JPH0613521A - Semiconductor device - Google Patents

Abstract

PURPOSE:To provide a solder-dip semiconductor device which can be soldered to a board of electric apparatuses in a stable manner. CONSTITUTION:A groove 4a is provided on an outside electrode 2 of a semiconductor device so that stabilized soldering may be performed by forming a solder fillet which comprises a solder which treats a land electrode for an electric apparatus and solders 3 and 5 which treat the outside electrode 2 for the semiconductor device.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device capable of forming a stable solder fillet on an external electrode of the semiconductor device and a land electrode of the substrate when the semiconductor device is mounted on a substrate of electric equipment.

[0002]

2. Description of the Related Art In recent years, as a trend in the industrial world, surface mounting by reflow soldering has become the mainstream method of mounting a semiconductor device on a substrate of electric equipment. The amount of solder used for the reflow solder is decreasing due to cost, environment and the like.

Solder is preliminarily attached to the external electrodes of the semiconductor device. The forming method is generally soldering by plating (solder plating) and soldering by immersing in molten solder in a solder bath or the like ( There is a solder dip).

FIG. 5 shows a conventional finished semiconductor device. FIG. 5A is a front view of the semiconductor device, which includes a package 1 encapsulating a semiconductor element and an external electrode 2 connected to the semiconductor element.

FIG. 5 (b) is a perspective view of FIG. 5 (a).
FIG. 5C shows the external electrode 2 taken along the line AB of FIG.
FIG. Here, when the external electrode 2 is subjected to the solder dip treatment, the solder 3 is thinly attached to the edge and the side surface portion of the external electrode 2.

[0006]

However, in the above conventional structure, in order to stably mount the semiconductor device on the substrate of electric equipment, the external electrode 2 of the semiconductor device has a constant thickness (5 to 5 mm) on the surface thereof.
It is necessary to uniformly apply the solder 3 of about 10 μm). With solder plating, it is possible to apply the uniform solder 3 to the external electrode 2 with a constant thickness. However, due to the nature of the solder 3, the solder dip is thinly attached to the edges and side surfaces of the external electrode 2. Therefore, the semiconductor device using the solder dip has a problem that it cannot be stably mounted on the substrate of the electric device.

It is an object of the present invention to provide a solder dip semiconductor device which can be stably mounted on a substrate of electric equipment.

[0008]

In order to achieve the above object, a semiconductor device of the present invention comprises a package and an external electrode extending from the package, and a concavo-convex structure is formed on a tip portion of the external electrode which comes into contact with a substrate. have.

[0009]

According to the structure of the present invention, since the external electrodes are provided with irregularities such as grooves, dents, holes, etc., due to the nature of the molten solder, the structure in which the solder is accumulated in the irregularities provided on the external electrodes, It has a structure that improves the solderability by widening the contact surface between the electrode and the solder that is processed on the board land electrode of the electric device, so that the semiconductor device can be stably mounted on the board of the electric device. It is possible.

[0010]

Embodiments of the present invention will be described below with reference to the drawings.

However, in order to explain the features of the present invention, the soldering state of the external electrodes is not shown in the front view and the perspective view.

FIG. 1 shows a semiconductor device according to an embodiment of the present invention. FIG. 1 (a) is a front view, FIG. 1 (b) is a perspective view, and FIG. 1 (c) is A of FIG. 1 (a). FIG. 7 is a cross-sectional view of the external electrode taken along the line B.

In FIG. 1, the semiconductor device comprises a package 1 encapsulating a semiconductor element and an external electrode 2 connected to the semiconductor element, and a groove 4a is provided at the upper end of the external electrode 2. In this embodiment, the solder 3 that is processed on the board land electrode of the electric device and the solder 3 of the external electrode 2 of the semiconductor device.
However, the groove 4a is formed in the external electrode 2 in order to form a stable fillet during reflow soldering. The groove 4a is
The external electrode 2 is mechanically or chemically formed during the manufacturing process.

The groove 4a is a tip portion of the external electrode 2 and is formed in a region which becomes flat when the semiconductor device is installed. As shown in FIG. 1C, the shape is triangular in cross section.

When the groove 4a is formed in the external electrode 2 as described above, the solder 5 is accumulated in the groove 4a during the solder dip. Since the groove 4a and the solder 5 are configured to improve the solderability of the external electrode 2 with the solder that has been processed to the land electrode of the electric device during reflow soldering, it is necessary to form a stable solder fillet. You can In other words, the groove 4a
The solder 5 and the solder 5 are configured to pull up the solder 5 processed on the board land electrode of the electric device onto the external electrode 2 during the reflow soldering.

2 (a), (b), (c) and FIG.
(A), (b), (c), and FIGS. 4 (a), (b),
(C) shows another embodiment. In each drawing, the groove described in FIG. 1 is replaced with a hole, a chip or the like, and the configuration is the same as that in FIG. Further, the same reference numerals are given to corresponding parts.

In FIG. 2, the recess 4 b is formed at the tip of the external electrode 2. The shape is formed in a semicircular shape as seen in FIG.

If the recess 4b of this embodiment is formed in the external electrode 2, the solder 5 will collect in the recess 4b during solder dipping. The recess 4b and the solder 5 are the solder and the external electrode 2 which have been treated as the land electrode of the electric device during the reflow soldering.
Since it has a structure for improving the solderability, the stable solder fillet can be formed.

In FIG. 3, recesses 4b are formed at both ends of the external electrode 2. The recess 4b is formed in a region where the external electrode 2 is bent and becomes flat when the semiconductor device is installed. As shown in FIG. 3A, the shape is a semicircular cross section formed at both ends of the external electrode 2.

When the recess 4b of this embodiment is formed in the external electrode 2, the solder 5 is accumulated in the recess 4b during solder dipping. The recess 4b and the solder 5 are the solder and the external electrode 2 which have been treated as the land electrode of the electric device during the reflow soldering.
Since it has a structure for improving the solderability, the stable solder fillet can be formed.

In FIG. 4, a hole 4c that is hollowed out in a circle is formed in a region where the external electrode 2 is bent and becomes flat when the semiconductor device is installed.

When the hole 4c of this embodiment is formed in the external electrode 2, the solder 5 is accumulated in the hole 4c during the solder dip. Since the holes 4c and the solder 5 are configured to improve the solderability of the external electrode 2 with the solder treated on the land electrode of the electric device at the time of reflow soldering, a stable solder fillet should be formed. Can be done.

By increasing the number of grooves, depressions, holes, etc., as compared with the above-described embodiment, the effect of the embodiment can be made more remarkable, and it can be used in a semiconductor device for solder plating. is there.

[0024]

As described above, the groove according to the present invention,
By forming protrusions and depressions such as dents and holes in the external electrodes of the semiconductor device, it becomes possible for the external electrodes of the semiconductor device having the solder dip to form a stable solder fillet with the board land electrodes of the electric device.

[Brief description of drawings]

1A is a front view of an embodiment of a semiconductor device of the present invention, FIG. 1B is a perspective view thereof, and FIG. 1C is a sectional view taken along the line AB of FIG.

2A is a front view of another embodiment of the semiconductor device of the present invention, FIG. 2B is a perspective view thereof, and FIG. 2C is a cross-sectional view taken along the line AB of FIG.

3A is a front view of yet another embodiment of the semiconductor device of the present invention, FIG. 3B is a perspective view thereof, and FIG. 3C is a sectional view taken along the line AB of FIG.

4A is a front view of yet another embodiment of the semiconductor device of the present invention, FIG. 4B is a perspective view thereof, and FIG. 4C is a sectional view taken along the line AB of FIG.

5A is a front view of a conventional semiconductor device, FIG. 5B is a perspective view thereof, and FIG. 5C is a cross-sectional view taken along line AB of FIG.

[Explanation of symbols]

 1 Package 2 External Electrode 3 Solder 4a Groove 4b Recess 4c Hole 5 Solder

Claims (1)

[Claims] 1. A semiconductor device comprising a package and an external electrode extending from the package, wherein a tip portion of the external electrode in contact with the substrate has an uneven structure.