JPH04315465A - Surface mounting type semiconductor device - Google Patents

Abstract

PURPOSE:To provide a surface mounting type semiconductor device, in which thermal stress is prevented from acting concentrically only upon a solder part for connecting an input/output lead terminal and wiring pattern so that it is possible to absorb the thermal stress to contrive to improve reliability, even if the thermal stress is generated on the basis of the fact that a package constituting the surface mounting type semiconductor device and a circuit substrate, on which this semiconductor device is mounted, have coefficients of thermal expansion differing from each other. CONSTITUTION:A surface mounting type semiconductor device 1 is equipped with a package 11 formed into a rectangle in a plan view, input/output lead terminals 12 are extended from respective one side two lateral surfaces facing each other of this package 11, and fixing lead terminals 2 are extended from respective other side two lateral surfaces facing each other of said package 11.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface mount type semiconductor device such as a hybrid IC, and more particularly to a surface mount type semiconductor device having a structure in which lead terminals extend from each side surface of a package.

0002

2. Description of the Related Art Hitherto, as this type of surface mount type semiconductor device, one having an external structure as shown in FIG. 2 has been known. Then, this surface mount type semiconductor device 10
comprises a semiconductor element (not shown) and a rectangular package 11 in a plan view made of a molded resin that houses and seals the semiconductor element. A predetermined number of input/output lead terminals 12 are extended outward. Then, when mounting this surface mount type semiconductor device 10,
Input/output lead terminals 12 extending from the package 11
It is common practice to connect the downwardly bent outer end portions of each to a wiring pattern (not shown) formed on a circuit board by soldering.

0003

However, the surface-mounted semiconductor device 10 having the conventional structure has the following disadvantages. That is, the surface-mounted semiconductor device 1
0 is mounted on a circuit board and then a reliability test such as a heat cycle test is performed. The action is concentrated on the solder portion (not shown) that connects the outer end of the input/output lead terminal 12 and the wiring pattern, and cracks may occur in this solder portion. As a result, the reliability of the surface-mounted semiconductor device is actually impaired due to the reliability test.

The present invention was devised in view of these disadvantages, and is capable of absorbing thermal stress generated due to the difference in thermal expansion coefficients of the package and the circuit board, thereby improving reliability. The purpose of the present invention is to provide a surface-mounted semiconductor device that can improve the performance.

[0005]

[Means for Solving the Problems] A surface-mounted semiconductor device according to the present invention includes a package having a rectangular shape in plan view, and input/output lead terminals are provided from each of two opposing sides of the package. The package is characterized in that fixing lead terminals are extended from each of the other two opposing sides of the package.

[0006]

[Operation] According to the above structure, both the input/output lead terminals and the fixing lead terminals extending from the package are soldered and connected to the wiring pattern on the circuit board. Thermal stress that occurs due to the difference in thermal expansion coefficient between the input and output lead terminals and the wiring pattern is no longer concentrated only on the solder part that connects the input/output lead terminal and the wiring pattern, and the fixing lead terminal is located along the direction perpendicular to these. It also acts in a distributed manner on the solder portions that connect the wiring patterns.

[0007]

Embodiments Hereinafter, embodiments of the present invention will be explained based on the drawings.

FIG. 1 is a perspective view showing the external structure of a surface-mounted semiconductor device according to this embodiment, and reference numeral 1 in this figure indicates a surface-mounted semiconductor device such as a hybrid IC. Note that since the basic structure of this surface-mounted semiconductor device 1 is the same as that of the conventional example, FIG.
Components and portions that are the same as each other are given the same reference numerals.

Surface-mounted semiconductor device 1 according to this embodiment
The device includes a semiconductor element (not shown) and a rectangular package 11 in plan view made of a molded resin that houses and seals the semiconductor element. A predetermined number of input/output lead terminals 12 extend outward from each of the two opposing sides of the package 11, and each input/output lead terminal 12 is bent downward. The outer end portion is formed on a circuit board and is connected to a corresponding wiring pattern (none of which is shown) by soldering.

Furthermore, in this surface mount type semiconductor device 1, the other two of the packages 11 facing each other are
Fixing lead terminals 2 having no electrical function are also extended from each side surface. The outer ends of each of these fixing lead terminals 2, which are bent downward, are similar to the outer ends of the input/output lead terminals 12.
They are connected by soldering to dummy wiring patterns (none of which are shown) formed at corresponding positions on the circuit board. In addition, in Figure 1,
Although each of the fixing lead terminals 2 is in the shape of a single plate, it goes without saying that the lead terminals 2 may have a shape divided into a plurality of pieces. Further, in FIG. 1, the fixing lead terminal 2 and the input/output lead terminal 12 have a gull-wing shape, but it goes without saying that they may be J-shaped or the like.

That is, in this surface mount type semiconductor device 1, the fixing lead terminal 2 extending from the package 11 is soldered and connected to the wiring pattern on the circuit board together with the input/output lead terminal 12. Become. Therefore, the thermal stress generated when performing a reliability test such as a heat cycle test after mounting the surface mount semiconductor device 1 on a circuit board is applied only to the solder portion connecting the input/output lead terminal 12 and the wiring pattern. It no longer acts in a concentrated manner, but instead acts in a distributed manner on the solder portion connecting the fixing lead terminal 2 and the wiring pattern.

0012

As explained above, according to the surface-mounted semiconductor device of the present invention, both the input/output lead terminals and the fixing lead terminals extending from the package can be soldered to the wiring pattern on the circuit board. Since these are connected together, the thermal stress generated based on the difference in the thermal expansion coefficients of the package and the circuit board will be applied to the solder parts that connect the input/output lead terminals and fixing lead terminals to the wiring pattern. It will act in a distributed manner. Therefore, it is impossible for thermal stress to concentrate and act only on the solder part that connects the input/output lead terminal and the wiring pattern, as in the conventional example, and it is possible to absorb the generated thermal stress. As a result, it is possible to improve the reliability of the surface-mounted semiconductor device.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing the appearance of a surface-mounted semiconductor device according to an embodiment.

FIG. 2 is a perspective view showing the appearance of a conventional surface-mounted semiconductor device.

[Explanation of symbols]

1　　　　Surface mount type semiconductor device 2 Fixed lead terminal 11 Package 12 Input/output lead terminal

Claims (1)

[Claims] 1. A surface-mounted semiconductor device comprising a package having a rectangular shape in plan view, and input/output lead terminals extending from each of two opposing sides of the package, A surface-mounted semiconductor device characterized in that fixing lead terminals extend from each of the other two opposing sides of the package.