JPH03169058A - Semiconductor device - Google Patents

Abstract

PURPOSE:To absorb a thermal stress of a solder connection part by a method wherein leads are curved at intermediate parts of the leads protruding from a package. CONSTITUTION:Leads 2a which protrude horizontally from a package 1 are bent at a first bend part 3 in a prescribed size position (e.g. about 0.5 to 2mm) toward the upper part. In succession, they are bent at a first return part 4 and are stretched in a horizontal direction by a prescribed size (e.g. about 1 to 3mm); they are again bent perpendicularly downward at a second bent part 5. When curved bend and return parts are formed between roots and tips of the leads 2a, the curved bend and return parts have spring property and absorb a stress caused by heat.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a semiconductor device, and particularly to the shape of a lead that protrudes from the outer body of a semiconductor device. [Prior Art] FIGS. 3(a), (b), and (c) are a plan view, a side view, and a partially enlarged side view showing an example of a conventional semiconductor device, and FIGS. 4(a) and (b) are FIG. 2 is a side view and a partially enlarged side view showing another example of a conventional semiconductor device. Conventionally, this type of semiconductor device has, for example, as shown in FIGS. 3(a), (b), and (C), an outer shell 1 enclosing a semiconductor chip and an input/output terminal of the semiconductor chip connected to each other. , and the lead 2 protruding from the side surface of the outer shell 1. Also, the lead 2
protrudes from the outer body 1 and is located at a position of a predetermined size, for example 9
In another semiconductor device, as shown in FIGS. 4(a) and (b), the tip of the lead 2 was bent back and the tip of the lead 2 was bent back. is formed parallel to the bottom surface of the outer body 1.Some devices have leads called so-called gull wings.When such a semiconductor device is mounted on a printed board,
Although not shown in the drawings, each lead was positioned on a pad corresponding to the lead on the printed circuit board, and the semiconductor device was fixed and connected by soldering.

[Problem to be solved by the invention]

However, in the conventional semiconductor device described above, not only are the leads bent at only one place and the leads are short, but the leads themselves do not have a means to absorb thermal stress, and the solder joints between the printed board and the leads are exposed to thermal stress. is concentrated. Therefore, for example, a lead with a butt lead shape as shown in FIG. 3 has the disadvantage that the connecting portion is small and may break due to thermal stress. In addition, with gull-wing shaped leads as shown in Figure 3, the connection part is large, so it seems to have sufficient strength, but solder creeps up (solder sticks tightly to the side of the lead due to capillary action). The problem is that cracks are likely to occur at the interface between the solder and the lead surface, and cracks occur even if there is a time difference.The purpose of the present invention is to eliminate these drawbacks and provide a highly reliable semiconductor device. [Means for Solving the Problems] In the semiconductor device of the present invention, a lead extending in one direction from a side surface of an outer shell is bent and folded back by a device having a predetermined size, and a lead extending in the same direction as the one direction is provided. It is characterized in that the tip of the lead is bent at a predetermined angle with respect to the one direction.

[Example] Next, the present invention will be explained with reference to the drawings. FIGS. 1(a), (b), and (C) are a plan view, a side view, and a partially enlarged side view of a semiconductor device showing one embodiment of the present invention. As shown in the figure, in this semiconductor device, a lead 2a that protrudes horizontally from an outer body 1 is directed substantially upward at a predetermined dimensional position (for example, about 0.5 to 2''''''). It is bent at the first folding part 3, then bent at the first folding part, extended horizontally by a predetermined dimension (for example, about 1 to 31), and then downward at a right angle again at the second folding part 5. This means that it is bent.

In this way, by providing a curved folded portion between the base and the tip of the lead 2a, this bent portion has spring characteristics and absorbs stress due to heat. 2(a) and (b) are a side view and a partially enlarged side view of a semiconductor device showing another embodiment of the present invention.As shown in the figure, this semiconductor device is similar to the above-described semiconductor device. The lead shown in the embodiment is further provided with a first folded folded part 6 and a second folded folded part 7, thereby adding one more folded folded part. This has the advantage of reducing the spring constant and being able to absorb even a small stress.In this example, a butt reed was used as an example, but it is clear that it can also be applied to a gull-wing reed. [Effects of the Invention] As explained above, the present invention provides a curved part in the middle of the lead protruding from the outer shell, and uses a spring as a stress absorbing means, thereby reducing thermal stress from the soldered joint. The effects of heat stress can be interfered with by leads.The period of withstanding thermal stress is significantly extended, resulting in a semiconductor device that can maintain high quality for a long period of time.

[Brief explanation of the drawing]

Figure 1(a). (b) and (C) are a plan view, a side view, and a partially enlarged side view of a semiconductor device showing one embodiment of the present invention;
2(a) and 2(b) are a side view and a partially enlarged side view of a semiconductor device showing another embodiment of the present invention; FIG. 3(a),
(b) and (C) are a plan view, a side view, and a partially enlarged side view showing an example of a conventional semiconductor device, and FIGS. 4(a) and (b)
) FIG. 2 is a side view and a partially enlarged side view showing another example of a conventional semiconductor device. 1... Outer body, 2.2a, 2b... Lead, 3.
...First folded part, 4...First folded part, 5
... second folding part, 6... first folding part, 7... second folding part.

Claims (1)

[Claims] A lead extending in one direction from the side surface of the outer body is bent back using a device having a predetermined size, extends in the same direction as the one direction, and the tip of the lead is bent again at a predetermined angle with respect to the one direction. A semiconductor device characterized by: