KR20120023554A - Adhesive for connecting counter electrodes - Google Patents

Abstract

PURPOSE: An adhesive for connecting counter electrodes is provided to have relatively low hardening temperature, high connection reliability, and good storage stability. CONSTITUTION: An adhesive for connecting counter electrodes comprises: a binder resin containing 100.0 parts by weight of a (meth)acrylate compound, and an epoxy resin of which average molecular weight is 5,000-70,000; 0.1-5 parts by weight of an imidazole based hardener; 0.1-10 parts by weight of an organic peroxide; and 0.5-3 parts by weight of water. The binder resin contains 70-95 weight% of the (math)acrylate compound, and 5-30 weight% of the epoxy resin of which average molecular weight is 5,000-70,000. The DSC exothermic peak temperature of the adhesive is 70-100 °C, and the viscosity at 25 °C. Is 10-50 Pa·s.

Description

Adhesive for connecting counter electrodes

This invention relates to the contact structure with which the counter electrode is connected by the adhesive agent for opposing electrode connections, and its hardened | cured material, and its manufacturing method.

As the wiring board of the disposable IC tag attracting attention recently, the polyester film wiring board which arrange | positioned the aluminum wiring circuit on the polyester film rather than a polyimide film from the cost point of view became the mainstream. By the way, since a polyester film is inferior in heat resistance compared with a polyimide film, the thermosetting property used when connecting the connection terminal of a polyester film wiring board, and the connection terminal of an IC chip and a flexible printed circuit film which opposes it is As the adhesive for the opposite electrode connection, the curing temperature is relatively low, and from the standpoint of handling, the state at room temperature is a paste or a film, and high connection reliability is required.

Conventionally, the one-component epoxy adhesive which used the imidazole series hardening | curing agent together with the epoxy resin was widely used as an adhesive agent for the opposite electrode connection of the IC tag, but connection reliability is enough, but it can be said that low temperature fast hardenability is enough. There was no. Therefore, in recent years, it is proposed to mix | blend the radically polymerizable (meth) acrylate compound and the organic peroxide which is a radical polymerization initiator with a one-component adhesive which has an epoxy resin as a main component (patent document 1). According to this technique, it can be expected that its low temperature fast curing property is improved without compromising the advantages of the one-component epoxy adhesive.

Japanese Patent Laid-Open No. 2001-323246

However, since the organic peroxide decomposes gradually even at room temperature, there is a problem that the storage stability of the one-component adhesive in which it is blended is lowered.

SUMMARY OF THE INVENTION An object of the present invention is to solve the problems of the prior art described above, and comprises a counterpart electrode formed by mixing a one-component epoxy adhesive with a radically polymerizable (meth) acrylate compound capable of low temperature rapid curing and an organic peroxide that is a radical polymerization initiator. It aims at providing comparatively low hardening temperature and high connection reliability with respect to the adhesive agent for connection, and providing favorable storage stability.

MEANS TO SOLVE THE PROBLEM This inventor shows the comparatively low hardening temperature of the adhesive agent which mix | blended imidazole series hardening | curing agent and organic peroxide in binder resin containing mainly (meth) acrylate compound and the epoxy resin of a specific molecular weight in specific range, and shows high connection reliability. I found something that could be realized. In addition, the present inventors have to exclude water from the adhesive in a common sense under the recognition that the adhesive is a non-aqueous type adhesive unlike the emulsion adhesive. It has also been found that it is possible to improve the storage stability of the adhesive without compromising this advantage. This inventor came to complete this invention based on these knowledge.

That is, the present invention provides the following components (a) to (d):

Component (a): binder resin containing (meth) acrylate compound (a1) and an epoxy resin (a2) having a weight average molecular weight of 5000 to 70000;

Component (b): 0.1 to 5 parts by mass of an imidazole series curing agent based on 100 parts by mass of component (a);

Component (c): 1 to 10 parts by mass of organic peroxide per 100 parts by mass of component (a); And

Component (d): 0.5 to 3 parts by mass of water based on 100 parts by mass of component (a)

The adhesive for opposing electrode connection containing this is provided. Here, the binder resin of component (a) preferably contains 70 to 95 mass% of (meth) acrylate compound (a1) and 5 to 30 mass% of epoxy resin (a2) having a weight average molecular weight of 5000 to 70000. .

Moreover, this invention is for the counter electrode connection mentioned above between the said 1st connection terminal of the 1st wiring circuit body which has a 1st connection terminal, and the said 2nd connection terminal of the 2nd wiring circuit body which has a 2nd connection terminal. The first connecting terminal and the second connecting terminal are electrically connected by sandwiching an adhesive and applying heat and pressure to the second wiring circuit body so that the opposite electrode connecting adhesive held by the first connecting terminal and the second connecting terminal is cured. It provides a counter electrode connection method characterized by connecting.

In addition, the present invention provides a first wiring circuit assembly having a first connection terminal, a second wiring circuit assembly having a second connection terminal facing the first connection terminal, and an opposing first connection terminal and the second connection terminal. It provides the bonded structure comprised from the hardened | cured material of the adhesive agent for opposing electrode connection mentioned above which clamps on and electrically connects these.

The adhesive for opposing electrode connection of this invention mainly contains imidazole series hardening | curing agent and organic peroxide in specific amount range with respect to binder resin containing a (meth) acrylate compound and an epoxy resin of a specific molecular weight, and also a small amount of water It contains. For this reason, relatively low hardening temperature is shown, high connection reliability can be achieved, and favorable storage stability is shown. Moreover, although it is a paste form at room temperature normally, it may be a film form.

The present invention is cured by being heated and pressurized in a state sandwiched between a pair of opposing electrodes, and constitutes the following components (a) to (d) as an adhesive for opposing electrode connection for electrically connecting the opposing electrode. .

Component (a): binder resin;

Component (b): imidazole series curing agent;

Component (c): organic peroxide; And

Component (d): water.

The binder resin of component (a) mainly contains a (meth) acrylate compound (a1) and the epoxy resin (a2) of a specific molecular weight.

The (meth) acrylate compound (a1) is a component for imparting low temperature fast curing property to the adhesive for opposing electrode connection, and is a methacrylate compound and / or acrylate having a radical polymerizable unsaturated bond capable of polymerization at low temperature. Compound. Such a (meth) acrylate compound is a monofunctional (meth) acrylate compound and a polyfunctional (meth) acrylate compound (particularly a bifunctional (meth) acrylate compound and a trifunctional (meth)) in order to balance the physical properties after curing. Preferably a mixture of acrylate compounds). Here, when (meth) acrylate compound (a1) is a mixture of a monofunctional (meth) acrylate compound, a bifunctional (meth) acrylate compound, and a trifunctional (meth) acrylate compound, these three types of (meth) It is preferable that the compounding quantity of an acrylate compound in order of a monofunctional (meth) acrylate compound> a bifunctional (meth) acrylate compound> a trifunctional (meth) acrylate compound from a balance of viscosity after a compounding.

As the monofunctional (meth) acrylate compound, methyl (meth) acrylate, ethyl (meth) acrylate, n or i-propyl (meth) acrylate, n, i, sec or tert-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, benzyl (meth) acrylate, dicyclopentanyl acrylate, etc. are mentioned, Among these, dicyclopentanyl acrylate can be used preferably from a heat resistance after hardening. As a bifunctional (meth) acrylate compound, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, and propylene glycol di (meth) acrylate And dipropylene glycol di (meth) acrylate, 1,2-cyclohexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, dicyclopentadiene dimethacrylate, and the like. Dicyclopentadiene dimethacrylate can be used preferably from the heat resistance after hardening. As the trifunctional (meth) acrylate compound, glycerin tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, tris (2-acryloyloxyethyl) Isocyanurate etc. are mentioned, Especially, the tris (2-acryloyl oxyethyl) isocyanurate can be used preferably from the heat-resistance point after hardening.

When using the adhesive agent for opposing electrode connections of this invention as a paste, when there is too little content of the (meth) acrylate compound (a1) in component (a) binder resin, connection reliability will fall, and when too much, adhesive strength will fall Since it exists in the tendency to become, Preferably it is 70-95 mass%, More preferably, it is 75-90 mass%. Moreover, when using the adhesive agent for opposing electrode connections of this invention as a film, content of the (meth) acrylate compound (a1) in component (a) binder resin becomes like this. Preferably it is 30-60 mass%.

The epoxy resin (a2) is a component for imparting good connection reliability to the adhesive for the opposite electrode connection. The epoxy resin (a2) can be selected from the epoxy resins used in the conventional adhesive for the opposite electrode connection, and the weight average molecular weight is 5000 to 70000. Preferably 5500-65000 is used. This is because the adhesive strength decreases when the weight average molecular weight is less than 5000, and when the weight average molecular weight exceeds 70000, the viscosity tends to increase, which is undesirable.

As an epoxy resin used by this invention, it may be liquid or solid, and epoxy equivalent is generally about 100-4000, and it is preferable to have 2 or more epoxy groups in a molecule | numerator. As an example, a bisphenol-A epoxy compound, a phenol novolak-type epoxy compound, a cresol novolak-type epoxy compound, an ester type epoxy compound, an alicyclic epoxy compound, etc. are mentioned, for example. In addition, these compounds contain a monomer and an oligomer.

When using the adhesive agent for opposing electrode connection of this invention as a paste, since content of the epoxy resin (a2) in component (a) binder resin is too small, adhesive strength will fall, and too much, too much viscosity becomes preferable, Preferably It is 5-30 mass%, More preferably, it is 10-25 mass%. Moreover, when using the adhesive agent for opposing electrode connections of this invention as a film, content of the epoxy resin (a2) in component (a) binder resin becomes like this. Preferably it is 40-70 mass%.

The imidazole series hardening | curing agent of a component (b) is a hardening | curing agent for hardening an epoxy resin, and can use suitably selecting the imidazole series hardening | curing agent conventionally used as a hardening | curing agent for epoxy resins. As an example, the imidazole compound specified by the registered trademark "curesol" (Shikoku Kasei Kogyo Co., Ltd.), such as 2-methylimidazole and 2-ethyl-4-methylimidazole, is mentioned, for example. Moreover, about these imidazole series hardening | curing agents, it is preferable to make it latent by a well-known method for the improvement of the storage stability of the adhesive agent for opposing electrode connections. Moreover, as an imidazole series hardening | curing agent of component (b), the compound which has imidazole skeleton, for example, imidazole silane, etc. can also be used.

Content in the adhesive agent for opposing electrode connection of the imidazole series hardening | curing agent of component (b) is 0.1-5 mass parts with respect to 100 mass parts of component (a) binder resin, Preferably it is 0.5-3 mass parts. It is because connection reliability will fall when it is less than 0.1 mass part, and storage stability will fall when it exceeds 5 mass parts, and it is unpreferable.

The organic peroxide of component (c) is a compound for generating radical species for radically polymerizing the (meth) acrylate compound (a1) in component (a), which initiates radical polymerization of the (meth) acrylate compound (a1). It can select suitably from a well-known organic peroxide as a polymerization initiator for making it use. Specifically, benzoyl peroxide, di-t-butyl peroxide, dicumyl peroxide, 1,1-bis (t-butyl peroxide) 3,3,5-trimethylsiloxane, etc. are mentioned.

Content in the adhesive agent for opposing electrode connection of the organic peroxide of component (c) is 1-10 mass parts with respect to 100 mass parts of component (a) binder resin, Preferably it is 2-8 mass parts. It is because when it is less than 1 mass part, reactivity will fall, and when it exceeds 10 mass parts, storage stability will fall and it is unpreferable.

Water of component (d) is a component for improving the storage stability of the adhesive for opposing electrode connections, and ion-exchange water or distilled water can be used preferably.

Content in the adhesive agent for opposing electrode connections of the water of component (d) is 0.5-3 mass parts with respect to 100 mass parts of component (a) epoxy resins, Preferably it is 0.5-2 mass parts. It is because when it is less than 0.5 mass part, storage stability will fall, and when it exceeds 3 mass parts, it will become a cause of the space | gap after hardening and reliability will fall and it is unpreferable.

In order that the adhesive agent for opposing electrode connections of this invention which consists of the above components (a)-(d) implements low temperature fast hardening, its DSC (differential thermal analysis) exothermic peak temperature becomes like this. Preferably it is 70-100 degreeC, More preferably, Preferably 80 to 100 ° C. Here, DSC exothermic peak temperature can be measured according to the operation described in JISK1029. An example of typical measurement conditions is a temperature increase rate of 5 ° C./min. DSC measurement can be performed using a commercially available DSC apparatus (for example, DSC6200, Seiko Instruments Inc.).

Moreover, the viscosity in 25 degreeC of the counter electrode connection adhesive agent of this invention from a viewpoint of handleability and applicability becomes like this. Preferably it is 10-50 Pa.s, More preferably, it is 15-45 Pa.s. Here, a viscosity can be measured according to JIS Z8803, for example, can be measured using a rheometer (Hake Corporation).

Moreover, when the adhesive agent for opposing electrode connections of this invention is solid at a normal temperature instead of a paste form, it can film-form by the cast method and can use it as an adhesive film for opposing electrode connections.

The adhesive for opposing electrode connections of this invention can be made to contain well-known additives, such as a silane coupling agent, a coloring agent, a filler, and a preservative, as needed. Especially, as electroconductive particle for anisotropic conductive connection, it can use as an anisotropic conductive adhesive agent by mix | blending nickel particle, gold particle, nickel coating resin particle, etc. of 1-20 micrometer diameter, for example in the adhesive agent for opposing electrode connections of this invention. Become.

The adhesive agent for opposing electrode connections of this invention can be manufactured by mixing uniformly the component (a)-(d) mentioned above and an additive by a well-known mixing method as needed.

The adhesive agent for opposing electrode connections of this invention can be applied suitably to the opposing electrode connection method. Hereinafter, it demonstrates in process order.

First, the adhesive agent for opposing electrode connections of this invention is pinched | interposed between the said 1st connection terminal of the 1st wiring circuit body which has a 1st connection terminal, and the said 2nd connection terminal of the 2nd wiring circuit body which has a 2nd connection terminal. Let's do it. It does not specifically limit as a method of clamping the adhesive agent for opposing electrode connections between a 1st connection terminal and a 2nd connection terminal, A well-known method can be used. The method of using a syringe dispenser, the method of using the screen printing method, the method of using the film form, etc. are mentioned.

As a 1st wiring circuit body, a rigid wiring board, a glass wiring board, a flexible printed wiring film, etc. are mentioned. As a 1st connection terminal, Cu, Al, ITO connection pad, bump, etc. which were formed by the additive method, the semiadditive method, the subtractive method, etc. are mentioned. On the other hand, as a 2nd wiring circuit body, various electronic components, such as an IC chip, a capacitor, and a resistor, are mentioned besides the board | substrate similar to a 1st wiring circuit body. As a 2nd connection terminal, the connection terminal similar to a 1st connection terminal is mentioned.

Next, heat and pressure are applied to the second wiring circuit body so that the adhesive for the opposite electrode connection held between the first connection terminal and the second connection terminal is cured. Thereby, a 1st connection terminal and a 2nd connection terminal can be electrically connected. The application level of heat and pressure may be performed according to the characteristic of the adhesive agent for opposing electrode connections. For example, when the DSC exothermic peak of the adhesive for counter electrode connection is 70-100 degreeC, it heats normally at 100-150 degreeC. In addition, a pressure is 1-5 N / mm <2> normally.

According to the counter electrode connection method demonstrated above, the following connection structures are obtained. That is, between the 1st wiring circuit body which has a 1st connection terminal, the 2nd wiring circuit body which has a 2nd connection terminal which opposes a 1st connection terminal, and is clamped between the opposing 1st connection terminal and 2nd connection terminal, Moreover, the bonded structure comprised from the hardened | cured material of the adhesive agent for opposing electrode connections of this invention mentioned above which electrically connects these is obtained. Each component of this connection structure was as having demonstrated in the counter electrode connection method.

[Example]

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

Examples 1-20, Comparative Examples 1-4

The adhesive for opposing electrode connection was manufactured by mixing the component of Table 1 uniformly with a mixer. DSC exothermic peak temperature measurement, viscosity measurement and storage stability test of the obtained counter electrode connection adhesive agent, and the resistance value (initial stage, after aging) when the wiring board and IC chip were connected using the counter electrode connection adhesive agent are measured, And the bending test was performed as described below. The obtained results are shown in Table 1.

(DSC exothermic peak temperature measurement)

The DSC exothermic peak temperature of the adhesive for opposing electrode connections was thermally analyzed under a heating condition of 5 ° C./min using a differential thermal analysis device (DSC6200, Seiko Instruments Co., Ltd.).

It is also known that when the binder composition and the type of organic peroxide are the same, they show nearly identical DSC peaks. Therefore, it is assumed that the adhesive of Example 2 and the adhesives of Examples 13 to 20 and Comparative Examples 1 to 4 exhibit almost the same DSC peaks.

(Viscosity measurement)

The initial viscosity [Pa? S] of the adhesive for opposing electrode connections was measured under conditions of a temperature of 25 ° C. and a shear rate of 10 (1 / s) using a rheometer (Hakesa).

(Storage stability test)

After the storage stability of the adhesive for opposing electrode connection left the adhesive for opposing electrode connection for 12 hours in an oven at 40 ° C, the viscosity was measured as described above, and the case where the viscosity was less than 1.5 times the initial viscosity was good. When it is 1.5 times or more and less than 2.5 times, it evaluates as actual useable "△", and when it exceeds 2.5 times, it evaluated as defective "x".

(Resistance measurement)

IC chip (0.15 mm thick, 1.5 mm each side, 4 Au plating bumps (100 μm in length, 100 μm in width, height) on a wiring board on which 30 μm thick aluminum wiring was formed on one side of a 38 μm thick polyethylene terephthalate substrate 20 micrometers)) was mounted by thermocompression bonding (thermocompression conditions: 150 degreeC, 4 second, thrust 5N / mm <2>) through the adhesive agent for opposing electrode connections, and the bonded structure was obtained.

The initial resistance value of the obtained bonded structure was measured by the two-terminal method using a digital multimeter (Advantage), The case where the resistance value is less than 0.5 ohms is evaluated as good "(circle)", and the case where it is 0.5 ohms or more is bad. It evaluated as "x".

Furthermore, after leaving the obtained bonded structure in a very harsh environment of 500 hours under 85 ° C and 85% Rh (after aging), the resistance value (after aging) was measured as described above, and the resistance value was The case where it was 2 times or less of initial stage resistance value was evaluated as good "(circle)", and when it exceeded 2 times, it evaluated as defect "x".

Moreover, even if the resistance value evaluation after the aging of the adhesive agent for opposing electrode connection in very harsh conditions is "x", if initial resistance value evaluation is "(circle)", an application range will be limited but actual use is possible depending on a use.

(Bending test)

A rectangular connecting structure (3 cm in length and 2 cm in width) in which an IC chip is mounted in the center, and a stainless steel circumference of 10 cm in length and 2 cm in diameter whose mirror surface is finished on the inner surface are prepared. The stainless steel circumference was fixed to be horizontal. The bonded structure was passed through the stainless steel circumference so that the IC chip faced upward, and the connecting structure was reciprocated 10 times so that the lengthwise direction of the bonded structure was bent at 90 degrees while a load of 5 N was applied to each end of the bonded structure. . After completion of the reciprocating motion, the connecting structure was taken out from the stainless steel circumference, the resistance value was measured as described above, and the case where the resistance value was less than 2 times the initial resistance value was evaluated as good &quot; ○ &quot; The case was evaluated as "△" normally, and when three times or more, it evaluated as defective "x".

Example 21, Comparative Example 5

The coating material obtained by uniformly mixing the components of Table 2 with a mixer was apply | coated on a peeling film, and the adhesive agent for opposing electrode connections on a film was manufactured by drying. DSC exothermic peak temperature measurement and storage stability test of the obtained adhesive for opposing electrode connection, and resistance value (initial stage, after aging) at the time of connecting a wiring board and IC chip using the adhesive for opposing electrode connection are measured, and also bending The test was done similarly to the case of Example 1. The obtained results are shown in Table 2.

From the result of Examples 1-10 of Table 1, it turns out that the preferable compounding quantity of the (meth) acrylate compound of component (a) is 70-95 mass%. Moreover, it turns out that the preferable compounding quantity of a monofunctional, bifunctional, and trifunctional is in order of a monofunctional (meth) acrylate compound> a bifunctional (meth) acrylate compound> a trifunctional (meth) acrylate compound. It turns out that the weight average molecular weight of the epoxy resin of component (b) is 5000-70000, and the compounding quantity should be 5-30 mass%.

In addition, it is understood from the results of Examples 11 to 14 and Comparative Examples 1 and 2 that the compounding amount of the organic peroxide should be 1 to 10 parts by mass based on 100 parts by mass in total of the components (a) and (b).

From the result of Example 15, 16 and the comparative example 3, it turns out that the compounding quantity of water should be 0.5-3 mass parts with respect to a total of 100 mass parts of components (a) and (b).

From the result of Examples 17-20 and the comparative example 4, it turns out that the compounding quantity of the imidazole series hardening | curing agent should be 0.1-5 mass parts with respect to a total of 100 mass parts of components (a) and (b).

Moreover, from the result of Example 16 and Comparative Example 11 of Table 2, also in the adhesive agent for opposing electrode connections on a film, the effect of the presence or absence of water was confirmed. That is, it was confirmed that storage stability is improved by mixing water.

The adhesive for opposing electrode connection of this invention mix | blends the radically polymerizable (meth) acrylate compound which can be quick-cured at low temperature, and the organic peroxide which is a radical polymerization initiator with 1-component epoxy adhesive, Comprising a comparatively low hardening temperature, and high connection It shows reliability and also shows good storage stability. For this reason, the adhesive agent for opposing electrode connections of this invention is useful in the case of electrically connecting the connection terminal of a wiring circuit body, and the connection terminal of another wiring circuit body which opposes it.

Claims (10)

Component (a) to (d) below:
Component (a): binder resin containing (meth) acrylate compound (a1) and an epoxy resin (a2) having a weight average molecular weight of 5000 to 70000;
Component (b): 0.1 to 5 parts by mass of an imidazole series curing agent based on 100 parts by mass of component (a);
Component (c): 1 to 10 parts by mass of organic peroxide per 100 parts by mass of component (a); And
Component (d): 0.5 to 3 parts by mass of water based on 100 parts by mass of component (a)
Adhesive for opposing electrode connection containing a. The binder resin of component (a) contains 70-95 mass% of (meth) acrylate compounds (a1), and 5-30 mass% of epoxy resins (a2) of a weight average molecular weight 5000-70000. Adhesive for opposing electrode connection to make. The binder resin of component (a) contains 30-60 mass% of (meth) acrylate compounds (a1), and 40-70 mass% of epoxy resin (a2) of the weight average molecular weights 5000-70000. Adhesive for opposing electrode connection to make. The adhesive for counter electrode connection of Claim 1 whose DSC exothermic peak temperature is 70-100 degreeC, and the viscosity in 25 degreeC is 10-50 Pa.s. The (meth) acrylate compound (a1) is a monofunctional (meth) acrylate compound, a bifunctional (meth) acrylate compound, or a trifunctional (meth) acrylate compound according to any one of claims 1 to 4. Adhesive for opposing electrode connection which is a mixture of these. The compounding quantity of a monofunctional (meth) acrylate compound, a bifunctional (meth) acrylate compound, and a trifunctional (meth) acrylate compound of Claim 5 is a polyfunctional (meth) acrylate compound> bifunctional (meth) Adhesive for opposing electrode connection in order of acrylate compound> trifunctional (meth) acrylate compound. The opposite electrode connection adhesive of Claim 1 shape | molded in the film form. The adhesive for opposing electrode connections as described in any one of Claims 1-7 which further contain the electroconductive particle for anisotropic conductive connection. The adhesive agent for opposing electrode connections of Claim 1 is pinched between the said 1st connection terminal of the 1st wiring circuit body which has a 1st connection terminal, and the said 2nd connection terminal of the 2nd wiring circuit body which has a 2nd connection terminal. To electrically connect the first connection terminal and the second connection terminal by applying heat and pressure to the second wiring circuit body so that the adhesive for the opposite electrode connection sandwiched between the first connection terminal and the second connection terminal is cured. Opposite electrode connection method characterized by the above-mentioned. The first wiring circuit body having the first connection terminal and the second wiring circuit body having the second connection terminal facing the first connection terminal are sandwiched between the first connection terminal and the second connection terminal facing each other. The bonded structure comprised from the hardened | cured material of the adhesive agent for opposing electrode connections of Claim 1 to electrically connect.