JPH0827252A - Epoxy resin composition and semiconductor sealing device - Google Patents

Abstract

PURPOSE:To obtain an epony resin composition useful for a semiconductor sealing device, etc., having excellent water vapor resistance, solder heat resistance, moldability and thermal conductivity, comprising a specific epoxy resin, a phenol resin, a prescribed silane coupling agent, silicon nitride powder and a curing promoter. CONSTITUTION:This resin composition comprises (A) a biphenyl type epoxy resin of formula I, (B) a phenol resin [e.g. a compound of formula II ((n) is an integer of 0 or >=1)], (C) a silane coupling agent of formula III (R<1> is an epoxy-containing atomic group; R<2> is methyl or ethyl; (n) is an integer of 0 or >=1) (e.g. a compound of formula IV) to which a very small amount of an organic base is added), (D) silicon nitride powder having <=100mum maximum particle diameter and (E) a curing promoter as essential components and contains 25-90wt.% of the component D based on the whole composition. The component C contains preferably 0.005-0.05wt.% of the added organic base such as dimethylamine.

Description

Detailed Description of the Invention

[0001]

The present invention relates to moisture resistance, solder heat resistance,
The present invention relates to an epoxy resin composition excellent in moldability and thermal conductivity and a semiconductor encapsulation device.

[0002]

2. Description of the Related Art In recent years, in the field of semiconductor integrated circuits,
At the same time as technology development for high integration and high reliability, automation of the mounting process of semiconductor devices is being promoted. For example, when mounting a flat package type semiconductor device on a circuit board, conventionally, soldering is performed for each lead pin, but recently, a solder dipping method or a solder reflow method has been adopted.

[0003]

A conventional semiconductor device, that is, a semiconductor device sealed with a resin composition comprising an epoxy resin such as a novolac type epoxy resin, a novolac type phenolic resin and an inorganic filler is a solder bath for the entire device. There is a drawback in that the moisture resistance is lowered by the immersion. In particular, when a semiconductor device that has absorbed moisture is dipped, peeling between the encapsulating resin and the semiconductor chip, or the encapsulating resin and the lead frame, and internal resin cracking cause significant deterioration in moisture resistance, causing disconnection and moisture due to electrode corrosion. As a result, there is a drawback that a semiconductor device cannot guarantee long-term reliability.

Further, by highly filling the inorganic filler, the proportion of the resin component can be reduced and the moisture absorption of the resin composition can be reduced. However, the fluidity is remarkably increased as the inorganic filler is highly filled. Not only is it damaged, but the interface between the organic components such as the resin and the inorganic filler is increased, so that the internal resin crack propagates through the interface and progresses to the external resin crack.

Further, due to the increase in the amount of heat generated by the semiconductor element due to high integration, a material having a high thermal conductivity is being demanded not only for the package structure but also for the sealing material.
Since silicon nitride powder has higher thermal conductivity than fused silica powder, when it is used as a filler, high thermal conductivity can be expected, but good fluidity cannot be obtained when highly filled. There was a drawback.

The present invention has been made in order to solve the above-mentioned drawbacks and is less affected by moisture absorption, and particularly excellent in moisture resistance after solder bath immersion, solder heat resistance, moldability, fluidity and thermal conductivity. No peeling between the encapsulation resin and the semiconductor chip or the encapsulation resin and the lead frame, no internal resin cracks, no wire breakage due to electrode corrosion, no leakage current due to moisture, and no die wear, and long-term It is intended to provide an epoxy resin composition and a semiconductor encapsulation device that can guarantee reliability.

[0007]

As a result of intensive studies aimed at achieving the above object, the present inventors have found that moisture resistance is improved by using a specific epoxy resin, a specific silane coupling agent and a silicon nitride powder. It was found that a resin composition excellent in heat resistance, solder heat resistance, moldability, and thermal conductivity can be obtained, and the present invention has been completed.

That is, the present invention provides (A) a biphenyl type epoxy resin represented by the following general formula,

[0009]

Embedded image (B) a phenol resin, (C) an silane coupling agent having an epoxy group represented by the following general formula, to which an organic base is added in a very small amount,

[0010]

Embedded image R ¹ —C _n H _2n —Si (OR ² ) ₃ (wherein R ¹ is an atomic group having an epoxy group, R ²
Represents a methyl group or an ethyl group, and n represents an integer of 0 or 1 or more.) (D) A silicon nitride powder having a maximum particle size of 100 μm or less and (E) a curing accelerator are essential components, and the entire resin composition An epoxy resin composition comprising the above-mentioned (D) silicon nitride powder in a proportion of 25 to 90% by weight with respect to the product. A semiconductor encapsulation device is obtained by encapsulating a semiconductor chip with a cured product of this epoxy resin composition.

The present invention will be described in detail below.

As the epoxy resin (A) used in the present invention, the biphenyl type epoxy resin represented by the above general formula 5 is used. In addition, a novolac-based epoxy resin, an epibis-based epoxy resin, and other known epoxy resins can be used in combination with this epoxy resin.

The (B) phenol resin used in the present invention is not particularly limited as long as it has at least two phenolic hydroxyl groups in the molecule capable of reacting with the epoxy groups of the epoxy resin (A). . As a specific compound, for example,

[0014]

[Chemical 7] (However, n represents 0 or an integer of 1 or more)

[0015]

Embedded image (However, n represents 0 or an integer of 1 or more)

[0016]

[Chemical 9] (However, n represents 0 or an integer of 1 or more)

[0017]

[Chemical 10] (However, n represents 0 or an integer of 1 or more)

[0018]

[Chemical 11] (However, n represents 0 or an integer greater than or equal to 1) etc., These can be used individually or in mixture.

As the silane coupling agent having an epoxy group, to which an extremely small amount of the organic base (C) is added, which is used in the present invention, the one represented by the above general formula 6 is used.
As a concrete example, for example,

[0020]

[Chemical 12]

[0021]

[Chemical 13] Etc., and these can be used alone or in combination.

It is important to add a very small amount of organic base to the silane coupling agent. The hydrolyzability can be increased by treating with an organic base.
Examples of the organic base to be added here include cyclic organic bases such as dimethylamine, diethylamine, pyridine, quinoline and piperidine, and these can be used alone or in combination of two or more. The addition amount of the organic base is 0.0005 to the silane coupling agent.
It is desirable to use within the range of 0.05% by weight. If the content is less than 0.0005% by weight, the hydrolysis of the silane coupling agent cannot be sufficiently promoted, and if it exceeds 0.05% by weight, the moisture resistance reliability decreases, which is not preferable.

The (D) silicon nitride powder used in the present invention preferably has a low impurity concentration and a maximum particle size of 100 μm or less. Further, in order to make the filler highly filled, a fused silica powder having a low impurity concentration and a maximum particle size of 100 μm or less can be used together. These fillers are
The average particle size is preferably 30 μm or less. Average particle size is
If it exceeds 30 μm, the moisture resistance and the moldability are deteriorated, which is not preferable. The silicon nitride powder is preferably blended in such an amount that it is contained in an amount of 25 to 90% by weight based on the total resin composition. When the proportion is less than 25% by weight, the hygroscopicity of the resin composition is high and the moisture resistance after solder immersion is poor, and when it exceeds 90% by weight, the fluidity is extremely deteriorated and the moldability is poor, which is not preferable. By adding an organic base to a silane coupling agent to these silicon nitride powders and immediately treating them with a Henschel mixer, a super mixer or the like, the surface can be uniformly treated and the effect can be sufficiently exhibited.

As the curing accelerator (E) used in the present invention, a phosphorus curing accelerator, an imidazole curing accelerator, and D
A wide range of BU-based curing accelerators and other curing accelerators can be used. These can be used alone or in combination of two or more kinds. It is desirable that the curing accelerator is blended in an amount of 0.01 to 5% by weight based on the total resin composition. If the proportion is less than 0.01% by weight, the gel time of the resin composition will be long and the curing characteristics will be poor, and if it exceeds 5% by weight, the fluidity will be extremely poor and the moldability will be poor.
Furthermore, the electrical characteristics are poor and the moisture resistance is poor, which is not preferable.

The epoxy resin composition of the present invention contains the above-mentioned specific epoxy resin, phenol resin, specific silane coupling agent containing a small amount of an organic group, silicon nitride powder and a curing accelerator as essential components. Release agents such as natural waxes, synthetic waxes, metal salts of straight-chain fatty acids, acid amides, esters, paraffins, antimony trioxide, etc., as long as they do not violate the object of the invention and as necessary. The flame retardant, the colorant such as carbon black, the rubber-based or silicone-based low stress imparting agent, and the like can be appropriately added and blended.

The general method for preparing the epoxy resin composition of the present invention as a molding material is as follows: the specific epoxy resin, the phenol resin, the specific silane coupling agent, the silicon nitride powder, the curing accelerator and other components. Can be mixed and sufficiently homogenously mixed with a mixer or the like, and further subjected to melt mixing treatment with a hot roll or mixing treatment with a kneader or the like, and then cooled and solidified to be pulverized to an appropriate size to obtain a molding material. When the molding material thus obtained is applied to sealing, coating, insulation, etc. of electronic parts or electric parts such as semiconductor devices, excellent properties and reliability can be imparted.

The semiconductor encapsulation device of the present invention can be easily manufactured by encapsulating a semiconductor chip using the above molding material. The semiconductor chip to be sealed is not particularly limited to, for example, an integrated circuit, a large scale integrated circuit, a transistor, a thyristor, a diode and the like. The most common method of sealing is a low-pressure transfer molding method, but sealing by injection molding, compression molding, casting or the like is also possible. After sealing with a molding material, it is heated and cured, and finally a semiconductor sealing device sealed with this cured product is obtained. For curing by heating, it is desirable to heat and cure at 175 ° C or higher.

[0028]

The epoxy resin composition and the semiconductor encapsulation device of the present invention are obtained by using a specific epoxy resin, a phenol resin, a specific silane coupling agent containing a trace amount of an organic base, a silicon nitride powder and a curing accelerator. , The effect is obtained. That is, a small amount of organic base accelerates the hydrolysis of the silane coupling agent, enhances the reactivity between organic components such as resin and inorganic components, and uses silicon nitride with a maximum particle size of 100 μm or less and a specific epoxy resin. By the above, high filling can be achieved without impairing fluidity, the interface strength between the organic content and the inorganic content is increased, and the water absorption of the resin composition is reduced
Moldability and fluidity are improved, resin cracks are not generated after solder immersion and solder reflow, good thermal conductivity is exhibited, and moisture resistance deterioration is reduced.

[0029]

EXAMPLES Next, the present invention will be described with reference to examples, but the present invention is not limited to these examples. In the following examples and comparative examples, “%” means “% by weight”.

Example 1 77% of silicon nitride powder (maximum particle size of 100 μm or less) and 10% of fine fused spherical silica powder (average particle size of 0.5 μm) were put into a Henschel mixer, and the silane of the above chemical formula 12 was stirred while stirring. Surface treatment was performed by adding 0.4% of a coupling agent and 4 × 10 ⁻⁴ % of diethylamine.

Next, 5.0% of the biphenyl type epoxy resin of the above chemical formula 5, 1.0% of tetrabromobisphenol A type epoxy resin, and the phenol novolac resin of the above chemical formula 7
1.2%, the above-mentioned phenol aralkyl resin of chemical formula 2.5
%, Triphenylphosphine 0.2%, carnauba wax 0.4%, carbon black 0.3%, antimony trioxide
2.0% was mixed at room temperature, further kneaded and cooled at 90 to 100 ° C., and then pulverized to produce a molding material.

Examples 2 to 3 Molding materials having the compositions shown in Table 1 were produced in the same manner as in Example 1.

Comparative Examples 1 to 3 Molding materials having the compositions shown in Table 1 were produced in the same manner as in Example 1.

Using the molding material thus produced, 170 ° C.
A semiconductor encapsulation device was manufactured by injecting transfer into a heated mold, encapsulating a semiconductor chip and curing it. Various tests were conducted on these semiconductor encapsulation devices, and the results are shown in Table 2. The epoxy resin composition and the semiconductor encapsulation device of the present invention show moisture resistance, solder heat resistance, moldability, and thermal conductivity. The excellent effect of the present invention could be confirmed.

[0035]

[Table 1]

[0036]

[Table 2] * 1: Spiral flow measurement (175 ° C) according to EMMI-I-66. * 2: Higher flow viscosity (175 ° C). * 3: A molded product (test piece) obtained by transfer molding at 175 ° C, 80 kg / cm ² for 2 minutes was prepared, post-cured at 175 ° C for 8 hours, and tested according to JIS-K-6911. . * 4: A molded product similar to * 3 was made, post-cured at 175 ° C for 8 hours, and a test piece of appropriate size was measured using a thermomechanical analyzer. * 5: A molded product with a diameter of 100 mm and a thickness of 25 mm was made and measured using a thermal conductivity meter. * 6: A 5.3 x 5.3 mm chip was placed in a VQFP 80-pin (12 x 12 x 1.4 mm) package mold, transfer molded using the molding material for 2 minutes at 175 ° C, and then post-cured at 175 ° C for 8 hours. It was The semiconductor encapsulation device thus obtained was subjected to moisture absorption treatment at 85 ° C, 85% for 48 hours, and then calculated by the increased weight. * 7: The semiconductor encapsulation device of VQFP80pin package of * 6 was passed through an air reflow machine (Max 240 ° C) and examined for external and internal cracks. * 8: Could not be filled in molding the VQFP 80pin package of * 6.

[0037]

As is clear from the above description and Table 2, the epoxy resin composition and the semiconductor encapsulating device of the present invention are excellent in moisture resistance, solder heat resistance, moldability and thermal conductivity, and are thin. It is excellent in the filling property of the package and so on, is less affected by moisture absorption, has good heat dissipation, and can guarantee reliability for a long period of time.

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Claims (2)

[Claims] 1. (A) a biphenyl type epoxy resin represented by the following general formula: (B) Phenolic resin, (C) Organic base-added silane coupling agent having an epoxy group represented by the following general formula: embedded image R ¹ —C _n H _2n —Si (OR ² ) ₃ (wherein R ¹ is an atomic group having an epoxy group, R ²
Represents a methyl group or an ethyl group, and n represents an integer of 0 or 1 or more.) (D) A silicon nitride powder having a maximum particle size of 100 μm or less and (E) a curing accelerator are essential components, and the entire resin composition An epoxy resin composition comprising 25 to 90% by weight of the silicon nitride powder of (D) with respect to the product. 2. A biphenyl-type epoxy resin represented by the following general formula: A silane coupling agent having an epoxy group represented by the following general formula, wherein (B) a phenol resin and (C) an organic base are added in an extremely small amount: embedded image R ¹ —C _n H _2n —Si (OR ² ) ₃ (wherein R ¹ is an atomic group having an epoxy group, R ²
Represents a methyl group or an ethyl group, and n represents an integer of 0 or 1 or more.) (D) A silicon nitride powder having a maximum particle size of 100 μm or less and (E) a curing accelerator are essential components, and the entire resin composition A semiconductor encapsulation device, wherein a semiconductor chip is encapsulated with a cured product of an epoxy resin composition containing 25 to 90% by weight of the silicon nitride powder of (D) with respect to the product.