JP6514615B2 - Method of manufacturing connection structure - Google Patents

Description

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

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

  The anisotropic conductive material is, for example, a connection between a flexible printed substrate and a glass substrate (FOG (Film on Glass)) and a connection between a semiconductor chip and a flexible printed substrate (COF (COF) to obtain various connection structures. It is used for chip on film), connection between semiconductor chip and glass substrate (COG (chip on glass)), connection between flexible printed circuit board and glass epoxy substrate (FOB (film on board)), and the like.

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

  As an example of the anisotropic conductive material, Patent Document 1 below contains a resin layer containing a thermosetting resin, a solder powder, and a curing agent, and the solder powder and the curing agent are the resin layer. An adhesive tape is disclosed therein. The adhesive tape is in the form of a film, not in the form of paste.

  Further, Patent Document 1 discloses a bonding method using the above-mentioned adhesive tape. Specifically, a first substrate, an adhesive tape, a second substrate, an adhesive tape, and a third substrate are laminated in this order from the bottom to obtain a laminate. 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 are opposed to each other. Then, the laminate is heated at a predetermined temperature and adhered. Thereby, a connection structure is obtained.

WO2008 / 023452A1

  The adhesive tape described in Patent Document 1 is in the form of a film, not in the form of paste. For this reason, it is difficult to arrange solder powder efficiently on an electrode (line). For example, in the adhesive tape described in Patent Document 1, part of the solder powder is likely to be disposed also in the area (space) where the electrode is not formed. The solder powder disposed in the area where the electrodes are not formed does not contribute to the conduction between the electrodes.

  Moreover, even if it is an anisotropic conductive paste containing solder powder, solder powder may not be efficiently arrange | positioned on an electrode (line).

  Furthermore, conventionally, in the case of using an anisotropic conductive paste containing solder powder, if a member provided with a conventional electrode is used, the laterally adjacent electrodes which should not be connected are electrically connected by solder It was discovered by the present inventors that there is a problem of being easy to do.

  The object of the present invention is that the solder particles can be efficiently arranged between the electrodes, the conduction reliability between the electrodes can be enhanced, and the insulation reliability between the electrodes which should not be connected can be enhanced. A method of manufacturing a structure is provided.

  According to a broad aspect of the present invention, a conductive paste containing a thermosetting component and a plurality of solder particles, and a first connection target member having a plurality of first electrodes having a length direction and a width direction on the surface And disposing the conductive paste on the surface of the first connection target member using a second connection target member having on the surface a plurality of second electrodes having a length direction and a width direction. And disposing the second connection target member such that the first electrode and the second electrode face each other on the surface of the conductive paste opposite to the first connection target member. And the connection connecting the first connection target member and the second connection target member by heating the conductive paste to a temperature higher than the melting point of the solder particles and higher than a curing temperature of the thermosetting component. Part is formed of the conductive paste, and Electrically connecting the first electrode and the second electrode by the solder portion in the connection portion, wherein a length direction of the first electrode as the first connection target member Use a first connection target member whose end does not reach the end of the first connection target member in a portion facing the second connection target member, or the second connection target member As the second end of the second electrode in the longitudinal direction, the second connection target member in which the end portion of the second connection target member does not reach the end portion of the portion facing the first connection target member , A method of manufacturing a connection structure is provided.

  In a specific aspect of the method of manufacturing a connection structure according to the present invention, the distance between the end in the longitudinal direction of the first electrode and the end of the first connection target member is equal to that of the first electrode. The distance between the end in the longitudinal direction of the second electrode and the end of the second connection target member is larger than the electrode width of the second electrode.

  In a specific aspect of the method of manufacturing a connection structure according to the present invention, the distance between the end in the longitudinal direction of the first electrode and the end of the first connection target member is 50 μm to 1000 μm. Or the distance between the end in the longitudinal direction of the second electrode and the end of the second connection target member is not less than 50 μm and not more than 1000 μm.

  In a specific aspect of the method of manufacturing a connection structure according to the present invention, the distance between the end in the lengthwise direction of the first electrode and the end of the first connection target member is the average particle size of the solder particles. The distance between the end of the second electrode in the lengthwise direction and the end of the second connection target member is the average particle diameter of the solder particles 5 times or more and 100 times or less.

  In a specific aspect of the method of manufacturing a connection structure according to the present invention, the first electrode has a distance between an end in a longitudinal direction of the first electrode and an end of the first connection target member. Of the distance between the end of the second electrode in the longitudinal direction and the end of the second connection target member, The ratio of 2 to the electrode width is 0.1 or more and 10 or less.

In a specific aspect of the method of manufacturing a connection structure according to the present invention, an end in a longitudinal direction of the first electrode is opposed to the second connection target member as the first connection target member. The first connection target member which does not reach the end of the first connection target member of the portion where the end of the second electrode in the lengthwise direction is used as the second connection target member, A second connection target member that does not reach the end of the second connection target member in a portion facing the first connection target member is used.

  In a specific aspect of the method of manufacturing a connection structure according to the present invention, in the step of arranging the second connection target member and the step of forming the connection portion, no pressure is applied, and the conductive paste is Pressurization is performed in at least one of the step of adding the weight of the second connection target member or the step of arranging the second connection target member and the step of forming the connection portion, and The pressure of pressurization is less than 1 MPa in both the step of arranging the second connection target member and the step of forming the connection portion.

  In a specific aspect of the method of manufacturing a connection structure according to the present invention, in the step of arranging the second connection target member and the step of forming the connection portion, no pressure is applied, and the conductive paste is The weight of the second connection target member is added.

  In a specific aspect of the method of manufacturing a connection structure according to the present invention, the average particle diameter of the solder particles is 0.5 μm or more and 100 μm or less.

  In a specific aspect of the method for manufacturing a connection structure according to the present invention, the content of the solder particles in the conductive paste is 10% by weight or more and 80% by weight or less.

  In a specific aspect of the method of manufacturing a connection structure according to the present invention, the second connection target member is a resin film, a flexible printed circuit, a rigid flexible substrate or a flexible flat cable.

  In a specific aspect of the method of manufacturing a connection structure according to the present invention, the electrode width of the first electrode is 50 μm or more and 1000 μm or less, and the electrode width of the second electrode is 50 μm or more and 1000 μm or less The inter-electrode width of the first electrode is 50 μm or more and 1000 μm or less, and the inter-electrode width of the second electrode is 50 μm or more and 1000 μm or less.

  A method of manufacturing a connection structure according to the present invention is a first connection having a conductive paste containing a thermosetting component and a plurality of solder particles, and a plurality of first electrodes having a length direction and a width direction on the surface. The conductive paste is disposed on the surface of the first connection target member using the target member and the second connection target member having the plurality of second electrodes having the length direction and the width direction on the surface. And the second connection target member such that the first electrode and the second electrode face each other on the surface opposite to the first connection target member side of the conductive paste. The first connection object member and the second connection object member are connected by heating the conductive paste at a temperature higher than the melting point of the solder particles and higher than the curing temperature of the thermosetting component. Connection part formed by the above conductive paste And the step of electrically connecting the first electrode and the second electrode by the solder portion in the connection portion, and the first connection target member further includes: Use the first connection target member in which the end in the longitudinal direction of the electrode does not reach the end of the first connection target member in a portion facing the second connection target member, or As a second connection target member, a second end of the second electrode in the lengthwise direction does not reach an end of the second connection target member in a portion opposed to the first connection target member. Since the connection target member is used, the solder particles can be efficiently arranged between the electrodes, the conduction reliability between the electrodes can be enhanced, and the insulation reliability between the electrodes which should not be connected can be enhanced. .

1 (a) and 1 (b) are a front sectional view and a partially cutaway plan view schematically showing a connection structure obtained by the method for producing a connection structure according to an embodiment of the present invention. FIG.2 (a)-(c) are front sectional drawings for demonstrating each process of the manufacturing method of the connection structure which concerns on one Embodiment of this invention. FIG. 3 is a front sectional view showing a modified example of the connection structure. FIGS. 4A and 4B are a front cross-sectional view and a partially cutaway plan view showing a conventional connection structure obtained by the conventional method of manufacturing a connection structure.

  Hereinafter, the present invention will be described in detail.

  In the method for manufacturing a connection structure according to the present invention, a first connection having on the surface a conductive paste containing a thermosetting component and a plurality of solder particles, and a plurality of first electrodes having a length direction and a width direction. A target member and a second connection target member having a plurality of second electrodes having a length direction and a width direction on the surface are used.

  In the method for manufacturing a connection structure according to the present invention, the step of disposing the conductive paste on the surface of the first connection target member and the surface opposite to the first connection target member side of the conductive paste. Arranging the second connection target member such that the first electrode and the second electrode face each other, a melting point of the solder particles or more and a curing temperature of the thermosetting component or more Forming the connection portion connecting the first connection target member and the second connection target member with the conductive paste by heating the conductive paste; and Electrically connecting the second electrode with the solder portion in the connection portion.

  In the method of manufacturing a connection structure according to the present invention, as the first connection target member, the end portion of the first electrode in the length direction is a portion of the portion facing the second connection target member. Either the first connection target member not reaching the end of the first connection target member is used, or, as the second connection target member, the end of the second electrode in the longitudinal direction is the first connection target member. The second connection target member that does not reach the end of the second connection target member in the portion facing the connection target member is used.

  If the end in the longitudinal direction of the first electrode does not reach the end of the first connection target member in a portion facing the second connection target member, the first electrode is provided. An unoccupied area is present laterally to the longitudinal end of the first electrode. When the end in the lengthwise direction of the second electrode does not reach the end of the second connection target member in a portion opposed to the first connection target member as the second connection target member That is, the area where the second electrode is not provided is present more laterally than the longitudinal end of the second electrode.

  In the method of manufacturing a connection structure according to the present invention, since the above configuration is adopted, the insulation reliability between laterally adjacent electrodes which should not be connected can be enhanced. This is because, when the electrode reaches the end of the connection target member, when the solder particles are moved by heating, the solder particle wraps around the end of the connection target member, and the solder particle is near the end of the electrode In the case where the solder particles are moved by heating when the electrodes are arranged so that the electrodes adjacent in the lateral direction are easily electrically connected by the solder while the electrodes do not reach the end of the connection target member, It is difficult for the solder particles to wrap around near the end of the target member, and the solder particles will flow more laterally than the end of the electrode near the end of the electrode. It is because it is hard to be connected.

Furthermore, in the method for manufacturing a connection structure according to the present invention, since the above configuration is adopted, a large number of solder particles gather between each electrode, and the plurality of solder particles are efficiently placed on the electrodes (lines). It can be arranged. Further, some of the plurality of solder particles are difficult to be disposed in the region (space) in which the electrode is not formed, and the amount of solder particles disposed in the region in which the electrode is not formed can be considerably reduced. Therefore, the conduction reliability between the electrodes can be enhanced. Moreover, electrical connection between laterally adjacent electrodes, which should not be connected, can be prevented, and insulation reliability can be enhanced.

  In the present invention, other methods of efficiently collecting a plurality of solder particles between the electrodes may be further adopted. As a method of efficiently collecting a plurality of solder particles between electrodes, when heat is applied to the conductive paste between the first connection target member and the second connection target member, the viscosity of the conductive paste is generated by the heat The method of making the convection of the electrically conductive paste between a 1st connection object member and a 2nd connection object member generate | occur | produce, etc. are mentioned. In this method, a method of generating convection by the difference in heat capacity between an electrode on the surface of the connection target member and the other surface members, a method of generating the convection by using water vapor of the water of the connection target member as heat, and the first The method etc. which generate | occur | produce a convection with the temperature difference of a connection object member and a 2nd connection object member are mentioned. Thereby, the solder particles in the conductive paste can be efficiently moved to the surface of the electrode.

  In the present invention, a method of selectively agglomerating solder particles on the surface of the electrode may be further employed. As a method of selectively aggregating solder particles on the surface of an electrode, a connection target member formed of an electrode material having good wettability of melted solder particles and another surface material having poor wettability of melted solder particles Selected, the melted solder particles that have reached the surface of the electrode are selectively attached to the electrode, and another solder particle is melted and attached to the melted solder particles, an electrode material with good thermal conductivity By selecting the connection target member formed of the other surface materials with poor thermal conductivity and applying heat, the temperature of the electrode is made higher than that of the other surface member, thereby selectively on the electrode. Method of melting the solder by the method, solder particles selectively condensed on the electrode using the solder particles treated to have a positive charge with respect to the negative charge present on the electrode formed of metal Method of, and, the electrode having a hydrophilic metal surface, the resin other than the solder particles in the conductive paste by a hydrophobic, a method to aggregate selectively solder particles on the electrode, and the like.

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

  In the method of manufacturing a connection structure according to the present invention, no pressure is applied in the step of arranging the second connection target member and the step of forming the connection portion, and the second connection is performed on the conductive paste. Pressing is performed in at least one of the step of adding the weight of the target member or the step of arranging the second connection target member and the step of forming the connection portion, and the second connection target member It is preferable that the pressure of pressurization is less than 1 MPa in both the step of arranging and the step of forming the connection portion. By not applying a pressure of 1 MPa or more, aggregation of the solder particles is considerably promoted. From the viewpoint of suppressing the warping of the connection target member, in the method of manufacturing a connection structure according to the present invention, at least one of the step of arranging the second connection target member and the step of forming the connection portion The pressure of pressurization may be less than 1 MPa in both the step of applying pressure and the step of arranging the second connection target member and the step of forming the connection portion. When pressing is performed, pressing may be performed only in the step of arranging the second connection target member, or may be performed only in the step of forming the connection portion. In both the step of arranging the connection target member and the step of forming the connection portion, pressurization may be performed. The pressure of less than 1 MPa includes the case where the pressure is not applied. When pressurization is performed, the pressure of pressurization is preferably 0.9 MPa or less, more preferably 0.8 MPa or less. When the pressure of pressure is 0.8 MPa or less, the aggregation of the solder particles is more significantly promoted as compared to the case where the pressure of pressure exceeds 0.8 MPa.

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

  Thus, in order to efficiently dispose the plurality of solder particles on the electrode and considerably reduce the amount of solder particles disposed in the region where the electrode is not formed, the conductive paste is used instead of the conductive film. The inventor has found that it is necessary to use.

  Furthermore, in the step of arranging the second connection target member and the step of forming the connection portion, the connection portion is not pressurized when the weight of the second connection target member is added to the conductive paste. The solder particles arranged in the region (space) in which the electrode is not formed before being formed are more likely to be collected between the first electrode and the second electrode, and the plurality of solder particles are arranged in the electrode (line) The inventors have also found that the above can be arranged more efficiently. In the present invention, a combination of a configuration using a conductive paste, not a conductive film, and a configuration without applying pressure and adding the weight of the second connection target member to the conductive paste is adopted. There is great significance in order to obtain the effects of the present invention at a higher level.

  WO 2008/023452 A1 describes that it is preferable to press with a predetermined pressure at the time of bonding from the viewpoint of pushing solder powder to the electrode surface and moving it efficiently, and the pressing pressure further secures the solder area. In the viewpoint of forming it, for example, 0 MPa or more, preferably 1 MPa or more is described, and further, even if the pressure intentionally applied to the adhesive tape is 0 MPa, It is described that the adhesive tape may be subjected to a predetermined pressure by its own weight. Although it is described in WO 2008/023452 A1 that the pressure intentionally applied to the adhesive tape may be 0 MPa, any difference in the effect between the case where the pressure exceeds 0 MPa and the case where the pressure is made 0 MPa is considered Not listed. Moreover, WO2008 / 023452A1 does not recognize at all the importance of using a non-film-like, paste-like conductive paste.

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

  Hereinafter, the present invention will be clarified by describing specific embodiments and examples of the present invention with reference to the drawings.

  First, FIGS. 1A and 1B schematically show a connection structure obtained by the method of manufacturing a connection structure according to an embodiment of the present invention in a front cross-sectional view and a partially cutaway plan view. Fig.1 (a) is front sectional drawing in alignment with the II line in FIG.1 (b).

  The connection structure 1 shown in FIG. 1 is a connection in which the first connection target member 2, the second connection target member 3, and the first connection target member 2 and the second connection target member 3 are connected. And 4 are provided. The connection portion 4 is formed of a conductive paste containing a thermosetting component and a plurality of solder particles. The connection portion 4 is a cured product of the conductive paste.

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

  The first connection target member 2 has a plurality of first electrodes 2a on the surface (upper surface). The first electrode 2a has a length direction and a width direction. In the first connection target member 2, the end in the longitudinal direction of the first electrode 2 a does not reach the end of the first connection target member 2 in a portion facing the second connection target member 3.

  The second connection target member 3 has a plurality of second electrodes 3a on the surface (lower surface). The second electrode 3a has a length direction and a width direction. The end in the longitudinal direction of the second electrode 3 a does not reach the end of the second connection target member 3 in a portion facing the first connection target member 2. The longitudinal direction of the first electrode 2a corresponds to the longitudinal direction of the second electrode 3a. The width direction of the first electrode 2a corresponds to the width direction of the second electrode 3a.

  In FIGS. 1A and 1B, although four first and second electrodes 2a and 3a are formed for convenience of illustration, generally, the number of electrodes is more than four.

  In the present invention, as the first connection target member, the end portion of the first connection target member in a portion where the end in the lengthwise direction of the first electrode is opposed to the second connection target member The first connection target member which has not been reached, or the second connection target member, a portion in which the end in the lengthwise direction of the second electrode is opposed to the first connection target member The second connection target member not reaching the end of the second connection target member is used. From the viewpoint of further enhancing the insulation reliability, the end in the longitudinal direction of the first electrode is opposed to the second connection target member as the first connection target member to which the conductive paste is applied. It is preferable to use a first connection target member which does not reach the end of the first connection target member of the portion. From the viewpoint of further enhancing the insulation reliability, as the first connection target member, the first end of the first electrode in the lengthwise direction is the first portion of the portion opposed to the second connection target member. The first connection target member which does not reach the end of the connection target member, and the second connection target member, the end in the lengthwise direction of the second electrode is the first connection target It is preferable to use a second connection target member which does not reach the end of the second connection target member in a portion facing the member.

  The first electrode 2a and the second electrode 3a are electrically connected by the solder portion 4A. Therefore, the first connection target member 2 and the second connection target member 3 are electrically connected by the solder portion 4A. In the connection portion 4, solder does not exist in a region (hardened portion 4 B portion) different from the solder portion 4 A collected between the first electrode 2 a and the second electrode 3 a. In a region (hardened portion 4B portion) different from the solder portion 4A, there is no solder separated from the solder portion 4A. If the amount is small, the solder may be present in a region (hardened portion 4B portion) different from the solder portion 4A collected between the first electrode 2a and the second electrode 3a.

As shown in FIG. 1A, in the connection structure 1, a plurality of solder particles gather between the first electrode 2a and the second electrode 3a, and after the plurality of solder particles are melted, the solder particles are produced. The molten metal of the above wets and spreads on the surface of the electrode and then solidifies to form a solder portion 4A. In the present embodiment, the thickness of the solder portion 4A located between the first electrode 2a and the second electrode 3a in the connection structure 1 is the average particle size of a plurality of the solder particles contained in the conductive paste. Greater than diameter. By being larger than the average particle diameter of the several said solder particle contained in the said electrically conductive paste, the connection area of the solder part 4A and the 1st electrode 2a, and the solder part 4A and the 2nd electrode 3a becomes large. By using the solder particles, the solder portion 4A and the first electrode 2a, and the solder portion 4A and the conductive portion whose conductive outer surface is a metal such as nickel, gold or copper are used. The contact area with the second electrode 3a is increased. This also increases the conduction reliability and the connection reliability in the connection structure 1. In the case where the conductive paste contains a flux, the flux is generally gradually inactivated by heating.

  When the end in the longitudinal direction of the first electrode does not reach the end of the first connection target member, the end of the first electrode in the longitudinal direction and the end of the first connection target member The distance D1 is preferably more than 0 μm, more preferably 50 μm or more, still more preferably 100 μm or more, particularly preferably 200 μm or more, preferably 1000 μm or less, more preferably 750 μm or less, still more preferably 500 μm or less. When the end in the longitudinal direction of the second electrode does not reach the end of the second connection target member, the end of the second electrode in the longitudinal direction and the end of the second connection target member The distance D2 is preferably more than 0 μm, more preferably 50 μm or more, still more preferably 100 μm or more, particularly preferably 200 μm or more, preferably 1000 μm or less, more preferably 750 μm or less, still more preferably 500 μm or less. When the distance D1 and the distance D2 satisfy the above lower limits, insulation reliability is further enhanced. A connection structure can be made small as the said distance D1 and the said distance D2 are more than the said upper limit.

  When the end in the longitudinal direction of the first electrode does not reach the end of the first connection target member, the end of the first electrode in the longitudinal direction and the end of the first connection target member The distance D1 is preferably 5 times or more, more preferably 10 times or more, still more preferably 15 times or more, preferably 100 times or less, more preferably 75 times or less, more preferably 50 times or less of the average particle size of the solder particles It is. When the end in the longitudinal direction of the second electrode does not reach the end of the second connection target member, the end of the second electrode in the longitudinal direction and the end of the second connection target member The distance D2 is preferably 5 times or more, more preferably 10 times or more, still more preferably 15 times or more, preferably 100 times or less, more preferably 75 times or less, more preferably 50 times or less of the average particle size of the solder particles It is. When the relationship between the distance D1 and the distance D2 and the average particle diameter of the solder particles satisfies the above relationship, the insulation reliability is further enhanced.

  When the longitudinal end of the first electrode does not reach the end of the first connection target member, the longitudinal end of the first electrode and the end of the first connection target member The ratio of the distance between and to the electrode width of the first electrode is preferably 0.1 or more, more preferably 0.5 or more, preferably 10 or less, more preferably 7.5 or less. When the longitudinal end of the second electrode does not reach the end of the second connection target member, the longitudinal end of the second electrode and the end of the second connection target member The ratio of the distance between them to the electrode width of the second electrode is preferably 0.1 or more, more preferably 0.5 or more, preferably 10 or less, more preferably 7.5 or less. When the above ratio satisfies the above relationship, the insulation reliability is further enhanced.

In the connection structure 1 shown in FIG. 1, all of the solder portions 4A are located in the area where the first and second electrodes 2a and 3a are facing each other. The connection structure 1X of the modified example shown in FIG. 3 differs from the connection structure 1 shown in FIG. 1 only in the connection part 4X. The connection portion 4X has a solder portion 4XA and a cured product portion 4XB. As in the connection structure 1X, most of the solder portions 4XA are located in the facing regions of the first and second electrodes 2a and 3a, and a part of the solder portions 4XA is the first and second portions. It may be protruded to the side from the field which electrode 2a, 3a has opposed. The solder portion 4XA protruding to the side from the opposing region of the first and second electrodes 2a and 3a is a part of the solder portion 4XA and is not the solder separated from the solder portion 4XA. In the present embodiment, the amount of solder separated from the solder portion can be reduced, but the solder separated from the solder portion may be present in the hardened material portion.

  The connection structure 1 can be easily obtained by reducing the amount of solder particles used. The connection structure 1X can be easily obtained by increasing the amount of solder particles used. When the amount of use of the solder particles is large, the thickness of the solder portion located between the first electrode and the second electrode in the connection structure can be determined by averaging particles of the plurality of the solder particles contained in the conductive paste. It is easy to make it larger than the diameter.

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

  First, a first connection target member 2 having a plurality of first electrodes 2a having a length direction and a width direction on the surface (upper surface) is prepared. Next, as shown in FIG. 2A, a conductive paste 11 containing a thermosetting component 11B and a plurality of solder particles 11A is disposed on the surface of the first connection target member 2 (first Process). The conductive paste 11 is disposed on the surface of the first connection target member 2 on which the first electrode 2 a is provided. After the placement of the conductive paste 11, the solder particles 11A are placed both on the first electrode 2a (line) and on the area (space) where the first electrode 2a is not formed.

  The method for arranging the conductive paste 11 is not particularly limited, but application by a dispenser, screen printing, ejection by an inkjet device, and the like can be mentioned.

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

  Next, the conductive paste 11 is heated above the melting point of the solder particles 11A and above the curing temperature of the thermosetting component 11B (third step). That is, the conductive paste 11 is heated to a temperature that is lower than the melting point of the solder particles 11A and the curing temperature of the thermosetting component 11B. At the time of this heating, the solder particles 11A present in the region where the electrode is not formed gather between the first electrode 2a and the second electrode 3a (self-aggregation effect). In this embodiment, since the end portions of the first and second electrodes 2a and 3a do not reach the end portions of the first and second connection target members 2 and 3, the solder particles 11A in the vicinity of the end portions wrap around As a result, it is difficult for the solder to be electrically connected between the electrodes adjacent in the lateral direction as a result of the solder particles appropriately flowing laterally in the vicinity of the end of the electrode than the end of the electrode. Further, in the present 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. Also, the solder particles 11A melt and bond to each other. In addition, the thermosetting component 11B is thermally cured. As a result, as shown in FIG. 2C, the connection portion 4 connecting the first connection target member 2 and the second connection target member 3 is formed of the conductive paste 11. The connection portion 4 is formed by the conductive paste 11, and the solder portion 4A is formed by joining the plurality of solder particles 11A, and the cured product portion 4B is formed by thermosetting the thermosetting component 11B. If the solder particles 11A move sufficiently, the movement of the solder particles 11A not located between the first electrode 2a and the second electrode 3a starts, and then the first electrode 2a and the second electrode It is not necessary to keep the temperature constant until the movement of the solder particles 11A is completed between 3a and 3a.

  In the case where the first and second electrodes 102a and 103a reach the end portions of the first and second connection target members 102 and 103 in both the first and second connection target members 102 and 103, respectively. It is easy to obtain the connection structure 101 as shown in FIGS. 4 (a) and 4 (b). The connection structure 101 includes a first connection target member 102, a second connection target member 103, and a connection portion 104. The first connection target member 102 has a plurality of first electrodes 102 a on the surface. The second connection target member 103 has a plurality of second electrodes 103 a on the surface. The connection portion 104 has a solder portion 104A and a cured product portion 104B. In the connection structure 101 shown in FIGS. 4A and 4B, the solder portion 104A electrically connects between the first electrodes 102a and the second electrodes 103a adjacent in the lateral direction that should not be connected. And there is a leak.

  In the present embodiment, no pressurization is performed in the second step and the third step. In the present embodiment, the weight of the second connection target member 3 is added to the conductive paste 11. Further, in the present embodiment, not the conductive film but the conductive paste is used. For this reason, at the time of formation of connection part 4, solder particles 11A gather effectively between the 1st electrode 2a and the 2nd electrode 3a. As a result, the thickness of the solder portion 4A between the first electrode 2a and the second electrode 3a tends to be large. Note that if pressing is performed in at least one of the second step and the third step, the action of collecting solder particles between the first electrode and the second electrode is inhibited. Increase the tendency to This was found by the present inventor.

  Further, in the present embodiment, since the pressurization is not performed, when the second connection target member is superimposed on the first connection target member coated with the conductive paste, the electrode of the first connection target member Even when the first connection target member and the second connection target member are overlapped in a state where the alignment of the second connection target member with the electrode is shifted, the shift is corrected and the first connection target The electrode of the member and the electrode of the second connection target member can be connected (self alignment effect). This is because the molten solder self-aggregated between the electrode of the first connection target member and the electrode of the second connection target member is between the electrode of the first connection target member and the electrode of the second connection target member. In the case where the area in which the solder and other components of the conductive paste are in contact is the smallest, energy stability is achieved, and the force of the connection structure with alignment, which is the connection structure with the smallest area, works. is there. At this time, it is desirable that the conductive paste is not cured, and that the viscosity of the components other than the solder particles of the conductive paste be sufficiently low at the temperature and time.

  The viscosity of the conductive paste at the melting point temperature of the solder is preferably 50 Pa · s or less, more preferably 10 Pa · s or less, still more preferably 1 Pa · s or less, preferably 0.1 Pa · s or more, more preferably 0.2 Pa · S or more. If it is less than a predetermined viscosity, solder particles can be efficiently aggregated, and if it is more than a predetermined viscosity, it is possible to suppress voids in the connection portion and suppress the spreading of the conductive paste to other than the connection portion. Can.

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

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

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

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

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

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

  The first and second connection target members are not particularly limited. Specifically, the first and second connection target members include semiconductor chips, semiconductor packages, LED chips, LED packages, electronic components such as capacitors and diodes, resin films, printed boards, flexible printed boards, flexible Examples include electronic components such as flat cables, rigid flexible substrates, glass epoxy substrates, and circuit substrates such as glass substrates. The first and second connection target members are preferably electronic components.

  It is preferable that at least one of the first connection target member and the second connection target member is a resin film, a flexible printed board, a flexible flat cable, or a rigid flexible board. It is preferable that the said 2nd connection object member is a resin film, a flexible printed circuit board, a flexible flat cable, or a rigid flexible substrate. The resin film, the flexible printed circuit, the flexible flat cable and the rigid flexible substrate have properties of high flexibility and relatively light weight. When a conductive film is used to connect such a connection target member, the solder particles tend to be difficult to collect on the electrode. On the other hand, even if a resin film, a flexible printed circuit, a flexible flat cable, or a rigid flexible substrate is used, the conduction reliability between the electrodes can be sufficiently improved by efficiently collecting the solder particles on the electrodes. it can. When using a resin film, a flexible printed board, a flexible flat cable, or a rigid flexible board, compared with the case where other connection target members such as a semiconductor chip are used, reliability of conduction between electrodes by not applying pressure The improvement effect can be obtained more effectively.

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

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

  The viscosity can be appropriately adjusted to the type and the amount of the blended components. Also, the use of a filler can make the viscosity relatively high.

  The viscosity can be measured under conditions of 25 ° C. and 5 rpm using, for example, an E-type viscometer (manufactured by Toki Sangyo Co., Ltd.) or the like.

  In the plurality of solder portions, the electrode width of the first electrode and the electrode width of the second electrode are preferably 50 μm or more, more preferably 75 μm or more, preferably 1000 μm from the viewpoint of enhancing the uniformity of the amount of solder. Or less, more preferably 500 μm or less, still more preferably 250 μm or less. The electrode width is the width of the line (L) in L / S. The inter-electrode width of the first electrode and the inter-electrode width of the second electrode are preferably 50 μm or more, more preferably 75 μm or more, and preferably 1000 μm from the viewpoint of further enhancing conduction reliability and insulation reliability. Or less, more preferably 500 μm or less, still more preferably 250 μm or less. The inter-electrode width is the width of the space (S) in L / S. The effect of the present invention is more effectively exhibited as the electrode width and the inter-electrode width decrease in the order of 100 μm or less, 85 μm or less, and 70 μm or less.

  The conductive paste contains a thermosetting component and a plurality of solder particles. It is preferable that the said thermosetting component contains the curable compound (thermosetting compound) which can be hardened | cured by heating, and a thermosetting agent. From the viewpoint of effectively removing the oxide film on the surface of the solder particle and the surface of the electrode and further reducing the connection resistance, the conductive paste preferably contains a flux.

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

(Solder particles)
The solder particles have solder on the conductive outer surface. In the solder particles, both the central portion and the conductive outer surface are formed by solder. The solder particles are particles in which both the central portion and the conductive outer surface are solder.

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

  The zeta potential is measured as follows.

How to measure zeta potential:
0.05 g of solder particles are placed in 10 g of methanol and subjected to ultrasonication or the like to be dispersed uniformly to obtain a dispersion. The zeta potential can be measured by an electrophoresis measurement method using this dispersion and using "Delsamax PRO" manufactured by Beckman Coulter.

  The zeta potential of the solder particles is preferably 0 mV or more, more preferably more than 0 mV, preferably 10 mV or less, more preferably 5 mV or less, still more preferably 1 mV or less, still more preferably 0.7 mV or less, particularly preferably 0.5 mV It is below. When the zeta potential is less than or equal to the above upper limit, the solder particles are less likely to aggregate in the conductive paste before use. When the zeta potential is 0 mV or more, solder particles are efficiently aggregated on the electrode at the time of mounting.

  The solder particles preferably have a solder particle body and an anionic polymer disposed on the surface of the solder particle body, because it is easy to make the zeta potential of the surface positive. It is preferable that the said solder particle is obtained by surface-treating a solder particle main body with the compound used as anionic polymer or an anionic polymer. It is preferable that the said solder particle is a surface treatment by the compound used as an anion polymer or an anion polymer. The anionic polymer and the compound to be the anionic polymer may be used alone or in combination of two or more.

  As a method of surface-treating the solder particle body with an anionic polymer, for example, a (meth) acrylic polymer copolymerized with (meth) acrylic acid, a dicarboxylic acid and a diol as an anionic polymer, and having carboxyl groups at both ends Polyester polymer, polymer obtained by intermolecular dehydration condensation reaction of dicarboxylic acid and having carboxyl group at both ends, polyester polymer synthesized from dicarboxylic acid and diamine and having carboxyl group at both ends, and modified POVAL (having carboxyl group) The method of making the carboxyl group of an anion polymer and the hydroxyl group of the surface of a solder particle main body react using Nippon Synthetic Chemical Co., Ltd. "Gosenex T") etc. is mentioned.

Examples of the anionic portion of the anionic polymer, the carboxyl group and the like, in otherwise, tosyl group _{(p-H 3 CC 6 H} 4 S (= O) 2 -), sulfonate ion group (-SO ₃ ^- And phosphate ion groups (—PO ₄ ⁻ ) and the like.

  Another method is to use a compound having a functional group that reacts with a hydroxyl group on the surface of the solder particle body, and further having a functional group that can be polymerized by addition or condensation reaction. Methods of polymerizing on the surface can be mentioned. As a functional group which reacts with a hydroxyl group on the surface of the solder particle main body, a carboxyl group, an isocyanate group, etc. are mentioned, As a functional group polymerized by addition and condensation reaction, a hydroxyl group, a carboxyl group, an amino group, and An acryloyl group is mentioned.

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

  It is easy to arrange an anionic polymer on the surface of the solder particle body as the above-mentioned weight average molecular weight is more than the above-mentioned lower limit and below the above-mentioned upper limit, and it is easy to make zeta potential of the surface of solder particle positive. The solder particles can be arranged more efficiently on the electrode.

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

  The weight average molecular weight of the polymer obtained by surface treatment of the solder particle main body with a compound to be an anionic polymer dissolves the solder in the solder particles and removes the solder particles by dilute hydrochloric acid or the like which does not cause decomposition of the polymer. And the weight average molecular weight of the remaining polymer can be determined.

It is preferable that the said solder is a metal (low melting metal) whose melting | fusing point is 450 degrees C or less. It is preferable that the said solder particle is a metal particle (low melting-point metal particle) whose melting | fusing point is 450 degrees C or less. The low melting point metal particles are particles containing a low melting point metal. The low melting point metal means a metal having a melting point of 450 ° C. or less. The melting point of the low melting point metal is preferably 300 ° C. or less, more preferably 160 ° C. or less. Also, the solder particles contain tin. The content of tin is preferably 30% by weight or more, more preferably 40% by weight or more, still more preferably 70% by weight or more, particularly preferably 90% by weight or more, in 100% by weight of the metal contained in the solder particles. The connection reliability of a solder part and an electrode becomes it still higher that content of the tin in the said solder particle | grain is more than the said minimum.

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

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

  The low melting point metal which comprises the said solder particle is not specifically limited. The low melting point metal is preferably tin or an alloy containing tin. Examples of the alloy include tin-silver alloy, tin-copper alloy, tin-silver-copper alloy, tin-bismuth alloy, tin-zinc alloy, tin-indium alloy and the like. 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, or a tin-indium alloy because the wettability to the electrode is excellent. More preferably, tin-bismuth alloy or tin-indium alloy is used.

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

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

  The average particle size of the solder particles is preferably 0.5 μm or more, more preferably 1 μm or more, still more preferably 3 μm or more, particularly preferably 5 μm or more, preferably 100 μm or less, more preferably less than 80 μm, still more preferably 75 μm The following is more preferably 60 μm or less, still more preferably 40 μm or less, still more preferably 30 μm or less, still more preferably 20 μm or less, particularly preferably 15 μm or less, most preferably 10 μm or less. Solder particles can be arranged more efficiently on the electrode as the average particle diameter of the solder particles is not less than the lower limit and not more than the upper limit. The average particle diameter of the solder particles is particularly preferably 3 μm or more and 30 μm or less.

  The “average particle size” of the solder particles indicates a number average particle size. The average particle size of the solder particles can be determined, for example, by observing 50 arbitrary solder particles with an electron microscope or an optical microscope and calculating an average value.

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

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

CV value (%) = (ρ / Dn) × 100
ρ: Standard deviation of particle diameter of solder particle Dn: Average value of particle diameter of solder particle

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

  The content of the solder particles is preferably 1% by weight or more, more preferably 2% by weight or more, still more preferably 10% by weight or more, particularly preferably 20% by weight or more, and most preferably 30% by weight in 100% by weight of the conductive paste. The content is preferably at least 80% by weight, more preferably at most 60% by weight, still more preferably at most 50% by weight. When the content of the solder particles 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, and it is easy to arrange many solder particles between the electrodes, The conduction reliability is further enhanced. From the viewpoint of further enhancing the conduction reliability, it is preferable that the content of the solder particles is large.

  In particular, the content of the solder particles is preferably 1% by weight or more and preferably 80% by weight or less in 100% by weight of the conductive paste. In this case, the solder particles are efficiently collected on the electrode, and the conduction reliability is further enhanced.

(Compounds curable by heating: 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, epoxy compounds are preferable from the viewpoint of further improving the curability and viscosity of the conductive paste and further enhancing the connection reliability.

  As said epoxy compound, an aromatic epoxy compound is mentioned. Among them, crystalline epoxy compounds such as resorcinol type epoxy compounds, naphthalene type epoxy compounds, biphenyl type epoxy compounds and benzophenone type epoxy compounds are preferable. The epoxy compound which is solid at normal temperature (23 ° C.) and whose melting temperature is equal to or lower than the melting point of the solder is preferable. The melting temperature is preferably 100 ° C. or less, more preferably 80 ° C. or less, preferably 40 ° C. or more. By using the above-described preferable epoxy compound, when the connection target member is bonded, the viscosity is high, and when an impact such as transport is given an acceleration, the second connection is made with the first connection target member. Positional displacement with the target member can be suppressed, and the viscosity of the conductive paste can be greatly reduced by heat at the time of curing, and aggregation of the solder particles can be efficiently advanced.

The content of the thermosetting compound is preferably 20% by weight or more, more preferably 40% by weight or more, still more preferably 50% by weight or more, preferably 99% by weight or less, based on 100% by weight of the conductive paste. Is preferably at most 98 wt%, more preferably at most 90 wt%, particularly preferably at most 80 wt%. From the viewpoint of further improving the impact resistance, it is preferable that the content of the thermosetting component is large.

(Thermosetting agent: thermosetting component)
The thermosetting agent thermally cures the thermosetting compound. Examples of the thermosetting agent include imidazole curing agents, amine curing agents, phenol curing agents, thiol curing agents such as polythiol curing agents, acid anhydrides, thermal cation initiators (thermal cationic curing agents), thermal radical generating agents, etc. Be Only one type of the thermosetting agent may be used, or two or more types may be used in combination.

  Among these, an imidazole curing agent, a thiol curing agent or an amine curing agent is preferable because the conductive paste can be cured more rapidly at a low temperature. Moreover, since a storage stability becomes high when the curable compound which can be hardened | cured by heating and the said thermosetting agent are mixed, a latent hardening agent is preferable. The latent curing agent is preferably a latent imidazole curing agent, a latent thiol curing agent or a latent amine curing agent. The thermosetting agent may be coated with a polymeric substance such as a polyurethane resin or a polyester resin.

  The imidazole curing agent is not particularly limited, and 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- The triazine isocyanuric acid adduct etc. are mentioned.

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

  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, metaphenylene diamine, diaminodiphenyl sulfone and the like can be mentioned.

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

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

The reaction initiation temperature of the heat curing agent is preferably 50 ° C. or more, more preferably 70 ° C. or more, still more preferably 80 ° C. or more, preferably 250 ° C. or less, more preferably 200 ° C. or less, still more preferably 150 ° C. or less Particularly preferably, it is 140 ° C. or less. When 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 disposed on the electrode. The reaction initiation temperature of the thermosetting agent is particularly preferably 80 ° C. or more and 140 ° C. or less.

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

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

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

(flux)
The conductive paste preferably contains a flux. The use of flux allows the solder to be placed more effectively on the electrodes. The flux is not particularly limited. As the flux, a flux generally used for solder bonding can be used. Examples of the flux include zinc chloride, a mixture of zinc chloride and an inorganic halide, a mixture of zinc chloride and an inorganic acid, a molten salt, phosphoric acid, a derivative of phosphoric acid, an organic halide, hydrazine, an organic acid and rosin. Etc. Only one type of flux may be used, or two or more types may be used in combination.

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

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

  The activation temperature (melting point) of the flux is preferably 50 ° C. or more, more preferably 70 ° C. or more, still more preferably 80 ° C. or more, preferably 200 ° C. or less, more preferably 190 ° C. or less, still more preferably 160 ° C. or less More preferably, it is 150 ° C. or less, still more preferably 140 ° C. or less. The flux effect is exhibited more effectively as the activation temperature of the above-mentioned flux is more than the above-mentioned lower limit and below the above-mentioned upper limit, and solder particles are arranged more efficiently on an electrode. The activation temperature of the flux is preferably 80 ° C. or more and 190 ° C. or less. The activation temperature of the flux is particularly preferably 80 ° C. or more and 140 ° C. or less.

As the flux having a melting point of 80 ° C. to 190 ° C., succinic acid (melting point 186 ° C.), glutaric acid (melting point 96 ° C.), adipic acid (melting point 152 ° C.), pimelic acid (melting point 104 ° C.), suberic acid Dicarboxylic acids such as (melting point 142 ° C.), benzoic acid (melting point 122 ° C.),
Malic acid (melting point 130 ° C.) and the like can be mentioned.

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

  From the viewpoint of arranging the solder more efficiently on the electrodes, the melting point of the flux is preferably higher than the melting point of the solder in the solder particles, more preferably 5 ° C. or more, and preferably 10 ° C. or more. Is more preferred.

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

  The flux may be dispersed in the conductive paste or may be deposited on the surface of the solder particles.

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

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

  Examples of the flux which releases a cation by the heating include the above-mentioned thermal cation initiator.

  The content of the flux is preferably 0.5% by weight or more, preferably 30% by weight or less, and more preferably 25% by weight or less, based on 100% by weight of the conductive paste. The conductive paste may not contain flux. When the content of the flux is at least the above lower limit and the above upper limit, it is more difficult to 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 is more effective Can be removed.

(Other ingredients)
The conductive paste may optionally contain, for example, a filler, an extender, a softener, a plasticizer, a polymerization catalyst, a curing catalyst, a colorant, an antioxidant, a heat stabilizer, a light stabilizer, a UV absorber, and a lubricant. And various additives such as an antistatic agent and a flame retardant may be included.

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

Polymer A:
Synthesis of Reactant (Polymer A) of Bisphenol F with 1,6-Hexanediol Diglycidyl Ether, and Bisphenol F Type Epoxy Resin:
100 parts by weight of bisphenol F (containing 2,4: 1 by weight ratio of 4,4'-methylene bisphenol, 2,4'-methylene bisphenol and 2,2'-methylene bisphenol), 1,6-hexanediol di 130 parts by weight of glycidyl ether, 5 parts by weight of bisphenol F type epoxy resin (“EPICLON EXA-830 CRP” manufactured by DIC), and 10 parts by weight of resorcinol type epoxy compound (“EX-201” manufactured by Nagase ChemteX Corporation) It was placed in a mouth flask and dissolved at 100 ° C. under nitrogen flow. Thereafter, 0.15 parts by weight of triphenylbutylphosphonium bromide, which is a catalyst for addition reaction of hydroxyl group and epoxy group, is added, and the reaction product (polymer A) is caused to undergo addition polymerization reaction at 140 ° C. for 4 hours under nitrogen flow. Got).

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

  The weight average molecular weight of the reaction product (polymer A) obtained by GPC was 28,000, and the number average molecular weight was 8,000.

  Polymer B: Both-end epoxy group rigid-skeleton phenoxy resin, manufactured by Mitsubishi Chemical Corporation "YX6900BH45", weight average molecular weight 16000

  Thermosetting compound 1: resorcinol type epoxy compound, manufactured by Nagase ChemteX "EX-201"

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

  Thermosetting agent 1: trimethylolpropane tris (3-mercaptopropionate), "TMMP" manufactured by SC Organic Chemical Company

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

  Flux 1: Adipic acid, manufactured by Wako Pure Chemical Industries, Ltd., melting point (activation temperature) 152 ° C.

Method of producing solder particles 1 to 3:
Solder particles having anion polymer 1: 200 g of solder particle body, 40 g of adipic acid and 70 g of acetone are weighed in a three-necked flask, and then dehydration condensation of hydroxyl group on the surface of the solder particle body and carboxyl group of adipic acid 0.3 g of dibutyltin oxide as a catalyst was added and reacted at 60 ° C. for 4 hours. Thereafter, the solder particles were collected by filtration.

  The collected solder particles, 50 g of adipic acid, 200 g of toluene, and 0.3 g of p-toluenesulfonic acid were weighed in a three-necked flask, and reacted at 120 ° C. for 3 hours while performing vacuum suction and reflux. . Under the present circumstances, it was made to react, removing the water produced | generated by dehydration condensation using a Dean-Stark extraction apparatus.

  Thereafter, the solder particles were recovered by filtration, washed with hexane and dried. Thereafter, the obtained solder particles are crushed by a ball mill, and a sieve is selected so as to obtain a predetermined CV value.

(Zeta potential measurement)
In addition, 0.05 g of solder particles having the anionic polymer 1 was obtained using the obtained solder particles,
It was put into 10 g of methanol, and was uniformly dispersed by ultrasonication to obtain a dispersion. The zeta potential was measured by an electrophoresis measurement method using this dispersion and using "Delsamax PRO" manufactured by Beckman Coulter.

(Weight-average molecular weight of anionic polymer)
The weight average molecular weight of the anionic polymer 1 on the surface of the solder particle was determined by GPC after the solder was dissolved using 0.1 N hydrochloric acid, and the polymer was recovered by filtration.

(CV value of solder particle)
The CV value was measured with a laser diffraction type particle size distribution measuring apparatus ("LA-920" manufactured by Horiba, Ltd.).

  Solder particles 1 (SnBi solder particles, melting point 139 ° C., solder particle main body selected from Mitsui Metals Corporation “ST-3”, solder particles having anionic polymer 1 subjected to surface treatment, average particle diameter 4 μm, CV value 7%, zeta potential of surface: +0.65 mV, polymer molecular weight Mw = 6500)

  Solder particles 2 (SnBi solder particles, melting point 139 ° C., “DS10” manufactured by Mitsui Metals, Inc., using solder particle main body, solder particles having anionic polymer 1 subjected to surface treatment, average particle diameter 13 μm, CV value 20% Surface zeta potential: +0.48 mV, polymer molecular weight Mw = 7000)

  Solder particles 3 (SnBi solder particles, melting point 139 ° C., “10-25” manufactured by Mitsui Metals, Inc., using solder particle main body, solder particles having anionic polymer 1 subjected to surface treatment, average particle diameter 25 μm, CV value 15%, zeta potential of surface: +0.4 mV, polymer molecular weight Mw = 8000)

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

Method of producing conductive particle 1:
Electroless nickel plating was performed on divinyl benzene resin particles ("Micropearl SP-210" manufactured by Sekisui Chemical Co., Ltd.) having an average particle diameter of 10 μm to form a base nickel plating layer with a thickness of 0.1 μm on the surface of the resin particles. Subsequently, the resin particle in which the base nickel plating layer was formed was electrolytically copper-plated, and the 1-micrometer-thick copper layer was formed. Furthermore, it electroplated using the electroplating solution containing tin and bismuth, and formed the 3 micrometers-thick solder layer. Thus, a 1 μm thick copper layer is formed on the surface of the resin particle, and a 3 μm thick solder layer (tin: bismuth = 43% by weight: 57% by weight) is formed on the surface of the copper layer Conductive particles 1 were produced.

  Phenoxy resin ("NY-50S" manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.)

(Examples 1 to 5 and 11 and Comparative Example 3)
(1) Preparation of anisotropic conductive paste The components shown in Table 1 below were blended in the amounts shown in Table 1 below to obtain an anisotropic conductive paste.

(2) Preparation of first connection structure (L / S = 50 μm / 50 μm) It has a copper electrode pattern (copper electrode thickness 12 μm) of 50 μm / 50 μm and electrode length 3 mm at L / S on the top surface The longitudinal end of the copper electrode is 200 from the end of the glass epoxy substrate
A glass epoxy substrate (FR-4 substrate) (first connection target member) separated by 1 μm was prepared.

  Also, it has a copper electrode pattern (copper electrode thickness 12 μm) with L / S of 50 μm / 50 μm and electrode length of 3 mm on the lower surface, and the end of copper electrode in the lengthwise direction is 200 μm from the end of flexible printed circuit board A flexible printed circuit board (second connection target member) separated was prepared.

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

  At the top of the glass epoxy substrate, with an air dispenser, the central portion in the electrode length direction so that the thickness of the anisotropic conductive paste immediately after preparation is 150 μm and the width is 0.8 mm on the electrode of the glass epoxy substrate. To form an anisotropic conductive paste layer. Next, the said flexible printed circuit board was laminated | stacked so that electrodes might oppose on the upper surface of an anisotropic conductive paste layer. At this time, no pressure was applied. The weight of the flexible printed board is added to the anisotropic conductive paste layer. Thereafter, the solder is melted while heating from the glass epoxy substrate side on the hot plate so that the temperature of the anisotropic conductive paste layer becomes 190 ° C., and the anisotropic conductive paste layer is cured at 190 ° C. and 10 seconds To obtain a first connection structure.

(3) Preparation of second connection structure (L / S = 75 μm / 75 μm) L / S has a copper electrode pattern (copper electrode thickness 12 μm) of 75 μm / 75 μm, electrode length 3 mm, and A glass epoxy substrate (FR-4 substrate) (first connection target member) was prepared in which the end in the lengthwise direction of the copper electrode was separated by 200 μm from the end of the glass epoxy substrate.

  In addition, L / S has a copper electrode pattern (copper electrode thickness 12 μm) of 75 μm / 75 μm and electrode length of 3 mm on the lower surface, and the end in the length direction of copper electrode is 200 μm from the end of glass epoxy A flexible printed circuit board (second connection target member) separated was prepared.

  A second connection structure was obtained in the same manner as the preparation of the first connection structure except that the above-described glass epoxy substrate and flexible printed substrate different in L / S were used.

(4) Preparation of third connection structure (L / S = 100 μm / 100 μm) It has a copper electrode pattern (copper electrode thickness 12 μm) with L / S 100 μm / 100 μm, electrode length 3 mm on the top surface, and A glass epoxy substrate (FR-4 substrate) (first connection target member) was prepared in which the end in the lengthwise direction of the copper electrode was separated by 200 μm from the end of the glass epoxy substrate. In this glass epoxy substrate, the solder resist film is in the form of a pattern as a whole, and the electrode and the solder resist film are connected.

  In addition, L / S has a copper electrode pattern (copper electrode thickness 12 μm) of 100 μm / 100 μm and electrode length of 3 mm on the lower surface, and the end in the lengthwise direction of the copper electrode is 200 μm from the end of the glass epoxy substrate A flexible printed circuit board (second connection target member) separated was prepared.

  A third connection structure was obtained in the same manner as the preparation of the first connection structure except that the above-described glass epoxy substrate and flexible printed substrate different in L / S were used.

(Example 6)
In the first, second, and third connection target members used for the first, second, and third connection structures, an end portion in the lengthwise direction of the copper electrode is separated by 100 μm from each of the end portions of the glass epoxy substrate and the flexible printed substrate First, second and third connection structures were obtained in the same manner as in Example 1 except for the above.

(Example 7)
In the first, second, and third connection target members used for the first, second, and third connection structures, the end portions in the lengthwise direction of the copper electrode are separated by 300 μm from the end portions of the glass epoxy substrate and the flexible printed circuit board, respectively. First, second and third connection structures were obtained in the same manner as in Example 1 except for the above.

(Example 8)
In the first, second, and third connection target members used for the first, second, and third connection structures, an end portion in the lengthwise direction of the copper electrode is separated by 500 μm from each of the end portions of the glass epoxy substrate and the flexible printed substrate First, second and third connection structures were obtained in the same manner as in Example 1 except for the above.

(Example 9)
The second connection target member used for the first, second, and third connection structures is the same as Example 1 except that the end in the lengthwise direction of the copper electrode is aligned with the end of the glass epoxy substrate. The first, second and third connection structures were obtained. In Example 9, in the first connection target member used for the first, second, and third connection structures, the end in the lengthwise direction of the copper electrode is not aligned with the end of the flexible printed circuit.

(Example 10)
First, second and third connection structures were obtained in the same manner as in Example 1 except that a pressure of 1 MPa was applied during heating of the first conductive paste layer.

(Example 12)
In the first, second, and third connection target members used for the first, second, and third connection structures, an end portion in the lengthwise direction of the copper electrode is separated by 10 μm from each of the end portions of the glass epoxy substrate and the flexible printed substrate First, second and third connection structures were obtained in the same manner as in Example 1 except for the above.

(Example 13)
In the first, second, and third connection target members used for the first, second, and third connection structures, an end portion in the lengthwise direction of the copper electrode is separated by 50 μm from each of the end portions of the glass epoxy substrate and the flexible printed substrate First, second and third connection structures were obtained in the same manner as in Example 1 except for the above.

(Example 14)
In the first, second, and third connection target members used for the first, second, and third connection structures, an end portion in the lengthwise direction of the copper electrode is separated by 100 μm from each of the end portions of the glass epoxy substrate and the flexible printed substrate First, second and third connection structures were obtained in the same manner as in Example 3 except for the above.

(Comparative example 1)
In the first, second, and third connection target members used in the first, second, and third connection structures, the longitudinal ends of the copper electrode are aligned with the ends of the glass epoxy substrate and the flexible printed board, respectively. First, second and third connection structures were obtained in the same manner as Example 1 except for the above.

(Comparative example 2)
A solution was obtained by dissolving 12 parts by weight of a phenoxy resin ("YP-50S" manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.) in methyl ethyl ketone (MEK) such that the solid content was 50% by weight. The components except for the phenoxy resin shown in Table 1 below are blended with the compounding amounts shown in Table 1 below and the total amount of the above-mentioned solution, and stirred for 5 minutes at 2000 rpm using a planetary stirrer, and then the bar coater It coated on release PET (polyethylene terephthalate) film so that the thickness after drying using it might be 30 micrometers. The anisotropic conductive film was obtained by removing MEK by vacuum-drying at room temperature.

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

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

(2) Thickness of Solder Portion The thickness of the solder portion located between the upper and lower electrodes was evaluated by observing the cross section of the obtained connection structure.

(3) Placement accuracy of the solder on the electrode In the cross section of the obtained first, second and third connection structures (cross section in the direction shown in FIG. 1A), the electrode in 100% of the total area of the solder The area (%) of the solder remaining in the cured product apart from the solder portion disposed between was evaluated. In addition, the average of the area in five cross sections was calculated. The placement accuracy of the solder on the electrode was determined according to the following criteria.

[Criteria for determining placement accuracy of conductive particles on electrodes]
○: The area of the solder (solder particles) remaining in the cured product apart from the solder portion disposed between the electrodes is 0% or more and 1% or less of the total area 100% of the solder appearing in the cross section :: The area of the solder (solder particles) remaining in the hardened material apart from the solder portion disposed between the electrodes is 100% or less and 10% or less of the total area 100% of the solder appearing in the cross section :: The area of the solder (solder particles) remaining in the cured product apart from the solder portion disposed between the electrodes is 10% or more and 30% or less of the total area of 100% of the solder appearing in the cross section X: The area of the solder (solder particles) remaining in the cured product apart from the solder part disposed between the electrodes is over 30% in 100% of the total area of the solder appearing in the cross section

(4) Conduction reliability between upper and lower electrodes In the obtained first, second and third connection structures (n = 15), the connection resistance per one connection point between the upper and lower electrodes is 4 It measured by the terminal method. The average value of connection resistance was calculated. The connection resistance can be determined from the relationship of voltage = current × resistance by measuring the voltage when a constant current flows. The conduction reliability was determined based on the following criteria.

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

(5) Insulating reliability between adjacent electrodes In the obtained first, second and third connection structures (n = 15), after being left in an atmosphere of 85 ° C. and humidity 85% for 100 hours, they are adjacent 5 V was applied between the electrodes to be measured, and the resistance value was measured at 25 points. The insulation reliability was judged according to the following criteria.

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

  The results are shown in Table 1 below.

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

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

Claims (12)

A conductive paste containing a thermosetting component and a plurality of solder particles, a first connection target member having a plurality of first electrodes having a length direction and a width direction on the surface, and a length direction and a width direction Using a second connection target member having a plurality of second electrodes on the surface,
Placing the conductive paste on the surface of the first connection target member;
And disposing the second connection target member such that the first electrode and the second electrode face each other on the surface of the conductive paste opposite to the first connection target member. ,
A connection portion connecting the first connection target member and the second connection target member by heating the conductive paste to a temperature equal to or higher than the melting point of the solder particles and equal to or higher than a curing temperature of the thermosetting component. And a step of forming the conductive paste and electrically connecting the first electrode and the second electrode by a solder portion in the connection portion.
As the first connection target member, the end in the lengthwise direction of the first electrode does not reach the end of the first connection target member in a portion opposed to the second connection target member The first connection target member is used, or, as the second connection target member, the second end of the second electrode in the length direction is the second portion of the portion facing the first connection target member The manufacturing method of a connection structure using the 2nd connection object member which has not reached the end part of a connection object member.   The distance between the end in the longitudinal direction of the first electrode and the end of the first connection target member is larger than the electrode width of the first electrode, or the length of the second electrode The method for manufacturing a connection structure according to claim 1, wherein a distance between an end of the direction and an end of the second connection target member is larger than an electrode width of the second electrode. Whether the ratio of the distance between the end of the first electrode in the longitudinal direction and the end of the first connection target member to the electrode width of the first electrode is 0.1 or more and 10 or less Or, the ratio of the distance between the end in the longitudinal direction of the second electrode and the end of the second connection target member to the electrode width of the second electrode is 0.1 or more and 10 or less The manufacturing method of the connection structure of Claim 1 which is. The distance between the end in the longitudinal direction of the first electrode and the end of the first connection target member is 50 μm or more and 1000 μm or less, or the end in the longitudinal direction of the second electrode The manufacturing method of the connection structure according to any one of claims 1 to 3 , wherein a distance between the second connection target member and the end of the second connection target member is 50 μm or more and 1000 μm or less. The distance between the end in the longitudinal direction of the first electrode and the end of the first connection target member is not less than 5 times and not more than 100 times the average particle diameter of the solder particles, or the distance between the longitudinal end of the second electrode and the end of the second connection object member, either the solder particles having an average particle size of 5 times or more of, is 100 times or less, of claims 1-4 The manufacturing method of the connection structure of any one of-.   As the first connection target member, the end in the lengthwise direction of the first electrode does not reach the end of the first connection target member in a portion opposed to the second connection target member The second connection target member is used as the second connection target member, and the second end of the second electrode in the lengthwise direction is opposed to the first connection target member. The manufacturing method of the connection structure of any one of Claims 1-5 using the 2nd connection object member which has not reached the end part of a connection object member. In the step of arranging the second connection target member and the step of forming the connection portion, no pressure is applied, and the weight of the second connection target member is added to the conductive paste, or
In at least one of the step of arranging the second connection target member and the step of forming the connection portion, pressing is performed, and the step of arranging the second connection target member and the connection portion is formed. The manufacturing method of the connection structure of any one of Claims 1-6 whose pressure of pressurization is less than 1 MPa in both of the process.   8. The method according to claim 7, wherein in the step of arranging the second connection target member and the step of forming the connection portion, no weight is applied and the weight of the second connection target member is added to the conductive paste. Manufacturing method of connection structure.   The manufacturing method of the connection structure according to any one of claims 1 to 8, wherein an average particle diameter of the solder particles is 0.5 μm or more and 100 μm or less.   The manufacturing method of the connection structure of any one of Claims 1-9 whose content of the said solder particle in the said electrically conductive paste is 10 weight% or more and 80 weight% or less.   The manufacturing method of the connection structure of any one of Claims 1-10 whose said 2nd connection object member is a resin film, a flexible printed circuit board, a rigid flexible substrate, or a flexible flat cable. The electrode width of the first electrode is 50 μm or more and 1000 μm or less,
The electrode width of the second electrode is 50 μm or more and 1000 μm or less,
The inter-electrode width of the first electrode is 50 μm or more and 1000 μm or less,
The manufacturing method of the connection structure according to any one of claims 1 to 11, wherein an inter-electrode width of the second electrode is 50 μm or more and 1000 μm or less.

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