JP3432445B2 - Epoxy resin composition for optical semiconductor and semiconductor device - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an epoxy resin composition for optical semiconductor encapsulation which is excellent in heat resistance and adhesion.

[0002]

2. Description of the Related Art Conventionally, in order to seal a light emitting diode element by transfer molding, a mixture of a bisphenol A type epoxy resin as a sealing resin and an acid anhydride as a curing agent has been used. Since this resin system has a high light transmittance in a wide wavelength range and a high adhesive force with a light emitting diode element, it has a high reliability such as current-carrying characteristics and has been widely used. However, in recent years, with the shift of the in-vehicle semiconductor device into the engine room, reliability at higher temperatures has been required. Therefore, the conventional mixture of bisphenol A type epoxy resin and acid anhydride cannot maintain sufficient reliability. In particular, in a thermal stress test such as a temperature cycle test, the test treatment temperature in a high temperature range rises, so that a sealing material of a mixture of bisphenol A type epoxy and an acid anhydride, which has a low heat resistance, causes defects early. On the other hand, the mixture of cresol novolac type epoxy resin and phenol novolac resin, which has been used for the light receiving element up to now, is considered to be applied to the sealing of the light emitting diode element because of its high heat resistance. Since the adhesion to the device is low, the life after sealing is short and it cannot be used for a light emitting diode device. Therefore, a resin composition having excellent heat resistance and adhesiveness is required for an optical semiconductor device used in a high temperature environment.

[0003]

DISCLOSURE OF THE INVENTION The present invention provides an epoxy resin composition for encapsulating a light emitting diode element, which has high heat resistance, excellent adhesion, and high light transmission.

[0004]

The present invention comprises (A) 75% by weight or more of the total epoxy resin of the biphenyl type epoxy resin represented by the general formula (1), and (B) ICI at 150 ° C.
A phenol aralkyl resin represented by the general formula (2) having a viscosity of 3 to 30 poise, and a resin composition containing (C) a curing accelerator as an essential component, wherein (A) a biphenyl type represented by the general formula (1) in advance. Epoxy resin and (B) at 150 ° C
An epoxy resin composition for optical semiconductor encapsulation, wherein the phenol aralkyl resin represented by the general formula (2) having an ICI viscosity of 3 to 30 poise is melt mixed.
And an optical semiconductor device sealed by using the same.

[Chemical 3] (R1 is selected from hydrogen, methyl group and ethyl group and may be the same or different. N is an integer of 0 to 2)

[0005]

[Chemical 4] (R ₂ is a phenylene group, a diphenylene group, a diphenylene ether group, a diphenylene methane group, or those groups each having a substituent and an alkyl group having 1 to 5 carbon atoms, l
Is 0 or an integer of 1 to 3, R ₃ is an alkyl group having 1 to 4 carbon atoms, and n is an integer of 0 to 10)

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The biphenyl type epoxy resin represented by the general formula (1) used in the present invention is characterized in that it has a low viscosity when heated while being in a crystalline state at room temperature. The crystalline fine particles remain in the cured product after the light emitting diode element is sealed by using the resin composition produced by blending with the above raw material and kneading with a roll or the like. The fine particles adversely affect the light transmittance. In particular, since fine particles remain on the light emitting diode element after sealing, the light emission intensity is significantly reduced, and therefore it is necessary to completely eliminate it. As a result of various studies, the inventor of the present invention has prepared a resin composition produced by using a mixture of a biphenyl type epoxy resin represented by the general formula (1) and a phenol aralkyl resin represented by the following general formula (2) that are melted in advance. It was found that crystalline fine particles due to the biphenyl type epoxy resin did not remain in the cured product. The biphenyl type epoxy resin represented by the general formula (1) includes 4,4 ′
-Bis (2,3-epoxypropoxy) -3,3 ',
5,5′-Tetramethylbiphenyl is preferable in terms of adhesion and uniformity after melt-kneading.

A molten mixture of the biphenyl type epoxy resin represented by the general formula (1) and the phenol aralkyl resin represented by the following general formula (2) has a temperature of 120 ° C to 150 ° C.
It can be obtained in 1 to 5 hours. It can be visually confirmed that the obtained molten mixture does not contain crystalline fine particles. The biphenyl type epoxy resin represented by the general formula (1) can be used in combination with another epoxy resin. Epoxy resins that can be used in combination refer to all monomers, oligomers and polymers having two or more epoxy groups in one molecule, for example, cresol novolac type epoxy resin,
Examples thereof include phenol novolac type epoxy resin, naphthalene type epoxy resin, trifunctional epoxy resin, and dicyclopentadiene-modified phenol type epoxy resin. As the epoxy resin used in combination, in order to maintain the high adhesion of the biphenyl type epoxy resin of the general formula (1), it is necessary to suppress it to 25% by weight or less in the total epoxy resin.

The phenol aralkyl resin represented by the general formula (2) used in the present invention is used to enhance the adhesion to the light emitting diode element and prevent the deterioration of the current-carrying characteristics during continuous light emission. Furthermore, in order to prevent the formation of burrs and voids during molding, 15% of the phenol aralkyl resin represented by the general formula (2) is used.
The ICI viscosity at 0 ° C. is preferably 3 to 30 poise. This is because the biphenyl type epoxy resin of the general formula (1) has a considerably low viscosity, and therefore the viscosity of the mixture obtained by melting the both resins depends on the viscosity of the phenol aralkyl resin represented by the general formula (2). Among the phenol aralkyl resins represented by the general formula (2), the resin having the following structure is preferable in terms of the balance of adhesion and heat resistance.

[Chemical 5]

The phenol aralkyl resin represented by the general formula (2) can be used in combination with other phenol resins. The phenol resin which can be used in combination refers to all monomers, oligomers and polymers having two or more functional groups capable of reacting with an epoxy group in one molecule, and examples thereof include phenol novolac resin and bisphenol M. The equivalent ratio of the total epoxy resin and the total phenol resin used in the present invention is preferably 0.8 to 1.2. The curing accelerator used in the present invention may be any one as long as it accelerates the reaction between an epoxy group and a hydroxyl group, and those generally used for encapsulating materials can be widely used, for example, 1,8-
Examples thereof include diazabicyclo (5,4,0) undecene-7, triphenylphosphine, dimethylbenzylamine, 2-methylimidazole and the like. These may be used alone or in combination.

The resin composition of the present invention comprises a melt mixture of (A) a biphenyl type epoxy resin represented by the general formula (1) and (B) a phenol aralkyl resin represented by the general formula (2) in advance, and (C) curing. Although the accelerator is an essential component, an azo-based dye, a quinone-based dye, a release agent such as montanic acid, and an antioxidant may be added as necessary.

Production Example 1 of Melt Mixture Biphenyl type epoxy resin (Yukaka Shell Epoxy Co., Ltd.)
・ YX-4000H, melting point 104 ° C., epoxy equivalent 1
95) 52.1 parts by weight and formula (2-1) (softening point 85 ° C.,
Hydroxyl equivalent 175, ICI viscosity 10 poise / 150 ° C)
After melt-mixing 46.9 parts by weight at 130 ° C. for 2 hours, it was confirmed that fine particles due to the crystalline epoxy resin did not remain, and then pulverized to obtain a powder. The obtained powder is referred to as a melt mixture 1. Production Examples 2 to 5 of melted mixture Biphenyl type epoxy resin (YX-4000H manufactured by Yuka Shell Epoxy Co., Ltd., melting point 104 according to the formulation shown in Table 1)
C., epoxy equivalent 195) and formula (2-1) (softening point 85
° C, hydroxyl equivalent 175, ICI viscosity 10 poise / 150
(° C) was melt-mixed at 130 ° C for 2 hours, and after confirming that fine particles due to the crystalline epoxy resin did not remain, the powder was pulverized to obtain a powder. The obtained powders are referred to as melt mixtures 2 to 5, respectively.

[0012]

Example 1 Melt Mixture 1 99.0 parts by weight 1,8-diazabicyclo (5,4,0) undecene-7 (hereinafter referred to as DBU) 0.5 parts by weight Montanic acid wax 0.5 parts by weight After crushing, they were mixed, heated and kneaded using a twin-screw kneader at 70 to 90 ° C., cooled and solidified, and then crushed to obtain a resin composition powder. A light emitting diode device was obtained by sealing the light emitting diode element of this resin composition under the conditions of 150 ° C., 70 kg / cm ² , and 180 seconds using a low pressure transfer molding machine. It evaluated by the method shown below. The results are shown in Table 1.

Evaluation Method Temperature Cycle Test: The temperature cycle property was measured using the light emitting diode device obtained above. The measurement conditions were such that the low temperature side was −65 ° C./5 minutes and the high temperature side was 125 ° C./5 minutes as one cycle. The measurement was carried out by repeating the above-mentioned cycle a plurality of times and judging by the number of cycles in which a resin crack occurred. Light transmittance: The resin composition was molded into a test piece of 10 × 30 × 1 mm thick under the conditions of 150 ° C., 70 kg / cm ² and 180 seconds using a low pressure transfer molding machine, and then 17
Post-curing was performed at 5 ° C. for 2 hours to obtain a test piece for measuring light transmittance. The obtained test piece was measured for light transmittance (unit:%) at 940 nm using a spectrophotometer (manufactured by Hitachi Ltd., Model 330 self-recording spectrophotometer). Continuous energization test: The continuous energization test was measured using the light emitting diode device obtained above. The measurement conditions were room temperature. The light intensity was defined as 50% or less of the initial value, and the time until the occurrence of the defect was measured. Glass transition temperature (Tg): The resin composition was treated with a low pressure transfer molding machine at 150 ° C., 70 kg / cm ² , 1
After molding into a 5 × 5 × 20 mm test piece under the condition of 80 seconds, post cure at 175 ° C. for 2 hours, and TMA
The test piece for measurement was used. The obtained test piece was measured using a thermomechanical analyzer (manufactured by Seiko Denshi Kogyo KK). The tangent line was drawn at Tg of 40 ° C on the low temperature side and 240 ° C on the high temperature side, and Tg was determined from the intersection of both tangent lines.

Examples 2 and 3 and Comparative Examples 1 to 5 According to the formulations shown in Table 2, resin compositions were obtained in the same manner as in Example 1 and evaluated in the same manner as in Example 1. In Examples 2 and 3 and Comparative Examples 1 and 2, an orthocresol type epoxy resin (softening point 75 ° C., epoxy equivalent 210) was further mixed and kneaded with the melt mixture and other components and kneaded. The phenol novolac resin of Comparative Example 3 has a softening point of 104 ° C. and a hydroxyl group equivalent of 104, and the bisphenol A type epoxy resin of Comparative Example 4 has a softening point of 75 ° C. and an epoxy equivalent of 480. The biphenyl type epoxy resin of Comparative Example 5 and the resin of the formula (2-1) are the same as those used in the melt mixture. The results are shown in Table 2.

[Table 1]

[0015]

[Table 2]

[0016]

According to the present invention, a light emitting diode device having excellent heat resistance and continuous energization characteristics can be obtained.

─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) C08L 63/00-63/10 C08G 59/00-59/72 H01L 23/29 H01L 23/31

Claims (2)

(57) [Claims] 1. A biphenyl type epoxy resin represented by the general formula (1) in an amount of (A) total epoxy resin of 75% by weight or more, and (B) an ICI viscosity at 150 ° C. of 3 to 30 poises.
A phenolic aralkyl resin represented by a general formula (2) and a resin composition containing (C) a curing accelerator as an essential component, and (A) a biphenyl epoxy resin represented by the general formula (1) and (B) 150 ICI viscosity at ℃ is 3 to 3
An epoxy resin composition for encapsulating an optical semiconductor, wherein a phenol aralkyl resin represented by the general formula (2) having 0 poise is melt-mixed. [Chemical 1] (R1 is selected from hydrogen, methyl group and ethyl group and may be the same or different. N is an integer of 0 to 2) (R2 is a phenylene group, a diphenylene group, a diphenylene ether group, a diphenylene methane group, or those groups each having a substituent and an alkyl group having 1 to 5 carbon atoms, l
Is 0 or an integer of 1 to 3, R 3 is an alkyl group having 1 to 4 carbon atoms, and n is an integer of 0 to 10) 2. An optical semiconductor device obtained by encapsulating a light emitting diode element using the epoxy resin composition according to claim 1.