JP2001261933A - Epoxy resin for sealing optical semiconductor element and optical semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an epoxy resin composition for sealing optical semiconductor elements that has a small internal stress and can retain good light permeability all over the wavelength, and provide optical semiconductor devices that are produced by sealing optical semi-conductor elements with this epoxy resin composition. SOLUTION: The objective epoxy resin composition for sealing optical semiconductor elements comprises an epoxy resin, a curing agent and a glass powder wherein the difference between the Abbe's numbers of the cured resin of the components other than the glass powder and that of the glass powder are adjusted to <=5.0.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an epoxy resin composition for encapsulating an optical semiconductor element used for encapsulating an optical semiconductor element, and an optical semiconductor element using the epoxy resin composition for encapsulating an optical semiconductor element. Is related to an optical semiconductor device sealed.

[0002]

2. Description of the Related Art As a resin composition for encapsulating an optical semiconductor element used for encapsulating an optical semiconductor element such as an LED (light emitting diode), transparency of a cured product is required. An epoxy resin composition obtained using an epoxy resin such as a bisphenol A type epoxy resin and a curing agent such as an acid anhydride is widely used.

However, when an optical semiconductor element is sealed with such an epoxy resin composition, internal stress is generated due to distortion caused by a difference in linear expansion coefficient between the epoxy resin and the optical semiconductor element. As a result, the optical semiconductor element is degraded. For example, when the optical semiconductor element is an LED, there is a problem in that the luminance is reduced or a wiring connected to the LED is disconnected.

Therefore, conventionally, as a method for reducing such internal stress, an inorganic powder having a small linear expansion coefficient, such as silica powder or glass powder, is blended into an epoxy resin composition, and the linearity of the epoxy resin composition is reduced. A method has been proposed in which the expansion coefficient is reduced to approximate that of an optical semiconductor device.

[0005]

However, the above method has a fatal drawback as a resin composition for encapsulating an optical semiconductor element, in that the light transmittance of the epoxy resin composition is significantly reduced. . On the other hand, in order to solve the above-mentioned drawbacks, there has been proposed a method for reducing the difference in the refractive index between the resin component and the inorganic powder.

However, in general, since the refractive index of a substance changes depending on the wavelength of light, only a small refractive index between a resin component and an inorganic powder at a specific wavelength provides good light transmission at all wavelengths. Rates are not always available.
That is, even if the difference in the refractive index between the resin component and the inorganic powder is substantially zero at a certain specific wavelength, the difference in the refractive index occurs at a different wavelength. Such a change in the light transmittance due to the wavelength causes a decrease in the function of the optical semiconductor device.

[0007] The present invention has been made in view of such circumstances, and its object is to reduce internal stress,
Moreover, an epoxy resin composition for encapsulating an optical semiconductor element capable of obtaining good light transmittance at all wavelengths, and a light in which an optical semiconductor element is encapsulated by the epoxy resin composition for encapsulating an optical semiconductor element. It is to provide a semiconductor device.

[0008]

In order to achieve the above object, an epoxy resin composition for encapsulating an optical semiconductor element of the present invention comprises an epoxy resin, a curing agent and a glass powder.
The difference between the Abbe number of the cured product obtained by curing the components other than the glass powder of the epoxy resin composition for encapsulating an optical semiconductor element and the Abbe number of the glass powder is 5.0 or less. It is characterized by:

Further, the present invention provides an epoxy resin composition for encapsulating an optical semiconductor element, comprising an epoxy resin, a curing agent, and a glass powder. Cured product obtained by curing a component other than the glass powder of the epoxy resin composition for encapsulating an optical semiconductor element, wherein the difference between the number and the Abbe number of the glass powder is 5.0 or less. The relationship between the refractive index of the glass powder and the refractive index of the glass powder is represented by the following formula (1), and includes the epoxy resin composition for encapsulating an optical semiconductor element.

-0.005 ≦ n ₂ −n ₁ ≦ 0.005 (1) n ₁ : a refractive index n _{2 at} a wavelength of 589.3 nm of a cured product obtained by curing a component other than the glass powder. : Refractive index of the glass powder at a wavelength of 589.3 nm In this epoxy resin composition for encapsulating an optical semiconductor element, the glass powder is preferably a spherical glass powder.

Further, the present invention includes an optical semiconductor device obtained by sealing an optical semiconductor element using the epoxy resin composition for sealing an optical semiconductor element.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The epoxy resin composition for encapsulating an optical semiconductor element of the present invention contains an epoxy resin, a curing agent and glass powder.

Examples of the epoxy resin include bisphenol A epoxy resin, bisphenol F epoxy resin, novolak epoxy resin such as phenol novolak epoxy resin and cresol novolak epoxy resin, alicyclic epoxy resin, triglycidyl isocyanate. Nurate, nitrogen-containing ring epoxy resin such as hydantoin epoxy resin, water-containing bisphenol A type epoxy resin,
Examples include aliphatic epoxy resins, glycidyl ether type epoxy resins, bisphenol S type epoxy resins, biphenyl type epoxy resins, dicyclo ring type epoxy resins, and naphthalene type epoxy resins which are the mainstream of the low water absorption cured type. These may be used alone or in combination. Among these epoxy resins, it is preferable to use bisphenol A type epoxy resin, bisphenol F type epoxy resin, novolak type epoxy resin, alicyclic epoxy resin, and triglycidyl isocyanurate which are excellent in transparency and discoloration resistance.

The epoxy resin may be solid or liquid at room temperature. Generally, the epoxy resin used preferably has an average epoxy equivalent of 90 to 1,000.
In the case of a solid, those having a softening point of 160 ° C. or less are preferred. If the epoxy equivalent is smaller than 90, the cured product of the epoxy resin composition for encapsulating an optical semiconductor element may become brittle. If the epoxy equivalent exceeds 1000, the cured product may have a low glass transition temperature (Tg).

Examples of the curing agent include an acid anhydride curing agent and a phenol curing agent. Examples of the acid anhydride-based curing agent include phthalic anhydride, maleic anhydride, trimellitic anhydride, pyromellitic anhydride, hexahydrophthalic anhydride, tetrahydrophthalic anhydride, methylnadic anhydride, nadic anhydride, glutaric anhydride. acid,
Methyl hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride and the like can be mentioned. These may be used alone or in combination. Among these acid anhydride-based curing agents, it is preferable to use phthalic anhydride, hexahydrophthalic anhydride, tetrahydrophthalic anhydride, and methylhexahydrophthalic anhydride. The acid anhydride-based curing agent preferably has a molecular weight of about 140 to 200, and more preferably a colorless to pale yellow acid anhydride.

Examples of the phenol-based curing agent include phenol novolak resin-based curing agents.

The mixing ratio of the epoxy resin and the curing agent is as follows:
The active group (acid anhydride group or hydroxyl group) capable of reacting with the epoxy group in the curing agent is 0.5 to 1.5 equivalent, and more preferably 0.7 to 1.5 equivalent to 1 equivalent of the epoxy group in the epoxy resin.
It is preferable that the ratio be 1.2 equivalents. When the active group is less than 0.5 equivalent, the curing rate of the epoxy resin composition for encapsulating an optical semiconductor element is reduced, and the glass transition temperature of the cured product may be reduced. If the amount exceeds the equivalent, the moisture resistance may decrease.

Depending on the purpose and use of the curing agent, other than an acid anhydride curing agent and a phenol curing agent, a conventionally known curing agent for an epoxy resin such as an amine curing agent may be used. An acid anhydride-based curing agent partially esterified with alcohol, or a carboxylic acid curing agent such as hexahydrophthalic acid, tetrahydrophthalic acid, methylhexahydrophthalic acid, alone or an acid anhydride-based curing agent And a phenolic curing agent. For example, when a carboxylic acid curing agent is used in combination, the curing speed can be increased, and the productivity can be improved. When these curing agents are used, the compounding ratio may be in accordance with the compounding ratio (equivalent ratio) when using an acid anhydride-based curing agent and a phenol-based curing agent.

The epoxy resin composition for encapsulating an optical semiconductor element of the present invention may further include, if necessary, a conventionally used curing agent such as a curing accelerator, Various known additives such as an inhibitor, a modifier, a silane coupling agent, a defoaming agent, a leveling agent, a release agent, a dye, and a pigment may be appropriately compounded.

The curing accelerator is not particularly restricted but includes, for example, 1,8-diaza-bicyclo (5,4,0) undecene-7, triethylenediamine, tri-2,4,6-dimethyl. Tertiary amines such as aminomethylphenol, imidazoles such as 2-ethyl-4-methylimidazole and 2-methylimidazole, triphenylphosphine, tetraphenylphosphonium tetraphenylborate, tetra-n-butylphosphonium-o, o- Examples include phosphorus compounds such as diethylphosphorodithioate, quaternary ammonium salts, organic metal salts, and derivatives thereof. These may be used alone or in combination. Among these curing accelerators, tertiary amines, imidazoles, and phosphorus compounds are preferably used. Among them, the degree of coloring is small,
In order to obtain a transparent and tough cured product, it is particularly preferable to use a phosphorus compound.

The content of the curing accelerator is preferably 0.01 to 8.0% by weight, more preferably 0.1 to 3.0% by weight, based on the epoxy resin. If the content of the curing accelerator is less than 0.01% by weight,
It may not be possible to obtain a sufficient curing acceleration effect,
If it exceeds 8.0% by weight, discoloration may be observed in the obtained cured product.

Examples of the above-mentioned deterioration inhibitor include conventionally known deterioration inhibitors such as phenol compounds, amine compounds, organic sulfur compounds and phosphine compounds. Examples of the modifier include conventionally known modifiers such as glycols, silicones, and alcohols. Examples of the silane coupling agent include, for example, conventionally known silane coupling agents such as a silane coupling agent and a titanate coupling agent. Examples of the defoaming agent include a conventionally known defoaming agent such as a silicone type.

In the present invention, these components (hereinafter referred to as resin components) other than the glass powder described in detail below,
That is, the Abbe number of the cured product obtained by curing the epoxy resin, the curing agent, and the additives to be blended if necessary is, for example, 20 to 65, preferably 25 to 60, and sodium D The refractive index (n _D ) at the line is
It is preferably from 1.40 to 1.65, more preferably from 1.45 to 1.60.

As a preferable combination of an epoxy resin and a curing agent for obtaining such Abbe number and refractive index, for example, the epoxy resin is a bisphenol A type epoxy resin and triglycidyl isocyanurate, and the curing agent is an acid anhydride. And a combination in which the epoxy resin is a bisphenol A type epoxy resin and a novolak type epoxy resin, and the curing agent is a phenolic curing agent.

Examples of the glass powder include SiO ₂ or those containing SiO ₂ and B ₂ O ₃ as main components. In order to adjust the Abbe number of the glass powder, zinc, titanium, cerium, bismuth, It is preferable that one or more components selected from lead and selenium are appropriately blended. Particularly, in order to make the Abbe number of the glass powder close to the Abbe number of the cured product obtained by curing the resin component, it is preferable that zinc and titanium are blended.
When zinc is blended, it is usually blended as ZnO, and its content is preferably 1 to 10% by weight based on the glass powder. When titanium is blended, it is usually blended as TiO ₂ , and its content is preferably 1 to 10% by weight based on the glass powder.

In order to adjust the refractive index of the glass powder, Na ₂ O, Al ₂ O ₃ , CaO,
It is preferable that BaO or the like is appropriately blended.

The glass powder can be obtained, for example, by melting each of the above-mentioned raw materials and quenching the obtained glass frit using a ball mill or the like. The obtained ground glass powder may be used as it is, but, for example, it is preferable to use a spherical glass powder whose surface has been framed to be spherical.
Since spherical glass powder has no bubbles or cracks on the surface,
Light scattering at the interface between the resin component and the glass powder is small, and the light transmittance of the obtained cured product can be improved. In addition, it is preferable that the obtained glass powder is obtained as a glass powder having a predetermined particle size by, for example, a sieve. Considering moldability such as gate clogging at the time, the average particle diameter is preferably 5 to 100 μm. In addition, considering the reduction of the coefficient of linear expansion and the transparency and moldability, the content of the glass powder is 10% with respect to the total amount of the epoxy resin composition for encapsulating an optical semiconductor element.
It is preferably about 90% by weight.

In the epoxy resin composition for encapsulating an optical semiconductor element of the present invention, the difference between the Abbe number of the cured resin component and the Abbe number of the glass powder is 5.0 or less. Preferably, it is 3.0 or less.

The Abbe number refers to a so-called inverse dispersion power. In the present invention, the Abbe number is
It is represented by the following equation (2).

Abbe number = ([refractive index at 589.3 nm] -1) / ([refractive index at 450 nm]-[refractive index at 650 nm]) (2) of the above cured resin component If the difference between the Abbe number and the Abbe number of the glass powder exceeds 5.0, good light transmittance at each wavelength cannot be obtained. In addition, the Abbe number of the cured body of the resin component and the Abbe number of the glass powder may be larger or smaller.

Further, in the epoxy resin composition for encapsulating an optical semiconductor element of the present invention, the relationship between the refractive index of the above-mentioned cured resin component and the refractive index of the above glass powder satisfies the following expression (1). It is preferable that the relationship is satisfied.

-0.005 ≦ n ₂ −n ₁ ≦ 0.005 (1) n ₁ : wavelength 58 of the cured product obtained by curing the resin component
Refractive index at 9.3 nm n ₂ : Refractive index at a wavelength of 589.3 nm of glass powder The relationship between the refractive index of the cured product of the above resin component and the refractive index of the above glass powder satisfies the above formula (1). If so, the light transmittance at each wavelength can be improved.

The relationship between the refractive index of the cured resin component and the refractive index of the glass powder is expressed by the following equation (3).
Is more preferably satisfied.

−0.003 ≦ n ₂ −n ₁ ≦ 0.003 (3) n ₁ and n ₂ are the same as in the above formula (1).

As described above, in order to make the Abbe number and the refractive index of the above-mentioned cured body of the resin component and the above-mentioned glass powder into the above-mentioned relationship, for example, the Abbe number and the cured body of the resin component are obtained. A method of adjusting the refractive index (for example, selection of the type of epoxy resin, use of two or more epoxy resins, selection of the type of hardener, use of two or more types of hardener, etc.), Abbe number and refraction of glass powder A method of adjusting the ratio (for example, selection of the raw material composition, adjustment of the mixing ratio, etc.) and a method of using these two methods in combination are exemplified.
Normally, the Abbe number and the refractive index of the glass powder are, to some extent, close to those of the cured body of the resin component, and then the Abbe number and the refractive index of the cured body of the resin component are further adjusted so that the cured body of the resin component and The difference between the Abbe number and the refractive index of the glass powder is adjusted to be smaller.

More specifically, for example, in the above-mentioned resin component, the epoxy resin is a bisphenol A type epoxy resin and triglycidyl isocyanurate, and the curing agent is an acid anhydride. In the case of a combination that is a system curing agent, the composition of the glass powder is changed to SiO ₂ —B ₂ O
As _{3 -ZnO-Al 2 O 3 -CaO} , in its composition, each component, SiO ₂ is 45 to 55 wt%, B ₂ O
₃ is 10 to 25% by weight, ZnO is 1 to 6% by weight, Al ₂
It is preferable to adjust so that O ₃ is blended at 10 to 18% by weight and CaO is blended at 7 to 20% by weight.

When the epoxy resin is a combination of a bisphenol A epoxy resin and a novolak epoxy resin and the curing agent is a phenolic curing agent,
The composition of the glass powder is SiO ₂ —B ₂ O ₃ —TiO ₂ —
Al ₂ O ₃ —CaO—BaO or SiO ₂ —T
In the composition of iO ₂ —Al ₂ O ₃ —CaO—BaO, each component was composed of 40 to 55% by weight of SiO ₂ ,
₂ O ₃ is 0-2 wt%, TiO ₂ is 1-7 wt%, Al
It is preferable to adjust so that the content of ₂ O ₃ is 12 to 17% by weight, the content of CaO is 25 to 35% by weight, and the content of BaO is 5 to 10% by weight.

The epoxy resin composition for encapsulating an optical semiconductor element of the present invention can be obtained, for example, in the form of a liquid, a powder, or a tablet by compressing the powder by manufacturing as follows. Can be. That is,
In order to obtain a liquid epoxy resin composition for encapsulating a photosemiconductor element, for example, each of the above-described components, that is, an epoxy resin, a curing agent, a glass powder, and, if necessary, an additive to be added, if appropriate, Good. Further, in order to obtain a powder form, or a tablet form obtained by compressing the powder, for example, the above components are appropriately blended, premixed, kneaded using a kneader, melt-mixed, and then After cooling this to room temperature, it may be pulverized by a known means and tableted if necessary.

The thus obtained epoxy resin composition for encapsulating an optical semiconductor device of the present invention is used for encapsulating optical semiconductor devices such as LEDs and CCDs. That is,
The optical semiconductor element is encapsulated by using the epoxy resin composition for encapsulating an optical semiconductor element of the present invention, without any particular limitation, by a known molding method such as ordinary transfer molding or casting. be able to. When the epoxy resin composition for encapsulating an optical semiconductor element of the present invention is in a liquid state, at least the epoxy resin and the curing agent are stored separately and mixed immediately before use, so-called two-liquid type. It may be used. When the epoxy resin composition for encapsulating an optical semiconductor element of the present invention is in the form of a powder or a tablet, the above-mentioned components are melt-mixed and set as a B-stage, which is heated during use. What is necessary is just to melt.

When the optical semiconductor element is sealed with the epoxy resin composition for encapsulating an optical semiconductor element of the present invention,
The internal stress is small, deterioration of the optical semiconductor element can be effectively prevented, and good light transmittance can be obtained at all wavelengths. Therefore, the optical semiconductor device of the present invention in which the optical semiconductor device is encapsulated by the epoxy resin composition for encapsulating an optical semiconductor device of the present invention has excellent reliability and transparency, and the fluctuation of the light transmittance at each wavelength is improved. With few, the function can be fully exhibited.

[0041]

EXAMPLES The epoxy resin compositions for encapsulating optical semiconductor elements of Examples 1 to 8 and Comparative Examples 1 to 4 were prepared by mixing the components shown in Table 1 in the proportions (parts by weight) shown in Table 1. Prepared.

[0042]

[Table 1]

The notations in Table 1 are as follows.

Bisphenol A type epoxy resin A: Epoxy equivalent 475 Bisphenol A type epoxy resin B: Epoxy equivalent 65
0 Novolak epoxy resin: Epoxy equivalent 195 Acid anhydride curing agent: Mixture of 4-methylhexahydrophthalic anhydride and hexahydrophthalic anhydride Phenol novolak resin curing agent: Hydroxyl equivalent 105 Glass powder A: SiO ₂ -B ₂ O ₃ -ZnO-Al ₂ O
A spherical glass powder having a composition of _3- CaO and obtained by flame treatment (SiO ₂ 50.0% by weight, B ₂ O ₃ 10.0% by weight,
1.0% by weight of ZnO, 10.0% by weight of Al ₂ O ₃ , Ca
O19.0% by weight) Glass powder B: SiO ₂ —B ₂ O ₃ —Al ₂ O ₃ —Ca
Spherical glass powder having a composition of O and obtained by flame treatment (SiO ₂ 52.0% by weight, B ₂ O ₃ 13.0% by weight,
Al ₂ O ₃ 17.0 wt%, CaO18.0 wt%) Glass powder _{C: SiO 2 -B 2 O 3} -Al 2 O 3 -Ca
Spherical glass powder having a composition of O and obtained by flame treatment (SiO ₂ 54.0% by weight, B ₂ O ₃ 20.0% by weight,
Al ₂ O ₃ 13.0 wt%, CaO13.0 wt%) Glass powder _{D: SiO 2 -B 2 O 3} -ZnO-Al 2 O
Ground glass powder having a composition of _3- CaO and not subjected to flame treatment (SiO ₂ 50.0% by weight, B ₂ O ₃ 10.0% by weight,
1.0% by weight of ZnO, 10.0% by weight of Al ₂ O ₃ , Ca
O 19.0% by weight) Glass powder E: SiO ₂ —TiO ₂ —Al ₂ O ₃ —Ca
Ground glass powder having a composition of O—BaO and not subjected to flame treatment (SiO ₂ 43.0% by weight, TiO ₂ 7.0% by weight, A
l ₂ O ₃ 15.0% by weight, CaO 30% by weight, BaO5
Next, using the epoxy resin compositions for encapsulating optical semiconductor elements obtained in Examples 1 to 8 and Comparative Examples 1 to 4, an LED was prepared.
Is sealed by transfer molding (150 ° C. × 3 minutes), and further cured at 150 ° C. for 3 hours.
An optical semiconductor device was manufactured. And one cycle is -2
Under a thermal cycle condition of 5 ° C. × 30 minutes / 125 ° C. × 30 minutes, the wire open rate (defective rate%) after 200 cycles was examined. The number of samples (the number n) of each optical semiconductor device was 24.

Further, the respective components of Examples 1 to 8 and Comparative Examples 1 to 4 in Table 1 were blended except for the glass powder to prepare an epoxy resin composition, which was then subjected to transfer molding (150 ° C. × 3 minutes). ) And then at 150 ° C
For 3 hours to prepare a cured product obtained by curing components other than the glass powder.

The Abbe number, refractive index, light transmittance and linear expansion coefficient of each optical semiconductor device and each cured product were measured.

Abbe number: 450 nm, 589.3 nm, Abbe refractometer T2 manufactured by Atago Co., Ltd.
The refractive index at 650 nm was measured and calculated from the above equation (2).

Refractive index: The refractive index at a wavelength of 589.3 nm was measured using an Abbe refractometer T2 manufactured by Atago Co., Ltd.

Light transmittance: Spectrophotometer UV, manufactured by Shimadzu Corporation
Using 3101, sample thickness 1 mm, wavelength 450n
m, 589.3 nm, and light transmittance at 650 nm.

Linear expansion coefficient: The coefficient of linear expansion (α ₁ ) at a temperature lower than the glass transition point was measured by a thermal analyzer (TMA) at a rate of 2 ° C./min.

The results are summarized in Table 2.

[0052]

[Table 2]

As is clear from Table 2, Examples 1 to 8
Since the difference in Abbe number is smaller than 5.0, it can be seen that the variation in light transmittance with wavelength is smaller than in Comparative Examples 1 to 4 in which the difference in Abbe number is larger than 5.0.

Further, although the difference in Abbe number between Examples 5 and 7 is almost the same, the difference in refractive index (n _{2 in the} equation (1))
Example 5 in which −n ₁ ) is in the range of −0.005 or more and 0.005 or less, corresponds to Example 7 in which the difference in refractive index (n ₂ −n _{1 in the} formula (1)) is smaller than −0.005. In comparison, it can be seen that the light transmittance is high at any wavelength.

Although the difference in Abbe number between Examples 3 and 6 is almost the same, Example 3 in which spherical glass powder is blended is different from Example 6 in which crushed glass powder is blended. In comparison, it can be seen that the light transmittance is improved.

Also, by blending glass powder,
Since the coefficient of linear expansion is reduced and the internal stress is reduced,
It can be seen that Examples 1 to 8 in which the glass powder is blended have a lower open defect rate than Comparative Example 1 in which the glass powder is not blended.

[0057]

According to the present invention, when the optical semiconductor element is encapsulated with the epoxy resin composition for encapsulating an optical semiconductor element of the present invention, the internal stress is small, so that the deterioration of the optical semiconductor element can be effectively prevented. Good light transmittance can be obtained at all wavelengths.

Therefore, the optical semiconductor device of the present invention, in which the optical semiconductor device is encapsulated by the epoxy resin composition for encapsulating an optical semiconductor device of the present invention, is excellent in reliability and transparency, and transmits light at each wavelength. The fluctuation of the rate is small, and the function can be sufficiently exhibited.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01L 33/00 F term (Reference) 4J002 CC032 CD011 CD021 CD051 CD061 CD111 CD131 CD141 DL007 EL136 FD030 FD090 FD140 FD142 FD146 FD150 FD160 FD200 GJ02 GQ05 4M109 EA02 EB02 EB03 EB04 EB06 EB08 EB09 EB12 EB16 EC04 EC11 EC15 GA01 5F041 AA25 AA40 AA43 AA44 DA44 DA47 DA58 5F088 BA10 JA06 JA20

Claims (4)

[Claims] An epoxy resin composition for encapsulating an optical semiconductor element, comprising an epoxy resin, a curing agent and glass powder, wherein a component other than the glass powder of the epoxy resin composition for encapsulating an optical semiconductor element is cured. Wherein the difference between the Abbe number of the cured product obtained by the above method and the Abbe number of the glass powder is 5.0 or less. 2. An epoxy resin composition for encapsulating an optical semiconductor element comprising an epoxy resin, a curing agent and glass powder, wherein a component other than the glass powder of the epoxy resin composition for encapsulating an optical semiconductor element is cured. The difference between the Abbe number of the cured product obtained by the above method and the Abbe number of the glass powder is 5.0 or less, and the epoxy resin composition for encapsulating an optical semiconductor element other than the glass powder. An epoxy resin composition for encapsulating an optical semiconductor element, wherein the relationship between the refractive index of a cured product obtained by curing the components and the refractive index of the glass powder is represented by the following formula (1). −0.005 ≦ n ₂ −n ₁ ≦ 0.005 (1) n ₁ : refractive index at a wavelength of 589.3 nm of a cured product obtained by curing a component other than the glass powder n ₂ : the above glass Refractive index of powder at a wavelength of 589.3 nm 3. The epoxy resin composition according to claim 1, wherein the glass powder is a spherical glass powder. 4. An optical semiconductor element obtained by encapsulating an optical semiconductor element using the epoxy resin composition for encapsulating an optical semiconductor element according to claim 1.
Optical semiconductor device.