JP2640009B2 - Interlayer connection method for metal substrates - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an interlayer connection method for a metal substrate that connects a wiring pattern on a metal substrate used for various electronic devices and a metal plate as a base material thereof. Things.

(Prior Art) A conventional interlayer connection method of a metal substrate will be described with reference to FIGS. 3 and 4. FIG. FIG. 3 is an enlarged sectional view of a main part showing a first conventional example, in which a metal substrate is an aluminum plate, an iron plate,
A wiring pattern 3 is formed by laminating an insulating layer 2 made of resin or the like and a copper foil on the surface of a metal plate 1 such as a stainless steel plate or the like, and then etching or the like.

According to the conventional interlayer connection method, a through hole 3a is formed in the wiring pattern 3 by etching or the like, a screw hole 1a is formed in the metal plate 1 through the insulating layer 2 concentrically with the through hole 3a, and a small screw 4 is tightened from the wiring pattern 3 side. The head 4a and the wiring pattern 3 are electrically connected with the solder 5 and mechanically fixed, and furthermore, it is possible to prevent moisture, gas and the like from entering the fitting surface between the small screw 4 and the screw hole 1a. Therefore, the screw tip 4b is sealed with the resin 6.

4 (a) and 4 (b) are enlarged cross-sectional views of main parts showing second and third conventional examples. In the second conventional example shown in FIG. A counterbore 1b is provided on the plate 1, and in the third conventional example shown in FIG.
An opening 2a is formed in the metal plate 1 to provide an exposed portion 1c.
In the prior art example, the spot facing portion 1b and the wiring pattern 3 are electrically connected to each other, and in the third conventional example, the exposed portion 1c and the wiring pattern 3 are electrically connected by wires 7 by a wire bonding method.

The metal substrate has a structure in which the wiring pattern 3 is provided on one side of the insulating layer 2 and the conductive metal plate 1 is provided on the other side. If it can be connected, simply replace the metal plate 1 with a case, shield,
It can be used not only as a heat sink or the like, but also as a circuit configuration conductor common to all circuits such as a power supply circuit and a ground circuit, and can be used as if it were a double-sided through-hole board.

(Problems to be Solved by the Invention) However, in the interlayer connection shown in the first conventional example,
Not only is it not suitable for high-density mounting because it requires a large area for interlayer connection, it is difficult to form the screw hole 1a with the thin metal plate 1, and the electrical connection between the metal plate 1 and the small screw 4 is soldered. Otherwise, the connection tends to be uncertain. In addition, it requires processing of the screw hole 1a of the metal plate 1, mounting of the small screw 4, soldering of the head 4a to the wiring pattern 3, resin sealing of the tip of the small screw, or soldering. However, there is also a problem that connection costs are high.

Further, in the interlayer connection method shown in the second and third conventional examples, the area required for the interlayer connection is smaller than that in the first conventional example. Depending on the location of the wire bond and the material of the metal plate, it is necessary to apply gold plating to the spot facing portion 1b and the exposed portion 1c, which not only increases the cost but also causes a problem that the wire 7 is easily disconnected when an external force is applied. Furthermore, the second
In the prior art, there is a problem that the counterbore processing is required, so that the cost is increased, and in the case of a thin metal plate 1, the counterbore processing is difficult. Further, in the third conventional example, a thin metal plate 1 can be used. However, since the partial removal of the insulating layer 2 requires a complicated etching process, there is a problem that the cost is increased.

The present invention solves the above-mentioned problems, and enables a low-cost interlayer that can be reliably and easily electrically connected to an arbitrary portion on a substrate, regardless of the thickness of a metal plate, within a small substrate area. It provides a connection method.

(Means for Solving the Problems) In order to solve the above problems, the present invention provides a method for mounting a metal substrate on a worktable with a wiring pattern side down, and then forming a conical tip with an apex of an acute angle. A press-fitting tool is to press-fit a portion of the metal substrate to be connected between layers from above, until the tip of the tool penetrates the metal substrate and reaches the processing table.

(Operation) According to the above-described interlayer connection method, first, the tip of the press-fitting tool enters the metal substrate by compressing while excluding the metal plate, the insulating layer and the wiring pattern to the periphery thereof, and then enters the press-fitting tool. When the tip reaches the worktable, the metal substrate is compressed between the upper surface of the worktable and the conical surface, and a highly extensible metal plate extends beyond the insulating layer to the wiring pattern, and the two are brought into direct contact and cold It is pressed and connected between layers.

Embodiment An embodiment according to the present invention will be described with reference to FIGS.

1 (a), 1 (b) and 1 (c) are enlarged cross-sectional views of a principal part showing an interlayer connection method as a comparative example for explaining one embodiment of the present invention in the order of steps. The metal substrate is
The description is omitted because it is not different from the conventional example shown in FIG.

In FIG. 1 (a), first, a steel working table 8 is placed on a table such as a hydraulic press or a crank press, and
A steel or cemented carbide press-fitting tool 9 having an acute conical tip 9a is attached to its plunger, respectively.
Next, the metal substrate is placed on the worktable 8 in such a manner that the metal plate 1 is on the lower side such that the portion to be connected between layers is directly below the press-fitting tool 9.

Next, as shown in FIG. 1B, the plunger is lowered, the conical tip 9a of the press-fitting tool 9 is pressed into the metal substrate, and the tip is slightly bitten into the surface of the worktable 8. At this time, the wiring pattern 3 having excellent extensibility extends beyond the insulating layer 2 and directly contacts the metal plate 1, and the direct contact portion 10 is formed by the conical tip 9 a of the working table 8 and the press-fitting tool 9.
The wiring pattern 3 and the metal plate 1 are interlayer-connected. FIG. 1C shows a state in which the interlayer connection has been completed.

2 (a), 2 (b) and 2 (c) are enlarged cross-sectional views of an essential part showing an embodiment according to the present invention in the order of steps. This embodiment is different from the comparative example shown in FIG. The point is that the metal substrate is placed on the processing table 8 such that the wiring pattern 3 is on the lower side. This is similar to the example shown in FIG.
When the wiring pattern 3 is thin or the insulating layer 2 and the metal plate 1 are thick, the rolled wiring pattern 3 reaches the metal plate 1 Otherwise, there is a possibility that reliable interlayer connection may not be obtained. In the present embodiment, as shown in FIG. 2 (b), the metal plate 1 is rolled, and the direct contact portion 11 between the tip thereof and the wiring pattern 3 is cold-pressed to make interlayer connection.

After the interlayer connection is completed, if the connection portion is coated, filled, or soldered with a resin, the connection reliability can be further improved.

(Effects of the Invention) As described above, according to the present invention, by using a press-fitting tool having a sharp conical tip and a worktable made of steel or the like and a press for mounting the same, the thickness of the metal substrate is reduced. Irrespective of this, an arbitrary portion can be connected at a low cost by one operation.

Furthermore, since the wiring pattern and the metal plate are connected by interlayer pressure welding, highly reliable interlayer connection is achieved.

Even when the wiring pattern is thin, or when the insulating layer and the metal plate are thick, the interlayer connection can be reliably performed.

Further, the area required for interlayer connection may be about the same as that of a general through-hole board, and high-density mounting is possible. Furthermore, the metal plate can be used as a conductor for circuit configuration common to all circuits such as power supply circuits and ground circuits, and even if it is a single-sided metal substrate, it exhibits wiring processing ability comparable to a double-sided through-hole substrate. , High-density mounting becomes possible. In particular, when the metal plate is a ground circuit, the ground impedance can be kept extremely low, and an electric circuit with stable operation can be obtained.

[Brief description of the drawings]

FIG. 1 is an enlarged cross-sectional view of a principal part showing an interlayer connection method as a comparative example for explaining one embodiment of the present invention in the order of steps, and FIG. 3 and 4 are enlarged cross-sectional views of a main part showing a conventional interlayer connection method. 1 Metal plate, 1a Screw hole, 1b Counterbore, 1c
Exposed part, 2 ... insulating layer, 3 ... wiring pattern, 3a ... through hole, 4 ... small screw, 4a ... head, 4b ... screw point, 5 ...
... solder, 6 ... resin, 7 ... wire, 8 ... processing table,
9 ... Press-fitting tool, 9a ... Conical tip, 10,11 ... Direct contact part.

Claims (1)

(57) [Claims] A metal substrate having a wiring pattern formed on an insulating layer provided on a metal plate is placed on a worktable with the wiring pattern facing downward, and a sharp conical tip is formed. A method of connecting the metal substrate between layers, wherein a tip of the press-fitting tool is press-fitted from a surface of the metal plate until the tip of the press-fitting tool penetrates the metal substrate and reaches the processing table.