JP3582654B2 - Connection member - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a connection member used for bonding and fixing an electronic component and a circuit board, and bonding and fixing the circuit boards to each other and electrically connecting both electrodes.
[0002]
[Prior art]
In recent years, as electronic components have become smaller and thinner, circuits used for them have become higher density and higher definition, and it is difficult to connect such electronic components and fine electrodes with conventional solders or rubber connectors. For this reason, recently, anisotropic conductive adhesives and film-like materials (hereinafter, referred to as connection members) having excellent resolution are frequently used. The connection member is made of an adhesive containing a predetermined amount of conductive particles. The connection member is provided between the connection electrode of the electronic component and the circuit electrode of the circuit board, and includes a pressurizing or heating pressurizing unit. As a result, the 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 connection member is to make the particle size of the conductive particles smaller than the insulating portion between the adjacent electrodes, thereby ensuring insulation between the adjacent electrodes, and at the same time, By setting the content of the particles in a range in which the particles do not come into contact with each other, conductivity at the connection portion can be reliably obtained.
[0003]
However, if the particle size of the conductive particles is reduced, the particles will undergo secondary aggregation due to a remarkable increase in the particle surface area, making it impossible to maintain insulation between adjacent electrodes. Since the number of conductive particles on the circuit also decreases, the number of contact points with the electrodes becomes insufficient, and conduction between the connection electrodes cannot be obtained, so it is not possible to improve the resolution of the connection member while maintaining long-term connection reliability It was extremely difficult.
[0004]
[Problems to be solved by the invention]
As a connection member which enables connection of such fine electrodes and circuits and has excellent connection reliability, we have previously proposed a connection member having a dense area of conductive particles in a necessary part. According to this, it is 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 at a necessary portion is brought into planar contact with a sticky adhesive, and conductive particles are sprinkled from the top of the metal mask to remove excess conductive particles. Is removed to produce a connection member. As another means, it is possible to spray conductive particles from above the metal mask by using a liquid crystal spacer spraying device, or to fabricate the device by a silk screen printing method. These methods are excellent as a method for easily obtaining a small-area, high-precision connection member, but for example, a long product such as a continuous tape-shaped wound body cannot be obtained, and it is difficult to perform industrial mass production. There were drawbacks. When the connection member is a long product, continuous connection work becomes possible. The present invention has been made in view of the above drawbacks, and has as its object to provide a long connecting member having a dense array of conductive particles in a predetermined arrangement.
[0005]
[Means for Solving the Problems]
The present invention, conductive particles child becomes covered fixed by the adhesive layer, conductive particles children form a dense region, the number of conductive particles in the dense zone three or more, dense area of the conductive particles Is a connection member formed at the top of an equilateral triangle arranged without gaps and having a distance d between perpendiculars from ends of adjacent dense areas smaller than the distance between electrodes to be connected . Et al of the present invention, the conductive particles are preferably connected member If it is insulating coating particles.
[0006]
Hereinafter, the present invention will be described with reference to the drawings. FIG. 1 is a schematic cross-sectional view illustrating one embodiment of a method for manufacturing a connection member according to the present invention. A typical example of the cylindrical rotating body 1 is a roll shape. The material is preferably a rigid metal from the viewpoint of improving the accuracy of forming a dense area. As a method of forming the dense area 3 of the conductive particles on the surface 2 in a predetermined arrangement, for example, the surface 2 of the roll is formed in an intaglio or in a relief form (not shown), and the dense area of the conductive particles is formed in that portion. There is a method of gravure printing in which a fixed amount is formed with a doctor knife 4 or the like. In this case, when the conductive particles are a liquid material composed of a polymer binder and a solvent, the forming operation is easy.
[0007]
Further, as means suitable for carrying out the method for manufacturing a connection member of the present invention, a cylindrical rotating body having a through hole on a surface described later, and a supply amount control device for conductive particles provided inside the cylindrical rotating body, which will be described later, are provided. It can also be formed by a device comprising pressure means. The contact Chakufu Irumu 5 facing traveling material showing curability by thermoplastic material and heat or light can be widely applied. It is preferable to use a curable material because of its excellent heat resistance and moisture resistance after connection. Among them, the epoxy adhesive can be preferably applied because it can be cured in a short time, has good connection workability, and has excellent adhesiveness due to its molecular structure.
[0008]
Epoxy adhesives are, for example, high-molecular-weight epoxies, solid epoxies, liquid epoxies, and epoxies modified with urethane, polyester, NBR, etc. as the main components, and added with curing agents, catalysts, coupling agents, fillers, etc. Is common. The thickness of the contact Chakufu Irumu 5, thinner is preferably in a range capable of obtaining adhesion in terms of accuracy dense region formed of conductive particles, 50 [mu] m or less, more preferably 35μm or less. The adhesive film 5 may be reinforced with a flexible base material 6 such as a plastic film as needed.
[0009]
Transfer means for contacting Chakufu Irumu 5, a dense zone of the conductive particles may be pressure transfer, the contact Chakufu Irumu 5 exhibits tack at around room temperature, arranged and fixed in the conductive particles can easily Is preferred. The adhesive film on which the conductive particles are arranged and fixed is the connecting member according to the present invention, and can be wound as a continuous long product. At this time, to hold the dense region of the conductive particles, it is also possible to embed different contact Chakufu Irumu 5 further optionally or as sandwiched by lamination by hot roll in contact Chakufu Irumu 5. Further, for the purpose of improving the adhesive properties, a liquid material (adhesive, adhesion promoter, cross-linking agent, etc.) can be formed thin.
[0010]
The dense region 3 of the conductive particles 7 is described with reference to FIG. As shown in FIG. 2, the dense area 3 of the conductive particles 7 maintains insulation without conducting the adjacent parallel electrodes, and at least a part of the dense area is always sandwiched between all the connected parallel electrodes. To place. In FIG. 2 , d is the closest distance between the dense areas in the X-axis direction. The direction intersecting the line-shaped fine electrode having many parallel electrodes at the time of connection is defined as the X-axis, and the direction parallel thereto is defined as the Y-axis.
[0011]
The number of dense zone 3 in the conductive particles 7, may if one is to the principle as illustrated in part in FIG. 2, and 3 or more. More preferably, it is preferable that the number be five or more because connection reliability is improved. The conductive particles 7 may be buried in the surface of the adhesive film 5 or in an adhesive as shown in FIG. Examples of the conductive particles 7 include metal particles such as Au, Ag, Ni, Cu, W, Sb, Sn, and solder, and carbon, and polymer core materials such as non-conductive glass, ceramics, and plastic. Alternatively, the conductive layer described above may be formed by coating or the like. Further conductive particles such as described above formed by coating with an insulating layer insulating coating particles children can also be applied.
[0012]
A conductive layer formed on a hot-melt metal such as solder or a polymer nucleus material such as plastic has deformability due to heating and pressing or pressurizing, and the contact area with the circuit increases during lamination and reliability is improved. It is preferable because it improves. In particular, when a polymer is used as a core, a softened state can be widely controlled by a connection temperature since a melting point is not exhibited unlike solder, and a connection member which can easily cope with variations in electrode thickness and flatness is preferable, which is preferable. In the case of hard metal particles such as Ni and W, for example, conductive particles penetrate electrodes and wiring patterns, so that a low connection resistance can be obtained even when an oxide film or a contaminant layer is present. It is effective for controlling expansion and contraction, and reliability is improved.
[0013]
The production apparatus suitable for the practice of the connecting member of the present invention will be described with reference to FIG. The cylindrical rotator 1 having a through hole 8 on its surface is, for example, a metal mask having 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 according to the number and the number of layers of the conductive particles 7, and includes, for example, a doctor knife and a roll that can control a gap with the cylindrical rotary member 1. Pressurizing means 10 is for transferring placing conductive particles 7 into contact Chakufu Irumu 5 can be exemplified by roll or the like that rotates in accordance with the cylindrical rotating body 1. In this case, if the pressing means 10 has a protruding portion that coincides with the through hole 8, the pressure transfer is more advantageous. Conductive particles 7 discharged from the through hole by pressing means 10, against Chakufu Irumu 5 is adhered can be a continuous example the rolled 12 as long article by the traveling means 11. In the case of FIG. 3 , it is preferable to reduce the thickness of the cylindrical rotating body so as to approach the particle diameter of the conductive particles 7 because the precision of fine arrangement of the dense area is improved. Since this method can be performed in a dry system 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.
[0014]
The connecting member of the present invention forms a dense area of the conductive particles on the main surface of the cylindrical rotating body, is brought into contact with the facing adhesive film, and transfers the dense area of the conductive particles to the adhesive film. According to the manufacturing method and the manufacturing apparatus suitable for the manufacturing method, a long product such as a continuous tape-shaped wound body can be easily obtained. That is, since the formation of the dense area of the conductive particles is transferred to the adhesive film running as an endless cylindrical shape, and the conductive particle dense area can be sequentially formed and supplied to the cylindrical rotating body, the industrial production of high-precision long connection members is possible. Mass production becomes easy.
[0015]
【Example】
Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited thereto.
[0016]
Example 1
An array of equilateral triangles as shown in FIG. 2, without gaps arranged that stainless metal mask (thickness 10 [mu] m having a circular through-hole, such as centered at each vertex, pore diameter 30 [mu] m, pitch 80 [mu] m, d = 10 [mu] m ) Was formed into a cylindrical shape having a diameter of 100 mm, and a rotating shaft was formed at the center of the side surface and a supply port for conductive particles was formed above the rotating shaft. The cylindrical surface has been subjected to a Teflon (trademark) -based release treatment to avoid unnecessary contact with the adhesive film. Further, a doctor knife and a pressure roll having a diameter of 10 mm are provided inside the cylindrical shape according to the arrangement shown in FIG. As the conductive particles, plated plastic spheres having a particle diameter of 5 μm and having a Ni / Au composite conductive layer on the surface of a core material made of cross-linked polystyrene were used. The conductive particles are supplied from the supply port and pass through a doctor knife controlled to eliminate the gap with the cylinder, and the conductive particles are bonded to the adhesive film by the weight of the rotating rubber roll which is a pressing means formed at the lower part of the supply port. And transfer it to The contact Chakufu Irumu, on a substrate made of a separator treated release agent the polyester film, using an adhesive having a room temperature tacky thickness 20μm consisting mainly of high molecular weight epoxy, 1 m / min speed The sheet was allowed to run, and was brought into contact with a cylindrical surface whose peripheral speed was synchronized to transfer the image. Thereafter, the separator was bonded by a roll laminator. Therefore, the conductive particles were precisely arranged in a form buried in the adhesive film. Thus, a continuous tape-shaped wound body could be manufactured.
[0017]
Example 2
Same as Example 1, except that instead of a metal mask having through holes, a gravure roll in which a dense area is concavely formed in the same arrangement was used, and the conductive particles were dispersed in a 5% methanol solution of soluble nylon to form a liquid material. . The conductive particles were 20% by volume of nylon. Since the adhesive film was insoluble in methanol, it could be transferred and arranged, and was blow-dried at 50 ° C. before winding to remove methanol. In addition, since the surface of the conductive particles was an insulating coated particle obtained by coating the surface with a nylon insulating layer having a melting point of 130 ° C., it was easy to arrange and form a dense area. According to the present example, it was possible to produce a continuous tape-shaped wound body even by the gravure roll method.
[0018]
【The invention's effect】
As described above, the connection member of the present invention enables industrial mass production of high-precision long connection members, improves connection reliability, and ensures that dense areas of conductive particles are arranged without gaps. When formed at the top of the triangle, the alignment of the connection between the electronic component and the fine electrode becomes unnecessary, and if the conductive particles are insulating coating particles, the dense area can be easily formed and formed, and the insulating property between adjacent electrodes can be improved. And connection reliability is improved.
[Brief description of the drawings]
FIG. 1 is a sectional view showing one embodiment of a method for manufacturing a connection member of the present invention.
FIG. 2 is a schematic plan view showing a dense arrangement of conductive particles of a connection member of the present invention.
FIG. 3 is a schematic sectional view showing a manufacturing apparatus suitable for implementing the connecting member of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Cylindrical rotating body 2 Main surface part 3 Dense area 4 Doctor knife 5 Adhesive film 6 Base material 7 Conductive particles 8 Through hole 9 Supply control device 10 Pressurizing means 11 Running means 12 Winding body

Claims (2)

The conductive particles child becomes covered fixed by the adhesive layer, conductive particles child forms a dense area, the number of conductive particles in the dense zone three or more, dense area of the conductive particles, without a gap A connection member formed at the top of the arranged equilateral triangles and having a distance d between perpendiculars from ends of adjacent dense areas smaller than a distance between electrodes to be connected. The connecting member according to claim 1, wherein the conductive particles are insulating coating particles.

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