JPS6243085A - Compression bonded terminal construction - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a pressure contact terminal structure in which, for example, a thermal head circuit configured on an insulating substrate and an external circuit are press-connected.

(Prior Art) FIGS. 3 and 4 are a plan view and a cross-sectional view showing a conventional pressure contact terminal structure. In the figures, (1) is an insulating substrate, (2)
are attached on this insulating substrate (1).
3) is an aluminum conductor attached to cermet (2), (
4) is a copper terminal attached to the aluminum conductor (3), (5) is a gold terminal plated on top of it, and (6) is this gold terminal (
5) A terminal for an external circuit placed on top of the circuit.This terminal is a gold flexible printed circuit. (7) is a pressure welding rubber that is connected by pressing the gold terminal (5) and the flexible printed circuit (6); (8) is a heating resistor;
(9) is an aluminum conductor pattern, (it) is a heating resistor (
8) and the aluminum conductor pattern (9) in its vicinity.
A protective film such as ift, etc., a thermal paper, and a rubber roller (2) for conveying this thermal paper circle.

It is common knowledge that electronic components have become smaller and cheaper in recent years.

It is clear that the level of thin film technology, thick film technology, etc. will continue to improve, and the conventional pressure contact terminal structure of the thermal head is constructed as described above by forming a heating resistor.

This thermal head is used for facsimiles, printers, etc.
This is the main component used, and a pulse voltage is applied to the dots formed by arranging a plurality of heating resistors (8) on an insulating substrate (1), and the heat generated by the dots prints letters and symbols on the thermal paper. Continuous printing is carried out by conveying the heat-sensitive paper by the conveying rubber roller 4.

Now, thin film technology is used in the manufacturing process of this thermal head, and cermet (2) and aluminum conductor (3) are successively deposited on an insulating substrate (1) using a sputtering device. Conductor pattern (9) of aluminum conductor (3) and heating resistor (8) are patterned using a plate-making process.
) will be formed. Here, the circuit formed on the insulating substrate (1) operates with input signals from the external circuit, etc.
Must be connected to an external circuit.

Press-fit connections are known as methods of this type. This pressure welding connection connects the terminals of the connection part with pressing force, and in pressure welding of dissimilar metals such as aluminum and gold terminals, the connection part is one part that acts as a battery, so reliability is poor, and Because aluminum is prone to corrosion, pressure welding with all terminals connected was highly reliable and commonly used.

By the way, in order to reduce the price of electronic components using thin film technology such as thermal heads, it is necessary to minimize the use of expensive precious metals, and it is best to use gold only for the connection terminals with external circuits. Become. Therefore, the aluminum conductor (
3) Proposals have been made to make the top part gold. Print sintered gold paste on the aluminum conductor (3) of the connection terminal part,
Firing is not possible due to the restriction that the firing temperature is higher than the melting point of aluminum, so a method of gold plating on the aluminum conductor (3) of the connection terminal portion is used. Gold plating on the aluminum conductor (3) is difficult because aluminum is easily oxidized and an oxide film is formed on the surface, so copper (4) is interposed on the aluminum using a sputtering process, and gold plating is performed on top of the copper (4).

The intervening copper (4) is the heating resistor (8) on the insulating substrate (1)
And the aluminum conductor pattern (9) near it is covered with a protective film αQ of 5iOa etc. by sputtering, and then copper (
After forming a film of 4) on the entire surface of the substrate, a connection terminal pattern of copper (4) with an external circuit is formed on the aluminum conductor by patterning using photolithography. Next, gold plating is copper (4
), and the gold terminal portion of the flexible printed circuit (6), which is an external circuit, is placed on the gold terminal (5) and connected by pressing in the direction of the arrow in the figure with the press-contact rubber (7). Since the pattern of the above-mentioned flexible circuit (-) is generally copper, it is convenient to plate only the terminal portion of the circuit (6) with gold.

[Problems to be Solved by the Invention] Since the conventional press-contact terminal structure is configured as described above, it is necessary to interpose a metal such as copper that is easily gold-plated in order to make the terminal portion on the insulating substrate gold. This requires a large number of steps, and the adhesion between the terminal conductor and the intervening metal, as well as between this metal and the plated gold, is weak, reducing reliability, resulting in stiffness, high cost, etc. There was a problem.

This invention is the second invention to solve the above-mentioned problems, and it is possible to eliminate the gold on the insulating substrate, reduce the cost by 1-1, and obtain three highly reliable pressure-welding ends. With the goal.

[Means for solving problems]

In this press-contact terminal structure (this invention), a connection terminal of a circuit on an insulating substrate is covered with a graphite-based conductive paste whose binder is a resin that hardens with heat or the like.

Function] The insulation displacement terminal structure of the present invention is made by printing a conductive paste, which is a mixture of graphite and carbon black powder in a resin solution such as phenol, epoxy, polyimide, etc. that hardens with heat, on the aluminum conductor that will become the terminal. By curing under the curing conditions of the resin, the terminal becomes an electrically stable carbon terminal, and it also adheres strongly to the AJI/E conductor, using resin 8 whose curing conditions are lower than the melting point of the aluminum conductor. It is characterized by its adhesion and conductivity, which is determined by the amount of graphite, carbon black powder, etc. mixed.

Embodiment of the Invention] Hereinafter, an embodiment of the invention will be described with reference to the drawing numbers. 1 and 2 show a front view and a sectional view thereof. (1)
(2) is the insulating substrate (1) attached to the insulating substrate (R).
The f-cermet 5 (3) is the aluminum conductor attached to the cermet (2), and the grooves are the aluminum conductor (3) on the pressure contact terminal.
J: A graphite-based conductive paste (hereinafter referred to as carbon paste) using printed and cured polyimide as a binder, (6) is an external paste placed on the carbon paste paste on the insulating substrate (1). This is a flexible printed circuit with gold-plated terminals. (
7) is a pressure contact rubber that presses and connects the carbon pace drum and the flexible printed circuit (6); (8)
is the heating resistor, (9) is the aluminum conductor pattern, and αQ is the heating resistor (8) and the aluminum conductor pattern (9) near it.
A protective film such as 8102 that covers (6) is thermal paper, (6)
is the rubber roller that conveys the thermal paper αυ.

The pressure contact terminal structure configured as described above becomes the connection terminal position with the external electric circuit on the insulating substrate (1) after the protective film (IQ film is formed). After printing and drying the paste μs, cure it with one trowel under polyimide curing conditions (about 850°C).

This curing condition is based on the cermet (2) on the insulating substrate (1).
), the aluminum conductor (3) 1, the heating resistor (8), the aluminum conductor pattern (9), and the protective film α1 are not affected. Also.

As is well known, polyimide has few ionic components such as sodium and does not have any negative effects such as corrosion on metals such as aluminum, and sufficient adhesion can be obtained by curing, and the aluminum conductor (3) is made of polyimide and fine graphite.・Covered with carbon black powder. As is well known, carbon terminals are stable without problems such as oxidation and corrosion, and due to the conductivity of the carbon powder in the press-contact terminal part, all terminals of the flexible printed circuit (6) are press-contacted with the pressing force in the direction of the arrow in the figure. Can be connected. In addition, the pressure contact resistance due to pressure is less than the specified value 1
This is determined by the amount of carbon powder mixed into the polyimide.

In the above embodiments, polyimide is used as the binder material, but it may also be phenol resin, epoxy resin, synthetic rubber, glass frit, ultraviolet curing resin, or silicone resin.

Further, in the above embodiment, the case where the circuit with the insulating substrate is a thermal head is shown, but if the circuit on the insulating substrate is an image sensor consisting of a circuit of a hydrogenated tetrahydral type amorphous semiconductor, it is also possible to use other circuits. It may be a circuit using thick film technology, and the same effect as the above embodiment can be achieved.

Furthermore, gold powder may be mixed into the carbon paste to improve conductivity.

(Effects of the Invention) As explained above, this invention [According to this invention, the aluminum conductor of the press-contact terminal part is covered with carbon paste, so it does not require money, is low cost, and has high reliability. This has the effect of providing a pressure contact terminal structure.

[Brief explanation of the drawing]

1 is a plan view of a pressure contact terminal structure showing an embodiment of the present invention, FIG. 2 is a sectional view taken along the line 1-1 in FIG. 1, FIG. 3 is a plan view showing a conventional pressure contact structure, and FIG. The figure is IY-f in Figure 3.
It is an f-line sectional view. In the figure, (1) is an insulating substrate, <
2> is cermet, (3) is aluminum conductor, (6) is flexible printed circuit, (8) is heating resistor, (
9) is an aluminum conductor pattern, and a3 is a carbon paste. Note that the same reference numerals in each figure indicate the same or corresponding parts. Figure 11. 3. Aluminum bed support C hinoki rt stripe) 6: Flare A spool (2) part size - A = - throat (2) part trouble g -,) t3: n - paste Fig. 2 Fig. 3 Figure 4

Claims (8)

[Claims] (1) A pressure contact terminal structure for press-connecting a circuit on an insulating substrate and an external circuit, characterized in that the connection terminal of the circuit on the insulating substrate is covered with a graphite-based conductive paste. (2) Claim 1, characterized in that the binder material of the graphite-based conductive paste is any one of phenol resin, epoxy resin, synthetic rubber, and glass-based frit.
Pressure contact terminal structure as described in section. (3) The pressure contact terminal structure according to claim 1, wherein the binder material of the graphite-based conductive paste contains polyimide. (4) The pressure contact terminal structure according to claim 1, wherein the binder material of the graphite-based conductive paste contains an ultraviolet curing resin. (5) The pressure contact terminal structure according to claim 1, wherein the binder material of the graphite-based conductive paste contains a silicone resin. (6) Any one of claims 1, 2, 3, 4, or 5, characterized in that the circuit on the insulating substrate is a thermal head in which a heating resistor is formed. Pressure contact terminal structure described in the above. (7) Claims 1, 2, 3, 4, or 4, wherein the circuit on the insulating substrate is a circuit formed of a hydrogenated tetrahydral amorphous semiconductor. The pressure contact terminal structure according to any one of Item 5. (8) Claims 1, 2, and 3, characterized in that the graphite-based conductive paste contains gold powder;
The pressure contact terminal structure according to any one of Item 4, Item 5, Item 6, or Item 7.