JP2000021470A - Conductive member and low compression/low resistance connector using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To hold satisfactory electrically continuos state in a small pressing load by the connection at a low pitch with a base board of a small electrode pitch by respectively blending metallic particles and conductive fiber of a specific quantity with the specific quantity of an insulating elastomer resin. SOLUTION: In this conductive member 1, metallic particles 3a, 3b composed of a group of the large/small two particle sizes and conductive fiber 4 are dispersed uniformly through an insulating elastomer resin 2, and the mutual metallic particles or the metallic particles and the conductive fiber make contact easily with and connected to each other at compressing. In this case, the conductive member 1 is formed by blending 50 to 200 pts.wt. of the metallic particles and 30 to 150 pts.wt. of the conductive fiber with 100 pts.wt. of the insulating elastomer resin. The metallic particles are composed of fine particles having the average particle size of 2 to 3 μm and coarse particles having the average particle size of 30 to 100 μm, a blending rate of the fine particles and the coarse particles falls within a range of 20/80 to 50/50 in the weight ratio, and the conductive member is formed as a structure that the mutual metallic particles or the metallic particles and the conductive fiber are easily contacted with and connected to each other at compression time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conductive member having a small volume resistivity and elasticity, for example, as a movable contact of a push button switch of a cellular phone or the like, and a connection between a glass substrate and a circuit substrate in a liquid crystal display. Connection between circuit boards, IC
The present invention relates to a conductive member used for electrical connection or the like of an inspection device such as a chip, and a low-compression low-resistance connector using the same.

[0002]

2. Description of the Related Art Conventionally, connectors for connecting electronic devices include:
A so-called zebra in which a conductive rubber layer containing carbon black powder and an insulating rubber layer are alternately multiplexed or a conductive rubber layer filled with a large amount of metal particles and an insulating rubber layer are alternately multiplexed. A type connector and an anisotropic conductive connector in which a plurality of thin metal wires are arranged in an insulating rubber layer in a thickness direction are used.

However, in the connector containing the carbon black powder, the conductive member forming the conductive layer has a high volume resistivity, so that a connector such as a color liquid crystal module or a black and white 16 or more gray scale liquid crystal module is used. A current of 10 mA or more flows in connections that require low resistance, connections that want to minimize variations in connection resistance between terminals, or connections with circuit boards that require high current values, such as plasma display modules. The connector was not suitable as a connector because the connector generated heat and a temperature rise occurred. In addition, a connector filled with a large amount of metal particles has a low volume resistivity as a conductive member but has a high hardness, and a stable connection cannot be established unless a high compression load is applied when connecting. There has been a problem that the substrate and circuit components are damaged due to distortion. Furthermore, when the conductive rubber layer and the insulating rubber layer are laminated alternately in multiple layers and molded, unless high pressure is applied, the metal particles do not contact each other, and the original low volume resistivity cannot be obtained. There were restrictions on processing conditions, processing equipment, and the like.

On the other hand, in an anisotropic conductive connector in which a plurality of thin metal wires are arranged in the thickness direction, the thin metal wires are easily buckled by the compressive force at the time of connection, so that they cannot be used for an inspection device used repeatedly; In order to completely connect the thin metal wires, it is necessary to compress the entire connector with a high pressure, which increases the load on the terminals of the IC chip and the inspection device;
Since the connection end surface of the thin metal wire is not a uniform and smooth surface, point contact is likely to occur, resulting in poor contact; in order to reduce the contact resistance as much as possible, the tip of the thin metal wire or the thin metal wire itself needs to be plated with gold, which reduces the manufacturing cost. Bulky; etc.

[0005]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a low volume resistivity, a stable resistance value,
A conductive member capable of flowing a large amount of current, and a low compression and low resistance connector using this conductive member that can be connected to a substrate having a small electrode pitch at a low pitch and maintain a good conductive state with a small pressing load. To provide.

[0006]

The conductive member of the present invention is characterized in that 50 to 200 parts by weight of metal particles and 30 to 150 parts by weight of conductive fiber are blended with 100 parts by weight of an insulating elastomer resin. The metal particles have an average particle size of 2 to 3 μm
Of fine particles and coarse particles having an average particle diameter of 30 to 100 μm, and the mixing ratio of the fine particles and the coarse particles is 20 / weight ratio.
It is preferable that the metal particles be in the range of 80 to 50/50 and have a structure in which the metal particles or the metal particles and the conductive fibers are easily contacted and connected at the time of compression. A low-compression low-resistance connector using this conductive member is obtained by alternately laminating conductive layers made of a conductive member and insulating layers made of an insulating elastomer resin (hereinafter abbreviated as insulating layers).

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a conductive member of the present invention and a low-compression low-resistance connector using the same will be described with reference to the drawings. FIG. 1 is a schematic vertical cross-sectional view of a conductive member used in the present invention. The conductive member 1 has metal particles 3a and 3b having two groups of large and small particle sizes in an insulating elastomer resin 2.
And the conductive fibers 4 are uniformly dispersed, so that the metal particles or the metal particles and the conductive fibers are easily contacted and connected at the time of compression. FIGS. 2 and 3 are perspective views showing different aspects of the low-compression low-resistance connector of the present invention. The low-compression low-resistance connector 5a of FIG. 6, and a low-compression low-resistance connector 5b shown in FIG. 3 is insulated on both left and right sides of the zebra-shaped main body. A side member 8 composed of a layer 7 is provided.

The insulating elastomer resin 2 used as the base material in the conductive member 1 of the present invention may be any elastic material which is stable in shape and deforms significantly by its own weight and does not undergo plastic deformation after curing. Natural rubber, butadiene styrene, acrylonitrile butadiene, acrylonitrile butadiene styrene, styrene ethylene styrene, ethylene propylene, copolymer rubbers such as ethylene propylene diene, chloroprene rubber, silicone rubber, butadiene rubber , Synthetic rubbers such as isoprene rubber, chlorosulfonated polyethylene rubber, polysulfide rubber, butyl rubber, fluorine rubber, urethane rubber, polyisobutylene rubber, thermoplastic elastomers such as polyester elastomers, plasticized vinyl chloride resin,
Examples include vinyl acetate resin and vinyl chloride / vinyl acetate copolymer resin. Among these, they are excellent in aging characteristics, electrical insulation, heat resistance, compression set, workability, etc., and are stable in price. Silicone rubber is preferred.

As the silicone rubbers, polysiloxanes such as dimethyl-, methylphenyl-, methylvinyl- and the like, and halogenated polysiloxanes which are imparted with appropriate rheological properties by blending fillers such as silica are generally used. Or halogenated polysiloxanes which have been vulcanized or cured with metal salts.

The metal particles 3 to be mixed with the insulating elastomer resin 2 only need to have at least a surface coated with a metal, such as gold, silver, copper, nickel, cobalt or stainless steel. , Spherical or flake-like particles consisting of a single metal such as brass, or thermosetting resins or thermoplastic resins such as phenolic resins, epoxy resins, silicone resins, and urethane resins, their baked products, carbon, ceramics, glass, etc. A powder obtained by using a powder of an inorganic material or the like as a core material and coating the surface of the powder with the metal by a method such as plating, vapor deposition, sputtering, or CVD, or a mixture of two or more of the above particles.

The amount of the metal particles is 50 to 200 parts by weight based on 100 parts by weight of the insulating elastomer resin. This is
If the amount is less than 50 parts by weight, it is difficult to establish connection and conduction between the metal particles or the metal particles and the conductive fibers at the time of compression, and a stable resistance value cannot be obtained. No improvement is required ( ^10-2 to ^10-4 Ωcm is no problem), and the hardness of the conductive member is rather high, so that it is difficult to connect the obtained connector with low compression.

The metal particles have an average particle size of 2 to 3 μm.
Of fine particles and coarse particles with an average particle size of 30 to 100 μm. The compounding ratio of fine particles and coarse particles is within the range of 20/80 to 50/50 by weight. Preferably, there is. This is because if the compounding amount is increased to achieve conduction between the particles by only one kind of particle size, the hardness of the conductive member becomes high and it becomes difficult to process, but when fine particles and coarse particles are used together, Since the other particles are filled between the one particles, conduction can be achieved with a small blending amount. As a result, a conductive member which does not have high hardness and is easy to process can be obtained. In particular, when the mixing ratio of the coarse particles is increased to connect the coarse particles with the fine particles as described above, the hardness is not increased, and the conductivity is easily increased. However, outside the above range, it is not preferable because conduction at the time of low compression cannot be obtained and hardness becomes high.

The conductive fiber 4 blended with the metal particles
It is sufficient that at least the surface is coated with metal.For example, copper, copper alloy, stainless steel,
Metal wires such as tungsten, nickel, and solder alloys; methods such as plating, vapor deposition, sputtering, and CVD of the surface of inorganic fibers such as carbon fibers, ceramics, and glass fibers and various natural or synthetic fibers with the above metals, particularly gold. And the like. These may be those subjected to rust prevention treatment in order to improve environmental resistance.

[0014] These conductive fibers are blended with metal particles in an insulating elastomer resin to facilitate connection between metal particles, do not require high pressure for compression when formed into a connector, and are commonly used. Since the cost can be reduced by using fibers of a certain shape, the diameter is 2 to 500 μm
Preferably, it is 10 to 100 μm and has a length of 0.1 to 20 mm, particularly 1 to 10 mm, and more preferably 3 to 5 mm.

The amount of the conductive fibers to be added to 100 parts by weight of the insulating elastomer resin must be 30 to 150 parts by weight because the resistance value is low and a stable connection can be achieved even at a low compression. If this is less than 30 parts by weight, the connection continuity with the metal particles is insufficient and the desired resistance value cannot be obtained, and
If it exceeds 150 parts by weight, the volume resistivity will be sufficiently small, but the hardness of the conductive member will be high, and it will be difficult to obtain a stable resistance value with low compression. If it is obtained, warpage of the substrate, partial peeling of the circuit pattern, and internal destruction when fixing the electronic component are likely to occur.

The conductive member 1 of the present invention comprises an open roll,
It can be obtained by uniformly dispersing the metal particles 3 and the conductive fibers 4 in the insulating elastomer resin 2 using a kneading / dispersing device such as a three-roller or a crusher. For the purpose of improving various physical properties such as heat resistance, anti-aging property, tensile strength, compression set, and workability, various additives and a reinforcing agent such as silica may be added.

In the above-mentioned zebra-shaped low-compression low-resistance connector 5a, the insulating material forming the insulating layer 7 may be the same as the insulating elastomer resin 2 described above.
The insulating material may be the same as or different from the insulating material used in manufacturing the conductive member, but the conductive layer 6 and the insulating layer 7 must be tightly integrated so as not to be separated from each other. It is preferable that these are made of the same material.

The hardness of the low-compression low-resistance connector is 40 to 80.
° H, particularly preferably 50 to 70 ° H, so that even if metal particles or conductive fibers are mixed, it is the same as a generally used connector having a carbon-based conductive layer. % Connection is possible, and a stable and stable connection state can be easily obtained.
The load on the electronic component is reduced, and the size and weight of the inspection device such as the IC chip inspection are reduced.

The low-compression low-resistance connector is manufactured by various methods such as a printing method and a calendar method. However, in consideration of stable productivity, a method of manufacturing by stacking a conductive layer and an insulating layer by a calendar method. Is preferred. An example will be described in detail. An insulating elastomer resin is formed into a thin film with a calender on a polyethylene terephthalate film, provided with heat and cured to form an insulating layer, and then a conductive member is calendered on the insulating layer. A conductive layer is formed by forming a thin film, and the polyethylene terephthalate film is peeled off from the obtained sheet to obtain a laminated sheet. After obtaining a large number of laminated sheets by repeating this step, these are laminated in the same order to form a laminated block body, and vulcanization treatment is performed. This is sliced in a direction crossing the lamination surface to obtain a sheet in which conductive layers and insulating layers are alternately arranged in a streak shape. After secondary vulcanization of the sheet, the sheet is cut at a predetermined width across the conductive layer and the insulating layer to obtain the low compression low resistance connector of the present invention.

In the case of the low-compression low-resistance connector shown in FIG. 3 in which side members 8 are provided on both left and right sides of the zebra-shaped main body, the thickness and the material may be different between the main body portion and the side members. . In this low-compression low-resistance connector, when the compression load of the zebra-shaped body is high, it can be obtained by using a side member made of a low-hardness insulating rubber having a rubber hardness of 50 ° H, particularly 40 ° H or less. The compression load of the low compression low resistance connector as a whole can be reduced.

[0021]

The present invention will be more specifically described below with reference to examples and comparative examples. Example 1 An insulating silicone rubber KE971U (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.) was formed on a polyethylene terephthalate film having a thickness of 100 μm as a base film.
Separate with a calender to form a 50μm thin film, 200
The resultant was introduced into a heating furnace at a temperature of ° C. and cured to form an insulating layer. On the other hand, two kinds of silver particles having an average particle size of 2 μm and an average particle size of 50 μm were mixed with 100 parts by weight of the same insulating silicone rubber in a weight ratio of 30:
A mixture of 150 parts by weight of mixed silver particles obtained by blending at a ratio of 70 and heat-treated at 150 ° C. for 30 minutes, and 100 parts by weight of a conductive fiber obtained by applying gold plating to a brass wire having a diameter of 30 μm and a length of 10 mm was mixed. A conductive member was prepared by kneading. The conductive member was calendered on the insulating layer so as to form a thin film having a thickness of 50 μm, and the conductive layer was laminated and formed. The base film was peeled off to obtain a laminated sheet. After obtaining a large number of laminated sheets in the same procedure, they were laminated in the same order to form a laminated block, and after vulcanization, sliced in a direction crossing the laminated surface. After secondary vulcanization, the hardness is 60 ° H (JIS
K 6391) to obtain a sheet in which conductive layers and insulating layers are alternately arranged in a streak shape,
By cutting at a predetermined width across the conductive layer and the insulating layer, a low-compression low-resistance connector of the present invention was obtained.

Example 2 A low-compression low-resistance connector according to the present invention was obtained in the same manner as in Example 1, except that the amount of the mixed silver particles was changed to 80 parts by weight.

Comparative Example 1 A low-resistance connector was obtained in the same manner as in Example 1, except that the amount of the mixed silver particles was 500 parts by weight and no conductive fiber was used.

Comparative Example 2 A low-resistance connector was obtained in the same manner as in Example 1, except that the mixing ratio of the two kinds of silver particles was 10:90.

Comparative Example 3 A low-resistance connector was obtained in the same manner as in Example 1, except that the mixing ratio of the two kinds of silver particles was changed to 60:40.

For each connector manufactured in each of the above Examples and Comparative Examples, gas generation, vulcanization delay and volume resistivity were measured by the following methods, and comprehensive judgment was made based on these results. The hardness, connection reliability, and compression load were measured by the method, and the results are shown in Table 1.

(Specifications of the above test method) Gas generation: 165 ° C. under a pressure of 200 kg / cm ^{2 by} a press machine
For 10 minutes, and the state of gas generation during that time was examined. The case where no gas was generated was evaluated as ○.

Vulcanization delay: AS using ASTM-100 oscillating disc rheometer (manufactured by Toyo Seiki Seisakusho)
The vulcanization characteristics were measured according to the method of TM-D-2084. The case where the time difference was less than 20 seconds compared with the vulcanization time of the insulating elastomer to which the conductive material was not added was evaluated as ○.

Volume resistivity: SRIS-230 by voltage / current method
The measurement was carried out according to the method described in 1, and a value lower than 10 ⁻² Ωcm was defined as “good”.

Connection reliability: electrode pitch 0.5 mm, thickness
Conduction resistance is measured with the connector compressed by 10%, sandwiched between 1.6mm boards, and the conduction resistance is 250mΩ in a stable state.
In the following, the case where the current value can be flowed up to 200 mA and there is no warpage or damage of the substrate is indicated by "O", and the case where it is not such is indicated by "X".

Compressive load: 5 to 8 kg load at 10% compression
Less than / cm ^{2 was} defined as “small” and more than that was defined as “large”.

[0032]

[Table 1] As shown in Table 1, the low-compression low-resistance connectors of Examples 1 and 2 of the present invention exhibited no gas generation or vulcanization delay, low compression as a connector, and practical low resistance.

[0033]

The low-compression low-resistance connector of the present invention has a small variation in resistance value, can provide a stable connection, and can flow a small current, so that it can be connected to a color liquid crystal module, a plasma display module, or the like. It can be suitably used, and can be used in a circuit requiring a high current value in a sufficiently stable state. Moreover, since the compression ratio at the time of connection can be reduced, when used for connection at the time of inspection of an IC chip, etc., the deformation of the terminal of the IC chip and the destruction inside the chip are prevented, and the load applied to the inspection equipment is reduced. In addition to performing more accurate inspection, the size and weight of the inspection device can be reduced. Furthermore, it can be manufactured with existing equipment, and the productivity is high and the manufacturing cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic longitudinal sectional view of a conductive member used in the present invention.

FIG. 2 is a perspective view showing one embodiment of the low compression low resistance connector of the present invention.

FIG. 3 is a perspective view showing another embodiment of the low compression low resistance connector of the present invention.

[Explanation of symbols]

1: conductive member, 2: insulating elastomer resin, 3a: fine metal particles,
3b: coarse metal particles, 4: conductive fiber,
5a, 5b: low compression low resistance connector, 6: conductive layer,
7: insulating layer, 8: side material.

Claims (3)

[Claims] 1. A conductive member comprising 100 to 100 parts by weight of an insulating elastomer resin, 50 to 200 parts by weight of metal particles and 30 to 150 parts by weight of conductive fibers. 2. The metal particles are composed of fine particles having an average particle diameter of 2 to 3 μm and coarse particles having an average particle diameter of 30 to 100 μm, and the mixing ratio of the fine particles and the coarse particles is 20/80 to 50 /
2. The structure according to claim 1, wherein the metal particles are in contact with each other or between the metal particles and the conductive fibers during compression.
The conductive member as described in the above. 3. A low-compression low-resistance connector in which conductive layers made of the conductive member according to claim 1 and insulating layers made of an insulating elastomer resin are alternately laminated.