JPH0685109A - Tape carrier type semiconductor device and its assembly method - Google Patents

Abstract

PURPOSE:To provide a semiconductor device the substrate of which can be secured by a sufficient adhesion strength and which can obtain a high reliability by a simple working and its assembly method. CONSTITUTION:A cylindrical insulation member 18 is coupled with an anode electrode plate 4 to form a space by the cylindrical insulation member 18, the anode electrode plate 4, and a semiconductor substrate 2. The space is filled with silicon rubber 20. Therefore, the semiconductor substrate 2 is secured to not only the anode electrode plate 4, but also the cylindrical insulation member 18, so that the adhesion strength of the semiconductor substrate 2 is improved. A predetermined space is regulated to limit the filling range of the silicon rubber 20 by engaging the cylindrical insulation member 18 and the anode electrode plate 4, so that no extra silicon rubber flows out, dispensing with its removal work. As a result, contamination with silicon rubber 20 can be prevented, and a high reliability semiconductor device can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a full pressure contact type semiconductor device in which a main electrode is brought into electrical contact with a semiconductor substrate having at least one PN junction by pressure contact, and an assembling method thereof.

[0002]

2. Description of the Related Art In a full pressure contact type semiconductor device, for example, FIG.
As shown in FIG. 9 and FIG. 30, an anode metallization layer 12 formed by vapor-depositing a metal is formed as an anode electrode on the upper main surface of the semiconductor substrate 2, and a gate electrode as a gate electrode is formed at the center of the lower main surface. A cathode metallization layer 16 as a cathode electrode is formed on the gate metallization layer 14 and its peripheral region by vapor-depositing a metal similarly to the anode metallization layer 12. The outer peripheral edge of the semiconductor base 2 and the outer peripheral edge of the anode electrode plate 4 are covered with the silicone rubber 20 to protect the outer peripheral edge of the semiconductor base 2, and the semiconductor base 2 functions as a fixing electrode plate. The anode electrode plate 4 is positioned and fixed.

The semiconductor substrate 2 thus fixed to the anode electrode plate 4 is fitted in a casing (not shown) together with other members such as a cathode electrode plate. The casing is formed so that its inner diameter is substantially equal to the outer diameter of the anode electrode plate 4. Therefore, the semiconductor substrate 2
When the above is housed in the casing, the outer peripheral portion of the anode electrode plate 4 conforms to the inner peripheral surface of the casing, and the semiconductor substrate 2 is positioned in the substantially central portion of the casing.

[0004]

By the way, since the same voltage as the voltage applied to the semiconductor device is applied between the cathode metallization layer 16 and the anode electrode plate 4, it depends on the withstand voltage characteristics of the semiconductor device. It is necessary to set the creepage distance of the silicone rubber 20. Here, "creeping distance" means
This is the distance connecting the upper surface side and the lower surface side of the semiconductor substrate 2 along the surface of the insulating material. For example, in FIG. 30, the distance of the route along the points PA, PB, and PC corresponds to this. The longer the creepage distance, the longer the electrical distance between the upper main surface and the lower main surface of the semiconductor substrate 2, and the phenomenon such as a short circuit is less likely to occur. Therefore, in order to increase the creepage distance of the silicone rubber 20, the coating amount of the silicone rubber 20 may be increased.

In the above case, for example, as shown in FIG. 29, the silicon rubber 20 may flow to the outer peripheral side surface and the back surface side of the anode electrode plate 4, but since the semiconductor substrate 2 is fitted into the casing. Need to remove these excess silicone rubber. Therefore, conventionally, two molding methods have been proposed. First, as the first method,
After the silicon rubber 20 is applied so as to cover the outer peripheral portion of the semiconductor substrate 2 and the outer peripheral portion of the anode electrode plate 4 and further solidified, excess silicon is applied along the outer shape of the anode electrode plate 4 as shown in FIG. There is a method of mechanically removing the rubbers 20a and 20b and molding the silicon rubber 20c into a desired shape. As a second method, a molding jig is arranged in advance along the outer shape of the anode electrode plate 4, and the silicone rubber 20 is applied to the space defined by the molding jig, the semiconductor substrate 2 and the anode electrode plate 4. After solidification, there is a method of removing the molding jig.

However, whichever method is adopted, the withstand voltage characteristic of the semiconductor device becomes unstable due to the contamination from the removing jigs of the silicon rubbers 20a and 20b and the molding device, and the reliability of the semiconductor device is deteriorated. For example, when a machine tool such as a lathe is used to remove the silicone rubbers 20a and 20b, oil and ionic substances (such as Na ions in salt contained in indoor water) are mixed into the silicone rubber 20 and 20 hinders the insulating property and the like. In addition to the problem that the reliability of the semiconductor device is lowered, there is a problem that the number of manufacturing processes is increased.

Further, as described above, since the semiconductor substrate 2 is bonded to the anode electrode plate 4 by the silicon rubber 20, when the difference in the outer dimensions of the semiconductor substrate 2 and the anode electrode plate 4 becomes small, Anode electrode plate 4
The adhesive strength with will decrease. In particular, when a planar type (PN junction is exposed on the main surface of the semiconductor substrate) semiconductor element is formed on the semiconductor substrate 2, a guard ring is formed on the outer peripheral portion of the cathode region in order to obtain a high breakdown voltage. It is often necessary to make the outer shape of the semiconductor substrate 2 larger than that in the case of forming a mesa type semiconductor element in which the PN junction is exposed at the outer peripheral side surface portion of the semiconductor substrate 2 in many cases. As a result, the difference in external dimensions between the semiconductor substrate 2 and the anode electrode plate 4 becomes smaller, and the decrease in adhesive strength becomes a significant problem.

The present invention solves the above problems,
It is an object of the present invention to provide a semiconductor device in which a semiconductor substrate is fixed with sufficient adhesive strength, and yet high reliability can be obtained by a simple operation, and an assembling method thereof.

[0009]

In order to achieve the above object, the invention of claim 1 is a semiconductor substrate, a first metallization layer provided on one main surface of the semiconductor substrate, and the semiconductor substrate. A second metallization layer provided on the other principal surface of the first electrode plate, a first electrode plate whose one surface is in contact with the first metallization layer, and an external dimension larger than that of the first electrode plate, Moreover, the cylindrical insulating member includes a second electrode plate whose one main surface is in contact with the second metallized layer, and a substantially cylindrical insulating member that fits the outer peripheral portion of the second electrode. Is coupled to the second electrode, a space is formed by the tubular insulating member, the second electrode plate and the semiconductor substrate, and the space is filled with an insulating adhesive member, The outer periphery of the semiconductor substrate is the insulating adhesive member. At least the at protection state second
It is fixed to the electrode plate and the tubular insulating member.

According to a second aspect of the present invention, a cutout portion is provided in the outer peripheral portion of the second electrode plate on the one main surface side.

According to a third aspect of the present invention, one end of the tubular insulating member is locked by the cutout portion of the second electrode plate.

According to a fourth aspect of the present invention, a locking portion is provided so as to project inward from an inner peripheral surface on one end side of the tubular insulating member,
The locking portion is locked to the other main surface of the second electrode plate in a state where the tubular insulating member is coupled to the second electrode.

According to a fifth aspect of the present invention, a through hole is provided in the outer peripheral portion of the second electrode plate, and the space portion communicates with the other main surface side of the second electrode plate by the through hole.

According to a sixth aspect of the present invention, a closed loop groove is provided in a contact region of the one main surface of the second electrode plate which is in contact with the second metallization layer.

According to a seventh aspect of the present invention, at least one closed loop groove is further provided in the contact area.

According to an eighth aspect of the present invention, a through hole is provided in the second electrode plate corresponding to the groove, and the groove communicates with the other main surface side of the second electrode plate by the through hole. There is.

According to a ninth aspect of the present invention, the outer dimensions of a second contact area of the one main surface of the second electrode plate, which is in contact with the second metallized layer, are defined as one main surface of the first electrode plate. Of the first contact area of the first metallization layer, which is larger than the contact area of the first metallization layer, and when the first contact area is projected onto one main surface of the second electrode plate, the projected area is It is located within the contact area of 2.

According to a tenth aspect of the present invention, the external dimensions of the semiconductor substrate are smaller than the external dimensions of the second electrode plate and the internal dimensions of the tubular insulating member, and a PN junction is provided on the semiconductor substrate. A part of the PN junction is exposed at the outer peripheral end of the semiconductor substrate.

According to the invention of claim 11, the semiconductor substrate is made of P
The N-junction is provided so as to be exposed on the one main surface of the semiconductor substrate, and the external dimensions of the semiconductor substrate are substantially equal to the external dimensions of the second electrode plate.

According to a twelfth aspect of the present invention, the semiconductor substrate is made of P.
The N-junction is provided so as to be exposed on both main surfaces of the semiconductor substrate, and the exposed region on the other main surface side of the semiconductor substrate is opposed to the cutout portion of the second electrode plate.

According to a thirteenth aspect of the present invention, the semiconductor substrate is made of P.
An exposed region is formed by providing the N junction so as to be exposed on at least one main surface of the semiconductor substrate, and a ring-shaped electric field relaxation region is further provided on the outer peripheral portion of the exposed region, and the electric field relaxation region is provided. A metal film connected to a part of the metal film is formed, and the insulating adhesive member covers the metal film.

According to a fourteenth aspect of the present invention, there is provided a method for assembling a semiconductor device, comprising a semiconductor substrate having electrode layers formed on both main surfaces thereof, sandwiched between first and second electrode plates. To this end, (a) a step of preparing a casing having two facing openings, and (b) a step of fixing the semiconductor substrate to the second electrode plate and the substantially tubular insulating member, A locking member is provided on the cylindrical insulating member so as to project inwardly from the inner peripheral surface on one end side thereof, and the second electrode can be fitted into the cylindrical insulating member (b-
1) A step of placing the tubular insulating member so that the other end side thereof faces upward, and fitting the second electrode plate into the tubular insulating member; and (b-2) fitting into the tubular insulating member. State, placing the semiconductor substrate at a predetermined position on the upper surface of the second electrode plate, and (b-3) the inner peripheral surface of the tubular insulating member, the upper surface of the second electrode plate, and the A step of filling an insulating adhesive member in a space formed at the outer peripheral end of the semiconductor substrate; and (b-4) solidifying the insulating adhesive member so that the semiconductor substrate has the cylindrical insulating member and the cylindrical insulating member. Obtaining a combination fixed to the second electrode plate,
A step of fixing the semiconductor substrate including (c) the combination, the first electrode plate, and the first and second external electrodes, wherein the first electrode plate is the second electrode plate of the semiconductor substrate. While contacting the main surface on the opposite side, the first and second external electrodes contact the outer main surfaces of the first electrode plate and the second electrode plate, respectively, and their main surfaces are And (d) storing the first external electrode and the second external electrode so as to be parallel to the opening of the casing.
Fixing external electrodes to the respective ends of the openings of the casing.

According to a fifteenth aspect of the present invention, there is provided a method for assembling a semiconductor device, comprising a semiconductor substrate having electrode layers formed on both main surfaces thereof, sandwiched between first and second electrode plates. In order to: (a) prepare a casing having two facing openings; and (b) fix the semiconductor substrate to the second electrode plate and the substantially cylindrical insulating member, The cylindrical insulating member has a shape in which one end thereof fits the outer peripheral portion of the second electrode plate, and
1) A step of closing the opening on the one end side of the tubular insulating member with the second electrode plate in a state where the other end side of the tubular insulating member is facing upward, (b-2) Placing the semiconductor substrate at a predetermined position on the upper surface of the second electrode plate, (b-3) an inner peripheral surface of the tubular insulating member,
Filling the space formed by the upper surface of the second electrode plate and the outer peripheral end of the semiconductor substrate with an insulating adhesive member, and (b-4) solidifying the insulating adhesive member A step of obtaining a combined body in which a semiconductor body is fixed to the tubular insulating member and the second electrode plate; and a step of fixing the semiconductor body including (c) the combined body, the first
The electrode plate and the first and second external electrodes, the first electrode plate is in contact with the main surface of the semiconductor substrate opposite to the second electrode plate, and the first and second external electrodes. The external electrode is housed in the casing such that the external electrodes are in contact with the outer main surfaces of the first electrode plate and the second electrode plate and the main surfaces are parallel to the opening of the casing. And (d) fixing the first external electrode and the second external electrode to the respective end portions of the opening of the casing.

Further, in the method of claim 16, (a)
A step of preparing a casing having two facing openings, and (b) the first and second semiconductor substrates.
Of the electrode plate and the substantially cylindrical insulating member, the cylindrical insulating member has a shape in which one end thereof fits the outer peripheral portion of the second electrode plate, (b- 1) A step of closing the opening on the one end side of the tubular insulating member with the second electrode plate in a state where the other end side of the tubular insulating member is facing upward, (b-2) Placing the semiconductor substrate at a predetermined position on the upper surface of the second electrode plate, (b-3) placing the second electrode plate on the semiconductor substrate, (b-4) Filling the space formed by the inner peripheral surface of the tubular insulating member, the upper surface of the second electrode plate, the outer peripheral end of the semiconductor substrate, and the side surface of the first electrode plate with an insulating adhesive member. And (b-5) by solidifying the insulating adhesive member, the semiconductor substrate is The step of fixing the semiconductor substrate, which includes the step of obtaining a combined body fixed to the first and second electrode plates, and (c) the combined body and the first and second external electrodes, The second outer electrode is in contact with the outer main surfaces of the first electrode plate and the second electrode plate, and the main surfaces are parallel to the opening of the casing. The process of storing inside
(D) fixing the first external electrode and the second external electrode to the ends of the openings of the casing.

[0025]

According to the present invention, the cylindrical insulating member is coupled to the second electrode, and the cylindrical insulating member, the second electrode plate and the semiconductor substrate form a space. By filling the space with an insulating adhesive member, the semiconductor substrate is fixed not only to the second electrode plate but also to the tubular insulating member, and the adhesive strength of the semiconductor substrate is improved. Further, a predetermined space portion is defined by connecting the tubular insulating member with the second electrode,
Since the filling range of the insulative adhesive member is limited, the excess insulative adhesive member does not flow out, and the removal work thereof is unnecessary. As a result, contamination of the insulating adhesive member is prevented, and a highly reliable semiconductor device can be obtained.

According to the fourteenth, fifteenth and sixteenth aspects of the present invention, the semiconductor device having the above structure can be properly assembled.

[0027]

EXAMPLES A. First Embodiment FIG. 1 is a vertical sectional view showing a first embodiment of the semiconductor device according to the present invention. As shown in the figure, this pressure contact type semiconductor device has a semiconductor substrate 2, an anode electrode plate 4, a cathode electrode plate 6, an external anode electrode 8 and an external cathode electrode 10, and the like, and is used as an external device. In the assembled state, the semiconductor substrate 2 is pressed and sandwiched via the external anode electrode 8 and the external cathode electrode 10 by the pressure applied from the external device.

The semiconductor substrate 2 is made of, for example, a silicon substrate and has at least one PN junction. For example, as shown in FIG. 2, a mesa type thyristor is formed on the semiconductor substrate 2. That is, the semiconductor substrate 2
P emitter layer PE and P base layer PB are formed on the upper and lower main surfaces of the P emitter layer PE and P emitter layer PE, respectively.
And the N base layer NB is formed between the P base layer PB and the P base layer PB. In addition, the N emitter layer NE is formed on a part of the P base layer PB.
Is provided. In this mesa type thyristor, as shown in the figure, since the PN junction is exposed on the side surface of the outer peripheral portion 2c of the semiconductor substrate 2, it is especially important to prevent the side surface from being contaminated.

A metal such as aluminum is vapor-deposited on a part of the upper main surface 2a of the semiconductor substrate 2 to form an anode metallized layer 12 functioning as an anode electrode. On the other hand, a gate metallization layer 14 as a gate electrode is formed in the central portion of the lower main surface 2b, and a cathode metallization layer 16 as a cathode electrode is formed in the peripheral region in the same manner as the anode metallization layer 12. .

The anode electrode plate 4 is substantially disc-shaped, and its diameter is larger than that of the semiconductor substrate 2 and smaller than the inner diameter of a cylindrical casing 28 made of ceramic. Further, on the lower main surface of the anode electrode plate 4, a ring-shaped cutout portion 4a which is concentric with the outer periphery thereof (FIG. 2).
Are formed.

A heat-resistant insulating member 18 having a substantially tubular shape (hereinafter referred to as "cylindrical insulating member") 18 is fitted in the anode electrode plate 4, and the tubular insulating member 18 is preferably made of ceramic. FIG. 3 shows the cylindrical insulating member 1
9 is a perspective view of FIG. As shown in the figure, the locking portion 1 is inwardly extended from one end of the side surface portion 18c of the tubular insulating member 18.
8b is projected. Therefore, when the anode electrode plate 4 is fitted from the other end side of the tubular insulating member 18, the locking portion 18b is engaged with the upper main surface of the anode electrode plate 4 and positioned (FIG. 1). The shape and the number of the locking portions 18b are not limited to those shown in FIG. 3, and for example, as shown in FIG. 4, a plurality of substantially trapezoidal locking portions 1 are provided.
It may be configured by 8b. In addition, the tubular insulating member 18
May be made of mica or a polyimide molded body.

Further, by inserting the anode electrode plate 4 into the tubular insulating member 18, as shown in FIG. 2, the side surface portion 18c of the tubular insulating member 18 and the outer peripheral portion 2 of the semiconductor substrate 2 are provided.
A space SP surrounded by c and the notch 4a of the anode electrode plate 4 is defined, and the space SP is filled with silicon rubber 20. Therefore, the semiconductor substrate 2 is not only adhered to the anode electrode plate 4 by the silicon rubber 20, but also to the cylindrical insulating member 18. Moreover,
A slight gap 22 is formed between the anode electrode plate 4 and the cylindrical insulating member 18, and the silicone rubber 2 is also provided in the gap 22.
The anode electrode plate 4 and the tubular insulating member 18 are bonded to each other. As a result, the semiconductor substrate 2 is protected by the silicone rubber 20 on the front and back surfaces of the end side portion and the outer peripheral portion, and is fixed to the anode electrode plate 4 with sufficient adhesive strength. Although silicon rubber is used as the insulating adhesive member here, a varnish-based material may be used instead.

As shown in FIG. 1, the convex portion 8b of the external anode electrode 8 is inserted into the through hole 18a of the tubular insulating member 18 and is in contact with the upper main surface of the anode electrode plate 4.

On the other hand, the cathode electrode plate 6 is provided with a through hole 30 in the center thereof, and correspondingly, the external cathode electrode 10 is also provided with a recess 32 having the same sectional shape as the through hole 30, The gate electrode support 34 is slidably fitted in the fitting hole formed by the recess 32 and the through hole 30.

One end of a conductive wire 38 is connected to the internal gate electrode 36, and the other end of the conductive wire 38 penetrates through the head of the gate electrode support 34 and further through the casing 28. 40 through the casing 28
, And the external gate electrode 42 is welded at its end.

The gate electrode support 34 is formed of an insulating member, and a spring 44 is brought into contact with the lower end of the support 34 to urge it upward. As a result, the internal gate electrode 36 is firmly pressed against and electrically connected to the gate metallization layer 14.

Further, the gate electrode support 34 has the through hole 3 of the cathode electrode plate 6 having the same cross section as described above.
0 and the recess 32 of the external cathode electrode 10, the gate electrode support 34 is inserted into the insertion hole.
In other words, it functions as a pile, and the cathode electrode plate 6 is positioned so as not to be displaced from the predetermined position of the external cathode electrode 10.

In the external anode electrode 8 and the external cathode electrode 10, metal ring-shaped flanges 24 and 26 are fixed to the outer circumferences of the bases 8a and 10a, respectively, and these flanges 24 and 26 are opened in the casing 28. The ends are fixed by brazing.

Next, the procedure for assembling the semiconductor device shown in FIG. 1 will be described with reference to the assembly and disassembly of FIG.

(1) First, the casing 28 in which the insulating tube 40 is horizontally penetrated and fixed at a predetermined position of the cylindrical portion is prepared.

(2) A ring-shaped flange 2 around the circumference
The external cathode electrode 10 to which 6 is fixed is placed so that the convex portion 10b thereof faces upward, and the spring 44 is inserted into the concave portion 32 formed in the center.

(3) The casing 28 is attached to the insulating tube 4
0 is a groove 10 formed on the upper surface of the external cathode electrode 10.
It is placed on the flange 26 so that it comes to the position of c.

(4) The gate electrode support 34 having the internal gate electrode 36 attached to its head is fitted into the through hole 30 of the external cathode electrode 10. At this time, the conducting wire 38 connected to the internal gate electrode 36 is passed through the insulating tube 40.

The internal gate electrode 36 has a hole 34 axially penetrating the gate electrode support 34 as shown in FIG.
It is attached by inserting the other end of the conducting wire 38, one of which is connected to the internal gate electrode 36, into a and pulling it out from the notch 34b formed in the lower portion of the gate electrode support 34.

(5) The cathode electrode plate 6 is placed on the external cathode electrode 10 so that the head portion of the gate electrode support 34 is inserted into the through hole 30 in the center thereof.

(6) Next, the semiconductor substrate 2 fixed to the anode electrode plate 4 and the tubular insulating member 18 is inserted into the casing 28 with the cathode metallization layer 16 facing down, and the cathode electrode plate 6 is formed. Place it on the upper surface of. As described above, the semiconductor substrate 2 is fixed to the anode electrode plate 4 in advance. The fixing method will be described with reference to FIGS. 6 to 9.

First, as shown in FIG. 6, the tubular insulating member 1
8 so that the locking portion 18b is located below,
Place it in place. Then, the anode electrode plate 4 is fitted into the tubular insulating member 18 so that the cutout portion 4a faces upward.

Next, the semiconductor substrate 2 is placed on the anode electrode plate 4 so that the anode metallized layer 12 contacts the anode electrode plate 4 (FIG. 7). As a result, the space portion SP is defined by the side surface portion 18c of the tubular insulating member 18, the semiconductor substrate 2, and the cutout portion 4a of the anode electrode plate 4.

Then, a weight 50 for preventing displacement is placed on the semiconductor substrate 2 (FIG. 8). After that, the silicon rubber 20 is filled in the space SP, and the silicon rubber 2 is heated at a predetermined temperature for a certain time while the weight 28 is placed on the silicon rubber 2
Solidify 0 (FIG. 9).

As described above, in this embodiment, the cylindrical insulating member 18, the semiconductor substrate 2, and the anode electrode plate 4 form the space SP, and the space SP is filled with the silicone rubber 20. Therefore, silicone rubber 20
It is possible to prevent excess silicone rubber from leaking out during application. Therefore, it is not necessary to remove excess silicon rubber after the silicone rubber 20 is solidified. Further, it is not necessary to use a jig for molding the silicone rubber 20. As a result, it is possible to prevent the breakdown voltage of the semiconductor device from becoming unstable due to the contamination of the silicon rubber 20, and it is possible to improve the reliability of the semiconductor device.

Further, the manufacturing process can be simplified because the work of removing the silicone rubber is unnecessary.

Moreover, the insulator existing between the anode metallized layer 12 and the cathode metallized layer 16 is the silicon rubber 20 and the side surface portion 18c of the tubular insulating member 18,
Anode metallized layer 12 and cathode metallized layer 16
The creepage distance between and becomes longer, and the breakdown voltage of the semiconductor device can be increased.

Further, since the silicon rubber 20 is used as the insulating adhesive member and has a certain elasticity even when solidified, it is also excellent as a protective material for the end portion of the semiconductor substrate 2. The same effect can be obtained when a varnish material is used instead of the silicone rubber 20.

(7) Next, returning to the description of the method for assembling the semiconductor device. The convex portion 8b of the external anode electrode 8 is inserted into the casing 28 from above the anode electrode plate 4, and the flange 24 is aligned with the upper end portion of the casing 28.

(8) The flange 26 of the external cathode electrode 10 and the flange 24 of the external anode electrode 8 are fixed to the end surface of the casing 28 by brazing.

(9) Finally, the external gate electrode 42 is
It is fixed by welding to the end of the conductive wire 38 which is passed through the insulating tube 40 and exposed to the outside.

In this way, the semiconductor device of FIG. 1 is assembled.

<Modification> In the above embodiment, the locking portion 18b is provided at one end of the tubular insulating member 18,
This is not an essential configuration requirement of this embodiment,
For example, as shown in FIG. 11, a cylindrical insulating member 18 having no locking portion 18b may be used. However, in this case, one end of the side surface portion 18c of the tubular insulating member 18 needs to be configured to engage with the cutout portion 4a of the anode electrode plate 4. That is, the space SP may be formed in cooperation with the semiconductor substrate 2 and the anode electrode plate 4 in a state where the tubular insulating member 18 is engaged with the anode electrode plate 4 (FIG. 11).

When the tubular insulating member 18 of FIG. 11 is used, it is necessary to fix the semiconductor substrate 2 to the anode electrode plate 4 and the tubular insulating member 18 by a procedure different from the above. Therefore, the procedure will be described with reference to FIGS. 12 to 15.

First, as shown in FIG. 12, the anode electrode plate 4 is predetermined so that the notch 4a finished so that it can be engaged with one end of the side surface 18c of the tubular insulating member 18 is located above. Place in position. Then, one end of the side surface portion 18c of the tubular insulating member 18 is engaged with the cutout portion 4a, and the tubular insulating member 18 is positioned and placed on the anode electrode plate 4. The tubular insulating member 18 and the anode electrode plate 4 are bonded to each other by a silicone rubber 20 described later,
At this point, it is desirable to bond the anode electrode plate 4 and the tubular insulating member 18 in advance by using an appropriate adhesive.

Then, in the same manner as described above, the semiconductor substrate 2
To fix. That is, the semiconductor substrate 2 is placed on the anode electrode plate 4 so that the anode metallized layer 12 contacts the anode electrode plate 4 (FIG. 13). Following that,
A weight 50 for preventing displacement is placed on the semiconductor substrate 2 (FIG. 14), and in that state, the silicon rubber 20 is attached to the side surface portion 18c of the cylindrical insulating member 18, the semiconductor substrate 2, and the anode electrode plate. Space portion SP defined by the notch portion 4a of 4
Then, the silicone rubber 20 is solidified by performing a predetermined heat treatment (FIG. 15).

Further, the width of the cutout portion 4a of the anode electrode plate 4 is set to be substantially the same as the thickness of the side surface portion 18c of the tubular insulating member 18, so that the tubular insulating member 18 serves as the anode electrode plate 4 as shown in FIG. Alternatively, the upper end portion and the side surface portion 18c may be brought into contact with each other at two positions. In this case, the joint strength becomes larger than that in the joined state of FIG.

Further, as shown in FIG. 16, the outer diameter of the anode electrode plate 4 and the inner diameter of the tubular insulating member 18 are substantially matched so that the outer diameter portion of the anode electrode plate 4 is the inner circumference of the tubular insulating member 18. You may make it join by a surface.

Further, as shown in FIG. 17, the silicon rubber 20 extends not only to the tubular insulating member 18, the anode electrode plate 4 and the semiconductor substrate 2, but also to the cathode electrode 6.
The silicon rubber 20 may be filled in the space SP. In this case, the semiconductor substrate 2 is processed by a procedure different from the above.
Need to be fixed to the anode electrode plate 4, the cathode electrode plate 6 and the tubular insulating member 18. Therefore, the procedure will be described with reference to FIGS. 19 to 21.

First, the tubular insulating member 18 is attached to the engaging portion 1 thereof.
8b is placed at a predetermined position so that it is located below. Then, the anode electrode plate 4 is fitted into the tubular insulating member 18 so that the cutout portion 4a faces upward. Further, the semiconductor substrate 2 is placed on the anode electrode plate 4 so that the anode metallized layer 12 is in contact with the anode electrode plate 4, and then the cathode electrode plate 6 is placed on the cathode metallized layer 16 (FIG. 19). . As a result, the side surface portion 18c of the tubular insulating member 18, the semiconductor substrate 2, and the anode electrode plate 4 are formed.
And the cathode electrode plate 6 define the space portion SP.

Then, in the same manner as described above, the semiconductor substrate 2
To fix. That is, the weight 50 for preventing the positional displacement is placed on the semiconductor substrate 2 (FIG. 20), and in that state,
After filling the space SP with the silicone rubber 20, a predetermined heat treatment is performed to solidify the silicone rubber 20 (FIG. 21).

Further, the side surface portion 18c of the tubular insulating member 18
The other end may be located above the horizontal level (the one-dot chain line in FIG. 22) of the lower main surface 2b of the semiconductor substrate 2.

By the way, in the fixing method as described above, there is a possibility that the filling silicon rubber 20 permeates into the gap between the anode metallization layer 12 and the anode electrode plate 4 due to the capillary phenomenon and solidifies there. In this case, the electrical connection between the anode metallization layer 12 and the anode electrode plate 4 may be poor, and when the permeated silicone rubber 20 forms a thick film, a hollow portion is formed inside. When formed and pressure is applied from the outside of the external anode electrode 8 and the external cathode electrode 10, the central portion of the semiconductor substrate 2 may be bent and may be damaged in the worst case.

Therefore, as shown in FIG. 23, if a closed loop-shaped (ring-shaped) groove 52 is provided in the contact region R on the lower main surface of the anode electrode plate 4 that contacts the anode metallization layer 12, such a situation occurs. Is eliminated.

That is, even if the silicone rubber 20 permeates into the gap between the semiconductor substrate 2 and the anode electrode plate 4, the groove 5
Permeation is blocked at the portion 2 and does not permeate further inside, and the above-mentioned problem is solved.

The number of the ring-shaped grooves 52 is not limited to two as shown in FIG. 23, but there is a case where the penetration of the silicone rubber 20 cannot be completely prevented by only one, and the number is too large. However, since the electrical contact area with the anode metallized layer 12 is reduced, about two layers are desirable. Further, the cross-sectional shape of the groove 52 is not limited to the triangular shape as shown in the figure, but may be modified as necessary.

Further, the semiconductor substrate 2 is connected to the anode electrode plate 4
When it is mounted on and fixed to the semiconductor substrate, air may remain in the gap between the semiconductor substrate 2 and the anode electrode plate 4, or gas may be generated inside due to heating for solidification of the silicon rubber 20. In such a case, the electrical connection between the semiconductor substrate 2 and the anode electrode plate 4 will be poor, so as shown in FIG. 24, the air vent hole 54 penetrating the anode electrode plate 4 and communicating with the space SP, and the anode electrode. You may make it form the similar air vent hole 58 provided in the center part of the board 4.

B. Second Embodiment FIG. 25 is a vertical sectional view showing a second embodiment of the semiconductor device according to the present invention. The major difference between the second embodiment and the first embodiment is that the tubular insulating member 18 is engaged with the cathode electrode plate 6. That is, in the second embodiment,
The cathode electrode plate 6 is finished so that its diameter is larger than that of the semiconductor substrate 2, and a ring-shaped cutout portion concentric with the outer periphery is formed on the upper main surface thereof. The space SP is defined by the tubular insulating member 18, the cathode electrode plate 6, and the semiconductor substrate 2 with the cathode electrode plate 6 fitted in the tubular insulating member 18.
Silicon rubber 20 is filled in the space SP.
The other basic structure is the same as that of the first embodiment.

As described above, according to the second embodiment, the semiconductor substrate 2 is bonded to the cathode electrode plate 6 and the tubular insulating member 18 by the silicon rubber 20, so that the semiconductor substrate 2 is fixed with sufficient bonding strength. be able to. Further, since the space SP is filled with the silicon rubber 20, the same effect as that of the first embodiment, that is, (1) the reliability of the semiconductor device can be improved, and (2) the manufacturing process is simplified. (3) The effect that the breakdown voltage of the semiconductor device can be increased is obtained.

C. Third Embodiment FIG. 26 is a vertical sectional view showing a third embodiment of the semiconductor device according to the present invention. The major difference of this embodiment from the first embodiment is that a mesa type thyristor is formed in the semiconductor substrate 2 in the first embodiment, whereas a planar type thyristor is formed in the third embodiment. The other basic configurations are the same.

FIG. 27 is a partially enlarged view of the semiconductor substrate 2. In this planar type thyristor, a part of the P emitter layer PE and the N base layer NB is exposed on the lower main surface of the semiconductor substrate 2 and the P surface is exposed on the exposed surface of the N base layer NB.
The structure is almost the same as that of the mesa type thyristor except that the layer P is formed. Further, a SiO2 layer 64 is provided on the outer peripheral portion of the lower main surface of the semiconductor substrate 2, a field plate 66 for relaxing an electric field is further provided on the SiO2 layer 64, and a P layer is formed through an opening of the SiO2 layer 64. It is electrically connected to P. Like this PN
In the planar type thyristor in which the junction is exposed on the main surface (lower main surface), the space between the layers exposed on the main surface can be relatively wide. Therefore, in the mesa type, the side surface protection effect of the silicon rubber 20 is important, whereas in the planar type, the adhesive function is more important.

In the third embodiment, the diameter of the semiconductor substrate 2 is made substantially equal to the inner diameter of the tubular insulating member 18, but the anode electrode plate 4 and the tubular insulating member 18 are taken into consideration in consideration of the above-mentioned adhesive action. Gaps 60 and 62 of about 0.1 to 0.2 mm are formed between the semiconductor substrate 2 and the side surface portion 18c of the cylindrical insulating member 1. And the space S
The silicon rubber 20 is filled in P and the gaps 60 and 62, and the same effect as that of the above-described embodiment is obtained. Note that FIG.
As shown in, when the field plate 66 for relaxing the electric field is provided on the outer peripheral portion of the semiconductor substrate 2, not only is the space SP filled with the silicon rubber 20,
It is preferable to protect the outer peripheral portion with silicone rubber 20.

D. Fourth Embodiment In the third embodiment, one main surface of the semiconductor substrate 2 (see FIG. 27) is used.
Although the description has been given of the case of the planar type thyristor in which the PN junction is exposed on the lower main surface of the PN junction, the present invention has PN junctions on both main surfaces.
It can also be applied to the type in which the junction is exposed, for example, the planar type thyristor shown in FIG.

In the figure, n ⁺ regions are formed on both main surface sides of the outer peripheral end of the semiconductor substrate 2 and are electrically connected to the field limit ring 68.

[0080]

As described above, according to the present invention, the space between the cylindrical insulating member, the second electrode plate and the semiconductor substrate is formed by connecting the cylindrical insulating member with the second electrode. Since the space is formed and the space is filled with the insulating adhesive member, the semiconductor substrate is fixed not only to the second electrode plate but also to the cylindrical insulating member, and the adhesive strength of the semiconductor substrate is improved. be able to. Further, by engaging the tubular insulating member with the second electrode, a predetermined space is defined and the filling range of the insulating adhesive member is limited, so that the excess insulating adhesive member flows out. Since there is no need for removing the insulating adhesive member, the insulating adhesive member can be prevented from being contaminated, and a highly reliable semiconductor device can be obtained.

[Brief description of drawings]

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

FIG. 2 is a partially enlarged view of the semiconductor device of FIG.

FIG. 3 is a perspective view showing an example of a tubular insulating member.

FIG. 4 is a perspective view showing another example of a tubular insulating member.

5 is an exploded view of the semiconductor device of FIG.

FIG. 6 is a diagram showing a procedure for fixing a semiconductor substrate to an anode electrode plate.

FIG. 7 is a diagram showing a procedure for fixing a semiconductor substrate to an anode electrode plate.

FIG. 8 is a diagram showing a procedure for fixing the semiconductor substrate to the anode electrode plate.

FIG. 9 is a diagram showing a procedure for fixing the semiconductor substrate to the anode electrode plate.

FIG. 10 is a diagram showing a procedure for attaching an internal gate electrode to a gate electrode support.

FIG. 11 is a partial enlarged view showing a first modification of the semiconductor device according to the present invention.

FIG. 12 is a diagram showing a procedure for fixing the semiconductor substrate to the anode electrode plate in the first modified example.

FIG. 13 is a diagram showing a procedure for fixing the semiconductor substrate to the anode electrode plate in the first modification.

FIG. 14 is a diagram showing a procedure for fixing the semiconductor substrate to the anode electrode plate in the first modified example.

FIG. 15 is a diagram showing a procedure for fixing the semiconductor substrate to the anode electrode plate in the first modified example.

FIG. 16 is a partial enlarged view showing a second modification of the semiconductor device according to the present invention.

FIG. 17 is a partial enlarged view showing a third modification of the semiconductor device according to the present invention.

FIG. 18 is a partial enlarged view showing a fourth modification of the semiconductor device according to the present invention.

FIG. 19 is a diagram showing a procedure of fixing the semiconductor substrate to the anode electrode plate and the cathode electrode plate in the fourth modified example.

FIG. 20 is a diagram showing a procedure for fixing the semiconductor substrate to the anode electrode plate and the cathode electrode plate in the fourth modified example.

FIG. 21 is a diagram showing a procedure of fixing the semiconductor substrate to the anode electrode plate and the cathode electrode plate in the fourth modified example.

FIG. 22 is a partial enlarged view showing a fifth modification of the semiconductor device according to the present invention.

FIG. 23 is a view showing an anode electrode plate provided with an auxiliary groove.

FIG. 24 is a view showing an anode electrode plate provided with an air vent hole.

FIG. 25 is a vertical sectional view showing a second embodiment of the semiconductor device according to the present invention.

FIG. 26 is a vertical sectional view showing a third embodiment of the semiconductor device according to the present invention.

27 is a partially enlarged view of the semiconductor device of FIG.

FIG. 28 is a partial enlarged view showing a fourth embodiment of the semiconductor device according to the present invention.

FIG. 29 is a partially enlarged view showing a conventional semiconductor device.

FIG. 30 is a partially enlarged view showing a conventional semiconductor device.

[Explanation of symbols]

 2 Semiconductor Substrate 4 Anode Electrode Plate 4a Notch 6 Cathode Electrode Plate 8 External Anode Electrode 10 External Cathode Electrode 12 Anode Metallization Layer 14 Gate Metallization Layer 16 Cathode Metallization Layer 16 18 Cylindrical Insulation Member 20 Silicon Rubber 28 Casing 52 Grooves 54, 56 , 58 Air vent hole

Claims (16)

[Claims] 1. A semiconductor substrate, a first metallized layer provided on one main surface of the semiconductor substrate, a second metallized layer provided on the other main surface of the semiconductor substrate, and one surface thereof. A first metallization layer in contact with the first metallization layer
Electrode plate having a larger outer dimension than the first electrode plate, and one main surface of the second electrode plate being in contact with the second metallization layer.
Of the electrode plate, and a substantially cylindrical insulating member that fits the outer peripheral portion of the second electrode, wherein the cylindrical insulating member is coupled to the second electrode, A space is formed by the second electrode plate and the semiconductor substrate, and the space is filled with an insulating adhesive member, so that the outer peripheral end of the semiconductor substrate is protected by the insulating adhesive member. The semiconductor device is fixed to at least the second electrode plate and the tubular insulating member in a state. 2. The semiconductor device according to claim 1, wherein a cutout portion is provided in an outer peripheral portion of the second electrode plate on the one main surface side. 3. The one end of the cylindrical insulating member is the second end.
The semiconductor device according to claim 2, wherein the semiconductor device is engaged with the notch of the electrode plate. 4. A locking portion is provided so as to project inward from an inner peripheral surface on one end side of the tubular insulating member, and the tubular insulating member is coupled to the second electrode, The semiconductor device according to claim 1, wherein the engaging portion is engaged with the other main surface of the second electrode plate. 5. The semiconductor according to claim 1, wherein a through hole is provided in an outer peripheral portion of the second electrode plate, and the space portion communicates with the other main surface side of the second electrode plate by the through hole. apparatus. 6. The semiconductor device according to claim 1, wherein a closed loop groove is provided in a contact region of one main surface of the second electrode plate which is in contact with the second metallization layer. 7. The semiconductor device according to claim 6, wherein at least one or more closed loop grooves are further provided in the contact region. 8. A through hole is provided in the second electrode plate corresponding to the groove, and the groove forms the second hole by the through hole.
8. The semiconductor device according to claim 6, which is communicated with the other main surface side of the electrode plate. 9. The outer dimensions of a second contact region of the one main surface of the second electrode plate, which is in contact with the second metallization layer, are the first main surface of the one main surface of the first electrode plate. Is larger than the contacting first contact area of the metallization layer, and when the first contact area is projected onto one main surface of the second electrode plate, the projected area is within the second contact area. The semiconductor device according to claim 1, which is located. 10. The outer dimension of the semiconductor substrate is the second dimension.
Is smaller than the outer dimensions of the electrode plate and the inner dimension of the cylindrical insulating member, and a PN junction is provided on the semiconductor substrate, and a part of the PN junction is exposed at the outer peripheral end of the semiconductor substrate. Item 1. The semiconductor device according to item 1. 11. The semiconductor substrate is provided with a PN junction so as to be exposed on the one main surface of the semiconductor substrate, and the external dimensions of the semiconductor substrate are substantially the same as the external dimensions of the second electrode plate. The semiconductor device according to claim 1, wherein 12. A PN junction is provided on the semiconductor substrate so as to be exposed on both main surfaces of the semiconductor substrate, and
The semiconductor device according to claim 3, wherein an exposed region on the other main surface side of the semiconductor substrate faces the cutout portion of the second electrode plate. 13. An exposed region is formed by providing a PN junction on the semiconductor substrate so as to be exposed on at least one main surface of the semiconductor substrate, and a ring-shaped electric field relaxation region is formed on an outer peripheral portion of the exposed region. The semiconductor device according to claim 1, wherein a metal film connected to a part of the electric field relaxation region is formed, and the insulating adhesive member covers the metal film. 14. A method of assembling a semiconductor device in which a semiconductor substrate having electrode layers formed on both main surfaces is sandwiched between first and second electrode plates, the method comprising: (a) forming two opposing openings. A step of preparing a casing having: (b) a step of fixing the semiconductor substrate to the second electrode plate and a substantially tubular insulating member, wherein the tubular insulating member has an inner end on one side thereof. A locking member is provided so as to project inward from the peripheral surface, and the second member is provided on the tubular insulating member.
And (b-1) placing the second insulating plate so that the other end side of the tubular insulating member faces upward, and fitting the second electrode plate into the tubular insulating member. b-2) placing the semiconductor substrate at a predetermined position on the upper surface of the second electrode plate in a state of being fitted into the tubular insulating member, and (b-3) inside the tubular insulating member. Filling the space formed by the peripheral surface, the upper surface of the second electrode plate and the outer peripheral end of the semiconductor substrate with an insulating adhesive member, and (b-4) solidifying the insulating adhesive member. The semiconductor substrate is formed by the cylindrical insulating member and the second insulating member.
A step of obtaining a combined body fixed to the electrode plate of, and (c) a step of fixing the semiconductor substrate, and (c) the combined body, the first electrode plate, and the first and second external electrodes, One electrode plate is in contact with the main surface of the semiconductor substrate opposite to the second electrode plate, and the first and second external electrodes are the ones of the first electrode plate and the second electrode plate. A step of accommodating each of the outer main surfaces in the casing so that the main surfaces are in contact with each other and parallel to the opening of the casing; and (d) the first external electrode and the second external electrode. Fixing the electrodes to the respective ends of the openings of the casing, and a method of assembling a semiconductor device. 15. A method of assembling a semiconductor device in which a semiconductor substrate having electrode layers formed on both main surfaces is sandwiched between first and second electrode plates, comprising: (a) forming two opposing openings. A step of preparing a casing having: (b) a step of fixing the semiconductor substrate to the second electrode plate and a substantially tubular insulating member, wherein one end of the tubular insulating member is the first No. 2 has a shape adapted to the outer peripheral portion of the electrode plate, and (b-1) an opening on the one end side of the tubular insulating member in a state where the other end side of the tubular insulating member faces up. With the second electrode plate, (b-2) placing the semiconductor substrate at a predetermined position on the upper surface of the second electrode plate, and (b-3) of the tubular insulating member. The space formed by the inner peripheral surface, the upper surface of the second electrode plate, and the outer peripheral edge of the semiconductor substrate. A step of filling an insulating adhesive member in part, (b-4) wherein by solidifying the insulating bonding member, wherein the semiconductor body said tubular insulating member and the second
A step of obtaining a combined body fixed to the electrode plate of, and (c) a step of fixing the semiconductor substrate, and (c) the combined body, the first electrode plate, and the first and second external electrodes, One electrode plate is in contact with the main surface of the semiconductor substrate opposite to the second electrode plate, and the first and second external electrodes are the ones of the first electrode plate and the second electrode plate. Housing the casing in such a manner that it is in contact with the respective outer major surfaces and that the major surfaces are parallel to the openings of the casing; and (d) the first external electrode and the second outer electrode. Fixing an external electrode to each opening end of the casing, and a method of assembling a semiconductor device. 16. A method of assembling a semiconductor device in which a semiconductor substrate having electrode layers formed on both main surfaces is sandwiched between first and second electrode plates, comprising: (a) forming two opposing openings. And (b) fixing the semiconductor substrate to the first and second electrode plates and the substantially tubular insulating member, wherein the tubular insulating member has one end portion thereof. Has a shape adapted to the outer peripheral portion of the second electrode plate, and (b-1) one end portion of the tubular insulating member in a state in which the other end side of the tubular insulating member faces up. Closing the side opening with the second electrode plate, (b-2) placing the semiconductor substrate at a predetermined position on the upper surface of the second electrode plate, (b-3) the semiconductor substrate Placing the second electrode plate on the upper surface of the tubular insulating member; Filling a space formed by an inner peripheral surface, an upper surface of the second electrode plate, an outer peripheral end of the semiconductor substrate, and a side surface of the first electrode plate with an insulating adhesive member; (b-5) ) By solidifying the insulative adhesive member, the semiconductor base is made to have the tubular insulating member and the first insulating member.
And a step of obtaining a combined body fixed to the second electrode plate, and a step of fixing the semiconductor substrate including: (c) the combined body and the first and second external electrodes,
The first and second external electrodes are in contact with the outer main surfaces of the first electrode plate and the second electrode plate, respectively, and their main surfaces are parallel to the opening of the casing. And a step of: (d) fixing the first external electrode and the second external electrode to respective end portions of the opening of the casing. How to assemble the device.