JPH07228672A - Resin composition for sealing semiconductor and semiconductor device - Google Patents

Abstract

PURPOSE:To obtain the subject composition consisting essentially of an epoxy resin, a curing agent, an inorganic filler and a specific curing catalyst, excellent in storage property and capable of providing a cured product excellent in low water absorption and reflow crack resistance. CONSTITUTION:In this resin composition composed of an epoxy resin (preferably a bisphenol type epoxy resin), a curing agent (e.g. a bisphenol A type resin), an inorganic filler (preferably globular fused silica) and a curing catalyst, an addition reaction product of an organophosphorus compound expressed by the formula [R<1> is an electron donating substituent group] [preferably (p- monoalkoxyphenyl)-phosphine] with a compound having one or more conjugated double bonds in one molecule [preferably methyl-p-benzoquinone or 1,4- naphthoquinone] is used as the curing catalyst.

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, which provides a cured product excellent in preservability, low water absorption and reflow crack resistance.

[0002]

2. Description of the Related Art Currently,
Surface mount packages have become mainstream as semiconductor devices have been mounted at high densities. When mounting these surface mount type packages, processes such as vapor phase reflow, infrared reflow, solder dipping, etc. are adopted, but in these processes, the package temperature is high (215 to 260 ° C.).
Therefore, the package sealed with the conventional sealing resin has a big problem that the resin portion is cracked at the time of mounting and the reliability cannot be guaranteed.

In recent years, thin TSOP (thin
Packages such as small outline package) and TQFP (thin quad flat package) are becoming mainstream, and the demand for encapsulating resin to satisfy the reflow crack resistance is becoming more and more severe.

On the other hand, recently, in connection with the reduction in the thickness of the above-mentioned package, the requirement for the storability of the resin composition has become strict. That is, an epoxy resin composition containing a conventional curing catalyst undergoes a curing reaction at a considerable rate even at room temperature, so even if the epoxy resin composition is stored in a refrigerator until immediately before use, at the time of use. Since the epoxy resin composition is exposed to room temperature, the fluidity is lowered and the viscosity is increased. As a result, when a thin package is sealed with the epoxy resin composition in which such deterioration has progressed, voids are generated and There is a problem that filling or adhesion failure easily occurs.

The present invention has been made in view of the above circumstances and is excellent in preservability, can prevent deterioration of fluidity and increase of viscosity during use as much as possible, and has low water absorption and resistance to reflow cracking. An object is to provide an epoxy resin composition for semiconductor encapsulation that gives an excellent cured product and a semiconductor device encapsulated with the cured product.

[0006]

Means and Actions for Solving the Problems As a result of intensive studies for achieving the above-mentioned object, the present inventor has found that an epoxy resin, a curing agent, an inorganic filler and a curing catalyst are essential components for semiconductor encapsulation. In the epoxy resin composition, by using an addition reaction product of an organic phosphorus compound represented by the following general formula (1) and a compound having one or more conjugated double bonds in one molecule as a curing catalyst, The resin composition is excellent in storage stability, it is possible to prevent a decrease in fluidity or an increase in viscosity during use as much as possible, and it is possible to give a cured product having low water absorption and excellent reflow crack resistance, In particular, the inventors have found that it is effective to use a biphenyl type epoxy resin as the epoxy resin, and have completed the present invention.

[0007]

[Chemical 2] (However, in the formula, R ¹ represents an electron-donating substituent.)

Therefore, the present invention provides an epoxy resin composition for semiconductor encapsulation, which comprises an epoxy resin, a curing agent, an inorganic filler and a curing catalyst as essential components.
Epoxy resin composition for semiconductor encapsulation using an addition reaction product of the organophosphorus compound of the above formula (1) and a compound having one or more conjugated double bonds in one molecule, and a cured product of this composition Provided is a semiconductor device sealed with.

The present invention will be described in more detail below. The epoxy resin which is the first essential component of the epoxy resin composition for semiconductor encapsulation of the present invention includes a biphenyl type epoxy resin, a novolac type epoxy resin, and a polyfunctional epoxy. Resin, alicyclic epoxy resin, heterocyclic epoxy resin,
Examples thereof include bisphenol A type epoxy resin, naphthalene ring-containing epoxy resin, halogenated epoxy resin and the like.
Among these, a biphenyl type epoxy resin is preferable in order to more effectively exert the action of the above addition reaction product as a curing catalyst, and it is preferable to use another epoxy resin in combination with this if necessary.

Examples of such a biphenyl type epoxy resin include those represented by the following general formula (2).

[0011]

[Chemical 3] (However, in the formula, R ² is a hydrogen atom, a halogen atom or an alkyl group having 1 to 5 carbon atoms, and q is an integer of 0 to 5.) Specific examples of the biphenyl type epoxy resin include the following compounds. You can

[0012]

[Chemical 4]

One of these biphenyl type epoxy resins may be used alone or in combination of two or more, but among these, the epoxy resin composition obtained has a low viscosity and the total amount in the epoxy resin composition is low. Chlorine amount is 500
The compound represented by the above formula (2a) is preferable for reducing the amount to be ppm or less.

The epoxy resin curing agent is not particularly limited in molecular structure and molecular weight as long as it is a compound having two or more functional groups capable of reacting with the epoxy resin. For example, bisphenol A-type and F-type phenol resins, phenol novolac resins, triphenol alkane-type phenol resins and polymers thereof, biphenyl-type phenol resins, dicyclopentadiene-phenol novolac resins, phenol aralkyl-type phenol resins, naphthalene ring-containing phenol resins. In addition to phenol resins such as alicyclic phenol resins and heterocyclic phenol resins, amine-based curing agents, acid anhydride-based curing agents, etc. may be mentioned, and one of these may be used alone or two or more thereof may be used in combination. Can be used.

The compounding amount of the curing agent is a curing amount, and for example, the molar ratio of the amount of epoxy groups in the epoxy resin to the phenolic hydroxyl group in the phenol resin is 0.5 to 2, more preferably 0.5 to 2. 1.5, more preferably 0.8 to 1.5
It is preferable to mix them so that

As the inorganic filler to be added to the epoxy resin composition of the present invention, those usually added to the epoxy resin composition can be used. For example, fused silica, silicas such as crystalline silica, alumina, silicon nitride,
Aluminum nitride, boron nitride, titanium oxide,
Examples thereof include glass fibers, and spherical fused silica is preferable.

The average particle size and shape of these inorganic fillers are not particularly limited, but those having an average particle size of 5 to 30 μm are preferable from the viewpoint of moldability and fluidity, and high filling and stress on the chip surface are prevented. In order to reduce the size, a spherical shape is preferably used. The inorganic filler is preferably surface-treated with a silane coupling agent or the like in advance in order to increase the bond strength between the resin and its surface.

The above-mentioned inorganic fillers may be used alone or in combination of two or more, and the blending amount thereof is not particularly limited, but in order to satisfy low water absorption and reflow crack resistance, 600 parts or more, especially 90 parts per 100 parts by weight of epoxy resin and curing agent
It is preferably 0 part or more.

In the present invention, as a curing catalyst for accelerating the curing reaction between the above epoxy resin, particularly a biphenyl type epoxy resin and a curing agent, an organic phosphorus compound represented by the following general formula (1) and one molecule are included. An addition reaction product with a compound having one or more conjugated double bonds is blended.

[0020]

[Chemical 5]

Here, R ¹ is an electron-donating substituent,
As such a substituent, an alkoxy group having 1 to 4 carbon atoms, particularly 1 to 2 carbon atoms, an alkyl group having 1 to 4 carbon atoms, particularly 1 to 2 carbon atoms,
Examples thereof include an amino group and an alkylamino group in which the alkyl group has 1 to 4 carbon atoms, particularly 1 to 2 carbon atoms. In particular,
As the organic phosphorus compound, an electron-donating substituent is introduced into a phenyl group of triphenylphosphine such as tris (alkoxyphenyl) phosphine, tris (alkylphenyl) phosphine, tris (aminophenyl) phosphine, tris (dialkylaminophenyl) phosphine. An organic tertiary phosphorus compound having the above structure can be given. Among these, tris (methoxyphenyl) phosphine,
Tris (ethoxyphenyl) phosphine, tris (n-
Butoxyphenyl) phosphine, etc.
Tris (p) in which one alkoxy group of 4 was introduced at the para position
-Monoalkoxyphenyl) phosphine is particularly preferable because it gives a cured product having low water absorption and particularly excellent reflow crack resistance to the epoxy resin composition.

Examples of the organic compound containing one or more conjugated double bonds in one molecule which undergoes an addition reaction with the above-mentioned organic phosphorus compound include maleic anhydride and quinones. p-benzoquinone, chloro-p-benzoquinone, bromo-p-benzoquinone, methyl-p-benzoquinone, 1,4-naphthoquinone, 9,1
P-quinones such as 0-anthraquinone are preferred, and among these, methyl-p-benzoquinone or 1,4-
Naphthoquinone is particularly preferable because it gives an epoxy resin composition having excellent storage stability.

The method for obtaining the addition reaction product of the organic phosphorus compound represented by the formula (1) and the organic compound having one or more conjugated double bonds in one molecule is not particularly limited, but is generally Can be easily performed by the following method. That is, an organic phosphorus compound is dissolved in a nonpolar organic solvent such as benzene, toluene, hexane, and cyclohexane in a flask, and the organic compound containing one or more conjugated double bonds in one molecule is added to the above organic solvent. When the solution dissolved in is dropped, an addition reaction easily occurs and a precipitate is deposited. The obtained precipitation product is filtered, washed with an organic solvent and then dried under reduced pressure, whereby the addition reaction product of the present invention can be obtained in good yield.

The addition reaction product can be used by mixing it with an epoxy resin or a curing agent in advance and crushing it in order to facilitate dispersion in the epoxy resin composition.

The amount of the above addition reaction product is preferably 0.5 to 10 parts, especially 1 to 5 parts, based on 100 parts of the total of the epoxy resin and the curing agent.

In addition to the above addition reaction product, a curing catalyst such as an imidazole compound, a tertiary amine compound, or a phosphorus compound can be added if necessary.

The composition of the present invention may further contain various other additives, if desired. For example, thermoplastic resins, thermoplastic elastomers, organic synthetic rubbers, low stress agents such as silicones, waxes such as carnauba wax, fatty acids such as stearic acid and metal salts thereof, pigments such as carbon black, cobalt blue and red iron oxide, oxidation. Flame retardants such as antimony and halogen compounds, silane coupling agents such as glycidoxypropyltrimethoxysilane, surface treatment agents such as alkyl titanates, antiaging agents, and additives such as halogen trapping agents may be added. it can.

The epoxy resin composition of the present invention is prepared by uniformly stirring and mixing the predetermined amounts of the above-mentioned components during the production.
A kneader, a heat roll, which has been heated to 70 to 95 ° C in advance,
It can be obtained by a method such as kneading with an extruder or the like, cooling and pulverizing.

The thus obtained epoxy resin composition of the present invention can be effectively used for encapsulating semiconductor devices such as SOP, SOJ, TSOP and TQFP. In this case, molding is conventionally adopted. The epoxy resin composition of the present invention is effective for the low-pressure transfer molding method, although it can be carried out by adopting a method such as transfer molding, injection molding or casting method. The molding temperature of the epoxy resin composition of the present invention is preferably 150 to 180 ° C. for 30 to 180 seconds, and the post cure is preferably 150 to 180 ° C. for 2 to 16 hours.

[0030]

EFFECT OF THE INVENTION The epoxy resin composition of the present invention gives a cured product which has good storage stability and fluidity, excellent moldability, low water absorption and excellent reflow crack resistance. The semiconductor device encapsulated with the cured product of the epoxy resin composition of the present invention has high reliability.

[0031]

EXAMPLES Hereinafter, the present invention will be specifically shown by showing Examples and Comparative Examples, but the present invention is not limited to the following Examples. In the following examples, all parts are parts by weight.

[Examples 1 to 4 and Comparative Examples 1 to 3] The components shown below and the addition reaction products (curing catalysts) shown in Table 1 were treated with heat 2
This roll was uniformly melt mixed, cooled and pulverized to obtain an epoxy resin composition for semiconductor encapsulation.

Blending composition Blending number Biphenyl type epoxy resin (Note 1) 54.0 Curing agent (Note 2) 29.9 Brominated epoxy resin 8.6 Fused silica 900.0 Antimony trioxide 8.0 Carbon black 2.0 Silane coupling agent 2.5 Release agent 1.5

[0034]

[Chemical 6]

Next, regarding these compositions, the following (a)
Various tests of (b) were conducted. The results are also shown in Table 1. (A) Spiral flow value 175 ° C, 70k using a mold conforming to EMMI standard
It was measured under the conditions of g / cm ² and molding time of 120 seconds. (B) Storage stability The number of days when the spiral flow value reached 80% of each initial value when each resin composition was left in a constant temperature bath at 25 ° C was shown. (C) Gelation time The gelation time of the composition was measured on a hot plate at 175 ° C. (D) Melt viscosity 175 using a high-lower flow tester (manufactured by Shimadzu Corporation)
It was measured at ° C. (E) Molding hardness 175 ° C, 70 kg / cm according to JIS-K6911
^2. The hot hardness when a 10 × 4 × 100 mm bar was molded under the condition that the molding time was 90 seconds was measured with a Barcol hardness meter. (F) Mechanical strength (bending strength and bending elastic modulus) 175 ° C., 70 kg / cm according to JIS-K6911
^2. Bending test pieces of 10 × 4 × 100 mm were molded under the condition of molding time of 120 seconds and post-cured at 180 ° C. for 4 hours, and measured at room temperature. (G) Water absorption of 175 ° C., 70 kg / cm ² , molding time of 120 seconds, and a disk having a diameter of 50 mm and a thickness of 3 mm was molded at 180 ° C.
Post-cured for 4 hours at 85 ℃ / 85% RH
The sample was allowed to stand for 48 hours in a thermo-hygrostat, and the water absorption was measured. (H) Reflow crack A flat package of 14 × 20 × 2.1 mm was molded under the conditions of 175 ° C., 70 kg / cm ² , and a molding time of 120 seconds, and post-cured at 180 ° C. for 4 hours to 85 ° C.
After leaving it in a thermo-hygrostat of / 85% RH for 72 hours to absorb moisture, it was immersed in a solder bath at a temperature of 240 ° C. for 30 seconds, and cracks outside the package were observed.

[0036]

[Table 1]

From the results shown in Table 1, when the curing catalyst is the organic phosphorus compound alone (Comparative Example 1), the storage stability is poor, the fluidity is poor, the melt viscosity is high, and the phenyl group has no substituent ( Comparative Example 2) has poor storage stability, poor fluidity, high melt viscosity, poor physical properties of the cured product, and the phenyl group has no electron donating property (Comparative Example 3). Although the storage stability is good, the reflow crack resistance is inferior.

On the other hand, the epoxy resin compositions containing the curing catalyst according to the present invention (Examples 1 to 4) have good storage stability, good flowability, low melt viscosity, and cured products. It is recognized that the physical properties are good and the reflow crack resistance is good.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshio Shiobara 1-1 Otomi, Matsuida-cho, Usui-gun, Gunma Prefecture Shin-Etsu Chemical Co., Ltd. Silicone Electronic Materials Research Laboratory (72) Inventor Yukiko Wakao Matsuida-cho, Usui-gun, Gunma Prefecture Hitomi 1 No. 10 Inside Silicon Electronic Materials Research Laboratory, Shin-Etsu Chemical Co., Ltd. (72) Inventor Shigeki Ino Matsuida-cho, Usui-gun, Gunma No. 1 Hitomi 10 Shin-Etsu Chemical Industrial Co., Ltd. Silicon Electronic Materials Research Laboratory

Claims (4)

[Claims] 1. An epoxy resin composition for semiconductor encapsulation comprising an epoxy resin, a curing agent, an inorganic filler and a curing catalyst as essential components, wherein the curing catalyst is represented by the following general formula (1): ] (Wherein R ¹ represents an electron-donating substituent), and an addition reaction product of an organic phosphorus compound and a compound having one or more conjugated double bonds in one molecule is used. The epoxy resin composition for semiconductor encapsulation. 2. An organic phosphorus compound of the formula (1), wherein R ¹ is an alkoxy group having 1 to 4 carbon atoms, an alkyl group having 1 to 4 carbon atoms, an amino group or an alkyl group is a dialkylamino group having 1 to 4 carbon atoms. The composition according to claim 1, wherein an addition reaction product of the compound and maleic anhydride or a quinone is used as a curing catalyst. 3. The composition according to claim 1, wherein a biphenyl type epoxy resin is used as the epoxy resin. 4. A semiconductor device encapsulated with the cured product of the composition according to claim 1, 2.