JPH09223769A - Solder terminal - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] Solder for soldering with increased reliability without causing a solder bridge between terminals even for surface-mounting electric components in which a large number of soldering terminals are arranged at a narrow pitch. Provide terminals. A soldering terminal (4) is provided between a flat portion (43) parallel to a pad (2a) of the wiring substrate (2) at a tip portion to be soldered to the wiring substrate (2) and a flat portion (43) by folding the tip end side of the flat portion (43). The folded portion 44 that forms the gap portion 45 in the
And a through hole 43a communicating with the gap portion 45 is formed in the flat portion 43.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric component mounting means, and more particularly to an improvement of a soldering connection structure between a terminal of a surface mounting electric component and a wiring board.

[0002]

2. Description of the Related Art Recently, as a means for mounting electric parts on a wiring board, terminals provided on the electric parts are directly soldered to pads formed on the wiring board so that electrical connection can be made simultaneously with mechanical connection. The number of people who also carry out static fixation has increased. That is, as shown in FIG. 6, surface mounting electrical components (hereinafter referred to as electrical components) 1 such as connectors and ICs mounted on the wiring substrate 2 are extended from both side surfaces of the main body 11 and the pads 2 a of the wiring substrate 2 are provided.
It has a plurality of soldering terminals 12 to be soldered to.
The soldered terminal 12 is bent by a press work in the vicinity of the side surface of the main body 11 and extends downward, and a leg portion 12a and a leg portion 1 are provided.
The flat portion 12b is formed so as to be parallel to the surface of the wiring substrate 2 by bending the tip end portion of the wiring portion 2a outward at a substantially right angle. The surface of the soldering terminal 12 is plated with nickel or the like, and then plated with solder in order to improve soldering. In order to mount such an electric component 1 on the wiring board 2, after the flat portion 12b is superposed on the pad 2a of the wiring board 2 on which the paste-like solder is applied, soldering connection is performed by a vapor phase or the like. It was mechanically fixed at the same time as the physical connection.

[0003]

By the way, the electric component 1
As the number of soldering terminals 12 arranged in the main body 11 increases due to the complexity and sophistication of the terminals, the pitch between the terminals becomes narrower, and correspondingly, the pads 2a arranged on the wiring board 2 side are arranged. The intervals will also be narrower. Therefore, as shown in FIG. 7, when the flat portion 12b of the soldering terminal 12 is soldered to the pad 2a of the wiring board 2, the solder fillet 3a formed by the molten solder and wrapping around the side surface of the flat portion 12b, There is a possibility that a solder bridge may be formed by connecting the adjacent soldered terminals 12 to each other. If the amount of solder is reduced in order to prevent this, the soldering terminal 12 is not reliably soldered to the pad 2a, and there is a drawback that the reliability of the solder connection portion is reduced. Therefore, the present invention provides a soldering terminal that can be soldered with increased reliability without causing a solder bridge between the terminals, even in the case of a surface mounting electric component in which a large number of soldering terminals are arranged at a narrow pitch. .

[0004]

According to the present invention, there is provided a soldering terminal projecting from a surface-mounting electric component and soldered to a wiring board, wherein the soldering terminal is mounted on the wiring board at a tip portion thereof. A flat part parallel to the pad surface of
A folded-back portion is provided to form a gap between the flat portion and the flat portion by folding back the tip side, and a through hole communicating with the gap is formed in the flat portion. When the soldering terminal configured as described above is soldered to the pad surface of the wiring board, the molten solder existing between the soldering surface of the flat portion and the pad passes through the through hole due to the effect of surface tension. It also flows into the gap. As a result, the amount of molten solder that wraps around the side surface of the flat portion is reduced as compared with the conventional example, so that a soldered terminal that does not cause a solder bridge between the terminals arranged in the electric component can be obtained.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a perspective view showing a state in which an electric component in which the soldering terminals of the present invention are arranged is mounted on a wiring board, FIG. 2 is an enlarged perspective view of an essential part of the soldering terminal, and FIG. 3 shows a soldering terminal and a wiring board. FIG. 3 is an enlarged perspective view showing a soldered portion of FIG. FIG. 1 is a diagram in which the soldering terminal 4 of the present invention is applied to the electric component 1 shown in FIG. 6. Like the conventional example, the soldering terminal 4 is formed in a flat plate shape, and the surface thereof is plated with nickel or the like. After that, solder plating is applied. The soldering terminal 4 includes a horizontal portion 41 that horizontally protrudes from the side surface of the main body 11 of the electrical component 1, a leg portion 42 that extends downward by bending the tip portion of the horizontal portion 41 at a substantially right angle, and a tip portion of the leg portion 42. The wiring board 2
Flat portion 43 extending parallel to the pad 2a surface of
It is composed of a folded-back portion 44 formed by folding back the tip of 3 in a substantially U-shape. The folded-back portion 44 is a gap portion between the curved portion 44 a that is bent in a direction in which the tip end side of the flat portion 43 is separated from the wiring board 2, and the flat portion 43 that extends from the curved portion 44 a so as to face the upper surface of the flat portion 43. It consists of an extension 44b forming 45. Also, the extension 4 of the flat portion 43
A through hole 43a is formed in the plate surface facing 4b, and the gap portion 45 and the soldering surface of the flat portion 43 communicate with each other through the through hole 43a.

Next, in order to mount the electric component 1 on the wiring board 2, the flat portion 43 of the soldering terminal 4 configured as described above.
When soldering is performed by superposing the soldering surface of the pad 2a on the pad 2a of the wiring board 2, since the flat portion 43 is preliminarily solder-plated, the wettability of the paste solder of the pad 2a is good. Therefore, the solder plating and the paste-like solder are melted and integrated, and spread between the flat portion 43 and the pad 2a.
Then, as shown in FIG. 3, the molten solder is applied to the leg 4 of the flat portion 43.
The gap 46 between the surface continuous to the second side and the pad 2a and the gap 47 between the surface continuous to the curved portion 44a and the pad 2a are simultaneously entered, and at the same time, the through hole of the flat portion 43 is caused by the surface tension of the molten solder. When the solder flows into the gap 45 through the gap 43a and is solidified by cooling, the solder fillets 5a and 5b are formed in the gaps 46 and 47, and the gap 45 and the through hole 4 are formed.
A solder layer 5c is formed on 3a. As described above, in the terminal structure of the present invention, the molten solder interposed between the flat portion 43 and the pad 2a is sucked into the gap portion 45 through the through hole 43a provided in the flat portion 43. It becomes difficult to turn to. As a result, since the solder fillet 3a shown in the conventional example does not become large on the side surface of the flat portion 43, it is possible to prevent a solder bridge from being generated by the solder fillet 3a between adjacent terminals. Next, FIG. 4 shows an example in which the plating on both side surfaces of the flat portion 43 of the soldering terminal 4 is removed by post-processing to expose the conductor surface of the soldering terminal 4. As a result, both side surfaces 43b, 43b of the flat portion 43 are
Since the wettability of the solder is worse than that of the other surface plated with solder, it is difficult to form a solder fillet in this portion. In addition, in the above-mentioned embodiment, the through hole 43a is formed in the flat portion 43 to allow the solder to enter the gap 45. However, as shown in FIG.
3a in place of the slit 61 for the flat portion 43 and the curved portion 44a.
Alternatively, it may be provided over the extended portion 44b.
Further, in the flat portion 43 facing the extension portion 44b, the gap 4
It is also possible to provide the recess 62 in order to increase the amount of solder entering the inside of the wiring 5.

[0007]

As is apparent from the above description, the soldered terminal according to the present invention has a gap portion formed between the soldered terminal according to the present invention and the flat portion to be soldered to the wiring board by folding back the tip end portion,
In addition, the flat portion is provided with a through hole that connects the soldering surface and the gap portion. When soldering the soldering terminal configured in this way to the wiring board, the molten solder that is interposed between the soldering surface of the flat part and the wiring board is sucked into the gap through the through hole. It is possible to prevent the solder from wrapping around the side surface of the flat portion. Accordingly, it is possible to prevent the formation of a solder bridge between the terminals arranged in the electric component, and to provide a soldered terminal that is soldered to the wiring board with increased reliability.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention and showing a state in which surface mounting electric components are attached to a wiring board.

FIG. 2 is an enlarged perspective view of a part of the soldering terminal in FIG.

FIG. 3 is an enlarged perspective view of a main part of FIG.

FIG. 4 is a sectional view for explaining a soldering terminal of the present invention.

FIG. 5 is an enlarged perspective view of a part of another embodiment.

FIG. 6 is a perspective view showing a conventional example in which surface mounting electric components are attached to a wiring board.

7A is a front view of a main part of FIG. 6, and FIG. 7B is a side view of a main part of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electric component 12,4 Soldering terminal 12b, 43 Flat part 43a Through hole 44 Folding part 45 Gap part 61 Slit

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Masayuki Kikuchi 1-22-1 Dogenzaka, Shibuya-ku, Tokyo Japan Aviation Electronics Industry, Ltd. No. 6 Yamagata Aviation Electronics Co., Ltd.

Claims (3)

[Claims] 1. A soldering terminal projecting from a surface-mounting electrical component and soldered to a wiring board, wherein the soldering terminal has a flat portion parallel to a pad surface of the wiring board at a tip portion to be soldered to the wiring board. And a folded-back portion that forms a gap between the flat portion and the flat portion by folding back the tip end side of the flat portion, and a through hole that communicates with the gap is formed in the flat portion. And soldered terminals. 2. The soldered terminal according to claim 1, wherein a slit replacing the through hole is formed from the flat portion to the folded portion. 3. The plating is removed from both side surfaces of the flat portion to expose the conductor.
Soldered terminal described.