JP6514610B2 - 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.

  Further, as a new problem not described in Patent Document 1, three or more connection target members are connected using a conductive paste containing solder particles, and electrodes on both surfaces of the connection target member positioned in the middle are When electrically connecting the electrode on the upper surface of the lower connection target member to the electrode on the lower surface of the upper connection target member, solder powder may not be efficiently collected between the electrodes. It was found by the present inventor.

  An object of the present invention is to provide a method of manufacturing a connection structure in which solder particles can be efficiently disposed between electrodes and the reliability of conduction between the electrodes can be enhanced.

  According to a broad aspect of the present invention, there is provided a first connection target member having at least one first electrode on the top surface, using a second conductive paste containing a thermosetting component and a plurality of solder particles. A second connection target member having one second electrode on the upper surface and at least one second electrode on the lower surface is connected by a first connection portion including conductive particles, and the upper surface Using a laminate in which the first electrode and the second electrode on the lower surface are electrically connected by a first conductive portion derived from the conductive particle, and at least one third electrode Placing a second conductive paste layer on the top surface of the second connection target member in the laminate using the third connection target member having the lower surface on the lower surface And on the top surface of the second conductive paste layer Arranging the third connection target member so that the second electrode on the upper surface faces the third electrode on the lower surface from the lower surface side, and the solder included in the second conductive paste layer The second connection target member and the third connection target member are connected by heating the second conductive paste layer to a temperature equal to or higher than the melting point of the particles and to a temperature equal to or higher than the curing temperature of the thermosetting component. The second connection portion is formed of the second conductive paste layer, and the second electrode on the upper surface and the third electrode on the lower surface are connected to a second solder portion in the second connection portion. Electrically connecting according to the second connection target member, the second electrode does not face each other on the upper surface and the lower surface of the second connection target member; The second electrode is misaligned on the upper surface and the lower surface of the target member Using the connection object member, the manufacturing method of the connecting structure is provided.

  According to a broad aspect of the present invention, using a first conductive paste containing a thermosetting component and a plurality of solder particles, using a second conductive paste containing a thermosetting component and a plurality of solder particles A second connection having at least one second electrode on the upper surface and at least one second electrode on the lower surface, using a first connection target member having at least one first electrode on the upper surface The first conductive paste is applied on the upper surface of the first connection target member using the target member and using the third connection target member having at least one third electrode on the lower surface. A step of arranging a first conductive paste layer, and on the upper surface of the first conductive paste layer, the second connection target member from the lower surface side, the first electrode of the upper surface and the Arranging the two electrodes so as to face each other, By heating the first conductive paste layer to a temperature equal to or higher than the melting point of the solder particles contained in the first conductive paste layer and equal to or higher than the curing temperature of the thermosetting component, the first connection target member and the second connection target member A first connection portion connecting the connection target member to the connection target member is formed of the first conductive paste layer, and the first electrode on the upper surface and the second electrode on the lower surface are A step of electrically connecting by the first solder portion in the first connection portion, and arranging a second conductive paste layer on the upper surface of the second connection target member using the second conductive paste And the third connection target member is disposed on the upper surface of the second conductive paste layer so that the second electrode on the upper surface faces the third electrode on the lower surface from the lower surface side. And the solder particles contained in the second conductive paste layer A second connection target member and the third connection target member by heating the second conductive paste layer to a temperature higher than the melting point of the second conductive paste layer and higher than a curing temperature of the thermosetting component. The connection portion is formed of the second conductive paste layer, and the second electrode on the upper surface and the third electrode on the lower surface are formed by the second solder portion in the second connection portion. And electrically connecting the second electrode as the second connection target member on the upper surface and the lower surface of the second connection target member, and the second electrode is not opposed to the second connection target member. A method of manufacturing a connection structure is provided, using a second connection target member in which the positions of the second electrodes are shifted on the upper surface and the lower surface of the member.

  In a specific aspect of the method for manufacturing a connection structure according to the present invention, when the second connection portion is formed by the second conductive paste layer, the heating of the second conductive paste layer is started from the start of heating. The time to reach the melting point of the solder particles contained in the second conductive paste layer is 2 seconds or more and 60 seconds or less.

  In a specific aspect of the method of manufacturing a connection structure according to the present invention, no pressure is applied in the step of arranging the third connection target member and the step of forming the third connection portion. Weight of the third connection target member is added to the conductive paste layer, or at least one of the step of arranging the third connection target member and the step of forming the third connection portion In both of the step of applying pressure and disposing the third connection target member and the step of forming the third connection portion, the pressure of the pressure is less than 1 MPa.

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

  In a specific aspect of the method of manufacturing a connection structure according to the present invention, when the first connection portion is formed of the first conductive paste layer, the heating is started from the start of heating the first conductive paste layer. The time to reach the melting point of the solder particles contained in the first conductive paste layer is 2 seconds or more and 60 seconds or less, and the second connection portion is formed by the second conductive paste layer The time from the start of heating of the second conductive paste layer to reaching the melting point of the solder particles contained in the second conductive paste layer is set to 2 seconds or more and 60 seconds or less.

  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 second connection portion, no pressurization is performed, and the first Weight of the second connection target member is added to the conductive paste layer, or at least one of the step of arranging the second connection target member and the step of forming the second connection portion The pressing pressure is less than 1 MPa in both of the step of pressing and disposing the second connection target member and the step of forming the second connection portion, and the third connection target In the step of arranging the member and the step of forming the third connection portion, no pressure is applied, and the weight of the third connection target member is added to the second conductive paste layer, or Step of arranging the third connection target member And in at least one of the steps of forming the third connection portion, in both of the step of applying pressure and arranging the third connection target member and the step of forming the third connection portion. And the pressure of pressurization is less than 1 MPa.

  In a specific aspect of the method of manufacturing a connection structure according to the present invention, no pressure is applied in the step of disposing the second connection target member and the step of forming the first connection portion. The weight of the second connection target member is added to the conductive paste layer of the second connection target member, and pressurization is not performed in the step of arranging the third connection target member and the step of forming the second connection portion. The weight of the third connection target member is added to the second conductive paste layer.

  The average particle diameter of the solder particles contained in the second conductive paste is preferably 0.5 μm or more and 100 μm or less. The average particle diameter of the solder particles contained in the first conductive paste is preferably 0.5 μm or more and 100 μm or less. The content of the solder particles in the second conductive paste is preferably 10% by weight or more and 80% by weight or less. The content of the solder particles in the first conductive paste is preferably 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, an end portion of the second electrode on the upper surface of the second connection target member and the second electrode in the main surface direction of the second connection target member The distance between the lower surface of the second connection target member and the end of the second electrode is 0 μm or more and 1000 μm or less.

  In a specific aspect of the method of manufacturing a connection structure according to the present invention, an end portion of the second electrode on the upper surface of the second connection target member and the second electrode in the main surface direction of the second connection target member The distance between the lower surface of the second connection target member and the end of the second electrode is 10 μm or more and 1000 μm or less.

  In a specific aspect of the method of manufacturing a connection structure according to the present invention, the third 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 for manufacturing a connection structure according to the present invention, the second connection target member is a rigid substrate excluding a rigid flexible substrate, and the third connection target member is a resin film, a flexible print It is a substrate, 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 electrode width of the third 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, and the inter-electrode width of the third electrode is 50 μm or more and 1000 μm or less.

  In the method of manufacturing a connection structure according to the present invention, when the laminate is used, the second conductive paste is used on the upper surface of the second connection target member in the laminate to form a second conductive material. In the step of disposing a paste layer, and on the upper surface of the second conductive paste layer, the third connection target member is faced from the lower surface side, and the second electrode on the upper surface and the third electrode on the lower surface face each other And heating the second conductive paste layer to a temperature higher than the melting point of the solder particles contained in the second conductive paste layer and higher than the curing temperature of the thermosetting component. A second connection portion connecting the second connection target member and the third connection target member is formed by the second conductive paste layer, and the second electrode on the upper surface and the lower surface And a second electrode in the second connection portion And a step of electrically connecting by means of the projection, and as the second connection target member, the second electrode does not face each other on the upper surface and the lower surface of the second connection target member, Since the second connection target member in which the position of the second electrode is shifted is used on the upper surface and the lower surface of the second connection target member, solder particles can be efficiently disposed between the electrodes. It is possible to improve the continuity reliability between the two.

  In the method of manufacturing a connection structure according to the present invention, the first conductive paste is applied on the upper surface of the first connection target member, and the first conductive paste layer is disposed; Arranging the second connection target member on the upper surface of the first conductive paste layer so that the first electrode on the upper surface faces the second electrode on the lower surface from the lower surface side; By heating the first conductive paste layer above the melting point of the solder particles contained in the first conductive paste layer and above the curing temperature of the thermosetting component, the first connection target member and the second connection target member The first connection portion connecting the connection target member is formed of the first conductive paste layer, and the first electrode on the upper surface and the second electrode on the lower surface are the first connection portion. Electrically connecting by the first solder portion in the first connection portion; Placing a second conductive paste layer on the upper surface of the second connection target member using the second conductive paste, and forming the third conductive paste layer on the upper surface of the second conductive paste layer Arranging the connection target member so that the second electrode on the upper surface faces the third electrode on the lower surface from the lower surface side, and the melting point or more of the solder particles contained in the second conductive paste layer And the second connection portion connecting the second connection target member and the third connection target member by heating the second conductive paste layer to a temperature higher than the curing temperature of the thermosetting component. Is formed by the second conductive paste layer, and the second electrode on the upper surface and the third electrode on the lower surface are electrically connected by the second solder portion in the second connection portion. And, as the second connection target member, The second electrode does not face each other on the upper surface and the lower surface of the second connection target member, and the position of the second electrode is shifted on the upper surface and the lower surface of the second connection target member Since the second connection target member is used, solder particles can be efficiently disposed between the electrodes, and conduction reliability between the electrodes can be enhanced.

FIG. 1 is a partially cutaway front cross-sectional view schematically showing a connection structure obtained by the method of manufacturing a connection structure according to an embodiment of the present invention. FIGS. 2 (a) to 2 (c) are partial cutaway front cross-sectional views for explaining each step of the method for manufacturing a connection structure according to the embodiment of the present invention. FIG.3 (a)-(c) are partial notch front sectional drawings for demonstrating each process of the manufacturing method of the connection structure which concerns on one Embodiment of this invention. FIG. 4 is a partial cutaway front cross-sectional view showing a modified example of the connection structure. FIG. 5 is a partially cutaway front cross-sectional 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 a broad aspect of the present invention, in the method of manufacturing a connection structure according to the present invention,
(B) a second conductive paste containing a thermosetting component and a plurality of solder particles,
(A '/ C' / D ') A first connection target member having at least one first electrode on the upper surface, and at least one second electrode on the upper surface, and at least one second electrode A second connection target member on the lower surface is connected by a first connection portion including conductive particles, and the first electrode on the upper surface and the second electrode on the lower surface are connected to the conductive particles. A laminate electrically connected by the first conductive portion derived therefrom, and
(E) A third connection target member having at least one third electrode on the lower surface is used.

  In the present invention, in the case of using the second conductive paste of (B), (A ′ / C ′ / D ′) and (E) described above, the laminate and the second connection target member, the second connection is preferable. As a target member, the second electrode is not opposed on the upper surface and the lower surface of the second connection target member, and the position of the second electrode is on the upper surface and the lower surface of the second connection target member The second connection target member which is shifted is used.

The method for producing a connection structure according to the present invention uses the second conductive paste of (B), (A '/ C' / D ') and (E) described above, the laminate, and the second connection target member. In case,
(Fourth Step) A step of disposing a second conductive paste layer using the second conductive paste on the upper surface of the second connection target member in the laminate.
(Fifth Step) The third connection target member is placed on the upper surface of the second conductive paste layer so that the second electrode on the upper surface faces the third electrode on the lower surface from the lower surface side Placing in
(Sixth Step) The second conductive paste layer is heated by heating the second conductive paste layer to a temperature equal to or higher than the melting point of the solder particles contained in the second conductive paste layer and equal to or higher than a curing temperature of the thermosetting component. A second connection portion connecting the connection target member and the third connection target member is formed of the second conductive paste layer, and the second electrode on the upper surface and the third on the lower surface are formed. Electrically connecting the first and second electrodes by the second solder portion in the second connection portion;
Equipped with

  In the present invention, when the second conductive paste of (B), (A ′ / C ′ / D ′) and (E), the laminate and the second connection target member described above are used, the laminate is It may be obtained through first, second and third steps described later, or may not be obtained through first, second and third steps described later.

In a broad aspect of the present invention, a method of manufacturing a connection structure according to the present invention is:
(A) a first conductive paste containing a thermosetting component and a plurality of solder particles,
(B) a second conductive paste containing a thermosetting component and a plurality of solder particles,
(C) a first connection target member having at least one first electrode on the upper surface,
(D) a second connection target member having at least one second electrode on the upper surface and at least one second electrode on the lower surface;
(E) a third connection target member having at least one third electrode on the lower surface,
Use

  In the present invention, when the conductive paste and the connection target member of the above (A), (B), (C), (D) and (E) are used, the second connection target member is the second connection target member. The second connection target in which the second electrode is not opposed on the upper surface and the lower surface of the connection target member, and the position of the second electrode is shifted on the upper surface and the lower surface of the second connection target member Use a member.

In the case of using the conductive paste of the above (A), (B), (C), (D) and (E) and the connection target member, the method for producing a connection structure according to the present invention,
(First Step) A step of applying the first conductive paste on the upper surface of the first connection target member and arranging a first conductive paste layer;
(Second Step) On the upper surface of the first conductive paste layer, the second connection target member is placed from the lower surface side so that the first electrode on the upper surface and the second electrode on the lower surface face each other Placing in
(Third Step) The first conductive paste layer is heated by heating the first conductive paste layer to a temperature equal to or higher than the melting point of the solder particles contained in the first conductive paste layer and equal to or higher than a curing temperature of the thermosetting component. A first connection portion connecting the connection target member and the second connection target member is formed of the first conductive paste layer, and the first electrode on the upper surface and the second on the lower surface are formed. Electrically connecting the first and second electrodes with the first and second electrodes;
(Fourth Step) A step of disposing a second conductive paste layer on the upper surface of the second connection target member using the second conductive paste
(Fifth Step) The third connection target member is placed on the upper surface of the second conductive paste layer so that the second electrode on the upper surface faces the third electrode on the lower surface from the lower surface side Placing in
(Sixth Step) The second conductive paste layer is heated by heating the second conductive paste layer to a temperature equal to or higher than the melting point of the solder particles contained in the second conductive paste layer and equal to or higher than a curing temperature of the thermosetting component. A second connection portion connecting the connection target member and the third connection target member is formed of the second conductive paste layer, and the second electrode on the upper surface and the third on the lower surface are formed. Electrically connecting the first and second electrodes by the second solder portion in the second connection portion;
Equipped with

  In the present invention, since the above configuration is provided, a plurality of solder particles are easily collected between the electrodes, and the plurality of solder particles can be efficiently arranged on the electrodes (lines). In particular, a plurality of solder particles can be efficiently disposed between the second electrode on the upper surface and the third electrode on the lower surface. 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.

  Specifically, since the position of the second electrode is shifted between the upper surface and the lower surface of the second connection target member, heat is applied by the second electrode of the lower surface when the second conductive paste layer is thermally cured. Not dissipated. Therefore, the temperature of the second conductive paste layer between the second electrode on the upper surface and the third electrode on the lower surface can be sufficiently raised, and the melt viscosity of the second conductive paste layer is sufficiently lowered. The solder particles can be effectively collected between the upper second electrode and the lower third electrode.

  On the other hand, when the position of the second electrode is not shifted between the upper surface and the lower surface of the second connection target member, heat is dissipated by the second electrode of the lower surface when the second conductive paste layer is thermally cured. Be done. For this reason, the temperature of the second conductive paste layer between the second electrode on the upper surface and the third electrode on the lower surface is not sufficiently high, and the melt viscosity of the second conductive paste layer is not sufficiently low. The solder particles tend not to collect effectively between the second electrode on the upper surface and the third electrode on the lower surface.

  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 members to be connected, convection of the conductive paste is generated by reducing the viscosity of the conductive paste by heat. Methods etc. In this method, convection is generated by the difference in heat capacity between the electrode on the surface of the connection target member and the other surface members, the method of causing the water of the connection target member to generate convection as water vapor by heat, and upper and lower connection The method etc. which generate | occur | produce a convection by temperature difference with an 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 150 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 to the first conductive paste layer in the step of arranging the second connection target member and the step of forming the first connection portion. Is performed by applying pressure in at least one of the step of disposing the second connection target member and the step of arranging the second connection target member or adding the weight of the second connection target member And, in both of the step of arranging the second connection target member and the step of forming the first connection portion, it is preferable that a pressure of pressurization is less than 1 MPa. By not applying a pressure of 1 MPa or more, aggregation of the solder particles is considerably promoted. From the viewpoint of suppressing the warpage 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 first connection portion In both of the step of applying pressure and disposing the second connection target member and the step of forming the first connection portion, the pressure of the pressure may be less than 1 MPa. 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 first connection portion. Pressurization may be performed in both the step of arranging the second connection target member and the step of forming the first connection portion. 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 to the second conductive paste layer in the step of arranging the third connection target member and the step of forming the second connection portion. Is performed by applying pressure in at least one of the step of placing the third connection target member and the step of forming the second connection portion, or adding a weight of the third connection target member or And, in both of the step of arranging the third connection target member and the step of forming the second connection portion, the pressure of pressurization is preferably less than 1 MPa. By not applying a pressure of 1 MPa or more, aggregation of the solder particles is considerably promoted. From the viewpoint of suppressing the warpage 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 third connection target member and the step of forming the second connection portion In both of the step of applying pressure and disposing the third connection target member and the step of forming the second connection portion, the pressure of the pressure may be less than 1 MPa. When pressing is performed, pressing may be performed only in the step of arranging the third connection target member, or may be performed only in the step of forming the second connection portion. Pressurization may be performed in both the step of arranging the third connection target member and the step of forming the second connection portion. 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 to the first conductive paste layer in the step of arranging the second connection target member and the step of forming the first connection portion. Preferably, the weight of the second connection target member is added, and in the step of arranging the second connection target member and the step of forming the first connection portion, the first conductive paste layer is It is preferable not to apply an applied pressure that exceeds the force of the weight of the second connection target member. Furthermore, in the step of arranging the third connection target member and the step of forming the second connection portion, no pressurization is performed, and the second conductive paste layer is formed of the third connection target member. It is preferable that weight is added, and in the step of arranging the third connection target member and the step of forming the second connection portion, the weight of the third connection target member is included in the second conductive paste layer. Preferably, no overpressure is applied which exceeds the force of. In these cases, the thickness of the solder portion can be increased more effectively, and a plurality of solder particles are more likely to be collected between the electrodes, and the plurality of solder particles can be made more efficient on the electrodes (lines). It can be arranged. 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.

  In addition, it is necessary to use a conductive paste, not a conductive film, in order to efficiently dispose a plurality of solder particles on the electrode and to considerably reduce the amount of solder particles disposed in the area where the electrode is not formed. The inventor found that there was.

  Furthermore, in the step of arranging the second connection target member and the step of forming the first connection portion, no pressure is applied, and the weight of the second connection target member is added to the first conductive paste layer. The solder particles arranged in the region (space) in which the electrode is not formed before the connection portion is formed are more easily collected between the first electrode and the second electrode, If the weight of the third connection target member is added to the second conductive paste layer without applying pressure in the step of arranging the third connection target member and the step of forming the second connection portion, The solder particles arranged in the region (space) where the electrode is not formed before the connection portion is formed are more easily collected between the first electrode and the second electrode, and the plurality of solder particles are More effective on (line) Also, the present inventors have found that it is possible to arranged. In the present invention, not the conductive film but the conductive paste is used, and the weight of the second connection target member is added to the first conductive paste layer without applying pressure. Alternatively, the effect of the present invention can be further enhanced by adopting a combination of a configuration in which the weight of the third connection target member is added to the second conductive paste layer without applying pressure. It has great meaning to get 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, FIG. 1 schematically shows a connection structure obtained by the method of manufacturing a connection structure according to an embodiment of the present invention in a partially cutaway front cross-sectional view.

  The connection structure 1 shown in FIG. 1 includes a first connection target member 2, a second connection target member 3, a third connection target member 4, a first connection portion 5, and a second connection portion. And 6.

  The first connection portion 5 connects the first connection target member 2 and the second connection target member 3. The first connection portion 5 is formed of a first conductive paste containing a thermosetting component and a plurality of solder particles. The first connection portion 5 is a cured product of the first conductive paste. However, the first connection portion 5 may be formed of a conductive material containing conductive particles, and the conductive particles may not be solder particles. In addition, the conductive material may be a conductive paste, may be a conductive film, may not contain a thermosetting component, and may contain a thermoplastic component.

  The second connection portion 6 connects the second connection target member 3 and the third connection target member 4. The second connection portion 6 is formed of a second conductive paste containing a thermosetting component and a plurality of solder particles. The second connection portion 6 is a cured product of the second conductive paste.

  The first connection portion 5 has a first solder portion 5A in which a plurality of solder particles are gathered and joined together, and a first cured product portion 5B in which a thermosetting component is thermally cured. In the case where the first connection portion is formed of a conductive material including a thermosetting component and a plurality of conductive particles, the first connection portion is a first conductivity derived from the plurality of conductive particles. And a first cured product portion in which the thermosetting component is thermally cured.

  The first connection target member 2 has a plurality of first electrodes 2a on the top surface. The second connection target member 3 has a plurality of second electrodes 3a on the lower surface. The first electrode 2a on the upper surface and the second electrode 3a on the lower surface are electrically connected by the first solder portion 5A. Therefore, the first connection target member 2 and the second connection target member 3 are electrically connected by the first solder portion 5A. In addition, in the first connection portion 5, a region (the first cured product portion 5B portion) different from the first solder portion 5A gathered between the first electrode 2a on the upper surface and the second electrode 3a on the lower surface In) there is no solder. There is no solder separated from the first solder portion 5A in a region (first cured product portion 5B portion) different from the first solder portion 5A. If the amount is small, the solder is present in a region (first cured product portion 5B portion) different from the first solder portion 5A collected between the first electrode 2a and the second electrode 3a. It may be

  The second connection portion 6 includes a second solder portion 6A in which a plurality of solder particles are gathered and joined to one another, and a second cured product portion 6B in which a thermosetting component is thermally cured.

  The second connection target member 3 has a plurality of second electrodes 3 b on the top surface. The third connection target member 4 has a plurality of third electrodes 4 a on the lower surface. The second electrode 3b on the upper surface and the third electrode 4a on the lower surface are electrically connected by the second solder portion 6A. Therefore, the second connection target member 3 and the third connection target member 4 are electrically connected by the second solder portion 6A. In the second connection portion 6, a region (the second cured product portion 6B portion) different from the second solder portion 6A gathered between the second electrode 3b on the upper surface and the third electrode 4a on the lower surface In) there is no solder. In a region (second cured product portion 6B portion) different from the second solder portion 6A, there is no solder separated from the second solder portion 6A. If the amount is small, the solder is present in a region (the second cured product portion 6B portion) different from the second solder portion 6A collected between the second electrode 3b and the third electrode 4a. It may be

  As shown in FIG. 1, in the connection structure 1, a plurality of solder particles gather between the first electrode 2a on the upper surface and the second electrode 3a on the lower surface, and after the plurality of solder particles are melted, the solder is The melt of the particles wets and spreads on the surface of the electrode and then solidifies to form a first solder portion 5A. In the present embodiment, the thickness of the first solder portion 5A located between the first electrode 2a on the upper surface and the second electrode 3a on the lower surface in the connection structure 1 is the first conductive paste. It is larger than the average particle size of the plurality of solder particles contained. For this reason, the contact area of the 1st solder part 5A and the 1st electrode 2a, and the 1st solder part 5A and the 2nd electrode 3a becomes large. By using the solder particles, the contact between the first solder portion 5A and the first electrode 2a as compared to the case where conductive particles whose conductive outer surface is a metal such as nickel, gold or copper is used The area and the contact area between the first solder portion 5A and the second electrode 3a increase. This also increases the conduction reliability and the connection reliability in the connection structure 1.

  Further, as shown in FIG. 1, in the connection structure 1, a plurality of solder particles gather between the second electrode 3 b on the upper surface and the third electrode 4 a on the lower surface, and the plurality of solder particles melt. After the melt of the solder particles wets and spreads the surface of the electrode and then solidifies, the second solder portion 6A is formed. In the present embodiment, the thickness of the second solder portion 6A located between the second electrode 3b on the upper surface and the third electrode 4a on the lower surface in the connection structure 1 is the second conductive paste. It is larger than the average particle size of the plurality of solder particles contained. Therefore, the contact area between the second solder portion 6A and the second electrode 3b, and between the second solder portion 6A and the third electrode 4a is increased. By using the solder particles, the contact between the second solder portion 6A and the second electrode 3b as compared with the case where conductive particles whose outer surface is a metal such as nickel, gold or copper is used. The area and the contact area between the second solder portion 6A and the third electrode 4a increase. 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.

  Next, a method of manufacturing a connection structure according to an embodiment of the present invention will be described.

  First, a first conductive paste containing a thermosetting component 11B and a plurality of solder particles 11A is prepared. Further, the first connection target member 2 having the first electrode 2a on the top surface is prepared.

  As shown to Fig.2 (a), the 1st conductive paste layer 11 is arrange | positioned using the said 1st conductive paste on the upper surface of the 1st connection object member 2 (1st process). The first conductive paste layer 11 is disposed on the surface of the upper surface of the first connection target member 2 on which the first electrode 2 a is provided. After the placement of the first conductive paste layer 11, the solder particles 11A are placed both on the first electrode 2a (line) and on the region (space) where the first electrode 2a is not formed. There is.

  The arrangement method of the first conductive paste layer 11 and the second conductive paste layer 12 described later is not particularly limited, but application by a dispenser, screen printing, discharge by an inkjet device, and the like can be mentioned.

  In addition, a second connection target member 3 having the second electrode 3a on the lower surface and the second electrode 3b on the upper surface is prepared.

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

  Next, the first conductive paste layer 11 is heated to a temperature equal to or higher than the melting point of the solder particles 11A and to a temperature equal to or higher than the curing temperature of the thermosetting component 11B (third step). That is, the first conductive paste layer 11 is heated to a temperature lower than the melting point of the solder particles 11A contained in the first conductive paste layer 11 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). 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 first connection portion 5 connecting the first connection target member 2 and the second connection target member 3 is made of the first conductive paste layer 11. Form. The first connection portion 5 is formed of the first conductive paste layer 11, and the plurality of solder particles 11A are joined to form the first solder portion 5A, and the thermosetting component 11B is thermally cured. A cured product portion 5B of 1 is formed. 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 addition, a second conductive paste including a thermosetting component 12B and a plurality of solder particles 12A is prepared.

  As shown to Fig.3 (a), the 2nd conductive paste layer 12 is arrange | positioned using the said 2nd conductive paste on the upper surface of the 2nd connection object member 3 (4th process). The second conductive paste layer 12 is disposed on the surface of the upper surface of the second connection target member 3 on which the second electrode 3 b is provided. After the placement of the second conductive paste layer 12, the solder particles 12A are placed both on the second electrode 3b (line) and on the area (space) where the second electrode 3b is not formed. There is.

  In addition, the third connection target member 4 having the third electrode 4a on the lower surface is prepared.

  Next, as shown in FIG. 3B, in the second conductive paste layer 12 on the upper surface of the second connection target member 3, the second connection target member 3 side of the second conductive paste layer 12 and The third connection target member 4 is disposed from the lower surface side on an opposite surface (upper surface) (fifth step). The third connection target member 4 is disposed on the upper surface of the second conductive paste layer 12 from the side of the third electrode 4 a on the lower surface. At this time, the second electrode 3 b on the upper surface and the third electrode 4 a on the lower surface are opposed to each other.

  Next, the second conductive paste layer 12 is heated to a temperature equal to or higher than the melting point of the solder particles 12A contained in the second conductive paste layer 12 and equal to or higher than the curing temperature of the thermosetting component 12B (sixth step). That is, the second conductive paste layer 12 is heated to a temperature that is lower than the melting point of the solder particles 12A and the curing temperature of the thermosetting component 12B. At the time of this heating, the solder particles 12A present in the region where the electrode is not formed gather between the second electrode 3b and the third electrode 4a (self-aggregation effect). Further, in the present embodiment, since the conductive paste is used instead of the conductive film, the solder particles 12A are effectively collected between the second electrode 3b and the third electrode 4a. Also, the solder particles 12A melt and bond to each other. In addition, the thermosetting component 12B is thermally cured. As a result, as shown in FIG. 3C, the second connection portion 6 connecting the second connection target member 3 and the third connection target member 4 is made of the second conductive paste layer 12. Form. The second connection portion 6 is formed of the second conductive paste layer 12, and the plurality of solder particles 12A are joined to form the second solder portion 6A, and the thermosetting component 12B is thermally cured. Two cured product portions 6B are formed. If the solder particles 12A move sufficiently, the movement of the solder particles 12A not located between the second electrode 2b and the third electrode 4a starts, and then the second electrode 2b and the third electrode It is not necessary to keep the temperature constant until the movement of the solder particles 12A is completed between 4a.

  In the present embodiment, the amount of solder can be increased in the plurality of second solder portions 6A. This is because the second electrode 3a and the second electrode 3b do not face each other on the upper surface and the lower surface of the second connection target member 3, and the second electrode 3a and the second electrode 3b do not face each other. This is because the positions of the electrode 3a and the second electrode 3b are shifted. The second electrode 3 a and the second electrode 3 b do not face each other via the second connection target member main body, and the second electrode 3 a and the second connection target member 3 have the second electrode 3 a and the second The positions of the two electrodes 3b are shifted. There is no second electrode 3 b on the upper surface above the second electrode 3 a on the lower surface. Below the second electrode 3b on the upper surface, there is no second electrode 3a on the lower surface. Therefore, when the solder particles 12A on the upper second electrode 3b are moved by heating, heat is less likely to be dissipated below the upper second electrode 3b, and the viscosity of the second conductive paste layer 12 is sufficient. It is easy to fall down. As a result, the solder particles 12A move efficiently.

  Temporarily, the second electrodes 103a and 103b face each other on the upper and lower surfaces of the second connection target member 103, and the positions of the second electrodes 103a and 103b on the upper and lower surfaces of the second connection target member 103 If the two do not shift, it is easy to obtain a connection structure 101 as shown in FIG. The connection structure body 101 includes a first connection target member 102, a second connection target member 103, a third connection target member 104, a first connection portion 105, and a second connection portion 106. . The first connection target member 102 has a plurality of first electrodes 102 a on the top surface. The second connection target member 103 has a plurality of second electrodes 103 a on the lower surface, and has a plurality of second electrodes 103 b on the upper surface. The third connection target member 104 has a plurality of third electrodes 104 a on the lower surface. The first connection portion 105 has a first solder portion 105A and a first cured product portion 105B. The second connection portion 106 includes a second solder portion 106A and a first cured product portion 106B.

  When obtaining the connection structure body 101, when the solder particles on the second electrode 103a on the upper surface are moved by heating, heat is easily dissipated below the second electrode 103a on the upper surface. Therefore, the temperature of the second conductive paste layer between the second electrode 103a on the upper surface and the third electrode 104a on the lower surface is not sufficiently high, and the melt viscosity of the second conductive paste layer is sufficiently low. In addition, solder particles are less likely to be effectively collected between the second electrode 103a on the upper surface and the third electrode 103b on the lower surface.

  In the main surface direction of the second connection target member, an end of the second electrode on the upper surface of the second connection target member and an end of the second electrode on the lower surface of the connection target member of the second The distance D (see FIG. 1) is 0 μm or more, preferably more than 0 μm, more preferably 0.1 μm or more, still more preferably 1 μm or more, still more preferably 3 μm or more, still more preferably 5 μm or more, still more preferably 10 μm or more, still more preferably 50 μm or more, particularly preferably 100 μm or more, particularly preferably 150 μm or more, most preferably 200 μm or more, preferably 1000 μm or less. As the distance D is larger, the heat dissipation by the second electrode on the lower surface can be further prevented. The main surface direction of the second connection target member is generally a direction orthogonal to the stacking direction of the first, second, and third connection target members in the obtained connection structure.

  In the connection structure 1 shown in FIG. 1, all of the first solder portions 5A are located in the facing region between the first and second electrodes 2a and 3a, and the second solder portions All of 6A are located in the facing area between the second and third electrodes 3b and 4a. The connection structure 1X of the modification shown in FIG. 4 differs from the connection structure 1 shown in FIG. 1 only in the first and second connection portions 5X and 6X. The first and second connection parts 5X and 6X have first and second solder parts 5XA and 6XA and first and second hardened material parts 5XB and 6XB. Like the connection structure 1X, most of the first solder portions 5XA are located in the area where the first and second electrodes 2a and 3a are opposed to each other, and a part of the first solder portions 5XA is It may be protruded to the side from the field which the 1st and 2nd electrodes 2a and 3a have opposed. The first solder portion 5XA protruding laterally from the opposing region of the first and second electrodes 2a and 3a is a part of the first solder portion 5XA, and from the first solder portion 5XA It is not a distant solder. Like the connection structure 1X, most of the second solder portions 6XA are located in the area where the second and third electrodes 3b and 4a are opposed, and a part of the second solder portions 6XA is It may be protruded to the side from the field which the 2nd, 3rd electrodes 3b and 4a have opposed. The second solder portion 6XA protruding laterally from the opposing region of the second and third electrodes 3b and 4a is a part of the second solder portion 6XA, and from the second solder portion 6XA It is not a distant solder. 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 usage amount of the solder particles is large, it is easy to make the thickness of the solder portion located between the electrodes in the connection structure larger than the average particle diameter of the solder particles contained in the conductive paste.

  In the present embodiment, no pressurization is performed in the second step and the third step, and no pressurization is performed in the fifth step and the sixth step. In the present embodiment, the weight of the second connection target member 3 is added to the first conductive paste layer 11, and the weight of the third connection target member 4 is added to the second conductive paste layer 12. Further, in the present embodiment, not the conductive film but the conductive paste is used. Therefore, at the time of formation of the first and second connection parts 5 and 6, the solder particles 11A are effectively collected between the first electrode 2a and the second electrode 3a, and the solder particles 12A are Effectively gather between the third electrode 3a and the third electrode 4a. As a result, the thickness of the first solder portion 5A between the first electrode 2a and the second electrode 3a and the thickness of the second solder portion 6A between the second electrode 3b and the third electrode 4a Tends to be thicker. 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. The solder particles tend to gather between the second electrode and the third electrode if pressure is applied in at least one of the fifth step and the sixth step. The tendency for the action to be inhibited is high. This was found by the present inventor.

  Further, in the present embodiment, since pressurization is not performed, even when the connection target members are overlapped in a state where the alignment of the electrodes of the connection target members is shifted, the shift is corrected to connect the electrodes. Can (self alignment effect). This is because the area where the molten solder self-aggregated between the electrodes is in contact with the solder between the electrodes and the other components of the conductive paste is minimized in energy, so the connection is the smallest area This is because a force acts on the connection structure having alignment, which is a structure. 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 first conductive paste and the second 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. It is 1 Pa · s or more, more preferably 0.2 Pa · s or more. If the viscosity is less than the predetermined viscosity, the solder particles can be efficiently aggregated, and if the viscosity is the predetermined viscosity or more, the voids at the bonding portion are suppressed, and the spreading of the conductive paste to other than the connection portion is suppressed. Also, the uniformity of the amount of solder can be further enhanced in the plurality of solder portions.

  Thus, the connection structure 1 shown in FIG. 1 is obtained. The second process and the third process may be performed continuously, and the fifth process and the sixth process may be performed continuously. Moreover, after performing the said 2nd process, it is moved to a heating member in the state on which the 1st connection object member 2, the 1st conductive paste layer 11, and the 2nd connection object member 3 were laminated, The third step may be performed. After performing the fifth step, the second connection target member 3, the second conductive paste layer 12, and the third connection target member 4 are moved to the heating member in a state in which the second connection target member 3, the second conductive paste layer 12 and the third connection target member 4 are stacked. Step 6 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 temperatures in the third step and the sixth step are not particularly limited as long as they are equal to or higher than the melting point of the solder particles contained in the first and second conductive paste layers 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.

  From the viewpoint of further promoting the movement of the solder particles and further enhancing the manufacturing efficiency of the connection structure, when the first connection portion is formed of the first conductive paste layer, the first connection portion may be formed. The time from the start of heating of the conductive paste layer to the melting point of the solder particles contained in the first conductive paste layer is preferably 1 second or more, more preferably 2 seconds or more, preferably 300 seconds or less, more preferably Is set to 120 seconds or less, more preferably 60 seconds or less. This time is particularly preferably 2 seconds or more and 60 seconds or less.

  From the viewpoint of further promoting the movement of the solder particles and further enhancing the production efficiency of the connection structure, when the second connection portion is formed of the second conductive paste layer, the second The time from the start of heating of the conductive paste layer to the melting point of the solder particles contained in the second conductive paste layer is preferably 1 second or more, more preferably 2 seconds or more, preferably 300 seconds or less, more preferably Is set to 120 seconds or less, more preferably 60 seconds or less. This time is particularly preferably 2 seconds or more and 60 seconds 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. After the fifth step, the second connection target member or the third connection target member can be peeled off from the connection portion for the purpose of position correction and production rework. The heating temperature for performing this peeling is preferably not less than the melting point of the solder particles, more preferably the melting point (° C.) of the solder particles, in consideration of the melting points of the solder particles contained in the first and second conductive paste layers respectively. + 10 ° C. or higher. 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 and the sixth step, the entire connection structure is heated using a reflow furnace or using an oven above the melting point of the solder particles and the curing temperature of the thermosetting component. Or a method of locally heating only the connection portion of the connection structure.

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

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

  The first connection target member may have at least one first electrode. The first connection target member preferably includes a plurality of first electrodes. The second connection target member may have at least one second electrode on each of the upper surface and the lower surface. The second connection target member preferably has a plurality of second electrodes on each of the upper surface and the lower surface. The third connection target member may have at least one third electrode. The third connection target member preferably has a plurality of second electrodes.

  The first, second and third connection target members are not particularly limited. Specifically, the first, second and third connection target members include a semiconductor chip, a semiconductor package, an LED chip, an LED package, an electronic component such as a capacitor and a diode, a resin film, a printed circuit board, and a flexible print Examples include electronic components such as substrates, flexible flat cables, rigid flexible substrates, circuit substrates such as glass epoxy substrates and glass substrates, and the like. The first, second, and third connection target members are preferably electronic components.

  It is preferable that at least one of the first connection target member, the second connection target member, and the third 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. It is preferable that the said 3rd 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.

  The second connection target member is preferably a rigid substrate excluding a rigid flexible substrate, and the third connection target member is preferably a resin film, a flexible printed circuit, a rigid flexible substrate or a flexible flat cable. When the second connection target member is a rigid substrate, since the rigid substrate is hard, the second conductive paste can be arranged with high accuracy.

  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 η at 25 ° C. of the first conductive paste and the second conductive paste is preferably 10 Pa · s or more, more preferably 50 Pa · s or more, in order to arrange the solder particles more efficiently on the electrode. More preferably, it is 100 Pa · s or more, preferably 800 Pa · s or less, more preferably 600 Pa · s or less, still more preferably 500 Pa · s or less.

  The 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, the electrode width of the second electrode, and the electrode width of the third electrode are preferably 50 μm or more, from the viewpoint of enhancing the uniformity of the solder amount. More preferably, it is 75 μm or more, preferably 1000 μm 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, the inter-electrode width of the second electrode and the inter-electrode width of the third electrode are preferably 50 μm from the viewpoint of arranging the solder particles more efficiently between the electrodes. The thickness is more preferably 75 μm or more, preferably 1000 μm or less, more preferably 500 μm or less, and 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 first conductive paste preferably includes a thermosetting component and a plurality of solder particles. The second 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 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 or less. 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 (meth) acryloyl group Can be 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 preferable epoxy compound, when the connection target member is bonded, the viscosity is high, and when an impact such as conveyance is given an acceleration, the positional deviation of the connection target member can be suppressed. Furthermore, the viscosity of the conductive paste can be greatly reduced by the 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.

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

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

  From the viewpoint of arranging the solder more efficiently on the 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:
72 parts by weight of bisphenol F (containing 2,4: 1 by weight ratio of 4,4′-methylenebisphenol, 2,4′-methylenebisphenol and 2,2′-methylenebisphenol), 1,6-hexanediol 70 parts by weight of glycidyl ether and 30 parts by weight of bisphenol F-type epoxy resin ("EPICLON EXA-830 CRP" manufactured by DIC Corporation) were placed in a three-necked flask and dissolved at 150 ° C under a nitrogen flow. Thereafter, 0.1 part by weight of tetra-n-butylsulfonium bromide, which is a catalyst for addition reaction of hydroxyl group and epoxy group, is added, and the reaction product (polymer is caused by addition polymerization reaction at 150 ° C. for 6 hours under nitrogen flow. I got A).

  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 10000, and the number average molecular weight was 3500.

  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: Bisphenol F type epoxy resin, "EPICLON EXA-830 CRP" manufactured by DIC

  Thermosetting agent 1: Pentaerythritol tetrakis (3-mercaptobutyrate), Showa Denko "Karens MT PE1"

  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 recovered 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 the solder particles having the anionic polymer 1 was put into 10 g of methanol, and the obtained solder particles were subjected to ultrasonic treatment to be uniformly dispersed 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 particles 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.)

Example 1
(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) First connection structure: 20 electrodes of a copper electrode pattern with an electrode size of 500 μm × 500 μm are provided on the upper surface of the substrate so that the space between the electrodes is 1 mm, and the electrode size is 500 μm × 500 μm A glass epoxy substrate was prepared which had 20 electrodes of a copper electrode pattern on the lower surface of the substrate such that the electrodes on the upper surface and the lower surface were alternately arranged at equal intervals. In the main surface direction (direction orthogonal to the thickness direction) of the glass epoxy substrate, the distance D between the end of the electrode on the upper surface and the end of the electrode on the lower surface was 250 μm.

  In the glass epoxy substrate, the thickness of the copper electrode was 12 μm, the thickness of the solder resist was 30 μm, and the total thickness of the substrate was 0.6 mm.

  Next, prepare first and second flexible printed circuit boards (total thickness 100 μm) that have 20 electrodes of copper electrode pattern with electrode size 500 μm × 500 μm on one surface so that the space between the electrodes is 1 mm. did.

  The anisotropic conductive paste immediately after preparation is coated on the upper surface of the glass epoxy substrate by screen printing using a metal mask so as to have a thickness of 100 μm on the electrode of the glass epoxy substrate, and the first A directional conductive paste layer was formed. Next, the first flexible printed circuit was laminated on the upper surface of the first anisotropic conductive paste layer so that the electrodes face each other. At this time, no pressure was applied. The weight of the first flexible printed circuit board is added to the first anisotropic conductive paste layer. Thereafter, the solder is melted while heating on the hot plate so that the temperature of the first anisotropic conductive paste layer becomes 190 ° C., and the first anisotropic conductive paste layer is heated to 190 ° C. and 10 seconds And cured to obtain a laminate.

  The obtained laminate is inverted, and the anisotropic conductive paste immediately after preparation is applied on the upper surface by screen printing using a metal mask so as to have a thickness of 100 μm on the electrodes of the laminate, A second anisotropic conductive paste layer was formed. Next, the second flexible printed substrate was laminated on the upper surface of the second anisotropic conductive paste layer so that the electrodes face each other. At this time, no pressure was applied. The weight of the second flexible printed circuit board is added to the second anisotropic conductive paste layer. Thereafter, the solder is melted while heating on the hot plate so that the temperature of the second anisotropic conductive paste layer is 190 ° C., and the second anisotropic conductive paste layer is heated to 190 ° C. and 10 seconds. And cured to obtain a first connection structure.

(Example 2)
It has 20 electrodes of a copper electrode pattern of electrode size 500 μm × 500 μm on the upper surface so that the space between the electrodes is 750 μm, and 20 electrodes of copper electrode pattern of electrode size 500 μm × 500 μm A glass epoxy substrate provided on the lower surface of the substrate was prepared so that the electrodes on the lower surface were alternately arranged at equal intervals. In the main surface direction (direction orthogonal to the thickness direction) of the glass epoxy substrate, the distance D between the end of the electrode on the upper surface and the end of the electrode on the lower surface was 125 μm.

  Next, prepare first and second flexible printed circuit boards (total thickness 100 μm) that have 20 electrodes of copper electrode pattern of electrode size 500 μm × 500 μm on one surface so that the space between the electrodes is 750 μm. did.

  A second connection structure was obtained in the same manner as the first connection structure of Example 1, except that the above glass epoxy substrate and the first and second flexible printed circuit boards were used.

(Example 3)
It has 20 electrodes of a copper electrode pattern of electrode size 500 μm × 500 μm on the top surface so that the space between the electrodes is 500 μm, and 20 electrodes of copper electrode pattern of electrode size 500 μm × 500 μm A glass epoxy substrate provided on the lower surface of the substrate was prepared so that the electrodes on the lower surface were alternately arranged at equal intervals. In the main surface direction (direction orthogonal to the thickness direction) of the glass epoxy substrate, the distance D between the end of the electrode on the upper surface and the end of the electrode on the lower surface was 0 μm.

  Next, prepare first and second flexible printed circuit boards (total thickness 100 μm) that have 20 electrodes of copper electrode pattern of electrode size 500 μm × 500 μm on one side so that the space between the electrodes is 500 μm. did.

  A third connection structure was obtained in the same manner as the first connection structure of Example 1 except that the above glass epoxy substrate and the first and second flexible printed circuit boards were used.

(Example 4)
A first connected structure was obtained in the same manner as Example 1 except that the blending components and the blending amount of the anisotropic conductive paste were changed as shown in Table 1 below.

(Example 5)
A second connection structure was obtained in the same manner as in Example 2 except that the anisotropic conductive paste obtained in Example 4 was used.

(Example 6)
A third connected structure was obtained in the same manner as in Example 3 except that the anisotropic conductive paste obtained in Example 4 was used.

( Reference Example 7)
The 1st connection structure was obtained like Example 1 except having added the pressure of 1 Mpa at the time of heating of the 2nd conductive paste layer.

(Example 8)
A first connected structure was obtained in the same manner as Example 1 except that the blending components and the blending amount of the anisotropic conductive paste were changed as shown in Table 1 below.

(Example 9)
A second connected structure was obtained in the same manner as in Example 2 except that the anisotropic conductive paste obtained in Example 8 was used.

(Example 10)
A third connected structure was obtained in the same manner as in Example 3 except that the anisotropic conductive paste obtained in Example 8 was used.

(Example 11)
It has 20 electrodes of a copper electrode pattern of electrode size 500 μm × 500 μm on the upper surface so that the space between the electrodes is 600 μm, and 20 electrodes of copper electrode pattern of electrode size 500 μm × 500 μm A glass epoxy substrate provided on the lower surface of the substrate was prepared so that the electrodes on the lower surface were alternately arranged at equal intervals. In the main surface direction (direction orthogonal to the thickness direction) of the glass epoxy substrate, the distance D between the end of the electrode on the upper surface and the end of the electrode on the lower surface was 50 μm.

  Next, prepare first and second flexible printed circuit boards (total thickness 100 μm) that have 20 electrodes of copper electrode pattern of electrode size 500 μm × 500 μm on one side so that the space between the electrodes is 600 μm. did.

  A fourth connection structure was obtained in the same manner as the first connection structure of Example 1 except that the above glass epoxy substrate and the first and second flexible printed circuit boards were used.

(Example 12)
It has 20 electrodes of a copper electrode pattern of electrode size 500 μm × 500 μm on the upper surface so that the space between the electrodes is 520 μm, and 20 electrodes of copper electrode pattern of electrode size 500 μm × 500 μm A glass epoxy substrate provided on the lower surface of the substrate was prepared so that the electrodes on the lower surface were alternately arranged at equal intervals. In the main surface direction (direction orthogonal to the thickness direction) of the glass epoxy substrate, the distance D between the end of the electrode on the upper surface and the end of the electrode on the lower surface was 10 μm.

  Next, prepare first and second flexible printed circuit boards (total thickness 100 μm) that have 20 electrodes of copper electrode pattern of electrode size 500 μm × 500 μm on one side so that the space between the electrodes is 520 μm. did.

  A fifth connection structure was obtained in the same manner as the first connection structure of Example 1 except that the above glass epoxy substrate and the first and second flexible printed circuit boards were used.

(Example 13)
Having 20 electrodes of copper electrode pattern of electrode size 500 μm × 500 μm on the upper surface of the substrate so that a space between the electrodes is 1 mm, and 20 electrodes of copper electrode pattern of electrode size 500 μm × 500 μm, A flexible printed circuit board provided on the lower surface of the substrate was prepared so that the electrodes on the upper surface and the lower surface were alternately arranged at equal intervals. The distance D between the end of the electrode on the upper surface and the end of the electrode on the lower surface was 250 μm in the main surface direction (direction orthogonal to the thickness direction) of the flexible printed circuit.

  Further, in the flexible printed circuit, the thickness of the copper electrode was 12 μm, the thickness of the solder resist was 30 μm, and the total thickness of the substrate was 0.6 mm.

  A sixth connection structure was obtained in the same manner as in Example 1 except that the glass epoxy substrate was changed to a flexible printed circuit.

(Comparative example 1)
The same as in Example 1 except that the electrodes face each other on the upper surface and the lower surface of the glass epoxy substrate, and the positions of the electrodes on the upper surface and the lower surface of the first flexible printed circuit are not shifted. Thus, a seventh connection structure (facing the electrodes of the glass epoxy substrate) was obtained.

(Comparative example 2)
A solution was obtained by dissolving 18 parts by weight of a phenoxy resin ("YP-50S" manufactured by Nippon Steel Sumikin Chemical Co., Ltd.) in methyl ethyl ketone (MEK) so 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.

  A first connected structure was obtained in the same manner as Example 1 except that the anisotropic conductive film was used.

(Comparative example 3)
A first connected structure was obtained in the same manner as Example 1 except that the blending components and the blending amount of the anisotropic conductive paste were changed as shown in Table 1 below.

(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 solder on electrode In the cross section between the first and second flexible printed circuit boards of the obtained connection structure (cross section in the direction shown in FIG. 1), the electrode is 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 ○ 1: The area of the solder (solder particles) remaining in the hardened material apart from the solder portion disposed between the electrodes is 100% or more of the total area 100% of the solder appearing in the cross section, 5% Or less ○ 2: The area of the solder (solder particles) remaining in the cured product away from the solder part disposed between the electrodes in the total area of 100% of the solder appearing in the cross section exceeds 5%, 10 % Or less :: The area of the solder (solder particles) remaining in the cured product apart from the solder part disposed between the electrodes is over 10% in the total area 100% of the solder appearing in the cross section, 30 % Or less ×: 100% of the total area of the solder appearing in the cross section The area of the solder (solder particles) greater than 30% remaining in the cured product in away from the solder portion disposed to the machining gap

(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 50mΩ or less ○ 1: Average value of connection resistance exceeds 50mΩ, 60mΩ or less ○ 2: Average value of connection resistance exceeds 60mΩ, 70mΩ or less Δ: Average value of connection resistance is 70mΩ Exceeding 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 resin films, flexible flat cables and rigid flexible substrates were used instead of the first and second flexible printed substrates.

1, 1 X: connected structure 2: first connection target member 2a: first electrode (upper surface side)
3 ... 2nd connection object member 3a ... 2nd electrode (lower surface side)
3b second electrode (upper surface side)
4 ··· Third connection target member 4a ··· Third electrode (lower surface side)
5, 5X: first connection portion 5A, 5XA: first solder portion 5B, 5XB: first hardened body portion 6, 6X: second connection portion 6A, 6XA: second solder portion 6B, 6XB: Second cured product portion 11: first conductive paste layer 11A: solder particles 11B: thermosetting component 12: second conductive paste layer 12A: solder particles 12B: thermosetting component

Claims (15)

A first connection target member having at least one first electrode on the upper surface and at least one second electrode on the upper surface using the second conductive paste containing the thermosetting component and the plurality of solder particles A second connection target member having at least one second electrode on the lower surface is connected by a first connection portion including conductive particles, and the first electrode on the upper surface and the lower surface Third connection target using a stacked body electrically connected to a second electrode by a first conductive portion derived from the conductive particles and having at least one third electrode on the lower surface Using the members
Disposing a second conductive paste layer on the top surface of the second connection target member in the laminate using the second conductive paste;
Arranging the third connection target member on the upper surface of the second conductive paste layer so that the second electrode on the upper surface faces the third electrode on the lower surface from the lower surface side;
By heating the second conductive paste layer to a temperature equal to or higher than the melting point of the solder particles contained in the second conductive paste layer and equal to or higher than a curing temperature of the thermosetting component, the second connection target member and the A second connection portion connecting the third connection target member is formed of the second conductive paste layer, and the second electrode on the upper surface and the third electrode on the lower surface are the same. Electrically connecting with the second solder portion in the second connection portion,
In the step of arranging the third connection target member and the step of forming the second connection portion, no pressure is applied, and the weight of the third connection target member is applied to the second conductive paste layer. In at least one of the step of adding or arranging the third connection target member and the step of forming the second connection portion, pressurization is performed and the third connection target member is arranged The pressure of pressurization is less than 1 MPa in both the step of forming and the step of forming the second connection,
As the second connection target member, the second electrode is not opposed to the upper surface and the lower surface of the second connection target member, and the second electrode is not the upper surface and the lower surface of the second connection target member. The manufacturing method of a connection structure using the 2nd connection object member which the position of the electrode of 4 has shifted. Using a first conductive paste containing a thermosetting component and a plurality of solder particles, using at least one first electrode using a second conductive paste containing a thermosetting component and a plurality of solder particles Using a second connection target member having at least one second electrode on the upper surface and at least one second electrode on the lower surface using the first connection target member having the upper surface, and at least Using a third connection target member having one third electrode on the lower surface,
Applying the first conductive paste on the upper surface of the first connection target member to dispose the first conductive paste layer;
Arranging the second connection target member on the upper surface of the first conductive paste layer so that the first electrode on the upper surface and the second electrode on the lower surface face each other from the lower surface side;
By heating the first conductive paste layer to a temperature equal to or higher than the melting point of the solder particles contained in the first conductive paste layer and equal to or higher than the curing temperature of the thermosetting component, the first connection target member and the first connection target member The first connection portion connecting the two connection target members is formed of the first conductive paste layer, and the first electrode on the upper surface and the second electrode on the lower surface are the first connection portion. Electrically connecting by the first solder portion in the first connection portion;
Disposing a second conductive paste layer on the upper surface of the second connection target member using the second conductive paste;
Arranging the third connection target member on the upper surface of the second conductive paste layer so that the second electrode on the upper surface faces the third electrode on the lower surface from the lower surface side;
By heating the second conductive paste layer to a temperature equal to or higher than the melting point of the solder particles contained in the second conductive paste layer and equal to or higher than a curing temperature of the thermosetting component, the second connection target member and the A second connection portion connecting the third connection target member is formed of the second conductive paste layer, and the second electrode on the upper surface and the third electrode on the lower surface are the same. Electrically connecting with the second solder portion in the second connection portion,
In the step of arranging the second connection target member and the step of forming the first connection portion, no pressure is applied, and the weight of the second connection target member is applied to the first conductive paste layer. In at least one of the step of adding or arranging the second connection target member and the step of forming the first connection portion, pressurization is performed and the second connection target member is arranged The pressure of pressurization is less than 1 MPa both in the step of forming and the step of forming the first connection,
In the step of arranging the third connection target member and the step of forming the second connection portion, no pressure is applied, and the weight of the third connection target member is applied to the second conductive paste layer. In at least one of the step of adding or arranging the third connection target member and the step of forming the second connection portion, pressurization is performed and the third connection target member is arranged The pressure of pressurization is less than 1 MPa in both the step of forming and the step of forming the second connection,
As the second connection target member, the second electrode is not opposed to the upper surface and the lower surface of the second connection target member, and the second electrode is not the upper surface and the lower surface of the second connection target member. The manufacturing method of a connection structure using the 2nd connection object member which the position of the electrode of 4 has shifted.   From the start of heating of the second conductive paste layer to the melting point of the solder particles contained in the second conductive paste layer when the second connection portion is formed by the second conductive paste layer The method of manufacturing a connection structure according to claim 1, wherein the time of time t is 2 seconds or more and 60 seconds or less. In the step of arranging the third connection target member and the step of forming the second connection portion, no pressure is applied, and the weight of the third connection target member is applied to the second conductive paste layer. The method of manufacturing a connection structure according to claim 1 or 3 , additionally. From the start of heating of the first conductive paste layer to the melting point of the solder particles contained in the first conductive paste layer when the first connection portion is formed by the first conductive paste layer Time of 2 seconds or more and 60 seconds or less,
From the start of heating of the second conductive paste layer to the melting point of the solder particles contained in the second conductive paste layer when the second connection portion is formed by the second conductive paste layer The method for manufacturing a connection structure according to claim 2, wherein the time of time t is 2 seconds or more and 60 seconds or less. In the step of arranging the second connection target member and the step of forming the first connection portion, no pressure is applied, and the weight of the second connection target member is applied to the first conductive paste layer. Join,
In the step of arranging the third connection target member and the step of forming the second connection portion, no pressure is applied, and the weight of the third connection target member is applied to the second conductive paste layer. The method of manufacturing a connection structure according to claim 2 or 5 , additionally. The manufacturing method of the connection structure of any one of Claim 1, 3 and 4 whose average particle diameter of the said solder particle contained in a said 2nd electrically conductive paste is 0.5 micrometer or more and 100 micrometers or less. The average particle diameter of the solder particles contained in the first conductive paste is 0.5 μm or more and 100 μm or less,
The manufacturing method of the connection structure of any one of Claim 2, 5 and 6 whose average particle diameter of the said solder particle contained in a said 2nd conductive paste is 0.5 micrometer or more and 100 micrometers or less. The method for producing a connection structure according to any one of claims 1, 3, 4 and 7 , wherein the content of the solder particles in the second conductive paste is 10 wt% or more and 80 wt% or less. . The content of the solder particles in the first conductive paste is 10% by weight or more and 80% by weight or less,
The method for manufacturing a connection structure according to any one of claims 2, 5, 6 and 8 , wherein the content of the solder particles in the second conductive paste is 10% by weight or more and 80% by weight or less. . The end of the second electrode on the top surface of the second connection target member and the end of the second electrode on the bottom surface of the second connection target member in the main surface direction of the second connection target member The method for manufacturing a connection structure according to any one of claims 1 to 10 , wherein the distance between the two is not less than 0 μm and not more than 1000 μm. The end of the second electrode on the top surface of the second connection target member and the end of the second electrode on the bottom surface of the second connection target member in the main surface direction of the second connection target member The manufacturing method of the connection structure of Claim 11 which is 10 micrometers or more and 1000 micrometers or less. The third connection object member, a resin film, a flexible printed circuit board, a rigid flexible board or flexible flat cable, a manufacturing method of a connection structure according to any one of claims 1 to 12. The second connection target member is a rigid substrate excluding a rigid flexible substrate,
The third connection object member, a resin film, a flexible printed circuit board, a rigid flexible board or flexible flat cable, a manufacturing method of a connection structure according to any one of claims 1 to 13. 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 electrode width of the third 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 inter-electrode width of the second 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 14 , wherein an inter-electrode width of the third electrode is 50 μm or more and 1000 μm or less.

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