzer [TMA100, manufactured by Seiko Denshi Kogyo Co., Ltd.].
Α ₁ and α ₂ are determined from the measurement chart when the temperature is measured at a temperature rise rate of 5 ° C./min at 320 ° C., and the intersection of the extension lines is determined.

The curing accelerator used in the present invention is a catalyst which promotes a crosslinking reaction between an epoxy resin such as imidazoles such as 2-methylimidazole, tertiary amines, phosphine compounds and organoaluminum compounds and a phenol resin curing agent. General. The compounding amount in the entire epoxy resin composition is preferably 0.02 to 0.5% by weight. The surface treatment agent used in the present invention refers to an inorganic filler modifier such as a silane coupling agent and a titanium coupling agent. The compounding amount in the entire epoxy resin composition is preferably from 0.1 to 2.0% by weight.

The flame retardant used in the present invention is a brominated epoxy resin, and refers to all brominated epoxy resins such as a brominated bisphenol type epoxy resin and a brominated phenol novolak type epoxy resin. The compounding amount in the entire epoxy resin composition is preferably from 0.1 to 0.5% by weight. The flame retardant aid used in the present invention refers to diantimony tetroxide or diantimony pentoxide. Diantimony pentoxide and diantimony pentoxide may be used alone or as a mixture. Antimony pentoxide may be a hydrated compound. It is preferable that the amount of these components is 0.1 to 5% by weight based on the total epoxy resin composition. If the content is less than 0.1% by weight, the flame retardancy which is an essential property of the epoxy resin composition cannot be obtained, which is not preferable. On the other hand, 5% by weight
If it exceeds 300, the atomic weight of antimony contained in all the epoxy resin compositions increases, and the moisture resistance and the high-temperature storage characteristics decrease significantly, which is not preferable.

The amount of the compound represented by the following formula (1) used in the present invention is 0.1 to 5% by weight, preferably 0.2 to 5% by weight.
3% by weight. If the addition amount is less than 0.1% by weight, the effect of improving the high-temperature storage characteristics is insufficient, and if it exceeds 5% by weight, the moldability deteriorates and practical problems occur. Mg _x Zn _y Al _z (OH) _{2x + 2y + 3z-2m} (CO ₃ ) _m · nH ₂ O (1) [where x, y, z, and m are represented by the following relationships, and n is Indicates 0 or a positive number. 0 <z / (x + y) ≦ 1, 0 <y
/ X ≦ 1, x ≠ 0, y ≠ 0, 0 ≦ m / z <1.5] The compound represented by the formula (1) is a kind of a compound generally called a hydrotalcite compound, and its composition It is characterized by containing a zinc atom.

The generally reported hydrotalcite-based compound is of the type not containing a zinc atom as in formula 2, but the metal ion radius is increased by substituting a part of the magnesium atom with a zinc atom. It is characterized in that the effect of capturing halogen atoms (especially bromine atoms) is enhanced. Mg _x Al _y (OH) _{2x + 3y-2z} (CO ₃ ) _z · mH ₂ O (2) [where x, y, and z are represented by the following relations, respectively.
Represents 0 or a positive number. 0 <y / x ≦ 1, 0 ≦ z / y <1.5]

Preferred specific examples of the compound represented by the above formula 1 used in the present invention are: Mg _3.5 Zn _1.0 Al ₂ (OH) ₁₃ CO _{3 3.5} H ₂ O Mg _3.5 Zn _1.0 Al ₂ (OH) ₁₃ CO ₃ .Mg _4.0 Zn _1.0 Al _1.5 (OH) ₁₃ CO ₃ .Mg _3.5 Zn _2.5 Al ₂ (OH) ₁₆ CO ₃ .4H ₂ O.

In the present invention, in addition to an epoxy resin, a phenol resin curing agent, an inorganic filler, a curing accelerator, a surface treatment agent, a flame retardant and a flame retardant auxiliary, if necessary, low stress such as silicone rubber, silicone oil, etc. And a coloring agent such as carbon black. To produce the epoxy resin composition of the present invention as a molding material, an epoxy resin, a phenol resin curing agent, an inorganic filler, a curing accelerator, a surface treatment agent, a flame retardant and a flame retardant auxiliary, and other additives are mixed with a mixer. After sufficiently mixing at room temperature, the mixture is further melt-kneaded with a hot roll or a kneader, cooled, and pulverized to obtain a sealing material.

[0015]

The present invention will be specifically described below with reference to examples.
Raw materials used in Examples and Comparative Examples are as follows.・ Epoxy resin A: YX4000 [Yukaka Epoxy Co., Ltd.] (melting point: 106 ° C., epoxy equivalent: 190 g / eq) ・ Epoxy resin B: HP-7200 [Dainippon Ink and Chemicals, Inc.] (softening point: 60 ° C., Epoxy equivalent 260 g / eq) Epoxy resin C: ESCN-195-LA [Sumitomo Chemical Industries, Ltd.] (Softening point 65 ° C, epoxy equivalent 200 g / eq) Curing agent D: Phenol novolak resin [Sumitomo Durez Co., Ltd.] (Softening point 90 ° C., hydroxyl equivalent 104 g / eq) Curing agent E: Phenol aralkyl resin [Mitsui Toatsu Chemical Co., Ltd.] (Softening point 80 ° C., hydroxyl equivalent 175 g / eq) Brominated epoxy resin F: epiclone 153 [Dainippon Ink and Chemicals, Inc.] (Softening point 70 ° C., epoxy equivalent 400 g / eq, bromine content 48% by weight) ・ Fused silica powder (flat (Equivalent particle size 20 μm, specific surface area 40 m ² / eq) ・ Carbon black ・ Carnauba wax ・ Epoxysilane coupling agent ・ 1.8-diazabicyclo (5.4.0) undecene
7 Compound represented by (hereinafter DBU hereinafter) · tetroxide antimony pentoxide antimony formula _{(3) Mg 3.5 Zn 1.0 Al} 2 (OH) 13 CO 3 · 3.5H 2 O (3) · (4 Compound represented by the formula: Mg _4.0 Zn _1.0 Al ₂ (OH) ₁₃ CO ₃ (4) Compound represented by the formula (5) Mg _4.5 Al ₂ (OH) ₁₃ CO ₃ .3.5H ₂ O (5)

Example 1 7.0 parts by weight of epoxy resin A 2.6 parts by weight of curing agent D 2.6 parts by weight of curing agent E 1.0 part by weight of brominated epoxy resin F Melted silica powder 82.8 parts by weight ・ Carbon black 0.2 parts by weight ・ Carnauba wax 0.3 parts by weight ・ Epoxysilane coupling agent 0.3 parts by weight ・ DBU 0.2 parts by weight ・ Diantimony tetroxide 2.0 parts by weight ・1.0 part by weight of the compound represented by the formula (3) was mixed at room temperature with a mixer, kneaded at 70 to 120 ° C. with a biaxial roll, cooled, and pulverized to obtain a molding material. The obtained molding material was doublet, and a 6 × 6 mm chip was used for a solder crack test at 175 ° C., 70 kg / cm ² and 120 seconds by a low pressure transfer molding machine.
Sealed in pQFP, and 3 × 3.5 for high temperature storage test
mm chips were sealed in 16pDIP. The sealed test elements were subjected to the following solder crack test and high-temperature storage test. For the others, the following evaluation was performed using this molding material.

<< Evaluation Method >> Spiral flow: Measured under the conditions of 175 ° C., 70 kg / cm ² , and 120 seconds using a test mold according to EMMI-I-66. -Glass transition point (Tg): A test piece molded into a size of 4 mm x 5 mm x 15 mm with a molding temperature of 175 ° C and a curing time of 120 seconds, and post-cured at 175 ° C for 8 hours is a thermomechanical analyzer [Seiko Electronic Industry Co., Ltd., TM
A100], from the measurement chart when measured at a measurement temperature range of 0 to 320 ° C. and a heating rate of 5 ° C./min, α ₁ ,
to determine the α ₂ to the intersection of the extension line. -Solder crack test: 85 sealed test elements
72 hours and 168 hours in an environment of 85 ° C. and a relative humidity of 85%, and then immersed in a solder bath at 260 ° C. for 10 seconds, and observed external cracks with a microscope.・ High temperature storage characteristics test: Sealed test element at 185 ° C
And the electric resistance after 1000 hours was measured. An electrical resistance value of 2Ω or more was regarded as defective, and the occurrence rate was evaluated. Curability: Hardness was measured using a Bacoal hardness meter (BACOL # 935) 10 seconds after the mold was released at a mold temperature of 175 ° C., a pressure of 70 kg / cm ² , and a curing time of 120 seconds. -Flame retardancy test: UL-
94 compliant. Table 1 shows the test results.

<< Examples 2 to 9 >> Compounds were formulated according to the formulations shown in Tables 1 and 2, and molding materials were obtained in the same manner as in Example 1. The spiral flow and Tg of this molding material were measured. Further, a sealed molded product for a test was obtained from this molding material, and a test was performed in the same manner as in Example 1 using this molded product. The test results are shown in Tables 1 and 2. << Comparative Examples 1 to 9 >> formulated according to the formulations in Tables 3 and 4,
A molding material was obtained in the same manner as in Example 1. The spiral flow and Tg of this molding material were measured. Further, a sealed molded product for a test was obtained from this molding material, and a test was performed in the same manner as in Example 1 using this molded product. The test results are shown in Tables 3 and 4.

[0019]

[Table 1]

[0020]

[Table 2]

[0021]

[Table 3]

[0022]

[Table 4]

[0023]

The epoxy resin composition of the present invention has remarkably improved resistance to soldering stress during surface mounting of a semiconductor device and has excellent high-temperature storage characteristics.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI C08K 3/26 C08K 3/26 3/36 3/36 5/56 5/56 H01L 23/29 H01L 23/30 R 23/31

Claims (2)

[Claims] An epoxy resin, a phenol resin curing agent,
In the curing accelerator, surface treatment agent, flame retardant, and all epoxy resin compositions, (a) at least one selected from diantimony tetroxide and diantimony pentoxide as a flame retardant aid
0.1 to 5% by weight of a seed, (b) 80 to 95% by weight of amorphous silica as an inorganic filler, and (c) 0.1 to 5% by weight of a compound represented by the following formula (1) An epoxy resin composition comprising: a cured product of the epoxy resin composition having a glass transition temperature of 90 to 150 ° C. by a thermomechanical analyzer. Mg _x Zn _y Al _z (OH) _{2x + 2y + 3z-2m} (CO ₃ ) _m · nH ₂ O (1) [where x, y, z, and m are represented by the following relationships, and n is Indicates 0 or a positive number. 0 <z / (x + y) ≦ 1, 0 <y
/ X ≦ 1, x ≠ 0, y ≠ 0, 0 ≦ m / z <1.5] 2. An epoxy resin, a phenol resin curing agent,
In the curing accelerator, surface treatment agent, flame retardant, and all epoxy resin compositions, (a) at least one selected from diantimony tetroxide and diantimony pentoxide as a flame retardant aid
0.1 to 5% by weight of a seed, (b) 80 to 95% by weight of amorphous silica as an inorganic filler, and (c) 0.1 to 5% by weight of a compound represented by the following formula (1) A semiconductor device characterized by being encapsulated using an epoxy resin composition containing an epoxy resin composition having a glass transition temperature of 90 to 150 ° C by a thermomechanical analyzer of the epoxy resin composition. . Mg _x Zn _y Al _z (OH) _{2x + 2y + 3z-2m} (CO ₃ ) _m · nH ₂ O (1) [where x, y, z, and m are represented by the following relationships, and n is Indicates 0 or a positive number. 0 <z / (x + y) ≦ 1, 0 <y
/ X ≦ 1, x ≠ 0, y ≠ 0, 0 ≦ m / z <1.5]