KR102410173B1 - Conductive paste, production method for conductive paste, connection structure, and production method for connection structure - Google Patents

Abstract

The electrically conductive paste which can improve coating property, can arrange|position electroconductive particle efficiently on an electrode, and can improve the conduction|electrical_connection reliability between electrodes is provided. The conductive paste according to the present invention includes a thermosetting component and a plurality of conductive particles, wherein the thermosetting component contains a thermosetting compound solid at 25° C. and a thermosetting agent, and in the conductive paste, a thermosetting compound solid at 25° C. It is dispersed in this particulate form.

Description

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

This invention relates to the manufacturing method of the electrically conductive paste containing electroconductive particle, and an electrically conductive paste. 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, in order to obtain various bonded structures, for example, connection of a flexible printed circuit board and a glass substrate (FOG (Film on Glass)), a semiconductor chip and a flexible printed circuit board connection (COF (Chip on Film)), It is used for the connection of a semiconductor chip and a glass substrate (COG (Chip on Glass)), and the connection (FOB (Film on Board)) of a flexible printed circuit board and a glass epoxy board|substrate.

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, solder powder, and a curing agent, wherein the solder powder and the curing agent are present in the resin layer. 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 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 below, 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 are opposed to 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 to a predetermined temperature and adhered. Thereby, a bonded structure is obtained.

In addition, the following Patent Document 2 discloses an anisotropic conductive material comprising (A) a silica filler having an average particle diameter of 3 to 100 nm subjected to hydrophobic treatment, (B) an adhesive component, and (C) conductive particles. . In patent document 2, the quantity of the said silica filler is 10-60 mass % with respect to the total amount of the said adhesive agent component.

In Patent Document 3 below, (1) an epoxy resin having an average of 1.2 or more epoxy groups in one molecule, (2) rubber-like polymer particles having a softening point temperature of 0° C. or less and a primary particle diameter of 5 μm or less, (3) An anisotropic conductive material comprising a thermally active latent epoxy curing agent and (4) high softening point polymer fine particles having a softening point temperature of 50° C. or higher and a primary particle diameter of 2 μm or less is disclosed.

WO2008/023452A1 Japanese Patent Laid-Open No. 2011-233633 Japanese Patent Laid-Open No. 2000-345010

The adhesive tape of patent document 1 is a film form, and is not paste form. For this reason, it is difficult to efficiently arrange the solder powder on the electrode (line). For example, in the adhesive tape of 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.

Also, even in the anisotropic conductive paste containing solder powder, the solder powder may not be efficiently disposed on the electrode (line). Moreover, in the anisotropic electrically-conductive material as described in patent document 2, when coating by screen printing etc., the coatability may be low.

In addition, when the viscosity of the anisotropic conductive paste containing solder powder is made low, the solder powder tends to move onto the electrode (line). However, when the viscosity of the anisotropic electrically conductive paste is lowered, the thickness of the anisotropic electrically conductive paste layer after coating becomes thin, or the anisotropic electrically conductive paste flows excessively, which tends to be arranged in an unintended area.

Further, in Patent Document 3, as the above (1) epoxy resin, (1-1) a liquid epoxy resin in a temperature range of 0 to 50° C., and (1-2) a solid epoxy resin in a temperature range of 0 to 50° C. The use of mixtures of resins is described. However, in Patent Document 3, for example, in the Examples, "Epiclon EP-1004", which is a bisphenol A type epoxy resin, is dissolved with 1,6-hexanediol diglycidyl ether, so that the anisotropic conductive paste is used. In the inside, only the specific example in which the solid epoxy resin is melt|dissolving is shown. As described above, even if it is a solid epoxy resin at 25°C alone, in the anisotropic conductive paste, the epoxy resin is not limited to a solid state, and the epoxy resin is generally used in a dissolved state.

The objective of this invention is providing the electrically conductive paste which can improve coating property, and can arrange|position electroconductive particle efficiently on an electrode, and can improve the conduction|electrical_connection reliability between electrodes, and the manufacturing method of an electrically conductive paste. 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 thermosetting component and a plurality of conductive particles are included, wherein the thermosetting component contains a thermosetting compound that is solid at 25°C, and a thermosetting agent, and in a conductive paste, a thermosetting substance that is solid at 25°C A conductive paste in which a compound is dispersed in a particulate form is provided.

On the specific situation with the electrically conductive paste which concerns on this invention, the said electrically conductive paste contains the thermosetting compound which is liquid at 25 degreeC.

On the specific situation with the electrically conductive paste which concerns on this invention, the said thermosetting compound solid at 25 degreeC is a solid thermosetting epoxy compound at 25 degreeC.

In a specific aspect of the conductive paste according to the present invention, the thermosetting compound solid at 25°C has a melting point different from that of the first thermosetting compound solid at 25°C and the first thermosetting compound, and is solid at 25°C and a second thermosetting compound.

It is preferable that the said electroconductive particle has a solder on an electroconductive outer surface, and it is more preferable that it is a solder particle.

In the specific situation of the electrically conductive paste which concerns on this invention, melting|fusing point of the solder in the said electroconductive particle at -5 degreeC and the viscosity in 0.5 rpm, melting|fusing point of the solder in the said electroconductive particle at -5 degreeC, and the viscosity at 5 rpm The ratio to is 1 or more and 2 or less.

On the specific situation with the electrically conductive paste which concerns on this invention, the particle diameter of the said thermosetting compound which is particulate form is 1 micrometer or more and 40 micrometers or less.

In a specific situation of the conductive paste according to the present invention, the ratio of the viscosity at 25°C and 0.5 rpm to the viscosity at 25°C and 5 rpm is 2.5 or more and 7 or less, and in another specific situation, the viscosity at 25°C and 0.5 rpm The ratio of the viscosity to the viscosity at 25° C. and 5 rpm is 4 or more and 7 or less.

In certain specific aspects of the conductive paste according to the present invention, the conductive paste includes a flux.

In a specific aspect of the conductive paste according to the present invention, the conductive paste does not contain a filler or contains a filler in an amount of 1% by weight or less in 100% by weight of the conductive paste.

According to a broad aspect of the present invention, there is provided a method for producing the conductive paste described above, wherein a mixture is obtained by mixing a thermosetting compound solid at 25° C., a thermosetting component containing a thermosetting agent, and a plurality of conductive particles, and then the mixture, By heating at or above the melting point of the solid thermosetting compound at 25° C. and below the curing temperature of the thermosetting component, the solid thermosetting compound at 25° C. is melted and then solidified. A mixture containing a thermosetting component containing a particulate and solid thermosetting compound and a thermosetting agent, and a plurality of conductive particles after obtaining a conductive paste or a thermosetting compound solid at 25° C. Also, there is provided a method for producing an electrically conductive paste to obtain an electrically conductive paste in which a solid thermosetting compound is dispersed in a particulate form at 25°C.

In 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 and the first connection object member A connection portion for connecting two connection object members is provided, wherein the connection portion is formed of the conductive paste described above, and the first electrode and the second electrode are electrically connected by the conductive particles in the connection portion, A connection structure 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; a step of arranging 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 solid thermosetting compound at °C 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 by the conductive paste And further, the manufacturing method of a bonded structure provided with the process of electrically connecting the said 1st electrode and the said 2nd electrode with the said electroconductive particle in the said connection part is provided.

In the specific situation 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, pressurization is not performed, but the said 2nd connection object member is applied to the said electrically conductive paste. 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 includes a thermosetting component and a plurality of conductive particles, wherein the thermosetting component contains a thermosetting compound and a thermosetting agent that are solid at 25° C., and in the conductive paste according to the present invention, the 25° C. Since the solid thermosetting compound is dispersed in particulate form, the coating property of the conductive paste can be improved. Moreover, when between electrodes is electrically connected using the electrically conductive paste which concerns on this invention, electroconductive particle can be efficiently arrange|positioned on an electrode, and the conduction|electrical_connection reliability between electrodes can be improved.

BRIEF DESCRIPTION OF THE DRAWINGS It is a partially cut-out front cross-sectional view 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.
Fig. 3 is a partially cut-out front cross-sectional view showing a modified example of a bonded structure.
It is sectional drawing which shows typically the electroconductive particle which can be used for the electrically conductive paste which concerns on one Embodiment of this invention.
It is sectional drawing which shows the modified example of electroconductive particle.
It is sectional drawing which shows the other modified example of electroconductive particle.
Fig. 7 is an image showing a thermosetting compound dispersed in a particulate form in a conductive paste according to an embodiment of the present invention.

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

In the electrically conductive paste which concerns on this invention, a thermosetting component and some electroconductive particle are included. In the electrically conductive paste which concerns on this invention, the said thermosetting component contains the thermosetting compound and thermosetting agent which are solid at 25 degreeC. In the conductive paste according to the present invention, the thermosetting compound solid at 25° C. is dispersed in the form of particles.

In the electrically conductive paste which concerns on this invention, since the said structure is employ|adopted, coating workability can be improved. The electrically conductive paste which concerns on this invention can be coated favorably by coating methods, such as a dispenser and screen printing. When the viscosity of an anisotropic electrically conductive paste is made low, electroconductive particle will become easy to move on an electrode (line). In an electrically conductive paste, that the thermosetting compound solid at 25 degreeC is disperse|distributed in particulate form contributes greatly to improving the coatability. For example, the viscosity of the electrically conductive paste is appropriately increased, and the thixotropic properties of the electrically conductive paste are appropriately expressed. It becomes difficult to be placed in an unintended area. On the other hand, in order to make the viscosity of an electrically conductive paste high, when a filler is mix|blended in a predetermined amount, a filler will prevent the movement to the electrode top of electroconductive particle. On the other hand, the thermosetting compound which is solid at the said 25 degreeC is hard to prevent the movement to the electrode top of electroconductive particle compared with a filler. In particular, when a thermosetting compound becomes liquid at the time of movement to the electrode top of electroconductive particle, the thermosetting compound which became liquid does not prevent the movement to the electrode top of electroconductive particle.

In particular, in the electrically conductive paste which concerns on this invention, since the said structure is employ|adopted, when it electrically connects between electrodes, several electroconductive particle is easy to collect between a 1st electrode and a 2nd electrode, and several electroconductive particle is an electrode. It can be arranged efficiently on (line). Moreover, it is hard to arrange|position in the area|region (space) in which a some electroconductive particle is not formed with an electrode, and it can reduce the quantity of electroconductive particle arrange|positioned in the area|region in which an electrode is not formed considerably. Accordingly, the conduction reliability between the first electrode and the second electrode can be improved. Moreover, the electrical connection between the electrodes adjacent to the horizontal direction which should not be connected can be prevented, and insulation reliability can be improved. It is thought that it is because it is difficult for the thermosetting compound solid at said 25 degreeC to prevent the movement to the electrode top of electroconductive particle compared with a filler that such an effect is acquired.

In the electrically conductive paste which concerns on this invention, the improvement effect of coatability and the improvement effect of the conduction|electrical_connection reliability between electrodes achieved by the efficient movement to the electrode top of electroconductive particle can be made compatible and it can be obtained. Moreover, in the electrically conductive paste which concerns on this invention, when electroconductive particle has a solder on an electrically conductive outer surface, the structure of a particulate-form thermosetting compound and the structure of electroconductive particle which are easy to move in an electrically conductive paste rise, The effect of this invention to be more effective. Moreover, in the electrically conductive paste which concerns on this invention, when electroconductive particle is a solder particle, the structure of a particulate-form thermosetting compound and the structure of electroconductive particle which especially easily move in an electrically conductive paste rise, and the effect of this invention more effectively exerted.

The manufacturing method of the electrically conductive paste which concerns on this invention is (1) mixing the thermosetting component containing a thermosetting compound and a thermosetting agent solid at 25 degreeC, and some electroconductive particle, and obtaining a mixture, Then, the said mixture is said 25 degreeC By heating the solid thermosetting compound above the melting point of the solid thermosetting compound and below the curing temperature of the thermosetting component to melt the solid thermosetting compound at 25 ° C. and then solidify it, the thermosetting compound solid at 25 ° C. Conductivity in which the solid thermosetting compound is dispersed in the form of particles After obtaining a paste or (2) making a thermosetting compound solid at 25 ° C into particulate form, the thermosetting compound which is particulate and solid at 25 ° C and a thermosetting component containing a thermosetting agent, and a mixture of a plurality of conductive particles; Furthermore, the electrically conductive paste in which the thermosetting thermosetting epoxy compound which is solid at the said 25 degreeC is disperse|distributed in particulate form is obtained. According to the manufacturing method of the electrically conductive paste concerning this invention, the electrically conductive paste which concerns on this invention can be obtained easily. In the case of the method (2) above, when the thermosetting compound solid at 25°C is in the form of particles, the thermosetting agent may be already mixed, or the thermosetting compound liquid at 25°C to be blended may already be mixed as needed. When making a solid thermosetting compound at 25 degreeC into particulate form, it is preferable that electroconductive particle is not mixed.

Moreover, it is preferable to have a solder on an electroconductive outer surface, and, as for the said electroconductive particle contained in the said electrically conductive paste, it is more preferable that it is a solder particle. If such preferable electroconductive particle is used, electroconductive particle can be arrange|positioned on an electrode still more efficiently.

The electrically conductive paste which concerns on this invention can be used suitably for the manufacturing method of the following bonded structure which concerns on this invention.

In the manufacturing method of the bonded structure which concerns on this invention, an electrically conductive paste, a 1st connection object member, and a 2nd connection object member are used. The electrically-conductive material used with the manufacturing method of the bonded structure which concerns on this invention is not an electrically-conductive film, but an electrically-conductive paste. The said electrically conductive paste contains several electroconductive particle and a thermosetting component. The said 1st connection object member has at least 1 1st electrode on the surface. The said 2nd connection object member has at least 1 2nd electrode on the surface.

A method for manufacturing a bonded structure according to the present invention includes the steps of disposing the conductive paste on the surface of the first connection object member, the conductive paste on a surface opposite to the first connection object member side; disposing the second connection target member so that the first electrode and the second electrode face each other; and heating the conductive paste above the melting point of the thermosetting compound solid at 25° C. and above the curing temperature of the thermosetting component. By doing so, the connection part which is connecting the said 1st connection object member and the said 2nd connection object member is formed with the said electrically conductive paste, and the said 1st electrode and the said 2nd electrode are electrically connected with the electroconductive particle in the said connection part. A step of connecting is provided.

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. It is preferable to lose 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 said electrically conductive paste is pressurizing pressure exceeding the force of the weight of the said 2nd connection object member. Preferably, no silver is added.

In the manufacturing method of the bonded structure which concerns on this invention, since the said structure is employ|adopted, a some electroconductive particle is easy to gather between a 1st electrode and a 2nd electrode, and a some electroconductive particle is arrange|positioned on an electrode (line) efficiently can Moreover, it is hard to arrange|position in the area|region (space) in which a some electroconductive particle is not formed with an electrode, and it can reduce the quantity of electroconductive particle arrange|positioned in the area|region in which an electrode is not formed considerably. Accordingly, the conduction reliability between the first electrode and the second electrode can be improved. Moreover, the electrical connection between the electrodes adjacent to the horizontal direction which should not be connected can be prevented, and insulation reliability can be improved.

Thus, in order to arrange|position several electroconductive particle efficiently on an electrode, and to reduce the quantity of electroconductive particle arrange|positioned in the area|region where an electrode is not formed considerably, it is necessary to use the electrically conductive paste instead of an electrically conductive film , we found out.

Further, in the step of arranging 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, the electrode before the connection portion is formed The electroconductive particle arrange|positioned in this non-formed area|region (space) becomes still more easy to gather between a 1st electrode and a 2nd electrode, and it is also possible to arrange|position several electroconductive particle efficiently on an electrode (line), We found out. In the present invention, a combination of a configuration in which a conductive paste rather than a conductive film is used and a configuration in which the weight of the second connection object member is applied to the conductive paste without applying pressure is employed in combination, It has a great meaning because the effect of the invention 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 at the time of bonding. From a viewpoint, for example, it is described that it is 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, the adhesive tape It is described that a predetermined pressure may be applied to the . In WO2008/023452A1, it is described that the pressure to be intentionally applied to the adhesive tape may be 0 MPa, but the difference between the effect when a pressure exceeding 0 MPa is applied and when it is set to 0 MPa is not described at all.

In addition, when an electrically conductive paste instead of an electrically conductive film is used, it is also possible to adjust the thickness of a connection part suitably 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 different thickness must be prepared, or the conductive film of predetermined thickness must be prepared.

In the manufacturing method of the bonded structure which concerns on this invention, when the said electroconductive particle is electroconductive particle which has solder on the electrically conductive outer surface, or when it is a solder particle, when forming the said connection part, it is preferable to heat above the melting|fusing point of solder. do. In this case, the first electrode and the second electrode are more firmly joined by the solidified solder portion after melting. As a result, the conduction reliability between the electrodes is further improved.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is made clear by describing specific embodiment and Example of this invention, referring drawings.

First, the bonded structure obtained by using the electrically conductive paste which concerns on one Embodiment of this invention in FIG. 1 is shown typically by the partial cut-out front sectional drawing.

The connection structure 1 shown in FIG. 1 is 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 connection part 4 is formed with the electrically conductive paste containing a thermosetting component and some electroconductive particle. In this electrically conductive paste, the said thermosetting component contains the thermosetting compound which is solid at 25 degreeC, and a thermosetting agent, In the said electrically conductive paste, the said thermosetting compound solid at 25 degreeC is disperse|distributed in particulate form. In this embodiment, solder particle is used as said electroconductive particle.

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

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 does not exist. 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.

As shown in Fig. 1, in the bonded structure 1, after a plurality of solder particles are melted, the melt of the solder particles spreads on the surface of the electrode and then solidifies to form a solder portion 4A. 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 of using conductive particles whose conductive outer surface is a metal such as nickel, gold, or copper. 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. In addition, the electrically conductive paste may contain the flux. Generally, the flux contained in the electrically conductive paste is gradually deactivated 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 modified example 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 and a cured product portion 4XB. Like the connection structure 1X, most of the solder portion 4XA is located in the regions facing the first and second electrodes 2a and 3a, and a part of the solder portion 4XA is the first and second You may protrude laterally from the area|region which opposes 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. . In addition, in this embodiment, although the amount of the solder spaced apart from the solder part can be reduced, the solder spaced apart from the 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 . If the usage-amount of solder particle is increased, it will become easy to obtain the bonded structure 1X.

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 conductive paste 11 containing a thermosetting component 11B and a plurality of solder particles 11A. is placed (first step). A conductive paste 11 is disposed on the surface of the first connection object member 2 on which the first electrode 2a is provided. After the conductive paste 11 is disposed, the solder particles 11A are disposed both on the first electrode 2a (line) and on 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, Discharge by a dispenser, screen printing, discharge by an inkjet apparatus, etc. are mentioned. Especially, screen printing is preferable. By using the conductive paste according to the present invention, the coating property by screen printing is considerably improved, and even if screen printing is performed, the conductive paste layer can be formed to a predetermined thickness, and excessive spreading of the conductive paste is suppressed, and the conductive paste is electrically conductive. It becomes difficult for the paste to be placed in an unintended area.

Moreover, the 2nd connection object member 3 which has the 2nd electrode 3a on the surface (lower surface) is prepared. Next, as shown in FIG. 2B , in the conductive paste 11 on the surface of the first connection object member 2 , the conductive paste 11 is different from the first connection object member 2 side. 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 electrically conductive paste 11 is heated above the melting|fusing point of the thermosetting compound which is solid at 25 degreeC, and the hardening temperature of the thermosetting component 11B or more (3rd process). That is, the electrically conductive paste 11 is heated above the temperature lower than the melting|fusing point of a solid thermosetting compound at 25 degreeC, and the hardening temperature of the thermosetting component 11B. Preferably, the conductive paste 11 is heated above the melting point of the solder, that is, above the melting point of the solder particles 11A. During 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, the solder particles 11A are effectively collected between the first electrode 2a and the second electrode 3a. 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. do. 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 formed by thermosetting the thermosetting component 11B. is formed When the solder particles 3 move rapidly, the movement of the solder particles 3 not located between the first electrode 2a and the second electrode 3a starts, and then the first electrode 2a and the second electrode 3a. It is not necessary to keep the temperature constant until the movement of the solder particles 3 is completed between (3a).

In addition, you may provide a preliminary heating process throughout the 3rd process. In this preheating process, in a state in which the weight of the second connection object member 3 is applied to the conductive paste 11, at a temperature equal to or higher than the melting temperature of the solder, and at a temperature at which the thermosetting component 11B does not substantially thermoset, 5 It refers to the process of performing heating in seconds to 60 seconds. By providing this step, the action of the solder particles to collect between the first electrode and the second electrode is further increased, and voids that may occur between the first connection object member and the second connection object member can be suppressed. have.

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. Moreover, in at least one of the said 2nd process and the said 3rd process, when pressurizing, the effect|action which the solder particle|grains tend to collect between the 1st electrode and the 2nd electrode is inhibited. This was discovered by the present inventors.

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 obtained 1st connection object member 2, the electrically conductive paste 11, and the 2nd connection object member 3 is moved to a heating part, and the said 3rd process is performed, also be 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 preferably not less than the melting point of the solid thermosetting compound at 25° C. and not less than the curing temperature of the thermosetting component 11B, and preferably not less than the melting point of the solder and not less than the curing temperature of the thermosetting component. The heating temperature is preferably 130°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.

The temperature of the preheating step is preferably 100°C or higher, more preferably 120°C or higher, still more preferably 140°C or higher, preferably lower than 160°C, and more preferably 150°C or lower.

Moreover, the said 1st connection object member just needs to have at least 1 1st electrode. It is preferable that the said 1st connection object member has a some 1st electrode. The said 2nd connection object member just needs to have at least 1 2nd electrode. It is preferable that the said 2nd connection object member has a some 2nd electrode.

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, capacitors and diodes, and resin films, printed circuit boards, flexible printed circuit boards, flexible flat cables, rigid flexible boards, glass epoxy boards, and glass. Electronic components, such as circuit boards, such as a 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 in 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 high flexibility and have the property of being comparatively lightweight. When a conductive film is used for the connection of such a connection object member, there exists a tendency for electroconductive particle to collect on an electrode easily. On the other hand, since the conductive paste according to the present invention is used, even if a resin film, a flexible printed circuit board, a flexible flat cable, or a rigid flexible substrate is used, the conductive particles can be efficiently collected on the electrode, and the conduction reliability between the electrodes can be raised sufficiently. In the case of using a resin film, a flexible printed circuit board, a flexible flat cable, or a rigid flexible board, the effect of improving the conduction reliability between the electrodes by not applying pressure is more effective than when other connection object members such as a semiconductor chip are used. obtained more effectively.

Metal electrodes, such as a gold electrode, a nickel electrode, a tin electrode, an aluminum electrode, a copper electrode, a silver electrode, a molybdenum 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 or a flexible flat cable, 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. In addition, 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. Sn, Al, Ga, etc. are mentioned as said trivalent metal element.

The distance D1 of the connection part at the position where the first electrode and the second electrode are opposed is preferably 3 µm or more, more preferably 10 µm or more, preferably 100 µm or less, and more preferably 75 µm or more. μm or less. The connection reliability between a connection part and a connection object member as the said distance D1 is more than the said minimum becomes still higher. When the said distance D1 is below the said upper limit, it becomes easy to gather on an electrode still more easily electroconductive particle at the time of formation of a connection part, and the conduction|electrical_connection reliability between electrodes becomes still higher.

In the electrically conductive paste, the particle diameter of the thermosetting compound solid at 25°C in the particulate form is preferably 0.1 µm or more, more preferably 1 µm or more, preferably 40 µm or less, more preferably 30 µm or less, More preferably, it is 20 micrometers or less, Especially preferably, it is 10 micrometers or less.

The particle diameter of the thermosetting compound which is solid at 25 degreeC which is particulate form shows a number average particle diameter. The particle diameter of the thermosetting compound that is solid at 25° C. in the particulate form is, for example, 50 pieces of thermosetting compound that are solid at 25° C., which is a particulate form, is observed with an electron microscope or an optical microscope, and the average value is calculated.

The viscosity η1 at 25°C and 0.5 rpm 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, preferably 800 Pa·s or more. Hereinafter, more preferably, it is 600 Pa.s or less, More preferably, it is 500 Pa.s or less. The coating property of an electrically conductive paste and arrangement|positioning precision of electroconductive particle become it still higher that the said viscosity (eta)1 is more than the said minimum and below the said upper limit.

The viscosity η2 at 25°C and 5 rpm of the conductive paste is preferably 1 Pa·s or more, preferably 100 Pa·s or less. The coating property of an electrically conductive paste and arrangement|positioning precision of electroconductive particle become it still higher that the said viscosity (eta)2 is more than the said minimum and below the said upper limit.

The ratio (η1/η2) of the viscosity η1 at 25°C and 0.5 rpm to the viscosity η2 at 25°C and 5 rpm (η1/η2) is preferably 1 or more, more preferably 2.5 or more, still more preferably 4 or more, and preferably Preferably it is 7 or less, More preferably, it is 6 or less, More preferably, it is 5 or less. When the said ratio (η1/η2) is more than the said minimum and below the said upper limit, the coating property of an electrically conductive paste and arrangement|positioning precision of electroconductive particle become still higher, and the conduction|electrical_connection reliability between electrodes becomes high effectively.

When electroconductive particle has a solder on an electroconductive outer surface, let melting|fusing point of the solder in electroconductive particle be T degreeC. The ratio (η1'/η2') of the viscosity η1' at (T-5)°C and 0.5 rpm to the viscosity η2′ at (T-5)°C and 5 rpm is preferably 1 or more, preferably less than 2 When the said ratio (η1'/η2') is more than the said minimum and below the said upper limit, the arrangement|positioning precision of electroconductive particle becomes still higher, and the conduction|electrical_connection reliability between electrodes becomes high effectively.

The said viscosity can be suitably adjusted to the kind of compounding component, the compounding quantity of a compounding component, and especially the dispersed state of the thermosetting compound which is solid at 25 degreeC.

The viscosity is, for example, using an E-type viscometer (manufactured by Toki Sangyo), etc., under conditions of 25°C and 5rpm, 25°C and 0.5rpm, (T-5)°C and 5rpm and (T-5) It can be measured under the conditions of °C and 0.5 rpm.

The said electrically conductive paste contains a thermosetting component and some electroconductive particle. The said thermosetting component contains the thermosetting compound (curable compound curable by heating) which is solid at 25 degreeC, and a thermosetting agent. It is preferable that the said electrically conductive paste contains a liquid thermosetting compound (curable compound hardenable by heating) at 25 degreeC. The conductive paste preferably includes a flux. The said electrically conductive paste may contain the filler.

Hereinafter, other details of the present invention will be described.

(conductive particles)

The said electroconductive particle electrically connects between the electrodes of a connection object member. The said electroconductive particle will not be specifically limited if it is particle|grains which have electroconductivity. The said electroconductive particle should just have an electroconductive part on the electroconductive outer surface.

The conductive particles include, for example, organic particles, inorganic particles excluding metal particles, organic-inorganic hybrid particles or conductive particles in which the surface of metal particles is coated with a conductive layer (metal layer), metal particles substantially composed of only metal, etc. can be heard

It is preferable to have solder on an electroconductive outer surface, and, as for the said electroconductive particle contained in the said electrically conductive paste, it is more preferable that it is a solder particle. Hereinafter, the electroconductive particle which has solder on the electroconductive outer surface is demonstrated.

In FIG. 4, the electroconductive particle which can be used for the electrically conductive paste which concerns on one Embodiment of this invention is shown in sectional drawing.

The electroconductive particle 51 shown in FIG. 4 has the substrate particle 52 (resin particle etc.) and the electroconductive part 53 arrange|positioned on the outer surface 52a of the substrate particle 52. The conductive part 53 is a conductive layer. The electroconductive part 53 has coat|covered the outer surface 52a of the substrate particle 52. As shown in FIG. The electroconductive particle 51 is the covering particle|grain by which the outer surface 52a of the substrate particle 52 was coat|covered with the electroconductive part 53. Therefore, the electroconductive particle 51 has the electroconductive part 53 in the outer surface 51a.

The electroconductive part 53 is the 1st electroconductive part 54 (1st electroconductive layer) arrange|positioned on the outer surface 52a of the substrate particle 52, and the outer surface 54a of the 1st electroconductive part 54. It has a solder portion 55 (a solder layer, a second conductive portion (second conductive layer)) disposed thereon. The outer surface portion (surface layer) of the conductive portion 53 is the solder portion 55 . Therefore, the electroconductive particle 51 has the solder part 55 as a part of the electroconductive part 53, and between the substrate particle 52 and the solder part 55, it is a solder part as a part of the conductive layer 53. Separately from (55), a first conductive portion (54) is provided. In this way, the conductive part 53 may have a multilayer structure, or may have a laminated structure of two or more layers.

As described above, the conductive part 53 has a two-layer structure. As in the modified example shown in FIG. 5, the electroconductive particle 61 may have the solder part 62 as a single-layer electroconductive part (conductive layer). In the electroconductive particle which has solder on the electroconductive outer surface, the surface part (surface layer) of at least the outer side of the electroconductive part in electroconductive particle should just be a solder part. However, since preparation of electroconductive particle is easy, the electroconductive particle 51 is preferable among the electroconductive particle 51 and the electroconductive particle 61. Moreover, like the modification shown in FIG. 6, without having a substrate particle in a core, you may use 11 A of solder particles which are not core-shell particle|grains. As for the solder particles 11A, both the central portion and the conductive outer surface are formed of solder.

The conductive particles 51 and 61 and the solder particles 11A can be used for the conductive paste. From the viewpoint of effectively improving the conduction reliability between the electrodes and also enhancing the connection reliability, the solder particles 11A are particularly preferable among the conductive particles 51 and 61 and the solder particles 11A.

The said electroconductive part is not specifically limited. Gold, silver, copper, nickel, palladium, tin, etc. are mentioned as a metal which comprises the said electroconductive part. Examples of the conductive layer include a gold layer, a silver layer, a copper layer, a nickel layer, a palladium layer, or a conductive layer containing tin.

From the viewpoint of increasing the contact area between the electrode and the conductive particles and further enhancing the conduction reliability between the electrodes, the conductive particles have a resin particle and a conductive layer (first conductive layer) disposed on the surface of the resin particle it is preferable From a viewpoint of further improving the conduction|electrical_connection reliability between electrodes, it is preferable that the said electroconductive particle is electroconductive particle whose outer surface of electroconductivity at least is a low-melting-point metal layer. The said electroconductive particle has a substrate particle and the conductive layer arrange|positioned on the surface of this substrate particle, It is more preferable that the at least outer surface of the conductive layer is a low-melting-point metal layer. The said electroconductive particle has a substrate particle and the electroconductive part arrange|positioned on the surface of this substrate particle, It is more preferable that the at least outer surface of the electroconductive part is a low melting-point metal layer.

It is preferable that the said solder is a low-melting-point metal whose melting|fusing point is 450 degrees C or less. It is preferable that the said solder particle is a low-melting-point metal particle whose melting|fusing point is 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. Also, the solder contains tin. Among 100 wt% of the metal contained in the solder, the content of tin is preferably 30 wt% or more, more preferably 40 wt% or more, still more preferably 70 wt% or more, particularly preferably 90 wt% or more. . When the content of tin in the solder 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 Corporation), a fluorescence X-ray analyzer ("EDX-800HS" manufactured by Shimadzu Corporation), etc. can be measured using

By using the electroconductive particle which has the said solder on the electroconductive outer surface, the solder melts and joins to an electrode, and a solder part conducts between electrodes. For example, since the solder portion and the electrode easily come into surface contact rather than point contact, the connection resistance is lowered. In addition, the use of conductive particles having solder on the conductive outer surface increases the bonding strength between the solder portion and the electrode. As a result, separation between the solder portion and the electrode becomes more difficult to occur, effectively increasing the conduction reliability and connection reliability. .

The low-melting-point metal constituting the solder is not particularly limited. It is preferable that the said 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. Among them, 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 from the viewpoint of excellent wettability to the electrode. It is more preferable that they are a tin-bismuth alloy and a tin-indium alloy.

The solder is preferably a filler metal having a liquidus line of 450°C or lower based on JIS Z3001: Welding terminology. As a composition of the said solder, the metal composition containing zinc, gold|metal|money, silver, lead, copper, tin, bismuth, indium, etc. is mentioned, for example. Among them, a tin-indium system (117°C process) or a tin-bismuth system (139°C process) that is lead-free with a low melting point is preferable. That is, the solder preferably contains no lead, preferably contains tin and indium, or contains tin and bismuth.

In order to further increase the bonding strength between the solder portion and the electrode, the solder may contain phosphorus and tellurium, nickel, copper, antimony, aluminum, zinc, iron, gold, titanium, germanium, cobalt, bismuth, It may contain metals, such as manganese, chromium, molybdenum, and palladium. Further, from the viewpoint of further enhancing the bonding strength between the solder portion and the electrode, the solder preferably contains nickel, copper, antimony, aluminum or zinc. From the viewpoint of further enhancing the bonding strength between the solder portion and the electrode, the content of these metals for 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.

The average particle diameter of the electroconductive 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 is 30 µm or less, more preferably 20 µm or less, particularly preferably 15 µm or less, and most preferably 10 µm or less. If the average particle diameter of the said electroconductive particle is more than the said minimum and below the said upper limit, electroconductive particle can be arrange|positioned on an electrode still more efficiently. As for the average particle diameter of the said electroconductive particle, it is especially preferable that they are 3 micrometers or more and 30 micrometers or less.

The "average particle diameter" of the said electroconductive particle shows a number average particle diameter. The average particle diameter of electroconductive particle is calculated|required by observing 50 arbitrary electroconductive particles with an electron microscope or an optical microscope, for example, and calculating an average value.

In 100% by weight of the conductive paste, the content of the conductive particles is preferably 0.1% by weight or more, more preferably 1% by weight or more, still more preferably 2% by weight or more, still more preferably 10% by weight or more, It is particularly preferably 20% by weight or more, most preferably 30% by weight or more, preferably 80% by weight or less, more preferably 60% by weight or less, still more preferably 50% by weight or less. Electroconductive particle can be arrange|positioned on an electrode as content of the said electroconductive particle is more than the said minimum and below the said upper limit, it is easy to arrange|position many electroconductive particles between electrodes, and conduction|electrical_connection reliability becomes still higher. From a viewpoint of improving conduction|electrical_connection reliability still more, the one with much content of the said electroconductive particle is preferable.

(Compound curable by heating: thermosetting component)

The said thermosetting compound will not be specifically limited if it is solid at 25 degreeC and can be disperse|distributed in particulate form in an electrically conductive paste. For example, in the said electrically conductive paste at 25 degreeC, the thermosetting compound solid at the said 25 degreeC is disperse|distributed in the particulate form. In addition, in FIG. 7, the image of the thermosetting compound disperse|distributed in the form of particle|grains in the electrically conductive paste which concerns on one Embodiment of this invention was shown.

Examples of the thermosetting compound solid at 25° C. include 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, and Polythiol etc. are mentioned. As for the thermosetting compound which is solid at the said 25 degreeC, only 1 type may be used and 2 or more types may be used together.

From a viewpoint of making the dispersion state of the thermosetting compound solid at 25 degreeC in an electrically conductive paste favorable and exhibiting the effect of this invention still more effectively, the said thermosetting compound solid at 25 degreeC is a thermosetting epoxy compound solid at 25 degreeC It is preferable to be Moreover, connection reliability becomes still higher by use of an epoxy compound.

From the viewpoint of effectively improving the conduction reliability between electrodes, the melting point of the solid thermosetting compound at 25°C is preferably 40°C or more, more preferably 70°C or more, still more preferably 90°C or more, preferably 160°C. Hereinafter, more preferably, it is 140 degrees C or less, More preferably, it is 120 degrees C or less.

When melting a solid thermosetting compound at 25°C, it is difficult to rapidly lower the viscosity of the conductive paste, suppressing excessive sedimentation of conductive particles, and consequently, from the viewpoint of effectively increasing the conduction reliability between the electrodes, the solid at 25°C It is preferable that a thermosetting compound contains the 1st thermosetting compound which is solid at 25 degreeC, and the 2nd thermosetting compound which has melting|fusing point different from the said 1st thermosetting compound and is solid at 25 degreeC.

From the viewpoint of effectively increasing the conduction reliability between the electrodes, the absolute value of the difference between the melting point of the first thermosetting compound and the melting point of the second thermosetting compound is preferably 1°C or more, more preferably 5°C or more, still more preferably 10 °C or higher, preferably 30 °C or lower, more preferably 20 °C or lower.

It is preferable that the said electrically conductive paste contains the thermosetting compound liquid at 25 degreeC from a viewpoint of making the dispersion state of the said thermosetting compound solid at 25 degreeC favorable, and exhibiting the effect of this invention more effectively. Examples of the thermosetting compound liquid at 25° C. include 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, and Polythiol etc. are mentioned. As for the thermosetting compound liquid at 25 degreeC, only 1 type may be used and 2 or more types may be used together.

It is preferable that the thermosetting compound liquid at 25 degreeC is a thermosetting epoxy compound liquid at 25 degreeC from a viewpoint of making sclerosis|hardenability and viscosity of an electrically conductive paste still more favorable and improving connection reliability further.

In 100% by weight of the conductive paste, the total content of the thermosetting compound solid at 25°C and the thermosetting compound liquid at 25°C is preferably 20% by weight or more, more preferably 40% by weight or more, further Preferably it is 50 weight% or more, Preferably it is 99 weight% or less, More 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, the one with much content of the said thermosetting component is preferable.

The content of the thermosetting compound solid at 25°C and the thermosetting epoxy compound solid at 25°C in 100 wt% of the conductive paste is preferably 5 wt% or more, more preferably 10 wt% or more, preferably is 70% by weight or less, more preferably 50% by weight or less. When content of the thermosetting compound which is solid at 25 degreeC and the thermosetting epoxy compound which is solid at 25 degreeC is more than the said lower limit and below the said upper limit, the coating property of an electrically conductive paste and arrangement|positioning precision of electroconductive particle become still higher.

In 100% by weight of the conductive paste, the content of the thermosetting compound liquid at 25°C and the thermosetting epoxy compound liquid at 25°C is preferably 5% by weight or more, more preferably 10% by weight or more, preferably is 70% by weight or less, more preferably 50% by weight or less. When content of the thermosetting compound liquid at 25 degreeC and the thermosetting epoxy compound liquid at 25 degreeC is more than the said lower limit and below the said upper limit, the coating property of an electrically conductive paste and arrangement|positioning precision of electroconductive particle become still higher.

The difference between the SP value of the thermosetting compound that is solid at 25°C and the thermosetting compound that is liquid at 25°C is preferably 0.5 or more, more preferably 1 or more, preferably 3 or less, and more preferably 2 or less. If the difference of SP value is more than the said lower limit and below the said upper limit, it can exist stably as particle|grains of the thermosetting compound solid at 25 degreeC, and arrangement|positioning precision of the electroconductive particle of an electrically conductive paste becomes still higher.

(thermosetting agent: thermosetting component)

The said thermosetting agent thermosets the said thermosetting compound. Examples of the thermosetting agent include an imidazole curing agent, an amine curing agent, a phenol curing agent, a polythiol curing agent, an acid anhydride, a thermal cationic initiator, and a thermal radical generating agent. As for the said thermosetting agent, only 1 type may be used and 2 or more types may be used together.

Among them, an imidazole curing agent, a polythiol curing agent, or an amine curing agent is preferable because the conductive paste can be cured even more rapidly at a low temperature. Moreover, since storage stability increases when the said thermosetting agent and the sclerosing|hardenable compound which can be hardened by heating are mixed, a latent hardening|curing agent is preferable. The latent curing agent is preferably a latent imidazole curing agent, a latent polythiol curing agent, or a latent amine curing agent. Moreover, the said thermosetting agent may be coat|covered with polymeric substances, 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- Phenylimidazolium trimellitate, 2,4-diamino-6-[2′-methylimidazolyl-(1′)]-ethyl-s-triazine and 2,4-diamino-6-[2 '-methylimidazolyl-(1')]-ethyl-s-triazine isocyanuric acid adduct etc. are mentioned.

The polythiol curing agent is not particularly limited, and trimethylolpropane tris-3-mercaptopropionate, pentaerythritol tetrakis-3-mercaptopropionate and dipentaerythritol hexa-3-mercaptopropionate and the like.

The amine curing agent is not particularly limited, and 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 curing agent include an iodonium-based cation curing agent, an oxonium-based cation curing agent, and a sulfonium-based cation curing agent. Examples of the iodonium-based cationic curing agent include bis(4-tert-butylphenyl)iodonium hexafluorophosphate. 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. Azobisisobutyronitrile (AIBN) etc. are mentioned as said azo compound. Examples of the organic peroxide include di-tert-butyl peroxide and methyl ethyl ketone peroxide.

The reaction initiation temperature (curing 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. , more preferably 150°C or lower, particularly preferably 140°C or lower. Electroconductive particle is arrange|positioned on an electrode still more efficiently that the reaction start temperature of the said thermosetting agent is more than the said minimum and below the said upper limit. 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 a viewpoint of arranging electroconductive particle more efficiently on an electrode, it is preferable that the reaction start temperature of the said thermosetting agent is lower than melting|fusing point of the solder in electroconductive particle, It is more preferable that it is 5 degreeC or more lower, and it is 10 degreeC It is more preferable that it is lower than that.

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. With respect to 100 parts by weight of the thermosetting compound solid at 25° C., the content of the thermosetting agent is preferably 0.01 parts by weight or more, more preferably 1 part by weight or more, preferably 200 parts by weight or less, more preferably 100 parts by weight or less, still more preferably 75 parts by weight or less, still more preferably 50 parts by weight or less, particularly preferably 37.5 parts by weight or less. The content of the thermosetting agent is preferably 0.01 part by weight or more, more preferably 1 part by weight or more, with respect to a total of 100 parts by weight of the thermosetting compound that is solid at 25° C. and the thermosetting compound that is liquid at 25° C. Preferably 200 parts by weight or less, more preferably 100 parts by weight or less, and still more 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)

It is preferable that the said electrically conductive paste contains a flux. When the said electroconductive particle is electroconductive particle which has a solder on the electroconductive surface, it is preferable to use 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. 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. It is preferable that the said flux is an organic acid which has two or more carboxyl groups, and pine resin. The organic acid having two or more carboxyl groups may be sufficient as the said flux, and pine resin may be sufficient as it. By using 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 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 160°C or lower, even more preferably 150°C or higher. °C or lower, more preferably 140 °C or lower. When the melting point 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. It is preferable that the melting point of the flux is 80°C or more and 190°C or less. It is particularly preferable that the flux has a melting point of 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 (melting point) 142 degreeC), etc. dicarboxylic acid, 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 arranging the solder on the electrode, the melting point of the flux is preferably lower than the melting point of the solder in the solder particles, more preferably 5°C or more lower, and 10°C or more lower more preferably.

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

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

The content of the flux in 100% by weight of the conductive paste is preferably 0.5% by weight or more, preferably 30% by weight or less, and more preferably 25% by 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, it becomes more difficult to form an oxide film on the surface of the solder and the electrode, and the oxide film formed on the surface of the solder and the electrode can be removed more effectively.

(filler)

The said electrically conductive paste may contain the filler. By use of a filler, the latent thermal expansion of the hardened|cured material of an electrically conductive paste can be suppressed. However, from a viewpoint of improving the coating property of an electrically conductive paste and the arrangement|positioning precision of electroconductive particle further, it is better not to use a filler, and when using a filler, the less content of a filler is so good.

Preferably, the conductive paste does not include a filler, or contains a filler in an amount of 1 wt% or less of 100 wt% of the conductive paste. When an electrically conductive paste contains a filler, content of a filler becomes like this. More preferably, it is 0.5 weight% or less.

Examples of the filler include inorganic fillers such as silica, talc, aluminum nitride and alumina. An organic filler may be sufficient as the said filler, and an organic-inorganic composite filler may be sufficient as it. As for the said filler, only 1 type may be used and 2 or more types may be used together.

(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

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 a first reactant of bisphenol F with 1,6-hexanediol diglycidyl ether and bisphenol F-type epoxy resin:

72 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) and 1,6-hexanedioldi 70 parts by weight of glycidyl ether and 30 parts by weight of bisphenol F-type epoxy resin ("EPICLON EXA-830CRP" manufactured by DIC) were placed in a three-neck flask, and dissolved at 150°C under a nitrogen flow. Then, 0.1 weight part of tetra-n-butylsulfonium bromide which is an addition reaction catalyst of a hydroxyl group and an epoxy group was added, and the polymer A was obtained by carrying out addition polymerization reaction at 150 degreeC under nitrogen flow for 6 hours.

It was confirmed by NMR that the addition polymerization reaction had progressed, and the polymer A has, in its main chain, 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 are bonded. , it was also confirmed that the epoxy groups were at both ends.

The weight average molecular weight of the polymer A obtained by GPC was 10000, and the number average molecular weight was 3500.

Polymer B: Rigid skeleton phenoxy resin with epoxy groups at both ends, "YX6900BH45" manufactured by Mitsubishi Chemical Corporation, weight average molecular weight 16000

Thermosetting compound 1 (solid at 25 ° C, thermosetting epoxy compound, "EX-201" manufactured by Nagase Chemtex Co., Ltd. is crystallized at -5 ° C, washed with hexane, and used after removal of hexane by vacuum drying)

Thermosetting compound 2 (solid at 25°C, thermosetting epoxy compound, DIC Co., Ltd. “HP-4032D” crystallized at -5°C, washed with hexane, and removed by vacuum drying before use)

Thermosetting compound 3 (liquid at 25°C, thermosetting epoxy compound, "1,6-hexanediol glycidyl ether" manufactured by Yokkaichi Chigosei Co., Ltd.)

Thermosetting compound 4 (liquid at 25°C, thermosetting polythiol compound, Showa Denko Co., Ltd. “Carenz MT PE1”)

Thermosetting compound 5 (solid at 25°C, thermosetting epoxy compound, ADEKA Co., Ltd. “EP-3300” crystallizes at -5°C, washes with hexane, and removes hexane by vacuum drying before use)

Thermosetting compound 6 (solid at 25°C, thermosetting epoxy compound, Nissan Chemical Co., Ltd. “TEPIC-SS” is crystallized at -5°C, washed with hexane, and hexane is removed by vacuum drying before use)

Thermosetting compound 7 (solid at 25°C, thermosetting epoxy compound, “TEP-G” manufactured by Asahi Yugiza Kogyo Co., Ltd. is crystallized at -5°C, washed with hexane, and hexane is removed by vacuum drying before use)

Flux (“Adipic Acid” manufactured by Wako Junyaku High School)

Filler (hydrophobic fumed silica, Tokuyama Co., Ltd. "Leo Seal MT-10")

Electroconductive particle 1 (SnBi solder particle, melting point 139°C, "ST-5" manufactured by Mitsui Industries, Ltd., average particle diameter of 5.4 µm)

Conductive particles 2 (SnBi solder particles, melting point 139°C, “DS-10” manufactured by Mitsui Industries, Ltd., average particle diameter of 12 μm)

Electroconductive particle 3: (resin core solder coated particle, produced by the following procedure)

Divinylbenzene resin particles (“Micropearl SP-207” manufactured by Sekisui Chemical Industry Co., Ltd., average particle diameter of 7 μm) 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, using an electrolytic plating solution containing tin and bismuth, electrolytic plating was performed to form a solder layer having a thickness of 1 µm. In this way, a 1 µm-thick copper layer is formed on the surface of the resin particles, and a 1 µm-thick solder layer (tin: bismuth = 43 wt%: 57 wt%) is formed on the surface of the copper layer. Particles (average particle diameter of 14 µm, resin core solder coated particles) were produced.

Electroconductive particle 4: Au plating particle|grains of divinylbenzene resin particle ("Au-210" by Sekisui Chemical Industry Co., Ltd., average particle diameter of 10 micrometers)

Phenoxy resin (“YP-50S” manufactured by Nippon Steel Chemicals)

(Examples 1 to 10, 12 to 17)

(1) Preparation of anisotropic conductive paste

The components shown in following Tables 1 and 2 were mix|blended by the compounding quantity shown in following Table 1, 2, and the anisotropic electrically conductive paste was obtained.

In addition, only the polymer A and the thermosetting compound in the component shown in following Tables 1 and 2 were mix|blended, and it stirred at 120 degreeC at 60 rpm for 1 hour. Then, it cooled to room temperature over 3 hours, stirring at 60 rpm. Then, it pinched|interposed on a glass plate, and the particle diameter of the solid thermosetting compound at 25 degreeC which precipitated was observed with the optical microscope. The particle diameters of 100 particles were measured, and the average particle diameter was calculated|required.

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

L/S prepared the glass epoxy board|substrate (FR-4 board|substrate) (1st connection object member) which has a copper electrode pattern (copper electrode thickness of 10 micrometers) whose upper surface is 50 micrometers/50 micrometers. Furthermore, L/S prepared the flexible printed circuit board (2nd connection object member) which has a copper electrode pattern (copper electrode thickness of 10 micrometers) of 50 micrometers/50 micrometers on the lower surface.

The overlapping area of the glass epoxy substrate and the flexible printed circuit board was 1.5 cm x 4 mm, and the number of connected electrodes was 75 pairs.

On the upper surface of the said glass epoxy board|substrate, the anisotropic electrically conductive paste immediately after preparation was coated so that it might become 50 micrometers in thickness by screen printing, and the anisotropic electrically conductive paste layer was formed. Next, the said flexible printed circuit board was laminated|stacked on the upper surface of an anisotropic electrically conductive paste layer so that electrodes may 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 an anisotropic electrically conductive paste layer might become 185 degreeC, and the anisotropic electrically conductive paste layer was hardened at 185 degreeC, and the 1st bonded structure was obtained.

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

L/S prepared the glass epoxy board|substrate (FR-4 board|substrate) (1st connection object member) which has a copper electrode pattern (copper electrode thickness of 10 micrometers) whose upper surface is 75 micrometers/75 micrometers. Furthermore, L/S prepared the flexible printed circuit board (2nd connection object member) which has on the lower surface the copper electrode pattern (copper electrode thickness of 10 micrometers) of 75 micrometers/75 micrometers.

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

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

L/S prepared the glass epoxy board|substrate (FR-4 board|substrate) (1st connection object member) which has a copper electrode pattern (copper electrode thickness of 10 micrometers) whose upper surface is 100 micrometers / 100 micrometers. Furthermore, L/S prepared the flexible printed circuit board (2nd connection object member) which has a copper electrode pattern (copper electrode thickness 10 micrometers) of 100 micrometers / 100 micrometers on the lower surface.

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

(5) Production of the fourth bonded structure (L/S = 50 µm/50 µm)

The glass epoxy board|substrate (FR-4 board|substrate) (1st connection object member) for obtaining the said 1st bonded structure, and the flexible printed circuit board (2nd connection object member) for obtaining the said 1st bonded structure 120 degreeC and humidity 20 % stored for 1 hour. Except having used the 1st, 2nd connection object member after storage, it carried out similarly to preparation of 1st bonded structure, and obtained the 4th bonded structure.

(6) Preparation of the fifth bonded structure (L/S = 75 µm/75 µm)

The glass epoxy board|substrate (FR-4 board|substrate) (1st connection object member) for obtaining the said 2nd bonded structure, and the flexible printed circuit board (2nd connection object member) for obtaining the said 2nd bonded structure 120 degreeC and humidity 20 % stored for 1 hour. Except having used the 1st, 2nd connection object member after storage, it carried out similarly to preparation of the 2nd bonded structure, and obtained the 5th bonded structure.

(7) Preparation of 6th bonded structure (L/S = 100 µm/100 µm)

The glass epoxy board|substrate (FR-4 board|substrate) (1st connection object member) for obtaining the said 3rd bonded structure, and the flexible printed circuit board (2nd connection object member) for obtaining the said 3rd bonded structure 120 degreeC and humidity 20 % stored for 1 hour. Except having used the 1st, 2nd connection object member after storage, it carried out similarly to preparation of 3rd bonded structure, and obtained the 6th bonded structure.

(Example 11)

The electrode size/interelectrode space is 50 µm/50 µm (for the first and fourth bonded structures), 75 µm/75 µm (for the second and fifth bonded structures), 100 µm/100 µm (for the third and fourth bonded structures) 6 Using a glass epoxy substrate (size 30 × 30 mm, thickness 0.4 mm) having a square semiconductor chip (thickness 400 μm) of 5 mm on one side (for a 6-connected structure) and an electrode opposed thereto, the first and second 2, 3rd, 4th, 5th, and 6th bonded structure were obtained.

(Comparative Example 1)

10 parts by weight of a phenoxy resin ("YP-50S" manufactured by Nippon Chemicals Co., Ltd.) was dissolved in methyl ethyl ketone (MEK) so that the solid content was 50% by weight to obtain a solution. The components except for the phenoxy resin shown in Table 2 below were blended with the blending amount shown in Table 2 below, and the total amount of the solution, stirred at 2000 rpm for 5 minutes using a planetary stirrer, and then dried using a bar coater. It was coated on a mold release PET (polyethylene terephthalate) film so that it may become 30 micrometers. The anisotropic conductive film was obtained by removing MEK by vacuum-drying at room temperature.

Except having used the anisotropic conductive film, it carried out similarly to Example 1, and obtained the 1st, 2nd, 3rd, 4th, 5th, 6th bonded structure.

(evaluation)

(1) Viscosity

The viscosity (eta)1 in 25 degreeC and 0.5 rpm of an anisotropic electrically conductive paste was measured using the E-type viscometer (made by Toki Sangyo Co., Ltd.). In addition, the viscosity (eta)2 in 25 degreeC and 5 rpm of an anisotropic electrically conductive paste was measured using the E-type viscometer (made by Toki Sangyo Co., Ltd.). Ratio (η1/η2) was calculated|required from the obtained measured value.

In addition, melting|fusing point -5 degreeC of the solder in the electroconductive particle of an anisotropic electrically conductive paste, and viscosity (eta)1' in 0.5 rpm were measured using the E-type viscometer (made by Toki Sangyo Co., Ltd.). In addition, melting|fusing point -5 degreeC of the solder in the electroconductive particle of an anisotropic electrically conductive paste, and viscosity (eta)2' in 5 rpm was measured using the E-type viscometer (made by Toki Sangyo Co., Ltd.). Ratio (η1'/η2') was calculated|required from the obtained measured value. The ratio (η1'/η2') was determined based on the following criteria.

[Criteria for determination of ratio (η1'/η2')]

A: 1 or more and 2 or less

B: It does not correspond to the standard of A

(2) distributed state

In the anisotropic electrically conductive paste, the dispersed state and particle diameter of the thermosetting compound solid at 25 degreeC were observed using the electron microscope. The dispersion state was judged according to the following criteria.

[Criteria for judgment of dispersed state]

○○: In the conductive paste, a thermosetting compound solid at 25°C is dispersed in particulate form, and the particle diameter of the particulate thermosetting compound is 1 µm or more and 10 µm or less

○: In the conductive paste, a thermosetting compound solid at 25° C. is dispersed in particulate form, and the particle diameter of the particulate thermosetting compound is more than 10 µm and 40 µm or less.

(triangle|delta): In the electrically conductive paste, the thermosetting compound solid at 25 degreeC is disperse|distributed in particulate form, and the particle diameter of a particulate-form thermosetting compound exceeds 40 micrometers.

x: In the electrically conductive paste, the thermosetting compound solid at 25 degreeC does not disperse|distribute in particulate form

(3) Coatability

In order to obtain a 1st bonded structure, when the anisotropic electrically conductive paste immediately after preparation was coated so that it might become 50 micrometers in thickness by screen printing, it was evaluated whether coating-in unevenness generate|occur|produced. The coating workability was judged according to the following criteria.

[Criteria for judgment of coating workability]

○: Coating is possible with a thickness variation of less than 5 μm, and the anisotropic conductive paste does not spread in unintentional areas

△: Coating is possible with a thickness deviation of 5 μm or more and less than 10 μm, and the anisotropic conductive paste does not spread in unintended areas

×: A thickness deviation of 10 μm or more occurs after coating, or an anisotropic conductive paste spreads in an unintended area

(4) Interval between electrodes

By cross-sectional observation of the obtained 1st bonded structure, the space|interval D1 (distance D1 of a connection part) between the electrodes in the position which the upper and lower electrodes oppose was evaluated.

(5) Arrangement precision of electroconductive particle on an electrode

In the cross section of the obtained 1st, 2nd, 3rd bonded structure (cross section of the direction shown in FIG. 1), the electroconductive particle arrange|positioned between electrodes in 100% of the total area of the electroconductive particle (solder part etc.) shown in the cross section. The area A1 (%) of the conductive particles (solder particles, etc.) remaining away from the cured product was evaluated. Moreover, the average of the area in five cross sections was computed. The following reference|standard determined the arrangement|positioning precision of the electroconductive particle on an electrode.

[Criterion of determination of arrangement precision of electroconductive particle on electrode]

○○: Area A1 is 0%

○: Area A1 is greater than 0% and less than or equal to 10%

△: Area A1 is greater than 10% and less than or equal to 30%

×: Area A1 exceeds 30%

(6) Reliability of conduction between upper and lower electrodes

In the obtained 1st, 2nd, 3rd, 4th, 5th, 6th bonded structure (n = 15 pieces), the connection resistance between the upper and lower electrodes was respectively measured by the 4-terminal method. The average value of connection resistance was computed. In addition, from the relationship of voltage=currentxresistance, connection resistance can be calculated|required by measuring the voltage when a constant current flows. Conduction reliability was determined based on the following criteria.

[Criteria for judgment of continuity reliability]

○○: The average value of the connection resistance is 8.0 Ω or less

○: The average value of the connection resistance exceeds 8.0 Ω and 10.0 Ω or less

△: The average value of the connection resistance exceeds 10.0 Ω and 15.0 Ω or less

×: The average value of the connection resistance exceeds 15.0 Ω

(7) Insulation reliability between adjacent electrodes

In the obtained 1st, 2nd, 3rd, 4th, 5th, 6th 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. It applied, and the resistance value was measured at 25 places. Insulation reliability was judged according to the following criteria.

[Criteria for judgment of 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

The results are shown in Tables 1 and 2 below.

From the difference between the results of Example 1 and Example 11, when the second connection object member is a flexible printed circuit board, compared with the case where the second connection object member is a semiconductor chip, the conduction reliability by the use of the conductive paste of the present invention is improved. It turns out that the improvement effect is acquired still more effectively. In addition, in the evaluation of the conduction reliability of Examples 16 and 17 (result ○○), since a plurality of 25°C solid thermosetting compounds having different melting points are used, the evaluation of other examples (including result ○○) The specific value of the connection resistance was low. In Examples 16 and 17, compared with other Examples, the conduction reliability was particularly excellent.

1, 1X: Connection structure
2: first connection target member
2a: first electrode
3: 2nd connection target member
3a: second electrode
4, 4X: connection part
4A, 4XA: Solder
4B, 4XB: Cured part
11: conductive paste
11A: Solder particles
11B: thermosetting component
51: conductive particles
51a: outer surface
52: substrate particle
52a: outer surface
53: conductive part
54: first conductive part
54a: outer surface
55: solder part
61: conductive particles
62: solder part

Claims (18)

It contains a thermosetting component and a plurality of conductive particles,
The thermosetting component contains a thermosetting compound that is solid at 25°C, and a thermosetting agent,
In the conductive paste, the thermosetting compound solid at 25° C. is dispersed in the form of particles,
The electrically conductive paste whose ratio with respect to the viscosity in 25 degreeC and 5 rpm of the viscosity in 25 degreeC and 0.5 rpm is 2.5 or more and 7 or less. The electrically conductive paste of Claim 1 containing the thermosetting compound which is liquid at 25 degreeC. The electrically conductive paste of Claim 1 or 2 whose thermosetting compound solid at 25 degreeC is a thermosetting epoxy compound solid at 25 degreeC. 3. The second thermosetting compound according to claim 1 or 2, wherein the thermosetting compound solid at 25°C has a melting point different from that of the first thermosetting compound and the first thermosetting compound being solid at 25°C and is solid at 25°C. A conductive paste containing a thermosetting compound. The electrically conductive paste of Claim 1 or 2 in which the said electroconductive particle has solder on the electroconductive outer surface. The conductive paste according to claim 5, wherein the conductive particles are solder particles. The ratio of the viscosity in melting|fusing point -5 degreeC and 0.5 rpm of the solder in the said electroconductive particle with respect to the viscosity in melting|fusing point -5 degreeC of the solder in the said electroconductive particle, and 5 rpm is 1 or more and 2 or less conductive paste. The electrically conductive paste of Claim 1 or 2 whose particle diameters of the said thermosetting compound in particulate form are 1 micrometer or more and 40 micrometers or less. The electrically conductive paste of Claim 1 or 2 whose ratio with respect to the viscosity in 25 degreeC and 5 rpm of the viscosity in 25 degreeC and 0.5 rpm is 4 or more and 7 or less. The conductive paste according to claim 1 or 2, comprising a flux. The electrically conductive paste of Claim 1 or 2 which does not contain a filler or contains a filler in the quantity of 1 weight% or less in 100 weight% of electrically conductive pastes. It is a manufacturing method of the electrically conductive paste of Claim 1 or 2,
A mixture is obtained by mixing a thermosetting compound which is solid at 25°C, a thermosetting component containing a thermosetting agent, and a plurality of conductive particles, and the mixture is then subjected to a melting point of the thermosetting compound solid at 25° C. A conductive paste in which the thermosetting compound solid at 25° C. is dispersed in particulate form is obtained by heating below the temperature to melt the thermosetting compound solid at 25° C. and then solidifying it, or
After making the thermosetting compound solid at 25 ° C into particulate form, it is a mixture containing a thermosetting compound which is particulate and solid at 25 ° C and a thermosetting component containing a thermosetting agent, and a plurality of conductive particles, and is solid at 25 ° C. The manufacturing method of the electrically conductive paste which obtains the electrically conductive paste in which the thermosetting compound is disperse|distributed in the particulate form. 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 connecting portion connecting the first to-be-connected member and the second to-be-connected member;
The said connection part is formed with the electrically conductive paste of Claim 1 or 2,
The bonded structure in which the said 1st electrode and the said 2nd electrode are electrically connected by the said electroconductive particle in the said connection part. The connection structure of Claim 13 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 solid thermosetting compound at 25° C. and above the curing temperature of the thermosetting component, the connecting portion connecting the first to-be-connected member and the second to-be-connected member is applied to the conductive paste. The manufacturing method of a bonded structure provided with the process of forming by this, and electrically connecting the said 1st electrode and the said 2nd electrode with the said electroconductive particle in the said connection part. The connection structure of Claim 15 in which the weight of the said 2nd connection object member is applied to the said electrically conductive paste without performing pressurization in the process of arranging the said 2nd connection object member and the process of forming the said connection part. manufacturing method. The manufacturing method of the bonded structure of Claim 15 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

Images