JP5090404B2 - Manufacturing method of resin tablet for optical semiconductor sealing, resin tablet for optical semiconductor sealing obtained thereby, and optical semiconductor device using the same - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a method for producing an optical semiconductor sealing resin tablet, an optical semiconductor sealing resin tablet obtained thereby, and an optical semiconductor device using the same.

  2. Description of the Related Art Conventionally, an optical semiconductor element is generally sealed and formed into a device by a ceramic package or a plastic package. However, since the ceramic package is relatively expensive in terms of constituent materials and is inferior in mass productivity, the use of plastic packages has recently become the mainstream. In particular, performing transfer molding using a raw material obtained by tableting the epochine resin composition in advance into a tablet shape is excellent in terms of workability at the time of molding, mass productivity, and reliability after molding.

  However, the epoxy resin composition for sealing an optical semiconductor does not react easily because the components of the epoxy resin, the curing agent, and the curing accelerator are relatively difficult to disperse and it is not easy to uniformly mix and disperse the whole. There is a problem that it becomes uniform and molding irregularities and molding reaction voids are likely to occur. Then, due to these unevenness and voids, there is a problem that optical unevenness occurs and the reliability of the optical semiconductor device is impaired.

  Therefore, by using a finely pulverized epoxy resin composition, uniform dispersion of the composition is ensured, and the above-mentioned molding unevenness and molding reaction void are eliminated or greatly improved to reduce optical unevenness. A technique (see Patent Document 1) has been proposed.

JP-A-3-3258

  Certainly, a finely pulverized epoxy resin composition is excellent in uniform dispersibility and has an excellent effect in eliminating optical unevenness. However, since the particle size is small, tableting properties are poor, and there are various problems such as poor appearance of the tablet (chips, cracks, top and bottom gaps, etc.), generation of defective products due to weight variations, collapse during handling, etc. Therefore, the improvement is strongly desired.

  The present invention has been made in view of such circumstances, and a resin tablet for encapsulating an optical semiconductor that can obtain a high-quality tablet with high yield by tableting molding using a fine powder epoxy resin composition. It is an object of the present invention to provide an optical semiconductor sealing resin tablet obtained thereby and an optical semiconductor device using the same.

  In order to achieve the above object, the present invention provides a step of preparing a fine powdery epoxy resin composition having an average particle size of 50 to 200 μm containing an epoxy resin, a curing agent and a curing accelerator, and the fine powdery epoxy The resin composition was provided with a step of obtaining a granular epoxy resin composition having an average particle size of 500 to 1800 μm by passing through a granulation step, and a step of tableting the granular epoxy resin composition into a tablet. The manufacturing method of the resin tablet for optical semiconductor sealing is a 1st summary.

  In addition, among the above, the present invention, in particular, in the granulation step, after the fine powder epoxy resin composition is granulated into a coarse granular epoxy resin composition, the average particle size is passed through the granulation step. The manufacturing method of the resin tablet for optical semiconductor sealing which obtained the granular epoxy resin composition of diameter 500-1800 micrometers is made into the 2nd summary, and the process of preparing the said fine powder epoxy resin composition especially among them The third gist is a method for producing an optical semiconductor sealing resin tablet in which a pulverized epoxy resin composition having an average particle size of 500 to 1000 μm is finely pulverized by a turbo mill.

  And this invention is the resin tablet for optical semiconductor sealing obtained by the manufacturing method which is the summary of any one of said 1st-3rd, Comprising: Average particle diameter 50 containing an epoxy resin, a hardening | curing agent, and a hardening accelerator A resin tablet for encapsulating an optical semiconductor formed into a tablet in a state where a fine powdery epoxy resin composition of ~ 200 μm is granulated into granules having an average particle diameter of 500 to 1800 μm To do.

  Furthermore, this invention makes the 5th summary the optical-semiconductor device formed by sealing an optical semiconductor element using the resin tablet for optical-semiconductor sealing which is the said 4th summary.

  That is, the present inventors are an epoxy resin composition for encapsulating optical semiconductors, and even when prepared to a fine powder having an average particle size of 50 to 200 μm, it is good without causing breakage or cracking. Intensive research was conducted on the method of tableting. As a result, if a fine powder is not directly compressed and molded, but once granulated to a relatively large particle size and then tableted, a good tablet that is not brittle and can be obtained with a high yield is obtained. And the present invention has been reached.

  In the present invention, the “average particle size” means an average particle size measured using a laser diffraction / scattering particle size distribution measuring apparatus.

  According to the method for producing an optical semiconductor encapsulating resin tablet of the present invention, after finely pulverizing a fine powdery epoxy resin composition having an average particle size of 50 to 200 μm into a large particle size. For tableting, tableting can be performed satisfactorily without chipping or cracking while maintaining a finely and uniformly dispersed state of the finely divided epoxy resin composition.

  Among the above-mentioned production methods, in particular, in the granulation step, the fine powder epoxy resin composition is granulated into a coarse granular epoxy resin composition and then passed through the granulation step. Since the particle size distribution of the granular epoxy resin composition to be obtained can be set with high accuracy in the sizing step, a better result can be obtained.

  Further, among the above production methods, in particular, in the step of preparing the fine powder epoxy resin composition, when the pulverized epoxy resin composition having an average particle size of 500 to 1000 μm is finely pulverized by a turbo mill, it is efficient and uniform. A fine powder can be obtained and is suitable.

  And the resin tablet for sealing an optical semiconductor obtained by the above production method of the present invention is formed by compressing and molding a fine powder epoxy resin composition at a high density, resulting in poor appearance such as chipping and cracking, and shape retention. Since there is no defect or weight variation, it is excellent in terms of workability, mass productivity, and reliability after molding when used as a resin raw material for sealing an optical semiconductor element by transfer molding.

  Moreover, the optical semiconductor device in which the optical semiconductor element is sealed using the resin tablet for optical semiconductor sealing of the present invention is sealed with a uniform reaction cured body derived from a fine powder epoxy resin composition. Therefore, there is no optical unevenness, and it is highly reliable and of high quality.

(A)-(d) is explanatory drawing of the manufacturing method of the resin tablet for optical semiconductor sealing which is one embodiment of this invention. It is typical explanatory drawing of the dry-type compression granulator used for one embodiment of the above-mentioned present invention. It is a diagram explaining the change of the particle size distribution of the epoxy resin composition in one embodiment of the said invention.

  First, 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. A filler such as silica powder is not used because it impairs light transmission.

  As the above-mentioned epoxy resin, those with little coloring are preferable. For example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenol novolac type epoxy resin, alicyclic epoxy resin, triglycidyl isocyanate, hydantoin epoxy and other heterocyclic rings Examples thereof include epoxy resins, water-added bisphenol A type epoxy resins, aliphatic epoxy resins, glycidyl ether type epoxy resins and the like. These may be used alone or in combination of two or more.

  As the curing agent, an acid anhydride that is less colored on the cured product of the resin composition at the time of curing or after curing is suitable. Examples thereof include phthalic anhydride, maleic anhydride, trimellitic anhydride, pyromellitic anhydride, hexahydrophthalic anhydride, tetrahydrophthalic anhydride, methyl nadic anhydride, nadic anhydride, glutaric anhydride, and the like. Other curing agents include amine curing agents such as metaphenylenediamine, dimethyldiphenylmethane, diaminodiphenylsulfone, m-xylenediamine, tetraethylenepentamine, diethylamine, propylamine, and phenol resin curing agents. can give. These may be used alone or in combination of two or more.

  Examples of the curing accelerator include tertiary amines such as triethanolamine, imidazoles such as 2-methylimidazole, organophosphorus compounds such as tetraphenylphosphonium / tetraphenylborate, triphenylphosphine, 1,8- And diazabicycloalkene compounds such as diazabicyclo [5,4,0] undecene-7 and 1,5-diazabicyclo [4,3,0] nonene-5. These may be used alone or in combination of two or more.

  In addition to the above-described components, additives such as a coloring inhibitor, a lubricant, a modifier, a deterioration inhibitor, and a release agent are used in the epoxy resin composition for sealing an optical semiconductor as necessary.

  Examples of the anti-coloring agent include phenolic compounds, amine compounds, organic sulfur compounds, and phosphine compounds.

  Examples of the lubricant include waxes such as stearic acid, magnesium stearate, and calcium stearate, and talc. In addition, when mix | blending the said lubricant agent, the compounding quantity is suitably set according to tableting molding conditions, For example, it can set to 0.1 to 0.4 weight% of the whole resin composition. Is preferred.

  The resin tablet for encapsulating an optical semiconductor of the present invention can be produced using these components, for example, as follows. That is, first, the above component raw materials are mixed and heated to form a molten resin, and then cooled, solidified and pulverized to produce a B-stage (semi-cured) epoxy resin composition for optical semiconductor encapsulation. A pulverized product is obtained.

  Examples of the pulverization method include pulverization using a ball mill. At this time, the pulverized product is preferably set to have an average particle size of 500 to 1000 μm, particularly 500 to 800 μm, in order to smoothly perform the next pulverization step. This pulverized product is a collection of relatively large pulverized pieces as schematically shown in FIG.

  Next, the pulverized product is finely pulverized using a turbo mill or the like to form a fine powder having an average particle size of 50 to 200 μm. This fine powder is fine as shown schematically in FIG. In particular, fine pulverization using the above-described turbo mill is preferable because it can efficiently obtain uniform fine powder.

  Then, the fine powder is granulated using a dry compression granulator or the like. At this time, it is preferable to first make a relatively large coarse particle (average particle diameter of about 2000 to 4000 μm) and then pass through a sizing step to form a particle having an average particle diameter of 500 to 1800 μm. For example, as schematically shown in FIG. 1 (c), the coarse granular material is obtained by compression-molding the fine powder into a plate shape without using a binder, and the fine powder is irregular. It gathers in the shape of the shape and prevents fine powder from scattering.

  In addition, the coarse-grained product is sized so that, for example, as shown schematically in FIG. 1 (d), an irregular shape of the coarse-grained material is arranged, the shape of the particles is uniform, and extremely large particles. In addition, since extremely small particles are excluded and the particles have an appropriate average particle size (500 to 1800 μm), the packing density during tableting can be increased. And each granular material is comprised with the fine powder by which the reaction state was equalized similarly to the coarse granular material of the previous step.

  Therefore, in the granular epoxy resin composition, each granular material is composed of fine powder with a uniform reaction state, and the average particle size of the granular material is large, so that the tableting moldability is improved. No chipping, cracking or weight variation occurs during tableting.

  And the tablet obtained by carrying out tableting using the said granular epoxy resin composition does not produce a chip | tip, a crack, and weight dispersion | variation as above-mentioned, and turns into a high quality tablet.

  And the optical semiconductor device formed by sealing the optical semiconductor element by transfer molding using the tablet as a resin raw material is sealed with a uniform reaction cured body derived from a fine powder epoxy resin composition. As a result, there is no optical unevenness, and the reliability is high and the quality is high. Accordingly, when an image is obtained by operating this optical semiconductor device, there is an advantage that a sharp image is obtained without causing a stripe pattern due to optical unevenness.

  If the average particle size of the finally obtained granular epoxy resin composition is less than 500 μm, the effect of improving tableting moldability by granulation is poor, and conversely, if the average particle size exceeds 1800 μm, the tableting moldability Although there is no problem, when the particles are large and used for sealing an optical semiconductor, voids and curing defects may occur, causing optical unevenness, which is not practical.

  Moreover, since the said granular epoxy resin composition is used for resin sealing of optical semiconductor elements, such as a light receiving element, a transparent thing is preferable from an optical viewpoint. In this case, “transparent” means that the cured product of the granular epoxy resin composition has a transmittance of 98% or more at 400 nm.

  Furthermore, in the production of the above granular epoxy resin composition, a dry compression granulator and a granulator are used in combination. However, recent dry compression granulators themselves have a granulation function. It is preferable to use such a type. A typical configuration thereof is schematically shown in FIG.

  This apparatus includes a hopper 1 for supplying a raw material, a screw / paddle part 3 for pushing the raw material into a pair of two rolling rolls 2 provided on the downstream side, and a plate compressed between the rolling rolls 2. A pulverizer 4 for pulverizing a molded product taken out into a coarse shape and a granulator 5 for sizing the obtained coarse granular material are provided. 6 is a decompression unit.

  According to this apparatus, after obtaining a desired coarse granular material by the pulverizer 4, a granular epoxy resin composition having a target average particle diameter can be obtained by the granulator 5.

  In addition, in the above-mentioned series of manufacturing methods, an example of the particle size distribution A of the fine powder before granulation, the particle size distribution B of the coarse particles, and the particle size distribution C of the final granulated particles is shown in FIG. . However, each particle size distribution is confirmed by a JIS standard sieve. According to this figure, a fine powder having an average particle size of 100 μm becomes a coarse granular material having an average particle size of 2000 to 4000 μm, and by passing through a sizing process, the average particle size of 750 μm with a gentle particle size distribution is obtained. It turns out that it becomes a granulated product.

  However, in the present invention, the fine powder of the epoxy resin composition is first made into a coarse granular product in the granulation step, and then it is not always necessary to make the granular epoxy resin composition in the granulating step. The granulated epoxy resin composition having an average particle diameter of 500 to 1800 μm may be directly granulated without going through the granulating step. This is because good tableting moldability and uniform dispersibility of the composition can be ensured as long as the average particle size of the obtained granular material does not exceed 1800 μm.

  Moreover, in the said manufacturing method, the fine powdery epoxy resin composition with an average particle diameter of 50-200 micrometers used as a raw material is easy to absorb moisture, and if it absorbs moisture, it will cause the problem that the glass transition temperature of the hardened | cured material of an epoxy resin composition falls. Therefore, it is preferable to carry out in an environment with little moisture such as in a dry air flow.

  Furthermore, the conditions for tableting the tablet using the granular epoxy resin composition are appropriately adjusted according to the composition, average particle size, particle size distribution, etc. of the granular epoxy resin composition. The compression rate at the time of tablet molding is preferably set to 90 to 96%. That is, if the compressibility value is less than 90%, the density of the tablet may be reduced and it may be easily cracked. Conversely, if the compressibility value is greater than 96%, cracks may occur during tableting and release. This is because chipping or breakage may occur during molding.

  Next, examples will be described together with comparative examples. However, the present invention is not limited to the following examples.

[Example 1]
The following raw materials were heated and dissolved at the following ratio, mixed, cooled, solidified and pulverized to produce a B-stage epoxy resin composition for optical semiconductor encapsulation having an average particle size of 500 to 800 μm.

<Composition a of epoxy resin composition>
Bisphenol A type epoxy resin (epoxy equivalent 650) 60 parts by weight Alicyclic epoxy resin (manufactured by Daicel Chemical Industries, EHPE-3150) 40 〃
Hardener: Tetrahydrophthalic anhydride 36 〃
Catalyst: Dimethylbenzamine 1.2 〃
Stearic acid 0.1 〃

  Next, this B stage-like epoxy resin composition for encapsulating an optical semiconductor is pulverized by a turbo mill (T250-4JS, manufactured by Turbo Kogyo Co., Ltd.) to obtain a fine powder epoxy resin composition having an average particle size of 100 μm. Obtained.

  Then, the fine powdery epoxy resin composition is applied to a roller compactor (manufactured by Turbo Kogyo Co., Ltd., WP160 × 60N1 type), natural degassing, screw rotation speed 48 rpm, rolling roll water cooling, and a coarse particle having an average particle diameter of 2000 to 4000 μm. A granular epoxy resin composition was obtained.

  Then, the above-mentioned coarse granular epoxy resin composition is granulated and sized by a roll granulator (manufactured by Nippon Granulator Co., Ltd., test machine: Model 1531). A composition was obtained. And 1000 resin tablets for optical semiconductor sealing of the compressibility as shown in Table 1 were formed by tableting the obtained resin composition for optical semiconductor sealing using a No. 20 rotary tableting machine. Obtained.

[Examples 2 to 9, Comparative Examples 1 and 2]
In the process of producing the resin composition for sealing an optical semiconductor, the average particle size was changed as shown in Tables 1 and 2 below. Moreover, it adjusted so that tableting shaping | molding might be made in the best state by changing the compounding quantity of a stearic acid as needed. Other than that, it was the same as in Example 1 above.

And with respect to all the obtained pieces, the presence or absence of chipping, cracks, brittleness, erosion, and weight variation were confirmed and evaluated as follows. And those results and comprehensive judgment were combined with the following Table 1 and Table 2, and were shown.
◎… All numbers are good.
○ The defect rate is 30% or less.
Δ: The defect rate exceeds 30%.
X: Total number is poor.

  From the above results, it can be seen that all of the products of Examples 1 to 9 have almost no appearance defects and weight variations, and a high-quality resin tablet for sealing an optical semiconductor can be obtained by tableting. On the other hand, the product of Comparative Example 1 could not be tableted. In addition, since the product of Comparative Example 2 was not a fine powder, it could be tablet-molded, but a lot of chipping, cracking and punching occurred.

  Next, using the optical semiconductor sealing resin tablet obtained in Examples 1 to 9, the camera was assembled using what was actually obtained by direct molding of the area sensor, which is a solid-state imaging device, and strong against it. An image obtained when parallel camera (10 candela) was applied and the aperture of the camera was reduced to F-32 was displayed on the display screen. As a result, no optical unevenness was observed in the images of any of the examples. Therefore, it can be seen that the optical semiconductor device in which the optical semiconductor element is sealed using the products of these examples is not affected by the optical unevenness and has excellent performance.

[Examples 10-14, Comparative Examples 3-6]
The optical semiconductor sealing resin composition of the following composition b was prepared with the optical semiconductor sealing resin composition of the said composition a.
<Composition b of epoxy resin composition>
Triglycidyl isocyanate 105 parts by weight Neopentyl glycol 20 〃
Curing agent: 4-methylhexahydrophthalic anhydride 158〃
Catalyst: Tetra-n-butylphosphonium O, O-diethyl phosphorodithioate
1.2 〃
Stearic acid 0.4 〃

  And the manufacturing process and the magnitude | size of the final average particle diameter were changed as shown in Table 3 and Table 4 using the resin composition for optical semiconductor sealing of the said composition a or the composition b. Moreover, it adjusted so that tableting shaping | molding might be made in the best state by changing the compounding quantity and compression rate of a stearic acid as needed. Other than that was carried out similarly to the said Example 1, and obtained the resin composition for optical semiconductor sealing of the target granular form or powder form (a fine powder form is included). And tableting molding was performed using No. 19 rotary tableting machine, and 1000 pieces of resin tablets for optical semiconductor sealing were obtained for each example. These were also evaluated in the same manner as described above by confirming the presence or absence of chipping, cracks, brittleness, and chipping, and weight variation. And those results and comprehensive judgment were combined with the following Table 3 and Table 4, and were shown.

  From the above results, it can be seen that the products of Examples 10 to 14 are almost free from appearance defects and weight variations, and a high-quality resin tablet for sealing an optical semiconductor can be obtained by tableting. On the other hand, Comparative Examples 3 and 5 could not be tableted. Further, since Comparative Examples 4 and 6 were not fine powders, they could be tablet-molded, but relatively many cracks, punches, etc. occurred.

  Next, using the resin tablet for encapsulating optical semiconductors obtained in Examples 10 to 14, the camera was assembled using what was actually obtained by direct molding of the area sensor, which is a solid-state imaging device, and strong against it. An image obtained when parallel camera (10 candela) was applied and the aperture of the camera was reduced to F-32 was displayed on the display screen. As a result, no optical unevenness was observed in the images of any of the examples. Therefore, it can be seen that the optical semiconductor device in which the optical semiconductor element is sealed using the products of these examples is not affected by the optical unevenness and has excellent performance.

  INDUSTRIAL APPLICATION This invention can be utilized for the manufacturing method of the resin tablet for optical semiconductor sealing used for sealing of an optical semiconductor element, the resin tablet for optical semiconductor sealing obtained by it, and an optical semiconductor device using the same. .

Claims (5)

  By preparing a fine powdery epoxy resin composition having an average particle size of 50 to 200 μm containing an epoxy resin, a curing agent and a curing accelerator, and passing the fine powdery epoxy resin composition through a granulation step A resin tablet for encapsulating an optical semiconductor, comprising: a step of obtaining a granular epoxy resin composition having an average particle size of 500 to 1800 μm; and a step of tableting the granular epoxy resin composition into a tablet shape. Manufacturing method.   In the granulation step, the fine powder epoxy resin composition is granulated into a coarse granular epoxy resin composition and then passed through a granulation step, thereby obtaining a granular epoxy resin composition having an average particle size of 500 to 1800 μm. The manufacturing method of the resin tablet for optical semiconductor sealing of Claim 1 which was made to do.   3. The optical semiconductor encapsulating resin according to claim 1, wherein in the step of preparing the fine powder epoxy resin composition, the pulverized epoxy resin composition having an average particle diameter of 500 to 1000 μm is finely pulverized by a turbo mill. Tablet manufacturing method.   A resin tablet for sealing an optical semiconductor obtained by the production method according to any one of claims 1 to 3, wherein the fine tablet has an average particle size of 50 to 200 µm and contains an epoxy resin, a curing agent, and a curing accelerator. A resin tablet for encapsulating an optical semiconductor, wherein the epoxy resin composition is granulated into a tablet having a mean particle size of 500 to 1800 μm. An optical semiconductor device formed by sealing an optical semiconductor element using the resin tablet for optical semiconductor sealing according to claim 4.

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