JPH03224255A - Optical semiconductor device - Google Patents

Abstract

PURPOSE:To improve optical transmittance of a semiconductor device and reduce the internal stress, by sealing an optical semiconductor element by using special epoxy resin composition which contains transparent epoxy resin and specified organopolysiloxane. CONSTITUTION:An optical semiconductor element is sealed with the following; material which contains transparent epoxy resin (component A) like bisphenol A-type epoxy resin, organopolysiloxane (component B) which has at least one amino group in a molecule and whose molecular weight is 500-7000, acide anhydride system harder (component C) like hexahydro phthalic anhydride, and a curing catalyst (component D) like tertiary amine imidazole compound, or epoxy resin composition containing transparent epoxy resin (component A') which is previously denatured by the above organopolysiloxane, and components C and D. The above material is turned into transparent sealing resin with a low modulus of elasticity and low stress by curing.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an optical semiconductor device sealed with a sealing resin having excellent light transmittance and low stress properties.

[Conventional technology]

As a resin composition for use in optical semiconductor devices such as light emitting diodes (LEDs), the cured product is required to have transparency, and generally contains a bisphenol A epoxy resin or an alicyclic epoxy resin, Those obtained by using an acid anhydride as a curing agent are widely used.

However, when the above-mentioned epoxy resin composition is used, internal stress is generated due to curing shrinkage during curing of this resin composition.
This causes a problem in that the brightness of the light emitting element decreases. In order to solve such problems, conventional methods for reducing the internal stress include: (1) adding a flexibility imparting agent such as rubber particles to reduce the elastic modulus of the resin composition;
(2) A method of reducing the linear expansion coefficient of the sealing resin by adding an inorganic powder such as silica powder with a small linear expansion coefficient has been proposed and has been implemented in some cases.

[Problem to be solved by the invention]

However, although the method of adding the flexibility-imparting agent described above and the inorganic powder described in It has a fatal drawback as a resin composition for use.

The present invention was made in view of the above circumstances, and an object of the present invention is to provide an optical semiconductor device with low internal stress (and excellent light transmittance).

[Means to solve the problem]

In order to achieve the above object, the first gist of the optical semiconductor device of the present invention is to seal an optical semiconductor element using an epoxy resin composition containing the following components (A) to (D). , (A) Transparent epoxy resin.

(B) Organopolysiloxane having a molecular weight of 500 to 7,000 and having at least one amino group in one molecule.

(C) Acid anhydride curing agent.

(D) Curing catalyst.

The second gist is to seal an optical semiconductor element using an epoxy resin composition containing the following components (A'), (C), and (C).

(A') A transparent epoxy resin modified with an organopolysiloxane having a molecular weight of 500 to 7,000 and having at least one amino group in one molecule.

(C) Acid anhydride curing agent.

(D) Curing catalyst.

[Effect]

In other words, the present inventors conducted a series of studies in order to obtain a sealing resin with low internal stress (and excellent optical transparency). If you use a special epoxy resin that has been modified with organopolysiloxane as the main epoxy resin, it is possible to create a resin that has a "sea" made of a resin component such as epoxy resin and an "island" made of a silicone compound. We found that a sea-island structure is formed and is effective in reducing internal stress.Then, we conducted further research focusing on the above-mentioned organopolysiloxane.As a result, we found that, in general, organopolysiloxane and epoxy resin are different from each other. Their compatibility is low, and if they are used together or if the epoxy resin is modified with organopolysiloxane, the organopolysiloxane and epoxy resin will phase separate from each other, and the organopolysiloxane and epoxy resin will phase separate from each other. Island components (domains) of siloxane are generated.As a result, the progress of light emitted from the light emitting element is blocked by the domains.
It was found that the light transmittance of the cured epoxy resin composition was significantly reduced. At the same time, it is also known that the smaller the molecular weight of the organopolysiloxane, the smaller the domain size of the organopolysiloxane, and that if the domain is small enough, the cured product will maintain good light transmittance. I figured it out. Based on this knowledge, the present inventors conducted further research and found that organopolysiloxanes having amino groups that are more reactive with epoxy groups are used in combination with the above epoxy resins or for modification of epoxy resins. It is preferable to use an organopolysiloxane having a molecular weight of 500 to 7000 from the viewpoint of the relationship with the domain, etc., and whether this organopolysiloxane and an epoxy resin are used together. The inventors have discovered that by modifying an epoxy resin with the above organopolysiloxane and curing it with an acid anhydride curing agent, a transparent, low-stress sealing resin with a low modulus of elasticity can be obtained, resulting in the present invention.

The epoxy resin composition used in this invention consists of (1) a transparent epoxy resin (component A), a specific organopolysiloxane (component B), an acid anhydride curing agent (component C), and a curing catalyst (component D). (1) A transparent epoxy resin modified with the above specific organopolysiloxane (A' acid component, an acid anhydride curing agent (C component), a curing catalyst (D component)) It is usually obtained in the form of a liquid, a powder, or a tablet made by compressing this powder.However, in order to make an epoxy resin composition into a powder or a tablet, generally, The transparent epoxy resin (component A) is modified in advance with the specific organopolysiloxane (component B).

Examples of the transparent epoxy resin (component A) include bisphenol A epoxy resins and alicyclic epoxy resins from the viewpoint of transparency of the cured product obtained. These transparent epoxy resins may be used alone or in combination.

In some cases, these modified epoxy resins may be used in combination with other commonly used epoxy resins. When using the other epoxy resins mentioned above, it is preferable that the proportion used is within 950% by weight of the total epoxy resin (hereinafter abbreviated as "%"). The epoxy resin used in this invention generally has an epoxy equivalent of 100 to 10.
00. It is preferable to use one having a softening point of 120°C or less.

Examples of the specific organopolysiloxane (component B) include organopolysiloxanes having a molecular weight of 500 to 7,000 and having at least one amino group in one molecule. As described above, when the above-mentioned specific organopolysiloxanes are used, since they have high reactivity with the epoxy groups in the epoxy resin, the modification reaction proceeds smoothly without side reactions and is effective. Examples of such specific organopolysiloxanes include dimethylpolysiloxane, methylphenylpolysiloxane, and diphenylpolysiloxane, and it is particularly preferable to use one represented by the following general formula (1). .

(The following is a blank space) H3 1 3 H3 H3 Z 4 FI3 And in the above formula (1), Hl + n = 3 to 40
It is particularly preferable to use In addition, the above general formula (
Among the organopolysiloxanes represented by 1), it is particularly preferable to use one represented by the following formula (n).

In the above formula (n), the part where the number of repeating units is m and n
The parts may be connected alternately or randomly. Or they may be combined in blocks. Moreover, as R' in the formula, - boat fishing - C) lzGHzGHz- can be mentioned. Such an organopolysiloxane contains at least one amino group in one molecule that has good reactivity with the epoxy group in the epoxy resin.
must have a molecular weight of 500 to 7000.
It is necessary that Particularly preferred is 500-3
It is 000. That is, if the molecular weight of the organopolysiloxane exceeds 7,000, layer separation will occur during modification of the epoxy resin or during curing of the epoxy resin, and this layer separation will remain, resulting in non-uniform blending in the resin composition. The silicone compound will not be uniformly dispersed. the result,
It becomes difficult to obtain the effect of reducing internal stress. Moreover, if the molecular weight is too large, the particles of the silicone compound themselves will also become too large and light will hit the particles, resulting in a decrease in light transmittance. On the other hand, if the molecular weight is less than 500, the silicone compound will dissolve in the epoxy resin and will not form a sea-island structure, so that the effect of reducing internal stress will not be obtained. Furthermore, in the above general formula (I), R3
When an organopolysiloxane in which both R4 and R4 are phenyl groups is used, the resulting cured epoxy resin composition has better transparency and is even more effective.

The amount of the organopolysiloxane used (including both when simply mixing and when modifying the transparent epoxy resin) is 5 to 40 parts by weight per 100 parts by weight (hereinafter abbreviated as "parts") of the epoxy resin. It is preferable to set it within a range. That is, if the amount of organopolysiloxane is less than 5 parts, a sufficient stress reduction effect cannot be obtained, whereas if it exceeds 40 parts, the domain of the organopolysiloxane becomes large and the sealing resin becomes opaque.

Transparent epoxy resin modified with the above organopolysiloxane (A' acid component is the above ≠ B acid component is the above A
The components are modified in advance, and the amount of the component B to be used during the modification is determined according to the above.

The acid anhydride curing agent (component C) has a molecular weight of 14
It is preferable to use about 0 to 200, such as hexahydrophthalic anhydride, tetrahydrophthalic anhydride,
Examples include colorless to pale yellow acid anhydrides such as methylhexahydrophthalic anhydride and methyltetrahydrophthalic anhydride. The blending amount of the acid anhydride curing agent is preferably set in the range of 50 to 200 parts per 100 parts of the transparent epoxy resin (component A) or modified epoxy resin (acid component A'). be.

Examples of the curing catalyst (component D) include tertiary amines, imidazole compounds, organometallic complex salts, etc., which may be used alone or in combination.

In addition to the above-mentioned raw materials, the epoxy resin composition used in this invention may optionally contain dyes, modifiers, discoloration inhibitors, anti-aging agents, mold release agents, reactive or non-reactive diluents, etc. Conventionally known additives may be appropriately blended.

The above-mentioned epoxy resin composition used in this invention is prepared by: (1) simply blending the above-mentioned organopolysiloxane (component B) and a transparent epoxy resin (component A), and (2) reacting the above-mentioned B component with the epoxy resin in advance. There are two types of modified products (A' acid component made and blended). Among these,
The above-mentioned type (2) can be produced, for example, by suitably blending the above-mentioned components and mixing them at room temperature.

This type of epoxy resin composition is usually in liquid form. In addition, type (2), for example, is made by first dissolving the transparent epoxy resin (component A) and the above-mentioned specific organopolysiloxane (component B) in an organic solvent, and then mixing and reacting at a temperature of 150°C. Modified epoxy resin (A'
Prepare the acid component. After the organic solvent is removed by volatilization, an acid anhydride curing agent, curing catalyst, and additives are blended and melted and mixed, cooled to room temperature, pulverized by known means, and pounded if necessary. It can also be manufactured by locking.

In addition, when manufacturing the epoxy resin composition of the type (■), there are no particular restrictions on the organic solvent used when reacting and modifying the transparent epoxy resin (component A) and a specific organopolysiloxane (component B) in advance. Not something to do,
For example, hydrocarbon organic solvents such as toluene and xylene, dichloromethane 1.1.1-1-lichloroethane, 1,1
．． Halogenated hydrocarbon organic solvents such as 2-trichloroethane, ether organic solvents such as diethyl ether, dioxane, and tetrahydrofuran, and acetone.

Examples include ketone organic solvents such as methyl ethyl ketone and diethyl ketone, and mixed solutions thereof. In addition, methods for removing the organic solvent in the above manufacturing method include methods for removing it at room temperature or by heating and reducing pressure as necessary, and methods for removing it by vacuum freeze-drying, but are not particularly limited. .

The encapsulation of optical semiconductor elements using such epoxy resin compositions of type 1 and 2 is not particularly limited, and can be performed by known molding methods such as ordinary transfer molding and casting. .

The optical semiconductor device thus obtained has excellent transparency, extremely low internal stress, and high reliability. This is achieved by blending an epoxy resin with a specific organopolysiloxane, or by modifying the epoxy resin with a specific organopolysiloxane, so that the organopolysiloxane, which is an island component, becomes fine in the epoxy resin, which is a sea component. This is thought to be because the sea-island structure is formed stably and uniformly.

(Effects of the Invention) As described above, in the optical semiconductor device of the present invention, the optical semiconductor element is resin-sealed using a special epoxy resin composition containing a transparent epoxy resin and a specific organopolysiloxane. Therefore, the sealing resin has excellent light transmittance, low internal stress, and suppresses brightness deterioration of the light emitting element, making it highly reliable.

Next, examples will be described together with comparative examples.

[Example 1] 100 parts of bisphenol A epoxy resin with an epoxy equivalent of 185 and a molecular weight of 1680 in an organic solvent (xylene)
A modified bisphenol A type epoxy resin was prepared by mixing 20 parts of polydimethylsiloxane modified with both amino terminals and heat-treating at 130°C, followed by volatilizing and removing the organic solvent. 100 parts of 4-methylhexahydrophthalic anhydride and 0.4 parts of 2-ethyl-4-methylimidazole are blended with 120 parts of this modified bisphenol A type epoxy resin and mixed at room temperature to achieve the desired optical semiconductor encapsulation. An epoxy resin composition was obtained.

[Example 2] A polydimethylsiloxane having a molecular weight of 3000 was used instead of a polydimethylsiloxane modified with amino at both ends and having a molecular weight of 1680. Other than that, the same procedure as in Example 1 was carried out to obtain the desired epoxy resin composition for encapsulating optical semiconductors.

[Example 3] Instead of polydimethylsiloxane modified with amino at both ends and having a molecular weight of 16,800, methylphenyl polysiloxane modified with amino at both ends (methyl group/phenyl group = 3) having a molecular weight of 6,600 was used.
/1) was used. Other than that, the same procedure as in Example 1 was carried out to obtain the desired epoxy resin composition for encapsulating optical semiconductors.

[Example 4] Polydimethylsiloxane modified with amino at both ends and having a molecular weight of 500 was used instead of polydimethylsiloxane modified with amino at both ends and having a molecular weight of 1,680. Other than that, the same procedure as in Example 1 was carried out to obtain the desired epoxy resin composition for encapsulating optical semiconductors.

[Example 5] Polydimethylsiloxane modified with amino at both ends and having a molecular weight of 7000 was used instead of polydimethylsiloxane modified with amino at both ends and having a molecular weight of 1680. Other than that, the same procedure as in Example 1 was carried out to obtain the desired epoxy resin composition for encapsulating optical semiconductors.

[Example 6] Bisphenol A epoxy resin 10 used in Example 1
0 parts to 100 parts of 4-methylhexahydrophthalic anhydride,
0.4 parts of 2-ethyl-4-methylimidazole and 20 parts of both terminal amino-modified polydimethylsiloxane having a molecular weight of 1680 were blended and mixed at room temperature to obtain the desired epoxy resin composition for encapsulating optical semiconductors. Ta.

[Example 7] Polydimethylsiloxane modified with amino at both ends and having a molecular weight of 3000 was used instead of polydimethylsiloxane modified with amino at both ends and having a molecular weight of 1680. Other than that, the same procedure as in Example 6 was carried out to obtain the desired epoxy resin composition for encapsulating optical semiconductors.

[Example 8] Instead of polydimethylsiloxane modified with amino at both ends and having a molecular weight of 1680, methylphenyl polysiloxane modified with amino at both ends and having a molecular weight of 6600 (methyl group/phenyl group = 3) was used.
/1) was used. Other than that, the same procedure as in Example 6 was carried out to obtain the desired epoxy resin composition for encapsulating optical semiconductors.

[Example 9] Polydimethylsiloxane modified with amino at both ends and having a molecular weight of 500 was used instead of polydimethylsiloxane modified with amino at both ends and having a molecular weight of 1,680. Other than that, the same procedure as in Example 6 was carried out to obtain the desired epoxy resin composition for encapsulating optical semiconductors.

[Example 10] A polydimethylsiloxane modified with amino at both ends and a molecular weight of 7,000 was used instead of a polydimethylsiloxane modified with amino at both ends and a molecular weight of 1,680. Other than that, the same procedure as in Example 6 was carried out to obtain the desired epoxy resin composition for encapsulating optical semiconductors.

[Comparative example]

No organopolysiloxane was used. Other than that, the same procedure as in Example 6 was carried out to obtain the desired epoxy resin composition for encapsulating optical semiconductors.

Using each of the epoxy resin compositions of Examples 1 to 10 and Comparative Examples obtained as described above, this was cured at 120°C to produce a cured product, and a transparent cured product was able to be obtained. . The light transmittance and flexural modulus of this cured product are shown in the table below. Note that the above light transmittance and flexural modulus were measured as follows.

(Light transmittance) Prepare a cured product with a thickness of 1 cm, and measure wavelength 60 using a spectrophotometer.
The transmittance of 0ni+ was measured.

(Bending elastic modulus) A cured product having a thickness of 4++ mm, a width of 10 mm, and a length of 80 mm was prepared, and measured by a three-point bending test method with a distance between fulcrums of 64 mm.

From the above results, the cured product of the example has a light transmittance that is almost the same as that of the cured product of the comparative example to which no silicone compound is added, and the flexural modulus is higher than that of the cured product of the comparative example. It's lower than things. This shows that the epoxy resin compositions obtained in Examples are excellent in light transmittance and low stress properties. Further, an optical semiconductor device was manufactured by resin-sealing an optical semiconductor element by casting using the epoxy resin composition obtained in the above example. As a result, this optical semiconductor device had reduced internal stress and had high reliability.

Claims (1)

[Scope of Claims] (1) An optical semiconductor device 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) Organopolysiloxane having a molecular weight of 500 to 7,000 and having at least one amino group in one molecule. (C) Acid anhydride curing agent. (D) Curing catalyst. (2) The optical semiconductor device according to claim 1, wherein a blending ratio of the organopolysiloxane is set in a range of 5 to 40 parts by weight based on 100 parts by weight of the transparent epoxy resin. (3) An optical semiconductor device in which an optical semiconductor element is sealed using an epoxy resin composition containing the following components (A'), (C), and (D). (A') A transparent epoxy resin modified with an organopolysiloxane having a molecular weight of 500 to 7,000 and having at least one amino group in one molecule. (C) Acid anhydride curing agent. (D) Curing catalyst. (4) The optical semiconductor according to claim (3), wherein the modified transparent epoxy resin is obtained by reacting 5 to 40 parts by weight of organopolysiloxane with 100 parts by weight of the transparent epoxy resin. Device. (5) The optical semiconductor device according to any one of claims (1) to (4), wherein the transparent epoxy resin is at least one of a bisphenol A epoxy resin and an alicyclic epoxy resin. (6) The above organopolysiloxane has the following general formula (
The optical semiconductor device according to any one of claims (1) to (5), which is represented by I). ▲There are mathematical formulas, chemical formulas, tables, etc.▼... (I) [In the above general formula (I), R_1 and R_2 are alkyl groups with 2 or less carbon atoms, R_3 and R_4 are alkyl groups with 2 or less carbon atoms or phenyl group, and R' is a hydrocarbon residue. Further, m and n are integers, and m+n=3 to 90. ] (7) The following (A) to (
D) An epoxy resin composition for encapsulating an optical semiconductor containing component. (A) Transparent epoxy resin. (B) Organopolysiloxane having a molecular weight of 500 to 7,000 and having at least one amino group in one molecule. (C) Acid anhydride curing agent. (D) Curing catalyst. (8) Optical semiconductor encapsulation according to claim (7), wherein the blending ratio of the organopolysiloxane is set in the range of 5 to 40 parts by weight based on 100 parts by weight of the transparent epoxy resin. Epoxy resin composition for use. (9) An epoxy resin composition for optical semiconductor encapsulation containing the following components (A'), (C) and (D). (A') A transparent epoxy resin modified with an organopolysiloxane having a molecular weight of 500 to 7,000 and having at least one amino group in one molecule. (C) Acid anhydride curing agent. (D) Curing catalyst. (10) The optical semiconductor according to claim (9), wherein the modified transparent epoxy resin is obtained by reacting 5 to 40 parts by weight of organopolysiloxane with 100 parts by weight of the transparent epoxy resin. Epoxy resin composition for sealing. (11) The transparent epoxy resin is bisphenol A
The epoxy resin composition for optical semiconductor sealing according to any one of claims (7) to (10), which is at least one of a type epoxy resin and an alicyclic epoxy resin. (12) The epoxy resin composition for optical semiconductor encapsulation according to any one of claims (7) to (11), wherein the organopolysiloxane is represented by the following general formula (I). (Margin) ▲Contains mathematical formulas, chemical formulas, tables, etc.▼... (I) [In the above general formula (I), R_1 and R_2 are alkyl groups with 2 or less carbon atoms, and R_3 and R_4 are alkyl groups with 2 or less carbon atoms. or phenyl group, R' is a hydrocarbon residue, and m and n are integers, m+n=3-90. ]