JP7031203B2 - Adhesive sheet for heat dissipation, laminate for heat dissipation adhesive member, and composite member - Google Patents

Description

The present invention relates to a heat-dissipating adhesive sheet, a laminated body for heat-dissipating adhesive members, and a composite member using the heat-dissipating adhesive sheet, and more particularly to a composite member suitable for a power semiconductor device.

Power semiconductor modules are installed in electric power drive equipment such as home appliances, industrial robots, and transportation equipment. Power semiconductor devices can be driven even under high current and voltage, but on the other hand, power loss causes heat generation and the module is exposed to a high temperature environment, so the power semiconductor module has an efficient heat dissipation structure. Is indispensable. For this reason, in general, a heat dissipation base substrate represented by a heat sink is connected to a power semiconductor module via an adhesive sheet which is an insulator such as resin.

In order to increase the heat dissipation efficiency, it is essential to increase the thermal conductivity of the connecting member such as the resin. For example, thermally conductive ceramic particles such as alumina, boron nitride, aluminum nitride and silicon nitride are dispersed in the resin. A method of using a heat-dissipating adhesive sheet is known.
For example, Patent Document 1 describes a power semiconductor device including a heat dissipation base substrate, a semiconductor module in which a metal plate, a solder layer, and a semiconductor chip are laminated in this order, and the metal plate and the heat dissipation base substrate. A power semiconductor device in which a cured body of an epoxy resin composition containing an epoxy resin, a novolak resin curing agent, α-alumina, boron nitride and the like is arranged is disclosed.

Japanese Unexamined Patent Publication No. 2016-155985

As disclosed in Patent Document 1, the epoxy resin composition in a semi-cured state is sandwiched between the semiconductor module and the heat radiating member to improve the adhesiveness, and after the sandwiching, the epoxy resin composition is cured through a pressurizing / heating step. By making it, a strong adhesive force is expressed. However, during this pressurization / heating, exudation or exudation may occur, resulting in poor workability and defective products.
Further, there is a problem that cracks are likely to occur inside the cured body due to stress generated by expansion and contraction of the semiconductor module and the heat radiating member due to a sudden temperature change, and the thermal conductivity is significantly deteriorated.

The present invention is a heat-dissipating adhesive sheet having high heat dissipation and excellent durability against heat fatigue, by using a heat-dissipating adhesive member laminate having the heat-dissipating adhesive sheet and a heat-dissipating adhesive sheet. It is an object of the present invention to provide a composite member having not only heat dissipation but also no protrusion or exudation and good durability. Among them, the yield of the manufacturing process of the power semiconductor device is good, and the durability is also good in the thermal cycle. Therefore, the adhesive sheet for heat dissipation suitable for the power semiconductor device, and the durability and heat dissipation efficiency for the thermal cycle are It is an object of the present invention to provide a high composite member.

In order to solve the above problems, the heat-dissipating adhesive sheet is characterized by containing a thermosetting resin (A) and dendrite-like metal fine particles (B).

The heat-dissipating adhesive sheet of the present invention has voids and the like due to the dendrite-like metal fine particles (B), so that the thermosetting resin flows during the heat press and can be filled in the voids and the like. As a result, it is possible to suppress the lateral flow of the heat-dissipating adhesive sheet and improve the problems of protrusion and exudation workability. As a result, in the power semiconductor device using the heat-dissipating adhesive sheet, the number of defective products derived from protrusion is significantly reduced, and the yield is improved. Furthermore, due to the three-dimensional shape derived from the dendrite-like metal fine particles (B), it is possible to maintain a high level of thermal conductivity even if stress strain is generated during the thermal cycle test.

Therefore, according to the present invention, the present invention provides a heat-dissipating adhesive sheet having excellent heat-dissipating properties, which can minimize the protrusion and exudation of the heat-dissipating adhesive sheet during a heating press during the manufacture of a power semiconductor device, and has good workability. be able to. By using the heat-dissipating adhesive laminated body having the heat-dissipating adhesive sheet, it is possible to provide a composite member having not only heat dissipation but also no protrusion or exudation and good durability. In addition, the composite member using the laminated body for the heat-dissipating adhesive member can maintain high durability and heat-dissipating properties and ensure good operation even in a harsh environment where cold heat is repeated.

It is sectional drawing which shows an example of the laminated body for a heat dissipation adhesive member of this invention. It is sectional drawing which shows an example of the composite member of this invention.

<< Adhesive sheet for heat dissipation >>
The heat-dissipating adhesive sheet of the present invention is for adhering a heating element including a member capable of generating heat and a heat-dissipating base substrate for dissipating heat generated from the heating element including a member capable of generating heat. An adhesive sheet for forming a laminate for a heat-dissipating adhesive member, which contains at least a thermosetting resin (A) and dendrite-like metal fine particles (B). The heat-dissipating adhesive sheet is used for forming a heat-dissipating layer by a heating press and adhering to at least one of a heating element including a member capable of generating heat and a heat-dissipating base substrate. The heat-dissipating adhesive sheet may be a single layer or a plurality of laminated sheets.

The thickness of the heat-dissipating adhesive sheet of the present invention is preferably 5 to 100 μm, more preferably 6 to 50 μm.

Further, in the heat-dissipating adhesive sheet of the present invention, the thickness (II) of the heat-dissipating adhesive sheet after heat-pressing under the conditions of 150 ° C., 2 MPa and 30 minutes was set to 100 as the thickness (I) before heat-pressing. Sometimes it is preferably 30-95. The thickness (II) after the heating press is more preferably 60 to 80. When the thickness (II) after the heat press is smaller than 95, sufficient voids are secured in the heat radiating layer, so that it is possible to reduce the seepage of the thermosetting resin (A) in the horizontal direction during the heat press. On the other hand, when the thickness (II) after the heating press is higher than 30, the voids can be completely filled by the heating press, so that the desired heat dissipation can be achieved.

The thickness (II) of the heat-dissipating adhesive sheet after heat pressing is preferably 5 to 30 μm, more preferably 8 to 20 μm. By making the above thickness, heat dissipation and durability can be improved.

The heat-dissipating adhesive sheet of the present invention can be filled with the thermosetting resin (A) by heat-pressing the voids formed by the dendrite-like metal fine particles (B). Compared with the case where a heat-dissipating adhesive sheet using spherical or flake-shaped metal fine particles is heat-pressed under the same conditions, lateral exudation can be reduced.
Generally, the heating press is performed under the conditions of a temperature of about 150 to 190 ° C., a pressure of about 1 to 3 MPa, and a time of about 1 to 60 minutes.
Further, the thickness of the heat-dissipating adhesive sheet after heat pressing, that is, when the heat-dissipating layer is formed, is preferably 5 to 30 μm, more preferably 8 to 20 μm. By making the above thickness, heat dissipation and durability can be improved.

<Thermosetting resin (A)>
In the present invention, as the thermosetting resin (A), a known thermosetting resin can be used, and it is preferable to use a binder resin that is softened by heat. The Tg of the thermosetting resin is preferably −20 ° C. or higher and 100 ° C. or lower, and more preferably −10 ° C. or higher and 80 ° C. or lower. As the thermosetting resin, one type may be used or a plurality of types may be used in combination. When a plurality of types are used, it is preferable that the main component is one in which Tg before mixing is included in the above range. The thermosetting resin is not particularly limited as long as it has a flow property that softens during thermocompression bonding and fills the voids of the dendrite-like metal particles.

Among the thermosetting resins, phenol-based, epoxy-based, urethane-based, melamine-based, alkyd-based, and amide-based resins are preferable. Furthermore, considering that it is used by being exposed to a sudden temperature change after being adhered in a heat pressing process like a power semiconductor device and then affixed, urethane-based resin and amide-based resin having both adhesion and durability are considered. Is more preferable.

The thermosetting resin is a resin having a plurality of functional groups that can be used for a crosslinking reaction by heating.
Examples of the functional group include a hydroxyl group, a phenolic hydroxyl group, a carboxyl group, an amino group, an epoxy group, an oxetanyl group, an oxazoline group, an oxazine group, an aziridine group, a thiol group, an isocyanate group, a blocked isocyanate group and a silanol group. ..

The weight average molecular weight of the thermosetting resin (A) is preferably 2,000 to 120,000, more preferably 25,000 to 100,000. When the weight average molecular weight is 20,000 to 120,000, both durability and fluidity can be achieved at a high level.

As the curing agent that can be used in combination with the thermosetting resin (A), a known compound corresponding to the functional group of the thermosetting resin can be used. For example, when the resin contains a carboxyl group, an epoxy curing agent or the like is preferable. When the resin contains a hydroxyl group, an isocyanate curing agent, an acid anhydride group-containing compound, or the like is preferable.

In the present invention, in addition to the thermosetting resin (A), a thermoplastic resin can be used in combination.
Examples of the thermoplastic resin include polyolefin resins, vinyl resins, styrene / acrylic resins, diene resins, terpene resins, petroleum resins, cellulose resins, polyamide resins, polyurethane resins, and polyester resins that do not have the curable functional group. , Polycarbonate resin, polyimide resin, fluororesin and the like.
The polyolefin resin is preferably a homopolymer or copolymer such as ethylene, propylene or α-olefin compound. Specific examples thereof include polyethylene propylene rubber, olefin-based thermoplastic elastomers, α-olefin polymers and the like.
As the vinyl resin, a polymer obtained by polymerizing a vinyl ester such as vinyl acetate and a copolymer of a vinyl ester and an olefin compound such as ethylene are preferable. Specific examples thereof include ethylene-vinyl acetate copolymers and partially saponified polyvinyl alcohols.
The styrene / acrylic resin is preferably a homopolymer or a copolymer composed of styrene, (meth) acrylonitrile, acrylamides, (meth) acrylic acid esters, maleimides and the like. Specific examples thereof include syndiotactic polystyrene, polyacrylonitrile, acrylic copolymers, ethylene-methyl methacrylate copolymers and the like.
The diene-based resin is preferably a homopolymer or copolymer of a conjugated diene compound such as butadiene or isoprene, and hydrogenated additives thereof. Specific examples thereof include styrene-butadiene rubber and styrene-isoprene block copolymers. The terpene resin is preferably a polymer composed of terpenes or a hydrogenated product thereof. Specific examples thereof include aromatic-modified terpene resin, terpene phenol resin, and hydrogenated terpene resin.
As the petroleum-based resin, dicyclopentadiene type petroleum resin and hydrogenated petroleum resin are preferable. The cellulose-based resin is preferably a cellulose acetate butyrate resin. The polycarbonate resin is preferably bisphenol A polycarbonate. As the polyimide resin, a thermoplastic polyimide, a polyamide-imide resin, and a polyamic acid type polyimide resin are preferable.

<Dendrite-like metal fine particles (B)>
In the present invention, the dendrite-like shape of the dendrite-like metal fine particles (B) is generally also referred to as a dendritic shape, and means a shape like a tree branch. The material of the dendrite-like metal fine particles (B) is a heat-dissipating metal such as gold, silver, copper, nickel, zinc or iron or an alloy thereof, a heat-dissipating organic compound such as polyaniline or polystyrene, or a heat-dissipating compound obtained by combining these. Can be used. Alternatively, it is also preferable to use metal fine particles having a metal or an organic compound as a nucleus and the surface of the nucleus coated with a heat-dissipating material.

The metal fine particles having a heat-dissipating coating layer are composed of a metal alloy such as copper, nickel, or cadmium, a heat-dissipating organic compound such as polyaniline or polystyrene, or a normal non-heat-dissipating organic compound as a core, and the surface coating layer. Is preferably coated with a metal having excellent heat dissipation such as gold, silver, and copper. Further, metal fine particles having copper as a core and a coating layer formed of silver are more preferable.

The proportion of the heat-dissipating coating layer in the metal fine particles having a coating layer is preferably 1% by weight to 40% by weight, more preferably 5% by weight to 20% by weight, based on 100% by weight of the dendrite-like conductive fine particles (B). By using the metal fine particles coated with silver, it is possible to suppress the cost reduction due to the reduction in the amount of expensive silver used and the decrease in heat dissipation due to the oxidation of copper when the conductive fine particles of copper are used.

That is, the dendrite-like metal fine particles (B) have a copper core and a silver-coated layer on the surface thereof, and the silver-coated layer is 1 to 40% by weight in 100% by weight of the dendrite-like metal fine particles (B). Is preferable from the viewpoint of cost reduction and heat dissipation.

In the present invention, the thickness of the heat-dissipating adhesive sheet changes before and after the heat press because voids are likely to exist in the adhesive sheet mainly due to the presence of bulky dendrite-like metal fine particles (B). It is presumed that this is because A) flows and fills the void. This void is more susceptible to the relationship between the average particle diameters D ₅₀ and D ₉₀ of the dendrite-like metal fine particles (B) used. The more voids there are in the adhesive sheet before the heating press, the greater the change in thickness. That is, when the thickness before pressing is 100, it is considered that the smaller the value of the thickness after pressing, the more voids are in the adhesive sheet.

That is, in the present invention, the dendrite-like metal fine particles (B) have an average particle diameter D ₅₀ of more preferably 3 to 50 μm, and even more preferably 5 to 25 μm. When the average particle diameter D ₅₀ is 3 μm or more, voids are likely to be formed in the adhesive sheet, and exudation can be reduced. On the other hand, when the average particle diameter D ₅₀ is 50 μm or less, the heat dissipation layer can be thinned and the heat dissipation property can be achieved after the heat-dissipating adhesive sheet is heat-pressed.

The average particle size D ₉₀ of the dendrite-like metal fine particles (B) is preferably 1.5 to 5 times, more preferably 2 to 3.5 times that of D ₅₀ . The value of the average particle diameter D ₉₀ tends to depend on the average particle diameter of D ₅₀ , but is preferably 4.5 μm to 250 μm. When the average particle size D ₉₀ is 1.5 times or more that of D ₅₀ , the width of the particle size distribution is widened, so that voids tend to occur in the heat radiation layer. On the other hand, when the average particle size D ₉₀ is 5 times or less of D ₅₀ , the width of the particle size distribution does not widen too much, and the filling of the dendrite-like metal fine particles (B) in the adhesive sheet tends to be appropriate. .. Further, the presence of the huge dendrite-like particles makes it difficult for the huge dendrite-like particles to protrude from the heat dissipation layer after the heating press.
Therefore, it is preferable that the average particle diameter D ₅₀ is 3 to 50 μm and the average particle diameter D ₉₀ is 1.5 to 5 times that of D ₅₀ .

The average particle diameters D ₅₀ and D ₉₀ of the dendrite-like metal fine particles can be measured using Microtrac MT3300 manufactured by Nikkiso Co., Ltd.
Here, the average particle size D ₅₀ is a particle size that becomes 50% when the volume ratio of the particles is integrated from the fine particle size distribution in the volume particle size distribution, and the average particle size D ₉₀ is a particle size where 90% is reached. The average particle size D ₅₀ and D ₉₀ of the dendrite-like metal fine particles are measured by a general particle size distribution meter, for example, a laser scattering type particle size distribution meter (“Microtrack MT3300EXII” manufactured by Nikkiso Co., Ltd.). The volume average particle size can be measured by the laser scattering method as follows. A slurry is prepared by mixing dendrite-like metal fine particles and water. Inject the diluted slurry into the cell of the measuring device [Nikkiso Co., Ltd. Microtrack MT3300EXII] until the concentration becomes appropriate in sampling loading, input the refractive index condition of the solvent (water in the present invention) according to the sample, and then measure. I do.

In the present invention, the dendrite-like metal fine particles (B) preferably have a tap density (hereinafter, also referred to as TD) of 0.8 to 2.5 g / cm ³ . When the TD is 0.8 g / cm ³ or more, the metal fine particles in the adhesive sheet can be filled more densely. On the other hand, when the TD is 2.5 g / cm ³ or less, the metal fine particles in the adhesive sheet are less likely to be overcrowded, and the film thickness change before and after the heating press tends to be large. The output can be further reduced.

Further, the dendrite-like metal fine particles (B) preferably have an apparent density (hereinafter, also referred to as AD) of 0.4 to 1.5 g / cm ³ . When the AD is 0.4 g / cm ³ or more, the metal fine particles in the adhesive sheet can be filled more densely. On the other hand, when the TD is 1.5 g / cm ³ or less, the metal fine particles in the adhesive sheet are less likely to be overcrowded, and the film thickness change before and after the heating press tends to be large. The output can be further reduced.

The apparent density of the dendrite-like metal fine particles can be obtained by the apparent density test method of the metal powder specified in JIS Z 2504: 2000, and the tap density can be obtained by the JIS Z 2512: metal powder-tap density measuring method. can.

Since the dendrite-like metal fine particles (B) have a shape like a tree branch as compared with the spherical or flake-shaped metal fine particles, gaps are likely to occur between the individual particles. Therefore, when the heat-dissipating adhesive sheet is formed by using the dendrite-like metal fine particles (B), voids are likely to occur.

Then, by making the values of the apparent density and the tap density of the dendrite-like metal fine particles (B) appropriate, it is possible to more appropriately form voids in the heat-dissipating adhesive sheet. That is, in the present invention, the dendrite-like metal fine particles (B) preferably have an AD to TD ratio (AD / TD) of 0.3 to 0.9. When the AD / TD is 0.3 or more, the values of AD and TD become more appropriate, and the film thickness change after the heating press tends not to be too large. On the other hand, when the AD / TD is 0.9 or less, the numerical values of AD and TD become more appropriate, and the film thickness change after the heating press tends not to be too small.

The ratio of using the dendrite-like metal fine particles (B) in the heat-dissipating adhesive sheet is preferably 50 to 90% by weight, more preferably 60 to 80% by weight, based on 100% by weight of the heat-dissipating adhesive sheet. When the amount used is 50% by weight or more, the desired heat dissipation tends to be easily obtained. On the other hand, when it is 90% by weight or less, it is easy to secure the amount of resin for forming a sheet, and there is a tendency that the coating suitability can be improved.

In the present invention, the heat-dissipating adhesive sheet includes a thermosetting resin (A) and dendrite-like metal fine particles (B), as well as a silane coupling agent, an antioxidant, a pigment, a dye, a tackifier resin, and a plasticizer, if necessary. It can also contain agents, UV absorbers, antifoaming agents, leveling modifiers, fillers, flame retardants and the like.

Subsequently, a method for manufacturing the heat-dissipating adhesive sheet of the present invention will be described. First, at least the thermosetting resin (A) and the dendrite-like metal fine particles (B) are mixed to prepare a heat-dissipating resin composition.

As a mixing method, for example, it is preferable to use a mixer, a solver, a Hoover Marler, a three-roll mill, a sand mill, or the like.

Using this heat-dissipating resin composition, conventionally known coating methods such as gravure coat method, kiss coat method, die coat method, lip coat method, comma coat method, blade coat method, roll coat method, knife coat method, spray coat An adhesive sheet for heat dissipation can be formed by a method, a bar coat method, a spin coat method, a dip coat method, or the like.

The thickness of the heat-dissipating adhesive sheet is preferably 5 to 100 μm. The thickness is a value measured according to JISB7503 (dial gauge).

The film thickness of the heat-dissipating adhesive sheet of the present invention after heat pressing is preferably 0.25 to 10 times, preferably 0.5 to 5 times, the average particle diameter _D50 of the dendrite-like metal fine particles (B). Is more preferable.

As described above, the heat-dissipating adhesive sheet of the present invention of the present invention has a low yield and good thermal conductivity and durability. Therefore, in addition to electronic devices such as home appliances, industrial robots, and transportation devices, power semiconductor modules, and building materials. , Vehicles, aircraft, and ships.

<< Laminated body for heat-dissipating adhesive member >>
The heat-dissipating adhesive member laminate is a laminate arranged between a heat-dissipating base substrate and a heating element including a member that can generate heat, and includes the heat-dissipating base substrate and a member that can generate heat. It has at least an insulating layer and a heat-dissipating adhesive sheet that adheres to at least one of the bodies. Further, a heat radiating adhesive member is formed by arranging it between a heat radiating base substrate and a heating element including a member capable of generating heat and heating and pressing it.

As the insulating layer, for example, an insulating heat conductive ceramic plate, an insulating adhesive sheet, an insulating film or the like can be used.

The heat conductive ceramic plate is mainly composed of the heat curable resin and a heat conductive ceramic such as alumina (Al ₂ O ₃ ), boron nitride (BN), aluminum nitride (AlN), and silicon nitride (Si ₃ N ₄ ). A ceramic plate can be mentioned.

The thickness of the heat conductive ceramic plate is preferably 10 to 1500 μm, more preferably 20 to 1000 μm in the case of the ceramic plate.

As the insulating adhesive sheet, it is preferable to use a resin having an insulating property such as the thermosetting resin (A) described in the heat dissipation adhesive sheet. In order to improve the thermal conductivity of the insulating layer, it is also preferable to fill it with thermally conductive ceramic particles such as alumina (Al ₂ O ₃ ), boron nitride (BN), aluminum nitride (AlN), and silicon nitride (Si ₃ N ₄ ). ..

The insulating adhesive sheet may also contain a silane coupling agent, an antioxidant, a pigment, a dye, a tackifier resin, a plasticizer, an antifoaming agent, a leveling adjuster, a filler, a flame retardant, etc., if necessary. can.

The thickness of the insulating adhesive sheet is preferably 5 to 100 μm, more preferably 10 to 50 μm.

As the insulating film, a resin film such as polyester, polycarbonate, polyimide, or polyphenylene sulfide can be used. Among these, the polyimide film is preferable from the viewpoint of insulation and durability.
By adding the heat conductive ceramic particles to the insulating film, the heat dissipation can be further improved.

[Structure example 1 of adhesive member for heat dissipation]
Configuration example 1 of the composite member will be described with reference to FIG. 1 (a). In the first configuration example, the heat-dissipating adhesive sheet / insulating layer / heat-dissipating adhesive sheet is heat-pressed to form a laminated structure of the heat-dissipating layer / insulating layer / heat-dissipating layer.

[Structure example 2 of adhesive member for heat dissipation]
Configuration example 2 of the heat radiation laminated body will be described with reference to FIG. 1 (b). In the configuration example 2, the heat-dissipating adhesive sheet / insulating adhesive sheet is heat-pressed to form a heat-dissipating layer / insulating layer.

[Structure example 3 of heat-dissipating adhesive member]
Configuration example 3 of the heat radiation laminated body will be described with reference to FIG. 1 (c). In the configuration example 3, the heat-dissipating adhesive sheet / metal layer / insulating adhesive layer is heat-pressed by heating and pressing the heat-dissipating adhesive sheet / metal layer / insulating adhesive sheet to form a laminated structure of the heat-dissipating layer / metal layer / insulating layer.

<Manufacturing method of laminate for heat-dissipating adhesive member>
As an example of a method for manufacturing a laminated body for a heat-dissipating adhesive member, for example, in the case of a laminated body of a heat-dissipating adhesive sheet / an insulating adhesive sheet, first, a thermosetting resin which is a binder resin softened by heat on a peelable sheet. A composition containing the resin (A) and the dendrite-like metal fine particles (B) is applied to form a heat-dissipating adhesive sheet. The heat-dissipating adhesive sheet may be a single layer or a plurality of layers.
Next, separately, a composition containing an insulating resin is applied onto the peelable sheet to form an insulating adhesive sheet, and the heat radiating adhesive sheet and the insulating adhesive sheet are laminated by laminating to radiate heat adhesion. A laminated body for members can be obtained.

Further, in the case of a laminate of a heat-dissipating adhesive sheet / metal layer / insulating adhesive sheet, first, a heat-dissipating adhesive sheet is formed on the peelable sheet, and a metal layer is formed on the electrolytic copper foil surface side of the electrolytic copper foil with a copper carrier. After laminating and laminating, peel off the copper carrier. Then, there is a method of laminating the surface from which the copper carrier has been peeled off and the insulating adhesive sheet separately formed on the peelable sheet. Further, a heat-dissipating adhesive sheet is formed on the peelable sheet, a metal layer is formed on the surface thereof by electroless plating, and the insulating adhesive sheet separately formed on the peelable sheet and the metal layer are laminated and laminated. The method and the like can be mentioned.

When an insulating heat conductive ceramic plate, an insulating film, or the like is used as the insulating adhesive sheet, it can be separately attached with a conventionally known adhesive, an adhesive, or another adhesive sheet to form a laminate. As the adhesive sheet in this case, the heat dissipation adhesive sheet of the present application may be used.

The peelable sheet is not particularly limited as long as it has releasability, and for example, silicone, alkyd-treated PET film, or the like can be used.

The metal layer can be selected from a metal foil, a vapor deposition film, a sputtering film, and a metal plating film. As the metal foil, for example, a conductive metal foil such as aluminum, copper, silver, or gold is preferable, copper, silver, or aluminum is more preferable, and copper is further preferable from the viewpoint of shielding property and cost.
As copper, for example, it is preferable to use rolled copper foil or electrolytic copper foil, and in pursuit of thinness of the metal layer, those obtained by etching the rolled copper foil or electrolytic copper foil are more preferable. In the case of a metal foil, the thickness is preferably 0.1 to 10 μm, more preferably 0.5 to 5 μm.
The vapor deposition film, the sputtering film, and the metal plating film are preferably formed of a conductive metal material such as aluminum, copper, silver, and gold, and copper, silver, and aluminum are more preferable. The thickness of the thin-film film is preferably 0.1 to 3 μm. The thickness of the sputtering film is preferably 10 to 1000 nm. The thickness of the metal plating film is usually preferably 0.5 to 5 μm.

<< Composite member >>
The composite member of the present invention has a heat dissipation base substrate, a heat dissipation adhesive member formed by heat-pressing a laminate for heat dissipation adhesive member, and a heating element including a member capable of generating heat. The heat-dissipating adhesive member laminate is provided on one surface of the heat-dissipating base substrate, and heat generation includes the member capable of generating the heat on the surface of the heat-dissipating adhesive sheet opposite to the heat-dissipating base substrate side. It is characterized by having a body.
The heat generated from the member that can generate heat is propagated to the heat dissipation base substrate via the heat dissipation adhesive member, so that the heating element is efficiently cooled.

Further, the heat radiating adhesive member is bonded to at least one of the heat radiating base substrate and a heat generating body including a member capable of generating heat by the heat radiating adhesive sheet. The heat-dissipating adhesive sheet is not adhered to the heat-dissipating base substrate and the heat-generating body including a member that can generate heat. May be.

FIG. 2 shows an example of a composite member. FIG. 2 is characterized by a laminated structure in which a heat radiating base substrate and a heat generating body having a conductive member are bonded by the heat radiating adhesive member described in the above [Structure example 1 of the heat radiating adhesive member].

<Dissipation base board>
The heat dissipation base substrate of the present invention will be described.
The heat dissipation base substrate is a member for finally dissipating heat generated from a member capable of generating heat, and a known heat dissipation base substrate can be used as the heat dissipation base substrate of the present invention. Metals and ceramics are preferably used as the heat dissipation base substrate, and are not particularly limited. For example, aluminum, copper, iron, tungsten, molybdenum, magnesium, copper-tungsten alloy, copper-molybdenum alloy, copper-tungsten-molybdenum alloy, etc. Examples thereof include aluminum nitride, silicon carbide, silicon nitride and the like, and they can be used alone or in combination of two or more.

The heat dissipation base substrate may be provided with fins in order to improve heat dissipation efficiency. As the fin, a known one can be used. The shape of the fin is not particularly limited, and examples thereof include a straight fin type, a wavy fin type, an offset fin type, a pin fin type, and a corrugated fin type, and can be appropriately selected and used depending on the purpose of use.

<Heating element>
The heating element in the present invention includes a member capable of generating heat, and examples thereof include a member alone that generates heat, or a form in which the heating element is laminated on a conductive member such as a metal plate via a bonding agent such as solder.

The members of the present invention that can generate heat include various electronic components such as integrated circuits, IC chips, hybrid packages, multi-modules, power transistors, power semiconductor devices, surface resistors, and substrates for LEDs (light emitting diodes). Can be mentioned. In addition, there are other articles used for building materials, vehicles, aircraft, ships, etc., which are easily heated and need to release the heat to the outside in order to prevent performance deterioration. In particular, the above-mentioned heat conductive insulating adhesive member can be suitably used for a power semiconductor module.

The form of the power semiconductor module is not particularly limited, but generally, the power semiconductor element is a laminated body laminated on a conductive member such as a metal plate via a bonding agent such as solder, and further, the laminated body. Has a structure sealed with resin. The conductive member and the heat dissipation base substrate are connected via the above-mentioned heat conductive insulating adhesive member. With this structure, the heat generated when the power semiconductor module is driven is efficiently propagated to the heat dissipation base substrate, and heat is dissipated.

Examples of the conductive member used in the power semiconductor module include metals such as silver, silver, copper, aluminum, nickel, tin, iron and lead, their alloys and carbon, and a circuit pattern is formed. May be. These may be laminated on a resin or ceramic.

The conductive member is laminated between the power semiconductor element and the heat dissipation adhesive member, and also plays a role of transferring the heat generated by the power semiconductor to the heat conductive adhesive member. Therefore, as a result, heat transfer to the heat dissipation base substrate is effectively performed, and heat dissipation of the power semiconductor element is promoted.

<Manufacturing method of composite member>
The composite member is manufactured by installing a heat-dissipating adhesive member laminate between a heating element including a member that can generate heat as described above and a heat-dissipating base substrate, and joining them by heating and pressing.
The above heating press is generally performed under the conditions of a temperature of about 150 to 190 ° C., a pressure of about 1 to 3 MPa, and a time of about 1 to 60 minutes. The heat-dissipating adhesive member, the heat-dissipating base substrate, and the power semiconductor are brought into close contact with each other by a heat press, and the thermosetting resin (A) of the heat-dissipating adhesive sheet flows to fill the voids between the dendrite-like metal fine particles and then heat-cures. Therefore, it has high heat dissipation without seeping out to the end portion.
In addition, in order to promote curing, post-cure may be performed at 150 to 190 ° C. for 30 to 90 minutes after heat crimping.

Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples. The following "parts" and "%" are values based on parts by weight and "% by weight", respectively.

The average particle diameters D ₅₀ and D ₉₀ of the dendrite-like metal fine particles were measured using Microtrac MT3300 manufactured by Nikkiso Co., Ltd. The apparent density was determined by the apparent density test method for metal powder specified in JIS Z 2504: 2000. The tap density was determined by JIS Z 2512: metal powder-tap density measuring method.

The materials used in the examples and comparative examples are shown below.
[Heat dissipation base board]
Heat dissipation base substrate 1: Aluminum block with a thickness of 2 mm [Conductive member]
Conductive member 1: 2 mm copper block

<Examples 1 to 5>
As dendrite-like metal fine particles, a heat-dissipating adhesive sheet was prepared using the materials shown in Table 1.
Urethane resin (manufactured by Toyo Chem Co., Ltd.) is used as the thermosetting resin, and the ratio of the content of the dendrite-like metal fine particles (B) and the thermosetting resin is such that the dendrite-like metal fine particles are used with respect to 100 parts of the resin solid content. A polyethylene terephthalate film having a thickness of 100 μm and having a dry film thickness of 40 μm is coated with a bar coater on a polyethylene terephthalate film having 250 parts and dried at 100 ° C. for 3 minutes to obtain a heat-dissipating adhesive sheet. rice field. However, Example 5 is a reference example.

<Comparative Examples 1 and 2>
Using the metal fine particles shown in Table 1, heat-dissipating adhesive sheets were obtained in the same manner as in Examples 1 to 5.

The description of the coating layer in Table 1 represents the weight% of the metal coating layer in 100% by weight of the dendrite-like metal fine particles (B).

The above Examples and Comparative Examples were evaluated by the following measurement methods and evaluation criteria. The evaluation results are shown in Table 1.

[Preparation of heat-dissipating adhesive member test piece]
A urethane resin (manufactured by Toyo Chem Co., Ltd.) is used as a thermosetting resin, and a polyethylene terephthalate film having a thickness of 100 μm and having a surface peeled off is coated with a bar coater so that the dry film thickness is 40 μm. It was dried at 100 ° C. for 3 minutes to obtain an insulating adhesive sheet. Then, the insulating adhesive sheet and the heat-dissipating adhesive sheet obtained in Examples and Comparative Examples were laminated to prepare a laminated body for a heat-dissipating adhesive member. After peeling off the peelable sheet of the heat-dissipating adhesive sheet and temporarily attaching it to the conductive member 1, the peelable sheet on the insulating adhesive sheet side was peeled off, and the heat-dissipating base substrate 1 was placed on the surface thereof. Then, it was pressed at 150 ° C., 2 MPa for 30 minutes to obtain a heat-dissipating adhesive member test piece.

[Evaluation of resin exudation]
A heat-dissipating adhesive sheet obtained from each Example and each Comparative Example was attached to one surface of a polyimide film having a thickness of 50 μm (“Kapton 200EN” manufactured by Toray DuPont) by laminating, and a hole puncher was used to attach a 5 mm diameter. I made it through the hole.
Separately, a polyimide film having a thickness of 50 μm (“Kapton 200EN” manufactured by Toray DuPont) was prepared and heat-pressed under the conditions of 150 ° C., 2.0 MPa and 30 minutes. After the heat pressing treatment, the hole portion of the heat-dissipating adhesive sheet was observed using a magnifying glass, and the amount of resin seeping out was measured.
The evaluation criteria are as follows.

⊚: The amount of resin exudation of the heat-dissipating adhesive sheet is less than 0.01 mm 〇: The amount of resin exudation of the heat-dissipating adhesive sheet is 0.01 mm or more and less than 0.05 mm ×: The amount of resin exudation of the heat-dissipating adhesive sheet is 0. 05 mm or more

[Evaluation of thermal conductivity]
The obtained heat-dissipating adhesive member test piece is placed on a hot plate at 100 ° C. so that the conductive member side is in contact with the heat source, left for 1 minute, and then the temperature of the heat-dissipating base substrate surface of the heat-dissipating adhesive member test piece is measured by a thermocouple. However, it was evaluated according to the following criteria. It can be said that the higher the thermal conductivity, the better the heat dissipation.

⊚: The temperature of the surface of the heat dissipation base board is 95 ° C or higher 〇: The temperature of the surface of the heat dissipation base board is 90 ° C or higher and less than 95 ° C ×: The temperature of the surface of the heat dissipation base board is less than 90 ° C.

[Evaluation of durability]
The heat-dissipating adhesive member test piece was subjected to 3000 cycles of a cold heat cycle of −40 ° C. to 120 ° C., and then the above-mentioned thermal conductivity was evaluated and evaluated according to the following criteria.

⊚: The temperature of the heat dissipation base substrate surface is 95 ° C or higher 〇: The temperature of the heat dissipation base substrate surface is 90 ° C or higher and less than 95 ° C ×: The temperature of the heat dissipation base substrate surface is less than 90 ° C

From the results shown in Table 1, when the heat-dissipating adhesive sheet of the present invention is used, the heat-dissipating property is excellent, and the heat generated from the member that can generate heat is propagated to the heat-dissipating base substrate via the heat-dissipating adhesive member. As a result, it was confirmed that the heating element can be cooled efficiently.
In addition, since it is possible to suppress the exudation and exudation of the heat-dissipating adhesive sheet during the heating press during the manufacture of composite members, it has good workability and high durability even in harsh environments where cold heat is repeated. It was confirmed that good heat dissipation can be maintained and good operation can be ensured.

1: Heat dissipation layer 2: Insulation layer 3: Metal layer 4: Heat dissipation adhesive member 5: Power semiconductor element 6: Conductive member 7: Heat dissipation base substrate 8: Heating element 10: Composite member

Claims (5)

A laminated body for a heat-dissipating adhesive member arranged between a heat-dissipating base substrate and a heating element including a member that can generate heat.
It has a heat radiating adhesive sheet for adhering to at least one of the heat radiating base substrate and a heat generating body including a member capable of generating heat, and an insulating layer.
The heat-dissipating adhesive sheet is a laminate for a heat-dissipating adhesive member containing a thermosetting resin (A) and dendrite-like metal fine particles (B) having an average particle diameter D50 of 7 to 20 μm. A composite member having a heat dissipation base substrate, a heat dissipation adhesive member, and a heating element including a member capable of generating heat.
The heat-dissipating adhesive member has an insulating layer and a heat-dissipating layer.
The heat dissipation layer is formed by heat-pressing an adhesive sheet for heat dissipation containing a thermosetting resin (A) and dendrite-like metal fine particles (B) having an average particle diameter D50 of 7 to 20 μm, and has a thickness of 5 to 5 to. It ’s a 30 μm layer,
The heat-dissipating adhesive member is provided on one surface of the heat-dissipating base substrate.
A composite member in which a heat generating body including a member capable of generating the above heat is provided on a surface of the heat radiating adhesive member opposite to the heat radiating base substrate side. The insulating layer is a heat conductive ceramic plate selected from alumina (Al ₂ O ₃ ), boron nitride (BN), aluminum nitride (AlN), and silicon nitride (Si ₃ N ₄ ), and is the same as the heat conductive ceramic plate. The composite member according to claim 2, wherein the thickness is 10 to 1500 μm. The composite member according to claim 2 to 3, wherein the member capable of generating heat is a power semiconductor element. The composite member according to claim 4, wherein a conductive member is provided between the power semiconductor element and the heat-dissipating adhesive member.

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