JP6705516B2 - Method for producing anisotropically conductive film - Google Patents

Description

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

Conventionally, for example, for connecting a liquid crystal display to a tape carrier package (TCP), connecting a flexible printed circuit board (FPC) to TCP, or connecting an FPC to a printed wiring board, conductive particles are dispersed in an adhesive film. The anisotropic conductive film is used. Also, when mounting a semiconductor silicon chip on a substrate, so-called chip-on-glass (COG), which mounts the semiconductor silicon chip directly on the substrate, is performed instead of the conventional wire bonding, and anisotropic conductivity is also used here. Film is used.

2. Description of the Related Art In recent years, with the development of electronic devices, wiring density and circuit functionality have been increasing. As a result, a connection structure is required in which the distance between the connection electrodes is, for example, 15 μm or less, and the bump electrodes of the connection members are also reduced in area. In order to obtain stable electrical connection in bump connection with a reduced area, a sufficient number of conductive particles must be present between the bump electrode and the circuit electrode on the substrate side.

For such a problem, the conductive particles are unevenly distributed on the substrate side in a single layer, and the anisotropic conductive film in which the conductive particles are separated from each other is used to improve the capturing efficiency of the conductive particles (Patent Document 1). References 1 and 2).

WO2005/54388 JP-A-63-94647

However, the method described in Patent Document 1 includes a step of spreading conductive particles on a resin film having adhesiveness and a step of biaxially stretching the resin film, and it is desired to shorten the step. 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 anisotropically conductive film in which conductive particles can be dispersed and arranged in a single layer while coating a resin solution. To aim.

In order to solve the above problems, the method for producing an anisotropic conductive film according to the present invention, the conductive particles and the film is an anisotropic conductive adhesive in which the conductive particles and the adhesive component are dissolved in an organic solvent on the surface of the coating roll. A method for producing an anisotropic conductive film containing an agent component, comprising supplying the anisotropic conductive film resin solution and scraping off the excess anisotropic conductive film resin solution, and then applying a coating roll. Characterized by using a coating device for coating the anisotropic conductive film resin solution of the surface of the release film, the coating roll peripheral surface portion is a regularly arranged polygonal concave-convex engraving process. It has a step of applying the adhesive component from the groove of the engraving onto the release film, and at the same time transferring and arranging the conductive particles.

In the method for producing an anisotropic conductive film of the present invention, when the resin solution is supplied to the coating roll, the conductive particles enter the engraved grooves on the irregularities regularly arranged on the peripheral surface of the coating roll. Therefore, when the anisotropic conductive film resin solution on the surface of the coating roll is applied onto the release film, the conductive particles can be arranged in the same manner as the pattern of the peripheral surface of the coating roll. Therefore, it becomes possible to disperse and arrange the conductive particles in a single layer.

In addition, it is preferable that the polygonal concave-convex engraving to be processed on the peripheral surface of the coating roll is a regular triangle, a square, a regular pentagon, or a regular hexagon. In this case, the pattern on the peripheral surface of the coating roll can be engraved without any gap, and the conductive particles can be uniformly dispersed and arranged on the release film.

Further, it is preferable that the depth of the groove of the polygonal concave-convex engraving is 0.5 times or more and 1.1 times or less the diameter of the conductive particles. 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 of the coating roll, and when applying the resin solution to the release film, the conductive film is electrically conductive. The particles can be efficiently transferred to the release film.

Further, the coating device, a coating unit having a closed chamber for applying the anisotropic conductive film resin solution to the coating roll, and the anisotropic conductive film resin solution in the resin solution reservoir formed in the closed chamber. It is preferable to provide a resin solution supply means for circulating supply. By providing the closed chamber, it is possible to suppress the solvent volatilization in the resin solution and to apply the anisotropic conductive film with a constant film thickness even in the case of long-length application. Further, by providing a resin solution supply means for circulating and supplying the resin solution into the resin solution reservoir formed in the closed chamber, it is possible to prevent the conductive particles in the coating solution from settling.

Further, the anisotropic conductive film is an insulating layer composed of an adhesive layer in which conductive particles are dispersed, and an adhesive layer in which conductive particles are not dispersed and which is laminated on the conductive adhesive layer. And a conductive adhesive layer. With such a layer structure, it is possible to control the adhesiveness of the anisotropic conductive film, the fluidity at the time of mounting, and the catching property of the conductive particles trapped between the opposed circuits.

Further, the connection structure according to the present invention comprises a first circuit member provided with bump electrodes and a second circuit member provided with circuit electrodes corresponding to the bump electrodes, the anisotropic conductive film It is characterized in that they are 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 a coating roll. Therefore, when connecting the circuit members, the agglomeration of adjacent conductive particles can be suppressed, and good insulation between the electrodes in the circuit member can be ensured. 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 circuit members facing each other. The efficiency of capturing conductive particles can be improved. Therefore, the connection reliability between the circuit members can be secured.

According to the present invention, the application of the resin for the anisotropic conductive film and the dispersed arrangement of the conductive particles can be performed in a single step. Further, it is possible to achieve both the connection reliability and the insulation property between the circuit members.

It is a schematic diagram which shows one Embodiment of the coating device which concerns on this invention. It is a typical sectional view showing one embodiment of a coating roll. It is a typical sectional view showing one embodiment of a coating case side change part structure. It is explanatory drawing which shows an example of a cell pattern. It is a typical sectional view showing one embodiment of the anisotropic conductive film concerning the present invention. It is explanatory drawing which shows the electrically conductive particle dispersion state in the anisotropically conductive film which concerns on this invention. It is a typical sectional view showing one embodiment of a connection structure concerning the present invention. FIG. 8 is a schematic cross-sectional view showing a manufacturing process of the connection structure shown in FIG. 7. FIG. 9 is a schematic cross-sectional view showing a step subsequent to that of FIG. 8. It is a figure which shows the evaluation test result regarding the dispersibility of the electroconductive particle in an anisotropically conductive film. It is a figure which shows the evaluation test result regarding the capture rate of a conductive particle in a connection structure using an anisotropically conductive film, and a resistance characteristic.

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

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 provided in a conveying path of the release film 12. An upstream guide roll 51 and a downstream guide roll 52 that support the back surface of the release film 12, and a coating agent that is disposed between the upstream guide roll 51 and the downstream guide roll 52 and is applied to the surface of the release film 12. And a coating unit 54 for supplying a coating agent to the coating roll 53.

The transport direction is set so that the release film 12 is transported substantially vertically from below to above between the upstream guide roll 51 and the downstream guide roll 52, and at the same time, A coating roll 53 is arranged 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° to 10° with respect to the surface of the release film 12. It is designed to be pressed at a contact angle of °.

Further, the coating roll 53 is configured to contact the release film 12 and apply the coating agent to the surface thereof 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 in the counterclockwise direction by a driving unit (not shown), the contact surface with respect to the peeling film 12 moving from below to above is moved from above to below. Is becoming

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

The tip end of the seal member including the doctor blade 58 and the seal plate 59 is pressed against the peripheral surface of the coating roll 53, so that the upper and lower portions of the front surface of the coating agent reservoir 54a are the doctor blade 58 and the seal plate. The coating material reservoir 54a is sealed by 59 so that the coating material reservoir 54a is in a hermetically sealed state, and the excess coating material attached to the peripheral surface of the doctor blade 58 is attached to the doctor blade 58 according to the rotation of the coating roll 53. It is configured to be scraped off by.

As shown in FIG. 1, the coating material 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. Coating agent feeding pipe 63 provided with a feeding pump 62 for sucking the resin solution in 61 and feeding it to the lower portion of the coating case 57, and coating discharged from the upper portion of the coating case 57. A return pipe 64 for returning the resin solution in the agent reservoir 57 to the resin solution tank 61 is provided.

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 left and right ends of the roll body 65. A gravure coating roll having a cell layer 68 formed on the peripheral surface of the roll body 65 is formed. As shown in FIG. 4, the cell layer 68 has a line-symmetrical cell pattern composed of a continuous geometrical pattern composed of equilateral triangular, square, or regular hexagonal cell patterns, that is, the base material carrying direction is the axis of symmetry. The left-right symmetrical coating cell pattern 69 is engraved by means such as laser processing.

A side wall plate 70 that covers the side end of the coating agent reservoir 54a is provided at the side end of the coating case 57, and a seal member 71 is attached to the side wall 70. Further, smooth surface portions 72 on which the coating cell pattern 69 is not stamped are provided at both left and right peripheral surfaces of the coating roll 53, and the sealing members 71 of the coating case 57 are pressed against the smooth surface portions 72. It is supposed to be done.

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 preferably 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 the release film 12 can be reduced, and a large friction occurs between the coating roll 53 and the release film 12. Since it is possible to suppress the action of force, there is an advantage that 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. .. On the other hand, in the coating device 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 a high speed, the coating roll 53 is not bent when the resin solution is applied. Since it tends to occur, it is desirable to set the diameter of the coating roll 53 to some extent large in order to prevent coating unevenness due to this.

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 particle P described later. When the depth of the groove is 0.5 times or more the diameter of the conductive particles, the conductive particles are easily arranged in the coating cell pattern. On the other hand, when the depth of the groove is 1.1 times or less of the diameter of the conductive particles, the conductive particles P may be satisfactorily transferred to the release film 12 when the resin solution is applied to the release film 12. it can.
[Structure of anisotropic conductive film]

The anisotropic conductive film 11 includes a release film 12 and a conductive adhesive layer 13 formed 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 contains a release film 12, an insulating adhesive layer 14 made of an adhesive layer containing no conductive particles P, and conductive particles P. The conductive adhesive layer 13 made of an adhesive layer may be laminated in this order. As shown in FIG. 6, the conductive particles P are dispersed while 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 any filler. Further, the surface of the release film 12 may be subjected to release treatment, plasma treatment, or the like.

The adhesive layers forming the conductive adhesive layer 13 and the insulating adhesive layer 14 contain, 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-based, hydrazide-based, boron trifluoride-amine complex, sulfonium salts, amine imides, polyamine salts, and dicyandiamide. It is preferable to coat the curing agent with a polyurethane-based or polyester-based polymer substance or the like to form microcapsules, because the pot life is extended. On the other hand, when an acrylic monomer is used, examples of the curing agent include peroxide compounds, azo compounds, and the like that decompose by heating to generate free radicals.

The curing agent in the case of using the epoxy monomer is appropriately selected depending on the intended connection temperature, connection time, storage stability and the like. 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 high reactivity, and from the viewpoint of storage stability, the epoxy resin after storage in a thermostat at 40° C. for 10 days. A sulfonium salt that does not change the gel time with the resin composition is preferable.

When an acrylic monomer is used, the curing agent is appropriately selected depending on the desired connection temperature, connection time, storage stability and the like. From the viewpoints of high reactivity and storage stability, organic peroxides or azo compounds having a half-life of 10 hours at a temperature of 40°C or higher and a half-life of 1 minute at a temperature of 180°C or lower are preferable, and a half-life of 10 hours. Is more preferably 60° C. or higher and the half-life of 1 minute is 170° C. or lower, and an organic peroxide or azo compound is more preferable. These curing agents can be used alone or in a mixture, and may be used in a mixture with a decomposition accelerator, a suppressor and the like.

In both cases of using an epoxy monomer and an acrylic monomer, when the connection time is 10 seconds or less, the curing agent is blended in an amount of the monomer described below and the film forming material described below in order to obtain a sufficient reaction rate. The total amount of 100 parts by mass is preferably 0.1 parts by mass to 40 parts by mass, and more preferably 1 part by mass to 35 parts by mass. By setting the amount of the curing agent to be 0.1 part by mass or more, a sufficient reaction rate can be obtained, and good adhesive strength and low connection resistance can be easily realized. On the other hand, by setting the compounding amount of the curing agent to 40 parts by mass or less, it becomes easy to realize good fluidity of the adhesive, storage stability of the adhesive, and good connection resistance.

When an epoxy resin monomer is used as the monomer, a bisphenol type epoxy resin derived from epichlorohydrin and bisphenol A, bisphenol F, bisphenol AD, etc., an epoxy novolak resin derived from epichlorohydrin and phenol novolac or cresol novolac, and glycidyl are used. 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 alone or in combination of two or more.

When an acrylic monomer is used, the radically 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, and styrene derivatives. These may be used alone or in combination of two or more. 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-mentioned curing agent and monomer. A thermoplastic resin is preferably used as the film forming material, and examples thereof include a phenoxy resin, a polyvinyl formal resin, a polystyrene resin, a polyvinyl butyral resin, a polyester resin, a polyacrylic resin, and a polyester urethane resin. Further, these polymers may contain a siloxane bond or a fluorine substituent. These resins may be used alone or in combination of two or more. Among the above resins, it is preferable to use a phenoxy resin from the viewpoint of adhesive strength, compatibility, heat resistance, and mechanical strength.

The larger the molecular weight of the thermoplastic resin, the easier it is to obtain a film-forming property, and the melt viscosity that affects the fluidity of the anisotropic conductive film can be set in a wide range. The weight average molecular weight of the thermoplastic resin is preferably 5,000 to 150,000, and particularly preferably 10,000 to 80,000. When the weight average molecular weight is 5000 or more, good film-forming property is easily obtained, and when it is 150,000 or less, good compatibility with other components is easily obtained.

In the present invention, the weight average molecular weight means a value measured by a gel permeation chromatograph (GPC) using a calibration curve based on standard polystyrene according to the following conditions.
(Measurement condition)

Apparatus: Tosoh Corporation GPC-8020 Detector: Tosoh Corporation RI-8020 Column: Hitachi Chemical Co., Ltd. Gelpack GLA160S+GLA150S Sample concentration: 120 mg/3 mL Solvent: Tetrahydrofuran injection amount: 60 μL Pressure: 2.94×10 6 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 the amount is 5% by weight or more, good film-forming property is easily obtained, and when the amount is 80% by weight or less, the curable composition tends to show good fluidity.

The adhesive layers forming the conductive adhesive layer 13 and the insulating adhesive layer 14 include fillers, softeners, accelerators, antioxidants, colorants, flame retardants, thixotropic agents, couplings. It may further contain agents, phenol resins, melamine resins, isocyanates and the like. 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 platinum group precious metal such as gold or silver. Among these, gold is more preferable. preferable. Further, the surface of nickel 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, and in this case also, a nickel layer may be provided to form a multilayer structure.

In addition, when non-conductive plastic or the like coated with a conductive material or hot-melted metal particles are used as the conductive particles P, the conductive particles P are easily deformed by heating and pressurization, so that the conductive particles P are not The contact area is increased, the thickness variation on the circuit member side is absorbed, and the connection reliability can be improved. Further, the connection resistance can be reduced by providing a protrusion on the surface of the conductive particle P.

The average particle diameter 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 in the conductive adhesive layer 13 easily. By setting the average particle diameter of the conductive particles P to 6.0 μm or less, it becomes easy to maintain the insulating property between the adjacent circuit electrodes 8 of the connection structure 1. In order to obtain good dispersibility of the conductive particles P, the average particle diameter of the conductive particles P is more preferably 2.7 μm or more, further preferably 3 μm or more. On the other hand, from the viewpoint of ensuring insulation between the adjacent circuit electrodes 8 of the connection structure 1, the average particle diameter of the conductive particles P is more preferably 5.5 μm or less, and 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 300 arbitrary conductive particles by observation with 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 the circle circumscribing the conductive particles in the SEM image.

The content of the conductive particles P is preferably 1 part by volume to 100 parts by volume with respect to 100 parts by volume of the components other than the conductive particles P. From the viewpoint of suitably achieving both the dispersibility of the conductive particles P and the insulating property between adjacent circuits at the time of mounting, the compounding amount of the conductive particles P is more preferably 10 parts by volume to 50 parts by volume. Further, 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 particles/mm 2 or more and 50000 particles/mm 2 or less.

The thickness of the conductive adhesive layer 13 and the insulating adhesive layer 14 can be set appropriately. The total thickness of the conductive adhesive layer 13 and the insulating adhesive layer 14 is, for example, 5 μm to 30 μm, but it is desirable to appropriately adjust the thickness 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. When the ratio is 1.0 times or less, the connection structure may not be filled with the anisotropic conductive film, and the adhesiveness and the insulating property deteriorate. 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 from the connection structure in a large amount, and the tact of mounting deteriorates. There arises a problem such as a large deviation from the desired mounting position.

Regarding the thicknesses of the insulating adhesive layer 14 and the conductive adhesive layer 13 constituting the anisotropic conductive film 11, and the positions of the conductive particles P in the anisotropic conductive film 11, for example, a focused ion beam ( It is possible to cut the cross section of the anisotropic conductive film 11 using FIB) and then observe and measure 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. Then, 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 conductive adhesive layer 13 side 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 for producing anisotropic conductive film]

The anisotropic conductive film 11 is manufactured as follows. The long release film 12 is conveyed between the upstream guide roll 51 and the downstream guide roll 52 in a substantially vertical direction from below to above.

A coating roll 53 that applies a resin solution that is a material for forming the conductive adhesive layer 13 is disposed on the conveyance path of the release film 12, and the resin solution in which the conductive particles P are dispersed by the coating roll 53 is disposed. Is applied on 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.

Although the viscosity of the resin solution can be changed depending on the application and the coating method, it is usually preferably 1 mPa·s to 10000 mPa·s. From the viewpoint of suppressing the separation of the compound in the resin solution and improving the compatibility, it is more preferably 10 mPa·s to 1000 mPa·s. Further, in view of the characteristics of the coating method, in order to improve the appearance of the anisotropic conductive film 11, it is preferably 20 mPa·s to 300 mPa·s. When it exceeds 10000 mPa·s, not only it becomes difficult to supply the resin solution to the coating roll 53, but also it becomes difficult to scrape off the supplied resin solution with the doctor blade 58. If it is less than 1 mPa·s, the compound of the adhesive paste W may be separated.

The drying temperature of the resin solution is preferably, for example, 20°C to 80°C. Further, the transport speed of the release film 12 is preferably, for example, 30 mm/s to 160 mm/s. The thickness of the adhesive paste W is preferably 5 μm to 10 μm, for example, when the conductive particles P having an average particle diameter of 3 μm are used.

After the conductive adhesive layer 13 is formed, the separately prepared insulating adhesive layer 14 may be laminated on the conductive adhesive layer 13. As a result, the anisotropic conductive film 11 shown in FIG. 5 is obtained. For laminating the insulating adhesive layer 14, for example, a hot roll laminator can be used. Moreover, the adhesive paste, which is a material of the insulating adhesive layer 14, is not limited to the laminate, and may be applied and dried on the conductive adhesive layer 13.
[Method for manufacturing connection structure]

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

As a result, the adhesive component of the anisotropic conductive film 11 flows, the distance between the bump electrode 6 and the circuit electrode 8 is reduced, and the conductive particles P are meshed with each other, and the conductive adhesive layer and the insulating adhesive layer are formed. 14 hardens. By curing the conductive adhesive layer and the insulating adhesive layer 14, the bump electrodes 6 and the circuit electrodes 8 are electrically connected, and the adjacent bump electrodes 6 and 6 and the adjacent circuit electrodes 8 and 8 are adjacent to each other. The 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 with time, and the long-term reliability of the electrical characteristics. Can be secured.

The heating temperature of the anisotropic conductive film 11 is preferably equal to or higher than the temperature at which polymerization active species are generated in the curing agent and the polymerization of the polymerization monomer is started. The 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. If the heating temperature is less than 80°C, the curing rate will be slow, and if it exceeds 200°C, unwanted side reactions will easily proceed. If the heating time is less than 0.1 seconds, the curing reaction will not proceed sufficiently, and if it exceeds 30 seconds, the productivity of the cured product will be reduced, and undesired side reactions will easily proceed.

As described above, in the method for manufacturing the anisotropic conductive film 11 according to the present invention, it is possible to disperse and arrange the conductive particles P in the anisotropic conductive film 11 in the cell pattern of the coating roll. Further, the connection structure using the anisotropic conductive film 11 according to the present invention can achieve both connection reliability and insulation.

Hereinafter, examples and comparative examples of the present invention will be described.
(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-neck flask equipped with a Dimroth condenser, a calcium chloride tube, and a Teflon stir bar (Teflon is a registered trademark) connected to a stir motor to prepare a reaction solution. And 21 g of potassium carbonate was added thereto, and the mixture was stirred while being heated to 110° C. with a mantle heater. After stirring for 3 hours, the reaction solution was added dropwise to a beaker containing 1000 mL of methanol, and the formed precipitate was collected by suction filtration. The precipitate collected by filtration was further washed with 300 mL of methanol three times to obtain 75 g of phenoxy resin a.

Then, 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 was 15769, Mw was 38045, and Mw/Mn was 2.413 in terms of polystyrene.

Next, when forming the resin solution for the conductive adhesive layer, bisphenol A type epoxy resin (manufactured by Mitsubishi Chemical Corporation: jER828) is used as an epoxy compound in a solid content of 50 parts by mass, and 4-hydroxyphenylmethylbenzyl as a curing agent. 5 parts by mass of sulfonium hexafluoroantimonate as a solid content and 50 parts by mass of phenoxy resin a as a film forming material as a solid content were compounded. Further, regarding the conductive particles, a nickel layer having a thickness of 0.2 μm is provided on the surface of the particles having polystyrene as a nucleus, and conductive particles having an average particle diameter of 3 μm and a specific gravity of 2.5 are prepared. It was added to the resin composition. Then, a PET resin film having a thickness of 50 μm was applied using a coating roll having a regular hexagonal engraving 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 the adhesive paste for the insulating adhesive layer, bisphenol F type epoxy resin (manufactured by Mitsubishi Chemical Corporation: jER807) is used as an epoxy compound in a solid content of 45 parts by mass, and 4-hydroxyphenylmethyl is used as a curing agent. 5 parts by mass of benzylsulfonium hexafluoroantimonate as a solid content, and 55 parts by mass of a phenoxy resin b having a Mw of 50000.Tg of 70° C. as a film forming material as a solid content. Then, it was applied to a PET resin film having a thickness of 50 μm using a coater and dried with hot air at 70° C. for 5 minutes to obtain an insulating adhesive layer having a thickness of 16 μm. After that, 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 engraving with 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 a regular triangle engraving with 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 a gap of 5 μm and a depth of 3 μm was used.
(Calculation of density of conductive particles in anisotropic conductive film)

Regarding 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 metallurgical microscope at 20 places, and the average value was converted to 1 mm 2.
(Evaluation of monodispersion rate of conductive particles)

For the anisotropic conductive films of Examples 1 to 3 and Comparative Example 1, the monodispersity of the conductive particles (the ratio of the conductive particles existing in a state of being separated from other adjacent conductive particles (monodispersed state)) was determined. evaluated. The monodispersity ratio is obtained by using the monodispersion ratio (%)=(the number of conductive particles in a monodispersed state in 2500 μm 2 /the number of conductive particles in 2500 μm 2 )×100. The conductive particles were actually measured using a metallurgical microscope at a magnification of 200 times.

FIG. 10 is a diagram showing the evaluation experiment results. As shown in the figure, in each of the anisotropic conductive films according to Examples 1 to 3 and Comparative Example 1, the conductive particle density was 30,000±2000 particles/mm 2. However, the monodispersity ratio of Comparative Example 1 is 40%, whereas the monodispersion ratio of Examples 1 to 3 exceeds 70%, and good monodispersity is obtained.
(Preparation of connection structure)

As the first circuit member, an IC chip having a straight arrangement structure in which bump electrodes are arranged in a line (outer shape 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. Further, as the second circuit member, a glass substrate (#1737, manufactured by Corning: #1737, 38 mm×28 mm, thickness 0.3 mm) on which an ITO wiring pattern (pattern width 21 μm, inter-electrode space 17 μm) was formed Got ready.

A thermocompression bonding device including a stage (150 mm×150 mm) made of a ceramic heater and a tool (3 mm×20 mm) was used for connecting the IC chip and the glass substrate. First, the release film on the conductive adhesive layer of the anisotropic conductive films (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. Then, it was heated and pressed for 2 seconds under the conditions of 80° C. and 0.98 MPa (10 kgf/cm 2) to be stuck.

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 measured maximum of the anisotropic conductive film was measured. The insulating adhesive layer was attached to the IC chip by heating and pressurizing for 5 seconds under the conditions of the ultimate temperature of 170° C. and the area conversion pressure of the bump electrode of 70 MPa.
(Evaluation of capture rate of conductive particles and resistance characteristics)

In the connection structures obtained by using the anisotropic conductive films of Examples 1 to 3 and Comparative Example 1, the trapping rate of conductive particles between the bump electrode and the circuit electrode, the contact ratio between the bump electrode and the circuit electrode And the insulation resistance between adjacent circuit electrodes were evaluated. The capture rate is the 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 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.

The resistance value was evaluated by the four-terminal measuring method, and the average value of the measurements at 14 points was used. In the evaluation of the insulation resistance, a voltage of 50 V was applied to the connection structures obtained by using the anisotropic conductive films of Examples 1 to 3 and Comparative Example 1, and the insulation resistance between the circuit electrodes at 1440 places in total. Was measured collectively. Regarding the insulation resistance, the case where it is larger than 108Ω was judged as A, and the case where it was 108Ω or less was judged as B.

FIG. 11 is a diagram showing the evaluation experiment results. As shown in the figure, in all of the connection structures according to Examples 1 to 3 and Comparative Example 1, the capture rate of conductive particles was around 50%, and the resistance value was good. On the other hand, the insulation test evaluation of the connection structures according to Examples 1 to 3 is A, but the insulation test evaluation of the connection structures according to Comparative Example 1 is B, which is lower than those 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 an anisotropic conductive film, 5... Main part of 1st circuit member, 6... Bump electrode, 7 ... Main part of second circuit member, 8... Circuit electrode, 11... Anisotropically conductive film, 12... Release film, 13... Conductive adhesive layer, 14... Insulating adhesive layer, 53... Coating roll, P... Conductive particles.

Claims (7)

A method for producing an anisotropic conductive film having an adhesive layer containing conductive particles and an adhesive component,
Anisotropic conductive film resin solution obtained by dissolving conductive particles and adhesive components in an organic solvent is supplied as a material for forming the adhesive layer on the surface of the coating roll of the coating device, and an extra anisotropic conductive film resin solution is supplied. After scraping, there is a step of applying an anisotropic conductive film resin solution on the surface of the coating roll onto the release film,
In the coating device, the release film is conveyed in the vertical direction by the upstream guide roll and the downstream guide roll, and the coating unit that coats the anisotropic conductive film resin solution on the coating roll is the coating unit. It is lined up horizontally with the roll,
The peripheral surface of the coating roll has an irregularly-shaped polygonal pattern that is regularly arranged,
The coating roll is pressed against the release film at a contact angle of 0° to 10° (excluding 0°) by the upstream guide roll and the downstream guide roll,
By the coating roll, while applying the anisotropic conductive film resin solution on the release film, the conductive particles are arranged on the release film from the groove of the processing, anisotropic conductive film characterized by Manufacturing method. The method for producing an anisotropic conductive film according to claim 1, wherein the polygonal concave-convex processing is a regular triangle, a square, a regular pentagon, or a regular hexagon. 3. The anisotropic conductive material according to claim 1, wherein the depth of the groove of the polygonal uneven processing is 0.5 times or more and 1.1 times or less the diameter of the conductive particles. Of producing a flexible film. The anisotropic conductive film, a conductive adhesive layer consisting of an adhesive layer in which the conductive particles are dispersed, is laminated on the conductive adhesive layer, from the adhesive layer in which the conductive particles are not dispersed The insulating adhesive layer which consists of this, The manufacturing method of the anisotropic conductive film as described in any one of Claims 1-3. The method for producing an anisotropically conductive film according to any one of claims 1 to 4, wherein the coating roll rotates in a direction opposite to a transport direction of the release film. The conductive particles, method of manufacturing the anisotropic conductive film of any one of claims 1-5, characterized in that the coated plastic or thermal melting metal particles with a conductive material. The conductive particles, method of manufacturing the anisotropic conductive film according to claim 1-6 any one characterized by having a projection on the surface.

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