JP5721593B2 - Method for manufacturing connection structure - Google Patents

Description

  The present invention relates to a method for manufacturing a connection structure that electrically connects electrodes of a flexible printed circuit board and another connection target member using an anisotropic conductive paste.

  Pasty or film-like anisotropic conductive materials are widely known. In the anisotropic conductive material, a plurality of conductive particles are dispersed in a binder resin.

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

  As an example of the manufacturing method of the connection structure, in the following Patent Document 1, a first circuit member having a first circuit electrode and a second circuit electrode are provided, and a tape carrier package or a flexible printed circuit board is configured. A method of manufacturing a connection structure is disclosed in which a second circuit member is connected with an anisotropic conductive material in a state where the first circuit electrode and the second circuit electrode are arranged to face each other. .

  In addition, as an example of the method for applying the anisotropic conductive paste, in Patent Document 2 below, each mount portion for mounting a semiconductor chip or an electronic component or a part of the mount portion is recessed from the upper surface. In a lead frame or a printed circuit board or the like, a mask plate in which a hole is formed in each mount portion on the upper surface thereof, and a downward bulge portion in a portion corresponding to the recessed mount portion of the mask plate The screen printing is performed by supplying the conductive paste to the upper surface of the mask plate, and then moving the squeegee disposed on the upper surface side of the mask plate while pressing and contacting the upper surface of the mask plate. The law is disclosed.

JP 2005-235530 A JP 2003-80859 A

  In the manufacturing method of the conventional connection structure as described in Patent Document 1, in the obtained connection structure, the end portions of the first circuit electrode and the second circuit electrode serve as separation starting points, There is a problem that peeling between the circuit member and the second circuit member is likely to occur. That is, there is a problem that the connection reliability of the obtained connection structure is low.

  In addition, the conventional connection structure manufacturing method has a problem that the anisotropic conductive material easily spreads to an unintended region. For example, many anisotropic conductive materials may spread and spread in a region on the side of the electrode, that is, a region where there is no electrode. Furthermore, as a result of the anisotropic conductive material being wetted and spread to unintended areas, the resulting connection structure may be contaminated by a cured product layer obtained by curing the anisotropic conductive material.

  Further, as described in Patent Document 2, in the method for manufacturing a connection structure using a conventional screen printing method, if there is a convex portion on the surface of a connection target member on which the conductive paste is screen-printed, the convex portion As a result, the arrangement of the screen printing plate is hindered, or the interval between the screen printing plate and the connection target member needs to be increased.

  With respect to such a problem, in Patent Document 2, a screen printing plate is devised. Conventionally, it has been studied to devise a table on which a connection target member is placed. However, in these cases, it is necessary to produce a plurality of screen printing plates or to change the design of the table in accordance with the type of member to be connected. For this reason, the manufacturing cost of a connection structure becomes high. Furthermore, when the convex portion on the surface of the connection target member is large, it may be difficult to apply the conductive paste accurately and uniformly even if the screen printing plate or the table is devised.

  Furthermore, when the object to which the conductive paste is applied is a flexible printed board, the electrode height of the flexible printed board is higher than that of the glass substrate. Therefore, the screen printing method applies the conductive paste accurately and uniformly. There is a problem that it is much more difficult to do.

  The objective of this invention is providing the manufacturing method of the connection structure which can arrange an anisotropic conductive material layer efficiently and accurately, and can improve connection reliability.

  A limited object of the present invention is to provide a connection structure in which a cured layer obtained by curing an anisotropic conductive material is difficult to be disposed in an unintended region, and contamination due to the cured layer obtained by curing the anisotropic conductive material can be suppressed. It is to provide a manufacturing method.

  According to a wide aspect of the present invention, an anisotropy comprising a curable component and conductive particles on the first electrode of the flexible printed circuit board using the flexible printed circuit board having the first electrode on the surface. Using the conductive paste to dispose the anisotropic conductive material layer and using the second connection target member having the second electrode on the surface, the first electrode and the second electrode are opposed to each other. Then, the step of laminating the flexible printed circuit board and the second connection target member via the anisotropic conductive material layer, and curing the anisotropic conductive material layer to form a cured product layer A step of disposing the anisotropic conductive material layer, applying the anisotropic conductive paste from the dispenser while moving the dispenser on the first electrode, End of application The anisotropic conductive paste is applied more in at least one application area of the minute area than in the application area between the application start area and the application end area. A manufacturing method is provided.

  In a specific aspect of the method for manufacturing a connection structure according to the present invention, the movement direction of the dispenser is changed in at least one of the application start area and the application end area.

  In another specific aspect of the method for manufacturing a connection structure according to the present invention, the movement direction of the dispenser is 30 degrees or more and 180 degrees in at least one of the application start area and the application end area. Change the following.

  In another specific aspect of the method for manufacturing the connection structure according to the present invention, the dispenser is moved in a V shape or a U shape in at least one of the application start region and the application end region. Change direction.

  In another specific aspect of the method for manufacturing a connection structure according to the present invention, one edge of the cured product layer is formed by the anisotropic conductive paste applied at the start of coating, The other edge portion is formed by the anisotropic conductive paste applied at the end of the application, and at least one of the one edge portion and the other edge portion of the cured material layer is set to one of the cured material layers. The abundance of the cured product layer is increased compared to the central portion of the cured product layer between the edge and the other edge.

  In still another specific aspect of the method for manufacturing a connection structure according to the present invention, at least one of the side more than the outer peripheral side of the flexible printed board and the side more than the outer peripheral side of the second connection target member. Thus, a fillet of the cured product layer is formed in at least a part of the outer peripheral side surface.

  In another specific aspect of the method for manufacturing a connection structure according to the present invention, a fillet of the cured product layer is formed on at least one of the one edge and the other edge of the cured product layer.

  In still another specific aspect of the method for manufacturing a connection structure according to the present invention, one edge and the other edge of the cured product layer, and one edge and the other edge of the cured product layer, The fillet by the said hardened | cured material layer is formed in the center part between, The outer periphery of the said flexible printed circuit board of the said fillet in the one edge part of the said hardened | cured material layer, and the other edge or the said 2nd connection object member The protrusion distance from the side surface is the outer circumference of the flexible printed circuit board or the second connection target member of the fillet at the center of the cured product layer between one edge and the other edge of the cured product layer. Make it larger than the protruding distance from the side.

  In another specific aspect of the method for manufacturing a connection structure according to the present invention, in the application region between the region of the application start portion and the region of the application end portion, the direction in the direction orthogonal to the movement direction of the dispenser. The anisotropic conductive paste is applied from the dispenser while moving the dispenser on the first electrode in a state where the position of the dispenser is shifted to the edge side from the center of the first electrode.

  In still another specific aspect of the method for manufacturing a connection structure according to the present invention, the flexible printed circuit board has the protruding first electrode on the surface, and the protruding height is higher than that of the first electrode. Has a large protruding electronic component on the surface.

  In the manufacturing method of the connection structure according to the present invention, a curable component and conductive particles are included on the first electrode of the flexible printed board using the flexible printed board having the first electrode on the surface. Using the anisotropic conductive paste to dispose the anisotropic conductive material layer, and using the second connection target member having the second electrode on the surface, the first electrode and the second electrode; Facing each other, laminating the flexible printed circuit board and the second connection target member via the anisotropic conductive material layer, curing the anisotropic conductive material layer, and a cured product layer Forming the anisotropic conductive material layer, and applying the anisotropic conductive paste from the dispenser while moving the dispenser on the first electrode. Conductive material Layers can be arranged efficiently and accurately. Furthermore, in the manufacturing method of the connection structure according to the present invention, the application start portion region and the application end portion region are at least one of the application start portion region and the application end portion region. Since the anisotropic conductive paste is applied in a larger amount than the intermediate application region, the connection reliability between the flexible printed circuit board and the second connection target member can be increased.

1A to 1C are partial cutaway cross-sectional views schematically showing a connection structure obtained by a method for manufacturing a connection structure according to an embodiment of the present invention. 2A and 2B are a plan view and a cross-sectional view schematically showing a flexible printed board used in the method for manufacturing a connection structure according to an embodiment of the present invention. 3 (a1), (a2), (a3), (b), and (c) are partially cutaway cross-sectional views for explaining the respective steps of the connection structure manufacturing method according to an embodiment of the present invention. is there. FIG. 4 is a schematic diagram for explaining the movement direction of the dispenser in the method for manufacturing the connection structure according to the embodiment of the present invention. FIGS. 5A and 5B are diagrams for explaining a method for forming an anisotropic conductive material layer into a B-stage using a coating apparatus in a method for manufacturing a connection structure according to an embodiment of the present invention. It is a schematic diagram. 6A and 6B are a plan view and a cross-sectional view showing a modification of the flexible printed circuit board. FIGS. 7A to 7D are schematic diagrams for explaining a modification of the movement direction of the dispenser.

  Details of the present invention will be described below.

  The method for manufacturing a connection structure according to the present invention uses a flexible printed circuit board (first connection target member) having a first electrode on the surface, and is curable on the first electrode of the flexible printed circuit board. Using the anisotropic conductive paste containing an ingredient and conductive particles, and using the second connection target member having the second electrode on the surface, the first connection A step of laminating the flexible printed circuit board and the second connection target member via the anisotropic conductive material layer with the electrode facing the second electrode, and the anisotropic conductive material layer And a step of forming a cured product layer.

  In the manufacturing method of the connection structure according to the present invention, in the step of disposing the anisotropic conductive material layer, the anisotropic conductive paste is applied from the dispenser while moving the dispenser on the first electrode. . Further, in at least one of the application start area A1 and the application end area A2, the application area B between the application start area A1 and the application end area A2 is greater than the application area B. A large amount of the anisotropic conductive paste is applied.

  By adopting the above configuration in the method for manufacturing a connection structure according to the present invention, it is possible to increase the abundance of the cured product layer in a relatively large amount of anisotropic conductive paste applied. For this reason, the connection reliability of a flexible printed circuit board and a 2nd connection object member can be improved. In particular, the portion where the peeling tends to occur relatively easily is the region A1 of the application start portion or the region A2 of the application end portion where a large amount of the anisotropic conductive paste is applied. Connection reliability with a connection object member can be improved effectively.

  Further, by applying the anisotropic conductive paste from the dispenser, it is easy to dispose the anisotropic conductive material layer in a predetermined region, and the manufacturing efficiency of the connection structure can be increased. Furthermore, in application | coating by a dispenser, the hardened | cured material layer in the connection structure obtained can be arrange | positioned accurately and uniformly to a specific area | region. As a result, voids are less likely to occur in the resulting connection structure, and the connection reliability and conduction reliability between the flexible printed circuit board and the second connection target member are increased. In addition, when the target to which the anisotropic conductive paste is applied is a flexible printed board, the flexible printed board often has a higher electrode height than the glass substrate. Is difficult to apply accurately and uniformly. By applying the anisotropic conductive paste with a dispenser, the anisotropic conductive paste can be applied accurately and uniformly.

  In addition, since the flexible printed circuit board is relatively soft, the anisotropic conductive material layer spreads out when the flexible printed circuit board is bonded to the second connection target member, and the conductive particles are likely to be disposed in an unintended region. There is. On the other hand, in the manufacturing method of the connection structure according to the present invention, the arrangement accuracy of the conductive particles can be sufficiently increased even though the flexible printed board is used.

  From the viewpoint of further improving the connection reliability between the flexible printed circuit board and the second connection target member, the application start part area A1 in both the application start part area A1 and the application end part area A2. It is preferable to apply a larger amount of the anisotropic conductive paste than the application region B between the region A2 and the region A2 where the application is completed.

  It is preferable to change the movement direction of the dispenser in at least one of the application area A1 and the application end area A2, and the anisotropic conductive paste is applied more in the changed movement direction. It is preferable to do. When the discharge speed of the anisotropic conductive paste from the dispenser is constant, the application amount of the anisotropic conductive paste in the application start portion area A1 or the application end portion area A2 is changed by changing the movement direction of the dispenser. Can be more.

  When the amount of application of the anisotropic conductive paste is increased by changing the movement direction of the dispenser, the movement direction of the dispenser may be changed in two straight lines at a predetermined angle or may be changed in a curved line shape. . Moreover, you may change the moving direction of a dispenser into a random direction. Further, the moving direction of the dispenser may be changed to a zigzag shape.

  It is preferable that the movement direction of the dispenser is changed by more than 0 degrees and 180 degrees or less in at least one of the application start area A1 and the application end area A2. It is preferable to apply a large amount of the anisotropic conductive paste.

  More preferably, the movement direction of the dispenser is changed by 30 degrees or more in at least one of the application start area A1 and the application end area A2. In this case, it is possible to easily increase the application amount in the area A1 of the application start portion or the area A2 of the application end portion, and to suppress the protrusion of the applied anisotropic conductive paste. Furthermore, it becomes difficult to arrange | position the hardened | cured material layer which the anisotropic conductive paste hardened | cured in the area | region which is not intended, and contamination by the hardened | cured material layer which this anisotropic conductive paste hardened can be suppressed.

  It is preferable to change the movement direction of the dispenser by more than 90 degrees, and more preferably by 120 degrees or more, in at least one of the application start area A1 and the application end area A2. In this case, the application amount of the end portion (folding tip) in the area A1 of the application start portion or the area A2 of the application end portion is reduced. For this reason, it is hard to arrange | position further the hardened | cured material layer which the anisotropic conductive paste hardened | cured by the area | region which is not intended, and it can suppress further the contamination by the hardened | cured material layer which this anisotropic conductive paste hardened | cured.

  It is preferable that the moving direction of the dispenser is changed by 160 degrees or less in at least one of the application start area A1 and the application end area A2. In this case, it is possible to suppress an increase in the coating thickness in the area A1 of the application start portion or the area A2 of the application end portion where the application amount is relatively large. As a result, the cured product layer in which the anisotropic conductive material is cured is more difficult to be disposed in an unintended region, and contamination by the cured product layer in which the anisotropic conductive material is cured can be further suppressed.

  The movement direction of the dispenser is preferably changed to a V-shape or U-shape in at least one of the application start area A1 and the application end area A2. It is preferable to apply a large amount of the anisotropic conductive paste. In this case, it is easy to control the application amount in the area A1 of the application start portion or the area A2 of the application end portion.

  One edge of the cured product layer is formed by the anisotropic conductive paste applied at the start of application, and the other edge of the cured product layer is applied at the end of application. It is preferable to form by. At least one of the one edge and the other edge of the cured product layer is more than the central portion of the cured product layer between the one edge and the other edge of the cured product layer. It is preferable to increase the abundance of the cured product layer. The edge part of the said hardened | cured material layer and the other edge part tend to become a peeling start point of a flexible printed circuit board and a 2nd connection object member. On the other hand, peeling can be effectively suppressed by increasing the abundance of the cured product layer in at least one of the one edge and the other edge of the cured product layer, and the connection in the connection structure Reliability can be further increased.

  Moreover, it is preferable to move the dispenser on the first electrode from one edge side to the other edge side of the first electrode.

  It is preferable that at least a part of the region of the cured product layer protrudes from at least one of the lateral side of the outer peripheral side surface of the flexible printed board and the lateral side of the outer peripheral side surface of the second connection target member. . It is preferable that at least a part of the region of the cured product layer protrudes both on the side of the outer peripheral side surface of the flexible printed board and on the side of the outer peripheral side surface of the second connection target member. A fillet of the cured product layer is formed in at least a part of the outer peripheral side surface of at least one of the outer side surface of the flexible printed circuit board and the side of the outer peripheral side surface of the second connection target member. Is preferably formed. A fillet of the cured product layer is formed in at least a part of the outer peripheral side surface both on the side of the outer peripheral side surface of the flexible printed board and on the side of the outer peripheral side surface of the second connection target member. It is more preferable. Thus, when a hardened | cured material layer is protruded and a fillet is formed, peeling can be suppressed effectively and the connection reliability in a connection structure can be improved further.

  It is preferable to form a fillet of the cured product layer on at least one of the one edge and the other edge of the cured product layer, and both the one edge and the other edge of the cured product layer are formed. Thus, it is more preferable to form a fillet of the cured product layer. Since peeling can be effectively suppressed at one edge and the other edge of the cured product layer that is likely to become a separation starting point, connection reliability in the connection structure can be further enhanced.

  From the viewpoint of further improving the connection reliability between the flexible printed circuit board and the second connection target member, one edge and the other edge of the cured product layer, and one edge and the other of the cured product layer It is more preferable to form a fillet of the cured product layer at the central portion between the edges of the cured product layer.

  From the viewpoint of further enhancing the connection reliability between the flexible printed circuit board and the second connection target member, the flexible printed circuit board or the second printed circuit board of the fillet at one edge and the other edge of the cured product layer. The protruding distance from the outer peripheral side surface of the member to be connected is set so that the fillet of the fillet at the center of the cured product layer between one edge and the other edge of the cured product layer or the second It is preferable to make it larger than the protruding distance from the outer peripheral side surface of the connection target member.

  It is preferable that the flexible printed circuit board has a protruding first electronic electrode on the surface and a protruding electronic component having a higher protruding height than the first electrode on the surface. When such a flexible printed circuit board is used, it is difficult to dispose the anisotropic conductive paste on the flexible printed circuit board by screen printing. On the other hand, when the anisotropic conductive paste is applied onto the flexible printed board using a dispenser, the anisotropic conductive paste easily flows, and the anisotropic conductive material layer and the conductive particles are present in unintended areas. There is a problem that it is easy to arrange. On the other hand, in the manufacturing method of the connection structure according to the present invention, the protruding electronic component having the protruding first electrode on the surface and having a protruding height larger than the first electrode is provided on the surface. Even if the flexible printed circuit board is used, the arrangement accuracy of the conductive particles can be increased. In application by a dispenser, even if the flexible printed circuit board has an electronic component protruding on the surface, since the inhibition of the application operation by the electronic component can be suppressed, the application efficiency of the anisotropic conductive paste can be considerably increased.

  The first electrode may be a plurality of first electrodes or a first electrode pattern. In this case, the second electrode may be a plurality of second electrodes or a second electrode pattern. In this case, it is preferable to dispose the anisotropic conductive material layer not on the plurality of first electrodes but also on the gaps between the plurality of first electrodes. It is preferable that the anisotropic conductive material layer is disposed by continuously applying the anisotropic conductive paste on the plurality of first electrodes and on the gaps between the plurality of first electrodes.

  It is preferable that the gap between the plurality of first electrodes of the flexible printed circuit board does not protrude or the height of protrusion is smaller than that of the first electrode, and does not protrude between the first electrodes of the flexible printed circuit board. preferable. In this case, the surface of the flexible printed circuit board is uneven on the plurality of first electrodes and on the gaps between the plurality of first electrodes. It is preferable to dispose the anisotropic conductive material layer also in a region where the surface of the flexible printed board does not protrude or a region where the degree of protrusion is smaller than that of the first electrode.

  The thickness of the anisotropic conductive material layer portion disposed on the plurality of first electrodes is made thinner than the thickness of the anisotropic conductive material layer portion disposed on the gap between the plurality of first electrodes. Is preferred. In this case, unevenness on the upper surface of the anisotropic conductive material layer disposed on the plurality of first electrodes and on the gaps between the plurality of first electrodes can be reduced. As a result, voids are less likely to occur in the connection structure, and connection reliability can be improved.

  The upper surface of the anisotropic conductive material layer portion disposed on the plurality of first electrodes and the upper surface of the anisotropic conductive material layer portion disposed between the plurality of first electrodes are smoothed so as to be continuous. It is preferable. In this case, in the connection structure, voids can be made more difficult to occur, and connection reliability can be further improved.

  When the flexible printed circuit board has a plurality of first electrodes on the surface, the height of the first electrodes is 30 μm or more, and the gap between the plurality of first electrodes is 30 μm or less. Preferably there is. When an anisotropic conductive material layer is arranged on the surface of a flexible printed board having such a first electrode, it is quite difficult to arrange the anisotropic conductive material layer accurately and uniformly in screen printing. It is. On the other hand, the anisotropic conductive material layer can be accurately and uniformly disposed by applying the anisotropic conductive paste from the dispenser while moving the dispenser. Moreover, it is preferable that the 2nd electrode of the 2nd connection object member is arrange | positioned in the position corresponding to the 1st electrode of a flexible printed circuit board. It is preferable that the space | interval of the clearance gap (space) between several 2nd electrodes is 30 micrometers or less.

  The anisotropic conductive paste has a viscosity η1 at 25 ° C. and 2.5 rpm of more than 200 Pa · s and preferably 800 Pa · s or less. The viscosity η1 is more preferably 300 Pa · s or more, and more preferably 500 Pa · s or less. When the viscosity η1 is not less than the above lower limit and not more than the above upper limit, in the connection structure using the flexible printed circuit board, voids are further hardly generated and connection reliability can be further improved.

  The viscosity ratio (η2 / η3) of the anisotropic conductive paste to the viscosity η3 at 25 ° C. and 5 rpm of the viscosity η2 at 25 ° C. and 2.5 rpm is preferably 1 or more and 4 or less. The viscosity ratio (η2 / η3) is more preferably 1.1 or more, and more preferably 3.5 or less. When the viscosity ratio (η2 / η3) is not less than the above lower limit and not more than the above upper limit, in the connection structure using the flexible printed circuit board, voids are further less likely to be generated, and connection reliability is further improved. it can.

  The flexible printed circuit board has a plurality of first electrodes on the surface, the second connection target member has a plurality of second electrodes on the surface, and the height of the first electrode is 5 μm or more. The gap between the first electrodes is 30 μm or less, the viscosity η1 is more than 200 Pa · s and not more than 800 Pa · s, and the viscosity ratio (η2 / η3) is 1 or more and 4 or less. It is particularly preferred. In particular, when the interval between the plurality of first electrodes is narrow, it is very difficult to accurately and uniformly dispose the anisotropic conductive material layer in the narrow gap region between the plurality of first electrodes. . On the other hand, while moving the dispenser, by applying an anisotropic conductive paste having the viscosity η1 and the viscosity ratio (η2 / η3) that are equal to or higher than the lower limit and equal to or lower than the upper limit, the narrowness is achieved. The anisotropic conductive material layer can be accurately and evenly disposed in the gap region. For this reason, in a connection structure, it becomes difficult to produce a void still more effectively and can improve connection reliability still more effectively.

  It is preferable that the thickness of the anisotropic conductive material layer portion disposed on the first electrode is at least three times the average particle diameter of the conductive particles contained in the anisotropic conductive paste. In this case, in the connection structure, voids can be made more difficult to occur, and connection reliability can be further improved. More preferably, the thickness of the anisotropic conductive material layer portion disposed on the first electrode is at least four times the average particle diameter of the conductive particles contained in the anisotropic conductive paste. It is preferable to make it less than twice. In this case, generation of voids in the connection structure can be further suppressed.

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

  1A to 1C schematically show a connection structure obtained by the method for manufacturing a connection structure according to one embodiment of the present invention in a partially cutaway cross-sectional view. 2A and 2B schematically show a flexible printed board used in the method for manufacturing a connection structure according to one embodiment of the present invention in a plan view and a cross-sectional view.

  Fig.1 (a) is sectional drawing in area | region A1 of the application | coating start part. FIG. 1B is a cross-sectional view of the application region B between the application start portion region A1 and the application end portion region A2. FIG.1 (c) is sectional drawing in area | region A2 of the application completion part. In FIG. 1A, a cross-sectional view in a state in which a second connection target member is connected to the flexible printed board is shown along line II in the flexible printed board shown in FIG. Yes. In FIG.1 (b), sectional drawing in the state in which the 2nd connection object member is connected to this flexible printed circuit board is shown along the II-II line in the flexible printed circuit board shown to Fig.2 (a). Yes. In FIG.1 (c), sectional drawing in the state in which the 2nd connection object member is connected to this flexible printed circuit board is shown along the III-III line in the flexible printed circuit board shown to Fig.2 (a). Yes. FIG. 2B shows a cross-sectional view taken along the line IV-IV shown in FIG.

  A connection structure 1 shown in FIG. 1 includes a flexible printed circuit board 4, a second connection target member 2, and a cured product layer 3. The cured product layer 3 connects the flexible printed circuit board 4 and the second connection target member 2 and is a connection part. The cured product layer 3 is formed by curing an anisotropic conductive material including a curable component and the conductive particles 5. The anisotropic conductive material includes a plurality of conductive particles 5.

  The 2nd connection object member 2 has the 2nd electrode 2b in the surface 2a (lower surface). The second electrode 2b protrudes from the surface 2a. The second electrode 2b as a whole has a length direction and a width direction. 1A to 1C show a cross section in the width direction of the entire second electrode 2b.

  The flexible printed circuit board 4 has a first electrode 4b on the surface (upper surface) 4a. The first electrode 4b protrudes from the surface 4a. The first electrode 4b as a whole has a length direction and a width direction. 1A to 1C show a cross section in the width direction of the entire first electrode 4b.

  The second electrode 2b and the first electrode 4b are electrically connected by one or a plurality of conductive particles 5.

  In the connection structure 1, a glass substrate is used as the second connection target member 2. The second connection target member is not particularly limited. Specific examples of the second connection target member include electronic components such as a semiconductor chip, a capacitor, and a diode, and electronic components such as a circuit board such as a printed board, a flexible printed board, and a glass board. The second connection object member is preferably a glass substrate.

  In the connection structure 1, one edge part of the hardened | cured material layer 3 is formed with the anisotropic electrically conductive paste apply | coated at the time of an application | coating start. The other edge part of the hardened | cured material layer 3 is formed with the said anisotropic conductive paste apply | coated at the time of completion | finish of application | coating. One edge of the cured product layer 3 is disposed on one edge of the first and second electrodes 4b and 2b. The other edge part of the hardened | cured material layer 3 is arrange | positioned at the other edge part side of the 1st, 2nd electrodes 4b and 2b.

  Further, as shown in FIGS. 1A to 1C, fillets F made of the cured product layer 3 are formed on the side of the outer peripheral side surface of the flexible printed circuit board 4. A fillet F made of the cured product layer 3 is formed on the side of the outer peripheral side surface of the second connection target member 2. However, the fillet by the said hardened | cured material layer may be formed only in one of the side from the outer peripheral side surface of the flexible printed circuit board and the outer peripheral side surface of the said 2nd connection object member.

  As shown in FIGS. 1 (a) to 1 (c), one edge and the other edge of the cured product layer 3 and a central portion between the one edge and the other edge of the cured product layer 3. And the fillet F by the hardened | cured material layer 3 is formed. The fillet F of the cured product layer 3 protrudes from the outer peripheral side surface of the first connection target member 4 or the second connection target member 2. The protrusion distance D from the outer peripheral side surface of the flexible printed circuit board 4 or the second connection target member 2 of the fillet F at one edge and the other edge of the cured product layer 3 is equal to one edge of the cured product layer 3. It is larger than the protruding distance D from the outer peripheral side surface of the flexible printed circuit board 4 or the second connection target member 2 of the fillet F in the central portion of the cured product layer 3 between the other edge portion.

  As shown in FIGS. 2A and 2B, the flexible printed circuit board 4 has an electronic component 4c on the surface 4a. The electronic component 4c is disposed on the same surface 4a as the side on which the first electrode 4b is disposed. The first electrode 4b and the electronic component 4c provided on the flexible printed board 4 protrude on the same surface 4a. The flexible printed circuit board 4 is connected to the second connection target member 2 in an area where the electronic component 4c is not provided.

  On the surface 4a, the protruding height Hc of the electronic component 4c is preferably larger than the protruding height Hb of the first electrode 4b. The protruding height Hc of the electronic component 4c is preferably 10 μm or more, more preferably 15 μm or more, preferably 50 μm or less, more preferably 30 μm or less. It is preferable that the protrusion height Hc of the electronic component 4c exceeds one time the protrusion height Hb of the first electrode 4b. The projecting height Hc of the electronic component 4c is more preferably 10 times or more of the projecting height Hb of the first electrode 4b, more preferably 20 times or more, and preferably 200 times or less, More preferably, it is 100 times or less. Even if the protrusion height Hc is larger than the protrusion height Hb, the anisotropic conductive material layer can be efficiently and accurately applied by applying the anisotropic conductive paste from the dispenser while moving the dispenser. Can be placed.

  Examples of the electronic component 4c include a semiconductor chip and a connector. The electronic component 4c is preferably a semiconductor chip.

  6A and 6B, as shown in a plan view and a cross-sectional view, a plurality of first electrodes 61b (first electrode patterns) are replaced with a surface 61a in place of the first connection target member 4. A flexible printed circuit board 61 having a protruding electronic component 61c on the surface 61a that has a protruding height larger than that of the first electrode 61b may be used.

  The connection structure 1 can be obtained as follows. Here, the manufacturing method of the connection structure 1 when the anisotropic conductive paste containing a photocurable component, a thermosetting component, and the conductive particles 5 is used as the anisotropic conductive paste is specifically described. explain. That is, a method of manufacturing the connection structure 1 using an anisotropic conductive paste that can be cured by light irradiation and heat application will be described.

  First, the flexible printed circuit board 4 shown in FIGS. 2A and 2B is prepared. That is, the flexible printed circuit board 4 is prepared which has the protruding first electrode 4b on the surface 4a and the protruding electronic component 4c having a protruding height larger than that of the first electrode 4b on the surface 4a. The flexible printed circuit board 4 is arranged such that the surface 4a on the side where the first electrode 4b and the electronic component 4c are provided is on the upper side.

  FIG. 3A1 is a cross-sectional view in the area A1 of the application start portion. 3A2, 3B, and 3C are cross-sectional views in the application region B between the application start portion area A1 and the application end portion area A2. FIG. 3A3 is a cross-sectional view in the region A2 of the application end portion.

  FIG. 3A1 shows a cross-sectional view of the flexible printed board with an anisotropic conductive paste applied along the line II in the flexible printed board shown in FIG. FIG. 3A2 shows a cross-sectional view in a state where an anisotropic conductive paste is applied to the flexible printed board along the line II-II in the flexible printed board shown in FIG. FIG. 3A3 shows a cross-sectional view in the state in which the anisotropic conductive paste is applied to the flexible printed board along the line III-III in the flexible printed board shown in FIG.

  As shown in FIGS. 3 (a1) to (a3), on the surface 4a of the flexible printed board 4, an anisotropic conductive paste containing a photocurable component, a thermosetting component, and conductive particles 5 is used. An anisotropic conductive paste is applied to dispose the anisotropic conductive material layer 3 </ b> A on the surface 4 a of the flexible printed circuit board 4. An anisotropic conductive material layer 3A is disposed on the first electrode 4b. It is preferable that one or a plurality of conductive particles 5 are arranged on the first electrode 4b. The application amount of the anisotropic conductive paste in the region A1 (FIG. 3 (a1)) of the application start portion and the region A2 (FIG. 3 (a3)) of the application end portion is the application region B (FIG. 3 (a2)). More than the application amount of the anisotropic conductive paste in.

  By moving the dispenser at a position indicated by a straight line X in FIGS. 2A and 4 and applying the anisotropic conductive paste to the surface 4a of the flexible printed circuit board 4, FIGS. The state shown in (a2) and FIG. 3 (a3) can be obtained. Specifically, as shown in FIG. 4, the dispenser is moved from point x1 to point x2, then the dispenser is moved from point x2 to point x3, and then the dispenser is moved from point x3 to point x4. The part from the point x1 to the point x2 and the first part from the point x2 to the point x3 correspond to the area A1 of the application start part, and the final part from the point x2 to the point x3 and the part from the point x3 to the point x4 Corresponds to the region A2 of the application end portion. Further, a portion excluding the first portion and the final portion from the point x2 to the point x3 corresponds to the application region B. Here, the movement direction of the dispenser is changed to a V shape by 150 degrees in both the application area of the application start area A1 and the application end area A2.

  As shown to Fig.7 (a)-(d), the moving direction of the said dispenser can be changed suitably. In FIG. 7A, the movement direction of the dispenser is changed by 90 degrees. In FIG. 7B, the movement direction of the dispenser is changed to a U shape by 180 degrees. In FIG. 7C, the movement direction of the dispenser is changed in a zigzag manner by 70 degrees.

  2A and 4, the first electrode 4b is in a state where the position of the dispenser is shifted to the edge side from the center of the first electrode 4b in the direction orthogonal to the movement direction of the dispenser. The anisotropic conductive paste is applied from the dispenser while moving the dispenser.

  As shown in FIG. 7 (d), while the dispenser is moved on the first electrode 4b along the central portion of the first electrode 4b in the direction orthogonal to the movement direction of the dispenser, the anisotropic conduction is performed. The paste may be applied from the dispenser.

  In the length direction of the first electrode 4b, the dispenser is moved on the first electrode 4b from the one edge side to the other edge side of the first electrode 4b. Therefore, the region A1 of the application start portion is located on one edge side of the first electrode 4b, and the region A2 of the application end portion is located on the other edge side of the first electrode 4b. In addition, the application region B is located between one edge and the other edge of the first electrode 4b.

  In addition, the anisotropic conductive paste is applied in a region surrounded by a broken line Y in FIGS. Note that, when the flexible printed circuit board 4 and the second connection target member 2 are connected, the anisotropic conductive material layer or the B-staged anisotropic conductive material layer extends beyond the region surrounded by the broken line Y.

  Next, the anisotropic conductive material layer 3A is cured by irradiating the anisotropic conductive material layer 3A with light. By curing the anisotropic conductive material layer 3A, the anisotropic conductive material layer 3A is B-staged. By forming the anisotropic conductive material layer 3A into a B-stage, the B-staged anisotropic conductive material layer 3B is formed on the surface 4a of the flexible printed circuit board 4 as shown in FIG. 3B.

  5A and 5B are side views showing a state when the anisotropic conductive material layer is arranged. In FIGS. 5A and 5B, illustration of the first electrode 4b and the electronic component 4c is omitted. In order to form the anisotropic conductive material layer 3A, a coating apparatus 11 shown in FIG. 5A is preferably used. In FIG. 5A, the moving direction of the dispenser 12 and the application direction of the anisotropic conductive paste are directions from the right side to the left side.

  The coating device 11 is used to apply an anisotropic conductive paste containing a curable component and conductive particles 5 to the surface 4 a of the flexible printed circuit board 4. The coating device 11 includes a dispenser 12 and a light irradiation device 13 connected to the dispenser 12. The dispenser 12 includes a syringe 12a for filling the inside with an anisotropic conductive paste, and a grip portion 12b that grips the outer peripheral surface of the syringe 12a. The light irradiation device 13 includes a light irradiation device main body 13a and a light irradiation unit 13b.

  The dispenser 12 is a dispenser for applying the anisotropic conductive paste to the surface 4 a of the flexible printed board 4. The light irradiation device 13 is a light irradiation device for applying the anisotropic conductive paste to the surface 4a of the flexible printed circuit board 4 and irradiating the anisotropic conductive paste with light.

  As shown in FIG. 5A, when applying the anisotropic conductive paste, the syringe 12a of the dispenser 12 is placed on the surface 4a of the flexible printed circuit board 4 while moving the coating device 11 in the direction of arrow A. An anisotropic conductive paste is applied from the tip 12c to form the anisotropic conductive material layer 3A.

  As shown in FIG. 5B, when irradiating light, light is irradiated to the anisotropic conductive material layer 3A from the light irradiation unit 13b of the light irradiation device 13 connected to the dispenser 12 as indicated by an arrow B. Irradiate. Here, while applying the anisotropic conductive paste, the anisotropic conductive material layer 3A is irradiated with light from the light irradiation unit 13b of the light irradiation device 13 connected to the dispenser 12 as indicated by an arrow B. Yes.

  It is preferable to irradiate the anisotropic conductive material layer 3 </ b> A with light while applying the anisotropic conductive paste to the surface 4 a of the flexible printed circuit board 4. Furthermore, it is also preferable to irradiate the anisotropic conductive material layer 3 </ b> A with light immediately after the application of the anisotropic conductive paste to the surface 4 a of the flexible printed board 4 or immediately after the application. When the application and the light irradiation are performed as described above, the flow of the anisotropic conductive material layer 3A or the B-staged anisotropic conductive material layer 3B can be further suppressed. For this reason, the connection reliability between the flexible printed circuit board 4 and the connection target member 2 and the conduction reliability between the first and second electrodes 4b and 2b are further enhanced. From the viewpoint of controlling the time until light irradiation with high accuracy, it is preferable to move the dispenser 12 and the light irradiation device 13, and it is preferable to move the dispenser 12 and the light irradiation device 13 in conjunction with each other. 12 and the light irradiation device 13 are preferably moved at the same speed. As described above, it is preferable to apply the anisotropic conductive paste while moving the dispenser 12 and the light irradiation device 13 to irradiate the anisotropic conductive material layer 3A with light. The time from the application of the anisotropic conductive paste to the surface 4a of the flexible printed board 4 to the irradiation with light is 0 second or more, preferably 3 seconds or less, more preferably 2 seconds or less. However, the table 31 may be moved in the direction opposite to the arrow A without moving the coating apparatus 11.

  In the coating device 11, the dispenser 12 and the light irradiation device 13 are connected by connecting the grip portion 12b and the light irradiation device main body 13a. Accordingly, the dispenser 12 and the light irradiation device 13 can be moved in conjunction with each other, and the dispenser 12 and the light irradiation device 13 can be moved at the same speed. Furthermore, the distance between the dispenser 12 and the light irradiation device 13 can be reduced, that is, the distance between the discharge part of the dispenser 12 and the light irradiation part 13b can be reduced. As a result, the anisotropic conductive material layer 3A applied by the dispenser 12 can be quickly irradiated with light. In addition, the syringe 12a and the light irradiation apparatus main body 13a may be directly connected.

  In order to irradiate light to the anisotropic conductive material layer 3 </ b> A, a dispenser 12 and a light irradiation device that is not connected to the dispenser 12 may be used. When using the dispenser 12 and the light irradiation device that is not connected to the dispenser 12, for example, the light irradiation device is disposed above the flexible printed circuit board 4. Next, the anisotropic conductive paste is applied from the syringe 12a to the surface 4a of the flexible printed circuit board 4 while moving the dispenser 12 in the direction of arrow A between the flexible printed circuit board 4 and the light irradiation device. The isotropic conductive material layer 3A is formed. Next, after the application of the anisotropic conductive paste is completed, the anisotropic conductive material layer 3 </ b> A is irradiated with light from the light irradiation unit of the light irradiation device disposed above the flexible printed circuit board 4. The light irradiation is performed, for example, simultaneously with the application of the anisotropic conductive paste or immediately after the application.

The light irradiation intensity for causing the anisotropic conductive material layer 3A to be B-staged by light irradiation and allowing the curing to proceed appropriately is, for example, preferably about 0.1 to 10,000 mW / cm ² . Moreover, the light irradiation energy for advancing moderately curing the anisotropic conductive material layer 3A is preferably 50 mJ / cm ² or more, more preferably 100 mJ / cm ² or more, preferably 100000mJ / cm ² or less, more Preferably it is 50000 mJ / cm ² or less.

  The light source used when irradiating light is not specifically limited. Examples of the light source include a light source having a sufficient light emission distribution at a wavelength of 420 nm or less. Specific examples of the light source include, for example, a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a chemical lamp, a black light lamp, a microwave excitation mercury lamp, a metal halide lamp, and an LED lamp.

  Note that the anisotropic conductive material layer 3A may be B-staged by applying heat without the anisotropic conductive material layer 3A being B-staged by light irradiation. When the anisotropic conductive material layer 3A is B-staged by applying heat to the anisotropic conductive material layer 3A to cure the anisotropic conductive material layer 3A, the anisotropic conductive material layer 3A is appropriately B-staged. The heating temperature for this is preferably 80 ° C or higher, preferably 150 ° C or lower, more preferably 120 ° C or lower. Even when the anisotropic conductive material layer 3A is B-staged by applying heat instead of irradiating with light, as long as the anisotropic conductive paste is applied from the dispenser 12 as described above, the first and second The positional deviation between the electrodes 4b and 2b can be suppressed.

  Next, as shown in FIG. 3C, the second connection target member 2 is laminated on the upper surface 3a of the B-staged anisotropic conductive material layer 3B. The second connection target member 2 is laminated so that the first electrode 4b on the surface 4a of the flexible printed circuit board 4 and the second electrode 2b on the surface 2a of the second connection target member 2 face each other. In addition, after lamination | stacking of the 2nd connection object member 2, in order to make anisotropic conductive material layer 3A into B stage, you may irradiate light and may provide heat. However, after the second connection target member 2 is stacked, it is preferable to apply heat or irradiate light in order to make the anisotropic conductive material layer 3A into a B-stage.

  Further, when the second connection target member 2 is laminated, the B-staged anisotropic conductive material layer 3B is heated and fully cured to form the cured product layer 3. However, the anisotropic conductive material layer 3B may be heated before the second connection target member 2 is laminated. However, it is preferable that the anisotropic conductive material layer 3B is heated and fully cured after the second connection target member 2 is laminated.

  In order to cure the anisotropic conductive material layer 3B by applying heat, the heating temperature for sufficiently curing the anisotropic conductive material layer 3B is preferably 160 ° C or higher, preferably 250 ° C or lower, more preferably 200. It is below ℃.

  When the anisotropic conductive material layer 3A is not B-staged without applying heat or irradiating light to the anisotropic conductive material layer 3A, the second surface is formed on the upper surface 3a of the anisotropic conductive material layer 3A. The connection target member 2 may be laminated, and the anisotropic conductive material layer 3A may be heated to be fully cured.

  It is preferable to apply pressure when the anisotropic conductive material layer 3B is cured. By compressing the conductive particles 5 with the first electrode 4b and the second electrode 2b by pressurization, the contact area between the first and second electrodes 4b, 2b and the conductive particles 5 can be increased. it can. For this reason, conduction reliability can be improved.

  By curing the anisotropic conductive material layer 3 </ b> B, the flexible printed circuit board 4 and the second connection target member 2 are connected via the cured product layer 3. In addition, the first electrode 4 b and the second electrode 2 b are electrically connected through the conductive particles 5. In this way, the connection structure 1 shown in FIG. 1 can be obtained. In this embodiment, since photocuring and thermosetting are used together, the anisotropic conductive paste can be cured in a short time.

  In addition, when the connection structure is produced, the anisotropic conductive paste is made into a B-stage by applying heat or irradiating light, and then cured to form an anisotropic paste layer disposed on the flexible printed circuit board. The contained conductive particles are difficult to flow greatly in the curing stage. Accordingly, the conductive particles are easily arranged in a predetermined region. Specifically, conductive particles can be arranged between upper and lower electrodes to be connected, and adjacent electrodes that should not be connected are electrically connected via a plurality of conductive particles. Can be suppressed. For this reason, the conduction | electrical_connection reliability between the electrodes in a connection structure can be improved.

  In addition, when the anisotropic conductive paste is made into a B stage by applying heat or irradiating light during the production of the connection structure, the influence of the surface shape of the anisotropic conductive material layer before the B stage is made. Therefore, the first and second electrodes tend to be misaligned. For example, in a B-staged anisotropic conductive material layer, the viscosity has increased to some extent as a result of B-stage formation. For example, a large convex or concave portion is formed on the upper surface of the B-staged anisotropic conductive material layer. If it exists, in the connection structure obtained, there exists a tendency for the position shift between the electrodes in the 1st, 2nd connection object member to arise easily.

  On the other hand, even if the B-stage is achieved by reducing the unevenness of the upper surface 3a of the anisotropic conductive material layer 3A or smoothing it by eliminating the unevenness, the first and second connection target members The positional deviation between the electrodes can be effectively suppressed.

  In addition, when the anisotropic conductive paste is not B-staged by applying heat or irradiating light when the connection structure is produced, the viscosity of the anisotropic conductive material layer before B-stage is too low. In the obtained connection structure, there is a tendency that positional displacement between the first and second electrodes is likely to occur. On the other hand, when the connection structure is produced, the anisotropic conductive paste is made into a B-stage by applying heat or irradiating light, so that the positional deviation between the electrodes in the first and second connection target members is reduced. It can be effectively suppressed.

  The anisotropic conductive paste includes a curable component and conductive particles. The curable component preferably includes a thermosetting component. The curable component may contain a photocurable component. The thermosetting component preferably contains a thermosetting compound and a thermosetting agent. The anisotropic conductive paste preferably further includes a photocurable component in addition to the thermosetting component. The photocurable component preferably contains a photocurable compound and a photocuring initiator. The anisotropic conductive paste preferably contains a thermosetting compound as a curable compound and further contains a photocurable compound. The thermosetting compound is preferably a compound having an epoxy group or a thiirane group. The photocurable compound is preferably a compound having a (meth) acryloyl group.

  Hereinafter, each component contained in the anisotropic conductive paste and details of each component preferably contained will be described.

[Thermosetting compound]
The thermosetting compound has thermosetting properties. As for the said thermosetting compound, only 1 type may be used and 2 or more types may be used together.

  Examples of the thermosetting compound include oxetane compounds, epoxy compounds, episulfide compounds, (meth) acrylic compounds, phenolic compounds, amino compounds, unsaturated polyester compounds, polyurethane compounds, silicone compounds, and polyimide compounds. As for the said thermosetting compound, only 1 type may be used and 2 or more types may be used together.

  From the viewpoint of easily controlling the curing of the anisotropic conductive paste or further improving the conduction reliability in the connection structure, the thermosetting compound is a thermosetting compound having an epoxy group or a thiirane group. It is preferable that a thermosetting compound having a thiirane group is included. The thermosetting compound having an epoxy group is an epoxy compound. The thermosetting compound having a thiirane group is an episulfide compound. From the viewpoint of enhancing the curability of the anisotropic conductive paste, the content of the compound having an epoxy group or thiirane group is preferably 10% by weight or more, more preferably 20% by weight in 100% by weight of the thermosetting compound. % Or more and 100% by weight or less. The total amount of the thermosetting compound may be a compound having the epoxy group or thiirane group.

  Since the episulfide compound has a thiirane group instead of an epoxy group, it can be quickly cured at a low temperature. That is, the episulfide compound having a thiirane group can be cured at a lower temperature derived from the thiirane group as compared with the epoxy compound having an epoxy group.

  The thermosetting compound having an epoxy group or thiirane group preferably has an aromatic ring. Examples of the aromatic ring include a benzene ring, naphthalene ring, anthracene ring, phenanthrene ring, tetracene ring, chrysene ring, triphenylene ring, tetraphen ring, pyrene ring, pentacene ring, picene ring, and perylene ring. Especially, it is preferable that the said aromatic ring is a benzene ring, a naphthalene ring, or an anthracene ring, and it is more preferable that it is a benzene ring or a naphthalene ring. A naphthalene ring is preferred because it has a planar structure and can be cured more rapidly.

[Photocurable compound]
The anisotropic conductive paste preferably contains a photocurable compound so as to be cured by irradiation with light. The photocurable compound can be semi-cured (B-staged) by irradiation with light to reduce the fluidity of the anisotropic conductive paste.

  The photocurable compound is not particularly limited, and examples thereof include a photocurable compound having a (meth) acryloyl group and a photocurable compound having a cyclic ether group.

  The photocurable compound is preferably a photocurable compound having a (meth) acryloyl group. By using the photocurable compound having a (meth) acryloyl group, the conduction reliability of the connection structure can be further enhanced. From the viewpoint of effectively increasing the conduction reliability of the resulting connection structure, the photocurable compound preferably has one or two (meth) acryloyl groups.

  The photocurable compound having the (meth) acryloyl group has no epoxy group and thiirane group, and has a (meth) acryloyl group, and has an epoxy group or thiirane group, and ( The photocurable compound which has a (meth) acryloyl group is mentioned.

  As a photocurable compound having the above (meth) acryloyl group, an ester compound obtained by reacting a compound having (meth) acrylic acid and a hydroxyl group, an epoxy obtained by reacting (meth) acrylic acid and an epoxy compound. (Meth) acrylate or urethane (meth) acrylate obtained by reacting a (meth) acrylic acid derivative having a hydroxyl group with isocyanate is preferably used. The “(meth) acryloyl group” refers to an acryloyl group and a methacryloyl group. The “(meth) acryl” refers to acryl and methacryl. The “(meth) acrylate” refers to acrylate and methacrylate.

  The ester compound obtained by making the said (meth) acrylic acid and the compound which has a hydroxyl group react is not specifically limited. As the ester compound, any of a monofunctional ester compound, a bifunctional ester compound, and a trifunctional or higher functional ester compound can be used.

  The photocurable compound having the epoxy group or thiirane group and having a (meth) acryloyl group is a part of the epoxy group or part of thiirane of the compound having two or more epoxy groups or two or more thiirane groups. It is preferable that it is a photocurable compound obtained by converting a group into a (meth) acryloyl group. Such a photocurable compound is a partially (meth) acrylated epoxy compound or a partially (meth) acrylated episulfide compound.

  The photocurable compound is preferably a reaction product of a compound having two or more epoxy groups or two or more thiirane groups and (meth) acrylic acid. This reaction product is obtained by reacting a compound having two or more epoxy groups or two or more thiirane groups with (meth) acrylic acid in the presence of a basic catalyst according to a conventional method. It is preferable that 20% or more of the epoxy group or thiirane group is converted (converted) to a (meth) acryloyl group. The conversion is more preferably 30% or more, preferably 80% or less, more preferably 70% or less. Most preferably, 40% or more and 60% or less of the epoxy group or thiirane group is converted to a (meth) acryloyl group.

  Examples of the partially (meth) acrylated epoxy compound include bisphenol type epoxy (meth) acrylate, cresol novolac type epoxy (meth) acrylate, carboxylic acid anhydride-modified epoxy (meth) acrylate, and phenol novolac type epoxy (meth) acrylate. Is mentioned.

  As the photocurable compound, a modified phenoxy resin obtained by converting a part of epoxy groups or a part of thiirane groups of a phenoxy resin having two or more epoxy groups or two or more thiirane groups into (meth) acryloyl groups is used. Also good. That is, a modified phenoxy resin having an epoxy group or thiirane group and a (meth) acryloyl group may be used.

  Further, the photocurable compound may be a crosslinkable compound or a non-crosslinkable compound.

  Specific examples of the crosslinkable compound include 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, (poly ) Ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, pentaerythritol di (meth) acrylate, glycerol methacrylate acrylate, pentaerythritol tri (meth) acrylate, tri Examples include methylolpropane trimethacrylate, allyl (meth) acrylate, vinyl (meth) acrylate, divinylbenzene, polyester (meth) acrylate, and urethane (meth) acrylate.

  Specific examples of the non-crosslinkable compound include ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) ) Acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, nonyl (meth) acrylate, decyl (Meth) acrylate, undecyl (meth) acrylate, dodecyl (meth) acrylate, tridecyl (meth) acrylate, tetradecyl (meth) acrylate, and the like.

  When using a photocurable compound, the compounding ratio of a photocurable compound and a thermosetting compound is suitably adjusted according to the kind of a photocurable compound and a thermosetting compound. The anisotropic conductive paste preferably contains a photocurable compound and a thermosetting compound in a weight ratio of 1:99 to 90:10, more preferably 5:95 to 70:30, More preferably, it is included at 10:90 to 50:50. The anisotropic conductive paste particularly preferably contains a photocurable compound and a thermosetting compound in a weight ratio of 1:99 to 50:50.

(Thermosetting agent)
The anisotropic conductive paste preferably contains a thermosetting agent. The thermosetting agent includes a thermal radical initiator. As for a thermosetting agent, only 1 type may be used and 2 or more types may be used together.

  The said thermosetting agent is not specifically limited. Examples of the thermosetting agent include an imidazole thermosetting agent, an amine thermosetting agent, a phenol thermosetting agent, a polythiol thermosetting agent, an acid anhydride, and a thermal radical initiator. Especially, since an anisotropic electrically conductive paste can be hardened more rapidly at low temperature, an imidazole thermosetting agent, a polythiol thermosetting agent, or an amine thermosetting agent is preferable. Moreover, since the storage stability of anisotropic conductive paste can be improved, a latent thermosetting agent is preferable. The latent thermosetting agent is preferably a latent imidazole thermosetting agent, a latent polythiol thermosetting agent, or a latent amine thermosetting agent. In addition, the said thermosetting agent may be coat | covered with polymeric substances, such as a polyurethane resin or a polyester resin.

  The imidazole thermosetting agent is not particularly limited, but 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 -A triazine isocyanuric acid adduct etc. are mentioned.

  The polythiol thermosetting agent is not particularly limited, and examples thereof include trimethylolpropane tris-3-mercaptopropionate, pentaerythritol tetrakis-3-mercaptopropionate, and dipentaerythritol hexa-3-mercaptopropionate. It is done.

  Although it does not specifically limit as said amine thermosetting agent, Hexamethylene diamine, octamethylene diamine, decamethylene diamine, 3,9-bis (3-aminopropyl) 2,4,8,10-tetraspiro [5.5] Examples include undecane, bis (4-aminocyclohexyl) methane, metaphenylenediamine, and diaminodiphenylsulfone.

  The thermal radical initiator is not particularly limited, and examples thereof include azo compounds and peroxides. Examples of the peroxide include diacyl peroxide compounds, peroxyester compounds, hydroperoxide compounds, peroxydicarbonate compounds, peroxyketal compounds, dialkyl peroxide compounds, and ketone peroxide compounds.

  Examples of the azo compound include 2,2′-azobisisobutyronitrile, 2,2′-azobis (2-methylbutyronitrile), and 2,2′-azobis (2,4-dimethylvaleronitrile). 1,1′-azobis-1-cyclohexanecarbonitrile, dimethyl-2,2′-azobisisobutyrate, dimethyl-2,2′-azobis (2-methylpropionate), dimethyl-1,1 ′ -Azobis (1-cyclohexanecarboxylate), 4,4'-azobis (4-cyanovaleric acid), 2,2'-azobis (2-amidinopropane) dihydrochloride, 2-tert-butylazo-2-cyanopropane 2,2′-azobis (2-methylpropionamide) dihydrate, 2,2′-azobis (2,4,4-trimethylpentane), and the like.

  Examples of the diacyl peroxide compound include benzoyl peroxide, diisobutyryl peroxide, di (3,5,5-trimethylhexanoyl) peroxide, dilauroyl peroxide, and disuccinic acid peroxide. Examples of the peroxyester compound include cumylperoxyneodecanoate, 1,1,3,3-tetramethylbutylperoxyneodecanoate, tert-hexylperoxyneodecanoate, and tert-butylperoxyneo. Decanoate, tert-butylperoxyneoheptanoate, tert-hexylperoxypivalate, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, 2,5-dimethyl-2 , 5-di (2-ethylhexanoylperoxy) hexane, tert-hexylperoxy-2-ethylhexanoate, tert-butylperoxypivalate, tert-butylperoxy-2-ethylhexanoate, tert -Butyl peroxyisobutyrate, tert-butyl per Kishiraureto, tert- butylperoxy isophthalate, tert- butylperoxy acetate, tert- butylperoxy octoate and tert- butyl peroxybenzoate, and the like. Examples of the hydroperoxide compound include cumene hydroperoxide and p-menthane hydroperoxide. Examples of the peroxydicarbonate compound include di-sec-butyl peroxydicarbonate, di (4-t-butylcyclohexyl) peroxydicarbonate, di-n-propyl peroxydicarbonate, diisopropyl peroxycarbonate, and di- (2-ethylhexyl) peroxycarbonate and the like. Other examples of the peroxide include methyl ethyl ketone peroxide, potassium persulfate, and 1,1-bis (tert-butylperoxy) -3,3,5-trimethylcyclohexane.

  The decomposition temperature for obtaining the 10-hour half-life of the thermal radical initiator is preferably 30 ° C. or higher, more preferably 40 ° C. or higher, preferably 90 ° C. or lower, more preferably 80 ° C. or lower. When the decomposition temperature for obtaining the 10-hour half-life of the thermal radical initiator is less than 30 ° C., the storage stability of the anisotropic conductive paste tends to be lowered. It tends to be difficult to sufficiently heat cure the conductive paste.

  The content of the thermosetting agent is not particularly limited. Content of the said thermosetting agent is suitably adjusted according to the kind of thermosetting agent. The content of the thermosetting agent is preferably 0.01 parts by weight or more and preferably 200 parts by weight or less with respect to 100 parts by weight of the thermosetting compound.

  When the thermosetting agent is a thermosetting agent other than a thermal radical initiator, the content of the thermosetting agent is preferably 0.01 parts by weight or more, more preferably, with respect to 100 parts by weight of the thermosetting compound. Is 30 parts by weight or more, preferably 200 parts by weight or less, more preferably 100 parts by weight or less, still more preferably 75 parts by weight or less, and particularly preferably 40 parts by weight or less. When the content of the thermosetting agent is not less than the above lower limit, it is easy to sufficiently cure the anisotropic conductive paste. When the content of the thermosetting agent is not more than the above upper limit, it is difficult for an excess thermosetting agent that did not participate in curing after curing to remain, and the heat resistance of the cured product is further enhanced.

  When the thermosetting agent is a thermal radical initiator, the content of the thermal radical initiator is not particularly limited. The content of the thermal radical initiator is preferably 0.01 parts by weight or more, more preferably 0.05 parts by weight or more, preferably 10 parts by weight or less, more preferably 100 parts by weight of the thermosetting compound. 5 parts by weight or less. When the content of the thermal radical curing agent is not less than the above lower limit and not more than the above upper limit, the anisotropic conductive paste is sufficiently cured by heat.

(Photocuring initiator)
The photocuring initiator is not particularly limited. A conventionally known photocuring initiator can be used as the photocuring initiator. As for the said photocuring initiator, only 1 type may be used and 2 or more types may be used together.

  The photocuring initiator is not particularly limited, and examples thereof include acetophenone photocuring initiator, benzophenone photocuring initiator, thioxanthone, ketal photocuring initiator, halogenated ketone, acyl phosphinoxide, and acyl phosphonate. .

  Specific examples of the acetophenone photocuring initiator include 4- (2-hydroxyethoxy) phenyl (2-hydroxy-2-propyl) ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, methoxy Examples include acetophenone, 2,2-dimethoxy-1,2-diphenylethane-1-one, and 2-hydroxy-2-cyclohexylacetophenone. Specific examples of the ketal photocuring initiator include benzyldimethyl ketal.

  The content of the photocuring initiator is not particularly limited. The content of the photocuring initiator is preferably 0.1 parts by weight or more, more preferably 0.2 parts by weight or more, preferably 2 parts by weight or less, more preferably 100 parts by weight of the photocurable compound. Is 1 part by weight or less. When the content of the photocuring initiator is not less than the above lower limit and not more than the above upper limit, the anisotropic conductive paste is appropriately photocured. The anisotropic conductive paste can be prevented from flowing by irradiating the anisotropic conductive paste with light to form a B stage.

(Conductive particles)
The conductive particles contained in the anisotropic conductive paste electrically connect the flexible printed circuit board and the first and second electrodes of the connection target member. The conductive particles are not particularly limited as long as they are conductive particles. The surface of the conductive layer of the conductive particles may be covered with an insulating layer. In this case, the insulating layer between the conductive layer and the electrode is excluded when the flexible printed board and the connection target member are connected. Examples of the conductive particles include conductive particles obtained by coating the surfaces of organic particles, inorganic particles, organic-inorganic hybrid particles, or metal particles with a metal layer, and metal particles that are substantially composed of only metal. It is done. The metal layer is not particularly limited. Examples of the metal layer include a gold layer, a silver layer, a copper layer, a nickel layer, a palladium layer, and a metal layer containing tin.

  From the viewpoint of further improving the conduction reliability between the electrodes, the conductive particles preferably include resin particles and a conductive layer disposed on the surface of the resin particles.

  The average particle diameter of the conductive particles is preferably 0.5 μm or more, more preferably 1 μm or more, preferably 100 μm or less, more preferably 20 μm or less, still more preferably 15 μm or less, and particularly preferably 10 μm or less.

  The “average particle size” of the conductive particles indicates a number average particle size. The average particle diameter of the conductive particles is determined by observing 50 arbitrary conductive particles with an electron microscope or an optical microscope and calculating an average value.

  The content of the conductive particles is not particularly limited. The content of the conductive particles in 100% by weight of the anisotropic conductive paste is preferably 0.1% by weight or more, more preferably 0.5% by weight or more, still more preferably 1% by weight or more, preferably 40% by weight. % Or less, more preferably 30% by weight or less, still more preferably 19% by weight or less. A conductive particle can be easily arrange | positioned between the upper and lower electrodes which should be connected as content of the said electroconductive particle is more than the said minimum and below the said upper limit. Furthermore, it becomes difficult to electrically connect adjacent electrodes that should not be connected via a plurality of conductive particles. That is, a short circuit between adjacent electrodes can be further prevented.

(Other ingredients)
The anisotropic conductive paste preferably contains a filler. By using the filler, the latent thermal expansion of the cured anisotropic conductive paste can be suppressed. Specific examples of the filler include silica, aluminum nitride, and alumina. As for the said filler, only 1 type may be used and 2 or more types may be used together.

  The anisotropic conductive paste preferably further contains a curing accelerator. Use of the curing accelerator further increases the curing rate of the anisotropic conductive paste. As for the said hardening accelerator, only 1 type may be used and 2 or more types may be used together.

  Specific examples of the curing accelerator include imidazole curing accelerators and amine curing accelerators. Of these, imidazole curing accelerators are preferred. In addition, an imidazole hardening accelerator or an amine hardening accelerator can be used also as an imidazole hardening agent or an amine hardening agent.

  The anisotropic conductive paste may contain a solvent. By using the solvent, the viscosity of the anisotropic conductive paste can be easily adjusted. Examples of the solvent include ethyl acetate, methyl cellosolve, toluene, acetone, methyl ethyl ketone, cyclohexane, n-hexane, tetrahydrofuran, and diethyl ether.

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

Example 1
(1) Preparation of anisotropic conductive paste Bis (4-hydroxyphenyl) methane and 1,6-hexanediol diglycidyl ether are subjected to an addition polymerization reaction, whereby a skeleton derived from bis (4-hydroxyphenyl) methane and 1 , 6-hexanediol diglycidyl ether has a structural unit bonded with a skeleton derived from the main chain, and a reaction product having an epoxy group derived from 1,6-hexanediol diglycidyl ether at both ends was obtained. . Thereafter, acrylic acid was reacted to obtain an epoxy compound having an epoxy group at both ends and a vinyl group in the side chain.

  30 parts by weight of the resulting epoxy compound, 10 parts by weight of an amine adduct (“PN-23J” manufactured by Ajinomoto Fine Techno Co.) as a thermosetting agent, and an epoxy acrylate (“EBECRYL 3702 manufactured by Daicel Cytec Co., Ltd.) as a photocurable compound. ”) 8 parts by weight, 0.2 part by weight of an acylphosphine oxide compound (“ DAROCUR TPO ”manufactured by Ciba Japan) as a photopolymerization initiator, and 2-ethyl-4-methylimidazole 1 as a curing accelerator Anisotropy that blends 20 parts by weight of silica, 20 parts by weight of silica with an average particle diameter of 0.25 μm and 20 parts by weight of alumina with an average particle diameter of 0.5 μm, and further provides conductive particles with an average particle diameter of 5 μm. After adding so that the content in 100% by weight of the conductive paste is 5% by weight, 2000 rp using a planetary stirrer In by stirring for 5 minutes, to obtain an anisotropic conductive paste.

  The conductive particles used are conductive particles having a metal layer in which a nickel plating layer is formed on the surface of divinylbenzene resin particles and a gold plating layer is formed on the surface of the nickel plating layer. is there.

(2) Fabrication of connection structure A semiconductor chip having a gold-plated Cu electrode pattern with L / S of 20 μm / 20 μm, length of 2 mm, and thickness of 10 μm on the surface, and length of 15 mm, width of 2 mm, and thickness of 800 μm A flexible printed circuit board on the surface was prepared. The flexible printed board has the Cu electrode pattern on the outer periphery of one end and the semiconductor chip in the center.

  In addition, a glass substrate (member to be connected) having an aluminum electrode pattern with L / S of 20 μm / 20 μm, a length of 1 mm, and a thickness of 0.3 μm on the surface was prepared. The glass substrate has the aluminum electrode pattern on the outer peripheral edge at one end.

  In addition, a coating apparatus shown in FIG. The coating device includes a dispenser and an ultraviolet irradiation lamp that is a light irradiation device connected to the dispenser.

  The flexible printed circuit board was arranged so that the Cu electrode pattern and the semiconductor chip were positioned above. While moving the coating apparatus on the Cu electrode pattern, an anisotropic conductive paste was applied to the surface of the flexible printed board to form an anisotropic conductive material layer. The dispenser was moved from one edge in the length direction of the electrode pattern to the other edge. Further, one of the edges in the length direction of the Cu electrode pattern was used as a region for the application start portion, and the other edge in the length direction of the Cu electrode pattern was used as a region for the application end portion. In both the application start part area and the application end part, the movement direction of the dispenser is changed to a V shape by 150 degrees, and the application start part is applied in both the application start part area and the application end part area. More anisotropic conductive paste was applied than the region between the region and the region where the application was completed.

  Further, in the coating region between the coating start portion region and the coating end portion region, the edge side (outer side surface side of the glass substrate) from the center of the Cu electrode pattern in the direction orthogonal to the movement direction of the dispenser. The anisotropic conductive paste was applied from the dispenser while moving the dispenser on the Cu electrode pattern with the position of the dispenser being shifted.

  Moreover, the anisotropic conductive paste was continuously applied linearly on the electrodes of the Cu electrode pattern and on the gaps between the electrodes in the Cu electrode pattern. At this time, by controlling the discharge amount of the anisotropic conductive paste from the dispenser, the thickness of the anisotropic conductive material layer portion disposed on the electrodes and the difference disposed on the gaps between the plurality of electrodes. By controlling the thickness of the anisotropic conductive material layer portion, the anisotropic conductive material layer portion disposed on the electrode and the anisotropic conductive material layer portion disposed on the gap between the plurality of electrodes are connected. The upper surface was made smooth. The anisotropic conductive paste was not applied on the semiconductor chip of the flexible printed board.

Next, the anisotropic conductive material layer is irradiated with ultraviolet rays using an ultraviolet irradiation lamp so that the irradiation energy is 6000 mJ / cm ^2, and the anisotropic conductive material layer is semi-cured by photopolymerization to form a B stage. did. Next, the said Cu electrode pattern and the said aluminum electrode pattern were made to oppose, and the said flexible printed circuit board and the said glass substrate were laminated | stacked through the anisotropic conductive material layer made into B stage. Then, while adjusting the temperature of the head so that the temperature of the B-staged anisotropic conductive material layer becomes 185 ° C., a pressure heating head is placed on the upper surface of the glass substrate, and a pressure of 3 MPa is applied. The isotropic conductive material layer was completely cured at 185 ° C. to obtain a connection structure.

(Examples 2 to 6)
Example 1 except that the movement direction of the dispenser in the region of the application start part and the region of the application end part, the change angle of the movement direction, and the average particle diameter of the conductive particles were set as shown in Table 1 below. Similarly, a connection structure was obtained.

(Examples 7 to 9)
A flexible printed circuit board used for manufacturing a connection structure has a gold-plated Cu electrode pattern with L / S of 30 μm / 30 μm, a length of 2 mm, and a thickness of 30 μm on the surface, and a length of 15 mm, a width of 2 mm, and a thickness. Changed to a flexible printed circuit board having a semiconductor chip of 800 μm on the surface, and the second connection target member has an aluminum electrode pattern with an L / S of 30 μm / 30 μm, a length of 1 mm, and a thickness of 0.3 μm on the surface Table 1 below shows the change to the glass substrate, the movement direction of the dispenser in the region of the application start portion and the region of the application end portion, the change angle of the movement direction, and the average particle diameter of the conductive particles. A connection structure was obtained in the same manner as in Example 1 except that it was set to.

(Example 10)
When preparing the anisotropic conductive paste, 8 parts by weight of epoxy acrylate (“EBECRYL 3702”, manufactured by Daicel-Cytec), which is a photocurable compound, and urethane acrylate (“EBECRYL8804, manufactured by Daicel-Cytec, Inc.), which is a photocurable compound, are used. ]) An anisotropic conductive paste was obtained in the same manner as in Example 1 except that the amount was changed to 8 parts by weight. In addition, using the obtained anisotropic conductive paste, the movement direction of the dispenser in the region of the application start portion and the region of the application end portion, the change angle of the movement direction, and the average particle diameter of the conductive particles A connection structure was obtained in the same manner as in Example 1 except that settings were made as shown in Table 1 below.

(Comparative Example 1)
Without changing the movement direction of the dispenser in both the application start part area and the application end part area, the dispenser is moved linearly in both the application start part area and the application end part area. A connection structure was obtained in the same manner as in Example 1 except that the application area between the application start area and the application end area and the application amount of the anisotropic conductive paste were the same.

(Comparative Example 2)
A connection structure was obtained in the same manner as in Example 1 except that the anisotropic conductive paste was uniformly applied over the entire surface of the electrode of the Cu electrode pattern of the flexible printed board.

(Evaluation)
(1) Viscosity η1 and viscosity ratio (η2 / η3)
Using an E-type viscometer (manufactured by Toki Sangyo Co., Ltd.), the viscosity η1 of the obtained anisotropic conductive paste (viscosity of the anisotropic conductive paste before application) was measured at 25 ° C. and 2.5 rpm. did. Moreover, the viscosity η2 at 25 ° C. and 2.5 rpm and the viscosity η3 at 25 ° C. and 5 rpm were measured using the E-type viscometer.

(2) Conduction reliability (conductivity test between upper and lower electrodes at the end)
The connection resistance between the upper and lower electrodes was measured by the four-terminal method in the end wirings (20 places) of the 10 connection structures obtained. The average value and standard deviation of 20 connection resistances were calculated. Note that the connection resistance can be obtained by measuring the voltage when a constant current is passed from the relationship of voltage = current × resistance. The case where the standard deviation of the connection resistance was 1Ω or less was judged as “◯”, and the case where the standard deviation of the connection resistance exceeded 1Ω was judged as “X”.

(3) Connection reliability (peel strength)
A 90-degree peel test was performed on 10 obtained connection structures. The case where the average measurement value was 10 N / cm or more was determined as “◯”, and the case where the average measurement value was less than 10 N / cm was determined as “x”.

  The results are shown in Table 1 below. The conductive particles used in the examples and comparative examples are all metals in which a nickel plating layer is formed on the surface of the divinylbenzene resin particles and a gold plating layer is formed on the surface of the nickel plating layer. A conductive particle having a layer.

  The results are shown in Table 1 below.

DESCRIPTION OF SYMBOLS 1 ... Connection structure 2 ... 2nd connection object member 2a ... Surface 2b ... 2nd electrode 3 ... Hardened | cured material layer 3a ... Upper surface 3A ... Anisotropic conductive material layer 3B ... An anisotropic conductive material made into B stage Layer 4 ... Flexible printed circuit board 4a ... Surface 4b ... First electrode 4c ... Electronic component 5 ... Conductive particles 11 ... Application device 12 ... Dispenser 12a ... Syringe 12b ... Grasping part 12c ... Tip 13 ... Light irradiation device 13a ... Light irradiation Device main body 13b ... Light irradiation unit 31 ... Stand 61 ... Flexible printed circuit board 61a ... Surface 61b ... First electrode 61c ... Electronic component

Claims (9)

Using a flexible printed board having a first electrode on its surface, anisotropic conductive using an anisotropic conductive paste containing a curable component and conductive particles on the first electrode of the flexible printed board Arranging a material layer;
Using the second connection target member having the second electrode on the surface, the first electrode and the second electrode are opposed to each other, and the flexible printed circuit board and the second connection target member are Laminating via the anisotropic conductive material layer;
Curing the anisotropic conductive material layer to form a cured product layer,
In the step of disposing the anisotropic conductive material layer, the anisotropic conductive paste is applied from the dispenser while moving the dispenser on the first electrode,
The anisotropic conductive paste is applied in at least one of the application start part area and the application end part area more than the application area between the application start part area and the application end part area. Apply a lot ,
At least one of the application area of the region of the area and the coating end portion of the coating start portion, Ru changing the moving direction of the dispenser, the manufacturing method of the connection structure. The method for manufacturing a connection structure according to claim 1, wherein the movement direction of the dispenser is changed by 30 degrees or more and 180 degrees or less in at least one of the application start area and the application end area. The method of manufacturing a connection structure according to claim 1 or 2 , wherein the direction of movement of the dispenser is changed to a V shape or a U shape in at least one of the application start region and the application end region. . One edge portion of the cured product layer is formed by the anisotropic conductive paste applied at the start of application, and the other edge portion of the cured product layer is applied at the end of application. Formed by
At least one of the one edge and the other edge of the cured product layer is more than the center of the cured product layer between the one edge and the other edge of the cured product layer. The manufacturing method of the connection structure of any one of Claims 1-3 which increases the abundance of a hardened | cured material layer. A fillet made of the cured product layer is provided in at least one of the outer side surface of the flexible printed circuit board and at least one side of the outer side surface of the second connection target member. The manufacturing method of the connection structure of any one of Claims 1-4 which forms. The manufacturing method of the connection structure of Claim 5 which forms the fillet by the said hardened | cured material layer in at least one of the one edge part and the other edge part of the said hardened | cured material layer. Forming a fillet by the cured product layer at one edge and the other edge of the cured product layer, and a central portion between the one edge and the other edge of the cured product layer,
The protruding distance from the outer peripheral side surface of the flexible printed circuit board or the second connection target member of the fillet at one edge portion and the other edge portion of the cured product layer is set as one edge portion and the other of the cured product layer. of the larger than protrusion distance from the outer peripheral side surface of the flexible printed circuit board or the second connection object member of the fillet at the central portion of the cured layer between the edge, according to claim 5 or 6 A manufacturing method of a connection structure. In the application region between the region of the application start portion and the region of the application end portion, the position of the dispenser is positioned closer to the edge than the center of the first electrode in the direction orthogonal to the movement direction of the dispenser. The manufacturing of the connection structure according to any one of claims 1 to 7 , wherein the anisotropic conductive paste is applied from the dispenser while moving the dispenser on the first electrode in a shifted state. Method. The flexible printed circuit board has a first electrode that protrudes to the surface, and having said first electronic component protruding greater protruding height than the electrode to the surface, either of claims 1-8 1 The manufacturing method of the connection structure as described in a term.

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