JPH0335784B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to a method of connecting leads on a substrate to a flexible wire cable.

For example, as shown in FIG. 1, in order to lead out a plurality of leads 2 patterned on the surface of a substrate 1 made of ceramic such as alumina,
A flexible wire cable (hereinafter simply referred to as FWC) 3 may be used. The FWC 3 is composed of a synthetic resin sheet 4 and leads 5 patterned on the surface thereof. When connecting the leads 2 and 5, solder is applied to the surfaces of the leads 2 and 5, the leads are overlapped so that they are in contact with each other, and the solder is applied by applying heat and pressure. I have to.

However, conventionally, as shown in FIG. 2, the pressurizing tool 6 itself generates heat, pressurizes the overlapped portion with the pressurizing tool 6, and heats the overlapped portion with the heat from the pressurizing tool 6. was. 7 is a pedestal. According to this method, although it is possible to perform the required soldering, the following problems occur. i.e.
As described above, the FWC 3 is constructed by patterning the leads 5 on the surface of the synthetic resin sheet 4. Now, as shown in Figure 2, FWC3 for board 1
When stacking the leads 2 and 5, the leads 2 and 5 are stacked facing each other, so the upper surface becomes the back side of the sheet 4. When heated by the pressurizing tool 6, the heat traverses the sheet 4 in its thickness direction and reaches the leads 5. Since the sheet 4 is extremely thin, it has the disadvantage that it is susceptible to thermal damage, such as melting, when heat is conducted across it in this manner.

The purpose of this invention is to prevent heat damage to a synthetic resin sheet having one lead when soldering the leads together.

In this invention, both leads are overlapped.
The feature is that only pressure is applied from the FWC side, and heating is performed from the substrate side.

An embodiment of this invention will be explained with reference to FIG.
The purpose of soldering is the same as that of the conventional method, in which the board 1 and the FWC 3 are stacked so that the leads 2 and 5 face each other, and the stacked portion is heated and pressurized to melt the solder on the surface of the leads. However, in this invention, a pressurizing tool 11 is used to pressurize the overlapping portion, but this pressurizing tool does not play any role in heating as shown in FIG. For heating, a heater 12 is prepared and the overlapping portion is placed on the heater 12. And this heater 12
The overlapped portion is heated by That is, heat from the heater 12 is conducted to the leads 2 and 5 via the substrate 1. In this case, substrate 1
Although it is thicker than FWC3, since it is made of ceramic, it has good thermal conductivity and is resistant to thermal stress, so it is possible to heat the substrate 1 from the back side.
This heat melts the solder on the surface of the leads, and at this time, the leads 2 and 5 are pressed together by the pressure tool 11, so that the leads 2 and 5 are soldered together. At this time, there is no need for the heat from the heater to be conducted across the sheet 4 to the leads 5, so that thermal damage to the sheet 4 can be reliably prevented.

On the other hand, when heating and pressure bonding is performed from the FWC 3 side as in the conventional case, since the sheet 4 of the FWC 3 is made of synthetic resin, it generally has poor thermal conductivity and poor heat dissipation effect. Therefore, once the heat is conducted from the sheet 4 of the FWC 3 to the leads 5 and the solder is melted and crimped, even if the heat supply is stopped, it takes a long time for the solder to solidify. Therefore like this
If heating and crimping is performed from the FWC3 side, it is not suitable for mass production.

However, as in this invention, heating is performed from the side of the substrate 1 made of ceramic, which has better heat dissipation than synthetic resin, and before the heat is transferred to FWC 3, which has poor heat dissipation.
When both leads 2 and 5 are thermocompression bonded via solder and then the supply of heat is stopped, heat can be radiated in a short time using the substrate 1 as a heat radiation fin, and the solder can be solidified.

Moreover, in order to further shorten this time, the heating area A of the heater 12 is made equal to the overlapping area of the leads 2 and 5. This ensures that the area is the minimum necessary to raise the temperature to a point where the solder can be melted, and that heat is not transmitted to areas other than the required areas.

Moreover, in order to increase the area in contact with the outside air as much as possible so that the substrate 1 can efficiently act as a heat dissipation fin, the heater 12 is installed on the surface of the pedestal 7, so that a heat dissipation space 1 is created around the heater 12.
form 3.

As described above, according to the present invention, when soldering the FWC leads to the leads of the board,
Since heat is not conducted across the synthetic resin sheet that makes up the FWC, heat damage to the synthetic resin sheet can be reliably prevented, and FWC with low heat resistance can be used as the synthetic resin sheet. Furthermore, since the heat dissipation effect can be improved, mass production becomes possible.

[Brief explanation of the drawing]

Figure 1 is a perspective view showing how the leads are connected;
The figure is a front view showing the steps of implementing the conventional method, and FIG. 3 is a front view showing the steps of implementing the method of the present invention. 1... Board, 2... Lead, 3... FWC, 4
... Sheet, 5 ... Lead, 11 ... Pressure tool, 1
2...Heater.

Claims (1)

[Claims] 1. Leads on the surface of a substrate made of ceramic;
A sheet made of synthetic resin and the lead of a flexible wire cable consisting of a lead patterned on the surface of the sheet are overlapped with each other with solder interposed therebetween, and both of the overlaid leads are bonded by thermocompression on a pedestal. In the lead connection method, a heater is installed between the pedestal and the board, the heating area being equivalent to the overlapping area of both the leads, and a heat dissipation space is formed around the heater, and A pressure tool that presses the flexible wire cable is arranged above the heater, and while the heater heats from the board side and melts the solder, the pressure tool presses the board and the flexible wire cable. A lead connection method characterized in that the lead is crimped to the cable.