JP2015025028A - Connection material, connection structure prepared using the same and method of producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a connection material which can form an adhesion layer having high adhesiveness with respect to an anchor layer of a sensor and a protection film of a chip.SOLUTION: A preferable connection material comprises a radical polymerizable material, a lactone compound and a curing agent that generates a free radical. With respect to the radical polymerizable material of 100 pts.wt., the lactone compound of 7-40 pts.wt. is comprised.

Description

  The present invention relates to a connection material, a connection structure using the connection material, and a method for manufacturing the connection structure.

  As a circuit connection material used for manufacturing a semiconductor element or a liquid crystal display element, a thermosetting resin using an epoxy resin having high adhesiveness and high reliability is known (for example, see Patent Document 1). As a component of the thermosetting resin, a curing agent such as an epoxy resin, a phenol resin having reactivity with the epoxy resin, or a latent curing agent that accelerates the reaction between the epoxy resin and the curing agent is generally used. . The latent curing agent is an important factor that determines the curing temperature and the curing rate. Therefore, various compounds are used as the latent curing agent from the viewpoint of storage stability at room temperature and curing rate during heating.

  Further, as circuit connection materials, radical curable adhesives using acrylate derivatives and methacrylate derivatives (hereinafter collectively referred to as “(meth) acrylate derivatives”) and peroxides as radical polymerization initiators are also attracting attention. ing. In radical curing, radicals that are reactive species are rich in reactivity, so that curing at low temperature and in a short time is possible (see, for example, Patent Documents 2 and 3).

  Furthermore, touch panels are mounted on multifunctional mobile phones (smartphones) and tablet PCs, and in these, circuit connection materials are also applied to the connection between touch panel sensors and peripheral circuit members. As the base film of the touch panel sensor, an organic film made of PET (polyethylene terephthalate), PC (polycarbonate), PEN (polyethylene naphthalate), or the like has been studied and used from the viewpoint of cost reduction and weight reduction. Since these organic films have low heat resistance, circuit connection materials are required to be able to be cured at a low temperature of about 140 ° C. Therefore, it has been studied to apply the radical curing system as described above.

  As a method for forming a circuit of a touch panel sensor (hereinafter abbreviated as a sensor) on an organic film, a method of laminating a hard coat layer, an anchor layer, and a circuit layer in this order on the organic film is known. In this case, the anchor layer is exposed on the surface of a region where no circuit exists in the sensor. Therefore, when the circuit connection material is bonded to the sensor, the objects to which the circuit connection material is bonded are the circuit and the anchor layer.

  Usually, since the circuit material is a conductor, even the existing circuit connection materials as described above do not have much problem with adhesiveness. On the other hand, depending on the material of the anchor layer, the circuit connection material may be difficult to adhere. In particular, when the anchor layer is made of a material having a too high polarity such as melamine resin, there is a problem that the adhesiveness with the circuit connecting material is remarkably lowered.

  The circuit connection material is also used for bonding a chip or the like. In that case, a protective film made of silicon nitride or polyimide may be formed on the surface of the chip to which the circuit connection material is bonded. . Although the above-mentioned conventional radical-curing circuit connection material has adhesion to polyimide, there is a problem that adhesion to silicon nitride is lowered. Therefore, silicone-modified polyimide or the like is used in order to improve the adhesion to silicon nitride (Patent Documents 2 and 4). However, since circuit connection materials using silicone-modified polyimide and the like are expensive, there is a problem that they are rarely applicable industrially.

Japanese Patent Laid-Open No. 1-113480 JP 2002-203427 A International Publication No. 98/044067 JP 2003-64331 A

  The present invention has been made in view of the above-described problems of the prior art, and provides a connection material capable of forming an adhesive layer having high adhesion to an anchor layer of a sensor or a protective film of a chip. With the goal. Another object of the present invention is to provide a connection structure using such a connection material and a method for manufacturing the connection structure.

  In order to achieve the above object, the connection material of the present invention contains a radical polymerizable substance, a lactone compound, and a curing agent that generates free radicals, and the lactone compound is added in an amount of 7 to 40 weights per 100 parts by weight of the radical polymerizable substance. It is characterized by including a part.

  As described above, the connection material of the present invention contains a specific three components of a radical polymerizable substance, a lactone compound, and a curing agent that generates free radicals in combination, and a specific ratio of the lactone compound to the radical polymerizable substance. Including. Therefore, high adhesiveness can be exhibited with respect to the anchor layer made of melamine resin and the protective film made of silicon nitride. Moreover, since it can harden | cur by radical polymerization and an adhesive layer can be formed, adhesion | attachment can fully be performed also by the process at low temperature which can be applied to the element containing an organic film.

  In the connection material of the present invention, the lactone compound is preferably lactone (meth) acrylate. As a result, the adhesion to the anchor layer and the protective film is improved, and more sufficient adhesion can be achieved even at a low temperature.

  The present invention also provides a first circuit member having a first circuit electrode and a first circuit electrode formed on the first substrate, and a second circuit formed on the second substrate and the second substrate. A second circuit member having a circuit electrode and disposed opposite the first circuit member such that the second circuit electrode faces the first circuit electrode; and the first circuit member and the second circuit A connection structure which is arranged between the members and includes an adhesive layer for bonding the first circuit member and the second circuit member, wherein the adhesive layer is formed from the connection material of the present invention. Provide the body.

  In the connection structure of the present invention, since the first circuit member and the second circuit member are connected by the adhesive layer formed from the connection material of the present invention, the first and second circuit members are provided. Even if the adhesive surfaces of the first substrate and the second substrate are formed of melamine resin or silicon nitride, excellent adhesion between them and the adhesive layer can be obtained, so that the first circuit member The adhesion between the first circuit member and the second circuit member is also improved. Further, in such a connection structure, since the first circuit member and the second circuit member can be bonded to each other at a relatively low temperature, as the first substrate and the second substrate, It is possible to apply one containing an organic film.

  In the connection structure of the present invention, at least one of the first substrate and the second substrate has at least a surface facing the other of the first substrate and the second substrate made of melamine resin, silicon nitride, or silicon dioxide. It may be a thing.

  Melamine resin, silicon nitride and silicon dioxide were not highly adhesive to the conventional connection material, but the adhesive layer in the connection structure of the present invention was formed from the connection material of the present invention. Therefore, an adhesive layer having an excellent adhesive force can be formed even for these materials. Therefore, even if the surface of the first substrate or the second substrate, that is, at least one of the surfaces of the first and second circuit members other than the first and second circuit electrodes is formed of these materials. The connection structure of the present invention has excellent adhesion between the first circuit member and the second circuit member.

  In the connection structure of the present invention, at least one of the first circuit electrode and the second circuit electrode may be an Ag paste electrode, and among the first circuit electrode and the second circuit electrode. At least one of these may be a copper electrode, and at least one of the first circuit electrode and the second circuit electrode may be an ITO electrode.

  The adhesive layer in the connection structure of the present invention can exhibit high adhesion to these first and second circuit electrodes. Therefore, the connection structure of the present invention has excellent adhesiveness between the first circuit member and the second circuit member even when at least one of the first and second circuit electrodes is these electrodes. Can be a thing.

  The present invention also provides a first circuit member having a first circuit electrode and a first circuit electrode formed on the first substrate, and a second circuit formed on the second substrate and the second substrate. The connection material according to the present invention is provided between a second circuit member having a circuit electrode and disposed opposite to the first circuit member so that the second circuit electrode faces the first circuit electrode. Provided is a method for manufacturing a connection structure including a step of arranging and pressurizing to bond a first circuit member and a second circuit member.

  In such a manufacturing method of the connection structure of the present invention, since the first circuit member and the second circuit member are connected by the connection material of the present invention, for example, the first and second substrates are connected. Even if the opposing surface is formed of melamine resin or silicon nitride, the first circuit member and the second circuit member can be strongly bonded.

  According to the present invention, it is possible to form an adhesive layer capable of exhibiting high adhesiveness to the sensor anchor layer and the chip protective film, and connection is possible even at a low temperature that can be applied to an element using an organic film. It is possible to provide a connection material. It is also possible to provide a connection structure using such a connection material and a method for manufacturing the connection structure.

It is a figure which shows typically the cross-sectional structure of the connection structure of suitable embodiment.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings as necessary.

(Connection material)
First, a connection material according to a preferred embodiment will be described. The connection material of this embodiment contains a curing agent that generates free radicals, a radical polymerizable substance, and a lactone compound. This connecting material contains 7 to 40 parts by weight of a lactone compound with respect to 100 parts by weight of the radical polymerizable substance.

  The connection material of this embodiment can be used, for example, to bond two circuit members having circuit electrodes on the surface so that the respective circuit electrodes are electrically connected to each other. More specifically, the connection material of the present embodiment includes a first circuit member having a first substrate and a first circuit electrode formed on the first substrate, a second substrate, and the first substrate. A second circuit member having a second circuit electrode formed on the second substrate and disposed with respect to the first circuit member so that the second circuit electrode faces the first circuit electrode; And can be used to bond the first circuit member and the second circuit member.

  As a curing agent (hereinafter simply referred to as “curing agent”) that generates free radicals contained in the connection material of the present embodiment, a free radical is generated by being decomposed by heating, such as a peroxide compound or an azo compound. Compounds are preferred. The curing agent can be appropriately selected from them according to the intended connection temperature, connection time, and the like. 0.05-10 weight% is preferable in a connection material, and, as for the compounding quantity of a hardening | curing agent, 0.1-5 weight% is more preferable.

  The curing agent can be selected from, for example, diacyl peroxides, peroxydicarbonates, peroxyesters, peroxyketals, dialkyl peroxides, hydroperoxides, and the like.

  Diacyl peroxides include 2,4-dichlorobenzoyl peroxide, 3,5,5-trimethylhexanoyl peroxide, octanoyl peroxide, lauroyl peroxide, stearoyl peroxide, succinic peroxide, benzoyl peroxide And benzoyl peroxide.

  Peroxydicarbonates include di-n-propyl peroxydicarbonate, diisopropyl peroxydicarbonate, bis (4-t-butylcyclohexyl) peroxydicarbonate, di-2-ethoxymethoxyperoxydicarbonate, di- (2-Ethylhexylperoxy) dicarbonate, dimethoxybutylperoxydicarbonate, di (3-methyl-3-methoxybutylperoxy) dicarbonate and the like.

  Peroxyesters include 1,1,3,3-tetramethylbutylperoxyneodecanoate, 1-cyclohexyl-1-methylethylperoxyneodecanoate, t-hexylperoxyneodecanoate, t-butyl peroxypivalate, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, 2,5-dimethyl-2,5-di (2-ethylhexanoylperoxy) hexane 1-cyclohexyl-1-methylethylperoxy-2-ethylhexanate, t-hexylperoxy-2-ethylhexanoate, t-butylperoxy-2-ethylhexanoate, t-butylperoxy Isobutyrate, 1,1-bis (t-butylperoxy) cyclohexane, t-hexylperoxyisopropyl Monocarbonate, t-butylperoxy-3,5,5-trimethylhexanonate, t-butylperoxylaurate, 2,5-dimethyl-2,5-di (m-toluoylperoxy) hexane, t -Butyl peroxyisopropyl monocarbonate, t-butyl peroxy-2-ethylhexyl monocarbonate, t-hexyl peroxybenzoate, t-butyl peroxyacetate and the like.

  Peroxyketals include 1,1-bis (t-hexylperoxy) -3,3,5-trimethylcyclohexane, 1,1-bis (t-hexylperoxy) cyclohexane, 1,1-bis (t -Butylperoxy) -3,3,5-trimethylcyclohexane, 1,1- (t-butylperoxy) cyclododecane, 2,2-bis (t-butylperoxy) decane and the like.

  Dialkyl peroxides include α, α′-bis (t-butylperoxy) diisopropylbenzene, dicumyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, t- Examples thereof include butyl cumyl peroxide.

  Examples of hydroperoxides include diisopropylbenzene hydroperoxide and cumene hydroperoxide.

  These curing agents can be used alone or in combination. Moreover, what mixed the decomposition accelerator, the inhibitor, etc. with said compound may be used. Further, the curing agent may be one in which the above-mentioned compound is microencapsulated by being coated with a polyurethane-based or polyester-based polymer substance or the like. The microencapsulated curing agent is preferable because the storage stability tends to be extended.

  The radically polymerizable substance contained in the connection material of the present embodiment includes a compound whose polymerization is initiated by the free radical generated from the above-described curing agent, and includes such a compound alone or such a compound. Any of the compositions may be used. As a compound that can be polymerized by a free radical, either a monomer or an oligomer can be used, and a monomer and an oligomer can be used in combination.

  The compounds contained in the radically polymerizable substance include ethylene glycol diacrylate, diethylene glycol diacrylate, trimethylolpropane triacrylate, tetramethylolmethane tetraacrylate, 2-hydroxy-1,3-diaacryloxypropane, and 2,2-bis. [4- (Acryloxymethoxy) phenyl] propane, 2,2-bis [4- (acryloxypolyethoxy) phenyl] propane, dicyclopentenyl acrylate, tricyclodecanyl acrylate, tris (acryloyloxyethyl) isocyanurate Etc. These can be used alone or in combination.

  Moreover, the radically polymerizable substance may contain a polymerization inhibitor such as hydroquinone or methyl ether hydroquinone in addition to the above-described compound as necessary.

  Radical polymerizable substances are further polystyrene, polyethylene, polyvinyl butyral, polyvinyl formal, polyimide, polyamide, polyester, polyvinyl chloride, polyphenylene oxide, urea resin, melamine resin, phenol resin, xylene resin, epoxy resin, polyisocyanate resin, It may contain a polymer such as phenoxy resin. The inclusion of these polymers is preferable because the handling properties are improved and the stress relaxation property during curing is improved. Moreover, when a polymer has functional groups, such as a hydroxyl group, since adhesiveness improves, it is more preferable.

  The weight average molecular weight of these polymers is preferably 10,000 or more, and more preferably 10,000 or more and 1,000,000 or less. When the polymer has a suitable weight average molecular weight, the mixing property of the radical polymerizable substance and the connecting material tends to be improved.

Here, the weight average molecular weight defined in this specification refers to a weight average molecular weight obtained by performing measurement by gel permeation chromatography (GPC) and calculating using a standard polystyrene calibration curve. Say. The conditions for GPC are as follows.
[GPC conditions]
Equipment used: Hitachi L-6000 type (manufactured by Hitachi, Ltd.)
Column: Gel pack GL-R420 + Gel pack GL-R430 + Gel pack GL-440 (3 in total) (trade name, manufactured by Hitachi Chemical Co., Ltd.)
Eluent: tetrahydrofuran,
Measurement temperature: 40 ° C.
Flow rate: 1.75 ml / min,
Detector: L-3300RI (made by Hitachi, Ltd.).

  The radical polymerizable substance further contains a filler, a softener, an accelerator, an anti-aging agent, a colorant, a flame retardant, a thixotropic agent, a coupling agent, a phenol resin, a melamine resin, an isocyanate, and the like. You can also. When the radically polymerizable substance contains a filler, it is preferable because connection reliability and the like when connecting with a connection material are improved. As the filler, for example, a filler whose maximum diameter is smaller than the particle diameter of conductive particles as described later can be used. The content of the filler is preferably in the range of 5 to 60% by volume of the radical polymerizable substance. The effect of improving the connection reliability tends to saturate when the filler content is about 60% by volume. Moreover, as a coupling agent, the compound containing a vinyl group, an acryloyl group, an amino group, an epoxy group, and an isocyanate group is preferable because the adhesiveness of the connecting material can be further improved.

  Examples of the lactone compound contained in the connection material of the present embodiment include compounds having a structure in which at least a part of the hydrogen atoms in the ring portion of the lactone is substituted with a group containing a polymerizable functional group. When the lactone compound has a group containing a polymerizable functional group, when the connecting material is cured, a polymer containing a highly polar lactone group derived from the lactone compound is generated, and thereby adhesion to melamine resin and silicon nitride. Tends to be further improved.

  The lactone structure possessed by such a lactone compound is preferably a structure composed of a 5- to 6-membered lactone and a derivative thereof. It is preferable for the connecting material to contain such a lactone compound because the adhesion to glass or melamine tends to be improved. Examples of the lactone in the lactone structure portion include γ-butyrolactone, δ-valerolactone, and a lactone having a crosslinked condensed ring structure.

  Examples of the group containing a polymerizable functional group substituted with a lactone include an oxy (meth) acryloyl group. In the present specification, the acryloyl group and the methacryloyl group are collectively referred to as a (meth) acryloyl group, and the (meth) acryloyl group includes either or both of an acryloyl group and a methacryloyl group. means. In addition, the notation such as (meth) acrylate has the same meaning. When the group containing a polymerizable functional group in the lactone compound is directly bonded to the lactone ring, it is preferably bonded to the α-position or β-position with respect to the carbonyl carbon of the ester bond portion in the lactone structure. When the connection material contains such a lactone compound, it is preferable because the adhesion to glass or melamine tends to be further improved.

  As the lactone compound, a lactone (meth) acrylate compound in which a hydrogen atom of a ring portion in the lactone is substituted with an oxy (meth) acryloyl group is particularly preferable. When the lactone compound is such a lactone (meth) acrylate, even better adhesion to the melamine resin or silicon nitride can be obtained when the connection material is used for adhesion.

Suitable lactone (meth) acrylates include compounds represented by the following formulas (1-1) to (1-14).

  The content of the lactone compound is 7 to 40 parts by weight, preferably 12 to 40 parts by weight, and more preferably 15 to 30 parts by weight with respect to 100 parts by weight of the radical polymerizable substance. When the content of the lactone compound is less than 7 parts by weight, it is difficult to obtain an effect of improving adhesiveness. On the other hand, when the amount exceeds 40 parts by weight, the crosslink density becomes low, and the resistance reliability tends to deteriorate, for example, the resistance of the connecting material and the adhesive layer formed thereby tends to vary.

  The molecular weight of the lactone compound is preferably 100 or more and less than 500, and more preferably 140 or more and less than 300. When the molecular weight is less than 100, the chemical structure as the lactone compound tends not to be established stably. On the other hand, when the molecular weight of the lactone compound is 500 or more, the degree of decrease in the crosslinking density is increased, and the reliability of the adhesive layer formed of the connection material may be deteriorated.

  As the lactone compound in the present embodiment, commercially available products can be applied as they are, or disclosed in JP-A Nos. 2004-123678, 2004-2243, 2001-64325, and the like. What was synthesize | combined by the well-known method as shown can also be applied.

  The connection material of this embodiment may be composed of only the curing agent, radical polymerizable substance and lactone compound as described above, but may further contain other components as necessary. .

  First, the connection material can further contain a compound having one or more aminoxyl structures in the molecule. When the connecting material contains a compound having an aminoxyl structure, the storage stability of the connecting material tends to be further improved. Examples of the compound having an aminoxyl structure include 2,2,6,6-tetramethylpiperidine-1-oxyl, 2,2-dimethyl-6-phenylpiperidine-1-oxyl, and 2,2,6-trimethyl-6-phenyl. Piperidine-1-oxyl, 2,6-diphenylpiperidine-1-oxyl, 4-acetamido-2,2,6,6-tetramethylpiperidine-1-oxyl, 4-amino-2,2,6,6-tetra Methylpiperidine-1-oxyl, 4-carboxy-2,2,6,6-tetramethylpiperidine-1-oxyl, 3-carboxy-2,2,6,6-tetramethylpiperidine-1-oxyl, 4- ( 2-chloroacetamido) -2,2,6,6-tetramethylpiperidine-1-oxyl, 4-hydroxy-2,2,6,6-tetramethylpi Lysine-1-oxyl, 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxylbenzoate, 4- (2-iodoacetamido) -2,2,6,6-tetramethylpiperidine-1- Oxyl, 4-isothiocyanate-2,2,6,6-tetramethylpiperidine-1-oxyl, 4-isocyanate-2,2,6,6-tetramethylpiperidine-1-oxyl, 4-methoxy-2 , 2,6,6-tetramethylpiperidine-1-oxyl, 4-oxo-2,2,6,6-tetramethylpiperidine-1-oxyl, 2,2-dimethyl-6-cyclohexylpiperidine-1-oxyl, 2,6-dicyclohexylpiperidine-1-oxyl, 2,2-dimethyl-6-cyclopentylpiperidine-1-oxyl, 2,6-dicyclo Pentylpiperidine-1-oxyl, 2,2,5-trimethyl-4-phenyl-3-azahexane-3-nitrooxide, 2,2,5,5-tetramethylpyrrolidine-1-oxyl, 2,5-diphenylpyrrolidine Examples include -1-oxyl, 2,2-dimethyl-6-phenylpyrrolidine-1-oxyl, 2,2,6-trimethyl-6-phenylpyrrolidine-1-oxyl.

  Further, the connection material may further contain a thermoplastic resin. Examples of the thermoplastic resin include polyvinyl butyral resin, polyvinyl formal resin, polyamide resin, polyester resin, phenol resin, epoxy resin, phenoxy resin, polystyrene resin, xylene resin, polyurethane resin, and polyester urethane resin. The weight average molecular weight of the thermoplastic resin is preferably 10,000 or more from the viewpoint of film forming property and the like, and more preferably 10,000 or more and less than 1,000,000 from the viewpoint of mixing property. As the weight average molecular weight of the thermoplastic resin, a value measured in the same manner as the polymerization average molecular weight of the polymer that can be contained in the radical polymerizable substance can be applied.

  Among these, as the thermoplastic resin, a hydroxyl group-containing resin (for example, phenoxy resin) having a Tg (glass transition temperature) of 40 ° C. or more and a weight average molecular weight of 10,000 or more can be preferably applied. The hydroxyl group-containing resin may be modified with an epoxy group-containing elastomer or a radical polymerizable functional group. It is more preferable that the hydroxyl group-containing resin is modified with a radical polymerizable functional group because the heat resistance of the connecting material tends to be improved. Examples of the phenoxy resin include those obtained by reacting a bifunctional phenol and epihalohydrin to a high molecular weight, or by polyaddition reaction of a bifunctional epoxy resin and a bifunctional phenol.

  Furthermore, the connection material may contain a filler, a softener, an accelerator, an anti-aging agent, a colorant, a flame retardant, a thixotropic agent, a coupling agent, a phenol resin, a melamine resin, isocyanates, and the like. . For example, as a coupling agent, the compound which has at least 1 sort (s) of a vinyl group, an acryloyl group, an amino group, an epoxy group, or an isocyanate group is mentioned. When the connecting material contains these compounds as a coupling agent, the adhesion by the connecting material tends to be further improved.

  The connection material of the present embodiment may or may not contain conductive particles. Even if the connection material does not contain conductive particles, electrical connection between these circuit electrodes can be obtained if the circuit electrodes facing each other at the time of connection are brought into direct contact with each other. However, if the connection material further contains conductive particles, the electrical connection between the circuit electrodes facing each other can be more stably obtained.

  Examples of the conductive particles include metal particles such as Au, Ag, Ni, Cu, solder, and particles made of carbon. Moreover, the coated particle | grains which coat | covered the surface of transition metals, such as Ni, with noble metals, such as Au, may be sufficient. In the case of coated particles, in order to obtain a sufficient pot life of the connecting material, the surface layer is preferably made of Au, Ag, platinum group noble metals, not Au, transition metals such as Cu, and Au. Is more preferable.

  Further, as the conductive particles, after forming a conductive layer on the surface of the non-conductive particles by a method such as coating the surface of the non-conductive particles such as glass, ceramic, plastic, etc. with the conductive material as described above. Furthermore, coated particles in which the outermost layer is coated with noble metals, hot-melt metal particles, and the like can also be applied. When the conductive particles are hot-melt metal particles, the hot-melt metal particles can be deformed by heating and pressurization, so that the contact area with the circuit electrode is increased at the time of connection, thereby further improving the connection reliability. There is a tendency.

  The compounding quantity of electroconductive particle can be suitably set according to a use. For example, it is preferably in the range of 0.1 to 30 parts by volume with respect to a total of 100 parts by volume of the curing agent, radical polymerizable substance and lactone compound. If the conductive particles are excessively contained, a short circuit between adjacent circuits may easily occur. From the viewpoint of reliably preventing such a short circuit, the blending amount of the conductive particles is more preferably 0.1 to 10 parts by volume.

  Moreover, the connection material of the present embodiment may have a film shape. Since the film-like connecting material can be easily disposed between the first and second circuit members, they can be bonded more easily. In this case, the connection material may be divided into two layers, and the conductive particles may be contained only in one layer. At this time, for example, it is preferable that the content of the curing agent in the layer not including the conductive particles is smaller than the content of the layer including the conductive particles. When bonding is performed using such a connection material having a two-layer structure, the conductive particle in the adhesive layer is difficult to move because the layer including the conductive particles is cured faster than the layer including no conductive particles. This makes it difficult for the conductive particles to move in a direction perpendicular to the pressurizing direction at the time of circuit connection, so that a short circuit between adjacent circuits can be effectively prevented. Moreover, since the layer which does not contain electroconductive particle has a slow cure rate, the handleability at the time of connecting is favorable.

(Connection structure and manufacturing method thereof)
Next, an example of a connection structure and a manufacturing method thereof according to a preferred embodiment will be described.

  FIG. 1 is a diagram schematically showing a cross-sectional configuration of a connection structure according to a preferred embodiment. A connection structure 1 shown in FIG. 1 includes a first circuit member 20 having a first circuit electrode (first connection terminal) 22 formed on a first substrate 21 and a main surface 21a thereof, and a second circuit member 20. A second circuit member 30 having a second circuit electrode (second connection terminal) 32 formed on the substrate 31 and its main surface 31a, a first circuit member 20 and a second circuit member 30; And an adhesive layer 10 for adhering them. The second circuit member 30 is disposed to face the first circuit member 20 so that the second circuit electrode 32 faces the first circuit electrode 22.

  The adhesive layer 10 contains an adhesive 11 and conductive particles 7 dispersed in the adhesive 11. This adhesive layer 10 is formed from the connection material of the above-described embodiment, and is an example of an adhesive layer obtained using a connection material containing the conductive particles 7 in particular. The adhesive layer 10 is formed by a cured body of the connection material. This hardened body is mainly formed by radical polymerization of components other than the conductive particles in the connection material, particularly radical polymerizable substances. Such an adhesive layer 10 is preferably formed, for example, by connecting a connecting material between the first circuit member 20 and the second circuit member 30 and pressing in that state. .

  The first circuit electrode 22 and the second circuit electrode 32 facing each other are electrically connected to each other by contacting with each other through the conductive particles 7. On the other hand, circuit electrodes (first circuit electrodes 22 and second circuit electrodes 32) formed on the same circuit board are insulated from each other. In the connection structure, the first circuit member 20 and the second circuit member 30 are connected so that the first circuit electrode 22 and the second circuit electrode 32 facing each other can be electrically connected to each other. What is necessary is just to adhere | attach by the contact bonding layer 10. Therefore, the first circuit electrode 22 and the second circuit electrode 32 do not necessarily have to be connected via the conductive particles 7, and may be connected by, for example, direct contact with each other.

  Examples of the first substrate 21 and the second substrate 31 include substrates applied to chip components such as semiconductor chips, resistor chips, and capacitor chips, printed boards, and the like. Examples of these substrates include substrates made of inorganic materials such as semiconductors, glass and ceramics, plastic substrates, glass / epoxy substrates, and the like. Examples of the plastic substrate include a polyimide film, a polycarbonate film, and a polyester film.

  The first substrate 21 and the second substrate 31 do not necessarily have a single layer structure made of a single material, and may have a multilayer structure formed of a plurality of layers. For example, the first substrate 21 or the second substrate 31 has an anchor layer or a protective film formed on the surface on which the first circuit electrode 22 or the second circuit electrode 32 is formed. Also good.

  At least one of the first substrate 21 and the second substrate 31 may have a surface on the side facing the other of the first substrate 21 and the second substrate 31 formed of melamine resin, silicon nitride, or silicon dioxide. . For example, the entirety of the first substrate 21 and the second substrate 31 may be made of those materials, and an anchor layer or a protective film formed on the surfaces of the first substrate 21 and the second substrate 31 is provided. You may form with those materials. In this case, at least one of the first circuit member 20 and the second circuit member 30 has a region other than the portion where the first circuit electrode 22 and the second circuit electrode 32 are formed on the facing surfaces thereof. It will be composed of the material.

  Since melamine resin, silicon nitride, or silicon dioxide has low adhesion to conventional connection materials, circuit members provided on the surfaces facing each other tend to be difficult to bond sufficiently with the connection material. . On the other hand, the connection material of the preferred embodiment described above can form an adhesive layer having sufficient adhesive force with respect to melamine resin, silicon nitride, or silicon dioxide. Therefore, in the connection structure 1 according to the present embodiment, the first circuit member 20 and the second circuit member 30 have the first circuit member 20 and the second circuit member 30 on the surface thereof having an anchor layer or a protective film made of these materials. Even if it has 31, the 1st circuit member 20 and the 2nd circuit member 30 can be pasted up strongly.

  For example, the first circuit electrode 22 and the second circuit electrode 32 function as connection terminals for electrically connecting the first circuit member 20 and the second circuit member 30. Usually, the circuit member is provided with a large number of connection terminals. However, in this embodiment, the connection terminals (the first circuit electrode 22 and the second circuit electrode 32) may be singular in some cases. Good.

  The first circuit electrode 22 and the second circuit electrode 32 are made of metal, for example. In order to obtain a better electrical connection, at least one of the first circuit electrode 22 and the second circuit electrode 32 is made of at least one metal whose surface is selected from the group consisting of gold, silver, tin and platinum. It is preferable to be formed. Such a surface layer may be selected from gold, silver, platinum group, and tin, or may be applied in combination. Further, the first circuit electrode 22 and the second circuit electrode 32 may have a multilayer structure in which a plurality of metals are combined such as copper / nickel / gold. The first circuit electrode 22 and the second circuit electrode 32 may be made of a material having conductivity other than a metal such as ITO (indium tin oxide).

  Examples of the first circuit electrode 22 and the second circuit electrode 32 include an Ag paste electrode, a copper electrode, and an ITO electrode. Here, the Ag paste electrode means an electrode formed by applying Ag flakes dispersed in a thermosetting resin on an organic film by screen printing or the like, and then performing thermosetting. The copper electrode is an electrode mainly composed of copper, and may contain other components. Since the connection structure 1 of the present embodiment includes the adhesive layer 10 made of the connection material of the above-described preferred embodiment, the first circuit electrode 22 and the second circuit electrode 32 are these electrodes. Even if it exists, the high adhesiveness of the 1st circuit member 20 and the 2nd circuit member 30 can be acquired.

  Examples of the first circuit member 20 and the second circuit member 30 as described above include the following. In other words, a liquid crystal display panel having a glass substrate or a plastic substrate as a substrate and having a connection terminal formed of ITO or the like, a flexible printed wiring board (FPC) having a polyimide film as a substrate, a tape curing package (TCP), a chip-on Examples thereof include a film (COF) and a semiconductor silicon chip having a semiconductor substrate as a circuit substrate. As the first circuit member 20 and the second circuit member 30, the connection structure 1 is configured by appropriately combining these various circuit members as necessary.

  In the connection structure 1 of the present embodiment, the first circuit member 20 and the second circuit member 30 are disposed so as to face each other so that the first circuit electrode 22 and the second circuit electrode 32 face each other. It can be manufactured by placing a connecting material between the two and pressing in that direction in the stacking direction. During pressurization, heating may be further performed as necessary.

  Such a method can be performed more easily by using a film-like connecting material. That is, the connection structure 1 can be obtained by stacking the first circuit member 20, the film-like connection material, and the second circuit member 30 in this order, and performing pressurization and heating in this state. . Also in this case, the first circuit member 20 and the second circuit member 30 may be stacked so as to face each other in the same manner as described above.

  The pressure in the pressurization is not particularly limited as long as it does not damage the first circuit member 20 and the second circuit member 30. For example, the pressure is preferably 0.1 to 10 MPa. When heating, the temperature is not particularly limited, but is preferably 100 to 200 ° C. These pressurization and heating as required are preferably performed in the range of 0.5 to 100 seconds. In particular, in the formation of the laminated structure 1 of the present embodiment, since the connection material of the above-described preferred embodiment is used, it is sufficiently bonded even at a low temperature and in a short time compared to the case of using the conventional connection material. Can do. For example, sufficient adhesion can be achieved by heating at 130 to 180 ° C., 3 MPa, and 10 seconds.

  The first circuit member 20 and the second circuit member 30 are bonded by pressurization or heating in order to eliminate the possibility that volatile components are generated by heating at the time of connection, thereby reducing their connectivity. Before performing, it is preferable to heat-process previously.

  As described above, the connection material according to a preferred embodiment of the present invention is for bonding two circuit members having circuit electrodes on the surface so that the respective circuit electrodes are electrically connected to each other. It can be used as a so-called circuit connection material. More specifically, the connection material includes a first circuit member having a first circuit electrode formed on the first substrate and the first substrate, a second circuit board, and the second substrate. A second circuit electrode formed between the second circuit member and the second circuit member disposed with respect to the first circuit member so that the second circuit electrode faces the first circuit electrode. And can be used for bonding the first circuit member and the second circuit member.

  Moreover, the connection material of suitable embodiment can be applied to uses other than the circuit connection material mentioned above, for example, can be used suitably also for the connection of a photovoltaic cell. In a solar cell module, generally, a plurality of solar cells having surface electrodes are connected in series and / or in parallel. When connecting solar cells, the electrodes of the solar cells may be directly connected to each other. For example, the connection material of the present embodiment is applied to both surfaces of a metal foil such as a copper foil, and then used. Moreover, it can also be set as the aspect which connects the electrodes of a several photovoltaic cell in series and / or in parallel.

  EXAMPLES Hereinafter, although an Example demonstrates this invention still in detail, this invention is not necessarily limited to a following example.

[Preparation of connecting material]
Example 1
As a radical polymerizable substance, a 70 wt% solution of urethane acrylate oligomer (UA5500T, manufactured by Shin-Nakamura Chemical Co., Ltd.) in a toluene content of 25 parts by weight in terms of nonvolatile content, isocyanuric acid EO modified diacrylate (manufactured by Toagosei Co., Ltd., M-215) 10 parts by weight, 3 parts by weight of dicyclopentadiene type diacrylate (DCP-A, manufactured by Toagosei Co., Ltd.), and 3 parts by weight of 2-methacryloyloxyethyl acid phosphate (P-2M, manufactured by Kyoeisha Chemical) as a lactone compound 7 parts by weight of γ-butyrolactone acrylate represented by the above formula (1-1), as a curing agent that generates free radicals, 10 parts by weight of dilauroyl peroxide (Perroyl L, manufactured by NOF), as a thermoplastic resin, Nonvolatile conversion of polyester urethane resin (UR-8200, manufactured by Toyobo, 30% solution) 40 parts by weight, and 20 wt% solution obtained by dissolving ethylene-vinyl acetate copolymer (EV40W, manufactured by Mitsui DuPont Polychemical) in toluene, 10 parts by weight in terms of non-volatile content, polystyrene as conductive particles A nickel layer having a thickness of 0.2 μm is provided on the surface of the particles having the core as a core, and further 5 parts by weight of particles having an average particle diameter of 10 μm in which a gold layer having a thickness of 0.04 μm is provided outside the nickel layer A mixed solution was obtained.

  This mixed solution was applied onto a PET film with an applicator and then dried with hot air at 70 ° C. for 10 minutes to form a film-like connecting material having a thickness of 20 μm on the PET film. In this connection material, the weight part of the lactone compound was 15.2 parts by weight with respect to 100 parts by weight of the radical polymerizable substance (here, the total of UA5500, DCP-A, M-215 and P-2M).

(Example 2)
A film-like connecting material was formed in the same manner as in Example 1 except that the lactone compound was replaced with γ-butyrolactone methacrylate represented by the above formula (1-2). In this connection material, the weight part of the lactone compound was 15.2 parts by weight with respect to 100 parts by weight of the radical polymerizable substance (here, the total of UA5500, DCP-A, M-215 and P-2M).

Example 3
A film-like connecting material was obtained in the same manner as in Example 1 except that the lactone compound was replaced with the δ-valerolactone acrylate represented by the above formula (1-7). In this connection material, the weight part of the lactone compound was 15.2 parts by weight with respect to 100 parts by weight of the radical polymerizable substance (here, the total of UA5500, DCP-A, M-215 and P-2M).

Example 4
A film-like connecting material was obtained in the same manner as in Example 1 except that the lactone compound was replaced with δ-valerolactone methacrylate represented by the above formula (1-8). In this connection material, the weight part of the lactone compound was 15.2 parts by weight with respect to 100 parts by weight of the radical polymerizable substance (here, the total of UA5500, DCP-A, M-215 and P-2M).

(Example 5)
A film-like connecting material was obtained in the same manner as in Example 1 except that the lactone compound was replaced with mevalonic lactone acrylate. In this connection material, the weight part of the lactone compound was 15.2 parts by weight with respect to 100 parts by weight of the radical polymerizable substance (here, the total of UA5500, DCP-A, M-215 and P-2M).

(Example 6)
Example 1 except that the amount of lactone compound γ-butyrolactone methacrylate was changed to 12 parts by weight, and dicyclopentadiene diacrylate (DCP-A, manufactured by Toagosei Co., Ltd.) was not contained. Similarly, a film-like connecting material was obtained. In this connection material, the weight part of the lactone compound was 29.2 parts by weight with respect to 100 parts by weight of the radical polymerizable substance (here, the total of UA5500, M-215 and P-2M).

(Comparative Example 1)
A film-like connecting material was obtained in the same manner as in Example 1 except that acryloylmorpholine (manufactured by Kojin Co., Ltd., ACMO) was used instead of the lactone compound.

(Comparative Example 2)
A film-like connecting material was obtained in the same manner as in Example 1 except that isobonyl acrylate (manufactured by Osaka Organic Chemical Co., Ltd., IBXA) was used instead of the lactone compound.

(Comparative Example 3)
A film-like connecting material was obtained in the same manner as in Example 1 except that tetrahydrofurfuryl acrylate (manufactured by Osaka Organic Chemical Co., V # 150) was used instead of the lactone compound.

(Comparative Example 4)
A film-like connecting material was obtained in the same manner as in Example 1 except that cyclohexyl acrylate (manufactured by Osaka Organic Chemical Co., V # 155) was used in place of the lactone compound.

(Comparative Example 5)
A film-like connecting material was obtained in the same manner as in Example 1 except that phenoxyethyl acrylate (manufactured by Osaka Organic Chemical Co., V # 192) was used instead of the lactone compound.

Table 1 shows the compositions of the connection materials obtained in Examples 1 to 6 and Comparative Examples 1 to 5, respectively.

[Production and evaluation of connection structure]
(Production Example A: Production of connection structure of FPC and organic film)
Using each of the film-like connection materials obtained in Examples 1 to 6 and Comparative Examples 1 to 5, various connection structures were produced by the following methods. That is, a flexible circuit board (FPC-TEG) in which a copper circuit having a line width of 250 μm, a pitch of 500 μm, and a thickness of 18 μm is directly formed on a 75 μm-thick polyimide (copper surface is plated with 0.1 μm of tin) ) And an organic film on which a hard coat layer is provided on the surface of the polycarbonate and a melamine resin is further formed as an anchor layer thereon, a film-like connecting material is disposed between 130 ° C. and 2 MPa-10 seconds, The connection structure was obtained by connecting the FPC-TEG and the organic film via the connection material by heating and pressing under the condition that the width of the connection material was 2.0 mm. Specifically, after pasting a film-like connection material formed on a PET film on an anchor layer in an organic film and performing a temporary connection by applying heat and pressure at 70 ° C., 1 MPa for 2 seconds Then, the PET film was peeled, and the copper circuit side surface of FPC-TEG was attached to the PET film, and the above heating and pressurization was performed.

(Production Example B: Production of connection structure of FPC and silicon nitride glass substrate)
It replaced with the organic film, and except having used the silicon nitride glass substrate, it carried out similarly to manufacture example A, and used various connection materials of the film form obtained in Examples 1-6 and Comparative Examples 1-5, respectively. A connection structure was obtained.

(Measurement of adhesive strength)
For the various connection structures produced in Production Example A and Production Example B, the adhesive force when peeling the FPC-TEG from the connection structure in the 90 ° direction was measured at a peeling speed of 50 mm / min. Of the connection structures, those having an adhesive strength value of 6 N / cm or more were judged to have good adhesion. The obtained results are shown in Table 2.

[Production and evaluation of connection structure]
(Production Example C: Production of connection structure of FPC and silver paste film substrate)
Using each of the film-like connection materials obtained in Examples 1 to 6 and Comparative Examples 1 to 5, various connection structures were produced by the following methods. That is, a flexible circuit board (FPC-TEG) in which a copper circuit having a line width of 250 μm, a pitch of 500 μm, and a thickness of 18 μm is directly formed on a 75 μm-thick polyimide (copper surface is plated with 0.1 μm of tin) ) And a silver paste film substrate on which a silver paste electrode having a thickness of 8 to 10 μm is formed on the surface of polyethylene terephthalate, a film-like connecting material is disposed, and 130 ° C.−2 MPa−10 seconds, width 2 By applying heat and pressure under the condition of 0.0 mm, the FPC-TEG and the silver paste film substrate were connected via a connecting material to obtain a connection structure. Specifically, a film-like connection material formed on a PET film is pasted on a silver paste electrode of a silver paste film substrate, and is temporarily connected by heating and pressing under conditions of 70 ° C., 1 MPa, and 2 seconds. Thereafter, the PET film was peeled off, and the surface of the FPC-TEG on the copper circuit side was attached thereto, and the above heating and pressurization was performed.

(Measurement of connection resistance)
In the various connection structures obtained in Production Example C above, the resistance value between adjacent circuits between the FPC-TEG and the silver paste film substrate was initially treated for 250 hours at 85 ° C./85% RH. Both time points were measured using a multimeter. This resistance value was measured at 37 resistance values between adjacent circuits, and an average value and a maximum value thereof were obtained. Of the connection structures, those having a change rate of the average value of resistance values within 2 times were judged to have good connection reliability. The obtained results are shown in Table 2.

  As shown in Table 2, the connection structure manufactured using the film-like connection materials of Examples 1 to 6 has good adhesiveness regardless of whether the adhesive surface is composed of a melamine resin film or silicon nitride glass. It was confirmed that it had good connection reliability. On the other hand, the connection structures manufactured using the film-like connection materials of Comparative Examples 1 to 5 did not obtain good adhesion even when the connection surface was either a melamine resin film or silicon nitride glass. .

  DESCRIPTION OF SYMBOLS 1 ... Connection structure, 7 ... Electroconductive particle, 10 ... Adhesive layer, 11 ... Adhesive, 20 ... 1st circuit member, 21 ... 1st board | substrate, 22 ... 1st circuit electrode (1st connection terminal ), 30... Second circuit member, 31... Second substrate, 32... Second circuit electrode (second connection terminal).

Claims (10)

Contains a radical polymerizable substance, a lactone compound and a curing agent that generates free radicals,
A connection material comprising 7 to 40 parts by weight of the lactone compound with respect to 100 parts by weight of the radical polymerizable substance.   The connection material according to claim 1, wherein the lactone compound is a lactone (meth) acrylate. A first circuit member having a first substrate and a first circuit electrode formed on the first substrate;
A second circuit electrode formed on the second substrate and facing the first circuit member so that the second circuit electrode faces the first circuit electrode; A second circuit member arranged
An adhesive layer disposed between the first circuit member and the second circuit member and bonding the first circuit member and the second circuit member;
A connection structure in which the adhesive layer is formed from the connection material according to claim 1.   4. The connection structure according to claim 3, wherein at least one of the first substrate and the second substrate is formed of a melamine resin at least on a surface facing the other of the first substrate and the second substrate. .   4. The connection structure according to claim 3, wherein at least one of the first substrate and the second substrate is formed of silicon nitride at least on a surface facing the other of the first substrate and the second substrate. .   The connection structure according to claim 3, wherein at least one of the first substrate and the second substrate is made of silicon dioxide at least on a surface facing the other of the first substrate and the second substrate. .   The connection structure according to any one of claims 3 to 6, wherein at least one of the first circuit electrode and the second circuit electrode is an Ag paste electrode.   The connection structure according to any one of claims 3 to 6, wherein at least one of the first circuit electrode and the second circuit electrode is a copper electrode.   The connection structure according to any one of claims 3 to 6, wherein at least one of the first circuit electrode and the second circuit electrode is an ITO electrode.   A first circuit member having a first substrate and a first circuit electrode formed on the first substrate; a second circuit electrode formed on the second substrate; and a second circuit electrode formed on the second substrate. And a second circuit member disposed opposite to the first circuit member so that the second circuit electrode faces the first circuit electrode. A method for manufacturing a connection structure, comprising the steps of: arranging and pressurizing the connection material, and bonding the first circuit member and the second circuit member.

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