JPS624330A - Semiconductor device - Google Patents

Abstract

PURPOSE:To facilitate leading-out of a control electrode accurately by a method wherein an annular insulation plate is provided at the circumference part adjoining the part, which is contacted with an element, of a nearly annular electrode for leading out the control electrode and an insulating insertion plate is inserted above the electrode. CONSTITUTION:A nearly annular electrode 13a for leading-out is provided to connect the control electrode of a semiconductor substrate 1 to an external electrode 12. An annular insulation plate 13b is provided at the circumference part adjoining the part or the electrode 13a which is contacted with the substrate. An insulating insertion plate 19 is inserted above the electrode 13a. The contact part 13d is pressed against the control electrode of the substrate 1. With this constitution, the control electrode can be lead out easily and accurately.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an improvement in a control electrode extraction structure in a semiconductor device having an annular control electrode.

[Conventional technology]

In large-capacity gate turn-off thyristors and transistors, as the capacity increases, the current flowing through the control electrode (gate or base) increases, and recently, devices that flow a current of several tens of amperes to several tens of OA have been put into practical use. . Particularly in large-capacity gate turn-off circuits, the gate reverse current required during turn-off is large, and the current must flow instantaneously and uniformly, so efforts are made to minimize the impedance between the gate and cathode. For example, the shape of the lead-out portion of the gate electrode is annular in order to shorten the distance from the lead-out portion to the emitter region and to make the current distribution uniform and light.

FIG. 3 shows a first example of a conventional semiconductor device, in which 1 is an element, 1a is a silicon wafer, and 1b is a planar pattern of an element of a gate turn-off thyristor having the annular gate electrode structure. A reinforcing plate supporting the silicon wafer 1a, IC is a gate electrode, 1d is a cathode electrode, and le and If are current collecting electrode portions of the gate.

In addition, as a method of supplying a large current to the gate by lowering the electric resistance of the gate wiring part, there is a conventional method of bringing the gate extraction electrode into pressure contact with the element. It is very effective when used for structural silicon risks and large capacity transistors.

FIG. 4 shows a second example of a conventional semiconductor device, and is a cross-sectional structural diagram of a SIRISK having a structure in which a gate extraction electrode is brought into pressure contact with an element. In the figure, 1 is a thyrisk element, 2 is an insertion plate, 3 is an external cathode electrode, and 4
5 is an insulating support member for positioning the gate take-out lead 4 and the insertion plate 2 with respect to the external cathode electrode 3; 6 is an insulating support member 5 for connecting the tip 4a of the gate take-out lead 4; 7 is a protective tube for insulating the gate lead 4 from the external cathode electrode 3; 8 is an external anode electrode; 9 is a ceramic supporting the SIRIS element 1; 10 is a flange for firmly supporting the external cathode electrode 3 on the ceramic cylinder 9; 11 is an anode flange for firmly supporting the external anode electrode 8 on the ceramic cylinder 9; and 12 is an external gate electrode.

[Problem that the invention seeks to solve]

In this second example of the conventional SIRISK, a highly conductive material such as silver is used for the gate lead-out electrode, which is advantageous in supplying a large current, but the insulating support member is made of alumina sintered body or the like. As a result, the dimensional accuracy is poor, and the clearance between the external cathode electrode 3 and the insulating support member 5 and the clearance between the insulating support member 5 and the gate lead 4 have to be increased. As a result, this conventional gate extraction structure sometimes has insufficient accuracy for use in a gate turn-off thyristor that requires highly accurate positioning.

Further, in the case of a gate turn-off thyristor having an annular gate structure, in order to adopt the structure according to the second example, the tip portion 4a that contacts the element 1 of the gate lead 4
It is necessary to make the annular part into an annular shape, but a pressure contact type gate structure that allows easy and highly accurate positioning of this annular part has not been put into practical use.

The present invention has been made in order to eliminate the drawbacks of the conventional gate extraction structure, and provides a semiconductor device in which the control electrode can be extracted easily and precisely at a predetermined position, and the reliability can be improved. The purpose is to

[Means for solving problems]

A semiconductor device according to the present invention is provided with a substantially annular control electrode lead-out electrode for connecting a control electrode of a semiconductor substrate with an external control electrode, and a ring-shaped control electrode lead-out electrode is provided in a peripheral portion adjacent to a portion of the control electrode lead-out electrode that contacts an element. An insulating board is installed,
Furthermore, an insulating insertion plate is inserted into the upper surface of the extraction electrode main body, and the contact portion is brought into pressure contact with the control electrode.

[Effect]

In this invention, a substantially annular control electrode lead-out electrode is provided for connecting the control electrode of the semiconductor substrate with an external control electrode, and a ring-shaped insulating plate is provided in the peripheral area adjacent to the portion of the control electrode lead-out electrode that contacts the element. is provided, and an insulating insertion plate is further inserted into the upper surface of the extraction electrode body, so that the contact portion is brought into pressure contact with the control electrode.
The control electrode can be easily and precisely taken out at a predetermined position.

(Example〕 Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows the structure of a large-capacity gate turn-off thyristor according to an embodiment of the present invention. In the figure, numeral 1 is a thyristor element which is a semiconductor substrate. A cathode electrode as a main electrode and a gate electrode as a control electrode are formed, and an anode electrode as a second main electrode is formed on the second main surface (lower surface in the drawing). 14 is an outer insertion plate inserted between the outer circumference of the cathode electrode of the element 1 and the outer cathode electrode 18 which is the first outer main electrode, and 15 is an inner part of the cathode electrode of the element 1 and the outer cathode electrode 18. This is the inner insertion plate inserted between the An annular holding groove 18a is recessed in the first main surface side of the external cathode electrode 18, and an annular gate extraction electrode 13 is inserted into the holding groove 18a so as to be vertically movable. This and retaining groove 18
It is urged downward in the figure by a spring 16 inserted between it and the bottom surface of the gate a, and is pressed into contact with the gate electrode of the elm plate 1-1. Reference numeral 19 denotes an annular insulating insertion plate made of alumina or boron nitride for insulating the extraction electrode and the external cathode electrode 18.

FIG. 2 is a sectional view showing the structure of the gate lead-out electrode. In the figure, 13a is a ring-shaped metal part which is the main body of the gate lead-out electrode 13, 13d is a contact part with the element l protruding along the entire lower surface of the ring-shaped metal part 13a, and 13C is a ring-shaped metal part 13a. The wire portion 13b, which is a control lead portion, is brazed to the brazed portion 13e and is an annular insulating plate brazed to the brazed portion 13f around the contact portion.

Next, a method of manufacturing the gate lead-out electrode 13 will be explained.

(1) First, the annular metal part 13a is formed by cutting with the desired precision, and the surface is coated with silver to a thickness of 5 to 10 μm.
However, after that, the plating interface is annealed in hydrogen for 30 to 60 minutes.

(2) Next, the wire portion 13C is brazed to the brazed portion 13e of the annealed annular metal portion 13a, and then the annular insulating plate 13b made of alumina or boron nitride
By brazing the annular metal portion 13a around the contact portion with the element at the brazing portion 13f, the desired gate lead-out electrode 13 is obtained. Here, the material of the wire portion 13c is pure 11 (99.99%), and brazing is performed in hydrogen using silver-copper solder.

Next, the effects will be explained.

In the gate turn-off scissor of this embodiment, the cross-sectional area of the annular metal part 13a is large, so the electrical resistance of the annular metal part 13a is extremely small, and the wire diameter of the wire part 13C is also sufficiently large, so the gate extraction voltage is The potential drop in the trench 13 can be made extremely small, and therefore the uniformity of current distribution can be improved, and as a result, the switching power of the gate turn-off thyristor can be improved. Furthermore, since the outer and inner insertion plates 14 and 15 are positioned by the outer and inner wall surfaces of the insulating plate 13b of the gate extraction electrode 13, respectively, the assembly workability is extremely high. Further, the gate lead-out electrode body 13a is insulated from the external cathode electrode 18 by an annular insulating plate 13b and an annular insulating insertion plate 19.

In addition, the gate extraction electrode 13 of this embodiment has the functions of both the insulating support member and the gate extraction wire in the conventional gate press-contact structure, so there is no need for the conventional work of engaging these. In addition to improving workability, in this embodiment, the positioning accuracy of the extraction electrode 13 is controlled by the annular metal part 13a and the annular insulating plate 13b, which have high dimensional accuracy, so the positioning accuracy, which was a problem in the past, is also improved. Become.

In the above embodiment, the gate turn-off thyristor was described, but the present invention can also be applied to large-capacity semiconductor devices having annular control electrodes, such as high-power transistors and gate-assisted turn-off thyristors, and similar effects can be obtained. can bring. Further, the present invention can be applied not only to a structure for taking out an annular control electrode, but also to a gate taking-out electrode of a conventional center gate structure, and in this way, workability and positioning accuracy can be improved.

[Effects of the Invention] As described above, according to the semiconductor device of the present invention, a substantially annular control electrode extraction electrode is provided that connects the control electrode of the semiconductor substrate to an external control electrode, and the control electrode extraction electrode is in contact with an element of the control electrode extraction electrode. An annular insulating plate is provided on the periphery adjacent to the area where the gate is connected, and an insulating inserting plate is inserted into the upper surface of the extraction electrode body so that the contact area is brought into pressure contact with the control electrode. This has the effect of providing a gate extraction structure with extremely high precision, high reliability, and good workability for the base body.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a semiconductor device (gate turn-off thyristor) according to an embodiment of the present invention, FIG. 2 is a sectional view showing the structure of the gate lead-out electrode of the above embodiment, and FIG. 3 is a sectional view of a conventional annular gate structure. FIG. 4 is a plan view showing a cathode/gate pattern of a gate turn-off thyristor having a gate turn-off type, and FIG. 4 is a sectional view showing the structure of a conventional center gate pressurizing type thyristor. 12... External control electrode, 13... Control electrode take-out electrode, 13a... Take-out electrode body (ring-shaped metal part),
13b... Annular insulating plate, 13c... Control lead part,
13d...Contact part, 16...Spring, 19...
- Annular insulating insertion plate, 1... semiconductor substrate (element). Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (8)

[Claims] (1) A semiconductor substrate having first and second main electrodes on its first and second main surfaces and a control electrode on its first main surface, and electrically connected to the first and second main electrodes of the semiconductor substrate. first and second external main electrodes connected to each other and arranged on the first and second main surfaces; an external control electrode to be connected to the control electrode of the semiconductor substrate; In a semiconductor device, the control electrode lead-out electrode has a substantially annular lead-out electrode main body having a contact portion on its lower surface and an annular insulating plate around the contact portion; A control lead part connected to an external control electrode is provided, and an annular insulating insertion plate is provided on the upper surface of the lead-out electrode body, and the lead-out electrode body connects to the control electrode of the semiconductor substrate at its contact part. A semiconductor device characterized by being pressure-welded. (2) Pressure contact of the extraction electrode body to the control electrode is achieved by a spring inserted together with the extraction electrode body into an annular holding groove recessed in the first external main electrode. A semiconductor device according to claim 1. (3) The semiconductor device according to claim 1 or 2, wherein the contact portion is annular along the entire circumference of the extraction electrode main body. (4) The semiconductor device according to claim 1 or 2, wherein the contact portion comprises a plurality of arcuate portions arranged along the entire circumference of the extraction electrode main body. (5) The semiconductor device according to any one of claims 1 to 4, wherein the surface of the contact portion is plated with silver or gold. (6) The semiconductor according to any one of claims 1 to 5, wherein the control electrode extraction electrode is formed using a good electrical conductor whose main component is copper or aluminum. Device. (7) The insulating insert plate is made of a sintered product of an insulating material whose main component is aluminum oxide or boron nitride. A semiconductor device according to claim 1. (8) The semiconductor device according to any one of claims 1 to 7, wherein the annular insulating plate of the extraction electrode body is fixed to the extraction electrode body by brazing. .