JP2021036022A - Thermoconductive adhesive sheet, and semiconductor device - Google Patents

Abstract

To provide a thermoconductive adhesive sheet excellent in temporary adhesiveness and sheet performance, having a high thermal conductivity even under low-temperature sintering conditions, and capable of giving a semiconductor device excellent in reliability, and provide a semiconductor device having a semiconductor element bonded with the thermoconductive adhesive sheet.SOLUTION: A thermoconductive adhesive sheet is obtained by forming a resin composition containing (A) silver particles, (B) a thermosetting resin, and (C) a binder resin into a sheet. The silver particles (A) are secondary particles formed through aggregation of particles that contain primary particles having an average particle size of 10 to 100 nm.SELECTED DRAWING: None

Description

The present invention relates to a heat conductive adhesive sheet and a semiconductor device.

In recent years, due to increasing awareness of environmental issues, power semiconductor devices have come to be widely used not only for general industrial applications and electric railway applications but also for in-vehicle applications. In particular, for in-vehicle parts, making each part smaller and lighter within the limited allowable size is directly linked to the performance of the vehicle, so reducing the size is a very important issue for power semiconductor devices as well. 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 via high-lead solder having high heat resistance. However, the use of harmful substances including lead has been regulated, and lead-free use is required.

As a highly 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 (see, for example, Patent Document 1). ). Sintered silver paste has high thermal conductivity and is effective for joining power semiconductor devices that handle large currents. However, from the viewpoint of miniaturization and thinning of semiconductor devices, a sheet material having a thin bonding material is desired.

Since the thermal conductivity of solder is generally 30 W / m · K, a sheet material having high thermal conductivity that can replace it is required, and such a sheet material is also provided (for example, a patent). Reference 2).

International Publication No. 2015/151136 Special Table 2016-536467

However, there are few sheet materials on the market that have high thermal conductivity. This is because if the sheet material tries to exhibit thermal conductivity comparable to that of the solder material, the reaction may deteriorate the reliability characteristics such as the thermal cycle test, which is described in Patent Document 2 above. There is room for improvement in the sheet material. Furthermore, in order to exhibit high thermal conductivity characteristics, it is necessary to raise the sintering temperature to 250 ° C. or higher in order to sinter the particles contained in the sheet. Considering the heat resistance of peripheral members, sintering at a lower temperature (200 ° C. or lower) is required.
By the way, the sheet material containing nano-sized silver particles is excellent in low-temperature sinterability, but the temporary adhesiveness becomes a problem, and the sheet material containing micro-sized silver particles has a problem in sheet property. Furthermore, in order to develop thermal conductivity using silver particles, it is necessary to lower the viscosity of the resin component, and the tackiness of the sheet material becomes a problem, but the viscosity is such that the tackiness of the sheet material does not become a problem. Then, the temporary adhesiveness is lowered.

The present invention has been made in view of such circumstances, and has excellent temporary adhesiveness and sheet properties, high thermal conductivity even under low-temperature sintering conditions, and high heat that enables a highly reliable semiconductor device to be obtained. An object of the present invention is to provide a semiconductor device in which semiconductor elements are bonded by a conductive adhesive sheet.

As a result of diligent studies to solve the above-mentioned problems, the present inventor has found that the above-mentioned problems can be solved by the following inventions.
The present invention has been completed based on such findings.

That is, the disclosure of the present application relates to the following.
[1] A heat conductive adhesive sheet obtained by molding a resin composition containing (A) silver particles, (B) a thermosetting resin, and (C) a binder resin into a sheet shape.
The silver particles (A) are heat conductive adhesive sheets, which are secondary particles in which particles including primary particles having an average particle diameter of 10 to 100 nm are aggregated.
[2] The heat conductive adhesive sheet according to the above [1], wherein the silver particles (A) have a positive coefficient of thermal expansion between 150 ° C. and 300 ° C.
[3] The heat conductive adhesive sheet according to the above [1] or [2], wherein the silver particles (A) have a tap density of 4.0 to 7.0 g / cm ^3.
[4] The heat conductive adhesive according to any one of the above [1] to [3], wherein the silver particles (A) have a specific surface area of 0.5 to 1.5 m ^{2 / g determined by the BET method.} Sheet.
[5] The heat conductive adhesive sheet according to any one of the above [1] to [4], wherein the average particle size of the silver particles (A) is 0.5 to 5.0 μm.
[6] The heat conductive adhesive sheet according to any one of the above [1] to [5], wherein the (B) thermosetting resin is a liquid or a solid material having a softening point of 70 ° C. or lower.
[7] The heat according to any one of the above [1] to [6], wherein the (B) thermosetting resin is at least one selected from the group consisting of an epoxy resin, a cyanate resin, a maleimide resin, and an acrylic resin. Conductive adhesive sheet.
[8] The binder resin (C) has a weight average molecular weight of 200,000 to 1,000,000 and a glass transition temperature of −40 ° C. to 0 ° C., any of the above [1] to [7]. The heat conductive adhesive sheet described in.
[9] The total content of the (B) thermosetting resin content and the (C) binder resin content is 5 to 30% by mass with respect to the total amount of the resin composition, and the above (A). ) The thermosetting adhesive sheet according to any one of the above [1] to [8], wherein the content of silver particles is 30 to 95% by mass.
[10] After the resin composition is cured, the elastic modulus is 3 GPa or less, the glass transition temperature (Tg) is 0 ° C. or less, and the thermal expansion coefficient is −50 to −40 ° C. and 140 ° C. to 150 ° C. The heat conductive adhesive sheet according to any one of the above [1] to [9], which is 50 ppm / ° C. or less.
[11] The heat conductive adhesive sheet according to any one of the above [1] to [10], wherein the cured product obtained by curing the resin composition at 200 ° C. or lower has a thermal conductivity of 30 W / m · K or more. ..
[12] The support member, the cured product of the heat conductive adhesive sheet provided on the support member according to any one of the above [1] to [11], and the cured product of the heat conductive adhesive sheet. A semiconductor device having a semiconductor element bonded onto the support member via an object.

According to the present invention, a semiconductor element is bonded by a high thermal conductive adhesive sheet which is excellent in temporary adhesiveness and sheet property, has high thermal conductivity even under low temperature sintering conditions, and can obtain a semiconductor device having excellent reliability. A semiconductor device can be provided.

Hereinafter, the present invention will be described in detail with reference to one embodiment.

<Sheet for thermal conductivity adhesive>
The heat conductive adhesive sheet of the present embodiment is formed by molding a resin composition containing (A) silver particles, (B) a thermosetting resin, and (C) a binder resin into a sheet shape. The silver particles (A) are characterized in that they are composed of secondary particles in which particles including primary particles having an average particle diameter of 10 to 100 nm are aggregated.

[(A) Silver particles]
The silver particles (A) are composed of secondary particles in which particles including primary particles having an average particle diameter of 10 to 100 nm are aggregated. The silver particles (A) may be silver particles composed of secondary particles in which primary particles having the average particle size are aggregated, and primary particles having the average particle size and average particles larger than the average particle size. It may be silver particles composed of secondary particles in which particles including particles having a diameter are aggregated.
If the average particle size of the primary particles is less than 10 nm, the specific surface area may increase and the sheet may become brittle, and if it exceeds 100 nm, the sinterability may decrease. From this point of view, the average particle size of the primary particles is preferably 10 to 50 nm, more preferably 20 to 50 nm.
The average particle size of the primary particles was measured by observing the cross section of spherical silver particles cut with a focused ion beam (FIB) device with a field emission scanning electron microscope (FE-SEM). It can be obtained by averaging the number of particle sizes, and specifically, it can be measured by the method described in Examples.
The silver particles (A) are further composed of silver particles having a positive coefficient of thermal expansion between 150 ° C. and 300 ° C., which is a firing temperature range. The coefficient of thermal expansion of the silver particles (A) may be 0.2 to 10.0 ppm / ° C. or 1.5 to 8.0 ppm / ° C.
In the present disclosure, in order to obtain the coefficient of thermal expansion of silver particles, a mini hydraulic press (manufactured by Specac) was used to apply a load of 200 kgf to Ag powdered silver particles for 1 minute to obtain a diameter of 5 mm and a thickness of 1 mm. A columnar pellet type sample is prepared, and the obtained sample is heated from room temperature to a heating rate using a thermomechanical analysis (TMA) device (manufactured by Seiko Instruments Co., Ltd., trade name: TMA SS150). The coefficient of thermal expansion when the thermal expansion is measured under the condition of raising the temperature to 350 ° C. at 20 ° C./min and the pellet length at 25 ° C. is used as a reference, is between 150 ° C. and 300 ° C., which is the firing temperature range. The coefficient of thermal expansion was calculated.
The sintering start temperature of silver particles having a positive coefficient of linear expansion is the temperature at which shrinkage starts, that is, the temperature at which the coefficient of thermal expansion is maximized, and the temperature range is usually 150 to 300 ° C. Between.
When the temperature at which the coefficient of thermal expansion is shown is in this range, the heat conductive adhesive sheet has good sinterability because silver fine particles expand during sintering, which increases the chances of contact between silver particles. Thermal conductivity is obtained.
In particular, the heat conductive adhesive sheet containing a binder resin as an essential component has a small proportion of reactive functional groups in the resin composition, and therefore has a small volume exclusion effect due to resin curing shrinkage. Therefore, silver at the time of silver particle sintering. Since the effect of promoting sintering due to the proximity of the particles is small and the degree of freedom of the silver particles is small, high thermal conductivity can be obtained by including the silver particles having a positive coefficient of thermal expansion.

The average particle size of the silver particles (secondary particles) (A) is preferably 0.5 to 5.0 μm, more preferably 0.5 to 3.0 μm, and more preferably 1.0 to 3. It is 0.0 μm. When the average particle size of the secondary particles is 0.5 μm or more, the storage stability is good, and when it is 5.0 μm or less, the sinterability is improved.
The average particle size of the secondary particles is a particle size (50% particle size D50) at which the integrated volume is 50% in the particle size distribution measured using a laser diffraction type particle size distribution measuring device. It can be measured by the method described in the examples.

The tap density of the silver particles (A) is preferably 4.0 to 7.0 g / cm ³ , more preferably 4.5 to 7.0 g / cm ³ , and even more preferably 4.5 to 6. It is .5 g / cm ³ . When the tap density of the silver particles (A) is 4.0 g / cm ³ or more, the silver particles can be highly filled in the resin composition, and ^{when the tap density is 7.0 g / cm 3} or less, the sheet is prepared. It is possible to prevent the silver particles from settling.
The tap density of the silver particles (A) can be measured using a tap density measuring device, and specifically, can be measured by the method described in Examples.

The specific surface area of the silver particles (A) determined by the BET method is preferably 0.5 to 1.5 m ² / g, more preferably 0.5 to 1.2 m ² / g, and even more preferably. It is 0.6 to 1.2 m ² / g. When the specific surface area is 0.5 m ² / g or more, the sheet can be suppressed from stickiness, and when it is 1.5 m ² / g or less, the temporary adhesiveness is improved.
The specific surface area of the silver particles (A) can be measured by the BET one-point method by nitrogen adsorption using a specific surface area measuring device, and specifically, can be measured by the method described in Examples.

Since the silver particles are secondary particles in which particles containing nano-sized primary particles are aggregated, the high activity of the surface of the primary particles is maintained, and the sinterability between the secondary particles at a low temperature (A). Self-sintering property). Further, the sintering of the silver particles and the sintering of the silver particles and the joining member proceed in parallel. Therefore, by using the silver particles (A), a heat conductive adhesive sheet having excellent thermal conductivity and adhesive properties can be obtained.

The shape of the silver particles (A) is not particularly limited, and examples thereof include spherical, flake-shaped, and scales, and among them, spherical is preferable.
Further, the silver particles (A) may be hollow particles or solid particles. Here, the hollow particle means a particle having voids inside the particle. When the silver particles (A) are hollow particles, it is particularly preferable that a void is present in the central portion of the silver particles. Further, the solid particle means a particle having substantially no space inside the particle.

((A) Method for producing silver particles)
The method for producing the silver particles (A) is not particularly limited, but for example, a step of adding ammonia water to an aqueous solution containing a silver compound to obtain a silver ammine complex solution, and a step of obtaining the silver ammine complex solution in the silver ammine complex solution obtained in the above step. A step of reducing the silver ammine complex with a reducing compound to obtain a silver particle-containing slurry, and a step of adding an organic protective compound to the silver particle-containing slurry obtained in the above step and introducing a protective group into the silver particles. , Have.

(Step to obtain silver ammine complex solution)
In this step, aqueous ammonia is added to an aqueous solution containing a silver compound to obtain a silver ammine complex solution.
Examples of the silver compound include silver nitrate, silver chloride, silver acetate, silver oxalate, silver oxide and the like. Of these, silver nitrate and silver acetate are preferable from the viewpoint of solubility in water.

The amount of ammonia added is preferably 2 to 50 mol, more preferably 5 to 50 mol, and further preferably 10 to 50 mol per 1 mol of silver in the aqueous solution containing the silver compound. When the amount of ammonia added is within the above range, the average particle size of the primary particles can be within the above range.

The silver ammine complex solution thus obtained may contain silver powder having an average particle size of 0.5 to 20 μm.

(Step to obtain silver particle-containing slurry)
In this step, the silver ammine complex in the silver ammine complex solution obtained in the above step is reduced with a reducing compound to obtain a silver particle-containing slurry.
By reducing the silver ammine complex with a reducing compound, the primary particles of the silver particles in the silver ammine complex are aggregated to form secondary particles (hollow particles) having a void in the center. Further, in the above step, when the silver ammine complex solution contains silver powder having an average particle diameter of 0.5 to 20 μm, the secondary particles in which the primary particles of the silver particles in the silver ammine complex are aggregated around the silver powder (secondary particles). Solid particles) are formed.

By appropriately adjusting the amount of silver in the silver ammine complex and the content of the reducing compound, the aggregation of the primary particles can be controlled, and the average particle size of the obtained secondary particles is within the above range. can do.

The reducing compound is not particularly limited as long as it has a reducing power for reducing the silver ammine complex and precipitating silver. Examples of the reducing compound include hydrazine derivatives.
Examples of the hydrazine derivative include hydrazine monohydrate, methylhydrazine, ethylhydrazine, n-propylhydrazine, i-propylhydrazine, n-butylhydrazine, i-butylhydrazine, sec-butylhydrazine, t-butylhydrazine, n. -Pentylhydrazine, i-pentylhydrazine, neo-pentylhydrazine, t-pentylhydrazine, n-hexylhydrazine, i-hexylhydrazine, n-heptylhydrazine, n-octylhydrazine, n-nonylhydrazine, n-decylhydrazine, n -Undecyl hydrazine, n-dodecyl hydrazine, cyclohexyl hydrazine, phenyl hydrazine, 4-methylphenyl hydrazine, benzyl hydrazine, 2-phenylethyl hydrazine, 2-hydrazinoethanol, acetohydrazine and the like can be mentioned. These may be used alone or in combination of two or more.

The content of the reducing compound is preferably 0.25 to 20 mol, more preferably 0.25 to 10 mol, and further preferably 1.0 to 5.0 mol per 1 mol of silver in the silver ammine complex. When the content of the reducing compound is within the above range, the average particle size of the obtained secondary particles can be within the above range.

(Step of introducing protecting groups into silver particles)
In this step, an organic protective compound is added to the silver particle-containing slurry obtained in the above step, and a protecting group is introduced into the silver particles.
Examples of the organic protective compound include carboxylic acids, amines, amides and the like. Of these, a carboxylic acid is preferable from the viewpoint of enhancing dispersibility.
Examples of the carboxylic acid include monocarboxylic acids such as formic acid, acetic acid, propionic acid, butyric acid, valeric acid, hexanoic acid, capric acid, octyl acid, nonanoic acid, capric acid, oleic acid, stearic acid and isostearic acid; , Malonic acid, succinic acid, glutaric acid, adipic acid, pimelli acid, suberic acid, azelaic acid, sebacic acid, diglycolic acid and other dicarboxylic acids; Aromatic carboxylic acids; examples thereof include glycolic acid, lactic acid, tartronic acid, malic acid, glyceric acid, hydroxybutyric acid, tartrate acid, citric acid, hydroxy acid such as isocitrate.

The blending amount of the organic protective compound is preferably 1 to 20 mmol, more preferably 1 to 10 mmol, and further preferably 1 to 5 mmol with respect to 1 mol of the silver particles. When the blending amount of the organic protective compound is 1 mmol or more, the silver particles can be dispersed in the resin, and when it is 20 mmol or less, the silver particles can be dispersed in the resin without impairing the sinterability.

The content of the silver particles (A) is preferably 30 to 95% by mass, more preferably 30 to 80% by mass, and further preferably 35 to 70% by mass with respect to the total amount of the resin composition. .. (A) When the content of the silver particles is 30% by mass or more, the thermal conductivity can be improved, and when it is 95% by mass or less, the adhesive strength can be improved.

[(B) Thermosetting resin]
The thermosetting resin (B) can be used without particular limitation as long as it is a thermosetting resin generally used for adhesives. Among them, a liquid or a solid material having a softening point of 70 ° C. or lower is preferable, and a resin that is liquid at room temperature (25 ° C.) is more preferable. The thermosetting resin (B) is preferably at least one selected from the group consisting of epoxy resin, cyanate resin, maleimide resin and acrylic resin from the viewpoint of adhesive use, and epoxy resin is more preferable. These may be used alone or in combination of two or more.

Epoxy resin is a compound having one or more glycidyl groups in the molecule, and is a resin that forms a three-dimensional network structure and is cured by reacting the glycidyl groups by heating. It is preferable that two or more glycidyl groups are contained in one molecule, because a compound having only one glycidyl group cannot exhibit sufficient cured product properties even if it is reacted. A compound containing two or more glycidyl groups in one molecule can be obtained by epoxidizing a compound having two or more hydroxyl groups. Examples of such compounds include bisphenol compounds such as bisphenol A, bisphenol F, and biphenol or derivatives thereof, hydrogenated bisphenol A, hydrogenated bisphenol F, hydrogenated biphenol, cyclohexanediol, cyclohexanedimethanol, and alicyclic such as cyclohexanediethanol. Bifunctional diols having a structure or derivatives thereof, butane diols, hexane diols, octane diols, nonane diols, aliphatic diols such as decane diols or epoxidized derivatives thereof, trihydroxyphenylmethane skeletons, aminophenols Examples include trifunctional compounds in which a compound having a skeleton is epoxidized, and polyfunctional compounds in which phenol novolac resin, cresol novolac resin, phenol aralkyl resin, biphenyl aralkyl resin, naphthol aralkyl resin, etc. are epoxidized. Not limited.

Among the above epoxy resins, a liquid epoxy resin and a solid epoxy resin having a softening point of 70 ° C. or lower are preferably used, but a liquid epoxy resin is more preferable. Here, the liquid epoxy resin refers to an epoxy resin in a liquid or semi-solid state at room temperature (25 ° C.), and examples thereof include an epoxy resin having fluidity at room temperature (25 ° C.). The viscosity of the liquid epoxy resin at 25 ° C. is preferably 100,000 mPa · s or less, more preferably 10,000 to 60,000 mPa · s.
The viscosity of the liquid epoxy resin at 25 ° C. can be measured with a rotary viscometer.

The weight average molecular weight (Mw) of the liquid epoxy resin is preferably 300 to 3,000, more preferably 500 to 1,000, from the viewpoint of fluidity and flexibility. Here, in the present specification, Mw is a value obtained by converting a chromatogram measured by gel permeation chromatography (GPC) into a molecular weight of standard polystyrene.

As the liquid epoxy resin, a biphenyl aralkyl resin is preferable. The biphenyl aralkyl resin is an epoxy resin having a biphenyl skeleton, but the biphenyl skeleton in the present embodiment also includes a biphenyl ring obtained by hydrogenating at least one aromatic ring.

Specific examples of the biphenyl aralkyl resin include 4,4'-bis (2,3-epoxypropoxy) biphenyl and 4,4'-bis (2,3-epoxypropoxy) -3,3', 5,5. '-Tetramethylbiphenyl, 4,4'-(3,3', 5,5'-tetramethyl) biphenyl, epichlorohydrin and 4,4'-biphenol, or 4,4'-(3,3', 5, Examples thereof include an epoxy resin obtained by reacting with a biphenol compound such as 5'-tetramethyl) biphenol. Among these, 4,4'-bis (2,3-epoxypropoxy) -3,3', 5,5'-tetramethylbiphenyl, 4,4'-(3,3', 5,5'- Glycidyl ether of tetramethyl) biphenyl is preferred. One type of biphenyl aralkyl resin may be used, or two or more types may be mixed and used.

Examples of commercially available products used as biphenyl aralkyl resins include YX7105 manufactured by Mitsubishi Chemical Holdings, Inc. By using a liquid epoxy resin, particularly a biphenyl aralkyl resin, it is possible to easily maintain the melt viscosity of the resin composition in a suitable range even when the silver particles (A) described above are highly filled, and the heat resistance is further excellent. A heat conductive adhesive sheet can be obtained.

By combining the above liquid epoxy resin and the silver particles (A), the sheet property is good without cracking or peeling, and the appropriate tack property is exhibited at 50 to 80 ° C. Therefore, the temporary adhesive property is exhibited. Will be good. It is presumed that the surface area of the silver particles retains the liquid component at room temperature, and the resin component softens at the temperature at the time of temporary attachment to exhibit such good sheet properties.

Examples of the curing agent for the epoxy resin include aliphatic amines, aromatic amines, dicyandiamides, dihydrazide compounds, acid anhydrides, and phenol resins. Aromatic amines include diaminodiphenylmethane, m-phenylenediamine, diaminodiphenylsulfone, diethyltoluenediamine, trimethylenebis (4-aminobenzoate), polytetramethylene oxide-di-p-aminobenzoate, and 4,4. '-Diamino-3,3'-diethyldiphenylmethane and the like can be mentioned. Examples of the dihydrazide compound include carboxylic acid dihydrazides such as adipic acid dihydrazide, dodecanoic acid dihydrazide, isophthalic acid dihydrazide, and p-oxybenzoic acid dihydrazide.
Acid anhydrides include phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, endomethylenetetrahydrophthalic anhydride, dodecenyl succinic anhydride, maleic anhydride and polybutadiene reaction, and maleic anhydride and styrene. Examples include polymers. Of these, a curing agent containing sulfone is particularly preferable.

The content of the curing agent is in the range in which the ratio (y) / (x) of the number of reactive functional groups (y) of the curing agent to the number of epoxy groups (x) of the epoxy resin is 0.3 or more and 1.5 or less. Is preferable, and the range of 0.5 or more and 1.2 or less is more preferable. When the ratio (y) / (x) is 0.3 or more, the reliability of the cured product can be improved, and when the ratio (y) / (x) is 1.5 or less, the strength of the cured product Can be improved.

Further, a curing accelerator can be blended to promote curing, and the curing accelerator of the epoxy resin includes imidazoles, triphenylphosphine or tetraphenylphosphine and salts thereof, amine compounds such as diazabicycloundecene, and the like. The salts and the like can be mentioned. For example, 2-methylimidazole, 2-ethylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2-phenyl-4,5-dihydroxymethyl. Imidazole compounds such as imidazole, 2-C11H23-imidazole, an adduct of 2-methylimidazole and 2,4-diamino-6-vinyltriazine are preferably used. Of these, an imidazole compound having a melting point of 180 ° C. or higher is particularly preferable. From the viewpoint of improving sinterability, imidazole containing no active hydrogen such as 1-benzyl-2-phenylimidazole, 1-benzyl-2-methylimidazole, 1,2-dimethylimidazole may be used.

The cyanate resin is a compound having a -NCO group in the molecule, and is a resin that is cured by forming a three-dimensional network structure by reacting the -NCO group by heating. Specifically, 1,3-disianatobenzene, 1,4-disyanatobenzene, 1,3,5-trisianatobenzene, 1,3-disianatonaphthalene, 1,4-disianatonaphthalene, 1, 6-disianatonaphthalene, 1,8-disianatonaphthalene, 2,6-disianatonaphthalene, 2,7-disianatonaphthalene, 1,3,6-trisianatonaphthalene, 4,4'-disyanatobiphenyl, bis (4-Cyanatophenyl) methane, bis (3,5-dimethyl-4-cyanatophenyl) methane, 2,2-bis (4-cyanatophenyl) propane, 2,2-bis (3,5-dibromo) -4-Cyanatophenyl) propane, bis (4-cyanatophenyl) ether, bis (4-cyanatophenyl) thioether, bis (4-cyanatophenyl) sulfone, tris (4-cyanatophenyl) phosphite, Examples thereof include tris (4-cyanatophenyl) phosphate and cyanates obtained by the reaction of novolak resin with cyanide halide. Further, a prepolymer having a triazine ring formed by trimerizing the cyanate group of these polyfunctional cyanate resins can also be used. The prepolymer is obtained by polymerizing the above-mentioned polyfunctional cyanate resin monomer using, for example, an acid such as mineral acid or Lewis acid, a base such as sodium alcoholate or tertiary amines, or a salt such as sodium carbonate as a catalyst. Be done.

As the curing accelerator for the cyanate resin, generally known ones can be used. Examples include organic metal complexes such as zinc octylate, tin octylate, cobalt naphthenate, zinc naphthenate, iron acetylacetone, metal salts such as aluminum chloride, tin chloride and zinc chloride, and amines such as triethylamine and dimethylbenzylamine. However, it is not limited to these. One type of these curing accelerators may be used, or two or more types may be mixed and used.

The maleimide resin is a compound containing one or more maleimide groups in one molecule, and is a resin that forms a three-dimensional network structure and is cured by reacting the maleimide groups by heating. For example, N, N'-(4,4'-diphenylmethane) bismaleimide, bis (3-ethyl-5-methyl-4-maleimidephenyl) methane, 2,2-bis [4- (4-maleimidephenoxy) phenyl. ] Bismaleimide resin such as propane can be mentioned. More preferable maleimide resins are compounds obtained by the reaction of diamine dimerate with maleic anhydride, and compounds obtained by the reaction of maleimided amino acids such as maleimide acetic acid and maleimide caproic acid with polyols. The maleimided amino acid is obtained by reacting maleic anhydride with aminoacetic acid or aminocaproic acid, and the polyol is preferably a polyether polyol, a polyester polyol, a polycarbonate polyol, or a poly (meth) acrylate polyol, and has an aromatic ring. Those that do not contain are particularly preferable.

The acrylic resin used here is a compound having a (meth) acryloyl group in the molecule, and is a resin that forms a three-dimensional network structure and is cured by the reaction of the (meth) acryloyl group. It is preferable that one or more (meth) acryloyl groups are contained in the molecule.
Examples of the acrylic resin include acrylic resins containing epoxy groups, amide groups, amino groups or hydroxyl groups, polyethers, polyesters, polycarbonates, and poly (meth) acrylates having (meth) acrylic groups. Examples of the epoxy group-containing acrylic resin include acrylic resins obtained by singly or copolymerizing allylallyl glycidyl ether, glycidyl methacrylate and the like. Examples of the amide group or amino-containing acrylic resin include acrylic resins obtained by singly or copolymerizing acrylamide, hydroxyethyl acrylamide, N-methylol acrylamide and the like. Examples of the carboxyl group-containing acrylic resin include acrylic resins obtained by singly or copolymerizing acrylic acid, methacrylic acid, itaconic acid and the like. As the hydroxyl group-containing acrylic resin, an acrylic resin obtained by using or copolymerizing hydroxyethyl acrylamide, hydroxyethyl acrylate, hydroxyethyl methacrylate, 4-hydroxybutyl acrylate, 1,4-cyclohexanedimethanol monoacrylate and the like can be used. Can be mentioned.
Preferred acrylic resins include polyethers having a molecular weight of 100 to 10,000, polyesters, polycarbonates, poly (meth) acrylates having a (meth) acrylic group, (meth) acrylates having a hydroxyl group, and (meth) having a hydroxyl group. Acrylamide, etc. can be mentioned.

The content of the thermosetting resin (B) is preferably 1 to 30 parts by mass, and more preferably 5 to 25 parts by mass with respect to 100 parts by mass of the (A) silver particles. When the content of (B) thermosetting resin is 1 part by mass or more, the adhesive effect of the thermosetting resin can be sufficiently obtained, and the content of (B) thermosetting resin is 30 parts by mass or less. It is possible to suppress a decrease in the proportion of the silver component, ensure high thermal conductivity sufficiently, and improve heat dissipation.

[(C) Binder resin]
The binder resin (C) can be used without particular limitation as long as it is a resin material for processing the resin composition into a sheet shape. Examples of the binder resin (C) include silicone oil, acrylic resin, phenoxy resin, nitrile rubber, and acrylic rubber. Of these, acrylic resin is preferable from the viewpoint of good sheet properties. One of these may be used, or two or more thereof may be mixed and used.

The weight average molecular weight (Mw) of the binder resin (C) is preferably 200,000 to 1,000,000, more preferably 400,000 to 800,000. (C) When the weight average molecular weight of the binder resin is 200,000 or more, the film forming property is improved, and when it is 1,000,000 or less, the viscosity of the formulation is suitable for coating.

The glass transition temperature (Tg) of the binder resin (C) is preferably −40 ° C. to 0 ° C., more preferably −30 ° C. to −5 ° C. (C) When the glass transition temperature of the binder resin is −40 ° C. or higher, the sheet surface is not tacked and the handleability is improved, and when it is 0 ° C. or lower, the film forming property is improved.
The glass transition temperature can be measured according to JIS K7121: 2012.

The content of the binder resin (C) is preferably 5 to 35 parts by mass, and more preferably 10 to 30 parts by mass with respect to 100 parts by mass of the (A) silver particles. When the content of the binder resin (C) is 5 parts by mass or more, a good sheet can be obtained, and when it is 35 parts by mass or less, a decrease in thermal conductivity can be suppressed.

The total content of the (B) thermosetting resin content and the (C) binder resin content is preferably 5 to 30% by mass, more preferably 5 to 30% by mass, based on the total amount of the resin composition. It is 6 to 25% by mass, more preferably 8 to 20% by mass. When the total content of the (B) thermosetting resin content and the (C) binder resin content is 5% by mass or more, the adhesive strength can be improved, and when it is 30% by mass or less, the heat is high. Conductivity can be maintained.

[Diluent]
The resin composition used in the present embodiment preferably further contains a diluent from the viewpoint of workability. Examples of the diluent include methyl ethyl ketone, toluene, butyl carbitol, cellosolve acetate, ethyl cellosolve, butyl cellosolve, butyl cellosolve acetate, butyl carbitol acetate, diethylene glycol dimethyl ether, diacetone alcohol, cyclohexanone, and N-methyl-2-pyrrolidone (NMP). , Dimethylformamide, N, N-dimethylacetamide (DMAc), γ-butyrolactone, 1,3-dimethyl-2-imidazolidinone, 3,5-dimethyl-1-adamantanamine (DMA) and the like. One of these may be used, or two or more thereof may be mixed and used.

When the resin composition used in the present embodiment contains a diluent, the content thereof is preferably 3 to 30 parts by mass, and more preferably 4 to 25 parts by mass with respect to 100 parts by mass of the silver particles (A). It is a part, more preferably 4 to 20 parts by mass. When the content of the diluent is 3 parts by mass or more, the viscosity can be reduced by dilution, and when it is 30 parts by mass or less, the solvent content remaining in the sheet is small, and voids when curing the resin composition. Is suppressed.

[Other ingredients]
In addition to the above components, the resin composition used in the present embodiment contains a coupling agent, an antifoaming agent, and a surfactant that are generally blended in this type of composition as long as the effects of the present invention are not impaired. , Colorants (pigments, dyes), various polymerization inhibitors, antioxidants, inorganic ion exchangers, and various other additives can be blended as needed. Each of these additives may be used alone or in combination of two or more.

Examples of the coupling agent include silane coupling agents such as epoxysilane, mercaptosilane, aminosilane, alkylsilane, cladesilane, vinylsilane, and sulfidesilane, titanate coupling agents, aluminum coupling agents, and aluminum / zirconium coupling agents. Can be mentioned.
Examples of the colorant include carbon black and the like.
Examples of the inorganic ion exchanger include hydrotalcite and the like.

The elastic modulus of the cured product of the resin composition is preferably 3 GPa or less, more preferably 2.8 GPa or less.
The glass transition temperature (Tg) of the cured product of the resin composition is preferably 0 ° C. or lower, more preferably −6 ° C. or lower.
The coefficient of thermal expansion of the cured product of the resin composition is preferably 50 ppm / ° C. or lower, more preferably 48 ppm / ° C. or lower at −50 to −40 ° C. and 140 ° C. to 150 ° C.
The elastic modulus, the glass transition temperature, and the coefficient of thermal expansion can all be measured by the methods described in the examples.

The thermal conductivity of the cured product obtained by curing the resin composition at 200 ° C. or lower is preferably 30 W / mK or more, and more preferably 32 W / mK or more.
The thermal conductivity can be measured by the method described in Examples.

The heat conductive adhesive sheet of the present embodiment is suitable as an adhesive sheet material useful for applications requiring thermal conductivity, particularly semiconductor bonding applications. In particular, good thermal conductivity is maintained even when the element generates heat.

<Manufacturing method of thermal conductive adhesive sheet>
As a method for producing a heat conductive adhesive sheet of the present embodiment, for example, (A) silver particles, (B) a thermosetting resin, and (C) a binder resin are mixed to obtain a resin composition. Examples thereof include a method of molding the resin composition into a sheet.
The heat conductive adhesive sheet of the present embodiment may be formed on the support film.

In the resin composition, (A) silver particles, (B) thermosetting resin, (C) binder resin, and various other components to be blended as needed are mixed by a disperse, a kneader, a rotation mixer, or the like. It can be prepared by mixing well.
The above-mentioned (A) epoxy resin, (B) thermosetting resin, (C) binder resin, and various other components to be blended as necessary are those described in the above section <Thermal Conductive Adhesive Sheet>. Can be used.

Next, the resin composition is applied onto a support film, dried, and formed into a sheet. Examples of the coating method include known methods such as a gravure coating method, a die coating method, a comma coating method, a lip coating method, a cap coating method, and a screen printing method. The drying temperature is preferably 70 ° C. to 120 ° C., more preferably 80 ° C. to 100 ° C. When the drying temperature is 70 ° C. or higher, the amount of solvent remaining in the sheet is small, the generation of voids when curing the resin composition is suppressed, and when the drying temperature is 120 ° C. or lower, the film forming property is high and handling becomes easy. .. Specific examples of the coating apparatus include μcoat 350 manufactured by Yasui Seiki Co., Ltd.

As the support film, a plastic film such as polyethylene, polypropylene, polyester, polycarbonate, polyarylate, or polyacrylonitrile having a release agent layer on one side is used.
From the viewpoint of handleability, the thickness of the support film is usually 10 to 50 μm, preferably 25 to 38 μm.

The thickness of the heat conductive adhesive sheet is preferably 10 to 100 μm, more preferably 10 to 50 μm. When the thickness of the heat conductive adhesive sheet is 10 μm or more, the handleability of the sheet is stable, and when it is 100 μm or less, the tack due to the residual solvent in the sheet can be reduced.

<Semiconductor device>
The semiconductor device of the present embodiment is supported by the support member, the cured product of the above-mentioned heat conductive adhesive sheet provided on the support member, and the cured product of the heat conductive adhesive sheet. It is characterized by having a semiconductor element bonded on a member.

In the semiconductor device of the present embodiment, for example, copper is temporarily attached to the joint surface of a silicon chip under the conditions of a temperature of 50 to 80 ° C., a pressure of 0.1 to 1 MPa, and a heating and pressurizing time of 0.1 to 1 minute. It is mounted on a support member such as a frame, and is heat-pressed and pressure-bonded under the conditions of a temperature of 80 ° C. to 200 ° C., a pressure of 0.1 to 5 MPa, and a heating and pressurizing time of 0.1 to 1 minute. It can be produced by heating and curing for 5 to 2 hours.

Examples of the support member include a copper frame, a metal substrate such as an aluminum or iron plate, a ceramic substrate, and a glass epoxy substrate.
Examples of semiconductor elements include ICs, LSIs, diodes, thyristors, transistors and the like.

Next, the present invention will be specifically described with reference to Examples, but the present invention is not limited to these examples.

(Manufacturing of silver particles)
[Synthesis Example 1]
40 g of silver nitrate was dissolved in 10 L of ion-exchanged water to prepare a silver nitrate aqueous solution, and 203 mL of ammonia water having a concentration of 26% by mass was added thereto and stirred to obtain a silver ammine complex aqueous solution. The temperature of this aqueous solution was set to 10 ° C., and 28 mL of a 20 mass% hydrazine monohydrate aqueous solution was added dropwise over 60 seconds with stirring to precipitate silver particles, thereby obtaining a silver particle-containing slurry. To this slurry, 1% by mass of oleic acid with respect to the amount of silver was added, and the mixture was stirred for 10 minutes. This slurry is filtered, the filter medium is washed with water and methanol, and dried in a vacuum atmosphere at 60 ° C. for 24 hours. The average particle size of the primary particles is 20 nm, the average particle size of the secondary particles is 1.1 μm, Silver particles having a tap density of 5.2 g / cm ³ and a specific surface area of 1.2 m ² / g were obtained.
When the cross section of the obtained silver particles was observed with a field emission scanning electron microscope (FE-SEM) (JSM-6700F manufactured by JEOL Ltd.), the silver particles were hollow particles having a void in the center. It was confirmed.

[Synthesis Example 2]
40 g of silver nitrate was dissolved in 10 L of ion-exchanged water to prepare a silver nitrate aqueous solution, and 203 mL of ammonia water having a concentration of 26% by mass was added thereto and stirred to obtain a silver ammine complex aqueous solution. The temperature of this aqueous solution was set to 10 ° C., and 18 mL of a 20 mass% hydrazine monohydrate aqueous solution was added dropwise over 60 seconds with stirring to precipitate silver particles, thereby obtaining a silver particle-containing slurry. To this slurry, 1% by mass of oleic acid with respect to the amount of silver was added, and the mixture was stirred for 10 minutes. This slurry is filtered, the filter medium is washed with water, washed with methanol, and dried in a vacuum atmosphere at 60 ° C. for 24 hours. The average particle size of the primary particles is 20 nm, the average particle size of the secondary particles is 1.5 μm, and the tap is used. Silver particles having a density of 5.4 g / cm ³ and a specific surface area of 1.1 m ² / g were obtained.

[Synthesis Example 3]
40 g of silver nitrate was dissolved in 10 L of ion-exchanged water to prepare a silver nitrate aqueous solution, and 203 mL of ammonia water having a concentration of 26% by mass was added thereto and stirred to obtain a silver ammine complex aqueous solution. The temperature of this aqueous solution was set to 10 ° C., and 12 mL of a 20 mass% hydrazine monohydrate aqueous solution was added dropwise over 60 seconds with stirring to precipitate silver particles, thereby obtaining a silver particle-containing slurry. To this slurry, 1% by mass of oleic acid with respect to the amount of silver was added, and the mixture was stirred for 10 minutes. This slurry is filtered, the filter medium is washed with water and methanol, and dried in a vacuum atmosphere at 60 ° C. for 24 hours. The average particle size of the primary particles is 20 nm, the average particle size of the secondary particles is 2.6 μm, Silver particles having a tap density of 5.0 g / cm ³ and a specific surface area of 1.0 m ² / g were obtained.

[Synthesis Example 4]
40 g of silver nitrate was dissolved in 10 L of ion-exchanged water to prepare a silver nitrate aqueous solution, and 203 mL of ammonia water having a concentration of 26% by mass was added thereto and stirred to obtain a silver ammine complex aqueous solution. 50 g of silver powder (product name: Ag-HWQ 1.5 μm, manufactured by Fukuda Metal Foil Powder Industry Co., Ltd.) was added to this aqueous solution to prepare a silver powder-dispersed silver ammine complex aqueous solution. The liquid temperature was set to 10 ° C., and 28 mL of a 20 mass% hydrazine monohydrate aqueous solution was added dropwise over 60 seconds with stirring to precipitate silver on the surface of the silver powder to obtain a silver particle-containing slurry. To this slurry, 1% by mass of oleic acid with respect to the amount of silver was added, and the mixture was stirred for 10 minutes. This slurry is filtered, the filter medium is washed with water, washed with methanol, and dried in a vacuum atmosphere at 60 ° C. for 24 hours. The average particle size of the primary particles is 20 nm, the average particle size of the secondary particles is 1.9 μm, and the tap is used. Silver particles having a density of 5.7 g / cm ³ and a specific surface area of 1.0 m ² / g were obtained.
When the cross section of the obtained silver particles was observed with a field emission scanning electron microscope (FE-SEM) (JSM-6700F manufactured by JEOL Ltd.), the silver particles had silver aggregated around the silver powder and were particles. It was confirmed that the particles were solid particles with virtually no space inside.

The silver particles obtained in Synthesis Examples 1 to 4 were evaluated by the following methods.
[Average particle size of primary particles]
To measure the average particle size of the primary particles, 2.8 mL of a 20 mass% hydrazine monohydrate aqueous solution was added dropwise to 1020 mL of the silver ammine complex aqueous solution obtained in each of the above synthetic examples over 60 seconds for solid-liquid separation. Then, the obtained solid substance was washed with pure water and dried in a vacuum atmosphere at 60 ° C. for 24 hours to use the obtained silver particles.
The average particle size of the primary particles is the field emission scanning electron microscope (FE-SEM) (manufactured by JEOL), which is a cross section of spherical silver particles cut with a focused ion beam (FIB) device (JEM-9310FIB manufactured by JEOL). It was determined by averaging the particle diameters of 200 silver particles measured by observing with JSM-6700F).

[Average particle size of secondary particles]
The average particle size of the secondary particles is the particle size (50) at which the integrated volume is 50% in the particle size distribution measured using a laser diffraction type particle size distribution measuring device (manufactured by Shimadzu Corporation, trade name: SALAD-7500 nano). % Particle size D50).

[Coefficient of thermal expansion]
For the silver particles, a cylindrical pellet type sample having a diameter of 5 mm and a thickness of 1 mm was obtained by applying a load of 200 kgf to the silver particles for 1 minute using a mini hydraulic press (manufactured by Specac). The sample is heated from room temperature to 350 ° C at a heating rate of 20 ° C / min using a thermomechanical analysis (TMA) device (manufactured by Seiko Instruments Co., Ltd., trade name: TMA SS150). The coefficient of thermal expansion was measured and the coefficient of thermal expansion was obtained when the pellet length was 25 ° C., and the maximum coefficient of thermal expansion in the firing temperature range of 150 ° C. to 300 ° C. was defined as the maximum coefficient of thermal expansion.

[Tap density]
^{The tap density (TD) was measured as a mass per unit volume (unit: g / cm 3} ) of silver particles in a vibrated container with a tap density measuring device (Tap-Pak Volumeter, manufactured by Thermo Scientific). ..

[Specific surface area]
The specific surface area was measured by the BET one-point method by nitrogen adsorption using a specific surface area measuring device (Monosorb, manufactured by Quanta Chrome) after degassing at 60 ° C. for 10 minutes.

(Examples 1 to 8 and Comparative Examples 1 to 7)
(1) Preparation of resin composition Each component of the type and blending amount shown in Table 1 is mixed at 25 ° C. using a self-revolving mixer (manufactured by Shinky Co., Ltd., model number: ARV-310) to prepare a resin composition. Prepared.
In Table 1, blanks indicate no compounding.

(2) Preparation of Thermally Conductive Adhesive Sheet Using μcoat 350 manufactured by Yasui Seiki Co., Ltd., the above resin composition was used as a release film (manufactured by Toyobo Co., Ltd., trade name: TN-200, thickness). A heat conductive adhesive sheet having a thickness of 20 μm was formed by a gravure coating method while supplying the film on one of the release surfaces (25 μm). The drying conditions were a temperature of 80 ° C. and a speed of 1 m / min.

Details of each component shown in Table 1 used for preparing the resin composition are as follows.

[(A) Silver particles]
(A1): Silver particles obtained in Synthesis Example 1 (average particle size of primary particles: 20 nm, average particle size of secondary particles: 1.1 μm, maximum coefficient of thermal expansion: +5.5 ppm / ° C., tap density: 5.2 g / cm ³ , specific surface area: 1.2 m ² / g)
(A2): Silver particles obtained in Synthesis Example 2 (average particle size of primary particles: 20 nm, average particle size of secondary particles: 1.5 μm, maximum coefficient of thermal expansion: + 7.4 ppm / ° C., tap density 5). .4 g / cm ³ , specific surface area: 1.1 m ² / g)
(A3): Silver particles obtained in Synthesis Example 3 (average particle size of primary particles: 20 nm, average particle size of secondary particles: 2.6 μm, maximum coefficient of thermal expansion: +7.0 ppm / ° C., tap density: 5.0 g / cm ³ , specific surface area: 1.0 m ² / g,)
(A4): Silver particles obtained in Synthesis Example 4 (average particle size of primary particles: 20 nm, average particle size of secondary particles: 1.9 μm, maximum coefficient of thermal expansion: + 2.5 ppm / ° C., tap density: 5.7 g / cm ³ , specific surface area: 1.0 m ² / g)

[Silver particles other than component (A)]
-TC-505C (manufactured by Tokuriki Honten Co., Ltd., trade name, average particle size: 1.93 μm, maximum coefficient of thermal expansion: -0.1 ppm / ° C, tap density: 6.25 g / cm ³ , specific surface area: 0. 65m ² / g)
-Ag-HWQ 1.5 μm (manufactured by Fukuda Metal Foil Powder Industry Co., Ltd., trade name, average particle size: 1.8 μm, maximum coefficient of thermal expansion: -0.6 ppm / ° C, tap density: 3.23 g / cm ³ , Specific surface area: 0.5m ² / g)
-AgC-221PA (manufactured by Fukuda Metal Foil Powder Industry Co., Ltd., trade name, average particle size: 7.5 μm, maximum coefficient of thermal expansion: -0.1 ppm / ° C, tap density: 5.7 g / cm ³ , specific surface area : 0.3m ² / g)
-DOWA Ag nano powder-1 (manufactured by DOWA Electronics Co., Ltd., trade name, average particle size: 20 nm, maximum coefficient of thermal expansion: -0.1 ppm / ° C.)

[(B) Thermosetting resin]
-Epoxy resin (manufactured by Mitsubishi Chemical Corporation, trade name, YX7105, liquid (viscosity at 25 ° C.: 45,000 mPa · s))
-Epoxy resin (manufactured by Mitsubishi Chemical Corporation, trade name, jER1001, solid (softening point 65 ° C))
-Epoxy resin (manufactured by Mitsubishi Chemical Corporation, trade name, jER1009, solid (softening point 140 ° C))
-Acrylic resin: Hydroxyethyl acrylamide (manufactured by KJ Chemicals Co., Ltd., HEAA (registered trademark))
-Curing agent: Diaminodiphenyl sulfone (manufactured by Mitsui Kagaku Fine Co., Ltd., trade name, 4,4-DAS)

[(C) Binder resin]
・ Acrylic binder (manufactured by Nippon Carbide Industries, Ltd., trade name, Nisetsu, weight average molecular weight 500,000, glass transition temperature -10 ° C)
・ Acrylic binder (manufactured by Nippon Carbide Industries, Ltd., trade name, Nisetsu, weight average molecular weight 100,000, glass transition temperature 0 ° C)

[Diluent]
・ Methyl ethyl ketone (manufactured by Sankyo Chemical Co., Ltd.)

[Other ingredients]
-Curing accelerator: Imidazole type (manufactured by Shikoku Chemicals Corporation, trade name, Curesol 2P4MHZ-PW)
-Curing agent: Dicumyl peroxide (NOF CORPORATION, trade name, Park Mill (registered trademark) D)

An adhesive sheet (hereinafter, also simply referred to as an adhesive sheet) in which a heat conductive adhesive sheet is formed on one side of the release films obtained in Examples 1 to 7 and Comparative Examples 1 to 5 under the measurement conditions shown below. The properties of the heat conductive adhesive sheet were measured and evaluated. The evaluation results are shown in Table 1.

<Evaluation items>
(1) Sheet properties The adhesive sheet was bent 180 degrees, visually observed, and evaluated according to the following criteria.
〇: The heat conductive adhesive sheets of the bent adhesive sheet did not adhere to each other and there was no crack in the bent part. ×: The thermal conductive adhesive sheets of the bent adhesive sheet adhered to each other or at the bent part. Crack occurred

(2) Temporary Adhesiveness On a 6 mm x 6 mm silicon chip and a back gold chip with a gold-deposited layer on the joint surface, the surface of the adhesive sheet on the heat conductive adhesive sheet side is set at 65 ° C. for 1 second and the pressure is 1 MPa. When crimped with, the case where it can be pasted was judged as ◯, and the case where it could not be pasted was judged as x.

(3) Elastic modulus The thermal conductivity adhesive sheet was cured at 200 ° C. for 2 hours, cut into a size of 55 cm in length × 1 cm in width × 20 μm in thickness to prepare a sample, and the sample was used as a thermomechanical analyzer (Seiko Instruments (Seiko Instruments). The elastic modulus was measured at 25 ° C. by raising the temperature from −50 ° C. to 300 ° C. at 10 ° C. per minute with an apparatus name: DMA) manufactured by Co., Ltd.

(4) Glass transition temperature (Tg)
The heat conductive adhesive sheet was cured at 200 ° C. for 2 hours, and a sample was cut out to a size of 55 cm in length × 1 cm in width × 20 μm in thickness, and the sample was used as a thermomechanical analyzer (manufactured by Seiko Instruments Inc.). The glass transition temperature was measured by raising the temperature from −50 ° C. to 300 ° C. by 10 ° C. per minute with a name: DMA).

(5) Coefficient of thermal expansion The coefficient of thermal expansion was cured at 200 ° C. for 2 hours, and a sample was cut out to a size of 3 cm in length × 0.5 cm in width × 20 μm in thickness, and the sample was used as a thermomechanical analyzer (Seiko). Instrument Co., Ltd., device name: TMA / SS) raises the temperature from -50 ° C to 200 ° C by 10 ° C per minute to sample samples between -50 ° C and -40 ° C and between 140 ° C and 150 ° C. The amount of deformation was measured as a coefficient of thermal expansion.

(6) Thermal conductivity (cured at 200 ° C)
The heat conductive adhesive sheet was cured at 200 ° C. for 2 hours, and a sample was cut out to a size of 1 cm in length × 1 cm in width × 20 μm in thickness to prepare a sample. The thermal conductivity of the sample was measured by a laser flash method using a thermal conductivity meter (manufactured by Advance Riko Co., Ltd., device name: TC7000) according to JIS R 1611: 1997.
In addition, the thermal conductivity of 30 W / m · K or more was regarded as acceptable.

(7) Thermal conductivity (cured at 300 ° C)
The heat conductive adhesive sheet was cured at 300 ° C. for 2 hours, and a sample was cut out to a size of 1 cm in length × 1 cm in width × 20 μm in thickness to prepare a sample. The thermal conductivity of the sample was measured by a laser flash method using a thermal conductivity meter (manufactured by Advance Riko Co., Ltd., device name: TC7000) according to JIS R 1611: 1997.
In addition, the thermal conductivity of 150 W / m · K or more was regarded as acceptable.

(8) Thermal Adhesive Strength 6 mm x 6 mm silicon chip and back gold chip with gold vapor deposition layer on the joint surface, the surface of the adhesive sheet on the heat conductive adhesive sheet side is 65 ° C. for 1 second, pressure 1 MPa After temporarily attaching under the conditions, the release film of the adhesive sheet is peeled off, and the surface of the heat conductive adhesive sheet opposite to the surface to which the gold chip is temporarily attached is mounted on a solid copper frame at 125 ° C. A sample was prepared by heat-pressing and pressure-bonding at a pressure of 0.1 MPa for 5 seconds and further curing in an oven at 180 ° C. for 1 hour. Using a mount strength measuring device (manufactured by Besi, device name: 2200 EVO-plus), the thermal die shear strength of the above sample at 260 ° C. was measured.

(9) Reliability test (cold heat cycle)
The sample prepared in (8) was heated in a thermal cycle tester from -55 ° C to 150 ° C, and then cooled to -55 ° C as one cycle, which was tested for 1000 cycles and was defective. The incidence of (poor peeling) was investigated (number of samples = 20).

(A) Examples 1 to 8 using a heat conductive adhesive sheet obtained by molding a resin composition containing silver particles into a sheet have excellent temporary adhesiveness and sheet property, and are baked at a low temperature of 200 ° C. or lower. It is possible to obtain a semiconductor device having high thermal conductivity and excellent reliability even under the binding conditions.

Claims (12)

A heat conductive adhesive sheet obtained by molding a resin composition containing (A) silver particles, (B) a thermosetting resin, and (C) a binder resin into a sheet shape.
The silver particles (A) are heat conductive adhesive sheets, which are secondary particles in which particles including primary particles having an average particle diameter of 10 to 100 nm are aggregated. The heat conductive adhesive sheet according to claim 1, wherein the silver particles (A) have a positive coefficient of thermal expansion between 150 ° C. and 300 ° C. The heat conductive adhesive sheet according to claim 1 or 2, wherein the silver particles (A) have a tap density of 4.0 to 7.0 g / cm ^3. The heat conductive adhesive sheet according to any one of claims 1 to 3, wherein the silver particles (A) have a specific surface area of 0.5 to 1.5 m ^{2 / g determined by the BET method.} The heat conductive adhesive sheet according to any one of claims 1 to 4, wherein the silver particles (A) have an average particle size of 0.5 to 5.0 μm. The heat conductive adhesive sheet according to any one of claims 1 to 5, wherein the thermosetting resin (B) is a liquid or a solid material having a softening point of 70 ° C. or lower. The thermosetting adhesive sheet according to any one of claims 1 to 6, wherein the thermosetting resin (B) is at least one selected from the group consisting of an epoxy resin, a cyanate resin, a maleimide resin, and an acrylic resin. The thermal conductivity according to any one of claims 1 to 7, wherein the binder resin (C) has a weight average molecular weight of 200,000 to 1,000,000 and a glass transition temperature of −40 ° C. to 0 ° C. Adhesive sheet. The total content of the (B) thermosetting resin content and the (C) binder resin content is 5 to 30% by mass with respect to the total amount of the resin composition, and the (A) silver particles. The thermosetting adhesive sheet according to any one of claims 1 to 8, wherein the content of the resin is 30 to 95% by mass. After curing of the resin composition, the elastic modulus is 3 GPa or less, the glass transition temperature (Tg) is 0 ° C. or less, and the thermal expansion coefficient is 50 ppm / ° C. at −50 to −40 ° C. and 140 ° C. to 150 ° C. The heat conductive adhesive sheet according to any one of 1 to 9 below. The heat conductive adhesive sheet according to any one of claims 1 to 10, wherein the cured product obtained by curing the resin composition at 200 ° C. or lower has a thermal conductivity of 30 W / m · K or more. The support member, a cured product of the heat conductive adhesive sheet according to any one of claims 1 to 11 provided on the support member, and a cured product of the heat conductive adhesive sheet are used. A semiconductor device characterized by having a semiconductor element bonded on a support member.