JPH06104768B2 - Light-transmissive epoxy resin composition and optical semiconductor device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention provides a cured product having high transparency and a small linear expansion coefficient, which is suitable for use in encapsulating an optical semiconductor device. The present invention relates to a composition and an optical semiconductor device sealed with a cured product of the composition.

[Problems to be Solved by Prior Art and Invention]

Conventionally, in order to protect precision electronic components such as semiconductor devices, these have been sealed with an epoxy resin.

Epoxy resins used for this purpose are required to have high properties such as low shrinkage, low expansion, heat resistance, and moisture resistance. Among these properties, low shrinkage and low expansion are semiconductor devices. It is important to prevent resin cracks and element destruction during encapsulation, and by mainly incorporating an inorganic filler into the epoxy resin, improvement of these low shrinkage ratio and low expansion is aimed at. .

However, when encapsulating optical semiconductor devices such as light-emitting and light-receiving elements with a transparent epoxy resin, in order not to impair their transparency, a filler is not usually added. All the coefficients are large, and there is a problem that resin is cracked or the element is broken when a large-sized light emitting element is sealed. On the other hand, a transparent epoxy resin composition in which a filler is mixed with an epoxy resin has also been proposed, but in the conventional composition, when trying to effectively prevent cracking of the resin or destruction of the element, the transparency becomes poor and the element becomes However, if it is attempted to maintain the transparency, the cracking of the resin and the destruction of the device cannot be effectively prevented.

Therefore, development of an epoxy resin composition having both transparency and low stress has been desired.

The present invention has been made in view of the above circumstances, and has a high transparency, a low shrinkage ratio, a low expansion coefficient, a light-transmissive epoxy resin composition that gives a cured product with low stress, and a cured product of the composition. It is an object to provide a sealed optical semiconductor device.

[Means and Actions for Solving the Problems]

The inventors of the present invention have conducted extensive studies in order to achieve the above object, and as a result, a curable epoxy resin composition containing a curable epoxy resin and a curing agent was used to measure 90% by the following linear transmittance measurement method A.
It has been found that it is effective to add silica-titania glass particles having a linear transmittance of 70% or more in the wavelength range of 0 nm to 600 nm.

A A bisphenol type epoxy resin represented by the following general formula (1) or a novolac type epoxy resin represented by the following general formula (2) is mixed with phenylglycidyl ether to obtain a silica-titania glass particle having a difference in refractive index. ± 0.00
Prepare a solution within 2. This solution has an average particle size of 5
Silica-titania glass particles crushed to -30 μm are mixed in a weight ratio of 1: 1 and the linear transmittance of the mixture is measured with an optical path length of 1 mm.

(However, n is an integer of 0 to 10.) (However, n is an integer of 0 to 10.) That is, the silica-titania glass particles have excellent light transmittance, and the difference in refractive index from the epoxy resin can easily be 0.01 or less. Therefore, when this silica-titania glass particles are blended with a light-transmissive epoxy resin composition, the cured product has a very good transparency, for example, a light transmittance of 750 nm at a thickness of 0.5 mm of 80% or more. Moreover, it has been found that, when used for encapsulation of an optical semiconductor device, it has a low shrinkage ratio and a low expansion property, and can effectively prevent cracking of the resin and breakage of the element, and thus achieved the present invention. .

Accordingly, the present invention is characterized by containing a curable epoxy resin, a curing agent, and silica-titania glass particles having a linear transmittance of 70% or more in the wavelength range of 900 nm to 600 nm according to the above measuring method A. Provided are a transparent epoxy resin composition and an optical semiconductor device encapsulated with a cured product of the composition.

Hereinafter, the present invention will be described in more detail.

The light transmissive epoxy resin composition of the present invention contains the curable epoxy resin composition containing a curable epoxy resin and a curing agent as described above, and the silica-titania glass particles.

Here, the curable epoxy resin composition is a mixture of an epoxy resin having two or more epoxy groups in one molecule with a curing agent and other various additives as necessary.
50% or more, especially 70%, light transmittance at 750 nm of cured product of m thickness
Those having transparency as described above are preferably used. In the present invention, the epoxy resin, the curing agent, and various additives are not particularly limited as long as the curable epoxy resin composition has such transparency.

For example, as the epoxy resin, it is sufficient if it can be cured by various curing agents described later, and the molecular structure,
The molecular weight and the like are not particularly limited, and various conventionally known epoxy resins can be used. Specific examples thereof include epoxy resins synthesized from various novolak resins such as epichlorohydrin and bisphenol, alicyclic epoxy resins, and epoxy resins having halogen atoms such as chlorine and bromine atoms introduced therein. The seeds may be used alone or in combination of two or more.

Commercially available products of such transparent curable epoxy resin include, for example, bisphenol type epoxy resin such as Epicoat 828, Epicoat 1001 (trade name, made by Yuka Shell Epoxy Co., Ltd.), Epicoat 1055K (trade name, made by Yuka Shell Epoxy Co., Ltd. RE310S, RE304S (both trade names, manufactured by Nippon Kayaku Co., Ltd.) and the like.

In addition to the epoxy resin having two or more epoxy groups in one molecule, a monoepoxy compound may be appropriately used in combination, and examples of the monoepoxy compound include styrene oxide, cyclohexene oxide, propylene oxide and methyl. Examples include glycidyl ether, ethyl glycidyl ether, phenyl glycidyl ether, allyl glycidyl ether, octylene oxide, dodecene oxide and the like.

Further, as a curing agent for epoxy resin, an amine type curing agent represented by diaminodiphenylmethane, diaminodiphenylsulfone, metaphenylenediamine, etc., and an acid anhydride type curing agent such as phthalic anhydride, pyromellitic dianhydride, benzophenone tetracarboxylic acid anhydride, etc. Examples thereof include agents or phenol novolac curing agents having two or more hydroxyl groups in one molecule such as phenol novolac and cresol novolac. Among these curing agents, acid anhydride type curing agents containing no aromatic ring such as hexahydrophthalic anhydride and tetrahydrophthalic anhydride are most preferable.

Further, in the present invention, various curing accelerators, for example, imidazole or a derivative thereof, a tertiary amine derivative, a phosphine derivative, a cycloamidine derivative and the like are used in combination for the purpose of accelerating the reaction between the curing agent and the epoxy resin. Does not matter at all.

In addition, the compounding amount of these curing agents and curing accelerators can be a usual dose.

The light-transmitting epoxy resin composition of the present invention is the above-mentioned curable epoxy resin composition containing the highly transparent silica-titania glass particles.

Here, as the silica-titania glass particles, those having a linear transmittance of 70% or more, preferably 80% or more in the wavelength range of 900 nm to 600 nm according to the linear transmittance measuring method A described below are used.

A A bisphenol type epoxy resin represented by the following general formula (1) or a novolac type epoxy resin represented by the following general formula (2) is mixed with phenylglycidyl ether to obtain a silica-titania glass particle having a difference in refractive index. ± 0.00
Prepare a solution within 2. This solution has an average particle size of 5
Silica-titania glass particles crushed to -30 μm are mixed in a weight ratio of 1: 1 and the linear transmittance of the mixture is measured with an optical path length of 1 mm.

(However, n is an integer of 0 to 10.) (However, n is an integer of 0 to 10.) The silica-titania glass particles are refracted with a cured product of the curable epoxy resin in order to minimize light scattering when blended with the curable epoxy resin. It is desirable that the rate difference be within ± 0.01, preferably within ± 0.005, and more preferably within ± 0.002.

The method for producing the silica-titania glass particles according to the present invention can be carried out according to the method described in Japanese Patent Application No. 2-28077.

That is, first, as starting materials, silicon alkoxides such as Si (OCH ₃ ) ₄ and Si (OC ₂ H ₅ ) ₄ and Ti (OC ₃ H ₇ ) ₄ , Ti (OC ₄
A titanium alkoxide such as H ₈ ) ₄ is used. In this case, TiO ₂ is 10 to 18 mol% based on the total of SiO ₂ and TiO _2.
It is preferable to use silicon alkoxide and titanium alkoxide in such an amount that If the content of TiO ₂ does not reach 10 mol%, the silica-titania glass particles obtained may not have a refractive index of 1.53 or more, which is considered to be preferable as a filler for epoxy resin, while 18 mol% may be used. If it exceeds, it may be difficult to obtain a transparent epoxy resin having the same refractive index as that of the silica-titania glass particles.

As a method for obtaining a sol or gel from these raw materials, the above silicon alkoxide and titanium alkoxide are dissolved in an alcohol such as methanol, ethanol or propanol as a diluent solvent, and water is added to this to hydrolyze the silica. After the titania sol is prepared, the sol is transferred to a container for gelation, sealed, and then allowed to stand in a thermostatic dryer to gel. In this case, regarding the gelation temperature and the aging temperature after gelation, if the temperature is lower than 60 ° C., the hydrolysis of the alkoxide may be incomplete, which causes coloring in the sintering step described later. Since the trivalent Ti ions are easily generated, the gelation and aging temperature is preferably 60 ° C. or higher. The aging is carried out for 1 hour or longer, preferably 5 hours or longer, in order to complete the hydrolysis.

Next, the method of drying the gelled and aged wet gel is not particularly limited. For example, the lid of the closed container used for aging the gel is removed, and the gel is left as it is in a constant temperature oven to dry. The method of obtaining a dry gel can be adopted.

Further, the dry gel thus obtained is crushed and then sintered.

Here, the crushing method is not particularly limited, the particle size is appropriately selected, and an appropriate crushing method and particle size can be adopted according to the application, but the average particle size is 1 to 100 μm, particularly 5 to 30 μm It is preferable.

Finally, the crushed dry gel is sinter-vitrified, but it is preferable that the sinter temperature is in the range of 1050-1250 ° C.
When the sintering temperature is less than 1050 ° C., the particles are not completely and uniformly densified, and therefore, when the transmittance of the silica-titania glass particles is measured, the light incident on the inside of the particles is the silica-titania glass constituent particles and its particles. Because of the scattering due to the difference in refractive index between the pores of the constituent particles, it may be possible to obtain a low transmittance value as a result. At a sintering temperature higher than 1250 ° C, precipitation of the Anatase phase, which is one of the crystalline phases of TiO ₂ , occurs, so silica-titania glass particles with excellent light transmittance are obtained even in this temperature range. It may not be possible.

Incidentally, this sintering method may be within the above temperature range,
Although not particularly limited, it is possible to use a sintering furnace, such as an electric furnace, which maintains a constant temperature, and introduce air, oxygen gas, or a mixed gas of oxygen and air into the furnace to create an oxidizing atmosphere in the furnace. It is preferable in preventing the generation of trivalent Ti ions which causes coloring. In addition, the rate of temperature increase until reaching the specified temperature is usually
It is preferably 10 to 500 ° C./hour. The sintering time is usually 10 to 300 minutes in the above temperature range.

The silica-titania glass particles thus obtained have a high light transmittance, and moreover, the refractive index can be easily made equal to that of the epoxy resin by changing the above-mentioned TiO ₂ content. Measurement method A
70% linear transmittance in the wavelength range of 900nm to 600nm
As described above, it is extremely excellent in transparency.

It is also effective to preliminarily treat the surfaces of the silica-titania glass particles with carbon functional silane or the like.

The blending amount of the silica-titania glass particles according to the present invention is preferably 10 to 600 parts by weight, and particularly preferably 50 to 300 parts by weight, based on 100 parts by weight of the curable epoxy resin composition. If the amount is less than 10 parts by weight, the effect of imparting low shrinkage and low expansion may not be sufficiently exhibited, while if the amount is more than 600 parts by weight, the viscosity of the composition may be too high.

The light-transmissive epoxy resin composition of the present invention is a uniform mixture of the above-mentioned curable epoxy resin composition and a predetermined amount of silica-titania glass particles using a mixing device such as various mixers, kneaders, rolls and extruders. It can be obtained by kneading, but in addition to this, various low-stress agents, release agents, visible light-cutting agents, antioxidants, flame retardants, and carbon, if necessary, within a range that does not impair transparency. An appropriate amount of functional silane or the like can be added. There is no limitation on the mixing order of these components, but when a part or all of the curable epoxy resin composition is solid,
It is effective to preliminarily heat-melt and mix with all or a part of the required components, or a method of dissolving in a solvent and then uniformly mixing, and then stripping the solvent can also be adopted. .

The light-transmitting epoxy resin composition of the method thus obtained is an epoch-making one having both transparency and low stress,
It is suitable for sealing optical semiconductor devices. In this case, conventionally used molding methods such as transfer molding, injection molding, and casting method can be used to seal the optical semiconductor device such as the LED. The molding temperature is 120-180 ℃, and the post cure is 120-180 ℃.
12 hours is preferable.

〔The invention's effect〕

As described above, the light-transmissive epoxy resin composition of the present invention contains the silica-titania glass particles having good transparency, so that the cured product has good transparency and a low shrinkage ratio. Since it has a low expansion coefficient and low stress, it is preferably used for encapsulation of an optical semiconductor device, and an optical semiconductor device encapsulated with such a light-transmissive epoxy resin composition has effective optical functionality. It has excellent reliability as well as performance.

Hereinafter, the present invention will be specifically described by showing Examples and Comparative Examples, but the present invention is not limited to the following Examples.

First, the silica-titania glass particles used in Examples and Comparative Examples were manufactured as follows.

[Production example]

Silica-titania glass particles A To a solution of 2083.3 g of ethyl orthosilicate (manufactured by Tama Chemical Industry Co., Ltd.) and 672.6 g of ethanol (Wako Pure Chemical Industries, special grade), 180 ml of 0.2 N hydrochloric acid aqueous solution was added at 30 ° C., and the mixture was stirred for 1 hour. 505.7 g of titanium tetraisopropoxide (Wako Pure Chemical, first grade) was gradually added thereto, and the mixture was further stirred for 1 hour. afterwards,
668.1 g of pure water was added, and the mixture was further stirred for 10 minutes. Got
When the TiO ₂ —SiO ₂ sol was placed in a polypropylene container and sealed at 90 ° C., the sol gelled after about 30 minutes. The gel was aged as it was for 12 hours under the sealed at 90 ° C. Then, the lid of the container was removed and the product was dried in a dryer at 70 ° C. for 4 days to obtain a dry gel body.

250 g of this dried gel body was crushed for 1 hour with a ball mill made of alumina having a volume of 2 liters. Put the dried gel body after crushing in a box-type electric furnace and dry it up to 1100 ° C under the condition of 1.4 m ³ / h of dry air.
The temperature is raised for 1 hour and kept at 1100 ℃ for 30 minutes, and the average particle size is 23.9
μm TiO ₂ —SiO ₂ particles (sintered glass) were obtained.

When the refractive index (n _p ) of this TiO ₂ —SiO ₂ sintered glass was measured by the liquid immersion method, it was 1.561.

Silica-titania glass particles B The dry gel obtained in the example was placed in a box-type electric furnace and heated to 1000 ° C. for 13 hours under the condition of dry air of 1.4 m ³ / h, and for 30 minutes.
740g of colorless and transparent TiO ₂ -SiO ₂ sintered glass kept at 1000 ℃
Got

This sintered glass was crushed in the same manner as in Example to have an average particle size of 18.7.
μm TiO ₂ —SiO ₂ glass particles were obtained.

The transmittance and particle size distribution of these TiO ₂ —SiO ₂ glass particles were measured by the following methods. The results are shown in Table 1.

The TiO ₂ -SiO ₂ particles measuring methods mean particle size 5~30μ transmittance, Epikote 828 (Yuka adjusting the mixing ratio to be in the range of ± 0.002 in the refractive index calculated from the content of TiO ₂ (Epoxy resin manufactured by Shell Epoxy Co., Ltd.) and phenyl glycidyl ether are mixed in a mixed solution (refractive index (n ²⁵ _D ) = 1.5612) at a weight ratio of 1: 1. After sufficiently dispersing the particles, degassing under reduced pressure is performed until no bubbles are visually observed. This mixture
Place it in a cell with an optical path length of 1 mm and use a spectrophotometer to
The transmittance spectrum is measured in the wavelength range of 00 nm to 400 nm. In this case, the reference is blank.

Measurement method of particle size distribution A 0.2% by weight aqueous solution of sodium hexametaphosphate was used as a dispersion medium of the sample, and the particle size distribution was measured by a centrifugal sedimentation type particle size distribution analyzer SA-CP3L manufactured by Shimadzu.

[Examples 1 and 2 and Comparative Example] Epicoat 828 17.5 parts by weight, Epicoat 1001 50.3 parts by weight (above, bisphenol A type epoxy resin, trade name,
Yuka Shell Epoxy Co., Ltd.), hexahydrophthalic anhydride (New Nippon Rika, trade name, RIKACID HH) 32.2 parts by weight,
0.5 parts by weight of γ- (glycidylpropyl) trimethoxysilane Silica-titania glass particles A and B obtained above were blended in the amounts shown in Table 2, melt-mixed at 70 ° C. for 30 minutes, and then mixed with 2-phenyl. Add 0.5 parts by weight of imidazole, 70 ℃
Were mixed for 10 minutes to prepare three kinds of light transmissive epoxy resin compositions. A light-transmissive epoxy resin composition was prepared in the same manner except that silica-titania glass particles were not added.

The glass transition temperature, linear expansion coefficient, crack resistance, and light transmittance of these compositions were measured by the methods described below. The results are also shown in Table 2.

Expansion coefficient, glass transition temperature A test piece of 4 mmφ × 15 mm was molded from the above-mentioned light-transmitting epoxy resin composition, and the value when the temperature was raised at a rate of 5 ° C./min by a dilatometer was measured using the test piece. .

Crack resistance 9.0 × 4.5 × 0.5mm size silicon chip 14PIN-1C
It is adhered to a frame (42 alloy), and the above-mentioned light-transmissive epoxy resin composition is molded under the molding conditions of 150 ° C. for 5 minutes.
After after-curing at 50 ℃ for 4 hours, add -40 ℃
A thermal cycle of (30 minutes) to 150 ° C. (30 minutes) was repeatedly added, and the resin crack occurrence rate after 500 cycles was examined (n = 10).

A light-transmittance molded article having a thickness of 1 mm was molded and the light-transmittance at 700 nm was measured.

From the results shown in Table 2, the cured product of the curable epoxy resin composition (Comparative Example 1) containing no silica-titania glass particles has a large linear expansion coefficient, and therefore has very poor crack resistance. The cured product of the composition (Comparative Example 2) in which silica-titania particles having a light transmittance of 30% or less was added to the composition had a small linear expansion coefficient and improved crack resistance, but on the other hand, the light transmittance was It will be greatly reduced. On the other hand, the cured product of the light-transmitting composition of the present invention (Examples 1 and 2) having a light transmittance of 70% or more of silica-titania particles reduces the linear expansion coefficient of the epoxy resin, It can be seen that the crack resistance can be greatly improved and that the transparency of the epoxy resin is not impaired even if a large amount is compounded.

Continuation of front page (51) Int.Cl. ⁵ Identification number Office reference number FI Technical indication location H01L 21/312 Z 7352-4M 23/29 23/31 (72) Inventor Kazuhiro Arai Gunma prefecture Annaka city Isobe 2 1-chome 13-1 Shin-Etsu Chemical Co., Ltd. Silicon Silicon Electronic Materials Research Laboratory (72) Inventor Masatoshi Takita No. 28 Nishifukushima, Chugaku-mura, Nakakubiki-gun, Niigata 1 Shin-Etsu Chemical Co., Ltd. ) Reference JP 61-91242 (JP, A) JP 64-86539 (JP, A) JP 2-263846 (JP, A) JP 3-232741 (JP, A)

Claims (2)

[Claims] 1. A curable epoxy resin, (b) a curing agent, and (c) 900 nm to 600 nm according to the following linear transmittance measurement method A.
And a silica-titania glass particle having a linear transmittance in the wavelength range of 70% or more. A A bisphenol type epoxy resin represented by the following general formula (1) or a novolac type epoxy resin represented by the following general formula (2) is mixed with phenylglycidyl ether to obtain a silica-titania glass particle having a difference in refractive index. ± 0.00
Prepare a solution within 2. This solution has an average particle size of 5
Silica-titania glass particles crushed to -30 μm are mixed in a weight ratio of 1: 1 and the linear transmittance of the mixture is measured with an optical path length of 1 mm. (However, n is an integer of 0 to 10.) (However, n is an integer of 0 to 10.) 2. An optical semiconductor device encapsulated with a cured product of the light-transmissive epoxy resin composition according to claim 1.