JP2019173023A - Sheet for semiconductor bonding and semiconductor device including the same - Google Patents

Abstract

To provide a sheet for semiconductor bonding that has excellent thermal conductivity and electric conductivity, and is optimal for joining of a power semiconductor element to an element support member.SOLUTION: A sheet for semiconductor bonding is obtained by using a resin composition for semiconductor bonding that contains (A) a bismaleimide resin having an aliphatic hydrocarbon group in the main chain, (B) a curing agent, (C) a filler containing conductive particles with a specific gravity of 1.1-5.0, and (D) silver fine particles with an average particle size of 10-300 nm. There is also provided a semiconductor device obtained by joining a semiconductor with the sheet for semiconductor bonding.SELECTED DRAWING: None

Description

  The present invention relates to a semiconductor bonding sheet and a semiconductor device, and more particularly to a firing type semiconductor bonding sheet and a semiconductor device that are optimal for bonding a power semiconductor element and a substrate.

  In recent years, due to increasing awareness of environmental problems, power semiconductor devices have been widely used not only for general industrial and electric railway applications but also for in-vehicle applications. Especially for in-vehicle components, reducing the size and weight of each component within a limited allowable size directly affects the performance of the vehicle, so reducing the size of power semiconductor devices is a very important issue. It has become.

In such a semiconductor device, for example, a power semiconductor element is mounted on a die pad of a DBC (Direct Bonded Copper: registered trademark) substrate through a high lead solder having high heat resistance.
However, the use of harmful substances containing lead has been regulated, and lead-free is required.

  Therefore, as a high heat-resistant lead-free bonding material other than high-lead solder, a bonding method using a sintered silver paste for bonding a nano-order silver filler at a temperature below the melting point has been studied. Sintered silver paste has high thermal conductivity and is effective for bonding power semiconductor elements that handle large currents.

  However, high lead pastes and fired silver pastes are one of the factors that hinder size reduction because of the formation of fillets. Therefore, for example, a bonding method of a semiconductor element and a DBC substrate using a porous metallic film (see Patent Document 1) or a film-like silver paste formed by pre-drying a printed silver paste is transferred to a semiconductor element and bonded to a DBC substrate. The method (refer patent document 2) to do is proposed.

US Patent Application Publication No. 2013/0256894 Special table 2014-503936 gazette

  However, in the method of Patent Document 1, there is a high possibility that voids existing in the bonding layer adversely affect thermal conductivity and reliability. In the method of Patent Document 2, the resin composition must be made high viscosity and high thixotropy. Since silver having a large specific gravity will settle, the desired thermal conductivity and electrical conductivity may not be obtained. Furthermore, it is difficult to form a continuous adhesive sheet with such a high viscosity resin composition. There was a problem such as.

  Accordingly, the present invention has been made to solve the above problems, and can exhibit excellent thermal conductivity and conductivity, and is a fired semiconductor adhesive suitable for joining a power semiconductor element and an element support member. The purpose is to provide a sheet for use. Another object of the present invention is to provide a semiconductor device using the semiconductor bonding sheet.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have used in combination a combination of conductive particles that have a specific gravity range of particles to be blended as a filler and silver particles of a specific size. It has been found that good thermal conductivity and electrical conductivity can be expressed by using the resin composition. Furthermore, the present inventors are able to suppress the sedimentation of particles even when such a resin composition is diluted with a solvent such as being applied and dried into a carrier sheet, and further, sintering between the conductive particles. The present invention was completed.

  That is, the semiconductor adhesive sheet of the present invention comprises (A) a bismaleimide resin having an aliphatic hydrocarbon group in the main chain, (B) a curing agent, and (C) a conductive material having a specific gravity of 1.1 to 5.0. A resin composition for semiconductor adhesion containing a filler containing particles and (D) silver fine particles having an average particle diameter of 10 to 300 nm as essential components is formed into a sheet shape.

  The semiconductor device of the present invention is characterized in that a semiconductor element is bonded onto a support member via the semiconductor bonding sheet of the present invention.

  The resin composition for semiconductor bonding used in the present invention is an adhesive material that can exhibit excellent thermal conductivity and conductivity. For example, when the resin is diluted with a solvent when it is formed into a sheet shape, the particle composition is also dried. Sedimentation can be suppressed, and it is particularly suitable for forming a sinterable adhesive sheet.

  The semiconductor bonding sheet of the present invention can exhibit excellent thermal conductivity and conductivity, and is suitable for bonding a semiconductor element on a support member, and particularly optimal for bonding a power semiconductor element on a support member. is there. Furthermore, since the semiconductor bonding sheet does not generate a fillet when a semiconductor element is mounted, it is effective for miniaturization of a semiconductor device.

  In the semiconductor device of the present invention, the semiconductor element has excellent thermal conductivity and conductivity, and is bonded onto the support member, so that the operation can be performed efficiently and stably.

Hereinafter, the present invention will be described in detail.
As described above, the resin composition for semiconductor bonding used in the present invention comprises (A) a bismaleimide resin having an aliphatic hydrocarbon group in the main chain, (B) a curing agent, and (C) a specific gravity of 1.1 to 5 0.0 filler particles containing conductive particles and (D) silver fine particles having an average particle diameter of 10 to 300 nm are essential components. Hereinafter, each component will be described in order.

The component (A) used in the present invention is a bismaleimide resin having an aliphatic hydrocarbon group in the main chain, and the main chain connecting two maleimide groups is an aliphatic hydrocarbon group having 1 or more carbon atoms. It is comprised. Here, the aliphatic hydrocarbon group may be any of linear, branched and cyclic forms, preferably having 6 or more carbon atoms, more preferably 12 or more carbon atoms, It is particularly preferable that the number of carbon atoms is 24 or more. The aliphatic hydrocarbon group is preferably directly bonded to the maleimide group.
By containing such a bismaleimide resin, it is possible to obtain a resin composition for semiconductor adhesion that is excellent in heat resistance and has a low stress and good adhesive strength during heat after moisture absorption.

  As the component (A), an imide-extended bismaleimide compound (A1) represented by the following general formula (1) is preferable.

（式中、ｎは１〜１０の整数である。）
このビスマレイミド化合物（Ａ１）としては、例えば、ＢＭＩ−３０００（デジグナーモレキュールズ社製、商品名；分子量 ３０００）、ＢＭＩ−５０００（デジグナーモレキュールズ社製、商品名；分子量 ５０００）、等が挙げられる。

(In the formula, n is an integer of 1 to 10.)
As this bismaleimide compound (A1), for example, BMI-3000 (manufactured by Designa Molecules, trade name; molecular weight 3000), BMI-5000 (manufactured by Digina Molecules, trade name: molecular weight 5000), Etc.

  The bismaleimide compound (A1) preferably has a number average molecular weight of from 500 to 5,000, more preferably from 1,000 to 3,000, in terms of polystyrene. When the number average molecular weight is less than 500, the heat resistance is lowered, and when it exceeds 5000, the tackiness at the time of manufacturing a semiconductor device tends to be lowered.

  Moreover, as this (A) component, the bismaleimide compound (A2) represented by following General formula (2) is mentioned as a preferable thing.

（式中、Ｑは炭素数６以上の２価の直鎖状、分枝鎖状又は環状の脂肪族炭化水素基を示し、Ｐは２価の原子又は有機基であって、Ｏ、ＣＯ、ＣＯＯ、ＣＨ_２、Ｃ（ＣＨ_３）_２、Ｃ（ＣＦ_３）_２、Ｓ、Ｓ_２、ＳＯ及びＳＯ_２から選ばれる２価の原子又は有機基を少なくとも１つ以上含む基であり、ｍは１〜１０の整数を表す。）が好ましく用いられる。ここで、Ｐで表される２価の原子は、Ｏ、Ｓ等が挙げられ、２価の有機基は、ＣＯ、ＣＯＯ、ＣＨ_２、Ｃ（ＣＨ_３）_２、Ｃ（ＣＦ_３）_２、Ｓ_２、ＳＯ、ＳＯ_２等、また、これらの原子又は有機基を少なくとも１つ以上含む有機基が挙げられる。上記した原子又は有機基を含む有機基としては、上記以外の構造として、炭素数１〜３の炭化水素基、ベンゼン環、シクロ環、ウレタン結合等を有するものが挙げられ、その場合のＰとして次の化学式で表される基が例示できる。

(In the formula, Q represents a divalent linear, branched or cyclic aliphatic hydrocarbon group having 6 or more carbon atoms, P is a divalent atom or organic group, and O, CO, M is a group containing at least one divalent atom or organic group selected from COO, CH ₂ , C (CH ₃ ) ₂ , C (CF ₃ ) ₂ , S, S ₂ , SO and SO _2; Represents an integer of 1 to 10.) is preferably used. Here, examples of the divalent atom represented by P include O and S, and examples of the divalent organic group include CO, COO, CH ₂ , C (CH ₃ ) ₂ , C (CF ₃ ) ₂ , S ₂ , SO, SO _{2 and the} like, and organic groups containing at least one or more of these atoms or organic groups are exemplified. Examples of the organic group including the above-described atom or organic group include those having a hydrocarbon group having 1 to 3 carbon atoms, a benzene ring, a cyclo ring, a urethane bond, etc. as a structure other than the above, and as P in that case Examples include groups represented by the following chemical formula.

このビスマレイミド化合物（Ａ２）としては、ＢＭＩ−１５００（デジグナーモレキュールズ社製、商品名；分子量 １５００）、等が挙げられる。

Examples of the bismaleimide compound (A2) include BMI-1500 (manufactured by Designer Molecules, Inc., trade name: molecular weight 1500), and the like.

This (A) component may be used individually by 1 type, and 2 or more types may be mixed and used for it. As the blending ratio of the component (A) is higher, a resin composition for semiconductor adhesion having a better adhesive strength when heated after moisture absorption is obtained. In addition, it exists in the tendency for what was excellent in followability by mix | blending (A1) component with what was more excellent in sheet forming ability, and (A2) component.
Moreover, when mixing 2 or more types of (A) component, it is preferable to use together the said bismaleimide compound (A1) and a bismaleimide compound (A2). At this time, it is preferable to use the bismaleimide compounds (A1) and (A2) in combination at a ratio of (A1) / (A2) of 5/95 to 30/70 on a mass basis. When the above ratio (A1) is 5 or more, the sheet formability is improved, and when it is 30 or less, the tackability is good. That is, when (A1) / (A2) is in the above range, a resin composition for semiconductor adhesion that is easy to form a sheet and has good tackability is obtained.

  The (B) curing agent used in the present invention is not particularly limited as long as it is a polymerization catalyst generally used for radical polymerization, but is preferably a peroxide. Further, as the peroxide, an organic peroxide is more preferable, and a peroxide that generates a radical upon heating at 120 ° C. or lower is preferable.

Examples of the organic peroxide of the component (B) include t-butylperoxy-2-ethylhexanoate, benzoyl peroxide, t-butyl peroxide, acetyl peroxide, methyl ethyl ketone peroxide, acyl peroxide, Cumene peroxide and the like.
As the curing agent for the component (B), one kind may be used alone, or two or more kinds may be used in combination.

  In addition, the content of the component (B) is preferably 0.1 to 10 parts by mass, and 0.2 to 5 parts by mass per 100 parts by mass of the resin of the component (A) from the viewpoints of curability and storage stability. More preferred.

  The (C) filler used in the present invention contains conductive particles having a specific gravity of 1.1 to 5.0. The conductive particles preferably have a specific gravity of 1.1 to 4.0.

(C) When the specific gravity of the filler is in this range, sedimentation of the filler is suppressed during adjustment of the resin composition and sheet-like molding, and the filler is uniformly dispersed in the thickness direction of the sheet. This is preferable because an adhesive sheet is obtained.
(C) If the specific gravity of the filler is less than 1.1, the conductive metal content is low and there is a risk that sufficient firing will not be performed. If the specific gravity exceeds 5.0, the component (C) There is a possibility that the filler settles and is unevenly distributed on the lower side, so that sufficient thermal conductivity and electrical conductivity cannot be obtained.

  Examples of the filler (C) include a spherical metal powder such as a spherical aluminum powder, a powdered metal oxide such as a spherical silica powder, a spherical alumina powder, and a spherical titania powder, and the surface thereof is a conductive metal. Metal-coated powder coated with, and metal-coated powder having heat-resistant resin particles as the core and the surface coated with a conductive metal.

In the case of a metal-coated powder, the content of the conductive metal to be coated is preferably 10 to 60% by mass, and if the content is in this range, it has a low specific gravity and has good thermal conductivity and conductivity. A filler is obtained.
As the conductive metal, gold or silver is preferable, and silver-coated particles in which the surface of spherical silica is coated with silver at a content of 10 to 60% by mass are particularly preferable. Highly filled with silver-coated spherical silica provides a resin composition for adhering semiconductors that has good thermal conductivity and conductivity and a small difference in linear expansion coefficient from the semiconductor element.

In the present invention, the particle diameter of the filler (C) is preferably 1 to 10 μm in volume average particle diameter D ₅₀ by a laser diffraction / scattering particle size distribution measuring method. Furthermore, it is preferable that the aspect ratio defined by (the maximum major axis of the particle / the width orthogonal to the maximum major axis) is 1.0 to 1.2.
By using spherical particles having an aspect ratio in this range, a favorable conductive network is formed in the thickness direction of the sheet, which is preferable because thermal conductivity and conductivity can be improved. Furthermore, since the aspect ratio is in the above range, it becomes easy to uniformly coat the conductive metal on the particle surface, and thus there is an effect that problems such as peeling or cracking of the coated conductive metal hardly occur. .

The silver fine particles (D) used in the present invention are particles having an average particle size of 10 to 300 nm. The shape of the (D) silver fine particles can be any of spherical, scale-like, plate-like, needle-like, rod-like and the like, and is not particularly limited. Except for the spherical particles, the average particle diameter indicates the short side.
In addition, this average particle diameter is measured by arithmetic average about the particle diameter of what extracted 100 samples at random by TEM or SEM.

  The surface of the silver fine particles is preferably coated with an organic compound having a molecular weight of 20000 or less as a constituent element, specifically, an organic compound containing a functional group such as a carboxyl group or an amino group. Thereby, aggregation of silver fine particles is suppressed and dispersibility is improved.

  Examples of the organic compound containing a carboxyl group used here include one or more organic compounds selected from organic carboxylic acids having a molecular weight of 110 to 20000, such as hexanoic acid, heptanoic acid, octanoic acid, and nonanoic acid. And carboxylic acids such as decanoic acid, undecanoic acid, dodecanoic acid, tetradecanoic acid, eicosanoic acid, docosanoic acid, 2-ethylhexanoic acid, oleic acid, linoleic acid, linolenic acid, and terminal dipropionic acid polyethylene oxide. Furthermore, as the organic compound, a carboxylic acid derivative of the carboxylic acid described above can also be used.

  Examples of the organic compound containing an amino group used herein include alkylamines and the like, for example, butylamine, methoxyethylamine, 2-ethoxyethylamine, hexylamine, octylamine, 3-butoxypropylamine, nonylamine, dodecyl. Primary amines such as amines, hexadodecylamines, octadecylamines, cocoamines, tallowamines, hydroxylated tallowamines, oleylamines, laurylamines, stearylamines, 3-aminopropyltriethoxysilanes; dicocoamines, dihydrogenated tallowamines, di Secondary amines such as stearylamine; dodecyldimethylamine, didodecylmonomethylamine, tetradecyldimethylamine, octadecyldimethylamine, cocodimethylamine, dodecyltetra Tertiary amines such as sildimethylamine, trioctylamine, and others; naphthalenediamine, stearylpropylenediamine, octamethylenediamine, nonanediamine, terminal diamine polyethylene oxide, triamine-terminated polypropylene oxide, diamine-terminated polypropylene oxide, etc. There is a diamine.

When the molecular weight of the organic compound covering the silver fine particles is larger than 20000, the organic compound is less likely to be detached from the surface of the metal particles, and the above organic material is contained in the cured product after firing the adhesive sheet composed of the resin composition. The compound may remain, and as a result, the thermal conductivity and conductivity may decrease. Further, the molecular weight of the organic compound is preferably 50 or more. If the molecular weight is less than 50, the storage stability of the silver fine particles is inferior, which is not preferable.
Therefore, from the above viewpoint, the molecular weight of the organic compound covering the surface is preferably as small as possible as long as storage stability can be ensured.

  The silver fine particles preferably have a mass ratio of 90:10 to 99.5: 0.5 between the silver fine particles and the organic compound that coats or disperses the silver fine particles. At this time, if the amount of the organic compound is small relative to the silver fine particles, the suppression of aggregation becomes insufficient, and if the amount is large, the organic compound may remain in the cured product after firing. Decrease may occur.

  In the present invention, the ratio of the component (C) and the component (D) is such that the mass ratio of the component (C): the component (D) is 10:90 to 90:10, where the total amount is 100. Is preferable, and 50:50 to 90:10 is more preferable. If the amount of the component (D) is too small relative to the component (C), it is difficult to ensure high thermal conductivity, and if the amount of the component (D) is too large, voids may be generated in the cured product. There is a possibility that the conductivity is lowered.

  Here, the total amount of the filler of the component (C) and the silver fine particles of the component (D) is blended so as to be 40 to 80% by mass of the entire resin composition. If the total of the component (C) and the component (D) is less than 40% by mass, heat conductivity and conductivity may not be obtained, and if it exceeds 80% by mass, the resin composition may not function. It is not preferable.

Although this invention makes the said (A)-(D) component an essential component, in the range which does not inhibit the effect of this invention, you may contain the following other components.
In the present invention, (E) an organic substance as a flux component may be added. Here, the flux component means a material having a flux activity for removing an oxide film on a support member for joining a semiconductor element.

  Examples of the (E) flux component include carboxylic acids, and the carboxylic acids may be aliphatic carboxylic acids or aromatic carboxylic acids.

  Examples of the aliphatic carboxylic acid include malonic acid, methylmalonic acid, dimethylmalonic acid, ethylmalonic acid, allylmalonic acid, 2,2′-thiodiacetic acid, 3,3′-thiodipropionic acid, 2,2′- (Ethylenedithio) diacetic acid, 3,3′-dithiodipropionic acid, 2-ethyl-2-hydroxybutyric acid, dithiodiglycolic acid, diglycolic acid, acetylenedicarboxylic acid, maleic acid, malic acid, 2-isopropylmalic acid , Tartaric acid, itaconic acid, 1,3-acetone dicarboxylic acid, tricarbaric acid, muconic acid, β-hydromuconic acid, succinic acid, methyl succinic acid, dimethyl succinic acid, glutaric acid, α-ketoglutaric acid, 2-methylglutaric acid, 3-methylglutaric acid, 2,2-dimethylglutaric acid, 3,3-dimethylglutaric acid, 2,2-bis (hydroxy (Cimethyl) propionic acid, citric acid, adipic acid, 3-t-butyladipic acid, pimelic acid, phenyloxalic acid, phenylacetic acid, nitrophenylacetic acid, phenoxyacetic acid, nitrophenoxyacetic acid, phenylthioacetic acid, hydroxyphenylacetic acid, dihydroxyphenylacetic acid , Mandelic acid, hydroxymandelic acid, dihydroxymandelic acid, 1,2,3,4-butanetetracarboxylic acid, suberic acid, 4,4'-dithiodibutyric acid, cinnamic acid, nitrocinnamic acid, hydroxycinnamic acid, dihydroxycinnamic acid , Coumaric acid, phenylpyruvic acid, hydroxyphenylpyruvic acid, caffeic acid, homophthalic acid, tolylacetic acid, phenoxypropionic acid, hydroxyphenylpropionic acid, benzyloxyacetic acid, phenyllactic acid, tropic acid, 3- (phenylsulfonyl) propiate Acid, 3,3-tetramethylene glutaric acid, 5-oxoazeleic acid, azelaic acid, phenylsuccinic acid, 1,2-phenylenediacetic acid, 1,3-phenylenediacetic acid, 1,4-phenylenediacetic acid, benzyl Malonic acid, sebacic acid, dodecanedioic acid, undecanedioic acid, diphenylacetic acid, benzylic acid, dicyclohexylacetic acid, tetradecanedioic acid, 2,2-diphenylpropionic acid, 3,3-diphenylpropionic acid, 4,4-bis (4 -Hydroxyphenyl) valeric acid, pimaric acid, parastrinic acid, isopimaric acid, abietic acid, dehydroabietic acid, neoabietic acid, agatic acid and the like.

  Examples of the aromatic carboxylic acid include benzoic acid, 2-hydroxybenzoic acid, 3-hydroxybenzoic acid, 4-hydroxybenzoic acid, 2,3-dihydroxybenzoic acid, 2,4-dihydroxybenzoic acid, 2,5- Dihydroxybenzoic acid, 2,6-dihydroxybenzoic acid, 3,4-dihydroxybenzoic acid, 2,3,4-trihydroxybenzoic acid, 2,4,6-trihydroxybenzoic acid, 3,4,5-trihydroxy Benzoic acid, 1,2,3-benzenetricarboxylic acid, 1,2,4-benzenetricarboxylic acid, 1,3,5-benzenetricarboxylic acid, 2- [bis (4-hydroxyphenyl) methyl] benzoic acid, 1- Naphthoic acid, 2-naphthoic acid, 1-hydroxy-2-naphthoic acid, 2-hydroxy-1-naphthoic acid, 3-hydroxy-2-naphthoic acid, 6 Hydroxy-2-naphthoic acid, 1,4-dihydroxy-2-naphthoic acid, 3,5-dihydroxy-2-naphthoic acid, 3,7-dihydroxy-2-naphthoic acid, 2,3-naphthalenedicarboxylic acid, 2, Examples include 6-naphthalenedicarboxylic acid, 2-phenoxybenzoic acid, biphenyl-4-carboxylic acid, biphenyl-2-carboxylic acid, and 2-benzoylbenzoic acid.

  Among these, from the viewpoint of storage stability and availability, succinic acid, malic acid, itaconic acid, 2,2-bis (hydroxymethyl) propionic acid, adipic acid, 3,3′-thiodipropionic acid, 3 , 3′-dithiodipropionic acid, 1,2,3,4-butanetetracarboxylic acid, suberic acid, sebacic acid, phenylsuccinic acid, dodecanedioic acid, diphenylacetic acid, benzylic acid, 4,4-bis (4- Hydroxyphenyl) valeric acid, abietic acid, 2,5-dihydroxybenzoic acid, 3,4,5-trihydroxybenzoic acid, 1,2,4-benzenetricarboxylic acid, 1,3,5-benzenetricarboxylic acid, 2- [Bis (4-hydroxyphenyl) methyl] benzoic acid or the like is preferably used. These compounds may be used alone or in combination of two or more.

(E) As for a flux component, dicarboxylic acid is especially preferable, and the thing whose decomposition temperature is 100-300 degreeC, Preferably 150-290 degreeC is preferable.
Surface treatment agents such as stearic acid, palmitic acid, hexanoic acid, oleic acid, etc. present on the surface of component (C) and component (D) by the exchange reaction during bonding heating as well as removal of the oxide film on the supporting member to be bonded Since the dicarboxylic acid itself decomposes or evaporates at the same time as the removal of the oxide film and silver oxide contained therein, the subsequent sintering of silver is not hindered. By this, the sintering promotion effect that silver sinters at a lower temperature than before addition is obtained.

  If the boiling point of this (E) flux component is less than 100 ° C., the volatility will be high even at room temperature, so that the reduction ability is likely to decrease due to volatilization of the dispersion medium, and stable adhesive strength can be obtained. There is a risk of disappearing. Further, if the boiling point of the flux component (E) exceeds 300 ° C., it is difficult to sinter the conductive film, the denseness is lacking, and the flux component remains in the film without being volatilized.

  (E) As content of a flux component, it is preferable that it is 0.01-5 mass parts with respect to a total of 100 mass parts of (C) component and (D) component. If the content exceeds 5 parts by mass, the reliability due to the generation of voids may be adversely affected. If the content is less than 0.01 parts by mass, the flux activity may not function, which is not preferable.

  In the present invention, (F) nanocarbon may further be included. “Nanocarbon” means a minute carbon having a size of at least one side of 1000 nm or less (preferably 500 nm or less) in the shape of the material, for example, a carbon nanotube (single-walled / double-walled / multi-walled type) , Cup stack type), carbon nanofibers, and the like.

  Among these nanocarbons, carbon nanotubes are preferable because the fibrous protrusions act as tentacles, the silver particles can be connected to each other through ceramic particles, and the thermal conductivity can be effectively improved.

  The carbon nanotubes may be single wall carbon nanotubes or multi-wall carbon nanotubes. The average fiber length of the carbon nanotube is preferably 0.1 to 100 μm, more preferably 0.1 to 50 μm, and particularly preferably 0.1 to 20 μm. The average fiber diameter of the carbon nanotubes is preferably 5 to 200 nm, more preferably 8 to 160 nm, and particularly preferably 9 to 120 nm.

  Further, (F) the nanocarbon may be ceramic particles obtained by sintering so that the nanocarbon is dispersed and contained. The method for producing ceramic particles containing nanocarbon in a dispersed state is not particularly limited as long as the ceramic raw material particles containing dispersed nanocarbon are obtained. For example, a predetermined amount of nanocarbon and ceramic raw material particles are added. The method of mix | blending in a solvent, making it a slurry, drying this, and sintering is mentioned. At this time, a part of the nanocarbon protrudes from the ceramic surface of the particles.

(F) In the case of ceramic particles obtained by sintering so that nanocarbon is dispersed and contained as nanocarbon, the ceramic particles are preferably particles having an average particle diameter of 1 to 10 μm. Here, the average particle size refers to a 50% integrated value (D ₅₀ ) in the particle size distribution obtained on a volume basis by a laser diffraction / scattering particle size distribution measurement method.

  (F) By containing nanocarbon, the resin composition excellent in heat conductivity and electroconductivity is obtained when nanocarbon entangles in the network of the silver particle formed in the sheet-like resin composition.

  (F) It is preferable that the compounding quantity of a component is 5 mass% or less of the whole resin composition. When the blending amount of the component (F) exceeds 5% by mass, the viscosity increases and workability may be deteriorated. In addition, this compounding quantity is the quantity of only the nanocarbon contained in the ceramic particle.

  In the present invention, (G) a (meth) acrylic acid ester compound or a (meth) acrylamide compound further having a hydroxyl group may be included. By containing a hydroxyl group, the sinterability by the reduction effect is promoted and the adhesiveness is improved.

  Here, the component (G) has a (meth) acrylic acid ester compound or a (meth) acrylamide compound as a basic skeleton, and may have a substituent composed of an aliphatic hydrocarbon group having 4 to 100 carbon atoms. The hydroxyl group has an alcoholic group in which a hydrogen atom of an aliphatic hydrocarbon group is substituted. The hydroxyl group content is preferably 1 to 50 per molecule, and if the hydroxyl group content is within this range, there is no inhibition of sinterability due to excessive curing.

  The blending amount of the component (G) is preferably 1 to 20 parts by mass with respect to 100 parts by mass of the total amount of the filler of the component (C) and the silver fine particles of the component (D). By setting it as such a compounding range, favorable adhesive strength is obtained in the joining to the element support member of a semiconductor element. If this blending amount exceeds 20 masses, the resin content in the cured product layer increases, and thermal conductivity characteristics and specific resistance tend to decrease. If the blending amount is less than 1 part by mass, the adhesive strength tends to decrease. There is.

  In the present invention, (H) a coupling agent may be further contained. The coupling agent is not particularly limited. For example, 3-methacryloxypropyltrimethoxysilane, 3-acryloxypropyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (β-methoxyethoxy) silane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-aminopropyltriethoxysilane, N-phenyl-3- Examples include aminopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, titanate coupling agents, aluminum coupling agents, zirconate coupling agents, zircoaluminate coupling agents, and the like.

  The blending amount of the coupling agent as the component (H) is preferably in the range of 0.01 to 5% by mass, more preferably in the range of 0.05 to 4% by mass with respect to the entire resin composition. If it is less than 0.01% by mass, the effect of improving the adhesiveness cannot be obtained, and if it exceeds 5% by mass, a bleeding phenomenon may occur at the time of applying the paste, such being undesirable.

In the resin composition used in the present invention, in addition to each of the above components, a low stress such as a curing accelerator, rubber or silicone, which is generally blended in this type of composition within a range not inhibiting the effects of the present invention. Agents, coupling agents, antifoaming agents, surfactants, colorants (pigments, dyes), various polymerization inhibitors, antioxidants, and other various additives can be blended as necessary.
Each of these additives may be used alone or in combination of two or more.

  Such additives include silane coupling agents such as epoxy silane, mercapto silane, amino silane, alkyl silane, clade silane, vinyl silane, sulfide silane, titanate coupling agent, aluminum coupling agent, aluminum / zirconium coupling agent. Coupling agents such as carbon black, colorants such as carbon black, solid stress reducing components such as silicone oil and silicone rubber, and inorganic ion exchangers such as hydrotalcite.

  The resin composition for semiconductor bonding used in the present invention can be produced by applying a known method. For example, the above components (A) to (D) and various components blended as necessary may be mixed at room temperature using a known kneader such as a pot mill, a ball mill, a bead mill, a roll mill, a homogenizer, a super mill, or a likai machine. Or after kneading | mixing under a heating, it dilutes with a solvent as needed and is obtained.

  Next, the semiconductor bonding sheet of the present invention will be described. The semiconductor bonding sheet of the present invention is a molded product obtained by molding the semiconductor bonding resin composition into a sheet shape. This semiconductor bonding sheet is suitable for bonding a semiconductor and a support member, and can exhibit good conductivity and thermal conductivity, particularly by bonding by sintering.

The method for producing a semiconductor bonding sheet of the present invention comprises preparing a viscosity of about 0.5 to 2 Pa · s in a resin composition for semiconductor bonding obtained by diluting a solvent as described above, and then on a support film. It is obtained by coating by a known method and drying.
Specifically, it is applied on a support film by a known coating method such as a bar coating method, a knife coating method, a roll coating method, a blade coating method, a die coating method, a gravure coating method, a drying treatment, and a semi-cured state. Can be obtained.

  As the support film, a plastic film such as polyethylene, polypropylene, polyester, polycarbonate, polyarylate, polyacrylonitrile, etc., provided with a release agent layer on one side is used. The thickness of this support film is usually 10 to 50 μm, preferably 25 to 38 μm, from the viewpoint of handling properties.

  Moreover, it is preferable to apply | coat the sheet | seat for semiconductor adhesion obtained by the said method so that the thickness after drying of the contact bonding layer which consists of the said resin composition may be 5-50 micrometers, and it is more preferable that it is 10-30 micrometers.

  The semiconductor device of the present invention is formed by bonding a semiconductor element onto a support member such as a substrate using the above-described semiconductor bonding sheet. That is, here, the semiconductor bonding sheet is used as a thermally conductive / conductive die attach sheet.

  The semiconductor device of the present invention is, for example, temporarily attached to a bonding surface of a silicon chip under conditions of a temperature of 50 to 80 ° C., a pressure of 0.1 to 1 MPa, and a heating and pressing time of 0.1 to 1 minute, and then a copper frame. It is mounted on a supporting member such as 80 ° C. to 200 ° C., pressure 0.1-5 MPa, heat pressurizing time 0.1-1 min. It can be produced by heating and curing for ˜2 hours.

  Here, examples of the semiconductor element include known semiconductor elements such as a transistor, a diode, and a light emitting element, and are particularly suitable for a power semiconductor element such as a silicon carbide (SiC) device. Examples of the support member include copper, silver-plated copper, PPF (preprating lead frame), glass epoxy, ceramics, DBC substrate, and the like.

  The semiconductor device thus obtained is bonded to the support member with a semiconductor bonding sheet having excellent thermal conductivity and conductivity, so that no voids are formed on the support member, and the adhesive to the side surface is not formed. There is no creeping up and it is effective in reducing the size. Furthermore, the connection reliability with respect to the temperature cycle after mounting is also good.

(Production Example 1)
<Preparation of spherical silver-coated silica particles>
10 g of spherical silica particles (trade name: US-5, manufactured by Tatsumori Co., Ltd.) having a volume average particle size D ₅₀ of 3.5 μm are alkali degreased, acid neutralized and etched, washed with water, and added to a palladium dichloride solution. , Stirred to obtain palladium-adhered substrate particles.

  The obtained base particles were stirred in 300 mL of deionized water for 3 minutes, 1 g of metal nickel particle slurry (Mitsui Metal Mining Co., Ltd., trade name: 2020SUS) was added, and nickel was precipitated using palladium as a catalyst nucleus, Nickel particle adhesion base particles were obtained.

The obtained substrate particles were diluted with 1000 mL of distilled water, and 4 mL of a plating stabilizer was added and stirred.
Thereafter, 150 mL of a mixed solution of 400 g / L of nickel sulfate, 100 g / L of sodium hypophosphite, 100 g / L of sodium citrate, and 6 mL of a plating stabilizer is gradually added to the substrate particle mixed solution while stirring. A nickel coating as an underlayer was formed on the particles. The liquid after plating was filtered, and the filtrate was washed with water and dried to obtain nickel-coated substrate particles.

The obtained nickel-coated substrate particles were prepared by mixing 5 g of silver nitrate, 1200 mL of distilled water, and 10 g of benzimidazole, further mixing and dissolving 30 g of succinimide and 4 g of citric acid, and adding 10 g of glyoxylic acid. It put into the silver plating solution. After heating and stirring at 80 ° C. to perform electroless plating, the film was washed with water, and the silver-coated particles substituted with alcohol were dried to obtain silver-coated silica particles. The obtained silver-coated silica particles have an aspect ratio of 1.01, a specific surface area of 1.5 m ² / g, a volume average particle diameter D ₅₀ = 3.8 / μm, and a volume average particle diameter ratio D ₅₀ / D ₁₀ = 1. The maximum particle size was 19 μm, the specific gravity was 2.8, and the silver coating amount was 27.3 mass%.

<Examples 1-3, Comparative Examples 1-4>
After thoroughly mixing each component at the blending ratio shown in Table 1 and kneading with three rolls to prepare a resin composition, propylene glycol monomethyl ether (PGM) and methyl ethyl ketone were added as a solvent, and the solid content was 40% by mass. A resin composition was prepared.

  The obtained resin composition was applied and dried on a polypropylene film having a thickness of 40 μm with a roll coater so that the thickness after drying was 15 μm, thereby obtaining a semiconductor bonding sheet.

Component (A) (A1): Solid bismaleimide resin having an aliphatic hydrocarbon group in the main chain (manufactured by Designer Molecules, Inc., trade name: BMI-5000; number average molecular weight 5000)
(A2): Liquid bismaleimide resin having an aliphatic hydrocarbon group in the main chain (manufactured by Designer Molecules, Inc., trade name: BMI-1500; number average molecular weight 1500)
Component (B): Dicumyl peroxide (Nippon Yushi Co., Ltd., trade name: Park Mill D)
Component (C): Spherical silver-coated silica particles according to Production Example 1 (average particle size: 3.8 μm, specific gravity: 2.8)
Other fillers: Silver particles (Fukuda Metal Foil Powder Co., Ltd., trade name: AgC-212D, average particle diameter: 5 μm, specific gravity: 10.5)
Component (D) (Dl): Plate-type silver fine particles (manufactured by Toxen Industries, Ltd., trade name: M13; center particle size: 2 μm, thickness: 50 nm or less)
(D2): Spherical silver fine particles (manufactured by Mitsuboshi Belting Ltd., trade name: MDot; average particle diameter: 50 nm)

(E) component: malic acid (F) component: carbon nanotube (manufactured by Showa Denko KK, trade name: VGCF; average fiber diameter: 80 nm, average fiber length: 10 μm)
(G) Component: Hydroxylethylacrylamide (manufactured by Kojin Co., Ltd., trade name: HEAA)
Component (H): Glycidoxyoctyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name: KBM-4803)

<Evaluation method>
[Handling]
The obtained semiconductor bonding sheet was bent 180 degrees and evaluated according to the following criteria.
○: No cracking or peeling from film △: No peeling from film, but abnormal appearance ×: Cracking or peeling from film occurred

[Tackiness]
When a semiconductor bonding sheet is pressure-bonded to a 6 mm × 6 mm silicon chip and a backside gold chip having a gold vapor deposition layer on the bonding surface under the conditions of 65 ° C., 1 second and pressure 1 MPa, ○ is pasted. The case where it was impossible was determined as x.

[Heat bond strength]
A semiconductor bonding sheet was temporarily attached to a 6 mm × 6 mm silicon chip and a back gold chip provided with a gold deposition layer on the bonding surface at 65 ° C. for 1 second and a pressure of 1 MPa, and then a solid copper frame and PPF (Ni— (Pd / Au plated copper frame), pressure-pressed by heating at 125 ° C. for 5 seconds and a pressure of 0.1 MPa, and further cured in an oven at 220 ° C. for 1 hour.
After curing and moisture absorption treatment (85 ° C., relative humidity 85%, 72 hours), the hot die shear strength at 260 ° C. was measured using a mount strength measuring device.

[Thermal conductivity]
According to JIS R 1611-1997, the thermal conductivity of the cured product was measured by a laser flash method.

[Electric resistance]
The semiconductor bonding sheet was attached to a glass substrate (thickness 1 mm) under the conditions of 65 ° C., 1 second and pressure 1 MPa, and cured at 200 ° C. for 60 minutes. The electrical resistance of the obtained wiring was measured by a 4-terminal method using MCP-T600 (trade name, manufactured by Mitsubishi Chemical Corporation).

[Package crack resistance]
(1) IR reflow resistance A 6 mm x 6 mm silicon chip is mounted on a copper frame and PPF via a semiconductor bonding sheet, and heated and cured on a hot plate at 200 ° C for 60 seconds under a pressure of 2.5 MPa (HP Curing) or using an oven, heat curing (OV curing) at 200 ° C. for 60 minutes and a pressure of 2.5 MPa was performed. This was subjected to a moisture absorption treatment at 85 ° C. and a relative humidity of 85% for 168 hours using an epoxy sealing material (trade name: KE-G3000D) manufactured by Kyocera Chemical Co., Ltd., followed by an IR reflow treatment (260 And the number of internal cracks in the package was observed with an ultrasonic microscope.
The number of samples in which cracks occurred for five samples is shown.
(2) Cold and thermal shock resistance Using the above sample piece, a cold cycle treatment (the operation of raising the temperature from −55 ° C. to 150 ° C. and cooling to −55 ° C. as one cycle, which is 1000 cycles) is performed, After each treatment, the number of occurrences of internal cracks in each package was observed with an ultrasonic microscope.
The number of samples in which cracks occurred for five samples is shown.
Detailed test specimen preparation conditions are as follows.
Package: 80pQFP (14mm x 20mm x 2mm thickness)
Chip: Silicon chip and gold-plated chip on the back surface Lead frame: PPF and copper Molding of sealing material: 175 ° C., 2 minutes Post mold cure: 175 ° C., 8 hours

[Void rate]
Observed using a microfocus X-ray inspection apparatus (manufactured by Shimadzu Corporation, trade name: SMX-1000), the void ratio is less than 5% as “◯”, 5% to less than 8% as “△”, 8% The above was evaluated as “x”. In addition, the said void rate observed the solder joint part from the orthogonal | vertical direction with respect to the joint surface with the X-ray transmissive apparatus, calculated | required the void area and the joint part area, and computed it with the following formula.
Void ratio (%) = void area / (void area + joint area) × 100

The results of these characteristic evaluations are shown in Table 1 together with the composition of the semiconductor adhesive resin composition.

  As mentioned above, it turned out that the resin composition useful as an adhesive material which can express the outstanding heat conductivity and electroconductivity is obtained. Therefore, a semiconductor device in which a semiconductor element is bonded onto a support member with this resin composition has excellent thermal conductivity and conductivity with the semiconductor element on the support member, and can be joined without generating fillets. As described above, the resin composition used in the present invention is excellent for semiconductor bonding (particularly for power semiconductor bonding), and by using this, a highly reliable semiconductor device with improved efficiency can be provided. .

Claims (6)

(A) a bismaleimide resin having an aliphatic hydrocarbon group in the main chain;
(B) a curing agent;
(C) a filler containing conductive particles having a specific gravity of 1.1 to 5.0;
(D) silver fine particles having an average particle diameter of 10 to 300 nm;
A semiconductor bonding sheet, which is formed by molding a resin composition for bonding semiconductors containing as a necessary component into a sheet shape. The bismaleimide compound (A1) in which the component (A) is represented by the following general formula (1)

(Wherein, n represents an integer of 1 to 10). The (A) component is a bismaleimide compound (A2) represented by the following general formula (2)

(In the formula, Q represents a divalent linear, branched or cyclic aliphatic hydrocarbon group having 6 or more carbon atoms, and P represents O, CO, COO, CH ₂ , C (CH ₃ ) _2. , C (CF ₃ ) ₂ , S, S ₂ , SO and SO ₂ or a divalent atom or an organic group, or an organic group containing at least one or more of these atoms or organic groups, m is 1 to 3. The sheet for semiconductor adhesion according to claim 1 or 2, which represents an integer of 10.   The sheet for semiconductor adhesion according to any one of claims 1 to 3, wherein the component (C) is silver-coated particles having a silver content of 10 to 60% by mass.   The sheet for semiconductor adhesion according to any one of claims 1 to 4, wherein the component (C) is silver-coated silica.   A semiconductor device comprising a semiconductor element bonded onto a support member via the semiconductor bonding sheet according to claim 1.