KR20160130738A - Conductive paste, connection structure, and production method for connection structure - Google Patents

Abstract

A conductive paste capable of efficiently disposing the solder particles on the electrode and enhancing the conduction reliability between the electrodes is provided. The conductive paste according to the present invention includes a thermosetting component and a plurality of solder particles, wherein when the thermosetting component and the solder particles are heated at a heating rate of 10 ° C / minute, respectively, Wherein an exothermic peak top temperature in the final curing of the component is higher than an endothermic peak top temperature in melting of the solder particles and an exothermic peak top temperature in the main curing of the thermosetting component and a melting peak temperature in the melting of the solder particles The maximum value of the difference in the endothermic peak top temperature in the temperature range from 10 占 폚 to 70 占 폚.

Description

TECHNICAL FIELD [0001] The present invention relates to a conductive paste, a connection structure, and a method of manufacturing a connection structure,

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

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

The anisotropic conductive material can be used for various connection structures, for example, connection (FOG (Film on Glass)) between a flexible printed board and a glass substrate, connection (COF (Chip on Film)) between a semiconductor chip and a flexible printed board, (COG (Chip on Glass)) between a semiconductor chip and a glass substrate and connection (FOB (Film on Board)) between a flexible printed substrate and a glass epoxy substrate.

When the electrodes of the flexible printed circuit board and the electrodes of the glass epoxy substrate are electrically connected by the anisotropic conductive material, an anisotropic conductive material containing conductive particles is disposed on the glass epoxy substrate. Subsequently, the flexible printed circuit board is laminated and heated and pressed. Thereby, the anisotropic conductive material is cured, and the electrodes are electrically connected through the conductive particles to obtain a connection structure.

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

Further, Patent Document 1 discloses a bonding method using the adhesive tape. Specifically, the first substrate, the adhesive tape, the second substrate, the adhesive tape and the third substrate are laminated in this order from the bottom to obtain a laminate. At this time, the first electrode formed on the surface of the first substrate and the second electrode formed on the surface of the second substrate are opposed to each other. Further, the second electrode formed on the surface of the second substrate is opposed to the third electrode formed on the surface of the third substrate. Then, the laminate is heated and bonded at a predetermined temperature. Thus, a connection structure is obtained.

WO2008 / 023452A1

The adhesive tape described in Patent Document 1 is in the form of a film, not a paste. As a result, it is difficult to efficiently dispose the solder powder on the electrode (line). For example, in the adhesive tape described in Patent Document 1, a part of the solder powder is likely to be disposed in an area (space) where no electrode is formed. The solder powder disposed in the region where no electrode is formed does not contribute to the conduction between the electrodes.

In addition, even in the case of an anisotropic conductive paste containing a solder powder, the solder powder may not be efficiently arranged on the electrode (line).

An object of the present invention is to provide a conductive paste capable of efficiently disposing solder particles on an electrode and improving reliability of conduction between electrodes. The present invention also provides a connection structure using the conductive paste and a manufacturing method of the connection structure.

According to a broad aspect of the present invention, there is provided a thermosetting resin composition comprising a thermosetting component and a plurality of solder particles, wherein when the thermosetting component and the solder particles are heated at a heating rate of 10 ° C / Wherein an exothermic peak top temperature in the final curing of the component is higher than an endothermic peak top temperature in melting of the solder particles and an exothermic peak top temperature in the main curing of the thermosetting component and a melting peak temperature in the melting of the solder particles Wherein the maximum value of the difference in the endothermic peak top temperature in the step (a) is 10 占 폚 or more and 70 占 폚 or less.

In a specific aspect of the conductive paste according to the present invention, when the heat-curable component and the solder particles are heated at a temperature raising rate of 10 ° C / minute to measure the differential scanning calorie, The peak value of the difference between the heat generation starting temperature of the thermosetting component and the endothermic peak top temperature in melting of the solder particles is 5 占 폚 or more and 50 占 폚 or less.

In a specific aspect of the conductive paste according to the present invention, the conductive paste includes a flux, and when the differential scanning calorimetry is performed by heating the thermosetting component at a temperature raising rate of 10 캜 / minute, Is higher than the activation temperature of the flux.

In a specific aspect of the conductive paste according to the present invention, the conductive paste includes a flux, and when the solder particles are heated at a heating rate of 10 캜 / minute to measure the differential scanning calorie, Of the endothermic peak top temperature of the flux is higher than the activation temperature of the flux.

In a specific aspect of the conductive paste according to the present invention, when the conductive paste contains flux and the differential scanning calorie is measured by heating the thermosetting component and the solder particles at a temperature raising rate of 10 ° C / minute, The exothermic peak top temperature in final curing of the thermosetting component is higher than the activation temperature of the flux and the endothermic peak top temperature in melting of the solder particles is higher than the active temperature of the flux.

In a specific aspect of the conductive paste according to the present invention, the content of the solder particles in 100 wt% of the conductive paste is 10 wt% or more and 70 wt% or less.

In a specific aspect of the conductive paste according to the present invention, the viscosity at 25 캜 is not less than 10 Pa · s and not more than 800 Pa · s.

In a specific aspect of the conductive paste according to the present invention, the lowest value of the viscosity in the temperature range below the melting point of the solder particles is 0.1 Pa · s or more and 10 Pa · s or less.

According to a broad aspect of the present invention, there is provided a light emitting device comprising: a first connection target member having at least one first electrode on a surface; a second connection target member having at least one second electrode on a surface; And a connection portion connecting the second connection target member, wherein the connection portion is formed by the conductive paste described above, and the first electrode and the second electrode are electrically connected by the solder portion in the connection portion The connection structure is provided.

According to a broad aspect of the present invention, there is provided a method of manufacturing a conductive paste, comprising the steps of: disposing the conductive paste on a surface of a first connection target member having at least one first electrode on a surface thereof using the conductive paste; Disposing a second connection target member having at least one second electrode on its surface on a surface opposite to the first connection target member side so that the first electrode and the second electrode face each other; The connection portion connecting the first connection target member and the second connection target member is formed by the conductive paste by heating the conductive paste at a temperature equal to or higher than the melting point of the particles and not lower than the curing temperature of the thermosetting component, And a step of electrically connecting the first electrode and the second electrode to each other by a solder portion in the connection portion, It is.

In a specific aspect of the method of manufacturing a connection structure according to the present invention, in the step of disposing the second connection target member and the step of forming the connection portion, the conductive paste is not subjected to pressing, Is weighted.

It is preferable that the second connection target member is a resin film, a flexible printed circuit board, a flexible flat cable, or a rigid flexible substrate.

The conductive paste according to the present invention includes a thermosetting component and a plurality of solder particles, wherein when the thermosetting component and the solder particles are heated at a heating rate of 10 ° C / minute, respectively, Wherein an exothermic peak top temperature in the final curing of the component is higher than an endothermic peak top temperature in melting of the solder particles and an exothermic peak top temperature in the main curing of the thermosetting component and a melting peak temperature in the melting of the solder particles The solder particles can be efficiently arranged on the electrodes and the reliability of the conduction between the electrodes can be improved when the electrodes are electrically connected to each other .

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a partially cut-away front sectional view schematically showing a connection structure obtained by using a conductive paste according to an embodiment of the present invention. FIG.
2 (a) to 2 (c) are diagrams for explaining respective steps of an example of a method for manufacturing a connection structure using a conductive paste according to an embodiment of the present invention.
3 is a partial cutaway front sectional view showing a modification of the connection structure.
4 is a schematic diagram showing an example of a relationship between an exothermic peak in final curing of a thermosetting component in differential scanning calorimetry measurement and an endothermic peak in melting of solder particles.
5A and 5B are images showing an example of a connection structure using the conductive paste included in the embodiment of the present invention, and Figs. 5A and 5B are sectional views. Fig.
Figs. 6A, 6B and 6C are diagrams showing an example of a connection structure using conductive paste not included in the embodiment of the present invention, and Figs. 6A and 6B are cross- And Fig. 6C is a planar image.

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

The conductive paste according to the present invention includes a thermosetting component and a plurality of solder particles. In the conductive paste according to the present invention, when the thermosetting component and the solder particles are heated at a temperature raising rate of 10 캜 / minute to perform differential scanning calorimetry, the exothermic peak top temperature in the final curing of the thermosetting component , An upper limit of the difference between the exothermic peak top temperature in the main curing of the thermosetting component and the endothermic peak top temperature in the melting of the solder particles is higher than the endothermic peak top temperature in the melting of the solder particles is 10 ≪ / RTI >

The thermosetting component is heated at a heating rate of 10 DEG C / minute to perform differential scanning calorimetry (DSC). Further, the solder particles are heated at a heating rate of 10 DEG C / minute to perform differential scanning calorimetry (DSC). As schematically shown in Fig. 4, in this DSC, in the conductive paste according to the present invention, the exothermic peak top P1t temperature in the main curing of the thermosetting component is the endothermic peak in melting of the solder particles It is higher than top P2t temperature. The maximum value of the difference between the exothermic peak top P1t temperature and the endothermic peak top P2t temperature is 10 占 폚 to 70 占 폚. The exothermic peak top P1t and the endothermic peak top P2t refer to a temperature at which the exothermic peak or endothermic peak P2 or the exothermic peak P2 is the highest. The exothermic peak P1 refers to the temperature at which the amount of heat generation decreases from the portion at which the amount of heat generation starts to rise from the base line B1 (the temperature at the part starts to rise from the heat generation start temperature) to the exothermic peak top P1t, Lt; / RTI > The endothermic peak P2 is a temperature at which the endothermic amount starts to rise from the base line B2 (the temperature at that portion is the endothermic start temperature), the endothermic peak reaches the endothermic peak top P2t, Lt; / RTI > It is preferable that the exothermic peak P1 indicating the exothermic peak top P1t temperature in the main curing of the thermosetting component is the main exothermic peak having the highest heat generation amount. In order for the exothermic peak top P1t temperature and the heat absorption peak top P2t temperature to satisfy the above-described relationship, the kind of the thermosetting compound, the kind of the thermosetting agent and the composition of the solder particle in the thermosetting component may be appropriately adjusted.

In the conductive paste according to the present invention, since the above-described configuration is adopted, when a plurality of solder particles are easily collected between the electrodes when the electrodes are electrically connected, a plurality of solder particles can be efficiently Can be deployed. In addition, a part of the plurality of solder particles is hardly arranged in a region (space) where no electrode is formed, and the amount of solder particles arranged in an area where no electrode is formed can be considerably reduced. Therefore, the conduction reliability between the electrodes can be improved. In addition, it is possible to prevent electrical connection between adjacent electrodes in the lateral direction which should not be connected, and the insulation reliability can be improved. In order to obtain such an effect, the exothermic peak top temperature in the final curing of the thermosetting component and the endothermic peak top temperature in the melting of the solder particles satisfy the above-mentioned relation. If the exothermic peak top temperature in the main curing of the thermosetting component and the endothermic peak top temperature in the melting of the solder particles satisfy the above-mentioned relationship, excessive flow of the thermosetting component is suppressed after the solder particles are collected Therefore, the solder particles are hardly dispersed. Therefore, it is considered that the solder particles are efficiently arranged on the electrodes.

From the viewpoint of more efficiently arranging the solder particles on the electrode, when the thermosetting component and the solder particles are heated at a temperature raising rate of 10 deg. C / minute to measure the differential scanning calorie, Is preferably higher than the endothermic peak top temperature in the melting of the solder particles, more preferably 5 ° C or more.

From the viewpoint of more efficiently arranging the solder particles on the electrode, the absolute value of the difference between the heat generation initiation temperature of the thermosetting component and the endothermic peak top temperature in the melting of the solder particles is preferably 5 占 폚 or higher Preferably 10 ° C or higher, preferably 50 ° C or lower, more preferably 35 ° C or lower.

The conductive paste according to the present invention can be suitably used in the following manufacturing method of the connection structure according to the present invention.

In the method for manufacturing a connection structure according to the present invention, a conductive paste, a first connection object member, and a second connection object member are used. The conductive material used in the method for manufacturing a connection structure according to the present invention is not a conductive film but a conductive paste. The conductive paste includes a plurality of solder particles and a thermosetting component. The first connection target member has at least one first electrode on its surface. The second connection object member has at least one second electrode on its surface.

The method for manufacturing a connection structure according to the present invention includes the steps of disposing a conductive paste according to the present invention on the surface of the first connection target member; Placing the second connection target member so that the first electrode and the second electrode face each other; and heating the conductive paste to a temperature higher than the melting point of the solder particles and a curing temperature of the thermosetting component, A connection portion connecting the first connection target member and the second connection target member is formed by the conductive paste and the first electrode and the second electrode are electrically connected to each other by the solder portion of the connection portion . In the method of manufacturing a connection structure according to the present invention, in the step of disposing the second connection target member and the step of forming the connection portion, the weight of the second connection object member is not applied to the conductive paste, . In the method of manufacturing a connection structure according to the present invention, in the step of disposing the second connection target member and the step of forming the connection portion, the conductive paste is subjected to a pressing force exceeding the force of the weight of the second connection object member It is preferable not to apply.

In the method of manufacturing a connection structure according to the present invention, since the above-described structure is employed, a plurality of solder particles are easily collected between the first electrode and the second electrode, and a plurality of solder particles are efficiently arranged can do. In addition, a part of the plurality of solder particles is hardly arranged in a region (space) where no electrode is formed, and the amount of solder particles arranged in an area where no electrode is formed can be considerably reduced. Therefore, the conduction reliability between the first electrode and the second electrode can be improved. In addition, it is possible to prevent electrical connection between adjacent electrodes in the lateral direction which should not be connected, and the insulation reliability can be improved.

As described above, in order to efficiently arrange a plurality of solder particles on the electrode and considerably reduce the amount of the solder particles disposed in the region where no electrode is formed, it is necessary to use a conductive paste instead of a conductive film , The present inventors discovered.

In the step of disposing the second connection target member and the step of forming the connection portion, if the weight of the second connection target member is applied to the conductive paste without applying pressure, before the connection portion is formed, The solder particles arranged in the regions (spaces) which are not formed are more likely to be gathered between the first electrode and the second electrode, and a plurality of solder particles can be efficiently arranged on the electrodes (lines) They found. In the present invention, a configuration in which a conductive paste is used instead of a conductive film and a configuration in which the weight of the second connection target member is added to the conductive paste without applying pressure is employed in combination. It has great significance because it gets its effect at a much higher level.

Further, in WO2008 / 023452A1, it is described that, from the viewpoint of efficiently moving the solder powder to the electrode surface, the solder powder is pressed at a predetermined pressure at the time of bonding, and the pressing pressure is higher than the pressure , It is described that the pressure is 0 MPa or more, preferably 1 MPa or more, and even if the pressure which is intentionally applied to the adhesive tape is 0 MPa, the self- Pressure may be applied. In WO2008 / 023452A1, it is described that the pressure to be applied to the adhesive tape may be 0 MPa, but there is no description of the difference in the effect when the pressure exceeding 0 MPa is applied and when the pressure is 0 MPa.

If the conductive paste is used instead of the conductive film, the thickness of the connection portion can be appropriately adjusted by the application amount of the conductive paste. On the other hand, in the case of the conductive film, in order to change or adjust the thickness of the connection portion, there is a problem that a conductive film having a different thickness is prepared or a conductive film having a predetermined thickness is prepared.

Best Mode for Carrying Out the Invention Hereinafter, the present invention will be clarified by explaining specific embodiments and examples of the present invention with reference to the drawings.

First, Fig. 1 schematically shows a partially cut-away front cross-sectional view of a connection structure obtained by using a conductive paste according to an embodiment of the present invention.

The connection structure 1 shown in Fig. 1 has a structure in which a first connection target member 2, a second connection target member 3 and a first connection target member 2 and a second connection target member 3 are connected (Not shown). The connecting portion 4 is formed of a thermosetting component and a conductive paste containing a plurality of solder particles. In this conductive paste, the exothermic peak top temperature in the main curing of the thermosetting component and the endothermic peak top temperature in the melting of the solder particles satisfy the above-described relationship.

The connecting portion 4 has a soldering portion 4A in which a plurality of solder particles are gathered and joined together and a cured portion 4B in which a thermosetting component is thermally cured.

The first connection target member 2 has a plurality of first electrodes 2a on its surface (upper surface). The second connection target member 3 has a plurality of second electrodes 3a on its surface (lower surface). The first electrode 2a and the second electrode 3a are electrically connected by the soldering portion 4A. Therefore, the first connection target member 2 and the second connection target member 3 are electrically connected by the solder portion 4A. In the region (cured portion 4B) different from the soldering portion 4A gathered between the first electrode 2a and the second electrode 3a in the connecting portion 4, there is no solder. In the region different from the soldering portion 4A (the portion of the hardened portion 4B), there is no solder separated from the soldering portion 4A. If the amount is small, solder may exist in a region (cured portion 4B) different from the soldering portion 4A gathered between the first electrode 2a and the second electrode 3a.

As shown in Fig. 1, in the connection structure 1, after the plurality of solder particles are melted, the melts of the solder particles are solidified after the surface of the electrodes are widened to form the soldering portions 4A. As a result, the connection area between the solder portion 4A and the first electrode 2a, the solder portion 4A, and the second electrode 3a is increased. In other words, by using the solder particles, the solder portion 4A, the first electrode 2a, the solder portion 4A, and the solder portion 4A can be formed in the same manner as in the case of using conductive particles whose conductive outer surface is a metal such as nickel, The contact area of the second electrode 3a becomes large. As a result, conduction reliability and connection reliability in the connection structure 1 are enhanced. The conductive paste may also contain flux. In the case of using flux, the flux generally gradually deactivates by heating.

In the connection structure 1 shown in Fig. 1, all of the soldering portions 4A are located in the regions where the first and second electrodes 2a and 3a face each other. The connection structure 1X of the modified example shown in Fig. 3 is different from the connection structure 1 shown in Fig. 1 only in the connection portion 4X. The connecting portion 4X has a soldering portion 4XA and a cured portion 4XB. Most of the soldering portion 4XA is located in a region where the first and second electrodes 2a and 3a face each other and the soldering portion 4XA is partly covered by the first and second electrodes 2a and 3a, Or may be sideways from the opposed regions of the first and second plates 2a and 3a. The soldering portion 4XA that is laterally displaced from the opposing region of the first and second electrodes 2a and 3a is a part of the soldering portion 4XA and is not solder away from the soldering portion 4XA. Further, in the present embodiment, the amount of solder away from the solder portion can be reduced, but solder away from the solder portion may be present in the hardened portion.

When the usage amount of the solder particles is reduced, it is easy to obtain the connection structure 1. If the amount of solder particles used is increased, it is easy to obtain the connection structure 1X.

Next, an example of a method of manufacturing the connection structure 1 using the conductive paste according to one embodiment of the present invention will be described.

First, a first connection target member 2 having a first electrode 2a on its surface (upper surface) is prepared. 2 (a), a thermosetting component 11B and a conductive paste 11 including a plurality of solder particles 11A are formed on the surface of the first connection target member 2, (First step). The conductive paste 11 is disposed on the surface of the first connection target member 2 on which the first electrode 2a is formed. After the conductive paste 11 is disposed, the solder particles 11A are arranged on both the first electrode 2a (line) and the region where the first electrode 2a is not formed (space).

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

Furthermore, a second connection target member 3 having a second electrode 3a on its surface (lower surface) is prepared. 2 (b), in the conductive paste 11 on the surface of the first connection target member 2, the conductive paste 11 is separated from the first connection target member 2 side And the second connection target member 3 is arranged on the surface on the opposite side (second step). The second connection target member 3 is arranged on the surface of the conductive paste 11 from the second electrode 3a side. At this time, the first electrode 2a and the second electrode 3a are opposed to each other.

Subsequently, the conductive paste 11 is heated to a temperature not lower than the melting point of the solder particles 11A and not lower than the hardening temperature of the thermosetting component 11B (third step). That is, the conductive paste 11 is heated at a temperature lower than the melting point of the solder particles 11A and the curing temperature of the thermosetting component 11B. During this heating, the solder particles 11A existing in the regions where the electrodes are not formed are gathered between the first electrode 2a and the second electrode 3a (magnetic cohesion effect). In this embodiment, since the conductive paste is used instead of the conductive film, the solder particles 11A are effectively gathered between the first electrode 2a and the second electrode 3a. Further, the solder particles 11A are melted and bonded to each other. Further, the thermosetting component 11B is thermally cured. As a result, as shown in Fig. 2C, the connecting portion 4 connecting the first connection target member 2 and the second connection target member 3 is formed by the conductive paste 11 do. The connecting portion 4 is formed by the conductive paste 11 and the solder portion 4A is formed by bonding a plurality of solder particles 11A to thermally cure the thermosetting component 11B, . When the solder particles 3 move quickly, the movement of the solder particles 3 which are not positioned between the first electrode 2a and the second electrode 3a starts, and then the first electrode 2a and the second electrode 3a, The temperature may not be constantly maintained until the movement of the solder particles 3 is completed between the solder balls 3a.

In the present embodiment, no pressure is applied in the second step and the third step. In the present embodiment, the weight of the second connection target member 3 is applied to the conductive paste 11. This allows the solder particles 11A to effectively gather between the first electrode 2a and the second electrode 3a at the time of forming the connection portion 4. In addition, when the pressing is performed in at least one of the second step and the third step, the tendency that the action of the solder particles to gather between the first electrode and the second electrode is inhibited becomes high. This was discovered by the present inventors.

In addition, a preliminary heating process may be provided throughout the third process. This preliminary heating step is a step of heating the conductive paste 11 at a temperature at which the weight of the second connection target member 3 is applied and the temperature at which the thermosetting component 11B is not thermally cured at a temperature higher than the melting temperature of the solder Quot; means a step of heating for 60 seconds to 60 seconds. By providing this step, the action to be collected between the first electrode and the second electrode of the solder particles is further enhanced, and the voids that may occur between the first connection object member and the second connection object member can be suppressed have.

In this manner, the connection structure 1 shown in Fig. 1 is obtained. Further, the second step and the third step may be performed continuously. After the second step is performed, the resulting laminate of the first connection target member 2, the conductive paste 11, and the second connection target member 3 is moved to the heating portion, and the third step is performed It is possible. In order to perform the heating, the laminate may be disposed on the heating member, or the laminate may be disposed in the heated space.

The connection structures 1 and 1X are provided with the first electrode 2a and the second electrode 3a in the stacking direction of the first electrode 2a and the connection portion 4 and the second electrode 3a, (50% or more of the area 100% of the mutually facing portions of the first electrode 2a and the second electrode 3a) of the soldering portion (4A, 4B) in the connecting portions 4, 4A, and 4XA are disposed on the connection structure 1, 1X.

The heating temperature in the third step is not particularly limited as long as it is not lower than the melting point of the solder particles and is not lower than the hardening temperature of the thermosetting component. The heating temperature is preferably 130 占 폚 or higher, more preferably 160 占 폚 or higher, preferably 450 占 폚 or lower, more preferably 250 占 폚 or lower, further preferably 200 占 폚 or lower.

The temperature of the preliminary heating step is preferably 100 占 폚 or higher, more preferably 120 占 폚 or higher, further preferably 140 占 폚 or higher, preferably 160 占 폚 or lower, more preferably 150 占 폚 or lower.

The first connection target member may have at least one first electrode. It is preferable that the first connection target member has a plurality of first electrodes. The second connection target member may have at least one second electrode. The second connection target member preferably has a plurality of second electrodes.

The first and second connection target members are not particularly limited. Specifically, examples of the first and second connection target members include electronic parts such as a semiconductor chip, a capacitor and a diode, and a resin film, a printed board, a flexible printed board, a flexible flat cable, a rigid flexible board, a glass epoxy board and a glass board An electronic component such as a circuit board of a printed circuit board. It is preferable that the first and second connection target members are electronic parts.

It is preferable that at least one of the first connection target member and the second connection target member is a resin film, a flexible printed circuit board, a flexible flat cable, or a rigid flexible substrate. It is preferable that the second connection target member is a resin film, a flexible printed circuit board, a flexible flat cable, or a rigid flexible substrate. The resin film, the flexible printed circuit board, the flexible flat cable, and the rigid flexible substrate have high flexibility and relatively light weight properties. In the case of using a conductive film for connection of such members to be connected, there is a tendency that the solder particles are difficult to collect on the electrode. 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 solder particles can be efficiently collected on the electrode, Can be increased sufficiently. In the case of using a resin film, a flexible printed circuit board, a flexible flat cable, or a rigid flexible substrate, the effect of improving the conduction reliability between the electrodes by not pressing is further improved compared with the case of using other members to be connected such as semiconductor chips . The first and second connection target members may be a resin film, a flexible printed circuit board, a flexible flat cable, or a rigid flexible substrate.

Examples of the electrode formed on the member to be connected include 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. When the connection target member is a flexible printed circuit board or a flexible flat cable, the electrode is preferably a gold electrode, a nickel electrode, a tin electrode, a silver electrode, or a copper electrode. When the connection target member is a glass substrate, it is preferable that the electrode is an aluminum electrode, a copper electrode, a molybdenum electrode, a silver electrode, or a tungsten electrode. When the electrode is an aluminum electrode, it may be an electrode formed only of aluminum, or an electrode in which an aluminum layer is laminated on the surface of the metal oxide layer. Examples of the material of the metal oxide layer include indium oxide doped with a trivalent metal element and zinc oxide doped with a trivalent metal element. Examples of the trivalent metal element include Sn, Al and Ga.

The distance D1 of the connecting portion at a position where the first electrode and the second electrode face each other is preferably 1 mu m or more, more preferably 3 mu m or more, preferably 40 mu m or less, more preferably 30 Mu m or less. If the distance D1 is equal to or lower than the lower limit, the connection reliability of the connecting portion and the member to be connected becomes further higher. When the distance D1 is less than the upper limit, the solder particles are more likely to gather on the electrode at the time of forming the connection portion, and the reliability of the conduction between the electrodes is further increased. From the viewpoint of further enhancing the conduction reliability between the electrodes, the distance D1 is preferably 10 占 퐉 or more, and more preferably 12 占 퐉 or more.

In order to more effectively arrange the solder particles on the electrode, the viscosity? 1 at 25 占 폚 of the conductive paste is preferably 10 Pa · s or more, more preferably 50 Pa · s or more, further preferably 100 Pa · s or more , Preferably not more than 800 Pa · s, more preferably not more than 600 Pa · s, even more preferably not more than 500 Pa · s.

The viscosity can be appropriately adjusted depending on the type and blending amount of the compounding ingredients. In addition, the viscosity can be relatively increased by use of a filler.

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

The minimum viscosity value (minimum melt viscosity value) of the conductive paste in the temperature range of 25 占 폚 or more and the melting point of the solder particles (solder) or less is preferably 0.1 Pa · s or more, more preferably 0.2 Pa S or more, preferably 10 Pa · s or less, and more preferably 1 Pa · s or less. When the lowest value of the viscosity is not less than the lower limit and not more than the upper limit, the solder particles can be arranged more efficiently on the electrode.

The lowest value of the viscosity was measured by using a strain control 1rad, a frequency of 1 Hz, a temperature raising rate of 20 占 폚 / min, a measuring temperature range of 40 to 200 占 폚 (provided that solder And when the melting point of the particles exceeds 200 캜, the upper limit of the temperature is defined as the melting point of the solder particles). From the measurement results, the lowest value of the viscosity in the temperature range of the melting point of the solder particle or less is evaluated.

The conductive paste includes a thermosetting component and a plurality of solder particles. The thermosetting component preferably includes a curing compound (thermosetting compound) that can be cured by heating and a thermosetting agent. The conductive paste preferably includes a flux.

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

(Solder particles)

The solder particles have solder on the conductive outer surface. The solder particles are formed by solder on both the center portion and the conductive outer surface.

The solder is preferably a low melting point metal having a melting point of 450 캜 or lower. The solder particles are preferably low melting point metal particles having a melting point of 450 캜 or lower. The low melting point metal particles are particles containing a low melting point metal. The low melting point metal means a metal having a melting point of 450 캜 or lower. The melting point of the low melting point metal is preferably 300 DEG C or lower, more preferably 160 DEG C or lower. Further, the solder particles include tin. The content of tin in 100 wt% of the metal contained in the solder particles is preferably at least 30 wt%, more preferably at least 40 wt%, still more preferably at least 70 wt%, particularly preferably at least 90 wt% . When the content of tin in the solder particles is lower than the lower limit described above, connection reliability between the solder portion and the electrode is further enhanced.

The content of the tin was measured using a high frequency inductively coupled plasma emission spectrochemical analyzer ("ICP-AES" manufactured by Horiba Seisakusho Co., Ltd.) or a fluorescent X-ray analyzer ("EDX-800HS" available from Shimadzu Corporation) It is measurable.

By using the solder particles, the solder is melted and bonded to the electrode, and the solder portion conducts between the electrodes. For example, since the solder portion and the electrode are not in point contact but in surface contact, the connection resistance is lowered. In addition, by using the solder particles, the bonding strength between the solder portion and the electrode is increased. As a result, the solder portion and the electrode are less likely to be peeled off, and the conduction reliability and the connection reliability are effectively increased.

The low melting point metal constituting the solder particles is not particularly limited. The low melting point metal is preferably an alloy containing tin or tin. Examples of the alloy include tin-silver alloy, tin-copper alloy, tin-silver-copper alloy, tin-bismuth alloy, tin-zinc alloy and tin-indium alloy. Among them, it is preferable that the low melting point metal is tin, a tin-silver alloy, a tin-silver-copper alloy, a tin-bismuth alloy, and a tin-indium alloy from the viewpoint of excellent wettability to electrodes. Tin-bismuth alloy, and tin-indium alloy.

The solder particles are preferably a filler material having a liquidus temperature of 450 DEG C or less based on JIS Z3001: welding terminology. Examples of the composition of the solder particles include metal compositions including zinc, gold, silver, lead, copper, tin, bismuth, indium and the like. Among them, tin-indium based (117 ° C process) or tin-bismuth process (139 ° C process) which is a low melting point and lead-free is preferable. That is, the solder particles preferably contain no lead, and preferably contain tin and indium or contain tin and bismuth.

The solder particles may be at least one selected from the group consisting of nickel, copper, antimony, aluminum, zinc, iron, gold, titanium, phosphorus, germanium, tellurium, cobalt, bismuth, manganese, chromium, Molybdenum, palladium, and the like. From the viewpoint of further increasing the bonding strength between the solder portion and the electrode, it is preferable that the solder particles include nickel, copper, antimony, aluminum or zinc. From the viewpoint of further increasing the bonding strength between the solder portion and the electrode, the content of these metals for increasing the bonding strength is preferably 0.0001 wt% or more, and preferably 1 wt% or less, in 100 wt% of the solder particles.

The average particle diameter of the solder particles is preferably 0.5 mu m or more, more preferably 1 mu m or more, further preferably 3 mu m or more, particularly preferably 5 mu m or more, preferably 100 mu m or less, Is not more than 40 mu m, further preferably not more than 30 mu m, more preferably not more than 20 mu m, particularly preferably not more than 15 mu m, and most preferably not more than 10 mu m. When the mean particle diameter of the solder particles is not less than the lower limit and not more than the upper limit, solder particles can be arranged more efficiently on the electrode. It is particularly preferable that the average particle diameter of the solder particles is not less than 3 mu m and not more than 30 mu m.

The " average particle diameter " of the solder particles indicates the number average particle diameter. The average particle diameter of the solder particles is obtained by, for example, observing 50 pieces of arbitrary solder particles with an electron microscope or an optical microscope and calculating an average value.

The content of the solder particles in 100 wt% of the conductive paste is preferably 1 wt% or more, more preferably 2 wt% or more, still more preferably 10 wt% or more, particularly preferably 20 wt% Is not less than 30% by weight, preferably not more than 80% by weight, more preferably not more than 60% by weight, further preferably not more than 50% by weight. If the content of the solder particles is lower than or equal to the lower limit and lower than or equal to the upper limit, solder particles can be more efficiently arranged on the electrode, and more solder particles can be easily arranged between the electrodes, thereby further improving the reliability of conduction. From the viewpoint of further improving conduction reliability, the content of the solder particles is preferably large.

(Compound that can be cured by heating: a thermosetting component)

Examples of the thermosetting compound include oxetane compounds, epoxy compounds, episulfide compounds, (meth) acrylic compounds, phenol compounds, amino compounds, unsaturated polyester compounds, polyurethane compounds, silicone compounds and polyimide compounds. Among them, an epoxy compound is preferable from the viewpoint of further improving the curability and viscosity of the conductive paste and further improving the connection reliability.

The content of the thermosetting compound in 100 wt% of the conductive paste is preferably 20 wt% or more, more preferably 40 wt% or more, further preferably 50 wt% or more, preferably 99 wt% By weight, preferably not more than 98% by weight, more preferably not more than 90% by weight, particularly preferably not more than 80% by weight. From the viewpoint of further improving the impact resistance, the content of the above-mentioned thermosetting component is preferably large.

(Thermosetting agent: thermosetting component)

The thermosetting agent thermally cures the thermosetting compound. Examples of the heat curing 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 generator. The thermosetting agent may be used alone or in combination of two or more.

Among them, an imidazole curing agent, a polythiol curing agent or an amine curing agent is preferable because the conductive paste can be cured at a lower temperature more rapidly. Further, when the heat curing agent is mixed with the curable compound that can be cured by heating, the storage stability is enhanced, so that a latent 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. Further, the thermosetting agent may be coated with a high molecular substance such as a polyurethane resin or a polyester resin.

The imidazole curing agent is not particularly limited, and examples thereof include 2-methylimidazole, 2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, Imidazolium trimellitate, 2,4-diamino-6- [2'-methylimidazolyl- (1 ')] - ethyl -s- triazine and 2,4- diamino- -Methylimidazolyl- (1 ')] - ethyl-s-triazine isocyanuric acid adduct.

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

The solubility parameter of the polythiol curing agent is preferably 9.5 or more, and preferably 12 or less. The solubility parameter is calculated by the Fedors method. For example, the solubility parameter of trimethylolpropane tris-3-mercaptopropionate is 9.6 and the solubility parameter of dipentaerythritol hexa-3-mercaptopropionate is 11.4.

The amine curing agent is not particularly limited and includes hexamethylenediamine, octamethylenediamine, decamethylenediamine, 3,9-bis (3-aminopropyl) -2,4,8,10-tetaspiro [5.5] undecane, bis (4-aminocyclohexyl) methane, metaphenylenediamine, and diaminodiphenylsulfone.

Examples of the thermal cationic curing agent include an iodonium-based cationic curing agent, an oxonium-based cationic curing agent, and a sulfonium-based cationic curing agent. Examples of the iodonium-based cationic curing agent include bis (4-tert-butylphenyl) iodonium hexafluorophosphate and the like. Examples of the oxonium-based cation curing agent include trimethyloxonium tetrafluoroborate and the like. Examples of the sulfonium cation-based curing agent include tri-p-tolylsulfonium hexafluorophosphate and the like.

The heat radical generator is not particularly limited, and examples thereof include an azo compound and an organic peroxide. Examples of the azo compound include azobisisobutylonitrile (AIBN) and the like. Examples of the organic peroxide include di-tert-butyl peroxide and methyl ethyl ketone peroxide.

The reaction initiation temperature of the thermosetting agent is preferably at least 50 ° C, more preferably at least 70 ° C, more preferably at least 80 ° C, preferably at most 250 ° C, more preferably at most 200 ° C, Is 150 DEG C or less, particularly preferably 140 DEG C or less. If the reaction initiation temperature of the thermosetting agent is not less than the lower limit and not more than the upper limit, the solder particles are more efficiently arranged on the electrode. The reaction initiation temperature of the thermosetting agent is particularly preferably from 80 캜 to 140 캜.

From the viewpoint of more efficiently placing the solder on the electrode, the reaction initiation temperature of the thermosetting agent is preferably higher than the melting point of the solder in the solder particle, more preferably 5 deg. C or higher, more preferably 10 deg. C or higher Higher is more preferable.

The reaction initiation temperature of the thermosetting agent means the temperature at which the exothermic peak in the DSC starts to rise (i.e., the above-mentioned heat generation initiation temperature).

The content of the thermosetting agent is not particularly limited. The content of the thermosetting agent is preferably 0.01 parts by weight or more, more preferably 1 part by weight or more, preferably 200 parts by weight or less, more preferably 100 parts by weight or less, based on 100 parts by weight of the thermosetting compound. More preferably 75 parts by weight or less. If the content of the heat curing agent is lower than the lower limit described above, it is easy to sufficiently cure the conductive paste. If the content of the thermosetting agent is less than the upper limit, an excess of the thermosetting agent that is not involved in curing after curing is hardly left, and the heat resistance of the cured product is further increased.

(Flux)

The conductive paste preferably includes a flux. By using the flux, the solder can be arranged more effectively on the electrode. The flux is not particularly limited. As the flux, a flux generally used for solder bonding or 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, a molten salt, a phosphoric acid, a derivative of phosphoric acid, an organic halide, a hydrazine, an organic acid, The flux may be used alone or in combination of two or more.

Examples of the molten salt include ammonium chloride and the like. Examples of the organic acid include lactic acid, citric acid, stearic acid, glutamic acid and glutaric acid. Examples of the papermaking papers include activated papermaking and inactive papermaking. It is preferable that the flux is an organic acid having two or more carboxyl groups, and a feedstock. The flux may be an organic acid having two or more carboxyl groups, or may be tanned. By using an organic acid having two or more carboxyl groups and a papermaking paper, the reliability of conduction between the electrodes is further enhanced.

The above paper is a rosin mainly containing abietic acid. The flux is preferably rosin, more preferably abietic acid. By using this preferable flux, the reliability of conduction between the electrodes is further enhanced.

The melting point of the flux is preferably 50 占 폚 or higher, more preferably 70 占 폚 or higher, even more preferably 80 占 폚 or higher, preferably 200 占 폚 or lower, more preferably 160 占 폚 or lower, even more preferably 150 Lt; 0 > C, more preferably 140 < 0 > C or less. When the melting point of the flux is higher than or equal to the lower limit and lower than or equal to the upper limit, the flux effect is more effectively exhibited, and the solder particles are more efficiently arranged on the electrode. The melting point of the flux is preferably 80 ° C or higher and 190 ° C or lower. The melting point of the flux is particularly preferably from 80 캜 to 140 캜.

Examples of the flux having a melting point of 80 ° C or more and 190 ° C or less include succinic acid having a melting point of 186 ° C, glutaric acid having a melting point of 96 ° C, adipic acid having a melting point of 152 ° C, pimelic acid having a melting point of 104 ° C, 142 占 폚), benzoic acid (melting point 122 占 폚), malic acid (melting point 130 占 폚), and the like.

The boiling point of the flux is preferably 200 ° C or lower.

From the viewpoint of more efficiently placing the solder on the electrode, the melting point of the flux is preferably lower than the melting point of the solder in the solder particle, more preferably 5 deg. C or lower, more preferably 10 deg. desirable.

From the viewpoint of more efficiently placing the solder on the electrode, the melting point of the flux is preferably lower than the reaction peak of the thermosetting agent, more preferably 5 deg. C or lower, still more preferably 10 deg.

The flux may be dispersed in the conductive paste. Or may be attached on the surface of the solder particles.

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

It is preferable that the heat generation starting temperature of the thermosetting component is higher than the activation temperature (melting point) of the flux from the viewpoint of more efficiently arranging the solder particles on the electrode and further enhancing the conduction reliability between the electrodes. The endothermic peak top temperature in the melting of the solder particles is preferably higher than the activation temperature (melting point) of the flux from the viewpoint of more efficiently arranging the solder particles on the electrode and further enhancing the conduction reliability between the electrodes Do. The heat generation starting temperature of the thermosetting component is higher than the activation temperature (melting point) of the flux from the viewpoint of more efficiently arranging the solder particles on the electrode and further enhancing the conduction reliability between the electrodes, (Melting point) of the flux is preferably higher than the activation temperature (melting point) of the flux.

From the viewpoint that the solder particles are disposed more efficiently on the electrode and the reliability of conduction between the electrodes is further enhanced, the absolute value of the difference between the heat generation initiation temperature of the thermosetting component and the activation temperature (melting point) of the flux is preferably 10 DEG C or higher, more preferably 20 DEG C or higher, preferably 80 DEG C or lower, more preferably 70 DEG C or lower. From the viewpoint of more efficiently arranging the solder particles on the electrode and further enhancing the conduction reliability between the electrodes, it is preferable that the maximum value of the difference between the endothermic peak top temperature in the melting of the solder particles and the active temperature (melting point) Is preferably 1 占 폚 or higher, more preferably 20 占 폚 or higher, preferably 60 占 폚 or lower, more preferably 50 占 폚 or lower.

The content of the flux in 100 wt% of the conductive paste is preferably 0.5 wt% or more, preferably 30 wt% or less, more preferably 25 wt% or less. The conductive paste may not contain a flux. If the content of the flux is above the lower limit and below the upper limit, it is difficult to further form an oxide film on the surface of the solder and the electrode, and furthermore, the oxide film formed on the surface of the solder and the electrode can be removed more effectively.

(Other components)

The conductive paste may contain 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 be included.

Hereinafter, the present invention will be described in detail with reference to examples and comparative examples. The present invention is not limited to the following examples.

Polymer A:

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

72 parts by weight of bisphenol F (containing 4,4'-methylene bisphenol and 2,4'-methylene bisphenol and 2,2'-methylene bisphenol in a weight ratio of 2: 3: 1), 1,6-hexane diol diglyme , 70 parts by weight of cidyl ether and 30 parts by weight of bisphenol F type epoxy resin (EPICLON EXA-830CRP, manufactured by DIC) were put in a three-necked flask and dissolved at 150 캜 under a nitrogen flow. Thereafter, 0.1 part by weight of tetra-n-butylsulfonium bromide as an addition reaction catalyst between a hydroxyl group and an epoxy group was added and an addition polymerization reaction was conducted at 150 占 폚 for 6 hours under a nitrogen flow to obtain a reaction product (polymer A).

NMR confirmed that the addition polymerization reaction had proceeded and that the reaction product (polymer A) had a structure unit in which the hydroxyl group derived from bisphenol F and the epoxy group of 1,6-hexanediol diglycidyl ether and bisphenol F type epoxy resin were bonded In the main chain, and had epoxy groups at both ends.

The weight average molecular weight of the reactant (polymer A) obtained by GPC was 10,000, and the number average molecular weight was 3,500.

Polymer B: Epoxy rigid skeleton phenoxy resin at both ends, "YX6900BH45" manufactured by Mitsubishi Chemical Corporation, weight average molecular weight of 16,000

Thermosetting compound 1: resorcinol-type epoxy compound, "EX-201" manufactured by Nagase Chemtex Co.,

Thermosetting compound 2: naphthalene type epoxy compound "HP-4032D" manufactured by DIC

Thermosetting compound 3: bisphenol F type epoxy resin, "EVA-830CRP" manufactured by DIC Corporation

Thermal curing agent: pentaerythritol tetrakis (3-mercaptobutyrate), "CALENS MT PE1" manufactured by Showa Denko KK

Flux 1: glutaric acid, manufactured by Wako Pure Chemical Industries, Ltd.

Flux 2: Adipic acid, manufactured by Wako Pure Chemical Industries, Ltd.

Latent epoxy thermosetting agent: "Fuji Cure 7000" manufactured by T & KTOKA

Latent heat curing agent: microcapsule type, "HXA-3932HP" manufactured by Asahi Chemical Industries, Ltd.

Solder particles 1: Sn-58Bi solder particles, melting point 139 占 폚, "10-25" manufactured by Mitsui Kinzoku Kogyo Co., average particle diameter 10 m

Solder particles 2: Sn-37Pb solder particles, melting point 183 DEG C, "10-25" manufactured by Mitsui Kinzoku Kogyo Co., average particle diameter 12 mu m

Solder Particle 3:

200 g of solder powder, 40 g of adipic acid and 70 g of acetone were weighed into a three-necked flask, and 0.3 g of dibutyltin oxide, which is a dehydration condensation catalyst of hydroxyl group on the surface of the solder powder and carboxyl group of glutaric acid, And reacted for 4 hours. Thereafter, the solder powder was collected by filtration.

The solder powder, 50 g of glutaric acid, 200 g of toluene, and 0.3 g of para-toluenesulfonic acid were weighed into a three-necked flask, and reacted at 120 ° C for 3 hours while evacuation and refluxing. At this time, a Dean Stark extraction apparatus was used to carry out the reaction while removing water produced by dehydration condensation.

Thereafter, the solder powder was recovered by filtration, washed with hexane, and dried. Thereafter, the resulting solder powder was milled with a ball mill, and a sieve was selected to have a predetermined CV value to obtain solder particles 3.

Conductive particle 1: A copper layer having a thickness of 1 占 퐉 was formed on the surface of the resin particle, and a solder layer (tin: bismuth = 42 wt%: 58 wt%) having a thickness of 3 占 퐉 was formed on the surface of the copper layer Conductive particle

Method of Making Conductive Particle 1:

Divinylbenzene resin particles having an average particle diameter of 10 占 퐉 ("Micropearl SP-210" manufactured by Sekisui Chemical Co., Ltd.) were electroless nickel plated to form a ground nickel plating layer having a thickness of 0.1 占 퐉 on the surface of the resin particles. Subsequently, resin particles having a base nickel plated layer formed thereon were electroplated with copper to form a copper layer having a thickness of 1 탆. Further, electrolytic plating was performed using an electrolytic plating solution containing tin and bismuth to form a solder layer having a thickness of 3 탆. Thus, a 1 mu m thick copper layer was formed on the surface of the resin particles, and a solder layer (tin: bismuth = 42 wt%: 58 wt%) having a thickness of 3 mu m was formed on the surface of the copper layer Conductive particles 1 were produced.

A phenoxy resin ("YP-50S" manufactured by Shinnitetsu Sumikin Kagaku Co., Ltd.)

(Examples 1 to 10, 12 and 13)

(1) Fabrication of anisotropic conductive paste

The components shown in the following Table 1 were compounded in the amounts shown in Table 1 below to obtain an anisotropic conductive paste.

(2) Fabrication of first connection structure (L / S = 50 탆 / 50 탆)

A glass epoxy substrate (FR-4 substrate) (first connection target member) having a copper electrode pattern (copper electrode thickness 10 mu m) having an L / S of 50 mu m / 50 mu m on its upper surface was prepared. A flexible printed circuit board (second connection target member) having a copper electrode pattern (copper electrode thickness 10 占 퐉) having L / S of 50 占 퐉 / 50 占 퐉 was prepared.

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

An anisotropic conductive paste immediately after fabrication was coated on the upper surface of the glass epoxy substrate to a thickness of 50 m to form an anisotropic conductive paste layer. Subsequently, the flexible printed circuit board was laminated on the upper surface of the anisotropic conductive paste layer such that the electrodes were opposed to each other. At this time, no pressure was applied. The weight of the flexible printed circuit board is applied to the anisotropic conductive paste layer. Thereafter, the solder was melted while heating so that the temperature of the anisotropic conductive paste layer was 185 占 폚, and the anisotropic conductive paste layer was cured at 185 占 폚 to obtain a first connection structure.

(3) Fabrication of second connection structure (L / S = 75 mu m / 75 mu m)

A glass epoxy substrate (FR-4 substrate) (first connection target member) having a copper electrode pattern (copper electrode thickness 10 占 퐉) having an L / S of 75 占 퐉 / 75 占 퐉 on the upper surface was prepared. Further, a flexible printed circuit board (second connection target member) having a copper electrode pattern (copper electrode thickness 10 占 퐉) having L / S of 75 占 퐉 / 75 占 퐉 was prepared.

A second connection structure was obtained in the same manner as in the production of the first connection structure except that the glass epoxy substrate and the flexible printed substrate differing in L / S were used.

(4) Fabrication of third connection structure (L / S = 100 mu m / 100 mu m)

A glass epoxy substrate (FR-4 substrate) (first connection target member) having a copper electrode pattern (copper electrode thickness of 10 mu m) having an L / S of 100 mu m / 100 mu m on its upper surface was prepared. Further, a flexible printed circuit board (second connection target member) having a copper electrode pattern (copper electrode thickness 10 占 퐉) having L / S of 100 占 퐉 / 100 占 퐉 was prepared.

A third connection structure was obtained in the same manner as in the production of the first connection structure except that the glass epoxy substrate and the flexible printed substrate differing in L / S were used.

(Example 11)

(One for the first connection structure), and the electrode size / the space between the electrodes is 100 m / 100 m (for the third connection structure), 75 m / 75 m (for the second connection structure), and 50 m / (Size: 30 mm × 30 mm thickness: 0.4 mm) having a square semiconductor chip (thickness: 400 μm) having a width of 5 mm and an opposing electrode were used as the first and second semiconductor chips , Thereby obtaining a third connection structure.

(Comparative Examples 1 to 3 and 6)

(1) Fabrication of anisotropic conductive paste

The components shown in the following Table 2 were compounded in the amounts shown in Table 2 below to obtain an anisotropic conductive paste. The first, second and third connection structures were obtained in the same manner as in Example 1 except that the obtained anisotropic conductive paste was used.

(Comparative Example 4)

10 parts by weight of a phenoxy resin ("YP-50S" manufactured by Shinnitetsu Sumikin Chemical Co., Ltd.) was dissolved in methyl ethyl ketone (MEK) to a solid content of 50% by weight to obtain a dissolution solution. Components other than the phenoxy resin shown in Table 2 below were blended in the amounts shown in Table 2 below and the total amount of the above solution and stirred for 5 minutes at 2000 rpm using a planetary stirrer and dried using a bar coater (Polyethylene terephthalate) film so as to have a thickness of 30 占 퐉. By vacuum drying at room temperature, MEK was removed to obtain an anisotropic conductive film.

The first, second and third connection structures were obtained in the same manner as in Example 1 except that the anisotropic conductive film was used.

(Comparative Example 5)

(Copper electrode thickness) of L / S of 100 탆 / 100 탆 (for the third connection structure), 75 탆 / 75 탆 (for the second connection structure), 50 탆 / 10 mu m) on the underside was prepared.

The first, second, and third connection structures were obtained in the same manner as in Comparative Example 1 except that the flexible printed circuit board was changed to a semiconductor chip.

(evaluation)

(1) Viscosity

The viscosity? 1 at 25 占 폚 of the anisotropic conductive paste was measured under the conditions of 25 占 폚 and 5 rpm using an E-type viscometer (manufactured by Toki Sangyo Co., Ltd.).

(2) Minimum melt viscosity

The lowest melt viscosity of the anisotropic conductive paste was measured in the temperature range from 25 占 폚 to the melting point of the solder particles or the surface solder melting point of the conductive particles.

(3) Measurement of exothermic peak P1 and endothermic peak P2 by DSC

The thermosetting components in the anisotropic conductive paste of Examples and Comparative Examples were blended. The exothermic peak P1 in the final curing of the thermosetting component was measured by heating the obtained thermosetting component at a heating rate of 10 DEG C / minute by using a differential scanning calorimeter ("Q2000" manufactured by TA Instruments).

Further, the solder particles were heated at a heating rate of 10 DEG C / minute using a differential scanning calorimeter ("Q2000" manufactured by TA Instruments), and the heat absorption peaks P2 in the melting of the solder particles were measured.

In the following Tables 1 and 2, 1) an exothermic peak top temperature P1t in the main curing of the thermosetting component, 2) an endothermic peak top temperature P2t in melting of the solder particles, and 3) And 4) an endothermic initiation temperature in the melting of the solder particles.

(4) Distance of connection (distance between electrodes)

The obtained first connection structure was observed by a section to evaluate the distance D1 (interval between the electrodes) of the connection portion at positions where the upper and lower electrodes face each other.

(5) Arrangement accuracy of solder on electrodes

In the cross section (cross section in the direction shown in Fig. 1) of the obtained first, second and third connection structures, the area of the solder remaining in the cured product away from the soldering portion disposed between the electrodes of 100% (%). In addition, the average of areas in five sections was calculated. The placement accuracy of the solder on the electrode was determined based on the following criteria.

[Criteria for determination of placement accuracy of solder on electrodes]

0: The area of the solder (solder particles) remaining in the cured product away from the soldering portion disposed between the electrodes of 100% of the total area of the solder shown on the cross section is 0%

: The area of the solder (solder particles) remaining in the cured product separated from the soldering portion disposed between the electrodes of 100% of the total area of the solder shown on the cross section exceeds 0% to 10%

DELTA: area of the solder (solder particles) remaining in the cured product away from the soldering portion disposed between the electrodes of 100% of the total area of the solder appearing on the cross section is more than 10% but not more than 30%

: Area of the solder (solder particles) remaining in the cured product away from the soldering portion disposed between the electrodes of 100% of the total area of the solder appearing on the cross section exceeds 30%

(5) Reliability of conduction between the upper and lower electrodes

In the obtained first, second and third connection structures (n = 15), the connection resistance between the upper and lower electrodes was measured by the four-terminal method. And the average value of the connection resistance was calculated. From the relationship of voltage = current x resistance, the connection resistance can be obtained by measuring the voltage when a constant current is passed. The conduction reliability was judged based on the following criteria.

[Criteria for reliability of conduction]

○○: Average value of connection resistance is 8.0Ω or less

O: Average value of connection resistance exceeds 8.0? 10.0?

?: Average value of connection resistance exceeds 10.0? 15.0?

X: Average value of connection resistance exceeds 15.0?

(6) Insulation reliability between adjacent electrodes

In the obtained first, second and third connection structures (n = 15), after being left for 100 hours in an atmosphere at a temperature of 85 캜 and a humidity of 85%, 5 V was applied between adjacent electrodes, Respectively. The insulation reliability was judged based on the following criteria.

[Judgment Criteria of Insulation Reliability]

○○: Average value of connection resistance is more than 10 ⁷ Ω

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

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

X: Average value of 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 Comparative Example 1 and the difference between the results of Example 11 and Comparative Example 5, it can be seen that, in the case where the second connection target member is a flexible printed board, It can be seen that the effect of improving the conduction reliability according to the use of the conductive paste of the present invention is even more effectively obtained.

The same was true when a resin film, a flexible flat cable, and a rigid flexible substrate were used in place of the flexible printed substrate.

Further, in the connection structures obtained in Examples 1 to 14, when the mutually opposing portions of the first electrode and the second electrode in the stacking direction of the first electrode, the connection portion and the second electrode are observed, The solder portion in the connection portion was disposed at 50% or more of the area 100% of the portions facing each other.

5 (a) and 5 (b) show an example of a connection structure using the conductive paste included in the embodiment of the present invention. Figures 5 (a) and 5 (b) are sectional images. 5 (a) and 5 (b), it can be seen that the solder (solder particles) remaining in the hardened product does not exist apart from the soldering portion disposed between the electrodes.

6 (a), 6 (b) and 6 (c) show an example of a connection structure using conductive paste not included in the embodiment of the present invention. Figs. 6 (a) and 6 (b) are sectional views, and Fig. 6 (c) is a planar image. 6 (a), 6 (b) and 6 (c), it can be seen that a plurality of solder (solder particles) remaining in the cured product away from the soldering portion disposed between the electrodes exists on the side of the soldering portion . Further, it was confirmed that, in the step of forming the connecting portion, the same connecting structure as that of the connecting structure shown in Figs. 6A, 6B and 6C was obtained even when the pressing was performed.

1, 1X ... Connection structure
2… The first connection object member
2a ... The first electrode
3 ... The second connection object member
3a ... The second electrode
4, 4X ... Connection
4A, 4XA ... Soldering portion
4B, 4XB ... Hardened portion
11 ... Conductive paste
11A ... Solder particles
11B ... Thermosetting component

Claims (13)

A thermosetting component, and a plurality of solder particles,
The exothermic peak top temperature in the main curing of the thermosetting component in the melting of the solder particles when heating the thermosetting component and the solder particles at a heating rate of 10 ° C / Wherein a maximum value of a difference between an exothermic peak top temperature in final curing of the thermosetting component and an endothermic peak top temperature in melting of the solder particles is 10 ° C or higher and 70 ° C or lower, . The method according to claim 1, wherein, when the thermosetting component and the solder particles are heated at a temperature raising rate of 10 캜 / minute to measure the differential scanning calorie, the exothermic initiation temperature of the thermosetting component And the absolute value of the difference between the heat generation starting temperature of the thermosetting component and the endothermic peak top temperature in the melting of the solder particles is 5 占 폚 or more and 50 占 폚 or less. 3. The method of claim 1 or 2,
Wherein the exothermic peak top temperature in the final curing of the thermosetting component is higher than the active temperature of the flux when the thermosetting component is heated at a heating rate of 10 캜 / min to perform a differential scanning calorimetry. 3. The method of claim 1 or 2,
Wherein the solder particles are heated at a temperature raising rate of 10 캜 / minute to measure a differential scanning calorie, wherein an endothermic peak top temperature in the melting of the solder particles is higher than an active temperature of the flux. 3. The method of claim 1 or 2,
The exothermic peak top temperature in the main curing of the thermosetting component is higher than the active temperature of the flux when the differential scanning calorie is measured by heating the thermosetting component and the solder particles at a heating rate of 10 ° C / And the endothermic peak top temperature in the melting of the solder particles is higher than the active temperature of the flux. The conductive paste according to any one of claims 1 to 5, wherein the content of the solder particles in 100 wt% of the conductive paste is 10 wt% or more and 70 wt% or less. The conductive paste according to any one of claims 1 to 6, wherein the viscosity at 25 캜 is 10 Pa · s or more and 800 Pa · s or less. The conductive paste according to any one of claims 1 to 7, wherein the lowest value of the viscosity in the temperature range below the melting point of the solder particles is 0.1 Pa · s or more and 10 Pa · s or less. A first connection target member having at least one first electrode on its surface,
A second connection target member having at least one second electrode on its surface,
And a connecting portion connecting the first connection target member and the second connection target member,
Wherein the connecting portion is formed by the conductive paste according to any one of claims 1 to 8,
Wherein the first electrode and the second electrode are electrically connected by a solder portion in the connection portion. The connection structure according to claim 9, wherein the second connection target member is a resin film, a flexible printed circuit board, a flexible flat cable, or a rigid flexible substrate. 9. A method of manufacturing a semiconductor device, comprising the steps of: disposing the conductive paste on a surface of a first connection target member having at least one first electrode on a surface thereof using the conductive paste according to any one of claims 1 to 8;
A second connection target member having at least one second electrode on its surface on a surface opposite to the first connection target member side of the conductive paste is arranged so that the first electrode and the second electrode face each other The process,
The connection portion connecting the first connection target member and the second connection target member is formed by the conductive paste by heating the conductive paste at a temperature equal to or higher than the melting point of the solder particles and not lower than a curing temperature of the thermosetting component, And electrically connecting the first electrode and the second electrode to each other by a soldering portion of the connection portion. The method according to claim 11, wherein in the step of disposing the second connection target member and the step of forming the connection part, the weight of the second connection object member is applied to the conductive paste without applying pressure, Gt; The method of manufacturing a connection structure according to claim 11 or 12, wherein the second connection target member is a resin film, a flexible printed substrate, a flexible flat cable, or a rigid flexible substrate.

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