JPS6041429B2 - Conductive bonding method between metal and metal foil - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of joining a metal plate and a metal foil, and in particular, the present invention relates to a method of joining a metal plate and a metal foil, and in particular, a metal foil temporarily pasted on a metal base material by the adhesive force of a non-conductive resin layer. This is intended to conductively bond a metal plate, and in particular, during this bonding, the resin layer is removed, the metal foil and the metal plate are brought into direct contact, and ultrasonic vibration is applied using a horn to generate frictional heat, thereby creating a strong bond. The present invention provides a bonding method that provides electrical conductivity.

Conventionally, as an example of a conductive bonding method between a metal plate and metal foil, there is a case where lead wires are bonded to a circuit pattern on a printed circuit board. A circuit is created by etching the foil, and then a resin material for an insulating coating is applied to the parts of the electrical element except for the solder joints using a screen printing method to form a coating.

Therefore, when electrically wiring lead wires, etc. to the circuit pattern of the board, it is necessary to conductively connect them by soldering, caulking, etc. after peeling off the film, and the process of peeling off the film and the process of joining must be performed. There is a drawback that two are required, which increases the cost of assembling the electrical wiring board. Furthermore, a thin printed circuit board has the disadvantage that the printed circuit board becomes thicker due to the lead wires. Therefore, a method of attaching metal foil coated with a non-conductive resin layer instead of the lead wire (or jumper wire) may be considered. However, in this method, since the non-conductive resin layer is also used at the points to be electrically conductive, conductivity cannot be obtained by the normal method, and after the step of peeling off the resin layer at the points to be electrically conductive, soldering or It was necessary to caulk, etc. The present invention eliminates these conventional drawbacks and enables conductive bonding of a metal plate and metal foil through a simple process. An embodiment of the method of the present invention will be described below with reference to the drawings.

FIG. 1 shows the configuration of an ultrasonic welding machine for carrying out the method of the present invention.

In the figure, reference numeral 1 denotes a tip with a special shape, which is connected to a tool horn 2 by a screw. 3 is a vibrator, and this vibrator 3 converts the high frequency electric energy generated by the oscillator 4 into ultrasonic mechanical energy via a cord 5.

6 is a compression spring, which is attached to a shaft 7' provided on the support bracket 7.
Chip 1 is placed on various products placed on pedestal 8 with
It played the role of pressurizing through.

FIGS. 2A and 2B show a conductive bonding method according to the present invention.

In FIG. 2A, the tool horn tip 1 includes a plurality of protrusions la having a predetermined interval, and a recess lb having a predetermined volume between the protrusions la, and the tips of the protrusions la serve as a pressing surface. . The chip 1 is pressurized by the pressure spring 6, and the resin layered copper foil 9 is pressed and bonded onto the circuit pattern 10a made of copper foil or the like on the printed circuit board 10. In this state, the transducer 3 applies horizontal ultrasonic waves to the chip. Gives vibration. As a result, as shown in FIG. 2B, pressing force and lateral vibration are applied to the tip of the protrusion la of the tip, and the resin layer 9b located directly under the protrusion la is removed. At this time, the circuit pattern 11a and the copper foil are bonded via the resin layer, and no slipping occurs due to the ultrasonic transverse vibration, and the bonding is achieved in a short time and reliably. has almost no effect, and the resin layer 9b melted and removed from the adjacent convex portion la flows into the space directly below the concave portion lb.

Therefore, a place for the removed resin layer to escape is secured, and unreasonable pressure is not generated, so that the copper foil 9a and the circuit pattern 10
By eliminating the force that tends to separate a, the bonding can be ensured. From the above, the convex portion la of chip 1
In this case, the copper foil material 9a and the circuit pattern 10a on the printed circuit board 10 are brought into direct contact and conductively bonded by frictional heat generated by ultrasonic vibration. So-called ultrasonic welding is performed. As a result, copper foil with resin layer 9 and pudding 1. It exhibits strong bonding with the circuit pattern 10a made of copper foil on the substrate 10, and provides sufficient electrical continuity. In this embodiment, the steel foil forming the circuit pattern 10a is a metal plate. The method of conductively bonding a resin-layered steel foil to a circuit pattern on a printed circuit board has been described above as an example, but instead of the resin-layered steel foil, a resin-layered metal foil such as resin-layered aluminum foil may be used. It was clear that instead of printed circuit boards, other materials that can be ultrasonically bonded could be bonded by the method of the invention.

As a result of the experiment, the size and optimal shape of the unevenness on the chip 1 are related to the material, quality and thickness of the materials to be bonded, the type and thickness of the resin layer, etc. , In consideration of these conditions, the configuration shown in FIGS. 3 and 4, A to G, etc. can be adopted.

The present invention uses frictional heat and pressure generated by ultrasonic transverse vibration to remove the resin layer and conductively bond the metal plate and metal foil. thermal deterioration and removal due to lateral vibration occur,
The non-conductive resin material for forming the resin layer may be polyester, vinyl chloride, acrylic, polyamide, silicone, etc., thermoplastic type or thermosetting type, and may be an adhesive, hard film, or adhesive layer. Soft films are also applicable.

Further, instead of metal foil, a thin metal plate may be used, and in addition to a combination of metal foil and resin, the present invention can be applied to a case where a resin layer is formed on a metal plate.

The thickness of the metal foil that can be used in the present invention is limited to a thickness that allows the metal foil to be deformed by a chip having an uneven pressure surface.

Generally, the maximum thickness is 3 feet/skin. As is clear from the description of the above embodiments, the method for electrically conductive bonding of a metal plate and metal foil of the present invention involves bonding the metal foil onto the metal plate with a non-conductive resin layer interposed between the metal plate and the metal foil. In a bonding method of conducting conductive bonding with a metal foil, a chip having a pressure surface with predetermined irregularities is pressed against the metal foil and while applying pressure, ultrasonic vibration is applied to the chip, and the vibration energy causes the metal plate to and the metal foil, the non-conductive resin layer is removed from the surface to be welded, and the metal plate and the metal foil are conductively joined. When electrically bonding the metal foil that is insulated and temporarily fixed by the resin layer, the resin layer is removed, and the metal foil can be firmly and electrically bonded to the metal plate.

Regarding the method of conductively connecting a metal wire having a resin coating to a metal plate, there is a similar method of ultrasonic bonding, for example in Japanese Patent Laid-Open No. 52-111861, but in the case of the present invention, As mentioned above, since the joining of metal plates is not a point joining, even if the technology disclosed in the above publication is simply applied, there will be problems with vibration transmission, and the joint will break due to the bulge of the resin removed by chip pressurization. Other issues remain.

The present invention solves these problems and realizes an effective joining method, and its industrial value is extremely large.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of an ultrasonic welding machine for carrying out the method of the present invention, and FIGS. 2A and B are conceptual diagrams showing the method of the present invention. FIG. 2A is before welding; B is a cross-sectional view showing the state after bonding, FIG. 3 is a plan view showing the bonded state of the steel foil with resin layer, and FIG.
Figures A to G are plan views showing various shapes of chip pressurization after conductive bonding between metal foil and metal. 1... Chip, 2... Tool horn, 3...
... Vibrator, 4 ... Oscillator, 9 ... Copper foil with resin layer, 9a ... Copper foil (metal foil), 9b ...
-Resin layer, 10a...Circuit pattern (metal base material). Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] 1 A metal foil is temporarily bonded onto a metal plate via a conductive resin layer, and a plurality of protrusions having a predetermined interval and a recess having a predetermined volume between the protrusions are formed on the metal foil. Ultrasonic vibration is applied to the chip while pressing the pressure surface formed at the tip of the part, and the non-conductive resin layer interposed between the metal plate and the metal foil is caused by the vibration energy. A method for conductively bonding a metal plate and a metal foil, in which the metal base material and the metal foil are electrically bonded by melting and removing the metal from the surface to be welded and moving the metal to the recess of the chip.