JPH04312964A - Semiconductor device - Google Patents

Abstract

PURPOSE:To reduce deterioration of a soldered part of a lead of a semiconductor device to a circuit board due to a thermal stress by increasing the width of a position at which the lead is extended, the wider the separated more separated the lead from the central position of a resin-molded package. CONSTITUTION:A semiconductor device 1 has a plurality of leads 30-33 extended from both ends of a resin-molded package 2, and the leads 30-33 are soldered to a circuit board 4. However, A3>A2>A1>A0 is satisfied, where A0 is the width of two leads 30 extended from both right and left end positions nearest the central position O of the package 2, A1 is the width of the four leads 31 extended from both right and left end positions near the position O, A2 is the width of the four leads extended from both the right and left end positions near the position O, and A3 is the width of the four leads 33 extended from both the right and left end positions near the position O.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device surface-mounted on a circuit board.

0002

2. Description of the Related Art FIG. 3 shows a conventional surface-mount type semiconductor device 10. In the figure, 2 is a resin molded package, and 3 is a plurality of leads led out from both ends of this package 2. Each lead 3 of this semiconductor device 10 has the same width A and is formed with the same pitch interval B.

This semiconductor device 10 is mounted by soldering the hatched portions (lead width A×soldering length C) of the plurality of leads 3 to a circuit board 4 as shown in FIG. In addition, in FIG. 4, 5 is a soldered part.

0004

[Problems to be Solved by the Invention] When a temperature cycle test is performed after the semiconductor device 10 is mounted on the circuit board 4 in this manner, it is found that the coefficient of linear expansion of the circuit board 4 is lower than that of the resin mold package 2 and the leads 3. Because of its small size,
Thermal stress will occur in the soldered portion 5 of the lead 3, and this thermal stress will occur at positions away from the center position O of the resin molded package 2 (upper and lower sides in FIG. 3).
The problem is that the lead 3 becomes larger and the soldered portion 5 of the lead easily deteriorates.

The present invention has been made in view of the above-mentioned points, and an object of the present invention is to reduce deterioration due to thermal stress of the soldered portion between the lead of a semiconductor device and a circuit board.

[0006]

[Means for Solving the Problems] In order to achieve the above-mentioned object, the present invention is constructed as follows.

That is, the present invention provides a surface mount type semiconductor device having a plurality of leads led out from both ends of a resin molded package, and in which the leads are soldered to a circuit board, in which the positions where the leads are led out are , the width of the leads is made wider as they are farther away from the center of the resin molded package.

[0008]

[Function] According to the above structure, the lead-out position is wider as the leads are farther away from the center position of the resin molded package, so the soldering area with the circuit board is also increased accordingly. In the temperature cycle test, the thermal stress of the soldered portion of the lead at a position away from the center position is reduced compared to the conventional example.

[0009]

Embodiments Hereinafter, embodiments of the present invention will be explained in detail with reference to the drawings.

FIG. 1 shows a semiconductor device 1 according to an embodiment of the present invention.
FIG. 2 is a front view thereof, and parts corresponding to the conventional example described above are given the same reference numerals.

The semiconductor device 1 of this embodiment has a plurality of leads 30 led out from both ends of the resin mold package 2.
33, and these leads 30 to 33 are of a surface mount type in which these leads 30 to 33 are soldered to the circuit board 4 in the same manner as in the conventional example shown in FIG.

In this embodiment, in order to reduce the deterioration of the soldered parts due to thermal stress in the temperature cycle test, the positions from which the leads 30 to 33 are led out gradually change as the distance from the central position O of the resin mold package 2 increases. The widths A0 to A3 of the leads 30 to 33 are widened.

That is, the width of the two leads 30 led out from the left and right end positions closest to the center position O of the resin molded package 2 is A0, and then the width is set to the center position O.
A1 is the width of the four leads 31 that are respectively led out from the left and right end positions near the center position O, and A2 is the width of the four leads 32 that are each led out from the left and right end positions that are near the center position O. Next, if the width of the four leads 33 respectively derived from the left and right end positions near the center position O is A3, then A3>A2>A1>A0.

Note that the pitch interval B of each lead 30 to 33 is
And the soldering length C is the same as the conventional one.

In this embodiment, the further the leads 30 to 33 are from the center position O of the resin mold package 2, the larger the soldering area shown by diagonal lines. Thermal stress on the soldered portion of the lead at the position is reduced compared to the conventional example, and deterioration of the soldered portion is suppressed.

Furthermore, since the leads 30 to 33 located at the ends of the resin molded package 2 have a wider width, deformation of the leads 30 to 33 is less likely to occur and the soldering to the circuit board 4 is stabilized. This means that you can do it.

Although the above-described embodiments have been described with reference to gull-wing type leads, it is of course applicable to J-bend type leads as well.

Although the above-described embodiment has been described with reference to the semiconductor device 1 in which the resin mold package 2 is symmetrical, the present invention can similarly be applied even if the resin mold package 2 is asymmetrical based on the distance from the center position.

[0019]

As described above, according to the present invention, the lead-out position is wider as the leads are farther away from the center position of the resin molded package, so that the leads farther from the center position are closer to the circuit board. The soldering area becomes larger,
As a result, the thermal stress on the soldered portions of the leads located away from the center position is reduced compared to the conventional example, and deterioration of the soldered portions can be suppressed.

[Brief explanation of drawings]

FIG. 1 is a plan view of an embodiment of the present invention.

FIG. 2 is a front view of the embodiment of FIG. 1;

FIG. 3 is a plan view of a conventional example.

FIG. 4 is a diagram showing a semiconductor device mounted on a circuit board.

[Explanation of symbols]

1,10 Semiconductor device 2
Resin mold package 3, 30-3
3 lead

Claims (1)

[Claims] 1. A surface mount type semiconductor device having a plurality of leads led out from both ends of a resin molded package, the leads being soldered to a circuit board, comprising:
A semiconductor device characterized in that a position from which a lead is led out is wider as the lead is farther away from the center of a resin molded package.