JP2526740B2 - Light-transmissive epoxy resin composition and optical semiconductor device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light-transmissive epoxy resin composition suitable for encapsulation of semiconductors such as LEDs, CCDs, photocouplers, etc. which function by transmitting and receiving optical signals, and the epoxy resin composition. The present invention relates to an optical semiconductor device sealed with a cured product.

[0002]

2. Description of the Related Art
Epoxy resin is known as a resin having excellent electrical properties, moisture resistance, heat resistance, etc., and in particular, acid anhydride curing type epoxy resin composition is widely used for encapsulation of optical semiconductors because of its excellent transparency. .

On the other hand, it is generally practiced to mix an inorganic filler such as silica into the epoxy resin composition as a means for lowering the linear expansion coefficient and lowering the stress.

However, a cured product obtained from an epoxy resin composition containing an inorganic filler such as silica is opaque even if the epoxy resin itself is transparent and the filler is also transparent. . This refractive index n _D at 25 ° C. of cured epoxy resin is about 1.5 to 1.7, the refractive index of the filler (e.g. refractive index n _D ≒ 1.458 at 25 ° C. of SiO ₂₎ This is because the difference between the two causes light scattering. Therefore, the transparency of the cured product can be obtained by adding a filler having a refractive index close to that of the cured product of the epoxy resin component.

However, according to the study by the present inventor, when an epoxy resin component which gives a cured product having an approximate refractive index and a filler are blended, the wettability of the epoxy resin component to the filler particles is insufficient. However, there is a slight void or peeling at the interface between the two, which causes light scattering, which causes a problem that the transparency that should be obtained cannot be obtained. In this case, in order to improve the wettability, the surface treatment of the filler with a silane coupling agent or the like has been conventionally performed, and this surface treatment method improves transparency as well as mechanical properties such as bending strength. It can be said to be an effective means. However, as will be understood from Comparative Examples described below, the transparency of the cured product of the epoxy resin composition obtained by blending the filler treated with the silane coupling agent is not sufficient, and is suitable for optical semiconductor encapsulation. Was hard to say.

The present invention has been made in view of the above circumstances.
Provided are a light-transmissive epoxy resin composition which gives a cured product having excellent transparency, low stress and excellent mechanical strength, and an optical semiconductor device encapsulated with the light-transmissive epoxy resin composition. The purpose is to

[0007]

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 compound of a compound having two or more epoxy groups in one molecule and an acid anhydride curing agent are used. A compound and / or an acid anhydride-based curing agent having two or more epoxy groups in one molecule with a filler having the same refractive index as that of the cured product of the epoxy resin component in the epoxy resin composition contained as a resin component. When blended with a surface-treating agent comprising an organic silicon compound and an organosilicon compound, the wettability between the epoxy resin component and the surface-treated filler is remarkably improved and the interface adhesion is increased.
Since there is substantially no difference in the refractive index between the two, light scattering is greatly reduced, and therefore, a cured product having excellent transparency, low stress, good crack resistance, and excellent mechanical strength. A light-transmissive epoxy resin composition that gives an optical semiconductor device encapsulated with a cured product of such an epoxy resin composition is obtained compared with a conventional light-transmissive epoxy resin-encapsulated optical semiconductor device. Finding that the function is exerted effectively,
The present invention has been completed.

Therefore, the present invention provides (A) a compound having two or more epoxy groups in one molecule, (B) an acid anhydride-based curing agent, (C) the component (A) and the component (B). Filling in which a filler having substantially the same refractive index as that of the cured product is surface-treated with a compound having two or more epoxy groups in one molecule and / or a surface treating agent comprising an acid anhydride-based curing agent and an organic silicon compound. Provided are a light-transmissive epoxy resin composition containing an agent, and an optical semiconductor device encapsulated with the light-transmissive epoxy resin composition.

The present invention will be described in more detail below. As the compound having two or more epoxy groups in one molecule of the component (A) which constitutes the light-transmitting epoxy resin composition of the present invention, it has been conventionally known. The various epoxy resins mentioned above can be used in liquid or solid form. Specific examples thereof include epoxy resins synthesized from various novolak resins such as epichlorohydrin and bisphenol, alicyclic epoxy resins, and epoxy resins having halogen atoms such as chlorine and bromine atoms introduced therein. The seeds may be used alone or in combination of two or more.

Of these, a bisphenol type epoxy resin that is particularly less colored is preferable, and specific products include, for example, Epicoat 828, Epicoat 1001, Epicoat 1004 (trade names of Yuka Shell Epoxy Co., Ltd.), RE310S, RE304S ( As above, manufactured by Nippon Kayaku Co., Ltd.), DER332, DER661, DER6
64 (above, product name of Dow Chemical Co., Ltd.) and the like.

As the acid anhydride type curing agent as the component (B), any of those generally used for curing an epoxy resin can be used. For example, methylhexahydrophthalic anhydride, hexahydrophthalic anhydride, tetrahydro. Examples thereof include phthalic anhydride, phthalic anhydride, trimellitic anhydride, pyromellitic dianhydride, and among them, those not containing an aromatic ring such as hexahydrophthalic anhydride and tetrahydrophthalic anhydride are preferable. The acid anhydride-based curing agent may be added in the usual amount, but the component (A) 10
It is preferably 10 to 150 parts by weight with respect to 0 parts by weight.

In the epoxy resin composition of the present invention,
As the component (C), a compound treated with a compound having two or more epoxy groups in one molecule and / or a surface treatment agent composed of an acid anhydride type curing agent and an organic silicon compound is blended.

Here, as the filler, for example, silica,
Alumina, aluminum nitride, boron nitride, silica-titania glass, silica-alumina glass, etc. can be used,
In particular, silica-titania glass has a refractive index n at 25 ° C. of the filler by changing the composition of SiO ₂ / TiO _2.
It is effective and preferable because _D can be adjusted.

Further, as the silica-titania glass particles, from 900 nm to 6 by a linear transmittance measuring method M described below.
Linear transmittance of 70% or more, especially 8 in the wavelength range of 00 nm
Those of 0% or more can be preferably used.

M: A bisphenol type epoxy resin represented by the following general formula (1) or a novolac type epoxy resin represented by the following general formula (2) and phenyl glycidyl ether are mixed to obtain silica-titania glass particles. A solution having a refractive index difference of ± 0.002 or less is prepared. This solution and silica-titania glass particles crushed to an average particle size of 5 to 30 μm are mixed at a weight ratio of 1: 1 and the linear transmittance of the mixture is measured with an optical path length of 1 mm.

[0016]

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The method of producing such highly transparent silica-titania glass particles can be carried out according to the sol-gel method described in Japanese Patent Application No. 2-028077 previously proposed by the present applicant.

That is, first, as a starting material, Si (OCH
₃ ) ₄ , silicon alkoxide such as Si (OC ₂ H ₅ ) ₄ and titanium alkoxide such as Ti (OC ₃ H ₇ ) ₄ and Ti (OC ₄ H ₉ ) ₄ are used.

[0019] In this case, it is preferable to use a silicon alkoxide and a titanium alkoxide in an amount such that 10 to 18 mol% of TiO ₂ with respect to the total of SiO ₂ and TiO _2. If the content of TiO ₂ does not reach 10 mol%, the silica-titania glass particles obtained may not have a refractive index of 1.53 or more, which is considered to be preferable as a filler for epoxy resin, while 18 mol %, It may be difficult to obtain a transparent epoxy resin having the same refractive index as that of the silica-titania glass particles.

As a method for obtaining a sol or gel from these raw materials, methanol, ethanol as a solvent for diluting the above silicon alkoxide and titanium alkoxide,
Dissolve in alcohol such as propanol, add water to this and hydrolyze to make silica-titania sol, transfer this sol to a container for gelation, seal it, and let it stand in a thermostatic dryer. A method of allowing the solution to stand and gelling is preferably adopted. In this case, regarding the gelation temperature and the aging temperature after gelation, if the temperature is lower than 60 ° C., the hydrolysis of the alkoxide may be incomplete, which causes coloring in the sintering step described later. Trivalent T
Since the i-ions are easily generated, the gelation and aging temperature is preferably 60 ° C. or higher. The aging is carried out for 1 hour or longer, preferably 5 hours or longer, in order to complete the hydrolysis.

Next, the method for drying the wet gel after the gelation and aging is not particularly limited, but for example, the lid of the closed container used for aging the gel is removed and left as it is in a constant temperature oven. It is possible to employ a method of obtaining a dry gel by drying by drying.

Further, the dry gel thus obtained is crushed and then sintered. Here, the crushing method is not particularly limited, and the particle size is appropriately selected, and an appropriate crushing method and particle size can be adopted according to the application, but the average particle size is 1 to 100 μm.
m, particularly preferably 5 to 30 μm. .

Finally, the crushed dry gel is sintered and vitrified, and it is preferable to carry out the sintering at a temperature in the range of 1050 to 1250 ° C. When the sintering temperature is less than 1050 ° C., the particles are not completely and uniformly densified. Therefore, when the transmittance of the silica-titania glass particles is measured, the light incident on the inside of the particles is the same as the silica-titania glass constituent particles. Because of the scattering due to the difference in refractive index between the pores of the constituent particles, it may be possible to obtain a low transmittance value as a result. In addition, when the sintering temperature is higher than 1250 ° C., Anas which is one of the crystal phases of TiO ₂
Since the precipitation of the e phase occurs, silica-titania glass particles having excellent light transmittance may not be obtained even in this temperature range.

The sintering method is not particularly limited as long as it is within the above temperature range, but a sintering furnace such as an electric furnace which is kept at a constant temperature is used, and air, oxygen gas or oxygen is used in the furnace. It is preferable to introduce a mixed gas with air to create an oxidizing atmosphere in the furnace in order to prevent generation of trivalent Ti ions which causes coloring. In addition, the rate of temperature increase until reaching a predetermined temperature is usually preferably 10 to 500 ° C./hour. The sintering time is usually 10 to 300 in the above temperature range.
Minutes.

In the present invention, the above-mentioned filler such as silica-titania glass particles is an epoxy composed of the component (A) and the component (B) in order to minimize light scattering when blended with the epoxy resin. It is necessary that the refractive index of the cured product of the resin component is substantially the same. In particular,
The refractive index difference is within ± 0.01, preferably within ± 0.005, and more preferably within ± 0.002.

Further, the compound having two or more epoxy groups in one molecule and the acid anhydride type curing agent used as the surface treatment agent for the above-mentioned filler are the components (A) and (B) in the composition of the present invention, respectively. Although a compound that can be blended as the component) can be used, the same compound as the components (A) and (B) or different compounds can be used.

As the organosilicon compound as the surface treatment agent, silanes and organopolysiloxanes represented by the following formulas can be mentioned as typical ones, and one of these can be used alone or two can be used. The above can be used in combination.

[0028]

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In the present invention, the compounding ratio of the above three components as the surface treatment agent is such that (a) the compound having two or more epoxy groups in one molecule, (b) the acid anhydride curing agent, and the organosilicon. When the compound is (c), i) When a mixture of (a) and (c) is used as a treating agent (a) / (c) = 50/50 to 99/1 ii) As a treating agent (b) When using a mixture of (c) (b) / (c) = 50/50 to 99/1 iii) When using a mixture of (a), (b) and (c) as a treating agent (a) / (b) ) = 50/50 to 85/15 and [(a) + (b)] / (c) = 50/50 to 99/1 (both are weight ratios).

In the present invention, it is preferable that the surface treatment agent comprising the above three components and the filler have similar refractive indexes, and the difference in refractive index between them is within ± 0.1, particularly within ± 0.05. It is desirable to adjust the refractive index to such a value.

The surface treatment of the filler with the above-mentioned surface treatment agent can be carried out by a dry method or a wet method. As a dry method, known means may be adopted, for example, a filler is put in a high-speed mixer having a high-speed rotation and a large shearing force and a heating device, and a surface treatment agent diluted with a solvent is added by spraying or the like and mixed and stirred. Any industrially generalized method of carrying out can be adopted. On the other hand, as the wet method, an ordinary method in which a filler, a surface treatment agent and a solvent are mixed and stirred and then the solvent is removed can be adopted.

In this case, the kind of the solvent is not particularly limited, but it is desirable to appropriately select it, because the difference in the adsorbability of the surface treatment agent to the filler appears, but specifically, toluene, methyl ethyl ketone, methyl isobutyl. A ketone or the like can be preferably used. Also, after removing the solvent,
It is also effective to heat at 100 to 600 ° C.

The compounding amount (adhesion amount) of the surface treatment agent with respect to the filler is 0.1 to 5 parts by weight, particularly 0.5 to 2 parts by weight, of the surface treatment agent to 100 parts by weight of the filler. can do.

The amount of the filler thus surface-treated is 10 to 600 parts by weight based on 100 parts by weight of the total amount of the components (A) and (B) as the epoxy resin component,
In particular, it is preferably 100 to 300 parts by weight, and 10
If the amount is less than 600 parts by weight, the effect of imparting low shrinkage and low expansion may not be sufficiently exhibited, while if the amount is more than 600 parts by weight, the viscosity of the composition may be too high.

Further, in the present invention, the above-mentioned (A)
It is preferable to optionally add a curing accelerator for the purpose of promoting the reaction between the component and the component (B). Examples of the curing accelerator include 2-imidazole or its derivative.
Ethyl-4-methylimidazole, 2-phenylimidazole, 1-cyanoethyl-2-methylimidazole, and the like, as a tertiary amine derivative 1,8-diaza-bicyclo (5.4.0) undecene-7 (DBU), benzyl. Examples of the phosphine-based derivative such as dimethylamine include triphenylphosphine and nonyldiphenylphosphine. The amount of the curing accelerator may be a normally used amount, but 10 parts by weight or less, particularly 0.1 to 10 parts by weight, based on 100 parts by weight of the total of both components (A) and (B). It is suitable.

In the present invention, an anti-tarnish agent may be added as an optional component. As the discoloration preventing agent, for example, triphenyl phosphite, tridecyl phosphite, nonyl diphenyl phosphite as a reducing organic phosphorus compound, 9,10
2,6-di-t as a hindered phenol such as -dihydro-9-oxa-10-phosphaphenanthrene, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide. -Butyl-4-methylphenol (BHT), 2,4,6-tricyclohexylphenol, 2,4,6-tribenzylphenol and the like, as a thioether compound, dilauryl-
3,3'-thiodipropionate, ditridecyl-3,
3'-thiodipropionate, [4,4'-thiobis (3-methyl-6-tert-butylphenyl)]-bis (alkylthiopropionate) and the like, and one of these alone or Two or more kinds can be used in combination. The blending amount of this discoloration preventing agent may be a normal amount, but the total amount of both components (A) and (B) is 100.
0.1 to 10 parts by weight is preferable with respect to parts by weight.

In addition to the above-mentioned components, various additives can be added to the composition of the present invention as optional components within a range that does not impair the effects of the present invention. A curing accelerator, a stress reducing agent, a release agent, a visible light blocking agent, a flame retardant and the like can be appropriately added.

When the light-transmissive epoxy resin composition of the present invention is produced, it can be obtained by uniformly stirring and mixing the predetermined amounts of the above-mentioned components. At this time, various mixers, kneaders, rolls, and extruders are used. It can be performed using a ruder or the like. There is no particular limitation on the order of mixing the components.

The composition of the present invention can be suitably used for encapsulation of optical semiconductors regardless of the properties of the resin component. If it is liquid at room temperature, it can be molded by a potting method, casting method or the like. If it is solid at room temperature, it can be transferred. Molding and injection molding can be adopted. In this case, the molding temperature is 80 to 160 ° C., and the post cure is 140 to 16
It is preferred to carry out at 0 ° C. for 2 to 16 hours. When using the composition of the present invention, in order to exhibit high transparency,
When a part or all of the epoxy resin composition is a solid, it is effective to heat and melt it with the necessary all components or a part thereof in advance, or to mix them after dissolving them in a solvent. It is also possible to employ a method in which the solvent is mixed with the solvent and then the solvent is stripped.

[0040]

EXAMPLES The present invention will be specifically described below 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. Prior to each example, a production example of the surface-treated filler used in each example will be shown.

[Production Example] (Production of Filler) According to the sol-gel method described in Japanese Patent Application No. 2-8077 previously proposed by the present applicant, highly transparent silica-titania glass particles were produced by the following method. . Silica-titania glass particles
-I Tetramethoxysilane (trade name KBM04, manufactured by Shin-Etsu Chemical Co., Ltd.) 1522.2 g and methanol (manufactured by Wako Pure Chemical Industries, special grade) 3220.4 g, 0.2N hydrochloric acid aqueous solution 180 ml at 30 ° C for 15 minutes After dropping over 30 ℃
It was stirred for 1 hour. Next, 513.5 g of tetra-normal butyl titanate (manufactured by Nippon Soda Co., Ltd.) and 16 of methanol
0.2g of solution was added dropwise at 30 ° C over 1 hour,
After stirring for 1 hour at room temperature, 648.6 g of pure water was added at 30 ° C for 15 hours.
The mixture was added dropwise over a period of minutes, and further stirred at 30 ° C. for 10 minutes.

When the obtained silica-titania sol was placed in a polypropylene container and sealed at 90 ° C., the sol gelled after about 30 minutes. The gel was aged at 60 ° C. for 12 hours as it was, and then the container lid was removed and dried at 90 ° C. for 3 days to obtain a dried gel body. This was crushed with a ball mill made of alumina, and the crushed dry gel body was put into a box-type electric furnace, and N ₂ 1.4 m ³ / h, 50 up to 500 ° C.
From 0 ℃ 1100 under the condition of dry air 14m ³ / h
When the temperature was raised to 13 ° C over 13 hours and the temperature was maintained at 1100 ° C for 30 minutes, silica-titania glass particles having the refractive index, the light transmittance and the average particle diameter shown in Table 1 were obtained.

Silica-titania glass particles-II According to the prescription of silica-titania glass particles-I, 1522.2 g of tetramethoxysilane and 320.4 of methanol.
g solution, 0.2N hydrochloric acid aqueous solution 180 ml, tetranormal butyl titanate 675.0 g and methanol 16
A sol was prepared, aged, dried and sintered from 0.2 g of solution and 682.8 g of pure water under the same conditions as in the above-mentioned production method. As a result, the refractive index, the light transmittance and the average particle diameter shown in Table 1 were measured. The resulting silica-titania glass particles-II was obtained.

[0044]

[Table 1]

In this case, the refractive index, light transmittance and average particle diameter were measured by the following methods. Measurement method of refractive index It was measured by Abbe refractometer 3T manufactured by Atago. Method for measuring light transmittance TiO ₂ —SiO ₂ particles having an average particle size of 5 to 30 μm were mixed with Ti
A mixed liquid of Epicoat 828 (epoxy resin manufactured by Yuka Shell Epoxy Co., Ltd.) and phenylglycidyl ether (dipping liquid) in which the mixing ratio was adjusted so that the refractive index calculated from the O ₂ content was within ± 0.002. ) Was mixed in a weight ratio of 1: 1. After the particles were sufficiently dispersed, degassing under reduced pressure was performed until no bubbles were visually observed. This mixture was put into a cell having an optical path length of 1 mm, and a transmittance spectrum was measured in a wavelength range of 900 nm to 400 nm using a spectrophotometer. In this case, the reference is blank. Incidentally, silica-titania glass particles-I
And II, respectively, have a refractive index n _{D at} 25 ° C.
= 1.5248 and 1.5705 mixed liquid was prepared and used for measurement as an immersion liquid. Measurement method of particle size distribution A 0.2% by weight aqueous solution of sodium hexametaphosphate was used as a dispersion medium for the sample, and the particle size distribution measured by a Shimadzu centrifugal sedimentation type particle size distribution analyzer SA-CP3L was measured to obtain an average particle size. I asked.

(Surface Treatment of Filler ) Filler a 200g of silica-titania glass particles-I was placed in a four-necked flask having an internal volume of 1 liter equipped with a reflux condenser, a thermometer, a stirrer, an ester adapter and a dropping funnel. And 500 g of toluene were added, and azeotropic dehydration was carried out for 1 hour while stirring at the reflux temperature. Epoxidized bisphenol AI (trade name: Epicoat 828, manufactured by Yuka Shell Epoxy Co.) 1.93 g, γ-glycidoxypropyltrimethoxysilane (trade name: KBM403, manufactured by Shin-Etsu Chemical Co., Ltd.) 0.47 g. , 1,8-diazabicyclo (5.4.0) undecene-7 (hereinafter abbreviated as DBU)
A surface treatment agent solution containing 0.02 g and 20 g of toluene was added dropwise for 5 minutes, and the mixture was further stirred at reflux temperature for 4 hours. The solvent in this reaction mixture was distilled off under reduced pressure and dried at a temperature of 120 ° C. for 12 hours to obtain a surface-treated filler a. Filler b 200 g of silica-titania glass particles-I was epoxidized bisphenol A-using the same equipment as filler a.
I is 1.27 g, methylhexahydrophthalic anhydride (trade name: RIKACID MH-700, manufactured by Shin Nippon Rika Co., Ltd.) is 1.12 g, γ-glycidoxypropyltrimethoxysilane is 0.01 g, and DBU is 0. 02g, 2 toluene
The surface-treating agent solution prepared by mixing 0 g was treated under the same conditions as for the filler a to obtain a filler b. Filler c Using the same equipment as Filler a, 200 g of silica-titania glass particles-II was added to epoxidized bisphenol A.
-II (trade name: Epicoat 1001, manufactured by Yuka Shell Epoxy Co., Ltd.) 1.93 g, 0.47 g of γ-glycidoxypropyltrimethoxysilane, 0.02 g of DBU, and 20 g of toluene. The same treatment was performed to obtain a filler c. Filler d Using the same equipment as filler a, 200 g of silica-titania glass particles-II was added to epoxidized bisphenol A.
-II 1.27 g, hexahydrophthalic anhydride (trade name: RIKACID HH, manufactured by Shin Nippon Rika Co., Ltd.) 1.12 g, γ
-Glycidoxypropyltrimethoxysilane 0.01
g, DBU 0.02 g, and toluene 20 g were treated under the same conditions as the filler a to obtain a filler d. Fillers e, f, g, h Fillers a, b, c, d except that tetramethoxysilane (trade name: KBM04, manufactured by Shin-Etsu Chemical Co., Ltd.) is used instead of γ-glycidoxypropyltrimethoxysilane. The same treatment as described in (1) above was performed to obtain fillers e, f, g and h, respectively. Filler i, j Using the same equipment as the filler a, 200 g each of silica-titania glass particles-I and II were added to 2.4 g of γ-glycidoxypropyltrimethoxysilane, DBU0.02.
g, a surface treatment agent solution consisting of 20 g of toluene and a filler a
Were treated under the same conditions as above to obtain fillers i and j, respectively. Filler k, m The same treatments as those for the fillers i and j were carried out except that tetramethoxysilane was used instead of γ-glycidoxypropyltrimethoxysilane to obtain fillers k and m, respectively.

[Examples, Comparative Examples] (Examples 1, 2, 5, 6, Comparative Examples 1, 3, 5) Bisphenol A type epoxy resin-I (trade name: Epicoat 828, epoxy equivalent 190, liquid at room temperature) , Yuka Shell Epoxy Co., Ltd.) 53.1 parts, methylhexahydrophthalic anhydride (trade name: RIKACID MH-700, liquid at room temperature, manufactured by Shin Nippon Rika Co., Ltd.) 46.9 parts, 2-ethyl-4-
Methylimidazole (trade name: Curezol 2E4M
Z, Shikoku Chemicals Co., Ltd.) 1 part, triphenyl phosphite (Wako Pure Chemical Industries, Ltd.) 2 parts, γ-glycidoxypropyltrimethoxysilane (trade name: KBM403, Shin-Etsu Chemical Co., Ltd.) 100 parts of fillers a, b, e, f, i, k, or untreated silica-titania glass particles-I, each of which is surface-treated with 6 parts of a resin component, are blended,
30 at room temperature while degassing using a mixer
After stirring and mixing for 7 minutes, 7 kinds of light transmissive epoxy resin compositions which were liquid at room temperature were prepared.

(Examples 3, 4, 7, 8 and Comparative Examples 2, 4,
6) Bisphenol A type epoxy resin-II (trade name:
Epicoat 1001, epoxy equivalent 475, softening point 64
C., 75.5 parts by Yuka Shell Epoxy Co., Ltd., hexahydrophthalic anhydride (trade name: RIKACID HH, melting point 36)
24.5 parts by weight, manufactured by Shin Nippon Rika Co., Ltd., 2 parts by weight of triphenyl phosphite, and 0.6 parts by weight of γ-glycidoxypropyltrimethoxysilane. , G, h, j, m or untreated silica-
100 parts of titania glass particles-II were blended, melt-mixed at 70 ° C. for 15 minutes while performing degassing under reduced pressure using a mixer, 1 part of 2-ethyl-4-methylimidazole was added, and again 70 ° C. under reduced pressure. Were mixed for 5 minutes to prepare 7 kinds of light transmissive epoxy resin compositions which were solid at room temperature.

(Comparative Examples 7 and 8) Liquid or solid type light transmission was carried out at room temperature by the same compounding and manufacturing method as in Comparative Example 5 or 6 except that 100 parts of silica-titania glass particles-I or II were not compounded. Epoxy resin composition was prepared.

Next, test pieces were prepared from these epoxy resin compositions under the molding conditions and after-curing conditions shown in Table 2, and the following tests were conducted.

[0051]

[Table 2]

A test piece having a light transmittance of 10 × 50 × 1 mm was prepared, and the light transmittance at 500,589,700 nm was measured using an absorptiometer. A test piece having a glass transition temperature and a coefficient of linear expansion of 5 × 5 × 15 mm was prepared, and the temperature was raised by a dilatometer at a rate of 5 ° C./min for measurement. Crack resistance 9.0 × 4.5 × 0.5mm size silicon chip is bonded to 14PIN-IC frame (42 alloy),
After sealing this with an epoxy resin composition under the molding conditions and after-curing conditions shown in Tables 3 to 7, -50 ° C x 3
A heat cycle of 0 minutes to 150 ° C. × 30 minutes was repeatedly added, and the resin crack occurrence rate after 200 cycles was measured. The above results are shown in Tables 3-7.

[0053]

[Table 3]

[0054]

[Table 4]

[0055]

[Table 5]

[0056]

[Table 6]

[0057]

[Table 7]

From the results shown in Tables 3 to 7, when silica-titania glass particles were surface-treated with a silane-coupling agent alone (Comparative Examples 1 to 4), the wettability of the interface was slightly improved and the light transmission was improved. The rate was improving, but still insufficient. Further, when untreated silica-titania glass particles are blended (Comparative Examples 5 and 6), although the linear expansion coefficient is lowered and crack resistance is improved, wetting of the interface between the resin component and the silica-titania glass particles is achieved. Since the light transmittance is low, the light transmittance is low, and when no filler is blended (Comparative Examples 7 and 8), the light transmittance is high, but the crack resistance is poor.

On the other hand, the light-transmissive epoxy resin compositions (Examples 1 to 8) of the present invention are further improved in the wettability between the resin component and the filler, and have a high light transmittance. Has a low coefficient of linear expansion of the cured product,
The crack resistance was good.

[Example 9] A photocoupler was assembled using the light-transmitting epoxy resins of Example 1 and Comparative Examples 1 and 5, and the optical coupling efficiency was measured. The drawing is a vertical cross-sectional view of the photocoupler, in which 1 is a light emitting element (gallium arsenide light emitting diode), 2 is a light receiving element (silicon phototransistor), 3 is an inner resin, and a light-transmitting property formed by molding an epoxy resin. The resin 4 is an outer resin, and the carbon-containing molded light-shielding resin 5 is a lead wire.

As a result, when the inner resin is the cured product of the composition of Example 1, the optical coupling efficiencies are 1.3 and 1. as compared with the cured products of the compositions of Comparative Examples 1 and 5, respectively. It was possible to make it 5 times.

[0062]

As described above, in the light-transmissive epoxy resin composition of the present invention, the epoxy compound and / or the filler having a refractive index similar to that of the cured product of the epoxy resin component described above are used.
Alternatively, by blending an acid anhydride-based curing agent and a filler treated with a surface treatment agent composed of an organosilicon compound, the wettability between the resin component and the filler is good, the transparency is high, and the shrinkage is low. Rate, low expansion coefficient, low stress, and excellent mechanical strength, it has excellent optical functionality and reliability.
It can be suitably used for encapsulation of optical semiconductors such as D, CCD, and photo coupler. Further, the optical semiconductor device sealed with the light transmissive epoxy resin composition of the present invention effectively exhibits optical functionality and is excellent in reliability.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a photocoupler used in an example.

[Explanation of symbols]

 1 Light emitting element 2 Light receiving element 3 Inner resin 4 Outer resin 5 Lead wire

Claims (2)

(57) [Claims] 1. (A) a compound having two or more epoxy groups in one molecule, (B) an acid anhydride-based curing agent, (C) a cured product of the (A) component and the (B) component, and refraction Containing a filler having substantially the same ratio with a surface treatment agent comprising a compound having two or more epoxy groups in one molecule and / or an acid anhydride curing agent and an organosilicon compound. A light-transmissive epoxy resin composition comprising: 2. An optical semiconductor device encapsulated with the light transmissive epoxy resin composition according to claim 1.