JP5983694B2 - Anisotropic conductive adhesive - Google Patents

Description

  The present invention relates to an anisotropic conductive adhesive.

  As a technique for mounting chip parts such as driver ICs and LED elements on a circuit board, there is a wide range of flip chip mounting methods using an anisotropic conductive film formed by dispersing conductive particles in an epoxy adhesive and forming a film. It has been adopted (Patent Document 1). According to this method, the electrical connection between the chip component and the circuit board is achieved by the conductive particles in the anisotropic conductive film, and at the same time, the fixing of the chip component to the circuit board is achieved by the epoxy adhesive. Therefore, the connection process is short and high production efficiency can be realized.

Patent No. 3342703

  However, chip parts are mounted on a circuit board with an anisotropic conductive film using an epoxy adhesive, and the resulting mounted product is subjected to a lead-free solder compatible reflow test, thermal shock test (TCT), and high temperature and high humidity test. When a reliability test such as a pressure cooker test (PCT) is performed, an internal stress is generated based on a difference in thermal expansion coefficient between the circuit board and the chip, and a conduction resistance value between the chip and the circuit board increases. In addition, there is an increased possibility that a problem that the chip component is peeled off from the circuit board occurs. This problem is no exception in LED devices that have recently attracted attention as energy-saving lighting materials.

  SUMMARY OF THE INVENTION An object of the present invention is to solve the above-described problems of the prior art, and lead-free solder for a mounted product obtained by mounting a chip component on a circuit board using an anisotropic conductive adhesive. Even when a reliability test involving heating of mounted products such as a compatible reflow test, thermal shock test (TCT), high temperature and high humidity test, pressure cooker test (PCT), etc., is performed between the circuit board and the chip component. It is another object of the present invention to maintain high conduction reliability and to maintain good adhesion between them and a cured anisotropic conductive adhesive.

  In order to relieve internal stress generated in each of a cured product of a circuit board, a chip component and an anisotropic conductive adhesive during a reliability test with heating such as a solder reflow test, the present inventors When the elastic modulus of the cured product of the conductive adhesive was lowered, there was a problem that the conduction reliability was greatly reduced, although it seems effective to reduce the internal stress if the elastic modulus is simply lowered. Under such circumstances, unexpectedly, there is a close relationship between the elastic modulus profile pattern of the curve obtained by plotting the elastic modulus against temperature in the figure and the reliability evaluation result of the anisotropic conductive adhesive The present invention was completed by finding that the relationship can be reduced to several relational expressions.

That is, the present invention is an anisotropic conductive adhesive in which conductive particles are dispersed in an epoxy adhesive containing an epoxy compound and a curing agent, and the cured product has a temperature of 35 ° C, 55 ° C, 95 ° C and 150 ° C. EM ³⁵ , EM ⁵⁵ , EM ⁹⁵ and EM ¹⁵⁰ are the elastic moduli in each of these, and the elastic modulus change rate between 55 ° C. and 95 ° C. is ΔEM ^55-95 , and the elastic modulus change between 95 ° C. and 150 ° C. An anisotropic conductive adhesive satisfying the following mathematical formulas (1) to (5) when the rate is ΔEM ^95-150 . Here, the elastic modulus change rate ΔEM55-95 and ΔEM ^95-150 is specifically defined respectively by the following equations (6) and (7).

  In addition, the elasticity modulus in this invention is a numerical value measured based on JISK7244-4. Specifically, it is measured using a dynamic viscoelasticity measuring instrument (for example, DDV-01FP-W, A & D) under the conditions of a tensile mode, a frequency of 11 Hz, and a heating rate of 5 ° C./min. .

  The present invention also provides a connection structure in which a chip component is flip-chip mounted on a circuit board using the above-described anisotropic conductive adhesive.

  In the anisotropic conductive adhesive of the present invention, the elastic modulus of the cured product satisfies the formulas (1) to (5). Therefore, lead-free solder compatible reflow test, thermal shock test (TCT), high temperature and high humidity test, pressure cooker for mounted products obtained by mounting chip parts on circuit board with anisotropic conductive adhesive of the present invention Even when a reliability test involving heating of a mounted product such as a test (PCT) is performed, high conduction reliability is maintained between the circuit board and the chip component, and the anisotropic conductivity cured with them is maintained. Adhesiveness with the adhesive can be maintained in a good state.

FIG. 1 is a view showing an elastic modulus profile with respect to temperature of a cured product of the anisotropic conductive adhesive of the present invention. FIG. 2 is a diagram showing an elastic modulus profile with respect to the temperature of a cured product of a conventional anisotropic conductive adhesive.

The anisotropic conductive adhesive of the present invention is one in which conductive particles are dispersed in an epoxy adhesive containing an epoxy compound and a curing agent. The cured product has a temperature of 35 ° C, 55 ° C, 95 ° C and 150 ° C. The elastic modulus in each is EM ³⁵ , EM ⁵⁵ , EM ⁹⁵ and EM ^150, and the elastic modulus change rate between 55 ° C. and 95 ° C. is ΔEM ^55-95 , and the elastic modulus change rate between 95 ° C. and 150 ° C. Is ΔEM ^95-150 , the above-described mathematical expressions (1) to (5) are satisfied.

  An example of an elastic modulus profile that satisfies these equations (1) to (5) is shown in FIG. 1 (the vertical axis is the elastic modulus and the horizontal axis is the temperature). An example of the elastic modulus profile of a conventional anisotropic conductive adhesive is shown in FIG. Since the conventional anisotropic conductive adhesive of FIG. 2 does not contain a predetermined polymer compound, the elastic modulus hardly changes even if the temperature is raised to some extent. However, if the temperature exceeds a certain temperature, the glass transition temperature is increased. In order to exceed, there exists a tendency for an elasticity modulus to fall large sharply.

  The significance of the above mathematical formulas (1) to (5) that define the anisotropic conductive adhesive of the present invention will be described in detail below.

Formula (1) has shown that the elastic modulus in 35 degreeC of the hardened | cured material of an anisotropic conductive adhesive exists in the range of 700 MPa-3000 MPa. Here, the reason why the temperature of “35 ° C.” is adopted is that, generally, when the elastic modulus change of the cured epoxy resin is less than 35 ° C., the change is relatively small and can be ignored. Is meaningful. Further, when the elastic modulus EM ^{35 at} 35 ° C. is less than 700 MPa, there is a problem in initial conduction reliability, and when it exceeds 3000 MPa, there is an increased tendency to cause a problem in conduction reliability after the moisture absorption reflow test.

  Formula (2) shows that the elastic modulus of the cured product of the anisotropic conductive adhesive decreases as the temperature increases to 35 ° C., 55 ° C., 95 ° C., and 150 ° C. When the elastic modulus does not decrease as the temperature increases, the internal stress of the adhesive (cured product) increases due to the increase in temperature, and as a result, the tendency for problems such as a decrease in adhesive strength and a decrease in conduction reliability increases. . Here, the temperature of 150 ° C. has a meaning of being a temperature at which the anisotropic conductive adhesive is heated at the time of solder reflow, in addition to being equivalent to the temperature at the time of light emission of the LED device. The reason for measuring the elastic modulus at two points of 55 ° C. and 95 ° C. between 35 ° C. and 150 ° C. is 55 ° C. when focusing on the relationship between the effect of the present invention and the elastic modulus reduction rate. This is because it was proved experimentally appropriate to use the value of the elastic modulus measured at two points of 95 ° C.

Equation (3) shows that a large elastic modulus change rate .DELTA.Em ^95-150 between 95 ° C. and 0.99 ° C. than the elastic modulus change rate .DELTA.Em ^55-95 between 55 ° C. and 95 ° C.. If the two are equal, the internal stress relaxation becomes insufficient, and if this relationship is reversed, the tendency that the conduction reliability cannot be maintained increases.

Formula (4) has shown that elastic modulus change rate ( ^DELTA) EM ^55-95 between 55 degreeC and 95 ^degreeC is 20% or more. If it is less than 20%, the tendency that conduction reliability cannot be maintained increases. Moreover, Formula (5) has shown that elastic modulus change rate ( ^DELTA) EM ^95-150 between 95 degreeC and 150 ^degreeC is 40% or more. If it is less than 40%, the tendency that the conduction reliability cannot be maintained increases. In addition, the preferable range of (DELTA ⁾ EM55-95 and (DELTA) ^EM95-150 becomes the following formula ^| equation (4 ') and (5').

  Next, specific components of the anisotropic conductive adhesive of the present invention having the characteristics of the elastic modulus of the cured product described above will be described. As described above, the anisotropic conductive adhesive of the present invention is obtained by dispersing conductive particles in an epoxy adhesive containing an epoxy compound and a curing agent.

  Preferred examples of the epoxy compound include compounds or resins having two or more epoxy groups in the molecule. These may be liquid or solid. Specifically, bisphenol A, bisphenol F, bisphenol S, hexahydrobisphenol A, tetramethylbisphenol A, diaryl bisphenol A, hydroquinone, catechol, resorcin, cresol, tetrabromobisphenol A, trihydroxybiphenyl, benzophenone, bisresorcinol, Glycidyl ether obtained by reacting polychlorophenol such as bisphenol hexafluoroacetone, tetramethylbisphenol A, tetramethylbisphenol F, tris (hydroxyphenyl) methane, bixylenol, phenol novolak, cresol novolak and epichlorohydrin; glycerin, neo Pentyl glycol, ethylene glycol, propylene glycol, butylene glycol Polyglycidyl ether obtained by reacting an aliphatic polyhydric alcohol such as hexylene glycol, polyethylene glycol or polypropylene glycol with epichlorohydrin; hydroxycarboxylic acid such as p-oxybenzoic acid or β-oxynaphthoic acid and epichlorohydrin Glycidyl ether ester obtained by reacting with phthalic acid; phthalic acid, methylphthalic acid, isophthalic acid, terephthalic acid, tetrahydrophthalic acid, hexahydrophthalic acid, endomethylenetetrahydrophthalic acid, endomethylenehexahydrophthalic acid, trimellitic acid Polyglycidyl esters obtained from polycarboxylic acids such as polymerized fatty acids; aminophenols, glycidylaminoglycidyl ethers obtained from aminoalkylphenols; Glycidylaminoglycidyl ester obtained from perfume acid; obtained from aniline, toluidine, tribromoaniline, xylylenediamine, diaminocyclohexane, bisaminomethylcyclohexane, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenylsulfone, etc. Glycidylamine; well-known epoxy resins such as epoxidized polyolefin may be mentioned.

  Among these, the alicyclic epoxy compound which can ensure the light transmittance suitable for mounting of an LED element etc. to hardened | cured material can be used preferably. Specifically, hydrogenated product of glycidyl bisphenol A (glycidyl hexahydrobisphenol A), 3,4-epoxycyclohexenylmethyl-3 ', 4'-epoxycyclohexene carboxylate, tris (2,3-epoxypropyl) isocyanate Nurate (TEPIC) is mentioned.

  As a hardening | curing agent, a well-known thing can be used as a hardening | curing agent of an epoxy compound, and it may be latent. For example, an acid anhydride curing agent, an amine curing agent, an imidazole curing agent, and the like can be used. Especially, the alicyclic acid anhydride type hardening | curing agent which can ensure the light transmittance suitable for mounting of the LED element of hardened | cured material etc. can be used preferably. Specific examples include methylhexahydrophthalic anhydride.

  The amount of the epoxy compound and curing agent used in the epoxy adhesive increases the amount of uncured epoxy compound if the curing agent is too little, and if it is too much, the excess material will cause corrosion of the adherend material. Since it tends to be accelerated, the curing agent is preferably used in an amount of 80 to 120 parts by mass, more preferably 95 to 105 parts by mass with respect to 100 parts by mass of the epoxy compound.

  In the present invention, the epoxy adhesive preferably contains a polymer compound for the purpose of relaxing internal stress in addition to the epoxy compound and the curing agent. As such a polymer compound, since the internal stress relaxation effect is reduced if the weight average molecular weight is too small or too large, a compound having a molecular weight of preferably 5,000 to 200,000, more preferably 10,000 to 100,000 is used. In addition, if the glass transition temperature is too high, the internal stress relaxation effect is reduced, so that the glass transition temperature is preferably 50 ° C. or lower, more preferably −30 to 10 ° C.

  Specific examples of such a polymer compound include acrylic resin, rubber (NBR, SBR, NR, SIS or hydrogenated product thereof), olefin resin, and the like. These polymer compounds preferably have a functional group such as a glycidyl group or an amino group. Preferable polymer compounds include acrylic resins from the viewpoint of showing good heat resistance characteristics. Specific examples of the acrylic resin include a copolymer of (meth) acrylic acid alkyl ester having 2 to 8 carbon atoms, preferably 4 to 8 and glycidyl (meth) acrylate or dialkylaminoalkyl (meth) acrylate. be able to. Here, as preferable C2-C8 alkyl ester of (meth) acrylic acid, ethyl acrylate, butyl acrylate, or 2-ethylhexyl acrylate can be mentioned, and preferable glycidyl (meth) acrylate is glycidyl methacrylate. Preferred dialkylaminoalkyl (meth) acrylates include diethylaminoethyl acrylate.

  Among the acrylic resins composed of such components, preferred are 10 to 100 parts by mass, preferably 10 to 40 parts by mass, of glycidyl methacrylate or diethylaminoethyl acrylate with respect to 100 parts by mass of ethyl acrylate, butyl acrylate or 2-ethylhexyl acrylate. Examples thereof include those obtained by copolymerization. In particular, a copolymer obtained by copolymerizing 10 to 100 parts by mass, preferably 10 to 40 parts by mass of glycidyl methacrylate with respect to 100 parts by mass of butyl acrylate is preferable because it has an advantage that the silver wiring and the silver electrode are hardly corroded.

  If the amount of such a polymer compound used in an epoxy adhesive is too small, the internal stress relaxation effect is small, and if it is too large, there is a tendency that the conduction reliability cannot be maintained. Preferably it is 10-50 mass parts with respect to a total of 100 mass parts with a compound, More preferably, it is 10-30 mass parts.

  An imidazole compound can further be mix | blended with an epoxy-type adhesive agent as a hardening accelerator as needed. Specific examples of the imidazole compound include 2-methyl-4-ethylimidazole. If the amount of the imidazole compound used is too small, the amount of uncured components increases, and if it is too large, the corrosion of the adherend material tends to be accelerated by the influence of the excess curing accelerator. On the other hand, it is preferably 0.01 to 10 parts by mass, more preferably 0.1 to 5 parts by mass.

  As the conductive particles constituting the epoxy adhesive, conductive particles conventionally used in anisotropic conductive adhesives can be used. For example, metal particles such as gold, nickel and solder, plated metal-coated particles of resin particles, particles coated with an insulating thin film, and the like can be used as appropriate. The particle diameter of the conductive particles is usually 3 to 10 μm, similarly to the conventional conductive particles. Such conductive particles are preferably 1 to 100 parts by mass, more preferably 10 to 50 parts by mass with respect to 100 parts by mass of the epoxy adhesive in order to ensure good anisotropic conductivity and conduction reliability. Part.

  In the anisotropic conductive adhesive of the present invention, various additives that are also used in conventional anisotropic conductive adhesives can be blended as necessary. For example, a silane coupling agent, a filler, an ultraviolet absorber, an antioxidant and the like can be blended.

  The anisotropic conductive adhesive of the present invention can be produced by uniformly dispersing conductive particles in an epoxy adhesive according to a conventional method. In that case, it can process into forms, such as a paste form, a film form, and a highly viscous liquid form, according to a conventional method. Moreover, this anisotropic conductive adhesive is a thermosetting type, and can be hardened normally by heating to 150-250 degreeC.

  The anisotropic conductive adhesive of the present invention can be preferably used when connecting chip components and various modules to a circuit board. In particular, a connection structure in which chip parts such as IC chips and LED elements are flip-chip mounted on a circuit board using the anisotropic conductive adhesive of the present invention is a reflow test corresponding to lead-free solder, a thermal shock test (TCT). Even when a reliability test involving heating of a mounted product such as a high-temperature and high-humidity test or a pressure cooker test (PCT) is performed, high conduction reliability is maintained between the circuit board and the chip component. The adhesiveness between them and the cured anisotropic conductive adhesive is maintained in a good state.

Hereinafter, the present invention will be specifically described by way of examples.

Reference Example 1 (Production of acrylic resin A)
A four-necked flask equipped with a stirrer and a condenser is charged with 100 g of ethyl acrylate (EA), 10 g of glycidyl methacrylate (GMA), 0.2 g of azobisbutyronitrile, 300 g of ethyl acetate, and 5 g of acetone while stirring. The polymerization reaction was carried out at 0 ° C. for 8 hours. The precipitated particles were collected by filtration, washed with ethanol, and dried to obtain acrylic resin A. The resulting acrylic resin A had a weight average molecular weight of 80000 and a glass transition temperature of −40 ° C.

Reference Example 2 (Production of acrylic resin B)
A four-necked flask equipped with a stirrer and a condenser is charged with 100 g of ethyl acrylate (EA), 10 g of dimethylaminoethyl acrylate (DMAEA), 0.2 g of azobisbutyronitrile, 300 g of ethyl acetate, and 5 g of acetone and stirred. The polymerization reaction was carried out at 70 ° C. for 8 hours. The precipitated particles were collected by filtration, washed with ethanol and dried to obtain acrylic resin B. The resulting acrylic resin B had a weight average molecular weight of 80000 and a glass transition temperature of 18 ° C.

Reference Example 3 (Production of acrylic resin C)
A four-necked flask equipped with a stirrer and a condenser is charged with 100 g of butyl acrylate (BA), 10 g of glycidyl methacrylate (GMA), 0.2 g of azobisbutyronitrile, 300 g of ethyl acetate, and 5 g of acetone while stirring. The polymerization reaction was carried out at 0 ° C. for 8 hours. The precipitated particles were collected by filtration, washed with ethanol and dried to obtain acrylic resin C. The resulting acrylic resin C had a weight average molecular weight of 80000 and a glass transition temperature of -70 ° C.

Reference Example 4 (Production of acrylic resin D)
A four-necked flask equipped with a stirrer and a condenser is charged with 100 g of 2-ethylhexyl acrylate (2EHA), 10 g of glycidyl methacrylate (GMA), 0.2 g of azobisbutyronitrile, 300 g of ethyl acetate, and 5 g of acetone and stirred. The polymerization reaction was carried out at 70 ° C. for 8 hours. The precipitated particles were collected by filtration, washed with ethanol and dried to obtain acrylic resin D. The obtained acrylic resin D had a weight average molecular weight of 80000 and a glass transition temperature of -69 ° C.

Examples 1-6, Comparative Examples 1-5
An anisotropic conductive adhesive was prepared by uniformly mixing the components shown in Table 1 with a planetary stirrer.

Evaluation Test As described below, the adhesive strength, elastic modulus, and conduction reliability of the pasty anisotropic conductive adhesives obtained in Examples 1 to 6 and Comparative Examples 1 to 5 were measured.

<Adhesion test>
A paste-like anisotropic conductive adhesive is applied to a glass epoxy circuit board having a Cu wiring portion subjected to Au flash plating to a thickness of 25 μm (dry thickness), and a 1.5 mm square IC chip is formed thereon. And a thermocompression bonding by heating to 180 ° C. for 30 seconds with a flip chip bonder to obtain a connection structure. Immediately after being obtained (initial), after reflowing (260 ° C.), the IC chip of the connection structure after being left at 150 ° C. for 100 hours was bonded using a die shear tester (Bond Tester PTR 1100, Reska Co.). (Chip) was measured. The obtained results are shown in Table 1. When the conditions for this adhesion test are assumed, it is practically desirable that the adhesion is 50 N / chip or more.

<Elastic modulus measurement>
The anisotropic conductive adhesive was applied on the release-treated PET so as to have a dry thickness of 80 μm, and cured by being put in a furnace at 150 ° C. The cured product was peeled off from the peel-treated PET, and was cut into strips having a length of 3.5 cm and a width of 0.4 cm to prepare a sample. Tensile modulus (EM ³⁵ , EM ⁵⁵ , EM ⁹⁵ , EM ¹⁵⁰ ) at 35 ° C., 55 ° C., 95 ° C. and 150 ° C. of the sample was measured by a dynamic viscoelasticity measuring device (DDV-01FP-W, A & D): Tensile Mode, frequency 11 Hz, temperature rising rate 5 ° C./min). Moreover, the elastic modulus change rate (( ^DELTA ) EM55-95, ( ^DELTA ) ^EM95-150 ) was computed from the obtained result according to Formula (6) and (7). The obtained results are shown in Table 1.

<Conduction reliability test>
A paste-like anisotropic conductive adhesive is applied to a glass epoxy circuit board having a Cu wiring portion subjected to Au flash plating so as to have a thickness of 25 μm (dry thickness), and a 6.3 mm square IC chip is formed thereon. And thermocompression-bonded by heating to 180 ° C. for 30 seconds with a flip chip bonder. The conduction resistance of the connection structure immediately after being obtained was measured by a four-terminal method. Thereafter, the level 4 moisture absorption reflow test (moisture absorption conditions: 30 ° C., 60% RH for 96 hours, reflow conditions reflow peak temperature 260 ° C.) or level 2 moisture absorption reflow test (moisture absorption) Conditions: 85 ° C., 60% RH, left for 168 hours, reflow condition: reflow peak temperature 260 ° C.), and the conduction resistance was measured. After this measurement, the connection structure was subjected to a thermal shock test (TCT: −55 ° C., 0.5 hour ← → 125 ° C., 0.5 hour, 500 cycles), and the conduction resistance was measured again. When the conduction resistance value was less than 1Ω, it was evaluated as good (G), and when it was 1Ω or more, it was evaluated as defective (NG). The obtained results are shown in Table 1.

  As can be seen from Table 1, the anisotropic conductive adhesives of Examples 1 to 6 whose elastic modulus satisfies the following mathematical formulas (1) to (5) have an initial adhesive strength of 150 ° C. for 100 hours after reflow. Good results were shown in each after the course. The conduction reliability also showed good results at the beginning, after level 4 moisture absorption reflow, after level 2 moisture absorption reflow, and after 500 cycles of thermal shock. The anisotropic conductive adhesive of Example 5 using a polymer compound obtained by reacting acrylic resin C and glycidyl methacrylate is more anisotropic than the anisotropic conductive adhesives of other examples. Corrosion of the silver wiring and silver electrode of the conductive conductive connection portion could be prevented.

On the other hand, in the case of Comparative Example 1, since EM ³⁵ exceeded 3000 MPa, Formula (1) was not satisfied, and Formulas (3) to (5) were not satisfied. As for the conduction reliability, the expected conduction reliability could not be achieved after the moisture absorption reflow test under more severe conditions.

In the case of Comparative Example 2, the EM ³⁵ is less than 700 MPa and does not satisfy the formula (1). Therefore, the adhesive strength was not obtained after leaving at 150 ° C. for 100 hours, but the conduction reliability was The expected characteristics were not obtained immediately after the connection structure was created.

In the case of Comparative Example 3, since the elastic modulus change rate ΔEM ^55-95 is less than 20% and does not satisfy the formula (4), the adhesive strength is expected after reflowing and after standing at 150 ° C. for 100 hours. It was not obtained. Regarding the conduction reliability, the expected conduction reliability could not be achieved after the moisture absorption reflow test under more severe conditions.

In the case of Comparative Example 4, the elastic modulus change rate ΔEM ^55-95 is less than 20%, ΔEM ^95-150 is also less than 40%, and does not satisfy the expressions (4) and (5). The desired characteristics were not obtained after reflow and after standing at 150 ° C. for 100 hours. Regarding the conduction reliability, the expected conduction reliability could not be achieved after the moisture absorption reflow test under more severe conditions.

In the case of Comparative Example 5, since the elastic modulus change rate ΔEM ^95-150 is less than 40 and does not satisfy the formula (5), the adhesive strength is obtained after reflowing and after standing at 150 ° C. for 100 hours. I couldn't. Regarding the conduction reliability, the expected conduction reliability could not be achieved after the moisture absorption reflow test under more severe conditions.

  In the anisotropic conductive adhesive of the present invention, the elastic modulus of the cured product satisfies the formulas (1) to (5). Therefore, lead-free solder compatible reflow test, thermal shock test (TCT), high temperature and high humidity test, pressure cooker for mounted products obtained by mounting chip parts on circuit board with anisotropic conductive adhesive of the present invention Even when a reliability test involving heating of a mounted product such as a test (PCT) is performed, high conduction reliability is maintained between the circuit board and the chip component, and the anisotropic conductivity cured with them is maintained. Adhesiveness with the adhesive can be maintained in a good state. Therefore, the anisotropic conductive adhesive of the present invention is useful for connection between a circuit board and various electronic components such as chip parts, modules, and flexible circuit boards.

Claims (10)

(Meth) acrylic acid having 2 to 8 carbon atoms and a glycidyl (meth) acrylate or dialkylaminoalkyl (meth) acrylate copolymer having a weight average molecular weight of 5,000 to 200,000 and a glass transition temperature of 50 ° C. or less. containing a polymer compound, hydrogenated product of glycidyl bisphenol a epoxy compound, or 3,4-epoxycyclohexenylmethyl-3 ', 4'-epoxy cyclohexene carboxylate, and methylhexahydrophthalic anhydride as the curing agent An anisotropic conductive adhesive in which conductive particles are dispersed in an epoxy adhesive, and the elastic modulus of each of the cured product at 35 ° C., 55 ° C., 95 ° C. and 150 ° C. is EM ³⁵ , EM ⁵⁵ , EM ^95. and the ^{EM 0.99,} the elastic modulus change rate between 55 ° C. and 9 5 ° C. delta M ^55-95, 95 ° C. and when the elastic modulus change rate was .DELTA.Em ^95-150, the following equation (1) to an anisotropic conductive adhesive which satisfies (5) between 0.99 ° C..

An acrylic resin having a weight average molecular weight of 5,000 to 200,000 and a glass transition temperature of 50 ° C. or less, obtained by copolymerizing 10 to 100 parts by mass of glycidyl methacrylate or diethylaminoethyl acrylate with respect to 100 parts by mass of ethyl acrylate, butyl acrylate or 2-ethylhexyl acrylate A polymer compound, a hydrogenated product of glycidyl bisphenol A or 3,4-epoxycyclohexenylmethyl-3 ', 4'-epoxycyclohexene carboxylate as an epoxy compound, and methylhexahydrophthalic anhydride as a curing agent. a anisotropic conductive adhesive conductive particles dispersed in an epoxy adhesive containing, 35 ° C. of the cured product, 55 ° C., the elastic modulus in each of 95 ° C. and ^{150 ℃ EM 35, EM 55,} EM ⁹⁵ and And M ^0.99, the elastic modulus change rate between 55 ° C. and 95 ° C. .DELTA.Em ^55-95, the elastic modulus change rate between 95 ° C. and 0.99 ° C. when the ΔEM ^95-150, the following equation ( An anisotropic conductive adhesive satisfying 1) to (5).

A polymer compound, which is an acrylic resin having a weight average molecular weight of 5,000 to 200,000 and a glass transition temperature of 50 ° C. or lower, obtained by copolymerizing 10 to 100 parts by mass of glycidyl methacrylate with 100 parts by mass of butyl acrylate, and glycidyl bisphenol A as an epoxy compound Conductive particles dispersed in an epoxy adhesive containing hydrogenated product or 3,4-epoxycyclohexenylmethyl-3 ', 4'-epoxycyclohexenecarboxylate and methylhexahydrophthalic anhydride as a curing agent It is an isotropic conductive adhesive, and the cured product has an elastic modulus at 35 ° C., 55 ° C., 95 ° C. and 150 ° C., respectively, EM ³⁵ , EM ⁵⁵ , EM ⁹⁵ and EM ¹⁵⁰ . Elastic modulus change rate between ΔEM ^55-95 , between 95 ° C and 150 ° C An anisotropic conductive adhesive satisfying the following mathematical formulas (1) to (5) when the elastic modulus change rate is ΔEM ^95-150 .

The anisotropic conductive adhesive according to claim 1, wherein the elastic modulus change rates ΔEM ^55-95 and ΔEM ^95-150 satisfy the expressions (4 ′) and (5 ′), respectively.

The anisotropic conductive adhesive according to any one of claims 1 to 4 , wherein the epoxy adhesive contains 80 to 120 parts by mass of a curing agent with respect to 100 parts by mass of the epoxy compound. The amount of polymer compound in the epoxy adhesive, the total 100 parts by weight of epoxy compound and curing agent and the polymer compound, different according to any one of claims 1 to 5, 10 to 50 parts by weight Isotropic conductive adhesive. The anisotropic conductive adhesive according to any one of claims 1 to 6 , further comprising 0.01 to 10 parts by mass of 2-methyl-4-ethylimidazole as a curing accelerator with respect to 100 parts by mass of the curing agent. The anisotropic conductive adhesive according to any one of claims 1 to 7 , comprising 1 to 100 parts by mass of conductive particles with respect to 100 parts by mass of the epoxy adhesive. A connection structure in which a chip component is flip-chip mounted on a circuit board using the anisotropic conductive adhesive according to any one of claims 1 to 8 . The connection structure according to claim 9 , wherein the chip component is an LED element.

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