JPH09232562A - Pressure-welded semiconductor device and semiconductor element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To uniformly transmit a gate signal by providing a gate lead wire with one mounting portion thereof facing outside other outer peripheral surfaces within a groove portion without contacting other inner surfaces of the groove portion. SOLUTION: A semiconductor substrate 18 has a segment which is formed on a ring facing toward an outer peripheral surface or toward a lateral surface portion 18S from a center axis 31. A center gate layer corresponding to a center gate electrode 16 is formed on an exposed surface of a p-layer, and a cathode layer is formed on the surface of an n-layer. An anode layer is formed on the back side of the p-layer. The center gate layer electrically contacts the center gate electrode 16. A part of one mounting portion 19 of a gate lead wire 17 is arranged at a part within a groove portion and fixed and supported to the center gate electrode 16. A part of the other mounting portion 21 is fixed and supported within a through-hole 43 provided in an insulating cylinder 15. Thus, attenuation of gate signals may be restrained and miniaturization of shape dimension may be promoted. Also, the gate signals may be uniformly transmitted to the segment.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure contact type semiconductor device and a semiconductor element, and more particularly to a pressure contact type semiconductor device or a semiconductor element in which a semiconductor substrate is in contact with a center gate electrode or a center electrode. It is a thing.

[0002]

2. Description of the Related Art FIG. 9 is a vertical sectional view showing the structure of a conventional pressure contact type semiconductor device. In the figure, each reference numeral indicates the following. That is, 1 is a cathode electrode, 2 is an anode electrode, 4 is a cathode heat compensation plate, 3 is an anode heat compensation plate,
Reference numeral 8 is a semiconductor substrate pressed against both electrodes 1 and 2 via both heat compensation plates 3 and 4, 6 is a center gate electrode, 7 is a gate lead wire for transmitting a gate signal input from the outside,
Reference numeral 5 is an insulating cylinder for hermetically sealing the pressure contact type semiconductor device.

One end of the gate lead wire 7 is fixed to the outer peripheral surface of the center gate electrode 6 by brazing, and the other end is inserted into a through hole in the insulating cylinder 5 and fixed by brazing.

Center gate electrode 6 and gate lead wire 7
In order to clearly show the mounting portion 9 of the and, their side and plan views are shown in FIGS. 10 and 11, respectively.

The gate lead wire 7 is a metal conductor rod (round bar) having a circular cross section, and is made of, for example, Ag.

Next, the operation of the apparatus will be described. By press-contacting the cathode electrode 1 and the anode electrode 2 from the outside, the cathode electrode 1, the anode electrode 2, the cathode heat compensation plate 4, the anode heat compensation plate 3, and the semiconductor substrate 8 are brought into contact with each other. As a result, the external gate signal is transmitted from the gate lead wire 7 to the center gate electrode 6, and the gate signal is sent into the semiconductor substrate 8. At this time, when the gate signal is an ON signal, each segment of the semiconductor substrate 8 becomes conductive, and a main current or an anode current can flow from the anode electrode 2 to the cathode electrode 1.

On the contrary, when the gate signal is an off signal, the semiconductor substrate 8 is in a blocking state, and the current can be stopped by this pressure contact type semiconductor device.

With the above-described operation, this pressure contact type semiconductor device enables large capacity current control.

[0009]

Since the conventional pressure contact type semiconductor device is constructed as described above, there are roughly two problems.

First, in the conventional technique, as shown in FIG.
0 and FIG. 11, since the gate lead wire 7 is attached to the center gate electrode 6 at the side surface portion or the outer peripheral portion of the center gate electrode 6, the gate signal input to the center gate electrode 6 becomes uneven. As a result of being transmitted through the semiconductor substrate 8 and concentrating a gate signal (here, a gate current) in a local portion of the semiconductor substrate 8, the semiconductor substrate 8
That is, the characteristics of each of the segments are deteriorated. In particular, it becomes difficult to turn on, and the turn-on characteristics are significantly deteriorated. Therefore, in the pressure contact type semiconductor device using the semiconductor element having the center gate structure, improvement of the ON characteristics of the semiconductor element is demanded.

The second point is as follows. if,
If the resistance or impedance of the gate portion formed by the center gate electrode 6 and the gate lead wire 7 is large, the attenuation of the gate signal transmitted through the gate portion will occur remarkably, and it is necessary to suppress such attenuation. . For this purpose, the wire diameter of the gate lead wire 7 must be increased to some extent, and for example, the wire diameter is set to φ3 mm. Then, it is necessary to set the size of the mounting portion 7 between the gate lead wire 7 and the center gate electrode 6 to be large, which increases the cost of the gate lead wire and increases the brazing work of the mounting portion 7 and brazing. As a result of an increase in the cost of the part, there arises a problem that the reliability of brazing of the mounting part is reduced. Similarly, regarding the mounting portion on the insulating cylinder 5 side, the reliability of brazing becomes a problem.

The present invention has been made in order to solve the above-mentioned problems, and it is possible to set the gate portion to a compact size while suppressing the attenuation during the transmission of the gate signal, and at the same time, in the semiconductor substrate. It is an object of the present invention to obtain a pressure contact type semiconductor device or semiconductor element capable of uniformly transmitting a gate signal transmitted from the outside to each of the segments.

[0013]

According to a first aspect of the present invention, there is provided a pressure contact type semiconductor device in which a plurality of segments are formed in a ring shape from a central axis side thereof to a side surface side thereof, and a central position thereof. A center gate electrode contacting and arranged on the one main surface of the semiconductor substrate so as to match the center position of the one main surface of the semiconductor substrate, and the center gate electrode from a part of the outer peripheral surface of the center gate electrode. The groove formed in the center gate electrode itself up to the center position of the center gate electrode, and one end of one of the mounting portions on the inner surface of the groove at the center position of the center gate electrode is the center gate. A gate lead wire that is fixed to the electrode and transmits a gate signal for controlling the on and off operations of the segment from the outside to the center gate electrode. For example, the one mounting portion of the gate lead wire except for the one end portion, said without contact with the other inner surface of the groove, the groove portion is disposed outward of the outer peripheral surface.

The gate signal is transmitted from the outside to the inner surface of the groove portion at the central position without being transmitted to the other inner surface of the groove portion except the fixed portion at the one end portion of the one mounting portion, and as a result, the central position of the semiconductor substrate. From the inside to the outer peripheral surface in a radially uniform manner within the semiconductor substrate. Due to the uniform transmission of the gate signal, each segment located around the center gate electrode is efficiently and uniformly controlled to be turned on. Therefore,
The characteristics of each segment are dramatically improved.

A pressure contact type semiconductor device according to a second aspect of the present invention is the pressure contact type semiconductor device according to the first aspect, wherein the width and the depth of the groove are set to be larger than the width and the thickness of the gate lead wire, respectively. Is.

The mechanical condition is that the gate signal from the outside is reliably transmitted to the inner surface of the groove portion at the center position without being transmitted to the other inner surface of the groove portion except the fixed portion at the one end of the one mounting portion. -It is a condition for supplying. That is,
By setting this mechanical condition, it is possible to surely arrange the inside of the groove portion to the inner surface of the groove portion at the center position without contacting the gate lead wire with the other inner surface of the groove portion except the fixed portion, Then, it becomes possible to fix the gate lead wire to the center gate electrode on the inner surface of the groove at the center position. Moreover, since the gate lead wire is completely housed in the groove, it is possible to provide a gate lead wire structure suitable for a pressure contact type semiconductor device.

A pressure contact type semiconductor device according to a third aspect of the present invention is the pressure contact type semiconductor device according to the first or second aspect, wherein the gate lead wire has the one mounting portion whose other end protrudes from the groove portion. , A lead portion whose one end is connected to the other end of the one attachment portion, and another attachment portion whose one end is connected to the other end of the lead portion and which has the same shape and size as the one attachment portion. It is assumed that only the lead portion is formed by rolling.

The surface area per unit length of the lead portion can be made significantly larger than those of the one and the other mounting portions while the sectional area of the lead portion is the same as that of the one and the other mounting portions. . As a result, the resistance or impedance of the gate lead wire can be significantly reduced due to the skin effect. As a result, it is possible to sufficiently suppress the attenuation of the gate signal when transmitting on the gate lead wire.

Therefore, in accordance with the reduction of the resistance of the gate lead wire, it is possible to set the size of one and the other mounting portion of the gate lead wire to be smaller. As a result, it is possible to reduce the cost of the gate lead wire and
It is possible to set a small fixing area between the one mounting portion of the gate lead wire and the inner surface of the groove portion at the center position of the center gate electrode. This fixing work can be facilitated and the cost can be reduced. The reliability can be dramatically improved.

A pressure contact type semiconductor device according to a fourth aspect of the present invention is the pressure contact type semiconductor device according to the third aspect, wherein the rolling direction of the lead portion is set in the direction normal to the one main surface of the semiconductor substrate. It is a thing.

This makes it possible to provide a gate lead wire structure suitable for a pressure contact type semiconductor device.

A pressure contact type semiconductor device according to a fifth aspect of the present invention is the pressure contact type semiconductor device according to the fourth aspect, wherein the pressure contact type semiconductor device is disposed on a predetermined portion of the one main surface excluding a portion where the center gate electrode is formed. It further comprises a first heat compensating plate, and a first electrode that press-contacts the one main surface of the semiconductor substrate via the first heat compensating plate, and the first electrode facing the first heat compensating plate. On the back surface side of the electrode, another groove portion whose shape and size are set so as not to contact the center gate electrode, the one mounting portion and the lead portion is formed.

The width of another groove portion can be reduced,
The cost required for forming another groove can be reduced, and the contact area between one main surface of the semiconductor substrate and the first electrode via the first heat compensating plate can be increased.

A pressure contact type semiconductor device according to a sixth aspect of the present invention is the pressure contact type semiconductor device according to the fifth aspect, wherein a second heat compensation plate is disposed on the other main surface of the semiconductor substrate.
It further comprises a second electrode that press-contacts the other main surface of the semiconductor substrate via the second heat compensating plate, and insulating cylinders fixed to respective side surfaces of the first electrode and the second electrode. And the other mounting portion of the gate lead wire is fixed to the insulating cylinder.

Since the size of the other mounting portion of the gate lead wire can be set small, the area of the fixed portion between the other mounting portion and the insulating cylinder can be reduced,
This fixing work can be facilitated and costs can be reduced,
Therefore, the reliability of the fixed portion can be significantly improved.

According to a seventh aspect of the present invention, there is provided a pressure contact type semiconductor device in which a plurality of segments are formed in a ring shape from the central axis side to the side surface side of the semiconductor substrate and the center position is one of the semiconductor substrates. A center gate electrode that is in contact with and arranged on the one main surface so as to match the center position of the main surface, one and the other mounting portions, and a lead portion that connects the one and the other mounting portions. A gate lead wire having one end of the one attachment portion fixed to the center gate electrode and transmitting a gate signal for controlling the on and off operations of the segment to the center gate electrode. And only the lead portion of the gate lead wire is formed by rolling.

While the cross-sectional area of the lead portion is the same as the cross-sectional area of one mounting portion, the surface area per unit length of the lead portion can be made significantly larger than that of one mounting portion. As a result, the resistance or impedance of the gate lead wire can be significantly reduced due to the skin effect. As a result, it is possible to sufficiently suppress the attenuation of the gate signal when transmitting on the gate lead wire.

Therefore, in accordance with the reduction of the resistance of the gate lead wire, it is possible to further reduce the size of one and the other mounting portion of the gate lead wire. As a result, it is possible to reduce the cost of the gate lead wire, and it is also possible to set the fixing area between the one mounting portion of the gate lead wire and the center gate electrode to be small.
This fixing work can be facilitated and costs can be reduced,
As a result, the reliability of this fixed portion can be dramatically improved.

According to an eighth aspect of the present invention, there is provided a semiconductor element in which a plurality of segments are formed in a ring shape from a central axis side thereof to a side surface side thereof, and a central position of one main surface of the semiconductor substrate. From a part of the outer peripheral surface of the center electrode to the center position, a center electrode having a predetermined diameter and a predetermined thickness, which is contacted and arranged on the one main surface toward the outer peripheral side of the main surface. A groove formed in the center electrode itself, and fixed to the center electrode on the inner surface of the groove at the center position and contacting the inside of the groove to the outside of the outer peripheral surface of the center electrode. It is provided with a metal lead wire, and the relationship of (width of the groove)> (width of the lead wire) and (depth of the groove)> (thickness of the lead wire) is established. To do.

As a result, the same operation as in claims 1 and 2
It is effective.

A semiconductor element according to a ninth aspect of the present invention is the semiconductor element according to the eighth aspect, wherein a part of the lead wire is fixed to the inner surface of the groove portion at the central position and is provided in the groove portion. It is formed so that the cross-sectional area is the same and the surface area per unit length is larger than that of the arranged portion.

As a result, the same action and effect as the third aspect can be obtained.

[0033]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention denies the configuration of a conventional center gate type gate portion based on the same idea as that of a peripheral gate type semiconductor element. That is, a groove is formed in the center gate electrode itself from a part of the outer peripheral surface of the center gate electrode to the central position of the semiconductor substrate or the central position of its main surface, and only on the inner surface of the groove at the central position. , Attach the metal gate lead wire attachment part to the center gate electrode. In this case, (groove width)> (gate lead width) and (groove depth)>
The groove is formed so that the relationship of (thickness of gate lead wire) is established. Then, the portion of the gate lead wire excluding the attachment portion is formed so as to have the same cross-sectional area and a larger surface area per unit length as compared with the attachment portion. Specifically, it is as follows.

Here, as an example, a case where a gate turn-off (GTO) thyristor is used as a semiconductor element will be described. Of course, instead of the GTO thyristor, a bipolar transistor having a three-layer structure or an IGBT can be used as a semiconductor element. In the case of an IGBT or npn transistor, the emitter is the first electrode and the collector is the second electrode.
It corresponds to an electrode. However, the base of the bipolar transistor corresponds to the center gate electrode here.

(Embodiment 1) FIG. 1 is a sectional view showing the structure of a pressure contact type semiconductor device 20. In FIG. 1, reference numeral 11 is a cathode electrode (first electrode) having a cylindrical shape with a diameter of 2R, 12 is the same shape as the cathode electrode 11, an anode electrode (second electrode) having the same size, and 14 is a center gate. A ring-shaped cathode heat compensating plate (first heat compensating plate) 13 disposed on a predetermined portion of one main surface (first main surface) 27 of the semiconductor substrate, excluding the contact portion with the electrode, is a semiconductor. A disk-shaped anode heat compensating plate (second heat compensating plate) entirely arranged on the other main surface (second main surface) 28 of the substrate,
Reference numeral 8 denotes a cylindrical semiconductor substrate having a diameter of 2R, which is pressed against each of the electrodes 11 and 12 through each of the thermal compensating plates 14 and 13, and 16 has a center position of the central axis 31 of the semiconductor substrate 1. A center gate electrode 17 having an XY cross section forming a circle having a radius r, which is in contact with and placed on one main surface 27 of the main surface 27 so as to be on the same position as the center of one main surface 27 of the substrate 1, , A gate lead wire for transmitting a gate signal (here, a gate current) inputted from the outside, 15 is
It is an insulating cylinder having a flange 29 and fixed to the cathode electrode 14 and the anode electrode 12 via the flange 29. The semiconductor element (GTO element) of the press-contact type semiconductor device 20 is hermetically sealed by the insulating cylinder 15.

Further, 40 is a molded body made of silicone rubber or the like for passivation. The side surface portion 18S of the semiconductor substrate 18 is fitted into the molded body 40.

The semiconductor substrate 18 is, for example, a silicon wafer as a base material, and has a plurality of GTO thyristor segments formed in a ring shape from the central axis 31 side toward the outer peripheral surface or the side surface portion 18S side. doing. Therefore, in order to show the structure of these segments, the vertical cross-section (YZ plane) structure of the semiconductor substrate 18 is schematically shown in FIG.

As shown in the figure, the substrate 18 has a p-layer 34, an n-layer 35, a p-layer 36 and an n-layer 38 which are sequentially laminated. Then, on the exposed surface of the p layer 36, the center gate layer 37 corresponding to the center gate electrode 16 is formed.
Is formed, and its central axis coincides with the central axis 31. Further, the cathode layer 32 is also formed on the surface of each n layer 38. Furthermore, on the back surface of the p layer 34,
The anode layer 33 is formed on the entire surface. The center gate layer 37 is in electrical contact with the center gate electrode 16, and each cathode layer 32 is connected to the cathode electrode 1.
1 is pressed against one main surface 27 of the semiconductor substrate 18 via the cathode heat compensating plate 14 in response to the application of an external force, and is electrically connected to the cathode electrode 11 via the plate 14. Further, the anode layer 33 is also electrically connected to the anode electrode 12 via the anode heat compensating plate 13 and the other main surface 28 by pressure contact with the anode layer 33 according to the external force application. It Therefore, one main surface 27 is formed by the exposed upper surfaces of the gate layer 37 and each cathode layer 32, and the other main surface 28 substantially parallel to the one main surface 27 is the exposed lower surface of the anode layer 32. It can be said that it is formed by the surface.

Reference numeral 36 indicates each segment formed in a ring shape from the central axis 31 side to the outer peripheral surface 18S side at predetermined intervals.

Next, the structure of the center gate electrode 16 will be described in detail. FIG. 3 is a perspective view showing only the center gate electrode 16, and the gate lead wire 17 is shown in FIG.
It corresponds to the state before it is attached to. As shown in the figure, the center gate electrode 16 is a metal body having a height H or a height H, and its center position O corresponds to the center position of one main surface 27.

In the center gate electrode 16 itself, a groove 30 extends from a part of the cylindrical side surface 25 excluding the side surface 25S obliquely inclined to the center position O of the electrode 16.
Are formed. The groove portion 30 is a groove having a width W, a depth D, and a length L, and has the inner surface S1 at the center position O and the other three.
It consists of two inner surfaces S2 to S4. Each inner surface S1 to S3 is
It intersects substantially perpendicularly to the inner surface S4 that is the bottom surface. Reference code 2
6 is the outer circumference.

The dimensions of the groove 30 are the same as those of the gate lead wire 17.
It is set so as to satisfy the following condition in relation to the size of the one mounting portion 19. That is, if the width and the thickness of the one mounting portion 19 are described as W0 and D0, respectively (see FIGS. 4 and 5), the relationship of W> W0 and D> D0 is established. By setting this condition relationship, as will be described later, in one of the attachment portions 19 of the gate lead wire 17,
Only one end portion 41 (see FIG. 5) consisting of one end thereof and a portion necessary for fixing the periphery thereof is fixed to the center gate electrode 16, and the other portion of the one mounting portion 19 is fixed to the groove portion 3
0 in the non-contact state with any of the other inner surfaces S2 to S4,
Moreover, it is possible to dispose the one mounting portion 19 in the groove portion 30 so that the one mounting portion 19 is completely included in the groove portion 30. Of course, even if the above condition is not satisfied, it may be possible to dispose one of the mounting portions in such a non-contact manner. Since it protrudes in the Z direction, such an example is not preferable in terms of application to a pressure contact type semiconductor device.

Next, the structure of the gate lead wire 17 and its mounting method or structure on the center gate electrode 16 will be described. 4 and 5 are diagrams in which the center gate electrode 16 and the gate lead wire 17 are extracted and drawn, and correspond to a side view and a plan view, respectively.

In both figures, the gate lead wire 17 is composed of three parts, one mounting part 19, a lead part 22 and the other mounting part 21. One mounting portion 19
Is a portion of which a portion (a portion corresponding to the length L) is disposed in the groove portion 30 and which is fixed and supported by the center gate electrode 16, and the other attaching portion 21 is the insulating cylinder 15
This is a part that is fixedly supported in a through hole 43 provided inside. Here, both attachment parts 19 and 2
1 has the same shape and the same size.

On the other hand, one end of the lead portion 22 has the groove portion 3
0 is connected to the other end of one mounting portion 19 protruding from the cut end of the outer peripheral surface 25 and the other end is the other mounting portion 2
It is a connecting part that is connected to 1. And the lead portion 2
Only 2 is previously formed into a thin flat plate shape by rolling. Here, the rolling direction is the normal direction of the one main surface 27, that is, the Z direction. By setting the rolling direction in the Z direction, it is possible to set the width of the groove portion provided on the back surface 11S side of the cathode electrode 11 to be described later to be small. The length, width and thickness of the lead portion 22 are
L1, W1 and D1, respectively, and the relationship of W1 << W0 and D1 >> D0 is established.

As the material of the gate lead wire 17, it is necessary to use a reliable metal body having a low resistivity.
As one of such suitable materials, Ag is used here as the gate lead wire 17.

As the shape of the gate lead wire 17 before rolling, various shapes can be used, but for example, a square bar or a round bar may be used.
Here, a round bar having a diameter φ is used as a base material of the gate lead wire 17. Therefore, in the case of using the round bar, the one and the other mounting portions 19 and 21 are both lengths L0 and XZ.
The cross-sectional shape becomes a circular cylinder with a diameter of φ, and the width W
0 and the thickness D0 are both equal to the diameter φ of the round bar (W0 = D0 = φ). When using a square bar, the shapes of both attachment parts 19 and 21 are width W0, thickness D0, and length L.
It becomes a rectangular parallelepiped shape.

Although not shown in FIG. 1, FIG.
Then, as shown in the figure, the entire surface of the lead portion 22 is covered with the tube 23.

As described above, since only the lead portion 22 of the gate lead wire 17 is formed by rolling in the Z direction, the cross-sectional area of the XZ cross section of the lead portion 22 is determined by the two mounting portions 19, 2.
It is possible to set the surface area per unit length of the lead portion 22 to be sufficiently larger than those of both attachment portions 19 and 21, while maintaining the same XZ sectional area of 1. For example, when using the conventional structure, the length of the portion corresponding to the lead portion 22 is 33.5 mm and the diameter φ is 2.5 mm.
Then, the surface area is 263 mm ² , but here, the length L1 of the lead portion 22 is 33.5 mm, the width W1 is 1.0 mm, and the thickness D1 is 5.3 mm. Therefore, the surface area is 442 mm ² . It is set. As a result, when a gate signal, that is, a gate current is input to the gate lead wire 17 from the outside, a so-called skin effect occurs in the lead portion 22 having a remarkably increased surface area, which increases the transmission amount of the gate signal, The amount of attenuation of the gate signal will be sufficiently suppressed. Thus, by processing the gate lead wire 17 in a shape that increases the surface area without changing the cross-sectional area, the resistance or impedance of the gate lead wire 17 can be sufficiently reduced. For example, in the case of the above dimension example, in the conventional case, the resistivity is 2.
Although it was 0 mΩ, in this example, the resistivity can be reduced to 1.4 mΩ. The improvement rate has reached 30%.

The lowering of the impedance due to the skin effect is caused by the simultaneous installation of both mounting portions 19 of the gate lead wire 17,
It is possible to reduce the size of the XZ sectional shape of 21, that is, in this example, to reduce the diameter φ of the round bar.
The reduction of the diameter φ makes a great contribution to the fixation of both mounting portions 19 and 21 described below.

By adopting such a structure of the gate lead wire 17, it was conventionally necessary to use a round bar having a diameter φ of 3.0 mm or more as the gate lead wire. For example, the diameter φ is 2.5 mm. It has become practically possible to use a round bar as a base material for the gate lead wire 17. The minimization of the diameter φ brings about an effect of reducing the cost of the gate lead wire 17 itself.

Next, the mounting of the one mounting portion 19 and the center gate electrode 16 will be described in detail. As illustrated in FIGS. 4 and 5, the tip or one end 44 of the one mounting portion 19 is positioned only within the inner surface S1 of the groove portion 30 and does not protrude from the inner surface S1.
It is fixed by brazing. Therefore, the fixed portion or the brazing portion 24 actually spreads not only on the inner surface S1 but also in the vicinity of the intersection of the inner surfaces S2 and S3 with the inner surface S1. In that sense, the one mounting portion 19 has one end portion 4
In No. 1, it can be said that it is fixed to the center gate electrode 16.

Moreover, when positioning and brazing the one mounting portion 19, the surface excluding the one end portion 41 does not come into contact with any of the other inner surfaces S2 to S4 except the fixing portion 24, and the inner surfaces of the mounting portions 19 are not contacted. It is disposed in the groove 30 substantially parallel to S2 to S4. Therefore, the one mounting portion 19 does not protrude from the groove portion 30 in the + Z direction (upward direction). Moreover, since D1 <D is set, the lead wire 17 does not hinder the pressure contact of the cathode electrode 11.

As described above, in this structure, since the gate lead wire 17 is attached almost only at the center position O of the center gate electrode 16, a turn-off signal as a gate signal is supplied to the gate lead wire 17 from an external source. For example, when input from the gate driver, the gate signal is input into the semiconductor substrate 18 from the center position O of the center gate electrode 16 and is centered in the semiconductor substrate 18 (specifically, the p layer 36 in FIG. 2). The outer peripheral surface 18S from the shaft 31 side
It will be uniformly and radially transmitted toward the side. As a result, concentration of the gate signal does not occur, the gate signal is uniformly input to each of the segments 36 around the gate layer 37, and each segment is efficiently turned on. That is, the turn-on time of each segment is drastically shortened, and their electrical characteristics, especially the turn-on current allowable value, are significantly improved as compared with the prior art.
For example, with this configuration, the increase rate of the critical on-current is improved by about 25% as compared with the conventional case.

The above effects are schematically illustrated in FIGS. 6 and 7. FIG. 6 is a plan view of the semiconductor substrate 18 showing a gate signal transmission state according to the present invention, and FIG. 7 is a plan view showing a gate signal transmission state according to a conventional technique.

In the fixing structure as described above,
The size of the gate lead wire, and therefore one mounting part 19
By using the main gate lead wire 17 (FIGS. 4 and 5) in which both dimensions W0 and D0 are set smaller than in the conventional case, the area area or region of the fixing portion 24 is also reduced, and the brazing work is remarkably easy. And the reliability of brazing is increased.

Conversely, in order to improve the electrical characteristics,
It is essential to form the groove 30 in the center gate electrode 16 and fix the gate lead wire 17 only on the inner surface S1 at the center position. At this time, it is necessary to reduce the size of the groove portion 30 and improve the reliability of the brazing portion. However, the conventional specifications (FIGS. 10 and 11) cannot satisfy the above requirements with the gate lead wire 7. Therefore, it is essential to adopt the gate lead wire 17 of FIGS. By adopting this, it is possible to meet the above-mentioned demand for miniaturization while reducing the impedance to a required value by utilizing the skin effect.

In addition, the shape of the other mounting portion 21 is set smaller than that of the conventional one (for example, φ = 2.5 m).
m), also when brazing the portion 21 and the through hole 43,
Similar effects can be obtained.

In addition, the adoption of this gate lead wire 17
As illustrated in the plan view of FIG. 8, on the back surface 11S (FIG. 1) of the cathode electrode 11, the center gate electrode 16,
The width or diameter WA of a groove or notch (corresponding to another groove) 45 formed for allowing the cathode electrode 16 to be pressure-contacted without being brought into contact with one of the mounting portion 19 and the lead portion 22 is smaller than that of the conventional one. This brings the advantage that it can be set to a small value. For example, conventionally, the dimension WA is φ3.0 mm
In contrast to this, the dimension WA can be reduced to a value slightly larger than φ2.5 mm in the present invention.

As a result, the processing cost of the cathode electrode 11 is reduced, and the surface area of the back surface 11S of the cathode electrode 11 is increased.
It is possible to increase the contact area between the electrode 11 and the one main surface 27 via the electrode 4.

By simply fixing the above-mentioned gate lead wire 17 to the outer peripheral surface of the conventional center gate electrode 6 (FIGS. 9 to 11), the impedance can be reduced and the size of one mounting portion 19 of the gate lead wire 17 can be reduced. It is possible to achieve various effects such as reduction of the cost, facilitation of brazing, improvement of reliability, and reduction of base material cost of the gate lead wire.

Although the processing cost increases due to the rolling process of the lead portion 22, the gate lead wire 17 is further increased.
The cost of reducing the base material is larger, and when viewed as a whole, adopting the gate lead wire 17 of the present invention is
It is cost effective.

(Summary) In this pressure contact type semiconductor device 20, the gate lead wire 17 is attached to the mounting portions 19 and 21 at both ends.
And a lead portion 22 in the center,
By changing only the shape of 2 under the idea of expanding the surface area per unit length while having the same cross-sectional area,
When the gate signal is transmitted to the semiconductor substrate 18, it is possible to reduce the impedance component generated in the gate lead wire 17 by the skin effect, so that the attenuation of the gate signal can be suppressed.

Further, since the impedance can be reduced without increasing the thickness of the gate lead wire 17, it is possible to promote the reduction of the shape and size of the gate lead wire 17, and moreover, only one end portion of the mounting portion 19 thereof. Is arranged substantially in the center of the center gate electrode 16, the gate signal can be uniformly transmitted from the center of the semiconductor substrate 18 to each segment while achieving reliability and cost reduction of the fixing portion of the mounting portion. The electrical characteristics of the device can be remarkably improved.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing a pressure contact type semiconductor device according to a first embodiment of the present invention.

FIG. 2 is a vertical cross-sectional view showing a segment formed on a semiconductor substrate.

FIG. 3 is a perspective view showing a structure of a center gate electrode.

FIG. 4 is a side view of a gate portion.

FIG. 5 is a plan view of a gate portion.

FIG. 6 is a plan view schematically showing transmission of a gate signal in a semiconductor substrate.

FIG. 7 is a plan view schematically showing transmission of a conventional gate signal in a semiconductor substrate.

FIG. 8 is a plan view schematically showing a groove portion formed in a cathode electrode.

FIG. 9 is a vertical sectional view showing a conventional pressure contact type semiconductor device.

FIG. 10 is a side view of the gate portion provided in FIG.

FIG. 11 is a plan view of a conventional gate portion.

[Explanation of symbols]

11 cathode, 12 anode electrode, 13 anode heat compensator, 14 cathode heat compensator, 15 insulating tube, 1
6 Center gate electrode, 17 Gate lead wire, 18
Semiconductor substrate, 19 One mounting part, 21 Other mounting part, 22 Lead part, 27 One main surface, 28
The other main surface, 30 grooves, S1 inner surface.

Claims (9)

[Claims] 1. A semiconductor substrate having a plurality of segments formed in a ring shape from its central axis side toward its side surface side, and its center position is aligned with the center position of one main surface of the semiconductor substrate. A center gate electrode contacting and arranged on the one main surface, and formed on the center gate electrode itself from a part of an outer peripheral surface of the center gate electrode to the center position of the center gate electrode. One end of the groove portion and the one mounting portion on the inner surface of the groove portion at the center position of the center gate electrode is fixed to the center gate electrode to control the on / off operation of the segment. A gate lead wire for transmitting a gate signal from the outside to the center gate electrode, the one of the gate lead wires excluding the one end portion. Mounting portion, without contacting the other of the inner surface of the groove, the groove portion is disposed outward of the outer peripheral surface,
Pressure contact type semiconductor device. 2. The pressure contact type semiconductor device according to claim 1, wherein the width and the depth of the groove are set to be larger than the width and the thickness of the gate lead wire, respectively. 3. The pressure contact type semiconductor device according to claim 1, wherein the gate lead wire is provided on the one mounting portion whose other end protrudes from the groove and the other end of the one mounting portion. It has a lead part having one end connected to it, and another end part having the same shape and the same size as the one attachment part connected to the other end of the lead part, and only the lead part is formed by rolling. Pressure contact type semiconductor device. 4. The pressure-contact type semiconductor device according to claim 3, wherein the rolling direction of the lead portion is set in a direction normal to the one main surface of the semiconductor substrate. 5. The pressure contact type semiconductor device according to claim 4, wherein a first heat compensating plate is provided on a predetermined portion of the one main surface excluding a portion where the center gate electrode is formed, and the first heat compensating plate. It further comprises a first electrode that press-contacts the one main surface of the semiconductor substrate via a compensating plate, and the center gate electrode and the center gate electrode are provided on the back surface side of the first electrode facing the first heat compensating plate. A pressure contact type semiconductor device, in which another groove portion whose shape and dimensions are set so as not to contact the one mounting portion and the lead portion is formed. 6. The pressure contact type semiconductor device according to claim 5, wherein a second heat compensating plate is disposed on the other main surface of the semiconductor substrate, and the semiconductor substrate is provided with the second heat compensating plate interposed therebetween. It further comprises a second electrode that press-contacts the other main surface, and an insulating cylinder fixed to each side surface of the first electrode and the second electrode, wherein the other mounting portion of the gate lead wire is the insulating cylinder. A pressure contact type semiconductor device fixed to the. 7. A semiconductor substrate in which a plurality of segments are formed in a ring shape from the central axis side toward the side surface side thereof, and the center position of the segment matches the center position of one main surface of the semiconductor substrate. A center gate electrode that is in contact with and disposed on the one main surface, one and the other attachment portions, and a lead portion that connects the one and the other attachment portions, and one end of the one attachment portion Part is fixed to the center gate electrode,
In addition, a gate lead wire for transmitting a gate signal for controlling the ON and OFF operations of the segment to the center gate electrode, and only the lead portion of the gate lead wire is formed by rolling. apparatus. 8. A semiconductor substrate having a plurality of segments formed in a ring shape from its central axis side toward its side surface side, and from the central position of one main surface of the semiconductor substrate toward the outer peripheral side of the main surface. Contacted and arranged on the one main surface,
A center electrode having a predetermined diameter and a predetermined thickness, a groove portion formed in the center electrode itself from a part of the outer peripheral surface of the center electrode to the center position, and the groove portion at the center position. A lead wire of a metal body, which is fixed to the center electrode on the inner surface and is arranged in the groove portion in a non-contact manner to the outside of the outer peripheral surface of the center electrode, and (width of the groove portion)> ( A semiconductor element in which the relationship of (width of lead wire) and (depth of groove portion)> (thickness of lead wire) is established. 9. The semiconductor element according to claim 8, wherein a part of the lead wire is fixed to the inner surface of the groove portion at the central position and is provided in the groove portion as compared with a portion thereof. A semiconductor device having the same cross-sectional area and having a large surface area per unit length.