JPH08172157A - Semiconductor device - Google Patents

Abstract

PURPOSE: To easily correct deformation when it is generated, by using shape- memory alloy as lead material which alloy has practically sufficient conductivity and thermal expansion coefficient approximate to that of sealing resin. CONSTITUTION: A specific number of leads 2 composed of shape-memory alloy are led out from a resin-molded package. The leads 2 are formed by molding work at a room temperature. In this case, as the shape-memory alloy, the following are used; Fe-Ni based alloy, Ti-Ni based alloy (e.g. Ti of 49.6wt.% and Ni of 50.4wt.%), and Ni-Al based alloy (e.g. Ni of 55.7wt.% and Al of 44.3wt.%). Thereby, when leads 2a, 2b of a part of the leads 2 are deformed by a cause and have abnormal forms, the deformation can be easily corrected by heating the leads at a temperature higher than the shape changing temperature.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device,
For example, it is suitable for application to a resin-sealed semiconductor device.

[0002]

2. Description of the Related Art In recent years, a semiconductor device, particularly a resin-sealed semiconductor device, is apt to be deformed during or after assembling because the lead pitch has become narrower due to the progress of miniaturization. For this reason, attention has been paid to prevent lead deformation from occurring during assembly and after handling the semiconductor device, and when lead deformation occurs, the lead deformation correcting machine corrects the deformation.

[0003]

However, when the lead deformation correction machine is used to correct the lead deformation as described above, the lead deformation correction machine is expensive to introduce and the number of semiconductor device manufacturing steps is increased. However, the manufacturing cost becomes high. In addition, since it is necessary to take extra care in handling the semiconductor device during and after assembly, it is complicated. Furthermore, on the side that uses the semiconductor device, when mounting a semiconductor device with deformed leads on the board, be careful not to cause short circuits between leads or defective soldering between the leads and the land of the board. It had to be paid and was complicated.

Therefore, it is an object of the present invention to provide a semiconductor device which can easily correct the deformation of the lead even if the deformation occurs.

[0005]

In order to achieve the above object, the present invention provides a semiconductor device having a lead,
The lead is made of a shape memory alloy.

In the present invention, basically any shape memory alloy can be used as long as it has a practically sufficient conductivity as a material of the lead, but in reality, it is a semiconductor. The most suitable one is used according to the type of device. For example, in the case of a resin-sealed semiconductor device, a shape memory alloy whose thermal expansion coefficient is as close as possible to that of the resin used is preferably used.

Some specific examples of the shape memory alloy are iron-nickel (Fe-Ni) alloys, titanium-nickel (Ti-Ni) alloys, nickel-aluminum (Ni-Al) alloys. And so on. Of these Ti-
An example of a Ni-based alloy is 49.6% by weight of Ti and 5% of Ni.
0.4% by weight, its shape change temperature is 80 ℃
Is. Further, in an example of the Ni-Al alloy, Ni is 55.
7% by weight and 44.3% by weight of Al, and the shape change temperature thereof is 60 ° C.

In one embodiment of the present invention, after forming a lead by forming a lead frame made of a shape memory alloy in a semiconductor device assembling process,
Before mounting the semiconductor device on the substrate, the lead is deformed by heating it to a temperature not lower than the shape change temperature of the shape memory alloy.

In another embodiment of the present invention, after mounting a semiconductor device on a substrate coated with a solder paste, the substrate is placed in a solder reflow furnace heated to a temperature higher than the shape change temperature of the shape memory alloy. The lead is soldered and the deformation of the lead is corrected.

Although the present invention is preferably applied to a resin-sealed semiconductor device, it can be basically applied to all semiconductor devices having a lead. The present invention is particularly preferably applied to a semiconductor device having a large number of leads such as an integrated circuit.

[0011]

According to the semiconductor device of the present invention configured as described above, since the lead is made of the shape memory alloy, the lead stores the shape of the lead frame formed by the molding process. Therefore, even if lead deformation occurs during or after assembly of the semiconductor device, the lead deformation can be easily corrected by heating the semiconductor device to a temperature not lower than the shape change temperature of the shape memory alloy.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a resin-sealed semiconductor device according to an embodiment of the present invention.

As shown in FIG. 1, in the resin-sealed semiconductor device according to this embodiment, a predetermined number of leads 2 made of a shape memory alloy are drawn out from a package 1 made of a resin mold. These leads 2 are formed by molding a lead frame made of the shape memory alloy at room temperature, for example.

In this case, the shape memory alloy is F
e-Ni-based alloy, Ti-Ni-based alloy (for example, Ti is 4
9.6 wt%, Ni 50.4 wt%), Ni-
Al-based alloy (for example, Ni 55.7 wt%, Al 4
4.3% by weight) and the like are used.

Next, a method of correcting the deformation of the lead 2 of the resin-sealed semiconductor device according to this embodiment will be described.

It is assumed that, as shown in FIG. 2, some of the leads 2a, 2b of the lead 2 are deformed for some reason and are no longer in a regular shape. Therefore, these leads 2a, 2
In order to correct the deformation of b, the resin-sealed semiconductor device is heated to a temperature higher than the shape change temperature of the shape memory alloy used as the material of the lead 2. Then, the lead 2 made of this shape memory alloy remembers the regular shape when it is formed by the molding process of the lead frame, and thus returns to this original regular shape. As a result, the deformation of the leads 2a and 2b is corrected.

If a deformation of the leads 2a, 2b is found when the resin-encapsulated semiconductor device is mounted on a substrate, the deformation can be corrected as follows.

Now, consider a case where this resin-sealed semiconductor device is soldered and mounted on a substrate by the solder reflow method. In this case, first, the resin-encapsulated semiconductor device is mounted at a predetermined position on the substrate to which the solder paste has been applied in advance, and then the substrate is passed through a solder reflow furnace.
The temperature of this solder reflow furnace is, for example, about 220 ° C., which is usually sufficiently higher than the shape change temperature of the shape memory alloy. Therefore, when the substrate is passed through this solder reflow furnace, the solder reflow occurs and the leads 2 are soldered, and at the same time, the leads 2a and 2b return to their normal shapes in the same manner as described above, and their deformation is corrected. To be done. by this,
A short circuit between the leads 2 and a soldering failure such as unbonded solder between the leads 2 and the land of the substrate are prevented, and the resin-sealed semiconductor device is reliably mounted on the substrate with high reliability.

As described above, according to this embodiment, since the leads 2 of the resin-sealed semiconductor device are made of a shape memory alloy, the leads 2 may be assembled for some reason during or after the assembly.
Even if the deformation occurs, the deformation can be easily corrected by heating the resin-sealed semiconductor device to a temperature equal to or higher than the shape change temperature of the shape memory alloy.

Further, since it is not necessary to use the lead deformation correcting machine, it is possible to prevent the manufacturing cost of the resin-sealed semiconductor device from increasing due to the use of the lead deformation correcting machine. Furthermore, since the deformation of the leads 2 can be easily corrected after the resin-sealed semiconductor device is assembled, it is necessary to take extra care when handling the resin-sealed semiconductor device during or after the assembly. Disappeared
It is easier to handle than before.

Although one embodiment of the present invention has been specifically described above, the present invention is not limited to the above embodiment, and various modifications can be made based on the technical idea of the present invention. .

For example, although the case where the present invention is applied to the resin-encapsulated semiconductor device has been described in the above-mentioned embodiment, the present invention can also be applied to, for example, a ceramic package-type semiconductor device.

[0023]

As described above, according to the present invention,
Since the lead is made of a shape memory alloy, even if the lead is deformed, the deformation can be easily corrected by heating to a temperature equal to or higher than the shape change temperature of the shape memory alloy.

[Brief description of drawings]

FIG. 1 is a perspective view showing a resin-sealed semiconductor device according to an embodiment of the present invention.

FIG. 2 is a partially enlarged perspective view showing a state in which some leads of the resin-encapsulated semiconductor device according to one embodiment of the present invention are deformed.

[Explanation of symbols]

 1 Package 2 Lead 2a, 2b Deformed lead

Claims (7)

[Claims] 1. A semiconductor device having a lead, wherein the lead is made of a shape memory alloy. 2. The semiconductor device according to claim 1, wherein the shape memory alloy is an iron-nickel alloy. 3. The semiconductor device according to claim 1, wherein the shape memory alloy is a titanium-nickel alloy. 4. The semiconductor device according to claim 1, wherein the shape memory alloy is a nickel-aluminum alloy. 5. The shape of the shape memory alloy is formed after forming the leads by forming a lead frame made of the shape memory alloy in the assembling process of the semiconductor device and before mounting the semiconductor device on a substrate. The semiconductor device according to claim 1, wherein the deformation of the lead is corrected by heating to a temperature equal to or higher than the changing temperature. 6. The semiconductor device is mounted on a substrate coated with a solder paste, and then the substrate is passed through a solder reflow furnace heated to a temperature not lower than the shape change temperature of the shape memory alloy. The semiconductor device according to claim 1, wherein the lead is soldered and the deformation of the lead is corrected. 7. The semiconductor device according to claim 1, wherein the semiconductor device is a resin-sealed semiconductor device.