JP2019091693A - Conductive material, connection structure, and production method for connection structure - Google Patents

Abstract

To provide a conductive material capable of efficiently arranging a solder on an electrode, capable of efficiently enhancing insulation reliability between adjacent electrodes, and capable of efficiently enhancing conduction reliability between electrodes above and below to be connected.SOLUTION: A conductive material according to the present invention includes: a curable compound; a hardening accelerator; and solder particles, a particle size of the solder particles being 30 μm or smaller, when a melt viscosity of a composition excluding the solder particles in the conductive material is measured and a temperature showing a minimum value of the melt viscosity is set to X°C, the melt viscosity at X-10°C and the melt viscosity at X+10°C being 10 Pa . s or lower, respectively.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a conductive material comprising solder particles. The present invention also relates to a connection structure using the conductive material and a method of manufacturing the connection structure.

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

  The anisotropic conductive material is used to obtain various connection structures. As the connection by the anisotropic conductive material, for example, connection of a flexible printed substrate and a glass substrate (FOG (Film on Glass)), connection of a semiconductor chip and a flexible printed substrate (COF (Chip on Film)), semiconductor The connection between a chip and a glass substrate (COG (Chip on Glass)), the connection between a flexible printed substrate and a glass epoxy substrate (FOB (Film on Board)), and the like can be mentioned.

  For example, when electrically connecting an electrode of a flexible printed board and an electrode of a glass epoxy board with the above-mentioned anisotropic conductive material, an anisotropic conductive material containing conductive particles is arranged on the glass epoxy board Do. Next, the flexible printed circuit is laminated, and heated and pressurized. Thus, the anisotropic conductive material is cured to electrically connect the electrodes via the conductive particles to obtain a connection structure.

  Patent Document 1 below discloses a conductive material including a plurality of conductive particles having a solder and a thermosetting component on the outer surface portion of the conductive portion. In the conductive material, the minimum value of the viscosity of the conductive material at 25 ° C. or more and the melting point or less of the solder in the conductive particle is 25 Pa · s or more and 255 Pa · s or less. The average particle diameter of the conductive particles is 3 μm or more and 15 μm or less. In the conductive material, when the average particle diameter (μm) of the conductive particles is A and the viscosity (Pa · s) of the conductive material at the melting point of the solder in the conductive particles is B, the B is , (−5A + 100) or more and (−15A + 300) or less.

WO 2017/033931 A1

  In recent years, in conductive materials containing conductive particles having solder particles or solder on the surface, miniaturization and reduction in diameter of conductive particles having solder particles or solder on the surface are realized by fine pitching of wiring in a printed wiring board etc. Is in progress.

  When the solder particles and the like are simply reduced in particle diameter, there is a problem that solder particles and the like can not be efficiently arranged between the upper and lower electrodes to be connected at the time of conductive connection using a conductive material. In particular, when the conductive material is heated and cured, the viscosity of the conductive material may increase before the solder particles and the like sufficiently move on the electrode, and the solder particles and the like may remain in the region without the electrode. As a result, it may not be possible to sufficiently improve the conduction reliability between the electrodes to be connected and the insulation reliability between the adjacent electrodes that should not be connected.

  In addition, since the surface area of the solder particles and the like increases with the reduction of the particle diameter of the solder particles and the like, the total amount of oxides by the oxide film on the surface of the solder particles and the like also increases. If an oxide film is present on the surface of the solder particles etc., the solder particles etc. can not be efficiently aggregated on the electrode, so in the conventional conductive material, measures such as increasing the content of flux in the conductive material are taken. It will be necessary. However, when the content of the flux in the conductive material is increased, voids may occur in the cured product of the conductive material, or curing failure of the conductive material may occur. With conventional conductive materials, it is difficult to solve the above problems.

  The object of the present invention is to allow solder to be efficiently placed on the electrodes, to effectively enhance the insulation reliability between adjacent electrodes, and further to ensure conduction between the upper and lower electrodes to be connected. It is an object of the present invention to provide a conductive material capable of effectively enhancing the conductivity. Moreover, the objective of this invention is providing the manufacturing method of the connection structure which used the said electrically-conductive material, and a connection structure.

  According to a broad aspect of the present invention, it is a conductive material containing a thermosetting compound, a curing accelerator, and solder particles, and the particle diameter of the solder particles is 30 μm or less, and the solder particles in the conductive material The melt viscosity of the composition excluding the above is measured, and the melt viscosity at X-10 ° C. and the melt viscosity at X + 10 ° C. are each 10 Pa · s or less, when the temperature showing the minimum value of the melt viscosity is X ° C. A conductive material is provided.

  In a specific aspect of the conductive material according to the present invention, the temperature indicating the minimum value of the melt viscosity is 100 ° C. or more and 110 ° C. or less.

  In a specific aspect of the conductive material according to the present invention, the content of the curing accelerator relative to 100 parts by weight of the thermosetting compound is 0.1 parts by weight or more and 20 parts by weight 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 55% by weight or more and 75% by weight or less.

  In a specific aspect 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 And a connection portion connecting the second connection target member, the material of the connection portion is the above-described conductive material, and the first electrode and the second electrode are the connection portion. A connection structure is provided, which is electrically connected by the solder portion in the inside.

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

  According to a broad aspect of the present invention, a step of disposing the conductive material on the surface of the first connection target member having the first electrode on the surface using the above-mentioned conductive material, and the above-mentioned conductive material A second connection target member having a second electrode on the surface is disposed on the surface opposite to the first connection target member side such that the first electrode and the second electrode face each other. And forming a connection portion connecting the first connection target member and the second connection target member by the conductive material by heating the conductive material to a temperature higher than the melting point of the solder particles. And a step of electrically connecting the first electrode and the second electrode by a solder portion in the connection portion.

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

  The conductive material according to the present invention is a conductive material containing a thermosetting compound, a curing accelerator, and solder particles. In the conductive material according to the present invention, the particle diameter of the solder particles is 30 μm or less. In the conductive material according to the present invention, when the melt viscosity of the composition excluding the solder particles in the conductive material is measured, and the temperature indicating the minimum value of the melt viscosity is X ° C, the melt viscosity at X-10 ° C and The melt viscosity at X + 10 ° C. is 10 Pa · s or less, respectively. Since the conductive material according to the present invention has the above configuration, the solder can be efficiently disposed on the electrodes, and the insulation reliability between the adjacent electrodes can be effectively enhanced. The conduction reliability between the upper and lower electrodes to be connected can be effectively enhanced.

FIG. 1 is a cross-sectional view schematically showing a connection structure obtained by using a conductive material according to an embodiment of the present invention. FIGS. 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 a conductive material according to an embodiment of the present invention. FIG. 3 is a cross-sectional view showing a modified example of the connection structure.

  Hereinafter, the present invention will be described in detail.

(Conductive material)
The conductive material according to the present invention is a conductive material containing a thermosetting compound, a curing accelerator, and solder particles. In the conductive material according to the present invention, the particle diameter of the solder particles is 30 μm or less. The particle size of the solder particles is relatively small. In the conductive material according to the present invention, when the melt viscosity of the composition excluding the solder particles in the conductive material is measured, and the temperature indicating the minimum value of the melt viscosity is X ° C, the melt viscosity at X-10 ° C and The melt viscosity at X + 10 ° C. is 10 Pa · s or less, respectively. The composition excluding the solder particles in the conductive material is the conductive material excluding the solder particles, and contains all the components contained in the conductive material other than the solder particles in a compounding ratio in the conductive material. The composition excluding the above-mentioned solder particles in the above-mentioned conductive material mixes all the components contained in the above-mentioned conductive material other than solder particles in the compounding ratio in the conductive material, removes only the solder particles from the conductive material, It can be made.

  Since the conductive material according to the present invention has the above configuration, the solder can be efficiently disposed on the electrodes, and the insulation reliability between the adjacent electrodes can be effectively enhanced. The conduction reliability between the upper and lower electrodes to be connected can be effectively enhanced.

  In the case of a conductive material in which solder particles are simply reduced in particle size, when heat curing the conductive material, the viscosity of the conductive material tends to increase before the solder particles sufficiently move on the electrode. For this reason, solder particles may remain in the area where there are no electrodes, and the solder particles may not be efficiently arranged between the upper and lower electrodes to be connected. In addition, it may not be possible to sufficiently enhance the conduction reliability between the electrodes to be connected and the insulation reliability between the adjacent electrodes that should not be connected.

  The present inventors use solder particles having a specific particle diameter, and control the melt viscosity of the conductive material to a specific condition, so that the heat due to the temperature difference between the conductive material and the electrode at the time of conductive connection between the electrodes. It has been found that convection can occur and the solder particles can be moved efficiently and the solder can be efficiently placed on the electrodes. In the present invention, in spite of reducing the size of the solder particles, the movement of the solder particles on the electrodes sufficiently proceeds to efficiently arrange the solder between the electrodes to be connected. It is possible to enhance the conduction reliability and the insulation reliability.

  Also, when the electrode width or inter-electrode width is narrow, it tends to be difficult to gather the solder on the electrodes, but in the present invention, even if the electrode width or inter-electrode width is narrow, the solder is sufficiently brought close on the electrodes. It can be collected. According to the present invention, since the above configuration is provided, when the electrodes are electrically connected, the solder particles are easily collected between the upper and lower opposed electrodes, and the solder particles are efficiently placed on the electrodes (lines). Can be placed. Further, in the present invention, when the electrode width is wide, the solder particles are arranged more efficiently on the electrode.

  Also, in the present invention, by using solder particles having a specific particle diameter and controlling the melt viscosity of the conductive material to specific conditions, the solder particles can be efficiently aggregated on the electrode. There is no need to excessively increase the content of flux in the conductive material. As a result, the generation of voids in the cured product of the conductive material can be effectively suppressed, and the generation of curing defects of the conductive material can be effectively suppressed.

  In the present invention, in order to obtain the effects as described above, using solder particles having a specific particle diameter and controlling the melt viscosity of the conductive material under specific conditions greatly contributes.

  Further, according to the present invention, since the above configuration is provided, when the electrodes are electrically connected, the plurality of solder particles are easily collected between the upper and lower opposed electrodes, and the plurality of solder particles Line) can be placed uniformly. Further, some of the plurality of solder particles are difficult to be disposed in the region (space) in which the electrode is not formed, and the amount of solder particles disposed in the region in which the electrode is not formed can be considerably reduced. Therefore, the conduction reliability between the electrodes can be enhanced. Moreover, electrical connection between laterally adjacent electrodes, which should not be connected, can be prevented, and insulation reliability can be enhanced.

  Furthermore, in the present invention, positional deviation between the electrodes can be prevented. In the present invention, when the second connection target member is superimposed on the first connection target member on the upper surface of which the conductive material is disposed, the electrode of the first connection target member and the electrode of the second connection target member Even in the state where the alignment is deviated, it is possible to correct the deviation and connect the electrodes (self-alignment effect).

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

  The viscosity (η 25) at 25 ° C. of the conductive material is preferably 50 Pa · s or more, more preferably 100 Pa · s or more, and preferably 400 Pa · s, from the viewpoint of arranging the solder more uniformly on the electrode. s or less, more preferably 200 Pa · s or less. The viscosity (η 25) can be appropriately adjusted according to the type and the amount of the blending component.

  The viscosity (η 25) can be measured, for example, at 25 ° C. and 5 rpm using an E-type viscometer (“TVE 22L” manufactured by Toki Sangyo Co., Ltd.) or the like.

  The melt viscosity of the composition excluding the solder particles in the conductive material is measured, and the temperature showing the minimum value of the melt viscosity is taken as X ° C. The melt viscosity (η X -10) at X-10 ° C and the melt viscosity (η X + 10) at X + 10 ° C are each 10 Pa · s or less. The melt viscosity (ηX-10) and the melt viscosity (ηX + 10) are preferably 8 Pa · s or less, and more preferably 6 Pa · s or less. The lower limits of the melt viscosity (ηX-10) and the melt viscosity (ηX + 10) are not particularly limited. The melt viscosity (ηX-10) and the melt viscosity (ηX + 10) may each be 1 Pa · s or more. A solder can be arranged more efficiently on an electrode as the above-mentioned melt viscosity (eta X-10) and the above-mentioned melt viscosity (eta X +10) are more than the above-mentioned lower limit and below the above-mentioned upper limit, and insulation reliability is made much more. This can be effectively enhanced, and furthermore, the conduction reliability can be more effectively enhanced.

  The above melt viscosity (X X -10) and the above melt viscosity (η X + 10) are measured, for example, using a rheometer "HAAKE MARS III" manufactured by Thermo Fisher Scientific, frequency 2 Hz, heating rate 0.11 ° C / sec, measurement temperature It can be measured under the conditions of the range of 40 ° C to 200 ° C. In this measurement, the temperature showing the minimum value of the melt viscosity is taken as X ° C.

  The temperature (X ° C.) showing the minimum value of the melt viscosity is preferably 95 ° C. or more, more preferably 100 ° C. or more, still more preferably 103 ° C. or more, preferably 120 ° C. or less, more preferably 118 ° C. or less The temperature is more preferably 115 ° C. or less, particularly preferably 110 ° C. or less. The solder can be arranged more efficiently on the electrode when the temperature (X ° C.) at which the minimum value of the melt viscosity is at least the above lower limit and the above upper limit, and the insulation reliability is more effective. It is possible to enhance the conduction reliability more effectively.

  The said conductive material can be used as a conductive paste, a conductive film, etc. The conductive paste is preferably an anisotropic conductive paste, and the conductive film is preferably an anisotropic conductive film. From the viewpoint of arranging the solder more uniformly on the electrodes, the conductive material is preferably a conductive paste. The said conductive material is used suitably for the electrical connection of an electrode. The conductive material is preferably a circuit connection material.

  Hereinafter, each component contained in a conductive material is demonstrated. In the present specification, "(meth) acrylic" means one or both of "acrylic" and "methacrylic".

(Solder particles)
Both the central portion and the outer surface of the solder particles are formed by solder. The solder particles are particles in which both the central portion and the outer surface are solder. In the case of using conductive particles comprising a base material particle formed of a material other than solder and a solder portion disposed on the surface of the base material particle instead of the above-mentioned solder particles, conductivity is achieved on the electrode It becomes difficult for particles to collect. In addition, in the conductive particles described above, since the solderability of the conductive particles is low, the conductive particles moved onto the electrodes tend to move out of the electrodes, and the effect of suppressing displacement between the electrodes is also obtained. It tends to be lower.

  It is preferable that the said solder is a metal (low melting metal) whose melting | fusing point is 450 degrees C or less. It is preferable that the said solder particle is a metal particle (low melting-point metal particle) whose melting | fusing point is 450 degrees C or less. The low melting point metal particles are particles containing a low melting point metal. The low melting point metal means a metal having a melting point of 450 ° C. or less. The melting point of the low melting point metal is preferably 300 ° C. or less, more preferably 160 ° C. or less. The solder particles are preferably low melting point solder having a melting point of less than 150.degree.

  The melting point of the solder particles can be determined by differential scanning calorimetry (DSC). Examples of a differential scanning calorimetry (DSC) apparatus include "EXSTAR DSC 7020" manufactured by SII.

  Preferably, the solder particles contain tin. The content of tin is preferably 30% by weight or more, more preferably 40% by weight or more, still more preferably 70% by weight or more, particularly preferably 90% by weight or more, in 100% by weight of the metal contained in the solder particles. . The connection reliability of a solder part and an electrode becomes it still higher that content of tin in the said solder particle is more than the said minimum.

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

  By using the above-described solder particles, the solder melts and joins to the electrodes, and the solder portions conduct between the electrodes. For example, since the solder portion and the electrode are likely to be in surface contact rather than point contact, connection resistance is reduced. Moreover, as a result of the use of the above-mentioned solder particles, the joint strength between the solder portion and the electrode becomes high, so that peeling between the solder portion and the electrode becomes even more difficult to occur, and the conduction reliability and the connection reliability become even higher.

  The metal which comprises the said solder particle is not specifically 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, a tin-silver alloy, a tin-silver-copper alloy, a tin-bismuth alloy, or a tin-indium alloy because the wettability to the electrode is excellent. More preferably, tin-bismuth alloy or tin-indium alloy is used.

  It is preferable that the said solder particle is a filler material whose liquidus line is 450 degrees C or less based on JISZ3001: welding term. Examples of the composition of the solder particles include metal compositions containing zinc, gold, silver, lead, copper, tin, bismuth, indium and the like. Low melting point and lead-free tin-indium (117 ° C eutectic) or tin-bismuth (139 ° C eutectic) is preferable. That is, the solder particles preferably do not contain lead, and preferably contain tin and indium, or contain tin and bismuth.

  The above-mentioned solder particles are nickel, copper, antimony, aluminum, zinc, iron, gold, titanium, phosphorus, germanium, tellurium, cobalt, bismuth, manganese, chromium, in order to further increase the joint strength between the solder portion and the electrode. You 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 enhancing the bonding strength between the solder portion and the electrode, the content of these metals for enhancing the bonding strength is preferably 0.0001% by weight or more, preferably 1% by weight in 100% by weight of the solder particles. % Or less.

  The particle diameter of the said solder particle is 30 micrometers or less. The particle diameter of the solder particles is preferably 1 μm or more, more preferably 2 μm or more, still more preferably 3 μm or more, preferably 25 μm or less, more preferably 20 μm or less, still more preferably 10 μm or less. The solder can be arranged more efficiently on the electrode as the particle diameter of the solder particles is equal to or more than the lower limit and equal to or less than the upper limit. The particle diameter of the solder particles is particularly preferably 3 μm to 10 μm. When the particle diameter of the solder particle satisfies the above-mentioned preferable embodiment, the solder can be arranged more efficiently on the electrode, and the insulation reliability can be more effectively enhanced.

  The particle diameter of the solder particles is preferably an average particle diameter, and more preferably a number average particle diameter. As for the particle diameter of the solder particles, for example, 50 arbitrary solder particles are observed with an electron microscope or an optical microscope to calculate the average value of the particle diameter of each solder particle, or to perform laser diffraction particle size distribution measurement. Determined by In the observation with an electron microscope or an optical microscope, the particle diameter of each solder particle is determined as the particle diameter at the equivalent circle diameter. In observation with an electron microscope or an optical microscope, the average particle diameter at the equivalent circle diameter of any 50 solder particles is approximately equal to the average particle diameter at the equivalent sphere diameter. In the laser diffraction type particle size distribution measurement, the particle diameter of each solder particle is determined as the particle diameter at a sphere equivalent diameter. The average particle size of the solder particles is preferably calculated by laser diffraction particle size distribution measurement.

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

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

  The content of the solder particles is preferably 55 wt% or more, more preferably 62 wt% or more, and preferably 75 wt% or less, more preferably 70 wt% or less in 100 wt% of the conductive material. It is easy to arrange solder more efficiently on an electrode as content of the above-mentioned solder particle is more than the above-mentioned lower limit and below the above-mentioned upper limit, and conduction reliability becomes still higher effectively. From the viewpoint of more effectively enhancing the conduction reliability, it is preferable that the content of the solder particles is large.

  The said conductive material contains a thermosetting compound and a hardening accelerator as a thermosetting component. In order to increase the degree of curing of the conductive material, the conductive material preferably contains a thermosetting agent as a thermosetting component.

  Hereinafter, each component contained in a conductive material is demonstrated.

(Thermosetting compound)
The said thermosetting compound is not specifically 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, the viewpoint of enhancing the conduction reliability more effectively, and the viewpoint of enhancing the insulation reliability more effectively, an epoxy compound or an episulfide compound is preferable, Epoxy compounds are more preferred. It is preferable that the said thermosetting compound 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 compounds include bisphenol A type epoxy compounds, bisphenol F type epoxy compounds, bisphenol S type epoxy compounds, phenol novolac type epoxy compounds, biphenyl type epoxy compounds, biphenyl novolac type epoxy compounds, biphenol type epoxy compounds, naphthalene type epoxy compounds , Fluorene type epoxy compounds, phenol aralkyl type epoxy compounds, naphthol aralkyl type epoxy compounds, dicyclopentadiene type epoxy compounds, anthracene type epoxy compounds, epoxy compounds having an adamantane skeleton, epoxy compounds having a tricyclodecane skeleton, naphthalene ether type The epoxy compound, the epoxy compound which has a triazine nucleus in frame | skeleton, etc. are mentioned. Only one type of the epoxy compound may be used, or two or more types may be used in combination.

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

  From the viewpoint of more effectively improving the insulation reliability and the viewpoint of more effectively improving the conduction reliability, the above-mentioned thermosetting compound preferably contains an epoxy compound.

  From the viewpoint of more effectively improving 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 isocyanuric skeleton include triisocyanurate type epoxy compounds and the like, and TEPIC series (TEPIC-G, TEPIC-S, TEPIC-SS, TEPIC-HP, TEPIC-L, manufactured by Nissan Chemical Industries, Ltd.). TEPIC-PAS, TEPIC-VL, TEPIC-UC) etc. are mentioned.

  The content of the thermosetting compound is preferably 20% by weight or more, more preferably 40% by weight or more, still more preferably 50% by weight or more, and preferably 99% by weight or less in 100% by weight of the conductive material. It is preferably at most 98 wt%, more preferably at most 90 wt%, particularly preferably at most 80 wt%. When the content of the thermosetting compound is not less than the lower limit and not more than the upper limit, the solder can be arranged more efficiently on the electrodes, and the insulation reliability between the electrodes can be more effectively enhanced. The conduction reliability between the electrodes can be more effectively enhanced. From the viewpoint of more effectively improving the impact resistance, the content of the thermosetting compound is preferably as large as possible.

  The content of the above-mentioned epoxy compound is preferably 20% by weight or more, more preferably 40% by weight or more, still more preferably 50% by weight or more, and preferably 99% by weight or less, more preferably 100% by weight of the conductive material. It is at most 98 wt%, more preferably at most 90 wt%, particularly preferably at most 80 wt%. When the content of the epoxy compound is at least the lower limit and the upper limit, the solder can be arranged more efficiently on the electrodes, and the insulation reliability between the electrodes can be more effectively enhanced. Conduction reliability can be more effectively enhanced. From the viewpoint of further improving the impact resistance, the content of the epoxy compound is preferably as large as possible.

(Heat curing agent)
The conductive material preferably contains a thermosetting agent. The said thermosetting agent is not specifically limited. The thermosetting agent thermally cures the thermosetting compound. Examples of the thermosetting agent include imidazole curing agents, amine curing agents, phenol curing agents, thiol curing agents such as polythiol curing agents, acid anhydride curing agents, thermal cation initiators (thermal cationic curing agents), thermal radical generating agents, etc. Can be mentioned. 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 rapidly at low temperature, the heat curing 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 polymeric 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 trimellitate, 2,4-diamino-6 -[2'-Methylimidazolyl- (1 ')]-ethyl-s-triazine and 2,4-diamino-6- [2'-methylimidazolyl- (1')]-ethyl-s-triazine isocyanuric acid adduct , 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2-phenyl-4-benzyl-5-hydroxymethylimidazole, 2-paratoluyl-4-methyl-5 -Hydroxymethylimidazole, 2-metatoluyl-4-methyl-5-h The hydrogen at the 5-position of 1H-imidazole in hydroxymethylimidazole, 2-metatoluyl-4,5-dihydroxymethylimidazole, 2-paratoluyl-4,5-dihydroxymethylimidazole, etc. is a hydroxymethyl group at the 2-position The imidazole compound etc. which were substituted by the phenyl group or toluyl group are mentioned.

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

  The above-mentioned amine curing agent is not particularly limited. As the amine curing agent, hexamethylenediamine, octamethylenediamine, decamethylenediamine, 3,9-bis (3-aminopropyl) -2,4,8,10-tetraspiro [5.5] undecane, bis (4 (4) -Aminocyclohexyl) methane, metaphenylene diamine, diaminodiphenyl sulfone and the like.

  The above-mentioned acid anhydride curing agent is not particularly limited, and any acid anhydride may be used widely as long as it is used as a curing agent for thermosetting compounds such as epoxy compounds. As the above acid anhydride curing agent, phthalic anhydride, tetrahydrophthalic anhydride, trialkyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylbutenyltetrahydrophthalic anhydride , Anhydrides of phthalic acid derivatives, maleic anhydride, nadic acid anhydride, methyl nadic acid anhydride, glutaric acid anhydride, succinic acid anhydride, glycerin bis trimellitic anhydride monoacetate, and difunctional ethylene glycol bis trimellitic anhydride, etc. Acid anhydride curing agents, trifunctional acid anhydride curing agents such as trimellitic anhydride, and pyromellitic anhydride, benzophenone tetracarboxylic acid anhydride, methylcyclohexene tetracarboxylic acid anhydride, polyazelaic acid anhydride, etc. Acidic anhydride of 4 or more functional Curing agents.

  The thermal cation initiator is not particularly limited. Examples of the thermal cation initiator include iodonium-based cation curing agents, oxonium-based cation curing agents, and sulfonium-based cation curing agents. 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 and the like. Examples of the sulfonium-based cationic curing agent include tri-p-tolylsulfonium hexafluorophosphate and the like.

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

  The reaction initiation temperature of the thermosetting agent is preferably 50 ° C. or more, more preferably 70 ° C. or more, still more preferably 80 ° C. or more, preferably 250 ° C. or less, more preferably 200 ° C. or less, still more preferably 150 ° C. The temperature is particularly preferably 140 ° C. or less. When the reaction initiation temperature of the thermosetting agent is above the lower limit and below the upper limit, the solder is more efficiently disposed on the electrode. The reaction initiation temperature of the thermosetting agent is particularly preferably 80 ° C. or more and 140 ° C. or less.

  From the viewpoint of arranging the solder more efficiently on the electrode, the reaction initiation temperature of the thermosetting agent is preferably higher than the melting point of the solder in the solder particles, more preferably 5 ° C. or more, and 10 It is more preferable that the temperature be as high as ° C or more.

  The reaction initiation temperature of the thermosetting agent means the temperature at which the onset of the onset of the exothermic peak in DSC.

  The content of the thermosetting agent is not particularly limited. The content of the thermosetting agent is preferably 0.01 parts by weight or more, more preferably 1 part by weight or more, and preferably 200 parts by weight or less, more preferably 100 parts by weight of the thermosetting compound. It is 100 parts by weight or less, more preferably 75 parts by weight or less. It is easy to fully harden a conductive material as content of a thermosetting agent is more than the above-mentioned minimum. When the content of the thermosetting agent is less than or equal to the above upper limit, it becomes difficult for the surplus thermosetting agent that did not participate in curing to remain after curing, and the heat resistance of the cured product is further enhanced.

(Hardening accelerator)
The said hardening accelerator is not specifically limited. The curing accelerator acts as a curing catalyst in the reaction with the thermosetting compound. The said hardening accelerator may be used only by 1 type, and 2 or more types may be used together.

  Examples of the curing accelerator include phosphonium salts, tertiary amines, tertiary amine salts, quaternary onium salts, tertiary phosphines, crown ether complexes, and phosphonium ylides. Specifically, as the curing accelerator, an imidazole compound, isocyanurate of an imidazole compound, dicyandiamide, a derivative of dicyandiamide, a melamine compound, a derivative of a melamine compound, diaminomaleonitrile, diethylenetriamine, triethylenetetramine, 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) -2,4,8,10-Tetraoxaspiro [5,5] undecane and organophosphorus compounds such as triphenylphosphine, tricyclohexylphosphine, tributylphosphine and methyl diphenylphosphine Etc. The.

  The phosphonium salt is not particularly limited. Examples of the phosphonium salt include tetranormal butyl phosphonium bromide, tetra normal butyl phosphonium OO diethyl dithiophosphate, methyl tributyl phosphonium dimethyl phosphate, tetra normal butyl phosphonium benzotriazole, tetra normal butyl phosphonium tetrafluoroborate, and tetra normal butyl Examples include phosphonium tetraphenyl borate and the like.

  The content of the curing accelerator is appropriately selected so that the thermosetting compound cures satisfactorily. The content of the curing accelerator relative to 100 parts by weight of the thermosetting compound is preferably 0.001 parts by weight or more, more preferably 0.1 parts by weight or more, still more preferably 0.5 parts by weight or more, and further preferably Is at least 4 parts by weight, particularly preferably at least 6 parts by weight. The content of the curing accelerator relative to 100 parts by weight of the thermosetting compound is 30 parts by weight or less, more preferably 20 parts by weight or less, still more preferably 16 parts by weight or less, and particularly preferably 12 parts by weight or less. The said thermosetting compound can be favorably hardened as content of the said hardening accelerator is more than the said minimum and below the said upper limit. A solder can be arrange | positioned much more efficiently on an electrode as content of the said hardening accelerator is more than the said lower limit and below the said upper limit, and the insulation reliability between electrodes can be raised further more effectively. In particular, when the content of the curing accelerator is less than or equal to the upper limit, the minimum value of the melt viscosity can be further lowered, and the values of the melt viscosity (ηX-10) and the melt viscosity (ηX + 10) Can be made even lower.

(flux)
The conductive material may contain a flux. By using the flux, the solder can be arranged more efficiently on the electrode. The flux is not particularly limited. As the above-mentioned flux, a flux generally used for solder joint etc. can be used.

  Examples of the flux include zinc chloride, a mixture of zinc chloride and an inorganic halide, a mixture of zinc chloride and an inorganic acid, a molten salt, phosphoric acid, a derivative of phosphoric acid, an organic halide, a hydrazine, an amine compound, an organic acid and Matsusebo, etc. may be mentioned. The flux may be used alone or in combination of two or more.

  Ammonium chloride etc. are mentioned as said molten salt. Examples of the organic acids include lactic acid, citric acid, stearic acid, glutamic acid and glutaric acid. Examples of the rosin include activated rosin and non-activated rosin. The flux is preferably an organic acid having two or more carboxyl groups, or rosin. The flux may be an organic acid having two or more carboxyl groups, or may be rosin. The use of an organic acid having two or more carboxyl groups, or rosin, further enhances the conduction reliability between the electrodes.

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

  The above-mentioned rosins are rosins mainly composed of abietic acid. Examples of the rosins include abietic acid and acrylic modified rosin. The flux is preferably rosins, more preferably abietic acid. The use of this preferred flux further enhances the conduction reliability between the electrodes.

  The activation temperature (melting point) of the flux is preferably 50 ° C. or more, more preferably 70 ° C. or more, still more preferably 80 ° C. or more, preferably 200 ° C. or less, more preferably 190 ° C. or less, still more preferably 160 Or less, more preferably 150 ° C. or less, still more preferably 140 ° C. or less. When the activation temperature of the flux is above the lower limit and below the upper limit, the flux effect is more effectively exhibited, and the solder is more efficiently disposed on the electrode. The activation temperature (melting point) of the flux is preferably 80 ° C. or more and 190 ° C. or less. The activation temperature (melting point) of the flux is particularly preferably 80 ° C. or more and 140 ° C. or less.

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

  Moreover, it is preferable that the boiling point of the said flux is 200 degrees C or less.

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

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

  The flux may be dispersed in the conductive material and may be deposited on the surface of the solder particles.

  When the melting point of the flux is higher than the melting point of the solder particles, the solder particles can be efficiently aggregated in the electrode portion. This is because, when heat is applied at the time of bonding, the thermal conductivity of the electrode portion is equal to that of the connection target member portion when comparing the electrode formed on the connection target member and the connection target member portion around the electrode. The higher temperature than the thermal conductivity is attributed to the rapid temperature rise of the electrode portion. When the temperature exceeds the melting point of the solder particle, the inside of the solder particle dissolves, but the oxide film formed on the surface is not removed because it does not reach the melting point (activation temperature) of the flux. In this state, since the temperature of the electrode portion first reaches the melting point (activation temperature) of the flux, the oxide film on the surface of the solder particle which has preferentially moved onto the electrode is removed, and the solder particle is on the surface of the electrode It can spread wet. Thereby, solder particles can be efficiently aggregated on the electrode.

  It is preferable that the said flux is a flux which discharge | releases a cation by heating. The use of a flux that releases cations upon heating allows the solder to be placed more efficiently on the electrodes.

  As a flux which releases a cation by the above-mentioned heating, the above-mentioned heat cation initiator (heat cation hardening agent) is mentioned.

  From the viewpoint of arranging the solder more efficiently on the electrode, the viewpoint of enhancing the insulation reliability more effectively, and the viewpoint of enhancing the conduction reliability more effectively, the above-mentioned flux is an acid compound and a base compound It is preferable that it is a salt of

  The acid compound is preferably an organic compound having a carboxyl group. Examples of the acid compound include malonic acid which is an aliphatic carboxylic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, citric acid, malic acid and cycloaliphatic carboxylic acid Examples thereof include cyclohexylcarboxylic acid, 1,4-cyclohexyldicarboxylic acid, isophthalic acid which is an aromatic carboxylic acid, terephthalic acid, trimellitic acid, and ethylenediaminetetraacetic acid. From the viewpoint of more efficiently arranging the solder on the electrode, the viewpoint of enhancing the insulation reliability more effectively, and the viewpoint of enhancing the conduction reliability more effectively, the above-mentioned acid compound is Preferably, it is a carboxylic acid or adipic acid.

  The base compound is preferably an organic compound having an amino group. As the above-mentioned base compound, diethanolamine, triethanolamine, methyldiethanolamine, ethyldiethanolamine, cyclohexylamine, dicyclohexylamine, benzylamine, benzhydrylamine, 2-methylbenzylamine, 3-methylbenzylamine, 4-tert-butylbenzylamine , N-methylbenzylamine, N-ethylbenzylamine, N-phenylbenzylamine, N-tert-butylbenzylamine, N-isopropylbenzylamine, N, N-dimethylbenzylamine, imidazole compounds, and triazole compounds. . From the viewpoint of more efficiently arranging the solder on the electrode, the viewpoint of enhancing the insulation reliability more effectively, and the viewpoint of enhancing the conduction reliability more effectively, the above-mentioned base compound is benzylamine Is preferred.

  The content of the flux is preferably 0.5% by weight or more, preferably 30% by weight or less, and more preferably 25% by weight or less in 100% by weight of the conductive material. The conductive material may not contain flux. When the content of the flux is above the lower limit and below the 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 made more It can be removed effectively.

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

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

  The content of the filler is preferably 0% by weight (not contained) or more, preferably 5% by weight or less, more preferably 2% by weight or less, and still more preferably 1% by weight or less in 100% by weight of the conductive material. is there. A solder is arrange | positioned much more uniformly on an electrode as content of the said filler is more than the said minimum and below the said upper limit.

(Other ingredients)
The conductive material may optionally contain, for example, a filler, an extender, a softener, a plasticizer, a thixo agent, a leveling agent, a polymerization catalyst, a curing catalyst, a colorant, an antioxidant, a heat stabilizer, and a light stabilizer. It may contain various additives such as UV absorbers, lubricants, antistatic agents and flame retardants.

(Connection structure and manufacturing method of connection structure)
A 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. And a connecting portion connecting the second connection target member. In the connection structure according to the present invention, the material of the connection portion is the above-described conductive material. In the connection structure according to the present invention, the first electrode and the second electrode are electrically connected by the solder portion in the connection portion.

  The method of manufacturing a connection structure according to the present invention includes the step of disposing the conductive material on the surface of the first connection target member having the first electrode on the surface, using the above-described conductive material. In the method of manufacturing a connection structure according to the present invention, a second connection target member having a second electrode on the surface is provided on the surface of the conductive material opposite to the first connection target member. And a step of arranging so that one electrode and the second electrode face each other. In the method of manufacturing a connection structure according to the present invention, 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. And a step of electrically connecting the first electrode and the second electrode with the solder portion in the connection portion.

  In the connection structure and the method of manufacturing the connection structure according to the present invention, since the specific conductive material is used, the solder particles are easily collected between the first electrode and the second electrode, and the solder particles Line) can be placed efficiently. In addition, it is difficult for a portion of the solder particles to be disposed in the area (space) in which the electrode is not formed, and the amount of the solder particle disposed in the area in which the electrode is not formed can be considerably reduced. Therefore, the conduction reliability between the first electrode and the second electrode can be enhanced. Moreover, electrical connection between laterally adjacent electrodes, which should not be connected, can be prevented, and insulation reliability can be enhanced.

  Also, in order to efficiently dispose the solder on the electrode and considerably reduce the amount of solder disposed in the area where the electrode is not formed, the conductive material is not a conductive film but a conductive paste. Is preferred.

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

  In addition, if the conductive paste is used instead of the conductive film, the thickness of the connection portion and the solder portion can be easily adjusted by the application amount of the conductive paste. On the other hand, in the case of the conductive film, in order to change or adjust the thickness of the connection portion, it is necessary to prepare conductive films having different thicknesses or to prepare conductive films having a predetermined thickness. There is. In addition, in the case of the conductive film, compared to the conductive paste, the melt viscosity of the conductive film can not be sufficiently lowered at the melting temperature of the solder, and the aggregation of the solder particles tends to be inhibited.

  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 a conductive material according to an embodiment of the present invention.

  The connection structure 1 shown in FIG. 1 is a connection in which the first connection target member 2, the second connection target member 3, and the first connection target member 2 and the second connection target member 3 are connected. And 4 are provided. The connection portion 4 is formed of the above-described conductive material. In the present embodiment, the conductive material includes a thermosetting compound, a curing accelerator, and solder particles. In the present embodiment, a conductive paste is used as the conductive material.

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

  The first connection target member 2 has a plurality of first electrodes 2a on the surface (upper surface). The second connection target member 3 has a plurality of second electrodes 3a on the surface (lower surface). The first electrode 2a and the second electrode 3a are electrically connected by the solder portion 4A. Therefore, the first connection target member 2 and the second connection target member 3 are electrically connected by the solder portion 4A. In the connection portion 4, solder particles do not exist in a region (hardened portion 4 B portion) different from the solder portion 4 A gathered between the first electrode 2 a and the second electrode 3 a. In a region (hardened portion 4B portion) different from the solder portion 4A, there is no solder particle separated from the solder portion 4A. If the amount is small, solder particles may be present in a region (hardened portion 4B portion) different from the solder portion 4A collected between the first electrode 2a and the second electrode 3a.

  As shown in FIG. 1, in the connection structure 1, a plurality of solder particles gather between the first electrode 2 a and the second electrode 3 a, and after the plurality of solder particles are melted, a melt of the solder particles After the surface of the electrode is wetted and spread, it is solidified to form a solder portion 4A. Therefore, the connection area between the solder portion 4A and the first electrode 2a, and between the solder portion 4A and the second electrode 3a is increased. That is, by using the solder particles, the solder portion 4A, the first electrode 2a, and the solder portion are compared to the case where the conductive outer surface is a metal such as nickel, gold or copper. The contact area between 4A and the second electrode 3a is increased. This also increases the conduction reliability and the connection reliability in the connection structure 1. In the case where the conductive material contains a flux, the flux is generally gradually inactivated by heating.

  In the connection structure 1 shown in FIG. 1, all of the solder portions 4A are located in the area where the first and second electrodes 2a and 3a are facing each other. The connection structure 1X of the modified example shown in FIG. 3 differs from the connection structure 1 shown in FIG. 1 only in the connection part 4X. The connection portion 4X has a solder portion 4XA and a cured product portion 4XB. As in the connection structure 1X, most of the solder portions 4XA are located in the facing regions of the first and second electrodes 2a and 3a, and a part of the solder portions 4XA is the first and second portions. It may be protruded to the side from the field which electrode 2a, 3a has opposed. The solder portion 4XA protruding to the side from the opposing region 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 the present embodiment, the amount of solder particles separated from the solder portion can be reduced, but solder particles separated from the solder portion may be present in the cured product portion.

  The connection structure 1 can be easily obtained by reducing the amount of solder particles used. The connection structure 1X can be easily obtained by increasing the amount of solder particles used.

  In the connection structures 1 and 1X, when the first electrode 2a and the second electrode 3a face each other in the stacking direction of the first electrode 2a, the connection portions 4 and 4X, and the second electrode 3a. Preferably, the solder portions 4A and 4XA in the connection portions 4 and 4X are arranged in 50% or more of the area 100% of the opposing portions 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-described preferred embodiments, the conduction reliability can be further enhanced.

  When the portion where the first electrode and the second electrode face each other is viewed in the stacking direction of the first electrode, the connection portion, and the second electrode, the first electrode and the It is preferable that the solder part in the said connection part is arrange | positioned in 50% or more in 100% of the area of the part which opposes 2 electrodes. When the portion where the first electrode and the second electrode face each other is viewed in the stacking direction of the first electrode, the connection portion, and the second electrode, the first electrode and the It is more preferable that the solder part in the said connection part is arrange | positioned in 60% or more in 100% of area of the part which opposes 2 electrodes. When the portion where the first electrode and the second electrode face each other is viewed in the stacking direction of the first electrode, the connection portion, and the second electrode, the first electrode and the It is further preferable that the solder portion in the connection portion be disposed at 70% or more in 100% of the area of the portion facing the two electrodes. When the portion where the first electrode and the second electrode face each other is viewed in the stacking direction of the first electrode, the connection portion, and the second electrode, the first electrode and the It is particularly preferable that the solder portion in the connection portion be disposed at 80% or more of the area 100% of the portion facing the two electrodes. When the portion where the first electrode and the second electrode face each other is viewed in the stacking direction of the first electrode, the connection portion, and the second electrode, the first electrode and the It is most preferable that the solder portion in the connection portion be disposed in 90% or more of the area 100% of the portion facing the two electrodes. The conduction reliability can be further enhanced by the solder portion in the connection portion satisfying the above-described preferred embodiment.

  When the portion where the first electrode and the second electrode face each other in a direction orthogonal to the stacking direction of the first electrode, the connection portion, and the second electrode is viewed, the first It is preferable that 60% or more of the solder portion in the connection portion be disposed at a portion where the electrode and the second electrode face each other. When the portion where the first electrode and the second electrode face each other in a direction orthogonal to the stacking direction of the first electrode, the connection portion, and the second electrode is viewed, the first It is more preferable that 70% or more of the solder portion in the connection portion be disposed at a portion where the electrode and the second electrode face each other. When the portion where the first electrode and the second electrode face each other in a direction orthogonal to the stacking direction of the first electrode, the connection portion, and the second electrode is viewed, the first It is further preferable that 90% or more of the solder portion in the connection portion be disposed at a portion where the electrode and the second electrode face each other. When the portion where the first electrode and the second electrode face each other in a direction orthogonal to the stacking direction of the first electrode, the connection portion, and the second electrode is viewed, the first It is particularly preferable that 95% or more of the solder portion in the connection portion be disposed at a portion where the electrode and the second electrode face each other. When the portion where the first electrode and the second electrode face each other in a direction orthogonal to the stacking direction of the first electrode, the connection portion, and the second electrode is viewed, the first It is most preferable that 99% or more of the solder portion in the connection portion be disposed at a portion where the electrode and the second electrode face each other. The conduction reliability can be further enhanced by the solder portion in the connection portion satisfying the above-described preferred embodiment.

  Next, FIG. 2 demonstrates an example of the method of manufacturing the connection structure 1 using the electrically-conductive material which concerns on one Embodiment of this 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 and the plurality of solder particles 11A is disposed on the surface of the first connection target member 2 (first Process). The used conductive material 11 contains a thermosetting compound and a curing accelerator as the thermosetting component 11B.

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

  The method of arranging the conductive material 11 is not particularly limited, but application by a dispenser, screen printing, discharge by an inkjet device, etc. may be mentioned.

  In addition, the second connection target member 3 having the second electrode 3a on the surface (lower surface) is prepared. Next, as shown in FIG. 2B, in the conductive material 11 on the surface of the first connection target member 2, on the surface of the conductive material 11 on the opposite side to the first connection target member 2 side, The second connection target member 3 is disposed (second step). The second connection target member 3 is disposed on the surface of the conductive material 11 from the second electrode 3 a side. At this time, the first electrode 2a and the second electrode 3a are made to face each other.

  Next, the conductive material 11 is heated to the melting point or more of the solder particles 11A (third step). Preferably, the conductive material 11 is heated to a temperature higher than the curing temperature of the thermosetting component 11B (thermosetting compound). At the time of this heating, the solder particles 11A present in the region where the electrode is not formed gather between the first electrode 2a and the second electrode 3a (self-aggregation effect). When the conductive paste is used instead of the conductive film, the solder particles 11A gather more effectively between the first electrode 2a and the second electrode 3a. Also, the solder particles 11A melt and bond to each other. In addition, the thermosetting component 11B is thermally cured. As a result, as shown in FIG. 2C, the connection portion 4 connecting the first connection target member 2 and the second connection target member 3 is formed of the conductive material 11. The connection portion 4 is formed of the conductive material 11, and 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 movement of the solder particles 11A not located between the first electrode 2a and the second electrode 3a starts, 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 is completed between 3a and 3a.

  In the present embodiment, it is preferable not to apply pressure 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, at the time of formation of the connection portion 4, the solder particles 11A are more effectively gathered between the first electrode 2a and the second electrode 3a. When pressing is performed in at least one of the second step and the third step, the solder particles 11A act 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 alignment between the first electrode 2a and the second electrode 3a is shifted. Even when they are superimposed, the deviation can be corrected to connect the first electrode 2a and the second electrode 3a (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 same as the solder between the first electrode 2a and the second electrode 3a and the other conductive material. Since the direction in which the area in contact with the component is the smallest becomes energetically stable, a force acts on the connection structure having alignment that is the connection structure having the smallest area. At this time, it is desirable that the conductive material is not cured, and that the viscosity of the components other than the solder particles of the conductive material is sufficiently low at the temperature and time.

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

  The viscosity of the conductive material at the melting point of the above-mentioned solder particles is strain control 1 rad, frequency 1 Hz, heating rate 20 ° C./min, measurement temperature range 25 to 200 ° C. (using solder, using STRESSTECH (manufactured by REOLOGICA) etc. When the melting point of the particles exceeds 200 ° C., the temperature upper limit is taken as the melting point of the solder particles). From the measurement results, the viscosity at the melting point (° C.) of the solder particles is evaluated.

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

  The heating temperature in the third step is preferably 140 ° C. or more, more preferably 160 ° C. or more, preferably 450 ° C. or less, more preferably 250 ° C. or less, still more preferably 200 ° C. or less.

  As a heating method in the third step, a method of heating the entire connection structure by using a reflow furnace or using an oven at a temperature higher than the melting point of the solder particles and higher than the curing temperature of the thermosetting component There is a method of locally heating only the body connection.

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

  In addition, when heating locally with a hot plate, the metal directly under the connection should be a metal with high thermal conductivity, and other parts where heating is not desirable should be a material with low thermal conductivity such as fluorocarbon resin. Preferably, the upper surface of the hot plate is formed.

  The first and second connection target members are not particularly limited. Specifically, the first and second connection target members include semiconductor chips, semiconductor packages, LED chips, LED packages, electronic components such as capacitors and diodes, resin films, printed boards, flexible printed boards, flexible Examples include electronic components such as flat cables, rigid flexible substrates, glass epoxy substrates, and circuit substrates 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 board, a flexible flat cable, or a rigid flexible board. It is preferable that the said 2nd connection object member is a resin film, a flexible printed circuit board, a flexible flat cable, or a rigid flexible substrate. The resin film, the flexible printed circuit, the flexible flat cable and the rigid flexible substrate have properties of high flexibility and relatively light weight. When a conductive film is used to connect such a connection target member, the solder particles tend to be difficult to collect on the electrode. On the other hand, by using a conductive paste, even if a resin film, a flexible printed board, a flexible flat cable, or a rigid flexible board is used, the solder particles are efficiently collected on the electrodes, so that the conduction reliability between the electrodes is achieved. It is possible to improve sexuality sufficiently. When using a resin film, a flexible printed board, a flexible flat cable, or a rigid flexible board, compared with the case of using other connection target members such as a semiconductor chip, reliability of conduction between electrodes by not applying pressure The improvement effect can be obtained more effectively.

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

  In the connection structure according to the present invention, the first electrode and the second electrode are preferably arranged in an area array or a peripheral. When the first electrode and the second electrode are arranged in an area array or peripheral, the effect of the present invention is more effectively exhibited. The area array is a structure in which the electrodes are arranged in a grid on the surface on which the electrodes of the connection target member are arranged. The peripheral is a structure in which an electrode is disposed on the outer peripheral portion of the connection target member. In the case of a structure in which the electrodes are arranged in a comb shape, the solder particles may be aggregated along the direction perpendicular to the comb, whereas in the area array or peripheral structure described above, the entire surface on which the electrodes are arranged It is necessary for the solder particles to be uniformly aggregated. Therefore, while the amount of solder tends to be uneven in the conventional method, the effect of the present invention is more effectively exhibited in the method of the present invention.

  Hereinafter, the present invention will be specifically described by way of examples and comparative examples. The invention is not limited to the following examples.

Thermosetting compound:
Thermosetting compound 1: Phenolic novolac epoxy compound, DOW "DEN 431"
Thermosetting compound 2: Bisphenol F type epoxy compound, "YDF-8170C" manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.
Thermosetting compound 3: Bisphenol A type epoxy compound, "YD-8125" manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.
Thermosetting compound 4: Aliphatic epoxy compound, "Epolight 1600" manufactured by Kyoeisha Chemical Co., Ltd.
Thermosetting compound 5: Isocyanuric skeleton-containing epoxy compound, "TEPIC-SP" manufactured by Nissan Chemical Industries, Ltd.

Thermosetting agent:
Thermosetting agent 1: Acid anhydride curing agent, Shin Nippon Rika Co., Ltd. "Rikasid MH"
Thermosetting agent 2: Acid anhydride curing agent, Shin Nippon Rika Co., Ltd. "Rikasid TH"

Hardening accelerator:
Hardening accelerator 1: Organic phosphonium salt, "PX-4MP" manufactured by Nippon Chemical Industrial Co., Ltd., liquid at 25 ° C.

Solder particle:
Solder particles 1: SnBi solder particles, melting point 138 ° C., solder particles obtained by sorting “Sn 42 Bi 58” manufactured by Mitsui Metals, Inc., average particle diameter: 20 μm
Solder particles 2: SnBi solder particles, melting point 138 ° C., solder particles obtained by sorting “Sn 42 Bi 58” manufactured by Mitsui Metals, average particle diameter: 10 μm
Solder particles 3: SnBi solder particles, melting point 138 ° C., solder particles obtained by sorting “Sn 42 Bi 58” manufactured by Mitsui Metals, average particle diameter: 5 μm
Solder particles 4: SnBi solder particles, melting point 138 ° C., solder particles obtained by sorting “Sn 42 Bi 58” manufactured by Mitsui Metals, average particle diameter: 2 μm

flux:
Flux 1: "benzyl glutarate salt", melting point 108 ° C

How to make Flux 1:
In a glass bottle, 24 g of water as a reaction solvent and 13.212 g of glutaric acid (manufactured by Wako Pure Chemical Industries, Ltd.) were placed and dissolved until uniform at room temperature. Thereafter, 10.715 g of benzylamine (manufactured by Wako Pure Chemical Industries, Ltd.) was added, and the mixture was stirred for about 5 minutes to obtain a mixed solution. The resulting mixture was placed in a 5-10 ° C refrigerator and left overnight. The precipitated crystals were separated by filtration, washed with water and vacuum dried to obtain flux 1.

(Particle diameter of solder particle)
The particle size of the solder particles was measured as follows.

Method of measuring the particle size of solder particles:
The particle diameter of the solder particles was measured using a laser diffraction type particle size distribution measuring apparatus ("LA-920" manufactured by Horiba, Ltd.).

(Examples 1 to 17 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 amounts shown in Tables 1 and 2 below to obtain a conductive material (anisotropic conductive paste) The

(2) Preparation of Connection Structure As a second connection target member, a 250 μm copper electrode with a 400 μm pitch is arranged in an area array on the surface of the semiconductor chip body (size 5 × 5 mm, thickness 0.4 mm) A semiconductor chip having a passivation film (polyimide, thickness 5 μm, opening diameter of electrode 200 μm) formed on the outermost surface was prepared. The number of copper electrodes is 100 in total of 10 × 10 per semiconductor chip.

  As the first connection target member, on the surface of the glass epoxy substrate main body (size 20 × 20 mm, thickness 1.2 mm, material FR-4), the pattern of the electrodes of the second connection target member is the same. A glass epoxy substrate was prepared in which a copper electrode was disposed and a solder resist film was formed in a region where the copper electrode was not disposed. The step between the surface of the copper electrode and the surface of the solder resist film is 15 μm, and the solder resist film protrudes from the copper electrode.

  A conductive material (anisotropic conductive paste) immediately after preparation was coated on the upper surface of the glass epoxy substrate to a thickness of 100 μm to form a conductive material (anisotropic conductive paste) layer. Next, semiconductor chips were stacked on the top surface of the conductive material (anisotropic conductive paste) layer so that the electrodes face each other. The weight of the semiconductor chip is added to the conductive material (anisotropic conductive paste) layer. From that state, the temperature of the conductive material (anisotropic conductive paste) layer was heated to become the melting point of the solder 5 seconds after the start of the temperature rise. Further, after 15 seconds from the start of the temperature rise, the conductive material (anisotropic conductive paste) layer is heated to 160 ° C. to harden the conductive material (anisotropic conductive paste) layer, and the connection structure is obtained. Obtained. During heating, no pressure was applied.

(Evaluation)
(1) Melt viscosity of composition (conductive material excluding solder particles) excluding solder particles in conductive material Of the components shown in Tables 1 and 2 below, the components other than solder particles are shown in Tables 1 and 2 below The amount was mixed to obtain a sample for melt viscosity measurement. The obtained sample was measured under the conditions of a frequency of 2 Hz, a temperature rising rate of 0.11 ° C./second, and a measurement temperature range of 40 ° C. to 200 ° C. using a Thermo Fisher Scientific Rheometer “HAAKE MARS III”. From the obtained measurement results, the minimum value of the melt viscosity and the temperature (X ° C.) showing the minimum value of the melt viscosity were determined. Furthermore, the melt viscosity (X X -10) at X -10 ° C and the melt viscosity (+ X +10) at X + 10 ° C were determined from the obtained measurement results.

(2) Solder Residue In the obtained connection structure, the facing of the first connection object member and the second connection object member in the stacking direction of the first connection object member, the connection portion and the second connection object member The solder particles in the connecting portion are arranged in the area 100% of the opposing portion of the first connection target member and the second connection target member between the adjacent electrodes when looking at the joining portion. The area ratio X was evaluated. The solder residue was judged according to the following criteria.

[Criteria for judging solder residue]
○: Ratio X is less than 5% ○: Ratio X is 5% or more and less than 10% Δ: Ratio X is 10% or more and less than 30% ×: Ratio X is 30% or more

(3) Void In the obtained connection structure, by observing the connection portion with a scanning electron microscope, it was confirmed whether or not a void was generated in the connection portion. The void was determined based on the following criteria.

Judgment criteria of void
○: no void occurred ×: void occurred

(4) Placement accuracy of the solder on the electrode In the obtained connection structure, a portion where the first electrode and the second electrode face each other in the stacking direction of the first electrode, the connection portion, and the second electrode. The ratio Y of the area in which the solder portion in the connection portion is disposed in 100% of the area of the facing portion of the first electrode and the second electrode was evaluated. The placement accuracy of the solder on the electrode was determined according to the following criteria.

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

(5) Conduction Reliability Between Upper and Lower Electrodes In the obtained connection structure (n = 15), the connection resistance per connection point between the upper and lower electrodes was measured by the four-terminal method. The average value of connection resistance was calculated. The connection resistance can be determined from the relationship of voltage = current × resistance by measuring the voltage when a constant current flows. The conduction reliability was determined based on the following criteria.

[Criteria for continuity reliability]
○: Average value of connection resistance is 50 mΩ or less ○: Average value of connection resistance exceeds 50 mΩ and 70 mΩ or less Δ: Average value of connection resistance exceeds 70 mΩ and 100 mΩ or less ×: Average value of connection resistance exceeds 100 mΩ Or a bad connection has occurred

(6) Insulating reliability between adjacent electrodes In the obtained connection structure (n = 15), after standing for 100 hours in an atmosphere of 85 ° C. and 85% humidity, 5 V is applied between the adjacent electrodes. The resistance value was measured at 25 points. The insulation reliability was judged according to the following criteria.

[Criteria for insulation reliability]
○○: average value of connection resistance is 10 ⁷ Ω or more ○: average value of connection resistance is 10 ⁶ Ω or more and less than 10 ⁷ Ω Δ: average value of connection resistance is 10 ⁵ Ω or more and less than 10 ⁶ Ω ×: connection Average value of resistance is less than 10 ⁵ Ω

  The results are shown in Tables 1 and 2 below.

  The same tendency was observed when using a flexible printed circuit, a resin film, a flexible flat cable and a rigid flexible substrate.

Reference Signs List 1, 1X Connection structure 2 First connection target member 2a First electrode 3 Second connection target member 3a Second electrode 4, 4X Connection portion 4A, 4XA Solder portion 4B, 4XB ... Hardened part 11 ... conductive material 11A ... solder particle 11B ... thermosetting component

Claims (9)

A conductive material comprising a thermosetting compound, a curing accelerator, and solder particles,
The particle size of the solder particles is 30 μm or less,
When the melt viscosity of the composition excluding the solder particles in the conductive material is measured, and the temperature showing the minimum value of the melt viscosity is X ° C, the melt viscosity at X-10 ° C and the melt viscosity at X + 10 ° C are respectively A conductive material which is 10 Pa · s or less.   The conductive material according to claim 1, wherein the temperature indicating the minimum value of the melt viscosity is 100 ° C or more and 110 ° C or less.   The electrically conductive material of Claim 1 or 2 whose content of the said hardening accelerator with respect to 100 weight part of said thermosetting compounds is 0.1 to 20 weight part.   The conductive material according to any one of claims 1 to 3, wherein a content of the solder particles in 100 wt% of the conductive material is 55 wt% or more and 75 wt% or less.   The conductive material according to any one of claims 1 to 4, which is a conductive paste. A first connection target member having a first electrode on the surface;
A second connection target member having a second electrode on its surface;
A connection portion connecting the first connection target member and the second connection target member;
The material of the connection portion is the conductive material according to any one of claims 1 to 5,
A connection structure in which the first electrode and the second electrode are electrically connected by a solder portion in the connection portion.   The first electrode and the second electrode may be viewed in a direction in which the first electrode, the connection portion, and the second electrode are stacked, in a direction in which the first electrode and the second electrode face each other. The connection structure according to claim 6, wherein a solder portion in the connection portion is disposed in 50% or more of the 100% of the area of the portion facing the two electrodes. A process 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 5;
On the surface of the conductive material opposite to the first connection target member, a second connection target member having a second electrode on the surface, the first electrode and the second electrode face each other Arranging to
By heating the conductive material above the melting point of the solder particles, a connection portion connecting the first connection target member and the second connection target member is formed of the conductive material, and Electrically connecting the first electrode and the second electrode by means of a solder portion in the connection portion.   The first electrode and the second electrode may be viewed in a direction in which the first electrode, the connection portion, and the second electrode are stacked, in a direction in which the first electrode and the second electrode face each other. The method for manufacturing a connection structure according to claim 8, wherein a connection structure is obtained in which the solder portion in the connection portion is arranged in 50% or more of the 100% of the area of the portion facing the two electrodes. .

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