JPH0332237B2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to electrical and electronic components (hereinafter simply referred to as components),
In particular, electric and electronic components with substrates such as resistors, diodes, transistors, capacitors, and ICs connected to printed circuit boards, extraction electrode substrates of liquid crystal display devices (hereinafter simply referred to as substrates), etc. via anisotropic conductive adhesive films. It is related to.

(Prior technology) Connections between electrode terminals of components and connecting terminals arranged on the board from which signals are to be sent in and out are usually made by soldering, or by dispersing and mixing conductive particles in an insulating adhesive. There are known adhesives that use anisotropically conductive adhesives that are conductive in the thickness direction but insulating in the planar direction (see Japanese Patent Publication No. 59-2179). It is connected to and mechanically held and fixed. Anisotropic conductive adhesives are often used because they are easy to use, but they generally have weak adhesive strength and may peel off due to movement during the process or shock from vibrations of the finished product, and they also have poor heat resistance and moisture resistance. However, it is difficult to connect the parts with an anisotropic conductive adhesive and then cover the parts with an insulating adhesive, which increases the number of parts and processes, and if the parts have different shapes. has the disadvantage that this process becomes even more complex and, as a result, more expensive.

(Structure of the Invention) The present invention relates to a board-attached component that solves the above-mentioned disadvantages.This invention relates to an electrode terminal of an electrical/electronic component inserted through the opening of a container provided with a flange, and a circuit to be connected to the component. The connection terminal of the board is
They face each other through an anisotropically conductive adhesive film that has conductivity only in the film thickness direction, and the area around the connection terminal of the circuit board becomes a movable strip due to the slit surrounding the connection terminal, which insulates the flange and the circuit board. It is characterized by being bonded and held by an adhesive.

That is, as a result of various studies on how to firmly bond and connect components and substrates, the inventors of the present invention found that the components were placed in a container with an opening and a flange around the container, and the electrode terminals were placed on the opening side. The electrode terminal is adhesively connected to the connection terminal of the substrate via the anisotropic conductive adhesive film, and the flange portion is adhesively fixed to the substrate with an insulating adhesive.
At that time, if the pressure is constantly applied between both terminals when bonding, a reliable and strong bond between the component and the board can be obtained. In this case, the board expands and the electrode terminals of the component and the connection terminals of the board become opposed to each other, which tends to cause poor contact and incorrect connections.However, by providing the slits as in the present invention, this misalignment due to thermal expansion can be avoided. The present invention was completed after confirming that it could be significantly reduced.

Examples of components used in the present invention include conventionally known components such as resistors, diodes, transistors, capacitors, and ICs.

These parts usually have several lengths, widths, and depths.
In most cases, the diameter is about mm to several cm, but there is no particular limitation in the present invention. Examples of the shape include cubes, rectangular parallelepipeds, and cylindrical shapes, but because they are adhesively fixed to the substrate, cubic and rectangular parallelepipeds with flat electrode surfaces are often used and preferred. There is. In the present invention, the board becomes a movable strip due to the slit (notch) provided in the board around the connection terminal, and is highly independent and flexible, so it can easily follow unevenness on the electrode terminal side. , can be used without necessarily being particular about this. Although leadless types are generally used, leaded types can also be used.

The component of the present invention is inserted into a container having an opening and a flange around the periphery so that the electrode terminal is located on the opening side, but the shape of the flange can be arbitrary. In order to increase the adhesive force, the opening may have a wide area in front of the periphery thereof, or may have an interrupted structure. This container is made of polystyrene, polyester, polycarbonate,
It is preferable to use an organic polymer material such as polyacrylate, polyimide, or polyamide to form a film by vacuum forming, pressure forming, press forming, or the like.

On the other hand, the substrate used in the present invention may be a conventionally known substrate, such as a substrate on which a desired circuit is printed on an insulating substrate, or a substrate on which a metal foil is etched using a known method. The connection terminal may be attached or baked by photo-etching, including the connection terminal, but this connection terminal part should be designed to follow the undulations and unevenness of the electrode terminal of the component, or to absorb vibrations received after it is fixed with adhesive. In order to obtain reliable conduction, use flexible materials such as heat-resistant polyester film, polyimide film, etc. for at least the connection area.
Preferably, it is made of plastic film with excellent electrical properties.

Further, there is no particular limitation on the anisotropic conductive adhesive for electrically connecting the component and the substrate used in the present invention. Therefore, this material is made of insulating adhesives such as thermosetting, thermoplastic, ultraviolet curable, electron beam curable, and anaerobic, as well as metal particles such as gold, silver, palladium, nickel, tin, tungsten, and solder alloys. 5 to 30 parts by volume of short metal fibers, ceramic particles such as MoSi ₂ , WC, TiC, carbon fibers, carbon particles, plastic balls with a conductive coating on the surface, etc., were added to 100 parts by volume of the adhesive. Just take it as a thing. However, when insulating adhesives used in anisotropic conductive adhesives are of the reactive curing type, they generally have strong adhesive strength but have a short pot life and tend to take a long reaction time; Thermoplastic materials tend to require a short operation time but have low adhesive strength, so it is preferable to select an appropriate material depending on the purpose in terms of workability, adhesive strength, and cost. Note that this anisotropic conductive adhesive film is usually applied in liquid form onto the circuit board.
It may be present as a thin film on the substrate, but it may also be a film-like solid substance, in which case it is placed on the substrate and heated and pressurized as necessary. Bye.

Next, the substrate-attached component of the present invention will be explained in detail based on the accompanying drawings.

FIG. 1 is an exploded perspective view of a substrate-attached component A of the present invention, and a rectangular parallelepiped component 1 having an electrode terminal 2 is
The electrode terminal 2 is placed tightly into a container 3 having an opening 4 and a flange 5, which is formed in a shape that prevents any movement inside the container 3, with the electrode terminal 2 facing the opening. Ru. This container 3 is attached to a circuit board. A slit 8 is provided in the peripheral circuit board surrounding the connection terminal 7, and a flange portion 5 large enough to be sufficiently adhesively fixed onto the circuit board 6 is sealed with an anisotropic conductive adhesive. When crimped through the thin film 9, the electrode terminal 2 of the component 1 and the connection terminal 7 of the board 6 are electrically adhesively connected, and furthermore, the flange portion 5 of this container 3 is firmly bonded to the circuit board with an insulating adhesive. Since the terminals 2 and 7 are fixed, the electrical connection between the two terminals 2 and 7 is made through the electrode terminal 7.
The fact that the surrounding substrate is made into a movable strip by means of the slits 8 has the advantage that the connection between the two terminals is reliable and strong. In addition, when storing this part 1 in the container 3, please be aware that the adhesive may loosen during pressure bonding (flow and become thinner),
In order to prevent the electronic component 1 from lifting up from the substrate 6 due to changes over time after being adhesively fixed, for example, as shown in FIG. As shown in FIG.
It is preferable to provide the following.

(Example) Next, examples of the present invention will be given.

Example 1 As shown in the bottom view of FIG.
As shown in FIG. 5, the IC 12 which is J-bent is mounted in a container 14 having a flange portion 15 obtained by molding a 0.3 mm thick film made of a copolymer resin of ABS and polycarbonate. I entered.
Next, a 25 mm thick polyimide film-based flexible board (copper foil thickness 1/
2 oz/ft ² (surface gold plating treatment) 16, the peripheral part of the connecting terminal 17 facing the electrode terminal 13 of the IC 12 is made into a movable strip by the slit 18, and on this,
Ultraviolet curable liquid insulating adhesive with particle size 10~
A thin coating film 19 with a thickness of 40 μm was formed by screen printing an anisotropic conductive adhesive in which 30 μm silver-copper alloy (containing silver and copper at a ratio of 8:2) particles were dispersed and mixed in an adhesive in an amount of 7% by volume. A circuit board 16 was prepared.
Then, the circuit board 16 was loaded into the container 3.
The IC12 is placed on the IC12, and then, while being crimped using a crimping jig whose at least one side is transparent, UV rays having an energy of 2000 mJ/cm ² are irradiated to cure the coating film. A substrate-attached component B according to the present invention was obtained.

When the electrical operation of Part B thus obtained was examined, it worked perfectly without any short circuits or the like. In addition, when a thermal shock test was conducted at 85 to -40°C, this product showed the same operation as the initial operation even after 1000 cycles.

Example 2 As shown in FIG. 7, a cylindrical resistor 20
is placed in a container 21 made by molding an amorphous polyester film with a thickness of 0.2 mm, with the top back surface protruding toward the storage section, and the anisotropically conductive adhesive film 2
4 and placed on the flexible circuit board 22 partially provided with the reinforcing plate 23, using a crimping jig equipped with an elastic body on the crimping surface side that can follow the cylindrical shape. When thermocompression bonded at ℃ and 30Kg/cm ² , they were completely integrated. In this case, the board is a 38 μm thick polyester film printed with the desired circuit using silver paste, and movable strips are provided around the connection terminals by slits as in Example 1, and anisotropically conductive adhesive Membrane is thermoplastic
Particle size 5 for insulating adhesive based on SBR resin
This is a film made by casting an anisotropic conductive adhesive containing 6.5% by volume of spherical solder alloy of ~15μm.

Next, when the contact resistance of the component C with the board obtained in this way was measured, the initial average resistance was 0.63Ω.
It was confirmed that the contact resistance only slightly increased to 0.71Ω even after being held at 70°C for 1000 hours.

(Comparative Example) A component with a board was made in the same manner as in Example 2 except that the container of Example 2 was not used and the movable strip was not formed on the board, and when the welding resistance was measured, the initial average resistance was 0.65Ω increased to 1.53Ω after 1000 hours at 70°C, and peeling or lifting phenomena were observed.

(Effects of the Invention) The parts of the present invention are integrated with the container and bonded to the substrate, so even if the substrate vibrates due to impact,
The connection between the electrode terminal and the connection terminal does not peel off, and the bond between the container and the board is extremely strong due to the insulating adhesive, and there is no possibility of poor contact or mistakes between the electrode terminal and the connection terminal due to thermal expansion of the board. It has few connections, is highly heat resistant and moisture resistant, and requires less man-hours to attach parts to the board, making it economical and industrially useful.

[Brief explanation of drawings]

FIG. 1 is an exploded perspective view of a component with a board of the present invention;
FIG. 2 is a sectional view showing a state in which components used in the present invention are housed in a container, FIG. 3 is a longitudinal sectional view showing a state in which electronic components are placed in a container different from that in FIG. FIG. 4 is a bottom view of the IC used in Example 1, FIG. 5 is a vertical cross-sectional view showing a component with a board according to the present invention incorporating the electronic component shown in FIG. 4, and FIG. 6 is used in FIG. FIG. 7 is a plan view showing the main parts of the circuit board according to the second embodiment, and a vertical cross-sectional view of a component with a board according to the present invention according to the second embodiment. 1, 12, 20... Parts, 3, 14, 21... Container, 4... Opening, 6, 16, 22... Circuit board,
7, 17... Connection terminal, 2, 13... Electrode terminal, 5,
15...flange, 8,18...slit, 9,1
9, 24... Anisotropic conductive adhesive film, 10... Elastic body, 1
1... Protrusion, A, B, C... Parts with board.

Claims (1)

[Claims] 1. An anisotropically conductive adhesive film having conductivity only in the film thickness direction is used to connect the electrode terminal of an electrical/electronic component inserted through the opening of a flange-equipped container and the connection terminal of a circuit board to be connected to it. An electrical circuit with a board, characterized in that the connecting terminal surrounding portion of the circuit board becomes a movable strip due to a slit surrounding the connecting terminal, and the flange and the circuit board are bonded and held with an insulating adhesive. electronic components.