JPS60211891A - Method of assembling both-side printed circuit board - 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 [Technical Field of the Invention] The present invention relates to a method for assembling a double-sided printed wiring board used in electronic equipment.

[Prior Art] FIG. 1 is a diagram sequentially showing a conventional double-sided printed wiring board assembly method.

Conventionally, when mounting surface-mounted electronic components such as chip components on a double-sided printed wiring board, the electronic components are first mounted on one side, and then
Electronic components were then mounted on the other side. This will be explained more specifically. First, as shown in FIG.
An adhesive conductive bonding agent 2 such as solder paste is applied to the surface (hereinafter referred to as side A) using a printing machine or the like. Next, as shown in FIG. 1(b), electronic components such as the chip component 3a and the flat package IC 48 are placed on side A using the adhesive force of the conductive bonding agent 2, and then heated in a reflow oven or the like. Then, the conductive bonding agent 2 is melted and bonded. Next, as shown in FIG. 1(C), the double-sided printed wiring board 1 is turned over, and the other side of the double-sided printed wiring board 1, that is, the side indicated by arrow B in the figure (hereinafter referred to as the 8th side) is Apply adhesive conductive adhesive 2. After that, as shown in FIG. 1(d), the chip component 3
Electronic components such as B and flat package IC 4b are heated and fused to the B side by a method similar to that described using FIG. 1(b).

Such conventional double-sided printed wiring board assembly methods have the following drawbacks. That is, in this method, first, the electronic components are mounted on the A side of the double-sided printed circuit board 1.
Since electronic components are mounted on the surface, when electronic components are mounted on the B surface, the electronic components already mounted on the A surface are also heated at the same time. That is, the electronic components mounted on the A side are subjected to thermal stress twice. Therefore, electronic components that lack heat resistance have drawbacks such as high manufacturing costs due to restrictions on manufacturing conditions and product applications to ensure quality reliability, or restrictions on printed wiring board materials. It was exhibiting.

[Summary of the invention] This invention was made to eliminate the above-mentioned drawbacks, and its main purpose is to improve quality reliability by reducing thermal stress on printed wiring boards and electronic components. It is an object of the present invention to provide a method for assembling a double-sided printed wiring board, which can reduce manufacturing costs.

According to the method for assembling a double-sided printed wiring board according to the present invention,
Electronic components are temporarily mounted on both sides of a double-sided printed wiring board using an adhesive conductive adhesive in advance, and then a heat treatment is performed to simultaneously cure or melt-bond the adhesive conductive adhesives on both sides.

An embodiment of the present invention will be described below with reference to FIG.

[Embodiments of the Invention] FIGS. 2A and 2B are diagrams sequentially illustrating a method for assembling a double-sided printed wiring board according to the present invention. d3, the same reference numerals used in FIG. 1 indicate the same or corresponding parts. As is clear from a comparison between FIG. 2(C) and FIG. 1(d), the double-sided printed wiring board manufactured by the assembly method according to the present invention and the double-sided printed wiring board manufactured by the conventional assembly method. The board has the same appearance and configuration.

However, as described below, the manufacturing process leading to this assembled finished product is different.

First, as shown in FIG. 2(a), a double-sided printed wiring board 1
Adhesive via bonding agent 2 is applied to side A of the sheet by a printing method or the like. This manufacturing process is the same as the manufacturing process No. E shown in FIG. 1(a). Next, as shown in FIG. 2(b), the double-sided printed wiring board 1 is reversed, and an adhesive conductive bonding agent 2 is printed and coated on the B side in the same manner as in the manufacturing process shown in FIG. 2(a). . At this time, if the reversed double-sided printed wiring board 1 is supported by a jig 5 shaped so as not to come into contact with the adhesive conductive adhesive 2 applied to the A side, good printing and coating formation can be achieved. is obtained. Next, as shown in FIG. 2(C), chip components 3a, 3Lz13 and flat package IC4a are placed on side A and side B of double-sided printed wiring board 1, respectively.
, 4b, and other electronic components are temporarily placed thereon. After that,
A heat treatment is performed to simultaneously cure or melt & i-bond the adhesive conductive bonding agent 2 applied to each of the A side and the B side.

In the embodiment described above, the adhesive conductive bonding agent 2 is applied by printing on each of the A side and the B side of the double-sided printed wiring board 1, and electronic components are temporarily mounted thereon. The adhesive conductive bonding agent 2 may be printed on the A side to temporarily place the electronic components thereon, and then the adhesive conductive bonding agent 2 may be printed and applied on the 8th side and the electronic components may be temporarily placed thereon.

Further, in the above embodiment, the adhesive conductive bonding agent 2 was applied by a printing method such as screen printing 1m, but it may be applied by other methods. For example, the adhesive conductive adhesive 2 can be applied using a dispenser or by hand.

[Effects of the Invention] As described above, according to the present invention, electronic components are temporarily mounted on both sides of a double-sided printed wiring board, and then the adhesive conductive adhesives on both sides are simultaneously cured or melted. 1
The manufacturing cost can be reduced by performing the heat treatment twice. Furthermore, since the number of heat treatments is reduced compared to conventional double-sided printed wiring board assembly methods, thermal stress on printed wiring boards and electronic components can be reduced, resulting in improved quality reliability. can.

[Brief explanation of the drawing]

FIG. 1 is a diagram sequentially illustrating a conventional double-sided printed wiring board assembly method. FIG. 2 is a diagram sequentially showing a method for assembling a double-sided printed wiring board according to the present invention. In the figures, 1 is a double-sided printed wiring board, 2 is an adhesive conductive adhesive, and 3a and 3b are chip components. , 4a and 4b are flat package ICs, and 5 is a jig. Agent Masuo Oiwa Figure 1 (d)

Claims (2)

[Claims] (1) Electronic components are temporarily mounted on both sides of a double-sided printed wiring board using an adhesive conductive adhesive in advance, and then a heat treatment is performed to simultaneously harden or melt-bond the adhesive conductive adhesive on both sides. How to assemble a double-sided printed circuit board. (2) Prior to temporarily mounting the electronic components, first apply the adhesive conductive bonding agent to one side of the double-sided printed wiring board, and then apply the double-sided printed wiring board that has been reversed to the one side. The double-sided printed wiring board is coated with a 7C adhesive conductive adhesive and supported by a jig shaped so as not to come into contact with it, and the other side of the double-sided printed wiring board is coated with the adhesive conductive adhesive. A method for assembling a double-sided printed wiring board according to item 1.