KR102431084B1 - Electroconductive paste, connection structure, and method for manufacturing connection structure - Google Patents

Abstract

Provided is a conductive paste that can control the distance between electrodes with high precision, can efficiently arrange solder particles on the electrodes, and can improve the conduction reliability between the electrodes. The electrically conductive paste which concerns on this invention connects the 1st connection object member which has a 1st electrode on the surface, and the 2nd connection object member which has a 2nd electrode on the surface, and electrically connects the said 1st electrode and the said 2nd electrode. a thermosetting component, a plurality of solder particles, and a plurality of spacers having a melting point of 250° C. or higher, wherein the average particle diameter of the spacer is larger than the average particle diameter of the solder particles.

Description

An electrically conductive paste, a bonded structure, and the manufacturing method of a bonded structure TECHNICAL FIELD

The present invention relates to a conductive paste containing solder particles. Moreover, this invention relates to the manufacturing method of the bonded structure and bonded structure using the said electrically conductive paste.

Anisotropic electrically-conductive materials, such as an anisotropic electrically-conductive paste and an anisotropic electrically-conductive film, are known widely. In the said anisotropic electrically-conductive material, electroconductive particle is disperse|distributed in binder resin.

The said anisotropic electrically-conductive material is, in order to obtain various bonding structures, for example, connection between a flexible printed circuit board and a glass substrate (FOG (Film on Glass)), and a connection between a semiconductor chip and a flexible printed board (COF (Chip on Film)). ), a connection between a semiconductor chip and a glass substrate (Chip on Glass (COG)), and a connection between a flexible printed circuit board and a glass epoxy substrate (Film on Board (FOB)).

When electrically connecting the electrode of a flexible printed circuit board, and the electrode of a glass epoxy board|substrate with the said anisotropic electrically-conductive material, the anisotropic electrically-conductive material containing electroconductive particle is arrange|positioned on a glass epoxy board|substrate. Next, a flexible printed circuit board is laminated|stacked, and it heats and pressurizes. Thereby, an anisotropic electrically-conductive material is hardened, between electrodes is electrically connected through electroconductive particle, and bonded structure is obtained.

As an example of the anisotropic conductive material, Patent Document 1 below discloses an adhesive tape comprising a resin layer containing a thermosetting resin, a solder powder, and a curing agent, wherein the solder powder and the curing agent are present in the resin layer, have. This adhesive tape is in the form of a film and is not in the form of a paste.

Moreover, in patent document 1, the adhesion|attachment method using the said adhesive tape is disclosed. Specifically, a 1st board|substrate, an adhesive tape, a 2nd board|substrate, an adhesive tape, and a 3rd board|substrate are laminated|stacked in this order from the bottom, and a laminated body is obtained. At this time, the first electrode provided on the surface of the first substrate and the second electrode provided on the surface of the second substrate face each other. Further, the second electrode provided on the surface of the second substrate and the third electrode provided on the surface of the third substrate face each other. Then, the laminate is heated at a predetermined temperature and adhered. Thereby, a bonded structure is obtained.

Further, Patent Document 2 below discloses an anisotropically conductive adhesive for electrically connecting a first electrode that is an electrode of a connection portion of a first electronic component and a second electrode that is an electrode of a connection portion of a second electronic component. The anisotropically conductive adhesive includes an insulating polymer resin, bonding particles, and spacer particles. The bonding particles are melted by heat generated by ultrasonic waves applied to the anisotropically conductive adhesive. The spacer particles have a higher melting point than the bonded particles. Solder particles are exemplified as the bonding particles.

WO2008/023452A1 Japanese Patent Publication No. 2012-532979

The adhesive tape of patent document 1 is a film form, and is not a paste form. For this reason, it is difficult to efficiently arrange the solder powder on the electrode (line). For example, in the adhesive tape described in patent document 1, a part of solder powder is easy to arrange|position also in the area|region (space) in which an electrode is not formed. The solder powder disposed in the region where no electrodes are formed does not contribute to conduction between the electrodes.

Further, even in the case of an anisotropic conductive paste containing solder powder, the solder powder may not be efficiently disposed on the electrode (line). Moreover, when the anisotropic electrically conductive paste containing solder powder is used, it is easy to generate|occur|produce the fluctuation|variation in the space|interval between electrodes after an electrically conductive connection. Moreover, also in the adhesive agent of patent document 2, bonding particles, such as a solder particle, may not be arrange|positioned efficiently on an electrode (line). Moreover, as described in Patent Document 2, even if spacer particles are used separately from bonded particles such as solder particles, the bonded particles may not be efficiently disposed on the electrode (line).

SUMMARY OF THE INVENTION An object of the present invention is to provide a conductive paste that can control the distance between electrodes with high precision, and can efficiently arrange solder particles on the electrodes, thereby improving the conduction reliability between the electrodes. Moreover, this invention provides the manufacturing method of the bonded structure and bonded structure using the said electrically conductive paste.

According to a broad aspect of the present invention, a first connection object member having a first electrode on its surface and a second connection object member having a second electrode on its surface are connected, and the first electrode and the second electrode are electrically connected A conductive paste used for provided

In one specific aspect of the conductive paste according to the present invention, the spacer is an insulating particle.

In one specific aspect of the conductive paste according to the present invention, the conductive paste is used so that the spacer is in contact with both the first connection object member and the second connection object member.

In one specific aspect of the conductive paste according to the present invention, the conductive paste is heated above the melting point of the solder particles and above the curing temperature of the thermosetting component when the first electrode and the second electrode are electrically connected, A plurality of the above-mentioned solder particles are aggregated and used to be integrated.

In one specific situation of the electrically conductive paste which concerns on this invention, the ratio of the average particle diameter of the said spacer to the average particle diameter of the said solder particle is 1.1 or more and 15 or less.

On the specific situation of the electrically conductive paste which concerns on this invention, content of the said spacer is 0.1 weight% or more and 10 weight% or less.

On the specific situation of the electrically conductive paste which concerns on this invention, the average particle diameter of the said solder particle is 1 micrometer or more and 40 micrometers or less.

On the specific situation of the electrically conductive paste which concerns on this invention, content of the said solder particle is 10 weight% or more and 80 weight% or less.

In one specific situation of the electrically conductive paste which concerns on this invention, ratio with respect to the content in the weight % unit of the said solder particle in the weight % unit of the said spacer is 2 or more and 100 or less.

According to a broad aspect of the present invention, a first connection object member having at least one first electrode on its surface, a second connection object member having at least one second electrode on its surface, the first connection object member, a connection portion for connecting the second connection object member is provided, the material of the connection portion is the above-described conductive paste, and the first electrode and the second electrode are electrically connected by a solder portion in the connection portion; The connection structure in which the said spacer is in contact with both the said 1st connection object member and the said 2nd connection object member is provided.

According to a broad aspect of the present invention, a step of disposing the conductive paste on the surface of a first connection object member having at least one first electrode on the surface using the conductive paste described above; disposing a second connection object member having at least one second electrode on the surface on a surface opposite to the first connection object member side so that the first electrode and the second electrode face each other; By heating the conductive paste above the melting point of the particles and above the curing temperature of the thermosetting component, a connection portion connecting the first connection object member and the second connection object member is formed with the conductive paste, and a step of electrically connecting the first electrode and the second electrode with a solder portion in the connection portion, and bringing the spacer into contact with both the first connection object member and the second connection object member; A method of making a structure is provided.

In one specific aspect of the method for manufacturing a bonded structure according to the present invention, when the first electrode and the second electrode are electrically connected, the first electrode and the second electrode are heated above the melting point of the solder particles and above the curing temperature of the thermosetting component, and a plurality of The solder particles are aggregated and integrated.

In one specific aspect of the manufacturing method of the connection structure which concerns on this invention, in the process of arranging the said 2nd connection object member and the process of forming the said connection part, without performing pressurization, the said electrically conductive paste contains the said 2nd connection object member. weight is applied

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 board|substrate.

The conductive paste according to the present invention contains a thermosetting component, a plurality of solder particles, and a plurality of spacers having a melting point of 250° C. or higher. When two connection object members are connected and the first electrode and the second electrode are electrically connected, the distance between the electrodes can be controlled with high precision, and the solder particles can be efficiently disposed on the electrode. , it is possible to increase the conduction reliability between the electrodes.

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which shows typically the bonded structure obtained using the electrically conductive paste which concerns on one Embodiment of this invention.
2(a) - (c) are sectional views for demonstrating each process of an example of the method of manufacturing a bonded structure using the electrically conductive paste which concerns on one Embodiment of this invention.
It is sectional drawing which shows the modified example of a connection structure.
It is sectional drawing which shows the modified example of a connection structure.

EMBODIMENT OF THE INVENTION Hereinafter, the detail of this invention is demonstrated.

(conductive paste)

The electrically conductive paste which concerns on this invention connects the 1st connection object member which has a 1st electrode on the surface, and the 2nd connection object member which has a 2nd electrode on the surface, and electrically connects the said 1st electrode and the said 2nd electrode. used to do The conductive paste according to the present invention includes a thermosetting component, a plurality of solder particles, and a plurality of spacers having a melting point of 250°C or higher.

In the conductive paste according to the present invention, the average particle diameter of the spacers is larger than the average particle diameter of the solder particles.

In the electrically conductive paste which concerns on this invention, since the said structure is employ|adopted, when electrically connecting between electrodes, the space|interval between electrodes can be controlled with high precision. In addition, when the solder particles are collected between the electrodes, the spacer ensures sufficient spacing between the upper and lower electrodes, so that a plurality of solder particles are easily collected between the upper and lower electrodes, and the plurality of solder particles are efficiently arranged on the electrodes (lines). can do. In addition, some of the plurality of solder particles are less likely to be arranged in the region (space) where the electrode is not formed, so that the amount of the solder particle arranged in the region where the electrode is not formed can be significantly reduced. Therefore, the conduction reliability between the electrodes can be improved. In addition, it is possible to prevent electrical connection between the electrodes adjacent to each other in the transverse direction, which should not be connected, so that the insulation reliability can be improved. In the present invention, by blending the spacer, the solder particles can be efficiently disposed on the electrode. Further, in the present invention, not only the spacers are simply blended, but also the average particle diameter of the spacers and the solder particles is set within a specific range, so that the solder particles can be efficiently disposed on the electrode. The use of a spacer having a specific average particle diameter greatly contributes to the improvement of the amount of solder and arrangement precision between the upper and lower electrodes to be connected.

Since the average particle diameter of the spacer is larger than the average particle diameter of the solder particles, the gap at which the solder particles can move between the first to-be-connected member and the second to-be-connected member when the solder particles move on the electrode is reduced. secured, and the movement of the solder particles is promoted. As a result, the amount of solder disposed between the upper and lower electrodes increases, so that the conduction reliability between the electrodes increases.

Further, in the present invention, it has been found that the spacer not only regulates the distance between the upper and lower electrodes by using the spacer, but also contributes to the enhancement of the cohesiveness of the solder particles by the spacer.

Moreover, in this invention, the position shift between electrodes can be prevented. In the present invention, when the second connection object member is superposed on the first connection object member to which the conductive paste has been applied, in a state where the alignment of the electrode of the first connection object member and the electrode of the second connection object member is displaced, the first Even when a connection object member and a 2nd connection object member overlap, the shift|offset|difference can be corrected and the electrode of a 1st connection object member and the electrode of a 2nd connection object member can be connected (self-alignment effect).

Moreover, when electroconductive particle provided with the solder layer arrange|positioned on the surface of the substrate particle which is not formed with solder instead of the said solder particle is used, electroconductive particle becomes difficult to collect on an electrode, and electroconductive particle Since the solder bonding property of each other is low, the electroconductive particle which moved on the electrode becomes easy to move out of an electrode. For this reason, the suppression effect of the position shift between electrodes also becomes low.

In order to more efficiently arrange the solder particles on the electrode, the viscosity (η25) at 25°C of the conductive paste is preferably 10 Pa·s or more, more preferably 50 Pa·s or more, still more preferably 100 Pa·s or more. s or more, preferably 800 Pa·s or less, more preferably 600 Pa·s or less, still more preferably 500 Pa·s or less.

The said viscosity (η25) can be suitably adjusted with the kind and compounding quantity of a compounding component. Moreover, by use of a filler, a viscosity can be made comparatively high.

The said viscosity (η25) can be measured on conditions of 25 degreeC and 5 rpm using the E-type viscometer (made by Toki Sangyo) etc., for example.

The electrically conductive paste which concerns on this invention can be used suitably for the manufacturing method of the bonded structure which concerns on this invention mentioned later, and a bonded structure.

From the viewpoint of further improving the conduction reliability, the conductive paste is heated to a temperature equal to or higher than the melting point of the solder particles and higher than the curing temperature of the thermosetting component when the first electrode and the second electrode are electrically connected. It is preferable that the solder particles are aggregated and used in an integrated manner. By integrating a plurality of solder particles, a solder portion having a larger area is formed. In one solder portion, it is preferable that two or more solder particles in the conductive paste are integrated, more preferably three or more solder particles in the conductive paste are integrated, and 5 or more solder particles in the conductive paste are integrated. more preferably.

The said electrically conductive paste is used suitably for the electrical connection of an electrode. It is preferable that the said electrically conductive paste is a circuit connection material.

Hereinafter, each component contained in the said electrically conductive paste is demonstrated.

(solder particles)

The solder particles have solder on the conductive outer surface. As for the above-mentioned solder particles, both the central portion and the conductive outer surface are formed of solder. The solder particle is a particle in which both the central portion of the solder particle and the conductive outer surface are solder.

From the viewpoint of efficiently collecting the solder particles on the electrode, it is preferable that the zeta potential of the surface of the solder particles is positive. However, in the present invention, the zeta potential of the surface of the solder particles may not be positive.

The zeta potential is measured as follows.

Method of measuring zeta potential:

0.05 g of solder particles are put in 10 g of methanol, and are uniformly dispersed by ultrasonic treatment or the like to obtain a dispersion liquid. Using this dispersion liquid, the zeta potential can also be measured at 23 degreeC by the electrophoresis measurement method using "Delsamax PRO" by Beckman Coulter.

The zeta potential of the solder particles is preferably 0 mV or more, more preferably more than 0 mV, preferably 10 mV or less, more preferably 5 mV or less, still more preferably 1 mV or less, still more preferably 0.7 mV or less, Especially preferably, it is 0.5 mV or less. If the zeta potential is equal to or less than the upper limit, it becomes difficult for the solder particles to aggregate in the electrically conductive paste before use. When the zeta potential is 0 mV or more, the solder particles are efficiently aggregated on the electrode during mounting.

Since it is easy to make the surface zeta potential positive, it is preferable that the solder particles have a solder particle body and an anionic polymer disposed on the surface of the solder particle body. It is preferable that the said solder particle is obtained by surface-treating the solder particle main body with the compound used as an anionic polymer or anionic polymer. It is preferable that the said solder particle is an anionic polymer or a surface-treated object with the compound used as anionic polymer. As for the compound used as the said anionic polymer and the said anionic polymer, respectively, only 1 type may be used and 2 or more types may be used together.

As a method of surface-treating the solder particle body with an anionic polymer, as an anionic polymer, for example, a (meth)acrylic polymer copolymerized with (meth)acrylic acid, a polyester synthesized from dicarboxylic acid and diol and having carboxyl groups at both terminals Polymer, a polymer obtained by intermolecular dehydration condensation reaction of dicarboxylic acid and having carboxyl groups at both terminals, polyester polymer synthesized from dicarboxylic acid and diamine and having carboxyl groups at both terminals, and modified polyvinyl having carboxyl groups A method of reacting the carboxyl group of the anionic polymer with the hydroxyl group on the surface of the solder particle body using alcohol (“Gosenex T” manufactured by Nippon Kosei Chemical Co., Ltd.) or the like is exemplified.

Examples of the anionic moiety of the anionic polymer include the carboxyl group, and other than that, a tosyl group (pH ₃ CC ₆ H ₄ S(=O) ₂ -), a sulfonic acid ion group (-SO ₃ -), and a phosphate ion group ( -PO ₄ -) and the like.

Further, as another method, using a compound having a functional group that reacts with a hydroxyl group on the surface of the solder particle body and having a functional group that can be polymerized by addition or condensation reaction, a method of polymerizing this compound on the surface of the solder particle body can be heard Examples of the functional group reacting with the hydroxyl group on the surface of the solder particle body include a carboxyl group and an isocyanate group, and examples of the functional group to be polymerized by addition and condensation reaction include a hydroxyl group, a carboxyl group, an amino group, and a (meth)acryloyl group. .

The weight average molecular weight of the anionic polymer is preferably 2000 or more, more preferably 3000 or more, preferably 10000 or less, more preferably 8000 or less.

When the weight average molecular weight is equal to or higher than the lower limit and equal to or lower than the upper limit, it is easy to arrange the anionic polymer on the surface of the solder particle body, and it is easy to make the zeta potential of the surface of the solder particle positive, so that the solder particle on the electrode can be arranged more efficiently.

The said weight average molecular weight shows the weight average molecular weight in polystyrene conversion measured by the gel permeation chromatography (GPC).

The weight average molecular weight of the polymer obtained by surface-treating the solder particle body with an anionic polymer compound is the amount of the polymer remaining after the solder particles are removed with dilute hydrochloric acid or the like that dissolves the solder in the solder particles and does not cause polymer decomposition. It can obtain|require by measuring a weight average molecular weight.

The solder is preferably a metal (low-melting-point metal) having a melting point of 450° C. or less. It is preferable that the said solder particle is a metal particle (low-melting-point metal particle) melting|fusing point 450 degrees C or less. The said low-melting-point metal particle|grains are particle|grains containing a low-melting-point metal. The said low-melting-point metal shows the metal whose melting|fusing point is 450 degrees C or less. The melting point of the low-melting-point metal is preferably 300°C or lower, more preferably 160°C or lower. Further, 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. to be. When the content of tin in the solder particles is equal to or greater than the lower limit, the reliability of the connection between the solder portion and the electrode is further improved.

In addition, the content of the said tin is a high frequency inductively coupled plasma emission spectroscopy apparatus ("ICP-AES" manufactured by Horiba Seisakusho) or a fluorescence X-ray analyzer ("EDX-800HS" manufactured by Shimadzu Corporation) etc. can be measured using

By using the above-mentioned solder particles, the solder is melted and joined to the electrodes, so that the solder portion conducts between the electrodes. For example, since the solder portion and the electrode easily come into surface contact instead of point contact, the connection resistance is lowered. In addition, the use of the solder particles increases the bonding strength between the solder portion and the electrode. As a result, peeling between the solder portion and the electrode becomes more difficult to occur, effectively improving the conduction reliability and connection reliability.

The metal (low-melting-point metal) constituting the solder particles is not particularly limited. It is preferable that this low-melting-point metal is tin or an alloy containing tin. Examples of the alloy include a tin-silver alloy, a tin-copper alloy, a tin-silver-copper alloy, a tin-bismuth alloy, a tin-zinc alloy, and a tin-indium alloy. In view of excellent wettability to the electrode, 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. It is more preferable that they are a tin-bismuth alloy and a tin-indium alloy.

It is preferable that the said solder particle is a filler metal whose liquidus line is 450 degrees C or less based on JIS Z3001: Welding term. As a composition of the said solder particle, the metal composition containing zinc, gold|metal|money, silver, lead, copper, tin, bismuth, indium, etc. is mentioned, for example. A tin-indium-based (117°C process) or a tin-bismuth-based (139°C process) that is low-melting and lead-free is preferred. That is, the solder particles preferably do not contain lead, contain tin and indium, or contain tin and bismuth.

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

The average particle diameter of the solder particles is preferably 0.5 µm or more, more preferably 1 µm or more, still more preferably 3 µm or more, particularly preferably 5 µm or more, preferably 100 µm or less, more preferably Less than 80 µm, still more preferably 75 µm or less, still more preferably 60 µm or less, still more preferably 40 µm or less, still more preferably 30 µm or less, still more preferably 20 µm or less, particularly preferably preferably 15 μm or less, and most preferably 10 μm or less. When the average particle diameter of the solder particles is equal to or greater than the lower limit and equal to or less than the upper limit, the solder particles can be more efficiently disposed on the electrode. It is especially preferable that the average particle diameter of the said solder particle is 3 micrometers or more and 30 micrometers or less.

The "average particle diameter" of the said solder particle shows a number average particle diameter. The average particle diameter of the solder particles can be obtained by, for example, observing 50 arbitrary solder particles with an electron microscope or an optical microscope, calculating an average value, or performing laser diffraction particle size distribution measurement.

The coefficient of variation of the particle diameter of the solder particles is preferably 5% or more, more preferably 10% or more, preferably 40% or less, and more preferably 30% or less. If the coefficient of variation of the particle diameter is equal to or greater than the lower limit and equal to or less than the upper limit, the solder particles can be more efficiently disposed on the electrode. However, the coefficient of variation of the particle diameter of the solder particles may be less than 5%.

The coefficient of variation (CV value) is expressed by the following formula.

CV value (%) = (ρ/Dn) × 100

ρ: standard deviation of the particle diameter of the solder particles

Dn: average value of particle diameters of solder particles

The shape of the solder particles is not particularly limited. A spherical shape may be sufficient as the shape of the said solder particle, and shapes other than a spherical shape, such as a flat shape, may be sufficient as it.

The content of the solder particles in 100% by weight of the conductive paste is preferably 1% by weight or more, more preferably 2% by weight or more, still more preferably 10% by weight or more, particularly preferably 20% by weight or more, particularly Preferably it is 30 weight% or more, Preferably it is 80 weight% or less, More preferably, it is 60 weight% or less, More preferably, it is 50 weight% or less. When the content of the solder particles is equal to or higher than the lower limit and equal to or lower than the upper limit, the solder particles can be more efficiently disposed on the electrode, and it is easy to arrange a large number of solder particles between the electrodes, and the conduction reliability is further improved. It is preferable that there is much content of the said solder particle from a viewpoint of further improving conduction|electrical_connection reliability.

When the line L of the portion where the electrode is formed is 50 µm or more and less than 150 µm, from the viewpoint of further improving the conduction reliability, the content of the solder particles in 100 wt% of the conductive paste is preferably 20 wt. % or more, more preferably 30 weight% or more, preferably 55 weight% or less, more preferably 45 weight% or less.

When the space (S) in the portion where the electrode is not formed is 50 µm or more and less than 150 µm, the content of the solder particles in 100 wt% of the conductive paste is preferably 30 from the viewpoint of further improving the conduction reliability. It is weight % or more, More preferably, it is 40 weight% or more, Preferably it is 70 weight% or less, More preferably, it is 60 weight% or less.

When the line L of the portion where the electrode is formed is 150 µm or more and less than 1000 µm, the content of the solder particles in 100 wt% of the conductive paste is preferably 30 wt% from the viewpoint of further improving the conduction reliability. % or more, more preferably 40 weight% or more, preferably 70 weight% or less, and more preferably 60 weight% or less.

When the space S in the portion where no electrodes are formed is 150 µm or more and less than 1000 µm, the content of the solder particles in 100 wt% of the conductive paste is preferably 30 from the viewpoint of further enhancing the conduction reliability. It is weight % or more, More preferably, it is 40 weight% or more, Preferably it is 70 weight% or less, More preferably, it is 60 weight% or less.

(spacer)

The said spacer is used suitably so that it may contact with both the said 1st connection object member and the said 2nd connection object member. Therefore, the electrically conductive paste which concerns on this invention is used suitably so that the said spacer may contact both the said 1st connection object member and the said 2nd connection object member. The spacer is formed between the first electrode (region where the first electrode is provided) of the first connection target member and the second electrode (region where the second electrode is provided) of the second connection target member. It is suitably used so that it is in contact with both sides. The spacer is suitably used so as to be in contact with both a region of the first connection object member where the first electrode is not provided and a region of the second connection object member where the second electrode is not provided. Due to the action that the solder tends to collect between the electrodes during conductive connection, the spacer tends to move to the area where the electrode is not provided. On the other hand, the spacer may be disposed between the electrodes.

The melting point of the spacer is 250° C. or higher. When the first electrode and the second electrode are electrically connected, the melting point is set high so that the spacer does not melt. The upper limit of the melting point of the spacer is not particularly limited. The melting point of the spacer may be 400° C. or less.

From the viewpoint of further preventing the melting of the spacer, the melting point of the spacer is preferably 300°C or higher, more preferably 350°C or higher.

The spacer may be a resin particle. As the material of the resin particles, for example, polyolefin resin, acrylic resin, phenol resin, melamine resin, benzoguanamine resin, urea resin, epoxy resin, unsaturated polyester resin, saturated polyester resin, polyethylene terephthalate, polysulfone, poly Divinyl such as phenylene oxide, polyacetal, polyimide, polyamideimide, polyetheretherketone, polyethersulfone, divinylbenzene polymer and vinylbenzene-styrene copolymer or divinylbenzene-(meth)acrylic acid ester copolymer A benzene-type copolymer etc. are mentioned. Since the hardness of the resin particles can be easily controlled within a suitable range, the material of the resin particles is preferably a polymer obtained by polymerizing one or two or more polymerizable monomers having an ethylenically unsaturated group. In particular, divinylbenzene polymers, polyimides or polyamideimides are preferred.

Moreover, as a material of the said spacer, silica, glass, quartz, silicon, a metal, a metal oxide, etc. other than resin are mentioned. The material of the spacer may not be metal. It is preferable that the material of the said spacer is resin, and it is more preferable that it is a divinylbenzene type copolymer. The said divinylbenzene-type copolymer contains divinylbenzene as a copolymerization component, for example.

Since a spacer may be arrange|positioned between the electrodes adjacent to the horizontal direction, it is preferable that the said spacer is insulating particle|grains from a viewpoint of further improving insulation reliability.

The average particle diameter of the spacer is preferably 10 µm or more, more preferably 20 µm or more, still more preferably 25 µm or more, preferably 100 µm or less, more preferably 75 µm or less, still more preferably 50 µm or less. When the average particle diameter of the spacer is equal to or greater than the lower limit and equal to or less than the upper limit, the distance between the electrodes can be controlled with much higher precision, and the solder particles can be more efficiently disposed on the electrode.

The "average particle diameter" of the said spacer represents a number average particle diameter. The average particle diameter of a spacer can be calculated|required, for example by observing 50 arbitrary spacers with an electron microscope or an optical microscope, calculating an average value, or performing laser diffraction type particle size distribution measurement.

The average particle diameter of the spacer is larger than the average particle diameter of the solder particles from the viewpoint of controlling the spacing between the electrodes with high precision and arranging the solder efficiently on the electrode.

From the viewpoint of controlling the spacing between the electrodes with higher precision and arranging the solder on the electrode more efficiently, the ratio of the average particle diameter of the spacer to the average particle diameter of the solder particles (average particle diameter of the spacer/solder) The average particle diameter of the particles) is preferably 1.1 or more, more preferably 1.5 or more, still more preferably 2 or more, preferably 15 or less, more preferably 10 or less, still more preferably 8 or less. From the viewpoint of controlling the spacing between the electrodes with higher precision and arranging the solder on the electrode more efficiently, the ratio of the average particle diameter of the spacer to the average particle diameter of the solder particles (average particle diameter of the spacer/of the solder particles) Average particle diameter) is preferably 1.0 or more, more preferably 1.5 or more, preferably 15 or less, more preferably 10 or less.

The coefficient of variation of the particle diameter of the spacer is preferably 3% or more, more preferably 5% or more, preferably 30% or less, and more preferably 20% or less. When the coefficient of variation of the particle diameter is equal to or greater than the lower limit and equal to or less than the upper limit, the distance between the electrodes can be controlled with much higher precision.

The coefficient of variation (CV value) is expressed by the following formula.

CV value (%) = (ρ/Dn) × 100

ρ: standard deviation of the particle diameter of the spacer

Dn: average value of the particle diameter of the spacer

From the viewpoint of controlling the spacing between the electrodes with much higher precision and arranging the solder on the electrode more efficiently, the content (in 100% by weight of the conductive paste) in the weight % unit of the solder particles is in the weight % unit of the spacer. The ratio (content of solder particles (weight%)/content of spacers (weight%)) with respect to the content (in 100% by weight of the conductive paste) is preferably 2 or more, more preferably 5 or more, and still more preferably 10 or more, Preferably it is 100 or less, More preferably, it is 80 or less, More preferably, it is 70.

From the viewpoint of controlling the spacing between the electrodes even more precisely and arranging the solder on the electrodes more efficiently, the 10% K value of the spacer (compressive modulus when compressed by 10%) is preferably 2000 N/mm ² or more. , More preferably 3500N/mm ² or more, preferably 8000 N/mm ² or less, more preferably 6000 N/mm ² or less. In addition, when the 10% K value of the spacer is equal to or greater than the lower limit and equal to or less than the upper limit, excessive movement of the spacer can be prevented after the spacer contacts both the first electrode and the second electrode, and aggregation of the solder particles is promoted. Therefore, the position shift between the first electrode and the second electrode can also be prevented, and the conduction reliability can be improved.

The 10% K value of the spacer can be measured as follows.

Using a micro compression tester, the spacer is compressed on the smooth indenter end face of a cylinder (50 µm in diameter, made of diamond) under conditions of applying a maximum test load of 90 mN at 25°C over 30 seconds. At this time, the load value (N) and the compression displacement (mm) are measured. From the obtained measured value, a compressive elastic modulus can be calculated|required by a following formula. As said micro compression tester, "Fischer Scope H-100" by a Fischer company etc. is used, for example.

K value (N/mm ² )=(3/2 ^1/2 ) F S ^-3/2 R ^-1/2

F: Load value (N) when the spacer is compressively deformed by 10%

S: Compressive displacement when the spacer is compressed by 10% (mm)

R: Radius of spacer (mm)

From the viewpoint of controlling the spacing between the electrodes more precisely and arranging the solder on the electrodes more efficiently, the compression recovery factor of the spacer is preferably 30% or more, more preferably 40% or more, and preferably 80%. Below, more preferably, it is 70 % or less. In addition, if the compression recovery factor of the spacer is greater than or equal to the lower limit and less than or equal to the upper limit, after the spacer contacts both the first electrode and the second electrode, excessive movement of the spacer can be prevented, and aggregation of the solder particles is promoted, A position shift between the first electrode and the second electrode can also be prevented, and conduction reliability can be improved.

The said compression recovery factor can be measured as follows.

Spread the spacer on the sample stage. For one sprayed spacer, using a micro compression tester, on the smooth indenter end face of a cylinder (100 µm in diameter, made of diamond), at 25°C, in the direction of the center of the spacer, until the spacer is compressively deformed by 40% A load (reverse load value) is applied. Then, unloading is performed to the load value for origin (0.40 mN). By measuring the load-compression displacement during that time, the compression recovery factor can be calculated|required from the following formula. In addition, the load speed shall be 0.33 mN/sec. As said micro compression tester, "Fischer Scope H-100" by a Fischer company etc. is used, for example.

Compression recovery rate (%) = [(L1-L2)/L1] × 100

L1: Compressive displacement from the origin load value to the reversal load value when a load is applied

L2: unloading displacement from the reversal load value when the load is released to the origin load value

In 100 weight% of the said electrically conductive paste, content of the said spacer becomes like this. Preferably it is 0.1 weight% or more, More preferably, it is 0.5 weight% or more, More preferably, it is 1 weight% or more, Preferably it is 10 weight% or less, More preferably, is 5 wt% or less, more preferably 4 wt% or less, particularly preferably 3 wt% or less. When the content of the spacer is greater than or equal to the lower limit and less than or equal to the upper limit, the distance between the electrodes can be controlled with much higher precision, the solder particles can be more efficiently disposed on the electrodes, and the number of solder particles between the electrodes can be increased. It is easy to arrange|position, and conduction|electrical_connection reliability becomes still higher.

(thermosetting compound: thermosetting component)

The thermosetting compound is a compound curable by heating. As said thermosetting compound, an oxetane compound, an epoxy compound, an episulfide compound, a (meth)acrylic compound, a phenol compound, an amino compound, an unsaturated polyester compound, a polyurethane compound, a silicone compound, a polyimide compound, etc. are mentioned. An epoxy compound is preferable from a viewpoint of making sclerosis|hardenability and a viscosity of an electrically conductive paste still more favorable and improving connection reliability further.

In 100 weight% of the said electrically conductive paste, content of the said thermosetting compound becomes like this. Preferably it is 20 weight% or more, More preferably, it is 40 weight% or more, More preferably, it is 50 weight% or more, Preferably it is 99 weight% or less, More preferably. Preferably it is 98 weight% or less, More preferably, it is 90 weight% or less, Especially preferably, it is 80 weight% or less. From a viewpoint of further improving impact resistance, it is preferable that there is much content of the said thermosetting component.

(thermosetting agent: thermosetting component)

The thermosetting agent thermosets the thermosetting compound. Examples of the thermosetting agent include thiol curing agents such as imidazole curing agents, amine curing agents, phenol curing agents and polythiol curing agents, acid anhydrides, thermal cationic initiators (thermal cationic curing agents), thermal radical generators, and the like. As for the said thermosetting agent, only 1 type may be used and 2 or more types may be used together.

An imidazole curing agent, a thiol curing agent, or an amine curing agent is preferable because the conductive paste can be cured much faster at a low temperature. Moreover, since storage stability becomes high when a sclerosing|hardenable compound which can be hardened by heating and the said thermosetting agent are mixed, a latent hardening|curing agent is preferable. The latent curing agent is preferably a latent imidazole curing agent, a latent thiol curing agent or a latent amine curing agent. Further, the thermosetting agent may be coated with a polymer material such as a polyurethane resin or a polyester resin.

It does not specifically limit as said imidazole hardening|curing agent, 2-methylimidazole, 2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-phenyl Imidazolium trimellitate, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine and 2,4-diamino-6-[2' -Methylimidazolyl-(1')]-ethyl-s-triazineisocyanuric acid adduct etc. are mentioned.

The thiol curing agent is not particularly limited, and trimethylolpropane tris-3-mercaptopropionate, pentaerythritol tetrakis-3-mercaptopropionate and dipentaerythritol hexa-3-mercaptopropionate, etc. can be heard

The amine curing agent is not particularly limited, hexamethylenediamine, octamethylenediamine, decamethylenediamine, 3,9-bis(3-aminopropyl)-2,4,8,10-tetraspiro[5.5]undecane; Bis(4-aminocyclohexyl)methane, metaphenylenediamine, diaminodiphenylsulfone, etc. are mentioned.

Examples of the thermal cationic initiator include an iodonium-based cationic curing agent, an oxonium-based cationic curing agent, and a sulfonium-based cationic curing agent. Examples of the iodonium-based cationic curing agent include bis(4-tert-butylphenyl)iodonium hexafluorophosphate. Trimethyloxonium tetrafluoroborate etc. are mentioned as said oxonium-type cation hardening|curing agent. Examples of the sulfonium-based cationic curing agent include tri-p-tolylsulfonium hexafluorophosphate.

It does not specifically limit as said thermal radical generating agent, An azo compound, an organic peroxide, etc. are mentioned. As said azo compound, azobisisobutyronitrile (AIBN) etc. are mentioned. Examples of the organic peroxide include di-tert-butyl peroxide and methyl ethyl ketone peroxide.

The reaction initiation temperature of the thermosetting agent is preferably 50°C or higher, more preferably 70°C or higher, still more preferably 80°C or higher, preferably 250°C or lower, more preferably 200°C or lower, still more preferably 150°C or lower, particularly preferably 140°C or lower. When the reaction initiation temperature of the thermosetting agent is equal to or higher than the lower limit and equal to or lower than the upper limit, the solder particles are more efficiently disposed on the electrode. It is especially preferable that the reaction initiation temperature of the said thermosetting agent is 80 degreeC or more and 140 degrees C or less.

From the viewpoint of more efficiently disposing the solder on the electrode, the reaction initiation temperature of the thermosetting agent is preferably higher than the melting point of the solder in the solder particles, more preferably 5°C or higher, and 10°C or higher. High is more preferable.

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

Content of the said thermosetting agent is not specifically limited. The content of the thermosetting agent relative to 100 parts by weight of the thermosetting compound is preferably 0.01 parts by weight or more, more preferably 1 part by weight or more, preferably 200 parts by weight or less, more preferably 100 parts by weight or less, still more preferably It is preferably 75 parts by weight or less. It is easy to fully harden an electrically conductive paste as content of a thermosetting agent is more than the said minimum. When content of a thermosetting agent is below the said upper limit, it becomes difficult to remain after hardening of the excess thermosetting agent which is not involved in hardening, and the heat resistance of hardened|cured material becomes still higher.

(flux)

The conductive paste preferably contains a flux. By using the flux, the solder can be more effectively disposed on the electrode. The flux is not particularly limited. As the flux, a flux generally used for solder bonding and the like can be used. Examples of the flux include zinc chloride, a mixture of zinc chloride and an inorganic halide, a mixture of zinc chloride and an inorganic acid, molten salt, phosphoric acid, a derivative of phosphoric acid, an organic halide, hydrazine, an organic acid, and pine resin. have. As for the said flux, only 1 type may be used and 2 or more types may be used together.

Ammonium chloride etc. are mentioned as said molten salt. Examples of the organic acid include lactic acid, citric acid, stearic acid, glutamic acid and glutaric acid. Examples of the pine resin include activated pine resin and inactivated pine resin. The flux is preferably an organic acid having two or more carboxyl groups and pine resin. The flux may be an organic acid having two or more carboxyl groups, or may be pine resin. By use of the organic acid and pine paper which have two or more carboxyl groups, the conduction|electrical_connection reliability between electrodes becomes still higher.

The pine resin is a rosin containing abietic acid as a main component. It is preferable that it is rosins, and, as for a flux, it is more preferable that it is abietic acid. By using this preferred flux, the conduction reliability between the electrodes is further improved.

The active temperature (melting point) of the flux is preferably 50°C or higher, more preferably 70°C or higher, still more preferably 80°C or higher, preferably 200°C or lower, more preferably 190°C or lower, even more preferably Preferably it is 160 degrees C or less, More preferably, it is 150 degrees C or less, More preferably, it is 140 degrees C or less. When the active temperature of the flux is equal to or higher than the lower limit and equal to or lower than the upper limit, the flux effect is more effectively exhibited, and the solder particles are more efficiently disposed on the electrode. The flux activation temperature is preferably 80°C or higher and 190°C or lower. It is particularly preferable that the activation temperature of the flux is 80°C or higher and 140°C or lower.

Examples of the flux having a melting point of 80°C or higher and 190°C or lower include succinic acid (melting point 186°C), glutaric acid (melting point 96°C), adipic acid (melting point 152°C), pimelic acid (melting point 104°C), suberic acid ( Dicarboxylic acid, such as melting|fusing point 142 degreeC), benzoic acid (melting point 122 degreeC), malic acid (melting point 130 degreeC), etc. are mentioned.

In addition, it is preferable that the boiling point of the flux is 200° C. or less.

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

From the viewpoint of more efficiently disposing the solder 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 higher, and still more preferably 10°C or higher.

When the melting point of the flux is higher than the melting point of the solder, it is possible to efficiently aggregate the solder particles in the electrode portion. This is because, when heat is applied at the time of bonding, when the electrode formed on the connection object member is compared with the portion of the connection object member around the electrode, the thermal conductivity of the electrode portion is higher than the thermal conductivity of the portion of the connection object member around the electrode, so that the electrode This is due to the rapid increase in temperature of the portion. At the stage exceeding the melting point of the solder particles, the inside of the solder particles is melted, but the oxide film formed on the surface has not reached the melting point (activation temperature) of the flux and is not removed. In this state, since the temperature of the electrode portion first reaches the melting point (active temperature) of the flux, the oxide film on the surface of the solder particles that preferentially reached on the electrode is removed, so that the solder particles can spread on the surface of the electrode have. Thereby, the solder particles can be efficiently aggregated on the electrode.

The flux may be dispersed in the conductive paste or adhered to the surface of the solder particles.

Preferably, the flux is a flux that releases positive ions by heating. By using a flux that emits positive ions by heating, solder particles can be more efficiently disposed on the electrode.

In 100 weight% of the said electrically conductive paste, content of the said flux becomes like this. Preferably it is 0.5 weight% or more, Preferably it is 30 weight% or less, More preferably, it is 25 weight% or less. The said electrically conductive paste does not need to contain a flux. When the flux content is greater than or equal to the lower limit and less than or equal to the upper limit, an oxide film is more difficult to form on the surfaces of the solder and the electrode, and the oxide film formed on the surface of the solder and the electrode can be removed more effectively.

(filler)

You may add a filler to the said electrically conductive paste. An organic filler may be sufficient as a filler, and an inorganic filler may be sufficient as it. By adding the filler, the distance at which the solder particles aggregate can be suppressed, and the solder particles can be uniformly aggregated over all the electrodes of the substrate.

In 100 weight% of the said electrically conductive paste, content of the said filler becomes like this. Preferably it is 0 weight% or more, Preferably it is 5 weight% or less, More preferably, it is 2 weight% or less, More preferably, it is 1 weight% or less. If the content of the filler is greater than or equal to the lower limit and equal to or less than the upper limit, the solder particles are more efficiently disposed on the electrode.

(other ingredients)

The electrically conductive paste, if necessary, for example, various additives such as fillers, extenders, softeners, plasticizers, polymerization catalysts, curing catalysts, colorants, antioxidants, heat stabilizers, light stabilizers, ultraviolet absorbers, lubricants, antistatic agents and flame retardants may contain

(A bonded structure and a manufacturing method of a bonded structure)

A connection structure according to the present invention includes a first connection object member having at least one first electrode on its surface, a second connection object member having at least one second electrode on its surface, the first connection object member; The connection part which connects the said 2nd connection object member is provided. In the bonded structure according to the present invention, the connection portion is formed of the above-described conductive paste, and is a cured product of the above-described conductive paste. In the connection structure which concerns on this invention, the material of the said connection part is the electrically conductive paste mentioned above. In the connection structure which concerns on this invention, the said 1st electrode and the said 2nd electrode are electrically connected by the solder part in the said connection part. It is preferable that the said spacer is in contact with both the said 1st connection object member and the said 2nd connection object member.

The manufacturing method of the bonded structure which concerns on this invention uses the above-mentioned electrically conductive paste, The process of arrange|positioning the said electrically conductive paste on the surface of the 1st connection object member which has at least one 1st electrode on the surface, The said electrically conductive paste disposing a second connection object member having at least one second electrode on the surface on a surface opposite to the first connection object member side so that the first electrode and the second electrode face; By heating the conductive paste above the melting point of the solder particles and above the curing temperature of the thermosetting component, a connection portion connecting the first connection object member and the second connection object member is formed with the conductive paste, and further comprising a step of electrically connecting the first electrode and the second electrode with a solder portion in the connection portion. It is preferable to make the said spacer contact both of the said 1st connection object member and the said 2nd connection object member.

In the bonded structure according to the present invention and the method for manufacturing the bonded structure according to the present invention, since a specific conductive paste is used, a plurality of solder particles are easily collected between the first electrode and the second electrode, and the plurality of solder particles are used as an electrode. It can be arranged efficiently on (line). In addition, some of the plurality of solder particles are less likely to be arranged in the region (space) where the electrode is not formed, so that the amount of the solder particle arranged in the region where the electrode is not formed can be significantly reduced. Therefore, the conduction reliability between the first electrode and the second electrode can be improved. In addition, it is possible to prevent electrical connection between the electrodes adjacent to each other in the transverse direction, which should not be connected, so that the insulation reliability can be improved.

From the viewpoint of further improving the conduction reliability, when the first electrode and the second electrode are electrically connected, the plurality of the solder particles are aggregated by heating above the melting point of the solder particles and above the curing temperature of the thermosetting component. It is preferable to make it unified.

In addition, in order to efficiently arrange a plurality of solder particles on the electrode and to significantly reduce the amount of solder particles to be placed in a region where no electrodes are formed, it is necessary to use a conductive paste, not a conductive film, The inventors found out.

In the present invention, another method of efficiently collecting a plurality of solder particles between the electrodes may also be employed. As a method of efficiently collecting a plurality of solder particles between electrodes, when heat is applied to the conductive paste between the first connection object member and the second connection object member, the viscosity of the conductive paste decreases due to the heat, The method of generating the convection of the electrically conductive paste between a 1st connection object member and a 2nd connection object member, etc. are mentioned. In this method, a method of generating convection due to a difference in heat capacity between an electrode on the surface of a connection object member and other surface members, a method of generating convection by converting moisture in the connection object member into water vapor by heat, and The method etc. which generate|occur|produce convection by the temperature difference of a 1st connection object member and a 2nd connection object member are mentioned. Thereby, the solder particle in an electrically conductive paste can be efficiently moved to the surface of an electrode.

In the present invention, a method of selectively aggregating solder particles on the surface of the electrode may also be employed. As a method for selectively aggregating solder particles on the surface of an electrode, a connection object member formed of an electrode material having good wettability of molten solder particles and other surface material having poor wettability of molten solder particles is selected, A method of selectively attaching molten solder particles that have reached the surface to an electrode, and melting and attaching separate solder particles to the molten solder particles, electrode materials with good thermal conductivity, and other surface materials with poor thermal conductivity A method of selectively melting solder on an electrode by increasing the temperature of the electrode relative to other surface members when heat is applied by selecting a member to be connected formed by, negative charge present on an electrode formed by metal A method of selectively aggregating solder particles on an electrode using solder particles treated to have a positive charge against The method of selectively aggregating solder particle|grains on an electrode, etc. are mentioned.

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

In the manufacturing method of the connection structure which concerns on this invention, in the process of arranging the said 2nd connection object member and the process of forming the said connection part, the weight of the said 2nd connection object member is applied to the said electrically conductive paste without performing pressurization, or or at least one of the step of arranging the second connection target member and the step of forming the connection portion, pressurizing, and in both the step of arranging the second connection object member and the step of forming the connection portion, It is preferable that the pressure of pressurization is less than 1 MPa. By not applying a pressing pressure of 1 MPa or more, aggregation of the solder particles is significantly promoted. From a viewpoint of suppressing the curvature of a connection object member, in the manufacturing method of the bonded structure which concerns on this invention, at least one of the process of arranging the said 2nd connection object member and the process of forming the said connection part pressurizes, and In both the process of arranging the connection object member and the process of forming the said connection part, the pressure of pressurization may be less than 1 MPa. When performing pressurization, you may press only in the process of arranging the said 2nd connection object member, You may press only in the process of forming the said connection part, The process of arranging the said 2nd connection object member, and the said connection part You may pressurize in both of the process of formation. When the pressure of pressurization is less than 1 MPa, the case where no pressurization is included is included. In the case of pressurization, the pressure of pressurization is preferably 0.9 MPa or less, more preferably 0.8 MPa or less. In the case where the pressing pressure is 0.8 MPa or less, the aggregation of the solder particles is further remarkably promoted compared to the case in which the pressing pressure exceeds 0.8 MPa.

In the manufacturing method of the bonded structure which concerns on this invention, in the process of arranging the said 2nd connection object member and the process of forming the said connection part, the weight of the said 2nd connection object member is applied to the said electrically conductive paste without performing pressurization. Preferably, in the step of arranging the second connection target member and the step of forming the connection portion, a pressing pressure exceeding the force of the weight of the second connection target member is not applied to the conductive paste. In these cases, the uniformity of the amount of solder can be further improved in the plurality of solder portions. In addition, the thickness of the solder portion can be increased more effectively, the plurality of solder particles are more likely to gather between the electrodes, and the plurality of solder particles can be arranged on the electrode (line) more efficiently. In addition, since some of the plurality of solder particles are less likely to be disposed in the region (space) where the electrode is not formed, the amount of the solder particle disposed in the region where the electrode is not formed can be further reduced. Accordingly, the conduction reliability between the electrodes can be further improved. Moreover, the electrical connection between the electrodes adjacent to the lateral direction which should not be connected can be prevented further more, and insulation reliability can be improved further.

In addition, in the step of disposing the second connection object member and the step of forming the connection portion, when the weight of the second connection object member is applied to the conductive paste without applying pressure, an electrode is formed before the connection portion is formed The solder particles arranged in the non-prepared region (space) are more likely to be collected between the first electrode and the second electrode, so that a plurality of solder particles can be arranged on the electrode (line) more efficiently. Also, the present inventors found out. In the present invention, a combination of a configuration in which a conductive paste is used instead of a conductive film and a configuration in which the weight of the second connection object member is applied to the conductive paste without applying pressure is used in combination, according to the present invention. It is of great significance because the effect is obtained at a higher level.

Further, WO2008/023452A1 describes that from the viewpoint of efficiently moving the solder powder by flowing it on the electrode surface, it is sufficient to pressurize it with a predetermined pressure during bonding. , for example, 0 MPa or more, preferably 1 MPa or more, and even if the pressure intentionally applied to the adhesive tape is 0 MPa, due to the weight of the member disposed on the adhesive tape, a predetermined pressure is applied to the adhesive tape. What may be added is described. In WO2008/023452A1, it is described that the pressure to be intentionally applied to the adhesive tape may be 0 MPa, but the difference in the effect between the case where a pressure exceeding 0 MPa is applied and the case where it is set as 0 MPa is not described at all. Moreover, in WO2008/023452A1, it is not recognized at all also about the importance of using the electrically conductive paste of a paste form instead of a film form.

Moreover, when an electrically conductive paste is used instead of an electrically conductive film, it will become easy to adjust the thickness of a connection part and a solder part according to the application amount of an electrically conductive paste. On the other hand, in a conductive film, in order to change or adjust the thickness of a connection part, there exists a problem that the conductive film of mutually different thickness must be prepared, or the conductive film of predetermined thickness must be prepared. In addition, in the conductive film, the melt viscosity of the conductive film cannot be sufficiently lowered at the melting temperature of the solder, and there is a problem that the aggregation of the solder particles is inhibited.

EMBODIMENT OF THE INVENTION Hereinafter, specific embodiment of this invention is described, referring drawings.

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which shows typically the bonded structure obtained using the electrically conductive paste which concerns on one Embodiment of this invention.

The connection structure 1 shown in FIG. 1 connects the 1st connection object member 2, the 2nd connection object member 3, the 1st connection object member 2, and the 2nd connection object member 3 A connecting portion 4 is provided. The connecting portion 4 is formed of a thermosetting compound, a thermosetting agent, a plurality of solder particles, and a conductive paste containing a plurality of spacers 5 . The thermosetting compound and the thermosetting agent are thermosetting components.

The connecting portion 4 includes a solder portion 4A in which a plurality of solder particles are gathered and joined to each other, a cured product portion 4B in which a thermosetting component is thermoset, and a spacer 5 .

The 1st connection object member 2 has the some 1st electrode 2a on the surface (upper surface). The 2nd connection object member 3 has the some 2nd electrode 3a on the surface (lower surface). The first electrode 2a and the second electrode 3a are electrically connected by a solder portion 4A. Therefore, the 1st connection object member 2 and the 2nd connection object member 3 are electrically connected by the solder part 4A. In addition, in the connection part 4, in the area|region (hardened|cured material part 4B part) different from the solder part 4A gathered between the 1st electrode 2a and the 2nd electrode 3a, solder is not present. . In a region different from the solder portion 4A (the portion of the cured product portion 4B), the solder spaced apart from the solder portion 4A does not exist. Moreover, if it is a small amount, solder may exist in the area|region (hardened|cured material part 4B part) different from the solder part 4A gathered between the 1st electrode 2a and the 2nd electrode 3a.

The spacer 5 is in contact with both the first electrode 2a of the first connection object member 2 and the second electrode 3a of the second connection object member 3 . The spacer 5 regulates the interval between the first connection object member 2 and the second connection object member 3 and regulates the interval between the first electrode 2a and the second electrode 3a. . The spacer 5 is formed between a region where the first electrode 2a of the first connection object member 2 is not provided and a region where the second electrode 3a of the second connection object member 3 is not provided. You may be in contact with both sides.

As shown in Fig. 1, in the bonded structure 1, a plurality of solder particles are collected between the first electrode 2a and the second electrode 3a, and after the plurality of solder particles are melted, the solder particles After the molten material spreads on the surface of the electrode, it is solidified and a solder portion 4A is formed. For this reason, the connection area between the solder part 4A and the 1st electrode 2a, and the solder part 4A and the 2nd electrode 3a becomes large. That is, by using solder particles, the solder portion 4A, the first electrode 2a, and the solder portion 4A are compared with the case where the conductive particles having a conductive outer surface of a metal such as nickel, gold or copper are used. and the contact area between the second electrode 3a and the second electrode 3a increases. For this reason, the conduction|electrical_connection reliability and connection reliability in the connection structure 1 become high. Moreover, the electrically conductive paste may contain the flux. When a flux is used, the flux is generally deactivated gradually by heating.

Moreover, in the connection structure 1 shown in FIG. 1, all of the solder parts 4A are located in the area|region which opposes between the 1st, 2nd electrodes 2a, 3a. The connection structure 1X of the modification shown in FIG. 3 differs from the connection structure 1 shown in FIG. 1 only in the connection part 4X. The connecting portion 4X includes a solder portion 4XA, a cured product portion 4XB, and a spacer 5X. Like the connection structure 1X, most of the solder portion 4XA is located in the regions where the first and second electrodes 2a and 3a face each other, and a part of the solder portion 4XA is formed with the first and second electrodes 2a and 3a. You may protrude laterally from the opposing area|region of the electrodes 2a, 3a. The solder portion 4XA protruding laterally from the opposing regions of the first and second electrodes 2a and 3a is a part of the solder portion 4XA and is not a solder spaced apart from the solder portion 4XA. . Moreover, in this embodiment, although the amount of solder spaced apart from a solder part can be reduced, the solder spaced apart from a solder part may exist in the hardened|cured material part.

When the amount of the solder particles used is reduced, it becomes easy to obtain the bonded structure 1 . When the usage-amount of a solder particle is increased, it will become easy to obtain the bonded structure 1X. In addition, it is sufficient that the solder is spread on the surface of the electrode, and the solder does not necessarily have to collect between the upper and lower electrodes.

Moreover, like the connection structure 1Y shown in FIG. 4, it has the 1st electrode 2a on the surface, and also the 1st convex part (1st convex part ( 2y) of the first connection object member 2Y, the second electrode 3a on the surface, and the second convex portion 3y in the region where the second electrode 3a on the side of the second electrode 3a does not exist. ), you may use the 2nd connection object member 3Y which has. The first convex portion 2y protrudes more than the first electrode 2a. The second convex portion 3y protrudes more than the second electrode 3a. The interval between the first convex portion 2y and the second convex portion 3y is narrower than the interval between the first electrode 2a and the second electrode 3a. In this connection structure 1Y, the connection part 4Y has the solder part 4YA, the hardened|cured material part 4YB, and the spacer 5Y. In the connection structure 1Y, the spacer 5Y is in contact with both the first convex part 2y and the second convex part 3y. As a result, the space between the first electrode 2a and the second electrode 3a is regulated by the spacer 5Y.

From the viewpoint of further improving the conduction reliability, when the first electrode and the second electrode face each other in the stacking direction of the first electrode, the connecting portion, and the second electrode, the first electrode and the second electrode are viewed 50% or more (preferably 60% or more, more preferably 70% or more, still more preferably 80% or more, particularly preferably 90% or more) in 100% of the area of the portion facing each other with the second electrode It is preferable that the solder part in the said connection part is arrange|positioned at the

From the viewpoint of further improving the conduction reliability, when the first electrode and the second electrode face each other in a direction orthogonal to the stacking direction of the first electrode, the connecting portion, and the second electrode, the It is preferable that 70% or more of the solder portion in the connection portion is disposed in a portion opposite to the first electrode and the second electrode.

Next, an example of the method of manufacturing the bonded structure 1 using the electrically conductive paste which concerns on one Embodiment of this invention is demonstrated.

First, the 1st connection object member 2 which has the 1st electrode 2a on the surface (upper surface) is prepared. Next, as shown in Fig. 2A, on the surface of the first connection object member 2, a thermosetting component 11B, a plurality of solder particles 11A, and a spacer 5 are included. The electrically conductive paste 11 is arrange|positioned (1st process). The conductive paste 11 is arrange|positioned on the surface in which the 1st electrode 2a of the 1st connection object member 2 was provided. After the conductive paste 11 is disposed, the solder particles 11A are disposed both on the first electrode 2a (line) and on the region (space) where the first electrode 2a is not formed.

Although it does not specifically limit as an arrangement|positioning method of the electrically conductive paste 11, Application|coating by a dispenser, screen printing, discharge by an inkjet apparatus, etc. are mentioned.

Moreover, the 2nd connection object member 3 which has the 2nd electrode 3a on the surface (lower surface) is prepared. Next, as shown in FIG.2(b), in the conductive paste 11 on the surface of the 1st connection object member 2, the 1st connection object member 2 side of the electrically conductive paste 11 is different. On the opposite surface, the 2nd connection object member 3 is arrange|positioned (2nd process). On the surface of the electrically conductive paste 11, the 2nd connection object member 3 is arrange|positioned from the 2nd electrode 3a side. At this time, the first electrode 2a and the second electrode 3a face each other.

Next, the conductive paste 11 is heated above the melting point of the solder particles 11A and above the curing temperature of the thermosetting component 11B (third step). That is, the conductive paste 11 is heated to a temperature higher than or equal to a lower temperature within the melting point of the solder particles 11A and the curing temperature of the thermosetting component 11B. At the time of this heating, the solder particles 11A existing in the region where the electrode is not formed are collected between the first electrode 2a and the second electrode 3a (self-aggregation effect). In this embodiment, since the conductive paste is used instead of the conductive film, and the conductive paste has a specific composition, the solder particles 11A are effectively interposed between the first electrode 2a and the second electrode 3a. gather Further, the solder particles 11A are melted and joined to each other. Moreover, the thermosetting component 11B thermosets. As a result, as shown in FIG.2(c), the connection part 4 which connects the 1st connection object member 2 and the 2nd connection object member 3 is formed with the electrically conductive paste 11. . The connection part 4 is formed by the conductive paste 11, the solder part 4A is formed by joining the some solder particle 11A, and the hardened|cured material part 4B is thermosetted by the thermosetting component 11B. is formed When the solder particles 11A sufficiently move, the movement of the solder particles 11A not positioned between the first electrode 2a and the second electrode 3a starts, and then the first electrode 2a and the second electrode 3a start to move. It is not necessary to keep the temperature constant until the movement of the solder particles 11A between the electrodes 3a is completed.

In this embodiment, pressurization is not performed in the said 2nd process and the said 3rd process. In the present embodiment, the weight of the second connection object member 3 is applied to the conductive paste 11 . For this reason, at the time of formation of the connection part 4, the solder particle 11A effectively collects between the 1st electrode 2a and the 2nd electrode 3a. Further, the connecting portion 4X includes a solder portion 4XA, a cured product portion 4XB, and a spacer 5 . The spacer 5 is easily extruded by the aggregation of the solder particles 11A. When forming the connection portion 4 , the spacer 5 can be brought into contact with both the first connection object member 2 and the second connection object member 3 . Specifically, at the time of forming the connection part 4, the spacer 5 can make contact with both the 1st electrode 2a and the 2nd electrode 3a. In addition, if pressurization is performed in at least one of the second step and the third step, the tendency for the solder particles to collect between the first electrode and the second electrode tends to be inhibited. This was discovered by the present inventors.

In addition, in this embodiment, since pressurization is not performed, when a 2nd connection object member is superposed on the 1st connection object member to which the electrically conductive paste was apply|coated, the electrode of the 1st connection object member and the 2nd connection object member Even when the first connection object member and the second connection object member overlap in a state where the alignment of the electrodes is misaligned, the misalignment is corrected so that the electrode of the first connection object member and the electrode of the second connection object member can be connected Yes (self-alignment effect). This means that the molten solder self-aggregated between the electrode of the first connection object member and the electrode of the second connection object member is self-aggregated, and the solder and conductive paste between the electrode of the first connection object member and the electrode of the second connection object member. This is because the minimum area in contact with the other components of is energetically stable, and the force acting on the connection structure that was the alignment that is the connection structure with the minimum area acts. At this time, it is preferable that the electrically conductive paste is not hardened|cured and that the viscosity of components other than the solder particle of an electrically conductive paste is low enough from the temperature and time.

When a spacer exists between a 1st connection object member and a 2nd connection object member, the distance between the electrode of a 1st connection object member and the electrode of a 2nd connection object member can fully be ensured. Thereby, the space where the solder particles aggregate can be secured, and the aggregation property of the solder particles can be improved. In addition, since a sufficient amount of solder can be secured between the electrode of the first connection object member and the electrode of the second connection object member, the self-alignment effect is easily exhibited even when the opposing electrodes are displaced and overlapped. . With respect to a preferable amount of displacement of the electrode after conductive connection, when the width of the electrode is L, preferably 0L or more (0 or more), preferably 0.9L or less, more preferably 0.75L or less. In addition, with respect to the preferable deviation|shift amount X after conductive connection, when the particle diameter of a spacer is R, Preferably it is 0R or more (0 or more), Preferably it is 3R or less, More preferably, it is 2R or less.

The viscosity of the conductive paste at the melting point temperature of the solder 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 it is below a predetermined viscosity, solder particles can be aggregated efficiently, and if it is above a predetermined viscosity, the void in a connection part can be suppressed and the protrusion of the electrically conductive paste other than a connection part can be suppressed.

In this way, the bonded structure 1 shown in FIG. 1 is obtained. In addition, the said 2nd process and the said 3rd process may be performed continuously. Moreover, after performing the said 2nd process, the laminated body of the 1st connection object member 2 obtained, the electrically conductive paste 11, and the 2nd connection object member 3 is moved to a heating part, and the said 3rd process is carried out may be done In order to perform the said heating, the said laminated body may be arrange|positioned on a heating member, and the said laminated body may be arrange|positioned in the heated space.

The heating temperature in the third step is not particularly limited as long as it is equal to or higher than the melting point of the solder particles and higher than or equal to the curing temperature of the thermosetting component. The heating temperature is preferably 140°C or higher, more preferably 160°C or higher, preferably 450°C or lower, more preferably 250°C or lower, still more preferably 200°C or lower.

Before the third step, a heating step may be provided in order to equalize the aggregation of the solder particles before melting. The heating temperature in the heating step is preferably 60°C or higher, more preferably 80°C or higher, preferably 130°C or lower, and more preferably 120°C or lower under temperature conditions, preferably 5 seconds or more, preferably Keep it under 120 seconds. By this heating step, the thermosetting component is reduced in viscosity by heat, and the solder particles before melting are agglomerated to form a mesh structure, and when the solder particles are melted and aggregated in the third step, the amount of solder particles that do not aggregate can be reduced. have.

In the third step, preferably the melting point (°C) of the solder or more, more preferably the melting point (°C) of the solder + 5°C or more, preferably the melting point (°C) of the solder + 20°C or less, more preferably the solder At a temperature below the melting point (°C) of +10°C, preferably 10 seconds or more, preferably 120 seconds or less, the temperature may be raised to the curing temperature of the thermosetting component. Thereby, aggregation of the solder particles can be completed in a state where the viscosity of the thermosetting component is low before the thermosetting component is cured, and aggregation of the solder particles can be performed more uniformly.

The temperature increase rate in the third step is preferably 50°C/sec or less, more preferably 20°C/sec or less, still more preferably 10°C/sec or less with respect to the temperature increase from 30°C to the melting point of the solder particles. , Preferably it is 1 degreeC/sec or more, More preferably, it is 5 degrees C/sec or more. When the temperature increase rate is equal to or higher than the lower limit, the aggregation of the solder particles becomes even more uniform. When the temperature increase rate is equal to or less than the upper limit, an excessive increase in viscosity due to the progress of curing of the thermosetting component is suppressed, and aggregation of the solder particles is less likely to be inhibited.

In addition, after the said 3rd process, a 1st connection object member or a 2nd connection object member can be peeled from a connection part for the purpose of correction of a position, or re-performing of manufacture. The heating temperature for performing this peeling is preferably not less than the melting point of the solder particles, more preferably not less than the melting point (°C) of the solder particles + 10°C. The heating temperature for performing this peeling may be the melting point (°C) of the solder particles + 100°C or less.

As a heating method in the said 3rd process, the method of heating the whole bonded structure using a reflow furnace or oven to more than the melting|fusing point of a solder particle and the hardening temperature of a thermosetting component, or only the connection part of a bonded structure The method of heating locally is mentioned.

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

In addition, when heating locally with a hot plate, the upper surface of the hot plate is made of a material with low thermal conductivity, such as fluororesin, for the parts where heating is not desirable, the metal directly below the connection part is made of high thermal conductivity. It is preferable to form

The said 1st, 2nd connection object member is not specifically limited. Specific examples of the first and second connection target members include electronic components such as semiconductor chips, semiconductor packages, LED chips, LED packages, capacitors and diodes, and resin films, printed circuit boards, flexible printed circuit boards, flexible flat cables, Electronic components, such as circuit boards, such as a rigid flexible board|substrate, a glass epoxy board|substrate, and a glass board|substrate, etc. are mentioned. It is preferable that the said 1st, 2nd connection object member is an electronic component.

It is preferable that at least one of a said 1st connection object member and a said 2nd connection object member is a resin film, a flexible printed circuit board, a flexible flat cable, or a rigid flexible board|substrate. 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 board|substrate. A resin film, a flexible printed circuit board, a flexible flat cable, and a rigid flexible board|substrate have the property of high flexibility and comparatively light weight. When a conductive film is used for the connection of such a connection object member, there exists a tendency for solder particle|grains to be hard to collect on an electrode. On the other hand, even if it uses a resin film, a flexible printed circuit board, a flexible flat cable, or a rigid flexible board|substrate, the conduction|electrical_connection reliability between electrodes can fully be improved by collecting solder particles efficiently on an electrode using an electrically conductive paste. When a resin film, a flexible printed circuit board, a flexible flat cable, or a rigid flexible board is used, compared with the case where other connection object members such as a semiconductor chip are used, the effect of improving the conduction reliability between the electrodes by not applying pressure is improved. obtained more effectively.

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

Preferably, the first electrode and the second electrode are arranged in an area array or peripheral. When the electrodes are arranged in an area array or a peripheral surface, the effect of the present invention is more effectively exhibited. An area array is a structure in which the electrode is arrange|positioned in the grid|lattice shape on the surface where the electrode of a connection object member is arrange|positioned. A peripheral is a structure in which the electrode is arrange|positioned in the outer peripheral part of a connection object member. In the case of a structure in which the electrodes are arranged in a comb-tooth shape, the solder particles only need to be agglomerated along the direction perpendicular to the comb teeth, whereas in the above structure, the solder particles are uniformly aggregated over the entire surface on the surface where the electrodes are arranged. Therefore, in the conventional method, the amount of solder tends to be non-uniform, whereas in the method of the present invention, the effect of the present invention is more effectively exhibited.

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

Polymer A:

Synthesis of reaction product of bisphenol F with 1,6-hexanediol diglycidyl ether and bisphenol F type epoxy resin (polymer A):

100 parts by weight of bisphenol F (including 4,4'-methylenebisphenol, 2,4'-methylenebisphenol, and 2,2'-methylenebisphenol in a weight ratio of 2:3:1), 1,6-hexanediol diglycerol 130 parts by weight of cidyl ether, 5 parts by weight of bisphenol F-type epoxy resin ("EPICLON EXA-830CRP" manufactured by DIC), 10 parts by weight of resorcinol-type epoxy compound ("EX-201" manufactured by Nagase Chemtex), 3 parts It was placed in a flask and dissolved at 100° C. under a flow of nitrogen. Then, 0.15 weight part of triphenylbutylphosphonium bromide which is an addition reaction catalyst of a hydroxyl group and an epoxy group was added, and the reaction product (polymer A) was obtained by carrying out addition polymerization reaction at 140 degreeC under nitrogen flow for 4 hours.

By NMR, it was confirmed that the addition polymerization reaction had progressed, and the reaction product (polymer A) was a structural unit in which a hydroxyl group derived from bisphenol F and an epoxy group of 1,6-hexanediol diglycidyl ether and bisphenol F-type epoxy resin were bonded. It was confirmed that it has in the main chain and has an epoxy group at both ends.

The weight average molecular weight of the reactant (polymer A) obtained by GPC was 28000, and the number average molecular weight was 8000.

Polymer B: both-terminal epoxy group rigid skeleton phenoxy resin, Mitsubishi Chemical Corporation "YX6900BH45", weight average molecular weight 16000

Thermosetting compound 1: Resorcinol type epoxy compound, "EX-201" manufactured by Nagase Chemtex

Thermosetting compound 2: Epoxy compound, "EXA-4850-150" manufactured by DIC, molecular weight 900, epoxy equivalent 450 g/eq

Thermosetting agent 1: Trimethylolpropane tris (3-mercaptopropinate), SC Yuki Chemical Co., Ltd. "TMMP"

Latent epoxy thermosetting agent 1: "FUJI Cure 7000" manufactured by T&K TOKA

Flux 1: Glutaric acid, manufactured by Wako Pure Chemical Industries, Ltd., melting point (activation temperature) 96°C

Method for producing solder particles 1 to 3:

Solder particles having anionic polymer 1: 200 g of a solder particle body, 40 g of adipic acid, and 70 g of acetone were weighed into a three-necked flask, followed by a dehydration condensation catalyst between the hydroxyl group on the surface of the solder particle body and the carboxyl group of adipic acid 0.3 g of dibutyltin oxide was added and reacted at 60°C for 4 hours. Thereafter, the solder particles were collected by filtration.

The recovered solder particles, 50 g of adipic acid, 200 g of toluene, and 0.3 g of para-toluenesulfonic acid were weighed in a three-necked flask, and reacted at 120°C for 3 hours while vacuuming and refluxing. At this time, using the Dean-Stark extraction apparatus, it was made to react, removing the water produced|generated by dehydration condensation.

Thereafter, the solder particles were collected by filtration, washed with hexane and dried. Thereafter, the obtained solder particles were pulverized with a ball mill, and then a sieve was selected so as to have a predetermined CV value.

(Measurement of Zeta Potential)

Further, the obtained solder particles were uniformly dispersed by adding 0.05 g of the solder particles having the anionic polymer 1 to 10 g of methanol and ultrasonicating to obtain a dispersion liquid. The zeta potential was measured by the electrophoresis measurement method using this dispersion liquid and further using "Delsamax PRO" manufactured by Beckman Coulter.

(weight average molecular weight of anionic polymer)

The weight average molecular weight of the anionic polymer 1 on the surface of the solder particles was determined by GPC by dissolving the solder using 0.1 N hydrochloric acid, then collecting the polymer by filtration.

(CV value of solder particles)

The CV value was measured with a laser diffraction type particle size distribution analyzer ("LA-920" manufactured by Horiba Seisakusho).

Solder particle 1 (SnBi solder particle, melting point 139° C., solder particle having anionic polymer 1 surface-treated using a solder particle body selected from “ST-3” manufactured by Mitsui Kinzoku Co., Ltd., average particle diameter 4 µm, CV value 7%, surface zeta potential: +0.65 mV, polymer molecular weight Mw=6500)

Solder particle 2 (SnBi solder particle, melting point 139°C, solder particle having anionic polymer 1 surface-treated using a solder particle body selected from "DS10" manufactured by Mitsui Kinzoku Co., Ltd., average particle diameter 13 µm, CV value 20 %, surface zeta potential: +0.48 mV, polymer molecular weight Mw=7000)

Solder particle 3 (SnBi solder particle, melting point 139°C, solder particle having anionic polymer 1 surface-treated using a solder particle body selected from "10-25" manufactured by Mitsui Kinzoku Co., Ltd., average particle diameter of 25 µm, CV value 15%, surface zeta potential: +0.4 mV, polymer molecular weight Mw=8000)

Solder particle 4 (SnBi solder particle, melting point 139° C., solder particle having anionic polymer 1 surface-treated using a solder particle body selected from “ST-3” manufactured by Mitsui Kinzoku Co., Ltd., average particle diameter 3 μm, CV value 7%, surface zeta potential: +0.65 mV, polymer molecular weight Mw=6500)

Electroconductive particle 1: A copper layer having a thickness of 1 µm is formed on the surface of a resin particle, and a solder layer (tin: bismuth = 43 wt%: 57 wt%) having a thickness of 3 µm is formed on the surface of the copper layer. conductive particles

The manufacturing method of the electroconductive particle 1 :

Divinylbenzene resin particles having an average particle diameter of 10 μm (“Micropearl SP-210” manufactured by Sekisui Chemical Co., Ltd.) were electroless nickel plated to form a base nickel plating layer having a thickness of 0.1 μm on the surface of the resin particles. . Then, the electrolytic copper plating of the resin particle with a base nickel plating layer was carried out, and the 1 micrometer-thick copper layer was formed. Further, electrolytic plating was performed using an electrolytic plating solution containing tin and bismuth to form a solder layer having a thickness of 3 mu m. In this way, a copper layer having a thickness of 1 µm is formed on the surface of the resin particles, and a solder layer (tin: bismuth = 43 wt%: 57 wt%) having a thickness of 3 µm is formed on the surface of the copper layer. Electroconductive particle 1 was produced.

Spacer 1 (average particle size 20 µm, CV value 5%, softening point 330°C, Sekisui Chemical Co., Ltd. crosslinked particles, divinylbenzene crosslinked particles, 10% K value 4400 N/mm ² , compression recovery rate 55%)

Spacer 2 (average particle size of 30 µm, CV value of 5%, softening point of 330°C, manufactured by Sekisui Chemical Co., Ltd., divinylbenzene crosslinked particles, 10% K value of 4200 N/mm ² , compression recovery rate of 54%)

Spacer 3 (average particle diameter of 50 µm, CV value of 5%, softening point of 330°C, manufactured by Sekisui Chemical Co., Ltd., divinylbenzene crosslinked particles, 10% K value of 4100 N/mm ² , compression recovery rate of 54%)

Phenoxy resin (“YP-50S” manufactured by Shin Nitetsu Sumikin Chemical Co., Ltd.)

(Examples 1 to 10)

(1) Preparation of anisotropic conductive paste

The component shown in following Table 1 was mix|blended by the compounding quantity shown in following Table 1, and the anisotropic electrically conductive paste was obtained.

(2) Preparation of first bonded structure (L/S = 50 µm/50 µm)

The glass epoxy board|substrate (FR-4 board|substrate) (1st connection object member) which has L/S 50 micrometers/50 micrometers, and the copper electrode pattern (copper electrode thickness 12 micrometers) of 3 mm electrode length on the upper surface was prepared. Furthermore, L/S prepared the flexible printed circuit board (2nd connection object member) which has on the lower surface 50 micrometers/50 micrometers, and the copper electrode pattern (thickness of copper electrode 12 micrometers) whose electrode length is 3 mm.

The overlapping area of the glass epoxy substrate and the flexible printed circuit board was 1.5 cm x 3 mm, and the number of connected electrodes was 75 pairs.

On the upper surface of the glass epoxy substrate, the anisotropic conductive paste immediately after production was applied by screen printing using a metal mask so as to have a thickness of 100 μm on the electrode of the glass epoxy substrate by screen printing to form an anisotropic conductive paste layer. Next, the said flexible printed circuit board was laminated|stacked on the upper surface of the anisotropic electrically conductive paste layer so that the electrodes might oppose. At this time, pressurization was not performed. The weight of the said flexible printed circuit board is added to the anisotropic electrically conductive paste layer. Then, the solder was melt|melted, heating so that the temperature of the anisotropic electrically conductive paste layer might become 190 degreeC, and the anisotropic electrically conductive paste layer was hardened at 190 degreeC for 10 second, and the 1st bonded structure was obtained.

(3) Production of the second bonded structure (L/S = 75 µm/75 µm)

The glass epoxy board|substrate (FR-4 board|substrate) (1st connection object member) which has L/S 75 micrometers/75 micrometers, and the copper electrode pattern (thickness of copper electrode 12 micrometers) whose electrode length is 3 mm on the upper surface was prepared. Furthermore, L/S prepared the flexible printed circuit board (2nd connection object member) which has on the lower surface the copper electrode pattern (thickness of a copper electrode 12 micrometers) of 75 micrometers/75 micrometers and electrode length 3mm.

Except having used the said glass epoxy board|substrate and flexible printed circuit board from which L/S differs, it carried out similarly to preparation of 1st bonded structure, and obtained the 2nd bonded structure.

(4) Preparation of a third bonded structure (L/S = 100 µm/100 µm)

The glass epoxy board|substrate (FR-4 board|substrate) (1st connection object member) which has a copper electrode pattern (thickness of copper electrode 12 micrometers) whose L/S is 100 micrometers / 100 micrometers and an electrode length of 3 mm on the upper surface was prepared. Moreover, L/S prepared the flexible printed circuit board (2nd connection object member) which has on the lower surface 100 micrometers/100 micrometers, and the copper electrode pattern (thickness of copper electrode 12 micrometers) whose electrode length is 3 mm.

Except having used the said glass epoxy board|substrate and flexible printed circuit board from which L/S differs, it carried out similarly to preparation of 1st bonded structure, and obtained 3rd bonded structure.

(Comparative Example 1)

The component shown in following Table 1 was mix|blended by the compounding quantity shown in following Table 1, and the anisotropic electrically conductive paste was obtained. Except having used the obtained anisotropic electrically conductive paste, it carried out similarly to Example 1, and obtained the 1st, 2nd, and 3rd bonded structure.

(Comparative Example 2)

The component shown in following Table 1 was mix|blended by the compounding quantity shown in following Table 1, and the anisotropic electrically conductive paste was obtained. Except having used the obtained anisotropic electrically conductive paste, and having applied the pressure of 1 MPa at the time of heating, it carried out similarly to Example 1, and obtained the 1st, 2nd, and 3rd bonded structure.

(Comparative Example 3)

A phenoxy resin ("YP-50S" manufactured by Nippon-Sumikin Chemical Co., Ltd.) was dissolved in methyl ethyl ketone (MEK) so that the solid content was 50% by weight to obtain a solution. The components other than the phenoxy resin shown in Table 1 below were blended with the blending amount shown in Table 1 below, and the total amount of the solution, stirred for 5 minutes at 2000 rpm using a planetary stirrer, and then dried using a bar coater. It coated on the mold release PET (polyethylene terephthalate) film so that the thickness afterward might be set to 30 micrometers. By vacuum-drying at room temperature, the anisotropic conductive film was obtained by removing MEK. Except having used the anisotropic conductive film, it carried out similarly to Example 1, and obtained the 1st, 2nd, and 3rd bonded structure.

(Comparative Examples 4 and 5)

The component shown in following Table 1 was mix|blended by the compounding quantity shown in following Table 1, and the anisotropic electrically conductive paste was obtained. Except having used the obtained anisotropic electrically conductive paste, it carried out similarly to Example 1, and obtained the 1st, 2nd, and 3rd bonded structure.

(evaluation)

(1) Viscosity

The viscosity (η25) in 25 degreeC of anisotropic electrically conductive paste was measured on 25 degreeC and conditions of 5 rpm using the E-type viscometer (made by Toki Sangyo).

(2) Thickness of solder part

Cross-sectional observation of the obtained bonded structure evaluated the thickness of the solder part in which the upper and lower electrodes are located.

(3) Self-alignment property

Production of the 3rd bonded structure WHEREIN: The amount of shift|offset|difference between the electrode of a glass epoxy board|substrate and the electrode of a flexible printed circuit board is 25 micrometers (for 4th bonded structure), 50 micrometers (for 5th bonded structure), 75 micrometers ( 6th bonded structure) and 90 micrometers (for 7th bonded structures), except having overlapped, it carried out similarly, and obtained 4th - 7th bonded structure.

The amount of shift|offset|difference between the electrode of the glass epoxy board|substrate of the obtained 4th - 7th bonded structure, and the electrode of a flexible printed circuit board was measured. 25 4th - 7th bonded structures were produced, the shift|offset|difference amount of the upper and lower electrodes was measured with the electrode located at the both ends of each bonded structure, and the average value of the measured value was calculated|required. Self-alignment property was judged on the following reference|standard.

○○: The average value of the shift amount is less than 10 μm

(circle): The average value of the shift|offset|difference amount is 10 micrometers or more and less than 25 micrometers

(triangle|delta): The average value of the shift|offset|difference amount is 25 micrometers or more, and less than 50 micrometers.

x: the average value of the shift|offset|difference amount is 50 micrometers or more

(4) Accuracy of placement of solder on electrodes 1

In the obtained 1st, 2nd, 3rd connection structure, when the mutually opposing part of a 1st electrode and a 2nd electrode is seen in the lamination direction of a 1st electrode, a connection part, and a 2nd electrode, a 1st electrode and a 2nd electrode The ratio X of the area in which the solder part in the connection part is arrange|positioned in 100% of the area of the mutually opposing part of an electrode was evaluated. The placement accuracy of the solder on the electrode of 1 was determined on the basis of the following criteria.

[Criterion of Solder Arrangement Accuracy 1 on Electrodes]

○○: Ratio X is 70% or more

○: Ratio X is 60% or more and less than 70%

△: Ratio X is 50% or more and less than 60%

x: ratio X is less than 50%

(5) Accuracy of placement of solder on electrodes 2

In the obtained 1st, 2nd, and 3rd bonded structure, when the mutually opposing part of a 1st electrode and a 2nd electrode is seen in the direction orthogonal to the lamination direction of a 1st electrode, a connection part, and a 2nd electrode, in the connection part The ratio Y of the solder part in the connection part arrange|positioned at the mutually opposing part of the 1st electrode and the 2nd electrode among 100% of solder parts was evaluated. The placement accuracy 2 of the solder on the electrode was determined on the basis of the following criteria.

[Criterion of Solder Arrangement Accuracy 2 on Electrodes]

○○: ratio Y is 99% or more

○: ratio Y is 90% or more and less than 99%

Δ: ratio Y is 70% or more and less than 90%

x: ratio Y is less than 70%

(6) Reliability of conduction between upper and lower electrodes

In the obtained 1st, 2nd, 3rd bonded structure (n=15 pieces), the connection resistance per 1 connection location between an upper and lower electrode was respectively measured by the 4-probe method. The average value of connection resistance was computed. Further, in the relationship of voltage = current x resistance, the connection resistance can be obtained by measuring the voltage when a constant current is passed. Conduction reliability was judged according to the following criteria.

[Criteria for judgment of continuity reliability]

○○: The average value of the connection resistance is 50 mΩ or less

○: The average value of the connection resistance exceeds 50 mΩ and 70 mΩ or less

(triangle|delta): The average value of connection resistance exceeds 70 mΩ, and 100 mΩ or less

×: The average value of the connection resistance exceeds 100 mΩ, or a poor connection occurs

(7) Insulation reliability between adjacent electrodes

In the obtained 1st, 2nd, 3rd bonded structure (n=15 pieces), after leaving it to stand for 100 hours in the atmosphere of 85 degreeC and 85% of humidity, 5 V is applied between adjacent electrodes, and the resistance value is set at 25 places. measured. Insulation reliability was judged according to the following criteria.

[Criteria for determining insulation reliability]

○○: The average value of the connection resistance is 10 ⁷ Ω or more

○: The average value of the connection resistance is 10 ⁶ Ω or more and less than 10 ⁷ Ω

△: The average value of the connection resistance is 10 ⁵ Ω or more and less than 10 ⁶ Ω

×: The average value of the connection resistance is less than 10 ⁵ Ω

(8) Position misalignment between the upper and lower electrodes

In the obtained 1st, 2nd, and 3rd connection structure, when the mutually opposing part of a 1st electrode and a 2nd electrode is seen in the lamination direction of a 1st electrode, a connection part, and a 2nd electrode, the center line of the 1st electrode and Whether the center lines of the second electrode are aligned, and the distance of the misalignment were evaluated. The position shift between the upper and lower electrodes was determined on the basis of the following criteria.

[Criteria for judging position shift between upper and lower electrodes]

○○: Position shift is less than 15㎛

○: Position shift is 15 μm or more and less than 25 μm

(triangle|delta): position shift is 25 micrometers or more, and less than 40 micrometers

x: position shift is 40 µm or more

Details and results are shown in Tables 1 and 2 below.

It replaced with a flexible printed circuit board, and also when a resin film, a flexible flat cable, and a rigid flexible board were used, the similar tendency appeared.

1, 1X, 1Y: Connection structure 2, 2Y: 1st connection object member
2a: 1st electrode 2y: 1st convex part
3, 3Y: 2nd connection object member 3a: 2nd electrode
3y: second convex part 4, 4X, 4Y: connection part
4A, 4XA, 4YA: Solder part 4B, 4XB, 4YB: Hardened part
5, 5X, 5Y: spacer 11: conductive paste
11A: solder particles 11B: thermosetting component

Claims (15)

A conductive paste used for connecting a first connection object member having a first electrode on the surface and a second connection object member having a second electrode on the surface, and electrically connecting the first electrode and the second electrode,
a thermosetting component, a plurality of solder particles, and a plurality of spacers having a melting point of 250° C. or higher;
The conductive paste is heated above the melting point of the solder particles and above the curing temperature of the thermosetting component, and when the first electrode and the second electrode are electrically connected, the spacer is not melted and the plurality of the It is used by agglomerating solder particles and integrating them,
An average particle diameter of the spacers is larger than an average particle diameter of the solder particles, and a ratio of the average particle diameter of the spacers to the average particle diameter of the solder particles is 10 or less. The conductive paste according to claim 1, wherein the spacers are insulating particles. The conductive paste according to claim 1 or 2, wherein the conductive paste is used so that the spacer is in contact with both the first connection object member and the second connection object member. The electrically conductive paste according to claim 1 or 2, wherein the ratio of the average particle diameter of the spacer to the average particle diameter of the solder particles is 1.1 or more and 10 or less. The electrically conductive paste of Claim 1 or 2 whose content of the said spacer is 0.1 weight% or more and 10 weight% or less. The electrically conductive paste of Claim 1 or 2 whose average particle diameter of the said solder particle is 1 micrometer or more and 40 micrometers or less. The electrically conductive paste of Claim 1 or 2 whose content of the said solder particle is 10 weight% or more and 80 weight% or less. The electrically conductive paste according to claim 1 or 2, wherein the ratio of the content in the weight% unit of the solder particles to the content in the weight% unit of the spacer is 2 or more and 100 or less. a first connection object member having at least one first electrode on its surface;
a second connection object member having at least one second electrode on its surface;
A connection portion connecting the first connection object member and the second connection object member is provided;
The material of the said connection part is the electrically conductive paste of Claim 1 or 2,
the first electrode and the second electrode are electrically connected to each other by a solder portion in the connection portion;
The connection structure in which the said spacer is contacting both the said 1st connection object member and the said 2nd connection object member. The connection structure of Claim 9 whose said 2nd connection object member is a resin film, a flexible printed circuit board, a flexible flat cable, or a rigid flexible board|substrate. A step of disposing the conductive paste on the surface of a first connection object member having at least one first electrode on the surface using the conductive paste according to claim 1 or 2;
a second connection object member having at least one second electrode on the surface of the conductive paste opposite to the first connection object member side is disposed so that the first electrode and the second electrode face each other process and
By heating the conductive paste above the melting point of the solder particles and above the curing temperature of the thermosetting component, a connection portion connecting the first connection object member and the second connection object member is formed with the conductive paste, further comprising a step of electrically connecting the first electrode and the second electrode with a solder portion in the connection portion, and bringing the spacer into contact with both the first connection object member and the second connection object member; ,
A method for manufacturing a bonded structure in which, when electrically connecting the first electrode and the second electrode, the spacer is not melted, and a plurality of the solder particles are aggregated and integrated. The manufacturing of the bonded structure according to claim 11, wherein in the step of arranging the second connection object member and the step of forming the connection portion, the weight of the second connection object member is applied to the conductive paste without applying pressure. Way. The manufacturing method of the bonded structure of Claim 11 whose said 2nd connection object member is a resin film, a flexible printed circuit board, a flexible flat cable, or a rigid flexible board|substrate. delete delete

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