JPS6050340B2 - semiconductor element - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a semiconductor element that is used by directly brazing a conductive portion on the outer surface of a container to a circuit conductor on a substrate such as a printed circuit without using lead wires.

2. Description of the Related Art Connecting circuit components to printed circuits on insulating substrates to construct electronic circuits is widely practiced. Conventionally, to connect semiconductor devices in this way, the lead wires of the devices are inserted into holes in the board and brazed to circuit conductors on the board. However, with the advancement of mounting technology, especially automatic mounting technology,
It has become desirable to develop a so-called leadless type semiconductor element that can be directly brazed to a circuit conductor without using lead wires. FIG. 1 shows an example of the structure of a leadless diode devised by the present inventors to meet this demand.

This diode includes a semiconductor body 1, two electrode bodies 2 in contact with both J surfaces of the semiconductor element body 1, and a glass tube body 3 spanning between the two electrode bodies 2, each of which is a cylindrical body with a large cross section. The end surface 2 of the convex part 21 is coaxially joined together with a convex part 22 having a small cross section (this joint is cylindrical).
3 in contact with each surface of the semiconductor body 1, and the glass tube body 3
is in close contact with the inner end surface 24 of the cylindrical portion 21 having a large cross section and the outer circumferential surface 25 of the convex portion of both electrode bodies 2, thereby hermetically sealing the element body 1. This diode is characterized in that it can be directly connected to a circuit conductor through the cylindrical portion 21, and that its structure and assembly are extremely simple. However, in this case, it has been found that the following problems occur when fusing the glass tubes. That is, in order to seal a semiconductor element having this structure, the semiconductor element 1, both electrode bodies 2, and the glass tube body 3 are assembled and put into an assembly jig 4 shown in FIG. 2, and a force is applied to press both electrode bodies 2 together. The glass tube body 3 is heated while adding
It is fused to the outer circumferential surface 25 of No. 2. At this time, if a large beam is added to ensure that the convex end faces 23 of both electrode bodies 2 and the electrodes on both sides of the semiconductor element 1 are in contact with each other, the inner end face 24 of the cylindrical part with a large cross section of both electrode bodies 2 may be pressed against the end face of the glass tube 3 with a strong force.

Such pressure may cause the glass of the glass tube 3 to protrude outward, damaging the finished shape of the element, as shown in part A of FIG. 2, or may cause glass to adhere to the assembly jig 4, reducing work efficiency. or It is an object of the present invention to provide a leadless type semiconductor element which does not have such disadvantages and has good accuracy in external dimensions after sealing.

The purpose of this is to provide a temporary structure in which at least one of both electrode bodies is in contact with the inner end surface of the cylindrical portion and the outer circumferential surface of the convex portion. This is achieved by having a shape that creates a gap between it and the imaginary cylindrical surface.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 3a shows an example of the electrode body 2 based on the present invention, in which the convex portion 2
2 has a constriction 26 at the base thereof, and a gap 6 is created between it and the virtual cylindrical surface 5 shown by chain dotted lines. One electrode body 2a is placed on the bottom 8 of the cavity 7 of the assembly jig 4 shown in FIG. 4, and the glass tube body 3 shown in FIG. Place the semiconductor body 1 on 23a, and finally insert the convex portion 22b of another electrode body 2b into the hole of the glass tube 3 until the inner end surface 24b of the cylindrical portion 21b contacts the end surface of the glass tube 3. . Next, when this assembly jig is heated in an inert gas atmosphere to melt the glass tube body 3, the electrode body 2b will be caused by its own weight to cause the convex end surface 23b to bend over the semiconductor element body 1.
sink until it touches the upper electrode. At this time, a part of the molten glass fills the constrictions 26a and 26b at the bases of the protrusions 22a and 22b as shown in part B, so the glass tube 3 does not bulge outward, and the assembly and sealing is prevented. No abnormality occurs in the external shape of the finished leadless diode. In this case, even if the constriction 26 is not completely grooved with glass due to dimensional variations in each component, no particular problem will occur. FIG. 5a shows a different embodiment of the electrode body 2, in which a groove 27 is provided on the inner end surface 24 of the cylindrical portion 21 to create a gap 6 between it and the virtual cylindrical surface 5. FIG. If this electrode body 2 is fitted into the glass tube 3 shown in FIG. 5b and sealed in the same manner as shown in FIG. It does not protrude to the radial side. FIG. 6a shows another embodiment of the electrode body, in which the inner end surface 24 of the cylindrical portion 21 of the electrode body 2 is an inclined surface. Therefore,
A gap 6 is created between the virtual cylindrical surface 5 and the end surface. If this electrode body 2 and the glass tube body 3 shown in FIG. 6b are sealed in the same manner as shown in FIG. 4, the glass tube body 3 will be pushed by the electrode body 2 and as shown in FIG. It is in close contact with the inner end surface 24 of the cylindrical portion 21 of the electrode body 2 and does not protrude toward the outer diameter side. 7a and 8a each show another embodiment of the electrode body according to the invention, in which the convex portion 22 has a conical shape. Accordingly, the shape is such that a gap 6 is created between the virtual cylindrical surface 5 and the outer peripheral surface 25 of the convex portion 22. Using these electrode bodies 2 and the glass tube bodies 3 shown in FIGS. 7b and 8b, respectively, a fourth
If the sealing is performed in the same manner as shown in the figure, the excess glass will be removed from the outer circumferential surface of the convex portion 22 of the electrode body 2, as shown in FIG. 7 C1 and FIG. 8 C.
5, and no abnormality occurs on the outer diameter side. In any of these electrode bodies, even if the gap between the electrode body and the virtual cylindrical surface is not completely filled, there is no problem in practicality as a semiconductor device. In each of the above examples, electrode bodies of the same shape are used on both sides of the semiconductor body, but the electrode body that becomes the lower side when glass is fused has a cylindrical part with a large diameter as shown in Figure 1. An electrode body consisting of a cylindrical portion with a small diameter may be used, and only the upper electrode body may have an electrode body whose shape is changed based on the present invention.

It is also possible to use an electrode body having a plurality of gaps between it and the virtual cylindrical surface. As described above, the semiconductor element according to the present invention uses an electrode body having an excessive glass relief part, and has the characteristic that the glass tube body does not protrude to the outer diameter side during fusion bonding.

As a result, extremely large effects such as stabilization of the finished shape of leadless semiconductor elements, improved workability, complete electrical contact between the electrode body and the electrode of the semiconductor body, and absorption of dimensional variations of each component have been achieved. Obtainable.

[Brief explanation of the drawing]

Figure 1 is a vertical cross-sectional view of a conventional example of a leadless diode.
FIG. 2 is a side sectional view showing the state of assembly of the diode shown in FIG. 1, FIG. FIG. 4 is a longitudinal sectional view of the tube body, FIG. 4 is a side sectional view showing the state of assembly of the diode using the parts shown in FIGS. 3A and 3B, and FIGS. 5 to 8 each show different embodiments of the present invention. ,a
is a vertical cross-sectional view of an electrode body, b is a glass tube body, and c is a finished diode. 1... Semiconductor element body, 2... Electrode body, 21...
...Cylindrical part, 22...Convex part, 24...Inner end surface of columnar part, 25...Outer periphery of convex part, 3...
...Glass tube body, 5...Virtual cylindrical surface, 6...
void.

Claims (1)

[Claims] 1. A semiconductor body, two electrode bodies in contact with both surfaces of the body, and a glass tube body spanning between the two electrode bodies, each of which has a large cylindrical section. and a convex portion with a small cross section are coaxially coupled together, and the end surfaces of the convex portion contact each surface of the semiconductor body, and the glass tube body is a cylindrical portion having a large cross section of both electrode bodies. The element body is hermetically sealed by being in close contact with the inner end face of the cylindrical part and the side surface of the convex part, and at least one of the electrode bodies is in contact with the virtual cylindrical face which is in contact with the inner end face of the cylindrical part and the outer peripheral surface of the convex part. 1. A semiconductor element characterized by having a shape such that a void is formed between the elements. 2. A semiconductor device according to claim 1, wherein at least one of the electrode bodies has a constriction on the side surface of the convex portion. 3. A semiconductor device according to claim 1, wherein at least one of the electrode bodies has a groove on the inner end surface of a cylindrical portion having a large cross section. 4. The semiconductor device according to claim 1, wherein the inner end surface of at least one cylindrical section having a large cross section of the electrode body is an inclined surface. 5. A semiconductor device according to claim 1, wherein at least one outer circumferential surface of the convex portion of the electrode body is a conical surface.