JPH02254734A - Manufacture of pressure contact type semiconductor device - Google Patents

Abstract

PURPOSE:To assure the bevelling process easily at low cost by a method wherein a holding plate to be fixed on the main surface of a semiconductor substrate for mechanical reinforcement is taken into ring shape so that the outer periphery of the semiconductor substrate may be beveled easily. CONSTITUTION:A ring type holding plate 2 in the same diameter as that of a semiconductor substrate 1 is fixed on the main surface of the substrate 1 so that the outer periphery of the substrate 1 may not jut out of the outer periphery of the holding plate 2 and then the outer periphery of the semiconductor substrate 1 is beveled. That is, the outskirts only of the outer periphery of the semiconductor substrate 1 are reinforced against any mechanical force. Through these procedures, any discrepancy such as cracking and cutout in the semiconductor substrate 1 can be prevented from occurring: this enables the material cost of the holding plate 2 to be cut down.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of manufacturing a pressure contact type semiconductor device.

[Conventional technology]

In semiconductor devices such as flat diodes and flat silices, electrodes are attached to each main surface of the semiconductor substrate by pressurized contact rather than by brazing or the like to achieve ohmic contact. A so-called pressure contact structure is generally adopted.

Incidentally, in semiconductor devices, bevelling is applied to the outer periphery of the semiconductor substrate in order to ensure voltage resistance.
In the case of the above structure, if the outer periphery of the semiconductor substrate is machined to form a bevel with an inclined surface, the semiconductor substrate as it is will crack.

Problems such as chipping are likely to occur. Conventionally, in order to prevent such problems, as shown in the cross-sectional view of FIG. After the semiconductor substrate element 10 is fixed with brazing to give it mechanical strength, the dotted line portion on the outer periphery of the semiconductor substrate element 10 is mechanically removed to form an inclined surface, and further chemical treatment is performed to form a beveled semiconductor substrate. The semiconductor substrate element 10 has a metal support plate fixed to its main surface, and electrode plates are brought into pressure contact with both main surfaces of the semiconductor substrate element 10 to form a semiconductor device.

[Problem to be solved by the invention]

In the conventional manufacturing method as described above, the electrode plate is brought into pressure contact with one main surface of the semiconductor substrate via the support plate.
This supporting plate must be made of a metal with good conductivity, and the supporting plate and the semiconductor substrate must be fixed to each other to form good ohmic contact. Therefore, alloying methods using A1 or the like or hard brazing have been used. Furthermore, it is desirable that the metal used as the support plate has high mechanical strength and a coefficient of thermal expansion comparable to that of the semiconductor substrate, so taking these points into consideration, it is necessary to use Mo, W, or the like. However, the material cost of Mo and W is particularly high compared to other metals, and the cost of fixing them is also high, so the problem is that the manufacturing cost combined with these costs ends up being high. .

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and provide a method for easily and reliably beveling the outer periphery of a semiconductor substrate and manufacturing a pressure contact type semiconductor device at low cost.

[Means to solve the problem]

According to the present invention, in a method of manufacturing a pressure contact type semiconductor device, a ring-shaped support plate having an outer diameter equal to or slightly larger than that of the semiconductor substrate is provided on one principal surface of the semiconductor substrate. After the outer periphery of the semiconductor substrate is fixed so that it does not protrude beyond the outer periphery of the ring-shaped support plate, and the outer periphery of the semiconductor substrate is beveled, the semiconductor substrate is provided on the substrate surface of the inner ring portion of the ring-shaped support plate. This problem can be solved by using a manufacturing method in which electrode plates are connected to the electrode surface and the electrode surface on the other main surface, respectively, so as to maintain airtightness of the substrate and are brought into contact with each other under pressure.

[Effect]

In order to perform bevelling on the outer periphery of a semiconductor substrate without causing defects such as cracks or chips, it is not necessary to reinforce the entire surface of the semiconductor substrate, but only the vicinity of the outer periphery needs to be reinforced against mechanical force. That's fine. Therefore, even if the support plate is formed into a ring shape that reinforces only the vicinity of the outer periphery, the purpose is achieved, and the material cost of the support plate can be reduced accordingly.

In addition, since the ohmic contact of the electrode plate to the semiconductor substrate was obtained by directly pressing the electrode plate into contact with the electrode surface of the semiconductor substrate on the inner side of the ring of the support plate, the semiconductor substrate and the ring-shaped support plate It is no longer necessary to use methods such as alloying with Al or hard brazing for fixing, and it is also possible to use adhesives for fixing, for example, which further reduces the number of steps required for fixing. becomes possible. Furthermore, since the material of this ring-shaped support plate does not need to be electrically conductive, it is also possible to use an inexpensive insulating material to reduce the material cost.

〔Example〕

FIG. 1 shows an embodiment of the present invention in which a ring-shaped support plate is fixed to a semiconductor substrate, in which (a) is a plan view, and (b) is a sectional view taken along line XX in (a). , 1 is a semiconductor substrate, 2 is a ring-shaped support plate made of Mo, W, etc., and 3 is an adhesive for fixing both. The outer diameter of the ring-shaped support plate 2 must be the same as or slightly larger than the semiconductor substrate 1, and both should be positioned so that the outer periphery of the semiconductor substrate 1 does not protrude from the outer periphery of the ring-shaped support plate 2. They must be aligned and fixed in such a way that the outer periphery of the semiconductor substrate can be reliably mechanically protected during the beveling process. The semiconductor substrate 1 and the ring-shaped support plate 2 may be fixed together by an alloying method using Al or by hard brazing. Even in this case, since the support plate is ring-shaped, the material cost is reduced compared to the conventional method, which is effective. Further, the material of the ring-shaped support plate 2 may be an insulating material such as ceramic.

2 and 3 are cross-sectional views of the semiconductor substrate 1 to which the ring-shaped support plate 2 shown in FIG. 1 is fixed, with bevels of different shapes formed on the outer periphery of the semiconductor substrate 1, respectively. Figure 3 is E
An example in which a bevel is formed is shown, and it is effective in cases where both forward and reverse withstand voltages are required, such as in Cyrisk.

Figure 4 is a cross-sectional view of an embodiment of a semiconductor device with a pressure contact structure manufactured using the semiconductor substrate subjected to the beveling process shown in Figure 2, in which a ring-shaped support plate 2 is fixed and the outer periphery is The electrode plate 5 is brought into pressure contact with the bidirectional surface of the semiconductor substrate l, which has been beveled, and the envelope 4 is further applied from the outside.
An outer electrode plate 6 fixed to the substrate 1 hermetically seals the substrate 1 and is in pressure contact with the substrate 1. The inner electrode plate 5 on the side of the semiconductor substrate 1 to which the ring-shaped support plate 2 is fixed is in contact with the surface of the semiconductor substrate l inside the ring of the ring-shaped support plate 2. The semiconductor device is energized via the inner electrode plate 5, and the ring-shaped support plate 2 is structured so as not to be involved in the energization. Therefore, there is no need for ohmic contact between the ring-shaped support plate and the semiconductor substrate. Also,
The material of the ring-shaped support plate does not necessarily have to be conductive.

〔Effect of the invention〕

According to this invention, in manufacturing a pressure contact type semiconductor device, a ring-shaped support plate is used as a support plate that is fixed to one principal surface of the semiconductor substrate for mechanical reinforcement in order to perform a beveling process on the outer periphery of the semiconductor substrate. Therefore, the material cost of the support plate can be reduced compared to the conventional method.

In addition, since the electrode plate is brought into direct pressure contact with the main surface of the ring-shaped support plate of the semiconductor substrate on the fixed side without intervening the support plate, the fixation between the semiconductor substrate and the support plate is achieved by ohmic contact. There is no need to do this, and an alloying method using Al,
Alternatively, hard brazing is not necessarily necessary, and if adhesive is used for fixing, for example, material costs can be reduced, and since fixing can be done easily, the number of man-hours can also be reduced.

Furthermore, since there is no need to make the ring-shaped support plate electrically conductive, it becomes possible to use a support plate made of an insulating and inexpensive material, and there is also the possibility of further reducing material costs. In this way, the beveling process on the semiconductor substrate can be easily and inexpensively performed, and a pressurized contact type semiconductor device with low manufacturing cost can be obtained. 1! The effects achieved by the manufacturing method are significant.

[Brief explanation of drawings]

FIG. 1 shows an embodiment of the present invention in which a ring-shaped support plate is fixed to a semiconductor substrate. FIG. 1(a) is a plan view, and FIG. -X sectional view, FIGS. 2 and 3 are sectional views of an embodiment in which bevels of different shapes are formed on the outer periphery of the semiconductor substrate to which the ring-shaped support plate is fixed as shown in FIG. 1, and FIG. FIG. 2 is a cross-sectional view of an example of a semiconductor device manufactured using a bevel-shaped semiconductor substrate, and FIG. 5 is an example of a semiconductor device in which a bevel is formed on the outer periphery of a semiconductor substrate to which a conventional support plate is fixed. FIG. 1 Semiconductor substrate, 2 Ring-shaped support plate, 3 Connector Figure 1 Figure 2 Ward Atsushi Figure 5

Claims (1)

[Claims] 1) A ring-shaped support plate having the same diameter or a slightly larger outer diameter than the semiconductor substrate is fixed to one main surface of the semiconductor substrate so that the outer periphery of the substrate does not protrude from the outer periphery of the ring-shaped support plate, and further,
After bevelling the outer periphery of the substrate, electrode plates are attached to the electrode surface provided on the substrate surface of the ring-inside portion of the ring-shaped support plate and the electrode surface on the other main surface to ensure airtightness of the substrate. 1. A method of manufacturing a pressure contact type semiconductor device, characterized in that the semiconductor device is made to have a structure in which the pressure is maintained and the device is brought into contact with pressure.