JPH0629432A - Semiconductor device - Google Patents

Abstract

PURPOSE:To reduce thermal resistance by improving dissipation performance of a semiconductor device mounting a high-power driving semiconductor element, and to prevent deformation of an outer lead which is caused by a larger-size heat sink, and further to prevent it from becoming a larger-scale system in which the semiconductor device is mounted. CONSTITUTION:The surface forming the circuit of a semiconductor 1 is fixed on a Cu-W block 13 provided in the central part of a metal cap 6 through a polyimide film 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device which requires high power driving, and more particularly to the structure of a semiconductor device having a large heat sink.

[0002]

2. Description of the Related Art Conventionally, the structure of a semiconductor device having this type of heat sink has been constructed as shown in FIG. That is, in FIG. 3, reference numeral 1 denotes a semiconductor element made of silicon.
The semiconductor element 1 and the ceramic substrate 3 are electrically connected by an Al wire 4. Also,
Reference numeral 6 denotes a metal cap, which is fixed to a metal seal ring 5 provided on the ceramic base 3 by a seam weld method or the like to hermetically seal the ceramic base 3.

Reference numeral 7 denotes an external lead provided on the ceramic substrate 3 for taking out an external electrode. Reference numeral 19 denotes a metal heat dissipation plate made of aluminum or the like, which is fixed to the ceramic base 3 with a silicone resin 8.

At this time, after the semiconductor device is mounted on a predetermined mounting board, the heat generated in the semiconductor element 1 in the energized state is dissipated from the heat dissipation plate 19 through the ceramic base body 3, and especially the heat dissipation plate is forcibly forced to the heat dissipation plate. The heat radiation effect is improved by applying wind.

[0005]

However, the above-described semiconductor device having the conventional heat sink has the following drawbacks.

That is, in recent years, particularly in a semiconductor device having a semiconductor element such as a high-performance ECL gate array mounted thereon, the ceramic substrate 3 has to be miniaturized as much as possible in order to improve the electrical characteristics, while at the same time, high In order to maximize the heat dissipation function from the necessity of power drive, the heat dissipation plate 1
The size of 9 is inevitable. In this case, there is a drawback that the external lead 7 is easily deformed by the weight of the metal heat dissipation plate 19 in a packaging process or a transportation process of handling the semiconductor device after the heat dissipation plate 19 is fixed.

Further, when a semiconductor element which requires high power driving such that power consumption exceeds several tens of watts is mounted, the size of the heat dissipation plate 19 becomes higher than 10 cm. There has been a drawback in that the mounting board spacing of a set such as a computer in which a semiconductor device is mounted becomes large, and accordingly, it is difficult to realize the miniaturization of the system.

The present invention has been made in view of the above-mentioned conventional circumstances, and therefore, an object of the present invention is to provide a novel semiconductor device capable of solving the above-mentioned drawbacks inherent in the conventional technique. It is in.

[0009]

In order to achieve the above object, a semiconductor device according to the present invention has a heat dissipation plate fixed to a ceramic substrate on which a semiconductor element is mounted, and a circuit forming surface of the semiconductor element. Is fixed to the protruding portion on the inner wall of the metal cap via the insulating film. As a result, the heat generated in the semiconductor element when the semiconductor device is energized can be dissipated from both the heat dissipation plate and the metal cap.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will now be specifically described with reference to the drawings for each of its preferred embodiments.

FIG. 1 is a sectional view showing a first embodiment according to the present invention.

In FIG. 1, reference numeral 1 is a semiconductor element made of silicon, 2 is a ceramic substrate to which the semiconductor element 1 is fixed via an Au-Si brazing material 2, and 4 is a semiconductor element 1 and a ceramic substrate 3. 5A and 5B respectively show the Al wires that are electrically connected to each other, and 5 is a seal ring made of Kovar or the like fixed to the ceramic base 3, and the metal cap 6 is fixed by the seam weld method or the like to hermetically seal the ceramic base 3. Reference numeral 7 is an external lead for taking out an external electrode fixed to the ceramic base 3, 9 is a metal heat dissipation plate made of aluminum or the like, and fixed to the ceramic base 3 by a silicone resin 8 having a good thermal conductivity.

Reference numeral 11 is a polyimide film, and this polyimide film 11 is fixed on the circuit formation surface of the semiconductor element 1 through an insulating silicone resin 10.
The surface opposite to the semiconductor element 1 is fixed to a Cu-W block 13 having a good thermal conductivity incorporated in the central portion of the metal cap 6 with a silicone resin 12 interposed therebetween.

With this structure, the heat generated in the semiconductor element 1 in the energized state of the semiconductor device is radiated from the back surface of the semiconductor element 1 through the ceramic substrate 3 and the metal heat radiating plate 9, and the circuit of the semiconductor element 1 is formed. Heat is also radiated from the surface side through the Cu-W block 13 provided in the center of the metal cap 6.

For this reason, in the conventional semiconductor device in which a heat dissipating plate made of Al and having a height of about 3 cm is attached to a ceramic substrate of about 40 mm □, the thermal resistance (ΘJa) is 5 to 10 ° C / W (wind speed is 3 m / sec. Or lower). However, in the case of the present embodiment, there is an advantage that the thermal resistance (ΘJa) is reduced by about 20 to 30%.

Based on this, it is not necessary to increase the size of the metal heat sink 9 even when a high power driven semiconductor element is mounted. Therefore, the weight of the metal heat sink 9 causes the external lead in the packaging process and the transportation process of the semiconductor device. 7 has the advantage that it can be prevented from deforming.

Further, there is an advantage that the distance between the substrates of a computer or the like on which the semiconductor device is mounted can be narrowed.

FIG. 2 is a sectional view showing a second embodiment according to the present invention.

Referring to FIG. 2, the second embodiment according to the present invention is a Cu-W provided at the center of the metal cap 6.
The block 13 and the metal radiating plate 9 provided on the ceramic base 3 are connected by a metal piece 16 fixed via silicone resins 14 and 15.

The metal piece 16 can be provided by utilizing an empty portion of an external lead (not shown) fixed to the ceramic base 3. For example, the external lead is fixed only in two directions. In the case of a ceramic substrate called SOP, the metal piece 1
6 may be arranged.

Further, in the case of a ceramic substrate called QFP in which external leads are fixed in four directions, the corner portion of the ceramic substrate 3 or a portion having no external lead which is an electrically non-connect pin is used. The metal piece 16 may be arranged.

According to this structure, the heat generated in the semiconductor element 1 is radiated from the Cu-W block 13 and the metal radiating plate 9 through the metal piece 16, so that the thermal resistance of the semiconductor device is further reduced. It has a great effect, especially when forced air cooling is carried out.

[0023]

As described above, according to the present invention,
Since the circuit forming surface of the semiconductor element is fixed to the protruding portion of the inner wall of the metal cap through the polyimide film,
The heat generated during operation of the semiconductor element is also radiated to the outside of the semiconductor device from the circuit formation surface side. Therefore, compared to the case where heat is radiated from the metal heat sink through the ceramic substrate only from the back surface of the semiconductor element of the conventional structure, about 20 ~ 30% heat resistance (Θ
The effect that Ja) becomes small can be obtained. Along with this, it is possible to obtain an effect that the metal radiator plate can be made smaller than the conventional one.

[Brief description of drawings]

FIG. 1 is a sectional view showing a first embodiment according to the present invention.

FIG. 2 is a sectional view showing a second embodiment according to the present invention.

FIG. 3 is a cross-sectional view showing a conventional semiconductor device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Semiconductor element 2 ... Au-Si brazing material 3 ... Ceramic base 4 ... Al wire 5 ... Seal ring 6 ... Metal cap 7 ... External lead 8 ... Silicone resin 9 ... Metal heat sink 10 ... Silicone resin 11 ... Polyimide film 12 ... Silicone type resin 13 ... Cu-W block 14 ... Silicone type resin 15 ... Silicone type resin 16 ... Metal piece

Claims (3)

[Claims] 1. A semiconductor device in which a semiconductor element is fixed to a ceramic base and the ceramic base is hermetically sealed by a metal cap, and a heat dissipation plate is fixed to the ceramic base and a circuit forming surface of the semiconductor element is provided. A semiconductor device characterized in that a protrusion provided on the inner wall of the metal cap is fixed to the inner wall of the metal cap via an insulating film. 2. The method according to claim 2, wherein the protruding portion provided on the inner wall of the metal cap is made of a metal block having a good thermal conductivity, which is fixed to the central portion of the main substrate of the metal cap. 1. The semiconductor device according to 1. 3. The semiconductor device according to claim 1, further comprising: a metal plate connecting the heat dissipation plate fixed to the ceramic base and the metal cap.