JP2018006084A - Conductive material, connection structure and method for producing connection structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a conductive material that allows solder to be efficiently disposed between connected electrodes due to excellent solder cohesiveness, and can improve the conduction reliability and insulation reliability.SOLUTION: A conductive material contains, on the external surface of a conductive part, a plurality of conductive particles having solder, a thermosetting component, a flux, and a water absorbent.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a conductive material including conductive particles having solder. The present invention also relates to a connection structure using the conductive material and a method for manufacturing the connection structure.

  Anisotropic conductive materials such as anisotropic conductive pastes and anisotropic conductive films are widely known. In the anisotropic conductive material, conductive particles are dispersed in a binder resin.

  In order to obtain various connection structures, the anisotropic conductive material is, for example, a connection between a flexible printed circuit board and a glass substrate (FOG (Film on Glass)) or a connection between a semiconductor chip and a flexible printed circuit board (COF ( Chip on Film)), connection between a semiconductor chip and a glass substrate (COG (Chip on Glass)), connection between a flexible printed circuit board and a glass epoxy substrate (FOB (Film on Board)), and the like.

  For example, when electrically connecting the electrode of the flexible printed circuit board and the electrode of the glass epoxy substrate by the anisotropic conductive material, an anisotropic conductive material containing conductive particles is disposed on the glass epoxy substrate. To do. Next, a flexible printed circuit board is laminated, and heated and pressurized. As a result, the anisotropic conductive material is cured, and the electrodes are electrically connected via the conductive particles to obtain a connection structure.

  As an example of the anisotropic conductive material, Patent Document 1 described below describes an anisotropic conductive material including conductive particles and a resin component that cannot be cured at the melting point of the conductive particles. Specifically, the conductive particles include tin (Sn), indium (In), bismuth (Bi), silver (Ag), copper (Cu), zinc (Zn), lead (Pb), cadmium (Cd ), Metals such as gallium (Ga) and thallium (Tl), and alloys of these metals.

  In Patent Document 1, a resin heating step for heating the anisotropic conductive resin to a temperature higher than the melting point of the conductive particles and at which the curing of the resin component is not completed, and a resin component curing step for curing the resin component The electrical connection between the electrodes is described. Patent Document 1 describes that mounting is performed with the temperature profile shown in FIG. In Patent Document 1, the conductive particles melt in a resin component that is not completely cured at a temperature at which the anisotropic conductive resin is heated.

  Patent Document 2 below discloses a thermosetting resin composition containing solder particles having a melting point of 240 ° C. or lower, a thermosetting resin binder, and a flux component. The thermosetting resin binder contains an epoxy resin and a curing agent. In the epoxy resin, the aromatic hydrocarbon group (a1) having a bonding site with another group in the aromatic nucleus and the hydrocarbon group (a2) or other hydrocarbon group (a3) containing an ether bond are acetal. A linear bifunctional epoxy resin (A) having a structure bonded via a bond (a4) and having a structure in which a glycidyloxy group is bonded to an aromatic hydrocarbon group (a1), and a weight average molecular weight ( Mw) containing at least one flexible epoxy resin selected from 15000 to 70000 linear bifunctional phenoxy resin (B). The curing agent contains a flexible acid anhydride curing agent composed of an aliphatic acid anhydride having an acid anhydride equivalent of 200 to 400.

  In Patent Document 2, the amount of the curing agent used is appropriately set, but the stoichiometric equivalent ratio of the curing agent to the epoxy equivalent of the epoxy resin may be in the range of 0.8 to 1.2. As described to be preferable, the acid anhydride described in Patent Document 2 is used as a curing agent for an epoxy resin and is not used as a water-absorbing agent.

JP 2004-260131 A JP2013-216830A

  In the conventional conductive materials described in Patent Documents 1 and 2, there are cases where the conductive material cannot be efficiently disposed between the electrodes to be connected. In particular, when the conductive material is thinly applied by screen coating or the like, the solder in the conductive particles may hardly aggregate on the electrode, and as a result, the conduction reliability and the insulation reliability may be lowered.

  An object of the present invention is to provide a conductive material that can efficiently arrange solder between electrodes to be connected due to excellent solder cohesion and can improve conduction reliability and insulation reliability. . Another object of the present invention is to provide a connection structure using the conductive material and a method for manufacturing the connection structure.

  According to a wide aspect of the present invention, there is provided a conductive material including a plurality of conductive particles having solder, a thermosetting component, a flux, and a water absorbing agent on an outer surface portion of a conductive portion.

  On the specific situation with the electrically-conductive material which concerns on this invention, content of the said water absorbing agent is 0.1 to 5 weight% in 100 weight% of said electrically-conductive materials.

  On the specific situation with the electrically-conductive material which concerns on this invention, the water absorption amount of the said water absorbing agent in 70 degreeC is 0.03 ml / g or more.

  On the specific situation with the electrically-conductive material which concerns on this invention, the said electrically-conductive material contains a propylene compound, an acetylene compound, or an acid anhydride as the said water absorbing agent.

  On the specific situation with the electrically-conductive material which concerns on this invention, the said electrically-conductive material contains an acid anhydride as the said water absorbing agent.

  On the specific situation with the electrically-conductive material which concerns on this invention, the said acid anhydride is a liquid at the melting temperature of -10 degreeC of a flux.

  On the specific situation with the electrically-conductive material which concerns on this invention, the said thermosetting component contains a thermosetting compound and a hardening | curing agent.

  In a specific aspect of the conductive material according to the present invention, the curing agent is a thiol curing agent.

  In a specific aspect of the conductive material according to the present invention, the conductive material is a conductive paste.

  According to a wide aspect of the present invention, a first connection target member having at least one first electrode on the surface, a second connection target member having at least one second electrode on the surface, and the first A connection portion connecting the second connection target member and the second connection target member, wherein the material of the connection portion is the conductive material described above, and the first electrode and the second electrode Is provided that is electrically connected by a solder part in the connection part.

  In a specific aspect of the connection structure according to the present invention, the first electrode and the second electrode face each other in the stacking direction of the first electrode, the connection portion, and the second electrode. When the portion is viewed, the solder portion in the connection portion is arranged in 50% or more of the area of 100% of the portion where the first electrode and the second electrode face each other.

  According to a wide aspect of the present invention, using the conductive material described above, the step of disposing the conductive material on the surface of the first connection target member having at least one first electrode on the surface; On the surface opposite to the first connection target member side of the material, the second connection target member having at least one second electrode on the surface, the first electrode and the second electrode are The step of disposing so as to face each other, and heating the conductive material above the melting point of the solder in the conductive particles and above the curing temperature of the thermosetting component, the first connection object member and the second A step of forming a connection portion connecting a member to be connected with the conductive material, and electrically connecting the first electrode and the second electrode with a solder portion in the connection portion. Provided with a method for manufacturing a connection structure It is.

  In a specific aspect of the manufacturing method of the connection structure according to the present invention, the first electrode and the second electrode are stacked in the stacking direction of the first electrode, the connection portion, and the second electrode. A connection in which the solder part in the connection part is arranged in 50% or more of the area of 100% of the part where the first electrode and the second electrode face each other when the part facing each other is viewed. Get a structure.

  The conductive material according to the present invention includes a plurality of conductive particles having solder, a thermosetting component, a flux, and a water-absorbing agent on the outer surface portion of the conductive portion. Solder can be efficiently arranged between the electrodes to be connected, and conduction reliability and insulation reliability can be improved.

FIG. 1 is a cross-sectional view schematically showing a connection structure obtained using a conductive material according to an embodiment of the present invention. 2A to 2C are cross-sectional views for explaining each step of an example of a method for manufacturing a connection structure using a conductive material according to an embodiment of the present invention. FIG. 3 is a cross-sectional view showing a modification of the connection structure. FIG. 4 is a cross-sectional view showing a first example of conductive particles that can be used as a conductive material. FIG. 5 is a cross-sectional view showing a second example of conductive particles that can be used for the conductive material. FIG. 6 is a cross-sectional view showing a third example of conductive particles that can be used for the conductive material.

  Details of the present invention will be described below.

(Conductive material)
The conductive material according to the present invention includes a plurality of conductive particles, a thermosetting component, a flux, and a water absorbing agent.

  The conductive particles have a conductive part. The conductive particles have solder on the outer surface portion of the conductive portion. Solder is contained in the conductive part and is a part or all of the conductive part.

  In the present invention, since the above configuration is provided, the solder can be efficiently arranged between the electrodes to be connected due to the excellent solder cohesiveness, and the conduction reliability and the insulation reliability can be improved. . When the electrode width or the inter-electrode width is narrow, there is a tendency that the solder is difficult to gather on the electrodes, but in the present invention, the solder is sufficiently gathered on the electrodes even if the electrode width or the inter-electrode width is narrow. Can do. In the present invention, when the electrodes are electrically connected, the solder tends to gather between the upper and lower electrodes, and the solder can be efficiently disposed on the electrodes (lines). Also, in the present invention, when an electrode has a wide electrode width, the solder is more efficiently arranged on the electrode.

  The above-described effect is manifested because water present in the conductive material or water generated during heating can be removed by the water absorbing agent. If water is present in the conductive material, the flux dissolves in the water, and the oxide film on the electrode surface or the solder surface cannot be sufficiently removed, and the wettability of the solder also deteriorates. In the present invention, by removing water with the water-absorbing agent, the solder can be efficiently arranged between the electrodes to be connected, and the conduction reliability and the insulation reliability can be improved.

  Further, in the present invention, a part of the solder is difficult to be disposed in a region (space) where no electrode is formed, and the amount of solder disposed in a region where no electrode is formed can be considerably reduced. In the present invention, the solder that is not located between the opposing electrodes can be efficiently moved between the opposing electrodes. Therefore, the conduction reliability between the electrodes can be improved. In addition, it is possible to prevent electrical connection between the laterally adjacent electrodes that should not be connected, and to improve the insulation reliability.

  Furthermore, in the present invention, it is possible to prevent displacement between the electrodes. In the present invention, when the second connection target member is superimposed on the first connection target member having the conductive material disposed on the upper surface, the electrode of the first connection target member and the electrode of the second connection target member Even when the first connection target member and the second connection target member are overlapped in a state where the alignment of the first connection target member and the second connection target member are overlaid, the shift is corrected and the electrode of the first connection target member and the second connection target are corrected. The electrode of the member can be connected (self-alignment effect).

  In order to arrange the solder more efficiently on the electrode, the viscosity (η25) of the conductive material at 25 ° C. is preferably 30 Pa · s or more, more preferably 80 Pa · s or more, preferably 400 Pa · s. Hereinafter, more preferably 200 Pa · s or less. The said viscosity ((eta) 25) can be suitably adjusted with the kind and compounding quantity of a compounding component.

  The viscosity (η25) can be measured using, for example, an E-type viscometer (“TVE22L” manufactured by Toki Sangyo Co., Ltd.) and the like at 25 ° C. and 5 rpm.

  In order to arrange the solder more efficiently on the electrode, the viscosity (η-10) of the conductive material at the melting point of the solder in the conductive particles −10 ° C. is preferably 0.1 Pa · s or more, more preferably 1 Pa. · S or more, more preferably 3 Pa · s or more, preferably 20 Pa · s or less, more preferably 15 Pa · s or less, still more preferably 10 Pa · s or less. The said viscosity ((eta) -10) can be suitably adjusted with the kind and compounding quantity of a compounding component.

  The melting point of the solder of −10 ° C. is a temperature that easily affects the movement of the conductive particles onto the electrode.

  The viscosity (η-10) is, for example, using STRESSTECH (manufactured by EOLOGICA) or the like under the conditions of strain control 1 rad, frequency 1 Hz, heating rate 20 ° C./min, measurement temperature range 40 ° C. to solder melting point ° C. It can be measured. In this measurement, the viscosity of the solder at a melting point of −10 ° C. is read.

  The conductive material is used as a conductive paste and a conductive film. The conductive paste is preferably an anisotropic conductive paste, and the conductive film is preferably an anisotropic conductive film. From the viewpoint of further disposing the solder on the electrode, the conductive material is preferably a conductive paste.

  The method for producing the conductive paste is not particularly limited, and examples thereof include a method of mixing using a mixer such as a homodisper, a homomixer, a universal mixer, a planetary mixer, a kneader, or a three roll.

  The conductive material is preferably used for electrical connection of electrodes. The conductive material is preferably a circuit connection material.

  Hereinafter, each component contained in the conductive material will be described.

(Conductive particles)
The electroconductive particle which concerns on this invention has a solder in the outer surface part of an electroconductive part. The conductive particles may be solder particles formed by solder. The solder particles have solder on the outer surface portion of the conductive portion. The solder particles are particles in which both the central portion and the outer surface of the conductive portion are solder. The solder particles do not have base particles as core particles. The solder particles are different from conductive particles including base particles and conductive portions arranged on the surface of the base particles. The solder particles include, for example, solder preferably at 80% by weight or more, more preferably 90% by weight or more, and further preferably 95% by weight or more.

  The said electroconductive particle may have a base material particle and the electroconductive part arrange | positioned on the surface of this base material particle. In this case, the conductive particles have solder on the outer surface portion of the conductive portion. As compared with the case where the solder particles are used as the conductive particles, the case where the conductive particles including the base particles not formed by the solder and the solder portion arranged on the surface of the base particles are used. The conductive particles are less likely to collect on the electrodes, and the conductive particles that have moved onto the electrodes tend to move out of the electrodes because of the low solderability between the conductive particles. There is a tendency that the effect of suppressing misalignment also becomes low. Therefore, the conductive particles are preferably solder particles formed by solder.

  From the viewpoint of effectively reducing the connection resistance in the connection structure and effectively suppressing the generation of voids, a carboxyl group or an amino group is present on the outer surface of the conductive particles (the outer surface of the solder). It is preferable that a carboxyl group is present, and an amino group is preferably present. A group containing a carboxyl group or an amino group is shared on the outer surface of the conductive particle (the outer surface of the solder) via a Si-O bond, an ether bond, an ester bond, or a group represented by the following formula (X). Bonding is preferred. The group containing a carboxyl group or an amino group may contain both a carboxyl group and an amino group. In the following formula (X), the right end and the left end represent a binding site.

  Hydroxyl groups exist on the surface of the solder. By covalently bonding this hydroxyl group and a group containing a carboxyl group, a stronger bond can be formed than in the case of bonding by other coordination bond (chelate coordination) or the like, so the connection resistance between the electrodes is reduced, And the electroconductive particle which can suppress generation | occurrence | production of a void is obtained.

  In the conductive particles, the bond form between the surface of the solder and the group containing a carboxyl group may not include a coordination bond, and may not include a bond due to a chelate coordination.

  From the viewpoint of effectively reducing the connection resistance in the connection structure and effectively suppressing the generation of voids, the conductive particle is a compound having a functional group capable of reacting with a hydroxyl group and a carboxyl group or an amino group ( Hereinafter, it is preferably obtained by reacting a hydroxyl group on the surface of the solder with a functional group capable of reacting with the hydroxyl group using a compound X). In the above reaction, a covalent bond is formed. By reacting a hydroxyl group on the surface of the solder with a functional group capable of reacting with the hydroxyl group in the compound X, conductive particles in which a group containing a carboxyl group or an amino group is covalently bonded to the surface of the solder are easily obtained. It is also possible to obtain conductive particles in which a group containing a carboxyl group or an amino group is covalently bonded to the surface of the solder via an ether bond or an ester bond. By reacting a hydroxyl group on the surface of the solder with a functional group capable of reacting with the hydroxyl group, the compound X can be chemically bonded to the surface of the solder in the form of a covalent bond.

  Examples of the functional group capable of reacting with the hydroxyl group include a hydroxyl group, a carboxyl group, an ester group, and a carbonyl group. A hydroxyl group or a carboxyl group is preferred. The functional group capable of reacting with the hydroxyl group may be a hydroxyl group or a carboxyl group.

  Examples of the compound having a functional group capable of reacting with a hydroxyl group include levulinic acid, glutaric acid, glycolic acid, succinic acid, malic acid, oxalic acid, malonic acid, adipic acid, 5-ketohexanoic acid, 3-hydroxypropionic acid, 4- Aminobutyric acid, 3-mercaptopropionic acid, 3-mercaptoisobutyric acid, 3-methylthiopropionic acid, 3-phenylpropionic acid, 3-phenylisobutyric acid, 4-phenylbutyric acid, decanoic acid, dodecanoic acid, tetradecanoic acid, pentadecanoic acid, Hexadecanoic acid, 9-hexadecenoic acid, heptadecanoic acid, stearic acid, oleic acid, vaccenic acid, linoleic acid, (9,12,15) -linolenic acid, nonadecanoic acid, arachidic acid, decanedioic acid and dodecanedioic acid It is done. Glutaric acid or glycolic acid is preferred. Only 1 type may be used for the compound which has the functional group which can react with the said hydroxyl group, and 2 or more types may be used together. The compound having a functional group capable of reacting with the hydroxyl group is preferably a compound having at least one carboxyl group.

  The compound X preferably has a flux action, and the compound X preferably has a flux action in a state of being bonded to the solder surface. The compound having a flux action can remove the oxide film on the surface of the solder and the oxide film on the surface of the electrode. The carboxyl group has a flux action.

  Examples of the compound having a flux action include levulinic acid, glutaric acid, glycolic acid, succinic acid, 5-ketohexanoic acid, 3-hydroxypropionic acid, 4-aminobutyric acid, 3-mercaptopropionic acid, 3-mercaptoisobutyric acid, 3- Examples include methylthiopropionic acid, 3-phenylpropionic acid, 3-phenylisobutyric acid, and 4-phenylbutyric acid. Glutaric acid or glycolic acid is preferred. As for the compound which has the said flux effect | action, only 1 type may be used and 2 or more types may be used together.

  From the viewpoint of effectively reducing the connection resistance in the connection structure and effectively suppressing the generation of voids, the functional group capable of reacting with the hydroxyl group in the compound X is preferably a hydroxyl group or a carboxyl group. The functional group capable of reacting with the hydroxyl group in the compound X may be a hydroxyl group or a carboxyl group. When the functional group capable of reacting with the hydroxyl group is a carboxyl group, the compound X preferably has at least two carboxyl groups. By reacting a part of the carboxyl group of the compound having at least two carboxyl groups with the hydroxyl group on the surface of the solder, conductive particles in which the group containing the carboxyl group is covalently bonded to the surface of the solder can be obtained.

  The manufacturing method of the said electroconductive particle is equipped with the process of mixing the compound, catalyst, and solvent which have the functional group and carboxyl group which can react with this electroconductive particle and a hydroxyl group, for example using electroconductive particle. In the method for producing conductive particles, conductive particles in which a group containing a carboxyl group is covalently bonded to the surface of the solder can be easily obtained by the mixing step.

  Moreover, in the said manufacturing method of electroconductive particle, using electroconductive particle, this electroconductive particle, the compound which has the functional group and carboxyl group which can react with the said hydroxyl group, the said catalyst, and the said solvent are mixed, and it heats. It is preferable. By the mixing and heating step, conductive particles in which a group containing a carboxyl group is covalently bonded to the surface of the solder can be obtained more easily.

  Examples of the solvent include alcohol solvents such as methanol, ethanol, propanol and butanol, acetone, methyl ethyl ketone, ethyl acetate, toluene and xylene. The solvent is preferably an organic solvent, and more preferably toluene. As for the said solvent, only 1 type may be used and 2 or more types may be used together.

  Examples of the catalyst include p-toluenesulfonic acid, benzenesulfonic acid and 10-camphorsulfonic acid. The catalyst is preferably p-toluenesulfonic acid. As for the said catalyst, only 1 type may be used and 2 or more types may be used together.

  It is preferable to heat at the time of the mixing. The heating temperature is preferably 90 ° C or higher, more preferably 100 ° C or higher, preferably 130 ° C or lower, more preferably 110 ° C or lower.

  From the viewpoint of effectively reducing the connection resistance in the connection structure and effectively suppressing the generation of voids, the conductive particles react with the isocyanate compound to the hydroxyl group on the surface of the solder using the isocyanate compound. It is preferable that it is obtained through the process of making it. In the above reaction, a covalent bond is formed. By reacting the hydroxyl group on the surface of the solder with the isocyanate compound, it is possible to easily obtain conductive particles in which the nitrogen atom of the group derived from the isocyanate group is covalently bonded to the surface of the solder. By reacting the isocyanate compound with a hydroxyl group on the surface of the solder, a group derived from an isocyanate group can be chemically bonded to the surface of the solder in the form of a covalent bond.

  Examples of the isocyanate compound include diphenylmethane-4,4'-diisocyanate (MDI), hexamethylene diisocyanate (HDI), toluene diisocyanate (TDI), and isophorone diisocyanate (IPDI). Isocyanate compounds other than these may be used. After reacting this compound on the surface of the solder, by reacting the residual isocyanate group and a compound having reactivity with the residual isocyanate group and having a carboxyl group, the surface of the solder is represented by the above formula (X). A carboxyl group can be introduced through the group to be formed.

  Moreover, as said isocyanate compound, you may use the compound which has an unsaturated double bond and has an isocyanate group. Examples include 2-acryloyloxyethyl isocyanate and 2-isocyanatoethyl methacrylate. After reacting the isocyanate group of this compound on the surface of the solder, the surface of the solder is reacted with a compound having a functional group having reactivity with the remaining unsaturated double bond and having a carboxyl group. A carboxyl group can be introduced into the group via the group represented by the above formula (X).

  Moreover, as said isocyanate compound, you may use the silane coupling agent which has an isocyanate group. After reacting the isocyanate group of the silane coupling agent on the surface of the solder, the compound having reactivity with the remaining group and having a carboxyl group is reacted with the surface of the solder by the above formula (X). A carboxyl group can be introduced through the group to be formed.

  Examples of the silane coupling agent having an isocyanate group include 3-isocyanatepropyltriethoxysilane (“KBE-9007” manufactured by Shin-Etsu Silicone), 3-isocyanatepropyltrimethoxysilane (“Y-5187” manufactured by MOMENTIVE), and the like. Is mentioned. As for the said silane coupling agent, only 1 type may be used and 2 or more types may be used together.

  Moreover, an isocyanate group can be easily reacted with a silane coupling agent. Since the solder particles can be easily obtained, the carboxyl group is introduced by a reaction using a silane coupling agent having a carboxyl group or a reaction using a silane coupling agent having an isocyanate group. It is preferably introduced later by reacting a group derived from the silane coupling agent with a compound having at least one carboxyl group.

  The conductive particles are preferably obtained by reacting the isocyanate compound with a hydroxyl group on the surface of the solder using the isocyanate compound and then reacting a compound having at least one carboxyl group.

  From the viewpoint of further reducing the connection resistance in the connection structure and further suppressing the generation of voids, the compound having at least one carboxyl group preferably has a plurality of carboxyl groups.

  Examples of the compound having at least one carboxyl group include levulinic acid, glutaric acid, glycolic acid, succinic acid, malic acid, oxalic acid, malonic acid, adipic acid, 5-ketohexanoic acid, 3-hydroxypropionic acid, 4-amino Butyric acid, 3-mercaptopropionic acid, 3-mercaptoisobutyric acid, 3-methylthiopropionic acid, 3-phenylpropionic acid, 3-phenylisobutyric acid, 4-phenylbutyric acid, decanoic acid, dodecanoic acid, tetradecanoic acid, pentadecanoic acid, hexadecane Examples include acid, 9-hexadecenoic acid, heptadecanoic acid, stearic acid, oleic acid, vaccenic acid, linoleic acid, (9,12,15) -linolenic acid, nonadecanoic acid, arachidic acid, decanedioic acid, and dodecanedioic acid. . Glutaric acid, adipic acid or glycolic acid is preferred. As for the compound which has at least 1 said carboxyl group, only 1 type may be used and 2 or more types may be used together.

  After reacting the isocyanate compound with the hydroxyl group on the surface of the solder using the isocyanate compound, the carboxyl group of the compound having a plurality of carboxyl groups is reacted with the hydroxyl group on the surface of the solder. The group containing can be left.

  In the method for producing conductive particles, the conductive particles are used and the isocyanate compound is used to react the hydroxyl group on the surface of the solder with the isocyanate compound, and then the compound having at least one carboxyl group is reacted. Thus, conductive particles in which a group containing a carboxyl group is bonded to the surface of the solder via the group represented by the above formula (X) are obtained. In the method for producing conductive particles, conductive particles in which a group containing a carboxyl group is introduced on the surface of the solder can be easily obtained by the above-described steps.

  The following method is mentioned as a specific manufacturing method of the said electroconductive particle. Conductive particles are dispersed in an organic solvent, and a silane coupling agent having an isocyanate group is added. Thereafter, a silane coupling agent is covalently bonded to the solder surface using a reaction catalyst of hydroxyl groups and isocyanate groups on the solder surface of the conductive particles. Next, a hydroxyl group is generated by hydrolyzing the alkoxy group bonded to the silicon atom of the silane coupling agent. The produced hydroxyl group is reacted with a carboxyl group of a compound having at least one carboxyl group.

  Moreover, the following method is mentioned as a specific manufacturing method of the said electroconductive particle. Conductive particles are dispersed in an organic solvent, and a compound having an isocyanate group and an unsaturated double bond is added. Then, a covalent bond is formed using the reaction catalyst of the hydroxyl group and isocyanate group of the solder surface of electroconductive particle. Thereafter, the unsaturated double bond introduced is reacted with a compound having an unsaturated double bond and a carboxyl group.

  As a reaction catalyst for the hydroxyl group and isocyanate group on the solder surface of the conductive particles, a tin catalyst (dibutyltin dilaurate, etc.), an amine catalyst (triethylenediamine, etc.), a carboxylate catalyst (lead naphthenate, potassium acetate, etc.), And a trialkylphosphine catalyst (such as triethylphosphine).

  From the viewpoint of effectively reducing the connection resistance in the connection structure and effectively suppressing the generation of voids, the compound having at least one carboxyl group is a compound represented by the following formula (1): Is preferred. The compound represented by the following formula (1) has a flux action. Moreover, the compound represented by following formula (1) has a flux effect | action in the state introduced into the surface of solder.

  In said formula (1), X represents the functional group which can react with a hydroxyl group, R represents a C1-C5 bivalent organic group. The organic group may contain a carbon atom, a hydrogen atom, and an oxygen atom. The organic group may be a divalent hydrocarbon group having 1 to 5 carbon atoms. The main chain of the organic group is preferably a divalent hydrocarbon group. In the organic group, a carboxyl group or a hydroxyl group may be bonded to a divalent hydrocarbon group. Examples of the compound represented by the above formula (1) include citric acid.

  The compound having at least one carboxyl group is preferably a compound represented by the following formula (1A) or the following formula (1B). The compound having at least one carboxyl group is preferably a compound represented by the following formula (1A), and more preferably a compound represented by the following formula (1B).

  In said formula (1A), R represents a C1-C5 bivalent organic group. R in the above formula (1A) is the same as R in the above formula (1).

  In said formula (1B), R represents a C1-C5 bivalent organic group. R in the above formula (1B) is the same as R in the above formula (1).

  A group represented by the following formula (2A) or the following formula (2B) is preferably bonded to the surface of the solder. A group represented by the following formula (2A) is preferably bonded to the surface of the solder, and more preferably a group represented by the following formula (2B) is bonded. In the following formula (2A), the left end represents a binding site.

  In said formula (2A), R represents a C1-C5 bivalent organic group. R in the above formula (2A) is the same as R in the above formula (1). In the following formula (2B), the left end represents a binding site.

  In said formula (2B), R represents a C1-C5 bivalent organic group. R in the above formula (2B) is the same as R in the above formula (1).

  From the viewpoint of improving the wettability of the solder surface, the molecular weight of the compound having at least one carboxyl group is preferably 10,000 or less, more preferably 1000 or less, and even more preferably 500 or less.

  The molecular weight means a molecular weight that can be calculated from the structural formula when the compound having at least one carboxyl group is not a polymer and when the structural formula of the compound having at least one carboxyl group can be specified. Further, when the compound having at least one carboxyl group is a polymer, it means a weight average molecular weight.

  From the viewpoint of more efficiently arranging the solder on the electrode, the conductive particles preferably have a conductive particle main body and an anionic polymer arranged on the surface of the conductive particle main body. The conductive particles are preferably obtained by surface-treating the conductive particle body with an anionic polymer or a compound that becomes an anionic polymer. The conductive particles are preferably a surface treated product of an anionic polymer or a compound that becomes an anionic polymer. As for the said anion polymer and the compound used as the said anion polymer, only 1 type may respectively be used and 2 or more types may be used together. The anionic polymer is a polymer having an acidic group.

  As a method of surface-treating the conductive particle body with an anionic polymer, as an anionic polymer, for example, a (meth) acrylic polymer copolymerized with (meth) acrylic acid, synthesized from a dicarboxylic acid and a diol and having carboxyl groups at both ends are used. Polyester polymer having a carboxyl group at both ends obtained by intermolecular dehydration condensation reaction of dicarboxylic acid, polyester polymer synthesized from dicarboxylic acid and diamine and having carboxyl group at both ends, and modified poval having carboxyl group (Nippon Synthetic Chemical Co., Ltd. "GOHSEX T") etc., and the method of making the carboxyl group of an anionic polymer react with the hydroxyl group of the surface of an electroconductive particle main body is mentioned.

Examples of the anion portion of the anion polymer include the carboxyl group, and other than that, a tosyl group (p-H ₃ CC ₆ H ₄ S (═O) ₂ —), a sulfonate ion group (—SO ₃ ^— ), And phosphate ion groups (—PO ₄ ⁻ ) and the like.

  In addition, as another method of the surface treatment, a compound having a functional group that reacts with a hydroxyl group on the surface of the conductive particle main body and having a functional group that can be polymerized by addition or condensation reaction is used. The method of polymerizing on the surface of an electroconductive particle main body is mentioned. Examples of the functional group that reacts with the hydroxyl group on the surface of the conductive particle body include a carboxyl group and an isocyanate group, and the functional group that polymerizes by addition and condensation reactions includes a hydroxyl group, a carboxyl group, an amino group, and (meta ) An acryloyl group is mentioned.

  The weight average molecular weight of the anionic polymer is preferably 2000 or more, more preferably 3000 or more, preferably 10,000 or less, more preferably 8000 or less. When the weight average molecular weight is not less than the above lower limit and not more than the above upper limit, a sufficient amount of charge and flux properties can be introduced on the surface of the conductive particles. Thereby, the cohesiveness of electroconductive particle can be effectively improved at the time of conductive connection, and the oxide film on the surface of an electrode can be effectively removed at the time of connection of the connection object member.

  When the weight average molecular weight is not less than the above lower limit and not more than the above upper limit, it is easy to dispose an anionic polymer on the surface of the conductive particle main body, and effectively increase the cohesiveness of the conductive particles during conductive connection. And the conductive particles can be more efficiently arranged on the electrode.

  The weight average molecular weight indicates a weight average molecular weight in terms of polystyrene measured by gel permeation chromatography (GPC).

  The weight average molecular weight of the polymer obtained by surface-treating the conductive particle main body with a compound that becomes an anionic polymer is obtained by dissolving the solder in the conductive particles, and diluting the conductive particles with diluted hydrochloric acid that does not cause decomposition of the polymer After removal, it can be determined by measuring the weight average molecular weight of the remaining polymer.

  Regarding the introduction amount of the anionic polymer on the surface of the conductive particles, the acid value per 1 g of the conductive particles is preferably 1 mgKOH or more, more preferably 2 mgKOH or more, preferably 10 mgKOH or less, more preferably 6 mgKOH or less. When the acid value is not less than the above lower limit and not more than the above upper limit, the heat resistance of the cured product is further enhanced, and discoloration of the cured product is further suppressed.

  The acid value is measured as follows.

Method for measuring acid value:
1 g of conductive particles is added to 36 g of acetone and dispersed with an ultrasonic wave for 1 minute. Then, it can titrate with a 0.1 mol / L potassium hydroxide ethanol solution using phenolphthalein as an indicator.

  Next, specific examples of conductive particles will be described with reference to the drawings.

  FIG. 4 is a cross-sectional view showing a first example of conductive particles that can be used as a conductive material.

  The conductive particles 21 shown in FIG. 4 are solder particles. The conductive particles 21 are entirely formed of solder. The conductive particles 21 do not have base particles in the core, and are not core-shell particles. As for the electroconductive particle 21, both the center part and the outer surface part of an electroconductive part are formed with the solder.

  FIG. 5 is a cross-sectional view showing a second example of conductive particles that can be used for the conductive material.

  The conductive particle 31 shown in FIG. 5 includes a base particle 32 and a conductive part 33 disposed on the surface of the base particle 32. The conductive portion 33 covers the surface of the base particle 32. The conductive particles 31 are coated particles in which the surface of the base particle 32 is covered with the conductive portion 33.

  The conductive portion 33 includes a second conductive portion 33A and a solder portion 33B (first conductive portion). The conductive particle 31 includes a second conductive portion 33A between the base particle 32 and the solder portion 33B. Therefore, the conductive particles 31 are composed of the base particle 32, the second conductive portion 33A disposed on the surface of the base particle 32, and the solder portion 33B disposed on the outer surface of the second conductive portion 33A. With.

  FIG. 6 is a cross-sectional view showing a third example of conductive particles that can be used for the conductive material.

  As described above, the conductive portion 33 in the conductive particle 31 has a two-layer structure. The conductive particle 41 shown in FIG. 6 has a solder part 42 as a single-layer conductive part. The conductive particles 41 include base particles 32 and solder portions 42 disposed on the surfaces of the base particles 32.

  Examples of the substrate particles include resin particles, inorganic particles excluding metal particles, organic-inorganic hybrid particles, and metal particles. The substrate particles are preferably substrate particles excluding metal particles, and more preferably resin particles, inorganic particles excluding metal particles, or organic-inorganic hybrid particles. The base particle may have a core and a shell disposed on the surface of the core, or may be a core-shell particle. The core may be an organic core, and the shell may be an inorganic shell.

  The substrate particles are more preferably resin particles or organic-inorganic hybrid particles, and may be resin particles or organic-inorganic hybrid particles. When connecting between electrodes using the said electroconductive particle, after arrange | positioning the said electroconductive particle between electrodes, the said electroconductive particle is compressed by crimping | bonding. When the substrate particles are resin particles, the conductive particles are easily deformed during the pressure bonding, and the contact area between the conductive particles and the electrode is increased. For this reason, the conduction | electrical_connection reliability between electrodes can be improved further.

  Various organic materials are suitably used as the resin for forming the resin particles. Examples of the resin for forming the resin particles include polyolefin resins such as polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyvinylidene chloride, polyisobutylene, and polybutadiene; acrylic resins such as polymethyl methacrylate and polymethyl acrylate; polycarbonate , Polyamide, phenol formaldehyde resin, melamine formaldehyde resin, benzoguanamine formaldehyde resin, urea formaldehyde resin, phenol resin, melamine resin, benzoguanamine resin, urea resin, epoxy resin, unsaturated polyester resin, saturated polyester resin, polyethylene terephthalate, polysulfone, polyphenylene oxide , Polyacetal, polyimide, polyamideimide, polyether ether Tons, polyether sulfone, divinyl benzene polymer, and divinylbenzene copolymer, and the like. Examples of the divinylbenzene copolymer include divinylbenzene-styrene copolymer and divinylbenzene- (meth) acrylic acid ester copolymer. Since the hardness of the resin particles can be easily controlled within a suitable range, the resin for forming the resin particles is a polymer obtained by polymerizing one or more polymerizable monomers having an ethylenically unsaturated group. It is preferably a coalescence.

  When the resin particles are obtained by polymerizing a polymerizable monomer having an ethylenically unsaturated group, the polymerizable monomer having an ethylenically unsaturated group may be a non-crosslinkable monomer or a crosslinkable monomer. And the monomer.

  Examples of the non-crosslinkable monomer include styrene monomers such as styrene and α-methylstyrene; carboxyl group-containing monomers such as (meth) acrylic acid, maleic acid, and maleic anhydride; (Meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, cetyl (meth) acrylate, stearyl (meth) acrylate, cyclohexyl ( Alkyl (meth) acrylate compounds such as meth) acrylate and isobornyl (meth) acrylate; 2-hydroxyethyl (meth) acrylate, glycerol (meth) acrylate, polyoxyethylene (meth) acrylate, glycidyl (meth) acrylate, etc. Elemental atom-containing (meth) acrylate compounds; nitrile-containing monomers such as (meth) acrylonitrile; vinyl ether compounds such as methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether; acids such as vinyl acetate, vinyl butyrate, vinyl laurate, vinyl stearate Vinyl ester compounds; unsaturated hydrocarbons such as ethylene, propylene, isoprene, and butadiene; halogen-containing monomers such as trifluoromethyl (meth) acrylate, pentafluoroethyl (meth) acrylate, vinyl chloride, vinyl fluoride, and chlorostyrene Etc.

  Examples of the crosslinkable monomer include tetramethylolmethane tetra (meth) acrylate, tetramethylolmethane tri (meth) acrylate, tetramethylolmethane di (meth) acrylate, trimethylolpropane tri (meth) acrylate, and dipenta Erythritol hexa (meth) acrylate, dipentaerythritol penta (meth) acrylate, glycerol tri (meth) acrylate, glycerol di (meth) acrylate, (poly) ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) Polyfunctional (meth) acrylate compounds such as acrylate, (poly) tetramethylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate; triallyl (iso) cyanide Silane-containing monomers such as salts, triallyl trimellitate, divinylbenzene, diallyl phthalate, diallylacrylamide, diallyl ether, γ- (meth) acryloxypropyltrimethoxysilane, trimethoxysilylstyrene, vinyltrimethoxysilane, etc. Is mentioned.

  The term “(meth) acrylate” refers to acrylate and methacrylate. The term “(meth) acryl” refers to acrylic and methacrylic. The term “(meth) acryloyl” refers to acryloyl and methacryloyl.

  The resin particles can be obtained by polymerizing the polymerizable monomer having an ethylenically unsaturated group by a known method. Examples of this method include a method of suspension polymerization in the presence of a radical polymerization initiator, and a method of polymerizing by swelling a monomer together with a radical polymerization initiator using non-crosslinked seed particles.

  In the case where the substrate particles are inorganic particles or organic-inorganic hybrid particles excluding metal, examples of the inorganic material for forming the substrate particles include silica, alumina, barium titanate, zirconia, and carbon black. The inorganic substance is preferably not a metal. The particles formed from the silica are not particularly limited. For example, after forming a crosslinked polymer particle by hydrolyzing a silicon compound having two or more hydrolyzable alkoxysilyl groups, firing may be performed as necessary. The particle | grains obtained by performing are mentioned. Examples of the organic / inorganic hybrid particles include organic / inorganic hybrid particles formed of a crosslinked alkoxysilyl polymer and an acrylic resin.

  The organic-inorganic hybrid particles are preferably core-shell type organic-inorganic hybrid particles having a core and a shell disposed on the surface of the core. The core is preferably an organic core. The shell is preferably an inorganic shell. From the viewpoint of further reducing the connection resistance between the electrodes, the base material particles are preferably organic-inorganic hybrid particles having an organic core and an inorganic shell disposed on the surface of the organic core.

  Examples of the material for forming the organic core include the resin for forming the resin particles described above.

  Examples of the material for forming the inorganic shell include inorganic substances for forming the above-described base material particles. The material for forming the inorganic shell is preferably silica. The inorganic shell is preferably formed on the surface of the core by forming a metal alkoxide into a shell by a sol-gel method and then sintering the shell. The metal alkoxide is preferably a silane alkoxide. The inorganic shell is preferably formed of a silane alkoxide.

  The particle diameter of the core is preferably 0.5 μm or more, more preferably 1 μm or more, preferably 500 μm or less, more preferably 100 μm or less, still more preferably 50 μm or less, particularly preferably 20 μm or less, and most preferably 10 μm or less. It is. When the particle diameter of the core is not less than the above lower limit and not more than the above upper limit, conductive particles more suitable for electrical connection between electrodes can be obtained, and the base particles can be suitably used for the use of conductive particles. Become. For example, when the particle diameter of the core is not less than the lower limit and not more than the upper limit, when the electrodes are connected using the conductive particles, the contact area between the conductive particles and the electrodes is sufficiently large, and When the conductive portion is formed on the surface of the base particle, the aggregated conductive particles can be made difficult to be formed. In addition, the distance between the electrodes connected via the conductive particles does not become too large, and the conductive portion can be made difficult to peel from the surface of the base material particles.

  The particle diameter of the core means the diameter when the core is a true sphere, and the maximum diameter when the core is a shape other than the true sphere. Moreover, the particle diameter of a core means the average particle diameter which measured the core with arbitrary particle diameter measuring apparatuses. For example, a particle size distribution measuring apparatus using principles such as laser light scattering, electrical resistance value change, and image analysis after imaging can be used.

  The thickness of the shell is preferably 100 nm or more, more preferably 200 nm or more, preferably 5 μm or less, more preferably 3 μm or less. When the thickness of the shell is not less than the above lower limit and not more than the above upper limit, conductive particles more suitable for electrical connection between the electrodes can be obtained, and the base particles can be suitably used for the use of conductive particles. . The thickness of the shell is an average thickness per base particle. The thickness of the shell can be controlled by controlling the sol-gel method.

  When the substrate particles are metal particles, examples of the metal for forming the metal particles include silver, copper, nickel, silicon, gold, and titanium. When the base material particles are metal particles, the metal particles are preferably copper particles. However, the substrate particles are preferably not metal particles.

  The particle diameter of the substrate particles is preferably 0.1 μm or more, more preferably 1 μm or more, further preferably 1.5 μm or more, particularly preferably 2 μm or more, preferably 1000 μm or less, more preferably 500 μm or less, more More preferably, it is 300 μm or less, more preferably 50 μm or less, still more preferably 30 μm or less, particularly preferably 5 μm or less, and most preferably 3 μm or less. When the particle diameter of the base material particles is equal to or larger than the lower limit, the contact area between the conductive particles and the electrodes is increased, so that the conduction reliability between the electrodes can be further improved and the connection is made through the conductive particles. The connection resistance between the formed electrodes can be further reduced. When the particle diameter of the substrate particles is not more than the above upper limit, the conductive particles are easily compressed, the connection resistance between the electrodes can be further reduced, and the distance between the electrodes can be further reduced. it can.

  The particle diameter of the base particle indicates a diameter when the base particle is a true sphere, and indicates a maximum diameter when the base particle is not a true sphere.

  The particle diameter of the substrate particles is particularly preferably 2 μm or more and 5 μm or less. When the particle diameter of the substrate particles is in the range of 2 to 5 μm, the distance between the electrodes can be further reduced, and even when the thickness of the conductive layer is increased, small conductive particles can be obtained. .

  The method for forming the conductive part on the surface of the base particle and the method for forming the solder part on the surface of the base particle or the surface of the second conductive part are not particularly limited. Examples of the method for forming the conductive portion and the solder portion include a method by electroless plating, a method by electroplating, a method by physical collision, a method by mechanochemical reaction, a method by physical vapor deposition or physical adsorption, And a method of coating the surface of the substrate particles with a paste containing metal powder or metal powder and a binder. Electroless plating, electroplating or physical collision methods are preferred. Examples of the method by physical vapor deposition include methods such as vacuum vapor deposition, ion plating, and ion sputtering. Further, in the method based on the physical collision, for example, a sheeter composer (manufactured by Tokuju Kogakusha Co., Ltd.) or the like is used.

  The melting point of the substrate particles is preferably higher than the melting point of the conductive part. The melting point of the substrate particles is preferably higher than 160 ° C, more preferably higher than 300 ° C, still more preferably higher than 400 ° C, and particularly preferably higher than 450 ° C. The melting point of the substrate particles may be less than 400 ° C. The melting point of the substrate particles may be 160 ° C. or less. The softening point of the substrate particles is preferably 260 ° C. or higher. The softening point of the substrate particles may be less than 260 ° C.

  The conductive particles may have a single layer solder portion. The conductive particles may have a plurality of layers of conductive parts (solder part, second conductive part). That is, in the conductive particles, two or more conductive portions may be stacked. When the conductive part has two or more layers, the conductive particles preferably have solder on the outer surface portion of the conductive part.

  The solder is preferably a metal (low melting point metal) having a melting point of 450 ° C. or lower. The solder part is preferably a metal layer (low melting point metal layer) having a melting point of 450 ° C. or lower. The low melting point metal layer is a layer containing a low melting point metal. The solder in the conductive particles is preferably metal particles having a melting point of 450 ° C. or lower (low melting point metal particles). The low melting point metal particles are particles containing a low melting point metal. The low melting point metal is a metal having a melting point of 450 ° C. or lower. The melting point of the low melting point metal is preferably 300 ° C. or lower, more preferably 160 ° C. or lower.

  The solder in the conductive particles preferably contains tin. In 100% by weight of the metal contained in the solder part and 100% by weight of the metal contained in the solder in the conductive particles, the content of tin is preferably 30% by weight or more, more preferably 40% by weight or more, and still more preferably. It is 70% by weight or more, particularly preferably 90% by weight or more. When the content of tin in the solder in the conductive particles is not less than the above lower limit, the conduction reliability between the conductive particles and the electrode is further enhanced.

  The tin content is determined using a high frequency inductively coupled plasma optical emission spectrometer (“ICP-AES” manufactured by Horiba, Ltd.) or a fluorescent X-ray analyzer (“EDX-800HS” manufactured by Shimadzu). It can be measured.

  By using the conductive particles having the solder on the outer surface portion of the conductive portion, the solder is melted and joined to the electrodes, and the solder conducts between the electrodes. For example, since the solder and the electrode are not in point contact but in surface contact, the connection resistance is lowered. In addition, the use of conductive particles having solder on the outer surface of the conductive portion increases the bonding strength between the solder and the electrode, and as a result, the solder and the electrode are more unlikely to peel off, and the conduction reliability is effective. To be high.

  The low melting point metal constituting the solder part and the solder particles is not particularly limited. The low melting point metal is preferably tin or an alloy containing tin. Examples of the alloy include a tin-silver alloy, a tin-copper alloy, a tin-silver-copper alloy, a tin-bismuth alloy, a tin-zinc alloy, and a tin-indium alloy. The low melting point metal is preferably tin, a tin-silver alloy, a tin-silver-copper alloy, a tin-bismuth alloy, or a tin-indium alloy because of its excellent wettability with respect to the electrode. More preferred are a tin-bismuth alloy and a tin-indium alloy.

  The material constituting the solder (solder part) is preferably a filler material having a liquidus of 450 ° C. or lower based on JIS Z3001: Welding terms. Examples of the composition of the solder include a metal composition containing zinc, gold, silver, lead, copper, tin, bismuth, indium and the like. A tin-indium system (117 ° C eutectic) or a tin-bismuth system (139 ° C eutectic) that has a low melting point and is free of lead is preferable. That is, the solder preferably does not contain lead, and is preferably a solder containing tin and indium or a solder containing tin and bismuth.

  In order to further increase the bonding strength between the solder and the electrode, the solder in the conductive particles is nickel, copper, antimony, aluminum, zinc, iron, gold, titanium, phosphorus, germanium, tellurium, cobalt, bismuth, manganese. Further, it may contain a metal such as chromium, molybdenum and palladium. Moreover, from the viewpoint of further increasing the bonding strength between the solder and the electrode, the solder in the conductive particles preferably contains nickel, copper, antimony, aluminum, or zinc. From the viewpoint of further increasing the bonding strength between the solder and the electrode in the solder portion or the conductive particles, the content of these metals for increasing the bonding strength is preferably 0% in 100% by weight of the solder in the conductive particles. 0.0001% by weight or more, preferably 1% by weight or less.

  The melting point of the second conductive part is preferably higher than the melting point of the solder part. The melting point of the second conductive part is preferably more than 160 ° C, more preferably more than 300 ° C, still more preferably more than 400 ° C, still more preferably more than 450 ° C, particularly preferably more than 500 ° C, most preferably Preferably it exceeds 600 degreeC. Since the solder part has a low melting point, it melts during conductive connection. It is preferable that the second conductive portion does not melt during conductive connection. The conductive particles are preferably used by melting solder, preferably used by melting the solder part, and used without melting the solder part and melting the second conductive part. It is preferred that Since the melting point of the second conductive part is higher than the melting point of the solder part, it is possible to melt only the solder part without melting the second conductive part during conductive connection.

  The absolute value of the difference between the melting point of the solder part and the melting point of the second conductive part exceeds 0 ° C, preferably 5 ° C or more, more preferably 10 ° C or more, still more preferably 30 ° C or more, particularly preferably Is 50 ° C. or higher, most preferably 100 ° C. or higher.

  The second conductive part preferably contains a metal. The metal which comprises the said 2nd electroconductive part is not specifically limited. Examples of the metal include gold, silver, copper, platinum, palladium, zinc, lead, aluminum, cobalt, indium, nickel, chromium, titanium, antimony, bismuth, germanium and cadmium, and alloys thereof. Further, tin-doped indium oxide (ITO) may be used as the metal. As for the said metal, only 1 type may be used and 2 or more types may be used together.

  The second conductive portion is preferably a nickel layer, a palladium layer, a copper layer, or a gold layer, more preferably a nickel layer or a gold layer, and even more preferably a copper layer. The conductive particles preferably have a nickel layer, a palladium layer, a copper layer, or a gold layer, more preferably have a nickel layer or a gold layer, and still more preferably have a copper layer. By using the conductive particles having these preferable conductive parts for the connection between the electrodes, the connection resistance between the electrodes is further reduced. Moreover, a solder part can be more easily formed on the surface of these preferable conductive parts.

  The thickness of the solder part is preferably 0.005 μm or more, more preferably 0.01 μm or more, preferably 10 μm or less, more preferably 1 μm or less, and still more preferably 0.3 μm or less. When the thickness of the solder part is not less than the above lower limit and not more than the above upper limit, sufficient conductivity is obtained, and the conductive particles do not become too hard, and the conductive particles are sufficiently deformed at the time of connection between the electrodes. .

  The average particle diameter of the conductive particles is preferably 0.5 μm or more, more preferably 1 μm or more, further preferably 3 μm or more, particularly preferably 5 μm or more, preferably 100 μm or less, more preferably 40 μm or less, and much more. It is preferably 30 μm or less, more preferably 20 μm or less, particularly preferably 15 μm or less, and most preferably 10 μm or less. When the average particle diameter of the conductive particles is not less than the above lower limit and not more than the above upper limit, the solder in the conductive particles can be more efficiently arranged on the electrode. The average particle size of the conductive particles is particularly preferably 5 μm or more and 30 μm or less.

  The “average particle size” of the conductive particles indicates a number average particle size. The average particle diameter of the conductive particles is obtained, for example, by observing 50 arbitrary conductive particles with an electron microscope or an optical microscope, calculating an average value, or performing laser diffraction particle size distribution measurement.

  The variation coefficient of the particle diameter of the conductive particles is preferably 5% or more, more preferably 10% or more, preferably 40% or less, more preferably 30% or less. When the variation coefficient of the particle diameter is not less than the above lower limit and not more than the above upper limit, the solder in the conductive particles can be more efficiently arranged on the electrode. However, the coefficient of variation of the particle diameter of the conductive particles may be less than 5%.

  The coefficient of variation (CV value) can be measured as follows.

CV value (%) = (ρ / Dn) × 100
ρ: Standard deviation of particle diameter of conductive particles Dn: Average value of particle diameter of conductive particles

  The shape of the conductive particles is not particularly limited. The conductive particles may have a spherical shape or a shape other than a spherical shape such as a flat shape.

  The content of the conductive particles in 100% by weight of the conductive material is preferably 1% by weight or more, more preferably 2% by weight or more, still more preferably 10% by weight or more, particularly preferably 20% by weight or more, most preferably. It is 30% by weight or more, preferably 90% by weight or less, more preferably 80% by weight or less, still more preferably 60% by weight or less, and particularly preferably 50% by weight or less. When the content of the conductive particles is not less than the above lower limit and not more than the above upper limit, the solder in the conductive particles can be arranged more efficiently on the electrodes, and more solder in the conductive particles is arranged between the electrodes. It is easy to do and the conduction reliability is further increased. From the viewpoint of further improving the conduction reliability, the content of the conductive particles is preferably large.

(Thermosetting component)
The thermosetting component may contain a thermosetting compound that can be cured by heating, and a curing agent. Examples of the thermosetting compound include oxetane compounds, epoxy compounds, episulfide compounds, (meth) acrylic compounds, phenolic compounds, amino compounds, unsaturated polyester compounds, polyurethane compounds, silicone compounds, and polyimide compounds. From the viewpoint of further improving the curability and viscosity of the conductive material and further improving the conduction reliability, an epoxy compound or an episulfide compound is preferable, and an epoxy compound is more preferable. The thermosetting component preferably contains an epoxy compound. The thermosetting component preferably contains an epoxy compound and a curing agent. As for the said thermosetting component, only 1 type may be used and 2 or more types may be used together.

  From the viewpoint of further increasing the heat resistance of the cured product, the thermosetting compound preferably includes a thermosetting compound having an isocyanuric skeleton.

  Examples of the thermosetting compound having the above isocyanuric skeleton include triisocyanurate type epoxy compounds, etc., and TEPIC series (TEPIC-G, TEPIC-S, TEPIC-SS, TEPIC-HP, TEPIC-L, manufactured by Nissan Chemical Industries, Ltd. TEPIC-PAS, TEPIC-VL, TEPIC-UC) and the like.

  An aromatic epoxy compound is mentioned as said epoxy compound. Crystalline epoxy compounds such as resorcinol-type epoxy compounds, naphthalene-type epoxy compounds, biphenyl-type epoxy compounds, and benzophenone-type epoxy compounds are preferred. An epoxy compound that is solid at normal temperature (23 ° C.) and has a melting temperature equal to or lower than the melting point of the solder is preferable. The melting temperature is preferably 100 ° C. or lower, more preferably 80 ° C. or lower, and preferably 40 ° C. or higher. By using the preferable epoxy compound, the first connection target member and the second connection target are high when the connection target member is bonded to each other when the viscosity is high and acceleration is applied by impact such as conveyance. The displacement with respect to the member can be suppressed, and the viscosity of the conductive material can be greatly reduced by the heat at the time of curing, and the aggregation of the solder particles can be advanced efficiently.

  The content of the thermosetting compound in 100% by weight of the conductive material is preferably 20% by weight or more, more preferably 40% by weight or more, still more preferably 50% by weight or more, and preferably 99% by weight or less. Is 98% by weight or less, more preferably 90% by weight or less, and particularly preferably 80% by weight or less. When the content of the thermosetting compound is not less than the above lower limit and not more than the above upper limit, the solder is more efficiently arranged on the electrodes, further suppressing the displacement between the electrodes, and the conduction reliability between the electrodes. Can be further increased. From the viewpoint of further improving the impact resistance, it is preferable that the content of the thermosetting compound is large.

  The content of the epoxy compound in 100% by weight of the conductive material is preferably 20% by weight or more, more preferably 40% by weight or more, still more preferably 50% by weight or more, preferably 99% by weight or less, more preferably 98%. % By weight or less, more preferably 90% by weight or less, particularly preferably 80% by weight or less. When the content of the epoxy compound is not less than the above lower limit and not more than the above upper limit, the solder is more efficiently arranged on the electrodes, the positional deviation between the electrodes is further suppressed, and the conduction reliability between the electrodes is further improved. It can be further enhanced. From the viewpoint of further improving the impact resistance, it is preferable that the content of the epoxy compound is large.

  The curing agent is preferably a thermosetting agent that thermosets the thermosetting compound. Examples of the thermosetting agent include imidazole curing agents, amine curing agents, phenol curing agents, polythiol curing agents and other thiol curing agents, phosphonium salts, acid anhydrides, thermal cation initiators (thermal cation curing agents), and thermal radical generators. Etc. As for the said thermosetting agent, only 1 type may be used and 2 or more types may be used together.

  From the viewpoint of enabling the conductive material to be cured more rapidly at a low temperature, the thermosetting agent is preferably an imidazole curing agent, a thiol curing agent, or an amine curing agent, and more preferably a thiol curing agent. . Further, from the viewpoint of enhancing the storage stability when the thermosetting compound and the thermosetting agent are mixed, the thermosetting agent is preferably a latent curing agent. The latent curing agent is preferably a latent imidazole curing agent, a latent thiol curing agent, or a latent amine curing agent. In addition, the said thermosetting agent may be coat | covered with polymeric substances, such as a polyurethane resin or a polyester resin.

  The imidazole curing agent is not particularly limited, and 2-methylimidazole, 2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-phenylimidazolium trimellitate, 2, 4-Diamino-6- [2'-methylimidazolyl- (1 ')]-ethyl-s-triazine and 2,4-diamino-6- [2'-methylimidazolyl- (1')]-ethyl-s- Triazine isocyanuric acid adduct, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2-phenyl-4-benzyl-5-hydroxymethylimidazole, 2-paratoluyl- 4-methyl-5-hydroxymethylimidazole, 2-metatoluyl-4 The hydrogen at the 5-position of 1H-imidazole in methyl-5-hydroxymethylimidazole, 2-metatoluyl-4,5-dihydroxymethylimidazole, 2-paratoluyl-4,5-dihydroxymethylimidazole, etc. is a hydroxymethyl group, and 2 And imidazole compounds in which the hydrogen at the position is substituted with a phenyl group or a toluyl group. From the viewpoint of allowing the conductive material to be cured more rapidly at a low temperature, the imidazole compound includes 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2- P-Toluyl-4-methyl-5-hydroxymethylimidazole, 2-methatoruyl-4-methyl-5-hydroxymethylimidazole, 2-methatoruyl-4,5-dihydroxymethylimidazole, 2-paratoluyl-4,5-dihydroxymethylimidazole It is preferable that

  The thiol curing agent is not particularly limited, and examples thereof include trimethylolpropane tris-3-mercaptopropionate, pentaerythritol tetrakis-3-mercaptopropionate, and dipentaerythritol hexa-3-mercaptopropionate. .

  The amine curing agent is not particularly limited, and hexamethylene diamine, octamethylene diamine, decamethylene diamine, 3,9-bis (3-aminopropyl) -2,4,8,10-tetraspiro [5.5]. Examples include undecane, bis (4-aminocyclohexyl) methane, metaphenylenediamine, and diaminodiphenylsulfone.

  Examples of the phosphonium salt include tetranormal butylphosphonium bromide, tetranormal butylphosphonium OO diethyldithiophosphoric acid, methyltributylphosphonium dimethyl phosphate, tetranormal butylphosphonium benzotriazole, tetranormal butylphosphonium tetrafluoroborate, and tetranormal butylphosphonium. Examples include tetraphenylborate.

  The thermal cation initiator is not particularly limited, and examples thereof include iodonium cation curing agents, oxonium cation curing agents, and sulfonium cation curing agents. Examples of the iodonium-based cationic curing agent include bis (4-tert-butylphenyl) iodonium hexafluorophosphate. Examples of the oxonium-based cationic curing agent include trimethyloxonium tetrafluoroborate. Examples of the sulfonium-based cationic curing agent include tri-p-tolylsulfonium hexafluorophosphate.

  The thermal radical generator is not particularly limited, and examples thereof include azo compounds and organic peroxides. Examples of the azo compound include azobisisobutyronitrile (AIBN). Examples of the organic peroxide include di-tert-butyl peroxide and methyl ethyl ketone peroxide.

  The reaction initiation temperature of the thermosetting agent is preferably 50 ° C or higher, more preferably 70 ° C or higher, still more preferably 80 ° C or higher, preferably 250 ° C or lower, more preferably 200 ° C or lower, still more preferably 150 ° C or lower, Especially preferably, it is 140 degrees C or less. When the reaction start temperature of the thermosetting agent is not less than the above lower limit and not more than the above upper limit, the solder is more efficiently arranged on the electrode. The reaction initiation temperature of the thermosetting agent is particularly preferably 80 ° C. or higher and 140 ° C. or lower.

  From the viewpoint of more efficiently arranging the solder on the electrode, the reaction initiation temperature of the thermosetting agent is preferably higher than the melting point of the solder in the first conductive particles, and is preferably 5 ° C. or higher. More preferably, it is more preferably 10 ° C. or higher.

  The reaction start temperature of the thermosetting agent means a temperature at which the exothermic peak of DSC starts to rise.

  The content of the thermosetting agent is not particularly limited. The content of the thermosetting agent is preferably 0.01 parts by weight or more, more preferably 1 part by weight or more, preferably 200 parts by weight or less, more preferably 100 parts by weight with respect to 100 parts by weight of the thermosetting compound. Part or less, more preferably 75 parts by weight or less. When the content of the thermosetting agent is not less than the above lower limit, it is easy to sufficiently cure the conductive material. When the content of the thermosetting agent is not more than the above upper limit, it is difficult for an excess thermosetting agent that did not participate in curing after curing to remain, and the heat resistance of the cured product is further enhanced.

(flux)
The conductive material includes a flux. By using flux, the solder can be more effectively placed on the electrode. The flux is not particularly limited. As the flux, a flux generally used for soldering or the like can be used.

  Examples of the flux include zinc chloride, a mixture of zinc chloride and an inorganic halide, a mixture of zinc chloride and an inorganic acid, a molten salt, phosphoric acid, a derivative of phosphoric acid, an organic halide, hydrazine, an amine compound, and an organic compound. Examples include acid and rosin. As for the said flux, only 1 type may be used and 2 or more types may be used together.

  Examples of the molten salt include ammonium chloride. Examples of the organic acid include lactic acid, citric acid, stearic acid, glutamic acid, and glutaric acid. Examples of the pine resin include activated pine resin and non-activated pine resin. The flux is preferably an organic acid having two or more carboxyl groups, pine resin. The flux may be an organic acid having two or more carboxyl groups, or pine resin. By using an organic acid having two or more carboxyl groups, pine resin, the conduction reliability between the electrodes is further enhanced.

  Examples of the organic acid having two or more carboxyl groups include succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, and sebacic acid.

  Examples of the amine compound include cyclohexylamine, dicyclohexylamine, benzylamine, benzhydrylamine, imidazole, benzimidazole, phenylimidazole, carboxybenzimidazole, benzotriazole, carboxybenzotriazole, and the like.

  The rosin is a rosin composed mainly of abietic acid. Examples of the rosins include abietic acid and acrylic modified rosin. The flux is preferably a rosin, and more preferably abietic acid. By using this preferable flux, the conduction reliability between the electrodes is further enhanced.

  The active temperature (melting point) of the flux is preferably 50 ° C. or higher, more preferably 70 ° C. or higher, further preferably 80 ° C. or higher, preferably 200 ° C. or lower, more preferably 190 ° C. or lower, even more preferably 160 ° C. or lower. More preferably, it is 150 ° C. or less, and still more preferably 140 ° C. or less. When the active temperature of the flux is not less than the above lower limit and not more than the above upper limit, the flux effect is more effectively exhibited, and the conductive particles are more efficiently arranged on the electrode. The active temperature (melting point) of the flux is preferably 80 ° C. or higher and 190 ° C. or lower. The activation temperature (melting point) of the flux is particularly preferably 80 ° C. or higher and 140 ° C. or lower.

  The flux having an active temperature (melting point) of 80 ° C. or higher and 190 ° C. or lower includes succinic acid (melting point 186 ° C.), glutaric acid (melting point 96 ° C.), adipic acid (melting point 152 ° C.), pimelic acid (melting point) 104 ° C.), dicarboxylic acids such as suberic acid (melting point 142 ° C.), benzoic acid (melting point 122 ° C.), malic acid (melting point 130 ° C.) and the like.

  The boiling point of the flux is preferably 200 ° C. or lower.

  From the viewpoint of more efficiently arranging the solder on the electrode, the melting point of the flux is preferably higher than the melting point of the solder particles, more preferably 5 ° C or higher, and more preferably 10 ° C or higher. preferable.

  From the viewpoint of more efficiently arranging the solder on the electrode, the melting point of the flux is preferably higher than the reaction start temperature of the thermosetting agent, more preferably 5 ° C or higher, more preferably 10 ° C or higher. More preferably.

  The said flux may be disperse | distributed in the electrically-conductive material and may adhere on the surface of electroconductive particle.

  When the melting point of the flux is higher than the melting point of the solder, the conductive particles can be efficiently aggregated on the electrode portion. This is because, when heat is applied at the time of joining, when the electrode formed on the connection target member is compared with the portion of the connection target member around the electrode, the thermal conductivity of the electrode portion is Due to the fact that it is higher than the thermal conductivity, the temperature rise of the electrode portion is fast. At the stage where the melting point of the conductive particles is exceeded, the inside of the conductive particles dissolves, but the oxide film formed on the surface does not reach the melting point (activation temperature) of the flux and is not removed. In this state, since the temperature of the electrode portion first reaches the melting point (activation temperature) of the flux, the oxide film on the surface of the conductive particles that has come preferentially on the electrode is removed, and the conductive particles are removed from the surface of the electrode. Can spread over the top. Thereby, electroconductive particle can be efficiently aggregated on an electrode.

  The flux is preferably a flux that releases cations by heating. By using a flux that releases cations by heating, the conductive particles can be arranged more efficiently on the electrode.

  Examples of the flux that releases cations by the heating include the thermal cation initiator (thermal cation curing agent).

  The content of the flux in 100% by weight of the conductive material is preferably 0.5% by weight or more, preferably 30% by weight or less, and more preferably 25% by weight or less. The conductive material may not contain flux. When the flux content is not less than the above lower limit and not more than the above upper limit, it becomes more difficult to form an oxide film on the surface of the solder and the electrode, and the oxide film formed on the surface of the solder and the electrode is more effective. Can be removed.

(Water absorbent)
The conductive material includes a water absorbing agent. The water absorbing agent is not particularly limited. As the water-absorbing agent, compounds generally used as a desiccant, a hygroscopic agent, a dehydrating agent and the like can be used.

  From the viewpoint of more efficiently removing water in the conductive material, the conductive material preferably contains a propylene compound, an acetylene compound, or an acid anhydride as the water absorbing agent. As for the said water absorbing agent, only 1 type may be used and 2 or more types may be used together.

  From the viewpoint of more efficiently removing water in the conductive material, the conductive material preferably contains an acid anhydride as the water-absorbing agent. The conductive material may contain a propylene compound or an acetylene compound as the water absorbing agent.

  The propylene compound and acetylene compound are preferably acrylic polymers. The acrylic polymer is preferably a polymer of (meth) acrylic acid or (meth) acrylate. The acrylic polymer is more preferably a polymer of a salt of (meth) acrylic acid.

  The acrylic polymer may be a copolymer copolymerized with a polymerizable monomer having an ethylenically unsaturated group when the polymer is polymerized.

  The acrylic polymer may not have a functional group, and may have one or more functional groups such as a hydroxyl group, a carboxyl group, an epoxy group, an alkyl group, or an alkoxysilyl group.

  The (meth) acrylate may be a single-tube acrylate or a bifunctional or higher polyfunctional acrylate.

  Examples of the single-tube acrylate include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, cetyl ( Alkyl (meth) acrylate compounds such as (meth) acrylate, stearyl (meth) acrylate, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate; 2-hydroxyethyl (meth) acrylate, glycerol (meth) acrylate, polyoxyethylene (meta) ) Oxygen atom-containing (meth) acrylate compounds such as acrylate and glycidyl (meth) acrylate; Nitrile-containing monomers such as (meth) acrylonitrile; Trifluoromethyl (meth) acrylate Halogen-containing (meth) acrylate compounds such as pentafluoroethyl (meth) acrylate; 2-methyl-3-butyl-2-yl (meth) acrylate, 1-ethynylcyclohexyl (meth) acrylate, 2-propynyl (meth) acrylate And (meth) acrylate compounds having a triple bond such as As for the said single tuberability (meth) acrylate, only 1 type may be used and 2 or more types may be used together.

  Examples of the polyfunctional (meth) acrylate include tripropylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, and tripropylene glycol di ( (Meth) acrylate, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, modified bisphenol A di (meth) acrylate, tricyclodecandi Bifunctional (meth) acrylates such as methanol di (meth) acrylate; pentaerythritol tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolpropane etoxy Trifunctional (meth) acrylates such as tri (meth) acrylate, polyether tri (meth) acrylate, glycerin propoxytri (meth) acrylate, etc .; pentaerythritol tetra (meth) acrylate, pentaerythritol ethoxytetra (meth) acrylate, ditrimethylolpropane Tetrafunctional (meth) acrylates such as tetra (meth) acrylate; dipentaerythritol penta (meth) acrylate, propionic acid-modified dipentaerythritol penta (meth) acrylate, dipentaerythritol monohydroxypenta (meth) acrylate, dipentaerythritol hexa Mention may be made of (meth) acrylates having 5 or more functional groups such as (meth) acrylates. As for the said polyfunctional (meth) acrylate, only 1 type may be used and 2 or more types may be used together.

  The polymerizable monomer having an ethylenically unsaturated group may be a non-crosslinkable monomer or a crosslinkable monomer. Examples of the polymerizable monomer having an ethylenically unsaturated group include the compounds described above.

  The acrylic polymer can be obtained by polymerizing by a known method. Examples of this method include emulsion polymerization and solution polymerization.

  Examples of the acid anhydride include Ricacid Series (Ricacid TH, Ricacid HT-1A, Ricacid HH, Ricacid MH-700, Ricacid MH-700G, Ricacid MH, Ricacid HNA-100, Ricacid TMEG- S, Ricacid TMEG-100, Ricacid TMEG-200, Ricacid TMEG-500, Ricacid TMEG-600, Ricacid TMTA-C, Ricacid MTA-15, etc.), Mitsubishi Chemical Corporation "YH306", DIC Corporation "EPICLON B-570H" And “HN-2200”, “HN-2000”, “HN-5500”, and “MHAC-P” manufactured by Hitachi Chemical.

  As for the said acid anhydride, only 1 type may be used and 2 or more types may be used together.

  Moisture is generated when the flux melts and the oxide film of the electrode and solder is removed. From the viewpoint of more efficiently removing moisture generated at high temperatures, the acid anhydride is preferably in a liquid state at a flux melting temperature of −10 ° C.

  From the viewpoint of more effectively removing moisture in the conductive material and further improving the conduction reliability and insulation reliability between the electrodes, the water absorption amount of the water absorbing agent at 70 ° C. is preferably 0.03 ml / g. As described above, more preferably 0.05 ml / g. The water absorption of the water absorbing agent at 70 ° C. may be 1 ml / g or less, or 0.2 ml / g or less.

  The water absorption can be measured as follows.

  1 g of water absorbent is placed in an environment of 70 ° C. and 90% relative humidity. After 1 hour, the water absorption amount can be calculated from the weight increase of 1 g of the water absorbing agent.

  From the viewpoint of further effectively removing moisture in the conductive material and further improving the conduction reliability and insulation reliability between the electrodes, the content of the water absorbing agent in 100% by weight of the upper conductive material is preferably It is 0.1% by weight or more, more preferably 0.3% by weight or more, preferably 10% by weight or less, more preferably 5% by weight or less.

(Insulating particles)
The conductive material preferably contains insulating particles. In the conductive material, the insulating particles may not be attached to the surface of the conductive particles. In the conductive material, the insulating particles are preferably present apart from the conductive particles. By including the insulating particles, it is possible to accurately control the interval between the connection target members connected by the cured material of the conductive material and the interval between the connection target members connected by the solder in the conductive particles. .

  The average particle diameter of the insulating particles is preferably 10 μm or more, more preferably 20 μm or more, still more preferably 25 μm or more, preferably 100 μm or less, more preferably 75 μm or less, and even more preferably 50 μm or less. When the average particle diameter of the insulating particles is not less than the above lower limit and not more than the above upper limit, the interval between the connection target members connected by the cured material of the conductive material, and between the connection target members connected by the solder in the conductive particles The interval becomes even more moderate.

  Examples of the material of the insulating particles include an insulating resin and an insulating inorganic substance.

  Specific examples of the insulating resin that is the material of the insulating particles include polyolefins, (meth) acrylate polymers, (meth) acrylate copolymers, block polymers, thermoplastic resins, crosslinked thermoplastic resins, heat Examples thereof include curable resins and water-soluble resins.

  Examples of the polyolefins include polyethylene, ethylene-vinyl acetate copolymer, and ethylene-acrylic acid ester copolymer. Examples of the (meth) acrylate polymer include polymethyl (meth) acrylate, polyethyl (meth) acrylate, and polybutyl (meth) acrylate. Examples of the block polymer include polystyrene, styrene-acrylic acid ester copolymer, SB type styrene-butadiene block copolymer, SBS type styrene-butadiene block copolymer, and hydrogenated products thereof. Examples of the thermoplastic resin include vinyl polymers and vinyl copolymers. As said thermosetting resin, an epoxy resin, a phenol resin, a melamine resin, etc. are mentioned. Examples of the water-soluble resin include polyvinyl alcohol, polyacrylic acid, polyacrylamide, polyvinyl pyrrolidone, polyethylene oxide, and methyl cellulose. A water-soluble resin is preferable, and polyvinyl alcohol is more preferable.

  Specific examples of the insulating inorganic material that is the material of the insulating particles include silica and organic-inorganic hybrid particles. The particles formed from the silica are not particularly limited. For example, after forming a crosslinked polymer particle by hydrolyzing a silicon compound having two or more hydrolyzable alkoxysilyl groups, firing may be performed as necessary. The particle | grains obtained by performing are mentioned. Examples of the organic / inorganic hybrid particles include organic / inorganic hybrid particles formed of a crosslinked alkoxysilyl polymer and an acrylic resin.

  The content of the insulating particles in 100% by weight of the conductive material is preferably 0.1% by weight or more, more preferably 0.5% by weight or more, preferably 10% by weight or less, more preferably 5% by weight or less. is there. The conductive material may not contain insulating particles. When the content of the insulating particles is not less than the above lower limit and not more than the above upper limit, the interval between the connection target members connected by the cured material of the conductive material and the interval between the connection target members connected by the solder are more appropriate. become.

(Other ingredients)
The conductive material may be, for example, a coupling agent, a light-shielding agent, a reactive diluent, an antifoaming agent, a leveling agent, a filler, an extender, a softening agent, a plasticizer, a polymerization catalyst, a curing catalyst, or a coloring agent. Various additives such as an agent, an antioxidant, a heat stabilizer, a light stabilizer, an ultraviolet absorber, a lubricant, an antistatic agent and a flame retardant may be included.

(Connection structure and method of manufacturing connection structure)
A connection structure according to the present invention includes a first connection target member having at least one first electrode on the surface, a second connection target member having at least one second electrode on the surface, and the first The connection object member and the connection part which has connected the said 2nd connection object member are provided. In the connection structure according to the present invention, the material of the connection portion is the conductive material described above. The connecting portion is a cured product of the conductive material described above. The connecting portion is formed of the conductive material described above. In the connection structure according to the present invention, the first electrode and the second electrode are electrically connected by a solder portion in the connection portion.

  The manufacturing method of the connection structure according to the present invention includes the step of disposing the conductive material on the surface of the first connection target member having at least one first electrode on the surface, using the conductive material described above. The second connection object member having at least one second electrode on the surface opposite to the first connection object member side of the conductive material, the first electrode and the second electrode The step of disposing the electrodes so as to face each other, and heating the conductive material above the melting point of the solder in the conductive particles and above the curing temperature of the thermosetting component, whereby the first connection object member and the above A connection portion connecting the second connection target member is formed of the conductive material, and the first electrode and the second electrode are electrically connected by a solder portion in the connection portion. Connecting.

  In the connection structure according to the present invention and the method for manufacturing the connection structure, since a specific conductive material is used, the conductive particles are likely to gather between the first electrode and the second electrode, and solder is used as the electrode. (Line) can be arranged efficiently. In addition, a part of the solder is difficult to be disposed in a region (space) where no electrode is formed, and the amount of solder disposed in a region where no electrode is formed can be considerably reduced. Therefore, the conduction reliability between the first electrode and the second electrode can be improved. In addition, it is possible to prevent electrical connection between laterally adjacent electrodes that should not be connected, and to improve insulation reliability.

  Moreover, in order to arrange the solder efficiently on the electrode and considerably reduce the amount of the solder arranged in the region where the electrode is not formed, the conductive material is not a conductive film but a conductive paste. It is preferable.

  The thickness of the solder part between the electrodes is preferably 10 μm or more, more preferably 20 μm or more, preferably 100 μm or less, more preferably 80 μm or less. The solder wetted area on the surface of the electrode (area where the solder is in contact with 100% of the exposed area of the electrode) is preferably 50% or more, more preferably 60% or more, still more preferably 70% or more, preferably 100. % Or less.

  Hereinafter, specific embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a cross-sectional view schematically showing a connection structure obtained using a conductive material according to an embodiment of the present invention.

  The connection structure 1 shown in FIG. 1 is a connection that connects a first connection target member 2, a second connection target member 3, and the first connection target member 2 and the second connection target member 3. Part 4. The connection part 4 is formed of the conductive material described above. In the present embodiment, a conductive paste is used as the conductive material. In this embodiment, solder particles are used as the conductive particles.

  The connection portion 4 includes a solder portion 4A in which a plurality of solder particles are gathered and joined to each other, and a cured product portion 4B in which a thermosetting component is thermally cured.

  The first connection target member 2 has a plurality of first electrodes 2a on the surface (upper surface). The second connection target member 3 has a plurality of second electrodes 3a on the surface (lower surface). The first electrode 2a and the second electrode 3a are electrically connected by the solder portion 4A. Therefore, the first connection target member 2 and the second connection target member 3 are electrically connected by the solder portion 4A. In the connection portion 4, no solder particles are present in a region (cured product portion 4B portion) different from the solder portion 4A gathered between the first electrode 2a and the second electrode 3a. In an area different from the solder part 4A (hardened product part 4B part), there are no solder particles separated from the solder part 4A. If the amount is small, solder particles may exist in a region (cured product portion 4B portion) different from the solder portion 4A gathered between the first electrode 2a and the second electrode 3a.

  As shown in FIG. 1, in the connection structure 1, a plurality of solder particles gather between the first electrode 2 a and the second electrode 3 a, and after the plurality of solder particles melt, After the electrode surface wets and spreads, it solidifies to form the solder portion 4A. For this reason, the connection area of 4 A of solder parts and the 1st electrode 2a, and 4 A of solder parts, and the 2nd electrode 3a becomes large. For this reason, the conduction | electrical_connection reliability and connection reliability in the connection structure 1 become high. In addition, when a flux is contained in the conductive material, the flux is generally gradually deactivated by heating.

  In addition, in the connection structure 1 shown in FIG. 1, all the solder parts 4A are located in the area | region which the 1st, 2nd electrodes 2a and 3a oppose. The connection structure 1X of the modification shown in FIG. 3 is different from the connection structure 1 shown in FIG. 1 only in the connection portion 4X. The connection part 4X has the solder part 4XA and the hardened | cured material part 4XB. As in the connection structure 1X, most of the solder portions 4XA are located in regions where the first and second electrodes 2a and 3a are opposed to each other, and a part of the solder portion 4XA is first and second. You may protrude to the side from the area | region which electrode 2a, 3a has opposed. The solder part 4XA protruding laterally from the region where the first and second electrodes 2a and 3a are opposed is a part of the solder part 4XA and is not a solder separated from the solder part 4XA. In the present embodiment, the amount of solder away from the solder portion can be reduced, but the solder away from the solder portion may exist in the cured product portion.

  If the amount of solder particles used is reduced, the connection structure 1 can be easily obtained. If the amount of the solder particles used is increased, it becomes easy to obtain the connection structure 1X.

  From the viewpoint of further improving the conduction reliability, the portion where the first electrode and the second electrode face each other in the stacking direction of the first electrode, the connection portion, and the second electrode is seen. Sometimes, 50% or more (more preferably 60% or more, still more preferably 70% or more, particularly preferably 80% or more) out of 100% of the area where the first electrode and the second electrode face each other. , Most preferably 90% or more), the solder portion in the connection portion is preferably disposed.

  Next, an example of a method for manufacturing the connection structure 1 using the conductive material according to the embodiment of the present invention will be described.

  First, the 1st connection object member 2 which has the 1st electrode 2a on the surface (upper surface) is prepared. Next, as shown in FIG. 2A, a conductive paste 11 including a thermosetting component 11 </ b> B and a plurality of solder particles 11 </ b> A that are conductive particles is disposed on the surface of the first connection target member 2. (First step). The used conductive paste contains a thermosetting compound and a thermosetting agent as the thermosetting component 11B.

  The conductive paste 11 is disposed on the surface of the first connection target member 2 on which the first electrode 2a is provided. After the conductive paste 11 is disposed, the solder particles 11A are disposed both on the first electrode 2a (line) and on a region (space) where the first electrode 2a is not formed.

  The arrangement method of the conductive paste 11 is not particularly limited, and examples thereof include application with a dispenser, screen printing, and ejection with an inkjet device.

  Moreover, the 2nd connection object member 3 which has the 2nd electrode 3a on the surface (lower surface) is prepared. Next, as shown in FIG. 2B, in the conductive paste 11 on the surface of the first connection target member 2, on the surface of the conductive paste 11 opposite to the first connection target member 2 side, The 2nd connection object member 3 is arrange | positioned (2nd process). On the surface of the conductive paste 11, the second connection target member 3 is disposed from the second electrode 3a side. At this time, the first electrode 2a and the second electrode 3a are opposed to each other.

  Next, the conductive paste 11 is heated above the melting point of the solder particles 11A (third step). Preferably, the conductive paste 11 is heated above the curing temperature of the thermosetting component 11B (thermosetting compound). At the time of this heating, the solder particles 11A that existed in the region where no electrode is formed gather between the first electrode 2a and the second electrode 3a (self-aggregation effect). When the conductive paste is used instead of the conductive film, the solder particles 11A are effectively collected between the first electrode 2a and the second electrode 3a. Also, the solder particles 11A are melted and joined together. Further, the thermosetting component 11B is thermoset. As a result, as shown in FIG. 2C, the connection portion 4 connecting the first connection target member 2 and the second connection target member 3 is formed with the conductive paste 11. The connection part 4 is formed by the conductive paste 11, the solder part 4A is formed by joining a plurality of solder particles 11A, and the cured part 4B is formed by thermosetting the thermosetting component 11B. If the solder particles 11A are sufficiently moved, the first electrode 2a and the second electrode are moved after the movement of the solder particles 11A not located between the first electrode 2a and the second electrode 3a starts. It is not necessary to keep the temperature constant until the movement of the solder particles 11A is completed.

  In the present embodiment, it is preferable that no pressure is applied in the second step and the third step. In this case, the weight of the second connection target member 3 is added to the conductive paste 11. For this reason, when the connection part 4 is formed, the solder particles 11A are effectively collected between the first electrode 2a and the second electrode 3a. It should be noted that if pressure is applied in at least one of the second step and the third step, the action of the solder particles 11A trying to collect between the first electrode and the second electrode is hindered. The tendency to be higher. This has been found by the inventor.

  Moreover, in this embodiment, since pressurization is not performed, when the second connection target member is superimposed on the first connection target member to which the conductive paste is applied, the electrode of the first connection target member Even when the first connection target member and the second connection target member are overlapped in a state where the alignment of the electrodes of the second connection target member is shifted, the shift is corrected and the first connection target member is corrected. Can be connected to the electrode of the second connection target member (self-alignment effect). This is because the molten solder self-aggregated between the electrode of the first connection target member and the electrode of the second connection target member is the electrode of the first connection target member and the electrode of the second connection target member. As the area where the solder and the other components of the conductive material are in contact with each other is minimized, the energy becomes more stable. Therefore, the force that makes the connection structure with alignment, which is the connection structure with the smallest area, works. Because. At this time, it is desirable that the conductive paste is not cured and that the viscosity of components other than the conductive particles of the conductive paste is sufficiently low at that temperature and time.

  In this way, the connection structure 1 shown in FIG. 1 is obtained. The second step and the third step may be performed continuously. Moreover, after performing the said 2nd process, the laminated body of the obtained 1st connection object member 2, the electrically conductive paste 11, and the 2nd connection object member 3 is moved to a heating part, and said 3rd said You may perform a process. In order to perform the heating, the laminate may be disposed on a heating member, or the laminate may be disposed in a heated space.

  The heating temperature in the third step is preferably 140 ° C. or higher, more preferably 160 ° C. or higher, preferably 450 ° C. or lower, more preferably 250 ° C. or lower, and further preferably 200 ° C. or lower.

  As a heating method in the third step, a method of heating the entire connection structure using a reflow furnace or an oven above the melting point of the solder and the curing temperature of the thermosetting compound, or a connection structure The method of heating only the connection part of these is mentioned.

  The said 1st, 2nd connection object member is not specifically limited. Specifically as said 1st, 2nd connection object member, electronic components, such as a semiconductor chip, a semiconductor package, LED chip, LED package, a capacitor | condenser, a diode, and a resin film, a printed circuit board, a flexible printed circuit board, flexible Examples thereof include electronic components such as circuit boards such as flat cables, rigid flexible boards, glass epoxy boards, and glass boards. The first and second connection target members are preferably electronic components.

  It is preferable that at least one of the first connection target member and the second connection target member is a resin film, a flexible printed board, a flexible flat cable, or a rigid flexible board. The second connection target member is preferably a resin film, a flexible printed board, a flexible flat cable, or a rigid flexible board. Resin films, flexible printed boards, flexible flat cables, and rigid flexible boards have the property of being highly flexible and relatively lightweight. When a conductive film is used for connection of such a connection object member, there exists a tendency for a solder not to gather on an electrode. On the other hand, by using a conductive paste, even if a resin film, a flexible printed circuit board, a flexible flat cable, or a rigid flexible circuit board is used, the conductive reliability between the electrodes can be efficiently collected by collecting the solder on the electrodes. Can be sufficiently increased. When using a resin film, a flexible printed circuit board, a flexible flat cable, or a rigid flexible circuit board, compared to the case of using other connection target members such as a semiconductor chip, the conduction reliability between the electrodes by not applying pressure is improved. The improvement effect can be obtained more effectively.

  Examples of the electrode provided on the connection target member include metal electrodes such as a gold electrode, a nickel electrode, a tin electrode, an aluminum electrode, a copper electrode, a molybdenum electrode, a silver electrode, a SUS electrode, and a tungsten electrode. When the connection object member is a flexible printed board, the electrode is preferably a gold electrode, a nickel electrode, a tin electrode, a silver electrode, or a copper electrode. When the connection target member is a glass substrate, the electrode is preferably an aluminum electrode, a copper electrode, a molybdenum electrode, a silver electrode, or a tungsten electrode. In addition, when the said electrode is an aluminum electrode, the electrode formed only with aluminum may be sufficient and the electrode by which the aluminum layer was laminated | stacked on the surface of the metal oxide layer may be sufficient. Examples of the material for the metal oxide layer include indium oxide doped with a trivalent metal element and zinc oxide doped with a trivalent metal element. Examples of the trivalent metal element include Sn, Al, and Ga.

  The first electrode and the second electrode are preferably arranged in an area array or a peripheral. The effect of the present invention is more effectively exhibited when the electrodes are arranged on the surface of an area array or a peripheral. The area array is a structure in which electrodes are arranged in a grid pattern on the surface where the electrodes of the connection target members are arranged. The peripheral is a structure in which electrodes are arranged on the outer periphery of a connection target member. In the case of a structure in which the electrodes are arranged in a comb shape, the solder particles only have to be aggregated along the direction perpendicular to the comb, whereas in the above structure, the surface on which the electrodes are arranged is uniform over the entire surface. Since it is necessary for the solder particles to agglomerate, the amount of solder tends to be non-uniform in the conventional method, whereas in the method of the present invention, the effects of the present invention are more effectively exhibited.

  Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples. The present invention is not limited only to the following examples.

Thermosetting component (epoxy compound):
"YL980" manufactured by Mitsubishi Chemical Corporation, bisphenol A type epoxy resin "TEPIC-HP" manufactured by Nissan Chemical Industries, Ltd., triisocyanurate type epoxy resin

Thermosetting component (curing agent):
“HXA3922HP” manufactured by Asahi Kasei Chemicals Co., Ltd., microcapsule type latent curing agent “2MA-OK” manufactured by Shikoku Chemicals Co., Ltd., 2,4-diamino-6- [2′-methylimidazolyl- (1 ′)]-ethyl-s -Triazine isocyanuric acid adduct

flux:
Glutaric acid benzylamine salt

Water absorbent:
“Magnesium sulfate” manufactured by Wako Pure Chemical Industries, Ltd.
“Calcium carbonate” manufactured by Wako Pure Chemical Industries, Ltd.
“YH306” manufactured by Mitsubishi Chemical Corporation, 3,4-dimethyl-6- (2-methyl-1-propenyl) -4-cyclohexene-1,2-dicarboxylic acid anhydride “Licacid MH”, 4- Methylhexahydrophthalic anhydride “Rikacid TMEG-600” manufactured by Shin Nippon Rika Co., Ltd., ethylene glycol bisanhydro trimellitate

Conductive particles:
Conductive particle 1 (SnBi solder particle, melting point 139 ° C., solder particle body selected from “Sn42Bi58” manufactured by Mitsui Kinzoku Co., Ltd., surface-treated anionic polymer 1 solder particle, average particle diameter: 10 μm, CV value : 10%, polymer molecular weight: Mw = 5000)

(Method for producing conductive particles 1)
200 g of solder particle body, 40 g of glutaric acid, and 70 g of acetone are weighed in a three-necked flask, and then dibutyltin oxide, which is a dehydration condensation catalyst of hydroxyl groups on the surface of the solder particle body and carboxyl groups of adipic acid, is added. 3 g was added and reacted at 60 ° C. for 4 hours. Thereafter, the solder particles were collected by filtration.

  The collected solder particles, 50 g of adipic acid, 200 g of toluene, and 0.3 g of paratoluenesulfonic acid were weighed in a three-necked flask and reacted at 120 ° C. for 3 hours while evacuating and refluxing. . At this time, the reaction was carried out while removing water produced by dehydration condensation using a Dean-Stark extraction device.

  Thereafter, the solder particles were collected by filtration, washed with hexane, and dried. Then, after crushing the obtained electroconductive particle with a ball mill, it sieved so that it might become a predetermined CV value.

Weight average molecular weight of anionic polymer 1:
The weight average molecular weight of the anionic polymer 1 on the surface of the first conductive particles was obtained by dissolving the solder using 0.1N hydrochloric acid, collecting the polymer by filtration, and determining by GPC.

CV value of particle diameter of conductive particles:
The CV value was measured with a laser diffraction particle size distribution analyzer (“LA-920” manufactured by Horiba, Ltd.).

(Examples 1-7 and Comparative Example 1)
(1) Preparation of anisotropic conductive paste The components shown in Table 1 below are blended in the blending amounts shown in Table 1 below, and the anisotropic conductive paste is obtained by mixing and defoaming with a planetary stirrer. It was.

(2) Production of First Connection Structure (Area Array Substrate) As a first connection target member, a 250 μm copper electrode with a pitch of 400 μm is provided on the surface of a semiconductor chip body (size 5 × 5 mm, thickness 0.4 mm). A semiconductor chip was prepared, which is arranged in an area array and has a passivation film (polyimide, thickness 5 μm, opening diameter of electrode part 200 μm) formed on the outermost surface. The number of copper electrodes is 10 × 10 in total per 100 semiconductor chips.

  As the second connection target member, the same pattern is formed on the surface of the glass epoxy substrate main body (size 20 × 20 mm, thickness 1.2 mm, material FR-4) with respect to the electrode of the first connection target member. The glass epoxy board | substrate with which the copper resist is arrange | positioned and the soldering resist film is formed in the area | region where the copper electrode is not arrange | positioned was prepared. The level difference between the surface of the copper electrode and the surface of the solder resist film is 15 μm, and the solder resist film protrudes from the copper electrode.

  The anisotropic conductive paste immediately after fabrication was applied to the upper surface of the glass epoxy substrate so as to have a thickness of 100 μm, thereby forming an anisotropic conductive paste layer. Next, a semiconductor chip was laminated on the upper surface of the anisotropic conductive paste layer so that the electrodes face each other. The weight of the semiconductor chip is added to the anisotropic conductive paste layer. From this state, the anisotropic conductive paste layer was heated so that the temperature became 139 ° C. (melting point of solder) after 5 seconds from the start of temperature increase. Furthermore, 15 seconds after the start of temperature increase, the anisotropic conductive paste layer was heated to 160 ° C. to cure the anisotropic conductive paste layer, and a connection structure was obtained. No pressure was applied during heating.

(3) Production of Second Connection Structure (Peripheral Substrate) As a first connection target member, a 250 μm copper electrode with a pitch of 400 μm is provided on the surface of a semiconductor chip body (size 5 × 5 mm, thickness 0.4 mm). A semiconductor chip was prepared, which is arranged (peripheral) on the outer periphery of the chip and has a passivation film (polyimide, thickness 5 μm, opening diameter of electrode part 200 μm) formed on the outermost surface. The number of copper electrodes is a total of 36 pieces of 10 × 4 sides per semiconductor chip.

  As the second connection target member, the same pattern is formed on the surface of the glass epoxy substrate main body (size 20 × 20 mm, thickness 1.2 mm, material FR-4) with respect to the electrode of the first connection target member. The glass epoxy board | substrate with which the copper resist is arrange | positioned and the soldering resist film is formed in the area | region where the copper electrode is not arrange | positioned was prepared. The level difference between the surface of the copper electrode and the surface of the solder resist film is 15 μm, and the solder resist film protrudes from the copper electrode.

  The anisotropic conductive paste immediately after fabrication was applied to the peripheral portion on the upper surface of the glass epoxy substrate so as to have a thickness of 100 μm to form an anisotropic conductive paste layer. Next, a semiconductor chip was laminated on the upper surface of the anisotropic conductive paste layer so that the electrodes face each other. The weight of the semiconductor chip is added to the anisotropic conductive paste layer. From this state, the anisotropic conductive paste layer was heated so that the temperature became 139 ° C. (melting point of solder) after 5 seconds from the start of temperature increase. Furthermore, 15 seconds after the start of temperature increase, the anisotropic conductive paste layer was heated to 160 ° C. to cure the anisotropic conductive paste layer, and a connection structure was obtained. No pressure was applied during heating.

(Evaluation)
(1) Viscosity at 25 ° C. (η25)
The viscosity (η25) at 25 ° C. of the anisotropic conductive paste immediately after production was measured under the conditions of 25 ° C. and 5 rpm using an E-type viscometer (“TVE22L” manufactured by Toki Sangyo Co., Ltd.).

(2) Melting point of solder particles—viscosity at -10 ° C. (η-10)
An anisotropic conductive paste immediately after production is measured using STRESSTECH (manufactured by EOLOGICA) under the conditions of strain control 1 rad, frequency 1 Hz, temperature rising rate 20 ° C./min, measurement temperature range 40 ° C. to melting point of solder particles ° C. did. In this measurement, the viscosity of the solder particles at a melting point of −10 ° C. was read and used as the viscosity of the anisotropic conductive paste at the melting point of the solder particles of −10 ° C.

(3) Solder placement accuracy on the electrode In the obtained first and second connection structures, the first electrode and the second electrode in the stacking direction of the first electrode, the connection portion, and the second electrode. When the portion facing each other is viewed, the ratio X of the area where the solder portion in the connection portion is arranged in 100% of the area facing the first electrode and the second electrode is evaluated. did. The placement accuracy of the solder on the electrode was determined according to the following criteria.

[Criteria for solder placement accuracy on electrodes]
○○: Ratio X is 70% or more ○: Ratio X is 60% or more and less than 70% Δ: Ratio X is 50% or more and less than 60% X: Ratio X is less than 50%

(4) Conduction reliability between upper and lower electrodes In the obtained first and second connection structures (n = 15), the connection resistance between the upper and lower electrodes was measured by a four-terminal method. The average value of connection resistance was calculated. Note that the connection resistance can be obtained by measuring the voltage when a constant current is passed from the relationship of voltage = current × resistance. The conduction reliability was determined according to the following criteria.

[Judgment criteria for conduction reliability]
○○: Average value of connection resistance is 8.0Ω or less ○: Average value of connection resistance exceeds 8.0Ω and 10.0Ω or less △: Average value of connection resistance exceeds 10.0Ω and 15.0Ω or less × : Average connection resistance exceeds 15.0Ω

(5) Insulation reliability between adjacent electrodes In the obtained first and second connection structures (n = 15), they are left in an atmosphere of 85 ° C. and 85% humidity for 100 hours and then adjacent. 5V was applied between the electrodes, and the resistance value was measured at 25 locations. Insulation reliability was judged according to the following criteria.

[Criteria for insulation reliability]
◯: Average value of connection resistance is 10 ⁷ Ω or more ○: Average value of connection resistance is 10 ⁶ Ω or more, less than 10 ⁷ Ω △: Average value of connection resistance is 10 ⁵ Ω or more, less than 10 ⁶ Ω ×: Connection The average resistance is less than 10 ⁵ Ω

(6) Arrangement accuracy maintainability An anisotropic conductive paste immediately after fabrication was applied to a thickness of 100 μm, and after forming an anisotropic conductive paste layer, it was left as it was for 12 hours before stacking semiconductor chips. Except for the above, the first ′ and second ′ connection structures were produced in the same manner as the first and second connection structures.

  In the obtained 1 ′ and 2 ′ connection structures, the portions where the first electrode and the second electrode face each other in the stacking direction of the first electrode, the connection portion, and the second electrode were seen. Occasionally, the placement accuracy maintainability was evaluated from the ratio X of the area where the solder portion in the connection portion is placed in the area of 100% of the portion where the first electrode and the second electrode face each other. Placement accuracy maintenance was determined according to the following criteria.

[Criteria for placement accuracy maintenance]
○○: Ratio X is 70% or more ○: Ratio X is 60% or more and less than 70% Δ: Ratio X is 50% or more and less than 60% X: Ratio X is less than 50%

  The results are shown in Table 1 below.

  Even when a flexible printed board, a resin film, a flexible flat cable, and a rigid flexible board were used, the same tendency was observed.

DESCRIPTION OF SYMBOLS 1,1X ... Connection structure 2 ... 1st connection object member 2a ... 1st electrode 3 ... 2nd connection object member 3a ... 2nd electrode 4, 4X ... Connection part 4A, 4XA ... Solder part 4B, 4XB ... Cured part 11 ... Conductive paste 11A ... Solder particles (conductive particles)
11B ... thermosetting component 21 ... conductive particles (solder particles)
31 ... Conductive particles 32 ... Base particle 33 ... Conductive part (conductive part having solder)
33A ... second conductive part 33B ... solder part 41 ... conductive particles 42 ... solder part

Claims (13)

A plurality of conductive particles having solder on the outer surface portion of the conductive portion,
A thermosetting component;
With flux,
A conductive material comprising a water absorbing agent.   The conductive material according to claim 1, wherein a content of the water-absorbing agent is 0.1 wt% or more and 5 wt% or less in 100 wt% of the conductive material.   The conductive material according to claim 1 or 2, wherein a water absorption amount of the water absorbing agent at 70 ° C is 0.03 ml / g or more.   The conductive material according to claim 1, comprising a propylene compound, an acetylene compound, or an acid anhydride as the water absorbing agent.   The conductive material according to claim 4, comprising an acid anhydride as the water absorbing agent.   The conductive material according to claim 5, wherein the acid anhydride is liquid at a flux melting temperature of −10 ° C. 6.   The conductive material according to claim 1, wherein the thermosetting component includes a thermosetting compound and a curing agent.   The conductive material according to claim 7, wherein the curing agent is a thiol curing agent.   The conductive material according to claim 1, which is a conductive paste. A first connection target member having at least one first electrode on its surface;
A second connection target member having at least one second electrode on its surface;
A connection portion connecting the first connection target member and the second connection target member;
The material of the connection portion is the conductive material according to any one of claims 1 to 9,
A connection structure in which the first electrode and the second electrode are electrically connected by a solder portion in the connection portion.   When the first electrode and the second electrode face each other in the stacking direction of the first electrode, the connection portion, and the second electrode, the first electrode and the second electrode 11. The connection structure according to claim 10, wherein a solder portion in the connection portion is disposed in 50% or more of an area of 100% of a portion facing the two electrodes. Using the conductive material according to claim 1, disposing the conductive material on a surface of a first connection target member having at least one first electrode on the surface;
On the surface opposite to the first connection target member side of the conductive material, a second connection target member having at least one second electrode on the surface, the first electrode and the second electrode And a step of arranging so as to face each other,
The first connection target member and the second connection target member are connected by heating the conductive material at a temperature equal to or higher than the melting point of the solder in the conductive particles and equal to or higher than the curing temperature of the thermosetting component. And a step of electrically connecting the first electrode and the second electrode with a solder portion in the connection portion, wherein the connection portion is formed of the conductive material. Method.   When the first electrode and the second electrode face each other in the stacking direction of the first electrode, the connection portion, and the second electrode, the first electrode and the second electrode The manufacturing method of the connection structure of Claim 12 which obtains the connection structure by which the solder part in the said connection part is arrange | positioned in 50% or more in 100% of the area of the part which opposes two electrodes .

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