JP2018195525A - Conductive material, connection structure, and manufacturing method of connection structure - Google Patents

Abstract

To provide a conductive material capable of effectively reducing gaps between target members for connection, and effectively enhancing storage stability of the conductive material.SOLUTION: The conductive material contains a first curable compound, a curing agent and a solder particle, contains a second curable compound or no second curable compound, an absolute value of difference between a SP value of the first curable compound and a SP value of the curing agent is 2 or more, an absolute value of difference of a SP value of the second curable compound and the SP value of the curing agent is less than 2, the content of the first curable compound in total 100 wt.% of the first curable compound and the second curable compound is 5 wt.% or more and d90 of the solder particle in a particle size distribution based on volume of the solder particle is 10 μm or less.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a conductive material containing solder particles. 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.

  Patent Document 1 listed below discloses a conductive material including a plurality of conductive particles having solder on the outer surface portion of a conductive portion, a thermosetting compound, and an acid anhydride thermosetting agent. The viscosity of the conductive material at 50 ° C. is 10 Pa · s or more and 200 Pa · s or less. Patent Document 1 does not describe any SP values for the thermosetting compound and the acid anhydride thermosetting agent.

  Patent Document 2 below discloses an adhesive composition for connecting a solar battery cell and a circuit board. The adhesive composition includes a thermosetting resin composition containing an acrylic compound and a thermosetting resin. The number of double bond equivalents of the acrylic compound is 90 or more and 500 or less. Content of the said acrylic compound is 5 mass% or more and 50 mass% or less with respect to 100 mass% of the said thermosetting resin compositions. The acid value of the said thermosetting resin composition is 5 mgKOH / g or more and 50 mgKOH / g or less. In Patent Document 2, the adhesive composition may contain a lead-free solder powder having a melting point of 240 ° C. or less and a curing agent. Patent Document 2 does not describe any SP values for the thermosetting resin and the curing agent.

WO2017 / 033935A1 JP 2013-76045 A

  In recent years, there has been a demand for a connection structure with a small gap between connection target members in order to cope with high-speed transmission of electronic devices. In order to reduce the gap between the members to be connected, it is necessary to thin the solder bumps used for electrical connection between the electrodes, and it is necessary to reduce the particle diameter of the solder particles used for the solder bumps. In the conventional conductive material, when the particle size of the solder particles or the conductive particles is reduced, the storage stability (pot life) of the conductive material may be deteriorated. In the conventional conductive material, it is difficult to achieve both the reduction of the gap between the connection target members and the enhancement of the storage stability of the conductive material.

  An object of the present invention is to provide a conductive material that can effectively reduce a gap between members to be connected and can effectively improve the storage stability of the conductive material. 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, the conductive material includes a first curable compound, a curing agent, and solder particles, and the conductive material does not include or includes the second curable compound. The absolute value of the difference between the SP value of the first curable compound and the SP value of the curing agent is 2 or more, and the SP value of the second curable compound and the SP value of the curing agent The absolute value of the difference is less than 2, and the content of the first curable compound is 5% by weight or more in a total of 100% by weight of the first curable compound and the second curable compound. In the particle size distribution on the volume basis of the solder particles, a conductive material in which d90 of the solder particles is 10 μm or less is provided.

  In a specific aspect of the conductive material according to the present invention, the conductive material includes the second curable compound, and the total amount of the first curable compound and the second curable compound is 100% by weight. The content of the first curable compound is 90% by weight or less.

  In a specific aspect of the conductive material according to the present invention, the content of the second curable compound is 10% in a total of 100% by weight of the first curable compound and the second curable compound. % Or more.

  On the specific situation with the electrically conductive material which concerns on this invention, the absolute value of the difference of SP value of a said 1st sclerosing | hardenable compound and SP value of the said hardening | curing agent is 5.5 or less.

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

  In a specific aspect of the conductive material according to the present invention, the first curable compound is an aliphatic compound.

  In a specific aspect of the conductive material according to the present invention, the first curable compound is an aliphatic epoxy compound.

  On the specific situation with the electrically-conductive material which concerns on this invention, the said electrically-conductive material contains an organophosphorus compound.

  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 a first electrode on the surface, a second connection target member having a second electrode on the surface, the first connection target member, A connecting portion connecting the second connection target member, wherein the material of the connecting portion is the conductive material described above, and the first electrode and the second electrode are the connecting portion. A connection structure is provided that is electrically connected by a solder portion therein.

  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 the first electrode on the surface; On the surface opposite to the first connection target member side, the second connection target member having the second electrode on the surface is arranged so that the first electrode and the second electrode face each other. Forming a connection portion connecting the first connection target member and the second connection target member with the conductive material by heating the conductive material to a temperature equal to or higher than the melting point of the solder particles; And the manufacturing method of a connection structure provided with the process of electrically connecting a said 1st electrode and a said 2nd electrode with the solder part in the said connection part is provided.

  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 is a conductive material including a first curable compound, a curing agent, and solder particles, and the conductive material does not include or includes the second curable compound, The absolute value of the difference between the SP value of the first curable compound and the SP value of the curing agent is 2 or more, and the difference between the SP value of the second curable compound and the SP value of the curing agent Is less than 2, and the total content of the first curable compound and the second curable compound is 100% by weight, and the content of the first curable compound is 5% by weight or more. In addition, in the particle size distribution on the volume basis of the solder particles, since the d90 of the solder particles is 10 μm or less, the gap between the connection target members can be effectively reduced, and the storage stability of the conductive material can be reduced. Sexually can be enhanced effectively.

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.

  Details of the present invention will be described below.

(Conductive material)
The conductive material according to the present invention includes a first curable compound, a curing agent, and solder particles. The conductive material according to the present invention does not contain or contains the second curable compound. In the conductive material according to the present invention, the absolute value of the difference between the SP value of the first curable compound and the SP value of the curing agent is 2 or more. In the conductive material according to the present invention, the absolute value of the difference between the SP value of the second curable compound and the SP value of the curing agent is less than 2. In the conductive material according to the present invention, the content of the first curable compound is 5% by weight or more in a total of 100% by weight of the first curable compound and the second curable compound. In the conductive material according to the present invention, in the particle size distribution on the volume basis of the solder particles, d90 of the solder particles is 10 μm or less.

  In this invention, since said structure is provided, the gap between connection object members can be made small effectively, and the storage stability of an electrically-conductive material can be improved effectively.

  In order to reduce the gap between the connection target members of the connection structure, it is necessary to thin the solder bumps used for electrical connection between the electrodes, and it is necessary to reduce the particle size of the solder particles used for the solder bumps. There is. The present inventors have found that the storage stability (pot life) of the conductive material deteriorates as the particle size of the solder particles decreases. As a result of intensive studies to suppress deterioration of the storage stability of the conductive material, the present inventors have adopted the above-described configuration using a specific curable compound and a specific curing agent, thereby enabling It has been found that even when the particle size is reduced, the storage stability of the conductive material can be effectively increased. In this invention, since said structure is provided, both reducing the gap between connection object members and improving the storage stability of an electroconductive material can be made to make compatible.

  Further, when the connection structure is manufactured, the conductive material may be left for a certain period of time before the conductive material is electrically connected after the conductive material is disposed on the connection target member such as a substrate by screen printing or the like. Since the conventional conductive material cannot increase the storage stability (pot life), for example, if the conductive material is left for a certain period after the conductive material is disposed, the conductive material thickens and solder particles are formed on the electrodes. It cannot arrange | position efficiently and the conduction | electrical_connection reliability between electrodes may also fall. In the present invention, the above-described configuration is adopted, and the storage stability (pot life) of the conductive material can be effectively increased. Therefore, even if the conductive material is left for a certain period after being disposed, Thickening can be prevented, solder particles can be efficiently arranged on the electrodes, and the conduction reliability between the electrodes can be sufficiently enhanced.

  Further, in the present invention, since the above-described configuration is provided, when the electrodes are electrically connected, the plurality of solder particles are likely to gather between the upper and lower electrodes, and the plurality of solder particles are attached to the electrode ( Line). Moreover, it is difficult for some of the plurality of solder particles to be disposed in a region (space) where no electrode is formed, and the amount of solder particles disposed in a region where no electrode is formed can be considerably reduced. Therefore, the conduction reliability between the electrodes 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.

  Furthermore, in the present invention, it is possible to prevent positional deviation 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 in a state of misalignment, the electrodes can be connected by correcting the misalignment (self-alignment effect).

  From the viewpoint of more efficiently arranging the solder on the electrode, the conductive material is preferably liquid at 25 ° C., and preferably a conductive paste.

  Even when the conductive material is left for a certain period of time, from the viewpoint of more efficiently arranging the solder on the electrode and from the viewpoint of further effectively increasing the storage stability of the conductive material, The viscosity (η25) is preferably 20 Pa · s or more, more preferably 30 Pa · s or more, preferably 400 Pa · s or less, more preferably 300 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, for example, using an E-type viscometer (“TVE22L” manufactured by Toki Sangyo Co., Ltd.) and the like at 25 ° C. and 5 rpm.

  The conductive material can be 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 more efficiently disposing the solder on the electrode, the conductive material is preferably a conductive paste. 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. In the present specification, “(meth) acryl” means one or both of “acryl” and “methacryl”.

(Solder particles)
As for the said solder particle, both a center part and an outer surface are formed with the solder. The solder particles are particles in which both the central portion and the outer surface are solder. In place of the solder particles, when conductive particles including base particles formed from a material other than solder and solder portions arranged on the surface of the base particles are used, the conductive particles are conductive on the electrodes. Particles are difficult to collect. Moreover, in the said electroconductive particle, since the solder joint property of electroconductive particles is low, there exists a tendency for the electroconductive particle which moved on the electrode to move out of an electrode easily, and also has the effect of suppressing the position shift between electrodes. Tend to be lower.

  The solder is preferably a metal (low melting point metal) having a melting point of 450 ° C. or lower. The solder particles are preferably metal particles (low melting point metal particles) having a melting point of 450 ° C. or lower. 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 particles are preferably low melting point solder having a melting point of less than 150 ° C.

  The solder particles preferably contain tin. The content of tin in 100% by weight of metal contained in the solder particles is preferably 30% by weight or more, more preferably 40% by weight or more, still more preferably 70% by weight or more, and particularly preferably 90% by weight or more. . When the content of tin in the solder particles is equal to or higher than the lower limit, the connection reliability between the solder portion 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). Can be measured.

  By using the solder particles, the solder is melted and joined to the electrodes, and the solder portion conducts between the electrodes. For example, since the solder portion and the electrode are not in point contact but in surface contact, the connection resistance is lowered. Moreover, as a result of the use of the solder particles, the bonding strength between the solder part and the electrode is increased. As a result, peeling between the solder part and the electrode is less likely to occur, and the conduction reliability and the connection reliability are further improved.

  The low melting point metal constituting 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 solder particles are preferably a filler material having a liquidus line of 450 ° C. or lower based on JIS Z3001: welding terms. Examples of the composition of the solder particles include metal compositions 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 particles preferably do not contain lead, and preferably contain tin and indium, or contain tin and bismuth.

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

  In the conductive material according to the present invention, in the particle size distribution on the volume basis of the solder particles, d90 of the solder particles is 10 μm or less. From the viewpoint of further effectively reducing the gap between the connection target members, in the particle size distribution on the volume basis of the solder particles, d90 of the solder particles is preferably 6 μm or less, more preferably 4 μm or less. The lower limit of d90 of the solder particles is not particularly limited. The d90 of the solder particles may be 0.5 μm or more. Moreover, in the particle size distribution on the volume basis of the solder particles, when the d90 of the solder particles is equal to or less than the upper limit, the gap between the connection target members is further reduced.

  In addition, d90 of the said solder particle is a particle diameter of a solder particle when the cumulative volume of a solder particle is 90%. The d90 of the solder particles can be calculated from the particle size distribution on a volume basis.

  The particle size distribution on the volume basis of the solder particles is determined using a laser diffraction particle size distribution measuring apparatus. Examples of the laser diffraction particle size distribution measuring apparatus include “Mastersizer 3000” manufactured by Malvern.

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

  The content of the solder particles in 100% by weight of the conductive material is preferably 1% by weight or more, more preferably 2% by weight or more, further preferably 10% by weight or more, particularly preferably 20% by weight or more, and most preferably. It is 30% by weight or more, preferably 90% by weight or less, more preferably 80% by weight or less, and further preferably 70% by weight or less. When the content of the solder particles is not less than the above lower limit and not more than the above upper limit, the solder particles can be arranged more efficiently on the electrodes, and it is easy to arrange a lot of solder between the electrodes, The conduction reliability is further increased. From the viewpoint of further improving the conduction reliability, it is preferable that the content of the solder particles is large.

(First curable compound and second curable compound)
The first curable compound is not particularly limited. A known curable compound can be used as the first curable compound. The first curable compound may be a photocurable compound or a thermosetting compound. From the viewpoint of further effectively reducing the gap between the members to be connected and from the viewpoint of further effectively increasing the storage stability of the conductive material, the first curable compound may be an aliphatic compound. preferable.

  The conductive material does not contain or contains the second curable compound. The conductive material may or may not contain the second curable compound. From the viewpoint of further effectively increasing the connection reliability of the connection target members connected by the conductive material, the conductive material preferably contains the second curable compound.

  The second curable compound is not particularly limited. As the second curable compound, a known insulating curable compound is used. The second curable compound may be a photocurable compound or a thermosetting compound.

  From the viewpoint of further effectively increasing the connection reliability of the connection target members connected by the conductive material and from the viewpoint of further effectively increasing the storage stability of the conductive material, the first curable compound is a thermal compound. A curable compound is preferred.

  From the viewpoint of more effectively increasing the connection reliability of the connection target member connected by the conductive material and from the viewpoint of further effectively increasing the storage stability of the conductive material, the second curable compound is a A curable compound is preferred.

  The thermosetting compound is a compound that can be cured by heating. 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 more effectively increasing the connection reliability of the connection target member connected by the conductive material, and from the viewpoint of further effectively increasing the storage stability of the conductive material, the thermosetting compound is an epoxy compound or It is preferably an episulfide compound, and more preferably an epoxy compound. As for the said thermosetting compound, only 1 type may be used and 2 or more types may be used together.

  The epoxy compound is a compound having at least one epoxy group. Examples of the epoxy compound include bisphenol A type epoxy compound, bisphenol F type epoxy compound, bisphenol S type epoxy compound, phenol novolac type epoxy compound, biphenyl type epoxy compound, biphenyl novolac type epoxy compound, biphenol type epoxy compound, naphthalene type epoxy compound. Fluorene type epoxy compound, phenol aralkyl type epoxy compound, naphthol aralkyl type epoxy compound, dicyclopentadiene type epoxy compound, anthracene type epoxy compound, epoxy compound having adamantane skeleton, epoxy compound having tricyclodecane skeleton, naphthylene ether type Examples thereof include an epoxy compound and an epoxy compound having a triazine nucleus in the skeleton. As for the said epoxy compound, only 1 type may be used and 2 or more types may be used together.

  The epoxy compound is liquid or solid at normal temperature (23 ° C.), and when the epoxy compound is solid at normal temperature, the melting temperature of the epoxy compound is preferably equal to or lower than the melting point of the solder particles.

  From the viewpoint of further effectively increasing the connection reliability of the connection target members connected by the conductive material and from the viewpoint of further effectively increasing the storage stability of the conductive material, the first curable compound is an epoxy. A compound is preferable, and an aliphatic epoxy compound is more preferable.

  From the viewpoint of more effectively increasing the connection reliability of the connection target members connected by the conductive material, and from the viewpoint of further effectively increasing the storage stability of the conductive material, the second curable compound is an epoxy. A compound is preferred.

  In the conductive material according to the present invention, the content of the first curable compound is 5% by weight or more in a total of 100% by weight of the first curable compound and the second curable compound. Of the total of 100% by weight of the first curable compound and the second curable compound, the content of the first curable compound is preferably 5% by weight or more, more preferably 15% by weight or more. Yes, preferably 90% by weight or less, more preferably 70% by weight or less. When the content of the first curable compound is not less than the above lower limit and not more than the above upper limit, the gap between the connection target members can be further effectively reduced, and the storage stability of the conductive material is further improved. Can be effectively increased. Further, when the content of the first curable compound is not more than the above upper limit, the gel fraction of the cured product is increased, and the gap retention is further enhanced due to the cured product portion of the connection structure. Become.

  Of the total of 100% by weight of the first curable compound and the second curable compound, the content of the second curable compound is preferably 10% by weight or more, more preferably 30% by weight or more. Yes, preferably 95% by weight or less, more preferably 85% by weight or less. When the content of the second curable compound is not less than the lower limit and not more than the upper limit, the connection reliability of the connection target member connected by the conductive material is further effectively increased, and the storage stability of the conductive material is increased. It is possible to increase the property even more effectively.

  In 100% by weight of the conductive material, the content of the first curable compound is preferably 0.5% by weight or more, more preferably 2.25% by weight or more, and preferably 36% by weight or less. Is 21% by weight or less. When the content of the first curable compound is not less than the above lower limit and not more than the above upper limit, the connection reliability of the connection target member connected by the conductive material is further effectively increased, and the storage stability of the conductive material is increased. It is possible to increase the property even more effectively.

  In 100% by weight of the conductive material, the content of the second curable compound is preferably 1% by weight or more, more preferably 4.5% by weight or more, preferably 38% by weight or less, more preferably 25%. .5% by weight or less. When the content of the second curable compound is not less than the lower limit and not more than the upper limit, the connection reliability of the connection target member connected by the conductive material is further effectively increased, and the storage stability of the conductive material is increased. It is possible to increase the property even more effectively.

(Curing agent)
The said hardening | curing agent is not specifically limited. The curing agent cures the first curable compound and the second curable compound. The curing agent may be a thermosetting agent or a photopolymerization initiator. As for the said hardening | curing agent, only 1 type may be used and 2 or more types may be used together.

  In the conductive material according to the present invention, the absolute value of the difference between the SP value of the first curable compound and the SP value of the curing agent is 2 or more. From the viewpoint of further effectively reducing the gap between the members to be connected and from the viewpoint of further effectively increasing the storage stability of the conductive material, the SP value of the first curable compound and the SP of the curing agent are used. The absolute value of the difference from the value is preferably 2.2 or more, more preferably 2.6 or more, preferably 5.5 or less, more preferably 4.3 or less. In addition, when the absolute value of the difference between the SP value of the first curable compound and the SP value of the curing agent is equal to or higher than the lower limit, the storage stability of the conductive material can be effectively increased, and the conductive Even if the material is left for a certain period after being placed, it is possible to prevent thickening of the conductive material, to efficiently place the solder particles on the electrodes, and to sufficiently enhance the conduction reliability between the electrodes. .

  In the conductive material according to the present invention, the absolute value of the difference between the SP value of the second curable compound and the SP value of the curing agent is less than 2. From the viewpoint of further effectively reducing the gap between the members to be connected and from the viewpoint of further effectively improving the storage stability of the conductive material, the SP value of the second curable compound and the SP of the curing agent. The absolute value of the difference from the value is preferably 1.9 or less, more preferably 1.5 or less. The lower limit of the absolute value of the difference between the SP of the second curable compound and the SP of the curing agent is not particularly limited. The absolute value of the difference between the SP of the second curable compound and the SP of the curing agent may be 0 or more.

  From the viewpoint of further effectively reducing the gap between the members to be connected and from the viewpoint of further effectively increasing the storage stability of the conductive material, the curing agent is preferably a thermosetting agent.

  The said thermosetting agent thermosets a thermosetting compound. Examples of the thermosetting agent include an imidazole curing agent, a phenol curing agent, a thiol curing agent, an amine curing agent, an acid anhydride curing agent, a thermal cation curing agent, and a thermal radical generator. From the viewpoint of further effectively reducing the gap between the members to be connected and from the viewpoint of further effectively improving the storage stability of the conductive material, the thermosetting agent is preferably an acid anhydride curing agent. . As for the said thermosetting agent, only 1 type may be used and 2 or more types may be used together.

  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- Examples include triazine isocyanuric acid adducts.

  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.

  The acid anhydride curing agent is not particularly limited and can be widely used as long as it is an acid anhydride used as a curing agent for a thermosetting compound such as an epoxy compound. Examples of the acid anhydride curing agent include phthalic anhydride, tetrahydrophthalic anhydride, trialkyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylbutenyltetrahydrophthalic anhydride. 2 such as acid, anhydride of phthalic acid derivative, maleic anhydride, nadic anhydride, methyl nadic anhydride, glutaric anhydride, succinic anhydride, glycerin bistrimellitic anhydride monoacetate, and ethylene glycol bistrimellitic anhydride Functional acid anhydride curing agent, trifunctional acid anhydride curing agent such as trimellitic anhydride, pyromellitic anhydride, benzophenone tetracarboxylic acid anhydride, methylcyclohexene tetracarboxylic acid anhydride, and polyazeline acid anhydride Tetrafunctional or higher acid such as Things curing agents.

  From the viewpoint of further effectively reducing the gap between the members to be connected and from the viewpoint of further effectively improving the storage stability of the conductive material, the curing agent is preferably an acid anhydride curing agent.

  From the viewpoint of more effectively suppressing thermal degradation of the cured product, the acid anhydride curing agent is preferably a cyclic acid anhydride curing agent. Examples of the cyclic acid anhydride curing agent include trialkyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, and triacryltetrahydrophthalic anhydride.

  Examples of the thermal cationic curing agent include iodonium-based cationic curing agents, oxonium-based cationic curing agents, and sulfonium-based cationic 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.

  From the viewpoint of more effectively increasing the connection reliability of the connection target members connected by the conductive material, and from the viewpoint of further effectively increasing the storage stability of the conductive material, the curing agent is solid at 25 ° C. It is preferable.

  From the viewpoint of more efficiently arranging the solder particles on the electrode, the melting point of the curing agent is preferably lower than the melting point of the solder particles.

  The content of the curing agent is not particularly limited. In 100% by weight of the conductive material, the content of the curing agent is preferably 5% by weight or more, more preferably 10% by weight or more, preferably 50% by weight or less, more preferably 40% by weight or less. When the content of the curing agent is not less than the lower limit, it is easy to sufficiently cure the first curable compound and the second curable compound. When the content of the curing agent is not more than the above upper limit, it is difficult for an excess curing agent that did not participate in curing after curing to remain, and the heat resistance of the cured product is further increased.

  The content of the curing agent is preferably 10 parts by weight or more, more preferably 20 parts by weight or more, with respect to a total of 100 parts by weight of the first curable compound and the second curable compound. Preferably it is 200 weight part or less, More preferably, it is 150 weight part or less. When the content of the curing agent is not less than the lower limit, it is easy to sufficiently cure the first curable compound and the second curable compound. When the content of the curing agent is not more than the above upper limit, it is difficult for an excess curing agent that did not participate in curing after curing to remain, and the heat resistance of the cured product is further increased.

(Organic phosphorus compounds)
The conductive material according to the present invention may contain an organic phosphorus compound. As for the said organophosphorus compound, only 1 type may be used and 2 or more types may be used together.

  From the viewpoint of more efficiently arranging the solder particles on the electrode, the organic phosphorus compound is an organic phosphonium salt, an organic phosphoric acid, an organic phosphate ester, an organic phosphonic acid, an organic phosphonic acid ester, an organic phosphinic acid, or An organic phosphinic acid ester is preferred. From the viewpoint of more efficiently arranging the solder particles on the electrode, the organic phosphorus compound is more preferably an organic phosphonium salt.

  As said organic phosphonium salt, the organic phosphonium salt comprised by the phosphonium ion and its counter ion is mentioned. Examples of commercially available products of the above organic phosphonium salts include “Hishicolin” series manufactured by Nippon Chemical Industry Co., Ltd. As for the said organic phosphonium salt, only 1 type may be used and 2 or more types may be used together.

  The organic phosphoric acid, the organic phosphoric acid ester, the organic phosphonic acid, the organic phosphonic acid ester, the organic phosphinic acid, and the organic phosphinic acid ester are not particularly limited, and conventionally known compounds and commercially available products are used. Can do. Only 1 type may be used for these and 2 or more types may be used together.

  From the viewpoint of more efficiently arranging the solder particles on the electrode, the melting point of the organophosphorus compound is preferably 170 ° C. or less. From the viewpoint of more efficiently arranging the solder particles on the electrode, the organophosphorus compound is preferably liquid at 25 ° C.

  From the viewpoint of more efficiently arranging the solder particles on the electrode, the melting point of the organophosphorus compound is preferably lower than the melting point of the curing agent.

  The content of the organophosphorus compound with respect to 100 parts by weight of the curing agent is preferably 0.5 parts by weight or more, more preferably 0.8 parts by weight or more, preferably 10 parts by weight or less, more preferably 8 parts by weight or less. When the content of the organophosphorus compound is not less than the above lower limit and not more than the above upper limit, the solder particles can be more efficiently arranged on the electrode.

(flux)
The conductive material preferably contains a flux. By using the flux, the solder particles can be arranged more efficiently on the electrode. The flux is not particularly limited. As said flux, the flux generally used for soldering etc. 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 melting point (activation temperature) of the flux is preferably 10 ° C. or higher, more preferably 50 ° C. or higher, more preferably 70 ° C. or higher, still more preferably 80 ° C. or higher, preferably 200 ° C. or lower, more preferably 190 ° C. Hereinafter, it is more preferably 160 ° C. or lower, further preferably 150 ° C. or lower, and still more preferably 140 ° C. or lower. When the melting point 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 solder particles are more efficiently arranged on the electrode. The melting point (activation temperature) of the flux is preferably 80 ° C. or higher and 190 ° C. or lower. The melting point (activation temperature) 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.

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

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

  More preferably, the flux is a salt of an acid compound and a base compound. The acid compound preferably has an effect of washing the metal surface, and the base compound preferably has an action of neutralizing the acid compound. The flux is preferably a neutralization reaction product between the acid compound and the base compound. As for the said flux, only 1 type may be used and 2 or more types may be used together.

  From the viewpoint of more efficiently arranging the solder particles on the electrode, the melting point of the flux is preferably lower than the melting point of the solder particles, more preferably 5 ° C. or more, and more preferably 10 ° C. or less. Is more preferable. However, the melting point of the flux may be higher than the melting point of the solder particles. Usually, the use temperature of the conductive material is equal to or higher than the melting point of the solder particles, and if the melting point of the flux is equal to or lower than the use temperature of the conductive material, the melting point of the flux is higher than the melting point of the solder particles. The flux can sufficiently exhibit the performance as a flux. For example, in the conductive material in which the use temperature of the conductive material is 150 ° C. or higher, and includes solder particles (Sn42Bi58: melting point 139 ° C.) and a flux (melting point 146 ° C.) that is a salt of malic acid and benzylamine, the apple A flux that is a salt of an acid and benzylamine exhibits a sufficient flux effect.

  From the viewpoint of more efficiently arranging the solder particles on the electrode, the melting point of the flux is preferably lower than the reaction start temperature of the curing agent, more preferably 5 ° C or more, and more preferably 10 ° C or more. More preferably, it is low.

  The acid compound is preferably an organic compound having a carboxyl group. Examples of the acid compound include aliphatic carboxylic acids such as malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, citric acid, malic acid, and cyclic aliphatic carboxylic acid. Examples thereof include cyclohexyl carboxylic acid, 1,4-cyclohexyl dicarboxylic acid, aromatic carboxylic acid such as isophthalic acid, terephthalic acid, trimellitic acid, and ethylenediaminetetraacetic acid. The acid compound is preferably glutaric acid, azelaic acid, or malic acid.

  The base compound is preferably an organic compound having an amino group. Examples of the base compound include diethanolamine, triethanolamine, methyldiethanolamine, ethyldiethanolamine, cyclohexylamine, dicyclohexylamine, benzylamine, benzhydrylamine, 2-methylbenzylamine, 3-methylbenzylamine, 4-tert-butylbenzylamine. N-methylbenzylamine, N-ethylbenzylamine, N-phenylbenzylamine, N-tert-butylbenzylamine, N-isopropylbenzylamine, N, N-dimethylbenzylamine, imidazole compounds, and triazole compounds. . The base compound is preferably benzylamine, 2-methylbenzylamine, or 3-methylbenzylamine.

  The flux may be dispersed in the conductive material or may be attached on the surface of the solder particles. From the viewpoint of further effectively increasing the flux effect, the flux is preferably attached on the surface of the solder particles.

  From the viewpoint of further effectively increasing the storage stability of the conductive material, the flux is preferably solid at 25 ° C., and the flux is solid and dispersed in the conductive material at 25 ° C. preferable.

  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, more preferably 25% by weight or less. When the content of the flux is not less than the above lower limit and not more than the above upper limit, it is more difficult to form an oxide film on the surface of the solder and the electrode, and further, the oxide film formed on the surface of the solder and the electrode is further increased. Can be effectively removed.

(Filler)
The conductive material according to the present invention may contain a filler. The filler may be an organic filler or an inorganic filler. When the conductive material contains a filler, the solder particles can be uniformly aggregated on all the electrodes of the substrate.

  It is preferable that the conductive material does not contain the filler or contains the filler at 5% by weight or less. When the thermosetting compound is used, the smaller the filler content, the easier the solder particles move on the electrode.

  In 100% by weight of the conductive material, the content of the filler is preferably 0% by weight (not contained) or more, preferably 5% by weight or less, more preferably 2% by weight or less, and further preferably 1% by weight or less. It is. When the content of the filler is not less than the above lower limit and not more than the above upper limit, the solder particles are more efficiently arranged on the electrode.

(Other ingredients)
The conductive material may be, for example, a filler, an extender, a softener, a plasticizer, a thixotropic agent, a leveling agent, a polymerization catalyst, a curing catalyst, a colorant, an antioxidant, a heat stabilizer, and a light stabilizer. In addition, various additives such as ultraviolet absorbers, lubricants, antistatic agents and flame retardants may be contained.

(Connection structure and method of manufacturing connection structure)
The connection structure according to the present invention includes a first connection target member having a first electrode on the surface, a second connection target member having a second electrode on the surface, the first connection target member, A connecting portion connecting the second connection target member. In the connection structure according to the present invention, the material of the connection portion is 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 the first electrode on the surface, using the conductive material described above, and the conductive material. A second connection target member having a second electrode on the surface thereof opposite to the first connection target member side of the material so that the first electrode and the second electrode face each other. A connecting portion connecting the first connection target member and the second connection target member by heating the conductive material to a temperature equal to or higher than the melting point of the solder particles. And the step of electrically connecting the first electrode and the second electrode by a solder portion in the connection portion.

  In the connection structure and the manufacturing method of the connection structure according to the present invention, since the specific conductive material is used, the solder particles are likely to collect between the first electrode and the second electrode, Line). In addition, some of the solder particles are difficult to be disposed in a region (space) where no electrode is formed, and the amount of solder particles 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 dispose the solder efficiently on the electrode and to considerably reduce the amount of the solder disposed 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 70% or more, and preferably 100% or less.

  In the method for manufacturing a connection structure according to the present invention, in the step of arranging the second connection target member and the step of forming the connection portion, no pressure is applied, and the second connection is applied to the conductive material. The weight of the target member is preferably added, and in the step of arranging the second connection target member and the step of forming the connection portion, the conductive material exceeds the weight force of the second connection target member. It is preferable that no pressure is applied. In these cases, the uniformity of the amount of solder can be further enhanced in the plurality of solder portions. Furthermore, the thickness of the solder portion can be increased more effectively, and a plurality of solder particles can be easily collected between the electrodes, and the plurality of solder particles can be arranged more efficiently on the electrodes (lines). it can. Further, it is difficult for some of the plurality of solder particles to be arranged in a region (space) where no electrode is formed, and the amount of solder in the solder particles arranged in a region where no electrode is formed can be further reduced. it can. Therefore, the conduction reliability between the electrodes can be further enhanced. In addition, the electrical connection between the laterally adjacent electrodes that should not be connected can be further prevented, and the insulation reliability can be further improved.

  Moreover, if a conductive paste is used instead of a conductive film, it becomes easy to adjust the thickness of the connection part and the solder part depending on the amount of the conductive paste applied. On the other hand, in the conductive film, in order to change or adjust the thickness of the connection portion, it is necessary to prepare a conductive film having a different thickness or to prepare a conductive film having a predetermined thickness. There is. Moreover, in the conductive film, compared with the conductive paste, the melt viscosity of the conductive film cannot be sufficiently lowered at the melting temperature of the solder, and the aggregation of the solder particles tends to be hindered.

  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, the conductive material includes a first curable compound, a second curable compound, a curing agent, and solder particles. In the present embodiment, a conductive paste is used as the conductive material.

  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 compound 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. That is, by using the solder particles, the solder portion 4A, the first electrode 2a, and the solder portion are compared with the case where the conductive outer surface is made of a metal such as nickel, gold or copper. The contact area between 4A and the second electrode 3a increases. This also increases the conduction reliability and connection reliability in the connection structure 1. 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 particle separated from the solder part 4XA. In this embodiment, the amount of solder particles separated from the solder portion can be reduced, but the solder particles separated from the solder portion may be present 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, in the connection structures 1 and 1X, the first electrode 2a and the second electrode 2a are arranged in the stacking direction of the first electrode 2a, the connection portions 4 and 4X, and the second electrode 3a. When the portion facing the electrode 3a is viewed, the solder portion in the connection portions 4 and 4X is at least 50% of the area of 100% of the portion facing the first electrode 2a and the second electrode 3a. 4A and 4XA are preferably arranged.

  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) of the area of 100% of the portion 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.

  From the viewpoint of further improving the conduction reliability, the first electrode and the second electrode are opposed to each other in a direction orthogonal to the stacking direction of the first electrode, the connection portion, and the second electrode. When the matching portion is viewed, the portion where the first electrode and the second electrode face each other is 60% or more (more preferably 70% or more, more preferably 90%) of the solder portion in the connection portion. In particular, it is preferable that 95% or more, most preferably 99% or more) is 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 material 11 including a thermosetting component 11B and a plurality of solder particles 11A is disposed on the surface of the first connection target member 2 (first Process). The used conductive material 11 contains a thermosetting compound and a thermosetting agent as the thermosetting component 11B.

  The conductive material 11 is disposed on the surface of the first connection target member 2 on which the first electrode 2a is provided. After the conductive material 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 material 11 is not particularly limited, and examples thereof include application using a dispenser, screen printing, and ejection using an inkjet apparatus.

  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 material 11 on the surface of the first connection target member 2, on the surface opposite to the first connection target member 2 side of the conductive material 11, The 2nd connection object member 3 is arrange | positioned (2nd process). On the surface of the conductive material 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 material 11 is heated above the melting point of the solder particles 11A (third step). Preferably, the conductive material 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 more 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 that connects the first connection target member 2 and the second connection target member 3 is formed of the conductive material 11. The connection part 4 is formed of the conductive material 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 material 11. For this reason, the solder particles 11A are more effectively collected between the first electrode 2a and the second electrode 3a when the connection portion 4 is formed. In addition, if pressure is applied in at least one of the second step and the third step, the solder particles 11A tend to collect between the first electrode 2a and the second electrode 3a. The tendency to be inhibited becomes high.

  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 material is applied, the electrode of the first connection target member Even in a state where the alignment of the second connection target member with the electrode is deviated, the deviation can be corrected and the electrodes can be connected to each other (self-alignment effect). This is because the melted solder that is self-aggregating between the electrode of the first connection target member and the electrode of the second connection target member is connected to the electrode of the first connection target member and the second connection target member. Since it is more stable in terms of energy when the area where the solder between the electrode and other components of the conductive material is in contact is minimized, the force to make a connection structure with alignment, which is the connection structure with the smallest area Is to work. At this time, it is desirable that the conductive material is not cured and that the viscosity of components other than the solder particles of the conductive material is sufficiently low at that temperature and time.

  The viscosity of the conductive material at the melting point of the solder particles is preferably 50 Pa · s or less, more preferably 10 Pa · s or less, still more preferably 1 Pa · s or less, preferably 0.1 Pa · s or more, more preferably 0. .2 Pa · s or more. If the said viscosity is below the said upper limit, a solder particle can be aggregated efficiently. If the said viscosity is more than the said minimum, the void in a connection part can be suppressed and the protrusion of the electrically-conductive material other than a connection part can be suppressed.

  The viscosity of the conductive material at the melting point of the solder particles is as follows: STRESSTECH (manufactured by EOLOGICA), etc. When the melting point of the particles exceeds 200 ° C., the upper limit of the temperature is taken as the melting point of the solder particles). From the measurement results, the viscosity of the solder particles at the melting point (° C.) is evaluated.

  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 1st connection object member 2, the electrically-conductive material 11, and the 2nd connection object member 3 which are obtained is moved to a heating part, and the said 3rd connection object is carried out. 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 even more preferably 200 ° C. or lower.

  As the 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 particles and the curing temperature of the thermosetting compound, or a connection structure The method of heating only the connection part of a body locally is mentioned.

  As a tool used for the method of heating locally, a hot plate, a heat gun for applying hot air, a soldering iron, an infrared heater, and the like can be given.

  In addition, when heating locally with a hot plate, the metal directly under the connection is made of a metal with high thermal conductivity, and other places where heating is not preferred are made of a material with low thermal conductivity such as a fluororesin. The upper surface of the hot plate is preferably formed.

  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 particle 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, it is possible to efficiently collect the solder particles on the electrodes, thereby ensuring conduction reliability between the electrodes. The sex can be enhanced sufficiently. 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.

  In the connection structure according to the present invention, it is preferable that the first electrode and the second electrode are arranged in an area array or a peripheral. In the case where the first electrode and the second electrode are arranged in an area array or a peripheral, the effect of the present invention is more effectively exhibited. The area array is a structure in which electrodes are arranged in a grid pattern on the surface on which 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 may be aggregated along the direction perpendicular to the comb, whereas in the area array or peripheral structure, the entire surface on the surface where the electrodes are arranged In the conventional method, the amount of solder is likely to be non-uniform because the solder particles need to be uniformly agglomerated in the method of the present invention, whereas in the method of the present invention, the effects of the present invention are more effectively exhibited. The

  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.

Curing compound:
(1) Curable compound 1: Aliphatic epoxy compound, “Epolite 1600” manufactured by Kyoeisha Chemical Co., SP value: 9.8
(2) Curable compound 2: Aliphatic epoxy compound, “Epolite 100E” manufactured by Kyoeisha Chemical Co., SP value: 10.2.
(3) Curable compound 3: Aliphatic epoxy compound, “Epolite 40E” manufactured by Kyoeisha Chemical Co., SP value: 10.4
(4) Curing compound 4: Bisphenol A type epoxy compound, “YD-8125” manufactured by Nippon Steel & Sumikin Chemical Co., SP value: 10.5
(5) Curable compound 5: Bisphenol F type epoxy compound, “YDF-8170C” manufactured by Nippon Steel & Sumikin Chemical Co., SP value: 11
(6) Curable compound 6: Isocyanur skeleton-containing epoxy compound, “TEPIC-VL” manufactured by Nissan Chemical Industries, SP value: 12.9
(7) Curing compound 7: alicyclic epoxy compound, “Celoxide 2021P” manufactured by Daicel Corporation, SP value: 12

Curing agent:
(1) Curing agent 1: Acid anhydride curing agent, “Rikacid TH” manufactured by Shin Nippon Rika Co., Ltd., SP value: 12.4
(2) Curing agent 2: Acid anhydride curing agent, “Rikacid SA” manufactured by Shin Nippon Chemical Co., Ltd., SP value: 12.5
(3) Curing agent 3: Acid anhydride curing agent, “Pyromellitic acid anhydride” manufactured by Tokyo Chemical Industry Co., Ltd., SP value: 13.8
(4) Curing agent 4: Acid anhydride curing agent, “Rikacid TMTA-C” manufactured by Shin Nippon Rika Co., Ltd., SP value: 14
(5) Curing agent 5: Acid anhydride curing agent, “Ricacid TMEG” manufactured by Shin Nippon Chemical Co., Ltd., SP value: 14.7

Organophosphorus compounds:
(1) Organophosphorus compound 1: Organic phosphonium salt, “PX-4B” manufactured by Nippon Chemical Industry Co., Ltd.
(2) Organophosphorus compound 2: Organic phosphonium salt, “PX-4MP” manufactured by Nippon Chemical Industry Co., Ltd.
(3) Organophosphorus compound 3: Organic phosphonium salt, “PX-4ET” manufactured by Nippon Chemical Industry Co., Ltd.
(4) Organophosphorus compound 4: Organic phosphonium salt, “PX-4BT” manufactured by Nippon Chemical Industry Co., Ltd.

Solder particles:
Solder particles 1: SnBi solder particles, “Sn42Bi58” manufactured by Mitsui Kinzoku Kogyo Co., Ltd., d90: 4 μm
Solder particles 2: SnBi solder particles, “Sn42Bi58” manufactured by Mitsui Kinzoku Kogyo Co., Ltd., d90: 6 μm
Solder particles 3: SnBi solder particles, “Sn42Bi58” manufactured by Mitsui Kinzoku Kogyo Co., Ltd., d90: 10 μm
Solder particles 4: SnBi solder particles, “Sn42Bi58” manufactured by Mitsui Kinzoku Kogyo Co., Ltd., d90: 15 μm

SP values of curable compounds and curing agents:
The SP values of the curable compound and the curing agent were calculated by the Fedors estimation method.

D90 of solder particles:
The particle size distribution on the volume basis of the solder particles was measured with a laser diffraction particle size distribution measuring device (“Mastersizer 3000” manufactured by Malvern). From the result of the obtained particle size distribution, the d90 of the solder particles (the particle diameter of the solder particles when the cumulative volume of the solder particles is 90%) was determined.

(Examples 1-19 and Comparative Examples 1-3)
(1) Preparation of conductive material (anisotropic conductive paste) The components shown in the following Tables 1 and 2 are blended in the blending amounts shown in Tables 1 and 2 to obtain a conductive material (anisotropic conductive paste). It was.

(2-1) Specific manufacturing method of connection structure under condition A:
As a first connection target member, a copper electrode of 250 μm at a pitch of 400 μm is arranged in an area array on the surface of a semiconductor chip body (size 5 × 5 mm, thickness 0.4 mm), and a passivation film ( A semiconductor chip on which polyimide, a thickness of 5 μm, and an opening diameter of the electrode portion of 200 μm were formed was prepared. 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.

  A conductive material (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 a conductive material (anisotropic conductive paste) layer. Next, a semiconductor chip was laminated on the upper surface of the conductive material (anisotropic conductive paste) layer so that the electrodes face each other. The weight of the semiconductor chip is added to the conductive material (anisotropic conductive paste) layer. From this state, heating was performed so that the temperature of the conductive material (anisotropic conductive paste) layer reached 139 ° C. (melting point of solder) 5 seconds after the start of temperature increase. Further, after 15 seconds from the start of temperature increase, the conductive material (anisotropic conductive paste) layer is heated to a temperature of 160 ° C. to cure the conductive material (anisotropic conductive paste) layer. Obtained. No pressure was applied during heating.

(2-2) Specific manufacturing method of connection structure under condition B:
A connection structure (area array substrate) was produced in the same manner as in Condition A except that the following changes were made.

Changes from Condition A to Condition B:
After applying the conductive material (anisotropic conductive paste) immediately after fabrication to the upper surface of the glass epoxy substrate to a thickness of 100 μm to form a conductive material (anisotropic conductive paste) layer, It was left for 6 hours in a 50% humidity environment. After standing, a semiconductor chip was laminated on the upper surface of the conductive material (anisotropic conductive paste) layer so that the electrodes face each other.

(Evaluation)
(1) Presence / absence of blending of first curable compound and second curable compound In the obtained conductive material, from the SP value of the curable compound and the curing agent, the first curable compound and the second curable compound. It was confirmed whether or not a sex compound was contained. The presence or absence of blending of the first curable compound and the second curable compound was determined according to the following criteria.

[Judgment Criteria for Presence / Absence of Formulation of First Curing Compound]
A: The first curable compound is contained in the conductive material B: The first curable compound is not contained in the conductive material

[Criteria for the presence / absence of the second curable compound]
A1: The second curable compound is contained in the conductive material. A2: The second curable compound is not contained in the conductive material.

(2) Gap In the connection structure obtained under the conditions A and B, the height (gap) of the solder part in the connection part was measured with a scanning electron microscope. The gap was judged according to the following criteria.

[Gap criteria]
◯: Gap is less than 5 μm ○: Gap is 5 μm or more and less than 10 μm △: Gap is 10 μm or more and less than 15 μm ×: Gap is 15 μm or more

(3) Solder placement accuracy on the electrode In the connection structure obtained under the conditions A and B, the first electrode and the second electrode are arranged in the stacking direction of the first electrode, the connection portion, and the second electrode. When the portion facing the electrode is viewed, the ratio X of the area where the solder portion in the connecting portion is arranged in the area of 100% of the portion facing the first electrode and the second electrode is evaluated. 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 connection structure (n = 15) obtained in Condition A and Condition B, the connection resistance per connection point between the upper and lower electrodes is respectively determined by the four-terminal method. It was measured by. 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 50 mΩ or less ○: Average value of connection resistance exceeds 50 mΩ, 70 mΩ or less Δ: Average value of connection resistance exceeds 70 mΩ, 100 mΩ or less ×: Average value of connection resistance exceeds 100 mΩ Or there is a bad connection

(5) Insulation reliability between adjacent electrodes In the connection structure (n = 15) obtained in Condition A and Condition B, the electrodes are left in an atmosphere of 85 ° C. and 85% humidity for 100 hours, and then adjacent electrodes. In the meantime, 5V was applied 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) Gel fraction Among the components shown in Tables 1 and 2 below, components other than conductive particles were blended to obtain a curable composition. The obtained curable composition was heated at 160 ° C. for 1 hour while being pressurized at 1 MPa using a heating press machine to obtain a cured product having a thickness of 0.5 mm. 5 g of the obtained cured product was weighed and immersed in 100 g of toluene at 25 ° C. for 20 hours. Thereafter, the cured product was taken out and dried at 160 ° C. for 30 minutes, and the weight of the cured product after drying was measured. The gel fraction was calculated by the following formula. The gel fraction was determined according to the following criteria. In addition, the higher the gel fraction, the higher the gap retention due to the cured product portion of the connection structure.

  Gel fraction (%) = [weight of cured product after immersion in toluene (g) / weight of cured product before immersion in toluene (g)] × 100

[Criteria of gel fraction]
○○: Gel fraction is 90% or more and 100% or less ○: Gel fraction is 80% or more and less than 90% Δ: Gel fraction is 70% or more and less than 80% ×: Gel fraction is less than 70%

  The results are shown in Tables 1 and 2 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 material 11A ... Solder particles 11B ... Thermosetting component

Claims (13)

A conductive material comprising a first curable compound, a curing agent, and solder particles;
The conductive material does not include or includes a second curable compound;
The absolute value of the difference between the SP value of the first curable compound and the SP value of the curing agent is 2 or more;
The absolute value of the difference between the SP value of the second curable compound and the SP value of the curing agent is less than 2,
In a total of 100% by weight of the first curable compound and the second curable compound, the content of the first curable compound is 5% by weight or more,
The electrically conductive material whose d90 of the said solder particle is 10 micrometers or less in the particle size distribution on the volume basis of the said solder particle. Including the second curable compound;
The conductive material according to claim 1, wherein a content of the first curable compound is 90% by weight or less in a total of 100% by weight of the first curable compound and the second curable compound. .   The content of the second curable compound is 10% by weight or more in a total of 100% by weight of the first curable compound and the second curable compound, according to claim 1 or 2. Conductive material.   The conductive material according to claim 1, wherein an absolute value of a difference between an SP value of the first curable compound and an SP value of the curing agent is 5.5 or less.   The conductive material according to claim 1, wherein the curing agent is an acid anhydride curing agent.   The conductive material according to claim 1, wherein the first curable compound is an aliphatic compound.   The conductive material according to claim 1, wherein the first curable compound is an aliphatic epoxy compound.   The electrically conductive material of any one of Claims 1-7 containing an organic phosphorus compound.   The conductive material according to claim 1, which is a conductive paste. A first connection object member having a first electrode on its surface;
A second connection target member having a second electrode on its surface;
A connecting 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 the surface of the first connection target member having the first electrode on the surface;
On the surface opposite to the first connection target member side of the conductive material, the second connection target member having the second electrode on the surface is opposed to the first electrode and the second electrode. A step of arranging to
By heating the conductive material to a temperature equal to or higher than the melting point of the solder particles, a connection part connecting the first connection target member and the second connection target member is formed of the conductive material, and The manufacturing method of a connection structure provided with the process of electrically connecting a said 1st electrode and a said 2nd electrode with the solder part in the said connection part.   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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