JPS605562A - Semiconductor device - Google Patents

Abstract

PURPOSE:To prevent the displacement of the positions between a semiconductor element and a contacting electrode plate by inserting the plate formed with an escape such as a through hole or a groove into a semiconductor substrate on which both gate and cathode electrodes are disposed without forming irregular surface on a main surface along a guide formed of an insulating material secured to the gate electrode. CONSTITUTION:A contacting electrode plate guide ring 22 formed of an insulating material such as resin or ceramic of the same profile as the part is secured to the vicinity of the central region of the surface of a gate electrode 2, for example, by an epoxy resin adhesive 23. A central hole is engaged along the outer periphery of the ring 22 formed on the electrode 2, and a contacting electrode plate 6 having a through hole contacted with a cathode electrode 3 is simultaneously mounted. Thus, a semiconductor substrate 1 and the plate 6 are correctly matched by the shape of the ring 22, and the displacement of the positions between them is not caused at all due to the rotation.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field to which the Invention Pertains] The present invention relates to an assembly structure of a semiconductor device having a complex-shaped gate electrode, such as a high-speed thyristor.

[Prior art and its problems]

FIG. 1 is a plan view showing the surface shape of a high-speed thyristor element, and FIG. 2 is an enlarged sectional view taken along the line AA in FIG. 1. 1 and 2, a semiconductor substrate 1 has a complex-shaped gate electrode 2 and a cathode electrode 3 on its main surface. Generally, the electrodes 2 and the cathode electrode 3 are arranged separately from each other to prevent permanent short-circuiting between the two electrodes. The cathode '#i, pole 3 is connected to the outside and the main current flows through it, and the gate electrode 2 is the electrode of the auxiliary thyristor. 4 is a first stage gate electrode connected to the outside.

A sectional view of a flat high speed thyristor device in which a semiconductor element having such a semiconductor substrate is sealed in a container is shown in FIG. 3, and the same reference numerals as in FIGS. 1 and 2 represent the same names.

As shown in FIG. 3, a semiconductor substrate 1 is fixed to a support plate 5 made of molybdenum or tungsten to constitute a semiconductor element 2, and on a cathode electrode 3 of the semiconductor substrate 1,
A contact electrode plate 6 made of a conductive metal 2, such as molybdenum, having a smooth outer surface is brought into contact. The means for arranging the gate electrode 2 and the cathode electrode 3 so that no electrical short circuit occurs is shown in FIGS. This is done by forming a step by etching using a silicon substrate 1, and providing a gate electrode 2 made of an aluminum vapor-deposited film in the recessed part of the silicon substrate 1 and a cathode electrode 3 also made of an aluminum vapor-deposited film on the outermost main surface of the silicon substrate 1. be exposed. Due to the difference in height of the uneven surface provided on the main surface of the silicon substrate 1 as shown in FIG.

A space insulation portion is created, and the gate electrode 2 is kept electrically insulated from the cathode electrode 3 which is in contact with the contact electrode plate 6.

To explain the assembly procedure of the flat semiconductor device shown in FIG. 3, first, the spring member 1o and the insulating member 11 are passed through a container consisting of an electrode 8 and an insulating ring 9 which are soldered together via a flange 7. The gate lead wire 12 is placed on the silicon substrate 1 at a location where its tip is to be brought into contact with the first stage gate electrode 4, and the other end of the gate lead wire 12 is inserted into the tube 13 penetrating the insulating ring 9. Together with the tube 13, the ends are crushed and sealed together. Next, for example, Teflon space ring 1
4 into a container, or make a cut in the space ring 14 at the point where it intersects with the lead wire 12 and insert the lead wire 12 into the space ring 14.
Make sure it doesn't get in the way. Thereafter, a semiconductor element consisting of a contact electrode plate 6, a silicon substrate 1 whose main surface has been previously processed to have irregularities as shown in FIG. 2, and a support plate 5 is arranged as shown in FIG. Flange 1
An electrode 16 is placed on top of the semiconductor element, and the flange 15 and the flange 17 provided on the insulating ring 9 are edge arc welded around the entire circumference of the container, completing the assembly of this flat semiconductor device.

However, due to the structure described above,
This flat semiconductor device inevitably has the following drawbacks.

One of them is that the depth dimension of the four parts formed on the soil surface of the silicon substrate 1 must be controlled to 0.02''O°'m, which is accompanied by processing difficulties.Fourth The figure is an enlarged sectional view showing the relationship between a gate electrode 2, a cathode electrode 3, and a contact electrode plate 6 of a silicon substrate 1 whose main surface is roughened according to the symbols in FIGS. 1 to 3. For example, if the machining depth of the recess on the main surface of the silicon substrate 1 is too shallow than the specified dimension, a protrusion may be formed on the gate electrode 2 due to the poor precision of the photomask and force, as shown in FIG. 18, this protrusion 18 may come into contact with the contact electrode plate 6, resulting in an electrical short circuit between the gate electrode 2 and the cathode electrode 37.
The figure shows a cross-sectional view similar to FIG. 4, but in this case, for example, in the four parts provided on the main surface of the silicon substrate 1,
Because foreign matter 19 such as metal particles was mixed in during the manufacturing process, the gate electrode 2
This indicates that when the contact electrode plate 6 comes into contact with the contact electrode plate 6, a short circuit occurs between the gate and cathode electrodes.

The second drawback is that in the structure of the flat thyristor shown in FIG. 3, the contact electrode plate 6 is brought into contact with pressure only in the use state after the semiconductor element is housed in the container, and the semiconductor element also has a contact electrode plate 6. Since the plate 6 is not always restrained, such a flat silicon risk is caused by damage to the cathode electrode film 3 due to rotation of the semiconductor element sealed in the container or the contact electrode plate 6 during handling. It is extremely fragile and can be scratched and damaged, which may lead to a short circuit between the gate and cathode electrodes.

[Purpose of the invention]

An object of the present invention is to eliminate the above-mentioned drawbacks, and to provide a semiconductor device in which the gate electrode and the cathode electrode are not short-circuited through the contact electrode plate, and the misalignment between the semiconductor element and the contact electrode plate is prevented. There is a particular thing.

[The crux of invention]

The semiconductor device of the present invention has an insulating structure in which a contact electrode plate provided with relief parts such as through holes or grooves is fixed to the gate electrode on a semiconductor substrate in which both gate and cathode electrodes are arranged without providing any unevenness on the main surface. By inserting the contact electrode plate and the semiconductor element along separate guides, the relative positions of the contact electrode plate and the semiconductor element are aligned and fixed.

[Embodiments of the invention]

The present invention will be explained below based on implementation.

Since the semiconductor device of the present invention and its assembly procedure are almost the same as those shown in FIG. 3, only the parts directly related to the present invention will be described. Substrate 1. These are the shape of the contact electrode plate 6 and the structure for fixing the contact electrode plate 6 to the silicon substrate 1. To specifically describe these points using the same symbols and names as in FIGS. 1 to 5, as shown in a partially enlarged cross-sectional view in FIG. Rather, a through hole 20 having the same contour shape and slightly larger than the gate electrode 2 is provided at a portion of the contact electrode plate 6 that is in contact with the cathode electrode 3 and faces the gate electrode 2 . Like FIG. 6, FIG. 7 is also a partially enlarged sectional view, but in this case, the 6th
A groove 21 is provided in the contact electrode plate 6 instead of the through hole 20 shown in the figure.

As you can see from Figures 6 and 7, if you do this,
A concave portion is provided on the main surface of the silicon substrate 1 to form a gate electrode 2.
It is not necessary to arrange the contact electrode plate 6, and the depth dimension of the relief part such as the through hole 20 and groove 21 of a good electrical conductor such as molybdenum used as the contact electrode plate 6 can be set to 0.1 to 0.5 Wtn. The height difference of the unevenness provided on the main surface of the silicon substrate 1, which was considered to be a drawback of 0.02:Il:0・Ol
Even if the gate electrode 2 is contaminated with the protrusion 18 shown in FIG. 4 or the foreign matter 19 shown in FIG. I can handle it. That is, since the gate electrode 2 and the contact electrode plate 6 do not come into direct contact with each other, there is no short circuit between the gate electrode 2 and the cathode electrode 3 via the contact electrode plate 6.

However, this means that the semiconductor substrate 1 and the contact electrode plate 6
are always kept in the correct position and aligned, and if the relative positions of the semiconductor substrate l and the contact electrode plate 6 are shifted due to their respective rotations as described above,
A short circuit may occur due to abrasion of the cathode electrode due to rotation. Therefore, it is necessary to fix the semiconductor substrate 1 and the contact electrode plate 6 and to provide a stopper for rotation of both. 8 and 9 show the semiconductor substrate 1 provided with a guide for inserting the contact electrode plate 6, which serves as a rotation stopper. FIG. 8 is a plan view, and FIG. 9 is a plan view. is the 8th
It is an AA enlarged sectional view of a figure.

8 and 9 have the same reference numerals as in FIGS. 1 to 7.

Although expressed by the same name, a contact electrode plate guide ring 22 made of an insulating material such as resin or ceramic and having the same outline as that part is attached near the center area of the surface of the gate electrode 2 using, for example, an epoxy resin adhesive 23. Indicates a fixed state. FIG. 10 shows a contact electrode plate 6 having a center hole fitted along the outer periphery of a contact electrode plate guide 22 provided on the gate electrode 2, and a through hole that is brought into contact with the cathode electrode 3 at the same time. It is an enlarged sectional view showing the installed state. Thus, in the semiconductor device of the present invention, due to the shape of the guide ring 22 shown in FIG. 8, there is no fear that the positions of the semiconductor substrate 1 and the contact electrode plate 6 will shift due to rotation or the like after they are properly aligned. It turns out that there is none at all.

〔Effect of the invention〕

As explained above, according to the present invention, it is no longer necessary to provide a recess on the main surface of a silicon substrate, which is extremely complicated and whose depth is difficult to control, and to arrange a gate electrode. As soon as a short circuit occurs between the gate and cathode electrodes, the semiconductor device can be stably operated for a long period of time. This effect can be obtained at the position facing the gate electrode, where both the gate and cathode boxes are placed on the contact electrode plate.

This is because a relief part is provided to prevent a short circuit between the electrodes, and the positional relationship between the gate electrode and the contact electrode plate is correctly aligned, but if this relative positional relationship cannot be maintained for some reason. In this case, the problem of short circuit occurs again. The phenomenon that is most likely to cause this is the rotation of the contact electrode plate and semiconductor element during handling after encapsulation assembly, but in the device of the present invention, the contact electrode plate is placed on top of the gate electrode. By fixing stop parts m and b, which are effective in combination, it is possible to eliminate the problem that the contact start plate and the semiconductor substrate rotate independently. That is, the insulating ring fixed to the main part and part of the branch part of the gate electrode fits into the contact electrode plate, thereby preventing rotation. If the purpose is only to stop rotation, it is not necessarily good)
Although the main surface of the semiconductor substrate can be used more widely than just on the E electrode, the reason why the rotation stopper is particularly provided on the gate electrode in the present invention is that the insulator is fixed using an adhesive. In order to take this simple method, the insulator was prevented from reaching the cathode electrode area where the main current flows, and the effective area of the cathode electrode was utilized to the maximum. In other words, the device of the present invention can prevent the rotation of the semiconductor component forming element without any form in the electrical performance of the semiconductor device, and has another advantage that the MB stopper not only prevents the rotation as described above. , also serves as a mounting guide for the contact electrode plate. As described above, since the contact electrode plate and the semiconductor element can continue to accurately maintain a certain relative positional relationship without causing a short circuit, this semiconductor device can always maintain a stable operating state.

[Brief explanation of the drawing]

Fig. 1 is a plan view showing the electrode arrangement of a high-speed thyristor element, Fig. 2 is an enlarged partial sectional view, Fig. 3 is a sectional view of a conventional flat semiconductor device, and Figs. 4 and 5 show the arrangement of electrodes. 6 and 7 are enlarged partial sectional views showing the electrode structure of the present invention; FIG. 8 is a plan view showing a guide layer provided on the gate electrode; FIG. 9 10 is also an enlarged partial sectional view, and FIG. 10 is an enlarged partial sectional view showing the state in which the contact electrode plate of the present invention and the semiconductor substrate are fixed. 1...Silicon substrate, 2...Goo)
Electron &r 3...Cathode as pole, 6...
Contact electrode plate, 20... Through hole, 21...
・Contact electrode plate guide ring, 23...Contact 71 Figure 2 Figure 4 Figure 5 Figure 96 Off figure 8 Figure 29

Claims (1)

[Claims] 1) In a semiconductor substrate having, on the main surface thereof, a first electrode layer connected to an external circuit via a contact electrode plate, and a second electrode layer consisting of a main part and a branch part not connected to the external circuit. , a contact electrode sales company, the contact surface that contacts the first electrode layer, and the second electrode layer, which is provided at a location facing the second electrode layer, and has a main portion and branch portions that are large in size. An insulating ring is provided, which has a relief part from the contact surface, fits into the main part and part of the branch part of the relief part, and is fixed on the second electrode layer. Semiconductor device 0