JPS5963790A - small electronic circuit parts - 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 small electronic circuit component J' (small, high density, and highly reliable).

Conventional configurations and their problems In recent years, various electronic devices, including video tape recorders (VTRs), have made remarkable progress in becoming smaller, lighter, and thinner. There is also an increasing demand for smaller and more dense electric circuits.

Conventionally, various methods have been used to make electrical circuits smaller and more dense. There is a method of configuring a circuit by mounting block modules on a mother printed circuit board. This circuit block module is a small electronic circuit component in which several circuit elements are densely mounted and interconnected on a small circuit board, and is commonly known as a hybrid IC (hybrid integrated circuit component).
It is also called as "synthesis", and various types are currently in use.

As shown in Fig. 1, a typical small electronic circuit component is a so-called so-called one in which a metal glaze silver-palladium conductor circuit 2 and a ruthenium oxide resistor 3 are formed on a ceramic substrate 1 made of alumina or the like. Individual circuit elements 4 such as chip capacitors, transistors, coils, and semiconductor ICs are mounted and soldered on a thick film substrate, and lead wires 5 are further attached as external connection terminals.

However, such small electronic circuit components have the following drawbacks.

(1) The manufacturing process is complicated and the manufacturing equipment is large-scale.

(2) As the scale of the block circuit increases, the overall size of the block becomes larger in comparison, which reduces the mechanical strength of the alumina board, and increases the area it occupies when attached to the mother printed board. This becomes a hindrance to increasing density.

(3) Since the lead wire is attached later as an external connection terminal, its installation is complicated, and the solder connection between the lead wire and the circuit block lacks reliability.

(4) Extra space is required to attach the lead wires within the circuit block, making it difficult to achieve high density within the circuit block, and when attached to the mother printed circuit board, the part where the lead wires are attached may Since it protrudes from the board, it is disadvantageous in electrical circuits with strict height restrictions, and substantially densification of the circuit board is inhibited.

Purpose of the Invention The present invention completely eliminates the above-mentioned drawbacks of the conventional example.By combining a metal plate and a flexible wiring board, lead terminals and block circuits are integrated, and the block circuit has a high density. The present invention provides a small electronic circuit component having a structure that allows high circuit density to be achieved when attached to a mother printed circuit board as the technology advances.

Structure of the Invention The electronic circuit component of the present invention is provided with lead terminals serving as external connection terminals at both ends of a pair of opposing ends, and one side of a metal plate is hollowed out in a desired wiring circuit shape continuously from the lead terminals. A flexible wiring board having a circuit conductor formed on at least one main surface of a flexible insulating substrate is adhered to the surface of the flexible wiring board so that the lead terminals of the metal plate are exposed, and the circuit conductor of the flexible wiring board is bonded to the surface of the flexible wiring board. and the wiring circuit conductor of the metal plate are electrically connected to each other, and a circuit element is mounted on the flexible wiring board and electrically connected to the circuit conductor of the flexible wiring board.

Description of examples Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 is a partial perspective view of an embodiment of a small electronic circuit component according to the present invention, and FIG. 3 is a sectional view of the same.
The structure of this small electronic circuit component is such that the lead terminal portion is exposed on one surface of a metal plate 6 that integrates a lead terminal and a wiring circuit conductor and is drawn out to the outside using a flexible wiring board. 7 is glued with adhesive 8,
Circuit elements 9 necessary for constructing a block circuit are mounted on the upper surface of the flexible wiring board 7 and are electrically connected to the flexible wiring board by solder 1o, and are drilled into the circuit conductor portion 7a of the flexible wiring board. The flexible wiring board 7 and the metal plate 6 are electrically connected through the through holes with solder 1o.

The more specific structure of this small-sized electronic circuit component according to the present invention will be explained in detail according to its manufacturing method.A metal plate such as an iron-nickel alloy, copper, nickel, iron plate, or phosphor bronze plate is etched or punched. Then, as shown in FIG. 4, lead terminals 6a, 6a' are attached to opposite ends.
A metal plate 6 is created in which conductor layers eb and 6b' are left in a desired wiring circuit shape continuously from the lead terminals 6a and 6a'. Next, the lead terminal portion 6a is attached to the surface of this metal plate 6.
, 6a' are exposed and drawn out, and a polyimide film 7 is placed on one surface of the other metal plate.
A flexible 5'a wire board 7 with a desired wiring circuit conductor 7ai made of copper foil formed on one surface and a through hole 6 formed thereon is used as a base, and an epoxy resin or an adhesive 8 is applied to the back surface of the flexible wire board 7. Adhesion is achieved by applying a thermosetting adhesive such as polyurethane resin, an adhesive tape, or a thermoplastic adhesive such as Teflon, which softens at high temperatures. Further, on the wiring circuit conductor surface of the flexible wiring board 7, there are resistive capacitors and transistors as planar connection type small circuit elements 9 necessary for constructing a block circuit.

A semiconductor IC or the like in an ultra-small package is mounted, and these circuit elements are electrically connected to the wiring circuit conductor 7a of the flexible wiring board 7 with solder 10 by a solder dipping method or a flow soldering method.

Then, at the same time as connecting the circuit element 9 to the flexible wiring board 7, the wiring circuit conductor portion 7a of the flexible wiring board 7 is connected.
The flexible wiring board 7 and the metal wiring circuit conductor eb on the lower surface are passed through the through hole 7b made in the .

Electrically connect e and b' with solder 1o. In this case, the wiring circuit conductor 7a of the flexible wiring board 7 and the metal plate 6
Electrical connections between the wiring circuit conductors eb and eb' may be made by filling conductive resin such as silver paste through the through holes 7b.

Furthermore, in order to make the connection between the flexible wiring board 7 and the wiring circuit conductor of the metal plate 6 more reliable, it is possible to use a flexible wiring board with so-called through-hole plating, which forms a conductive layer on the through-hole walls of the flexible wiring board. It has also been proven to be good.

FIG. 5 shows the state in which the small electronic circuit component according to the present invention is mounted on a mother printed circuit board, and the small electronic circuit component according to the present invention has the structure shown in FIGS. 2 and 3. Bend it in two from the center, insert the lead terminal into the insertion hole of the mother printed circuit board, and solder it. By adopting this mounting structure, small electronic circuit components are mounted on opposite sides, which reduces the area occupied on the mother printed circuit board, allowing for higher density and easier manufacturing. The method can be carried out using only a single-sided processing process, and it is also possible to produce metal plates and flexible wiring boards by winding them into long rolls so that multiple pieces can be produced, thereby streamlining production and mass production. becomes possible.

FIG. 6 explains a second embodiment of the present invention, in which a metal plate 6c is placed along both the left and right ends of the flexible wiring board 7, continuing from the lead terminals at both the left and right ends of the lead terminals 6a and 6a'.
By having such a structure, the shape of the small electronic circuit component becomes stable when it is folded in two, and it becomes easy to insert it into the mother printed circuit board. Further, by providing a notch in the center of the metal frame 6c at both the left and right ends of the flexible wiring board 7, it becomes easy to bend the small electronic circuit component in two, and it becomes easy to insert the small electronic circuit component into the mother printed circuit board. In this case,
The opposing lead terminals on both the left and right ends are disposable terminals that have no relation to the circuit function.

FIG. 7 illustrates a third embodiment of the present invention, in which a wide-area metal plate circuit 6d is constructed in continuation with a lead terminal 6a or 6a', and flexible wiring is formed on the upper surface of the metal plate circuit 6d. A hole is cut out in the plate, a long-hole thermoconductive adhesive 11 is applied to a large area of the metal plate, and a circuit element that generates heat that consumes a large amount of power is placed on top of the metal plate. Power transistors and I(
4, and their terminals are soldered to the circuit conductors of the flexible wiring board 7. With such a configuration, a block circuit with excellent heat dissipation characteristics can be obtained. According to this embodiment, a high-power circuit block module having about one layer can be realized.

FIG. 8 explains a third embodiment of the present invention, in which an insulating layer is placed on the surface of the substrate formed by the flexible wiring board 7 and the metal plate 6, on which the circuit elements are not mounted. As the hard reinforcing plate 14, a synthetic resin substrate such as a glass epoxy laminate or paper phenol is bonded so that the central part of the flexible wiring board can be bent freely. The distance between opposing lead terminals obtained by bending the electronic circuit component in two is maintained constant, and the mechanical strength thereof is improved and attachment to the mother printed circuit board is facilitated. It's 1.
This hard plate may be adhered to the entire surface other than the lead terminal portion, and the lead wires may be arranged on both sides to form a dual in-line type.

FIG. 9 explains a fourth embodiment of the present invention, in which a large number of resistors 15a and electrode terminals 15bi are mounted on an alumina substrate 15' on the lower surface of a flexible wiring board 7.
A thick film resistor module 15 formed by printing is connected to a wiring circuit conductor 7a of an adhesive flexible wiring board 7 and an electrode terminal 15b of the thick film module 15 through a through hole 7b using a solder 10. In a small electronic circuit component having such a configuration, circuit elements are formed on both sides of the flexible wiring board, so when folded, the components are arranged in four layers, which increases the density of the circuit blocks. The figure explains a fifth embodiment of the present invention, in which a semiconductor chip 16 is directly mounted on a metal wiring circuit conductor surface 6b, wire-bonded with a gold wire 17, and the surrounding area is It has a structure in which the parts are sealed with resin 18. By adopting such a configuration, the block circuit can be made smaller and more densely packed. In this case, the semiconductor chip 16
The part of the metal wiring board eb' on which the semiconductor chip 16 is mounted is plated with gold, and a hole is cut out in the flexible wiring board of that part, and the cutout hole is used to seal the semiconductor chip 16 with resin. This is to prevent the flow of water.

As described in detail of the invention, the small electronic circuit component according to the present invention comprises:
It has unparalleled manufacturing features such as a simple manufacturing process and high mass productivity.

In addition, in terms of structure, since it can be bent in two and attached to the mother printed circuit board, the area it occupies can be reduced, and higher density can be achieved on the mother printed circuit board. Since the blocks are integrated, many effects not found in conventional examples can be obtained, such as higher density and improved reliability.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a conventional small electronic circuit component, FIG. 2 is a partially cutaway perspective view of an embodiment of the small electronic circuit component according to the present invention, and FIG. 3 is an embodiment of the small electronic circuit component according to the present invention. FIG. 4 is a plan view of a metal plate for explaining the structure of the small electronic circuit component of the present invention, and FIG. 5 is a cross-sectional view of an example of the small electronic circuit component of the present invention mounted on a mother printed circuit board. 6 is a partially cutaway perspective view of another embodiment of the small electronic circuit component of the present invention, and FIGS. 7 to 1o are sectional views of still other embodiments of the present invention. 6...Metal plate, 6a, 6a'...External lead terminal, 6b...Wiring circuit conductor by metal plate, 6C...
... Frame made of metal plate, 6d... Wide area metal plate, 7... Flexible wiring board, 7'...
・Flexible insulating substrate, 7a...Wiring circuit conductor,
7b...Through hole, 8, 12...Adhesive,
9...Circuit element, 10...Solder, 1
1... Adhesive (thermal conductivity), 13...
High power circuit element, 14... Hard reinforcing plate, 16.
...Thick film module, 15'...Alumina substrate, 16a...Resistor, 15b...
Electrode terminal, 16... Semiconductor chip, 17...
... wire, 18 ... sealing resin. Name of agent: Patent attorney Toshio Nakao and 1 other person83
Figure 1 □--V-□ Figure 2 Figure 6 N \Q \ )

Claims (6)

[Claims] (1) Lead terminals serving as external connection terminals are provided at both ends of a pair of opposing ends, and a flexible A flexible wiring board in which a circuit conductor is formed on at least one main surface of an insulating substrate having a conductive material is mounted on the flexible wiring board with the lead terminals of the metal plate exposed. A small electronic circuit component that is electrically connected to a circuit conductor. (2) Along both left and right ends of the flexible wiring board,
A small electronic circuit component according to claim O), in which continuous metal plates are bonded to lead terminals at both left and right ends to form a frame. (3) A small electronic circuit component according to claim (2), wherein a spark is provided in the center of the framed metal plate. (4) Provide a wide metal plate continuous to the lead terminal,
A flexible wiring board that is bonded to the top surface of this metal plate is hollowed out, and circuit elements with large power consumption are mounted on the flexible wiring board by using an adhesive with excellent thermal conductivity on the exposed metal plate. , a small electronic circuit component according to claim (1), which is electrically connected to each other. (5) A small electronic circuit component according to claim (1), in which an insulating hard reinforcing plate is adhered to a part of the surface of a metal plate in the form of a wiring circuit. (6) Claim No. 1, wherein a thick film circuit board on which a plurality of resistors are formed is adhered to the back surface of a flexible wiring board and electrically connected to the circuit conductor of the flexible wiring board.
Small electronic circuit components listed in Section 1.