JP2007194268A - Optical semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a highly reliable optical semiconductor device obtained by fixing a light emitting element by using die bonding resin paste which has high heat conductivity, is superior in adhesive property, and has high heat resistance. <P>SOLUTION: In the optical semiconductor device, a light emitting element chip is fixed on an upper face of a substrate where an electrode is formed through an adhesive layer, and the light emitting chip is sealed. Adhesion strength with a frame is 1 kgf/mm<SP>2</SP>or above after the adhesive layer is processed with a condition of 85°C×85%RH×72 hours and is reflow-processed at 260°C. Thermal conductivity is 20 W/mK or above and electrical resistivity is 7×10<SP>-6</SP>Ω cm or below. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an optical semiconductor device in which an LED chip is fixed using a die bonding paste excellent in high thermal conductivity, high heat resistance, and high adhesion.

  A light-emitting element (hereinafter also referred to as an LED chip) can emit light of a small color efficiently and vividly, and since it is a semiconductor element, it does not run out of spheres. In addition, it has excellent drive characteristics and is strong against vibration and repeated ON / OFF lighting, so it is used as various indicators and various light sources.

  An LED chip is used by being fixed to a substrate with a resin paste for die bonding (hereinafter also referred to as a mount member). There is a need for an optical semiconductor device capable of emitting light with high brightness. Furthermore, since LED chips that can emit light with high brightness (hereinafter also referred to as power LEDs) generate a large amount of heat from the chips, the die bonding resin that fixes them has high heat resistance in addition to adhesiveness. In addition, properties such as high thermal conductivity and high electrical conductivity are strongly demanded.

For these corresponding applications, improvement studies have been made more than ever, but diode die bonding pastes with improved adhesion and heat resistance are known (for example, see Patent Document 1), which is sufficiently satisfactory. At present, the reliability is not obtained.
JP 2004-266134 A

  Accordingly, the present invention provides a highly reliable optical semiconductor device obtained by fixing a light emitting element using a resin paste for die bonding that has high thermal conductivity, excellent adhesion, and high heat resistance. It is intended to do.

As a result of intensive research aimed at developing an optical semiconductor device capable of emitting light with higher reliability and longer light intensity, the present inventors have found that the adhesive strength after curing with a chip is 85 ° C. × 85 % RH × 72 hours of treatment, and after 260 ° C. reflow treatment, the adhesion strength with the frame is 1 kgf / mm ² or more, the thermal conductivity is 20 W / m · K or more, and the electrical resistivity is 7 ×. It has been found that the object can be achieved by using a die bonding paste of 10 ⁻⁶ Ω · cm or less.

That is, the optical semiconductor device of the present invention is an optical semiconductor device in which a light emitting element chip is fixed to an upper surface of a substrate on which an electrode is formed via an adhesive layer, and the light emitting element chip is sealed. Is processed under conditions of 85 ° C. × 85% RH × 72 hours, and after reflow treatment at 260 ° C., the adhesive strength with the frame is 1 kgf / mm ² or more, and the thermal conductivity is 20 W / m · K or more. In addition, the electrical resistivity is 7 × 10 ⁻⁶ Ω · cm or less.

（式中、ｎは０〜１の整数であり、Ｘは同一又は異なって、ＳＯ、ＳＯ_２、ＣＨ_２、Ｃ（ＣＨ_３）_２、Ｃ（ＣＦ_３）_２、Ｏ、ＣＯ及びＣＯＯから選ばれる官能基であり、Ｒ^１〜Ｒ^８は同一又は異なって、水素原子、置換基を有してもよいアルキル基又は置換基を有してもよいアリル基であり、少なくとも１つは置換基を有してもよいアリル基である。）、（Ｃ）常温で固形のフェノール性硬化剤及び（Ｄ）比表面積（ＳＡ）が１．３ｍ^２／ｇ以下、かつタップ密度（ＴＤ）が４．０〜７．０ｇ／ｃｍ^３である銀粉、を含有するダイボンディング用樹脂ペーストにより接着剤層を形成することにより達成されるものである。 In order to obtain such an adhesive layer, (A) an epoxy resin that is solid at room temperature, (B) an allylated epoxy compound represented by the following general formula (I)

(In the formula, n is an integer of 0 to 1, X is the same or different and is selected from SO, SO ₂ , CH ₂ , C (CH ₃ ) ₂ , C (CF ₃ ) ₂ , O, CO and COO) Wherein R ^{1 to} R ⁸ are the same or different and are a hydrogen atom, an alkyl group which may have a substituent, or an allyl group which may have a substituent, at least one of which is a substituent. And (C) a solid phenolic curing agent at room temperature and (D) a specific surface area (SA) of 1.3 m ² / g or less and a tap density (TD) of 4. This is achieved by forming an adhesive layer with a resin paste for die bonding containing 0.0 to 7.0 g / cm ³ of silver powder.

  According to the present invention, even after the light emitting element chip is fixed to the substrate, the light emitting element chip can emit light with high brightness for a long period of time by reducing the influence of the adhesive layer that inhibits light emission of the chip. A highly reliable optical semiconductor device can be provided.

  The method for manufacturing the optical semiconductor device of the present invention will be described below.

  In the present invention, the light emitting element chip is not particularly limited as long as it is a light emitting element used in a conventionally known optical semiconductor device. As such a light emitting element, for example, a semiconductor material is laminated on a substrate provided with a buffer layer of GaN, AlN or the like, if necessary, by various methods such as MOCVD, HDVPE, and liquid phase growth. Things.

  Various materials can be used as the substrate in this case, and examples thereof include sapphire, spinel, SiC, Si, ZnO, and GaN single crystals. Of these, it is preferable to use sapphire from the viewpoint that solid GaN can be easily formed and has high industrial utility value.

  Examples of laminated semiconductor materials include GaAs, GaP, GaAlAs, GaAsP, AlGaInP, GaN, InN, AlN, InGaN, InGaAIN, and SiC. Among these, a nitride compound semiconductor (Inx Gay Alz N) is preferable from the viewpoint of high luminance and high output with a blue light emitter and a large calorific value. Such a material may contain an activator or the like.

  Examples of the structure of the light-emitting element include a homojunction having a MIS junction, a pn junction, and a PIN junction, a heterojunction, and a double heterostructure. Moreover, it can also be set as a single or multi-mass well structure. The light emitting element may or may not be provided with a passivation layer.

  An electrode can be formed on such a light emitting element by a conventionally known method. The electrode on the light-emitting element can be electrically connected to the lead terminal or the like by various methods, and the electrical connection member preferably has good ohmic mechanical sustainability with the electrode of the light-emitting element, for example, gold, silver, copper Bonding wires using platinum, aluminum, alloys thereof, and the like can be given. Alternatively, a conductive adhesive or the like in which a conductive filler such as silver or carbon is filled with a resin can be used. Among these, it is preferable to use an aluminum wire or a gold wire from the viewpoint of good workability.

  A light-emitting element can be obtained as described above. In the optical semiconductor device of the present invention, it is preferable to use any light-emitting element as long as the light intensity in the vertical direction is 1 cd or more. Here, the case where a light emitting element having a luminous intensity in the vertical direction of 2 cd or more is used from the viewpoint that the effect of the present invention can be effectively exerted, and the case where a light emitting element of 3 cd or more is used more effectively. It is preferable at the point which can be exhibited effectively.

  The light emitting output of the light emitting element is not particularly limited, and any light emitting output can be used. However, when a light emitting element of 1 mW or more is used at 20 mA, the effect of the present invention can be effectively exhibited. The effect of the present invention can be more effectively exhibited when a light emitting element of 4 mW or more is used, and the effect of the present invention can be more effectively exhibited when a light emitting element of 5 mW or more is used at 20 mA. This is preferable.

  Various light emission wavelengths from the ultraviolet region to the infrared region can be used for the light emitting element, but the effect of the present invention is particularly effective when the main light emission peak wavelength is 550 nm or less. . One type of light emitting element may be used for monochromatic light emission, or a plurality of light emitting elements may be used for single color or multicolor light emission.

  The lead terminal used in the optical semiconductor device of the present invention preferably has good adhesion to an electrical connecting member such as a bonding wire, electrical conductivity, etc., and the electrical resistance of the lead terminal is 300 μΩ-cm or less. Preferably, it is 3 μΩ-cm or less. Examples of these lead terminal materials include iron, copper, iron-containing copper, tin-containing copper, and those plated with silver, nickel, or the like. The glossiness of these lead terminals may be adjusted as appropriate in order to obtain a good light spread.

Next, the bonding resin paste of the present invention has the following predetermined physical properties, that is, after curing, is treated under the conditions of 85 ° C. × 85% RH × 72 hours, and further has an adhesive strength of 1 kgf with the chip after 260 ° C. reflow treatment. It is essential to ensure physical properties that are not less than / mm ² , thermal conductivity is not less than 20 W / m · K, and electrical resistivity is not more than 7 × 10 ⁻⁶ Ω · m.

If the adhesive strength is 85 ° C. × 85% RH × 72 hours, and if it is 1 kgf / mm ² or less after 260 ° C. reflow treatment, chip peeling problems are likely to occur. Sufficient reliability as a device cannot be obtained.

Further, when the thermal conductivity is 20 W / m · K or less, the temperature rise of the optical semiconductor device becomes a problem, and when the electrical resistivity is 7 × 10 ⁻⁶ Ω · cm or more, sufficient luminous efficiency is obtained. I can't.

  The optical semiconductor device of the present invention can be manufactured by coating a light emitting element with various resins. In this case, the coating directly seals the light emitting element fixed on the substrate as described above. It includes not only the case but also the case of indirectly covering. Specifically, the light-emitting element may be directly sealed with the adhesive composition used in the present invention by various conventionally used methods, or conventionally used epoxy resin, silicone resin, acrylic resin, urea resin, The light emitting element may be sealed with a sealing resin such as an imide resin or glass.

  Further, after sealing the light emitting element with the adhesive composition of the present invention, it may be molded with a conventionally used epoxy resin, silicone resin, acrylic resin, urea resin, imide resin or the like. Various effects such as the re-lens effect can be provided by the difference in refractive index and specific gravity by the above method.

  Various methods can be applied as a sealing method. For example, a liquid composition may be injected into a cup, cavity, package recess, or the like in which a light emitting element is arranged at the bottom by a dispenser or other method and cured by heating, or a solid or highly viscous liquid composition The material may be heated and flowed, and similarly injected into a package recess or the like and further heated to be cured.

  The package in this case can be made using various materials, such as polycarbonate resin, polyphenylene sulfide resin, epoxy resin, acrylic resin, silicone resin, ABS resin, polybutylene terephthalate resin, polyphthalamide resin, and the like. be able to.

  As a more specific method of sealing, a method of injecting a composition in advance into a mold mold, dipping a lead frame or the like on which a light emitting element is fixed, and curing it can be applied. The sealing layer made of the composition may be molded and cured by injection with a dispenser, transfer molding, injection molding or the like in a mold in which the element is inserted.

  Alternatively, the composition in a liquid or fluid state may be dropped or coated into a light-emitting element and cured, or curable resin may be applied to the light-emitting element through stencil printing, screen printing, or a mask. Can be molded and cured. In addition, you may carry out by the method of fixing on a light emitting element the composition partially hardened or hardened beforehand in plate shape or a lens shape.

  The shape of the covering portion is not particularly limited and can take various shapes. These shapes may be formed by molding and curing the sealing composition, or may be formed by post-processing after the sealing composition is cured.

  The optical semiconductor device of the present invention can be of various types, for example, any type such as a lamp type, an SMD type, and a chip type. Various types of SMD type and chip type package substrates are used, and examples thereof include epoxy resin, BT resin, and ceramic.

  The optical semiconductor device of the present invention can be used for various known applications. Specifically, a backlight, illumination, a sensor light source, a vehicle instrument light source, a signal lamp, an indicator lamp, a display device, a light source of a planar light emitter, a display, a decoration, various lights, and the like can be given.

  The die bonding paste of the present invention comprises (A) an epoxy resin that is solid at room temperature, (B) an allylated epoxy compound having a specific structure, (C) a phenol resin curing agent that is solid at room temperature, and (D) a specific property. It is an electroconductive paste containing the silver powder which has.

  The die bonding paste of the present invention improves the thermal conductivity of the die bonding paste by blending an epoxy resin having a specific structure as described above and a silver powder having a specific property, and generates heat generated from a semiconductor element. Can be efficiently diffused to the outside of the package through the die bonding paste, and the temperature rise of the semiconductor element itself can be suppressed, and in particular, the adhesion to the gold surface can be improved.

[(A) component]
In the die bonding paste of the present invention, any epoxy resin can be used as long as the epoxy resin as component (A) has two or more epoxy groups in one molecule and is solid at room temperature (23 ° C.). be able to. Examples thereof include bisphenol A type epoxy resin, bisphenol F type epoxy resin, cresol novolac type epoxy resin, glycidyl ester type epoxy resin, special polyfunctional type epoxy resin, and alicyclic epoxy resin. However, the allylated epoxy resin which is the component (B) described below is not included.

  These epoxy resins that are solid at normal temperature (23 ° C.) may be used singly or in combination of two or more. Furthermore, the epoxy resin that is liquid at normal temperature (23 ° C.) can be used in combination by replacing all or part of the solid epoxy resin as appropriate.

  In the present invention, together with the epoxy resin of the component (A), other resins can be used in combination within the range that does not impair the effects of the present invention for the purpose of stress relaxation and adhesion. Examples of other resins include polyester resins, polybutadiene resins, silicone resins, polyurethane resins, and xylene resins.

（式中、ｎは０〜１の整数であり、Ｘは同一又は異なって、ＳＯ、ＳＯ_２、ＣＨ_２、Ｃ（ＣＨ_３）_２、Ｃ（ＣＦ_３）_２、Ｏ、ＣＯ及びＣＯＯから選ばれる官能基であり、Ｒ^１〜Ｒ^８は同一又は異なって、水素原子、置換基を有してもよいアルキル基又は置換基を有してもよいアリル基であり、少なくとも１つは置換基を有してもよいアリル基である。）である。 [Component (B)]
The allylated epoxy resin which is the component (B) used in the present invention is a compound represented by the following general formula (I)

(In the formula, n is an integer of 0 to 1, X is the same or different and is selected from SO, SO ₂ , CH ₂ , C (CH ₃ ) ₂ , C (CF ₃ ) ₂ , O, CO and COO) Wherein R ^{1 to} R ⁸ are the same or different and are a hydrogen atom, an alkyl group which may have a substituent, or an allyl group which may have a substituent, at least one of which is a substituent. It is an allyl group which may have.

  Moreover, it is preferable that content of the allylation epoxy resin of (B) component is a ratio of 0.5-3.0 with respect to 1.0 epoxy equivalent of the epoxy resin of (A) component. When the content of the (B) component allylated epoxy resin is within this range, good adhesion of the die bonding paste can be obtained.

[Component (C)]
In the die bonding paste of the present invention, the curing agent used as the component (C) is a phenol resin curing agent that is solid at room temperature (23 ° C.), and preferably has a number average molecular weight of 500 or more. Although there is no restriction | limiting in particular about the upper limit of a number average molecular weight, Usually about 10,000 can be used preferably.

  Examples of such a curing agent include novolac type phenol resins, novolac type cresol resins, vinylphenol polymers (poly-p-vinylphenol and the like), bisphenol resins, phenol biphenylene resins, and the like. These may be used singly or in combination of two or more.

  The amount of the phenol resin curing agent used as the component (C) is such that the hydroxyl group equivalent is 0.5 per epoxy equivalent of the epoxy resin of the component (A) and the allylated epoxy resin of the component (B). An amount of ~ 1.5 is preferred.

[(D) component]
The silver powder of component (D) in the die bonding paste of the present invention has a specific surface area (SA) of 1.3 m ³ / g or less and a tap density (TD) of 4.0 to 7.0 g / cm ³ . It is the powder which has.

Here, if the specific surface area (SA) is 1.3 m ² / g or less, the filling rate of the silver powder becomes good, and the improvement of the thermal conductivity of the die bonding paste can be expected, and the die bonding paste is suitable. It has viscosity and is good in terms of spreadability. This is no particular limitation on the lower limit of the specific surface area, since the preferably used to usually 0.2 m ² / g approximately, the specific surface area is preferably in the range of 0.2~0.7m ² / g.

On the other hand, if the tap density is 4.0 m ² / g or more, the thermal conductivity of the cured product of the die bonding paste is good, and if it is 7.0 m ² / g or less, the thixotropy of the die bonding paste is high. It becomes good, and the occurrence of stringing during the dispensing of the paste is suppressed.

Therefore, if the tap density of the silver powder is 4.0 to 7.0 g / cm ³ , both characteristics are well balanced and sufficient effects can be obtained. The one close to 7.0 g / cm ³ is preferable because the characteristics as an optical semiconductor are further improved.

  There is no restriction | limiting in particular in the particle size of the said silver powder, Silver powder of various particle sizes can be used if it satisfies the above-mentioned specific surface area and tap density. In order to make the specific surface area and tap density of the said silver powder into the above ranges, it can carry out by controlling the shape of silver powder, for example. Specifically, the specific surface area and the tap density as described above can be realized by making the shape of the silver powder an intermediate shape (flat shape) between a spherical shape and a scale shape.

  It is preferable that content of the silver powder of (D) component is 90 mass% or more of the die bonding paste total mass of this invention. If content without silver powder is 90 mass% or more, the filling rate without the said silver powder will become high, and the thermal conductivity of die-bonding paste will improve. Further, from the viewpoint of the adhesive strength of the die bonding paste cured product, the content of the silver powder is preferably 99% by mass or less.

  In the die bonding paste of the present invention, a part of the silver powder of component (D) can be replaced with another conductive powder. Examples of other conductive powders include nickel powder, gold powder, and copper powder. In this case, the content of the other conductive powder is preferably 20% by mass or less in the total conductive powder.

  A silane coupling agent containing a (meth) acryl group can be further added to the die bonding paste of the present invention. The silane coupling agent preferably contains a (meth) acryl group from the viewpoint of obtaining good adhesiveness. Examples of such a silane coupling agent include 3- (meth) acryloxy. Propyltrimethoxysilane, 3- (meth) acryloxypropylmethyldimethoxysilane, 3- (meth) acryloxypropyldimethylmethoxysilane, 3- (meth) acryloxypropyltriethoxysilane, 3- (meth) acryloxypropylmethyl Examples include diethoxysilane and 3- (meth) acryloxypropyldimethylethoxysilane. One of these silane coupling agents may be used alone, or two or more thereof may be used in combination.

  Moreover, it is preferable that the said silane coupling agent is the range of 0.01-2.0 mass% of the die bonding paste total mass of this invention. Sufficient adhesion can be secured by setting it to 0.01% by mass or more, and generation of bubbles due to outgas, that is, a silane coupling agent can be suppressed by setting it to 2.0% by mass or less. Obtainable.

  In the die bonding paste of the present invention, in addition to the above-mentioned components, a curing accelerator such as imidazoles, a solvent for adjusting the viscosity of the die bonding paste, a reactive diluent having an epoxy group ring-opening polymerization property, Furthermore, adhesive strength improvers such as coupling agents and acid anhydrides, fine silica powder, antifoaming agents, and other various additives can be blended within a range that does not interfere with the function of the die bonding paste.

  Examples of the solvent include cellosolve acetate, ethyl cellosolve, butyl cellosolve, butyl cellosolve acetate, butyl carbitol acetate, propylene glycol phenyl ether, diethylene glycol dimethyl ether, diacetone alcohol and the like. These may be used singly or in combination of two or more.

  Examples of the reactive diluent include n-butyl glycidyl ether, allyl glycidyl ether, 2-ethylhexyl glycidyl ether, styrene oxide, phenyl glycidyl ether, and cresyl glycidyl ether. These may be used singly or in combination of two or more.

  The die bonding paste of the present invention comprises the above-described (A) component epoxy resin, (B) component allylated epoxy resin, (C) component phenol resin-based curing agent, (D) component silver powder, and as required. By adding a silane coupling agent, curing accelerator, solvent, reactive diluent, etc. used and mixing well, further kneading with a disperser, kneader, three roll mill, etc., then defoaming Can be easily prepared.

  The die bonding paste of the present invention thus obtained is excellent in workability, and contains the epoxy resin having a specific structure and the silver powder having a specific property, so that the thermal conductivity of the die bonding paste is improved. It is possible to efficiently dissipate the heat generated from the semiconductor element to the outside of the package through the die bonding paste, thereby suppressing the temperature rise of the semiconductor element itself, and particularly improving the adhesion to the gold surface It is possible to make it.

  The light-emitting element using the die bonding paste can be fixed by filling the die bonding paste of the present invention into a syringe, discharging it onto a substrate using a dispenser, and bonding the light-emitting element by curing. Furthermore, a resin-sealed semiconductor device can be manufactured by performing wire bonding and sealing with a resin sealing material. In addition, when hardening the die-bonding paste of this invention, it is preferable to heat for 1 to 3 hours normally at 100-250 degreeC.

  EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by these Examples.

Example 1
(A) 5 parts by mass of a cresol novolac type epoxy resin (manufactured by Nippon Kayaku Co., Ltd., EOCN4500; epoxy equivalent 200) as a solid epoxy resin at room temperature, (B) 5 parts by mass of an allylated epoxy resin (Nippon Kayaku ( RE-810NM; epoxy equivalent 220), (C) 15 parts by mass of phenol / biphenylene resin (Maywa Kasei Co., Ltd., MEH-7851; hydroxyl equivalent 200, number average molecular weight 800), (D) 690 parts by mass of silver powder I (flaky, tap density 6.4 g / cm ³ , specific surface area 0.2 m ² / g), 50 parts by mass of butyl carbitol acetate as a solvent, 1 part by mass of imidazole as a curing accelerator (Manufactured by Shikoku Kasei Kogyo Co., Ltd., 2MA-OK), 3-methacryloxypropyltrimethoxysila as a coupling agent The paste was adjusted by a conventional method using 1 part by mass. Thereafter, a light-emitting element 1 mm × 1 mm having a light emission output of 4 mW at a composition of InGaN, 20 mA, an epoxy resin for sealing (trade name: NLP-L-438, manufactured by Sanyu Rec Co., Ltd.) as a sealing material, and an optical semiconductor device Manufactured.

(Example 2)
(A) 5 parts by mass of a cresol novolac type epoxy resin (manufactured by Nippon Kayaku Co., Ltd., EOCN4500; epoxy equivalent 200) as a solid epoxy resin at room temperature, (B) 5 parts by mass of an allylated epoxy resin (Nippon Kayaku ( RE-810NM; epoxy equivalent 220), (C) 15 parts by mass of phenol / biphenylene resin (Maywa Kasei Co., Ltd., MEH-7851; hydroxyl equivalent 200, number average molecular weight 800), (D) 475 parts by mass of silver powder I (scale-like, tap density 6.4 g / cm ³ , specific surface area 0.2 m ² / g), 50 parts by mass of butyl carbitol acetate as a solvent, 1 part by mass of imidazole as a curing accelerator (Manufactured by Shikoku Kasei Kogyo Co., Ltd., 2MA-OK), 3-methacryloxypropyltrimethoxysila as a coupling agent The paste was adjusted by a conventional method using 1 part by mass. Using this paste, an optical semiconductor device was manufactured in the same manner as in Example 1.

(Comparative Example 1)
(A) Cresol novolac type epoxy resin 10 superimposed part (manufactured by Nippon Kayaku Co., Ltd., EOCN4500; epoxy equivalent 200) as solid epoxy resin at normal temperature, 15 parts by mass of phenol / biphenylene resin as solid phenolic resin (C) (Maywa Kasei Co., Ltd., MEH-7851; hydroxyl group equivalent 200, number average molecular weight 800), (D) 100 parts by weight of silver powder I (flaky, tap density 6.4 g / cm ³ , specific surface area 0.2 m ² / G), 50 parts by mass of butyl carbitol acetate as a solvent, 1 part by mass of imidazole as a curing accelerator (manufactured by Shikoku Kasei Kogyo Co., Ltd., 2MA-OK), 1 mass of 3-methacryloxypropyltrimethoxysilane as a coupling agent The paste was adjusted by a conventional method using the part. Using this paste, an optical semiconductor device was produced in the same manner as in Example 1.

(Comparative Example 2)
(A) 25 parts by mass of a cresol novolac type epoxy resin as a solid epoxy resin at normal temperature (manufactured by Nippon Kayaku Co., Ltd., EOCN4500; epoxy equivalent 200), 3 parts by mass of dicyandiamide (manufactured by Nippon Carbide Co., Ltd.), (D) 475 parts by mass of silver powder I (scale-like, tap density 6.4 g / cm ³ , specific surface area 0.2 m ² / g), 50 parts by mass of butyl carbitol acetate as a solvent, 1 part by mass of imidazole as a curing accelerator (Shikoku Kasei Kogyo Co., Ltd., 2MA-OK), 1 part by weight of 3-methacryloxypropyltrimethoxysilane was used as a coupling agent, and the paste was prepared by a conventional method. Using this paste, an optical semiconductor device was produced in the same manner as in Example 1.

(Comparative Example 3)
(A) 25 parts by mass of a cresol novolac type epoxy resin (manufactured by Nippon Kayaku Co., Ltd., EOCN4500; epoxy equivalent 200) as a solid epoxy resin at room temperature, 3 parts by mass of dicyandiamide (manufactured by Nippon Carbide Co., Ltd.), D) 100 parts by mass of silver powder II (scale-like, tap density 2.0 g / cm ³ , specific surface area 1.8 m ² / g), 50 parts by mass of butyl carbitol acetate as a solvent, 1 part by mass of imidazole as a curing accelerator ( Shikoku Kasei Kogyo Co., Ltd. 2MA-OK), 1 part by weight of 3-methacryloxypropyltrimethoxysilane was used as a coupling agent, and the paste was prepared by a conventional method. Using this paste, an optical semiconductor device was produced in the same manner as in Example 1.

  It confirmed about the following characteristic of the Example created above and a comparative example. The results are shown in Table 1.

(1) Adhesive strength with chip The adhesive strength between the chip (1 mm ² ) and the lead frame after reflow heat treatment at a top temperature of 260 ° C. after exposure for 72 hours in an environment of 85 ° C. and 85 RH% is expressed as follows: The adhesive strength was measured under the conditions of 260 ° C. and measurement method: die shear strength (unit: kgf / mm ² ).

(2) Thermal conductivity Using LF / TCM-FA8510B manufactured by Rigaku Corporation, the laser flash method was performed at a measurement temperature of 25 ° C. (unit: W / m · K).

(3) Electric resistivity It was carried out at a measurement temperature of 25 ° C. (unit: Ω · cm) with Iwatsu Measurement Co., Ltd. VOAC7523, a digital multimeter.

(4) Temperature rise of optical semiconductor device The surface temperature of the device immediately after 20 mA continuous energization at 20 ° C. for 100 hours was measured with a surface thermometer, and the difference from the temperature before energization was calculated (unit: ° C. ).

  As can be seen from Table 1, the optical semiconductor device of the example showed a good chip bond strength between the chip and the frame and a good shear failure mode without causing interface dissociation as compared with the comparative example. In addition, it showed high thermal conductivity and electrical conductivity, and it was found that it had good performance.

Claims (2)

In an optical semiconductor device in which a light emitting element chip is fixed to an upper surface of a substrate on which an electrode is formed via an adhesive layer, and the light emitting element chip is sealed,
The adhesive layer is (A) an epoxy resin that is solid at room temperature, (B) an allylated epoxy resin represented by the following general formula (I)

(In the formula, n is an integer of 0 to 1, X is the same or different and is selected from SO, SO ₂ , CH ₂ , C (CH ₃ ) ₂ , C (CF ₃ ) ₂ , O, CO and COO) Wherein R ^{1 to} R ⁸ are the same or different and are a hydrogen atom, an alkyl group which may have a substituent, or an allyl group which may have a substituent, at least one of which is a substituent. And (C) a solid phenolic curing agent at room temperature and (D) a specific surface area (SA) of 1.3 m ² / g or less and a tap density (TD) of 4. An optical semiconductor device formed of a resin paste for die bonding containing silver powder of 0.0 to 7.0 g / cm ³ . After the adhesive layer is exposed to an environment of 85 ° C. and 85% RH for 72 hours and further subjected to reflow treatment at 260 ° C., the adhesive strength with the lead frame is 1 kgf / mm ² or more, and the thermal conductivity is 20 W / m. The optical semiconductor device according to claim 1, wherein the optical semiconductor device has K or more and an electrical resistivity of 7 × 10 ⁻⁶ Ω · cm or less.