JP5844599B2 - CONNECTION DEVICE, CONNECTION MANUFACTURING METHOD, CONNECTION METHOD - Google Patents

Description

  The present invention relates to a connection device for double-sided mounting that connects an electronic component to the other surface of a substrate on which the electronic component is mounted on one surface, a connection method using the same, and a method for manufacturing a connection body.

  Conventionally, as a method for mounting electronic components on a substrate, there is a method using an anisotropic conductive film in addition to a method using solder. As the anisotropic conductive film, for example, a film obtained by dispersing spherical or scaly conductive particles having an average particle diameter of the order of several μm in a thermosetting binder resin composition is used.

  The anisotropic conductive film is interposed between the electrode of the mounting part on which the electronic component of the substrate is mounted and the electronic component, and then thermally pressed from above the electronic component by a heating bonder, so that the binder resin is While flowing out from between the electrode and the electronic component while exhibiting fluidity, the conductive particles conduct between the electrode and the electronic component, and in this state, the binder resin is thermoset.

  By the way, in recent years, mainly in devices such as mobile phones and notebook personal computers, higher density mounting has been demanded due to the background of progress in advanced functions as well as downsizing, weight reduction and thinning. In order to realize high-density mounting in such a small, lightweight, and thin device, double-sided mounting in which electronic components are mounted on both sides of the substrate is an effective means.

  However, the method using an anisotropic conductive film involves heat pressing with a heating bonder, so when mounting an electronic component on the opposite side of a substrate that already has an electronic component mounted on one side, The mounted electronic component is subjected to pressure by a heating bonder, and there is a possibility that the electronic component is damaged or the bonded portion is peeled off or cracked.

  As a countermeasure against this, a method has been proposed in which a cushioning material is arranged between the mounted electronic component and the cradle of the connection device (see, for example, Patent Document 1 and Patent Document 2). However, with this method, when the heights of mounted electronic components are different, it is difficult to uniformly apply pressure to each mounted component, which may cause damage to the mounted components that are tall. It was.

  In addition, the pressure of the heating bonder applied to the electronic component mounted on the opposite surface of the substrate on which the electronic component is mounted on one side becomes uneven due to the height difference of the mounted electronic component. In mounting using an anisotropic conductive film, conductive connection is achieved by pressurizing at an appropriate pressure. Therefore, if the pressure by the heating bonder is excessive or insufficient, the connection reliability of electronic components may be inferior. .

  There has also been proposed a method in which a concave portion corresponding to the height of a mounted component is provided on the surface in contact with the mounted component of the cushioning material in advance (see Patent Document 3). However, according to this method, it is necessary to strictly control the depth of the concave portion, and abrupt pressure is applied during crimping, which may cause damage to electronic components.

JP 2007-214434 A JP 2001-160569 A JP 2009-105204 A

  Therefore, the present invention improves the connection reliability by applying pressure evenly to the electronic parts arranged via the adhesive, and prevents damage to the mounted parts, peeling of the bonded parts, etc. It is an object of the present invention to provide a connection device, a connection body manufacturing method, and a connection method that can be mounted.

In order to solve the above-described problems, a connection device according to the present invention includes a cradle that supports a substrate on which an electronic component is mounted on one surface, and the substrate on the opposite side of the mounting portion on which the electronic component is mounted. on the other side, a head for pressing the connecting members disposed over the adhesive, disposed opposite to the head on the cradle on, and a cushioning material for supporting the one side of the substrate, the The cushioning material has a rubber hardness of 60 or less, and the cushioning material is formed of an elastic material, and a surface supporting the one surface is flattened, and the mounting is performed on the surface opposite to the planarized surface. A concave portion is provided corresponding to the position where the portion is placed, and the depth d1 of the concave portion is the same as the electronic component of the mounting portion and the other electronic component mounted on the one surface and lower in height than the electronic component of the mounting portion. Or a height difference td or more between the mounting portion and the adjacent region. The cushioning material from the thickness t1 minus the depth d1 of the recess cushioning material body portion thickness of (t1-d1) is the height t2 or more electronic components of the mounting portion.

Further, in the method for manufacturing a connection body according to the present invention, the one surface of the substrate on which the electronic component is mounted on one surface is placed on a cushioning material provided on a cradle, and the electronic component is mounted on the mounting surface. A connecting member is disposed on the other surface of the substrate on the opposite side of the part with an adhesive, and the connecting member is pressurized by a head provided to face the cushioning material. The rubber hardness is 60 or less, and the cushioning material is formed of an elastic material, the surface supporting the one surface side is flattened, and the mounting portion is on the surface opposite to the flattened surface. A concave portion is provided corresponding to the mounting position, and the depth d1 of the concave portion is mounted on the electronic component of the mounting portion and the other electronic component having a lower height than the electronic component of the mounting portion or the electronic component of the mounting portion. The height difference between the mounting portion and the adjacent region is td or more, and the cushioning material Cushioning material body portion thickness of from thickness t1 minus the depth d1 of the recess (t1-d1) is the height t2 or more electronic components of the mounting portion.

Further, the connection method according to the present invention is such that the one surface of the substrate on which the electronic component is mounted on one surface is placed on a cushioning material provided on the cradle, and is opposite to the mounting portion on which the electronic component is mounted. The connecting member is disposed on the other surface of the substrate on the side through an adhesive, and the connecting member is pressed by a head provided opposite to the cushioning material . The cushioning material has a rubber hardness. There is 60 or less, the cushioning material, while being formed of an elastic material, are planarized surface for supporting the one side, the mounting portion is placed on the surface opposite to the above surface planarized A concave portion corresponding to the position of the mounting portion, and the depth d1 of the concave portion is different from the electronic component of the mounting portion and the other electronic component mounted on the one surface and lower in height than the electronic component of the mounting portion or the mounting portion. The height difference td between adjacent regions is greater than the thickness t of the cushioning material. From minus depth d1 of the recess cushioning material body portion thickness (t1-d1) is the height t2 or more electronic components of the mounting portion.

  According to the present invention, the depth d1 and the height difference td between the electronic component mounted on the mounting part and the adjacent region of the other electronic component 11 or the mounting part satisfy d1 ≧ td. By supporting one surface of the substrate with the entire flat surface of the cushioning material and pressing the connection member disposed on the other surface of the substrate with the head, the connection member other than the mounting portion and the mounting portion other than the mounting portion are pressed. It is possible to absorb the pressure difference of the head applied to the connecting member disposed on the opposite side of the region. Therefore, the connecting member disposed on the other surface of the substrate via the adhesive can be pressed evenly with an appropriate pressure, and the connection reliability can be improved.

  In addition, according to the present invention, it is possible to absorb a stress difference between the electronic component on the mounting portion and the electronic component mounted in a region other than the mounting portion, and damage of the mounted electronic component or the connection location Separation and the like can be prevented.

  In addition, the recess has a thickness (t1-d1) of the main body portion obtained by subtracting the depth d1 of the recess from the thickness t1 of the cushioning material and a height t2 of the electronic component mounted on the mounting portion (t1-d1). ) By satisfying ≧ t2, it is possible to prevent the pressure of the head from concentrating on the connection member arranged on the opposite side of the mounting portion, and to absorb the stress applied to the electronic components mounted on the mounting portion, Peeling from the mounting portion can be prevented. Therefore, according to the present invention, it is possible to reliably perform double-sided mounting by using an adhesive to prevent damage to mounted components, separation of bonded portions, and the like.

It is a side view showing a connection device to which the present invention is applied. It is a side view which shows a buffer material. It is a side view which shows a wiring board. It is a perspective view which shows an example of a recessed part. It is sectional drawing which shows an anisotropic conductive film. It is a side view which shows the anisotropic conductive film supported by the peeling film and wound by the reel shape. It is a side view which shows an example of the connection method. It is the bottom view and side view explaining an Example. It is the bottom view and side view explaining an Example. It is the bottom view and side view explaining an Example.

  Hereinafter, a connection device, a connection body manufacturing method, and a connection method to which the present invention is applied will be described in detail with reference to the drawings. It should be noted that the present invention is not limited to the following embodiments, and various modifications can be made without departing from the scope of the present invention. Further, the drawings are schematic, and the ratio of each dimension may be different from the actual one. Specific dimensions should be determined in consideration of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

  The connection device 1 to which the present invention is applied is used, for example, when mounting electronic components on both sides of a substrate such as a rigid printed wiring board or a flexible printed wiring board.

[Wiring board]
First, the wiring board 10 for double-side mounting on which electronic components are mounted using the connection device 1 will be described. As shown in FIG. 1, various substrates such as a so-called rigid printed wiring board, a flexible printed wiring board, a flex rigid board, and a glass substrate can be used as the wiring board 10. The wiring substrate 10 has a wiring pattern formed on one surface 10a at a fine pitch, and a plurality of electronic components 11 having different heights are mounted thereon. Examples of the electronic component 11 include a resistor, a capacitor, and an IC chip.

  This wiring board 10 is a board for double-sided mounting, and as shown in FIG. 1, among the electronic parts 11 mounted on one surface 10a, a region where the highest electronic part 11a is mounted is mounted. 12, an electrode is formed on the other surface 10b on the opposite side of the mounting portion 12, and the electronic component 13 is connected. Examples of the electronic component 13 include a flexible flat cable, a flexible printed wiring board, a resistor, a capacitor, and an IC chip. FIG. 1 illustrates a state in which a flexible printed wiring board is used as the electronic component 13.

  The wiring board 10 is an electronic component disposed on an electrode on the other surface 10b with an anisotropic conductive adhesive 17 described later in a state where the one surface 10a is supported by the buffer material 4 provided in the connection device 1. 13 is heated and pressed by the heating and pressing head 3 at a predetermined temperature, pressure, and time, whereby the electronic component 13 is electrically connected to the electrode on the other surface 10b. In FIG. 1, the flexible printed wiring board (electronic component 13) is formed in the same direction as a plurality of electrodes (not shown) formed on the other surface 10 b across the width direction of the wiring board 10 shown in the figure. A plurality of electrodes (not shown) are connected via an anisotropic conductive adhesive 17.

[Connecting device 1]
Next, the connection device 1 that connects the electronic component 13 to the wiring board 10 will be described. As shown in FIG. 1, the connection device 1 heats a cradle 2 that supports a wiring board 10 and an electronic component 13 that is placed on the wiring board 10 via an anisotropic conductive adhesive 17 described later. The heating and pressing head 3 to be pressed, and the mounting portion 12 provided on the cradle 2 so as to face the heating and pressing head 3 on which the electronic component 11 is mounted in advance are supported, and the pressing force by the heating and pressing head 3 is applied. A buffer material 4 to be absorbed.

  The cradle 2 is made of, for example, a plate-like ceramic, and a cushioning material 4 is provided on the upper surface, and the wiring board 10 is placed on the cushioning material 4.

  The heating and pressing head 3 heat-presses the electronic component 13 to thermally cure the anisotropic conductive adhesive 17, thereby electrically connecting the electronic component 13 and the electrode on the other surface 10 b of the wiring board 10. The heating and pressing head 3 has a built-in heater and is supported by an elevating mechanism (not shown) so that the heat pressurizing surface can be moved close to and away from the cradle 2, and is placed on the cradle 2 via the buffer material 4. The electronic component 13 can be heat-pressed against the printed wiring board 10.

[Buffer material 4]
The buffer material 4 supports the mounting portion 12 provided on the one surface 10 a of the wiring substrate 10, thereby absorbing the pressure by the heating and pressing head 3 and absorbing the pressure difference between the mounting portion 12 and a region other than the mounting portion 12. Then, uniform heat and pressure are applied to the electronic component 13 disposed on the other surface 10b of the wiring board 10. At the same time, the cushioning material 4 prevents damage to the electronic component 11a mounted on the mounting portion 12, peeling of the bonded portion, and the like. The buffer material 4 is made of, for example, an elastic body such as a silicone resin, and is formed in a substantially rectangular shape as a whole. In addition, the cushioning material 4 has a flat surface 4a that supports the one surface 10a of the wiring board 10, and a concave portion 5 corresponding to a position where the mounting portion 12 is placed on the other surface 4b opposite to the flat surface 4a. Is formed.

  And the buffer material 4 is used for the other surface 4b in which the recessed part 5 was formed toward the receiving stand 2 side, and the flat surface 4a side toward the upper side. The buffer 4 supports the wiring substrate 10 uniformly by supporting the one surface 10 a of the wiring substrate 10 with the entire flat surface 4 a with the flat surface 4 a facing upward, and the entire supporting surface with the heating and pressing head 3. Can be uniformly pressurized.

  The concave portion 5 formed on the other surface 4b of the cushioning material 4 disperses the stress applied to the electronic component 11a mounted on the mounting portion 12 together with the cushioning material main body portion 4c on the concave portion 5, and the mounting portion 12 and the mounting portion 12 This is to eliminate the pressure difference of the heating / pressing head 3 in the other area. The recess 5 is formed by mounting the electronic component 11 mounted on the mounting portion 12 and the electronic component 11 mounted on a portion other than the mounting portion 12 on the first surface 10a of the wiring board 10. It has a shape corresponding to the height difference from the component 11a.

  That is, as shown in FIG. 2 and FIG. 3, the recess 5 has a depth d1 that is lower than the electronic component 11 of the mounting portion 12 mounted in the electronic component 11a of the mounting portion 12 and a region adjacent to the mounting portion 12. When an electronic component is not mounted in another electronic component 11 or an area adjacent to the mounting portion 12, the height difference from the adjacent area is equal to or greater than td (d1 ≧ td).

  Further, in the recess 5, the thickness (t1-d1) of the main body portion 4c obtained by subtracting the depth d1 of the recess 5 from the thickness t1 of the cushioning material is equal to or greater than the height t2 of the electronic component 11a of the mounting portion 12. ((T1-d1) ≧ t2).

  The recess 5 has a flat surface of the cushioning material 4 when the depth d1 and the height difference td between the electronic component 11a mounted on the one surface 10a and another electronic component 11 or an adjacent region satisfy d1 ≧ td. When the one surface 10a of the wiring board 10 is supported by the whole 4a, the pressure difference to the electronic component 13 disposed on the other surface 10b due to the height difference from the electronic component 11a on the one surface 10a is eliminated, and the mounting portion The stress difference applied to the electronic component 11a on the electronic component 11 and the electronic component 11 mounted in a region other than the mounting portion 12 can be absorbed.

  That is, when the wiring substrate 10 is heated and pressed by the heating and pressing head 3 and one surface 10a of the wiring substrate 10 is supported by the flat surface 4a, the electronic component supported by the flat surface 4a is mounted on the mounting portion 12. The high-profile electronic component 11a has a stress difference due to the height difference from the low-profile electronic component 11 mounted in a region other than the mounting portion 12. Further, the heating and pressing head is caused by the height difference between the electronic component 13 disposed on the opposite side of the mounting portion 12 and the electronic component 13 disposed on the opposite side of the region other than the mounting portion 12. A pressure difference of 3 occurs. Accordingly, the cushioning material 4 has a depth d1 of the concave portion 5 that is greater than the height difference td between the electronic component 11a mounted on the one surface 10a and another electronic component 11 or an adjacent region. The concave portion 5 bends according to the difference td, and the stress difference and pressure difference caused by the height difference can be absorbed and eliminated.

  The recess 5 includes a thickness (t1-d1) of the main body 4c obtained by subtracting the depth d1 of the recess 5 from the thickness t1 of the cushioning material 4, and a height t2 of the electronic component 11a mounted on the mounting portion 12. And (t1−d1) ≧ t2 prevents the pressure of the heating and pressing head 3 from concentrating on the electronic component 13 disposed on the opposite side of the mounting portion 12 and is mounted on the mounting portion 12. The stress applied to the electronic component 11a can be absorbed, and breakage, peeling from the mounting portion 12, and the like can be prevented.

  That is, the electronic component 13 disposed on the opposite side of the mounting portion 12 is thinner than the depth d1 of the concave portion 5 when the cushioning material main body 4c immediately above the concave portion 5 is thin and less than the height t2 of the electronic component 11a. In addition, the stress applied to the electronic component 11a cannot be received by the main body portion 4c, and the electronic component 13 or the electronic component 11a may be damaged, or peeling from the mounting portion 12 or a crack may occur in the connection portion. Therefore, the cushioning material 4 is configured so that the thickness (t1-d1) of the cushioning material main body 4c immediately above the recess 5 and the height t2 of the electronic component 11a satisfy (t1-d1) ≧ t2. The buffer material body 4c that supports 12 absorbs the stress applied to the electronic component 13 and the electronic component 11.

  Note that the stress applied to the electronic component 13 disposed on the opposite side of the region other than the mounting portion 12 and the electronic component 11 mounted in the region other than the mounting portion 12 is other than that of the buffer material 4 that is thicker than the main body portion 4c. Therefore, the electronic component 11 is prevented from being damaged or peeled off.

  Further, the bottom surface of the recess 5 has an area equal to or larger than the mounting portion 12. That is, the bottom surface of the recess 5 has an area equal to or larger than the mounting area of all the electronic components 11 a mounted on the mounting portion 12. Thereby, the concave portion 5 disperses the pressure applied to the electronic component 13 disposed on the opposite side of the mounting portion 12, absorbs the stress applied to all the electronic components 11a mounted on the mounting portion 12, and is damaged or damaged. Peeling from the mounting portion 12 can be prevented.

  As described above, the cushioning material 4 is generated due to the height difference between the electronic component 11 a mounted on the mounting portion 12 and the electronic component 11 mounted on a region other than the mounting portion 12 due to the recess 5. The pressure difference of the heating and pressing head 3 applied to the electronic component 13 disposed on the opposite side of the mounting portion 12 and the electronic component 13 disposed on the opposite side of the region other than the mounting portion 12, or the mounting portion 12 is mounted. While absorbing the stress difference between the electronic component 11a and the electronic component 11 mounted other than the mounting portion 12, the electronic component 13 and the mounting disposed on the opposite side of the mounting portion 12 by the main body portion 4c immediately above the recess 5 The stress applied to the electronic component 11 mounted on the portion 12 is absorbed. Therefore, according to the connection apparatus 1, while pressing the electronic component 13 arrange | positioned at the other surface 10b equally with an appropriate pressure, and improving connection reliability, the electronic components 11 and 11a mounted in the one surface 10a are improved. Damage or peeling can be prevented, and double-sided mounting can be reliably performed on the wiring board 10.

  The buffer material 4 can be used with a rubber hardness (JIS K6253 type A) of less than 60, and is preferably used in the range of 20-40.

  The concave portion 5 is formed in various shapes according to the mounting pattern of the mounting portion 12 and the electronic component 11. For example, as shown in FIG. 4 (a), the recess 5 is formed as a rectangular recess, and as shown in FIG. 4 (b), a plurality of grooves whose ends face both side surfaces of the cushioning material 4 are formed. It is formed in a shape. The recess 5 is formed in a groove shape with end portions facing both side surfaces of the cushioning material 4, so that air in the recess 5 can be easily released when pressure is applied. The concave portion 5 is formed by cutting a buffer material block such as silicone rubber into a predetermined size.

[Anisotropic conductive adhesive]
Next, the anisotropic conductive adhesive 17 that is attached to the other surface 10 b of the wiring substrate 10 and connects the electronic component 13 by being thermally pressed by the heating and pressing head 3 will be described. For example, as shown in FIG. 5, the anisotropic conductive adhesive 17 is conductive to a normal binder (adhesive) 23 containing a film-forming resin, a thermosetting resin, a latent curing agent, a silane coupling agent, and the like. The particles 24 are dispersed. Hereinafter, the anisotropic conductive film 17 formed into a film shape will be described as an example. The anisotropic conductive film 17 is heated and pressed by the heating and pressing head 3 to cure the binder 23, and between the connection electrode provided on the other surface 10 b of the wiring substrate 10 and the electrode of the electronic component 13. The conductive particles 24 are sandwiched between the electrodes, thereby achieving electrical and mechanical connection between the two electrodes.

  As shown in FIG. 6, the anisotropic conductive film 17 is formed on the release film 25 by applying an anisotropic conductive composition comprising a binder 23 in which conductive particles 24 are dispersed on the release film 25. Is done. The release film 25 is formed by, for example, applying a release agent such as silicone to PET (Poly Ethylene Terephthalate), OPP (Oriented Polypropylene), PMP (Poly-4-methlpentene-1), PTFE (Polytetrafluoroethylene), etc. While preventing the conductive conductive film 17 from drying, the shape of the anisotropic conductive film 17 can be maintained.

  The film forming resin contained in the binder 23 is preferably a resin having an average molecular weight of about 10,000 to 80,000. Examples of the film forming resin include various resins such as an epoxy resin, a modified epoxy resin, a urethane resin, and a phenoxy resin. Among these, phenoxy resin is particularly preferable from the viewpoint of film formation state, connection reliability, and the like.

  It does not specifically limit as a thermosetting resin, For example, a commercially available epoxy resin, an acrylic resin, etc. are mentioned.

  The epoxy resin is not particularly limited. For example, naphthalene type epoxy resin, biphenyl type epoxy resin, phenol novolac type epoxy resin, bisphenol type epoxy resin, stilbene type epoxy resin, triphenolmethane type epoxy resin, phenol aralkyl type epoxy resin. Naphthol type epoxy resin, dicyclopentadiene type epoxy resin, triphenylmethane type epoxy resin and the like. These may be used alone or in combination of two or more.

  There is no restriction | limiting in particular as an acrylic resin, According to the objective, an acrylic compound, liquid acrylate, etc. can be selected suitably. For example, methyl acrylate, ethyl acrylate, isopropyl acrylate, isobutyl acrylate, epoxy acrylate, ethylene glycol diacrylate, diethylene glycol diacrylate, trimethylolpropane triacrylate, dimethylol tricyclodecane diacrylate, tetramethylene glycol tetraacrylate, 2-hydroxy- 1,3-diacryloxypropane, 2,2-bis [4- (acryloxymethoxy) phenyl] propane, 2,2-bis [4- (acryloxyethoxy) phenyl] propane, dicyclopentenyl acrylate, tricyclo Examples include decanyl acrylate, tris (acryloxyethyl) isocyanurate, urethane acrylate, and epoxy acrylate. In addition, what made acrylate the methacrylate can also be used. These may be used individually by 1 type and may use 2 or more types together.

  The latent curing agent is not particularly limited, and examples thereof include various curing agents such as a heat curing type and a UV curing type. The latent curing agent does not normally react, but is activated by various triggers selected according to applications such as heat, light, and pressure, and starts the reaction. The activation method of the thermal activation type latent curing agent includes a method of generating active species (cation, anion, radical) by a dissociation reaction by heating, etc., and it is stably dispersed in the epoxy resin near room temperature, and epoxy at high temperature There are a method of initiating a curing reaction by dissolving and dissolving with a resin, a method of initiating a curing reaction by eluting a molecular sieve encapsulated type curing agent at a high temperature, and an elution / curing method using microcapsules. Thermally active latent curing agents include imidazole, hydrazide, boron trifluoride-amine complexes, sulfonium salts, amine imides, polyamine salts, dicyandiamide, etc., and modified products thereof. The above mixture may be sufficient. Among these, a microcapsule type imidazole-based latent curing agent is preferable.

  Although it does not specifically limit as a silane coupling agent, For example, an epoxy type, an amino type, a mercapto sulfide type, a ureido type etc. can be mentioned. By adding the silane coupling agent, the adhesion at the interface between the organic material and the inorganic material is improved.

  Examples of the conductive particles 24 include any known conductive particles used in the anisotropic conductive film 17. Examples of the conductive particles 24 include particles of various metals and metal alloys such as nickel, iron, copper, aluminum, tin, lead, chromium, cobalt, silver, gold, metal oxide, carbon, graphite, glass, ceramic, Examples thereof include those in which the surface of particles such as plastic is coated with metal, or those in which the surface of these particles is further coated with an insulating thin film. In the case where the surface of the resin particle is coated with metal, examples of the resin particle include an epoxy resin, a phenol resin, an acrylic resin, an acrylonitrile / styrene (AS) resin, a benzoguanamine resin, a divinylbenzene resin, a styrene resin, and the like. Can be mentioned.

  In the present embodiment, instead of the anisotropic conductive film 17, an insulating adhesive film (NCF (Non Conductive Film)) made only of the binder 23 may be used. In this case, the electrodes of the wiring board 10 and the electronic component 13 are brought into conduction by direct contact.

  In addition, the anisotropic conductive film 17 is good also as a structure which provides a peeling film also in the surface side opposite to the surface where the peeling film 25 was laminated | stacked from viewpoints of the ease of handling, storage stability, etc. The shape of the anisotropic conductive adhesive film 17 is not particularly limited. For example, as shown in FIG. 4, the anisotropic conductive adhesive film 17 has a long tape shape that can be wound around a take-up reel 26 made of plastic or the like, and has a predetermined length. Can only be cut and used.

  In the above-described embodiment, the anisotropic conductive film 17 in which the binder 23 containing the binder 23 and the conductive particles 24 is formed into a film shape as the anisotropic conductive adhesive has been described as an example. The anisotropic conductive adhesive according to the present invention is not limited to this. For example, two or more layers each of an insulating adhesive layer made of only the binder 23 and a conductive particle-containing layer made of the binder 23 containing the conductive particles 24 are used. It can be set as the provided structure. Further, the anisotropic conductive adhesive is not limited to the anisotropic conductive film formed by such a film, for example, a conductive adhesive paste in which conductive particles are dispersed in an insulating adhesive composition, Alternatively, an insulating adhesive paste made only of an insulating adhesive composition may be used. The adhesive according to the present invention includes any of the forms described above.

[Connection method]
Next, a process of mounting the electronic component 13 on the other surface 10b of the wiring board 10 on which the electronic component 11 is previously mounted on one surface 10a using the heating and pressing head 3 will be described. First, the wiring board 10 is disposed on the buffer material 4 of the connection device 1. The cushioning material 4 is disposed on the cradle 2 with the other surface 4b on which the concave portion 5 is formed facing the surface of the cradle 2 and the flat surface 4a facing upwardly facing the heating and pressing head 3.

  On the wiring board 10, the electronic component 11 a is mounted on the mounting portion 12 on the one surface 10 a, and the electrodes connected to the electronic component 13 on the other surface 10 b are opposite to the mounting portion 12 and areas other than the mounting portion 12. An anisotropic conductive film 17 is temporarily attached to the electrode portion. The anisotropic conductive film 17 is pulled out from the take-up reel 26 and cut to a length corresponding to the electrode arrangement of the electronic component 13, and then the binder 23 is fluidized by a temporary attachment head (not shown), but is fully cured. Is temporarily attached to the other surface 10b of the wiring board 10 by heat-pressing at a temperature (for example, 40 to 60 ° C.) for a predetermined time (for example, 1 to 5 seconds) and a predetermined pressure (for example, 0.5 MPa) Is done.

  Further, the wiring substrate 10 is placed so that one surface 10 a is supported by the flat surface 4 a of the buffer material 4. At this time, the wiring board 10 is aligned so that the mounting portion 12 is positioned on the recess 5.

  Next, an electronic component 13 such as a flexible printed wiring board is disposed on the anisotropic conductive film 17, and the heating and pressing head 3 heated to a predetermined temperature (for example, 130 to 180 ° C.) is subjected to a predetermined pressure (for example, 1 to 1). 5 MPa), the electronic component 13 is heat-pressed for a predetermined time (for example, 10 to 15 seconds), and is finally pressure-bonded to the other surface 10 b of the wiring board 10. At this time, in the anisotropic conductive film 17, the binder 23 having fluidity flows out from between the electrode on the wiring board 10 side and the electrode of the electronic component 13, and the conductive particles 24 are sandwiched between the two electrodes. In this state, the binder 23 is thermally cured. Therefore, the anisotropic conductive film 17 can electrically and mechanically connect the electronic component 13 to the other surface 10 b of the wiring board 10.

  When the heating and pressing head 3 heat-presses the electronic component 13, the buffer material 4 receives pressure from the heating and pressing head 3 and the concave portion 5 is bent inward. As a result, the wiring board 10 absorbs stress applied to the electronic component 11 a mounted on the mounting portion 12 by the recess 5 of the buffer material 4. That is, the buffer material 4 has a depth d1 of the recess 5 and a height difference td between the electronic component 11a mounted on the one surface 10a and another electronic component 11 or an adjacent region satisfies d1 ≧ td. When one surface 10a of the wiring board 10 is supported by the entire flat surface 4a of the cushioning material 4, a stress difference applied to the electronic component 11a on the mounting portion 12 and the electronic component 11 mounted in a region other than the mounting portion 12 is increased. Can be absorbed.

  The buffer material 4 includes an electronic component 11 a mounted on the mounting portion 12 on the one surface 10 a of the wiring substrate 10, an electronic component 11 mounted on a region other than the mounting portion 12, or a region adjacent to the mounting portion 12. When the electronic component is not mounted on the board, the pressure difference due to the heating and pressing head 3 generated in the electronic component 13 disposed on the other surface 10b of the wiring board 10 due to the height difference td from the adjacent region is absorbed. Then, the anisotropic conductive film 17 can be evenly pressed with an appropriate pressure.

  The buffer material 4 includes the thickness (t1-d1) of the main body portion 4c immediately above the recess 5 obtained by subtracting the depth d1 of the recess 5 from the thickness t1 of the buffer material 4, and the electronic component mounted on the mounting portion 12. When the height t2 of 11a satisfies (t1-d1) ≧ t2, the stress applied to the electronic component 13 disposed on the opposite side of the mounting portion 12 and the electronic component 11a mounted on the mounting portion 12 is absorbed. In addition to pressing the electronic component 13 with an appropriate pressure, it is possible to prevent damage to the electronic component 11a, peeling from the mounting portion 12, and the like.

  As described above, according to the connection device 1, the other electronic component 13 can be easily placed on the other surface 10 b of the wiring substrate 10 on which the electronic components 11 and 11 a are previously mounted on the one surface 10 a by using the anisotropic conductive film 17. Can be connected. In addition, the connection device 1 is caused by the height difference on the one surface 10a of the wiring board 10 by supporting the recess 5 provided in the cushioning material 4 and the mounting portion 12 on which the electronic component 11a is mounted in correspondence. The pressure difference of the heating and pressing head 3 generated in this way is absorbed, and the electronic component 13 connected to the other surface 10b of the wiring board 10 via the anisotropic conductive film 17 is pressed uniformly, and the electronic component 11a is damaged or peeled off. Generation of cracks and the like can be prevented. Therefore, the connection device 1 can perform double-sided mounting on the wiring board 10 using the anisotropic conductive film 17.

  In addition, when the recessed part 5 makes symmetrical shape by sectional view, the connection apparatus 1 pressurizes the center position of the recessed part 5 with the heating press head 3, as shown in FIG. Thereby, the recessed part 5 is bent symmetrically, the stress applied to the electronic component 11 mounted on the mounting part 12 can be evenly absorbed, and the repulsive force from the buffer material 4 is equally received and the electron is received. The component 13 can be connected.

  Next, an embodiment in which the flexible printed wiring board is anisotropically conductively connected to the other surface of the wiring board on which electronic components such as resistors and fuses are mounted in advance on one surface using the connecting device 1 including the buffer material 4. Will be described as compared with the case of using another connection device.

The wiring board used in the examples and comparative examples is a rigid printed wiring board, and as shown in FIGS.
Resistance a: R1005; Height 0.35mm
Resistance b: R0603; Height 0.23mm
Resistance c: R1608; Height 0.45mm
Fuse d: SFH-0411B; height 1.35 mm
Has been implemented selectively. Each of the resistors a to c has a rated resistance value of 1Ω and a tolerance of ± 5%. As the fuse d, a self-control protector (hereinafter also referred to as “SCP”) manufactured by Sony Chemical & Information Device Co., Ltd. is used, and the heater resistance is 5.5 to 9.1 mΩ.

  Each wiring board has, as a mounting portion, a region where the electronic component having the highest height is mounted among regions on one surface where a plurality of types of electronic components are mounted, and the mounting portion 12 on the other surface opposite to the one surface. A plurality of electrodes are formed across each region on the opposite side to the region adjacent to the mounting portion 12, and the flexible printed wiring board is connected by an anisotropic conductive film, whereby the substrate electrode and the flexible printed wiring board are connected. Conductive connection was made with the electrode. 8 shows a case where an electronic component is also mounted in a region adjacent to the mounting portion, and FIG. 9 shows a case where an electronic component such as a resistor is not mounted in a region adjacent to the mounting portion. FIG. 10 shows a state in which the fuse d (SCP) is mounted on the mounting portion and the resistor b is mounted in the adjacent region.

  In the flexible printed wiring board, a copper pattern is formed on a polyimide substrate, and a gold plating electrode is formed. The anisotropic conductive film uses DP3342MS (manufactured by Sony Chemical & Information Device Co., Ltd.), and the heat and pressure conditions by the connecting device are 2 MPa, 130 ° C., and 6 seconds.

  In the following examples, a connection device in which a cushioning material in which a recess corresponding to the mounting portion was formed was interposed was used. In the comparative example, a connection device that does not include a buffer material, a connection device that includes a buffer material that does not have a recess, and a connection device that includes a buffer material in which a recess is formed are used.

In Example 1, the resistor a was mounted on the mounting portion of the wiring board having a thickness of 12 μm, and the resistor b was mounted in the adjacent region (FIG. 8). The dimensions of the resistors a and b and the cushioning material according to Example 1 are as follows:
Buffer material thickness t1: 5 mm
Height of resistance a in mounting part t2: 0.35 mm
Concave depth d1: 1 mm
Height difference td between the resistance a of the mounting part and the resistance b of the area adjacent to the mounting part: 0.12 mm
(FIG. 8). The buffer material is made of silicone resin, and the rubber hardness (JIS K6253 type A) is 20.

In Example 2, the resistor c is mounted on the mounting portion of the wiring board having a thickness of 12 μm, and no electronic component is mounted in the region adjacent to the mounting portion (FIG. 9). The resistance c and the size of the cushioning material are
Buffer material thickness t1: 5 mm
Height t2 of resistance c in the mounting part: 0.45 mm
Concave depth d1: 1 mm
Height difference td between the resistance c of the mounting part and the area adjacent to the mounting part: 0.45 mm
It is. The buffer material is made of silicone resin, and the rubber hardness (JIS K6253 type A) is 20.

In Example 3, the fuse d was mounted on the mounting portion of the wiring board having a thickness of 12 μm, and the resistor b was mounted in the adjacent region (FIG. 10). The dimensions of the resistor b, fuse d, and cushioning material are:
Buffer material thickness t1: 5 mm
The height t2 of the fuse d in the mounting part: 1.35 mm
Concave depth d1: 1.5 mm
Height difference td between the resistance d of the mounting portion and the resistance b in the region adjacent to the mounting portion: 1.12 mm
It is. The buffer material is made of silicone resin, and the rubber hardness (JIS K6253 type A) is 20.

In Example 4, the resistor a was mounted on the mounting portion of the wiring board having a thickness of 12 μm, and the resistor b was mounted in the adjacent region (FIG. 8). The dimensions of the resistors a and b and the cushioning material according to Example 4 are as follows:
Buffer material thickness t1: 5 mm
Height of resistance a in mounting part t2: 0.35 mm
Concave depth d1: 1 mm
Height difference td between the resistance a of the mounting part and the resistance b of the area adjacent to the mounting part: 0.12 mm
(FIG. 8). The buffer material is made of a silicone resin, and has a rubber hardness (JIS K6253 type A) of 60.

  In Comparative Example 1, a wiring board having a thickness of 18 μm on which no electronic component was mounted was directly placed on a cradle without using a cushioning material, and the flexible printed wiring board was connected by the heating and pressing head 3.

Comparative Example 2 is a flexible printed wiring board in which a 12 μm-thick wiring board in which a resistor a is mounted on a mounting portion and a resistor b is mounted on an adjacent region thereof is directly placed on a cradle, and no cushioning material is used. Were connected by a heating and pressing head 3. The dimensions of resistors a and b are
Height of resistance a in mounting part t2: 0.35 mm
Height difference td between the resistance a of the mounting part and the resistance b of the area adjacent to the mounting part: 0.12 mm
(FIG. 8).

In Comparative Example 3, a 12 μm-thick wiring board in which a resistor a is mounted on a mounting portion and a resistor b is mounted on an adjacent region thereof is directly placed on a cradle, and a cushioning material in which no recess is formed is used. Flexible printed wiring slope was connected. The dimensions of the resistors a and b and the cushioning material are
Buffer material thickness t1: 5 mm
Height of resistance a in mounting part t2: 0.35 mm
Height difference td between the resistance a of the mounting part and the resistance b of the area adjacent to the mounting part: 0.12 mm
(FIG. 8). The buffer material is made of silicone resin, and the rubber hardness (JIS K6253 type A) is 20.

In Comparative Example 4, the resistor c is mounted on the mounting portion of the wiring board having a thickness of 12 μm, and no electronic component is mounted in the region adjacent to the mounting portion (FIG. 9). Moreover, the buffer material in which the recessed part is not formed is used, and the dimension of the resistance c and the buffer material is
Buffer material thickness t1: 5 mm
Height t2 of resistance c in the mounting part: 0.45 mm
Height difference td between the resistance c of the mounting part and the area adjacent to the mounting part: 0.45 mm
It is. The buffer material is made of silicone resin, and the rubber hardness (JIS K6253 type A) is 20.

In Comparative Example 5, the resistor c is mounted on the mounting portion of the wiring board having a thickness of 12 μm, and no electronic component is mounted in the region adjacent to the mounting portion (FIG. 9). Moreover, the buffer material in which the recessed part was formed is used, and the dimension of the resistance c and the buffer material is
Buffer material thickness t1: 5 mm
Height t2 of resistance c in the mounting part: 0.45 mm
Concave depth d1: 1 mm
Height difference td between the resistance c of the mounting part and the area adjacent to the mounting part: 0.45 mm
It is. The buffer material is made of silicone resin and has a rubber hardness (JIS K6253 type A) of 80.

In Comparative Example 6, the fuse d was mounted on the mounting portion of the wiring board having a thickness of 12 μm, and the resistor b was mounted in the adjacent region (FIG. 10). Moreover, using the buffer material in which the concave portion is formed, the dimensions of the fuse d, the resistor b, and the buffer material are:
Buffer material thickness t1: 5 mm
The height t2 of the fuse d in the mounting part: 1.35 mm
Concave depth d1: 1 mm
Height difference td between the fuse d of the mounting part and the resistance b in the region adjacent to the mounting part: 1.12 mm
It is. The buffer material is made of silicone resin, and the rubber hardness (JIS K6253 type A) is 20.

In Comparative Example 7, the fuse d was mounted on the mounting portion of the wiring board having a thickness of 12 μm, and the resistor b was mounted in the adjacent region (FIG. 10). Moreover, using the buffer material in which the concave portion is formed, the dimensions of the fuse d, the resistor b, and the buffer material are:
Buffer material thickness t1: 5 mm
The height t2 of the fuse d in the mounting part: 1.35 mm
Concave depth d1: 4 mm
Height difference td between the fuse d of the mounting part and the resistance b in the region adjacent to the mounting part: 1.12 mm
It is. The buffer material is made of silicone resin, and the rubber hardness (JIS K6253 type A) is 20.

  Under the above conditions, for each example and comparative example, after connecting the flexible printed wiring board, the average resistance value (mΩ) at the connection portion between the electrode provided on the other surface of the wiring board and the electrode of the flexible printed wiring board, and The maximum resistance value (mΩ) was measured. Further, the appearance of resistors a to c previously mounted on one surface of the wiring board, the average rate of change (%) of the resistor, the appearance of fuse d (SCP), and the average value (mΩ) of the heater resistance were measured. The measurement results are shown in Table 1.

  As shown in Table 1, in Examples 1 to 4, a cushioning material having a rubber hardness (JIS K6253 type A) of 20 or 40 is used, and the recess depth d1 is the resistance a, c or fuse d in the mounting portion and the mounting portion. Is the resistance b of the region adjacent to the region or the height difference td of the region (d1 ≧ td), and the thickness (t1-d1) of the main body portion obtained by subtracting the recess depth d1 from the buffer material thickness t1 is The height of the resistor is t2 or more ((t1-d1) ≧ t2). Therefore, in Examples 1 to 4, the average resistance value of the connection portion of each electrode of the rigid printed wiring board and the flexible printed wiring board is suppressed to 88.2 (mΩ) at the maximum, and the maximum resistance value is also 97.1 (mΩ). It can be seen that good connection reliability is maintained without exceeding 100 (mΩ).

  In Examples 1 to 4, there is no abnormality in the appearance of the resistors a to c mounted on one surface of the wiring board in advance, and the average rate of change from the rated resistance value is -0.51% at maximum, with no problem. There was no abnormality in the appearance of the fuse d (SCP), and the average value of the heater resistance was 7.5 (mΩ), and no problem occurred.

  On the other hand, in Comparative Example 1, since the electronic component is not mounted on one surface of the rigid printed wiring board in advance, it is not necessary to use a cushioning material, and the rigid printed wiring board and the flexible printed wiring board exhibit good conduction resistance values. ing.

  Moreover, since the comparative example 2 does not use the buffer material, it is hung according to the height difference of each resistor mounted on the rigid printed wiring board, and is formed on the other surface of the flexible printed wiring board and the rigid printed wiring board. Further, the pressure by the heating and pressing head is applied unevenly to each electrode. As a result, the electrodes of the flexible printed wiring board and the rigid printed wiring board were disconnected, and conduction was not achieved. Moreover, the resistance previously mounted on the rigid printed wiring board was also damaged and could not be conducted.

  Since the comparative example 3 and the comparative example 4 use the buffer material in which the recessed part is not formed, due to the height difference between the resistances a and c in the mounting part and the region adjacent to the mounting part, Excessive stress is applied to the resistors a and c, and the pressure applied by the heating and pressing head is applied unevenly to the electrodes formed on the other surfaces of the flexible printed wiring board and the rigid printed wiring board. As a result, the maximum resistance value at the connection between the rigid printed wiring board and the flexible printed wiring board exceeds 144.8 (mΩ), 139.7 (mΩ), and 100 (mΩ). Connection was not possible and connection reliability was impaired.

  In Comparative Example 5, the hardness of the cushioning material (JIS K6253 type A) was as hard as 80, and the pressure by the heating and pressing head could not be absorbed, so the maximum resistance value at the connection portion between the rigid printed wiring board and the flexible printed wiring board was 140. .5 (mΩ) and exceeding 100 (mΩ), connection reliability was impaired.

  In Comparative Example 6, since the recess depth d1 is shorter than the height difference td between the fuse d in the mounting portion and the resistance b in the region adjacent to the mounting portion, the stress difference due to the height difference td can be absorbed. The maximum resistance value at the connecting portion between the rigid printed wiring board and the flexible printed wiring board was 138.2 (mΩ) exceeding 100 (mΩ), and connection reliability was impaired.

  In Comparative Example 7, since the thickness (t1-d1) of the main body part obtained by subtracting the recess depth d1 from the buffer material thickness t1 is less than the height t2 of the fuse d in the mounting part, the stress applied to the fuse d in the mounting part is Since it was not able to absorb, the maximum resistance value in the connection part of a rigid printed wiring board and a flexible printed wiring board exceeded 130.2 (m (ohm)) and 100 (m (ohm)), and connection reliability was impaired.

DESCRIPTION OF SYMBOLS 1 Connection apparatus, 2 cradle, 3 Heating press head, 4 Buffering material, 4a Flat surface, 4b Other surface, 4c Main part, 5 Recessed part, 10 Wiring board, 11 Electronic component, 12 Mounting part, 13 Electronic component, 17 Different Isotropic conductive adhesive, 23 binder, 24 conductive particles, 25 release film, 26 take-up reel

Claims (5)

A cradle for supporting a substrate on which electronic components are mounted on one surface;
A head for pressurizing a connection member disposed on the other surface of the substrate opposite to the mounting portion on which the electronic component is mounted via an adhesive;
A cushioning material provided on the cradle facing the head and supporting the one side of the substrate;
The cushioning material has a rubber hardness of 60 or less,
The cushioning material is formed of an elastic material, and a surface supporting the one surface is flattened, and a concave portion corresponding to a position where the mounting portion is placed on a surface opposite to the flattened surface Is provided,
The depth d1 of the recess is equal to or greater than a height difference td between the electronic component of the mounting portion and another electronic component that is mounted on the one surface and has a lower height than the electronic component of the mounting portion or a region adjacent to the mounting portion. Yes,
A connection device in which the thickness (t1-d1) of the cushioning material main body obtained by subtracting the depth d1 of the recess from the thickness t1 of the cushioning material is equal to or higher than the height t2 of the electronic component of the mounting part. The connection device according to claim 1, wherein the cushioning material is made of silicone rubber. The connection device according to claim 1, wherein the connection member is an electronic component or a wiring board. Place the one surface of the substrate on which the electronic component is mounted on one surface on a cushioning material provided on the cradle, and adhere to the other surface of the substrate on the opposite side of the mounting portion on which the electronic component is mounted. A step of disposing a connecting member via an agent and pressurizing the connecting member by a head provided to face the buffer material;
The cushioning material has a rubber hardness of 60 or less,
The cushioning material is formed of an elastic material, and a surface that supports the one surface side is flattened, and corresponds to a position where the mounting portion is placed on the surface opposite to the flattened surface. A recess is provided,
The depth d1 of the recess is equal to or greater than a height difference td between the electronic component of the mounting portion and another electronic component that is mounted on the one surface and has a lower height than the electronic component of the mounting portion or a region adjacent to the mounting portion. Yes,
The thickness (t1-d1) of the buffer material main body obtained by subtracting the depth d1 of the recess from the thickness t1 of the buffer material is a method for manufacturing a connection body, which is not less than the height t2 of the electronic component of the mounting part. Place the one surface of the substrate on which the electronic component is mounted on one surface on a cushioning material provided on the cradle, and adhere to the other surface of the substrate on the opposite side of the mounting portion on which the electronic component is mounted. A step of disposing a connecting member via an agent and pressurizing the connecting member by a head provided to face the buffer material;
The cushioning material has a rubber hardness of 60 or less,
The cushioning material is formed of an elastic material, and a surface that supports the one surface side is flattened, and corresponds to a position where the mounting portion is placed on the surface opposite to the flattened surface. A recess is provided,
The depth d1 of the recess is equal to or greater than a height difference td between the electronic component of the mounting portion and another electronic component that is mounted on the one surface and has a lower height than the electronic component of the mounting portion or a region adjacent to the mounting portion. Yes,
The thickness (t1-d1) of the buffer material main body obtained by subtracting the depth d1 of the recess from the thickness t1 of the buffer material is a connection method that is equal to or greater than the height t2 of the electronic component of the mounting part.

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