JPS6127901B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a structure for positioning a main electrode plate of a pressure contact type semiconductor device.

In this specification, the term "main electrode plate" includes a plate having a through hole through which a gate lead is inserted.

A description will be given below using a semiconductor-controlled rectifier as an example.

FIG. 1 is a longitudinal cross-sectional view of a main part of an example of a conventional pressurized contact type semiconductor-controlled rectifier. In FIG. 1, 1 is a silicon wafer which is a semiconductor substrate having a PNPN structure, 2 is a gate electrode made of an aluminum vapor deposited layer and formed on the center of one main surface of the silicon wafer 1, and 3 is a gate electrode made of an aluminum vapor deposited layer. The cathode electrode 4, which is one of the main electrodes, is formed on the main surface on which the gate electrode 2 is formed, surrounding the gate electrode 2, and is made of a material such as molybdenum or tungsten, which has a coefficient of thermal expansion almost equal to that of silicon. An anode electrode is brazed to the other main surface of the silicon wafer 1, a gate lead 5 is made of an elastic metal body and one end is brought into pressure contact with the gate electrode 2 by the spring force of the elastic metal body, and 6 is made of an insulator. A gate support rod 7 supports the gate lead 5 so as not to come into contact with a cathode ring and a cathode copper block, which will be described later, and a cathode electrode 7 is made of a material such as molybdenum, tungsten, or an iron-nickel alloy, which has a coefficient of thermal expansion almost equal to that of silicon. 3 is a cathode ring which is a main electrode plate which is brought into pressure contact with the cathode ring 7; 8 is a cathode copper block which is one main electrode conductor which is brought into pressure contact with the cathode ring 7; and 9 is the other which is brought into pressure contact with the anode electrode 4. The main electrode conductor is the anode copper block.

The gate lead 5 and the gate electrode 2, and the cathode ring 7 and the cathode electrode 3 must be positioned so that their positions do not deviate from each other. For this reason, in the conventional semiconductor-controlled rectifier, the gate support rod 6 is positioned through a hole drilled in the center of the cathode copper block 8, and the cathode ring 7 is positioned around the outer periphery of the gate support rod 6. However, in the conventional structure described above, when assembling each component in sequence, the cathode ring 7 easily comes off the gate support rod 6 and moves.
However, there was a problem in that gate electrode 2 and gate electrode 3 were short-circuited.

This invention has been made in view of the above points, and by providing a peripheral wall surrounding the outer periphery of the main electrode conductor and positioned on the main electrode conductor in the peripheral part of the main electrode plate, the main electrode It is an object of the present invention to provide a pressurized contact type semiconductor device in which positional displacement of the plate does not occur.

The present invention will be described below based on an example in which the present invention is applied to a semiconductor-controlled rectifier.

FIG. 2 is a longitudinal sectional view of a main part of an embodiment of a pressurized contact type semiconductor-controlled rectifier according to the present invention. In FIG. 2, the same reference numerals as in FIG. 1 represent the same components as shown in FIG. 7a is made of molybdenum, tawagsten, iron-nickel alloy, etc., which has a coefficient of thermal expansion almost equal to that of silicon, and has a peripheral wall surrounding the outer periphery of the cathode copper block 8, and extends from the inner peripheral surface of this peripheral wall to the outer peripheral surface of the cathode copper block 8. The cathode ring is positioned on the cathode copper block 8 by at least three protrusions 71 provided so as to come into contact with the cathode copper block 8.
FIG. 3 is a plan view of the cathode ring of the embodiment of FIG. 2.

In the structure of the embodiment, when assembling each component in sequence, the cathode ring 7a does not come off from the cathode copper block, so the cathode ring 7a moves and the gate electrode 2 and cathode electrode 3 are short-circuited or misaligned. It is possible to completely prevent problems such as the silicon wafer 1 being cracked or cracked due to excessive pressure being applied to a portion of the silicon wafer 1. Therefore, the semiconductor-controlled rectifier of the embodiment has high reliability. Moreover, assembly work is easy. Further, since the cathode ring 7a does not need to be positioned by the gate support rod 6, a thin plate can be used for the cathode ring 7a, which is made of expensive materials such as molybdenum and tungsten, and can be manufactured at low cost.

In the above embodiment, the present invention was applied to a semiconductor-controlled rectifier, but the present invention can also be applied to stud-type or flat-type pressurized contact type semiconductor devices such as power diodes, triacs, and reverse conduction thyristors. It can be widely applied.

As explained above, in the pressure contact type semiconductor device according to the present invention, the main electrode plate has a peripheral wall surrounding the outer periphery of the main electrode conductor and positioned on the main electrode conductor. This prevents malfunctions such as misalignment of the electrode plate, resulting in a short circuit between the main electrode and other electrodes, or partial excessive pressure contact between the main electrode plate and the semiconductor substrate, which may cause the semiconductor substrate to crack or crack. Completely preventable.
Further, a thin plate can be used for the main electrode plate. Therefore, the pressurized contact type semiconductor device according to the present invention has the following features:
It is more reliable, easier to assemble, and lower in price.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of a main part of an example of a conventional pressurized contact type semiconductor-controlled rectifier, and FIG. 2 is a longitudinal cross-sectional view of a main part of an embodiment of a pressurized contact type semiconductor-controlled rectifier according to the present invention. , FIG. 3 is a plan view of the cathode ring of the embodiment of FIG. 2. In the figure, 1 is a silicon wafer (semiconductor substrate), 3 is a cathode electrode (main electrode), 7 and 7a are cathode rings (main electrode plate), 71 is a protrusion, and 8 is a cathode copper block (main electrode conductor). be. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Scope of Claims] 1. A semiconductor substrate having at least one PN junction, a main electrode provided on one main surface of the semiconductor substrate, and the main electrode made of a material having a coefficient of thermal expansion substantially equal to that of the material of the semiconductor substrate. In a device comprising a main electrode plate that is brought into pressure contact with the main electrode plate and a main electrode conductor that is brought into pressure contact with the main electrode plate, a surface of the main electrode plate on the side of the main electrode conductor is provided with a 1. A pressure contact type semiconductor device comprising a rising wall that rises toward the side and is positioned against a side wall of a main electrode conductor. 2. The pressurized contact type semiconductor device according to claim 1, wherein the peripheral wall of the main electrode plate has at least three protrusions on its inner periphery that are engaged with the outer peripheral surface of the main electrode conductor. . 3. The pressure contact type semiconductor device according to claim 1 or 2, wherein the main electrode plate has a through hole through which a gate lead is inserted.