JP2003064161A - Epoxy resin composition and semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an epoxy resin composition for sealing a semiconductor having excellent characteristics of moisture resistance reliability and high- temperature storability even when an amine compound is mixed. SOLUTION: This epoxy resin composition for sealing the semiconductor comprises (A) an epoxy resin, (B) a phenol resin, (C) a curing accelerator, (D) an inorganic filler, (E) a compound having a dithiocarbonate group and (F) an amine compound. The epoxy resin composition is characterized in that the amount of the compound containing the dithiocarbonate group is 0.01-0.5 wt.% in the whole epoxy resin composition and the amount of the amine compound is <=0.01 wt.%.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art Semiconductor elements such as IC and LSI are mainly sealed with an epoxy resin composition to form a semiconductor device.
In the recent market trend of miniaturization, weight reduction, and high performance of electronic devices, semiconductor devices are highly integrated, and the surface mounting of semiconductor devices is promoted. It is becoming tough. 2. Description of the Related Art In recent years, semiconductor devices have become larger in size with higher integration of integrated circuits, and semiconductor devices have been changed to surface mount types such as TSOP, TQFP, and BGA. Therefore, there are some problems that cannot be solved by conventional epoxy resin compositions. The biggest problem is that the semiconductor device is exposed to a high temperature of 200 ° C. or more in the solder dipping or solder reflow process due to the use of surface mounting, and the stress when the absorbed moisture explosively vaporizes causes the semiconductor device. The cracks occur in the semiconductor element, the lead frame, peeling occurs at the interface between the various plated joints on the inner lead and the cured product of the epoxy resin composition, and the reliability is significantly reduced.
Therefore, solder crack resistance is particularly important.

In particular, the epoxy resin composition used for the surface-mounting type semiconductor device is mixed with a resin component having a low viscosity and highly filled with an inorganic filler to be cured in order to withstand the thermal stress at the time of mounting. A crystalline epoxy resin such as a biphenyl type epoxy resin or a dicyclopentadiene-modified phenol type epoxy which can increase the strength of a product and further reduce the moisture absorption rate, and can obtain higher toughness than the conventional orthocresol novolac type epoxy resin. Resin and the like are being used. However, since the glass transition temperature of the cured product of the epoxy resin composition using these epoxy resins is lower than that of the conventional one, Cl ⁻ , Br ⁻ , Na ⁺ contained in the epoxy resin composition under high temperature or high humidity is used. Corrosion of the semiconductor circuit is apt to proceed due to the influence of ionic impurities such as, and there is a problem in humidity resistance and storage reliability (hereinafter referred to as high-temperature storability) in which the semiconductor device can maintain its function even in a high temperature atmosphere of about 150 ° C. is there.

In order to improve the high temperature storability, materials with reduced ionic impurities in the raw materials are carefully selected and used, or components such as halogens and antimony oxides which corrode gold wire joints are reduced. Although such a method is used, there are problems such as a decrease in flame retardancy and an increase in cost, and it is not fully satisfactory. Further, in order to improve the moisture resistance reliability, generally, an ion trapping agent that ion-exchanges with impurity ions contained in the epoxy resin composition, for example, Mg ₁ Al _0.45 O _{1.6 7} , Zr (HPO ₄ ) ₂ H ₂ O
, Mg _4.3 Al ₂ (OH) _12.6 CO ₃ · _m H ₂ O, BiO (O
H) and the like are used, but these ion scavengers inactivate the impurity ions contained in the epoxy resin composition by ion exchange, and at the same time, counter ions (ion exchange with impurity ions, for example, Since it releases phosphoric acid, nitrate ions, etc.), the pH of the molded article of the epoxy resin composition is changed, and as a result, the moisture resistance reliability is improved, but the high temperature storage property is deteriorated.

In consideration of commercial mass production, the raw materials contained in the preceding product number may be mixed in to produce epoxy resin compositions containing various raw materials on the same production line. In order to prevent these contaminations, thorough cleaning of the production line process and production with co-washing materials are performed to prevent contamination of the previous product number as much as possible, but it is virtually impossible to completely eliminate the contamination.
In particular, when an imidazole which is an amine compound used as a curing accelerator is mixed, a secondary amino group remains in the cured product, so that a problem that moisture resistance, particularly high temperature storability is greatly deteriorated is likely to occur. It is not always sufficiently satisfactory for applications where high temperature and long-term storability are required.

[0006]

The present invention relates to a semiconductor encapsulating epoxy resin composition and a semiconductor device which are excellent in moisture resistance reliability and high temperature storability even when an amine compound is mixed.

[0007]

The present invention provides [1] (A)
An epoxy resin composition containing an epoxy resin, (B) phenol resin, (C) curing accelerator (D) inorganic filler, (E) compound having dithiocarbonate group, and (F) amine compound 0.01 to 0.5% by weight of a compound having a dithiocarbonate group in the product,
An amine compound is 0.01% by weight or less, and an epoxy resin composition for semiconductor encapsulation, [2] A semiconductor element is encapsulated with the epoxy resin composition according to claim 1. And a semiconductor device.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The epoxy resin used in the present invention refers to all monomers, oligomers and polymers having an epoxy group, for example, biphenyl type epoxy resin, stilbene type epoxy resin, hydroquinone type epoxy resin, bisphenol F type epoxy resin. And other crystalline epoxy resin, bisphenol A type epoxy resin, phenol aralkyl type epoxy resin (having a phenylene skeleton, diphenylene skeleton, etc.), orthocresol novolac type epoxy resin, phenol novolac type epoxy resin,
Dicyclopentadiene modified phenolic epoxy resin,
Examples thereof include, but are not limited to, triphenol methane type epoxy resin, alkyl-modified triphenol methane type epoxy resin, triazine nucleus-containing epoxy resin, and naphthol type epoxy resin. These may be used alone or in combination. In particular, a biphenyl type epoxy resin capable of achieving a low viscosity of the epoxy resin composition and a phenol aralkyl type epoxy resin capable of achieving a low moisture absorption (having a phenylene skeleton, a diphenylene skeleton, etc.) are preferable.

The phenol resin used in the present invention refers to all monomers, oligomers and polymers having a phenolic hydroxyl group in the molecule, for example, phenol novolac resin, cresol novolac resin, terpene modified phenol resin, dicyclopentadiene modified phenol. Examples thereof include resins, triphenolmethane type resins, phenol aralkyl resins (having a phenylene skeleton, biphenyl skeleton, etc.), naphthol aralkyl resins (having a phenylene skeleton, biphenyl skeleton, etc.), but are not limited thereto. These may be used alone or in combination. In particular, a phenol aralkyl resin (having a phenylene skeleton, a diphenylene skeleton, etc.) capable of achieving a low viscosity of the epoxy resin composition is preferable. The equivalent ratio of the epoxy groups of all epoxy resins and the phenolic hydroxyl groups of all phenol resins is not particularly limited, but is preferably 0.7 to
1.4, particularly preferably 0.8 to 1.2. 0.7
When it is out of the range of from 1.4 to 1.4, curability, moisture resistance reliability and the like may decrease.

The curing accelerator used in the present invention includes
Any compound that accelerates the crosslinking reaction between the epoxy resin and the phenol resin may be used, and examples thereof include organic phosphorus compounds such as triphenylphosphine and tetraphenylphosphonium / tetraphenylborate salts, but are not limited thereto. Not something. These may be used alone or in combination.

The type of the inorganic filler used in the present invention is not particularly limited, and those generally used as the sealing material can be used. Examples thereof include fused crushed silica, fused spherical silica, crystalline silica, secondary agglomerated silica, alumina, titanium white, and aluminum hydroxide, which may be used alone or in combination. Fused spherical silica is particularly preferable. It is preferable that the shape of the particles is infinitely spherical, and the amount of filling can be increased by mixing particles having different sizes. The content of the inorganic filler is 65 to 65 in the total epoxy resin composition.
It is preferably 94% by weight, more preferably 75 to 91% by weight. If it is less than 65% by weight, the reinforcing effect due to the inorganic filler will not be sufficiently exhibited, and the amount of the resin component, which is a factor of moisture absorption, will increase, so that the amount of moisture absorption of the cured product of the epoxy resin composition will increase and during soldering treatment. There is a possibility that cracks may easily occur in the semiconductor device. When it exceeds 94% by weight, the fluidity of the epoxy resin composition is extremely lowered, and there is a possibility that defective filling, chip shift, pad shift, and wire sweep may occur during molding. The inorganic filler used in the present invention is preferably sufficiently mixed in advance. If necessary, the inorganic filler may be pretreated with a coupling agent, an epoxy resin, a phenol resin or the like, and the treatment method may be, for example, a method of removing the solvent after mixing with a solvent. , A method of directly adding to the inorganic filler and treating with a mixer.

The compound having a dithiocarbonate group used in the present invention contains a functional group represented by the formula (1). For example, an esterified product of methacrylic acid represented by formula (2), a copolymer of methacrylic acid ester represented by formula (3) and methacrylic acid, a copolymer of methacrylic acid ester represented by formula (4) and styrene, etc. There is. These products are commercially available from, for example, Kyowa Hakko Kogyo Co., Ltd.

[0013]

[Chemical 1]

[0014]

[Chemical 2]

[0015]

[Chemical 3]

[0016]

[Chemical 4]

The dithiocarbonate group is particularly characterized in that it reacts with an amine compound as shown in formula (5) to incorporate the amine compound into the molecule and immobilize it. This makes it possible to fix the amine compound contained in the epoxy resin composition and improve the moisture resistance. The compounding amount of the compound having a dithiocarbonate group is essentially 0.01 to 0.5% by weight based on the total epoxy resin composition. 0.0
If it is less than 1% by weight, the amine compound mixed in the epoxy resin composition cannot be completely fixed, and if it exceeds 0.5% by weight, the water absorption of the semiconductor device is increased and the solder crack resistance is deteriorated. It is not preferable because it may occur. Further, the amine compound mixed in the epoxy resin composition is
It is necessary to be 0.01% by weight or less in the total epoxy resin composition. If it exceeds 0.01% by weight, immobilization of the amine compound with the compound having a dithiocarbonate group is insufficient, and the expected improvement in moisture resistance cannot be expected, which is not preferable.

[0018]

[Chemical 5]

The amine compound in the present invention means all amines of primary amine, secondary amine and tertiary amine used as a curing agent or an effect accelerator. Examples of these amine compounds include 2-phenylimidazole derived from a curing accelerator and 1,8-diazabicyclo (5,4,4).
0) Examples include diazabicycloalkene such as undecene-7 and its derivatives, and curing agent-derived 4,4-diaminodiphenylmethane. However, the present invention is not limited thereto.

The epoxy resin composition of the present invention comprises (A)-
In addition to the component (E), colorants such as carbon black and red iron oxide, stress reducing agents such as silicone oil and silicone rubber, natural wax, synthetic wax, higher fatty acids and metal salts thereof, or mold release of paraffins, etc. Various additives such as agents and antioxidants can be added. The epoxy resin composition of the present invention is obtained by mixing the components (A) to (E) using a mixer, melt-kneading them with a kneader such as a hot roll, a heating kneader, an extruder, etc., cooling and pulverizing. It is then usually molded into tablets. In this manufacturing process, various materials remaining in a trace amount during the process, and a kneaded product from the subsequent process may be mixed, and in particular, a semiconductor sealed with an epoxy resin composition obtained by mixing an amine compound A compound having a dithiocarbonate group is used to prevent deterioration of the high temperature storage property of the device. In order to manufacture a semiconductor device by sealing an electronic component such as a semiconductor element using the epoxy resin composition of the present invention, it may be cured and molded by a molding method such as a transfer mold, a compression mold, an injection mold. The epoxy resin composition of the present invention is particularly suitable for thin semiconductor devices such as LQFP and TSOP.

Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. The mixing ratio is parts by weight. Example 1 Orthocresol novolac type epoxy resin (softening point 65 ° C., epoxy equivalent 200) 19.5 parts by weight Phenol novolac resin (softening point 80 ° C., hydroxyl equivalent 104) 12.0 parts by weight Compound 0 shown in Formula (2) 0.05 parts by weight Triphenylphosphine 0.25 parts by weight Spherical fused silica 66.410 parts by weight BiO (OH) 0.2 parts by weight Carnauba wax 0.3 parts by weight Carbon black 0.3 parts by weight using a mixer After mixing, the surface temperature is 9
A kneaded material sheet obtained by kneading 20 times using a biaxial roll at 5 ° C. and 25 ° C. was cooled and then pulverized to obtain an epoxy resin composition. Similarly, according to Table 2, after mixing each component including an amine compound using a mixer, and kneading 20 times using a biaxial roll having a surface temperature of 95 ° C. and 25 ° C., the obtained kneaded product sheet is cooled. The resulting mixture was pulverized and passed through a 100-mesh sieve to obtain an amine compound-containing poxoxy resin composition 1. The epoxy resin composition and the amine compound-containing epoxy resin composition 1 were mixed according to the mixing ratio shown in Table 1 to obtain an epoxy resin composition in which an amine compound was mixed. The evaluation results are shown in Table 1.

Evaluation Method Spiral Flow: Using a spiral flow measuring mold according to EMMI-1-66, the mold temperature was 175 ° C., the injection pressure was 6.9 MPa, and the curing time was 120 seconds. Molded product pH: Mold temperature 175 ° C, injection pressure 8.3MP
a, a molded product molded with a curing time of 180 seconds is post-cured after molding, treated at 175 ° C. for 8 hours, and then crushed to 1
4 g of a sample that passed through a 00 mesh sieve was obtained. Subsequently, 100 g of boiled ion-exchanged water was added, and the supernatant liquid after standing for 24 hours was set to a value measured using a pH meter. Moisture resistance reliability: Using a low-pressure transfer molding machine, mold temperature 175 ° C., injection pressure 8.3 MPa, curing time 120
A 16-pin SOP (thickness 1.95 mm, chip size 3.5 mm × 3.0 mm) was molded in seconds, and post-cured at 175 ° C. for 8 hours. Pressure cooker test of sealed test element (125 ° C, pressure 2.2 × 1
0 ⁵ Pa) performed to measure the open circuit failure, expressed in failure time. The unit is hours. High-temperature storability: 16-pin DIP using a low-pressure transfer molding machine at a mold temperature of 175 ° C and an injection pressure of 8.3 MPa
(Chip size 3 mm x 3.5 mm) was molded. After the post-cure treatment at 175 ° C. for 8 hours, a high temperature storage test (185 ° C., 1000 hours) was performed, and it was determined that the electrical resistance between the wirings increased by 20% with respect to the initial value. A total of 20 wirings of 2 wirings per package and 10 packages were measured, and the number between defective wirings was shown in percentage. Units%.

Examples 2 to 6 and Comparative Examples 1 to 6 In Examples 5 and Comparative Examples 1 and 5, the epoxy resin compositions were obtained in the same manner as in Example 1 according to the formulations shown in Table 1, Table 2 and Table 3. And evaluated in the same manner as in Example 1. The results are shown in Tables 1 and 3.
Shown in. Example 2 Orthocresol novolac type epoxy resin (softening point 65 ° C., epoxy equivalent 200) 19.5 parts by weight Phenol novolac resin (softening point 80 ° C., hydroxyl equivalent 104) 12.0 parts by weight Compound 0 shown in Formula (2) 0.055 parts by weight 1,8-diazabicyclo (5,4,0) undecene-7 0.002 parts by weight triphenylphosphine 0.25 parts by weight spherical fused silica 67.408 parts by weight BiO (OH) 0.2 parts by weight carnauba Wax 0.3 parts by weight Carbon black 0.3 parts by weight was mixed with each component using a mixer, and then the surface temperature was 9
A kneaded material sheet obtained by kneading 20 times using a biaxial roll at 5 ° C. and 25 ° C. was cooled and then pulverized to obtain an epoxy resin composition. The results are shown in Table 1. Other Examples and Comparative Examples were evaluated according to the formulations of Tables 1 and 3 in the same manner as Example 2. The results are shown in Tables 1 and 3. The biphenyl type epoxy resin (YX-4000 manufactured by Japan Epoxy Resin Co., Ltd.) used in Examples 5 and 6 and Comparative Examples 5 and 6 has a melting point of 105.
C., epoxy equivalent 195. The phenol aralkyl resin (XLC-LL manufactured by Mitsui Chemicals, Inc.) used in Examples 5 and 6 and Comparative Examples 5 and 6 has a softening point of 79 ° C. and a hydroxyl equivalent of 174.

[0024]

[Table 1]

[0025]

[Table 2]

[0026]

[Table 3]

[0027]

Industrial Applicability The semiconductor device using the epoxy resin composition for semiconductor encapsulation of the present invention is excellent in moisture resistance reliability and high temperature storability even if an amine compound is mixed, and is industrially useful.

Front page continuation (51) Int.Cl. ⁷ Identification code FI theme code (reference) C08L 63/00 C08L 63/00 Z H01L 23/29 H01L 23/30 R 23/31 F term (reference) 4J002 BG073 CC04X CC05X CC06X CD04W CD05W CD06W CD07W CD13W CE00X DE137 DE147 DJ017 EV318 EW016 EY016 FD017 FD090 FD156 FD160 GQ05 4J036 AA01 AC01 AC02 AD07 AD08 AD10 AE05 AE07 AF06 EA04 EA20 EA20 EA02 EA02 EA03 FB03 GA01 A02 JA02 A01 A02 A01 A01 A02 A01 AC01 A02 A01 CA01 A02 A01 CA01 A02 A01 CA01 A02 A01 A01 A02 A01 CA01 A02 A01 A01 A02 A01 AC01 A02 A01 CA01 A02 A01 CA01 A02 A01 A01 EA02 FB03 GA01 A01 A02 A01 A01 EA02 FB03 GA12 A06 A01 A01 A02 EA02 FB03 GA12 A06 A01 AC01 AC01 AC02 AC01 DC01 DC01

Claims (2)

[Claims] 1. An epoxy resin containing (A) an epoxy resin, (B) a phenol resin, (C) a curing accelerator (D) an inorganic filler, (E) a compound having a dithiocarbonate group and (F) an amine compound. In the composition, the compound having a dithiocarbonate group in the total epoxy resin composition is 0.0
An epoxy resin composition for semiconductor encapsulation, which comprises 1 to 0.5% by weight and an amine compound in an amount of 0.01% by weight or less. 2. A semiconductor device obtained by encapsulating a semiconductor element using the epoxy resin composition according to claim 1.