JPH10183086A - Heat-conductive adhesive composition and heat-conductive adhesive film using the composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a heat-conductive adhesive compsn. and a heatconductive adhesive film which can improve both the heat conductivity and the adhesion and possess excellent moisture resistance, heat resistance, insulation reliability, cracking resistance, and flexibility. SOLUTION: This heat-conductive adhesive compsn. comprises: 100 pts.wt. in total of an epoxy resin and a curing agent; 1 to 40 pts.wt. high-mol.wt. resin which is compatible with an epoxy resin and has a wt. average mol.wt. of not less than 30,000; 20 to 100 pts.wt. high-mol.wt. resin, with a wt. average mol.wt. of not less than 100,000, having a reactive functional group, 0.1 to 5 pts.wt. curing accelerator; and an inorg. filler in an amt. of 60 to 200 pts.vol. based on 100 pts.vol. resin. The heat-conductive adhesive film is prepd. by coating a substrate with the above compsn. and bringing the degree of curing of the coating to such a state that heat generation in an amt. of 10 to 40% of the total curing calorific value as measured by DSC(differential scanning calorimetry) has been completed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a heat conductive adhesive composition and a heat conductive adhesive film formed from the heat conductive adhesive composition.

[0002]

2. Description of the Related Art In recent years, the density of wiring for semiconductor packages such as multilayer wiring boards, PGAs, and BGAs, the mounting density of electronic components has increased, and the amount of heat generated per unit area has increased due to the high integration of semiconductor elements. It has been desired that heat dissipation from a semiconductor package be improved, for example, as the size increases. Although heat management has become important along with this, hitherto, a thermosetting adhesive film having good heat conductivity and having high levels of heat resistance and moisture resistance has not been obtained.

[0003] Conventionally, as a thermally conductive adhesive, a rubber-based adhesive to which an inorganic filler is added has been known. This is an adhesive mainly composed of various rubbers such as acrylic rubber and acrylonitrile butadiene rubber, and these rubbers are used to improve the strength, flexibility and adhesion of the adhesive.

[0004]

However, among these, in the system containing acrylic rubber as a main component, the decrease in adhesive strength after long-time high-temperature treatment is relatively small, but the adhesive strength at high temperature is insufficient. In addition to the above, there is a disadvantage that the property is significantly deteriorated when absorbing moisture. Further, in a system containing NBR as a main component, the adhesive strength after long-time treatment at high temperature is greatly reduced,
There were drawbacks such as poor electrical corrosion resistance. In particular, PCT
When a moisture resistance test was performed under severe conditions of recent electronic devices such as processing, deterioration was large. Japanese Patent Application Laid-Open No. 60-243180 discloses an improved solder heat resistance after moisture absorption.
There is an adhesive containing an acrylic resin, an epoxy resin, a polyisocyanate and an inorganic filler shown in JP-A No.
Japanese Patent Application Laid-Open No. 61-138680 discloses an acrylic resin, an epoxy resin, and an adhesive containing a primary amine compound having a urethane bond in the molecule and having both ends terminated with a primary amine compound and an inorganic filler. No. 243180,
10 to 10 parts by weight of the inorganic filler with respect to 100 parts by weight of the resin mixture
45 parts by weight.
No. 8680 discloses that 10 to 100 parts of an inorganic filler is added to 100 parts by weight of a resin mixture, and the effect of improving thermal conductivity is not so large.

Further, among rubber-epoxy resin adhesives, there are adhesives in which epoxy resins such as reactive acrylic rubber and acrylonitrile butadiene rubber are mixed, and these adhesives have improved high-temperature adhesion and the like. .

As a reactive rubber-based adhesive, a reactive acrylic-based adhesive is disclosed in Japanese Patent Application Laid-Open No. 3-181580, in which an acrylic elastomer containing a carboxyl group, a hydroxyl group, and an epoxy group, an alkylphenol, an epoxy resin, an imidazolium trioxide. There is an adhesive composition comprising melitate, which is used in the field of bonding a base film of a flexible printed wiring board and a copper foil. Further, Japanese Patent Application Laid-Open No. 7-7 / 1994 improves the adhesiveness to a glossy surface and the heat resistance.
No. 6679, 60-80 parts by weight of an acrylic elastomer having an epoxy group, 8-20 parts by weight of an alkylphenol, 8-20 parts by weight of an epoxy resin, and 0.2-1.0 parts by weight of an imidazole-based curing agent. There is an adhesive composition for a seat heater with a circuit.
As disclosed in JP-A-173449, there is an epoxy group-containing acrylic elastomer-based adhesive composition containing an epoxy group-containing acrylic rubber as a main component.

It is easy to guess that a thermal conductive adhesive can be obtained by adding a filler to these adhesives. However, when a filler is mixed with the adhesive, the thermal conductivity is improved, but at the same time, the adhesiveness is reduced. There was a problem of lowering. As a reason for this, it is considered that when the proportion of the filler is increased, the probability that the filler which does not contribute to the adhesion is present on the surface of the adhesive in contact with the adherend is increased, and thus the adhesiveness is reduced. In order to avoid this, for example, the same effect can be obtained by providing a thin layer of only resin on the surface layer, but there is a problem that the manufacturing cost is significantly increased.

The present invention has been made in view of such circumstances, and aims at achieving both thermal conductivity and adhesiveness.
An object of the present invention is to provide a thermally conductive adhesive composition having excellent moisture resistance, heat resistance, insulation reliability, crack resistance, and flexibility, and a thermally conductive adhesive film using the composition.

[0009]

In order to achieve the above object, the present invention provides (1) a total of 100 parts by weight of an epoxy resin and a curing agent thereof, and (2) a weight-average molecular weight compatible with the epoxy resin. 1 to 40 parts by weight of high molecular weight resin of 30,000 or more, (3) weight average molecular weight 1 having a reactive functional group
20 to 100 parts by weight of a high molecular weight resin of 100,000 or more, (4) 0.1 to 5 parts by weight of a curing accelerator and (5) an inorganic filler,
A heat conductive adhesive composition containing 60 to 200 parts by volume with respect to 100 parts by volume of the resin. Further, the present invention is characterized in that the high-molecular-weight resin having a weight average molecular weight of 100,000 or more having a reactive functional group is an acrylic rubber containing 1 to 10 mol% of an epoxy group, and the inorganic filler is alumina,
Further, these adhesive compositions are applied on a substrate, and the degree of cure is measured by using DSC (differential scanning calorimetry). It is a heat conductive adhesive film obtained. Further, the present invention provides
A heat conductive adhesive film applied to a metal foil with an adhesive obtained by applying or sticking the above heat conductive adhesive composition on a metal foil.

The present invention relates to a multilayer printed wiring board, PGA, B
It is an adhesive that has both thermal conductivity and adhesiveness necessary for wiring boards for semiconductor packages such as GA, and has moisture resistance, heat resistance, and adhesive strength at high temperatures. It has excellent circuit filling properties and adhesion. In addition, it imparts both fluidity and improved handleability.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (1) Used in the present invention
The epoxy resin is not particularly limited as long as it hardens and exhibits an adhesive action, but an epoxy resin having a bifunctional or higher molecular weight of less than 5,000, preferably less than 3,000 is suitably used. . In particular, it is preferable to use a bisphenol A type or bisphenol F type liquid resin having a molecular weight of 500 or less, since the fluidity during lamination can be improved. Bisphenol A type or bisphenol F type liquid resin having a molecular weight of 500 or less is obtained from Yuka Shell Epoxy Co., Ltd.
7, marketed under the trade name Epicoat 828.
In addition, Dow Chemical Japan Co., Ltd. E. FIG. R.
330, D.I. E. FIG. R. 331; E. FIG. R. 361. Further, they are commercially available from Toto Kasei Co., Ltd. under the trade names of YD128 and YDF170.

A polyfunctional epoxy resin may be added for the purpose of increasing the Tg. Examples of the polyfunctional epoxy resin include a phenol novolak epoxy resin and a cresol novolak epoxy resin.

The phenol novolak type epoxy resin is
It is commercially available from Nippon Kayaku Co., Ltd. under the trade name EPPN-201. Cresol novolak type epoxy resin was obtained from Sumitomo Chemical Co., Ltd. as ESCN-0.
01, under the trade name ESCN-195,
EOCN1012, EOCN1 from Nippon Kayaku Co., Ltd.
025, EOCN1027.

The curing agent for the epoxy resin (1) used in the present invention is not particularly limited, but a phenol novolak resin or a bisphenol novolak resin which is a compound having two or more phenolic hydroxyl groups in one molecule. It is preferable to use a cresol novolak resin. This is because it is excellent in adhesiveness at the time of moisture absorption and electric corrosion resistance.

As such a curing agent, phenolite LF2882, phenolite LF2822, phenolite TD-2090, and phenolite LF2882 from Dainippon Ink and Chemicals, Inc.
Phenolite TD-2149, Phenolite VH415
0, commercially available under the trade name Phenolite VH4170.

As the curing accelerator (4) used in the present invention, various imidazoles are preferably used. Examples of the imidazole include 2-methylimidazole, 2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-phenylimidazolium trimellitate, and the like.

Imidazoles are commercially available from Shikoku Chemicals Corporation under the trade names 2E4MZ, 2PZ-CN, and 2PZ-CNS.

The high molecular weight resin having a weight average molecular weight of 30,000 or more, which is compatible with the epoxy resin (2) used in the present invention, includes phenoxy resin, high molecular weight epoxy resin, ultrahigh molecular weight epoxy resin, and carboxyl group. And functional group-containing rubbers. The weight average molecular weight is set to 30,000 or more in order to reduce the tackiness of the adhesive in the B stage and improve the flexibility at the time of curing. Examples of the rubber having a high polarity functional group include a rubber obtained by adding a high polarity functional group such as a carboxyl group to an acrylic rubber. Here, “compatible with the epoxy resin” refers to a property of forming a homogeneous mixture without being separated from the epoxy resin and being separated into two or more phases after curing. Phenoxy resin was purchased from Toto Kasei Co., Ltd. as Fetote YP-4.
0, Fetote YP-50 and Fetote YP-60.

The high molecular weight epoxy resin has a molecular weight of 3-8.
10,000 high molecular weight epoxy resins, and ultrahigh molecular weight epoxy resins having a molecular weight exceeding 80,000 (Japanese Patent Publication No. 7-59617).
No., Tokuhei 7-59618, Tokuhei 7-59619
No., Tokuhei 7-59620, Tokuhei 7-64911
And Japanese Patent Publication No. 7-68327), all of which are manufactured by Hitachi Chemical Co., Ltd. Carboxyl group-containing acrylonitrile-butadiene rubber is commercially available from Japan Synthetic Rubber Co., Ltd. under the trade name PNR-1 and from Zeon Corporation under the trade name Nipol 1072. The amount of the high-molecular-weight resin that is compatible with the epoxy resin and has a weight average molecular weight of 30,000 or more depends on the flexibility of the epoxy resin-based phase (hereinafter referred to as epoxy resin phase) and the tackiness. The amount is set to 1 part by weight or more to prevent reduction in the insulating property due to cracks and the like, and to 40 parts by weight or less to prevent a decrease in Tg of the epoxy resin phase.

The high molecular weight resin having a reactive functional group and having a weight average molecular weight of 100,000 or more used in the present invention includes acrylic rubber containing epoxy group, NB
R and the like.

Further, the weight average molecular weight of the high molecular weight resin having a reactive functional group needs to be 100,000 or more and 2,000,000 or less, preferably 800,000 or more and 2,000,000 or less. When the weight average molecular weight of the high molecular weight resin is less than 100,000, the flexibility of the adhesive film decreases, and the flow property becomes too large, and it becomes difficult to control the amount of resin leached. On the other hand, if it exceeds 2,000,000, the flowability is reduced, and the circuit filling property is deteriorated, which is not preferable.

The compounding amount of the high molecular weight resin having a reactive functional group and having a weight average molecular weight of 100,000 or more is 20 to 100.
Parts by weight. When the amount is less than 20 parts by weight,
It is not preferable because the strength of the film is small and the tackiness becomes large, and if it exceeds 100 parts by weight, the insulation reliability at high temperatures, the heat resistance, and the moisture resistance decrease, which is not preferable.

In the present invention, a coupling agent may be blended as an adhesive in order to improve interfacial bonding between different materials. As the coupling agent, a silane coupling agent is preferable. As a silane coupling agent, γ
-Glycidoxypropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-ureidopropyltriethoxysilane, N-β-aminoethyl-γ-aminopropyltrimethoxysilane and the like. Can be

The above-mentioned silane coupling agent is such that γ-glycidoxypropyltrimethoxysilane is NUC A-
187, γ-mercaptopropyltrimethoxysilane is NUC A-189, γ-aminopropyltriethoxysilane is NUC A-1100, γ-ureidopropyltriethoxysilane is NUC A-1160, N-β-
Aminoethyl-γ-aminopropyltrimethoxysilane is commercially available from Nippon Unicar Co., Ltd. under the trade name NUC A-1120.

The amount of the coupling agent to be added is preferably 0.1 to 10 parts by weight based on 100 parts by weight of the resin in view of the effect of the addition, heat resistance and cost.

Further, in order to adsorb ionic impurities and improve insulation reliability at the time of moisture absorption, an ion scavenger can be blended. The compounding amount of the ion scavenger is preferably 5 to 10 parts by weight in view of the effect, heat resistance and cost of the addition. As the ion scavenger, a compound known as a copper harm inhibitor, for example, a triazine thiol compound or a bisphenol-based reducing agent for preventing ionization and dissolution of copper can also be blended. As the bisphenol-based reducing agent, 2,2′-methylene-bis- (4-methyl-
6-tert-butylphenol), 4,4'-thio-bis- (3-methyl-6-tert-butylphenol) and the like. A copper damage inhibitor containing a triazine thiol compound as a component is commercially available from Sankyo Pharmaceutical Co., Ltd. under the trade name Disnet DB. In addition, a copper damage inhibitor containing a bisphenol-based reducing agent as a component is available from Yoshitomi Pharmaceutical Co., Ltd.
It is marketed under the trade name Yoshinox BB.

As the inorganic ion adsorbent, a product containing a zirconium-based compound as a component IX-100 from Toa Gosei Chemical Industry Co., Ltd. and a product containing an antimony bismuth-based compound as a component IXE-600 are available.
And a product containing a magnesium aluminum compound as a component under the trade name IXE-700. Further, there is a hydrotalcite that is commercially available from Kyowa Chemical Industry under the trade name of DHT-4A.

Further, in the present invention, 60 to 200 parts by volume of the inorganic filler (5) is blended with respect to 100 parts by volume of the resin. The purpose of the inorganic filler is to improve the thermal conductivity of the adhesive film, to provide flame retardancy, to adjust the melt viscosity, to provide thixotropic properties, and to improve the surface hardness. is there. If the compounding amount of the inorganic filler is less than 60 parts by volume with respect to 100 parts by volume of the resin, the effect of the compounding is small, and if the compounding amount exceeds 200 parts by volume, the flexibility of the adhesive is reduced, the adhesiveness is reduced, and voids are reduced. Problems such as lowering of the withstand voltage due to the residual occur. In addition,
In the case where 100 parts or more are blended, it is necessary to use one having an appropriate particle size distribution with good packing.

As the inorganic filler, aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, calcium silicate, calcium oxide, magnesium oxide, alumina, aluminum nitride, aluminum borate whisker, boron nitride, crystalline silica, amorphous Silica,
And silicon carbide.

In particular, in order to improve thermal conductivity, alumina, aluminum nitride, boron nitride, crystalline silica,
Amorphous silica and silicon carbide are preferred.

Of these, alumina is preferred because of its good thermal conductivity, good heat resistance and good insulation. In addition, crystalline silica or amorphous silica is inferior to alumina in terms of thermal conductivity, but has less ionic impurities, so it has high insulation properties during PCT treatment, and corrodes copper foil, aluminum wire, aluminum plate, etc. Is preferred in that there is little.

In order to provide flame retardancy, aluminum hydroxide and magnesium hydroxide are preferred. Aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, calcium silicate, magnesium silicate, calcium oxide, magnesium oxide, alumina, crystalline silica, amorphous silica Silica is preferred.

Regarding the improvement of surface hardness, short fiber alumina and potassium titanate, calcium sulfate, zinc oxide,
Inorganic whiskers such as aluminum borate are preferred. Further, in the present invention, as the metal filler, powders of copper, silver, aluminum, titanium, and alloys thereof and short fiber-like powders can be used. Further, silicon powder, silicon carbide powder, or the like, which is a semiconductor filler, can also be used.

The heat conductive adhesive composition of the present invention can be used as a varnish as it is, or by dissolving and dispersing each component in a solvent to form a varnish, coating the composition on a substrate, and heating to remove the solvent. It can be used in a film state. The varnishing solvent is relatively low boiling point, methyl ethyl ketone,
It is preferable to use acetone, methyl isobutyl ketone, 2-ethoxyethanol, toluene, butyl cellosolve, methanol, ethanol, 2-methoxyethanol and the like. Further, a high boiling point solvent may be added for the purpose of improving the coating properties. Examples of the high boiling point solvent include dimethylacetamide, dimethylformamide, methylpyrrolidone, cyclohexanone and the like. The production of the varnish can be carried out by a mill, a three-roll mill, a bead mill or the like, or a combination thereof, in consideration of the dispersion of the inorganic filler. By mixing the filler and the low molecular weight material in advance and then blending the high molecular weight material, the time required for mixing can also be reduced. After the varnish is formed, it is preferable to remove bubbles in the varnish by vacuum degassing. As the substrate, a polyester film, a polyethylene film, a polypropylene film, a polyimide film, or the like, or a film obtained by subjecting them to a release treatment can be used.

Further, a metal foil such as a copper foil or an aluminum foil can be used as the base material. Using a metal foil as a substrate, by applying the adhesive composition of the present invention, as a metal foil with an adhesive, further, aluminum plate, screen printing or coating on a copper plate, or by pasting a film It is also possible to use. These metal foils are preferably subjected to a surface roughening treatment such as a mat treatment.

After the adhesive composition varnish is applied or printed on these, it is necessary to dry the solvent to slightly cure the adhesive.

An adhesive varnish is applied on a base material such as the above plastic film and dried by heating to remove the solvent.
The adhesive film thus obtained is in a state where heat generation of 10 to 40% of the total curing calorific value measured using DSC has been completed. Heat is applied when the solvent is removed. At this time, the curing reaction of the adhesive composition proceeds and gels. The cured state at that time affects the fluidity of the adhesive, and optimizes adhesiveness and handleability. The DSC (differential scanning calorimetry) is based on a zero-position method of supplying or removing a calorific value so as to constantly cancel the temperature difference between a standard sample having no heat generation and heat absorption within a measurement temperature range. The device is commercially available and can be measured using it. The reaction of the resin composition is an exothermic reaction, and when the sample is heated at a constant heating rate,
The sample reacts and generates heat. The calorific value is output to a chart, and a heating curve and an area surrounded by the base line are obtained based on the base line, and this is defined as a calorific value. Measured from room temperature to 250 ° C at a heating rate of 5 to 10 ° C / min,
The calorific value described above is obtained. Some of these are performed automatically, and can be easily performed by using them. Next, the calorific value of the adhesive obtained by applying and drying the above base film is determined as follows. First,
The total calorific value of the uncured sample obtained by drying the solvent using a vacuum dryer at 25 ° C. is measured, and this is defined as A (J / g). Next, the calorific value of the coated and dried sample was measured.
And The curing degree C (%) of the sample (the state in which heat generation is completed by heating and drying) is given by the following equation (1).

[0038]

## EQU1 ## C (%) = (A−B) × 100 / A

The degree of curing of the heat conductive adhesive film was 10% of the total curing calorific value when measured using DSC.
It is necessary to end the heating up to 40%.

If the degree of cure is less than 10%, the network structure is not sufficiently generated, so that the liquid component and the inorganic filler flow together and adhere to the surface to be adhered, which is not preferred in that the adhesiveness is reduced. On the other hand, if the degree of curing exceeds 40%, the network structure becomes dense, and other liquid components are cured, so that the fluidity of the liquid component and the inorganic filler is reduced, and the adhesiveness is undesirably reduced.

The heat conductive adhesive of the present invention is characterized in that a part of the adhesive is gelled to form a network structure. As a result, components of the liquid resin smaller than the network can pass through the network, whereas inorganic fillers added in a larger amount than the network cannot move through the network because they cannot pass through the network. Although it oozes out on the surface of the adhesive in contact with the adherend and contributes to adhesion, it is considered that the inorganic filler does not ooze out on the surface of the adhesive, so that the adhesiveness does not decrease. That is, since only the resin selectively oozes out onto the surface of the adherend, the adhesiveness becomes good and a heat conductive adhesive film having good heat conductivity can be obtained.

A feature of the adhesive according to the present invention is that the mixing ratio of epoxy resin such as acrylic rubber containing epoxy group and epoxy resin in the heat conductive adhesive composition is large. Epoxy resin has relatively high Tg,
In addition, since the moisture resistance is good, the moisture resistance and the heat resistance can be improved by increasing the mixing ratio of the epoxy resin.

The above features are summarized as follows. 1) Since many unreacted epoxy resin components remain, when pressure is applied, unreacted components leach out of the gel. Therefore, even when a large amount of filler is contained, the adhesiveness is reduced and the circuit filling property is reduced. Less decrease. That is, when the adhesive composition is dried, the weight average molecular weight having a reactive functional group is 1
The epoxy group and the epoxy resin contained in the acrylic rubber, which is a high molecular weight resin of 100,000 or more, react with each other, but the acrylic rubber has a large molecular weight and contains a large number of epoxy groups in one molecular chain, so the reaction has proceeded slightly. Even if it gels. (Normally, gelation occurs in the state where heating of 10 to 40% of the total curing calorific value measured by DSC is completed, that is, gelation occurs in the first half of the A or B stage.) It is gelled in a state containing many components, the melt viscosity is significantly increased and the fluidity is low as compared with the case where it is not gelled. 2) Moisture resistance is improved by using epoxy resin as a main component. 3) By using a high molecular weight resin having a large molecular weight, the film strength and flexibility of the adhesive film can be exhibited. 4) By using the epoxy group-containing acrylic rubber specified in the present invention, it is possible to impart a withstand voltage and an electrolytic corrosion resistance. 5) By mixing an inorganic filler, tackiness can be reduced. 6) Since the high molecular weight resin is gelled, even if pressure is applied when a large number of unreacted components of the epoxy resin remain, the unreacted components flow extremely and a large amount of leaching occurs, No defect such as covering the connection terminal occurs. 7) Since the adhesive can be formed into a film with a large amount of unreacted components such as an epoxy resin, there is an advantage that the life (effective use period) of the adhesive sheet is extended. 8) In addition to the above effects, it is possible to impart properties such as improving the thermal conductivity of the adhesive, imparting flame retardancy to the adhesive, giving an appropriate viscosity at the temperature at the time of bonding, and improving the surface hardness. Hereinafter, the heat conductive adhesive composition according to the present invention and the heat conductive adhesive film using the composition will be specifically described with reference to Examples.

[0044]

【Example】

<Example 1> A heat conductive adhesive film was prepared from the composition shown below.

Bisphenol A type epoxy resin (epoxy equivalent = 200, trade name, manufactured by Yuka Shell Epoxy Co., Ltd., Epicoat 828) was used as the epoxy resin.
5 parts by weight, 15 parts by weight of cresol novolak type epoxy resin (trade name of ESCN001 manufactured by Sumitomo Chemical Co., Ltd.) and bisphenol A type novolak resin (trade name of Dainippon Ink and Chemicals Co., Ltd.) as a curing agent,
Phenoxy resin (molecular weight: 50,000, trade name, manufactured by Toto Kasei Co., Ltd., Fetoto YP) was used as a high-molecular-weight resin having a weight-average molecular weight of 30,000 or more, which was 40 parts by weight using Pryofen LF2882. Acrylic rubber containing epoxy groups (molecular weight: 1,000,000, trade name, HTR-860P, manufactured by Teikoku Chemical Industry Co., Ltd.) as a high-molecular weight resin having a reactive functional group and having a weight average molecular weight of 100,000 or more, 45 parts by weight, 0.5 part by weight of 1-cyanoethyl-2-methylimidazole (trade name, manufactured by Shikoku Chemicals Co., Ltd., Curesol 2PZ-CN) as a curing accelerator, γ-
Glycidoxypropyl tritomexisilane (NUC A-187 manufactured by Nippon Unicar Co., Ltd. was used)
To a composition consisting of 0.5 parts by weight, methyl ethyl ketone is added, and alumina having an average particle size of 0.4 μm (AL-160-, trade name, manufactured by Showa Denko KK) is further used as an inorganic filler.
150 parts by weight (using SG-1) and 100 parts by weight of alumina (using AS-50, trade name, manufactured by Showa Denko KK) having an average particle size of 5 μm were added. This was mixed with a bead mill, and the viscosity was adjusted by further adding methyl ethyl ketone, followed by vacuum degassing. The obtained varnish is applied on a release-treated polyethylene terephthalate film having a thickness of 70 μm as a base material, and dried by heating at 110 ° C. for 15 minutes. Was prepared. The degree of cure of the adhesive film in this state was measured using DSC (912 type DSC manufactured by DuPont) (heating rate, 10 ° C./min). As a result, heat generation of 20% of the total curing calorific value was completed. Condition.

<Example 2> A 400 parts by weight of alumina having an average particle size of 5 μm and a phenoxy resin (molecular weight: 50,000, trade name, manufactured by Toto Kasei Co., Ltd., Fetote YP) were used.
(Using -50) was changed to 2 parts by weight to produce an adhesive film in the same manner as in Example 1. The degree of cure of the adhesive film in this state was measured using a DSC, and as a result, the heat generation was 15% of the total curing calorific value.

<Example 1> Table 1 shows the composition of <Example 2>.

[0048]

[Table 1] ―――――――――――――――――――――――――――― Item Product name Example 1 Example 2 ―――――――― ―――――――――――――――――――――― Epoxy resin Ehjicoat 828 45 45 ESCN-001 15 15 Curing agent Phuraio-fen LF2882 40 40 Compatible high molecular weight resin YP-50 15 2 Reactive high molecular weight resin HTR-860P-3 45 45 HTR-860 0 0 Curing accelerator 2PZ-CN 0.5 0.5 Silane coupling agent NUC A-187 0.5 0.5 Inorganic filler AL-160-SG-1 150 0 AS-50 100 400 100 parts of resin 68 105 Filler volume part ――――――――――――――――――――――――――――

<Comparative Example 1> An epoxy group-containing acrylic was replaced with an unmodified acrylic rubber (HTR- manufactured by Teikoku Chemical Industry Co., Ltd.).
860) The adhesive film was prepared in the same manner as in Example 1 except that the weight was changed to 45 parts by weight.

Comparative Example 2 An adhesive film was prepared in the same manner as in Example 2 except that the amount of alumina was changed from 400 parts by weight to 100 parts by weight.

Comparative Example 3 An adhesive film was produced in the same manner as in Example 2 except that the amount of alumina was changed from 400 parts by weight to 700 parts by weight.

<Comparative Example 4> The varnish of Example 1 was applied to a thickness of 7
0 μm release-treated polyethylene terephthalate film, applied at a higher temperature than in Example 1 for the same time
The resultant was dried by heating at 150 ° C. for 15 minutes to produce an adhesive film having a thickness of 0.1 mm. The curing degree of the adhesive in this state is
As a result of measurement using DSC, it was in a state where heat generation of 50% of the total curing calorific value was completed.

<Comparative Example 5> The varnish of Example 1 was applied to a thickness of 7
0 μm release coated polyethylene terephthalate film, applied at lower temperature than in Example 1 for the same time 1
It was dried by heating at 00 ° C. for 15 minutes to produce an adhesive film having a thickness of 0.1 mm. The degree of cure of the adhesive film in this state was measured using a DSC, and as a result, heat generation of 7% of the total curing calorific value was completed.

Table 2 shows the composition of <Comparative Example 1> to <Comparative Example 5>.

[0055]

[Table 2] ―――――――――――――――――――――――――――――――――― Item Item name Comparative example 1 2 3 4 5 ― ――――――――――――――――――――――――――――――――――― Epoxy resin Echicoat 828 45 45 45 45 45 ESCN-001 15 15 15 15 15 Curing agent Periophen LF2882 40 40 40 40 40 Compatible high molecular weight resin YP-50 15 0 0 10 10 Reactive high molecular weight resin HTR-860P-3 0 45 45 45 45 HTR-860 4500
0 0 Curing accelerator 2PZ-CN 0.5 0.5 0.5 0.5 0.5 Silane coupling agent NUC A-187 0.5 0.5 0.5 0.5 0.5 Inorganic filler AL-160-SG-1 150 0 0 150 150 AS-50 100 100 700 100 100 Resin 100 68 25 210 68 68 Volume part of filler ――――――――――――――――――――――――――――――――――――

Next, the adhesive films obtained in Examples 1 and 2 and Comparative Examples 1 to 5 were cured by heating at 170 ° C. for 30 minutes, and various characteristics of the cured heat conductive adhesive film were examined. The results are shown in Table 3. In addition, the obtained adhesive film was bonded by heating and pressing a copper foil having a thickness of 35 μm and 50 mm × 50 mm and an aluminum plate having a thickness of 2 mm and 50 mm × 50 mm at a temperature of 170 ° C. and a pressure of 1.96 MPa for 30 minutes. did. Thereafter, the periphery of the copper foil was etched for withstand voltage measurement to leave a circular portion having a diameter of 20 mm. A copper foil having a width of 10 mm was left for measuring the peeling strength.

The test method is as follows. Adhesion: temperature 121 ° C, relative humidity 100%, atmospheric pressure 202
With respect to the test pieces before and after the treatment for 96 hours using a pressure cooker of 6 hPa, those having peeled between the layers were regarded as defective, and those without peeling between the layers were regarded as good.

Flexibility: Adhesive film with a diameter of 1 at 25 ° C.
It was wound around a 0 mm cylinder and evaluated by the presence or absence of cracks.

Withstand voltage: temperature 121 ° C., relative humidity 100
The test pieces before and after the treatment for 96 hours were immersed in insulating oil using a pressure cooker with a pressure of 2026 hPa and a pressure of 2026 hPa, and an AC voltage was applied between the copper foil and the aluminum plate at room temperature to measure the voltage at which dielectric breakdown occurred. The unit of the withstand voltage is kV.

Amount of leaching: A 100 mm × 100 mm adhesive film with a 6 mm diameter hole and a thickness of 2 mm,
A 100 mm x 100 mm aluminum plate was heated at a temperature of 17
Heating and pressing were performed at 0 ° C. and a pressure of 1.96 MPa for 30 minutes for bonding. After that, measure the length of resin leached from the hole,
The amount of leaching was used. Those with an leaching amount of 1.5 mm or less were determined to be good, and those with a leaching amount of more than 1.5 mm were determined to be defective.

Circuit filling: pattern (pattern width 0.5)
mm, glass epoxy double-sided board (base material thickness: 200 μm, copper foil thickness: 35 μm)
m) and a 100 mm × 100 mm adhesive film and a 2 mm thick, 100 mm × 100 mm aluminum plate were bonded by heating and pressing at a temperature of 170 ° C. and a pressure of 1.96 MPa for 30 minutes. After that, the cross section was observed with an optical microscope, and the glass epoxy double-sided board, the adhesive film, those in which no void was generated between the aluminum plates were determined to be good,
Those having voids were determined to be defective.

Workability: The adhesive film was perforated with a punch, cracks and the like or resin scraps were regarded as defective, and those without such defects were evaluated as good.

Peel strength: The copper foil and the substrate were peeled off at an angle of 90 ° at a pulling speed of 50 mm / min. Others conformed to JIS C6481.

Thermal resistance: The obtained adhesive film (thickness 10
0 μm) and a copper foil having a thickness of 35 μm and a size of 30 mm × 30 mm and an aluminum plate having a thickness of 2 mm and a size of 30 mm × 30 mm were bonded by heating and pressing at a temperature of 170 ° C. and a pressure of 1.96 MPa for 30 minutes. Thereafter, the periphery of the copper foil was etched to form a rectangular portion of 10 mm × 14 mm.
A transistor (2SC2233) was fixed to the copper foil of this test piece with solder, and a current was passed through the transistor on the heat dissipation block so that the aluminum plate side was in contact with the heat dissipation block. Then, the temperature of the transistor (T
1) and the temperature (T2) of the heat radiating block were measured, and the thermal resistance (X) was calculated from the measured value and the applied power (W) by the following equation (2). Table 3 shows the results.

[0065]

X = (T1-T2) / W (Equation 2)

Thermal conductivity: Thermal conductivity was measured at 25 ° C. using a thermoconductivity meter using an adhesive film.

[0067]

[Table 3]

As is clear from Table 3, Examples 1 and 2 show that each of Examples 1 and 2 has an adhesive containing an epoxy resin and its curing agent, a reactive high molecular weight component, and an epoxy group-containing acrylic rubber specified in the present invention. Agent. These have low thermal resistance, which is a measure of thermal conductivity, have high thermal conductivity, and have good withstand voltage and adhesion after PCT treatment.
Good crack resistance, flexibility and workability. Leaching volume,
Circuit filling is also good.

Further, Comparative Example 1 does not contain a reactive high molecular weight resin, so that the adhesion is low. Comparative Example 2
Has a small amount of filler and has poor thermal conductivity as compared with the examples. In Comparative Example 3, the thermal conductivity was good because the amount of the filler was too large, but the adhesiveness was reduced, and the flexibility and workability were also poor. Comparative Example 4
When a copper foil with an insulating adhesive layer is produced, the curing is excessively advanced, so that the fluidity is poor and the adhesiveness and the circuit filling property are poor. On the contrary, in Comparative Example 5, the flowability is lowered due to insufficient curing.

[0070]

As described above, as described above, the heat conductive adhesive composition or the heat conductive adhesive film according to the present invention comprises:
In addition to achieving both thermal conductivity and adhesiveness, moisture resistance,
It has the effect of being excellent in heat resistance, insulation reliability, crack resistance, and flexibility.

Claims (5)

[Claims] 1. A total of 100 parts by weight of (1) an epoxy resin and a curing agent thereof, and (2) a high-molecular weight resin having a weight-average molecular weight of 30,000 or more, which is compatible with the epoxy resin.
0 parts by weight, (3) 20 to 100 parts by weight of a high molecular weight resin having a reactive functional group and having a weight average molecular weight of 100,000 or more,
(4) A heat conductive adhesive composition containing 0.1 to 5 parts by weight of a curing accelerator and (5) 60 to 200 parts by volume of 100 parts by weight of an inorganic filler. 2. A high molecular weight resin having a reactive functional group and having a weight average molecular weight of 100,000 or more is an acrylic rubber containing 1 to 10 mol% of an epoxy group.
3. The heat conductive adhesive composition according to item 1. 3. The heat conductive adhesive composition according to claim 1, wherein the inorganic filler is alumina. 4. A case where the thermally conductive adhesive composition according to any one of claims 1 to 3 is applied on a substrate, and the degree of curing is measured by using DSC (differential scanning calorimetry). A heat conductive adhesive film characterized in that heat generation of 10 to 40% of the total curing calorific value has been completed. 5. A heat conductive adhesive film, wherein the heat conductive adhesive composition according to any one of claims 1 to 3 is applied or stuck on a metal foil.