JP2003138097A - Epoxy resin composition for semiconductor encapsulation, and semiconductor device using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor-encapsulating epoxy resin composition which can give a cured material excellent in flame retardancy and reliability, furthermore can give high grade flame retardancy though this epoxy resin composition contains neither a bromine compound such as a brominated epoxy resin or the like nor an antimony compound such as antimony trioxide or the like, consequently which has no bad influence on the human body and the environment, and to provide a semiconductor device which is encapsulated with the cured material of this semiconductor-encapsulating epoxy resin composition and has high grade flame retardancy and excellent reliability and also special usefulness in the industry. SOLUTION: The semiconductor-encapsulating epoxy resin composition comprises the essential components of (A) an epoxy resin, (B) a curing agent, (C) a polycarbonate and (D) an inorganic filler. The semiconductor device is encapsulated with the cured material of the above epoxy resin composition.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention provides a cured product which is excellent in high-temperature storage property, flame retardancy and heat resistance and does not contain a bromine compound such as brominated epoxy resin or an antimony compound such as antimony trioxide. The present invention relates to a semiconductor encapsulating epoxy resin composition, and a semiconductor device encapsulated with a cured product of the resin composition.

[0002]

2. Description of the Related Art Currently,
The mainstream semiconductor devices are resin-sealed diodes, transistors, ICs, LSIs, and VLSIs. Generally, epoxy resin has better moldability than other thermosetting resins.
Because of its excellent adhesiveness, electrical characteristics, mechanical characteristics, moisture resistance, etc., semiconductor devices are often sealed with epoxy resin compositions. And in the epoxy resin composition,
A brominated epoxy resin and antimony trioxide are generally blended in order to achieve the flame retardancy standard UL-0 V-0. The combination of the brominated epoxy resin and antimony trioxide has a large radical trapping and air blocking effect in the gas phase, and as a result, a high flame retardant effect is obtained.

However, the brominated epoxy resin has a problem that it emits a toxic gas when it is burned, and antimony trioxide also has powder toxicity. Therefore, considering the effects on the human body and the environment, these flame retardants are used as resins. It is preferred to not include it at all in the composition.

In response to such demands, A has been used as a substitute for brominated epoxy resin or antimony trioxide.
Studies have been conducted on hydroxides such as 1 (OH) ₃ and Mg (OH) ₂ and phosphorus-based flame retardants such as red phosphorus and phosphoric acid ester. However, no matter which compound is used, there are problems such as poor curability during molding and poor moisture resistance, and none of them satisfy the reliability of the semiconductor device, leading to practical application. The current situation is not.

The present invention has been made in view of the above circumstances, and provides a cured product which does not contain a bromine compound such as a brominated epoxy resin and an antimony compound such as antimony trioxide and is excellent in flame retardancy and reliability. It is an object of the present invention to provide an epoxy resin composition for semiconductor encapsulation, and a semiconductor device encapsulated with a cured product of the resin composition.

[0006]

Means for Solving the Problems and Modes for Carrying Out the Invention As a result of intensive studies for achieving the above-mentioned object, the present inventors have found that a semiconductor encapsulation containing an epoxy resin, a curing agent, and an inorganic filler. For epoxy resin composition, by blending a polycarbonate, even without blending a bromine compound such as a brominated epoxy resin and an antimony compound such as antimony trioxide, a cured product having excellent flame retardancy and reliability is obtained, It was found that the semiconductor device sealed with the epoxy resin composition has high heat resistance and high reliability,
The present invention has been completed.

Therefore, the present invention provides an epoxy resin composition for semiconductor encapsulation, which comprises (A) epoxy resin (B) curing agent (C) polycarbonate (D) inorganic filler as an essential component, and Provided is a semiconductor device sealed with a cured product of an epoxy resin composition.

The present invention will be described in more detail below.
The semiconductor encapsulating epoxy resin composition of the present invention contains an epoxy resin, a curing agent that reacts with the epoxy resin to form a crosslinked chain, a polycarbonate, and an inorganic filler.

The (A) epoxy resin used in the present invention has at least two epoxy groups in one molecule and can be cured by various curing agents described later, so long as its molecular structure, molecular weight, etc. There is no limitation on the type, and various epoxy resins known so far can be appropriately selected and used. As a general epoxy resin used, phenol novolac type epoxy resin, novolac type epoxy resin such as cresol novolac type epoxy resin, triphenol methane type epoxy resin, triphenol alkane type epoxy resin such as triphenol propane type epoxy resin and The polymer, biphenyl skeleton-containing epoxy resin, naphthalene skeleton-containing epoxy resin,
Dicyclopentadiene-phenol novolac type epoxy resin, phenol aralkyl type epoxy resin, bisphenol F type epoxy resin, bisphenol A type epoxy resin and other bisphenol type epoxy resin, glycidyl ester type epoxy resin, alicyclic epoxy resin, heterocyclic epoxy Examples thereof include resins, and of these, one kind can be used alone or two or more kinds can be used in combination.

The above epoxy resin has a hydrolyzable chlorine content of 1,000 ppm or less, particularly 500 ppm or less,
It is desirable that the content of each of sodium and potassium be 10 ppm or less. Hydrolyzable chlorine is 100
Exceeding 0ppm, sodium or potassium 10p
If it exceeds pm, the moisture resistance may deteriorate if the semiconductor device is left under high temperature and high humidity for a long time.

As the curing agent (B) used in the present invention, phenol compounds, amine compounds, acid anhydrides and the like which have been conventionally used as curing agents for epoxy resins are generally applicable and are not particularly limited. However, a phenol resin having two or more phenolic hydroxyl groups in one molecule can be preferably used. Specifically, phenol novolac resins, novolac type phenol resins such as cresol novolac resins, resol type phenol resins, phenol aralkyl resins, triphenol methane type resins, triphenol alkane type phenol resins such as triphenol propane type resins and their polymerization. Compounds, naphthalene ring-containing phenol resins, dicyclopentadiene modified phenol resins, bisphenol F type resins, bisphenol A type resins and other bisphenol type phenol resins, and the like, and one of these may be used alone or two or more of them may be used in combination. be able to.

As with the epoxy resin, it is preferable that the content of sodium and potassium of the above curing agent is 10 ppm or less. 1 for sodium or potassium
If it exceeds 0 ppm, the humidity resistance may deteriorate when the semiconductor device is left under high temperature and high humidity for a long time.

Here, the blending amounts of the epoxy resin and the curing agent are not particularly limited, but the curing agent amount is a curing effective amount of the epoxy resin, and when the above-mentioned phenol resin is used, it is contained in the epoxy resin. The molar ratio of the phenolic hydroxyl group contained in the phenolic resin to 1 mol of the epoxy group is preferably 0.5 to 2.0, particularly preferably 0.7 to 1.5.

The (C) polycarbonate used in the present invention is preferably an aromatic polycarbonate having an aromatic ring, more preferably a weight average molecular weight of 6,000 to 5.
Those of 10,000, especially 15,000 to 35,000 are desirable. Specifically, one represented by the following formula (1) can be used.

[Chemical 1] [In the formula, X is a divalent organic group having an aromatic ring such as a benzene ring or naphthalene ring, Z is a monovalent organic group having an aromatic ring such as a benzene ring or naphthalene ring, and n is 1 to 200,
Particularly, it is an integer of 60 to 120. ]

In this case, the following can be exemplified as X, and it can be one kind or a combination of two or more kinds, but it is not limited thereto.

[Chemical 2] [In the formula, R ^{1 to} R ¹⁰ are each independently a monovalent hydrocarbon group which may contain a hydrogen atom or an oxygen atom having 1 to 20 carbon atoms, and the monovalent hydrocarbon group has 1 carbon atom (s). ˜5 alkyl group, C 6-20 aryl group, C 2 ˜
Examples thereof include an alkenyl group having 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, and an aralkyl group having 7 to 17 carbon atoms. Also,
Y is

[Chemical 3] (In the formula, R ^{11 to} R ¹⁸ are each independently a monovalent hydrocarbon group which may contain a hydrogen atom or an oxygen atom having 1 to 20 carbon atoms, and the monovalent hydrocarbon group may have 1 to 1 carbon atoms. 5 alkyl group, C6-20 aryl group, C2-5
And an alkenyl group having 1 to 5 carbon atoms or an aralkyl group having 7 to 17 carbon atoms. m and p are integers of 1 to 20, and q is an integer of 1 to 100. ) Is a group selected from. ]

On the other hand, the following can be exemplified as Z, but it is not limited thereto.

[0017]

[Chemical 4] (In the formula, Y and R ^{1 to} R ¹⁰ are the same as above.)

The reason why the epoxy resin composition of the present invention exhibits good flame retardancy is not clear, but the compound having a repeating structure represented by the above formula (1) has a structure that easily stabilizes electrons by resonance. It is considered to have the effect of suppressing active radicals generated during combustion.

The polymerization degree of the polycarbonate in the present invention is preferably 1 to 200. If the degree of polymerization is too low, sufficient flame retardancy and heat resistance may not be obtained, and if it is too high, flame retardancy and heat resistance are excellent, but the viscosity may increase and melt kneading may be difficult. is there. In order to satisfy various characteristics, it is more preferably 60 to 120. In addition, polycarbonate can be used individually or in combination of 2 or more types.

The addition amount of the above-mentioned (C) polycarbonate is
Although not particularly limited, it is 2 to 100% by weight of the total amount of the epoxy resin, the curing agent, and the polycarbonate.
It is preferably 20% by weight, particularly 2 to 10% by weight. If the addition amount is less than 2% by weight, the flame retardancy and heat resistance may not be effective, and if the addition amount exceeds 20% by weight, the fluidity may decrease.

Since polycarbonate has a high melting point (softening point), it is desirable to make it compatible with an epoxy resin or a curing agent in advance. Means for making them compatible include heating and melting mixing, mixing in a solvent, and the like.

As the inorganic filler (D) of the present invention, those usually blended with the epoxy resin composition can be used. Examples of the inorganic filler include fused silica, silicas such as crystalline silica, alumina, silicon nitride,
Aluminum nitride, boron nitride, titanium oxide,
Glass fiber etc. are mentioned. The average particle diameter and shape of these inorganic fillers are not particularly limited, but spherical fused silica having an average particle diameter of 5 to 40 μm is particularly preferable in terms of moldability and fluidity. In the present invention, the average particle diameter can be obtained as a weight average value (or median diameter) by a laser light diffraction method or the like.

The addition amount of the inorganic filler used in the present invention is
Epoxy resin, hardener and polycarbonate total 100
It is preferably 200 to 1,200 parts by weight with respect to parts by weight. If the addition amount is less than 200 parts by weight, the expansion coefficient increases, the stress applied to the semiconductor element increases, which may lead to deterioration of element characteristics, and the amount of resin with respect to the entire composition increases. The desired flame retardancy may not be obtained. On the other hand, if the addition amount exceeds 1,200 parts by weight, the viscosity at the time of molding becomes high and the moldability may deteriorate. Particularly preferably, it is 600 to 1,000 parts by weight.

The inorganic filler is preferably surface-treated in advance with a coupling agent such as a silane coupling agent or a titanate coupling agent in order to increase the bonding strength between the resin and the inorganic filler. Examples of such coupling agents include γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, and other epoxysilanes, N -Β (aminoethyl) -γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane and other aminosilanes, γ-mercaptotrimethoxysilane and other mercaptosilanes and the like It is preferable to use a silane coupling agent. Here, the amount of the coupling agent used for the surface treatment and the surface treatment method are not particularly limited.

In the present invention, it is preferable to use a curing accelerator in order to accelerate the curing reaction between the epoxy resin and the curing agent. The curing accelerator is not particularly limited as long as it accelerates the curing reaction, and examples thereof include triphenylphosphine, tributylphosphine, tri (p-methylphenyl) phosphine, tri (nonylphenyl) phosphine, triphenylphosphine / triphenylphosphine. Phosphorus compounds such as phenylborate, tetraphenylphosphine / tetraphenylborate, triethylamine, benzyldimethylamine, α-methylbenzyldimethylamine,
1,8-diazabicyclo (5.4.0) undecene-7
A tertiary amine compound such as 2-methylimidazole,
Imidazole compounds such as 2-phenylimidazole and 2-phenyl-4-methylimidazole can be used.

The compounding amount of the curing accelerator is an effective amount, but the total amount of the above epoxy resin, curing agent and polycarbonate is 10
It is preferably 0.1 to 5 parts by weight, especially 0.5 to 2 parts by weight, based on 0 parts by weight.

The epoxy resin composition for semiconductor encapsulation of the present invention may further contain various additives if necessary. For example, thermoplastic resins, thermoplastic elastomers, organic synthetic rubbers, low stress agents such as silicones, waxes such as carnauba wax, higher fatty acids and synthetic waxes, colorants such as carbon black, and additives such as halogen trap agents. It may be added and blended within a range that does not impair the object of the present invention.

The epoxy resin composition for semiconductor encapsulation of the present invention contains, for example, an epoxy resin, a curing agent, a polycarbonate, an inorganic filler, and other additives in a predetermined composition ratio, and the mixture is sufficiently mixed with a mixer or the like. After uniformly mixing, a melt mixing process using a hot roll, a kneader, an extruder or the like is performed, followed by cooling and solidification, and crushing to an appropriate size to obtain a molding material.

The epoxy resin composition for semiconductor encapsulation of the present invention thus obtained can be effectively utilized for encapsulation of various semiconductor devices. In this case, the most general encapsulation method is as follows. A low pressure transfer molding method can be mentioned. The molding conditions for the epoxy resin composition for semiconductor encapsulation of the present invention are as follows: a temperature of 150 to 180 ° C. for 30 to 180 seconds,
Post-curing is preferably performed at a temperature of 150 to 180 ° C. for 2 to 16 hours.

In the present invention, the type of semiconductor device is not particularly limited, and the present invention can be applied to any semiconductor device which has been conventionally sealed with a cured product of an epoxy resin composition for semiconductor sealing. , DIP type, SO type, PLCC
Examples include various semiconductor packages such as molds and flat pack types.

[0031]

INDUSTRIAL APPLICABILITY The semiconductor encapsulating epoxy resin composition of the present invention is capable of obtaining a cured product having excellent flame retardancy and reliability, and moreover, a brominated compound such as brominated epoxy resin Even if an antimony compound such as antimony oxide is not contained in the epoxy resin composition, high flame retardancy can be imparted, so that it has no adverse effect on the human body and the environment. Further, the semiconductor device encapsulated with the cured product of the epoxy resin composition for semiconductor encapsulation of the present invention is imparted with high flame retardancy and excellent in reliability, and is particularly useful industrially.

[0032]

EXAMPLES The present invention will be specifically described below with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples.

[Examples 1 to 6 and Comparative Examples 1 to 4] The components shown in Table 1 were uniformly melt-mixed with a hot double roll, cooled and pulverized to obtain an epoxy resin composition for semiconductor encapsulation. . The following properties (i) to (vii) of these compositions were measured. The results are shown in Table 2.

(I) Spiral flow value Using a mold conforming to the EMMI standard, the temperature is 175 ° C.
The measurement was performed under the conditions of a molding pressure of 6.9 N / mm ² and a molding time of 120 seconds.

(Ii) Gelation time The gel time of the composition was measured on a 175 ° C. hot plate.

(Iii) High temperature electrical resistance temperature 175 ° C., molding pressure 6.9 N / mm ² , molding time 1
Mold a 70φ × 3mm disc under the condition of 20 seconds and
Post cure at 4 ° C for 4 hours. Then, the volume resistivity was measured in an atmosphere of 150 ° C.

(Iv) Flame retardance Based on the UL-94 standard, a plate having a thickness of 1/8 inch was molded at a temperature of 175 ° C., a molding pressure of 6.9 N / mm ² , and a molding time of 120.
The flame-retardant property of the molded product in seconds and post-curing at 180 ° C. for 4 hours was examined.

(V) A moisture-resistant aluminum wiring-formed 6 × 6 mm silicon chip is bonded to a 14 pin-DIP frame (42 alloy), and the aluminum electrode on the chip surface and the lead frame are 30 μmφ gold wire. After wire-bonding with the epoxy resin composition,
Molding was carried out under conditions of molding pressure of 6.9 N / mm ² and molding time of 120 seconds, and post-cured at 180 ° C. for 4 hours. Twenty of these packages were each left in a 121 ° C./100% RH atmosphere for 20 hours under a DC bias voltage of 20 V, and then the number of packages in which aluminum corrosion occurred was examined.

(Vi) High temperature storage reliability A 6 × 6 mm silicon chip with aluminum wiring formed thereon was adhered to a 14 pin-DIP frame (42 alloy), and the aluminum electrode on the chip surface and the lead frame were 30 μmφ. After wire-bonding with a gold wire, the epoxy resin composition is applied thereto at a temperature of 175 ° C.
Molding was carried out under conditions of molding pressure of 6.9 N / mm ² and molding time of 120 seconds, and post-cured at 180 ° C. for 4 hours. After leaving 20 of each of these packages in an atmosphere of 200 ° C. for 500 hours, they were dissolved in fuming nitric acid and opened, and the tensile strength of the gold wire was measured. When the tensile strength was 70% or less of the initial value, it was regarded as a defect, and the number of defects was examined.

(Vii) Heat resistance (oxygen absorption) Temperature 175 ° C., molding pressure 6.9 N / mm ² , molding time 1
Mold a 10 x 4 x 100 mm bar under the condition of 20 seconds,
Post cure was performed at 180 ° C. for 4 hours. Then 200
It was left to stand in an oxygen atmosphere at 0 ° C. for 500 hours, and the oxygen absorption amount was examined.

[0041]

[Table 1]

Epoxy resin (a) o-cresol novolac type epoxy resin: EO
CN1020-55 (Nippon Kayaku, epoxy equivalent 20
0) (b) Biphenyl type epoxy resin: YX-4000HK
(Oilized shell, epoxy equivalent 190) Curing agent (c) Phenol novolac resin: DL-92 (Maywa Kasei, phenolic hydroxyl equivalent 110) (d) Phenol aralkyl type resin: MEH-7800
SS (manufactured by Meiwa Kasei Co., Ltd., phenolic hydroxyl equivalent 175) Polycarbonate (e) Polycarbonate weight average molecular weight represented by the following formula (n = 60) 18,000 (f) Polycarbonate weight average molecular weight represented by the following formula (n = 110) 34,000 (g) Polycarbonate represented by the following formula (n = 210) Weight average molecular weight 62,000

[Chemical 5] Sekirin: Nova Excel 140 (manufactured by Rin Kagaku) Inorganic filler: Spherical fused silica (manufactured by Tatsumori, average particle size 20)
μm) Curing catalyst: Triphenylphosphine (manufactured by Kitako Chemical) Release agent: Carnauba wax (manufactured by Nikko Fine Products) Carbon black: Denka black (manufactured by Denki Kagaku) Silane coupling agent: γ-glycidoxypropyltrimethoxysilane , KBM-403 (manufactured by Shin-Etsu Chemical Co., Ltd.)

[0043]

[Table 2]

From the results shown in Table 2, the cured product of the epoxy resin composition containing polycarbonate was excellent in flame retardancy, moisture resistance and high temperature storage reliability. When red phosphorus was used instead of polycarbonate, the flame resistance was excellent, but the moisture resistance was remarkably inferior. Therefore, the epoxy resin composition of the present invention is a flame-retardant, a cured product having excellent moisture resistance reliability is obtained, and moreover, a bromine compound such as a brominated epoxy resin, an antimony compound such as antimony trioxide is used as a resin composition. Since it is not contained in the product, it has no adverse effect on the human body and the environment.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hiroyuki Takenaka             Gunma Prefecture Usui District, Matsuida Town             Shin-Etsu Chemical Co., Ltd. Silicone electronic materials             Inside the technical laboratory (72) Inventor Kazutoshi Tomiyoshi             Gunma Prefecture Usui District, Matsuida Town             Shin-Etsu Chemical Co., Ltd. Silicone electronic materials             Inside the technical laboratory (72) Inventor Taharu Ikeda             Gunma Prefecture Usui District, Matsuida Town             Shin-Etsu Chemical Co., Ltd. Silicone electronic materials             Inside the technical laboratory (72) Inventor Toshio Shiobara             Gunma Prefecture Usui District, Matsuida Town             Shin-Etsu Chemical Co., Ltd. Silicone electronic materials             Inside the technical laboratory F term (reference) 4J002 CC043 CC053 CD00W CE003                       CG00X DE136 DE146 DJ006                       DJ016 DK006 DL006 FA046                       FB086 FB166 FD016 FD143                       GQ05                 4M109 AA01 CA21 EA02 EB03 EB06                       EB07 EB13 EC20

Claims (2)

[Claims] 1. An epoxy resin composition for semiconductor encapsulation, which comprises (A) epoxy resin (B) curing agent (C) polycarbonate (D) inorganic filler as an essential component. 2. A semiconductor device encapsulated with the cured product of the epoxy resin composition according to claim 1.