JP4181239B2 - Connecting member - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electronic component and a circuit board, and a connection member that bonds and fixes circuit boards together and electrically connects both electrodes.
[0002]
[Prior art]
In recent years, with the miniaturization and thinning of electronic components, circuits used for these have become denser and higher definition. The connection between the fine electrodes of such electronic components and the substrate is difficult to handle with conventional solder or rubber connectors, and recently, anisotropically conductive adhesives and film-like materials (hereinafter referred to as “high resolution”). (Referred to as a connecting member).
This connecting member is made of an adhesive containing a predetermined amount of a conductive material such as conductive particles. This connecting member is provided between an electronic component and a substrate or between an electrode and a circuit, and a heating or heating / pressing means is provided. The electrodes are electrically connected to each other, and the electrodes formed adjacent to the electrodes are provided with insulation so that the electronic component and the circuit are bonded and fixed.
[0003]
The basic idea for increasing the resolution of the connecting member is to ensure the insulating property of the adjacent electrodes by making the particle size of the conductive particles smaller than the gap between the adjacent electrodes, and also the content of the conductive particles. By ensuring that the particles are not in contact with each other and reliably present on the electrodes, the conductivity at the connecting portion is obtained.
[0004]
[Problems to be solved by the invention]
The conventional technique has a shape in which one or more anisotropically conductive connecting members are formed on a film substrate. In this technique, a connection member is temporarily crimped to one of the two electrode portions to be connected, the electrodes that are facing each other after the film substrate is peeled off, and the heating is applied at a higher temperature than at the time of temporary crimping. Connections have been made under pressure conditions. When the temperature of this temporary press-bonding is increased, the film substrate is easily peeled off from the connection member, but the connection reliability of the connection member during the main press-bonding is lost. In addition, if the electrode to be temporarily bonded is contaminated in the previous step, the connecting member does not peel from the film base material when the film base material is peeled off, causing a problem that the connecting member is peeled off from the electrode.
Further, in recent years, along with the increase in demand for electronic components, tool type and roller type temporary crimping methods that shorten the temporary crimping time are performed by improving the workability of connecting electronic components and circuits, that is, shortening the tact time. It has become like this.
In these methods in which the connection time is shortened, the connecting member does not peel from the film base material when the film base material is peeled off, and there is a tendency that the connection member is peeled off from the electrode together. In particular, the roller-type temporary pressure bonding method is different from the conventional temporary pressure bonding with a heated metal tool, and is heated and pressure-bonded with a metal roller so that the heating time is short. Also in such a method, the connection member which can peel a film base material easily after temporary crimping is required.
However, if it is easy to peel off from the film substrate, there is a risk of peeling from the sheet or roll-shaped roll before heating and pressing.
Moreover, PET, Teflon, etc. are common as a film base material, but it cannot be reused after use, resulting in industrial waste, resulting in a problem in environmental protection.
[0005]
The present invention has been made in view of such a situation, and since a base material is not required by the base function-providing insulating adhesive layer, there is no problem of peeling of the base material at the time of provisional pressure bonding, without industrial waste, and at the time of connection. Since the conductive particles can be kept from flowing out of the electrode with little contact, and the contact between the electrode and the conductive particles is easy to obtain and it is difficult to contain bubbles in the connection part, the long-term connection reliability is excellent, and the conductive particles and the electrode are accurately connected. An object of the present invention is to provide a connecting member having excellent workability since alignment is not required.
[0006]
[Means for Solving the Problems]
According to the present invention, at least one surface of an adhesive layer having conductivity in the pressurizing direction composed of a conductive material and a binder has a melting temperature of 250 ° C. or lower and a tensile strength of 0.3 kgf. / mm ² or more, elongation provided base function-imparting insulating adhesive layer is not more than 300%, achieved by connecting members, characterized in that does not require a peelable substrate film was rolled scroll Is done.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be described with reference to the drawings.
1 to 3 are schematic cross-sectional views of a connecting member for explaining an embodiment of the present invention.
The connecting member of the present invention is a multilayer connecting member 3 in which a base material function-providing insulating adhesive layer 2 is formed on at least one surface of an adhesive layer 1 having conductivity in a pressurizing direction composed of a conductive material and a binder. The base material function-imparting insulating adhesive layer 2 needs to melt at the time of electrode connection, and the melting temperature is preferably 250 ° C. or lower.
Moreover, since the base material function-providing insulating adhesive layer 2 plays a role as a base material, it requires mechanical strength. Therefore, tensile strength at J1S-K6887 0.3kgf / mm ² or more, more preferably 1.0 kgf / mm ² or more, elongation of 300% or less, more preferably 100% or less.
The resin used as the base material function-imparting insulating adhesive layer is not particularly limited as long as it has an affinity with the conductive adhesive layer 1 and satisfies the above-mentioned conditions. , EVA copolymer, polyester, polyurethane and the like. As the conductive adhesive, a conductive material such as metal particles or plastic particles plated on the surface is dispersed in an insulating adhesive at a low concentration.
[0008]
As shown in FIG. 2, the base material function-imparting insulating adhesive layer 2 may be formed on both surfaces of the conductive adhesive layer 1. The presence of the base material function-providing insulating adhesive layer 2 on both surfaces makes it easier to set the tensile strength to 1.0 kgf / mm ² or more and the elongation to 100% or less. Further, when the connecting member is a sheet or a roll-shaped scroll, the possibility of transferring to the next connected connecting member is reduced. Furthermore, the conductive material is easily captured on the protruding electrodes, and the insulation between the electrodes is also kept good.
[0009]
As shown in FIG. 3, the conductive adhesive layer 1 may be formed on both surfaces of the base material function-providing insulating adhesive layer 2. In the case where there are alternately protruding electrodes, the conductive material is easily captured on the electrodes, and a good connection resistance is obtained.
Although not shown in FIGS. 1-3, you may add functions, such as adhesiveness, by making the base-material function provision insulation adhesive layer 2 into a multilayered structure further.
[0010]
An electrode connection structure using the connection member of the present invention will be described with reference to FIGS. FIG. 4 shows a structure in which the protruding electrode 7 formed on the substrate 6 and the planar electrode 8 of the glass substrate 6 ′ are connected via the connecting member of the present invention. That is, at least one of the electrode rows facing each other has a structure between the projecting electrode rows and is connected between the electrode rows facing each other. Moreover, the base material function-providing insulating adhesive layer 2 covers at least the protruding electrode 7 around the protruding electrode.
Here, the planar electrode 8 refers to a case where there is no unevenness from the surface of the substrate 6 ′ or even a few μm or less. When these are illustrated, the electrodes obtained by the additive method and the thin film method are typical.
FIG. 5 shows a case where the electrodes formed on the substrate are the protruding electrodes 7 and 7 ′. That is, it is a structure in which the both surfaces shown in FIG. 2 are connected via the connecting member having the base material function-providing insulating adhesive layers 2 and 2 ′. The base material function-imparting insulating adhesive layers 2 and 2 ′ cover the periphery of the protruding electrodes of the protruding electrodes 7 and 7 ′, respectively, and are in contact with the respective substrate surfaces.
4 to 5, examples of the substrate 6 include plastic films such as polyimide and polyester, composites such as glass epoxy, semiconductors such as silicon, and inorganic substances such as glass and ceramics. In addition to the above, the protruding electrode 7 can also include various circuits and terminals. The various electrodes shown in FIGS. 4 to 5 can be applied in any combination.
[0011]
In the connecting member of the present invention, the tensile strength of the base function-providing insulating adhesive layer 2 is 0.3 kgf / m ² or more, more preferably 1.0 kgf / mm ² or more, and the elongation is 300% or less, more preferably 100%. Therefore, the base material function-providing insulating adhesive layer 2 functions as a base material, and it is not necessary to peel off the base material at the time of temporary press-bonding. Is possible.
In addition, industrial waste such as Teflon and PET, which are conventionally used as base materials, is not generated, and is suitable for environmental protection. Further, from the viewpoint of workability and transportability, the connecting member can be a sheet or a roll-shaped roll.
[0012]
【Example】
EXAMPLES Next, although an Example demonstrates this invention, this invention is not limited to this.
Example 1
(1) Preparation of connecting member Phenoxy resin (high molecular weight epoxy resin) was extruded as a film forming material to obtain a base material function-imparting insulating adhesive layer having a thickness of 30 μm. Furthermore, in a 30% ethyl acetate solution with a ratio of 30/70 of a liquid epoxy resin (epoxy equivalent 185) containing a phenoxy resin and a microcapsule-type latent curing agent, polystyrene / particle diameter 5 ± 0.2 μm was added to Ni / 5% by volume of conductive particles on which a metal coating with a thickness of 0.2 / 0.02 μm of Au was added were mixed and dispersed. This dispersion was applied to the substrate function-imparting insulating adhesive layer with a roll coater and dried at 110 ° C. for 20 minutes to obtain a connection member having a thickness of 50 μm. The base material functionality-imparting insulating adhesive layer had a tensile strength of J1S-K6887 of 2.0 kgf / mm ² and an elongation of 80%.
(2) A double-layer FPC circuit board having a Cu circuit with a height of 38 μm on the connecting polyimide film (parallel circuit electrodes with a circuit pitch of 70 μm and an electrode width of 20 μm) and an indium oxide thickness of 0.2 μm on a glass of 1.1 mm ( The conductive adhesive layer was placed on the side of the planar electrode having a thin-film circuit having 1TO and a surface resistance of 20Ω / port. A Teflon film obtained by cutting the connection member in a roll shape into a width of 2 mm was placed, and temporary pressure bonding was performed with a metal tool at room temperature, a pressure of 0.5 MPa, and a connection time of 0.1 s.
The connecting member was able to be removed from the roll without transferring the conductive adhesive layer to the substrate function-providing insulating adhesive layer on the surface of the next layer roll, and could be temporarily pressure-bonded in a short time. Thereafter, the other circuit board and the upper and lower circuits were aligned and connected at 150 ° C., 20 kgf / mm ² , 15 s.
[0013]
(3) Evaluation When the cross section of this connection body was polished and observed with an electron microscope, it was a connection structure corresponding to FIG. The space between adjacent electrodes was free of bubbles and particles were spherical, but the particles were compressed and deformed on the electrodes and held in contact with the upper and lower electrodes.
When the opposing electrodes were evaluated as the connection resistance and the adjacent electrodes as the insulation resistance, the connection resistance was 1Ω or less and the insulation resistance was 10 ⁸ Ω or more. These showed almost no change after treatment at 85 ° C., 85%, RH 1000 hours, and showed good long-term reliability.
[0014]
Example 2
An EVA film (thickness: 30 μm, tensile strength 1.0 kgf / mm ² , elongation 90%) was used as the base material function-imparting insulating adhesive layer of Example 1, and a dispersion was applied to this film as in Example 1. A connection member was obtained. A connection body corresponding to FIG. 4 was obtained. When evaluated in the same manner as in Example 1, good connection characteristics were exhibited.
[0015]
Example 3
Although it was the same as that of Example 1, a base material function-imparting insulating adhesive layer was further formed on the other surface of the conductive particle layer to obtain a multilayer connection member having a three-layer structure in FIG. The FPCs of Example 1 were similarly connected to obtain a connection body corresponding to FIG. When evaluated in the same manner as in Example 1, good connection characteristics were shown.
[0016]
【The invention's effect】
As described above in detail, according to the present invention, a connecting member that does not use a base material, shortens the time of provisional pressure bonding, has no peeling problem of the base material, has high resolution, and has excellent connection reliability. An electrode connection structure and a connection method using this can be easily obtained.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view showing a connecting member of the present invention.
FIG. 2 is a schematic cross-sectional view showing another connection member of the present invention.
FIG. 3 is a schematic sectional view showing another connecting member of the present invention;
FIG. 4 is a schematic cross-sectional view showing an example of an electrode connection structure using the connection member of the present invention.
FIG. 5 is a schematic cross-sectional view showing an example of an electrode connection structure using the connection member of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Conductive adhesive layer 2 Base material function-providing insulating adhesive layer 3 Connection member 4 Conductive material 5 Binder 6 Substrate 7 Projection electrode 8 Planar electrode

Claims (1)

On at least one side of the adhesive layer having conductivity in the pressurizing direction composed of a conductive material and a binder, the melting temperature is 250 ° C. or less, the tensile strength is 0.3 kgf / mm ² or more, and the elongation is A connecting member characterized by being provided with a base material function-imparting insulating adhesive layer of 300% or less and not requiring a peelable base film as a roll-shaped roll .

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