JPS607386B2 - semiconductor equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a semiconductor device for current control, and more particularly to a semiconductor device for current control that maintains electrical and mechanical stability of the semiconductor device using a glass mold, is highly reliable, and is inexpensive. It is something.

A semiconductor device for current control, generally called a sirensor, is
A cathode terminal, an anode terminal, and a gate terminal are attached to a silicon pellet consisting of four p-n-p-n impurity layers, and the joints are covered with an electrically stable insulator such as a glass film or varnish. Furthermore, in order to prevent the device from breaking due to mechanical stress, the entire device is enclosed in a resin mold or case. However, with the resin mold type, the difference in thermal expansion coefficient between the resin and the metal causes problems such as peeling of the adhesive part and disconnection inside the mold, and the poor adhesion between the metal and the resin causes Moisture gets in and there is a problem with edge humidity.

On the other hand, the Cantype, which is enclosed in a case, has high cost parts and a complicated manufacturing process, resulting in cost problems.

The present invention was made to improve the above-mentioned drawbacks, and its feature lies in that electrical protection and mechanical protection are provided by glass molding a semiconductor pellet.

The figure is a schematic structural diagram showing one embodiment of a glass mold type thyristor manufactured according to the present invention.

The details of the invention will be explained below with reference to the drawings. The semiconductor pellet 5 has a p-type emitter layer 51a and an n-type base layer 5- by diffusing impurities as in a general thyristor.
The structure is called a center gate method in which the gate terminal is taken out from the center, which is made up of b- and p-type base layers 5-c and n-type emitter layers 5-d.

An anode terminal 2 made of Mo, W, etc. is soldered to the p-type layer 51a of this semiconductor pellet with a brazing material 4 made of aluminum, and the other side of the anode terminal 2 that is not in contact with the semiconductor pellet 5 is , an anode lead for connection to an external circuit is attached by welding, wax bale, etc.

A gate terminal 8 made of iron-nickel alloy or the like is bonded to the p-type layer 51c on the opposite side of the semiconductor pellet 5 with a brazing material 6a such as lead-based solder.

Further, a cathode terminal 7 made of iron-nickel alloy or the like is bonded to the n-type layer 5-d with a solder layer 6b made of lead-based solder or the like. The gate terminal 8 and the cathode terminal 7 are concentrically integrated in advance with a high-temperature insulator 9 such as glass or ceramic. It is desirable that this insulator has an end heat property higher than the molding temperature when molding the glass 3 to be performed later, that is, when slurry glass is wound and sintered to form molded glass. Furthermore, when soldering the cathode terminal 7- and the gate terminal 8 with solder, solder has low wettability with silicon, so when using silicon as the semiconductor pellet 5, a metal film is applied to the silicon pellet to be soldered in advance. It is a good idea to set it up. For example, when aluminum is used as the brazing material to be alloyed with the semiconductor pellet 5, the metal film is unnecessary. Next, after etching the end face of the pellet with a chemical etching solution, molding glass 3 is wrapped around the anode terminal 2, semiconductor pellet 5, and cathode terminal 7, and fired at a high temperature.

The molding glass 3 includes a semiconductor pellet 5 and Mo,
By using a material having a similar coefficient of thermal expansion to the anode terminal 2, such as W, damage to the semiconductor pellet 5 and the molded glass 3 can be prevented. On the other hand, when using a material with a different coefficient of thermal expansion than the glass 3 for the cathode terminal 7, the cathode terminal 7 and the molded glass 3 are not glued together, but have a double flange structure to take advantage of the difference in thermal expansion coefficient. By pressing the glass between both flanges, airtightness is improved. This cathode terminal 7 can be bonded to the glass 3 when using a material such as Mo or W that has a coefficient of thermal expansion similar to that of the glass 3.

In the figure, a center gate type thyristor is shown, but it can also be applied to peripheral gate type thyristors, side gate type thyristors, etc., and can be applied not only to thyristors but also to transistors.

In this case, they are arranged uniformly with the cathode terminal in the center and the gate terminal on the outside, and both terminals are brazed to predetermined points on the semiconductor pellet 5, and the remaining surface of the semiconductor pellet is insulated. If it is covered with a film, there will be no problem of short circuit between both terminals. According to the present invention, the surface of the semiconductor pellet is sealed with glass that has stable electrical characteristics, resulting in high reliability.Since this molded glass also provides mechanical protection, the assembly process is easy and costs are reduced. A semiconductor device can be obtained.

[Brief explanation of the drawing]

The figure is a schematic structural diagram showing an embodiment of a current control semiconductor device according to the present invention. 1... Anode lead, 2... Anode terminal, 3...
...Mold glass, 4... Brazing material, 5... Semiconductor pellet, 6a, 6b... Brazing material, 7... Cathode terminal, 8... Gate terminal, 9... Insulator.

Claims (1)

[Claims] 1. In a semiconductor device having a semiconductor pellet and a cathode terminal, an anode terminal, and a gate terminal soldered to the pellet, the cathode terminal and the gate terminal have a concentric integral structure with an insulator interposed therebetween, and A semiconductor device characterized in that after brazing a semiconductor pellet and an anode terminal, the outer terminal of the integrated cathode terminal and gate terminal, the anode terminal, and the semiconductor pellet portion are molded with glass.