JP2761284B2 - Optical semiconductor device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an optical semiconductor device without optical unevenness.

[Conventional technology]

2. Description of the Related Art Conventionally, a light-receiving element such as a solid-state imaging device is generally sealed in a hollow shape by a ceramic package to form a device. However, the above ceramic packaging is
Resin sealing using a plastic package is being studied because of the relatively high cost of the constituent materials and the disadvantage of poor mass productivity. Among resin sealing using the plastic package, resin sealing using an epoxy resin composition is being studied. The epoxy resin composition is obtained by melting and mixing an epoxy resin, a curing agent, a curing accelerator and other additives while heating.

[Problems to be solved by the invention]

However, the epoxy resin composition for encapsulating an optical semiconductor obtained by the above method has insufficient dispersibility of the epoxy resin, the curing agent and the curing accelerator, and is not uniformly mixed and dispersed to the molecular level. Therefore, for example, when transfer molding is performed using the epoxy resin composition for encapsulating an optical semiconductor as described above, the following problem occurs. That is, as shown in FIG. 3, when a tablet-shaped epoxy resin composition for encapsulating an optical semiconductor is put into a cull 1 and pressed by a plunger 2, the epoxy resin composition for optical semiconductor encapsulation is indicated by an arrow. And flows into the cavity 4 through the runner 3. Then, as shown in FIG. 4, the epoxy resin composition for optical semiconductor encapsulation passes through the gate 5 and passes through the cavity 4 as shown by the arrow.
The solid-state imaging device 7 mounted on the inner frame 6 is sealed with resin. At the time of this resin sealing, when the epoxy resin composition for optical semiconductor encapsulation is cured in the cavity 4, the dispersion state of each component of the epoxy resin composition for optical semiconductor encapsulation is not uniform at the molecular level and is non-uniform. Therefore, there are a portion where the curing reaction is fast and a portion where the curing reaction is slow, and a difference in curing density occurs due to a difference in the speed of the curing reaction. A problem arises in that optical irregularities of striped patterns extending along are formed. Such optical unevenness is obtained by applying strong parallel light to an area sensor of the solid-state imaging device 7 resin-sealed with the conventional epoxy resin composition for encapsulating an optical semiconductor as described above.
When the aperture is stopped down to −32, the image appears as a stripe pattern.

The present invention has been made in view of such circumstances,
It is an object of the present invention to provide an optical semiconductor device without optical unevenness.

[Means for solving the problem]

In order to achieve the above object, an optical semiconductor device according to the present invention is an optical semiconductor device in which an optical semiconductor element is covered with a transparent epoxy resin composition cured product, wherein the transparent epoxy resin composition cured product has the following refractive index: Distribution (A) ~
(C).

(A) The height of the maximum peak point (a) in the peak distribution curve of the refractive index is 100, and the interval between the left and right points (b) and (c) at which the relative peak height to 100 is 20 (point b) And c
The difference in refractive index between points) X is 0.0018 or less.

(B) The larger value Y of the value obtained by subtracting the refractive index at the point (b) or (c) from the refractive index at the maximum peak point (a) is 0.0012 or less.

(C) When the peak distribution curve of the refractive index has other peak points (d,... Dn) in addition to the maximum peak point (a), the refractive index at the maximum peak point (a) and the refractive index more than this The refractive index difference Z from the other peak point (d) where the index difference becomes large is 0.00
less than 10.

[Action]

That is, the present inventors have conducted a series of studies for the purpose of removing optical unevenness of the cured epoxy resin composition for encapsulating an optical semiconductor element, and as a result, the formation of the optical unevenness has a refractive index of the cured body. We found that the distribution had a significant effect.
As a result of further study on the refractive index distribution, optical unevenness is formed when the refractive index distribution of the cured product is made to be the sharp to satisfy all of the requirements (A), (B) and (C). The inventor of the present invention has found that it has disappeared.

 Next, the present invention will be described in detail.

According to the optical semiconductor device of the present invention, the above requirements (A) and (B)
And an optical semiconductor element sealed with a cured transparent epoxy resin composition satisfying (C).

The cured product satisfying the above requirements (A), (B) and (C)
It has a sharp refractive index distribution having a narrower distribution width than the refractive index distribution of a normal cured epoxy resin composition.
Such requirements (A), (B), and (C) will be described with reference to the drawings. FIG. 1 shows a peak distribution curve of the refractive index of one example of the cured transparent epoxy resin composition used in the present invention, where K is a peak distribution curve, a is its maximum peak point, and b and c are maximum peak points a. X is the difference between the refractive indices at points b and c, and Y is the point b or c from the refractive index at the maximum peak point a, where the relative peak height is 20 when the height of the point is 100.
It is the larger of the values obtained by subtracting the refractive index of the point (in the figure, the value of the refractive index of the point c is smaller than the value of the point a because the value of the refractive index of the point c is smaller than that of the point b). The value is Y). The above Y can be said to be the difference between the refractive index at the maximum peak point a and the refractive index at the point c (or point b). As long as the above requirements (A) and (B) are satisfied, the peak distribution curve of the refractive index has another peak point a 'other than the maximum peak point a as shown in FIG. However, optical unevenness does not occur. However, when the number of pixels of the solid-state imaging device is dramatically increased compared to the current one, or when a function of enhancing the difference in refractive index is provided by a microlens, the above-mentioned requirement (A) X Is preferably set to 0.0010 or less, and the value of Y in the requirement (B) is set to 0.0007 or less. It is particularly preferable that the value of X is 0.0007 or less and the value of Y is 0.0004 or less. By setting in this way, even if the number of pixels of the solid-state imaging device increases dramatically in the future, there will be no obstacle to optical unevenness. Also,
As described above, if there is another peak point a ′ other than the maximum peak point a, it may cause an obstacle to optical unevenness. However, even when a plurality of peak points are provided, the maximum peak point a and the maximum peak point a
Is compared with another peak point (point a 'in FIG. 2) at which the difference in refractive index is the largest, and the difference in refractive index between the two points (points a and a' in FIG. 2). The refractive index difference Z) is set to be 0.0010 or less, preferably 0.0003 or less, so that in the future, even if the number of pixels of the solid-state imaging device is dramatically increased, optical unevenness may occur. There is no.

The refractive index shown in FIGS. 1 and 2 can be measured using a refractive index measuring apparatus to which the principle shown in FIG. 6 is applied. In FIG., F is an interference filter, SL spectrum light source lamp, S ₁ is the entrance slit, S ₂ is the exit slit, L ₁ is a collimator lens, L ₂ is telemeter lens, P is V Bro poke prism, SM is a measurement sample, PM Is a photomultiplier tube, and N is a telemeter unit. In this apparatus, a cured product of a transparent epoxy resin composition is finished into, for example, a cubic sample SM, and two adjacent surfaces are polished to a surface roughness of 1.5 μm or less by buffing with a degree of polishing, and the surface is polished into a V-shaped groove. The two polished surfaces are mounted on the block prism P so as to match the V-shaped grooves, and light is projected from the light source SL. Light emitted from the light source SL becomes a monochromatic light by the interference filter F, through the inlet slit S _1, and summer and parallel beam by a collimator lens L _1, V Bro poke prism P → Sample
The light passes through the order of SM → V block prism P and is polarized upward and downward along the optical axis due to the difference in refractive index between the V block prism P and the sample SM. A telemeter unit N including a telemeter lens L ₂ , an exit slit S ₂ , and a photomultiplier tube PM includes:
As shown by the arrow in the drawing, the head is swung by a pulse motor (not shown), and the polarized light is received at each swing position, and the amount of received light is displayed on a display (not shown) as an energy amount. . In this case, the correlation between each angle and the refractive index in the swinging motion is obtained in advance, and the amount of received light at a certain angle is that of the refractive index corresponding to that angle. This refractive index measuring device is manufactured and sold as an automatic refractive index measuring device KPR-200 by Carneuux Optical Co., Ltd. (Japan). In the present invention, this apparatus is used, and the refractive index is measured using a sodium D line (587.6 nm) as a light source.

The transparent epoxy resin composition cured body that does not cause optical unevenness has a refractive index distribution obtained as described above, which satisfies the above requirements (A), (B), and (C).

As a specific method for producing an epoxy resin composition capable of producing such a sharp cured product having a refractive index distribution, for example, the components of the epoxy resin composition are uniformly dispersed. As a method of uniformly dispersing the epoxy resin composition, a conventional epoxy resin composition powder for encapsulation, which is a B-stage (semi-cured) epoxy resin composition, is sufficiently mixed with an organic solvent to dissolve each component. Evaporate the organic solvent or mix each component material such as epoxy resin, curing agent, curing accelerator, etc. with the organic solvent to dissolve uniformly, and heat this solution in the dissolving stage to make it B-staged. There is a method of producing the epoxy resin composition for encapsulating an optical semiconductor by evaporating or evaporating the solvent and then gently heating the mixture to form a B stage. Further, in each of the above methods, since the epoxy resin composition or its raw material is once dissolved in an organic solvent, by filtering this solution, it is possible to easily remove fine foreign matter such as dust which cannot be removed conventionally. Becomes possible. Further, by uniformly mixing the obtained composition into a fine powder, even if the maximum peak point a and the other peak point a ′ coexist in the peak distribution curve of the refractive index, it is relaxed. As a result, as shown in FIG. 1, the peak distribution curve has only the maximum peak point a, and the peak distribution curve itself becomes sharp, so that the values of X and Y shown in FIG. 1 become small. Here, the fine powder generally refers to a powder having a maximum particle size of 30 μm or less, preferably 10 μm or less, at a proportion of 90% by weight or more.

The epoxy resin composition for optical semiconductor encapsulation used in the present invention is obtained using an epoxy resin, a curing agent and a curing accelerator, and does not use an inorganic filler such as silica powder.

The epoxy resin is not particularly limited as long as it is a conventionally known epoxy resin having little coloring. For example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenol novolak type epoxy resin, alicyclic epoxy resin, heterocyclic epoxy resin such as triglycidyl isocyanurate, hydantoin epoxy, etc., and water-added bisphenol A Type epoxy resin, aliphatic epoxy resin, glycidyl ether type epoxy resin, and the like, which are used alone or in combination.

As the above-mentioned curing agent, an acid anhydride with little coloring in the cured product of the resin composition during or after curing is suitable, but is not particularly limited. For example, as the acid anhydride,
Phthalic anhydride, maleic anhydride, trimellitic anhydride,
Examples include pyromellitic anhydride, hexahydrophthalic anhydride, tetrahydrophthalic anhydride, methyl nadic anhydride, nadic anhydride, and glutaric anhydride. Examples of the amine-based curing agent include metaphenylenediamine, dimethyldiphenylmethane, and diaminodiphenyl. Sulfone, m-xylenediamine, tetraethylenepentamine, diethylamine, propylamine and the like can be mentioned. Further, a phenolic resin-based curing agent may be used, and any of them may be used.

Examples of the curing accelerator include tertiary amines, imidazoles, metal salts of carboxylic acids, and phosphorus compounds.

In the epoxy resin composition for encapsulating an optical semiconductor used in the present invention, conventionally known additives such as a coloring inhibitor, a denaturing agent, a deterioration preventing agent, a release agent, etc. may be used in addition to the above-mentioned components. Can be

Examples of the coloring inhibitor include conventionally known compounds such as phenol compounds, amine compounds, organic sulfur compounds, and phosphine compounds.

The organic solvent is not particularly limited as long as it can completely dissolve the B-staged epoxy resin composition for optical semiconductor encapsulation. For example, hydrocarbon-based organic solvents such as toluene and xylene, halogenated hydrocarbon-based organic solvents such as dichloromethane, 1,1,1-trichloroethane and 1,1,2-trichloroethane, and ether-based solvents such as diethyl ether, dioxane and tetrahydrofuran Organic solvents, ketone-based organic solvents such as acetone, methyl ethyl ketone, diethyl ketone and the like, and a mixed solution thereof and the like can be mentioned. Further, the mixing ratio and the mixing temperature of the organic solvent with respect to the epoxy resin composition for optical semiconductor encapsulation are not particularly limited as long as the epoxy resin composition for optical semiconductor encapsulation can be completely dissolved. However, the mixing ratio of the organic solvent is usually preferably 1 to 50 times (weight ratio), more preferably 1 to 10 times, that of the B-staged epoxy resin composition for encapsulating an optical semiconductor. The mixing temperature is preferably kept at 100 ° C. or lower, because if the temperature is too high, the epoxy resin composition for encapsulating an optical semiconductor gels.

Further, as a method for removing the organic solvent in the above-mentioned production method, a method of removing the organic solvent by heating at room temperature or if necessary, and then reducing the pressure, a method of removing the organic solvent by a vacuum freeze-drying method, and the like can be mentioned. is not. The residual amount of the organic solvent needs to be set to 3% by weight or less of the entire epoxy resin composition for optical semiconductor encapsulation. It is preferably at most 1.5% by weight, more preferably at most 0.05% by weight. That is, when the residual amount of the organic solvent exceeds 3% by weight, the pot life of the epoxy resin composition for encapsulating an optical semiconductor becomes extremely short, the glass transition temperature of the cured product decreases, and the linear expansion coefficient increases, As a result, the moisture resistance and the heat cycle property of the sealing resin are reduced.

Since the epoxy resin composition for optical semiconductor encapsulation obtained by the above method is in a state where each component is uniformly mixed at the molecular level, the distribution of the refractive index of the cured product becomes a shear and the optical unevenness is obtained. Does not occur. In addition, in order to dissolve each component material in an organic solvent during the manufacturing process, a resin composition which can be easily subjected to reduced pressure suction filtration or pressure filtration using an existing filter paper filter or the like, which has conventionally been difficult to remove. It is possible to easily remove foreign substances such as gel-like substances and fine dust therein. In addition, since such an epoxy resin composition for optical semiconductor encapsulation is used for resin encapsulation of an optical semiconductor such as a light receiving element, a transparent one is preferable from an optical viewpoint. "Transparent" in this case, the transmittance at 400 nm of the cured product of the epoxy resin composition for optical semiconductor encapsulation,
Usually 90% or more, preferably 95% or more, particularly preferably 98%
% (The thickness of the cured product is 1 mm).

The sealing of the light receiving element and the like using the epoxy resin composition for optical semiconductor sealing is not particularly limited,
It can be performed by a known molding method such as ordinary transfer molding. When carrying out the transfer molding, the powdery composition is usually used as a tablet at room temperature.

The optical semiconductor device obtained in this manner is, for example, as shown in FIG.
The solid-state imaging device 13 which is a light receiving device is mounted through, and a color filter 15 is adhered to the upper portion thereof using a transparent adhesive 14, and these are resin-sealed with an optical semiconductor sealing epoxy resin composition 16. It is configured. Note that the color filter 15 is provided to obtain a color image, and is unnecessary in monochrome. In the figure, 17 is a glass plate, 18 is a bonding wire, and 19 is a lead frame.

Since this optical semiconductor device is resin-encapsulated with an epoxy resin composition for optical semiconductor encapsulation in which each component is uniformly mixed to the molecular level, the refractive index distribution is sharp, and the encapsulating resin 16 No optical unevenness has occurred. Therefore, in the image obtained by operating this, no striped pattern due to optical unevenness and no black spot due to the contaminated foreign matter are observed. By the way, the thickness l of the sealing resin on the color filter 15 is
When an optical semiconductor device obtained by setting the thickness to 0.5 to 2 mm was used, optical unevenness did not occur.

〔The invention's effect〕

As described above, according to the optical semiconductor device of the present invention, the refractive index distribution of the transparent epoxy resin cured product has the above-mentioned (A), (B),
Since it is as shown in (C), optical unevenness does not occur.
In addition, when the transparent epoxy resin cured product is prepared by dissolving an epoxy resin composition using an organic solvent and using the same, it is possible to remove foreign substances by filtration, and it has conventionally been difficult to remove the resin. Foreign matters such as gel-like substances and fine dust in the composition are removed, resulting in high quality.
Therefore, for example, the optical semiconductor device of the present invention in which a light receiving element such as a solid-state image sensor is sealed with a resin is formed on a formed image by a stripe pattern caused by optical unevenness of the resin or by a foreign matter in the sealing resin. It is a high-performance product that does not show black spots, and exhibits the same or better performance as a ceramic package product, even though it is a sealing resin product.

 Next, examples will be described together with comparative examples.

First, prior to the examples, formulations for six types of epoxy resin compositions shown in Table 1 below were prepared.

Next, the following epoxy resin compositions A to F were prepared according to the above formulation examples.

[Epoxy resin composition A]

After heating and melting and mixing the respective raw materials at the ratios shown in the mixing examples shown in Table 1 above, the curing reaction of the epoxy resin was allowed to proceed, and a B-stage optical semiconductor encapsulation having a gel time of 30 seconds at a temperature of 150 ° C. An epoxy resin composition was prepared. This B-staged epoxy resin composition for encapsulating an optical semiconductor is
It was completely dissolved in the organic solvent in the amount shown in Table 2 below,
Then, the pressure was reduced while heating to 45 ° C., and the mixture was pulverized to obtain a residual organic solvent having a temperature of 150
Powdered epoxy resin composition A for optical semiconductor encapsulation (for Example 1) having a gelation time at 25 ° C. of 25 seconds was obtained.

[Epoxy resin composition B]

In accordance with the formulation examples shown in Table 1 above, two formulations were made. Next, a curing reaction of the epoxy resin was progressed for each of these, and a B-stage epoxy resin composition for encapsulating an optical semiconductor having a gelation time of 30 seconds at a temperature of 150 ° C. was produced. These two types of B
50 parts of the stage-shaped epoxy resin composition for encapsulating an optical semiconductor were mixed, and completely dissolved and mixed in an organic solvent having a compounding amount shown in Table 2 below. Next, after reducing the pressure while heating the mixture to 45 ° C., it was pulverized to obtain a powdery optical semiconductor encapsulation having a gelling time of 25 seconds at a temperature of 150 ° C. with the amount of the remaining organic solvent shown in Table 2. An epoxy resin composition B (for Example 2) was obtained.

[Epoxy resin composition C]

After heating and melting and mixing the respective raw materials according to the formulation examples shown in Table 1 above, the curing reaction of the epoxy resin is advanced,
An epoxy resin composition for optical semiconductor encapsulation in the form of a B-stage having a gel time of 30 seconds at 150 ° C. was prepared. This B-staged epoxy resin composition for encapsulating an optical semiconductor was prepared by the following second step.
It was completely dissolved and mixed in an organic solvent having the compounding amount shown in the table. Next, the pressure was reduced while heating the mixture to 45 ° C., and the resulting mixture was pulverized to obtain the remaining organic solvent in the amount shown in Table 2 below.
A powdered epoxy resin composition for encapsulating an optical semiconductor having a gelation time at 150 ° C. of 25 seconds was obtained. 40 parts of this epoxy resin composition and 60 parts of the epoxy resin composition A were dry-blended to obtain an epoxy resin composition C for optical semiconductor encapsulation of Example 3 (for Example 3).

[Epoxy resin composition D]

After heating and melting and mixing the respective raw materials according to the formulation examples shown in Table 1 above, the curing reaction of the epoxy resin is advanced,
An epoxy resin composition for optical semiconductor encapsulation in the form of a B-stage having a gel time of 30 seconds at 150 ° C. was prepared. This B-staged epoxy resin composition for encapsulating an optical semiconductor was prepared by the following second step.
It was completely dissolved and mixed in an organic solvent having the compounding amount shown in the table. Then, the mixture was decompressed while being heated to 45 ° C., and then pulverized to obtain the remaining organic solvent in the amount shown in Table 2 below.
A powdered epoxy resin composition for encapsulating an optical semiconductor having a gelation time at 150 ° C. of 25 seconds was obtained. 40 parts of this epoxy resin composition and 60 parts of the epoxy resin composition A were dry blended to obtain an epoxy resin composition D for encapsulating an optical semiconductor (Example 4).
For) obtained.

[Epoxy resin composition E]

The epoxy resin composition A was subjected to jet mill pulverization so that the ratio of the maximum particle size of 30 μm or less occupied 90% by weight or less and the average particle size was 10 μm, to obtain an epoxy resin composition E for optical semiconductor encapsulation (for Example 5). Obtained.

[Epoxy resin composition F]

The epoxy resin composition A was subjected to jet mill pulverization so that the proportion occupying a maximum particle diameter of 10 μm or less was 90% by weight or less and the average particle diameter was 4 μm, to obtain an epoxy resin composition F for optical semiconductor encapsulation (for Example 6). Obtained.

[Epoxy resin composition G]

The respective raw materials were blended according to the blending examples shown in Table 1 above, and were heated and melt-mixed without using an organic solvent, and then the curing reaction of the epoxy resin was allowed to proceed. Crush this to a temperature of 150 ° C
, A powdered epoxy resin composition G for optical semiconductor encapsulation (for Comparative Example 1) having a gelation time of 25 seconds was obtained.

[Epoxy resin composition H]

After heating and melting and mixing the raw materials according to the composition shown in Table 1 above, the curing reaction of the epoxy resin is advanced,
A B-stage epoxy resin composition for encapsulating an optical semiconductor having a gelation time of 30 seconds at 150 ° C. was prepared and pulverized. Next, 35 parts of the epoxy resin composition and 65 parts of the composition A were dry blended to obtain an epoxy resin composition H
(For Comparative Example 2) was obtained.

[Epoxy resin composition I] After heating and melting and mixing the respective raw materials according to the composition shown in Table 1 above, the curing reaction of the epoxy resin was advanced,
A B-staged epoxy resin composition for encapsulating an optical semiconductor having a gelation time of 30 seconds at 150 ° C. was prepared and pulverized. 20 parts of this epoxy resin composition and 80 parts of the epoxy resin composition A were dry-blended to obtain an epoxy resin composition I (Comparative Example 3).
For) obtained.

[Examples and Comparative Examples] <Measurement of Refractive Index> Next, the nine types of powdery epoxy resin compositions (A to I) obtained as described above were each formed into a tablet at room temperature, and this was molded. After transfer molding at 150 ° C. for 6 minutes, the mixture was further cured at 150 ° C. for 3 hours to form seven 12 mm square cubes. For these cured products, two adjacent surfaces were polished by buffing, and the polished surface was finished to a surface roughness of 1.5 μm or less.
To I), and the apparatus shown in FIG.
(PR-200 automatic refractometer). The results are shown in FIGS.
Shown in the figure. Samples A to F are examples and samples GI are comparative examples. As is clear from the refractive index distribution curves of FIGS. 7 to 12 corresponding to Samples A to F and the values of X, Y and Z in Table 2, the above Samples A to F satisfy the requirements of the present invention ( A), (B) and (C) are satisfied. In particular, in FIGS. 9 and 10 corresponding to samples C and D, other peak points a 'appear in addition to the maximum peak point a.
9 and 10, the refractive index difference Z between a and a '
As is clear from the value of Z in the table, the value falls within 0.0010 or less. On the other hand, Samples G and H, which are comparative examples, have corresponding refractive index distribution curves in FIGS. 13 and 14 and X,
As is apparent from the value of Y, the requirement (A) of the present invention,
(B) is not satisfied. Sample I, which is also a comparative example, has a refractive index distribution curve diagram in FIG. 15 and X,
As is apparent from the value of Y, although the above requirements (A) and (B) are satisfied, the maximum peak point a and the other peak points a 'between the two points a and a' Index difference Z
Exceeds 0.0010. Therefore, the requirement (C) of the present invention is not satisfied.

<Manufacture of Optical Semiconductor Device> Using the above nine types of powdered epoxy resin compositions (A to I), an area sensor, which is actually a solid-state imaging device, is directly molded (150 ° C. × 6 minutes, after-cure 150 × 3).
Time). Next, a camera was assembled using this, and strong parallel light (luminous intensity of 10 candela) was applied to the camera at right angles, and the image obtained when the camera aperture was stopped down to F-32 was displayed on a display screen. As a result, as shown in the column of optical nonuniformity A in Table 2, no optical nonuniformity was observed in the images of the six examples using compositions A to F separately. In contrast, optical unevenness was observed in the images of three types of comparative examples using each of the compositions G to I, and stripes appeared in a part of the images.

In addition, a runner-shaped flat plate (thickness 3.0 mm, width 5 m) left on the runner part of the mold during the above direct molding
For m), the occurrence of optical unevenness was examined as follows. That is, 38 in 1/2 inch built into the camera
The surface is polished on the area sensor encapsulant, which is a 10,000 pixel solid-state image sensor, and the polished surface has a surface roughness of 1.5 μm
When a runner-shaped flat plate with the following irregularities and a curved portion of 120 ° is placed, strong parallel light (luminous intensity 10 candela) is applied at a right angle, and the aperture of the camera is reduced to F-32. The image was examined for the presence of a vertical pattern. The polymer in the runner part has a thickness of 3.0 mm and it is easy for striped patterns to appear,
Therefore, this measurement is more strict than the evaluation of the optical nonuniformity A in the evaluation of the optical nonuniformity, and predicts an increase in the number of pixels of the solid-state imaging device in the future, and examines whether or not it can cope with it. . As a result, as shown in the column of optical unevenness B in Table 2, no striped pattern appeared in Examples using each of the epoxy resin compositions A, C, E, and F. No unevenness was observed, but a striped pattern appeared slightly in Examples using Compositions B and D separately. On the other hand, strips appeared in Comparative Examples using each of Compositions GI. In the evaluation of the optical unevenness B, the luminous intensity of the parallel light was set to 20 candelas, and this light was applied at a right angle to check the presence or absence of a stripe pattern in the image when the aperture of the camera was stopped down to F-45. And The evaluation of the optical unevenness C is a further strict evaluation of the optical unevenness B. As a result, as shown in the column of optical unevenness C in Table 2, slightly striped patterns appeared in Examples 1 to 4 using the epoxy resin compositions A, B, C, and D separately. No optical unevenness was observed in the products of Examples using the finely pulverized epoxy resin compositions E and F separately. On the other hand, striped patterns appeared in all of the comparative examples using compositions G to I.

The non-adjacent two surfaces (two parallel surfaces) of the seven cured cubes of 12 mm square used in the refractive index measurement were polished, and the polished surface was finished to have a surface roughness of 1.5 μm or less.
I). Using this sample, the light transmittance was measured with a Shimadzu self-recording spectrophotometer UV-3101PC manufactured by Shimadzu Corporation. Table 2 shows the results. From these facts, it can be seen that as shown in FIGS. 7 to 12, the sharper the refractive index distribution, the better the light transmittance.

[Brief description of the drawings]

FIG. 1 is a refractive index distribution diagram having only a maximum peak, FIG. 2 is a refractive index distribution diagram having a maximum peak and other peaks, and FIG. 3 is a diagram showing a conventional optical semiconductor encapsulating epoxy resin composition. FIG. 4 is a flow diagram of the resin composition at the time of transfer molding, FIG.
The figure is a longitudinal sectional view of an optical semiconductor device encapsulated with the epoxy resin composition for optical semiconductor encapsulation of the present invention, FIG. 6 is a principle diagram of a refractive index measuring device, FIGS. 7, 8, and 9 Fig. 10, Fig. 10,
FIG. 11, FIG. 12, FIG. 13, FIG. 14 and FIG. 15 are refractive index distribution curves. 11: bonding pad, 12: adhesive, 13: solid-state image sensor, 14: transparent adhesive, 15: color filter, 16: epoxy resin composition for encapsulating optical semiconductors, 17:
Glass plate, 18 ... Bonding wire, 19 ... Lead frame

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Yasuhiko Yamamoto 1-1-2 Shimohozumi, Ibaraki-shi, Osaka Nippon Denko Corporation (72) Inventor Nobuyuki Hiromori 1-2-1, Shimohozumi, Ibaraki-shi, Osaka (1) 1-2, Shimohozumi, Ibaraki-shi, Osaka Prefecture, Japan No. 1 1-2-1, Shimohozumi, Ibaraki-shi, Osaka Japan-72 Katsuya Muramatsu, 1-2-1, Shimohozumi, Ibaraki-shi, Osaka, Japan No. Japan Todenko Co., Ltd.

Claims (5)

(57) [Claims] 1. An optical semiconductor device comprising an optical semiconductor element covered with a cured transparent epoxy resin composition, wherein the cured transparent epoxy resin composition has the following refractive index distributions (A) to (C). An optical semiconductor device characterized by the above-mentioned. (A) The height of the maximum peak point (a) in the peak distribution curve of the refractive index is 100, and the interval between the left and right points (b) and (c) at which the relative peak height to 100 is 20 (point b) And c
The difference in refractive index between points) X is 0.0018 or less. (B) The larger value Y of the value obtained by subtracting the refractive index at the point (b) or (c) from the refractive index at the maximum peak point (a) is 0.0012 or less. (C) When the peak distribution curve of the refractive index has other peak points (d,... Dn) in addition to the maximum peak point (a), the refractive index at the maximum peak point (a) and the refractive index more than this The refractive index difference Z from the other peak point (d) where the index difference becomes large is 0.00
less than 10. 2. The optical semiconductor device according to claim 1, wherein the value of Z in the requirement (C) is set to 0.0003 or less. 3. The optical semiconductor device according to claim 1, wherein the value of X in the requirement (A) is set to 0.0015 or less. 4. The value of X in the requirement (A) is 0.0010 or less,
3. The optical semiconductor device according to claim 1, wherein the value of Y in the requirement (B) is set to 0.0007 or less. 5. The value of X in the requirement (A) is 0.0007 or less,
The optical semiconductor device according to claim 1, wherein the value of Y in the requirement (B) is set to 0.0004 or less.