JP2760889B2 - Optical semiconductor device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical semiconductor device resin-sealed with a sealing resin excellent in both light transmittance and low stress.

[Prior Art] A resin composition used for sealing an optical semiconductor element such as an LED (light emitting diode) is required to be transparent, and is generally a bisphenol A type epoxy resin, an alicyclic epoxy resin. An epoxy resin composition comprising an epoxy resin such as a resin and an acid anhydride-based curing agent is used.

However, when the epoxy resin composition is used as a sealing resin, curing shrinkage during curing of the epoxy resin composition,
Or, an internal stress is generated due to a strain caused by a difference in linear expansion coefficient between the epoxy resin and the optical semiconductor element, and the optical semiconductor element is deteriorated due to the internal stress. The problem of lowering occurs. In order to solve such a problem, conventionally, as a method of reducing the internal stress, a method has been proposed in which an epoxy resin is modified with an organopolysiloxane to reduce the elastic modulus of a cured epoxy resin composition. Running in the department.

[Problems to be solved by the invention]

However, even if the above method can reduce the internal stress, the obtained epoxy resin composition cured product has a non-uniform structure, and the light transmittance of the sealing resin is significantly reduced. Has a fatal drawback.

The present invention has been made in view of such circumstances,
The present invention relates to an optical semiconductor device having small internal stress and excellent light transmittance.

[Means for solving the problem]

In order to achieve the above object, the optical semiconductor device of the present invention has a configuration in which an optical semiconductor element is sealed using an epoxy resin composition containing the following components (A) to (D).

(A) Transparent epoxy resin.

(B) an acid anhydride-based curing agent;

(C) a curing catalyst.

(D) An organopolysiloxane having a difference in refractive index at room temperature from a cured product comprising the components (A), (B) and (C) within a range of ± 0.01.

[Action]

That is, the present inventors have repeated a series of studies to obtain a sealing resin having small internal stress and excellent optical transparency. In the course of that research, the conventional organopolysiloxane reduced the internal stress but reduced the light transmittance because the difference between the refractive index of the cured epoxy resin composition and the refractive index of the organopolysiloxane. I recalled that it might be because it was big. Further studies were conducted to reduce the difference between the two refractive indices. As a result, they have found that a transparent and low internal stress sealing resin can be obtained by using an organopolysiloxane having a small difference from the refractive index of the cured epoxy resin composition, and reached the present invention.

The epoxy resin composition used in the present invention comprises a transparent epoxy resin (component A) and an acid anhydride-based curing agent (component B).
And a curing catalyst (component (C)) and a specific organopolysiloxane (component (D)), and are usually in the form of a liquid, a powder, or a tablet obtained by compressing the powder.

As the transparent epoxy resin (component A), a bisphenol-type epoxy resin and an alicyclic epoxy resin are preferable because they have transparency, but other epoxy resins that are usually used may be used in some cases. When the other epoxy resin is used, the use ratio is usually set to 5 to 100 parts by weight of the other epoxy resin with respect to 100 parts by weight of the transparent epoxy resin (hereinafter abbreviated as “part”). It is preferred to do so. As such an epoxy resin, an epoxy resin having an epoxy equivalent of 100 to 1000 and a softening point of 120 ° C. or lower is generally used. In addition, the transparency of the transparent epoxy resin includes the case where the transparent epoxy resin is colored and transparent, and means that the light transmittance at a wavelength of 600 mm is 80 to 100% at a thickness of 1 mm.

The acid anhydride-based curing agent (component B) has a molecular weight of 14
Those having about 0 to 200 are preferably used, and examples thereof include colorless to pale yellow acid anhydrides such as hexahydrophthalic anhydride, tetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, and methyltetrahydrophthalic anhydride. The compounding amount of the acid anhydride-based curing agent is epoxy resin 10
It is preferable to set the range of 50 to 200 parts with respect to 0 part.

Examples of the curing catalyst (component C) include tertiary amines, imidazole compounds, and organometallic complex salts.

As the specific organopolysiloxane (component D), there is a cured epoxy resin composition comprising the transparent epoxy resin (component A), an acid anhydride-based curing agent (component B), and a curing catalyst (component C). Difference of refractive index is ± 0.01 at room temperature
Must be used. The refractive index is a value measured using an Atsube refractometer.

Further, among the above specific organopolysiloxanes, it is particularly preferable to use those represented by the above general formula (I).

In the above general formula (I), it is preferable to use those having m + n = 30 to 90. Further, the number of phenyl groups is preferably 30 to 140 in one molecule. Further, among the organopolysiloxanes represented by the above general formula (I), it is particularly preferable to use methylphenyl polysiloxane, diphenyl polysiloxane and the like. Such an organopolysiloxane has a number average molecular weight of 4500 to 13000.
Are preferred.

The above specific organopolysiloxane (D component)
Is preferably set in the range of 5 to 100 parts with respect to 100 parts of the epoxy resin. That is, when the organopolysiloxane content is less than 5 parts, the elastic modulus of the cured product is not sufficiently reduced, and when it is more than 100 parts, the elastic modulus is reduced but the coefficient of linear expansion becomes too large, and as a result, a sufficient low stress effect is obtained. This is because there is a tendency that it becomes impossible to obtain.

The epoxy resin composition used in the present invention includes the above A to
In addition to the component D, conventionally known additives such as a dye, a denaturant, a discoloration inhibitor, an antioxidant, a release agent, and a reactive or non-reactive diluent can be appropriately compounded as required.

The epoxy resin composition used in the present invention can be produced, for example, as follows. That is, after appropriately mixing and preliminarily mixing the above-mentioned respective component raw materials, the mixture is kneaded in a kneading machine and melt-mixed. After cooling to room temperature, it can be manufactured by a series of steps of pulverizing by a known means and tableting as required. Prior to the mixing of the above-mentioned components, the transparent epoxy resin (component A) and the specific organopolysiloxane (component D) are uniformly dissolved in an organic solvent such as xylene beforehand.
A modified transparent epoxy resin is prepared by heat-treating at 130 ° C. for about 5 hours and pre-reacting. Then, after the remaining acid anhydride-based curing agent (component B), curing catalyst (component C) and a conventionally known additive are blended in the above-mentioned modified epoxy resin composition in a predetermined ratio, the same production method as described above is followed. It can also be manufactured. As described above, it is preferable from the viewpoint of the effect that the transparent epoxy resin (component A) and the specific organopolysiloxane (component D) are reacted in advance to preliminarily modify the transparent epoxy resin. Further, when the epoxy resin composition is a liquid, it is only necessary to mix the above components.

The sealing of the optical semiconductor element using such an epoxy resin composition is not particularly limited, and can be performed by a known molding method such as ordinary transfer molding and casting.

The optical semiconductor device obtained in this manner has excellent transparency, extremely low internal stress, and high reliability.
This is because, by using a specific organopolysiloxane, the epoxy resin is modified and the low stress property is improved,
Moreover, it is considered that the difference between the refractive index of the cured resin component and the refractive index of the specific organopolysiloxane is very small.

〔The invention's effect〕

As described above, the optical semiconductor device of the present invention uses an organopolysiloxane having a small difference between the refractive index of the cured epoxy resin composition and the refractive index of itself, and uses the epoxy resin composition containing the same. It is obtained by sealing a semiconductor element with a resin. For this reason, this sealing resin is excellent in light transmittance, and its internal stress is small. For example, in a light emitting element, for example, in a light emitting element, suppression of luminance degradation is effectively performed, and reliability is extremely increased.

 Next, examples will be described together with comparative examples.

Example 1 73 parts of a bisphenol A type epoxy resin (liquid resin) having an epoxy equivalent of 185, and 27 parts of an alicyclic epoxy resin (liquid resin) represented by the following structural formula having an epoxy equivalent of 252, A modified epoxy resin is obtained by adding 22 parts of amino-modified methylphenylpolysiloxane having a number average molecular weight of 11,000 and a refractive index of 1.531 at both ends with amino-modified methylphenylpolysiloxane, heat-treating it at about 130 ° C. for 5 hours in xylene, and then de-xylene. Was. Next, a mixture obtained by adding and mixing 100 parts of 4-methylhexahydrophthalic anhydride and 0.4 part of 2-ethyl-4-methylimidazole to 122 parts of the modified epoxy resin was heat-cured at 120 ° C. to obtain a cured epoxy resin composition. I got The light transmittance of this cured product was as high as 80% at a thickness of 4 mm.

In the above formulation, when the epoxy resin is not modified with amino-modified methylphenylpolysiloxane at both ends, that is, 73 parts of bisphenol A modified epoxy resin having an epoxy equivalent of 185, 27 parts of an alicyclic epoxy resin having an epoxy equivalent of 252. The epoxy resin composition cured product obtained by adding and mixing 100 parts of 4-methylhexahydrophthalic anhydride and 0.4 part of 2-ethyl-4-methylimidazole at 120 ° C. has a refractive index of 1.531, It is equal to the refractive index of the amino-modified methylphenylpolysiloxane at both ends.

Example 2 62 parts of a bisphenol A type epoxy resin (liquid resin) having an epoxy equivalent of 185, and 38 parts of an alicyclic epoxy resin (liquid resin) represented by the following structural formula having an epoxy equivalent of 252, A modified epoxy resin was obtained by adding 22 parts of an amino-modified methylphenylpolysiloxane having a number average molecular weight of 8000 and a refractive index of 1.527 at both ends with amino-modified methyl phenylpolysiloxane, heat-treating these in xylene at about 130 ° C. for 5 hours, and then removing the xylene. . Next, a mixture obtained by adding and mixing 100 parts of 4-methylhexahydrophthalic anhydride and 0.42 part of 2-ethyl-4-methylimidazole to 122 parts of the modified epoxy resin was heat-cured at 120 ° C. to obtain a cured epoxy resin composition. I got The light transmittance of this cured product was as high as 88% at a thickness of 4 mm.

In the above formulation, when the epoxy resin is not modified with amino-modified methylphenylpolysiloxane at both ends, that is, 62 parts of a bisphenol A type epoxy resin having an epoxy equivalent of 185, and 38 parts of an alicyclic epoxy resin having an epoxy equivalent of 252. The refractive index of a cured epoxy resin composition obtained by heat-curing a mixture of 100 parts of 4-methylhexahydrophthalic anhydride and 0.4 part of 2-ethyl-4-methylimidazole at 120 ° C. is 1.527, It is equal to the refractive index of the amino-modified methylphenylpolysiloxane at both ends.

Example 3 The amount of the amino-modified methylphenylpolysiloxane at both ends was changed to 5 parts, and the amount of the modified epoxy resin was changed to 105 parts. Otherwise in the same manner as in Example 1, a cured product of the epoxy resin composition was obtained. The light transmittance of this cured product was as high as 86% at a thickness of 4 mm.

In the above composition, when the epoxy resin is not modified with both terminal amino-modified methylphenylpolysiloxane, that is, 73 parts of a bisphenol A type epoxy resin having an epoxy equivalent of 185 and 27 parts of an alicyclic epoxy resin having an epoxy equivalent of 252. The epoxy resin composition cured product obtained by adding and mixing 100 parts of 4-methylhexahydrophthalic anhydride and 0.4 part of 2-ethyl-4-methylimidazole at 120 ° C. has a refractive index of 1.531, It is equal to the refractive index of the amino-modified methylphenylpolysiloxane at both ends.

Example 4 The amount of amino-modified methylphenylpolysiloxane at both ends was changed to 100 parts, and the amount of modified epoxy resin was changed to 200 parts. Otherwise, the procedure of Example 2 was repeated to obtain a cured epoxy resin composition. The light transmittance of this cured product was as high as 80% at a thickness of 4 mm.

Example 5 As an organopolysiloxane, the following general formula (II)
An organopolysiloxane having a number average molecular weight of 6000 and a refractive index of 1.531 was used. Otherwise in the same manner as in Example 1, a cured product of the epoxy resin composition was obtained. The light transmittance of this cured product was as high as 82% at a thickness of 4 mm.

In the above formulation, when the epoxy resin is not modified with the organopolysiloxane represented by the general formula (II), that is, 73 parts of a bisphenol A type epoxy resin having an epoxy equivalent of 185 and an alicyclic compound having an epoxy equivalent of 252 27 parts of epoxy resin, 4-methylhexahydrophthalic anhydride 10
A cured product of an epoxy resin composition obtained by thermally curing at 120 ° C. a mixture obtained by adding and mixing 0 part and 0.4 part of 2-ethyl-4-methylimidazole has a refractive index of 1.531 and is represented by the general formula (II). It is equal to the refractive index of the organopolysiloxane.

[Example 6] Using the same amount of the components of Example 1 but without preparing a modified epoxy resin in advance, the components were mixed and mixed, kneaded in a kneader and melt-mixed. This was thermally cured at 120 ° C. to obtain a cured epoxy resin composition. The light transmittance of this cured product was as high as 80% at a thickness of 4 mm.

Incidentally, in the above formulation, when not using amino-modified methylphenylpolysiloxane at both ends, 73 parts of bisphenol A type epoxy resin having an epoxy equivalent of 185, 27 parts of an alicyclic epoxy resin having an epoxy equivalent of 252,
The epoxy resin composition cured product obtained by adding and mixing 100 parts of 4-methylhexahydrophthalic anhydride and 0.4 part of 2-ethyl-4-methylimidazole at 120 ° C. has a refractive index of 1.531. It is equal to the refractive index of the terminal amino-modified methylphenylpolysiloxane.

[Comparative Example 1] 100 parts of a bisphenol A type epoxy resin (liquid resin) having an epoxy equivalent of 185 had a number average molecular weight of 8000 and a refractive index of 1.5.
27 Both ends amino-modified methylphenyl polysiloxane 22
Then, after heat-treating these in xylene at about 130 ° C. for 5 hours, dexylene was obtained to obtain a modified epoxy resin. Next, in the modified epoxy resin 122 parts,
A mixture of 100 parts of 4-methylhexahydrophthalic anhydride and 0.42 parts of 2-ethyl-4-methylimidazole was heat-cured at 120 ° C. to obtain a cured epoxy resin composition. The light transmittance of this cured product was 9% at a thickness of 4 mm, and the appearance was cloudy.

The light transmittance of the cured product was low because the epoxy resin was not modified with amino-modified methylphenylpolysiloxane at both ends in the mixture.
That is, 100 parts of a bisphenol A type epoxy resin having an epoxy equivalent of 185, 4-methylhexahydrophthalic anhydride 1
00 parts, a mixture of 0.42 parts of 2-ethyl-4-methylimidazole was heat-cured at 120 ° C., and the cured product of the epoxy resin composition had a refractive index of 1.541. This is because the difference was 0.01 or more as compared with the refractive index of 1.527.

[Comparative Example 2] 100 parts of 4-methylhexahydrophthalic anhydride and 0.42 part of 2-ethyl-4-methylimidazole were added to 100 parts of bisphenol A type epoxy resin (liquid resin) and mixed without using organopolysiloxane. Thus, an epoxy resin composition was obtained.

Next, using the epoxy resin compositions obtained in Examples 1 to 5 and Comparative Example 2, a light-emitting diode was resin-molded by casting to produce an optical semiconductor device. Then, the current-carrying luminance degradation of this optical semiconductor device was measured. The results are shown in the table below. The method for measuring the current-carrying luminance degradation is as follows:
I went as follows. That is, a constant current was applied to the optical semiconductor device (LED device), and as a luminance, an output current value of the light receiving element after 5 seconds from the current application was obtained, and the deterioration rate was measured.

Package: Pilot lamp with a diameter of 5mm.

Evaluation element: GaAs, 0.5 mm x 0.5 mm.

Evaluation conditions: The luminance degradation rate was measured after 1000 hours of 20 mA conduction at −30 ° C.

From the results in the above table, it can be seen that the luminance of the example product is suppressed as compared with the comparative example product, and the low stress property as well as the light transmittance is improved.

Claims (7)

(57) [Claims] An optical semiconductor device comprising an optical semiconductor element encapsulated with an epoxy resin composition containing the following components (A) to (D). (A) Transparent epoxy resin. (B) an acid anhydride-based curing agent; (C) a curing catalyst. (D) An organopolysiloxane having a difference in refractive index at room temperature from a cured product comprising the components (A), (B) and (C) within a range of ± 0.01. 2. The optical semiconductor device according to claim 1, wherein the organopolysiloxane as the component (D) is represented by the following general formula (I). 3. The optical semiconductor device according to claim 1, wherein the transparent epoxy resin as the component (A) is modified in advance with the organopolysiloxane as the component (D). 4. The optical semiconductor device according to claim 1, wherein the transparent epoxy resin is at least one of a bisphenol-type epoxy resin and an alicyclic epoxy resin. 5. The method according to claim 1, wherein the amount of the organopolysiloxane is set in a range of 5 to 100 parts by weight based on 100 parts by weight of the transparent epoxy resin. The optical semiconductor device according to the above. 6. An epoxy resin composition for encapsulating an optical semiconductor, comprising the following components (A) to (D). (A) Transparent epoxy resin. (B) an acid anhydride-based curing agent; (C) a curing catalyst. (D) An organopolysiloxane having a difference in refractive index at room temperature from a cured product comprising the components (A), (B) and (C) within a range of ± 0.01. 7. The epoxy resin composition for optical semiconductor encapsulation according to claim 6, wherein the organopolysiloxane of the component (D) is represented by the following general formula (I).