JPS6235527A - Semiconductor device - Google Patents

Abstract

PURPOSE:To realize a preferably contacting state due to the prescribed pressure of a gate turn-OFF thyristor element between cathode and anode electrodes by inserting an inserting plate made of the same metal as a reinforcing member and of substantially the same thickness as that between a semiconductor element and the cathode element. CONSTITUTION:A rigid and conductive inserting plate 11 made of the same metal as a reinforcing member and having substantially the same thickness as that is inserted between a cathod electrode 9 and an element 1. The electrode 9 is contacted with the element 1 through the plate 11 by the prescribed pressure. Thus, the plate 11 is contacted with the warped projection side of the element 1 at the initial pressing time and effected by a concentrated load based on the projection. The element 1 is flattened as the contacting under pressure is proceeded, and effected by a dispersive load, and substantially uniformized contacting pressure is always applied to the entire contacting surface of the electrode 9. Thus, there is no possibility that a deformation like a central recess is not formed on the electrode 9.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a semiconductor device, and particularly to a pressure contact type semiconductor device.

[Conventional technology]

Figures 3 to 5 show the general structure of a conventional press-contact type semiconductor device of this type, a gate turn-off thyristor.
Shown in Figures (a) and (b).

FIG. 3 is a schematic cross-sectional view showing how the gate turn-off thyristor is installed and assembled in the previous state. In this figure 3,
The gate turn-off thyristor element 1 consists of a semiconductor substrate 2 in which a pn junction is formed, and a reinforcing body 3 whose anode side is brazed with a solder material 4. A gate electrode 5. It has a cathode electrode 7.

A cathode electrode body 9 is placed on the cathode electrode 7 side of this Niremen 1 through a soft metal plate 8, and an anode electrode body 10 is placed in pressure contact with the semiconductor substrate 2 side. It is.

[Problem that the invention seeks to solve]

However, in the pressure contact type semiconductor device according to the conventional example,
The gate turn-off thyristor element 1 is manufactured by generally well-known means, and the semiconductor body 2 and reinforcement body 3 are in the usual case.

As seen in FIG. 4, due to the difference in thermal expansion coefficient during brazing using the brazing material 4, the semiconductor substrate 2 side is convex, and the reinforcing body 3 is convex.
The sides are distorted and deformed so that they become concave.

When the gate turn-off thyristor element 1 in such a deformed state is mounted in close pressure contact between the cathode electrode body 8 and the anode electrode body 10, at the initial stage of pressure contact, the structure shown in FIG. 5(a) is applied. As shown, on the cathode electrode body S side, the central part of element l is in contact with the anode electrode body IO.
On the other hand, the periphery of the element l is brought into pressure contact unevenly, and the cathode electrode body 9 and the anode electrode body 10 themselves are each made of a relatively soft metal such as Cu (copper). Due to the unbalanced load applied at the beginning of this pressure welding, the cathode electrode body S is deformed by a central concave portion 9+1° and the anode electrode body 10 is deformed by a sagging portion 10a, and in this state, the pressing force is gradually increased, for example, Normal, 85+
*In the case of the m element, with a pressure contact force of about 2 to 4 tons, the element 1 is finally flattened as shown in FIG. .

With the gate turn-off thyristor element 1 mounted between the cathode electrode body 9 and the anode electrode body 10 in this way, the cathode electrode body 8. The deformation of the central concave portion 9a and peripheral sagging portion 10a in the anode electrode body 10 has not yet been recovered, and among these portions 9a and 10a, the contact at the central concave portion 8a in particular has become incomplete, resulting in no current flow. concentration of flow,
This resulted in an increase in thermal resistance and a deterioration in current conduction characteristics.

That is, to be more specific, conventionally, the thickness was 800 mm.
N with a thickness of 3.5t for a semiconductor body 2 of g m.

When the reinforcing body 3 made of (molybdenum) is brazed with An (aluminum), the semiconductor element element l
The warping deformation of the element 1 is about 20IL11 at the navel, and in order to eliminate the warp and flatten the element 1, it is necessary to
A pressure contact force of about 1 to 2 tons is required, and the contact force for this purpose is initially applied as a concentrated load to a specific part, and as the element 1 adapts to this and flexes, it shifts to a distributed load. Therefore, the portions deformed by the initially applied concentrated load, especially the central recessed portion 9a of the cathode electrode body 9, become partially in a state where it is difficult to contact the element 1 even after the pressurized mounting is completed. In the case of a device with an electrode contact structure for many emitters separated into islands, such as a gate turn-off thyristor, the current interruption capability is significantly reduced due to the difference in contact pressure to each emitter. However, there was a problem in that characteristics deteriorated.

Therefore, it is an object of the present invention to provide a cathode electrode body that overcomes these conventional problems.

An object of the present invention is to obtain a press-contact type semiconductor device that realizes a good contact state between anode electrode bodies by applying a predetermined pressing force of a gate turn-off silica element.

[Means for solving problems]

In the semiconductor device according to the present invention, an insertion plate made of the same metal as the reinforcing body and having the same thickness as ζ is inserted between the semiconductor element and the cathode electrode body.

[Function] That is, in the present invention, by inserting the insertion plate between the semiconductor element and the cathode electrode body, it is possible to eliminate deformation in the cathode electrode body when the semiconductor element and the cathode electrode body are brought into contact with each other.

〔Example〕

Hereinafter, one embodiment of a semiconductor device according to the present invention will be described in detail with reference to FIG. 1 and FIGS. 2(a) and 2(b).

FIG. 1 is a schematic cross-sectional view showing how to install and assemble a gate turn-off thyristor to which this embodiment is applied, and FIGS. 2 (a) and (b) show how the gate turn-off thyristor element is installed between the cathode and anode electrodes. FIG. 4 is a cross-sectional explanatory diagram showing states in sequence.

In each figure of these embodiments, the same reference numerals as in each of the figures of the conventional example indicate the same or corresponding parts. During the installation by pressure-and-pressure contact, there is also an insertion plate 11° between the cathode electrode body 9 and the element 1, which is made of the same metal as the brazed reinforcing body 3 and has the same thickness. , insert a rigid and conductive insertion plate 11 that has not yet been warped,
Cathode electrode body 9 to element 1 via this insertion plate 11
The contact is made using a predetermined pressing force.

Therefore, in this embodiment structure, the same effect gate is located between the gate turn-off thyristor element 1 and the cathode electrode body 9 and corresponds to the reinforcement body 3 on the anode electrode body 10 side.
That is, in this case, the insertion plate 11 having the same rigidity is interposed and inserted, and this element 1 is inserted into the cathode electrode body 8. In order to bring the anode electrode bodies 10 into close pressure contact, the insertion plate 11 is brought into contact with the curved convex side of the element 1 to receive a concentrated load based on the convex shape, as described above at the time of initial pressure contact. Then, as the pressure welding progresses, the element 1 flattens and receives a distributed load, and during this time.

An averaged contact pressure is constantly applied to the entire surface of the contact surface of the cathode electrode body 8, and as in the conventional structure, the cathode electrode body 8 is deformed into a central concave portion 3a. Without getting used to it, each emitter in this gate turn-off thyristor is in good contact with the cathode, which can improve its current interruption capability.

In other words, as a specific example, it was experimentally demonstrated that the gate turn-off thyristor, which had a conventional structure with a withstand voltage of 4500 V and a maximum allowable breaking current of 200 OA, could be increased to a maximum allowed breaking current of 3000 A by applying this example structure. I was able to confirm this.

Further, by inserting a metal plate of No (molybdenum), W (tungsten), etc. between the element and the anode side, better results can be obtained than when simply inserting it on the cathode side.

In the above embodiments, the case where the present invention is applied to a gate turn-off thyristor has been described, but it goes without saying that it can also be applied to, for example, a high power transistor having the same structure.

〔Effect of the invention〕

As detailed above, according to the present invention, a semiconductor element is provided in which a reinforcing body is brazed to one surface of a semiconductor substrate and an electrode is formed on the other surface, and the reinforcing body of this semiconductor element is brazed. In a semiconductor device in which an anode electrode body and an element electrode are formed on one side, and a cathode electrode body is pressed onto the other side, at least between the element electrode and the cathode, a reinforcement body of the same material and of the same thickness as the reinforcing body is formed. Since the insertion plate is inserted, the semiconductor element and each electrode body can be properly pressure-connected, which helps improve the characteristics and reliability of this type of semiconductor element, and the structure is simple. It has excellent features such as being easy to implement.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view showing how a gate turn-off thyristor is mounted and assembled to which an embodiment of the semiconductor device according to the present invention is applied, and FIGS. FIG. 3 is a cross-sectional explanatory view sequentially showing the mounting state of the turn-off thyristor element, and FIG. 3 shows the mounting and assembly state of the gate turn-off thyristor in a state before the cathode, anode, and each electrode body are brought into pressure contact according to a conventional example. FIG. 4 is a cross-sectional view showing the element taken out, and FIGS. 5(a) and 5(b) are explanatory cross-sectional views sequentially showing how the element is installed between the cathode and anode electrodes. 1...Kate turn-off silicon element (semiconductor element), 2...Semiconductor substrate, 3...
Reinforcement body, 4... Solder material, 5... Gate electrode, ?・
...Cathode electrode, 8...Soft metal plate, 9...
Cathode electrode body, 10... Anode electrode body, 11... Insertion plate. Agent Masuo Oiwa Figure 1 Figure 3: Guzu Camphor (Figure 2 (Q) Figure 2 (b)

Claims (5)

[Claims] (1) It has a semiconductor body having at least one pn junction, one side of the semiconductor body is brazed with a reinforcing body made of a conductive metal having a similar coefficient of thermal expansion, and the other side is
A semiconductor element is provided with an element electrode made of a highly conductive metal, and an anode electrode body is provided on one side of the semiconductor element to which the reinforcing body is brazed, and a cathode electrode body is provided on the other side on which the element electrode is formed. , in a semiconductor device constructed by press-contacting the element electrode and the cathode electrode body, an insertion plate made of the same metal as the reinforcing body and having substantially the same thickness is interposed between at least the element electrode on the other surface side and the cathode electrode body. A semiconductor device characterized by being inserted. (2) The semiconductor device according to claim 1, wherein copper is used as the material of the anode or cathode electrode body, and molybdenum or tungsten is used as the material of the insertion plate. (3) The semiconductor device according to claim 1 or 2, characterized in that a conductive soft metal plate is inserted between the element electrode and the insertion plate. (4) The semiconductor device according to claim 1, wherein the semiconductor element is a gate turn-off thyristor. (5) The semiconductor device according to claim 1, wherein the semiconductor element is a high power transistor.