Addition-curable silicone resin composition and die-attach material for semiconductor device

Abstract

To provide an addition reaction-curable silicone resin composition little in change of hardness by a heat history after curing, excellent in resin strength, and having both heat conductivity and low elasticity.SOLUTION: An addition reaction-curable silicone resin composition includes: (A) a branched organopolysiloxane represented by a formula (1) (R11R22SiO1 / 2)a(HR22SiO1 / 2)b(R23SiO1 / 2)c(R22SiO2 / 2)d(R2SiO3 / 2)e, and having two or more 2-8C alkenyl groups and two or more SiH groups in one molecule; (B) a linear organopolysiloxane represented by a formula (2) (R1R22SiO1 / 2)2(R22SiO2 / 2)x(R32SiO2 / 2)y; (C) an addition reaction-curing catalyst; and (D) a heat conductive filler, where the heat conductivity of a cured product thereof is 1.0 W / m K or higher, and the storage modulus at -40°C is 150 MPa or lower.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to an addition-curable silicone resin composition and a die attach material for semiconductor device. [Background technology]

[0002] In recent years, addition-curable silicone resins as die-attach materials in the electronic materials field have attracted attention due to their advantages, such as superior reliability in terms of moisture resistance and heat resistance, excellent stress relaxation properties due to their low elasticity, and easy handling, compared to conventional organic polymer resins such as epoxy resins and acrylic resins.

[0003] For semiconductor applications, when mounting MEMS sensors or CMOS image sensors on a substrate, the sensor die attach material must be able to relieve stress over a wide operating temperature range in order to prevent shocks from the substrate from being transmitted to the chip. Methylphenyl silicone resins that are gel-like or rubber-like in their cured state and have a small amount of phenyl groups as substituents have a glass transition temperature of -50°C or lower and show very little change in storage modulus over a wide temperature range, making them suitable as the above-mentioned sensor die attach material.

[0004] On the other hand, in the case of a die attachment material for a sensor, there are cases where the peripheral components are weak against heat, or where warping is likely to occur during the die attachment material curing process due to the package structure, and therefore there is a demand for curing to be completed to a stage where the chip can be held at a lower temperature, and for hardness to change little with thermal history after curing. In the conventional addition-curable silicone resin composition as mentioned in Patent Document 1, when a VMQ resin having a branched vinyl group at the end is used in addition to a linear polyorganosiloxane compound having vinyl groups at both ends as a SiVi source, the obtained rubber-like cured product has excellent resin strength, but compared to a linear polyorganosiloxane compound having vinyl groups at both ends, the reactivity of the vinyl group is low, and the vinyl group in a sterically crowded position remains without reacting in the curing process, and there is a concern that it will gradually react with thermal history after curing, causing a change in hardness.

[0005] Furthermore, silicone resins that contain a large amount of highly volatile low-molecular-weight siloxane compounds with a degree of polymerization of 10 or less are known to cause problems when used as die-attach materials for sensors. In particular, in CMOS image sensors, if low-molecular-weight siloxane compounds volatilized during processes that involve heat history, such as the die-attach material curing process or reflow, adhere to the on-chip lens formed on the top surface of the chip, they can hinder incident light from reaching the color filter during the operation of the completed package, raising the risk of causing malfunctions. For this reason, there is a demand for low content of low-molecular-weight siloxanes with a degree of polymerization of 10 or less in the entire resin. When using the aforementioned VMQ resin and a linear polyorganosiloxane compound having vinyl groups at both ends as the SiVi source for the addition-curable silicone resin as described in Patent Documents 1 and 2, it is possible to give a rubber-like cured product with excellent resin strength by combining a linear polyorganohydrogenpolysiloxane compound having SiH groups on the side chain as the SiH crosslinking agent. However, such linear polyorganohydrogenpolysiloxane compounds having SiH groups on the side chain have a lower degree of polymerization and a larger amount of low molecular weight siloxane compounds compared to the SiVi source, and furthermore are highly thermally decomposable, and therefore are not preferred as die attach materials for sensors.

[0006] Furthermore, if an addition-curable silicone resin composition does not use a VMQ resin having branched vinyl groups at its terminals, but instead combines a linear polyorganosiloxane compound having vinyl groups at both terminals with a linear polyorganohydrogenpolysiloxane compound having SiH groups in its side chains, the resulting gel-like cured product shows little change in hardness due to thermal history after curing, but the resin strength is not high, making it unsuitable for use as a die attach material for sensors.

[0007] Furthermore, in recent years, high thermal conductivity is also required for die attach materials, especially in CMOS image sensors, due to the increase in heat generation caused by the increase in chip size. When thermal conductivity is imparted to die attach materials, it is common to blend thermally conductive fillers into the resin. However, when a VMQ resin having a branched vinyl group at its end is not used, as described above, and a linear polyorganosiloxane compound having vinyl groups at both ends and a linear polyorganohydrogenpolysiloxane compound having SiH groups at its side chains are combined with an addition curing silicone resin to which a thermally conductive filler is blended, the elasticity can be reduced, but the resin strength of the cured product is low. On the other hand, when a VMQ resin having a branched vinyl group at its end is used, a thermally conductive composition with high resin strength of the cured product is obtained, but the elastic modulus of the cured product is high, and there is a concern that the hardness may change due to the thermal history after curing, as in the case where a thermally conductive filler is not blended.

[0008] Thus, when a conventional addition-curable silicone resin composition having high thermal conductivity is used as a die-attach material for semiconductors, there is a problem in that the hardness changes significantly with the thermal history after curing, and also a problem in that it is difficult to achieve both thermal conductivity and low elasticity when the resin strength of the cured product is high. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] JP 2007-063538 A [Patent Document 2] Japanese Patent Application Publication No. 11-243100 Summary of the Invention [Problem to be solved by the invention]

[0010] The present invention has been made in order to solve the above problems, and has an object to provide an addition-curable silicone resin composition that exhibits minimal change in hardness due to thermal history after curing, has excellent resin strength, and achieves both thermal conductivity and low elasticity.

Means for Solving the Problem

[0011] In order to achieve the above object, the present invention provides: (A) The following formula (1) (R 1 1R 2 2SiO 1 / 2 ) a (HR 2 2SiO 1 / 2 ) b (R 2 3SiO 1 / 2 ) c (R 2 2SiO 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, 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 is a number that satisfies.) which is represented by, has two or more alkenyl groups having 2 to 8 carbon atoms in one molecule, and has hydrogen atoms directly bonded to two or more silicon atoms in one molecule, a branched organopolysiloxane (B) The following formula (2) (R 1 R 2 2SiO 1 / 2 )2(R 2 2SiO 2 / 2 ) x (R 3 2SiO 2 / 2 ) y (2) (In the formula, R 1 and R 2 are the same as above respectively, R 3 is independently an aryl group having 6 to 12 carbon atoms, x and y are x > 0, y ≧ 0, 0.85 ≦ (x / (x + y)), and 50 ≦ x + y ≦ 5000 is a number that satisfies.) a linear organopolysiloxane represented by (C) Addition curing catalyst (D) Thermally conductive filler as an essential component, wherein the addition-curable silicone resin composition is cured to produce a cured silicone resin having a thermal conductivity of 1.0 W / m K or more, and a storage modulus at -40°C of 150 MPa or less.

[0012] With such an addition-curable silicone resin composition, it is possible to obtain an addition-curable silicone resin composition that exhibits little change in hardness due to thermal history after curing, and that has excellent resin strength while also achieving both thermal conductivity and low elasticity.

[0013] In the present invention, the thermally conductive filler, which is component (D), is preferably one or more types selected from the group consisting of silver particles and copper core particles whose surfaces are silver-plated.

[0014] With such an addition-curable silicone resin composition, it is possible to obtain an addition-curable silicone resin composition that achieves both higher thermal conductivity and lower elasticity.

[0015] In the present invention, a compound represented by the following formula (3) is further contained as an adhesion aid (E). (MeSiO 3 / 2 ) p1 (EpSiO 3 / 2 ) p2 (EpMeSiO 2 / 2 ) q1 (MeSiO 2 / 2 ) q2 (ViMeSiO 2 / 2 ) q3 (OR 5 ) r (3) (In the formula, Me is a methyl group, Ep is a monovalent organic group having an epoxy group, Vi is a vinyl group, and R 5is an alkyl group having 1 to 12 carbon atoms, 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.) is a branched organopolysiloxane represented by , and it preferably contains an adhesion promoter component having a weight average molecular weight of 1,500 to 8,000 and an epoxy equivalent of 250 to 500 g / eq for the branched organopolysiloxane.)

[0016] With such an addition-curable silicone resin composition, an addition-curable silicone resin cured product excellent in adhesion to various base materials typified by an organic substrate can be obtained.)

[0017] In the present invention, it is preferable that the amount of the low molecular weight siloxane compound having a degree of polymerization of 10 or less in the whole resin composition is 1% by mass or less.)

[0018] With such an addition-curable silicone resin composition, the adhesion of contaminants to peripheral members during curing is small, and defects in the customer process can be suppressed.)

[0019] With such an addition-curable silicone resin composition, the warpage between the base materials after curing can be suppressed to be small.)

[0020] The present invention also provides a die attach material for a semiconductor device comprising the above addition-curable silicone resin composition.)

[0021] With such a die attach material for a semiconductor device, since the change in hardness due to the thermal history after curing is small and the resin strength of the cured product is high, a highly reliable semiconductor device can be provided.)

Effects of the Invention

[0022] According to the addition-curable silicone resin composition of the present invention, when used as a die attach material for semiconductor devices, there is little change in hardness due to the heat history after curing, excellent resin strength, and it is possible to provide an addition-curable silicone resin composition that achieves both high thermal conductivity and low elastic modulus. Therefore, the addition-curable silicone resin composition of the present invention is extremely useful as a die attach material for semiconductor devices.

Embodiments for Carrying Out the Invention

[0023] The present invention relates to the following components (A), (B), (C), and (D), (A) The following formula (1) (R 1 1R 2 2SiO 1 / 2 ) a (HR 2 2SiO 1 / 2 ) b (R 2 3SiO 1 / 2 ) c (R 2 2SiO 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, 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. A branched organopolysiloxane represented by the formula, 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. (B) The following formula (2) (R 1 R 2 2SiO 1 / 2 )2(R 2 2SiO 2 / 2 ) x (R 3 2SiO 2 / 2 ) y (2) (In the formula, R1 and R 2 are the same as above, and R 3 are each independently an aryl group having 6 to 12 carbon atoms, and x and y are numbers such that x>0, y≧0, 0.85≦(x / (x+y)), and 50≦x+y≦5000. A linear organopolysiloxane represented by the formula: (C) Addition curing catalyst (D) Thermally conductive filler as an essential component, wherein the addition-curable silicone resin composition is cured to produce a cured silicone resin having a thermal conductivity of 1.0 W / m K or more, and a storage modulus at -40°C of 150 MPa or less.

[0024] The present invention will be described in detail below, but the present invention is not limited thereto.

[0025] The addition-curable silicone resin composition of the present invention contains the above-mentioned (A) to (D), and may further contain various additives as necessary. Each component will be described below.

[0026] <(A) Branched organopolysiloxane> Component (A) is represented by formula (1) below and is a branched organopolysiloxane having two or more alkenyl groups having 2 to 8 carbon atoms per molecule and two or more hydrogen atoms directly bonded to silicon atoms per molecule. (R 1 1R 2 2SiO 1 / 2 ) a (HR 2 2SiO 1 / 2 ) b (R 2 3SiO 1 / 2 ) c (R 2 2SiO 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, and R 2 is independently an alkyl group having 1 to 12 carbon atoms. For the molar fractions (contents) a to e of the repeating units, 0.01 < a < 0.15, 0.05 < b < 0.2, 0 ≤ c < 0.1, 0 ≤ d < 0.1, and 0.45 < e < 0.94, provided that a + b + c + d + e = 1.)

[0027] In the above formula (1), R 1 is preferably an alkenyl group having 2 to 8 carbon atoms, particularly 2 to 6 carbon atoms. Specifically, examples include vinyl group, allyl group, isopropenyl group, butenyl group, pentenyl group, hexenyl group, cyclohexenyl group, etc., and particularly the vinyl group is preferred.)

[0028] In the above formula (1), R 2 is preferably an alkyl group having 1 to 12 carbon atoms, particularly 1 to 10 carbon atoms. Specifically, examples include alkyl groups such as methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, pentyl group, neopentyl group, hexyl group, cyclohexyl group, octyl group, nonyl group, decyl group, etc. Considering the heat resistance of the silicone resin cured product prepared from the resulting addition-curable silicone resin composition under high-temperature conditions, alkyl groups such as methyl group, ethyl group, propyl group, and isopropyl group are preferred, and particularly the methyl group is preferred.) 2 As the alkyl group of R

[0029] Thus, the organopolysiloxane having an M unit having an alkenyl group and a hydrosilyl group and a T unit as a resin source has a faster addition curing reaction compared with the conventional organopolysiloxane having an M unit having an alkenyl group and using a Q unit as a resin source, and can give a cured product with less change in hardness during high-temperature storage and also a cured product with excellent resin strength.)

[0030] Also, R 1 1R 2 2SiO 1 / 2The above content fraction a of the unit is in the range of 0.01 < a < 0.15, preferably 0.02 ≤ a ≤ 0.14, with respect to the total of the siloxane units a + b + c + d + e = 1. Also, HR 2 2SiO 1 / 2 The above content fraction b of the unit is in the range of 0.05 < b < 0.2, preferably 0.08 ≤ b ≤ 0.18, with respect to the total of the siloxane units a + b + c + d + e = 1. Also, R 2 3SiO 1 / 2 The above content fraction c of the unit is in the range of 0 ≤ c < 0.1, preferably 0 ≤ c ≤ 0.08, with respect to the total of the siloxane units a + b + c + d + e = 1. Also, R 2 2SiO 2 / 2 The above content fraction d of the unit is in the range of 0 ≤ d < 0.1, preferably 0 ≤ d ≤ 0.08, with respect to the total of the siloxane units a + b + c + d + e = 1. Also, R 2 SiO 3 / 2 Regarding the above content fraction e of the unit, it is in the range of 0.45 < e < 0.94, preferably 0.5 ≤ e ≤ 0.9, with respect to the total of the siloxane units a + b + c + d + e = 1.

[0031] The above component (A) can be easily synthesized by mixing the compounds serving as each unit source at the content fractions within the above ranges and performing co-hydrolysis and condensation, for example, in the presence of an acid. On the other hand, when the molar fractions (content fractions) a to e of the repeating units are outside the above ranges, the addition reaction of the addition-curable silicone resin composition proceeds more slowly than conventional ones, and the resulting cured silicone resin has a large change in hardness when left at high temperature and is also inferior in resin strength.

[0032] Here, the above R 1 1R 2 2SiO 1 / 2 Examples of the unit source include organosilicon compounds such as triorganochlorosilane, triorganoalkoxysilane, and hexaorganodisiloxane represented by the following structural formula, but the R 1 1R 2 2SiO 1 / 2 unit source is not limited to these.

[0033] [ka] [ka]

[0034] In addition, the above HR 2 2SiO 1 / 2 The unit source can be exemplified by organosilicon compounds such as tetraorganodisiloxane represented by the following structural formula. 2 2SiO 1 / 2 The unit sources are not limited to these. [ka]

[0035] In addition, the above R 2 3SiO 1 / 2 Examples of unit sources include organosilicon compounds such as hexaorganodisiloxane represented by the following structural formula. 2 3SiO 1 / 2 The unit sources are not limited to these. [ka]

[0036] In addition, the above R 2 2SiO 2 / 2 Examples of the unit source include organosilicon compounds such as diorganodialkoxysilanes represented by the following structural formulas. 2 2SiO 2 / 2 The unit sources are not limited to these. [ka]

[0037] In addition, the above R 2 SiO 3 / 2 Examples of the unit source include organosilicon compounds such as monoorganotrichlorosilane and monoorganotrialkoxysilane represented by the following structural formula. 2 SiO3 / 2 The unit sources are not limited to these. [ka]

[0038] The state of the component (A) is not particularly limited, but it is preferably liquid at 25°C.

[0039] The weight average molecular weight of the component (A) is preferably in the range of 4,000 to 14,000, and more preferably in the range of 6,000 to 12,000. 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.

[0040] [Measurement conditions] Developing solvent: Tetrahydrofuran (THF) ·Flow rate: 0.6mL / min Detector: Refractive index detector (RI) Column: TSK Guardcolumn SuperH-L ·TSKgel SuperH4000(6.0mmI.D.×15cm×1) ·TSKgel SuperH3000(6.0mmI.D.×15cm×1) ·TSKgel SuperH2000(6.0mmI.D.×15cm×2) (All manufactured by Tosoh Corporation) Column temperature: 40℃ Sample injection volume: 20 μL (0.5% by mass in THF solution)

[0041] <(B) Linear organopolysiloxane> The component (B) is represented by the following formula (2), and has two R 1 It is a linear organopolysiloxane having (an alkenyl group having 2 to 8 carbon atoms). The following formula (2) (R 1 R 2 2SiO1 / 2 )2(R 2 2SiO 2 / 2 ) x (R 3 2SiO 2 / 2 ) y (2) (In the formula, R 1 and R 2 are the same as above, and R 3 are each independently an aryl group having 6 to 12 carbon atoms, and x and y are numbers such that x>0, y≧0, 0.85≦(x / (x+y)), and 50≦x+y≦5000.

[0042] In the above formula (2), R 1 Specific examples of the alkenyl group having 2 to 8 carbon atoms, particularly preferably 2 to 6 carbon atoms, include a vinyl group, an allyl group, an isopropenyl group, a butenyl group, a pentenyl group, a hexenyl group, and a cyclohexenyl group, with a vinyl group being particularly preferred.

[0043] In the above formula (2), R 2 Specific examples of the alkyl group having 1 to 12 carbon atoms, particularly preferably 1 to 10 carbon atoms, include alkyl groups such as methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, pentyl group, neopentyl group, hexyl group, cyclohexyl group, octyl group, nonyl group, and decyl group. 2 As the alkyl group, taking into consideration the heat resistance under high temperature conditions of the cured silicone resin product produced from the resulting addition-curable silicone resin composition, alkyl groups such as methyl, ethyl, propyl and isopropyl groups are preferred, and methyl groups are particularly preferred.

[0044] In the above formula (2), R 3 Specific examples of the aryl group having 6 to 12 carbon atoms include a phenyl group and a naphthyl group, and a phenyl group is particularly preferred. When using a linear organopolysiloxane having a specific amount of phenyl groups introduced in this way, the storage modulus in the low temperature range of the obtained addition-curable silicone resin cured product can be kept low.

[0045] In the above formula (2), x and y are x>0, y≧0, and preferably y>0. In the formula, it is also preferable that x / (x+y) is a number that satisfies 0.85≦x+y≦5000, and more preferably 100≦x+y≦4000. If it is within the above range, it provides an addition-curable silicone resin cured product that has good compatibility with component (A) and high resin strength.

[0046] Regarding the properties of the component (B), it is preferably in a liquid state at 25° C., and more preferably has a viscosity at 25° C. in the range of 8 to 30,000 mPa·s, as measured with a rotational viscometer according to the method described in JIS K 7117-1:1999.

[0047] Specific examples of the component (B) include the following: [ka]

[0048] The blending amount of the component (B) is preferably 100 to 1000 parts by mass, more preferably 150 to 950 parts by mass, and even more preferably 200 to 900 parts by mass, per 100 parts by mass of the component (A).

[0049] <(C) Addition curing catalyst> The addition curing catalyst of component (C) is blended to promote the addition curing reaction of the addition curable silicone resin composition of the present invention, and is available in platinum, palladium, and rhodium types. From the viewpoint of cost, etc., platinum-based catalysts such as platinum and chloroplatinic acid, for example, HPtCl6·mH2O, K2PtCl6, KHPtCl6·mH2O, K2PtCl4, K2PtCl4·mH2O (m is a positive integer), and complexes of these with hydrocarbons such as olefins, alcohols, or alkenyl group-containing organopolysiloxanes can be exemplified, and these can be used alone or in combination of two or more. In addition, in the case of platinum-based catalysts, complexes in which the ligand is removed by ultraviolet light and activity is expressed can be used.

[0050] The amount of the addition curing catalyst is preferably in the range of 0.1 to 300 ppm, more preferably 1 to 100 ppm, in platinum group metal mass units, per 100 parts by mass of the total addition curable silicone resin composition. If the amount of the addition curing catalyst is within the above range, the addition curing reaction of the addition curable silicone resin composition proceeds smoothly, and there is no risk of coloration of the silicone resin cured product.

[0051] <(D) Thermally conductive filler> The thermally conductive filler of component (D) is blended to improve the thermal conductivity of the addition curable silicone resin composition of the present invention, and refers to, for example, a filler having a thermal conductivity of 20 W / m·K or more. The thermally conductive filler may be made of inorganic materials such as metal oxides, such as aluminum oxide and magnesium oxide, metal nitrides, such as silicon nitride and aluminum nitride, and metal carbides, such as silicon carbide, metals, such as silver and aluminum, or metal core particles, such as aluminum and copper, whose surfaces are plated with silver or gold. The shape of the thermally conductive filler may be spherical, elliptical, crushed, or flaky. It is more preferable to use one or more types selected from silver particles and copper core particles whose surfaces are plated with silver, because the storage modulus of the cured product provided by the addition curable silicone resin composition can be kept low and the thermal conductivity is high.

[0052] The particle size of the thermally conductive filler can be selected depending on the film thickness when mounted for the intended purpose. When used as a die attach material for semiconductor device, the average particle size (D50) is preferably 0.1 to 10 μm, more preferably 0.2 to 8 μm. In this specification, the average particle size (D50) is a 50% cumulative value calculated from the particle size distribution obtained on a volume basis by a laser diffraction particle size distribution measuring device.

[0053] The compounding amount of the thermal conductivity filler is preferably in the range of 65 to 90% by mass, more preferably in the range of 70 to 85% by mass, based on the whole addition-curable silicone resin composition. If the compounding amount of the thermal conductivity filler is 90% by mass or less, the storage elastic modulus and the cured product strength of the cured product provided by the addition-curable silicone resin composition will be suitable. If the compounding amount of the thermal conductivity filler is 65% by mass or more, the thermal conductivity of the cured product provided by the addition-curable silicone resin composition will not decrease.

[0054] <(E) Adhesion aid> In the addition-curable silicone resin composition of the present invention, in addition to the components (A) to (D) above, an adhesion aid may be added. The adhesion aid as the component (E) is compounded to more preferably exhibit the adhesiveness with the base material during the curing of the addition-curable silicone resin composition of the present invention, and is a branched organopolysiloxane represented by the following formula (3), having a weight average molecular weight of 1,500 to 8,000 and an epoxy equivalent of 250 to 500 g / eq. (MeSiO 3 / 2 ) p1 (EpSiO 3 / 2 ) p2 (EpMeSiO 2 / 2 ) q1 (Me2SiO 2 / 2 ) q2 (ViMeSiO 2 / 2 ) q3 (OR 5 ) r (3) (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 for the molar fraction (content) p1 to r of the repeating units, 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.)

[0055] In the above formula (3), specific examples of the monovalent organic group having an epoxy group represented by Ep include organic groups such as a 3-glycidoxypropyl group, a 2-(3,4-epoxycyclohexyl)ethyl group, a 5,6-epoxyhexyl group, and a 7,8-epoxyoctyl group. From the viewpoint of storage stability when incorporated into an addition-curable silicone resin composition, a 3-glycidoxypropyl group is particularly preferred as Ep.

[0056] In this way, the branched organopolysiloxane with a large weight average molecular weight and a small epoxy equivalent has a large polarity difference with component (A), and therefore is easily transferred to the interface with the substrate during curing, and can exhibit good adhesion. In addition, since it has a vinyl group on the D unit, it is incorporated into the addition curable silicone resin composition by the addition curing reaction, so that bleeding out after curing can be suppressed, and furthermore, since it is incorporated into the composition more mildly than those having a vinyl group on the M unit, it can be provided with room for sufficient compatibility with the substrate.

[0057] In addition, MeSiO 3 / 2 The content p1 of the siloxane units is in the range of 0≦p1<0.35, and more preferably in the range of 0≦p1≦0.3, relative to the total amount of the siloxane units p1+p2+q1+q2+q3+r=1. 3 / 2 The content p2 of the units is in the range of 0≦p2<0.35, particularly preferably 0≦p2≦0.3, relative to the total number of siloxane units p1+p2+q1+q2+q3+r=1. 2 / 2 The content q1 of the unit is in the range of 0≦q1<0.35, particularly preferably in the range of 0≦q1≦0.3, relative to the total of the siloxane units p1+p2+q1+q2+q3+r=1. 2 / 2 The content q2 of the unit is 0.4≦q2<0.7, particularly preferably 0.45≦q2≦0.65, relative to the total of the siloxane units p1+p2+q1+q2+q3+r=1. 2 / 2The above content fraction q3 of the unit satisfies 0 < q3 < 0.1 with respect to the total of the siloxane units p1 + p2 + q1 + q2 + q3 + r = 1, and particularly preferably, it is in the range of 0 < q3 ≤ 0.08. Further, OR 5 The above content fraction r of the unit satisfies 0 ≤ r < 0.05 with respect to the total of the siloxane units p1 + p2 + q1 + q2 + q3 + r = 1, and particularly preferably, it is in the range of 0 ≤ r ≤ 0.03.

[0058] Also, the weight average molecular weight of the above formula (3) is in the range of 1,500 to 8,000, and preferably in the range of 2,000 to 7,500. If the weight average molecular weight is 8,000 or less, the appearance of the silicone resin cured product will not become cloudy, and if the weight average molecular weight is 1,500 or more, sufficient adhesiveness to the substrate can be obtained.

[0059] Furthermore, the epoxy equivalent of the above formula (3) is in the range of 250 to 500 g / eq, and 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 silicone resin cured product will not become cloudy.

[0060] The above component (E) can be easily synthesized by mixing the compounds serving as each unit source at the content fractions within the above ranges and performing co-hydrolysis condensation, for example, in the presence of a base.

[0061] Here, the above EpSiO 3 / 2 unit source and EpMeSiO 2 / 2 As the unit source, organosilicon compounds represented by the following structural formulas can be exemplified, but the usable EpSiO 3 / 2 unit source and EpMeSiO 2 / 2 unit source are not limited to these.

[0062]

Chemical formula

[0063]

Chemical formula

[0064] The amount of component (E) is preferably in the range of 0.5 to 10 parts by mass, and particularly preferably 1 to 5 parts by mass, per 100 parts by mass of the total addition-curable silicone resin composition. If the amount of component (E) is 0.5 parts by mass or more, excellent adhesion to the substrate is achieved, and if it is 10 parts by mass or less, it can be used without problems in coating workability, and this is preferred.

[0065] <Inorganic filler> In the addition curable silicone resin composition of the present invention, an inorganic filler other than component (D) can be appropriately blended for the purpose of improving the strength of the obtained cured product or for the purpose of imparting thixotropy and improving the application workability of the die attachment material. Examples of inorganic fillers include fumed silica and quartz powder. In particular, from the viewpoint of the transparency of the obtained cured product, it is preferable to use fumed silica as the inorganic filler.

[0066] When an inorganic filler is blended, the blending amount is preferably 10 parts by mass or less, more preferably 1 to 5 parts by mass, based on 100 parts by mass of the entire silicone resin composition. In particular, when fumed silica is used as the inorganic filler, it is preferable that the silica surface is treated with a hydrophobic group from the viewpoint of compatibility with the silicone resin. Specific examples of the hydrophobic group include siloxanes such as trimethylsilyl and dimethylsilyl groups.

[0067] In addition, the surface treatment also has the effect of suppressing the interaction between the epoxy groups contained in the (E) component and the hydroxysilyl groups on the surface of the fumed silica, thereby improving storage stability. For this reason, it is preferable for the fumed silica to be one that has been sufficiently surface-treated. Specifically, it is preferable for the fumed silica to be one that has a specific surface area of ​​150 m 2 / g or more 290m 2 / g or less, preferably 170m 2 / g or more 230m 2It is preferable to use fumed silica having a specific surface area of ​​230 to 290 m2 or less. As the fumed silica surface-treated with a siloxane-based functional group, a commercially available product is R812 (specific surface area: 230 to 290 m2) surface-treated with a trimethylsilyl group by Nippon Aerosil Co., Ltd. 2 / g) and RX300 (specific surface area 180-220 m 2 / g), R976 (specific surface area 225-275 m2) surface-treated with dimethylsilyl groups 2 / g), R976S (specific surface area 215~265m 2 The specific surface area can be determined by the BET method.

[0068] In the addition-curable silicone resin composition of the present invention, the amount of low molecular weight siloxane compounds with a degree of polymerization of 10 or less in the entire resin composition is preferably 1% by mass or less, and more preferably 0.5% by mass or less. If the amount of low molecular weight siloxane compounds with a degree of polymerization of 10 or less is the above amount or less, it is possible to provide a semiconductor package that causes little contamination of surrounding components and does not impair operation.

[0069] The content of low molecular weight siloxane compounds having a degree of polymerization of 10 or less referred to in the present invention refers to the content (by mass) of the low molecular weight siloxane compounds quantified by gas chromatography measured under the following conditions.

[0070] [Measurement conditions] Equipment: GC-2014 (Shimadzu Corporation) Column: Product name: HP-5MS (Agilent Technologies, Inc., inner diameter: 0.25 mm, length: 30 m, packing material: (5%-phenyl)-methylpolysiloxane) Detector: FID detector (detector temperature: 300℃) Sample: 1.0 g of sample was dissolved in 10 mL of n-tetradecane / acetone standard solution (concentration: 20 μg / mL) to prepare a sample. ·Injection volume: 1μL Oven temperature: 50℃-280℃ / 23 minutes-280℃ / 17 minutes Carrier gas: Type…Helium, Linear velocity…34.0cm / s

[0071] The addition-curable silicone resin composition of the present invention must have a thermal conductivity of at least 1.0 W / m K after curing, and preferably at least 1.5 W / m K. If the thermal conductivity of the cured resin after curing is less than 1.0 W / m K, when used as a semiconductor die attach material, it will not be possible to sufficiently dissipate the heat generated by the semiconductor chip, making it impossible to reduce the power consumption of the semiconductor package or to prevent breakdowns.

[0072] Furthermore, the addition-curable silicone resin composition of the present invention must have a storage modulus of 150 MPa or less, and preferably 100 MPa or less, of the cured resin after curing at −40° C. If the storage modulus of the cured resin after curing exceeds 150 MPa at −40° C., the warping of the semiconductor package in the operating temperature range will become significant, resulting in operational failure.

[0073] The addition-curable silicone resin composition of the present invention can be applied onto a substrate and then cured according to the application, and can be heat-cured at a temperature of preferably 70 to 130° C., more preferably 90 to 1200° C. If the heating temperature is within the above range, the adhesive strength between the substrate and the cured resin is improved, and it is possible to provide a semiconductor package with less warping, which is preferable. The heat-curing time may be 0.5 to 2.5 hours, and a step-curing method may be adopted.

[0074] The addition-curable silicone resin composition of the present invention uses the specific organopolysiloxanes in a specific combination, and as a result, compared to ordinary addition-curable silicone resin compositions, it is possible to obtain an addition-curable silicone resin composition that exhibits less change in hardness due to thermal history after curing and has excellent resin strength, and thus can be suitably used for electrical and electronic component applications, specifically as a die attach material for semiconductor devices.

[0075] It is believed that the reason such effects are exhibited is that, by using the above organopolysiloxanes in specific combinations, there is less change in hardness due to thermal history after curing, and the cured product has excellent resin strength, compared to conventional addition-curable silicone resin compositions. EXAMPLES

[0076] The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to the following examples. Note that parts refers to "parts by mass", Me represents "methyl group", Vi represents "vinyl group", and Ep' represents "3-glycidoxypropyl group". Furthermore, the weight average molecular weight refers to the weight average molecular weight measured by GPC under the above-mentioned conditions. In the following examples, the amount of SiH groups refers to the number of moles of hydrogen atoms directly bonded to silicon atoms in a molecule, and is measured using a Bruker Nuclear Magnetic Resonance (NMR) measurement device. 1 The value was quantified by H-NMR measurement using dimethyl sulfoxide (DMSO) as an internal standard. The amount of SiVi groups indicates the number of moles of vinyl groups directly bonded to silicon atoms in the molecule, and was measured using a Bruker Nuclear Magnetic Resonance (NMR) measurement device. 1 The values ​​were quantified by H-NMR measurement using DMSO as an internal standard. The average particle size was measured under the conditions described above, and the viscosity was measured at 25°C using a rotational viscometer according to the method described in JIS K 7117-1:1999.

[0077] <Component (A)> (a-1): The siloxane unit is ViMe2SiO 1 / 2 Units: 5 mol%, HMe2SiO 1 / 2 Units: 12 mol%, MeSiO 3 / 2 A branched organopolysiloxane which is liquid at 25°C, has a unit of 83 mol%, a SiH group amount of 0.16 mol / 100 g, a SiVi group amount of 0.11 mol / 100 g, a weight average molecular weight of 8,200, and a content of low molecular weight siloxane compounds having a degree of polymerization of 10 or less of 0.2 mass%. (a-2): The siloxane unit is ViMe2SiO 1 / 2 Units: 10 mol%, Me3SiO1 / 2 The unit is 40 mol%, SiO 4 / 2 The unit is shown as 50 mol%, the SiVi group content is 0.08 mol / 100 g, the weight-average molecular weight by GPC measurement is 5,600, the content of low-molecular siloxane compounds with a degree of polymerization of 10 or less is 0.1% by mass, and it is a branched organopolysiloxane that is solid at 25 °C (for comparison)

[0078] <(Component (B))> (b-1): The following formula (ViMe2SiO 1 / 2 )2(Ph2SiO 2 / 2 ) 20 (Me2SiO 2 / 2 ) 350 It is represented by, the SiVi group content is 0.006 mol / 100 g, it is liquid at 25 °C, the content of low-molecular siloxane compounds with a degree of polymerization of 10 or less is 0.1% by mass, and it is a linear organopolysiloxane with a viscosity of 5,100 mPa·s at 25 °C

[0079] <SiH crosslinking agent> (f-1): The following formula (Me3SiO 1 / 2 )2(HMeSiO 2 / 2 ) 72 (Me2SiO 2 / 2 ) 24 It is represented by, the hydrosilyl group content is 1.14 mol / 100 g, it is liquid at 25 °C, the content of low-molecular siloxane compounds with a degree of polymerization of 10 or less is 0.1% by mass, and it is an organohydrogenpolysiloxane with a viscosity of 163 mPa·s at 25 °C

[0080] <(Component (C))> (c-1): A solution of a platinum(0) 1,3-divinyltetramethyldisiloxane complex in 1,3-divinyltetramethyldisiloxane with a platinum content of 2% by mass and a SiVi group content of 1.05 mol / 100 g

[0081] <(Component (D))> (d-1): Flake-shaped silver powder "AgC-237" with an average particle size (D50) of 6.5 μm (manufactured by Fukuda Metal Foil Industry Co., Ltd.) (d-2): Spherical silver-plated copper core powder "TFM-C05P" with an average particle size (D50) of 6.1 μm (manufactured by Toyo Aluminum Co., Ltd.)

[0082] <(E) component> (e-1): The siloxane unit is Ep'SiO 3 / 2 Units: 29 mol%, Me2SiO 2 / 2 The unit is 64 mol%, ViMeSiO 2 / 2 A branched organopolysiloxane having 6 mol% OMe units and 1 mol% OMe units, a weight average molecular weight of 2,400, an amount of SiVi groups of 0.05 mol / 100 g, an epoxy equivalent of 330 g / eq, being liquid at 25°C, containing 0.3 mass% low molecular weight siloxane compounds having a degree of polymerization of 10 or less, and having a viscosity of 350 mPa s at 25°C. (e-2): The siloxane unit is MeSiO 3 / 2 25 mol% of the unit Ep'MeSiO 2 / 2 Units: 22 mol%, Me2SiO 2 / 2 The unit is 47 mol%, ViMeSiO 2 / 2 A branched organopolysiloxane having 5 mol % OMe units and 1 mol % OMe units, a weight average molecular weight of 4,500, an amount of SiVi groups of 0.05 mol / 100 g, an epoxy equivalent of 435 g / eq, being liquid at 25°C, containing 0.1 mass % low molecular weight siloxane compounds having a degree of polymerization of 10 or less, and having a viscosity of 355 mPa s at 25°C.

[0083] [Examples 1 to 4, Comparative Examples 1 to 3] The addition-curable silicone resin compositions of Examples 1 to 4 and Comparative Examples 1 to 3 were prepared according to the compounding ratios (values ​​are parts by mass) shown in Table 1, and the initial hardness of the cured products of the compositions, hardness after standing at 150°C for 1000 hours, tensile strength, elongation at break, storage modulus of the cured products at -40°C, adhesion, thermal conductivity, and content of low molecular weight siloxane compounds with a degree of polymerization of 10 or less were evaluated using the test methods shown below. The results of each measurement are shown in Table 1.

[0084] (a) Initial hardness The addition-curable silicone resin composition was heated at 100° C. for 1 hour using a hot air circulation dryer to produce a silicone resin cured product. The silicone resin cured product was measured using a type A durometer in accordance with JIS K 6253-3:2012.

[0085] (b) Hardness after 150℃ x 1000 hours The silicone resin cured product obtained in (a) above was heated in a hot air circulation dryer at 150°C for 1000 hours. After that, it was measured using a Type A durometer in accordance with JIS K 6253-3:2012, and the hardness was compared with the initial hardness.

[0086] (c) Tensile strength, elongation at break The addition-curable silicone resin composition was heated in a hot air circulating dryer at 100° C. for 1 hour to produce a cured silicone resin. The tensile strength and elongation at break of the cured silicone resin were measured in accordance with JIS K 6250.

[0087] (d) Storage modulus of cured material at -40°C The addition curable silicone resin composition was heated at 100°C for 1 hour using a hot air circulation dryer to produce a 2 mm thick sheet-shaped silicone resin cured product. The storage modulus of the silicone resin cured product at -40°C was measured using a dynamic viscoelasticity measuring device (DMA) "Q800" manufactured by TA Instruments Japan, Inc.

[0088] (e) Adhesiveness A given amount of addition-curable silicone resin composition was applied onto a glass epoxy substrate, FR-4, and a Si chip measuring 3.0 mm x 3.0 mm was die-bonded, followed by heat curing at 100°C for 1 hour using a hot air circulation dryer. After heating, the removed package was cooled to 25°C, and the adhesive strength between the chip and substrate was measured for each cured resin product using a bond tester (Nordson Advanced Technology Corp.: Dage4000) for 50 tests, and the average adhesive strength was calculated.

[0089] (f) Thermal conductivity The addition-curable silicone resin composition was heated at 100° C. for 1 hour using a hot air circulation dryer to produce sheet-shaped cured silicone resin products with thicknesses of 0.5 mm, 1 mm, and 2 mm. The cured material of each thickness was cut into 10 mm squares, and the thermal resistance value for each thickness was obtained using a resin material thermal resistance measuring device (manufactured by Hitachi Technology and Services), which uses the steady-state measurement principle (load: 100 kPa). After plotting the three measurement results, an approximation curve was drawn using linear approximation, and the thermal conductivity of each cured resin was calculated from the slope of the linear approximation curve and the size of the cured material.

[0090] (g) Content of low molecular weight siloxane compounds with a degree of polymerization of 10 or less The content of low molecular weight siloxane compounds having a degree of polymerization of 10 or less in the addition-curable silicone resin composition was measured using the same method as described above.

[0091] [Table 1]

[0092] As a result of the above evaluation test, it was found that the addition curable silicone resin composition of the present invention (Examples 1 to 4) has a small change in hardness due to thermal history after curing, has excellent resin strength, and is compatible with thermal conductivity and low elasticity. On the other hand, Comparative Example 1 has low thermal conductivity because it does not have a thermally conductive filler, and Comparative Example 2 does not contain component (A), so the strength and adhesiveness of the resin cured product are very low. In addition, Comparative Example 3 has a large change in hardness due to thermal history after curing. Therefore, it was confirmed that the addition curable silicone resin composition of the present invention is extremely useful as a die attach material for semiconductor device because it has a small change in hardness due to thermal history after curing, has excellent resin strength, and is compatible with thermal conductivity and low elasticity.

[0093] The present invention is not limited to the above-described embodiment. The above-described embodiment is merely an example, and anything that has substantially the same configuration as the technical idea described in the claims of the present invention and exhibits similar effects is included in the technical scope of the present invention.

Claims

1. (A) Formula (1) below (R １ １ R ２ ２ 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 are independently an alkyl group having 1 to 12 carbon atoms, and are numbers satisfying 0.01<a<0.15, 0.05<b<0.2, 0≦c<0.1, 0≦d<0.1, and 0.45<e<0.94, and a+b+c+d+e=1.) and having two or more alkenyl groups having 2 to 8 carbon atoms in each molecule and having two or more hydrogen atoms directly bonded to silicon atoms in each molecule. (B) The following formula (2) (R １ R ２ ２ SiO １／２ ) ２ (R ２ ２ SiO ２／２ ) ｘ (R ３ ２ SiO ２／２ ) ｙ (2) (In the formula, R １ and R ２ are the same as above, and R ３ are independently an aryl group having 6 to 12 carbon atoms, and x and y are numbers such that x>0, y>0, 0.85≦(x / (x+y)), and 50≦x+y≦5000. A linear organopolysiloxane represented by the formula: (C) Addition curing catalyst (D) Thermally conductive filler as an essential component, wherein the addition-curable silicone resin composition is cured to produce a cured silicone resin having a thermal conductivity of 1.0 W / m K or more, and a storage modulus at -40°C of 150 MPa or less.

2. 2. The addition-curable silicone resin composition according to claim 1, wherein the thermally conductive filler (D) is one or more types selected from the group consisting of silver particles and copper core particles having a silver-plated surface.

3. Furthermore, as an adhesive assistant (E), a compound represented by the following formula (3) (MeSi) ３／２ ) ｐ１ (EpSiO) ３／２ ) ｐ２ (Ep. Me. Si.) ２／２ ) ｑ１ (Me) ２ SiO ２／２ ) ｑ２ (Violet) ２／２ ) ｑ３ (OR) ５ ) ｒ (3) (In the formula, Me is a methyl group, Ep is a monovalent organic group having an epoxy group, Vi is a vinyl group, and R ５ is an alkyl group having 1 to 12 carbon atoms, 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. wherein the branched organopolysiloxane has a weight average molecular weight of 1,500 to 8,000 and an epoxy equivalent of 250 to 500 g / eq.

4. The addition curable silicone resin composition as a whole contains a low molecular weight siloxane compound having a degree of polymerization of 10 or less. The addition-curable silicone resin composition according to claim 1 , wherein the amount of the component (A) is 1% by mass or less.

5. A die attach material for semiconductor device, comprising the addition-curable silicone resin composition according to any one of claims 1 to 4.

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