JP2013153175A - Method for suppressing discoloration of sealing resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical semiconductor device excellent in durability of reflection efficiency, in which discoloration of a cured product of an addition-curable silicone resin composition being a sealing resin is suppressed.SOLUTION: An addition-curable silicone resin composition being a sealing resin 7 inside a premolded package 2 constituting an optical semiconductor device 1 contains, as components, (A) an alkenyl group-containing organopolysiloxane, (B) an organohydrogenpolysiloxane having two or more hydrosilyl groups in one molecule, and (C) a catalyst. A molar ratio of the hydrosilyl groups in the component (B) to the alkenyl groups in the component (A) is 0.5-1.05.

Description

  The present invention relates to a method for suppressing discoloration of a sealing resin in an optical semiconductor device, and more specifically, it has excellent durability of reflection efficiency in which discoloration of a cured product of an addition-curable silicone resin composition that is a sealing resin is suppressed. The present invention relates to a method for suppressing discoloration of a sealing resin in an optical semiconductor device.

Recently, high-intensity light-emitting diodes (LEDs) with high light intensity and large heat generation have been commercialized and have been widely used.
Such an LED device is manufactured by using a cup-shaped pre-molded package integrally formed with a lead frame, mounting the LED therein, and sealing it with a sealing resin. Lead frames are usually plated with copper and used as a base material in order to ensure conductivity during LED mounting and increase the LED reflection efficiency, but the thickness of the silver plating is used to reduce manufacturing costs. Tends to be thin.
On the other hand, the sealing resin is required for the cured product to have transparency due to its properties, and generally from an epoxy resin such as a bisphenol A type epoxy resin or an alicyclic epoxy resin and an acid anhydride curing agent. An epoxy resin composition is used (see Patent Document 1: Japanese Patent No. 3241338, Patent Document 2: Japanese Patent Laid-Open No. 7-25987). However, the cured product of such an epoxy resin composition has a problem that it has low light resistance or is colored due to light deterioration because of its low transmittance of light having a short wavelength.
Accordingly, an organic compound containing at least two carbon-carbon double bonds having reactivity with a hydrosilyl group (SiH group), a silicon compound containing at least two SiH groups in one molecule, and hydrosilyl An addition-curable silicone resin composition comprising a fluorination catalyst has been proposed (see Patent Document 3: JP 2002-327126 A, Patent Document 4: JP 2002-338833 A). However, the cured product (sealing resin) of such an addition-curable silicone resin composition has a copper atom of the base material diffused into a thin silver plating layer in combination with the lead frame in which the thin silver plating is applied to the copper described above. However, since it reaches the surface of the silver plating or the sealing resin layer and changes its color to brown to cause a decrease in luminance, there is a problem that the quality of the LED device is deteriorated. That is, even if such an addition curable silicone resin composition is used, an LED device excellent in durability of reflection efficiency in which discoloration of the cured product is suppressed has not been obtained.

Japanese Patent No. 3241338 JP 7-25987 A JP 2002-327126 A JP 2002-338833 A

  The present invention has been made in view of the above circumstances, and the sealing resin in an optical semiconductor device excellent in durability of reflection efficiency in which discoloration of the cured product of the addition-curable silicone resin composition, which is a sealing resin, is suppressed. It aims at providing the discoloration suppression method.

  As a result of intensive investigations to achieve the above object, the present inventors have made a combination of a cured product (sealing resin) of an addition curable silicone resin composition and a lead frame in which thin silver plating is applied to copper. In copper It is considered that copper is precipitated by reacting with a group (SiH group), and the molar ratio of hydrosilyl group to alkenyl group in the addition-curable silicone resin composition is 0.5 to 1.05, so that copper is precipitated. It has been found that an optical semiconductor device excellent in the durability of reflection efficiency in which discoloration of the cured product is suppressed can be obtained, and the present invention has been made.

That is, the present invention provides the following sealing resin discoloration suppressing method.
Claim 1:
Inside the cup-shaped pre-molded package integrally molded so that a copper lead frame with a silver plating thickness of 0.5 to 2 μm is arranged on the inner bottom surface, the electrode of the optical semiconductor element is provided with a conductive adhesive or a conductive wire. The optical semiconductor element is mounted by connecting to the lead frame via the surface, or the electrodes of the optical semiconductor element are faced down via solder bumps and collectively connected to the lead frame to connect the optical semiconductor element to FC (Flip Chip). In an optical semiconductor device in which the inside of the pre-mold package is sealed with an addition-curable silicone resin composition and cured, copper is silver-plated from the lead frame and the addition-curable silicone resin composition. Diffusion reaches the sealing resin made of a cured product, and the copper oxide produced by the oxidation reaction is precipitated as copper. A method of inhibiting the sealing resin is discolored, as the addition-curable silicone resin composition,
(A) an alkenyl group-containing organopolysiloxane,
(B) Organohydrogenpolysiloxane having two or more hydrosilyl groups (SiH groups) in one molecule: molar ratio of hydrosilyl groups in component (B) to alkenyl groups in component (A) (SiH groups / alkenyl groups) ) Is 0.5 to 1.05,
(C) Catalyst: A method of suppressing discoloration of the encapsulating resin by suppressing the precipitation of copper using an addition-curable silicone resin composition containing a catalytic amount.
Claim 2:
The method according to claim 1, wherein the content of the silicone component in the pre-mold package is 15% by mass or more of the total organic components.
Claim 3:
The method according to claim 1 or 2, further comprising adding an adhesion-imparting agent to the addition-curable silicone resin composition.
Claim 4:
The method according to any one of claims 1 to 3, wherein a plasma treatment is performed on a silver-plated copper lead frame.

  ADVANTAGE OF THE INVENTION According to this invention, the optical semiconductor device excellent in durability of the reflective efficiency in which discoloration of the hardened | cured material of the addition curable silicone resin composition which is sealing resin was suppressed can be provided.

It is a schematic sectional drawing of the optical semiconductor device by an example of this invention. It is a schematic sectional drawing of the optical semiconductor device by another example of this invention.

Hereinafter, the present invention will be described in more detail.
1 and 2 are schematic cross-sectional views of optical semiconductor devices 1 and 1 'according to examples of the present invention.
The optical semiconductor device 1 includes an electrode of an optical semiconductor element (not shown) via a conductive adhesive 4 or a conductive wire 5 in a cup-shaped premolded package 2 that is integrally molded so that a lead frame 6 is disposed on the inner bottom surface. The optical semiconductor element 3 is mounted on the lead frame 6 and the inside of the premold package 2 is sealed with a sealing resin 7.
In the optical semiconductor device 1 ′, the electrode of the optical semiconductor element 3 (not shown) is faced down via a solder bump 8 in a cup-shaped premolded package 2 integrally molded so that the lead frame 6 is disposed on the inner bottom surface. The optical semiconductor element 3 is FC-mounted and connected to the lead frame 6 at the same time, and the inside of the premold package 2 is sealed with a sealing resin 7.
Here, the lead frame 6 is made of a base material copper plated with silver of 0.5 to 5 μm. Further, a cured product of an addition curable silicone resin composition is used for the sealing resin 7.

Such an addition-curable silicone resin composition is
(A) an alkenyl group-containing organopolysiloxane,
(B) Organohydrogenpolysiloxane having two or more hydrogen atoms bonded to silicon atoms in one molecule: molar ratio of hydrosilyl group (SiH group) in component (B) to alkenyl group in component (A) ( Amount of SiH group / alkenyl group) to be 0.5 to 1.05,
(C) Platinum-based catalyst: contains a catalyst amount.

Here, the molar ratio (SiH group / alkenyl group) is 0.5 to 1.05, more preferably 0.7 to 1.0, and still more preferably 0.8 to 0.99.
When the molar ratio is less than 0.5, the curing reaction of the composition does not proceed sufficiently and a sealing resin may not be obtained. If the molar ratio exceeds 1.05, a large amount of unreacted hydrosilyl groups remain in the cured product, so that the copper of the lead frame base material diffuses into the silver plating surface and the sealing resin, What became copper oxide by the oxidation reaction is returned to copper by the reduction reaction again. Such a redox reaction after diffusion of the lead frame base material to the silver-plated surface of copper or the sealing resin results in an accelerated copper elution reaction from the lead frame base material. Is changed from yellow to brown, which causes a decrease in luminance of the light emitting element of the optical semiconductor device.
On the other hand, by setting the molar ratio to 0.5 to 1.05, the curing reaction proceeds sufficiently so that it is sufficient as a sealing resin, and unreacted hydrosilyl groups do not remain in the cured product. Therefore, even if the copper of the lead frame base material diffuses on the silver plating surface, the reaction ends when it becomes copper oxide by the oxidation reaction, so the elution reaction of copper from the lead frame base material also ends. Thus, the sealing resin is not particularly discolored, and the luminance of the light emitting element of the optical semiconductor device is not lowered.

（式中、Ｒ¹は互いに同一又は異種の非置換もしくは置換の一価炭化水素基であり、Ｒ²は互いに同一又は異種の脂肪族不飽和結合を有さない非置換もしくは置換の一価炭化水素基であり、ｘ及びｙはそれぞれ０又は正の整数であり、ｘ＋ｙは０＜ｘ＋ｙ≦１０，０００を満足する０又は正の整数である。）
尚、この直鎖状オルガノポリシロキサンは少量の分岐状構造（三官能性シロキサン単位）を分子鎖中に含有するものであってもよい。また、粘度は例えば回転粘度計等により測定することができる。 Hereinafter, each component of the addition-curable silicone resin composition will be described.
(A) The alkenyl group-containing organopolysiloxane component (A) is a base component of the addition-curable silicone resin composition, and includes two or more (for example, 2 to 50) vinyl groups, allyl groups, etc. in one molecule. An organopolysiloxane having an alkenyl group having 2 to 8 carbon atoms, particularly 2 to 6 carbon atoms, preferably an alkenyl group bonded to a silicon atom.
Such an organosiloxane is generally a straight chain in which the main chain is composed of repeating diorganosiloxane units, and both ends of the molecular chain are blocked with a triorganosiloxy group. ), A linear organopolysiloxane having two or more alkenyl groups on the silicon atoms at both ends of the molecular chain, and having a viscosity of 10 to 1,000,000 mPa · s at 25 ° C., It is preferable from the viewpoint of curability and the like.

(In the formula, R ¹ is the same or different unsubstituted or substituted monovalent hydrocarbon group, and R ² is the same or different unsubstituted or unsubstituted monovalent hydrocarbon group. A hydrogen group, x and y are each 0 or a positive integer, and x + y is 0 or a positive integer satisfying 0 <x + y ≦ 10,000.)
The linear organopolysiloxane may contain a small amount of a branched structure (trifunctional siloxane unit) in the molecular chain. The viscosity can be measured by, for example, a rotational viscometer.

In the general formula (1), R ¹ preferably has 1 to 10 carbon atoms, particularly 1 to 6 carbon atoms, and specifically includes a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, and an isobutyl group. Alkyl groups such as tert-butyl group, pentyl group, neopentyl group, hexyl group, cyclohexyl group, octyl group, nonyl group, decyl group; aryl groups such as phenyl group, tolyl group, xylyl group, naphthyl group; benzyl group, Aralkyl groups such as phenylethyl group and phenylpropyl group; alkenyl groups such as vinyl group, allyl group, propenyl group, isopropenyl group, butenyl group, hexenyl group, cyclohexenyl group, octenyl group; and hydrogen atoms of these groups Some or all of them substituted with halogen atoms such as fluorine, bromine, chlorine, cyano groups, etc., for example, chloromethyl , Chloropropyl group, bromoethyl group, a halogen-substituted alkyl groups such as trifluoropropyl group, and cyanoethyl group and the like.

R ² preferably has 1 to 10 carbon atoms, particularly 1 to 6 carbon atoms, and the same examples as the specific examples of R ¹ described above, but does not include an aliphatic unsaturated bond such as an alkenyl group. .

  x and y are 0 or a positive integer satisfying 0 <x + y ≦ 10,000, preferably 5 ≦ x + y ≦ 2,000, and an integer satisfying 0 <x / (x + y) ≦ 0.2. is there.

（式中、ｔはそれぞれ独立に８〜２，０００の整数である。） Specific examples of the organopolysiloxane represented by the general formula (1) include the following.

(In the formula, t is each independently an integer of 8 to 2,000.)

（上記式において、ｘ及びｙは上述した通りである。）

(In the above formula, x and y are as described above.)

The organopolysiloxane represented by the general formula (1) can be used in combination with an organopolysiloxane having a resin structure, that is, a three-dimensional network structure.
The organopolysiloxane having this resin structure (that is, a three-dimensional network structure) is composed of SiO ₂ units, R ³ _k R ⁴ _p SiO _0.5 units and R ³ _q R ⁴ _r SiO _0.5 units (in the above formula, R ³ represents Vinyl group or allyl group, R ⁴ is an unsubstituted or substituted monovalent hydrocarbon group not containing an aliphatic unsaturated bond, k is 2 or 3, p is 0 or 1, k + p = 3, q is 0 Or 1, r is 2 or 3, and q + r = 3).
Examples of the monovalent hydrocarbon group for R ⁴ include those having 1 to 10 carbon atoms, particularly 1 to 6 carbon atoms, similar to the above R ² .

Here, organopolysiloxane resin structure, when the SiO ₂ unit a ^{_{unit, R 3 k R 4 p SiO}} 0.5 units b units, the _R ³ _q R ⁴ _r SiO _0.5 units and c units, these units ratio Is preferably (b + c) /a=0.3-3, especially 0.7-1, c / a = 0.01-1, particularly 0.07-0.15, The organopolysiloxane preferably has a polystyrene-equivalent weight average molecular weight in the range of 500 to 10,000 by GPC.

  In addition to the a unit, b unit and c unit, the resin-structured organopolysiloxane further comprises a bifunctional siloxane unit or a trifunctional siloxane unit, that is, an organosilsesquioxane unit. It may be contained in a small amount within a range that does not impair.

  Such an organopolysiloxane having a resin structure can be easily synthesized by combining the compounds serving as the unit sources so as to have the above molar ratio, for example, by performing co-hydrolysis in the presence of an acid.

  Here, examples of the a unit source include sodium silicate, alkyl silicate, polyalkyl silicate, and silicon tetrachloride.

Examples of the b unit source include the following.

Examples of the c unit source include the following.

  Such an organopolysiloxane having a resin structure is blended in order to improve the physical strength and surface tackiness of the cured product, and is blended in an amount of 20 to 70% by mass in the component (A). More preferably, it is mix | blended in the quantity of 30-60 mass%. When the blending amount is less than 20% by mass, the above effect may not be sufficiently achieved. When the blending amount is more than 70% by mass, the viscosity of the composition may be remarkably increased or cracks may easily occur in the cured product. is there.

(B) The organohydrogenpolysiloxane component (B) is a crosslinking agent component, and a cured product is formed by an addition reaction between the hydrosilyl group (SiH group) in the component and the alkenyl group in the component (A). Organohydrogenpolysiloxane.
Such organohydrogenpolysiloxane may be any one as long as it has 2 or more, preferably 3 or more hydrosilyl groups (SiH groups) in one molecule. It is preferable to have at least two (usually 2 to 300), preferably 3 or more (for example, 3 to 200) hydrogen atoms (SiH groups) bonded to silicon atoms in one molecule.
H _a (R ⁵ ) _b SiO _{(4-ab) / 2} (2)
Wherein R ⁵ is the same or different unsubstituted or substituted monovalent hydrocarbon group containing no aliphatic unsaturated bond, and a and b are 0.001 ≦ a <2, 0.7 ≦ b ≦ 2 and 0.8 ≦ a + b ≦ 3.)

In the general formula (2), R ⁵ is the same or different unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms, particularly 1 to 7 carbon atoms, which does not contain an aliphatic unsaturated bond. Examples thereof include those exemplified for the substituent R ² in the general formula (1), such as a lower alkyl group such as a methyl group and an aryl group such as a phenyl group.
A and b are numbers satisfying 0.001 ≦ a <2, 0.7 ≦ b ≦ 2, and 0.8 ≦ a + b ≦ 3, preferably 0.05 ≦ a ≦ 1, 0.8 ≦ b ≦ 2 and 1 ≦ a + b ≦ 2.7. The position of the hydrogen atom bonded to the silicon atom is not particularly limited and may be the terminal or non-terminal of the molecule.

Such organohydrogenpolysiloxanes include tris (dimethylhydrogensiloxy) methylsilane, tris (dimethylhydrogensiloxy) phenylsilane, 1,1,3,3-tetramethyldisiloxane, 1,3,5,7. -Tetramethylcyclotetrasiloxane, both ends trimethylsiloxy group-blocked methylhydrogenpolysiloxane, both ends trimethylsiloxy group-blocked dimethylsiloxane / methylhydrogensiloxane copolymer, both ends dimethylhydrogensiloxy group-blocked dimethylpolysiloxane, both ends Dimethylhydrogensiloxy group-capped dimethylsiloxane / methylhydrogensiloxane copolymer, both ends trimethylsiloxy group-capped methylhydrogensiloxane / diphenylsiloxane Polymers, both end trimethylsiloxy-blocked methylhydrogensiloxane-diphenylsiloxane-dimethylsiloxane copolymer, (CH ₃₎ consists of ₂ HSiO _1/2 units and SiO _4/2 units, copolymers composed, (CH ₃₎ Examples thereof include copolymers comprising ₂ HSiO _1/2 units, SiO _4/2 units, and (C ₆ H ₅ ) SiO _3/2 units.

Moreover, the organohydrogenpolysiloxane obtained using the unit shown by the following structure can also be used.

Examples of such organohydrogenpolysiloxanes include the following.

  Thus, the molecular structure of the organohydrogenpolysiloxane of component (B) may be any of linear, cyclic, branched, and three-dimensional network structures, but the number of silicon atoms in one molecule ( Or the degree of polymerization) can be 3 to 1,000, particularly about 3 to 300.

Such organohydrogenpolysiloxanes are usually R ⁵ SiHCl ₂ , (R ⁵ ) ₃ SiCl, (R ⁵ ) ₂ SiCl ₂ , (R ⁵ ) ₂ SiHCl (R ⁵ is as described above). Such chlorosilanes can be hydrolyzed or siloxanes obtained by hydrolysis can be equilibrated.

(C) The catalyst component (C) is a catalyst that causes an addition curing reaction of the addition curing reaction type silicone resin composition.
Such catalysts include platinum-based, palladium-based, and rhodium-based catalysts. From the viewpoint of cost and the like, platinum-based catalysts such as platinum, platinum black, and chloroplatinic acid, for example, H ₂ PtCl ₆ · mH. ₂ O, K ₂ PtCl ₆ , KHPtCl ₆ · mH ₂ O, K ₂ PtCl ₄ , K ₂ PtCl ₄ · mH ₂ O, PtO ₂ · mH ₂ O (m is a positive integer), and these, olefins, etc. And a complex with a hydrocarbon, alcohol, or vinyl group-containing organopolysiloxane. These can be used alone or in combination of two or more.

  The compounding amount of these catalyst components is a curing effective amount and may be a so-called catalyst amount, and is usually 0.1 to 0.1 parts by mass in terms of platinum group metal per 100 parts by mass of the total amount of the components (A) and (B). It is used in the range of 1,000 ppm, particularly 0.5 to 200 ppm.

(D) Other components The addition-curable silicone resin composition used in the present invention contains the above-described components (A) to (C) as essential components, and various known additives may be added thereto as necessary. You may mix | blend.
Examples of such additives include reinforcing inorganic fillers such as fumed silica and fumed titanium dioxide, and non-reinforcing inorganic fillers such as calcium carbonate, calcium silicate, titanium dioxide, ferric oxide, carbon black, and zinc oxide. Agents, antioxidants such as BHT and vitamin B, photodegradation inhibitors such as hindered amines, reactive diluents such as vinyl ethers, vinyl amides, epoxy resins, oxetanes, allyl phthalates, vinyl adipate, and the like.

In addition, as an adhesion-imparting agent, vinyltrimethoxysilane, vinyltriethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldi Ethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, N-2 (aminoethyl) 3-aminopropylmethyldimethoxysilane, N-2 (aminoethyl) 3-aminopropyltrimethoxysilane, N-2 (aminoethyl) 3-aminopropyltriethoxysilane, 3-aminopro Le trimethoxysilane, 3-aminopropyl triethoxysilane, N- phenyl-3-aminopropyl trimethoxysilane, and 3-mercaptopropyl trimethoxysilane, trimethoxysilane, tetramethoxysilane and oligomers thereof, and the like. These adhesion-imparting agents can be used alone or in admixture of two or more.
The compounding amount of the adhesion-imparting agent is preferably 10% by mass or less (0 to 10% by mass), particularly 5% by mass or less (0 to 5% by mass) of the entire composition.

The addition curable silicone resin composition, such as a method for preparing an addition curable silicone resin composition, is prepared by adding the above components (A) to (C) and the desired other components simultaneously or separately, if necessary. It can be obtained by stirring, dissolving, mixing, and dispersing.
However, the components (A) and (C) and the component (B) are usually stored in two liquids so that the curing reaction does not proceed before use, and the two liquids are mixed and cured at the time of use. . The reason why the two liquids are divided is that the same blending of the component (B) and the component (C) must be avoided from the risk of dehydrogenation reaction. Further, a small amount of a curing inhibitor such as acetylene alcohol can be added and used as one liquid.
Although the apparatus used for operations, such as stirring, is not specifically limited, A raikai machine provided with stirring and a heating apparatus, 3 rolls, a ball mill, a planetary mixer etc. can be used. Moreover, you may combine these apparatuses suitably.
In addition, as for the viscosity in 25 degreeC measured with the rotational viscometer of the obtained addition curable silicone resin composition, about 100-10,000,000 mPa * s is preferable about 300-500,000 mPa * s.

  The addition curable silicone resin composition thus obtained is cured immediately by heating if necessary, has high transparency, and adheres very well to package materials such as LCP and metal substrates. This is effective for sealing an optical semiconductor element. Examples of the optical semiconductor element include an LED, a photodiode, a CCD, a CMOS, a photocoupler, and the like, and are particularly effective for sealing an LED.

As the sealing method, a known method according to the type of the optical semiconductor element is adopted, and the curing conditions of the addition-curable silicone resin composition are not particularly limited, but usually 40 to 250 ° C., preferably Can be cured at 60 to 200 ° C. for 5 minutes to 10 hours, preferably about 30 minutes to 6 hours.
The silver-plated lead frame is preferably subjected to a surface treatment in advance in order to improve the wettability of the addition curable silicone resin composition. Such surface treatment is preferably a dry method such as ultraviolet treatment, ozone treatment, plasma treatment, etc. from the viewpoints of workability and equipment maintenance, and plasma treatment is particularly preferred.
Further, the material of the pre-mold package is preferably such that the content of the silicone component in the pre-mold package is 15% by mass or more of the total organic components in order to improve the compatibility of the addition-curable silicone resin composition. The silicone component here is defined as a compound having a Si unit and a polymer thereof, and if this is less than 15% by mass of the total organic component, the compatibility of the addition-curable silicone resin composition is lowered. When sealing with resin, a gap (air bubbles) is formed between the addition-curable silicone resin composition and the inner wall of the pre-mold package, and as a result, an optical semiconductor device that is easily cracked is not preferable.

  The optical semiconductor device sealed with the cured product of the addition-curable silicone resin composition obtained in this way has no unreacted hydrosilyl group remaining in the cured product as described above. It is possible to provide an optical semiconductor device excellent in durability of reflection efficiency in which discoloration of the cured product is suppressed.

  EXAMPLES Hereinafter, although this invention is demonstrated concretely based on an Example and a comparative example, this invention is not limited to the following Example.

[Examples 1 to 3, Comparative Examples 1 and 2]
The following various materials were blended as shown in Table 1, and uniformly kneaded to obtain various addition-curable silicone resin compositions. By heating and molding this at 150 ° C. for 4 hours, 124 mm ( Various test pieces of (length) × 110 mm (width) × 1 mm (thickness) were produced.
Using the test piece thus obtained, 450 nm wavelength light was irradiated in the thickness direction, and the light transmission appearance was visually observed. Further, based on JIS K 6301, tensile strength, hardness (measured using an A-type spring tester) and elongation were measured.
The results are also shown in Table 1.

２）ビニルメチルシロキサン（ＶＭＱ）：ＳｉＯ₂単位５０モル％、（ＣＨ₃）₃ＳｉＯ_0.5単位４２．５モル％及びＶｉ₃ＳｉＯ_0.5単位７．５モル％からなるレジン構造を有するビニルメチルシロキサン
３）ハイドロジェンポリシロキサン：下記式（ｉｉ）で表されるハイドロジェンポリシロキサン

４）白金触媒：塩化白金酸のオクチルアルコール変性溶液（白金濃度２質量％）
ｅ）接着付与剤：下記式（ｉｉｉ）で表される接着付与剤

[Materials used]
1) Polysiloxane (VF): polysiloxane represented by the following formula (i)

2) Vinylmethylsiloxane (VMQ): vinylmethylsiloxane 3 having a resin structure composed of 50 mol% of SiO ₂ units, 42.5 mol% of (CH ₃ ) ₃ SiO _0.5 units and 7.5 mol% of Vi ₃ SiO _0.5 units ) Hydrogen polysiloxane: hydrogen polysiloxane represented by the following formula (ii)

4) Platinum catalyst: octyl alcohol modified solution of chloroplatinic acid (platinum concentration 2% by mass)
e) Adhesive agent: Adhesive agent represented by the following formula (iii)

  As shown in Table 1, for Examples 1 to 3 and Comparative Example 2, sufficient physical properties (hardness, tensile strength, elongation) were observed. On the other hand, with respect to Comparative Example 1, sufficient physical properties were not observed, and particularly tensile strength and elongation could not be measured.

Moreover, the LED device was produced and evaluated using the various addition-curable silicone resin compositions of Examples 1 to 3 and Comparative Examples 1 and 2.
That is, Ar plasma under reduced pressure was applied to a cup-shaped LED pre-molded package (3 mm x 3 mm x 1 mm, opening diameter 2.6 mm) with a copper lead frame with a silver plating of 2 µm on the bottom. (Output: 100 W, irradiation time: 10 seconds) Processing is performed, and an electrode of an InGaN blue light emitting element is connected to the lead frame on the bottom surface using a silver paste (conductive adhesive), and a counter electrode of the light emitting element is connected It was connected to the counter lead frame with a gold wire, filled with various addition-curable silicone resin compositions into the package opening, cured at 60 ° C. for 1 hour, and further cured at 150 ° C. for 4 hours and sealed.
The LED device thus obtained was allowed to stand for 500 hours in an atmosphere of 150 ° C. while being lit by flowing a current of 25 mA, and then the degree of discoloration near the silver plating surface in the package was visually examined.
The results are shown in Table 2.

  As shown in Table 2, for Examples 1 to 3, no discoloration in the vicinity of the silver plating surface in the package was observed. On the other hand, about the comparative example 2, the silver plating surface vicinity in a package has yellowed, and the fall of the emitted light intensity clear by visual observation was recognized with respect to Examples 1-3. Moreover, about the comparative example 1, although the silver plating surface vicinity in a package was slightly yellowing, the fall of the light emission intensity clear by visual observation was not recognized with respect to Examples 1-3.

DESCRIPTION OF SYMBOLS 1 Optical semiconductor device 2 Premold package 3 Optical semiconductor element 4 Conductive adhesive 5 Conductive wire 6 Silver plating lead frame 7 Sealing resin 8 Solder bump

Claims (4)

Inside the cup-shaped pre-molded package integrally molded so that a copper lead frame with a silver plating thickness of 0.5 to 2 μm is arranged on the inner bottom surface, the electrode of the optical semiconductor element is provided with a conductive adhesive or a conductive wire. The optical semiconductor element is mounted by connecting to the lead frame via the surface, or the electrodes of the optical semiconductor element are faced down via solder bumps and collectively connected to the lead frame to connect the optical semiconductor element to FC (Flip Chip). In an optical semiconductor device in which the inside of the pre-mold package is sealed with an addition-curable silicone resin composition and cured, copper is silver-plated from the lead frame and the addition-curable silicone resin composition. Diffusion reaches the sealing resin made of a cured product, and the copper oxide produced by the oxidation reaction is precipitated as copper. A method of inhibiting the sealing resin is discolored, as the addition-curable silicone resin composition,
(A) an alkenyl group-containing organopolysiloxane,
(B) Organohydrogenpolysiloxane having two or more hydrosilyl groups (SiH groups) in one molecule: molar ratio of hydrosilyl groups in component (B) to alkenyl groups in component (A) (SiH groups / alkenyl groups) ) Is 0.5 to 1.05,
(C) Catalyst: A method of suppressing discoloration of the encapsulating resin by suppressing the precipitation of copper using an addition-curable silicone resin composition containing a catalytic amount.   The method according to claim 1, wherein the content of the silicone component in the pre-mold package is 15% by mass or more of the total organic components.   The method according to claim 1 or 2, further comprising adding an adhesion-imparting agent to the addition-curable silicone resin composition.   The method according to any one of claims 1 to 3, wherein a plasma treatment is performed on a silver-plated copper lead frame.

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