JP2003197830A - Optical semiconductor sealing unsaturated polyester resin composition, and optical semiconductor device sealed therewith - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical semiconductor sealing unsaturated polyester resin composition superior in transparency in low wavelength lights, an ultraviolet rays resistance deterioration, resistance solder properties; and to provide an optical semiconductor device sealed with the cure matter. <P>SOLUTION: In an optical semiconductor sealing unsaturated polyester resin composition and an optical semiconductor device sealed with the cure matter, an unsaturated polyester resin composition is obtained by polymerizing an unsaturated acid component (a) selected from a maleic acid, a fumaric acid, and an anhydride thereof; and a diol component (b) selected from an aliphatic or alicyclic dihydric alcohol, and includes an unsaturated polyester resin of 100 parts by weight which includes α,β-ethylene unsaturated radical derived from the (a) component of 1 mol or more per weight 1 kg; and an organic peroxide (B) of 0.1 to 10 parts by weight. A light transmissivity is 90% or more in an optical path length 1 mm in an area of wavelength 380 to 400 nm and a softening point is 55°C to 120°C. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an unsaturated polyester resin composition for encapsulating an optical semiconductor and an optical semiconductor device encapsulated with the unsaturated polyester resin composition.

[0002]

2. Description of the Related Art Conventionally, optical semiconductor elements have been developed mainly for infrared rays, red, yellow, and green, but by the development of new light emitting elements, efficient light rays of short wavelengths such as blue and white can be generated. LEDs that emit light have been put to practical use. These LE
The resin used for sealing D is required to have not only the conventional visible light transmittance, that is, the apparent transparency, but also the transmittance for the near-ultraviolet light secondary to the device. this is,
The light of short wavelength is originally invisible to the eyes and is in a wavelength range where transparency is not required, but the absorption of the light of this wavelength by the resin causes deterioration of physical strength due to photolysis of the resin, This is because the transparency of visible light is reduced due to coloring.

Further, in the case of a wavelength conversion type light emitting element which has been developed in recent years, the element emits light of a short wavelength and the light is visible by using a wavelength conversion material, specifically, a fluorescent material or the like. Convert to light wavelength. In such an optical semiconductor device, the wavelength conversion material may be dispersed in the resin,
In that case, the sealing resin needs to transmit a light beam having a short wavelength. In order to improve the transmittance of short-wavelength light, it has been conventionally used to use a compound that does not contain an aromatic structure in the molecule, and the aromatic structure, in addition to having ultraviolet absorption by the ring, particularly hydroxyl group and Having a substituent of an unsaturated group,
The extended aromatic ring of the conjugated system has a characteristic of absorbing light in the near-ultraviolet region to the visible light region, which is a cause of reducing the transmittance of short-wavelength light.

In recent years, in order to reduce the size of communication information equipment, improve the integration density, and simplify the manufacturing process, the demand for surface mounting is rapidly increasing in the semiconductor industry. This is no exception in the field of optoelectronics, and in the case of resin compositions for optical semiconductor encapsulation, even when mounting methods such as IR reflow in surface mounting are applied, package cracks due to thermal shock and between the element / lead frame and resin It is a top priority to achieve good solder resistance and transparency without peeling. As a method for improving heat resistance to obtain good solder resistance, it is common to introduce a polyfunctional compound or a compound having a rigid structure as a copolymerization component. Japanese Patent Laid-Open No. 11-24092
Japanese Patent Publication No. 3 discloses a technique in which an unsaturated polyester resin having an alicyclic skeleton and diallyl phthalate are used in combination. The cured product of this composition can have both extremely high heat resistance and visible light transmittance, but its resistance to ultraviolet light deterioration was not sufficiently improved due to the aromatic ring of diallyl phthalate. Thus, with respect to solder resistance and light transmittance, some techniques have been successful, but in addition to this, no one having good resistance to ultraviolet ray deterioration has yet been found.

[0005]

DISCLOSURE OF THE INVENTION The present invention provides an unsaturated polyester resin composition for encapsulating an optical semiconductor, which is excellent in transparency of low-wavelength light, ultraviolet ray deterioration resistance, and solder resistance, and a cured product thereof. Another object is to provide a stopped optical semiconductor device.

[0006]

DISCLOSURE OF THE INVENTION In view of such a situation, the inventors of the present invention have made earnest studies, and as a result, use an unsaturated polyester resin having a specific structure, which has a softening point and a light transmittance in a specific range. As a result, they have found that they simultaneously exhibit transparency and solder resistance and are applicable to transfer molding of a solid molding material which is usually carried out as a resin for semiconductor encapsulation, and have completed the present invention.

That is, according to the present invention, at least one or more unsaturated acid component (a) selected from maleic acid, fumaric acid and their anhydrides, and at least an aliphatic or alicyclic dihydric alcohol. 100 parts by weight of an unsaturated polyester resin (A) obtained by polymerizing one or more diol components (b), and an organic peroxide (B) 0.1 to
An unsaturated polyester resin composition containing 10 parts by weight, wherein the unsaturated polyester resin (A) contains 1 mol or more of an α, β-ethylenically unsaturated group derived from the component (a) per 1 kg of weight, In the region of 380 to 400 nm, it has a light transmittance of 90% or more at an optical path length of 1 mm, 55
An unsaturated polyester resin composition for encapsulating an optical semiconductor, which has a softening point of ℃ or more and less than 120 ° C., and a blue light emitting element, a white light emitting element, or a light receiving element for a blue laser encapsulated with a cured product thereof. It is an optical semiconductor device.

The unsaturated polyester resin (A) is preferably polymerized by containing an acid component (c) selected from an aliphatic or alicyclic saturated dibasic acid and / or an anhydride thereof. Further, the organic peroxide (B) is preferably a peroxyketal. The unsaturated polyester resin composition has a minimum melt viscosity at the molding temperature of 1
It is preferably poise or more and less than 300 poise,
In addition, when the cured product of the resin composition is 40 at a wavelength of 365 nm.
After irradiation with a high-pressure mercury lamp having an illuminance of mW / cm ² for 2 hours, it is preferable to have a light transmittance of 80% or more at an optical path length of 1 mm in a wavelength region of 380 to 400 nm.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The unsaturated polyester resin (A) used in the present invention is at least one unsaturated acid component (a) selected from maleic acid, fumaric acid and their anhydrides, an aliphatic or a fatty acid. At least one or more diol components (b) selected from cyclic dihydric alcohols, and, if necessary, acid components (c) selected from aliphatic or alicyclic saturated dibasic acids and their anhydrides. It is an unsaturated polyester resin obtained by polymerizing.

The unsaturated acid component (a) used in the present invention is one or more selected from maleic acid, fumaric acid, and their anhydrides, and it is no problem to mix and use two or more kinds. The diol component (b) used in the present invention is an aliphatic or alicyclic dihydric alcohol, and specific examples include ethylene glycol, propylene glycol,
Aliphatic glycols such as diethylene glycol, 1,2-butanediol, pentanediol, neopentyl glycol, hydrogenated bisphenol A, alkylene oxide adducts of hydrogenated bisphenol A, and alicyclic diols such as 1,4-cyclohexanedimethanol. And one kind may be used, or two or more kinds may be mixed and used.

The saturated acid component (c) used in the present invention may not necessarily be contained, but may be used together for the purpose of adjusting the softening point and the concentration of unsaturated groups. Component (c) is selected from aliphatic or alicyclic saturated dibasic acids and their anhydrides, and does not include those corresponding to component (a). Specifically, aliphatic dibasic acids such as malonic acid, succinic acid, adipic acid, sebacic acid, hexahydrophthalic acid, 1,4-cyclohexanedicarboxylic acid, methylhexahydrophthalic acid, tetrahydrophthalic acid, nadic acid, etc. The alicyclic dibasic acids and their anhydrides may be used, and one kind may be used or two or more kinds may be used in combination.

A known method may be used to polymerize the unsaturated polyester resin (A) used in the present invention. For example, for convenience, dibasic acid anhydrides are used as the components (a) and (c). A polyester can be obtained by heat polymerization using a diol as the component (b). Further, for the purpose of reducing the colorability and making the polymerization degree of the obtained polyester uniform, the acid components of the components (a) and (c) are converted into an ester with a low molecular weight alcohol or an esterifying agent, and It can also be obtained by reacting with the diol which is the component (b) and removing the removable component. In addition, JP-A-1
It is also possible to synthesize by the method disclosed in JP-A 1-214439 and JP-A 11-240924.

The unsaturated polyester resin (A) thus obtained contains the α, β-ethylenically unsaturated group derived from the component (a) in an amount of 1 kg of the unsaturated polyester resin.
1 mol or more per 1 mol, and in the wavelength range of 380 to 400 nm, it is essential that the optical path length is 1 mm, the light transmittance is 90% or more, and the softening point is 55 ° C. or more and less than 120 ° C. When the α, β-ethylenically unsaturated group derived from the component (a) is contained in the concentration range, the cured product of the unsaturated polyester resin composition can exhibit high heat resistance. When it is less than 1 mol per 1 kg of the resin, specifically, when a large amount of the dibasic acid of the component (c) is contained,
When a compound having a large molecular weight is used as the components (a) and (b), a sufficient level of heat resistance for solder reflow cannot be obtained due to a decrease in the crosslink density of the resin.

Unsaturated polyester resin (A) having a wavelength of 3
The light transmittance in the region of 80 to 400 nm is 1
When it is less than 90% in mm, specifically, it may be colored due to the presence of impurities at the time of polymerization. In such a case, even when it is used for encapsulating an optical semiconductor, it absorbs ultraviolet rays, The required light rays are blocked, and the optical semiconductor device cannot obtain sufficient light emitting performance. The light transmittance is measured by melting an unsaturated polyester resin, pouring it between glass parallel plates with a spacer such as a 1 mm thick silicone rubber sandwiched between them, and cooling the surface of the resin plate to make it smooth,
It is measured at a thickness of 1 mm. A Shimadzu spectrophotometer UV-3100 (integrating sphere device installed type) may be used as the measuring device.

If the softening point is less than 55 ° C., it is difficult to obtain a solid molding material at room temperature, and the handling property is poor, which is not preferable. If the softening point is higher than 120 ° C., high temperature is required when melt-mixing the component (A) with other additives, and the decomposition of the organic peroxide of the component (B) may proceed excessively. Not preferable. The softening point can be measured by a conventionally known method. Specifically, it can be measured by spraying a resin powder on a metal plate having a temperature gradient, known by the name of Kofler hot bench, and measuring the temperature at the point where the resin melts and sticks to the metal plate.

The organic peroxide (B) used in the present invention is
The type of the component (A) is not limited as long as it can accelerate the curing reaction, but in the production of the resin composition of the present invention, heat kneading is performed at a temperature equal to or higher than the softening point of the component (A). In this case, it is preferable to use a high temperature curable peroxide in order to prevent the reaction from being excessively promoted during kneading and gelation. As the organic peroxide, dicumyl peroxide, 1,1-bis (t-butylperoxy) -3,3,3
5-Trimethylcyclohexane, benzoyl peroxide, t-butyl peroxyisopropyl monocarbonate and the like can be mentioned, and these may be used alone or in combination of two or more. Of these, the use of peroxyketals is particularly preferable because the cured product is less colored. Examples of peroxyketals include:
1,1-bis (t-butylperoxy) -3,3,5-
Examples thereof include trimethylcyclohexane, 1,1-bis (t-hexylperoxy) -3,3,5-trimethylcyclohexane and 1,1-bis (t-hexylperoxy) cyclohexane.

If necessary, the unsaturated polyester resin composition for encapsulating an optical semiconductor of the present invention may be combined with additives and auxiliary materials known to those skilled in the art such as a release agent, a lubricant, an antioxidant and the like. It doesn't matter. Further, the copolymerizable monomer may be used in combination as long as it does not impair its properties, particularly the handling property at room temperature and the resistance to deterioration by ultraviolet light.

In the unsaturated polyester resin composition for optical semiconductor encapsulation of the present invention, the amount of the component (B) added is
0.1 to 10 parts by weight is preferable with respect to 100 parts by weight of the component (A). If it exceeds this range, the heat generated during curing becomes excessive, and the resin tends to discolor. If it is less than this range, sufficient curability cannot be obtained in a short time.

The method for producing the unsaturated polyester resin composition for encapsulating an optical semiconductor of the present invention comprises mixing the components (A) and (B) and other components, and kneading, heating a roll,
The method of melting, heating, and kneading with equipment such as a single-screw or twin-screw extruder is generally used.

The unsaturated polyester resin composition for encapsulating an optical semiconductor of the present invention has a minimum melt viscosity at the molding temperature of 1
It is preferably poise or more and less than 300 poise.
Such a viscosity can be easily measured by using a device such as a Koka type flow tester. Viscosity 1
When it is less than poise, the fluidity becomes too large at the time of molding, a large amount of burr is generated, and the efficiency of the molding operation may be lowered. When it exceeds 300 poises, the fluidity becomes remarkably low, which may cause deterioration of the filling property and voids.

In order for the unsaturated polyester resin composition for encapsulating an optical semiconductor of the present invention to exhibit more preferable characteristics, the cured product has an illuminance of 40 measured at a wavelength of 365 nm.
After irradiation with a high pressure mercury lamp of mW / cm ² for 2 hours, a wavelength of 38
The light transmittance in the range of 0 to 400 nm is determined by the optical path length of 1 m.
It is preferable that m is 80% or more. Unsaturated polyester resin composition for optical semiconductor encapsulation having such characteristics, especially when encapsulating an optical semiconductor device that receives and emits light of a low wavelength, little deterioration due to low wavelength light emitted by the semiconductor element, Since the optical semiconductor device can maintain the transmissivity for a long time, it is possible to suppress the occurrence of reliability problems such as a decrease in output.

Light irradiation with a high-pressure mercury lamp can be easily carried out by using a commercially available ultraviolet irradiation device and a high-pressure mercury lamp. Specifically, multi-light ML-251A type ultraviolet light manufactured by Ushio Inc. Using an irradiation device and a USH-250BY type high-pressure mercury lamp, the intensity of ultraviolet light of 365 nm on the sample surface was 40 mW / c.
It can be performed by adjusting with an ultraviolet illuminance measuring device so as to be m ² .

The light transmittance can be measured by the same device as that used for measuring the resin alone. The test piece is prepared by making a cured product into a plate shape of 10 × 30 × 1 mm and smoothing the surface. When the light transmittance of this test piece is lower than 80%,
Even with the unsaturated polyester resin composition of the present invention, the deterioration rate of the luminance of the light emitting element may increase due to the deterioration of the resin.

The cured product of the unsaturated polyester resin composition of the present invention is suitable for encapsulating an optical semiconductor device, but is particularly suitable for a blue light emitting element, a white light emitting element, or a light receiving element for a blue laser. And the wavelength conversion type blue,
When an element type that emits short-wavelength light such as a white light emitting element is sealed, it is possible to provide an optical semiconductor device having extremely excellent transparency, resistance to ultraviolet ray deterioration, and resistance to soldering.

The encapsulation using the unsaturated polyester resin composition for encapsulating an optical semiconductor of the present invention can be carried out by a general method, for example, by a transfer molding method or the like.
At a molding temperature of 0 to 200 ° C., the optical semiconductor element is sealed,
An optical semiconductor device encapsulated with a cured product of an unsaturated polyester resin composition for optical semiconductor encapsulation can be obtained.

[0026]

The present invention will now be described in more detail with reference to the following examples, which should not be construed as limiting the invention thereto.

[Synthesis of Unsaturated Polyester Resin] Components (a) to (c) and components corresponding to other acids and other diols are mixed in the mixing ratio shown in Table 1 to prepare a sub-polymerization catalyst. Phosphoric acid was added and the mixture was heated and reacted at 160 to 240 ° C. When the reaction proceeded and a desired softening point was obtained, the reaction product was taken out and cooled to obtain unsaturated polyester resin samples (A) to (I), respectively. The reaction of the unsaturated polyester resin (E) is described in JP-A-1.
The method described in the synthesis of unsaturated polyester resin (A-2) in JP-A 1-240924 was followed. Further, in the reaction of the unsaturated polyester resin (G), a raw material having a low purity was used, and therefore the composition and the reaction method are the same as those of the unsaturated polyester resin (A), but the obtained resin is slightly yellow. It was tasty. The characteristics of the obtained unsaturated polyester resin have a softening point of 380 to 400 n.
It was evaluated by the m-ray transmittance and the double bond content.

[0028]

[Table 1] In Table 1, Note 1: Bisphenol A having an average molecular weight of 236
Ethylene oxide adduct, Note 2: Measured using the Kofler hot bench method, Note 3: Measured using a cast resin plate having a thickness of 1 mm, Note 4: Measured by the iodine method.

[Examples 1 to 5 and Comparative Examples 1 to 3] Components (A) to (C) and components corresponding to the polymerizable monomer were added.
Mix at the blending ratio shown in Table 2, use a two-roll,
The mixture was kneaded at 70 to 100 ° C. for 5 minutes, and the obtained kneaded material sheet was cooled and then pulverized to obtain a resin composition. Evaluation was performed using the obtained resin composition. The evaluation method is as follows, and the results are summarized in Table 2.

[Measurement of Light Transmittance] A tablet of the resin composition obtained above was used at a mold temperature of 160 ° C. and an injection pressure of 6.
Transfer molding was performed under the conditions of 86 MPa and a curing time of 90 seconds to obtain a molded product of 30 × 10 × 1 mm. Using a spectrophotometer (manufactured by Shimadzu Corp., self-recording spectrophotometer UV-3100) equipped with an integrating sphere, this molded product was measured at wavelengths of 380 to 4
The average light transmittance of 00 nm and a thickness of 1 mm was measured. [Evaluation of resistance to ultraviolet ray deterioration] Multi-light ML-251 manufactured by USHIO INC. Was added to the above-mentioned 1 mm thick test piece for transparency evaluation.
Using an A-type ultraviolet irradiation device and a USH-250BY high-pressure mercury lamp, a light beam adjusted with an ultraviolet illuminance measuring device so that the intensity of the 365 nm ultraviolet light at the sample position is 40 mW / cm ² is used for 2 hours. Irradiated. After irradiation, using a spectrophotometer (Shimadzu Corporation self-recording spectrophotometer UV-3100) equipped with an integrating sphere, a wavelength of 380 to 40
The average light transmittance of 0 nm was measured to evaluate the resistance to ultraviolet ray deterioration. [Measurement of Melt Viscosity] A tablet (φ10 mm, 1.4 g) of the resin composition obtained above was loaded with a Shimadzu high-performance flow tester CFT-100D at a load of 30 k.
The minimum melt viscosity was measured under the conditions of g, nozzle 0.5 mmφ × 10 mL, and temperature 160 ° C. [Measurement of glass transition temperature] A tablet of the resin composition obtained above was used at a mold temperature of 160 ° C and an injection pressure of 6.86M.
A test piece was formed by transfer molding under the conditions of Pa and a curing time of 90 seconds, and the test piece was post-cured in a hot air oven at a temperature of 150 ° C. for 2 hours, and then a thermal expansion meter (TMA120 manufactured by Seiko Instruments Inc.) was used. The temperature was raised at a heating rate of 5 ° C./min, and the temperature at which the elongation of the test piece suddenly changed was measured as the glass transition point. [Evaluation of Solder Resistance] Tablets of the resin composition obtained above are cleaned with a melanin resin cleaning material for surface mounting package (12-pin SOP, 4 ×
5 mm, thickness 1.2 mm, chip size 1.5 mm ×
2.0 mm, lead frame made of 42 alloy) Using a mold, transfer molding was performed under the conditions of a mold temperature of 160 ° C., an injection pressure of 6.86 MPa, and a curing time of 90 seconds, and a temperature of 15
Cured in a hot air oven at 0 ° C. for 2 hours. The obtained optical semiconductor package was left for 168 hours in an environment of a temperature of 85 ° C. and a relative humidity of 60%, and then subjected to an IR reflow treatment at 240 ° C. The treated package was observed with a microscope and an ultrasonic flaw detector to confirm the presence of cracks and peeling between the chip and the resin. If there was cracking or peeling, it was determined to be defective. [Evaluation of resistance to energization deterioration] A tablet of the resin composition obtained above is a chip type LED package (2.0 × 1.
0 mm, thickness 1.6 mm, chip has main emission peak at 415 nm, blue light emitting device of InGaN semiconductor) Using a mold, mold temperature 160 ° C., injection pressure 6.86 MP
a, transfer molding was performed under the conditions of a curing time of 90 seconds, and cured in a hot air oven at a temperature of 150 ° C. for 2 hours. Apply 10 mA to the obtained optical semiconductor package while applying a current of 60 mA.
The sample was allowed to stand for 00 hours and the relative emission intensity after the treatment was evaluated as good when it was maintained at 60% or more as compared with that before the treatment, and as poor when it was less than 60%.

[0031]

[Table 2] In Table 2, Note 1: Daiso's polymerizable monomer (isophthalic acid diallyl ester), Note 2: PPG Japan Co., Ltd. polymerizable monomer (bisethylene glycol diallyl carbonate), Note 3: Kyoeisha Chemical's polymerization Monomer (methacrylic acid diester of bisphenol A epoxy), Note 4: NOF's organic peroxide (dicumyl peroxide), Note 5: NOF's organic peroxide (1,1)
-Bis (t-butylperoxy) -3,3,5-trimethylcyclohexane), Note 6: Organic peroxide (1,1-bis (t-hexylperoxy) -3,3, manufactured by NOF CORPORATION
5-trimethylcyclohexane), Note 7: In heating and kneading, curing proceeded excessively, and materialization could not be evaluated.

As is clear from the results in the table, the unsaturated polyester resin composition for encapsulating an optical semiconductor of the present invention has transparency,
It can be seen that the ultraviolet resistance and the heat resistance are excellent, and the package using the same is excellent in the solder resistance and the resistance to electrical deterioration.

[0033]

Industrial Applicability The unsaturated polyester resin composition for optical semiconductor encapsulation of the present invention is excellent in transparency, ultraviolet ray deterioration resistance and heat resistance, and is excellent in solder resistance and resistance to energization deterioration. Can be provided.

Claims (6)

[Claims] 1. At least one unsaturated acid component (a) selected from maleic acid, fumaric acid and their anhydrides, and at least one selected from aliphatic or alicyclic dihydric alcohols. An unsaturated polyester resin composition comprising 100 parts by weight of an unsaturated polyester resin (A) obtained by polymerizing a diol component (b) and 0.1 to 10 parts by weight of an organic peroxide (B), The saturated polyester resin (A) contains 1 mol or more of the α, β-ethylenically unsaturated group derived from the component (a) per 1 kg of weight,
Optical path length of 1 mm in the wavelength range of 380 to 400 nm
At 90% or more, and an unsaturated polyester resin composition for optical semiconductor encapsulation having a softening point of 55 ° C or higher and lower than 120 ° C. 2. The light according to claim 1, wherein the unsaturated polyester resin (A) is polymerized to contain an acid component (c) selected from an aliphatic or alicyclic saturated dibasic acid and an anhydride thereof. Unsaturated polyester resin composition for semiconductor encapsulation. 3. The unsaturated polyester resin composition for optical semiconductor encapsulation according to claim 1, wherein the organic peroxide is a peroxyketal. 4. The unsaturated polyester resin composition for optical semiconductor encapsulation according to claim 1, 2 or 3, which has a minimum melt viscosity at a molding temperature of 1 poise or more and less than 300 poise. 5. The cured product of the resin composition has a wave of 365 nm.
40mW / cm long ²High-pressure mercury lamp with illuminance of 2 hours
Later, in the wavelength range of 380 to 400 nm, the optical path length
The light transmittance of 80% or more at 1 mm is obtained.
The unsaturated polyester resin for encapsulating an optical semiconductor according to any one of
Fat composition. 6. A blue light emitting device, a white light emitting device, or a light receiving device for a blue laser, which is encapsulated with a cured product of the unsaturated polyester resin composition for encapsulating an optical semiconductor according to claim 1. An optical semiconductor device comprising an element.