JPS61256792A - Printed wiring board device - 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 the Invention The present invention relates to a printed wiring board device used in electronic equipment, etc., and particularly in reflow soldering in which the back side of a component soldering land is heated and the printed wiring board is sequentially conveyed. Concerning improvement of soldering quality of soldering land.

Conventional technology In recent years, as electronic devices and other devices have become smaller and lighter, thin printed wiring board devices have been used and chip-like parts have become more compact and lighter.
0 - Attachment by soldering is increasing.

Generally, in order to improve the solderability in the reflow soldering method for chip-shaped parts, it is necessary to
This is done by making the component soldering lands 22 & 22b independent of the other copper foils 25 to prevent heat release, and by adjusting the temperature conditions and time settings to each printed wiring board 21. This is done by arranging component soldering lands 220 perpendicular to the heating direction.

The problem that the invention aims to solve However, like this, the component soldering land 22a.

Even if 22b is made independent, the temperature conditions and time settings are the same, the soldering land 22 of component 26! L and 22b
is heated and cooled in a direction close to the heating direction, so a time lag in temperature occurs between the component soldering lands 22 & 22b, which causes the chip-shaped component 26 to move toward the heating direction, causing other There may be a short circuit with the component soldering land, or the component soldering land 22 on the heating direction side as shown in Figure 4! L solder 2
There was a problem in that the chip-shaped component 26 stood up due to the attractive force during the curing of the soldering device 4, resulting in poor soldering.

Also, all the chip-shaped parts 26 are aligned perpendicularly to the heating direction.
In order to arrange this, a considerably large mounting space is required, which poses the problem of poor mounting efficiency in high-density mounting.

The present invention solves these conventional problems.
An object of the present invention is to provide an excellent printed wiring board device that can improve the soldering quality of chip-shaped components in a reflow soldering method.

Means for Solving the Problems The printed wiring board device of the present invention is directed to the progress of reflow soldering of the electrodes of the chip-shaped parts when a chip-shaped part having a plurality of electrodes is attached to the printed wiring board by reflow soldering. A copper foil land having the same shape as the soldering land is arranged at the same position on the back surface of the soldering land of the electrode on the forward side in the direction.

Function: When a chip-shaped component having a plurality of electrodes is attached to a printed wiring board by reflow soldering, the printed wiring board device of the present invention removes the solder of the electrode on the forward side in the direction of movement during reflow soldering of the electrodes of the chip-shaped component. A copper foil land with the same shape as the soldering land placed at the same position on the back side of the soldering land is heated, and the heat is uniformly transmitted to the soldering land on the opposite side, and the heat retention effect of the copper foil land on the back side allows the soldering land on the opposite side to stay on the opposite side for a long time. Maintains the temperature of component soldering lands and eliminates temporal differences in temperature between component soldering lands on a single chip component.
The soldering quality of component soldering lands can be improved.

Embodiment FIG. 1 shows an embodiment of the present invention, and FIG. 2 shows a sectional view thereof. A copper foil land 3 having the same shape as the component soldering land 21L is arranged at the same position on the back surface of the component soldering land 2& of the electrode 71L on the forward side in the direction of movement of the chip-like component 6 on the printed wiring board 1. Such a printed wiring board device has component soldering lands 2&, as shown in Fig. 2.
When reflow soldering is performed by heating 2b sequentially from its back side in the direction of movement, the copper foil land 3 on the back side of the component soldering land 2a is heated first, and the entire copper foil land 3 is heated to a uniform temperature. Because of its good heat retention effect, it can serve as a uniform and long-term heat source. Therefore, the entire component soldering land 21L on the opposite side is heated uniformly, and in addition, in order to maintain the temperature for a long time, the temperature difference in temperature between the component soldering lands 2a and 2b is reduced, and the solder 4 is heated uniformly. Hardening occurs almost simultaneously. Therefore, it is desirable to improve the soldering quality of the chip-shaped component 70 to the component soldering lands 2a and 2b. In addition, chip transistors and ICs with three electrodes are also used.
It goes without saying that the same can be realized in multi-legged parts such as the following.

Effects of the Invention The present invention provides a method for attaching a chip-shaped component having a plurality of electrodes to a printed wiring board by reflow soldering, and the back surface of the soldering land of the electrode on the forward side in the direction of movement during reflow soldering of the electrodes of the chip-shaped component. Since a copper foil land with the same shape as the soldering land is placed at the same position, this copper foil land is heated and the heat is transmitted evenly and for a long time to the component soldering land on the opposite side as a heat source, and the component soldering land is heated. It is possible to realize an excellent printed wiring board device that can reduce the temporal deviation in temperature between lands and thereby improve the soldering quality of chip-shaped components.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a printed wiring board device according to an embodiment of the present invention, FIG. 2 is a cross-sectional view of the same board with chip-shaped components mounted thereon, and FIG. 3 is a plan view of a conventional printed wiring board device. , FIG. 4 is a sectional view after reflow soldering of chip-shaped components in a conventional printed wiring board device. 1...Printed wiring board, 21L, 2b/old/
・Component soldering land, 3...:・Copper foil land (back side of component soldering land), 4... Solder, 6...
...Copper foil (component soldering land side), 6... Chip-shaped component, 71L, 7b... Chip-shaped component electrode. Name of agent: Patent attorney Toshio Nakao and 1 other person/-
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! 1) 21-7°〉Lshi: *iru (2C---chi,)・Guzushashi 1 27---person! Preference 2e---,, solder H rashi)' 2c

Claims (1)

[Claims] When a chip-like part having a plurality of electrodes is attached to a printed wiring board by reflow soldering, the soldering is applied to the same position on the back side of the soldering land of the electrode on the forward side in the direction of movement during reflow soldering of the electrodes of the chip-like part. A printed wiring board device characterized in that a copper foil land having the same shape as the land is arranged.