JP2021028894A - Conductive material, connection structure and production method of connection structure - Google Patents

Abstract

To provide a conductive material capable of efficiently enhancing repair ability.SOLUTION: A conductive material of the invention comprises a thermal-setting component, a plurality of solder particles, and a gap material. A softening point of a cured object obtained by curing the thermo-setting component in a condition of a melting point+20°C of the solder particles and 3 minutes, is equal to or smaller than a melting point of the solder particles. When die share intensity at 25°C of a copper piece to the cured object obtained by curing the conductive material in a condition of a melting point+20°C of the solder particles and 3 minutes, is die share intensity DS25, and die share intensity at the melting point of the solder particles of the copper piece to the cured object obtained by curing the conductive material in a condition of the melting point+20°C of the solder particles and 3 minutes, is die share intensity DSmp, a ratio of the die share intensity DS25 with respect to the die share intensity DSmp is 10 or greater and 1000 or smaller.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 above conductive material and a method for manufacturing the connection structure.

In recent years, a connection method using a conductive material containing solder particles or the like has been used for connecting a substrate and an electronic component. Further, as the conductive material, an anisotropic conductive material may be used. In the anisotropic conductive material, conductive particles are dispersed in the binder resin.

The anisotropic conductive material is used to obtain various connection structures. Examples of the connection using the anisotropic conductive material include a connection between a flexible printed circuit board and a glass substrate (FOG (Film on Glass)), a connection between a semiconductor chip and a flexible printed circuit board (COF (Chip on Film)), and a semiconductor. Examples thereof include a connection between a chip and a glass substrate (COG (Chip on Glass)) and a connection between a flexible printed circuit board and a glass epoxy substrate (FOB (Film on Board)).

With the anisotropic conductive material, for example, when electrically connecting a glass epoxy substrate and an electronic component, an anisotropic conductive material containing conductive particles is arranged on the glass epoxy substrate. Next, the electronic components are laminated and heated and pressurized. As a result, the anisotropic conductive material is cured, and the electrodes are electrically connected to each other via the conductive particles to obtain a connection structure.

In the manufacture of connection structures, electronic components may not be connected properly, so it is possible to remove only the electronic components that were not properly connected and perform the work (repair) of trying to connect the electronic components again. is there. Therefore, the conductive material is required to have repairability (the property that only electronic components and the like that are not properly connected can be easily removed and the electronic components and the like can be connected again).

A connection structure (mounting structure) with improved repairability is disclosed in Patent Document 1 below. The following Patent Document 1 describes a semiconductor package including a plurality of first electrodes, a semiconductor package component having the plurality of first electrodes, a plurality of second electrodes, and a circuit board having the plurality of second electrodes. The mounting structure of the component is disclosed. In the mounting structure, an electrode bump is arranged on the first electrode, a joining member is arranged on the second electrode, and a resin member is arranged around the joining member. In the mounting structure, the electrode bump and the joining member are electrically connected, whereby the first electrode and the second electrode are electrically connected. In the mounting structure, the joining member and the resin member form a joining portion for joining the electrode bump and the second electrode. In the mounting structure, the wet-up height of the resin member arranged around the joint member satisfies (outer wet-up height) ≤ (inner wet-up height) × 0.8. Further, Patent Document 1 below discloses that the joint portion is a cured product obtained by curing a solder paste containing a solder material, a thermosetting resin, and a curing agent.

Japanese Unexamined Patent Publication No. 2018-181937

However, although the conventional conductive material has a certain degree of repairability, the repairability may not be sufficient. Further, in order to easily perform repair, a conductive material having further improved repairability is required.

An object of the present invention is to provide a conductive material capable of effectively enhancing repairability. 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 broad aspect of the present invention, it is a conductive material containing a thermocurable component, a plurality of solder particles, and a gap material, and the thermocurable component is applied under the conditions of the melting point of the solder particles + 20 ° C. and 3 minutes. The softening point of the cured product is equal to or lower than the melting point of the solder particles, and the die share of the copper piece at 25 ° C. with respect to the cured product obtained by curing the conductive material under the conditions of the melting point of the solder particles + 20 ° C. and 3 minutes. When the strength is the die shear strength DS25 and the die shear strength at the melting point of the solder particles of the copper piece with respect to the cured product obtained by curing the conductive material under the conditions of the melting point of the solder particles + 20 ° C. and 3 minutes is the die shear strength DSmp. Provided are conductive materials in which the ratio of the die shear strength DS25 to the die shear strength DSmp is 10 or more and 1000 or less.

In certain aspects of the conductive material according to the present invention, the thermosetting component comprises a thermosetting agent and the thermosetting agent comprises an acid anhydride curing agent.

In a specific aspect of the conductive material according to the present invention, the melting point of the solder particles is 120 ° C. or higher and 280 ° C. or lower.

In a specific aspect of the conductive material according to the present invention, the average particle size of the solder particles is 2 μm or more and 75 μm or less.

In a specific aspect of the conductive material according to the present invention, the content of the solder particles in 100% by weight of the conductive material is 45% by weight or more and 90% by weight or less.

In a specific aspect of the conductive material according to the present invention, the content of the gap material in 100% by weight of the conductive material is 0.01% by weight or more and 5% by weight or less.

In certain aspects of the conductive material according to the present invention, the conductive material is a conductive paste.

According to a broad 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, and the first connection target member. The connection portion is provided with a connection portion connecting the second connection target member, the material of the connection portion is the above-mentioned conductive material, and the first electrode and the second electrode are the connection portion. A connection structure is provided that is electrically connected by a solder portion inside.

According to a broad aspect of the present invention, the step of arranging the conductive material on the surface of the first connection target member having the first electrode on the surface and the said of the conductive material using the above-mentioned conductive material. A second connection target member having a second electrode on the surface is arranged on a surface opposite to the first connection target member side so that the first electrode and the second electrode face each other. By heating the conductive material above the melting point of the solder particles in the step, a connecting portion connecting the first connection target member and the second connection target member is formed by the conductive material. Further, there is provided a method for manufacturing a connection structure, which comprises a step of electrically connecting the first electrode and the second electrode by a solder portion in the connection portion.

The conductive material according to the present invention includes a thermosetting component, a plurality of solder particles, and a gap material. In the conductive material according to the present invention, the softening point of the cured product obtained by curing the thermosetting component under the conditions of the melting point of the solder particles + 20 ° C. and 3 minutes is equal to or lower than the melting point of the solder particles. The die shear strength of the copper piece at 25 ° C. with respect to the cured product obtained by curing the conductive material under the conditions of the melting point of the solder particles at + 20 ° C. and 3 minutes is defined as the die shear strength DS25. The die shear strength of the copper piece at the melting point of the solder particles with respect to the cured product obtained by curing the conductive material under the conditions of the melting point of the solder particles + 20 ° C. and 3 minutes is defined as the die shear strength DSmp. In the conductive material according to the present invention, the ratio of the die shear strength DS25 to the die shear strength DSmp is 10 or more and 1000 or less. Since the conductive material according to the present invention has the above-mentioned structure, the repairability can be effectively enhanced.

FIG. 1 is a cross-sectional view schematically showing a connection structure obtained by using the conductive material according to the embodiment of the present invention. 2 (a) to 2 (c) are cross-sectional views for explaining each step of an example of a method of manufacturing a connection structure using the conductive material according to the embodiment of the present invention. FIG. 3 is a cross-sectional view showing a modified example of the connection structure.

The details of the present invention will be described below.

(Conductive material)
The conductive material according to the present invention includes a thermosetting component, a plurality of solder particles, and a gap material. In the conductive material according to the present invention, the softening point of the cured product obtained by curing the thermosetting component under the conditions of the melting point of the solder particles (solder particles contained in the conductive material) + 20 ° C. and 3 minutes is the softening point of the solder particles. It is below the melting point. The die shear strength of the copper piece at 25 ° C. with respect to the cured product obtained by curing the conductive material under the conditions of the melting point of the solder particles (solder particles contained in the conductive material) + 20 ° C. and 3 minutes is defined as the die shear strength DS25. The die shear strength at the melting point of the solder particles of the copper piece with respect to the cured product obtained by curing the conductive material under the conditions of the melting point of the solder particles (solder particles contained in the conductive material) + 20 ° C. and 3 minutes is defined as the die shear strength DSmp. .. In the conductive material according to the present invention, the ratio of the die shear strength DS25 to the die shear strength DSmp is 10 or more and 1000 or less.

Since the conductive material according to the present invention has the above-mentioned structure, the repairability can be effectively enhanced.

Although the conventional conductive material has a certain degree of repairability, the repairability may not be sufficient. Further, in order to easily perform repair, a conductive material having further improved repairability is required.

The present inventors consider that the cause of the decrease in repairability of the conductive material is that the softening point of the cured product of the thermosetting component is high, the peeling of the cured product of the thermosetting component is not sufficient, and for each electronic component. It has been found that an error in coplanarity occurs and a difference in the amount of thermosetting components around the electrodes causes the cured products of the thermosetting components in adjacent electrodes to come into contact with each other. In the present invention, by setting the melting point of the solder particles and the softening point of the cured product of the thermosetting component in an appropriate range, the cured product can be sufficiently peeled off from the thermosetting component. Further, in the present invention, since the gap material is included, the coplanarity of each electronic component can be made constant, and the amount of the thermosetting component around the electrode can be made uniform, so that the thermosetting component in the adjacent electrode can be made uniform. It is possible to prevent the cured products of the above from coming into contact with each other. As a result, repairability can be effectively enhanced.

In the present invention, in order to obtain the above-mentioned effects, the use of a conductive material that satisfies a specific relationship greatly contributes.

Further, in the present invention, a plurality of solder particles are likely to collect between the upper and lower facing electrodes at the time of conductive connection between the electrodes, and the solder can be arranged on the electrodes (lines). Further, it is difficult for a part of the solder to be arranged between the lateral electrodes that should not be connected, and the amount of solder arranged between the lateral electrodes that should not be connected can be considerably reduced. As a result, in the present invention, the amount of residual solder can be reduced between the lateral electrodes that must not be connected.

Further, in the present invention, it is possible to prevent the displacement between the electrodes. In the present invention, when the second connection target member is superposed on the first connection target member on which the conductive material is arranged on the upper surface, the electrodes of the first connection target member and the electrodes of the second connection target member are aligned with each other. Even if the alignment is misaligned, the misalignment can be corrected and the electrodes can be connected to each other (self-alignment effect).

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

From the viewpoint of more efficiently arranging the solder on the electrodes, the viscosity (η25) of the conductive material at 25 ° C. is preferably 30 Pa · s or more, more preferably 50 Pa · s or more, and preferably 400 Pa · s or more. -S or less, more preferably 300 Pa · s or less. The viscosity (η25) can be appropriately adjusted depending on the type and amount of the compounding components.

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

The die shear strength of the copper piece at 25 ° C. with respect to the cured product obtained by curing the conductive material under the conditions of the melting point of the solder particles at + 20 ° C. and 3 minutes is defined as the die shear strength (DS25). The die shear strength at the melting point of the solder particles of the copper piece with respect to the cured product obtained by curing the conductive material under the conditions of the melting point of the solder particles + 20 ° C. and 3 minutes is defined as the die shear strength (DSmp). When the melting point of the solder particles contained in the conductive material is mp ° C, the cured product for measuring the die shear strength (DS25) and the die shear strength (DSmp) is heated at mp + 20 ° C. for 3 minutes as described above. Obtained by curing a conductive material. The die shear strength (DS25) is the die shear strength at 25 ° C. The die shear strength (DSmp) is the die shear strength at mp ° C.

In the conductive material according to the present invention, the ratio (DS25 / DSmp) of the die shear strength (DS25) at 25 ° C. to the die shear strength (DSmp) at the melting point of the solder particles is 10 or more and 1000 or less. The above ratio (DS25 / DSmp) is preferably 100 or more, more preferably 300 or more, preferably 700 or less, and more preferably 500 or less. When the ratio (DS25 / DSmp) is equal to or greater than the above lower limit and equal to or less than the above upper limit, the repairability can be further effectively enhanced.

The die shear strength (DS25) at 25 ° C. is preferably 100 N or more, more preferably 200 N or more, preferably 1000 N or less, and more preferably 700 N or less. When the die share strength (DS25) is equal to or higher than the lower limit and lower than the upper limit, the repairability can be further effectively enhanced.

The die shear strength (DSmp) at the melting point of the solder particles is preferably 0.1 N or more, more preferably 0.5 N or more, preferably 10 N or less, and more preferably 5 N or less. When the die shear strength (DSmp) is at least the above lower limit and at least the above upper limit, the repairability can be further effectively enhanced.

The die shear strength (DS25 and DSmp) can be measured as follows.

A conductive material is applied to the upper surface of a copper plate having a thickness of 500 μm in a range of 4 mm × 4 mm with a thickness of 50 μm to form a conductive material layer having a thickness of 50 μm. Next, a copper piece having a thickness of 500 μm and a size of 4 mm square is placed on the upper surface of the conductive material layer. After that, the solder is melted while heating so that the temperature of the conductive material layer is equal to or higher than the melting point of the solder (for example, the melting point of the solder + 20 ° C.), and the conductive material layer is made to have the melting point of the solder particles contained in the conductive material layer + 20 ° C. And cure for 3 minutes to obtain a test sample.

Using the obtained test sample, the die shear strength at 25 ° C. and the melting point of the solder particles is measured with a die shear tester (“DAGE 4000” manufactured by Arctech). Obtain the die shear strength of the copper piece with respect to the cured product of the conductive material.

The thermosetting start temperature of the thermosetting component is not particularly limited and may be equal to or lower than the melting point of the solder. Since the softening point of the thermosetting component is equal to or lower than the melting point of the solder, even if thermosetting is started below the melting point of the solder, the plurality of solder particles are opposed to each other by heating above the melting point of the solder. It can be easily gathered between the electrodes.

The thermosetting start temperature of the thermosetting component means the temperature at which the heat generation peak starts to rise in the DSC. Examples of the DSC device include "EXSTAR DSC7020" manufactured by SII.

The conductive material can be used as a conductive paste, a conductive film, or the like. 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 arranging the solder on the electrodes, 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.

(Solder particles)
The conductive material contains a plurality of solder particles. Both the central portion and the outer surface of the solder particles are formed of solder. The solder particles are particles in which both the central portion and the outer surface are solder. When conductive particles having a base particle formed of a material other than solder and a solder portion arranged on the surface of the base particle are used instead of the solder particles, the conductivity is formed on the electrode. It becomes difficult for particles to collect. Further, in the above-mentioned conductive particles, since the solder bondability between the conductive particles is low, the conductive particles that have moved on the electrodes tend to move easily to the outside of the electrodes, and the effect of suppressing the displacement between the electrodes is also obtained. Tends to be low.

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

The melting point of the solder particles is preferably 80 ° C. or higher, more preferably 100 ° C. or higher, preferably 300 ° C. or lower, and more preferably 160 ° C. or lower. When the melting point of the solder particles is equal to or higher than the lower limit and lower than the upper limit, the solder can be arranged more efficiently on the electrodes, and the insulation reliability and the conduction reliability can be further improved. it can.

The melting point of the solder particles can be determined by differential scanning calorimetry (DSC). Examples of the differential scanning calorimetry (DSC) device include "EXSTAR DSC7020" manufactured by SII.

Further, the solder particles preferably contain tin. The tin content in 100% by weight of the 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 tin content in the solder particles is at least the above lower limit, the connection reliability between the solder portion and the electrode becomes even higher.

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

By using the above solder particles, the solder melts and is bonded to the electrodes, and the solder portion conducts the electrodes. For example, the solder portion and the electrode are likely to come into surface contact rather than point contact, so that the connection resistance is low. Further, as a result of increasing the joint strength between the solder portion and the electrode by using the solder particles, peeling between the solder portion and the electrode is more difficult to occur, and the continuity reliability and the connection reliability are further improved.

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

The solder particles are preferably filler materials having a liquidus line of 450 ° C. or lower based on JIS Z3001: welding terminology. Examples of the composition of the solder particles include a metal composition containing zinc, gold, silver, lead, copper, tin, bismuth, indium and the like. A tin-indium type (117 ° C. eutectic) or a tin-bismuth type (139 ° C. eutectic), which has a low melting point and is lead-free, is preferable. That is, the solder particles preferably do not contain lead, and preferably contain tin and indium, or tin and bismuth.

In order to further increase the bonding strength between the solder part and the electrode, the solder particles are nickel, copper, antimony, aluminum, zinc, iron, gold, titanium, phosphorus, germanium, tellurium, cobalt, bismuth, manganese, chromium, etc. It may contain metals such as molybdenum and palladium. Further, 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 portion and the electrode, the content of these metals for increasing the bonding strength is preferably 0.0001% by weight or more, based on 100% by weight of the metal contained in the solder particles. It is preferably 1% by weight or less.

The average particle size of the solder particles is preferably 2 μm or more, more preferably 5 μm or more, preferably 60 μm or less, and more preferably 35 μm or less. The average particle size of the solder particles is preferably 20 μm or less, and more preferably 10 μm or less. When the average particle size of the solder particles is not less than the above lower limit and not more than the above upper limit, the solder can be arranged more efficiently on the electrodes, and the continuity reliability and the connection reliability are further improved. be able to. The average particle size of the solder particles is particularly preferably 2 μm or more and 10 μm or less. When the average particle size of the solder particles is 2 μm or more and 10 μm or less, the solder can be arranged more efficiently on the electrodes, and the conduction reliability and the connection reliability can be further improved. ..

The average particle size of the solder particles is more preferably a number average particle size. The average particle size of the solder particles can be determined by, for example, observing 50 arbitrary solder particles with an electron microscope or an optical microscope, calculating the average value of the particle size of each solder particle, or measuring the particle size distribution by laser diffraction. Required by doing. In observation with an electron microscope or an optical microscope, the particle size of each solder particle is determined as the particle size in a circle-equivalent diameter. In observation with an electron microscope or an optical microscope, the average particle diameter of any 50 solder particles in the circle equivalent diameter is substantially equal to the average particle diameter in the sphere equivalent diameter. In the laser diffraction type particle size distribution measurement, the particle size of each solder particle is obtained as the particle size in the equivalent sphere diameter. The average particle size of the solder particles is preferably calculated by laser diffraction type particle size distribution measurement.

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

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

CV value (%) = (ρ / Dn) × 100
ρ: Standard deviation of the particle size of the solder particles Dn: Mean value of the particle size of the solder particles

The shape of the solder particles is not particularly limited. The shape of the solder particles may be spherical, non-spherical, flat or the like.

The content of the solder particles in 100% by weight of the conductive material is preferably 45% by weight or more, more preferably 50% by weight or more, still more preferably 55% by weight or more, and particularly preferably 60% by weight or more. Is 85% by weight or less, more preferably 80% by weight or less, still more preferably 75% 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 can be arranged more efficiently on the electrodes, and it is easy to arrange a large amount of solder between the electrodes, and conduction is achieved. Reliability and insulation reliability can be enhanced even more effectively.

(Gap material)
The conductive material includes a gap material. The gap material is a gap material for securing a gap between two members at the time of conductive connection. The gap material comes into contact with the two members during conductive connection. At the time of conductive connection, the solder particles can be arranged in the space secured by the gap material so that one solder particle does not contact both of the two members. Further, in the present invention, by including the gap material, the coplanarity of each electronic component can be made constant, and the amount of the thermosetting component around the electrode can be made uniform, so that the thermosetting property in the adjacent electrode can be made uniform. It is possible to prevent the cured products of the components from coming into contact with each other. The shape of the gap material is preferably particles. The gap material is preferably gap particles. The melting point of the gap material may be 250 ° C. or higher, 300 ° C. or higher, 350 ° C. or higher, or 400 ° C. or higher. The melting point of the gap material may be 2000 ° C. or lower, or 1000 ° C. or lower.

The gap material is not particularly limited. Examples of the gap material include resin particles, inorganic particles other than metal particles, organic-inorganic hybrid particles, and metal particles. The gap material may be solder particles. The material of the solder particles as the gap material may be the material described above. When the gap material is the above-mentioned solder particles, it is preferable that the solder particles and the solder particles used as the gap material have different average particle diameters. When the gap material is the above-mentioned solder particles, the average particle size of the solder particles is preferably smaller than the average particle size of the solder particles used as the gap material. When the gap material is the above-mentioned solder particles, the solder particles preferably have a preferable configuration described in the above (solder particles) column, except for the average particle size.

When the gap material is solder particles, the melting point of the solder particles as the gap material is preferably equal to or higher than the melting point of the solder particles that are not the gap material from the viewpoint of effectively exhibiting the function as the gap material. ..

When the gap material is not solder particles, the melting point of the gap material is preferably equal to or higher than the melting point of the solder particles, preferably exceeds the melting point of the solder particles, and may exceed the melting point of the solder particles by 10 ° C. or higher. preferable.

From the viewpoint of arranging the solder on the electrodes more efficiently and controlling the distance between the members with higher accuracy, the gap material is preferably resin particles or metal particles. The gap material may be core-shell particles comprising a core and a shell disposed on the surface of the core. The core may be an organic core, and the shell may be an inorganic shell.

Various organic substances are preferably used as the material for the resin particles. Examples of the material of the resin particles include polyolefin resins such as polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyvinylidene chloride, polyisobutylene, and polybutadiene; acrylic resins such as polymethylmethacrylate and polymethylacrylate; polycarbonate, polyamide, and the like. Phenolic formaldehyde resin, melamine formaldehyde resin, benzoguanamine formaldehyde resin, urea formaldehyde resin, phenol resin, melamine resin, benzoguanamine resin, urea resin, epoxy resin, unsaturated polyester resin, saturated polyester resin, polyethylene terephthalate, polysulfone, polyphenylene oxide, polyacetal, Examples thereof include polyimide, polyamideimide, polyether ether ketone, polyether sulfone, divinylbenzene polymer, and divinylbenzene-based copolymer. Examples of the divinylbenzene-based copolymer and the like include a divinylbenzene-styrene copolymer and a divinylbenzene- (meth) acrylic acid ester copolymer. Since the hardness of the resin particles can be easily controlled within a suitable range, the material of the resin particles should be a polymer obtained by polymerizing one or more polymerizable monomers having an ethylenically unsaturated group. Is preferable.

When the resin particles are obtained by polymerizing a polymerizable monomer having an ethylenically unsaturated group, the polymerizable monomer having an ethylenically unsaturated group is a non-crosslinkable monomer. Examples thereof include crosslinkable monomers.

Examples of the non-crosslinkable monomer include styrene-based monomers such as styrene and α-methylstyrene; and carboxyl group-containing monomers such as (meth) acrylic acid, maleic acid, and maleic anhydride; Methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, cetyl (meth) acrylate, stearyl (meth) acrylate, Alkyl (meth) acrylate compounds such as cyclohexyl (meth) acrylate and isobornyl (meth) acrylate; 2-hydroxyethyl (meth) acrylate, glycerol (meth) acrylate, polyoxyethylene (meth) acrylate, and glycidyl (meth) acrylate. Oxylate atom-containing (meth) acrylate compounds such as; nitrile-containing monomers such as (meth) acrylonitrile; vinyl ether compounds such as methyl vinyl ether, ethyl vinyl ether, and propyl vinyl ether; vinyl acetate, vinyl butyrate, vinyl laurate, and stearic acid. Acid vinyl ester compounds such as vinyl; unsaturated hydrocarbons such as ethylene, propylene, isoprene, and butadiene; trifluoromethyl (meth) acrylate, pentafluoroethyl (meth) acrylate, vinyl chloride, vinyl fluoride, chlorostyrene, etc. Halogen-containing monomers and the like can be mentioned.

Examples of the crosslinkable monomer include tetramethylol methanetetra (meth) acrylate, tetramethylol methanetri (meth) acrylate, tetramethylol methanedi (meth) acrylate, trimethyl propanetri (meth) acrylate, and dipenta. Elythritol hexa (meth) acrylate, dipenta erythritol penta (meth) acrylate, glycerol tri (meth) acrylate, glycerol di (meth) acrylate, (poly) ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) Polyfunctional (meth) acrylate compounds such as acrylates, (poly) tetramethylene glycol di (meth) acrylates, and 1,4-butanediol di (meth) acrylates; triallyl (iso) cyanurate, triallyl trimellitate, divinylbenzene. , Dialyl phthalate, diallyl acrylamide, diallyl ether, and silane-containing monomers such as γ- (meth) acryloxypropyltrimethoxysilane, trimethoxysilylstyrene, and vinyltrimethoxysilane.

The term "(meth) acrylate" refers to acrylate and methacrylate. The term "(meth) acrylic" refers to acrylic and methacrylic. The term "(meth) acryloyl" refers to acryloyl and methacryloyl.

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

When the base material particles are inorganic particles other than metal or organic-inorganic hybrid particles, examples of the inorganic material for forming the base material particles include silica, alumina, barium titanate, zirconia, and carbon black. The inorganic substance is preferably not a metal. The particles formed of the silica are not particularly limited, but for example, after hydrolyzing a silicon compound having two or more hydrolyzable alkoxysilyl groups to form crosslinked polymer particles, firing is performed if necessary. Examples include particles obtained by doing so. Examples of the organic-inorganic hybrid particles include organic-inorganic hybrid particles formed of a crosslinked alkoxysilyl polymer and an acrylic resin.

The organic-inorganic hybrid particles are preferably core-shell type organic-inorganic hybrid particles having a core and a shell arranged on the surface of the core. It is preferable that the core is an organic core. It is preferable that the shell is an inorganic shell. From the viewpoint of effectively lowering the connection resistance between the electrodes, the base particle is preferably an organic-inorganic hybrid particle having an organic core and an inorganic shell arranged on the surface of the organic core.

Examples of the material for the organic core include the above-mentioned material for resin particles.

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

When the base material particles are metal particles, examples of the metal as the material of the metal particles include silver, copper, nickel, silicon, gold, tin and titanium. Further, the metal particles may be the solder particles described above.

The ratio of the average diameter of the gap material to the average particle size of the solder particles (average diameter of the gap material / average particle size of the solder particles) is preferably 1.5 or more, more preferably 2 or more, still more preferably 2. It is .5 or more, particularly preferably 3 or more, and most preferably 7 or more. The above ratio (average diameter of gap material / average particle diameter of solder particles) is preferably 30 or less, more preferably 17.5 or less. When the above ratio (average diameter of the gap material / average particle diameter of the solder particles) is equal to or higher than the lower limit and lower than the upper limit, the solder can be arranged more efficiently on the electrodes, and the distance between the members can be increased. It can be controlled with even higher precision.

The average diameter of the gap material is preferably 2 μm or more, more preferably 5 μm or more, further preferably more than 5 μm, particularly preferably 10 μm or more, preferably 100 μm or less, more preferably 80 μm or less, still more preferably 60 μm or less. , Especially preferably 35 μm or less. The average diameter of the gap material may exceed 10 μm or 20 μm. The average diameter of the gap material is preferably larger than the average particle diameter of the solder particles described above. When the average diameter of the gap material is not less than the above lower limit and not more than the above upper limit, the solder can be arranged more efficiently on the electrodes, and the continuity reliability and the connection reliability can be further improved. Can be done. The average diameter of the gap material is particularly preferably 10 μm or more and 35 μm or less. When the average diameter of the gap material is 10 μm or more and 35 μm or less, the solder can be arranged more efficiently on the electrodes, and the conduction reliability and the connection reliability can be further improved.

The average diameter of the gap material is more preferably a number average diameter. The average diameter of the gap material is obtained, for example, by observing 50 arbitrary gap materials with an electron microscope or an optical microscope and calculating the average value of the diameters of each gap material. The diameter of the gap material is preferably a dimension that maximizes the distance connecting two points on the outer circumference of the gap material with a straight line. When the gap material is a particle, the average diameter of the gap material is the average particle size. When the gap material is a particle, the particle size of the gap material per piece is determined as the particle size in a circle-equivalent diameter in observation with an electron microscope or an optical microscope. In observation with an electron microscope or an optical microscope, the average particle diameter of any 50 gap materials in the circle equivalent diameter is substantially equal to the average particle diameter in the sphere equivalent diameter. In the laser diffraction type particle size distribution measurement, the particle size of each gap material is obtained as the particle size at the equivalent diameter of a sphere. When the gap material is particles, the average particle size of the gap material is preferably calculated by laser diffraction type particle size distribution measurement.

The coefficient of variation (CV value) of the diameter of the gap material is preferably 5% or more, more preferably 10% or more, preferably 40% or less, and more preferably 30% or less. When the coefficient of variation of the particle size of the gap material is not less than the above lower limit and not more than the above upper limit, the solder can be arranged more efficiently on the electrode. However, the CV value of the particle size of the gap material may be less than 5%.

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

CV value (%) = (ρ / Dn) × 100
ρ: Standard deviation of the particle size of the gap material Dn: Mean value of the particle size of the gap material

The shape of the gap material is not particularly limited. The shape of the gap material may be spherical, non-spherical, flat or the like.

The content of the gap material in 100% by weight of the conductive material is preferably 0.1% by weight or more, more preferably 1% by weight or more, still more preferably 2% by weight or more, and preferably 20% by weight or less. More preferably, it is 10% by weight or less. When the content of the gap material is not less than the above lower limit and not more than the above upper limit, the solder can be arranged more efficiently on the electrodes, and it is easy to arrange a large amount of solder between the electrodes, and conduction is achieved. Reliability and insulation reliability can be enhanced even more effectively. When the content of the gap material is at least the above lower limit and at least the above upper limit, the spacing between the members can be controlled with even higher accuracy.

(Thermosetting component)
The conductive material contains a thermosetting component. The conductive material may contain a thermosetting compound and a thermosetting agent as thermosetting components. In order to cure the conductive material even more satisfactorily, the conductive material preferably contains a thermosetting compound and a thermosetting agent as thermosetting components. In order to cure the conductive material even more satisfactorily, the conductive material preferably contains a curing accelerator as a thermosetting component.

In the conductive material according to the present invention, the softening point of the cured product obtained by curing the thermosetting component under the conditions of the melting point of the solder particles + 20 ° C. and 3 minutes is equal to or lower than the melting point of the solder particles. The softening point of the cured product obtained by curing the thermosetting component under the conditions of the melting point of the solder particles + 20 ° C. and 3 minutes is preferably the melting point of the solder particles of −40 ° C. or higher, more preferably the melting point of the solder particles −. It is 20 ° C. or higher, preferably the melting point of the solder particles of −5 ° C. or lower, and more preferably the melting point of the solder particles of −10 ° C. or lower. When the softening point of the cured product is equal to or lower than the melting point of the solder particles, and is equal to or higher than the lower limit and lower than the upper limit, the cured product can be sufficiently peeled off from the thermosetting component, further improving the repair property. Can be enhanced.

The softening point of the cured product can be measured as follows.

The thermosetting component is cured under the conditions of melting point + 20 ° C. of the solder particles contained in the conductive material and 3 minutes to obtain a cured product. Using a dynamic viscoelasticity measuring device (“Rheogel-E” manufactured by UBM), the softening point of the obtained cured product was measured in a temperature range of 25 ° C. to the melting point of the solder particles contained in the conductive material and the rate of temperature rise 5 Measure at ° C / min and 10 Hz. From the obtained results, the softening point of the cured product is calculated.

(Thermosetting component: Thermosetting compound)
The thermosetting compound is not particularly limited. Examples of the thermosetting compound include oxetane compounds, epoxy compounds, episulfide compounds, (meth) acrylic compounds, phenol compounds, amino compounds, unsaturated polyester compounds, polyurethane compounds, silicone compounds and polyimide compounds. From the viewpoint of further improving the curability and viscosity of the conductive material, further effectively enhancing the conduction reliability, and further effectively enhancing the insulation reliability, the thermosetting compound is described as the above-mentioned thermosetting compound. Epoxy compounds or episulfide compounds are preferred, and epoxy compounds are more preferred. The thermosetting compound preferably contains an epoxy compound. Only one type of the thermosetting compound may be used, or two or more types may be used in combination.

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, and 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, adamantan skeleton epoxy compound, tricyclodecane skeleton epoxy compound, naphthylene ether type Examples thereof include epoxy compounds and epoxy compounds having a triazine nucleus as a skeleton. Only one type of the epoxy compound may be used, or two or more types may be used in combination.

The epoxy compound is liquid or solid at room temperature (23 ° C.), and when the epoxy compound is solid at room temperature, the melting temperature of the epoxy compound is preferably equal to or lower than the melting point of the solder. By using the above-mentioned preferable epoxy compound, the viscosity is high at the stage where the members to be connected are bonded, and when acceleration is applied due to an impact such as transportation, the first member to be connected and the second connection are connected. Positional deviation from the target member can be suppressed. Further, the heat at the time of curing can greatly reduce the viscosity of the conductive material, and the aggregation of the solder can be efficiently promoted.

The thermosetting compound preferably contains an epoxy compound from the viewpoint of further effectively enhancing the insulation reliability and further effectively enhancing the conduction reliability.

From the viewpoint of more efficiently arranging the solder on the electrodes, the thermosetting compound preferably contains a thermosetting compound having a polyether skeleton.

Examples of the thermosetting compound having a polyether skeleton include a compound having a glycidyl ether group at both ends of an alkyl chain having 3 to 12 carbon atoms, and a polyether skeleton having 2 to 4 carbon atoms. Examples thereof include a polyether type epoxy compound having a structural unit in which 2 to 10 are continuously bonded.

From the viewpoint of further effectively enhancing the heat resistance of the cured product, the thermosetting compound preferably contains a thermosetting compound having an isocyanuric skeleton.

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

The content of the thermosetting compound in 100% by weight of the conductive material is preferably 5% by weight or more, more preferably 10% by weight or more, still more preferably 15% by weight or more, and preferably 90% by weight or less. It is preferably 70% by weight or less, more preferably 50% by weight or less, and particularly preferably 30% by weight or less. When the content of the thermosetting compound is at least the above lower limit and at least the above upper limit, the solder can be arranged more efficiently on the electrodes, and the insulation reliability between the electrodes can be further effectively enhanced. , The conduction reliability between the electrodes can be further effectively improved. From the viewpoint of further effectively enhancing the impact resistance, it is preferable that the content of the thermosetting compound is large.

The content of the epoxy compound in 100% by weight of the conductive material is preferably 5% by weight or more, more preferably 10% by weight or more, still more preferably 15% by weight or more, preferably 90% by weight or less, more preferably 90% by weight or less. It is 70% by weight or less, more preferably 50% by weight or less, and particularly preferably 30% by weight or less. When the content of the epoxy compound is not less than the above lower limit and not more than the above upper limit, the solder can be arranged more efficiently on the electrodes, and the insulation reliability between the electrodes can be further effectively enhanced. The reliability of conduction between the solders can be further effectively increased. From the viewpoint of further enhancing the impact resistance, it is preferable that the content of the epoxy compound is large.

(Thermosetting component: Thermosetting agent)
The thermosetting agent is not particularly limited. The thermosetting agent heat-cures the thermosetting compound. Examples of the heat curing agent include thiol curing agents such as imidazole curing agents, amine curing agents, phenol curing agents, and polythiol curing agents, acid anhydride curing agents, thermal cation initiators (thermal cation curing agents), and thermal radical generators. Can be mentioned. From the viewpoint of further improving the repair property, the thermosetting agent is preferably an acid anhydride curing agent. Only one type of the thermosetting agent may be used, or two or more types may be used in combination.

From the viewpoint of enabling the conductive material to be cured more quickly at a low temperature, the thermosetting agent is preferably an imidazole curing agent, a thiol curing agent, or an amine curing agent. Further, from the viewpoint of enhancing the storage stability when the thermosetting compound and the thermosetting agent are mixed, the thermosetting agent is preferably a latent curing agent. The latent curing agent is preferably a latent imidazole curing agent, a latent thiol curing agent or a latent amine curing agent. The thermosetting agent may be coated with a polymer substance such as a polyurethane resin or a polyester resin.

The imidazole curing agent is not particularly limited. Examples of the imidazole curing agent include 2-methylimidazole, 2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-phenylimidazolium trimerite, and 2,4-diamino-6. -[2'-Methylimidazolyl- (1')] -ethyl-s-triazine and 2,4-diamino-6- [2'-methylimidazole- (1')]-ethyl-s-triazine isocyanuric acid adduct , 2-Phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2-phenyl-4-benzyl-5-hydroxymethylimidazole, 2-palatoryl-4-methyl-5 5-Position of 1H-imidazole in -hydroxymethylimidazole, 2-methitolyl-4-methyl-5-hydroxymethylimidazole, 2-metatruyl-4,5-dihydroxymethylimidazole, 2-palatoryl-4,5-dihydroxymethylimidazole, etc. Examples thereof include an imidazole compound in which the hydrogen in the above is substituted with a hydroxymethyl group and the hydrogen at the 2-position is replaced with a phenyl group or a toluyl group.

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

The amine curing agent is not particularly limited. Examples of the amine curing agent include hexamethylenediamine, octamethylenediamine, decamethylenediamine, 3,9-bis (3-aminopropyl) -2,4,8,10-tetraspiro [5.5] undecane and bis (4). -Aminocyclohexyl) methane, metaphenylenediamine, diaminodiphenylsulfone and the like.

The acid anhydride curing agent is not particularly limited, and any acid anhydride used as a curing agent for a thermosetting compound such as an epoxy compound can be widely used. Examples of the acid anhydride curing agent include phthalic anhydride, tetrahydrophthalic anhydride, trialkyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, and methylbutenyltetrahydrophthalic anhydride. Bifunctional such as phthalic acid derivative anhydride, maleic anhydride, nadic acid anhydride, methylnadic anhydride, glutaric anhydride, succinic anhydride, glycerinbis trimellitic anhydride monoacetate, and ethylene glycolbis trimellitic anhydride. Acid anhydride curing agent, trifunctional acid anhydride curing agent such as trimellitic anhydride, and pyromellitic anhydride, benzophenone tetracarboxylic acid anhydride, methylcyclohexenetetracarboxylic acid anhydride, polyazelineic acid anhydride, etc. Examples thereof include an acid anhydride curing agent having four or more functions.

The thermal cation initiator is not particularly limited. Examples of the thermal cation initiator include an iodonium-based cation curing agent, an oxonium-based cation curing agent, and a sulfonium-based cation curing agent. Examples of the iodonium-based cationic curing agent include bis (4-tert-butylphenyl) iodonium hexafluorophosphate and the like. 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. Examples of the thermal radical generator include azo compounds and organic peroxides. Examples of the azo compound include azobisisobutyronitrile (AIBN) and the like. Examples of the organic peroxide include di-tert-butyl peroxide and methyl ethyl ketone peroxide.

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

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

The content of the thermosetting agent is not particularly limited. With respect to 100 parts by weight of the thermosetting compound, the content of the thermosetting agent is preferably 0.01 parts by weight or more, more preferably 1 part by weight or more, preferably 200 parts by weight or less, more preferably. It is 100 parts by weight or less, more preferably 75 parts by weight or less. When the content of the thermosetting agent is at least the above lower limit, it is easy to sufficiently cure the conductive material. When the content of the thermosetting agent is not more than the above upper limit, it becomes difficult for excess thermosetting agent that was not involved in curing to remain after curing, and the heat resistance of the cured product is further increased.

(Thermosetting component: Curing accelerator)
The conductive material may contain a curing accelerator. The curing accelerator is not particularly limited. The curing accelerator preferably acts as a curing catalyst in the reaction between the thermosetting compound and the thermosetting agent. The curing accelerator preferably acts as a curing catalyst in the reaction with the thermosetting compound. Only one type of the curing accelerator may be used, or two or more types may be used in combination.

Examples of the curing accelerator include phosphonium salt, tertiary amine, tertiary amine salt, quaternary onium salt, tertiary phosphine, crown ether complex, and phosphonium ylide. Specifically, the curing accelerator includes an imidazole compound, an isocyanurate of an imidazole compound, dicyandiamide, a derivative of dicyandiamide, a melamine compound, a derivative of a melamine compound, diaminomaleonitrile, diethylenetriamine, triethylenetetramine, and tetraethylenepentamine. , Amine compounds such as bis (hexamethylene) triamine, triethanolamine, diaminodiphenylmethane, organic acid dihydrazide, 1,8-diazabicyclo [5,4,0] undecene-7, 3,9-bis (3-aminopropyl) Examples thereof include −2,4,8,10-tetraoxaspiro [5,5] undecane, boron trifluoride, and organic phosphorus compounds such as triphenylphosphine, tricyclohexylphosphine, tributylphosphine and methyldiphenylphosphine.

The phosphonium salt is not particularly limited. Examples of the phosphonium salt include tetranormal butyl phosphonium bromide, tetranormal butyl phosphonium O, O-diethyldithiophosphate, methyl tributyl phosphonium dimethyl phosphate, tetranormal butyl phosphonium benzotriazole, tetranormal butyl phosphonium tetrafluoroborate, and tetranormal. Butylphosphonium tetraphenylborate and the like can be mentioned.

The content of the curing accelerator is appropriately selected so that the thermosetting compound can be cured well. The content of the curing accelerator with respect to 100 parts by weight of the thermosetting compound 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. It is less than the weight part. When the content of the curing accelerator is not less than the above lower limit and not more than the above upper limit, the thermosetting compound can be cured satisfactorily.

(flux)
The conductive material may contain a flux. By using the flux, the solder can be placed more efficiently on the electrodes. The above flux is not particularly limited. As the flux, a flux generally used for solder bonding or the like can be used.

The flux includes 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, a hydrazine, an amine compound, an organic acid and the like. Examples include pine fat. Only one type of the above flux may be used, or two or more types may be used in combination.

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

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, carboxybenzoimidazole, benzotriazole, and carboxybenzotriazole.

The pine fat is a rosin containing abietic acid as a main component. Examples of the rosins include abietic acid and acrylic-modified rosins. The flux is preferably rosins, more preferably abietic acid. By using this preferable flux, the conduction reliability between the electrodes is further increased.

The active temperature (melting point) of the flux is 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. or lower, still more preferably 160 ° C. or higher. ° C. or lower, more preferably 150 ° C. or lower, even more preferably 140 ° C. or lower. When the active temperature of the flux is not less than the above lower limit and not more than the above upper limit, the flux effect is exhibited more effectively and the solder is arranged more efficiently on the electrode. The active temperature (melting point) of the flux is preferably 80 ° C. or higher and 190 ° C. or lower. The active temperature (melting point) of the flux is particularly preferably 80 ° C. or higher and 140 ° C. or lower.

The active temperature (melting point) of the flux is 80 ° C. or higher and 190 ° C. or lower. ℃), Dicarboxylic acids such as pimelic 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 may be dispersed in the conductive material or may be adhered to the surface of the solder particles.

The flux is preferably a flux that releases cations by heating. The use of a flux that releases cations upon heating allows the solder to be placed more efficiently on the electrodes.

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

From the viewpoint of arranging the solder on the electrodes more efficiently, enhancing the insulation reliability more effectively, and further enhancing the conduction reliability, the flux is an acid compound and a base compound. It is preferably a salt of.

The acid compound is preferably an organic compound having a carboxyl group. Examples of the acid compound include malonic acid, succinic acid, glutaric acid, adipic acid, pimelli acid, suberic acid, azelaic acid, sebacic acid, citric acid, malic acid, and cyclic aliphatic carboxylic acid, which are aliphatic carboxylic acids. Examples thereof include cyclohexylcarboxylic acid, 1,4-cyclohexyldicarboxylic acid, isophthalic acid which is an aromatic carboxylic acid, terephthalic acid, trimellitic acid, ethylenediaminetetraacetic acid and the like. From the viewpoint of arranging the solder on the electrodes more efficiently, enhancing the insulation reliability more effectively, and further enhancing the conduction reliability, the acid compounds are glutaric acid and cyclohexyl. It is preferably a carboxylic acid or an adipic acid.

The basic compound is preferably an organic compound having an amino group. Examples of the basic compound include diethanolamine, triethanolamine, methyldiethanolamine, ethyldiethanolamine, cyclohexylamine, dicyclohexylamine, benzylamine, benzhydrylamine, 2-methylbenzylamine, 3-methylbenzylamine, and 4-tert-butylbenzylamine. , N-Methylbenzylamine, N-ethylbenzylamine, N-phenylbenzylamine, N-tert-butylbenzylamine, N-isopropylbenzylamine, N, N-dimethylbenzylamine, imidazole compounds, and triazole compounds. .. From the viewpoint of arranging the solder on the electrodes more efficiently, enhancing the insulation reliability more effectively, and further enhancing the conduction reliability, the basic compound is benzylamine. Is 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, and more preferably 25% by weight or less. The conductive material does not have to contain flux. When the content of the flux is not less than the above lower limit and not more than the above upper limit, it becomes more difficult to form an oxide film on the surface of the solder and the electrode, and further, the oxide film formed on the surface of the solder and the electrode is further formed. 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 can be uniformly agglomerated on all the electrodes of the substrate.

The conductive material preferably does not contain the filler, or contains the filler in an amount of 5% by weight or less. When the thermosetting compound is used, the smaller the filler content, the easier it is for the solder to move onto the electrodes.

The content of the filler in 100% by weight of the conductive material is preferably 0% by weight (not contained) or more, preferably 5% by weight or less, more preferably 2% by weight or less, still more preferably 1% by weight or less. is there. When the content of the filler is not less than the above lower limit and not more than the above upper limit, the solder is more evenly arranged on the electrode.

(Other ingredients)
The conductive material may be, for example, a filler, a bulking agent, a softening agent, a plasticizer, a thixo agent, a leveling agent, a polymerization catalyst, a curing catalyst, a colorant, an antioxidant, a heat stabilizer, a light stabilizer, if necessary. , UV absorbers, lubricants, antistatic agents, flame retardants and other various additives may be included.

(Connecting structure and manufacturing method of connecting 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, and the first connection target member. It includes a connecting portion that connects to the second connection target member. In the connection structure according to the present invention, the material of the connection portion is the above-mentioned conductive material. 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 method for manufacturing a connection structure according to the present invention includes a step of arranging the conductive material on the surface of a first connection target member having a first electrode on the surface by using the above-mentioned conductive material. In the method for manufacturing a connection structure according to the present invention, a second connection target member having a second electrode on the surface opposite to the first connection target member side of the conductive material is provided on the surface of the conductive material. A step of arranging the electrode 1 and the second electrode so as to face each other is provided. The method for manufacturing a connection structure according to the present invention is a connection in which the first connection target member and the second connection target member are connected by heating the conductive material above the melting point of the solder particles. The portion is formed of the conductive material, and includes a step of electrically connecting the first electrode and the second electrode by a solder portion in the connecting portion.

In the connection structure and the method for manufacturing the connection structure according to the present invention, since a specific conductive material is used, the solder easily collects between the first electrode and the second electrode, and the solder is an electrode (line). Can be placed efficiently on top. Further, it is difficult for a part of the solder to be arranged in the region (space) where the electrode is not formed, and the amount of the solder arranged in the region where the electrode is not formed can be considerably reduced. Therefore, the conduction reliability between the first electrode and the second electrode can be improved. Moreover, it is possible to prevent electrical connection between electrodes adjacent in the lateral direction that should not be connected, and it is possible to improve insulation reliability.

Further, in order to efficiently arrange the solder on the electrodes and to considerably reduce the amount of the solder arranged in the region where the electrodes are not formed, the conductive material uses a conductive paste instead of a conductive film. Is preferable.

The thickness of the solder portion between the electrodes is preferably 10 μm or more, more preferably 20 μm or more, preferably 100 μm or less, and more preferably 80 μm or less. The solder wet area on the surface of the electrode (the area in contact with the solder in 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, no pressurization is performed in the step of arranging the second connection target member and the step of forming the connection portion, and the conductive material is connected to the second connection. It is preferable that the weight of the target member is added. 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, the conductive material is subjected to the weight force of the second connection target member. It is preferable that no pressurizing pressure exceeding the above is applied. In these cases, the uniformity of the amount of solder can be further improved in the plurality of solder portions. Further, the thickness of the solder portion can be increased more effectively, a large amount of solder can be easily collected between the electrodes, and the solder can be arranged more efficiently on the electrodes (lines). Further, it is difficult for a part of the solder to be arranged in the region (space) where the electrode is not formed, and the amount of the solder arranged in the region where the electrode is not formed can be further reduced. Therefore, the conduction reliability between the electrodes can be further improved. Moreover, it is possible to further prevent electrical connection between electrodes adjacent in the lateral direction that should not be connected, and it is possible to further improve insulation reliability.

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

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 by using the conductive material according to the embodiment of the present invention.

The connection structure 1 shown in FIG. 1 is a connection connecting the first connection target member 2, the second connection target member 3, the first connection target member 2, and the second connection target member 3. It includes a part 4. The connecting portion 4 is formed of the above-mentioned conductive material. In the present embodiment, the conductive material contains a thermosetting component, a plurality of solder particles, and a gap material 11C. In the present embodiment, the gap material 11C is a resin particle having an average particle diameter larger than that of the solder particles. The thermosetting component contains a thermosetting compound and a thermosetting agent. In this embodiment, a conductive paste is used as the conductive material.

The connecting portion 4 has a solder portion 4A in which a plurality of solder particles are gathered and bonded to each other, and a cured product portion 4B in which a thermosetting compound is thermoset.

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 connecting 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 a region different from the solder portion 4A (cured product portion 4B portion), there are no solder particles separated from the solder portion 4A. If the amount is small, the solder particles may be 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.

As shown in FIG. 1, in the connection structure 1, a plurality of solder particles are gathered between the first electrode 2a and the second electrode 3a, and after the plurality of solder particles are melted, a melt of the solder particles is formed. Soldered and spread on the surface of the electrode and then solidified to form the solder portion 4A. Therefore, the contact area between the solder portion 4A and the first electrode 2a and the contact area between the solder portion 4A and the second 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 a metal such as nickel, gold, or copper. The contact area between the 4A and the second electrode 3a becomes large. This also increases the continuity reliability and connection reliability of the connection structure 1. When the conductive material contains flux, the flux is generally gradually deactivated by heating.

In the connection structure 1 shown in FIG. 1, all of the solder portions 4A are located in facing regions between the first and second electrodes 2a and 3a. In the connection structure 1X of the modified example shown in FIG. 3, only the connection portion 4X is different from the connection structure 1 shown in FIG. The connection portion 4X has a solder portion 4XA and a cured product portion 4XB. Like the connection structure 1X, most of the solder portions 4XA are located in the opposite regions of the first and second electrodes 2a and 3a, and a part of the solder portions 4XA is the first and second electrodes. The electrodes 2a and 3a may protrude laterally from the facing regions. The solder portion 4XA protruding laterally from the facing regions of the first and second electrodes 2a and 3a is a part of the solder portion 4XA and is not a solder particle separated from the solder portion 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, it becomes easy to obtain the connection structure 1. If the amount of solder particles used is increased, it becomes easy to obtain the connection structure 1X.

In the connection structures 1 and 1X, when the portions facing each other of the first electrode 2a and the second electrode 3a are seen in the stacking direction of the first electrode 2a, the connection portions 4, 4X and the second electrode 3a. It is preferable that the solder portions 4A and 4XA in the connecting portions 4 and 4X are arranged in 50% or more of the area of 100% of the portions facing each other of the first electrode 2a and the second electrode 3a. .. When the solder portions 4A and 4XA in the connection portions 4 and 4X satisfy the above-mentioned preferable aspects, the continuity reliability can be further improved.

When the portion where the first electrode and the second electrode face each other is seen in the stacking direction of the first electrode, the connection portion, and the second electrode, the first electrode and the first electrode are seen. It is preferable that the solder portion in the connection portion is arranged in 50% or more of the area of 100% of the portions facing the electrodes of 2. When the portion where the first electrode and the second electrode face each other is seen in the stacking direction of the first electrode, the connection portion, and the second electrode, the first electrode and the first electrode are seen. It is more preferable that the solder portion in the connection portion is arranged in 60% or more of the area of 100% of the portions facing the electrodes of 2. When the portion where the first electrode and the second electrode face each other is seen in the stacking direction of the first electrode, the connection portion, and the second electrode, the first electrode and the first electrode are seen. It is more preferable that the solder portion in the connection portion is arranged in 70% or more of the area of 100% of the portions facing the electrodes of 2. When the portion where the first electrode and the second electrode face each other is seen in the stacking direction of the first electrode, the connection portion, and the second electrode, the first electrode and the first electrode are seen. It is particularly preferable that the solder portion in the connection portion is arranged in 80% or more of the area of 100% of the portions facing the electrodes of 2. When the portion where the first electrode and the second electrode face each other is seen in the stacking direction of the first electrode, the connection portion, and the second electrode, the first electrode and the first electrode are seen. It is most preferable that the solder portion in the connection portion is arranged in 90% or more of the area of 100% of the portions facing the electrodes of 2. When the solder portion in the connection portion satisfies the above-mentioned preferable embodiment, the continuity reliability can be further improved.

When the portions facing each other of the first electrode and the second electrode are viewed in a direction orthogonal to the stacking direction of the first electrode, the connection portion, and the second electrode, the first electrode is used. It is preferable that 60% or more of the solder portion in the connection portion is arranged at the portion where the electrode and the second electrode face each other. When the portions facing each other of the first electrode and the second electrode are viewed in a direction orthogonal to the stacking direction of the first electrode, the connection portion, and the second electrode, the first electrode is used. It is more preferable that 70% or more of the solder portion in the connection portion is arranged at the portion where the electrode and the second electrode face each other. When the portions facing each other of the first electrode and the second electrode are viewed in a direction orthogonal to the stacking direction of the first electrode, the connection portion, and the second electrode, the first electrode is used. It is more preferable that 90% or more of the solder portion in the connection portion is arranged at the portion where the electrode and the second electrode face each other. When the portions facing each other of the first electrode and the second electrode are viewed in a direction orthogonal to the stacking direction of the first electrode, the connection portion, and the second electrode, the first electrode is used. It is particularly preferable that 95% or more of the solder portion in the connection portion is arranged at the portion where the electrode and the second electrode face each other. When the portions facing each other of the first electrode and the second electrode are viewed in a direction orthogonal to the stacking direction of the first electrode, the connection portion, and the second electrode, the first electrode is used. It is most preferable that 99% or more of the solder portion in the connection portion is arranged at the portion where the electrode and the second electrode face each other. When the solder portion in the connection portion satisfies the above-mentioned preferable embodiment, the continuity reliability can be further improved.

Next, FIG. 2 describes an example of a method for manufacturing the connection structure 1 using the conductive material according to the embodiment of the present invention.

First, the first connection target member 2 having the first electrode 2a on the surface (upper surface) is prepared. Next, as shown in FIG. 2A, the conductive material 11 including the thermosetting component 11B, the solder particles 11A, and the gap material 11C is arranged on the surface of the first connection target member 2 ( First step, first placement step). The conductive material 11 used contains a thermosetting compound and a thermosetting agent as the thermosetting component 11B.

The conductive material 11 is arranged on the surface of the first connection target member 2 on which the first electrode 2a is provided. After the placement of the conductive material 11, the solder particles 11A and the gap material 11C are placed both on the first electrode 2a (line) and on the region (space) where the first electrode 2a is not formed. There is.

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

Further, a second connection target member 3 having the second electrode 3a on the front 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 of the conductive material 11 opposite to the first connection target member 2 side. The second connection target member 3 is arranged (second step, second arrangement step). The second connection target member 3 is arranged on the surface of the conductive material 11 from the second electrode 3a side. At this time, the first electrode 2a and the second electrode 3a are opposed to each other.

In the second arrangement step, the gap material 11C controls the distance between the first electrode 2a and the second electrode 3a. In the second arrangement step, the gap material 11C (per piece) is brought into contact with both the first electrode 2a and the second electrode 3a. The solder particles 11A are different from the gap material that controls the distance between the first electrode 2a and the second electrode 3a in the second arrangement step. In the second arrangement step, the solder particles 11A (per one) are not brought into contact with both the first electrode 2a and the second electrode 3a. By using the gap material, the distance between the first connection target member and the second connection target member can be controlled with high accuracy.

The distance between the first electrode and the second electrode in the second arrangement step is preferably 10 μm or more, more preferably 50 μm or more, preferably 500 μm or less, and more preferably 300 μm or less. When the distance between the first electrode and the second electrode in the second placement step is equal to or greater than the lower limit and equal to or lower than the upper limit, the solder can be arranged on the electrodes more efficiently. Conduction reliability and insulation reliability can be further improved.

Next, the conductive material 11 is heated above the melting point of the solder particles 11A (third step, connection 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 existing in the region where the electrodes are not formed gather between the first electrode 2a and the second electrode 3a (self-aggregation effect). When a 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. Further, the solder particles 11A are melted and joined to each other. Further, the thermosetting component 11B is thermoset. As a result, as shown in FIG. 2C, the connecting portion 4 connecting the first connecting target member 2 and the second connecting target member 3 is formed of the conductive material 11. The connecting portion 4 is formed by the conductive material 11, the solder portion 4A is formed by joining the plurality of solder particles 11A, and the cured product portion 4B is formed by thermosetting the thermosetting component 11B. If the solder particles 11A move sufficiently, the solder particles 11A that are not located between the first electrode 2a and the second electrode 3a start moving, and then the first electrode 2a and the second electrode It is not necessary to keep the temperature constant until the movement of the solder particles 11A to and from 3a is completed.

In the present embodiment, it is preferable not to pressurize 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. Therefore, when the connecting portion 4 is formed, the solder particles 11A are more effectively gathered between the first electrode 2a and the second electrode 3a. When pressurization is performed in at least one of the second step and the third step, the solder particles 11A tend to gather between the first electrode 2a and the second electrode 3a. Is more likely to be inhibited.

Further, in the present embodiment, since the pressurization is not performed, the first connection target member 2 and the second connection target member 3 are in a state where the first electrode 2a and the second electrode 3a are out of alignment. Even when and are overlapped with each other, the deviation can be corrected and the first electrode 2a and the second electrode 3a can be connected (self-alignment effect). This is because the molten solder that is self-aggregated between the first electrode 2a and the second electrode 3a is the solder between the first electrode 2a and the second electrode 3a and other conductive materials. This is because the energy is more stable when the area in contact with the components is the smallest, and the force for forming the aligned connection structure, which is the connection structure with the minimum area, works. At this time, it is desirable that the conductive material has a sufficiently low viscosity of components other than the solder particles of the conductive material at the temperature and time.

The viscosity (ηmp) of the conductive material at the melting point of the solder is preferably 50 Pa · s or less, more preferably 10 Pa · s or less, further preferably 1 Pa · s or less, preferably 0.1 Pa · s or more, more preferably. Is 0.2 Pa · s or more. When the viscosity (ηmp) is not more than the above upper limit, the solder can be efficiently aggregated on the electrode. When the viscosity (ηmp) is at least the above lower limit, voids at the connecting portion can be suppressed, and the protrusion of the conductive material to other than the connecting portion can be suppressed.

The viscosity (ηmp) is strain control 1 rad, frequency 1 Hz, temperature rise rate 20 ° C./min, measurement temperature range 25 ° C. to 200 ° C. (however, the melting point of the solder is 200 ° C.) using STRESSTECH (manufactured by REOLOGICA) or the like. If it exceeds, the upper limit of the temperature is set as the melting point of the solder). From the measurement results, the viscosity of the solder at the melting point is evaluated.

In this way, the connection structure 1 shown in FIG. 1 is obtained. The second step and the third step may be continuously performed. Further, after performing the second step, the obtained laminate of the first connection target member 2, the conductive material 11, and the second connection target member 3 is moved to the heating unit, and the third The process may be performed. In order to perform the heating, the laminate may be arranged on the heating member, or the laminate may be arranged in the 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, still more preferably 200 ° C. or lower.

As a heating method in the third step, a method of heating the entire connection structure using a reflow furnace or an oven or a connection structure above the melting point of the solder and the curing temperature of the thermosetting component or higher. A method of locally heating only the connection portion of the solder is mentioned.

Examples of the appliance used for the method of locally heating include a hot plate, a heat gun for applying hot air, a soldering iron, and an infrared heater.

When locally heating on a hot plate, use a metal with high thermal conductivity directly under the connection, and use a material with low thermal conductivity such as fluororesin in other places where heating is not preferable. , It is preferable to form the upper surface of the hot plate.

Further, the method for manufacturing a connecting structure according to the present invention may include a peeling step, a recoating step, and a reconnecting step. The above step is performed, for example, when the second connection target member is not properly connected.

The peeling step is a step of peeling the second connection target member from the first connection target member at the melting point of the solder particles. The method of peeling the second connection target member from the first connection target member is not particularly limited. As a method of peeling the second connection target member from the first connection target member, the second connection target member is separated from the first connection target member while heating the connection portion using a soldering iron or the like. A method of peeling from the solder is mentioned. Further, in the peeling step, a known peeling device or the like used for repair can be used.

Further, in the peeling step, after peeling the second connection target member from the first connection target member, the first connection target member may be washed with a solvent or the like, if necessary. ..

The recoating step is a step of recoating the conductive material on the first connection target member after the peeling step. The recoating step can be carried out under the same conditions as the first step.

In the reconnection step, the second connection target member is arranged on the conductive material after the recoating step, and the first connection target member and the second connection target member are reconnected. It is a process. The reconnection step can be carried out under the same conditions as the second step and the third step.

The first and second connection target members are not particularly limited. Specific examples of the first and second connection target members include electronic components such as semiconductor chips, semiconductor packages, LED chips, LED packages, capacitors and diodes, and resin films, printed circuit boards, flexible printed circuit boards, and flexible components. Examples thereof include electronic components such as flat cables, rigid flexible substrates, glass epoxy substrates, and circuit boards such as glass substrates. 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 circuit board, a flexible flat cable, or a rigid flexible substrate. It is preferable that the second connection target member is a resin film, a flexible printed circuit board, a flexible flat cable, or a rigid flexible substrate. Resin films, flexible printed circuit boards, flexible flat cables, and rigid flexible substrates have the properties of high flexibility and relatively light weight. When a conductive film is used for connecting the members to be connected, the solder tends to be difficult to collect on the electrodes. On the other hand, by using the conductive paste, even if a resin film, a flexible printed circuit board, a flexible flat cable or a rigid flexible substrate is used, the solder is efficiently collected on the electrodes, so that the conductivity between the electrodes is reliable. Can be sufficiently enhanced. When a resin film, a flexible printed circuit board, a flexible flat cable, or a rigid flexible substrate is used, the continuity reliability between the electrodes is improved by not applying pressure, as compared with the case where other members to be connected such as a semiconductor chip are used. The improvement effect can be obtained even more effectively.

Examples of the electrodes provided on the connection target member include metal electrodes such as gold electrodes, nickel electrodes, tin electrodes, aluminum electrodes, copper electrodes, molybdenum electrodes, silver electrodes, SUS electrodes, and tungsten electrodes. When the member to be connected is a flexible printed substrate, the electrodes are preferably gold electrodes, nickel electrodes, tin electrodes, silver electrodes or copper electrodes. When the connection target member is a glass substrate, the electrodes are preferably aluminum electrodes, copper electrodes, molybdenum electrodes, silver electrodes or tungsten electrodes. When the electrode is an aluminum electrode, it may be an electrode formed only of aluminum, or an electrode in which an aluminum layer is laminated on the surface of a metal oxide layer. Examples of the material of 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. When the first electrode and the second electrode are arranged in an area array or a peripheral, the solder can be uniformly aggregated on the entire surface. The area array is a structure in which the electrodes are arranged in a grid pattern on the surface on which the electrodes of the member to be connected are arranged. The peripheral is a structure in which electrodes are arranged on the outer peripheral portion of a member to be connected. In the case of a structure in which the electrodes are arranged in a comb shape, the solder may be aggregated along the direction perpendicular to the comb, whereas in the above area array or peripheral structure, the entire surface on the surface where the electrodes are arranged is covered. It is necessary for the solder to agglomerate uniformly. Therefore, in the conventional method, the amount of solder tends to be non-uniform, whereas in the method of the present invention, the solder can be uniformly agglomerated over the entire surface.

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

Thermosetting component (thermosetting compound):
Thermosetting compound 1: Aliphatic epoxy compound, "Epolite 1600" manufactured by Kyoeisha Chemical Co., Ltd.
Thermosetting compound 2: Phenolic novolac type epoxy compound, "DEN431" manufactured by DOWN
Thermosetting compound 3: Bisphenol F type epoxy compound, "YDF-8170C" manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.
Thermosetting compound 4: Bisphenol A type epoxy compound, "YD-8125" manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.
Thermosetting compound 5: Isocyanul skeleton-containing epoxy compound, Nissan Chemical Industries, Ltd. "TEPIC-SP" active hydrogen equivalent equivalent mixture

Thermosetting component (thermosetting agent):
Thermosetting agent 1: Acid anhydride curing agent, "Recasid TDA-100" manufactured by New Japan Chemical Co., Ltd.
Thermosetting agent 2: Acid anhydride curing agent, "Recasid MH" manufactured by New Japan Chemical Co., Ltd.
Thermosetting agent 3: Latent microencapsulated imidazole curing agent, "Novacure HX3941HP" manufactured by Asahi Kasei Chemicals Co., Ltd.

Thermosetting component (curing accelerator):
Curing accelerator 1: Organic phosphonium salt, "PX-4MP" manufactured by Nippon Chemical Industrial Co., Ltd.

flux:
Flux 1: "Benzylamine adipate salt", melting point 171 ° C
Method for producing flux 1:
In a glass bottle, 24 g of water as a reaction solvent and 13.89 g of adipic acid (manufactured by Wako Pure Chemical Industries, Ltd.) were put and dissolved at room temperature until uniform. Then, 10.715 g of benzylamine (manufactured by Wako Pure Chemical Industries, Ltd.) was added and stirred for about 5 minutes to obtain a mixed solution. The obtained mixture was placed in a refrigerator at 5 ° C. to 10 ° C. and left overnight. The precipitated crystals were separated by filtration, washed with water and vacuum dried to obtain flux 1.

Solder particles:
Solder particles 1: SnBi solder particles, melting point 138 ° C, solder particles selected from "Sn42Bi58" manufactured by Mitsui Kinzoku Co., Ltd., average particle size: 10 μm
Solder particles 2: SnAgCu solder particles, melting point: 217 ° C, "SnAg3Cu0.5" manufactured by Mitsui Mining & Smelting Co., Ltd., average particle size: 10 μm

Gap material:
Gap material 1: Divinylbenzene copolymer resin particles, "Micropearl SP-30" manufactured by Sekisui Chemical Co., Ltd., average particle size: 30 μm
Gap material 2: Divinylbenzene copolymer resin particles, "Gold Micropearl AU-30" manufactured by Sekisui Chemical Co., Ltd., average particle size: 30 μm

(Examples 1 to 12 and Comparative Examples 1 and 2)
(1) Preparation of Conductive Material (Anisotropic Conductive Paste) The components shown in Tables 1 and 2 below are blended in the blending amounts shown in Tables 1 and 2 below to obtain a conductive material (anisotropic conductive paste). It was.

(2) Preparation of Connection Structure As a second connection target member, a semiconductor chip in which 4 mm × 4 mm copper electrodes are arranged at a pitch of 500 μm is prepared on the surface of the semiconductor chip body (size 10 mm × 10 mm, thickness 1 mm). did.

As the first connection target member, copper is formed on the surface of the glass epoxy substrate body (size 20 mm × 20 mm, thickness 1 mm, material FR-4) so as to have the same pattern as the electrodes of the second connection target member. A glass epoxy substrate on which the electrodes are arranged was prepared.

On the upper surface of the glass epoxy substrate, a conductive material (anisotropic conductive paste) immediately after production is applied so as to have a thickness 1.5 times that of the gap material (Examples 1 to 12 and Comparative Example 2), or 50 μm (comparative). A conductive material (anisotropic conductive paste) layer was formed by coating as in Example 1) (first arrangement step). Next, a flexible printed circuit board was laminated on the upper surface of the conductive material (anisometric conductive paste) layer so that the electrodes face each other (second arrangement step). The weight of the flexible printed circuit board is added to the conductive material (anisotropic conductive paste) layer. From that state, the temperature of the conductive material (anisotropic conductive paste) layer was heated so as to reach the melting point of the solder 5 seconds after the start of temperature rise. Further, 15 seconds after the start of temperature rise, the conductive material (anisotropic conductive paste) layer is heated so as to reach the melting point of the solder to cure the conductive material (anisotropic conductive paste) layer, and the connection structure is formed. Obtained (connection process). No pressurization was performed during heating.

(Evaluation)
(1) Relationship between the softening point of the cured product and the melting point of the solder particles (the softening point of the cured product obtained by curing the thermosetting component under the conditions of the melting point of the solder particles contained in the conductive material + 20 ° C. and 3 minutes. Relationship with melting point of solder particles)
The thermosetting component used for producing the conductive material was prepared. The prepared thermosetting component was cured under the conditions of melting point + 20 ° C. and 3 minutes of the solder particles contained in the conductive material to obtain a cured product. Using a dynamic viscoelasticity measuring device (“Rheogel-E” manufactured by UBM), the softening point of the obtained cured product was measured in a temperature range of 25 ° C. to the melting point temperature of the solder particles contained in the conductive material and the rate of temperature rise. The measurement was carried out under the conditions of 5 ° C./min and 10 Hz. From the obtained results, the softening point of the cured product was calculated.

Solder particles used for producing the conductive material were prepared. The melting point of the prepared solder particles was calculated by differential scanning calorimetry (DSC). As the differential scanning calorimetry (DSC) device, "EXSTAR DSC7020" manufactured by SII was used.

From the obtained measurement results, it is determined whether or not the softening point of the cured product obtained by curing the thermosetting component under the conditions of the melting point of the solder particles contained in the conductive material + 20 ° C. and 3 minutes is equal to or lower than the melting point of the solder particles. confirmed. The relationship between the softening point of the cured product obtained by curing the thermosetting component under the conditions of the melting point of the solder particles contained in the conductive material at + 20 ° C. and 3 minutes and the melting point of the solder particles was determined by the following criteria.

[Criteria for determining the relationship between the softening point of the cured product obtained by curing the thermosetting component under the conditions of the melting point of the solder particles contained in the conductive material + 20 ° C. and 3 minutes, and the melting point of the solder particles]
◯: The melting point of the solder particles contained in the conductive material + 20 ° C. and the softening point of the cured product obtained by curing the thermosetting component under the conditions of 3 minutes are equal to or lower than the melting point of the solder particles ×: The solder particles contained in the conductive material The softening point of the cured product obtained by curing the thermosetting component under the conditions of melting point + 20 ° C. and 3 minutes exceeds the melting point of the solder particles.

(2) Die shear strength Using the obtained conductive material, the die shear strength (DS25) of the conductive material at 25 ° C. and the die shear strength (DSmp) at the melting point of the solder particles of the conductive material were calculated.

The die shear strengths (DS25 and DSmp) were measured as follows.

A conductive material was applied to the upper surface of a copper plate having a thickness of 500 μm in a range of 4 mm × 4 mm with a thickness of 50 μm to form a conductive material layer having a thickness of 50 μm. Next, a copper piece having a thickness of 500 μm and a size of 4 mm square was placed on the upper surface of the conductive material layer. Then, while heating so that the temperature of the conductive material layer becomes the melting point of the solder, the solder is melted, and the conductive material layer is cured at the melting point of the solder particles contained in the conductive material at + 20 ° C. for 3 minutes to prepare a test sample. Obtained. Using the obtained test sample, the die shear strength at 25 ° C. and the melting point of the solder particles was measured with a die shear tester (“DAGE 4000” manufactured by Arctech). The die shear strength of the copper piece with respect to the cured product of the conductive material was determined.

The conditions for measuring the die shear strength are as follows.
Equipment used age SERIES 4000
Load cell used DS100 (for 100 kg)
Test speed 300 μm / s
Descent speed 300 μm / s
Test height 30 μm

From the obtained measurement results, the ratio (DS25 / DSmp) of the die shear strength (DS25) at 25 ° C. to the die shear strength (DSmp) at the melting point of the solder particles was calculated. The die share strength was judged according to the following criteria.

[Die share strength criteria]
◯: Ratio (DS25 / DSmp) is 10 or more and 1000 or less ×: Ratio (DS25 / DSmp) is less than 10 or exceeds 1000

(3) Connection resistance In the obtained connection structure, the connection resistance between the upper and lower electrodes was measured by the 4-terminal method. The average value of the connection resistance was calculated. From the relationship of voltage = current x resistance, the connection resistance can be obtained by measuring the voltage when a constant current is passed. The connection resistance was judged according to the following criteria.

[Criteria for connection resistance]
○ ○: Average value of connection resistance is 8.0Ω or less ○: Average value of connection resistance is more than 8.0Ω and 10.0Ω or less △: Mean value of connection resistance is more than 10.0Ω and 15.0Ω or less × : Average value of connection resistance exceeds 15.0Ω

(4) Peelability The connection portion of the obtained connection structure was heated at the melting point of the solder particles, and the second connection target member was peeled from the first connection target member. After the peeling, it was visually observed whether or not the first member to be connected was peeled off, and whether or not the cured products of the thermosetting components in the adjacent electrodes were in contact with each other. The peelability was judged according to the following criteria.

[Criteria for peelability]
○○: The cured products of the thermosetting component are not in contact with each other, and no peeling is observed in the first connection target member. ○: The cured products of the thermosetting component are in contact with each other, but the first connection No peeling is observed on the target member ×: Peeling is observed on the first connection target member regardless of whether or not the cured products of the thermosetting component are in contact with each other.

(5) Reconnectivity The first connection target member after the evaluation of (4) detachability described above was prepared. Using the prepared first connection target member, the connection structure was produced again in the same manner as in "(2) Preparation of connection structure" described above. Further, the same evaluation as in (3) Connection resistance described above was performed using the reconnected connection structure. The reconnectivity was judged from the connection resistance of the reconnected connection structure according to the following criteria.

[Criteria for reconnectivity]
◯: The rate of increase of the connection resistance of the connection structure after reconnection is 10% or less with respect to the connection resistance of the connection structure before reconnection. ×: Reconnection with respect to the connection resistance of the connection structure before reconnection. The rate of increase in connection resistance of the connection structure after connection exceeds 10%

The results are shown in Tables 1 and 2 below.

1,1X ... Connection structure 2 ... First connection target member 2a ... First electrode 3 ... Second connection target member 3a ... Second electrode 4,4X ... Connection part 4A, 4XA ... Solder part 4B, 4XB ... Cured material 11 ... Conductive material 11A ... Solder particles 11B ... Thermosetting component 11C ... Gap material

Claims (9)

It is a conductive material containing a thermosetting component, a plurality of solder particles, and a gap material.
The softening point of the cured product obtained by curing the thermosetting component under the conditions of the melting point of the solder particles + 20 ° C. and 3 minutes is equal to or lower than the melting point of the solder particles.
The die shear strength of the copper piece at 25 ° C. with respect to the cured product obtained by curing the conductive material under the conditions of the melting point of the solder particles + 20 ° C. and 3 minutes is defined as the die shear strength DS25, and the conditions of the melting point of the solder particles + 20 ° C. and 3 minutes. When the die shear strength of the copper piece at the melting point of the solder particles with respect to the cured product obtained by curing the conductive material is the die shear strength DSmp, the ratio of the die shear strength DS25 to the die shear strength DSmp is 10 or more and 1000 or less. There is a conductive material. The thermosetting component contains a thermosetting agent and contains
The conductive material according to claim 1, wherein the thermosetting agent contains an acid anhydride curing agent. The conductive material according to claim 1 or 2, wherein the solder particles have a melting point of 120 ° C. or higher and 280 ° C. or lower. The conductive material according to any one of claims 1 to 3, wherein the average particle size of the solder particles is 2 μm or more and 75 μm or less. The conductive material according to any one of claims 1 to 4, wherein the content of the solder particles in 100% by weight of the conductive material is 45% by weight or more and 90% by weight or less. The conductive material according to any one of claims 1 to 5, wherein the content of the gap material is 0.01% by weight or more and 5% by weight or less in 100% by weight of the conductive material. The conductive material according to any one of claims 1 to 6, which is a conductive paste. A first connection target member having a first electrode on its surface,
A second connection target member having a second electrode on the surface,
A connecting portion connecting the first connection target member and the second connection target member is provided.
The material of the connecting portion is the conductive material according to any one of claims 1 to 7.
A connection structure in which the first electrode and the second electrode are electrically connected by a solder portion in the connection portion. A step of arranging the conductive material on the surface of a first connection target member having a first electrode on the surface using the conductive material according to any one of claims 1 to 7.
The first electrode and the second electrode face each other on a surface of the conductive material opposite to the first connection target member side, with the second connection target member having the second electrode on the surface. And the process of arranging
By heating the conductive material above the melting point of the solder particles, a connecting portion connecting the first connection target member and the second connection target member is formed by the conductive material, and A method for manufacturing a connection structure, comprising a step of electrically connecting the first electrode and the second electrode by a solder portion in the connection portion.

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