JP2016031888A - Method for manufacturing anisotropic conductive film and connection structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: a method for manufacturing an anisotropic conductive film capable of achieving both securing of connection reliability between circuit members facing each other and securing of insulation properties between electrodes in a circuit member; and a connection structure.SOLUTION: In an anisotropic conductive film 11, conductive particles P are disposed away from each other along an engraved pattern of a coating roll in a conductive adhesive layer 13. Therefor, conductive particles P, P adjacent each other are prevented from flocculating to each other in connecting circuit members 2, 3, so that insulation properties between bump electrodes 6, 6 and between circuit electrodes 8, 8 can be secured favorably.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for manufacturing an anisotropic conductive film and a connection structure.

  Conventionally, conductive particles are dispersed in an adhesive film, for example, for connection between a liquid crystal display and a tape carrier package (TCP), connection between a flexible printed circuit board (FPC) and TCP, or connection between an FPC and a printed wiring board. An anisotropic conductive film is used. In addition, when a semiconductor silicon chip is mounted on a substrate, so-called chip-on-glass (COG) in which the semiconductor silicon chip is directly mounted on the substrate is used instead of the conventional wire bonding. An adhesive film is used.

  In recent years, with the development of electronic devices, the density of wiring and the functionality of circuits have been advanced. As a result, a connection structure in which the interval between the connection electrodes is, for example, 15 μm or less is required, and the bump electrode of the connection member has also been reduced in area. In order to obtain a stable electrical connection in the bump connection with a reduced area, it is necessary that a sufficient number of conductive particles be interposed between the bump electrode and the circuit electrode on the substrate side.

  In order to deal with such problems, the trapping efficiency of conductive particles is improved by using an anisotropic conductive film in which conductive particles are unevenly distributed on the substrate side in a single layer and the conductive particles are separated from each other (patent) References 1 and 2).

WO2005 / 54388 Japanese Unexamined Patent Publication No. 63-94647

  However, the method described in Patent Document 1 includes a step of spreading conductive particles on an adhesive resin film and a step of biaxially stretching the resin film, and a reduction in the step is desired. Further, in the method described in Patent Document 2, the thickness of the non-conductive matrix material capable of arranging the conductive particles in a single layer is limited.

  The present invention has been made to solve the above problems, and provides a method for producing an anisotropic conductive film capable of dispersing and arranging conductive particles in a single layer at the same time as applying a resin solution. Objective.

  In order to solve the above problems, the method for producing an anisotropic conductive film according to the present invention includes an anisotropic conductive film in which conductive particles and an adhesive component are dissolved in an organic solvent on the surface of a coating roll. A method for producing an anisotropic conductive film comprising an adhesive component, the method comprising supplying the anisotropic conductive film resin solution and scraping off the excess anisotropic conductive film resin solution, and then applying the anisotropic conductive film resin solution. A coating apparatus for applying an anisotropic conductive film resin solution on the surface of a work roll onto a release film is used, and the coating roll peripheral surface portion is a polygonal uneven shape regularly arranged. It has a sculpture process, and has a step of transferring and arranging conductive particles at the same time as applying an adhesive component from a groove of the sculpture onto a release film.

  In the method for producing the anisotropic conductive film of the present invention, when the resin solution is supplied to the coating roll, the conductive particles enter engraving grooves on the unevenness regularly arranged on the peripheral surface portion of the coating roll. For this reason, when apply | coating the anisotropic conductive film resin solution of the coating roll surface on a release film, an electroconductive particle can be arranged similarly to the pattern of a coating roll peripheral surface part. Therefore, it becomes possible to disperse and arrange the conductive particles in a single layer.

Moreover, it is preferable that the polygonal concavo-convex sculpture to be processed on the peripheral surface portion of the coating roll has a regular triangle, square, regular pentagonal shape, or regular hexagonal shape.
In this case, the pattern on the peripheral surface portion of the coating roll can be engraved without any gap, and the conductive particles can be uniformly dispersed and arranged on the release film.

Moreover, it is preferable that the depth of the groove | channel of a polygonal uneven | corrugated shaped engraving is 0.5 to 1.1 times the diameter of a conductive particle.
By satisfying this range, when supplying the resin solution to the coating roll, the conductive particles efficiently enter the groove of the engraving on the peripheral surface portion of the coating roll, and when applying the resin solution to the release film, Conductive particles can be efficiently transferred to a release film.

The coating apparatus includes a coating unit having a sealed chamber for coating the anisotropic conductive film resin solution on the coating roll, and an anisotropic conductive film resin solution in a resin solution reservoir formed in the sealed chamber. It is preferable to provide a resin solution supply means for circulating supply.
By providing the hermetic chamber, solvent volatilization in the resin solution is suppressed, and even when an anisotropic conductive film is applied for a long time, it can be applied with a constant film thickness. Furthermore, it is possible to prevent the conductive particles in the coating solution from being settled by providing the resin solution supply means for circulatingly supplying the resin solution into the resin solution reservoir formed in the sealed chamber.

In addition, the anisotropic conductive film is composed of a conductive adhesive layer composed of an adhesive layer in which conductive particles are dispersed and an insulating layer composed of an adhesive layer laminated on the conductive adhesive layer and in which conductive particles are not dispersed. An adhesive layer.
By adopting such a layer configuration, it is possible to control the adhesion of the anisotropic conductive film, the fluidity during mounting, and the trapping property of the conductive particles trapped between the opposing circuits.

  In addition, the connection structure according to the present invention includes a first circuit member provided with a bump electrode and a second circuit member provided with a circuit electrode corresponding to the bump electrode. It is characterized by being connected via an anisotropic conductive film obtained by a manufacturing method.

  According to this connection structure, in the conductive adhesive layer of the anisotropic conductive film, the conductive particles are dispersed and arranged in a cell pattern engraved on the coating roll. For this reason, in connection of a circuit member, aggregation of the adjacent electrically-conductive particles is suppressed, and the insulation of the electrodes in a circuit member can be ensured favorable. Further, in this connection structure, since the conductive particles are unevenly distributed on one side of the anisotropic conductive film, the fluidity of the conductive particles at the time of pressure bonding is suppressed, and between the electrodes of the opposing circuit members The efficiency of capturing conductive particles can be improved. Therefore, connection reliability between circuit members can be ensured.

  According to the present invention, the resin coating of the anisotropic conductive film and the dispersed arrangement of the conductive particles can be performed in a single step. Moreover, the connection reliability between circuit members and insulation can be made compatible.

It is a mimetic diagram showing one embodiment of a coating device concerning the present invention. It is a typical sectional view showing one embodiment of a coating roll. It is typical sectional drawing which shows one Embodiment of the coating case side transformation part structure. It is explanatory drawing which shows an example of a cell pattern. It is a typical sectional view showing one embodiment of an anisotropic conductive film concerning the present invention. It is explanatory drawing which shows the conductive particle dispersion | distribution state in the anisotropic conductive film which concerns on this invention. It is a typical sectional view showing one embodiment of a connection structure concerning the present invention. It is typical sectional drawing which shows the manufacturing process of the connection structure shown in FIG. FIG. 9 is a schematic cross-sectional view showing a step subsequent to FIG. 8. It is a figure which shows the evaluation test result regarding the dispersibility of the electrically-conductive particle in an anisotropic conductive film. It is a figure which shows the evaluation test result regarding the capture rate and resistance characteristic of the electrically-conductive particle in the connection structure using an anisotropic conductive film.

Hereinafter, a preferred embodiment of a method for producing an anisotropic conductive film according to the present invention will be described in detail with reference to the drawings.
[Coating equipment]

  FIG. 1 shows an embodiment of a coating apparatus according to the present invention. This coating apparatus applies a coating agent to a release film 12 and is disposed in a conveyance path of the release film 12. The upstream guide roll 51 and the downstream guide roll 52 that support the back surface of the release film 12 and the surface of the release film 12 disposed between the upstream guide roll 51 and the downstream guide roll 52. A coating roll 53 for applying the coating agent, and a coating unit 54 for supplying the coating agent to the coating roll 53.

  The conveyance direction is set so that the release film 12 is conveyed substantially vertically between the upstream guide roll 51 and the downstream guide roll 52 from below to above, and both guide rolls 51, 52 are set. A coating roll 53 is disposed between them. With this configuration, while the back surface of the release film 12 is supported by the upstream guide roll 51 and the downstream guide roll 52, the peripheral surface of the coating roll 53 is 0 ° with respect to the surface of the release film 12. Pressure contact is made at a contact angle of -10 °.

  The coating roll 53 is configured to contact the release film 12 and apply a coating agent on the surface while rotating in the direction opposite to the conveying direction of the release film 12. That is, in FIG. 1, when the coating roll 53 is rotationally driven counterclockwise by a driving means (not shown), the contact surface with respect to the release film 12 that moves from below to above moves from above to below. It has become.

  The coating unit 54 includes a coating case 57 provided with a coating agent reservoir 34a having a space opened so as to face the peripheral surface of the coating roll 53, and a front upper end portion of the coating case 57, That is, the doctor blade 58 made of a steel plate or plastic plate attached to the downstream side in the rotation direction of the coating roll 53, and the front lower end of the coating case 57, that is, the coating roll 53 A seal plate 59 made of a steel plate or plastic plate provided on the upstream side in the rotational direction, and a coating agent feeding means 60 for feeding the coating agent into the coating agent reservoir 54a; Is provided.

  The distal end portion of the sealing member composed of the doctor blade 58 and the seal plate 59 is brought into pressure contact with the peripheral surface of the coating roll 53, so that the upper and lower sides of the front surface portion of the coating agent reservoir 54a are above the doctor blade 58 and the seal plate. 59, the coating agent reservoir 54a is hermetically sealed, and excess coating agent adhering to the peripheral surface of the coating roll 53 is rotated according to the rotation of the coating roll 53. It is comprised so that it may be scraped off by.

  As shown in FIG. 1, the coating agent feeding means 60 includes a resin solution tank 61 containing an anisotropic conductive film resin solution in which conductive particles and an adhesive component are dissolved in an organic solvent, and the resin solution tank. A coating agent feeding pipe 63 provided with a feeding pump 62 for sucking the resin solution in 61 and feeding it to the lower part of the coating case 57, and the coating discharged from the upper part of the coating case 57 And a return pipe 64 for returning the resin solution in the agent reservoir 57 to the resin solution tank 61.

  As shown in FIGS. 2 and 3, the coating roll 53 has a roll body 65 made of, for example, a steel pipe material, and rotating shafts 67 provided at both right and left ends of the roll body 65. The peripheral surface of the roll body 65 is composed of a gravure coating roll having a cell layer 68 formed thereon. As shown in FIG. 4, the cell layer 68 has a line-symmetric cell pattern composed of a continuous geometric pattern formed of regular triangular, square, and regular hexagonal cell patterns, that is, the conveyance direction of the base material as a symmetry axis. The left-right symmetrical coating cell pattern 69 is engraved by means such as laser processing.

  A side wall plate 70 is provided at a side end portion of the coating case 57 so as to cover a side end portion of the coating agent reservoir 54 a, and a seal member 71 is attached to the side wall plate 70. In addition, a smooth surface portion 72 on which the coating cell pattern 69 is not engraved is provided at both left and right ends of the peripheral surface of the coating roll 53, and the seal member 71 of the coating case 57 is pressed against the smooth surface portion 72. It has come to be.

  The outer diameter of the coating roll 53 can be set to an arbitrary value, for example, within a range of 30 mm to 200 mm, and is preferably set within a range of 40 mm to 120 mm. By setting the outer diameter of the coating roll 53 to a predetermined value or less, the contact area of the coating roll 53 with respect to the release film 12 can be reduced, and between the coating roll 53 and the release film 12. Since it is possible to suppress the action of a large frictional force, it is possible to effectively suppress the formation of coating unevenness when the resin solution is applied to the release film 12 via the coating roll 53. There are advantages. On the other hand, in the coating apparatus in which the coating roll 53 is long and the distance between the bearings is large and the conveyance speed of the release film 12 is set to be high, the coating roll 53 is bent when the resin solution is applied. Therefore, in order to prevent uneven coating due to this, it is desirable to set the diameter of the coating roll 53 large to some extent.

The depth of the groove of the coating cell pattern 69 is not less than 0.5 times and not more than 1.1 times the diameter of the conductive particles which will be described later. When the depth of the groove is 0.5 times or more the diameter of the conductive particle diameter, the conductive particles are easily arranged in the coating cell pattern. On the other hand, when the depth of the groove is not more than 1.1 times the diameter of the conductive particles, the conductive particles P are also well transferred to the release film 12 when the resin solution is applied to the release film 12. be able to.
[Configuration of anisotropic conductive film]

  The anisotropic conductive film 11 includes a release film 12 and a conductive adhesive layer 13 made of an adhesive layer containing conductive particles P. Further, as shown in the schematic cross-sectional view of FIG. 5, the anisotropic conductive film 11 includes a release film 12, an insulating adhesive layer 14 including an adhesive layer that does not contain the conductive particles P, and conductive particles P. The conductive adhesive layer 13 made of an adhesive layer to be laminated may be laminated in this order. The conductive particles P are dispersed in a state of being unevenly distributed on one surface side of the anisotropic conductive film 11.

  The release film 12 is made of, for example, polyethylene terephthalate (PET), polyethylene, polypropylene, or the like. The release film 12 may contain an arbitrary filler. Further, the surface of the release film 12 may be subjected to a mold release process, a plasma process, or the like.

  The adhesive layer that forms the conductive adhesive layer 13 and the insulating adhesive layer 14 contains, for example, a curing agent, a monomer, and a film forming material. When an epoxy resin monomer is used, examples of the curing agent include imidazole series, hydrazide series, boron trifluoride-amine complex, sulfonium salt, amine imide, polyamine salt, dicyandiamide, and the like. It is preferable to coat the curing agent with a polyurethane-based or polyester-based polymer substance to form a microcapsule because the pot life is extended. On the other hand, when an acrylic monomer is used, examples of the curing agent include those that decompose by heating such as peroxide compounds and azo compounds to generate free radicals.

  The curing agent when an epoxy monomer is used is appropriately selected depending on the intended connection temperature, connection time, storage stability, and the like. From the viewpoint of high reactivity, the curing agent preferably has a gel time with the epoxy resin composition of 10 seconds or less at a predetermined temperature. From the viewpoint of storage stability, the epoxy is cured after storage in a thermostatic bath at 40 ° C. for 10 days. A sulfonium salt that does not change in gel time with the resin composition is preferable.

  The curing agent when an acrylic monomer is used is appropriately selected depending on the intended connection temperature, connection time, storage stability, and the like. From the viewpoint of high reactivity and storage stability, an organic peroxide or an azo compound having a half-life of 10 hours at a temperature of 40 ° C. or more and a half-life of 1 minute at a temperature of 180 ° C. or less is preferred. Is more preferably an organic peroxide or azo compound having a temperature of 60 ° C. or more and a half-life of 1 minute of 170 ° C. or less. These curing agents can be used alone or as a mixture thereof, and may be used by mixing a decomposition accelerator, an inhibitor and the like.

  In either case of using an epoxy monomer and an acrylic monomer, in order to obtain a sufficient reaction rate when the connection time is 10 seconds or less, the blending amount of the curing agent is the monomer described later and the film forming material described later. It is preferable to set it as 0.1 mass part-40 mass parts with respect to a total of 100 mass parts, and it is more preferable to set it as 1 mass part-35 mass parts. By setting the blending amount of the curing agent to 0.1 parts by mass or more, a sufficient reaction rate can be obtained, and it becomes easy to realize good adhesive strength and low connection resistance. On the other hand, it becomes easy to implement | achieve favorable fluidity | liquidity of an adhesive agent, the storage stability of an adhesive agent, and favorable connection resistance because the compounding quantity of a hardening | curing agent shall be 40 mass parts or less.

  In addition, when an epoxy resin monomer is used as a monomer, bisphenol type epoxy resin derived from epichlorohydrin and bisphenol A, bisphenol F, bisphenol AD, etc., epoxy novolac resin or glycidyl derived from epichlorohydrin and phenol novolac or cresol novolac Various epoxy compounds having two or more glycidyl groups in one molecule such as amine, glycidyl ether, biphenyl, and alicyclic can be used. These may be used individually by 1 type, and 2 or more types may be mixed and used for them.

  When an acrylic monomer is used, the radical polymerizable compound is preferably a substance having a functional group that is polymerized by radicals. Examples of such radically polymerizable compounds include (meth) acrylates, maleimide compounds, styrene derivatives, and the like. These may be used individually by 1 type, and 2 or more types may be mixed and used for them. Moreover, the radically polymerizable compound can be used in any state of a monomer or an oligomer, and a monomer and an oligomer may be mixed and used.

  The film forming material facilitates the handling of a liquid composition containing the above curing agent and monomer. As the film forming material, a thermoplastic resin is preferably used, and examples thereof include phenoxy resin, polyvinyl formal resin, polystyrene resin, polyvinyl butyral resin, polyester resin, polyacrylic resin, and polyester urethane resin. Furthermore, these polymers may contain siloxane bonds or fluorine substituents. These resins can be used alone or in admixture of two or more. Among the above resins, a phenoxy resin is preferably used from the viewpoints of adhesive strength, compatibility, heat resistance, and mechanical strength.

  The larger the molecular weight of the thermoplastic resin, the easier it is to form the film, and the melt viscosity that affects the fluidity of the anisotropic conductive film can be set in a wide range. The molecular weight of the thermoplastic resin is preferably 5000 to 150,000 in weight average molecular weight, and particularly preferably 10,000 to 80,000. When the weight average molecular weight is 5000 or more, good film formability is easily obtained, and when it is 150,000 or less, good compatibility with other components is easily obtained.

  In addition, in this invention, a weight average molecular weight means the value measured using the calibration curve by a standard polystyrene from a gel permeation chromatograph (GPC) according to the following conditions. (Measurement conditions) Device: GPC-8020 manufactured by Tosoh Corporation RI-8020 manufactured by Tosoh Corporation Column: Gelpack GLA160S + GLA150S manufactured by Hitachi Chemical Co., Ltd. Sample concentration: 120 mg / 3 mL Solvent: Tetrahydrofuran Injection amount: 60 μL Pressure: 2.94 × 106 Pa (30 kgf / cm2) Flow rate: 1.00 mL / min

  Further, the content of the film forming material is preferably 5% by weight to 80% by weight, and more preferably 15% by weight to 70% by weight, based on the total amount of the monomer and the film forming material. When it is 5% by weight or more, good film formability is easily obtained, and when it is 80% by weight or less, the curable composition tends to exhibit good fluidity.

  The adhesive layer that forms the conductive adhesive layer 13 and the insulating adhesive layer 14 includes a filler, a softener, an accelerator, an anti-aging agent, a colorant, a flame retardant, a thixotropic agent, and a coupling. An agent, a phenol resin, a melamine resin, isocyanates and the like may be further contained. When the filler is contained, further improvement in connection reliability can be expected.

  Examples of the conductive particles P include metal particles such as gold, silver, nickel, copper, and solder, or carbon particles. In order to obtain the storage stability of the conductive particles P, the surface layer of the conductive particles P is preferably not a transition metal such as copper but a noble metal such as gold or silver, and among these, gold is more preferable. preferable. Further, the nickel surface may be coated with a noble metal such as Au. Further, a non-conductive glass, ceramic, plastic, or the like coated with a conductive material such as the above metal may be used. In this case, a nickel layer may be provided to form a multilayer structure.

  In addition, when the conductive particle P is a non-conductive plastic coated with a conductive material or a hot-melt metal particle, the conductive particle P is easily deformed by heating and pressurization. The contact area is increased, and variations in thickness on the circuit member side can be absorbed to improve connection reliability. Further, the connection resistance can be lowered by providing protrusions on the surface of the conductive particles P.

  The average particle size of the conductive particles P is preferably 2.5 μm or more and 6.0 μm or less. By setting the average particle size of the conductive particles P to 2.5 μm or more, the coating accuracy on the release film 12 is maintained, and the conductive particles P are easily dispersed well in the conductive adhesive layer 13. By setting the average particle size of the conductive particles P to 6.0 μm or less, it becomes easy to maintain the insulation between the adjacent circuit electrodes 8 and 8 of the connection structure 1. In order to obtain good dispersibility of the conductive particles P, the average particle size of the conductive particles P is more preferably 2.7 μm or more, and further preferably 3 μm or more. On the other hand, from the viewpoint of ensuring insulation between the adjacent circuit electrodes 8 and 8 of the connection structure 1, the average particle size of the conductive particles P is more preferably 5.5 μm or less, and is preferably 5 μm or less. Is more preferable.

  The average particle diameter of the conductive particles P is obtained by measuring the particle diameter of any 300 conductive particles by observation using a scanning electron microscope (SEM) and taking the average value thereof. When the conductive particles P have protrusions or are not spherical, the particle size of the conductive particles P is the diameter of a circle circumscribing the conductive particles in the SEM image.

The blending amount of the conductive particles P is preferably 1 to 100 parts by volume with respect to 100 parts by volume of components other than the conductive particles P. From the viewpoint of suitably achieving both the dispersibility of the conductive particles P and the insulation between adjacent circuits during mounting, the blending amount of the conductive particles P is more preferably 10 to 50 parts by volume. Furthermore, in the range where the average particle diameter of the conductive particles is 2.5 μm or more and 6.0 μm or less, the particle density of the conductive particles is preferably 5000 / mm ² or more and 50000 / mm ² or less.

  The thicknesses of the conductive adhesive layer 13 and the insulating adhesive layer 14 can be set as appropriate. The total thickness of the conductive adhesive layer 13 and the insulating adhesive layer 14 is, for example, 5 μm to 30 μm, and it is desirable to adjust the timely according to the electrode height of the connection structure to be manufactured. The height is preferably 1.0 times or more and less than 1.2 times the height. In the case of 1.0 times or less, the connection structure may not be filled with the anisotropic conductive film, and the adhesiveness and the insulation are deteriorated. On the other hand, when the total thickness of the conductive adhesive layer 13 and the insulating adhesive layer 14 is 1.2 times or more, the anisotropic conductive film protrudes in a large amount from the connection structure, and the mounting tact deteriorates. There arises a problem that a deviation from a desired mounting position becomes large.

Regarding the thickness of the insulating adhesive layer 14 and the conductive adhesive layer 13 constituting the anisotropic conductive film 11 and the position where the conductive particles P in the anisotropic conductive film 11 exist, for example, a focused ion beam ( The cross section of the anisotropic conductive film 11 can be cut using FIB), and then observed and measured with a scanning electron microscope (SEM). Specifically, the release film 12 side of the anisotropic conductive film 11 is fixed to a jig for sample processing / observation using a conductive carbon tape. Thereafter, a platinum sputtering process is performed from the conductive adhesive layer 13 side to form a 20 nm platinum film on the conductive adhesive layer 13. Next, processing is performed from the side of the conductive adhesive layer 13 of the anisotropic conductive film 11 using a focused ion beam (FIB), and the processed cross section is observed with a scanning electron microscope (SEM).
[Method of manufacturing anisotropic conductive film]

The anisotropic conductive film 11 is manufactured as follows. The release film 12 conveys the long release film 12 substantially vertically from the lower side to the upper side between the upstream guide roll 51 and the downstream guide roll 52.
On the conveyance path of the release film 12, a coating roll 53 for applying a resin solution that is a material for forming the conductive adhesive layer 13 is disposed, and the resin solution in which the conductive particles P are dispersed by the coating roll 53. Is applied onto the release film 12. At this time, the conductive particles P are arranged in the pattern of the cell pattern 69 engraved on the cell layer 68 on the coating roll 53.

  The viscosity of the resin solution can be varied depending on the application and application method, but it is usually preferable to set the viscosity to 1 mPa · s to 10000 mPa · s. From the viewpoint of suppressing separation of the compound in the resin solution and improving compatibility, it is more preferably 10 mPa · s to 1000 mPa · s. Moreover, it is preferable to set it as 20 mPa * s-300 mPa * s for the external appearance improvement of the anisotropic conductive film 11 on the characteristic of a coating system. When it exceeds 10,000 mPa · s, it becomes difficult not only to supply the resin solution to the coating roll 53 but also to scrape off the excess amount of the supplied resin solution with the doctor blade 58. Moreover, if it is less than 1 mPa · s, there is a possibility that the composition of the adhesive paste W may be separated.

  In addition, it is preferable that the drying temperature of a resin solution is 20 to 80 degreeC, for example. Moreover, it is preferable that the conveyance speed of the peeling film 12 is 30 mm / s-160 mm / s, for example. The thickness of the adhesive paste W is preferably 5 μm to 10 μm, for example, when using conductive particles P having an average particle diameter of 3 μm.

After the formation of the conductive adhesive layer 13, a separately prepared insulating adhesive layer 14 may be laminated on the conductive adhesive layer 13. Thereby, the anisotropic conductive film 11 shown in FIG. 5 is obtained. For example, a hot roll laminator can be used for laminating the insulating adhesive layer 14. Further, the present invention is not limited to laminating, and an adhesive paste as a material for the insulating adhesive layer 14 may be applied and dried on the conductive adhesive layer 13.
[Method of manufacturing connection structure]

  FIG. 8 is a schematic cross-sectional view showing a manufacturing process of the connection structure shown in FIG. In forming the connection structure 1, first, the release film 12 is peeled from the anisotropic conductive film 11, and the anisotropic conductive film 11 is secondly attached such that the conductive adhesive layer 13 side faces the mounting surface 7 a. Is laminated on the circuit member 3. Next, as shown in FIG. 9, the first circuit member 2 is disposed on the second circuit member 3 laminated with the anisotropic conductive film 11 so that the bump electrode 6 and the circuit electrode 8 face each other. To do. Then, the first circuit member 2 and the second circuit member 3 are pressed in the thickness direction while heating the anisotropic conductive film 11.

  Thereby, the adhesive component of the anisotropic conductive film 11 flows, the conductive adhesive layer and the insulating adhesive layer are in a state where the distance between the bump electrode 6 and the circuit electrode 8 is reduced and the conductive particles P are engaged. 14 is cured. By the curing of the conductive adhesive layer and the insulating adhesive layer 14, the bump electrode 6 and the circuit electrode 8 are electrically connected, and the adjacent bump electrodes 6 and 6 and the adjacent circuit electrodes 8 and 8 are connected to each other. A cured product 4 of the anisotropic conductive film is formed in an electrically insulated state, and the connection structure 1 shown in FIG. 1 is obtained. In the obtained connection structure 1, the cured product 4 of the anisotropic conductive film sufficiently prevents the change in the distance between the bump electrode 6 and the circuit electrode 8 over time, and the long-term reliability of the electrical characteristics. Can also be secured.

  The heating temperature of the anisotropic conductive film 11 is preferably equal to or higher than a temperature at which polymerization active species are generated in the curing agent and polymerization of the polymerization monomer is started. This heating temperature is, for example, 80 ° C. to 200 ° C., preferably 100 ° C. to 180 ° C. The heating time is, for example, 0.1 second to 30 seconds, preferably 1 second to 20 seconds. When the heating temperature is less than 80 ° C., the curing rate is slow, and when it exceeds 200 ° C., unwanted side reactions tend to proceed. Further, if the heating time is less than 0.1 seconds, the curing reaction does not proceed sufficiently, and if it exceeds 30 seconds, the productivity of the cured product is lowered, and further unwanted side reactions are likely to proceed.

  As described above, in the method for manufacturing the anisotropic conductive film 11 according to the present invention, the conductive particles P can be dispersed and arranged in the cell pattern of the coating roll in the anisotropic conductive film 11. Moreover, the connection structure using the anisotropic conductive film 11 according to the present invention can achieve both connection reliability and insulation.

Examples of the present invention and comparative examples will be described below.
Example 1

  45 g of 4,4 ′-(9-fluorenylidene) -diphenol (manufactured by Sigma-Aldrich Japan Co., Ltd.) and 50 g of 3,3 ′, 5,5′-tetramethylbiphenol diglycidyl ether (manufactured by Mitsubishi Chemical Corporation: YX- 4000 H) was dissolved in 1000 mL of N-methylpyrrolidone in a 3000 mL three-necked flask equipped with a Dimroth condenser tube, a calcium chloride tube, and a Teflon stirring rod (Teflon is a registered trademark) connected to a stirring motor. It was. To this, 21 g of potassium carbonate was added and stirred while heating to 110 ° C. with a mantle heater. After stirring for 3 hours, the reaction solution was dropped into a beaker containing 1000 mL of methanol, and the produced precipitate was collected by suction filtration. The precipitate collected by filtration was further washed three times with 300 mL of methanol to obtain 75 g of phenoxy resin a.

  Thereafter, the molecular weight of the phenoxy resin a was measured using a high performance liquid chromatograph GP8020 manufactured by Tosoh Corporation (column: Gelpak GLA150S and GLA160S manufactured by Hitachi Chemical Co., Ltd., solvent: tetrahydrofuran, flow rate: 1.0 mL / min). As a result, Mn = 15769, Mw = 38045, and Mw / Mn = 2.413 in terms of polystyrene.

  Next, in forming a resin solution for the conductive adhesive layer, 50 parts by mass of bisphenol A type epoxy resin (Mitsubishi Chemical Corporation: jER828) as the epoxy compound and 4-hydroxyphenylmethylbenzyl as the curing agent are used. 5 parts by mass of sulfonium hexafluoroantimonate in a solid content and 50 parts by mass of a phenoxy resin a as a film forming material in a solid content were blended. Further, regarding the conductive particles, a nickel layer having a thickness of 0.2 μm is provided on the surface of particles having polystyrene as a core, and conductive particles having an average particle diameter of 3 μm and a specific gravity of 2.5 are produced. It mix | blended with the resin composition. Then, it was applied to a PET resin film having a thickness of 50 μm using a coating roll having a regular hexagonal sculpture having a side of 4.6 μm and a depth of 3 μm, and the resin composition was dried with hot air at 70 ° C. for 5 minutes, A conductive adhesive layer having a thickness of 3 μm was obtained.

Next, in forming an adhesive paste for an insulating adhesive layer, 45 parts by mass of bisphenol F type epoxy resin (Mitsubishi Chemical Corporation: jER807) as an epoxy compound and 4-hydroxyphenylmethyl as a curing agent are used. 5 parts by mass of benzylsulfonium hexafluoroantimonate in a solid content, and 55 parts by mass of a phenoxy resin b having an Mw of 50000 · Tg of 70 ° C. as a film forming material were blended. And it apply | coated to the 50-micrometer-thick PET resin film using a coater, and the hot-air drying was performed for 5 minutes at 70 degreeC, and the insulating adhesive layer with a thickness of 16 micrometers was obtained. Thereafter, the conductive adhesive layer and the insulating adhesive layer were heated to 40 ° C. and bonded with a hot roll laminator to obtain an anisotropic conductive film according to Example 1.
(Example 2)

An anisotropic conductive film according to Example 2 was produced in the same manner as in Example 1 except that a coating roll having a square sculpture having a side of 5.3 μm and a depth of 3 μm was used.
(Example 3)

An anisotropic conductive film according to Example 3 was produced in the same manner as in Example 1 except that a coating roll having an equilateral triangle sculpture having a side of 5.7 μm and a depth of 3 μm was used.
(Comparative Example 1)
An anisotropic conductive film according to Comparative Example 1 was produced in the same manner as in Example 1 except that a coating roll having a linear engraving with an interval of 5 μm and a depth of 3 μm was used.
(Density calculation of conductive particles in anisotropic conductive film)

For the anisotropic conductive films of Examples 1 to 3 and Comparative Example 1, the number of conductive particles per 2500 μm ² (50 μm × 50 μm) was measured with a metallographic microscope at 20 locations, and the average value was converted to 1 mm ² . .
(Evaluation of monodispersity of conductive particles)

For the anisotropic conductive films of Examples 1 to 3 and Comparative Example 1, the monodispersion rate of the conductive particles (the ratio at which the conductive particles are separated from other adjacent conductive particles (monodispersed state)) evaluated. Monodispersion ratio, the monodispersion ratio (%) = (2500μm ² in conductive particle number monodisperse / 2500 [mu] m conductive particle count in ²⁾ × 100, it is determined using. The actual measurement of the conductive particles was performed at a magnification of 200 times using a metal microscope.

FIG. 10 is a diagram showing the evaluation experiment results. As shown in the figure, the anisotropic conductive films according to Examples 1 to 3 and Comparative Example 1 all have a conductive particle density of 30000 ± 2000 particles / mm ² . However, the monodispersity of Comparative Example 1 is 40%, whereas the monodispersities of Examples 1 to 3 exceed 70%, and good monodispersity is obtained.
(Production of connection structure)

  As a first circuit member, an IC chip having a straight arrangement structure in which bump electrodes are arranged in a row (outer dimensions 2 mm × 20 mm, thickness 0.55 mm, bump electrode size 100 μm × 30 μm, distance between bump electrodes 8 μm, bump electrode thickness 15 μm) was prepared. As the second circuit member, an ITO wiring pattern (pattern width 21 μm, interelectrode space 17 μm) formed on the surface of a glass substrate (Corning Inc .: # 1737, 38 mm × 28 mm, thickness 0.3 mm) is used. Got ready.

For the connection between the IC chip and the glass substrate, a thermocompression bonding apparatus composed of a stage (150 mm × 150 mm) composed of a ceramic heater and a tool (3 mm × 20 mm) was used. First, the release film on the conductive adhesive layer of the anisotropic conductive film (2.5 mm × 25 mm) according to Examples 1 to 3 and Comparative Example 1 was peeled off, and the surface on the conductive adhesive layer side was a glass substrate. The film was attached by heating and pressing for 2 seconds at 80 ° C. and 0.98 MPa (10 kgf / cm ² ).

Next, after peeling off the release film on the insulating adhesive layer of the anisotropic conductive film and aligning the bump electrode of the IC chip with the circuit electrode of the glass substrate, the actual measurement of the anisotropic conductive film The insulating adhesive layer was attached to the IC chip by heating and pressurizing for 5 seconds under the conditions of an ultimate temperature of 170 ° C. and an area-converted pressure of 70 MPa at the bump electrode.
(Evaluation of capture rate and resistance characteristics of conductive particles)

  In the connection structure obtained by using each anisotropic conductive film of Examples 1 to 3 and Comparative Example 1, the capture rate of conductive particles between the bump electrode and the circuit electrode, between the bump electrode and the circuit electrode And the insulation resistance between adjacent circuit electrodes were evaluated. The capture rate is a ratio of the density of the conductive particles on the bump electrode to the density of the conductive particles in the anisotropic conductive film, and the capture rate (%) = (average of the number of conductive particles on the bump electrode / (bump electrode area) X number of conductive particles per unit area of anisotropic conductive film)) x 100

Moreover, evaluation of resistance value was implemented by the four-terminal measuring method, and the average value of the measurement of 14 places was used. In the evaluation of the insulation resistance, a voltage of 50 V was applied to the connection structures obtained using the anisotropic conductive films of Examples 1 to 3 and Comparative Example 1, and the insulation resistance between a total of 1440 circuit electrodes. Were measured together. As for the insulation resistance, a case where it was greater than 10 ⁸ Ω was judged as A, and a case where it was 10 ⁸ Ω or less was judged as B.

  FIG. 11 is a diagram showing the evaluation experiment results. As shown in the figure, in each of the connection structures according to Examples 1 to 3 and Comparative Example 1, the capturing rate of the conductive particles was around 50%, and the resistance value was good. On the other hand, the insulation test evaluation of the connection structure according to Examples 1 to 3 is A determination, but the insulation test evaluation of the connection structure according to Comparative Example 1 is B determination, which is lower than that of Examples 1 to 3. did.

  DESCRIPTION OF SYMBOLS 1 ... Connection structure, 2 ... 1st circuit member, 3 ... 2nd circuit member, 4 ... Hardened | cured material of anisotropic conductive film, 5 ... Main part of 1st circuit member, 6 ... Bump electrode, 7 The main body of the second circuit member, 8 the circuit electrode, 11 the anisotropic conductive film, 12 the release film, 13 the conductive adhesive layer, 14 the insulating adhesive layer, and P conductive particles.

Claims (6)

A method for producing an anisotropic conductive film comprising conductive particles and an adhesive component,
The anisotropic conductive film was supplied to the surface of the coating roll with an anisotropic conductive film resin solution in which conductive particles and adhesive components were dissolved in an organic solvent, and the excess anisotropic conductive film resin solution was scraped off. Later, using a coating device that applies the anisotropic conductive film resin solution on the surface of the coating roll on the release film,
The coating roll peripheral surface portion has polygonal irregularities engraved regularly arranged regularly,
A method for producing an anisotropic conductive film, comprising: applying an adhesive component from a groove of the engraving to a release film and simultaneously transferring and arranging conductive particles.   2. The method for producing an anisotropic conductive film according to claim 1, wherein the polygonal concavo-convex sculpture is a regular triangle, a square, a regular pentagonal shape, or a regular hexagonal shape.   3. The anisotropic conductive according to claim 1, wherein a depth of the groove of the polygonal concavo-convex sculpture is not less than 0.5 times and not more than 1.1 times the diameter of the conductive particles. For producing a conductive film.   The coating device includes a coating unit having a sealed chamber for coating the coating roll with an anisotropic conductive film resin solution, and an anisotropic conductive film resin solution in a resin solution reservoir formed in the sealed chamber. A method for producing an anisotropic conductive film according to any one of claims 1 to 3, further comprising a resin solution supply means for circulating supply.   The anisotropic conductive film includes a conductive adhesive layer composed of an adhesive layer in which the conductive particles are dispersed, and an adhesive layer laminated on the conductive adhesive layer and in which the conductive particles are not dispersed. The manufacturing method of the anisotropic conductive film as described in any one of Claims 1-5 provided with the insulating adhesive bond layer which becomes.   The anisotropic conductivity according to any one of claims 1 to 5, wherein a first circuit member provided with a bump electrode and a second circuit member provided with a circuit electrode corresponding to the bump electrode are used. A connection structure characterized by being connected via an anisotropic conductive film obtained by a film manufacturing method.

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