JPS6314460Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a structure for fixing a flat thyristor, particularly for preventing planar and rotational movement of a semiconductor substrate.

As shown in Fig. 1, a conventional flat thyristor has an anode electrode which is bonded to a semiconductor substrate 1 of the thyristor structure with low resistance by brazing, and is made of W or Mo, which has a coefficient of thermal expansion close to that of the semiconductor substrate 1. 6. A metal base 3 in sliding contact with the metal base 3, and a cathode electrode 5 bonded with low resistance to the other surface of the semiconductor substrate 1.
and a metal cover 2 in sliding contact with a gate lead wire 4 and a cathode electrode 5. In addition, the ends of the semiconductor substrate 1 are covered with a bonding surface stabilizer 7 in order to reliably obtain the desired withstand voltage, and the entire semiconductor substrate 1 is covered with a seal 8 having high airtightness and insulation, a metal cover 2 and a metal base. It is housed in an airtight container consisting of 3 parts. In this configuration, the contact surface 10 between the metal base 3 and the anode electrode 6 and the contact surface 11 between the metal cover 2 and the cathode electrode 5 are not brazed, and the pressure applied to the metal cover 2 and the metal base 3 causes the anode electrode 6 and the metal In the case of a structure in which the base 3 is brought into low-resistance contact, if a strong external force is applied to the semiconductor substrate 1 in a direction horizontal to the contact surface, the semiconductor substrate 1 will shift laterally. This may cause the contact position to shift due to pressure, resulting in poor contact, or
There is a risk that the reliability of the device will be significantly reduced, such as the gate lead wire 4 being disconnected or, in extreme cases, the edge of the semiconductor substrate being damaged. Therefore, as a method for eliminating these drawbacks, it has been proposed to provide a guide 9 for preventing plane movement, as shown in FIG. This certainly prevents the semiconductor substrate from moving laterally against strong external forces.
However, when actually turning the device on and off,
Many times, the temperature rises in the conducting state and decreases in the non-conducting state. For this reason, the semiconductor substrate 1 repeatedly expands and contracts, albeit very slightly, and there is a concern that the semiconductor substrate 1 may rotate within the plane. In such a case, in a configuration in which the gate lead wire 4 is fixed to the semiconductor substrate 1, if the fixed position is on the side, the gate lead wire 4 may be broken, and if the fixed position is in the center, the gate lead wire 4 may be twisted. arise.

The purpose of the present invention is to eliminate the above-mentioned drawbacks of the prior art, prevent planar movement and rotational movement of the semiconductor substrate,
An object of the present invention is to provide a highly reliable pressure contact flat semiconductor device.

In order to achieve the above-mentioned object, the present invention provides the anode electrode and the metal base with defective portions whose circumferential ends facing each other are non-circular, and a movement preventing body is fitted into both the defective portions.

The structure and effects of the present invention will be explained based on the embodiment shown in FIG.

The difference between this embodiment and the conventional example shown in FIG. 1 is as follows.
A defect 12 is provided in a part of the peripheral edge of the anode electrode 6, and a defect 15 is provided all around the edge of the metal base 3, and a portion of the defect forms a relatively large defect 13. This is what is happening. Then, in order to fit into these defective parts and prevent the anode electrode 6 from shifting in the plane direction, a movement preventing body 9 having the shape shown in Fig. b is installed so as to surround the entire circumference of the end of the anode electrode 6. It is fitted between the anode electrode 6 and the metal base 3. That is, as shown in FIG. The partial protrusion 17 of the movement prevention body 9 fits into the relatively large defect 13 provided in the
This allows alignment and further prevents rotation of the semiconductor substrate 1. Furthermore, the movement prevention body 9 is
It may be a metal that is easy to process such as Al or Cu, or it may be an inorganic material such as a fluorine-based resin that has good heat resistance and can be processed. With this configuration, the semiconductor substrate 1
It is possible to prevent plane movement and rotational movement of the gate lead wire 4, and the gate lead wire 4 is prevented from being disconnected or twisted, so it is expected that the reliability of the device will be improved. Since the contact surfaces between the metal base 3 and the anode electrode 6 are flat, good conduction of heat and electricity can be ensured between the two, and property deterioration due to prevention of planar movement and rotational movement is avoided. do not have.

Note that the positioning partial protrusions 16 and 17 of the movement preventive body 9 do not need to be provided in the same direction, and may be provided in the reaction direction.

Furthermore, the present invention is applicable not only to the case where the gate lead wire 4 is fixed to the side of the semiconductor substrate as shown in FIG. 2, but also to a so-called center gate structure provided in the center of the semiconductor substrate 1. The effect of this can be obtained.

Furthermore, although the anode electrode has been described as the other main electrode, in the case of an anode gate, the gate lead wire and the anode electrode are provided on one main surface, and the cathode electrode is provided on the other main surface.
In this case, the cathode electrode will be in sliding contact with the metal base as the other main electrode, but even in such a case, if a cutout is provided in the cathode electrode and the metal base and the movement prevention body is fitted, A similar effect can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a schematic cross-sectional view of a conventional pressurized contact type flat thyristor, and Fig. 2 shows an embodiment of the present invention, in which a is a cross-sectional view of the processed anode electrode and metal base, and b is a movement preventive body. c is a cross-sectional view along the A-A cutting line of the movement prevention body shown in b, d
is a cross-sectional view when the anode electrode, anti-movement body, and metal base are combined.

Claims (1)

[Scope of utility model registration request] A gate electrode and one main electrode are bonded with low resistance to one main surface of a semiconductor substrate having a thyristor structure, the other main electrode is connected with low resistance to the other main surface, and a metal cover is attached to the one main electrode and the other main electrode. and a flat thyristor in which the metal bases are in sliding contact with each other, the other main electrode and the metal base are each provided with a defective portion in which the circumferential ends facing each other are non-perfectly circular, and the other main electrode and the metal base are each provided with a defective portion having a non-perfect circular shape, and the other main electrode and the metal base are fitted into the defective portion. 1. A flat thyristor comprising a movement prevention member for the other main electrode relative to a mating metal base.