JPH0218554B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for manufacturing an elastic connector, and is particularly suitable for various precision electronic circuits that require a low conduction resistance value. The present invention relates to a method of manufacturing an improved elastic connector.

[Prior art] In recent years, with the miniaturization of electronic components and circuits, multilayer connectors in which conductive rubber and insulating rubber are alternately laminated, and conductive wires in insulating rubber have been developed as connectors for interconnecting these components. Connectors in which conductive wires are arranged in isolation from each other and pass through insulating rubber in the thickness direction are widely used in electronic watches, cameras, and calculators. Each of these connectors has subtle characteristics such as the same pain resistance value and the fineness of the electrode group that can be connected.The resistance value depends on the dimensions of the electrodes to be connected and the distance between the electrodes, but Laminated connector for watches, 50~ per connected electrode
5000Ω, a conductive wire penetrating connector used for connection between circuits of cameras, etc., and has a conductive resistance value of 0.2 to 10Ω per connected electrode.

[Problems to be Solved by the Invention] These connectors have achieved the purpose of connecting a liquid crystal display and a circuit board, or a circuit board for small current signals, but they are not suitable for connecting a driving circuit board, for example. It has not been possible to sufficiently meet the demand in fields that require low electrical conduction resistance, such as connection of circuits using LSI (Large-Scale Integrated Circuits) high-speed arithmetic elements, and product function inspection of LSI chip carriers and flat packs. .

The present invention was created in view of this background,
The purpose is to provide a method for manufacturing a connector that is capable of making fine pitch connections and has a lower resistance value than conventional connectors, which is suitable for the above-mentioned fields that require a low resistance value.

[Means for Solving the Problems] The object of the present invention is achieved by the following configuration.

(1) A method for manufacturing a low-resistance elastic connector, which comprises at least the following steps.

The process of aligning multiple ferromagnetic materials in a certain direction, solidifying them with resin, cutting them into a predetermined length, and then removing the resin to obtain a filament; electroless coating on the entire surface of the filament. A process of coating a good conductor by plating or vapor deposition, a process of adhering an uncured elastomer to the filament coated with a good conductor, applying a magnetic field to the above mixture to align the filaments in the thickness direction, and then applying an uncured elastomer to the filament. The process of curing elastomer.

(2) The method for manufacturing a low-resistance elastic connector according to the above item, characterized in that the electroless plating process is performed twice for copper and gold in that order.

The ferromagnetic material used in the present invention includes:
Examples include iron, stainless steel, nickel, and cobalt.

Hereinafter, the manufacturing method of the present invention will be explained with reference to the accompanying drawings.

In the present invention, first, a plurality of ferromagnetic wires as described above are aligned in a certain direction and hardened with resin.
A structure 1 as shown in Fig. 1 is manufactured, cut into a predetermined length to form a thin piece 2 having a predetermined fiber length as shown in Fig. 2, and then the resin is melted. Create a short striatum.

Next, the entire surface of each of these filaments is coated with a good conductor by electroless plating or vapor deposition. FIG. 3 is an enlarged vertical cross-sectional view of a good conductor-covered filament 5 obtained by coating a filament 4 constituting a core material with a good conductor 3, and FIG. 4 is a cross-sectional view thereof. The reason for using a ferromagnetic material and a highly conductive conductive material here is to use ferromagnetism to magnetically orient and align the conductive material dispersed in ^the uncured elastomer. It becomes possible to bury three or more conductive filaments at a high density.

Examples of good conductors used to coat the surface of the ferromagnetic filament include metals with good conductivity such as gold, copper, and silver.

Electroless plating is suitable for plating a good conductor over the entire surface of a short filament. It is also preferable to coat the film with a good conductor by vapor deposition instead of electroless plating.

Preferably, on the surface of the ferromagnetic material, a thick film layer of 1 μm or more of copper, which is relatively inexpensive and has excellent conductivity, is formed. More preferably, the core material is iron (e.g. stainless steel) with excellent mechanical strength,
A conductive filament is one in which the entire surface of the core material, including the terminals, is coated with a thick film of 1 μm or more of copper, which has excellent conductivity, and the surface of the thick copper film is further coated with gold, which has excellent environmental resistance. It is best to use it as

As for the thickness of the filamentous body constituting the core material, there is no problem as long as it is 50μ or less, and a thickness of 25μ or less is preferable from the viewpoint of compression characteristics as an elastic connector, but it is not limited to this.

An uncured elastomer is then applied to the conductor coated filament.

FIG. 5 shows one embodiment thereof. In the figure,
5 is a good conductor coated filament, 6 is a film, and 7 is a frame. A mixture of an uncured elastomer 8 and a good conductor coated filament 5 is poured into the space formed by 6 and 7 to produce a capsule 9. .

Subsequently, a magnetic field is applied to the mixture to align the filaments in the thickness direction, and then the uncured elastomer is cured to obtain a predetermined low-resistance elastic connector.

FIG. 6 shows one embodiment thereof. That is, when the capsule 9 is placed in the magnetic field formed by the magnetic pole 10, the good conductor coated filament 5 having a ferromagnetic material is oriented in the direction of the lines of magnetic force.

The uncured elastomer 8 is cured with the filament 5 oriented in a certain direction, and then the film 6 and the frame 7 are removed to obtain an anisotropic conductive sheet 12 as shown in FIG. . Here 1
1 is an uncured elastomer 8 that has been cured.

The anisotropic conductive sheet 12 is cut into a predetermined size to obtain a low resistance elastic connector 13.

As the electrically insulating elastomer used in the present invention, various elastomers such as silicone rubber, nitrile rubber, butyl rubber, and natural rubber can be used, but silicone rubber is most preferable from the viewpoint of temperature stability, weather resistance, change over time, etc. .

The buried density of the filament is at least 1 mm ² based on the connection density and resistance value generally required for connectors.
The density is preferably 3 or more, preferably 8 or more, more preferably 15 or more. The length of the striatum is preferably equal to or slightly longer than the length of the insulating matrix. More preferably, the filaments protrude from the elastomer surface by 3 to 50 microns to ensure the reliability of the electrical connection. The thickness of insulating elastomer is generally 0.3 mm due to the absorption of tolerances of related parts and compactness.
~5 mm is used.

In the present invention, when the conductive linear body is coated with a noble metal such as gold, it is economically advantageous to limit the coated portion to the portion exposed from the insulating elastomer. Further, the density at which the ferromagnetic material is magnetically oriented and buried is preferably 200 or less, preferably 100 or less per mm ² when using filaments of around 25 μm from the viewpoint of entanglement of the filaments. on the other hand,
The above-mentioned fields that require low resistance connectors are at least 0.1Ω or less per connection electrode, preferably
It is about 0.02Ω, and the volume specific resistance value R is 0.01Ω・
cm, more preferably 0.005 Ωcm, is a conductivity level that satisfies these requirements and is made possible for the first time by the present invention.

The industrial manufacturing method of the present invention is as follows.

First, the core material is aligned in a certain direction, solidified with resin and cut, and then the resin is melted to create short filaments with uniform length. Next, the ferromagnetic and electrically conductive filaments of uniform length are mixed into the uncured elastomer stock solution to produce a sheet-like capsule of a predetermined thickness. This capsule is a space in which the above-mentioned mixture is filled into a space whose upper and lower sides are made up of thin films made of polyester film or the like and whose outer periphery is made up of a frame. By curing the capsules in a magnetic field essentially perpendicular to the capsules, an anisotropically conductive sheet in which the filaments are oriented in the thickness direction of the sheet is obtained. In order to obtain a highly accurate sheet thickness, it is preferable to perform pressure molding while applying a magnetic field.

The volume resistivity value in the present invention was measured by the following method.

The electrode plate used was one in which copper electrodes (thickness: 35 μm) were formed on an epoxy substrate mixed with glass fiber, and the surface was gold-plated with dimensions of 1 mm x 1 mm. It contracted by 5% and was clamped. Thereafter, a DC voltage of 1 mV was applied between the electrodes, and the resistance value was measured using a digital multimeter.

[Effects of the Invention] According to the present invention, it is possible to obtain an elastic connector with extremely low resistance, and this makes it possible to use an elastic connector which conventionally cannot be used due to its high resistance value and is connected by bonding. can contribute to improvements in the field of development.

This is especially true when there are problems with connections using the bonding method, such as when it is necessary to remove the bonding again after testing LSI product functionality, or when ceramic carriers and resin circuit boards have significantly different coefficients of thermal expansion, making it difficult to maintain reliability against temperature changes. The field where the present invention makes a large contribution is the case where the performance is low.

[Example] Example 1 Stainless steel long fiber (diameter 25μ) as ferromagnetic material
After aligning multiple books in a certain direction using
The bundled fiber bundle is placed in a polyamide resin, the resin is attached to the fiber bundle, the fiber bundle is taken out, heated, and left for a considerable period of time to harden the resin. Next, this fiber bundle is cut into a predetermined length, and then placed in methanol to dissolve the resin attached to the fiber bundle to obtain a filament.
Subsequently, the filament was surface activated with palladium, the entire surface was plated with copper to a thickness of 1μ, and this was further covered with nickel.
On top of that, 0.3μ gold plating was applied. All of these platings were performed by electroless plating, and copper was treated at room temperature using a chemical solution containing 12.5% by weight of Cu and 12.5% by weight of caustic soda. Nickel was treated at 80°C using a chemical solution containing 0.5% by weight of Ni, and gold was treated at 95°C using a chemical solution containing 0.3% by weight of Au. Thereafter, the linear bodies were mixed in a silicone rubber stock solution at 3% by weight of the silicon weight, and a magnetic field of 5000 Gauss was applied to form the linear bodies, and the linear bodies were oriented at a density of 5 pieces ^per 1 mm2, and the buried thickness was An anisotropic conductor of 1 mm in size was obtained and cut to obtain an elastic connector with a width of 2 mm, a length of 20 mm, and a thickness of 1 mm. As a result of measuring the connector using the above-mentioned measuring method using 1 mm square electrodes, the electrical resistance value between the electrodes R ₀ = 0.010Ω, and the volume specific resistance value R =
We obtained an elastic connector with a resistance value of 0.0010, which is comparable to that of bonding.

[Brief explanation of drawings]

Figure 1 shows a structure obtained by aligning multiple ferromagnetic wires in a certain direction and hardening them with resin, Figure 2 shows a thin piece obtained by cutting the structure to a predetermined length, and Figure 3 4 is an enlarged vertical cross-sectional view of a good conductor-covered filament, FIG. 4 is a cross-sectional view thereof, and FIG. 5 is a schematic longitudinal cross-section showing an example of a capsule containing a mixture of a good conductor-coated filament and an uncured elastomer. , FIG. 6 is a diagram illustrating a method for orienting a good conductor coated filament, and FIG. 7 is a schematic perspective view showing an example of the obtained anisotropically conductive sheet.
FIG. 8 is a schematic perspective view showing an example of a low resistance elastic connector obtained by the method of the present invention. 1: Structure, 2: Thin piece, 3: Good conductor, 4: Wire body, 5: Good conductor coated filament body, 6: Film, 7:
Frame body, 8: uncured elastomer, 9: capsule,
10: Magnetic pole, 12: Anisotropic conductive sheet, 13: Low resistance elastic connector.

Claims (1)

[Scope of Claims] 1. A method for manufacturing a low resistance elastic connector, comprising at least the following steps. The process of aligning multiple ferromagnetic materials in a certain direction, solidifying them with resin, cutting them into a predetermined length, and then removing the resin to obtain a filament; electroless coating on the entire surface of the filament. A process of coating a good conductor by plating or vapor deposition, a process of adhering an uncured elastomer to the filament coated with a good conductor, applying a magnetic field to the above mixture to align the filaments in the thickness direction, and then applying an uncured elastomer to the filament. The process of curing elastomer. 2. The method for manufacturing a low resistance elastic connector according to claim 1, characterized in that the electroless plating process is performed twice for copper and gold in that order.