JPH06104349A - Semiconductor device - Google Patents

Abstract

PURPOSE:To prevent occurrence of insufficient wire bonding in a semiconductor device having such a structure that a semiconductor pellet is brazed to an upper surface of a nonmetallic heat sink with an Au-metallized layer in between. CONSTITUTION:After an Au-metallized layer 2 is formed on a nonmetallic heat sink 7 and Au-plated leads 1 are joined to the layer 2, a semiconductor pellet 4 is joined to the upper surface of the layer 2 by using a brazing material 6 and, at the same time, a buffer zone 8 is formed between the pellet 4 and leads 1 so as to inhibit the flowing out of the brazing material 6. Therefore, the creeping up of the material 6 used for joining the pellet 4 to the layer 2 to the bonding areas of the leads 1 can be surely prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device, and more particularly to a technique effective when applied to a semiconductor device having a structure in which a semiconductor pellet is brazed and bonded onto a non-metal heat sink via a gold metallization layer. For example, the present invention relates to a technique effectively applied to a GaAs transistor forming a transmission final portion of a mobile communication device.

[0002]

2. Description of the Related Art For example, as shown in FIG. 2, a GaAs transistor used in a transmission final portion of a mobile communication device is provided on a non-metal heat sink 7 made of aluminum nitride having excellent heat transfer characteristics and electrical insulation characteristics. After the gold metallization layer 2 is formed and the gold-plated leads 1 are bonded onto the metallization layer 2, the semiconductor pellets 4 are brazed onto the metallization layer 2 using a gold brazing material (Au-Ge, Au-Sn) 6. A bonding wire 5 for taking out an electrode is provided between the lead 1 and the semiconductor pellet 4 while being bonded (for example, "Nikkei Electronics", Nikkei Electronics, July 1, 1985 (n.
o. 372) "p. 295: new product).

[0003]

However, the present inventors have clarified that the above-mentioned technique has the following problems.

That is, as shown in FIG. 4, in the conventional semiconductor device, a brazing material 6 for brazing the semiconductor pellet 4 onto the gold metallization layer 2 flows out to the periphery and expands to bond on the adjacent lead 1. Crawling up to the area causes a problem of defective wire bonding.

An object of the present invention is to provide a technique of preventing wire bonding failure in a semiconductor device having a structure in which a semiconductor pellet is brazed and bonded onto a non-metal heat sink via a gold metallization layer.

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

[0007]

Among the inventions disclosed in the present application, a brief description will be given to the outline of typical ones.
It is as follows.

That is, a gold metallization layer is formed on a non-metal heat sink, gold plating leads are bonded onto this metallization layer, and then a semiconductor pellet is bonded onto the metallization layer using a brazing material. A buffer zone is provided between the leads to prevent the brazing material from flowing out.

[0009]

According to the above means, it is possible to reliably prevent the brazing material for joining the semiconductor pellets from climbing up to the bonding area of the lead.

Thus, the object of preventing wire bonding failure in a semiconductor device having a structure in which a semiconductor pellet is brazed and bonded onto a non-metal heat sink via a gold metallized layer is achieved.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the drawings.

In the figures, the same reference numerals indicate the same or corresponding parts.

FIG. 1 shows an embodiment of a semiconductor device to which the technique of the present invention is applied. Reference numeral 1 is a heat sink suspension lead whose surface is plated with gold, 2 is a gold metallized layer, and 3 is a lead. Frame, 4 is a semiconductor pellet on which a GaAs transistor is formed, 5 is a bonding wire, 6 is a brazing filler metal for pellet bonding having a composition such as Au-Ge or Au-Sn, 7 is a non-metal heat sink made of aluminum nitride, 8 Is a gap serving as a buffer zone for preventing the brazing material 6 from flowing out and expanding.

In the semiconductor device described above, first, the gold metallized layer 2 is formed on the surface of the heat sink 7 made of aluminum nitride. On top of this gold metallization layer 2 is shown in FIG.
The lead 1 connected to the lead frame 3 as shown in FIG. Subsequently, the semiconductor pellet 4 made of a GaAs semiconductor substrate is brazed and joined by the brazing material 6.
After that, the lead 1 and the semiconductor pellet 4 are electrically connected by the bonding of the wire 5.

Finally, resin molding is performed to obtain a finished product.

Here, when the semiconductor pellet 4 is brazed and joined to the gold metallized layer 2, the brazing material 6 melted for this joining flows out around the semiconductor pellet 4 and expands to reach the adjacent lead 1. Further, the lead 1 is climbed up and spreads to the bonding area.

However, at this time, since the gap 8 is interposed in the gold metallized layer 2 between the semiconductor pellet 4 and the lead 1 as a buffer zone, the expansion of the flow of the brazing material 6 is increased by the surface tension. You will be blocked at.

As a result, the brazing material 6 for joining the semiconductor pellets 4 is surely prevented from climbing up to the bonding area on the lead 1 and the defective wire bonding is prevented.

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

For example, the brazing material 6 may be solder or the like other than gold alloy.

In the above description, Ga, which is the field of application of the invention made by the present inventor, was the background.
The case where the invention is applied to the As semiconductor device has been described, but the invention is not limited thereto, and the invention can be applied to, for example, a silicon semiconductor device.

[0022]

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

That is, it is possible to prevent wire bonding defects in a semiconductor device having a structure in which a semiconductor pellet is brazed and bonded onto a non-metal heat sink via a gold metallization layer.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part of a semiconductor device to which the technique of the present invention is applied.

FIG. 2 is a sectional view of a main part of a conventional semiconductor device.

FIG. 3 is a plan view of a semiconductor device according to the present invention.

FIG. 4 is a sectional view taken along line AA in FIG.

5 is a partially enlarged view of portion B in FIG.

FIG. 6 is a view showing a shape example of a lead frame in which leads are connected.

[Explanation of symbols]

 1 Heat Sink Suspended Lead 2 Gold Metallization Layer 3 Lead Frame 4 Semiconductor Pellet 5 Bonding Wire 6 Brazing Material 7 Non-metallic Heat Sink Made of Aluminum Nitride 8 Gap as a Buffer Zone

Claims (1)

[Claims] 1. A gold-plated lead is bonded to a gold metallized layer formed on a non-metal heat sink, and a semiconductor pellet is bonded to the metallized layer using a brazing material, and an electrode is provided between the lead and the semiconductor pellet. What is claimed is: 1. A semiconductor device in which a bonding wire for taking out is passed, wherein a buffer band for preventing the brazing material from flowing out and expanding is interposed between the semiconductor pellet and the lead.