JPH0575007A - Resin-sealed semiconductor device - Google Patents

Abstract

(57) [Summary] [Object] To provide a technique capable of improving the moisture resistance of a package in a resin-sealed semiconductor device. In a resin-sealed semiconductor device in which a semiconductor chip is mounted on a tab, the lead and the semiconductor chip are electrically connected and sealed with a molding resin, the tab and the tab suspension lead are different from the lead. Composed of materials. [Effect] When the package is surface-mounted on the substrate, water vapor generated at the interface between the tab and the resin due to the moisture absorbed by the mold resin is transmitted to the outside through the tab suspension leads, so that moisture absorbed by the mold resin is vaporized. Along with this, the stress acting on the interface between the mold resin and the semiconductor chip is relaxed, and it is possible to reduce package cracks and deterioration of adhesion between the mold resin and the surface of the semiconductor chip and between the mold resin and the leads.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin-encapsulated semiconductor device, and more particularly to a technique effectively applied to a package of a resin-encapsulated semiconductor device.

[0002]

2. Description of the Related Art In recent years, due to the demand for miniaturization of electronic equipment, miniaturization and thinning of semiconductor devices have been remarkable. With the recent miniaturization and thinning, the time required for the moisture concentration on the surface of the semiconductor chip to reach a saturation value becomes very short. In the surface mount package, when the product is mounted on the board, the temperature of the entire resin-sealed semiconductor device (package) becomes high, so a gap is created at the interface due to the difference in the thermal expansion coefficient of the constituent materials, and the mold resin such as resin And the leads and between the mold resin and the surface of the semiconductor chip deteriorate. In particular, when the mold resin absorbs moisture during storage before mounting, the absorbed moisture is vaporized by the heat during mounting to expand into steam, and a large force acts between the semiconductor chip surface and the mold resin. As a result, the adhesiveness between the mold resin rack or the lead and the mold resin, and the adhesion between the semiconductor chip and the mold resin are likely to deteriorate.

For example, when mounting a small outline package on a substrate, the infrared reflow method VPS method, which has high mass productivity, is often used. With this method of mounting the product on the board, the entire package becomes hot, so
A gap is created at the interface due to the difference in the coefficient of thermal expansion of the constituent materials, and the adhesion between the mold resin and the leads and between the mold resin and the surface of the semiconductor chip deteriorates. In particular, when the mold resin absorbs moisture during storage before mounting, this absorbed moisture is vaporized by the heat during mounting and becomes water vapor, which gives pressure to the material interface and is a major cause of poor adhesion. .

Therefore, a structure is applied to the surface portion of the island support of the plastic IC so as to reduce the adhesiveness with the mold resin, so that the expanded water generated during heating is released and the mold resin A means for preventing the occurrence of cracks has been disclosed (Japanese Patent Laid-Open No. 60-
208846).

[0005]

However, in the above-mentioned prior art, since the surface portion of the island support of the plastic IC is processed so as to reduce the adhesiveness with the mold resin, the adhesiveness with the mold resin is reduced. However, due to its low performance, there is a problem that when it is used for a long period of time, due to temperature cycling, etc., a gap occurs between the mold resin and the lead and moisture enters, and no definitive solution has been found. .

An object of the present invention is to provide a technique capable of improving the moisture resistance of the package of the resin-sealed semiconductor device.

The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

[0008]

The outline of the representative one of the inventions disclosed in the present application will be briefly described as follows.

In a resin-sealed semiconductor device in which a semiconductor chip is mounted on a tab, the lead and the semiconductor chip are electrically connected and sealed with a mold resin, the tab and the tab suspension lead are different from the lead. Composed of materials.

[0010]

According to the above-mentioned means, when the resin-sealed semiconductor device is surface-mounted on the substrate, the water vapor generated at the interface between the tab and the mold resin by the moisture absorbed by the mold resin is transmitted through the tab suspension lead to the outside. As the moisture absorbed by the mold resin evaporates, the stress acting on the interface between the mold resin and the semiconductor chip is relieved, and the mold resin cracks or between the mold resin and the semiconductor chip surface, or between the mold resin and the leads. It is possible to reduce the deterioration of the adhesiveness. As a result, the occurrence of mold resin cracks can be prevented.

[0011]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a plan view showing a lead frame structure of a small outline package which is an embodiment of the present invention, and FIG. 2 shows a schematic structure of an embodiment of a resin-sealed semiconductor device of the present invention. It is sectional drawing shown.

The resin-sealed semiconductor device of this embodiment is shown in FIG.
As shown in, mounting the semiconductor chip 2 on the tab 1,
The lead 3 and the semiconductor chip 2 are electrically connected by a bonding wire 4 and sealed with a molding resin 5.

In the lead frame of this embodiment, as shown in FIG. 1, the material of the lead 3A is different from the material of the tab 1 and the tab suspension lead 1A. For example,
The tab 1 and the tab suspension lead 1A are made of Fe-based 42 alloy (42% Ni.Fe alloy or 50% Ni.Fe alloy), and the lead 3A is made of Cu-based Cu /
2% Sn / 0.2% Ni (2% Sn on Cu, 0.2% Ni on it) is used.

As described above, the tab 1 and the tab suspension lead 1
When Fe-based 42 alloy is used as the material of A, as shown in FIG. 3 (a diagram showing the results of the temperature cycle test), the temperature cycle characteristics (lifetime) of the resin-sealed semiconductor device are shown.
Can be improved. As for the material of the signal leads, Cu-based materials have more stable and better moisture resistance than Fe-based materials, but the mechanism has not been clarified.

As can be seen from the above description, according to this embodiment, the lead 3 is made of a Cu-based material having good adhesion to the mold resin 5, the tab 1 and the tab suspension lead 1A.
Since a Fe-based material, which has a weaker adhesiveness than the Cu-based material, is used as the material of, the tab 1 and the mold resin 5 such as resin are mounted at the time of mounting as compared with the structure composed of only the Cu-based material. The water vapor generated at the interface easily reaches the outside through the tab suspension lead 1A. Due to this effect, the stress acting on the interface between the mold resin 5 and the semiconductor chip 2 is relieved as the moisture absorbed by the mold resin 5 is vaporized at the time of mounting, and the reliability against the mold resin crack and the adhesion deterioration is at present. A tab 1, a tab suspension lead 1A and a lead 3 which are made of only a Cu-based material which is said to have good moisture resistance.
Can be further enhanced than the package structure using (see FIG. 3).

Although the present invention has been specifically described based on the embodiments, it is needless to say that the present invention is not limited to the embodiments and various modifications can be made without departing from the scope of the invention. ..

[0018]

The effects obtained by the typical ones of the inventions disclosed in the present application will be briefly described as follows.

When the resin-encapsulated semiconductor device is surface-mounted on the substrate, water vapor generated at the interface between the tab and the resin due to moisture absorbed by the mold resin is discharged to the outside through the tab suspension leads. The stress acting on the interface between the mold resin and the semiconductor chip is relieved as the absorbed moisture evaporates, and the crack of the mold resin and the deterioration of the adhesion between the mold resin and the surface of the semiconductor chip and between the mold resin and the leads are reduced. be able to. As a result, the occurrence of mold resin cracks can be prevented, and the reliability of the resin-sealed semiconductor device can be improved.

[Brief description of drawings]

FIG. 1 is a perspective view of a small type according to an embodiment of the present invention.
A plan view showing the lead frame structure of the outline package,

FIG. 2 is a sectional view showing a schematic configuration of an embodiment of a resin-sealed semiconductor device of the present invention,

FIG. 3 is a diagram showing a result of a temperature cycle test of this example.

[Explanation of symbols]

1 ... tab, 1A ... tab suspension lead, 2 ... semiconductor chip,
3 ... Lead, 4 ... Bonding wire, 5 ... Mold resin.

Claims (1)

[Claims] 1. A resin-sealed semiconductor device in which a semiconductor chip is mounted on a tab, the lead and the semiconductor chip are electrically connected to each other, and the semiconductor chip is sealed with a mold resin. A resin-encapsulated semiconductor device, characterized in that is composed of different materials.