JPH033258A - Optical semiconductor device, manufacture of the same, and optical semiconductor sealing resin composition used therefor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an optical semiconductor device with no optical unevenness, a method for manufacturing the same, and a resin composition for encapsulating an optical semiconductor used therein.

(Prior Art) Conventionally, a light receiving element such as a solid-state image sensor has generally been sealed in a hollow shape with a ceramic package and made into a device. However, the above-mentioned ceramic package has disadvantages of relatively expensive constituent materials and poor mass productivity, and therefore resin sealing using a plastic package is being considered. Among the resin sealing methods using the above-mentioned plastic packages, resin sealing using an epoxy resin composition is particularly being considered. The above-mentioned epoxy resin composition is obtained by melt-mixing an epoxy resin, a curing agent, a curing accelerator, and other additives while heating.

[Problem that the invention seeks to solve]

However, in the epoxy resin composition for optical semiconductor encapsulation obtained by the above method, the components of the epoxy resin curing agent and curing accelerator have insufficient dispersibility and are not uniformly mixed and dispersed. Therefore, for example, when transfer molding is performed using the above-mentioned epoxy resin composition for encapsulating an optical semiconductor, the following problems arise. That is,
As shown in FIG. 1, when a tablet-shaped epoxy resin composition for encapsulating optical semiconductors is put into a cull 1 and pressed with a plunger 2, the epoxy resin composition for encapsulating optical semiconductors forms as shown by the arrow. It flows and passes through the runner 3 and flows into the cavity 4. As shown in FIG. 2, the epoxy resin composition for optical semiconductor sealing passes through the gate 5 as shown by the arrow, and seals the solid-state image sensor 7 mounted on the frame 6 in the cavity 4 with the resin. do. When the epoxy resin composition for optical semiconductor encapsulation is cured in the cavity 4 during this resin encapsulation, the curing reaction is rapid because the dispersion state of each component of the epoxy resin composition for optical semiconductor encapsulation is uneven. The difference in curing reaction speed between the curing reaction speeds causes a difference in curing density, which causes a problem in that optical unevenness in a striped pattern extending along the flow direction of the resin is formed in the sealing resin. Such optical unevenness can be caused, for example, when the area sensor of the solid-state image sensor 7 is resin-sealed with the conventional epoxy resin composition for sealing optical semiconductors as described above, when strong parallel light is applied to the sealing body and the aperture is closed. When stopped down to F-32, a striped pattern appears in the uppermost image.

The present invention was made in view of the above circumstances, and an object thereof is to provide a resin composition for encapsulating optical semiconductors that does not cause optical unevenness in a cured product, an optical semiconductor device using the same, and a method for manufacturing the same. shall be.

[Means for solving the problems] In order to achieve the above object, the present invention provides that - the sealing resin is
A B-stage epoxy resin composition for encapsulating optical semiconductors comprising an epoxy resin, a curing agent, and a curing accelerator, which are uniformly pulverized and mixed, and the proportion of particles with a maximum particle size of 30 μm or less is 90% by weight. % or more of the cured product of the resin composition.
This is an epoxy resin composition for a B-stage optical semiconductor enclosure containing an epoxy resin, a curing agent, and a curing accelerator as constituent components, which is uniformly pulverized and mixed, and has a maximum particle size of 3.
The second gist is an epoxy resin composition for optical semiconductor encapsulation in which the proportion of particles of 0 μm or less is set to 90% by weight or more, and the above-mentioned epoxy resin composition for optical semiconductor encapsulation is used, and by cold molding. The third aspect is an epoxy resin composition for encapsulating optical semiconductors that is made into a tablet, and describes an optical semiconductor device in which an optical semiconductor element is encapsulated by transfer molding using the epoxy resin composition for encapsulating optical semiconductors. The manufacturing method is the fourth gist, and the sealing resin is a B-stage thermosetting resin composition for optical semiconductor sealing, which contains a thermosetting resin and a curing agent as constituent components, and is homogeneously mixed into fine powder. The fifth aspect is an optical semiconductor device composed of a cured product of a resin composition in which the ratio of particles with a maximum particle size of 30 μm or less is set to 90% by weight or more, and a thermosetting resin and a curing agent are used. A B-stage thermosetting resin composition for encapsulating optical semiconductors as a constituent component, which is uniformly pulverized and mixed, and the proportion of particles with a maximum particle size of 30 μm or less is set to 90% by weight or more. The sixth aspect is a thermosetting resin composition for semiconductor encapsulation.

[Effect]

That is, in the process of conducting a series of studies to obtain an epoxy resin composition for encapsulating optical semiconductors that does not cause optical unevenness, the present inventors discovered that the particle size of the composition itself may affect optical unevenness. I came up with an idea and did a lot of research around this idea. As a result, the particle size of the conventional sealing epoxy resin composition obtained by grinding the epoxy resin composition into a B-stage state (semi-cured state) was insufficient for micronization. The present invention was achieved by discovering that when the particles are pulverized to a ratio of 90% by weight or more (hereinafter abbreviated as "%"), this becomes a critical point and almost no optical unevenness occurs in the cured product.

Note that the above-mentioned finely pulverized particles are uniformly mixed and no optical unevenness occurs when the surface is polished and the surface roughness of the polished surface is 1.5 μm.
A cured resin product (after transfer molding at 150°C for 6 minutes) is finished into a runner-shaped flat plate (thickness: 3.0 mm, width: 5 a) with an unevenness difference of less than m and a 120° curved part. , which was further cured at 150°C for 3 hours and then removed from a part of the runner of the mold) was mounted on a 1/2 inch (1,27 cm) 380,000 pixel type solid-state image sensor, and the luminous intensity was 10. This refers to a state in which no striped pattern appears in the image when strong parallel light from a candela is applied at right angles and the aperture is stopped down to F-32.

The epoxy resin composition for encapsulating optical semiconductors of the present invention is obtained using an epoxy resin, a curing agent, and a curing accelerator, and fillers such as silica powder are not used because they impair light transmission.

The above-mentioned epoxy resin is not particularly limited as long as it is a conventionally known epoxy resin with little coloring. for example,
Bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenol novolac type epoxy resin,
Alicyclic epoxy resins include heterocyclic epoxy resins such as triglycidyl isocyanate and hydantoin epoxy, water-added bisphenol A type epoxy resins, aliphatic epoxy resins, glycidyl ether type epoxy resins, etc.
Used alone or in combination.

The curing agent is preferably an acid anhydride that causes little coloring of the cured product of the resin composition during or after curing, but is not particularly limited. For example, the acid anhydrides include phthalic anhydride, maleic anhydride, trimellitic anhydride, pyromellitic anhydride, hexahydrophthalic anhydride, tetrahydrophthalic anhydride, methylnadic anhydride, nadic anhydride, glutaric anhydride, etc. Examples of the amine curing side include metaphenylenediamine, dimethyldiphenylmethane, diaminodiphenylsulfone m-xylenediamine, tetraethylenepentamine, diethylamine,
Examples include propylamine. Further examples include phenolic resin curing agents, and any of them may be used.

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

In addition to the above-mentioned components, the epoxy resin composition for encapsulating optical semiconductors of the present invention may optionally contain a coloring inhibitor, a modifier,
Conventionally known additives such as deterioration inhibitors and mold release agents are used.

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

The epoxy resin composition for optical semiconductor encapsulation of the present invention can be produced, for example, as follows. That is, first, the above-mentioned raw materials for each component are mixed to prepare a B-stage (semi-cured) epoxy resin composition for sealing an optical semiconductor.

As a method for mixing the above-mentioned raw materials for each component, a melt mixing method is generally used.

At this time, a low temperature reaction may be performed if necessary. Next, the epoxy resin composition for encapsulating an optical semiconductor can be manufactured by pulverizing the B-stage epoxy resin composition for encapsulating an optical semiconductor and, if necessary, tableting it. The above-mentioned tableting method is not particularly limited, but for example, cold forming is generally used to form tablets with a
0 kg/cd, preferably 1000-2000 kg
An example of this method is to perform the test under the conditions of /c4. In this way, even if the finely pulverized epoxy resin composition for encapsulating optical semiconductors is compressed into tablets, almost no optical unevenness occurs in the cured product.

Further, the above-mentioned pulverization method is not particularly limited as long as it can obtain the pulverized particle size shown below, and includes, for example, a jet mill pulverization method. The epoxy resin composition for encapsulating optical semiconductors needs to contain 90% or more of particles with a maximum particle size of 30 μm or less by pulverization using the above method. Preferably, it contains 90% or more of particles with a maximum particle size of 20 μm or less, more preferably 90% or more of particles with a maximum particle size of 10 μm or less, and particularly preferably 90% or more of particles with a maximum particle size of 1.0 μm or less. It is. Incidentally, in the present invention, when the epoxy resin composition is pulverized and particles with a maximum particle size of 30 μl or less account for at least 90%, the remainder is 30 to 10 μl.
It has a particle size of 0 μm.

In addition, when performing the above tableting process and fine grinding work,
By pulverizing the epoxy resin composition for optical semiconductor encapsulation, it becomes easy to absorb moisture, and if moisture is absorbed, the glass transition temperature of the cured product of the epoxy resin composition will be lowered. It is preferable to carry out the test in an environment with little turbulence.

The epoxy resin composition for optical semiconductor encapsulation obtained by the above method does not have curing unevenness in its cured product as a result of employing the above structure. Note that such an epoxy resin composition for optical semiconductor encapsulation is preferably transparent from an optical point of view, since it is used for resin encapsulation of optical semiconductor elements such as light receiving elements. In this case, "transparent" means that the cured product of the epoxy resin composition for encapsulating an optical semiconductor has a transmittance of 98% or more at 400 nm.

Encapsulation of an optical semiconductor element such as a light receiving element using such an epoxy resin composition for optical semiconductor sealing can be performed by ordinary transfer molding.

The optical semiconductor device obtained in this way is, for example, a third
As shown in the figure, apply adhesive 1 on bonding pad 11.
A solid-state image element 13, which is a light receiving element, is mounted via 2,
A color filter 15 is adhered to the top using a transparent adhesive, and these are resin-sealed with an epoxy resin composition 16 for sealing optical semiconductors. Note that the color filter 15 is provided to obtain a color image, and is not necessary for monochrome images. 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-sealed with the epoxy resin composition for optical semiconductor sealing of the present invention, no optical unevenness occurs in the sealing resin 16. Therefore, images obtained by operating this device do not have striped patterns due to optical unevenness.

By the way, the thickness of the sealing resin on the color filter 15 is 2.
When using an optical semiconductor device obtained by setting 0.5 to 2 degrees as usual, no optical unevenness occurred.

〔Effect of the invention〕

As described above, the epoxy resin composition for optical semiconductor encapsulation of the present invention has the value found by the present inventors as a critical point at which optical unevenness does not occur (90% or more of particles have a maximum particle size of 30 μm or less). Since it is finely pulverized so as to satisfy the following, when it is cured by transfer molding, for example, there is almost no curing unevenness as in conventional methods. therefore,
The above-mentioned epoxy resin composition for encapsulating an optical semiconductor can be particularly suitably used as a encapsulating material for a light-receiving element of a compact disc (CD) or a encapsulating material for a line sensor or area sensor, which is a solid-state image sensor.

An optical semiconductor device in which a light-receiving element such as a solid-state image sensor is encapsulated with the resin using such an epoxy resin composition for optical semiconductor sealing has a striped pattern in the formed image due to optical unevenness of the resin. It is a high-performance product that does not exhibit any side effects, and although it is a resin-sealed product, it exhibits performance equivalent to or better than ceramic packaged products.

In the above explanation, epoxy resin is used as a representative example of thermosetting resin, but it is not limited to epoxy resin in particular, and other thermosetting resins may be used, and a curing agent may be added to the essential components. A similar effect can be obtained by using the following.

Next, examples will be described together with comparative examples.

By heating and melting and mixing the raw materials shown in the table below in the proportions shown in the table, and then proceeding with the curing reaction at a low temperature, B-stage optical semiconductor sealing with a gelation time of 30 seconds at a temperature of 150°C is achieved. An epoxy resin composition was prepared. Next, this B-stage epoxy resin composition for encapsulating an optical semiconductor was pulverized to the particle size shown in the table to obtain the desired epoxy resin composition for encapsulating an optical semiconductor. In addition, as the above-mentioned pulverization method, jet mill pulverization was performed for Examples 1 to 9, and ball mill pulverization was performed for Comparative Examples 1 to 7.

(Left below) [Examples 1 to 9, Comparative Examples 1 to 7] Next, using the powdered epoxy resin composition for encapsulating optical semiconductors obtained in Example 1, a solid-state image sensor was actually manufactured. A camera was assembled using the area sensor obtained by direct molding, and when strong parallel light was applied to it and the aperture of the camera was stopped down to F-32, the image was captured on a display screen. As a result, no optical unevenness was observed in the image. Images were also obtained in the same manner as above for the powdered epoxy resin compositions for sealing optical semiconductors obtained in Examples 2 to 8. As a result, no optical unevenness was observed in the image, similar to the above. The thickness of the sealing resin on the solid-state image sensor at this time was 1 m+n, and similar results were obtained even if this thickness was used in two plates. Next, using the powdered epoxy resin composition for encapsulating optical semiconductors obtained in Comparative Example 1, the same operation as above was carried out, and the resulting image was transferred onto a display screen. As a result, optical unevenness was observed, and similar results were obtained for Comparative Examples 2 to 7. The presence or absence of the optical unevenness is also shown in the table as optical unevenness A.

In addition, using the epoxy resin compositions for optical semiconductor encapsulation obtained in Examples and Comparative Examples, after transfer molding at 150°C for 6 minutes, the surface was polished after further curing at 150°C for 3 hours. The surface roughness of the polished surface is 1.5 μm.
A runner-shaped flat plate (thickness: 3.0 mm, width: 5 recesses) having the following irregularities and a curved portion of 120° was prepared.

This runner is attached to the 1/2 inch built into the camera.
Presence or absence of a striped pattern in the image when mounted on an area sensor sealed body, which is an 80,000-pixel Quib solid-state image sensor, illuminated with strong parallel light with a luminous intensity of 10 candela at right angles, and stopped the aperture down to F-32. was determined. The presence or absence of the optical unevenness is also shown in the table as optical unevenness B. As a result, for example, no optical unevenness was observed in the product of Example 9. In the product of Example 1, slight optical unevenness was observed. In addition, Example 2~
Slight optical unevenness was observed in the 8 products as well, similar to the Example 1 product. As described above, slight optical unevenness was observed in the evaluation using optical unevenness B for the products of Examples 1 to 8, but no optical unevenness was observed in the evaluation based on optical unevenness A. There is virtually no problem even if an area sensor, which is a solid-state imaging device, is directly molded using an epoxy resin composition for encapsulating a semiconductor. Also,
In the evaluation of optical unevenness B in Comparative Example 1, optical unevenness was observed in its imaging, and optical unevenness was similarly observed in Comparative Examples 2 to 7.

From these results, it can be seen that the optical semiconductor device molded using the example product has excellent performance.

[Brief explanation of the drawing]

Figure 1 is a flow diagram of the resin composition during transfer molding using a conventional epoxy resin composition for encapsulating optical semiconductors, Figure 2 is a flow diagram of the main part of the resin composition, and Figure 3
The figure is a cross-sectional view of an optical semiconductor device resin-sealed with the epoxy resin composition for optical semiconductor sealing of the present invention. 16...Epoxy resin composition patent ratio I for optical semiconductor encapsulation
Director Nitto Denko Corporation

Claims (9)

[Claims] (1) A B-stage epoxy resin composition for encapsulating optical semiconductors in which the encapsulating resin contains an epoxy resin, a curing agent, and a curing accelerator, which are uniformly mixed into fine particles and have a maximum particle size of 30 μm or less. An optical semiconductor device comprising a cured product of a resin composition in which the ratio of particles of is set to 90% by weight or more. (2) A B-stage epoxy resin composition for encapsulating optical semiconductors containing an epoxy resin, a curing agent, and a curing accelerator as constituent components, which are uniformly pulverized and mixed, and have a maximum particle size of 30 μm.
An epoxy resin composition for encapsulating optical semiconductors, characterized in that the proportion of the following particles is set to 90% by weight or more. (3) Claim (2) wherein the epoxy resin composition for optical semiconductor encapsulation obtained by pulverization has a proportion of particles with a maximum particle size of 20 μm or less set to 90% by weight or more.
) The epoxy resin composition for encapsulating an optical semiconductor as described above. (4) Claim (2) wherein the epoxy resin composition for optical semiconductor encapsulation obtained by pulverization has a proportion of particles with a maximum particle size of 10 μm or less set to 90% by weight or more.
) The epoxy resin composition for encapsulating an optical semiconductor as described above. (5) A claim in which the epoxy resin composition for optical semiconductor encapsulation obtained by pulverization has a proportion of particles with a maximum particle size of 1.0 μm or less set to 90% by weight or more (
2) The epoxy resin composition for encapsulating an optical semiconductor as described above. (6) For optical semiconductor encapsulation, which is formed into a tablet by cold molding using the epoxy resin composition for optical semiconductor encapsulation according to any one of claims (2) to (5). Epoxy resin composition. (7) A method for manufacturing an optical semiconductor device, which comprises sealing an optical semiconductor element by transfer molding using the epoxy resin composition for optical semiconductor sealing according to any one of claims (2) to (6). . (8) The sealing resin is a B-stage thermosetting resin composition for encapsulating optical semiconductors containing a thermosetting resin and a curing agent as constituent components, which are uniformly pulverized and mixed, and have a maximum particle size of 30 μm.
An optical semiconductor device comprising a cured resin composition in which the proportion of the following particles is set to 90% by weight or more. (9) A B-stage thermosetting resin composition for encapsulating optical semiconductors containing a thermosetting resin and a curing agent as constituent components, which is uniformly pulverized and mixed, and the proportion of particles with a maximum particle size of 30 μm or less 1. A thermosetting resin composition for optical semiconductor encapsulation, characterized in that the content of the thermosetting resin composition is set at 90% by weight or more.