JP7321969B2 - Thermosetting silicone resin composition and die attach material for optical semiconductor device - Google Patents

Description

The present invention relates to a thermosetting silicone resin composition and a die attach material for optical semiconductor devices.

Optical semiconductors (LEDs) have rapidly spread in recent years due to their advantages of low power consumption and long life compared to conventional light emitting devices such as light bulbs and fluorescent lamps. When manufacturing an optical semiconductor device, first, a curable resin composition called a die attach material is applied to a predetermined position on an optical semiconductor substrate for the purpose of fixing an optical semiconductor chip to the substrate. There are two methods of applying the die attach material: the dispensing method, in which the resin filled in the syringe is applied with pressure from the needle attached to the tip of the syringe, and the resin is transferred onto the substrate; There are generally two methods of stamping, in which pins are pressed and then pins with resin adhered are pressed and transferred onto a substrate. Then, a die-bonding process is performed to pressure-bond an LED chip whose bottom part is mostly made of sapphire to the top of the applied resin composition, and then, through a process of curing the resin composition, most of which is made of gold. A wire bonding process is performed to bond the electrode pad portion of the optical semiconductor chip and the conductive lead frame portion formed mostly of silver on the substrate with a gold wire. In the wire bonding process, the gold ball formed at the tip of the capillary is pressed against the electrode pad while applying ultrasonic waves. is diffused to the surroundings, and the problem arises that the gold wire cannot be joined with sufficient strength. In addition, if the LED chip floats from the substrate during the lighting operation after the LED device is manufactured through the post-process, heat cannot be sufficiently dissipated from the LED chip, which is a heating element, to the substrate, which may cause malfunction. be. For this reason, a curable resin composition capable of imparting a cured product with high strength and high adhesion is used as the die attach material in order to sufficiently fix the LED chip to the substrate.

In addition, addition-curable silicone resin compositions such as methyl silicone are often used as die attach materials in high-output blue LED devices, which are often used for lighting applications, from the viewpoint of imparting heat resistance and light resistance. However, it has been pointed out that the bonding strength is low due to the strength of the resin compared to organic resins such as silver pastes using epoxy resins as binders used in red LED devices. In particular, recently, COB type blue LED devices with multiple LED chips mounted on one substrate have emerged. Blue LED chips of a certain small size are often used, but there is also the problem that conventional methyl silicone-based addition-curable silicone resin compositions cannot meet the required holding power of the LED chips in the wire bonding process. .

As described above, conventional addition-curable silicone resin compositions such as those listed in Patent Document 1 and Patent Document 2, when used as a die attach material for an LED device, have insufficient adhesive strength, especially for small-sized LED chips. There was a problem of enough.

JP 2018-131583 A International Publication 2018/155131

The present invention was made in order to solve the above problems, and it is an object of the present invention to obtain a thermosetting silicone resin composition that provides a resin cured product with high hardness and resin strength and that has excellent adhesion to substrates. With the goal.

（式中、Ｒ^１及びＲ^２はそれぞれ上記と同じであり、Ｒ^３は前記Ｒ^１又は前記Ｒ^２から選ばれる基であり、１分子中の２個以上がＲ^１であり、２≦ｋ１＜２０、０≦ｋ２＜１０である）
で示される直鎖状オルガノポリシロキサン、
（Ｂ）下記式（３）
（Ｒ^４Ｒ^２ _２ＳｉＯ_１／２）_２（ＨＲ^２ＳｉＯ_２／２）_ｘ（Ｒ^２ _２ＳｉＯ_２／２）_ｙ （３）
（式中、Ｒ^２はそれぞれ上記と同じであり、Ｒ^４は水素原子又はＲ^２で示される基であり、ｘ及びｙはｘ＞０、ｙ＞０であり、０．６０≦（ｘ／（ｘ＋ｙ））≦０．９５であり、かつ、３０≦ｘ＋ｙ≦１２０となる数である。）
で示される直鎖状オルガノハイドロジェンポリシロキサン、
（Ｃ）付加硬化触媒
を必須成分として含有するものであることを特徴とする熱硬化性シリコーン樹脂組成物を提供する。 In order to achieve the above objects, the present invention provides the following components (A-1), (A-2), (B), and (C),
(A-1) Formula (1) below
(R ¹ _n R ² _3-n SiO _1/2 ) _a (HR ² ₂ SiO _1/2 ) _b (R ² ₃ SiO _1/2 ) _c (R ² ₂ SiO _2/2 ) _d (R ² SiO _{3 /2} ) _e (1)
(wherein R ¹ is an alkenyl group having 2 to 8 carbon atoms, R ² is independently an alkyl group having 1 to 12 carbon atoms, and 0.01<a<0.15, 0.05<b<0 .2, 0≦c<0.1, 0≦d<0.1, 0.45<e<0.94, provided that a+b+c+d+e=1 and n is an integer from 1 to 3 is.)
A branched organopolysiloxane represented by and having two or more alkenyl groups having 2 to 8 carbon atoms in one molecule and having two or more hydrogen atoms directly bonded to silicon atoms in one molecule,
(A-2) Formula (2) below

(In the formula, R ¹ and R ² are the same as above, R ³ is a group selected from R ¹ or R ² , two or more R ¹ in one molecule, 2 ≤ k1 <20, 0≤k2<10)
A linear organopolysiloxane represented by
(B) Formula (3) below
( ^R4R22SiO1 _/2 ⁾ _{2 (} ^HR2SiO2 _/2 ) _x ( ^R22SiO2 _{/ 2} ) _y (3)
(wherein R ² is the same as above, R ⁴ is a hydrogen atom or a group represented by R ² , x and y are x>0, y>0, and 0.60≦(x/ (x + y)) ≤ 0.95 and 30 ≤ x + y ≤ 120.)
A linear organohydrogenpolysiloxane represented by
(C) A thermosetting silicone resin composition containing an addition curing catalyst as an essential component.

With such a thermosetting silicone resin composition, a cured resin product having high hardness and resin strength can be obtained, and the adhesive strength to the substrate is excellent.

Further, in the present invention, the thermosetting silicone resin composition wherein 90 mol % or more of all R ² in the R ² of the components (A-1), (A-2) and (B) are methyl groups. is preferred.

Such a thermally conductive silicone composition is excellent in discoloration resistance when left for a long time under high temperature conditions or under blue light with a wavelength of 450 nm.

Further, in the present invention, the following formula (4) is further used as (D) an adhesion aid
(MeSiO3 _/2 ) _p1 (EpSiO3 _/2 ) _p2 (EpMeSiO2 _/2 ) _q1 (Me2SiO2 _{/2 ) q2} (ViMeSiO2 _/2 ) _q3 ( ^OR5 ) _r (4)
(In the formula, Me is a methyl group, Ep is a monovalent organic group having an epoxy group, Vi is a vinyl group, R ⁵ is an alkyl group having 1 to 12 carbon atoms, and 0≤p1< 0.35, 0≤p2<0.35, 0≤q1<0.35, 0.4≤q2<0.7, 0<q3<0.1, 0≤r<0.05, and 0. 15≦(p2+q1)/(p1+p2+q1+q2+q3+r)≦0.35, provided that p1+p2+q1+q2+q3+r=1.)
A branched organopolysiloxane having a weight average molecular weight of 1,500 to 6,000 and an epoxy equivalent of 250 to 500 g/eq. It is preferably a thermosetting silicone resin composition that

With such a thermally conductive silicone composition, it is possible to suppress discoloration when left for a long time under high temperature conditions or under blue light with a wavelength of 450 nm.

The present invention also provides a die attach material for an optical semiconductor device comprising the thermosetting silicone resin composition.

With such a die attach material for an optical semiconductor device, it is possible to provide a highly reliable LED device because the bonding strength is excellent even for a small-sized LED chip.

According to the thermosetting silicone resin composition of the present invention, when used as an LED die attach material, it is possible to provide a highly reliable LED device because it has excellent adhesive strength even with small-sized LED chips. Therefore, the thermosetting silicone resin composition of the present invention is extremely useful as a die attach material for LEDs.

In addition, as a reason for expressing such an effect, by using the above-mentioned specific organopolysiloxane in a specific combination, resin curing with high hardness and resin strength compared to ordinary thermosetting silicone resin compositions It is considered that a product can be obtained and that the adhesiveness to the substrate is excellent.

As described above, there has been a demand for the development of a thermosetting silicone resin composition that yields a resin cured product with high hardness and resin strength and that has excellent adhesion to substrates.

The inventors of the present invention conducted intensive studies to achieve the above object, and found that a thermosetting silicone resin composition containing the following components (A-1) to (C) was used as a die attach material for an optical semiconductor device. When used, the inventors have found that even small-sized LED chips have excellent adhesiveness, and have completed the present invention.

（式中、Ｒ^１及びＲ^２はそれぞれ上記と同じであり、Ｒ^３は前記Ｒ^１又は前記Ｒ^２から選ばれる基であり、１分子中の２個以上がＲ^１であり、２≦ｋ１＜２０、０≦ｋ２＜１０である）
で示される直鎖状オルガノポリシロキサン、
（Ｂ）下記式（３）
（Ｒ^４Ｒ^２ _２ＳｉＯ_１／２）_２（ＨＲ^２ＳｉＯ_２／２）_ｘ（Ｒ^２ _２ＳｉＯ_２／２）_ｙ （３）
（式中、Ｒ^２はそれぞれ上記と同じであり、Ｒ^４は水素原子又はＲ^２で示される基であり、ｘ及びｙはｘ＞０、ｙ＞０であり、０．６０≦（ｘ／（ｘ＋ｙ））≦０．９５であり、かつ、３０≦ｘ＋ｙ≦１２０となる数である。）
で示される直鎖状オルガノハイドロジェンポリシロキサン、
（Ｃ）付加硬化触媒
を必須成分として含有するものであることを特徴とする熱硬化性シリコーン樹脂組成物である。 That is, the present invention provides the following components (A-1), (A-2), (B), and (C),
(A-1) Formula (1) below
(R ¹ _n R ² _3-n SiO _1/2 ) _a (HR ² ₂ SiO _1/2 ) _b (R ² ₃ SiO _1/2 ) _c (R ² ₂ SiO _2/2 ) _d (R ² SiO _{3 /2} ) _e (1)
(wherein R ¹ is an alkenyl group having 2 to 8 carbon atoms, R ² is independently an alkyl group having 1 to 12 carbon atoms, and 0.01<a<0.15, 0.05<b<0 .2, 0≦c<0.1, 0≦d<0.1, 0.45<e<0.94, provided that a+b+c+d+e=1 and n is an integer from 1 to 3 is.)
A branched organopolysiloxane represented by and having two or more alkenyl groups having 2 to 8 carbon atoms in one molecule and having two or more hydrogen atoms directly bonded to silicon atoms in one molecule,
(A-2) Formula (2) below

(In the formula, R ¹ and R ² are the same as above, R ³ is a group selected from R ¹ or R ² , two or more R ¹ in one molecule, 2 ≤ k1 <20, 0≤k2<10)
A linear organopolysiloxane represented by
(B) Formula (3) below
( ^R4R22SiO1 _/2 ⁾ _{2 (} ^HR2SiO2 _/2 ) _x ( ^R22SiO2 _{/ 2} ) _y (3)
(wherein R ² is the same as above, R ⁴ is a hydrogen atom or a group represented by R ² , x and y are x>0, y>0, and 0.60≦(x/ (x + y)) ≤ 0.95 and 30 ≤ x + y ≤ 120.)
A linear organohydrogenpolysiloxane represented by
(C) A thermosetting silicone resin composition characterized by containing an addition curing catalyst as an essential component.

Although the present invention will be described in detail below, the present invention is not limited thereto.

The thermosetting silicone resin composition of the present invention contains the above (A-1) to (C), and if necessary, may further contain various known additives. Each component will be described below.

<(A-1) Branched Organopolysiloxane>
Component (A-1) is represented by the following formula (1), has two or more alkenyl groups having 2 to 8 carbon atoms in one molecule, and is directly bonded to two or more silicon atoms in one molecule. It is a branched organopolysiloxane having hydrogen atoms.
(R ¹ _n R ² _3-n SiO _1/2 ) _a (HR ² ₂ SiO _1/2 ) _b (R ² ₃ SiO _1/2 ) _c (R ² ₂ SiO _2/2 ) _d (R ² SiO _{3 /2} ) _e (1)
(In the formula, R ¹ is an alkenyl group having 2 to 8 carbon atoms, R ² is independently an alkyl group having 1 to 12 carbon atoms, and the mole fraction (content) a to e of the repeating unit is 0 .01<a<0.15, 0.05<b<0.2, 0≤c<0.1, 1, 0≤d<0.1, 0.45<e<0.94, with the proviso that , a+b+c+d+e=1, and n is an integer from 1 to 3.)

In the above formula (1), the alkenyl group of R ¹ preferably having 2 to 8 carbon atoms, particularly preferably 2 to 6 carbon atoms, specifically includes a vinyl group, an allyl group, an isopropenyl group, a butenyl group, a pentenyl group, and a hexenyl group. group, cyclohexenyl group, etc., and vinyl group is particularly preferred.

In the above formula (1), the alkyl group of R ² preferably has 1 to 12 carbon atoms, particularly preferably 1 to 10 carbon atoms, specifically, a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, and an isobutyl group. , tert-butyl group, pentyl group, neopentyl group, hexyl group, cyclohexyl group, octyl group, nonyl group, decyl group and the like. Considering the discoloration resistance of the cured silicone product produced from the resulting thermosetting silicone resin composition under high temperature conditions or under blue light with a wavelength of 450 nm for a long period of time, the alkyl group for R ² is selected as the alkyl group for R 2 . , methyl group, ethyl group, propyl group and isopropyl group are preferred, and methyl group is particularly preferred.

Thus, an organopolysiloxane having R ₃ SiO _1/2 units (M units) having alkenyl groups and hydrosilyl groups and RSiO _3/2 units (T units) as a resin source has conventional alkenyl groups. It is possible to give a cured product having a high resin strength compared to an organopolysiloxane that uses R ₃ SiO _1/2 units (M units) and SiO _4/2 units (Q units) as a resin source. Since the curing reaction progresses mildly, it is possible to improve the adhesion to the substrate.

Further, the content a of the R ¹ _n R ² _3-n SiO _1/2 units in the above formula (1) is in the range of 0.01<a<0.15 with respect to the total of siloxane units a+b+c+d+e=1. and preferably in the range of 0.02≤a≤0.14. The content b of HR ² ₂ SiO _1/2 units is in the range of 0.05<b<0.2, preferably 0.08≦b≦0, with respect to the total of siloxane units a+b+c+d+e=1. .18 range. Further, the above content c of R ² ₃ SiO _1/2 units is in the range of 0≦c<0.1, preferably in the range of 0≦c≦0.08, with respect to the total of siloxane units a+b+c+d+e=1. is. The content d of R ² ₂ SiO _2/2 units is in the range of 0≦d<0.1, preferably 0≦d≦0.08, with respect to the total of siloxane units a+b+c+d+e=1. is. Further, the content e of the R ² SiO _3/2 units is in the range of 0.45<e<0.94, preferably 0.5≦e≦0, with respect to the total of the siloxane units a+b+c+d+e=1. .9 range.

The above component (A-1) can be easily synthesized by mixing each unit source compound at a content ratio within the above range and performing cohydrolytic condensation, for example, in the presence of an acid.

Examples of the R ¹ _n R ² _3-n SiO _1/2 unit source include organosilicon compounds such as triorganochlorosilanes, triorganoalkoxysilanes and hexaorganodisiloxanes represented by the following structural formulas. The sources of R ¹ _n R ² _3-n SiO _1/2 units that can be used are not limited to these. n is an integer of 1-3.

Here, the HR ² ₂ SiO _1/2 unit source can be exemplified by organosilicon compounds such _as tetraorganodisiloxane represented by _the following structural formula ^. Not limited.

Here, examples _of the R ² ₃ SiO _1/2 unit source include organosilicon compounds such as hexaorganodisiloxane represented by ^the following structural formula _. Not limited.

_Examples of the R ² ₂ SiO _2/2 unit source include organosilicon compounds such as diorganodialkoxysilanes represented by _the following structural formulas ^. is not limited to

Here, examples of the R ² SiO _3/2 unit source include organosilicon compounds such as monoorganotrichlorosilane and monoorganotrialkoxysilane represented by the following structural formulas, and usable R ² SiO _3/2 units Sources are not limited to these.

The properties of component (A-1) are not particularly limited, but are preferably liquid at 25°C.

The weight average molecular weight of component (A-1) is preferably in the range of 4,000 to 12,000, more preferably in the range of 6,000 to 10,000. The weight-average molecular weight referred to in the present invention refers to the weight-average molecular weight measured by gel permeation chromatography (GPC) under the following conditions using polystyrene as a standard substance.

[Measurement condition]
・ Developing solvent: tetrahydrofuran (THF)
・Flow rate: 0.6mL/min
・ Detector: Differential refractive index detector (RI)
・Column: TSK Guard column SuperH-L
・TSKgel Super H4000 (6.0mm I.D. x 15cm x 1)
・TSKgel Super H3000 (6.0mm I.D. x 15cm x 1)
・TSKgel Super H2000 (6.0mm I.D. x 15cm x 2)
(both manufactured by Tosoh Corporation)
・Column temperature: 40°C
・ Sample injection volume: 20 μL (THF solution with a concentration of 0.5% by mass)

（式中、Ｒ^１及びＲ^２はそれぞれ上記と同じであり、Ｒ^３は前記Ｒ^１又は前記Ｒ^２から選ばれる基であり、１分子中の２個以上がＲ^１であり、２≦ｋ１＜２０、０≦ｋ２＜１０である。） <(A-2) Linear Organopolysiloxane>
Component (A-2) is a linear organopolysiloxane represented by the following formula (2) and having two or more R ¹ (alkenyl groups having 2 to 8 carbon atoms) in one molecule.

(In the formula, R ¹ and R ² are the same as above, R ³ is a group selected from R ¹ or R ² , two or more R ¹ in one molecule, 2 ≤ k1 <20, 0≤k2<10.)

The linear organopolysiloxane having an alkenyl group in the side chain represented by the above formula (2) and optionally having an alkenyl group at the terminal can improve the crosslink density, so that a cured resin product with high hardness can be obtained. In addition, since the addition curing reaction proceeds moderately, it is possible to improve the adhesiveness to the substrate.

In the above formula (2), R ³ is a group selected from the above R ¹ or the above R ² , and 2 or more in one molecule are R ¹ , preferably 10 to 18 are R ¹ . Also, 2≦k1<20 and 0≦k2<10. Said ^R1 is present on the side chain in the molecule, and may be present on either or both ends, preferably on both ends and side chains.

The property of component (A-2) is preferably liquid at 25°C, and the viscosity at 25°C measured by a rotational viscometer according to the method described in JIS K 7117-1: 1999 is 8 to 50 mPa s. A range is more preferred.

（式中、ｋは５～２０の整数である。） Specific examples of the component (A-2) are as follows.

(Wherein, k is an integer from 5 to 20.)

The blending amount of component (A-2) is preferably 1 to 10 parts by mass, more preferably 2 to 8.5 parts by mass, based on 100 parts by mass of component (A-1). More preferably, it is 3 to 8 parts by mass.

<(B) Linear Organohydrogenpolysiloxane>
Component (B) is a linear organohydrogenpolysiloxane represented by the following formula (3).
( ^R4R22SiO1 _/2 ⁾ ₂ ( ^HR2SiO2 _/2 ) _x ( ^R22SiO2 _{/ 2} ) _y (3 ₎
(wherein R ² is the same as above, R ⁴ is a hydrogen atom or a group represented by R ² , x and y are x>0, y>0, and 0.60≦(x / (x + y)) ≤ 0.95 and 30 ≤ x + y ≤ 120.)

The above component (B) acts as a cross-linking agent, and includes alkenyl groups (particularly preferably vinyl groups) bonded to silicon atoms in the above components (A-1) and (A-2), and (B) A cured silicone product is formed from the thermosetting silicone resin composition of the present invention by addition reaction with hydrogen atoms (hydrosilyl groups) bonded to silicon atoms in the component.

The relationship between the content x of HR ² SiO _2/2 units (D units) and the content y of R ² ₂ SiO _2/2 units (D units) in the above formula (3) is 0.60≦(x/ (x+y))≦0.95, preferably 0.70≦(x/(x+y))≦0.90. Further, it is in the range of 30≤x+y≤120, preferably in the range of 40≤x+y≤110.

In the above formula (3), R ² preferably has 1 to 12 carbon atoms, particularly preferably 1 to 10 carbon atoms, specifically, methyl group, ethyl group, propyl group, isopropyl group, butyl group, and isobutyl group. , tert-butyl group, pentyl group, neopentyl group, hexyl group, cyclohexyl group, octyl group, nonyl group, decyl group and the like. Considering the discoloration resistance of the cured silicone product produced from the resulting thermosetting silicone resin composition under high temperature conditions or under blue light with a wavelength of 450 nm for a long period of time, the alkyl group for R ² is selected as the alkyl group for R 2 . , methyl group, ethyl group, propyl group and isopropyl group are preferred, and methyl group is particularly preferred.

In the above formula (3), R ⁴ is a hydrogen atom or a group represented by R ² , and when a group represented by R ² is selected as R ⁴ , a preferred embodiment is a methyl group or an ethyl group as described above. Alkyl groups such as , propyl and isopropyl groups are preferred, and methyl groups are particularly preferred.

Since such linear organohydrogenpolysiloxanes contain abundant siloxane units having silicon-bonded hydrogen atoms on the D units, the curability can be adjusted by steric hindrance during the addition curing reaction. can. In addition, the wettability with the substrate is high, and the remaining hydrosilyl groups that are not incorporated into the addition curing reaction with the alkenyl group due to steric hindrance are converted to hydroxysilyl groups by the addition curing catalyst, improving adhesion with the substrate. can contribute.

The properties of component (B) are preferably liquid at 25°C, and the viscosity at 25°C measured with a rotational viscometer according to the method described in JIS K 7117-1: 1999 is in the range of 30 to 200 mPa s. It is more preferable to have

（式中、ｘ、ｙは上記と同じである。） Specific examples of linear organohydrogenpolysiloxanes for component (B) include the following.

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

In addition, the number of silicon-bonded hydrogen atoms in component (A-1) + component (B) is The total molar number is preferably in the range of 1.0 to 2.0 mol, particularly preferably in the range of 1.1 to 1.5 mol. When the total amount of silicon-bonded hydrogen atoms in components (A-1) and (B) is within the above range, the curing reaction proceeds smoothly, and the adhesion of the silicone to the substrate is high. A cured product can be obtained.

In the thermosetting silicone resin composition of the present invention, R ² of the above components (A-1), (A-2) and (B) is 90 mol % or more, preferably 95 mol %, of all R ² It is preferred that at least mol % be methyl groups. Within this range, the color resistance is excellent when left for a long time under high temperature conditions or under blue light with a wavelength of 450 nm.

<(C) Addition curing catalyst>
The addition curing catalyst of component (C) is added to promote the addition curing reaction of the thermosetting silicone resin composition of the present invention. From the viewpoint of cost and _the like, _platinum , platinum-based _products such as _{chloroplatinic} acid, for example, _{H2PtCl6.mH2O , K2PtCl6} , _KHPtCl6.mH2O , _{K2PtCl4 , K2PtCl4} . Examples include mH ₂ O (m is a positive integer) and the like, and complexes of these with hydrocarbons such as olefins, alcohols, or alkenyl group-containing organopolysiloxanes. can also be used in combination with

The amount of the addition curing catalyst to be added is preferably in the range of 0.1 to 50 ppm, more preferably 1 to 25 ppm, based on the mass unit of the platinum group metal, per 100 parts by mass of the entire thermosetting silicone resin composition. Range. When the amount of the addition curing catalyst is within the above range, the addition curing reaction of the thermosetting silicone resin composition proceeds smoothly, and there is no possibility that the cured silicone product will be colored.

<(D) Adhesion aid>
In addition to the components (A-1) to (C), an adhesion promoter may be added to the thermosetting silicone resin composition of the present invention. The (D) component adhesion aid is blended in order to more preferably exhibit adhesion to the substrate when the thermosetting silicone resin composition of the present invention is cured, and is represented by the following formula (4) It is a branched organopolysiloxane having a weight average molecular weight of 1,500 to 6,000 and an epoxy equivalent of 250 to 500 g/eq.
(MeSiO3 _/2 ) _p1 (EpSiO3 _/2 ) _p2 (EpMeSiO2 _/2 ) _q1 (Me2SiO2 _{/2 ) q2} (ViMeSiO2 _/2 ) _q3 ( ^OR5 ) _r (4)
(In the formula, Me is a methyl group, Ep is a monovalent organic group having an epoxy group, Vi is a vinyl group, R ⁵ is an alkyl group having 1 to 12 carbon atoms, and moles of repeating units For the fractions (content rates) p1 to r, 0≤p1<0.35, 0≤p2<0.35, 0≤q1<0.35, 0.4≤q2<0.7, 0<q3< 0.1, 0≦r<0.05, and 0.15≦(p2+q1)/(p1+p2+q1+q2+q3+r)≦0.35, provided that p1+p2+q1+q2+q3+r=1.)

In the above formula (4), specific examples of the monovalent organic group having an epoxy group represented by Ep include a 3-glycidoxypropyl group, a 2-(3,4-epoxycyclohexyl)ethyl group, 5, Organic groups such as a 6-epoxyhexyl group and a 7,8-epoxyoctyl group can be exemplified. Particularly, Ep is 3-glycidoxypropyl from the viewpoint of storage stability in the state of being blended in the thermosetting silicone resin composition. groups are preferred.

Thus, the branched organopolysiloxane having a large weight-average molecular weight and a small epoxy equivalent has a large polarity difference with the component (A-1), and therefore easily migrates to the interface with the base material during curing. Adhesiveness can be developed. In addition, since it has a vinyl group on the D unit, it is incorporated into the thermosetting silicone resin composition by an addition curing reaction, so it is possible to suppress bleeding out after curing, and a vinyl group on the M unit. Because it is mildly incorporated into the composition compared to those having , it is possible to provide sufficient room for compatibility with the substrate. Furthermore, since it contains a large amount of dimethylsiloxane units, it has good compatibility with the base resin composed of the above components (A-1) to (B), and can be exposed to high temperature conditions or blue light with a wavelength of 450 nm for a long time. Discoloration when left to stand can be suppressed to a low level.

The content p1 of the MeSiO _3/2 units in the formula (4) is in the range of 0≦p1<0.35 with respect to the total p1+p2+q1+q2+q3+r=1 of the siloxane units, and particularly preferably 0≦p1≦ It is in the range of 0.3. The content p2 of EpSiO _3/2 units is in the range of 0≦p2<0.35, particularly preferably 0≦p2≦0.3, with respect to the total of siloxane units p1+p2+q1+q2+q3+r=1. Furthermore, the above-mentioned content q1 of EpMeSiO _2/2 units is in the range of 0≤q1<0.35, particularly preferably in the range of 0≤q1≤0.3 for the total of siloxane units p1+p2+q1+q2+q3+r=1. Furthermore, the above-mentioned content q2 of Me ₂ SiO _2/2 units is 0.4≦q2<0.7, particularly preferably 0.45≦q2≦0.45≦q2≦0.7, with respect to the total of siloxane units p1+p2+q1+q2+q3+r=1. 65 range. Furthermore, the above-mentioned content q3 of ViMeSiO _2/2 units is 0<q3<0.1, particularly preferably in the range 0<q3≦0.08, with respect to the total of siloxane units p1+p2+q1+q2+q3+r=1. Furthermore, the content r of OR ⁵ units is in the range 0≦r<0.05, particularly preferably 0≦r≦0.03, with respect to the total of siloxane units p1+p2+q1+q2+q3+r=1.

In addition, the weight average molecular weight of formula (4) is in the range of 1,500 to 6,000, preferably in the range of 2,000 to 5,000. If the weight-average molecular weight is 6,000 or less, the appearance of the cured silicone resin does not become cloudy.

Furthermore, the epoxy equivalent of formula (4) is in the range of 250 to 500 g/eq, preferably in the range of 300 to 450 g/eq. If the epoxy equivalent is 500 g/eq or less, sufficient adhesiveness to the substrate can be obtained, and if the epoxy equivalent is 250 g/eq or more, the appearance of the cured silicone resin will not become cloudy.

The above component (D) can be easily synthesized by mixing each unit source compound at a content ratio within the above range and performing cohydrolytic condensation, for example, in the presence of a base.

Here, as the EpSiO _3/2 unit source _and the EpMeSiO _2/2 unit source _, organosilicon compounds represented by the following structural formulas can be exemplified. are not limited to these.

The amount of component (D) to be blended is preferably in the range of 0.5 to 10 parts by mass, particularly preferably in the range of 1 to 8 parts by mass, per 100 parts by mass of the entire thermosetting silicone resin composition. . When the amount of component (D) is 0.5 parts by mass or more, the adhesiveness to the substrate is excellent. It is preferable because it becomes transparent.

<Other ingredients>
In addition to the components (A) to (D) described above, the thermosetting silicone resin composition of the present invention may optionally contain various known additives according to the purpose. can.

<Inorganic filler>
The thermosetting silicone resin composition of the present invention is appropriately blended with an inorganic filler for the purpose of improving the strength of the resulting cured product, or for the purpose of imparting thixotropic properties and improving the coating workability of the die attach material. be able to. Examples of inorganic fillers include fumed silica and fumed titanium dioxide. In particular, it is preferable to use fumed silica as the inorganic filler from the viewpoint of the transparency of the resulting cured product.

When blending an inorganic filler, the blending amount is preferably 20 parts by mass or less, more preferably in the range of 1 to 10 parts by mass, per 100 parts by mass of the entire silicone resin composition. In particular, when fumed silica is used as the inorganic filler, the surface of the silica is preferably treated with a hydrophobic group from the viewpoint of compatibility with the silicone resin. Specific examples of hydrophobic groups include siloxane groups such as trimethylsilyl groups and dimethylsilyl groups.

In addition, the surface treatment has the effect of suppressing the interaction between the epoxy groups contained in the component (D) and the hydroxysilyl groups on the surface of the fumed silica, thereby improving the storage stability. Therefore, the fumed silica is preferably sufficiently surface-treated. Specifically, the specific surface area is 150 m ² /g or more and 290 m ² /g or less, preferably 170 m ² /g or more and 230 m ² /g. It is preferred to use fumed silica that is: As the fumed silica surface-treated with a siloxane-based functional group, commercially available products are R812 (specific surface area: 230 to 290 m ² /g) and RX300 (specific surface area: 180 to 220 m ² /g), R976 (specific surface area: 225 to 275 m ² /g) and R976S (specific surface area: 215 to 265 m ² /g) surface-treated with dimethylsilyl groups.

<Curing inhibitor>
The thermosetting silicone resin composition of the present invention may contain a curing inhibitor for the purpose of adjusting the curing speed. Curing inhibitors include, for example, vinyl group-containing organopolysiloxanes such as tetramethyltetravinylcyclotetrasiloxane, hexavinyldisiloxane, 1,3-divinyltetramethyldisiloxane, ethynylcyclohexanol and 3-methyl-1-butyne. A compound selected from the group consisting of acetylene alcohols such as -3-ol, silane-modified and siloxane-modified products thereof, hydroperoxide, tetramethylethylenediamine, benzotriazole, triallyl isocyanurate, alkyl maleate and mixtures thereof, etc. is mentioned. When a curing inhibitor is added, it is preferably added in an amount of 0.001 to 1.0 parts by mass, particularly preferably 0.005 to 0.5 parts by mass, per 100 parts by mass of the silicone resin composition. .

<Heat resistance improver>
The thermosetting silicone resin composition of the present invention may contain a heat resistance improver for the purpose of improving crack resistance in high temperature environments. The heat resistance improver has the effect of suppressing an increase in resin hardness by, for example, severing the dimethylsiloxane chain length against the oxidative deterioration of the silicone resin that progresses in a high temperature environment such as 180° C. or higher. Examples of heat resistance improvers include tris(2-ethylhexanoic acid) cerium(III), trialkoxycerium(III), and siloxane-modified cerium(III).

The amount of the heat resistance improver to be blended is preferably in the range of 0.1 to 100 ppm, more preferably 1 to 50 ppm in mass units of the metal element, per 100 parts by mass of the entire thermosetting silicone resin composition. Range. When the amount of the heat resistance improver is within the above range, the crack resistance in a high-temperature environment is improved, and the decrease in light transmittance due to coloring of the cured silicone resin is reduced. Also, when the die attach material is applied by stamping, it is placed on the resin plate in a thin film state, so it is preferable to use a heat resistance improver with low hydrolyzability.

Depending on the application, the thermosetting silicone resin composition of the present invention can be cured after being applied to a substrate, preferably at a temperature of 100 to 200°C, more preferably at a temperature of 150 to 170°C. Curing can take place. When the heating temperature is within the above range, the adhesive strength between the substrate and the cured resin is improved, air bubbles are not generated due to rapid volatilization of the solvent, and deterioration of the resin is not likely to progress, which is preferable. The heat curing time may be 1 to 4 hours, and a step curing method may be employed.

The thermosetting silicone resin composition of the present invention uses a specific combination of the above-mentioned specific organopolysiloxanes, so that the thermosetting silicone resin composition has higher hardness and resin strength than ordinary thermosetting silicone resin compositions. Moreover, since it has excellent adhesion to the substrate, it can exhibit high adhesive strength even in small-sized chips. A cured resin product with higher hardness and resin strength can be obtained, and the adhesiveness to the substrate is excellent, compared with the silicone resin composition. Therefore, it can be suitably used for electric and electronic parts, and specifically, it can be suitably used as a die attach material for optical semiconductor devices.

EXAMPLES The present invention will be specifically described below by showing examples and comparative examples, but the present invention is not limited to the following examples. Here, "parts" means "mass parts", Me means "methyl group", Vi means "vinyl group", and Ep' means "γ-glycidoxypropyl group". Also, the weight average molecular weight refers to the weight average molecular weight by GPC measurement under the conditions described above. Further, in the following examples, the amount of SiH groups means the number of moles of hydrogen atoms directly bonded to silicon atoms in the molecule ^. DMSO) as an internal standard, and the amount of SiVi groups indicates the number of moles of vinyl groups directly linked to silicon atoms in the molecule, and is measured by ¹ H-NMR using a Bruker nuclear magnetic resonance (NMR) measurement device. It is a value quantified by measurement using DMSO as an internal standard.

<(A-1) Component>
(a1-1): The siloxane units are represented by 9 mol% of ViMe ₂ SiO _1/2 units, 14 mol% of HMe ₂ SiO _1/2 units, and 77 mol% of MeSiO _3/2 units. is 0.18 mol/100 g, the SiVi group weight is 0.11 mol/100 g, the weight average molecular weight is 7,000, and the organopolysiloxane is liquid at 25 ° C.

(a1-2): The siloxane units are represented by 5 mol% of ViMe ₂ SiO _1/2 units, 12 mol% of HMe ₂ SiO _1/2 units, and 83 mol% of MeSiO _3/2 units. is 0.16 mol/100 g, the SiVi group weight is 0.11 mol/100 g, the weight average molecular weight is 8,200, and the organopolysiloxane is liquid at 25 ° C.

(a1-3): The siloxane units consist of 3 mol % of Vi ₃ SiO _1/2 units, 6 mol % of Me ₃ SiO _1/2 units, 14 mol % of HMe ₂ SiO _1/2 units, and MeSiO _3/2 The unit is represented by 77 mol%, the SiH group amount is 0.18 mol / 100 g, the SiVi group amount is 0.11 mol / 100 g, the weight average molecular weight is 6,700, and the liquid organopoly at 25 ° C. Siloxane

(a1-4): The siloxane units consist of 8 mol% of ViMe ₂ SiO _1/2 units, 13 mol% of HMe ₂ SiO _1/2 units, 13 mol% of Me ₃ SiO _1/2 units, and MeSiO _3/2. The unit is represented by 66 mol%, the SiH group amount is 0.18 mol / 100 g, the SiVi group amount is 0.10 mol / 100 g, the weight average molecular weight is 2,800, and the liquid organopoly at 25 ° C. Siloxane (comparative example, c in formula (1) is out of range)

(a1-5): The siloxane units are 12 mol % of ViMe ₂ SiO _1/2 units, 21 mol % of HMe ₂ SiO _1/2 units, 17 mol % of Me ₃ O _1/2 units, and SiO _4/2 The unit is represented by 50 mol%, the SiH group amount is 0.17 mol/100 g, the SiVi group amount is 0.11 mol/100 g, the weight average molecular weight is 4,800, and the organopoly is liquid at 25 ° C. Siloxane (comparative example, b in formula (1) is out of range)

(a1-6): The siloxane units are represented by 11 mol% of ViMe ₂ SiO _1/2 units, 20 mol% of Me ₃ SiO _1/2 units, and 69 mol% of MeSiO _3/2 units. is 0.15 mol / 100 g, the weight average molecular weight is 4,200, and the liquid organopolysiloxane at 25 ° C. (comparative example, b = 0 in formula (1))

(a1-7): the siloxane units are represented by 43 mol% of HMe ₂ SiO _1/2 units and 57 mol% of MeSiO _3/2 units, the amount of SiH groups is 0.63 mol/100 g, and the weight average molecular weight is is 1,800 and liquid organopolysiloxane at 25 ° C. (comparative example, a = 0 in formula (1))

(a1-8): The siloxane units are represented by 10 mol% of ViMe ₂ SiO _1/2 units, 40 mol% of Me ₃ SiO _1/2 units, and 50 mol% of SiO _4/2 units, and the amount of SiVi groups is 0.08 mol / 100 g, the weight average molecular weight is 5,600 by GPC measurement, and the organopolysiloxane is solid at 25 ° C. (comparative example, b = e = 0 in formula (1))

(a1-9): the siloxane units are represented by 7 mol% of Vi ₃ SiO _1/2 units, 41 mol% of Me ₃ SiO _1/2 units, and 52 mol% of SiO _4/2 units; is 0.22 mol/100 g, the weight average molecular weight is 5,800, and the organopolysiloxane is solid at 25° C. (comparative example, b=e=0 in formula (1))

(a1-10): The siloxane units are represented by 25 mol% of HMe ₂ SiO _1/2 units, 25 mol% of Me ₃ SiO _1/2 units, and 50 mol% of SiO _4/2 units, and the amount of SiH groups is 0.40 mol / 100 g, the weight average molecular weight is 2,600, and the liquid organopolysiloxane at 25 ° C. (comparative example, a = e = 0 in formula (1))

<(A-2) Component>
(a2-1): the following formula (ViMe ₂ SiO _1/2 ) ₂ (ViMeSiO _2/2 ) ₈
having a SiVi group weight of 1.16 mol/100 g, a viscosity at 25° C. of 12 mPa s, and a liquid organopolysiloxane (a2-2) at 25° C.: the following formula (ViMe ₂ SiO _1/2 ) ₂ (ViMeSiO _2/2 ) ₁₆
having a SiVi group weight of 1.16 mol/100 g, a viscosity at 25° C. of 22 mPa s, and a liquid organopolysiloxane (a2-3) at 25° C.: the following formula (ViMe ₂ SiO _1/2 ) ₂ (Me ₂ SiO _2/2 ) ₅₀
and has a SiVi group weight of 0.05 mol/100 g, a viscosity at 25 ° C. of 55 mPa s, and a liquid organopolysiloxane at 25 ° C. (comparative example, k2 in formula (2) is out of range)

<Cyclic Organopolysiloxane>
(a3-1): 2,4,6,8-tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane shown below (comparative example)

<(B) Component>
(b-1): the following formula (Me ₃ SiO _1/2 ) ₂ (HMeSiO _2/2 ) ₈₆ (Me ₂ SiO _2/2 ) ₁₀
Organohydrogenpolysiloxane (b-2) represented by the following formula (Me ₃ SiO _1/2 ) ₂ (HMeSiO _2/2 ) ₇₂ (Me ₂ SiO _2/2 ) ₂₄
Organohydrogenpolysiloxane (b-3) represented by the following formula (Me ₃ SiO _1/2 ) ₂ (HMeSiO _2/2 ) ₃₈
Organohydrogenpolysiloxane (comparative example, y = 0 in formula (3) )

<(C) Component>
(c-1): Tetramethyltetravinylcyclotetrasiloxane of a tetramethyltetravinylcyclotetrasiloxane complex of platinum (0) having a platinum content of 2% by mass and an SiVi group amount of 1.15 mol/100 g solution

<(D) Component>
(d-1): The siloxane units are 29 mol% of Ep'SiO _3/2 units, 64 mol% of Me ₂ SiO _2/2 units, 6 mol% of ViMeSiO _2/2 units, and 1 mol% of OMe units. has a weight average molecular weight of 2,400, a SiVi group weight of 0.05 mol/100 g, an epoxy equivalent of 330 g/eq, a liquid at 25 ° C., and a viscosity of 350 mPa s at 25 ° C. Organopolysiloxane (d-2): the siloxane units are 20 mol% MeSiO _3/2 units, 9 mol% Ep'MeSiO _2/2 units, 65 mol% Me ₂ SiO _2/2 units, ViMeSiO _2/2 unit is 5 mol%, OMe unit is 1 mol%, weight average molecular weight is 1,900, SiVi group weight is 0.05 mol/100 g, epoxy equivalent is 850 g/eq, Organopolysiloxane that is liquid at 25°C and has a viscosity of 105 mPa·s at 25°C

<Inorganic filler>
(e-1): Fumed silica "RX300" manufactured by Nippon Aerosil Co., Ltd.

[Examples 1 to 5, Comparative Examples 1 to 6]
The thermosetting silicone resin compositions of Examples 1 to 5 and Comparative Examples 1 to 6 were prepared according to the compounding ratios shown in Table 1 (numbers are parts by mass), and the hardness, bending strength, and adhesiveness of the compositions were evaluated. was evaluated by the test method shown below. Each measurement result is shown in Table 1.

(a) Hardness A cured silicone product was prepared by heating the thermosetting silicone resin composition at 150° C. for 3 hours using a hot air circulating dryer. The cured silicone product was measured using a type D durometer in accordance with JIS K 6253-3:2012.

(b) Bending strength A rod-shaped cured silicone material was produced by heating the thermosetting silicone resin composition at 150°C for 3 hours using a hot air circulation dryer. The silicone cured product was measured according to JIS K 7171:2016.

(c) Adhesion A predetermined amount of a thermosetting silicone resin composition is applied to the center of each cavity of an SMD type 3030 package, which has a silver-plated lead frame, an EMC reflector member, and is cleaned by chemical etching after molding. Then, a small-sized LED chip (manufactured by GeneLite: B1012 (250 μm×300 μm)) was die-bonded, and then cured by heating at 150° C. for 3 hours using a hot air circulating dryer. After heating, the removed package is cooled to 25° C., and the adhesive strength between the LED chip and the silver plating is measured with a bond tester (manufactured by Nordson Advanced Technologies, Inc.: Dage 4000) with 50 tests for each cured resin, Average bond strength was calculated. After the measurement, the silver-plated surface was observed under a microscope to evaluate resin residue. When the area ratio of the average residual resin to the silver-plated side was 70% or more, it was evaluated as "good (○)", and when it was less than 70%, it was evaluated as "improper (x)".

As a result of the above evaluation test, the thermosetting silicone resin composition of the present invention (Examples 1 to 5) has high hardness and resin strength of the cured product, and also has good adhesiveness. It was found to be excellent in adhesive strength. On the other hand, Comparative Example 1, which did not contain component (A-2), and Comparative Examples 2 to 6, which contained organopolysiloxanes other than component (A-1) of the present invention, were inferior in adhesive strength. Therefore, it was confirmed that the thermosetting silicone resin composition of the present invention is extremely useful as a die attach material for optical semiconductor devices.

In addition, this invention is not limited to the said embodiment. The above-described embodiment is an example, and any device having substantially the same configuration as the technical idea described in the claims of the present invention and exhibiting the same effect is the present invention. included in the technical scope of

Claims (4)

the following (A-1), (A-2), (B), and (C) components,
(A-1) Formula (1) below
(R ¹ _n R ² _3-n SiO _1/2 ) _a (HR ² ₂ SiO _1/2 ) _b (R ² ₃ SiO _1/2 ) _c (R ² ₂ SiO _2/2 ) _d (R ² SiO _{3 /2} ) _e (1)
(wherein R ¹ is an alkenyl group having 2 to 8 carbon atoms, R ² is independently an alkyl group having 1 to 12 carbon atoms, and 0.01<a<0.15, 0.05<b<0 .2, 0≦c<0.1, 0≦d<0.1, 0.45<e<0.94, provided that a+b+c+d+e=1 and n is an integer from 1 to 3 is.)
Branched organopolysiloxane represented by and having two or more alkenyl groups having 2 to 8 carbon atoms in one molecule and having two or more hydrogen atoms directly bonded to silicon atoms in one molecule : 100 part by mass ,
(A-2) Formula (2) below

(In the formula, R ¹ and R ² are the same as above, R ³ is a group selected from R ¹ or R ² , two or more R ¹ in one molecule, 2 ≤ k1 <20, 0≤k2<10)
Linear organopolysiloxane represented by : 1 to 10 parts by mass per 100 parts by mass of component (A-1) ,
(B) Formula (3) below
( ^R4R22SiO1 _/2 ⁾ ₂ ( ^HR2SiO2 _/2 ) _x ( ^R22SiO2 _{/ 2} ) _y (3 ₎
(wherein R ² is the same as above, R ⁴ is a hydrogen atom or a group represented by R ² , x and y are x>0, y>0, and 0.60≦(x/ (x + y)) ≤ 0.95 and 30 ≤ x + y ≤ 120.)
Linear organohydrogenpolysiloxane represented by: component (A-1) + component (B) with respect to 1 mole of total number of moles of alkenyl groups bonded to silicon atoms in the entire thermosetting silicone resin composition An amount such that the total number of moles of hydrogen atoms bonded to silicon atoms in the amount is 1.0 to 2.0 moles ,
(C) Addition curing catalyst : 0.1 to 50 ppm by mass of platinum group metal per 100 parts by mass of the entire thermosetting silicone resin composition
As an essential component, a thermosetting silicone resin composition. 2. The thermosetting according to claim ^{1, wherein 90 mol % or more of all R 2 in} the components (A-1), (A-2), and (B) are methyl groups. silicone resin composition. Furthermore, (D) the following formula (4) as an adhesion aid
(MeSiO3 _/2 ) _p1 (EpSiO3 _/2 ) _p2 (EpMeSiO2 _/2 ) _q1 (Me2SiO2 _{/2 ) q2} (ViMeSiO2 _/2 ) _q3 ( ^OR5 ) _r (4)
(In the formula, Me is a methyl group, Ep is a monovalent organic group having an epoxy group, Vi is a vinyl group, R ⁵ is an alkyl group having 1 to 12 carbon atoms, and 0≤p1< 0.35, 0≤p2<0.35, 0≤q1<0.35, 0.4≤q2<0.7, 0<q3<0.1, 0≤r<0.05, and 0. 15≦(p2+q1)/(p1+p2+q1+q2+q3+r)≦0.35, provided that p1+p2+q1+q2+q3+r=1.)
A branched organopolysiloxane having a weight average molecular weight of 1,500 to 6,000 and an epoxy equivalent of 250 to 500 g/eq. The thermosetting silicone resin composition according to claim 1 or 2, characterized by: A die attach material for an optical semiconductor device, comprising the thermosetting silicone resin composition according to any one of claims 1 to 3.