JP3994335B2 - Manufacturing method of connecting member - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electronic component and a circuit board, and a method for manufacturing a long connection member used for bonding and fixing circuit boards together and electrically connecting both electrodes.
[0002]
[Prior art]
In recent years, with the miniaturization and thinning of electronic components, the circuits used for these have become high density and high definition, and it is difficult to connect such electronic components and fine electrodes with conventional solder or rubber connectors. For this reason, recently, anisotropic conductive adhesives and film-like materials (hereinafter referred to as connection members) having excellent resolution have been frequently used. This connection member is made of an adhesive containing a predetermined amount of conductive particles. This connection member is provided between the connection electrode of the electronic component and the circuit electrode of the circuit board, and constitutes a pressurizing or heating and pressing means. The two electrodes are electrically connected to each other, and the electrodes formed adjacent to the electrodes are provided with insulating properties so that the electronic component and the circuit are bonded and fixed. . The basic idea for increasing the resolution of the connecting member is to ensure the insulation between adjacent electrodes by making the particle size of the conductive particles smaller than the insulating portion between the adjacent electrodes. By setting the content of the particles within a range in which the particles do not contact each other, conductivity at the connection portion can be obtained with certainty.
[0003]
However, if the particle size of the conductive particles is reduced, the particles cause secondary agglomeration due to a significant increase in the particle surface area, so that insulation between adjacent electrodes cannot be maintained. Since the number of conductive particles on the circuit also decreases, the number of contact points with respect to the electrodes is insufficient, and continuity between the connection electrodes cannot be obtained. Therefore, it is possible to increase the resolution of the connection member while maintaining long-term connection reliability. It was extremely difficult.
[0004]
[Patent Document 1]
Japanese Patent Laid-Open No. 03-008213 [Patent Document 2]
Japanese Patent Laid-Open No. 64-054608 [Patent Document 3]
Japanese Patent Laid-Open No. 01-258943
[Problems to be solved by the invention]
As a connection member capable of connecting such fine electrodes and circuits and having excellent connection reliability, we previously proposed a connection member having a dense region of conductive particles in a necessary portion. According to this, it becomes possible to connect a dot-shaped electrode such as a semiconductor chip having a pitch of 200 μm or less, or a line-shaped fine electrode having a large number of insulated parallel electrodes such as TAB and FPC. In any of the above methods, a metal mask having a through-hole in a necessary part is brought into contact with a sticky adhesive in a plane, and the conductive particles are sprinkled on the metal mask to remove excess conductive particles. The connection member is produced by removing the. Further, as another means, it is possible to produce conductive particles by spraying conductive particles from a metal mask with a liquid crystal spacer spraying device or by silk screen printing. These methods are excellent as a method for easily obtaining a high-precision connecting member having a small area, but long products such as a continuous tape-shaped wound body cannot be obtained, and it is difficult to perform industrial mass production. There were drawbacks. If the connecting member is a long product, continuous connection work is possible. The present invention has been made in view of the above-described drawbacks, and an object thereof is to provide a long connection member having a dense area of conductive particles in a predetermined arrangement.
[0006]
[Means for Solving the Problems]
The present invention includes a step of forming a dense area of conductive particles on a main surface of a cylindrical rotating body by a metal mask or gravure printing, and conductive particles on the surface of a curable adhesive film that runs facing the cylindrical rotating body. The process of placing three or more dense areas by pressure transfer and arranging the conductive particles is fixed to the adhesive film by laminating another adhesive film or embedding in the adhesive film with a hot roll. A step, a step of making the connecting member that has undergone the above-mentioned means into a long wound body, and a method of producing a long connecting member formed by covering and fixing conductive particles formed with an adhesive layer. Moreover, this invention is a manufacturing method of a preferable elongate connection member in which electroconductive particle is insulation coating particle.
[0007]
The present invention will be described below with reference to the drawings. FIG. 1 is a schematic cross-sectional view for explaining one embodiment of a method for producing a connecting member of the present invention. As the cylindrical rotating body 1, for example, a roll shape is representative. The material is preferably a rigid metal from the viewpoint of improving the accuracy of forming dense areas. As a method of forming the conductive particle dense area 3 on the surface 2 in a predetermined arrangement, for example, the surface 2 of the roll is formed in an intaglio or a letterpress shape (not shown), and the conductive particle dense area is formed in that portion. There is a gravure printing technique in which a fixed amount is formed with a doctor knife 4 or the like. In this case, if the conductive particles are a liquid consisting of a polymer binder and a solvent, the forming operation is easy.
[0008]
Further, as means suitable for carrying out the manufacturing method of the connection member of the present invention, a cylindrical rotating body having a through-hole on the surface, which will be described later, a supply amount control device for conductive particles provided inside the cylindrical rotating body, and an addition It can also be formed by a device comprising a pressure means. As the adhesive film 5 that runs face to face, a thermoplastic material or a material that exhibits curability by heat or light can be widely applied. Application of a curable material is preferred because of excellent heat resistance and moisture resistance after connection. Among these, epoxy adhesives can be preferably applied from the viewpoints that they can be cured in a short time, have good connection workability, and have excellent adhesion due to their molecular structure.
[0009]
Epoxy adhesives are mainly composed of high molecular weight epoxy, solid epoxy and liquid epoxy, urethane, polyester, epoxy modified with NBR, etc., and added with curing agents, catalysts, coupling agents, fillers, etc. Is common. The thickness of the adhesive film 5 is preferably as thin as possible in the range in which adhesiveness can be obtained from the viewpoint of improving the accuracy of formation of dense areas of conductive particles, and is preferably 50 μm or less, more preferably 35 μm or less. The adhesive film 5 may be reinforced with a flexible substrate 6 such as a plastic film as necessary.
[0010]
The transfer means to the adhesive film 5 only needs to pressure-transfer the dense area of the conductive particles. If the adhesive film 5 exhibits tackiness near room temperature, it is preferable because the conductive particles can be placed and fixed easily. . The adhesive film on which conductive particles are arranged and fixed is a connecting member in the present invention, and can be wound as a continuous long product. At this time, in order to maintain a dense region of conductive particles, another adhesive film 5 ′ may be laminated to form a sandwich as necessary, or may be embedded in the adhesive film 5 by a hot roll. Further, for the purpose of improving adhesive properties, a liquid material (adhesive, adhesion promoter, cross-linking agent, etc.) can be formed thinly.
[0011]
The dense region 3 of the conductive particles 7 will be described with reference to FIGS. 2 and 3. The dense areas 3 of the conductive particles 7 are arranged so that the dense areas always exist in accordance with the dots arranged like a semiconductor chip as shown in FIG. 2, or are adjacent as shown in FIG. The parallel electrodes are arranged so as to maintain insulation without conducting the electrodes, and at least a part of the dense area is always sandwiched between all the parallel electrodes to be connected. In FIG. 3, d is the closest distance between the dense areas in the X-axis direction, and the direction intersecting the line-shaped fine electrode having a large number of parallel electrodes at the time of connection is the X-axis, and the parallel direction is the Y-axis.
[0012]
The number of the conductive particles 7 in the dense region 3 is preferably 3 or more, more preferably 5 or more , as exemplified in a part of FIGS. 2 and 3, since the connection reliability is improved. The conductive particles 7 may be embedded in an adhesive as shown in FIG. 1 on the surface of the adhesive film 5. Examples of the conductive particles 7 include metal particles such as Au, Ag, Ni, Cu, W, Sb, Sn, and solder, carbon, and the like, and polymer core materials such as non-conductive glass, ceramics, and plastics. In addition, the conductive layer described above may be formed by coating or the like. Furthermore, insulating coating particles obtained by coating the above-described conductive particles with an insulating layer, or a combination of conductive particles and insulating particles can be applied.
[0013]
Heat-melting metal such as solder or polymer core material such as plastic formed with a conductive layer is deformable by heat or pressure, increasing the contact area with the circuit during lamination and increasing reliability. Since it improves, it is preferable. In particular, when a polymer is used as a nucleus, it does not show a melting point like solder, so that the softening state can be widely controlled by the connection temperature, and a connection member that can easily cope with variations in electrode thickness and flatness is obtained. Also, for example, in the case of hard metal particles such as Ni and W, the conductive particles pierce the electrodes and the wiring pattern, so that a low connection resistance can be obtained even in the presence of an oxide film or a contaminated layer, and in addition, by fixing the connection portion It is also effective in controlling expansion and contraction and improves reliability.
[0014]
A manufacturing apparatus suitable for carrying out the method for manufacturing a connection member of the present invention will be described with reference to FIG. The cylindrical rotating body 1 having a through-hole 8 on the surface is, for example, a metal mask formed in a cylindrical shape, and a conductive particle supply control device 9 and a pressurizing means 10 are provided therein. The supply control device 9 controls the amount by the number of conductive particles 7 and the number of layers, and includes, for example, a doctor knife or a roll that can control the gap with the cylindrical rotating body 1. The pressurizing means 10 transfers the conductive particles 7 to the adhesive film 5 and can be exemplified by a roll that rotates in accordance with the cylindrical rotating body 1. In this case, if the pressurizing means 10 has a projecting portion that coincides with the through hole 8, the pressure transfer is further advantageous. The conductive particles 7 discharged from the through-holes by the pressurizing means 10 can be attached to the adhesive film 5 and used as, for example, a wound body 12 as a continuous product by the running means 11. In the case of FIG. 4, it is preferable to reduce the thickness of the cylindrical rotating body to be close to the particle diameter of the conductive particles 7 because the accuracy of fine arrangement in the dense area is improved. Since this method can be performed under a dry method without using a dispersion medium, the concentration of the conductive particles in the main part can be formed densely, and the cleaning operation is easy.
[0015]
In the method for producing a connecting member according to the present invention, a dense region of conductive particles is formed on a main surface of a cylindrical rotating body, and is brought into contact with an adhesive film that travels oppositely, and the dense region of conductive particles is transferred to the adhesive film. With the manufacturing method of the connecting member and the manufacturing apparatus suitable for it, a long product such as a continuous tape-shaped wound body can be easily obtained. In other words, it is possible to transfer the formation of dense areas of conductive particles to an adhesive film that travels as an endless cylindrical shape, and sequentially form and supply the dense areas of conductive particles to a cylindrical rotating body. Mass production becomes easy.
[0016]
【Example】
Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited thereto.
[0017]
Example 1
A stainless steel metal mask having a circular through-hole arranged in a regular triangle arrangement as shown in FIG. 3 and having a center at each apex thereof (thickness 10 μm, hole diameter 30 μm, pitch 80 μm, d = 10 μm) ) In the shape of a cylinder with a diameter of 100 mm, and a rotating shaft at the center of the side surface and a supply port for conductive particles at the top. The cylindrical surface is subjected to a Teflon (trademark) -based release treatment to avoid unnecessary contact with the adhesive film. A cylindrical knife is provided with a doctor knife and a pressure roll having a diameter of 10 mm in accordance with the arrangement shown in FIG. As the conductive particles, plated plastic spheres having a particle diameter of 5 μm having a Ni / Au composite conductive layer on the surface of a core material made of crosslinked polystyrene were used. The conductive particles are supplied from the supply port, passed through a doctor knife controlled so as to eliminate the gap with the cylinder, and the conductive particles are adhered to the adhesive film by the weight of the rotating rubber roll as a pressurizing means formed at the lower part of the supply port. Place the transfer to. As the adhesive film, a sticky adhesive having a thickness of 20 μm, which is mainly composed of a high molecular weight epoxy, is used on a substrate made of a separator obtained by treating a polyester film with a release agent, and travels at a speed of 1 m / min. Then, it was transferred in contact with a cylindrical surface whose peripheral speed was synchronized. Thereafter, the separator was bonded with a roll laminator. Therefore, the conductive particles were arranged with high precision in the form of being buried in the adhesive film (the conductive particle layer was fixed by covering with an adhesive layer). The continuous tape-shaped winding body was able to be manufactured by the above.
[0018]
Example 2
Although it is the same as that of Example 1, the gravure roll which formed the concavity in the same arrangement | positioning concavely was used instead of the metal mask which has a through-hole, and electroconductive particle was disperse | distributed to 5% methanol solution of soluble nylon, and it was set as the liquid substance. . The conductive particles were 20% by volume of nylon. Since the adhesive film was insoluble in methanol, transfer arrangement was possible, and the methanol was removed by blowing at 50 ° C. before winding. Further, since the surface of the conductive particles is an insulating coating particle formed by coating with a nylon insulating layer having a melting point of 130 ° C., it is easy to form and arrange a dense region. According to this example, it was possible to produce a continuous tape-shaped wound body even by the gravure roll method.
[0019]
【The invention's effect】
As described above, the connecting member of the present invention enables industrial mass production of a long and highly accurate connecting member, and when the conductive particle layer is covered and fixed with an adhesive layer, it is easy to form and form a dense area. Thus, the insulation between adjacent electrodes is excellent, and the connection reliability is improved.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an embodiment of a method for producing a connecting member according to the present invention.
FIG. 2 is a schematic plan view showing a dense arrangement of conductive particles of the connection member of the present invention.
FIG. 3 is a schematic plan view showing a dense arrangement of conductive particles of the connection member of the present invention.
FIG. 4 is a schematic cross-sectional view showing a manufacturing apparatus suitable for implementing the connecting member of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Cylindrical rotary body 2 Main part of surface 3 Dense area 4 Doctor knife 5 Adhesive film 6 Base material 7 Conductive particle 8 Through-hole 9 Supply control apparatus 10 Pressurizing means 11 Traveling means 12 Roll body

Claims (2)

A process of forming a dense area of conductive particles on the main surface of the cylindrical rotating body with a metal mask or gravure printing, and there are three or more conductive particles on the surface of the curable adhesive film that faces the cylindrical rotating body. A step of pressure-transferring and arranging the dense area to be formed, a step of fixing the conductive particle placement surface to the adhesive film by laminating another adhesive film or embedding in the adhesive film with a heat roll, the above means a step of the connecting member and the elongate the rolled passed through the manufacturing method of the elongated connecting member formed by coating fixed to become more conductive particles in the adhesive layer.   The method for producing a long connection member according to claim 1, wherein the conductive particles are insulating coating particles.

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