JP2005314568A - Epoxy resin composition for semiconductor sealing and semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an epoxy resin composition for semiconductor sealing that has low dielectric constant and excellent moldability. <P>SOLUTION: This epoxy resin composition for semiconductor sealing comprises, as essential components, (A) epoxy resin, (B) phenol resin, (C) hardening accelerator, (D) an inorganic filler including crushed or spherical hexagonal BN as essential components. Preferably, the hexagonal BN is crushed or spherical in the epoxy resin composition for semiconductor sealing. The semiconductor devices are produced by sealing the device with these semiconductor-sealing epoxy resin compositions. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

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

Metal cans, ceramics, epoxy resin compositions, and the like are used for sealing semiconductor elements such as ICs, LSIs, and transistors. Among them, transfer molding of an epoxy resin composition is suitable for low cost and mass production and is widely used. In terms of reliability, improvement of moisture resistance and solder reflow have been achieved by improving epoxy resins and phenolic resins as curing agents.
However, with the recent increase in speed of electronic devices, new measures are required for epoxy resin compositions. In other words, this corresponds to the increase in the frequency handled by the semiconductor device as the speed of electronic equipment increases. The frequency handled by the semiconductor device is increasing year by year. For example, in the information processing field, the operating frequency handled by the CPU has already exceeded 1 GHz and further increased year by year. In the field of information communication, communication using high frequencies at 2.4 GHz, 5 GHz, and several tens of GHz has already been carried out in mobile phones and wireless LANs, and semiconductor devices incorporated therein are required to support high frequencies. ing.

  Various measures have been proposed so far for the problem that the epoxy resin composition used in a semiconductor device handling high frequency has a high dielectric constant. A cyanate resin having a low dielectric constant (see, for example, Patent Document 1 and Patent Document 2), or an epoxy having a low dielectric constant by increasing the OH equivalent and the epoxy equivalent has been proposed (for example, patents). Reference 3). However, since cyanate resin has poor moldability, particularly curability, productivity is significantly reduced. Similarly, even with a resin having a higher hydroxyl equivalent and epoxy equivalent, there is a problem that the moldability is significantly lowered as the equivalent is increased, and sufficient measures have not been taken. Furthermore, the use of hollow inorganic fillers has been proposed as a technique for achieving both releasability and low dielectric constant (see, for example, Patent Document 4). However, since hollow shells cause shell fracture, epoxy using hollow fillers is used. In the resin composition, the dielectric constant increases due to shell destruction during production, and the dielectric constant cannot be sufficiently reduced.

JP-A-6-306168 (pages 2-9) JP 2001-339130 A (pages 2 to 26) JP 2001-72743 A (pages 2 to 9) JP 2001-354754 A (Publication 2-12)

  The present invention has been made to solve the conventional problems as described above, and an object of the present invention is to provide an epoxy resin composition for semiconductor encapsulation having a low dielectric constant and good moldability, and the use thereof. A semiconductor device is provided.

The present invention
[1] An epoxy for semiconductor encapsulation, comprising (A) an epoxy resin, (B) a phenol resin, (C) a curing accelerator, and (D) an inorganic filler containing hexagonal ticker boron as an essential component. Resin composition,
[2] The epoxy resin composition for semiconductor encapsulation according to item [1], wherein the hexagonal ticker boron is crushed or spherical.
[3] The epoxy resin composition for semiconductor encapsulation according to [1] or [2], wherein the cured product of the epoxy resin composition has a dielectric constant of 1.5 or more and 3.0 or less,
[4] A semiconductor device characterized by being sealed using the epoxy resin composition for semiconductor sealing according to any one of [1] or [3],
It is.

  According to the present invention, an epoxy resin composition for semiconductor encapsulation having a low dielectric constant and good moldability can be obtained.

The present invention is an epoxy resin composition comprising an inorganic filler containing an epoxy resin, a phenol resin, a curing accelerator, and a hexagonal ticker boron as an essential component, thereby providing a semiconductor having a low dielectric constant and good moldability. An epoxy resin composition for sealing is obtained. Furthermore, since the dielectric constant of the cured product is as low as 3.0 or less, the characteristics of the element can be sufficiently exhibited in a device that handles a high frequency of 1 GHz or more.
Hereinafter, the present invention will be described in detail.

Epoxy resins used in the present invention are monomers, oligomers, and polymers in general having two or more epoxy groups in one molecule, and the 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 resin, phenol aralkyl type epoxy resin (having a phenylene skeleton, a biphenylene skeleton, or the like) can be used.
These epoxy resins may be used alone or in combination of two or more.

  The phenol 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 novolac resin, cresol novolak resin, dicyclopentadiene modified phenol resin, terpene modified phenol resin, triphenolmethane type resin, phenol aralkyl resin (having phenylene skeleton, biphenylene skeleton, etc.) and the like can be mentioned. A mixture may be used.

  The content of the epoxy resin and the phenol resin is preferably such that the ratio of the number of epoxy groups in the total epoxy resin and the number of phenolic hydroxyl groups in the total phenol resin is 0.8 to 1.3. There is a possibility that the curability of the product is lowered, the glass transition temperature of the cured product is lowered, and the moisture resistance reliability is lowered.

  As a hardening accelerator used for this invention, what is necessary is just to accelerate | stimulate the hardening reaction of an epoxy group and a phenolic hydroxyl group, and what is generally used for a sealing material can be used. For example, diazabicycloalkenes such as 1,8-diazabicyclo (5,4,0) undecene-7 and derivatives thereof, organic phosphines such as triphenylphosphine, imidazole compounds such as 2-methylimidazole, tetraphenylphosphonium tetra Examples thereof include tetra-substituted phosphonium / tetra-substituted borates such as phenyl borate, and triphenylphosphine adducted with benzoquinone, and these may be used alone or in combination.

  As the inorganic filler used in the present invention, crushed and spherical hexagonal ticker boron is used as an essential component. In general, crushed or spherical silica is used for a resin composition used for sealing an electronic component such as an IC. On the other hand, hexagonal ticker boron usually takes a scaly shape due to its crystallinity, but in the scaly state, the content in the resin composition cannot be increased, and a sufficient effect of reducing the dielectric cannot be obtained. The crushed or spherical hexagonal ticker boron can be obtained by forming a flaky powder into a crushed or spherical shape, followed by heating and thermal spraying, but the production method is not limited thereto. The content of hexagonal ticker boron is 35 to 90% by weight, preferably 60 to 90% by weight or more based on the resin composition. If the content of hexagonal ticker boron is less than the lower limit, a sufficient effect of lowering the dielectric can be obtained. If the content exceeds the upper limit, the fluidity is greatly lowered and a problem occurs in moldability. Hexagonal ticker boron may be surface-treated with a silane coupling agent or the like. As a method for the surface treatment, a single treated product may be used or it may be treated at the time of mixing with other compounding raw materials.

  Further, other types of inorganic fillers may be used in combination with hexagonal ticker boron. As the inorganic filler to be used in combination, those which are generally used in epoxy resin compositions for semiconductor encapsulation can be used as long as there is no significant increase in dielectric constant. For example, spherical fused silica, crushed fused silica, crystalline silica, talc, alumina, silicon nitride and the like can be mentioned, and most preferably used are spherical fused silica and crushed fused silica having a low dielectric constant. These inorganic fillers may be used alone or in combination. Moreover, these may be surface-treated with a coupling agent.

The epoxy resin composition of the present invention comprises an inorganic filler containing an epoxy resin, a phenol curing agent, a curing accelerator and hexagonal ticker boron, but in addition to this, a colorant such as carbon black, a natural wax, and the like. Various additives such as a release agent such as synthetic wax, a low stress additive such as rubber, a flame retardant such as brominated epoxy resin, antimony trioxide, and aluminum hydroxide may be appropriately blended.
In the present invention, the dielectric constant of the cured product is 1.5 or more and 3.0 or less, preferably 1.9 or more and 2.5 or less, in order to bring out the characteristics of the high frequency device sufficiently. When 3.0 is exceeded, the noise reduction effect is not sufficient for most devices, and when 3.0 to 2.5, a sufficient effect is exhibited only for some devices.

In addition, the epoxy resin composition of the present invention is sufficiently homogeneously mixed using a mixer or the like, and then melt-kneaded with a kneader such as a hot roll or a kneader, cooled and pulverized to form a powder. Furthermore, the obtained powder is pressurized and tableted.
The epoxy resin composition of the present invention is used to encapsulate various electronic components such as semiconductor elements, and to manufacture semiconductor devices by conventional molding methods such as transfer molding, compression molding, and injection molding. do it.

Examples of the present invention are shown below, but the present invention is not limited thereto. The blending ratio is parts by weight.
Example 1
Cresol novolac epoxy resin [epoxy equivalent 200 g / eq, softening point 75 ° C.]
41.5 parts by weight Phenol novolac resin A [hydroxyl equivalent: 104 g / eq, softening point: 120 ° C.]
21.6 parts by weight 2-methylimidazole (hereinafter referred to as 2Mz) 0.4 parts by weight Crushed hexagonal ticker boron [average particle size 35 μm, maximum particle size 212 μm]
35.0 parts by weight Silane coupling agent (γ-glycidyltrimethoxysilane) 0.4 part by weight Carnauba wax 0.8 part by weight Carbon black 0.3 part by weight was mixed with a mixer, and then using a hot roll. The mixture was kneaded at 95 ° C. for 8 minutes, cooled and pulverized to obtain an epoxy resin composition. The obtained epoxy resin composition was evaluated by the following methods. The results are shown in Table 1.

Evaluation method Spiral flow: Using a mold for spiral flow measurement according to EMMI-1-66, measurement was performed at a mold temperature of 175 ° C., a pressure of 6.9 MPa, and a curing time of 120 seconds. The unit is cm.
Dielectric constant: Using a low-pressure transfer molding machine, a test piece of 50φ-3 mm was molded at a molding temperature of 175 ° C., a pressure of 9.8 MPa, and a curing time of 180 seconds. The test piece was post-cured at 175 ° C./4 hr, and the dielectric constant was measured with a Q meter model 4342A manufactured by Yokogawa Hewlett-Packard Co., Ltd. The measurement frequency is 1 MHz.

Examples 2-8, Comparative Example 1
According to the composition of Table 1, an epoxy resin composition was obtained in the same manner as in Example 1 and evaluated in the same manner as in Example 1. The results are shown in Table 1.
The components used in other than Example 1 are shown below.
Biphenyl epoxy resin [epoxy equivalent 195 g / eq, melting point 105 ° C.]
Bisphenol A type epoxy resin [epoxy equivalent 195 g / eq, melting point 72 ° C.]
Phenol novolac resin B [hydroxyl equivalent 105 g / eq, softening point 80 ° C.]
Phenol novolac resin C [hydroxyl equivalent 105 g / eq, softening point 63 ° C.]
Triphenylphosphine (hereinafter referred to as TPP)
Spherical hexagonal ticker boron [average particle size 25 μm, maximum particle size 74 μm]
Fused spherical silica (average particle size 23μm)

  According to the present invention, an epoxy resin composition for semiconductor encapsulation having a low dielectric constant and good moldability can be obtained, which is suitable for a device that handles a high frequency of 1 GHz or more.

Claims (4)

(A) Epoxy resin, (B) Phenolic resin, (C) Curing accelerator, and (D) An inorganic filler containing hexagonal ticker boron as an essential component, and an epoxy resin composition for semiconductor encapsulation . The epoxy resin composition for semiconductor encapsulation according to claim 1, wherein the hexagonal ticker boron is crushed or spherical. The epoxy resin composition for semiconductor encapsulation according to claim 1 or 2, wherein the cured product of the epoxy resin composition has a dielectric constant of 1.5 or more and 3.0 or less. 4. A semiconductor device, wherein the semiconductor device is sealed using the epoxy resin composition for semiconductor sealing according to claim 1.