JPH0543474Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention provides island-shaped cathode electrodes separated from each other as first electrodes on one main surface of a semiconductor pellet such as a thyristor. It has a gate electrode as a second electrode provided so as to surround the cathode electrode, and particularly relates to the structure for leading out the external lead.

[Prior Art] FIGS. 1A and 1B are structural diagrams of a gate turn-off thyristor (hereinafter referred to as GTO) having a PNPN four-layer structure. As shown in the figure, in this GTO, a semiconductor pellet 2 having a PNPN structure is fixed on a temperature compensating plate 1.
On the upper surface), island-shaped cathode electrodes 3 separated from each other and a gate electrode 4 are provided so as to surround the cathode electrodes 3. Further, the temperature compensating plate 1 is fixed to one main surface (lower surface in the drawing), and constitutes an anode electrode 5.

From the cathode electrode 3, gate electrode 4 and anode electrode 5, external leads 6,
7 and 8 are insulated from each other and pulled out to the outside by a pressure contact structure (not shown).

Conventionally, the following method has been employed to lead out the external lead 7 from the gate electrode 4.

That is, a conductor (not shown) which will become the external lead 7 is pressed into contact with the gate electrode 4 in the center of the semiconductor pellet 2, and the island-shaped cathode electrode 3 is
As shown in FIG. 1A, thin metal wires 9 are connected to the gate electrode 4 on the outer periphery surrounding the area by bonding or the like at multiple locations, and a part of the thin metal wires 9 is electrically connected to the conductor in the central portion. I am trying to connect it to the outside and take it out.

[Problems to be Solved by the Invention] However, in the above-mentioned conventional structure, since the external lead 7 drawn out from the gate electrode 4 on the outer periphery surrounding the cathode electrode 3 is connected by bonding or the like with a thin metal wire 9, Connections are unreliable. In particular, in GTO, when a reverse bias voltage is applied between the gate and the cathode during turn-off, a current of several tens of amperes flows through the thin metal wire, so the wire diameter of this thin wire 9 must be increased, and , the bonding process had to be done with great care. In addition, when connecting by bonding etc. the thin metal wire 9, as shown in FIG.
As shown in the figure, since the gate is connected in spots around the gate region, the gate current does not flow uniformly during turn-on and turn-off, making it impossible to increase the controllable anode current (I _TGQ ) of the GTO. I have a task to do.

[Purpose of the invention] The present invention has been made to solve the above-mentioned problems, and provides a pressure contact type semiconductor device having a structure in which an external lead is drawn out from a gate electrode on the outer periphery of a semiconductor pellet. To provide a pressure contact type semiconductor device that can ensure reliability of connection of external leads, improve workability during assembly, and increase controllable anode current in the case of GTO. With the goal.

[Means for Solving the Problems] A pressurized contact type semiconductor device of the present invention includes a first electrode in the form of an island separated from each other on one main surface of a semiconductor pellet, and a first electrode provided so as to surround the first electrode. In a pressure contact type semiconductor device having a structure in which an external lead is drawn out from the second electrode, the conductor is in pressure contact with the second electrode at the center of the semiconductor pellet; A conductive ring that presses into contact with the second electrode on the outer periphery of the semiconductor pellet, and a conductive ring that extends approximately at the center in the diametrical direction between the conductor and the conductive ring, and the conductor and the conductive ring are electrically connected. It is equipped with an external lead that is connected to the external lead.

[Function] Since the pressure contact type semiconductor device of the present invention is constructed as described above, the external lead can be drawn out from the outer periphery of the semiconductor pellet without using a thin metal wire, that is, without the need for wire bonding or the like. As a result, peeling from the connection portion, accidents such as cutting of the thin metal wire, etc. are prevented, and the reliability of this type of device and workability during assembly are improved. Furthermore, since a small-diameter thin metal wire is not used, a large current can be passed through the gate. Furthermore, since the conductor and the conductive ring contact the entire gate electrode,
The gate current can be made uniform and the controllable anode current of the GTO can be increased.

[Embodiment] FIG. 2 is a longitudinal sectional view showing an embodiment of the pressure contact type semiconductor device of the present invention.

In the figure, a cathode electrode and a gate electrode, which are insulated and separated from each other, are formed on one main surface of a semiconductor pellet 11 which has been formed in advance into a four-layer structure. The cathode electrode is formed, for example, as a plurality of small islands surrounding the gate electrode in the center of the semiconductor pellet 11 and extending radially in the direction of its outer circumference, and the gate electrode is also formed on the outer circumference of the small island. ing.

From the above cathode electrode and gate electrode,
The respective external leads are pulled out. That is, a cathode electrode plate 12 with a hollowed out center portion is mounted on the cathode electrode, and the electrode plate 12 and the upper electrode post 14 of the envelope 13 are configured to be in contact with each other. On the other hand, since it is necessary to electrically connect the gate electrode at the center and the gate electrode at the outer periphery, the following configuration is adopted.

That is, an insulating ring 15 having an inner diameter large enough to insert the cathode electrode plate 12 and the tips of the upper electrode posts 14 is prepared. Then, a conductive ring 16 is attached to the outer periphery of this insulating ring 15. The lower end surface of the conductive ring 16 is configured to be in total contact with the gate electrode on the outer periphery of the semiconductor pellet 11.

On the other hand, a conductor 17 is in contact with a gate electrode provided at the center of the semiconductor pellet 11, and this conductor 17 is housed within an insulating ring 18.

The conductive ring 16 that contacts the gate electrode at the outer periphery and the conductor 17 that contacts the gate electrode at the center are led out by a common external lead 19, and their configuration is shown in FIGS. Third
This will be explained with reference to the figures.

That is, common recesses 15 are provided in the diametrical direction of the insulating ring 15 and the conductive ring 16, and in the diametrical direction of the conductor 17 and the insulating ring 18, respectively.
a, 16a, 17a, 18a are provided, and this recess 1
5a, 16a, 17a, and 18a are inserted with external lead-out leads 19 extending in the diametrical direction thereof, and the conductor 17 and conductive ring 16 are fixed by soldering. As a means for pressurizing the conductor 17 and the conductive ring 16, an insulating disc 20 and a metal disc 21 are provided on the conductor 17 in the central part, and the metal disc 21 and the upper electrode post 14 are provided on the conductor 17.
A disc spring 23 is inserted between the conductor 17 and the inner bottom surface of a recess 22 (see FIG. 2) to press the conductor 17 toward the gate electrode. On the other hand, in the outer peripheral part, the flange part of the metal washer 25 and the upper electrode post 14 is applied so that a pressing force is applied via the insulating washer 24 and the metal washer 25 provided on the insulating ring 15 and the conductive ring 16. A disc spring 26 is provided between the two.

In this way, the entire gate electrode is led out from the gate electrode at the center and the gate electrode at the outer periphery of the semiconductor pellet 11 by one common external lead 19.

Note that a temperature compensating plate 27 is provided on the lower surface of the semiconductor pellet 11, and this temperature compensating plate 27 contacts the anode electrode post 28.
8 is connected to one end of the ceramic ring 29,
It constitutes an envelope 13.

Further, inside the envelope 13, a semiconductor pellet 11 is placed.
In order to position the conductive ring 16 and the like, a positioning insulating ring 30 is inserted.

[Effects of the invention] As described above, the present invention connects the gate electrode, especially the gate electrode provided on the outer periphery of the semiconductor pellet, to the gate electrode on the outer periphery surface of the semiconductor pellet, instead of spot-connecting it by bonding thin metal wires as in the past. A conductive ring that contacts the entire semiconductor pellet is provided, and this ring and a conductor that contacts the gate electrode provided in the center of the semiconductor pellet are electrically connected to each other by an external lead and drawn out to the outside. It has the following effects.

(1) The external leads are extended from the outer periphery of the semiconductor pellet without using fine metal wires and without the need for wire bonding, etc., so that peeling off from the connection and accidents such as the cutting of the fine metal wires are prevented, thereby improving the reliability of this type of semiconductor device.

(2) Since no thin metal wire is used, it is possible to pass a large current through the gate.

(3) Work efficiency during assembly is improved because the careful attention required when performing wire bonding is not required.

(4) Rather than spot connections using thin metal wires,
Since it contacts the entire gate electrode on the outer periphery, the gate current flowing from this gate region to the island-shaped cathode emitter region can be made uniform.
The controllable anode current (I _TGQ ) of the GTO can be increased.

(5) The structure is such that the conductor placed in the center and the conductive ring placed on the outer periphery are connected to each other by extending them approximately at the center in the diametrical direction, so that the gate electrode can be connected over the shortest distance. It can be pulled out to the outside.

Although the embodiments of the present invention have been explained using GTO as an example, it goes without saying that the present invention is applicable not only to GTO but also to other semiconductor devices having control electrodes, such as high-power transistors.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a conventional pressure contact type semiconductor device, in which FIG. 1A is a plan view thereof, and FIG.
2 is a vertical sectional view of a pressure contact type semiconductor device showing an embodiment of the present invention, and FIG. 3 is a longitudinal sectional view of the device.
FIG. 3 is a component diagram showing the main parts of the pressure contact type semiconductor device of the present invention. 11... Semiconductor pellet, 16... Conductive ring, 17... Conductor, 19... External lead.

Claims (1)

[Claims for Utility Model Registration] Island-shaped first electrodes separated from each other on one main surface of a semiconductor pellet, and second electrodes at the center and outer periphery of the semiconductor pellet that sandwich and surround the first electrode. A pressure contact type semiconductor device having a structure in which an external lead is drawn out from the second electrode, further comprising an electrode plate in contact with the first electrode on the semiconductor pellet, and a central portion of the electrode plate. Inside the hole,
one end is positioned and inserted through an insulating ring and comes into contact with a second electrode in the center of the semiconductor pellet, and the other end is inserted into a recess of an upper electrode post in pressure contact with the electrode plate, and One end is positioned and in contact with the conductor to which pressure is applied by a disc spring in the recess and the second electrode on the outer periphery of the semiconductor pellet via an insulating ring, and the other end is in contact with the second electrode on the outer periphery of the semiconductor pellet. a conductive ring to which pressure is applied by a disc spring inserted between the end and the outer periphery of the upper electrode post; The body is pressed by a disc spring in the recess, and the conductive ring is pressed by a disc spring inserted into the outer periphery of the upper electrode post, so that the conductor and the conductive ring are electrically connected. A pressurized contact type semiconductor device comprising: external leads that are commonly connected;