DE102009061178B3 - Power semiconductor device - Google Patents

Abstract

A power semiconductor device comprising: a substrate (21) having a circuit pattern (20) on an upper surface thereof; a semiconductor element (22, 24) fixed to the circuit pattern (20); a cylindrical electrode (12) having a first end and a second end having an open end at the second end, the cylindrical electrode (12) being mounted upright on the substrate (21) such that its first end abuts the circuit pattern (20 ) is attached; and a resin package (10) covering said substrate (21), said semiconductor element (22, 24) and said cylindrical electrode (12) such that a back surface of said substrate (21) and said second end of said cylindrical electrode (12) in air, the cylindrical electrode (70) including a double structure in which an inner wall portion (74) and an outer wall portion (76), both formed by pressing, are spaced from each other by a predetermined distance, the second end the cylindrical electrode (70) is a turned portion (75) formed into a curved shape by the pressing action, and the first end of the cylindrical electrode (70) is a part of the outer wall portion (76) located on the opposite side of the cylindrical wall turned portion (75) is arranged so that at the first end of the outer wall portion (76) is attached to the circuit pattern (20) and the inner wall portion (74) is not in contact with the circuit pattern (20).

Description

The present invention relates to a power semiconductor device in which a part of a cylindrical electrode is exposed from the resin.

DE 10 2008 008 141 A1 describes a semiconductor module for mounting to a cooling element. In particular, the semiconductor module has a module housing, whose one side faces the cooling element and whose other side has a plurality of openings. Each of the openings has a boundary sealed by an internal contact electrically connected to a component of the semiconductor module.

A power semiconductor device has a structure in which semiconductor elements such as a power MOSFET or an IGBT (Insulated Gate Bipolar Transistor) and a diode with a resin are sealed so as to be encapsulated and protected.

The resin encapsulation is carried out by using a transfer molding process. That is, injection of molding resin into a cavity formed of metal die casting molds is carried out after a semiconductor device array is inserted into the cavity. It should be noted that the semiconductor device device to be sealed with the resin has a structure in which semiconductor elements and cylindrical electrodes are connected on a circuit pattern provided on a metal base substrate.

The cylindrical electrode is a part connected to the aforementioned semiconductor element in the resin so that the semiconductor element is connected to an external circuit.

Therefore, transfer molding is performed in such a manner that the cylindrical electrode is attached upright to the metal base substrate so that one end of the cylindrical electrode having an open end is exposed from the resin.

In the transfer molding process, since clamping of the dies for enclosing the semiconductor device assembly is performed between an upper die and a lower die, injection of the casting resin into the cavity formed by the metal dies is carried out under the condition that the one end of the cylindrical die Electrode is in contact with the inner wall of the upper die.

From the viewpoint of ensuring the reliability of the power semiconductor device, it is desirable that the thickness of the semiconductor device array agrees with the height of the cavity formed by the molds to avoid excessive pressure being applied to the semiconductor device array when the molds are clamped become.

Techniques for increasing the reliability of the power semiconductor device are disclosed in, for example, U.S.P. JP 2007-184315 A and the JP H10-116 962 A disclosed.

It is common for the thickness of the semiconductor device device to have a certain amount of variation depending on the thickness variations of the metal base substrate, the height variations of the cylindrical electrode and the thickness variations of the solder connecting the cylindrical electrode to the metal base substrate. That is, if the thickness of the semiconductor device array is thicker than the height of the cavity formed by the molds, a problem occurs in which the cylindrical electrode and the metal base substrate may be damaged because the cylindrical electrode is pressed very hard on the semiconductor device array becomes.

Further, the inner diameter of a part of the cylindrical electrode to be exposed from the resin package is forced to decrease due to the strong pressure from the upper mold. As a result, there arises a problem that a pin electrode can not easily slide in the cylindrical electrode.

Further, there is a problem that the molding resin can flow into the inside of the cylindrical electrode when the electrode is obliquely provided with respect to the base substrate, or when the thickness of the semiconductor device array is thinner than the height of the cavity formed in the molds ,

In order that the thickness of the semiconductor device array agrees with the height of the cavity formed in the molds, each part of the semiconductor device array should be formed with high accuracy, and the semiconductor device array should be composed with high accuracy. This results in high manufacturing costs and a complicated process.

In view of the above-described problems, an object of the present invention is to provide a power semiconductor device in which problems due to transfer molding are solved and reliability is improved.

This object is achieved by a power semiconductor device according to claim 1.

Other and further objects, features and advantages of the present invention will become apparent from the following description with reference to the drawings. From the figures show:

1 an external perspective view of a power semiconductor device according to a first embodiment;

2 a cross-sectional view of in 1 shown power semiconductor device, as seen in the direction of the arrows I;

3 a flowchart showing a manufacturing method for the power semiconductor device;

4 a semiconductor device device according to the first embodiment;

5 a cavity formed between an upper die and a lower die;

6 an external perspective view of the power semiconductor device, are inserted into the pin electrodes;

7 a cylindrical electrode having one end bent almost at right angles;

8th a cylindrical electrode having a part whose inner diameter is larger than that of another part thereof;

9 a power semiconductor device having a cylindrical electrode whose one end is formed in a thin shape;

10 a cross-sectional view of a power semiconductor device according to a second embodiment;

11 a cross-sectional view of a power semiconductor device according to a third embodiment;

12 a cross-sectional view of a power semiconductor device according to a fourth embodiment; and

13 an enlarged view of an in 12 shown part in which a pin electrode is added.

First embodiment

A first embodiment, with reference to 1 to 9 is not claimed. The same materials and elements are denoted by the same reference numerals and need not be redundantly described. This also applies to the other embodiments.

1 FIG. 16 is an external perspective view of a power semiconductor device according to the first embodiment. FIG. 2 is a cross-sectional view of the in 1 shown power semiconductor device, as seen in the direction of the arrows I.

In the power semiconductor device according to the embodiment, as shown in FIG 1 is shown a part of a cylindrical electrode 12 on the surface of a resin 10 open. Next are mounting holes 14 on the surface of the resin 10 formed for attaching a radiator such as a heat sink. In this embodiment, the length, width and thickness of the resin 10 assumed to be 76 mm, 45 mm and 8 mm, respectively. The size of the resin 10 however, it is not limited to this.

As in 2 is shown is a heat sink 16 in the resin 10 arranged. The heat sink 16 is made of a metal whose main material is copper. The rear surface of the heat sink 16 lies on the resin 10 open. A circuit pattern 20 of 0.3 mm thickness made of metal whose main material is copper is on the upper surface of the heat sink 16 via a thermally conductive electrically insulating connection layer 18 arranged.

The size of a metal base substrate 21 is about 40 mm in length and 45 mm in width. The heat sink 16 , the thermally conductive insulating compound layer 18 and the circuit pattern 20 will be here together the metal base substrate 21 called.

The back surface of an IGBT 22 and the back surface of an FWDi (freewheeling diode) are connected to the circuit pattern 20 of the metal base substrate 21 through a solder 26 soldered.

Here, a gate electrode and an emitter electrode are on the upper surface of the IGBT 22 educated. Further, a collector electrode is on the back surface of the IGBT 22 educated. Further, an anode electrode is on the upper surface of the FWDi 24 educated. In addition, a cathode electrode is on the back surface of the FWDi 24 educated.

The IGBT and the FWDi 24 are through the circuit pattern 22 and aluminum wires 28 connected so that they form a desired circuit. The IGBT 22 and the FWDi 24 are collectively called a semiconductor element in the following.

Further, the power semiconductor device includes a cylindrical electrode 12 , The cylindrical electrode 12 is shown for connecting the semiconductor element to an external circuit.

Basically, the cylindrical electrode 12 a cylindrical shape whose inner diameter and outer diameter are 0.85 mm and 2.85 mm, respectively. One end of the cylindrical electrode 12 has a larger inner diameter than that of the section described above and is an open end.

Specifically, the inner diameter of the cylindrical electrode 12 becomes larger the closer one gets to the edge thereof, so that the inner diameter and the outer diameter at the edge thereof become 1.5 mm and 3.5 mm, respectively. In other words, the end of the cylindrical electrode 12 has a trumpet-like shape. Such an end of the cylindrical electrode 12 is to the outside of the resin 10 openly lying. On the other hand, the other end of the cylindrical electrode 12 on the circuit pattern 20 soldered.

The power semiconductor device according to the present embodiment has the above-described construction. Hereinafter, a manufacturing method of the power semiconductor device of the present embodiment will be described with reference to FIG 3 shown flowchart described. First, a in 3 shown step 100 described.

In step 100 For example, a semiconductor device device is manufactured. As used herein, the term "semiconductor device array" refers to a structural element that is to be sealed with resin by a transfer molding process.

The semiconductor device device of the present embodiment is shown in FIG 4 shown. As in 4 is shown is the cylindrical electrode 12 upright on the circuit pattern 20 mounted so that the above-mentioned one end of the cylindrical electrode 12 points upward, while at the other end of the cylindrical electrode 12 with the circuit pattern 20 is soldered.

Then, the semiconductor element becomes the circuit pattern 20 soldered, and wire bonding using an aluminum wire 28 is executed so that the production of the semiconductor device array is completed. When the semiconductor element array is manufactured, the processing goes to step 102 ,

In step 102 For example, the semiconductor device arrangement is provided between metal die casting molds. In step 104 that's the step 102 follows, the dies are clamped together. steps 102 and 104 are now referring to 5 described.

In this embodiment, the metal molds for forming the resin package include an upper mold 32 and a lower mold 30 , The semiconductor device array becomes in a cavity 34 provided inside the metal molds so that a back surface of the metal base substrate 21 in contact with an inner wall of the lower mold 30 is brought, and the one end of the cylindrical electrode 12 becomes in contact with an inner wall of the upper mold 32 brought.

When the metal molds are clamped under such a condition, the one end becomes the cylindrical electrode 12 as a result of the downward pressure from the upper mold 32 bent. Then the cylindrical electrode adheres 12 at the upper mold 32 because of this bend. Then the processing goes to step 106 ,

In step 106 Casting resin is injected into the cavity formed in the die casting molds. The molding resin of the present embodiment may be made of, for example, epoxy resin, but is not limited thereto. In this step, as in the case of the prior art, the molten casting resin is pressurized so as to be injected into the cavity of the die casting molds. After injecting the molten casting resin into the cavity formed in the dies, the processing goes to step 108 ,

In step 108 For example, a power semiconductor device sealed with resin is taken out of the metal molds. Thereafter, a pin electrode 40 , which is made of brass, but not limited to, with a size of 0.64 mm square in an open end of the cylindrical electrode 12 introduced (step 110 ).

Here, a conductive adhesive mainly made of epoxy resin can be used to reinforce the attachment between the pin electrode 40 and the cylindrical electrode 12 to be used. An external perspective view of the power semiconductor device after inserting the pin electrode 40 is in 6 shown.

After the step 110 is, as necessary, a heat treatment at a temperature of about 180 ° C for solidifying the resin 10 and the conductive adhesive for finishing a power semiconductor device.

Generally, it is preferable that the thickness of the semiconductor device device is the same like the height of the inside of the metal molds (the height of the inside of the metal molds denotes a height of the cavity defined by the double-sided arrow in FIG 5 is designated).

However, it is common for the thickness of the semiconductor device array to have a certain amount of variation depending on the thickness variations of the metal base substrate 21 of the height variations of the cylindrical electrode, the thickness variations of the solder connecting the cylindrical electrode to the metal base substrate, and inclination of the cylindrical electrode.

Therefore, when the thickness of the semiconductor device array is thicker than the height of the cavity formed in the die casting molds, a problem occurs in which the cylindrical electrode and the metal base substrate can be damaged because the cylindrical electrode is pressed very hard on the semiconductor device array ,

Further, if the inner diameter of the part of the cylindrical electrode exposed from the resin package is reduced due to the disturbance of the cylindrical electrode caused by the strong pressure from the upper die, there is a problem that the pin electrode is no longer easy to insert the cylindrical electrode can slide.

Further, a problem arises that cast resin may enter the inside of the cylindrical electrode when the cylindrical electrode is provided obliquely with respect to the base substrate or when the thickness of the semiconductor device array is made thinner than the height of the cavity formed by the die casting molds becomes.

For manufacturing the thickness of the semiconductor device array in accordance with the height of the cavity formed by the die casting molds, each part of the semiconductor device array should be formed with high accuracy, and the semiconductor device array should be manufactured with high accuracy. As a result, there arises a problem that the manufacturing cost becomes high and the manufacturing process becomes complicated.

The manufacturing method of the power semiconductor device according to the present embodiment can solve the above problems. In this embodiment, when the dies are clamped, the one end of the cylindrical electrode becomes 12 by the downward pressure from the upper mold 32 bent.

Therefore, the downward pressure of the upper die can 32 by the bending of the cylindrical electrode 12 be relieved, instead of the pressure directly on the connecting portion between the cylindrical electrode 12 and the metal base substrate 21 is exercised. Thus, the problem with respect to the damage exerted on the cylindrical electrode and the metal base substrate can be solved.

A resin plate having reinforcing properties / stretch properties may be adhered to the inner surface of the upper die. Even in such a case, equivalent advantages or effects as in the present embodiment can be obtained as long as the downward pressure is applied from the upper die to the cylindrical electrode via the resin plate.

Further, the degree of adhesion between the cylindrical electrode 12 and the upper die 32 due to the bending of the one end of the cylindrical electrode during the clamping operation can be improved. Therefore, the problem of entering the casting resin into the inside of the cylindrical electrode 12 can be solved even if the thickness of the semiconductor device array shows variability or when the cylindrical electrode is provided obliquely with respect to the base substrate.

The present embodiment also contributes to the improvement of productivity. Further, the semiconductor device arrangement can conversely be installed in the cavity formed in the dies, as compared with the case of the above construction. In this case, the inner wall of the lower die is in contact with the one end of the cylindrical electrode, and the inner wall of the die is in contact with the back surface of the metal base substrate. This brings about the same advantages as that of the present embodiment. More specifically, the advantages of the present embodiment can be achieved when the metal molds are clamped to enclose the back surface of the metal base substrate and the one end of the cylindrical electrode.

As the inner diameter of the cylindrical electrode 12 gradually larger toward the edge of the one end of the cylindrical electrode 12 becomes, the filling pressure, which is provided by injecting the casting resin into the metal molds, on the cylindrical electrode 12 such that the cylindrical electrode 12 is pressed against the inner wall of the upper die. Therefore, the degree of adhesion between the cylindrical electrode 12 and the upper die 32 be improved.

Further, the inner diameter of the cylindrical electrode 12 gradually larger toward the edge of the one end of the cylindrical electrode 12 becomes, the inner diameter of the cylindrical electrode by the pressure from the upper die 32 widened, and thereby the problem that the pin electrode can no longer slide in the cylindrical electrode due to the reduced inner diameter of the cylindrical electrode is solved.

According to the power semiconductor device of the present embodiment, the part of the cylindrical electrode in which the inner diameter of the cylindrical electrode serves 12 bigger than the other section is and from the resin 12 is free, as a guide for the insertion of the pin electrode. This makes it easy to insert the pin electrode.

Further, according to the above construction, the conductive adhesive applied to the cylindrical electrode for increasing the adhesion between the pin electrode 40 and the cylindrical electrode 12 is positioned within the cylindrical electrode, even if the mounting position of the conductive adhesive has some disadvantages.

Although the inner diameter of the cylindrical electrode 12 gradually larger toward the edge of the one end of the cylindrical electrode 12 In the present embodiment, the present embodiment is not limited thereto.

The cylindrical electrode of the present embodiment is characterized in that it is bent when the dies are clamped, thereby preventing the open end of the cylindrical electrode from becoming narrow and preventing excessive pressure from being applied to the connecting portion between the cylindrical and the cylindrical electrodes Electrode and the metal base substrate to be exercised.

It is understood that the cylindrical electrode 50 can achieve the same advantages achieved by the present embodiment, if it has an end portion, as in 7 is shown, which is bent substantially rectangular so that it has an enlarged inner diameter which is larger than that of the other portion. In this case, the bent portion of the cylindrical electrode 50 absorb the pressure directed down from the upper die by bending it.

For example, the same advantages of the present embodiment can be achieved when the portion of the cylindrical electrode 52 is provided with the maximum inner diameter in the one end portion, but not at the outermost edge thereof, as in 8th is shown.

For example, the advantages of this embodiment can be increased when the plate thickness of the one end of the cylindrical electrode 54 with the larger inner diameter than that of the other section is thinner than that of the other section, as in 9 is shown.

More precisely, one end of the cylindrical electrode 54 may be shaped such that the difference between the outer diameter and the inner diameter is smaller than that of the other portion. If such a cylindrical electrode 54 can be used, the flexibility of the cylindrical electrode 54 be enlarged. Thereby, the above advantages can be increased.

Here, a cylindrical electrode used for a main electrode for achieving high current operation has an enlarged size. Further, such a cylindrical electrode has a large difference between the outer diameter and the inner diameter. Thus, the above structure is particularly effective for such a cylindrical electrode.

This structure is also effective when the cylindrical electrode is slightly inclined with respect to the metal base substrate because the cylindrical electrode is long in a longitudinal direction.

When a power semiconductor device is used under high temperature conditions or when a power semiconductor device is large, thermal deformation of the power semiconductor device becomes serious.

In such a thermal deformation, there is a fear that the resin peels off and ruptures, resulting from the portion where the cylindrical electrode is exposed from the resin. However, according to the above structure, there is no danger of peeling or cracking of the resin. Namely, when one end of the cylindrical electrode is thinner than the other portion as mentioned above, it becomes easy for the one end of the cylindrical electrode to follow the thermal deformation of the resin.

Now, the high-temperature strength of a power semiconductor device can be increased when the semiconductor element is made of a SiC substrate.

Then, the high-temperature strength is improved, and the peeling or cracking of the resin can be prevented from occurring when the semiconductor element is made of a SiC substrate is while the structure described above is used.

Further, the semiconductor element made of a SiC substrate is useful for improving electrical strength and enabling high current operation.

For example, a part corresponding to the "part of the cylindrical electrode where the inner diameter is larger than that of the other portion" may be attached to a cylindrical electrode having a uniform inner diameter. Namely, the cylindrical electrode may be composed of a plurality of parts instead of a single part.

In this case, the cylindrical electrode having a uniform inner diameter may be made of a good heat conductive material such as aluminum or copper. On the other hand, the part corresponding to the "part of the cylindrical electrode where the inner diameter is larger than that of the other portion" may be made of a material having a spring property such as phosphor bronze or a flexible material such as aluminum or solder.

The electrode of the present embodiment is not limited to the cylindrical electrode. The cylindrical electrode can also be connected to the external circuit using a screw instead of using the pin electrode.

Further, the pin electrode can be fixed to the cylindrical electrode by press fitting. Of course, the sizes of the cylindrical electrode, the structures of the metal base substrate, and the types of the semiconductor element are not limited to those in the embodiment described above.

Second embodiment

A second embodiment, with reference to 10 is not claimed. 10 FIG. 10 is a cross-sectional view of a power semiconductor device. FIG. In this embodiment, the shape of a cylindrical electrode is different from that in the first embodiment.

In the present embodiment, the inner diameter of the cylindrical electrode becomes 60 gradually larger toward the edge of a first end to be connected to a circuit pattern. The first end of the cylindrical electrode 60 gets to the circuit pattern 20 soldered. A second end of the cylindrical electrode 60 that of the resin 10 is open, has a larger inner diameter than that of the other portion, as in the first embodiment.

The power semiconductor device according to the present embodiment can be manufactured by the same processes as in FIG 3 is shown. The above-mentioned cylindrical electrode 60 gets to the circuit pattern 20 soldered in a process of manufacturing the semiconductor device array.

Here, the inner diameter of the first end of the cylindrical electrode 60 gradually larger toward the edge of the first end of the cylindrical electrode 60 can, the cylindrical electrode 60 slightly upright on the circuit pattern 20 be attached.

More specifically, when the cylindrical electrode is long in the longitudinal direction, there arises a problem that the cylindrical electrode is inclined with respect to the metal base substrate due to the variation in the amount of solder that is supplied and the variation in the size of the soldering tool. According to the present embodiment, the above-mentioned problem can be solved.

When the area of contact between the first end of the cylindrical electrode and the circuit pattern is reduced, a sufficient amount of solder can not be supplied between the first end of the cylindrical electrode and the circuit pattern. Thus, a space can be formed between the first end of the cylindrical electrode and the circuit pattern. In this case, there arises a problem that the productivity is reduced due to the entrance of cast resin into the inside of the cylindrical electrode.

Increasing the amount of solder to solve the above problem may result in another problem in which the cylindrical electrode is forced to tilt on the circuit pattern. In the present embodiment, however, the problems can be solved because the contact area between the cylindrical electrode 60 and the circuit pattern 20 is great

In this embodiment, since the contact surface between the cylindrical electrode 60 and the circuit pattern 20 is large, a fraction of the connecting portion between the cylindrical electrode 60 and the circuit pattern 20 hardly caused by stress of thermal deformation due to the temperature cycle. Therefore, the reliability of the power semiconductor device can be increased.

The connecting portion between the cylindrical electrode 60 and the circuit pattern 20 can be damaged by vibration or static charge caused by an external electrode such as a pin electrode connected to the cylindrical electrode 20 connected is.

However, according to the present embodiment, the contact surface is between the first end of the cylindrical electrode 60 and the circuit pattern 20 big, and the cylindrical electrode 60 will be against the circuit pattern 20 pressed. Such a construction prevents the joint portion from being damaged, and hence the reliability can be improved.

Third embodiment

A third embodiment, with reference to 11 is not claimed. 11 FIG. 10 is a cross-sectional view of a power semiconductor device. FIG. In this embodiment, the shape of the cylindrical electrode differs from that in the first embodiment.

In the present embodiment, one end of the cylindrical electrode 62 that of the resin 10 is free, curved. A turned or turned portion is formed at the one end of the cylindrical electrode, and the turned portion lies from the surface of the resin 10 free. An edge of the turned portion is in the resin 10 buried. Next is the other end of the cylindrical electrode 62 also provided with a turned section.

Generally, when an edge of one end of a cylindrical electrode is exposed from a surface of a molding resin, there is a fear that peeling or cracking of the resin resulting from the edge occurs due to the thermal deformation caused by the temperature cycle.

It is also feared that peeling or cracking of resin resulting from the edge occurs due to vibration or static charge resulting from an external electrode such as a pin electrode. However, according to this embodiment, the edge of the turned portion is in the resin 10 buried and is not open on the surface of the resin. Therefore, the above concerns can be solved, and a high-reliability power semiconductor device can be manufactured.

The power semiconductor device according to the present embodiment can be replaced by the same processes as in FIG 3 shown produced. Through the processes can, as the turned section, on the one end of the cylindrical electrode 62 is formed, is bent during the clamping of the die-casting molds, the advantages are achieved equivalent to those obtained in the first embodiment.

In addition, the transfer printing of the material of the cylindrical electrode 62 to the upper die, because the edge of the turned portion of the cylindrical electrode does not contact the upper die, instead a middle portion of the turned portion is in contact with the upper die. Therefore, the cleaning frequency of the upper die can be suppressed.

In this embodiment, the turned portions of the one end and the other end of the cylindrical electrode 62 For example, be made by compression molding.

According to the press molding, it is easy to provide the turned portion with the curvature, as in FIG 11 is shown.

Also, the elastic force of the turned portion can be increased by springback generated during the formation. Therefore, the above advantages can be enhanced.

Fourth embodiment

A fourth embodiment according to the present invention will now be described with reference to FIG 12 and 13 described. 12 FIG. 10 is a cross-sectional view of the power semiconductor device. FIG. 13 is an enlarged top view of a part of 12 and shows a state in which a pin electrode in the in 12 shown construction is pressed.

In this embodiment, the shape of a cylindrical electrode is different from that in the first embodiment. In particular, the present embodiment provides a structure suitable for a power semiconductor device in which a pin electrode is pressed into a cylindrical electrode.

The line semiconductor device according to this embodiment includes a cylindrical electrode 70 with a double structure. Like in 13 is shown contains the cylindrical electrode 70 an inner wall section 74 and an outer wall portion 76 ,

The inner wall section 74 and the outer wall portion 76 are separated from each other by a certain distance while they are on a connecting part are connected. The connecting part is open on the resin.

The cylindrical electrode 70 The present embodiment is manufactured by press work or the like. Since the above-mentioned connecting part is made by refolding the cylindrical electrode, the connecting part will be referred to as a turned or turned or bent portion hereinafter. The turned section 75 is indicated by a dashed line in 13 designated.

The rotated section 75 the cylindrical electrode 70 lies on the surface of the resin 10 open. On the other hand, a part of the outer wall portion 76 the cylindrical electrode facing the turned section 75 is arranged to the circuit pattern 20 soldered.

Here is the inner wall section 74 neither with the circuit pattern 20 soldered still in contact with the circuit pattern 20 , The inner wall section 74 however, it extends parallel to the outer wall portion 76 while keeping a regular distance.

The power semiconductor device according to the present embodiment can be manufactured by the same processes as described in FIG 3 are shown.

As mentioned above, the outer wall becomes 76 the cylindrical electrode 70 to the circuit pattern 20 soldered to complete the fabrication of the semiconductor device array. Then, the semiconductor device array is set in the cavity formed in the die-casting, so that the back surface of the metal base substrate 21 is in contact with the inner wall of the lower die and the turned portion 75 is in contact with the inner wall of the upper die.

Next, the dies are clamped so that the rotated portion 75 is bent. The subsequent processes are the same as those in the first embodiment.

There is a power semiconductor device in which a pin electrode is pressed into a cylindrical electrode fixed in a resin package. With respect to this type of device, there arises a problem that the cylindrical electrode can not exert a strong repulsive force on the pin electrode during the pressing for insertion because the cylindrical electrode is fixed in the resin.

The above-mentioned repulsive force can be obtained when the cylindrical electrode is made of elastic material or the pin electrode is made of elastic material. In this case, however, the cylindrical electrode or the pin electrode must be manufactured and provided with a high degree of accuracy, so that the manufacturing cost increases.

More specifically, a power semiconductor device for handling a high current such as 100 A is manufactured to have many electrodes. For such a device, there arises a problem that the manufacturing process becomes complicated because it becomes necessary to connect many pin electrodes.

The pin electrode may be bonded to the cylindrical electrode on the cylindrical electrode with a conductive resin or solder instead of being pressed into the cylindrical electrode. In this case, the cylindrical electrode should be mounted upright on the base substrate before sticking.

However, since it is difficult for the cylindrical electrode to stand upright due to the small repulsive force, it is necessary to use a tool for holding the cylindrical electrode in the upright position.

In contrast, according to the present embodiment, the cylindrical electrode 70 with the double structure covering the inner wall section 74 and the outer wall portion 76 contains, solve the above problems.

That is, when the pin electrode 72 into the cylindrical electrode 70 is pressed, the inner wall section 74 to the outer wall portion 76 moves because the inner wall section 74 not with the resin 10 is covered and parallel to the outer wall section 76 emotional. As a result, the pin electrode becomes 72 a sufficient repulsive force from the inner wall 74 given.

Therefore, it is possible to manufacture a high-reliability power semiconductor device in which a pin electrode is securely fixed by press-fitting without increasing the manufacturing cost thereof.

Even if the pin electrode is attached to the cylindrical electrode with conductive adhesive or solder instead of press-fitting, the pin electrode can be mounted upright on the metal base substrate even before the conductive adhesive or the solder is attached because of the sufficient restoring force from the inner wall 74 ,

Consequently, it is not necessary to use any tool for holding the pin electrode / cylindrical electrode in the upright position before attaching the conductive adhesive or the solder. Further advantages by bending the turned section 75 are achieved when the dies are clamped together, are the same as those described in the first embodiment.

It is preferable that the cylindrical electrode 70 this embodiment is made of a material having a good spring property such as phosphor bronze or brass. However, the present invention is not limited thereto.

Next is the cylindrical electrode 70 preferably cylindrical for providing the cylindrical electrode 70 on the upper surface of the metal base substrate 21 while automatic equipment is used in the manufacturing process of a semiconductor device array. However, the present invention is not limited thereto.

In the present embodiment, the cylindrical electrode becomes 70 by pressing or the like to form the rotated portion 75 educated. However, the present invention is not limited thereto as long as the same shape can be achieved.

In the same manner, the metal base substrate described above is exemplified, but it should not be construed as limiting.

Namely, the substrate is not limited to the upper structure as long as it is made possible for the semiconductor element and the cylindrical electrode to be fixed on its surface. For example, the advantages of the present invention are not lost even if a substrate having a ceramic substrate whose surface is provided with a metal foil such as a Cu foil or an Al foil and a radiation plate overlaps on the back surface of the ceramic substrate a metal foil or solder is attached.

Claims (1)

Power semiconductor device comprising: a substrate ( 21 ), which is a circuit pattern ( 20 ) on an upper surface thereof; a semiconductor element ( 22 . 24 ) connected to the circuit pattern ( 20 ) is attached; a cylindrical electrode ( 12 ) having a first end and a second end having an open end at the second end, the cylindrical electrode ( 12 ) upright on the substrate ( 21 ) is mounted such that its first end on the circuit pattern ( 20 ) is attached; and a resin package ( 10 ), which is the substrate ( 21 ), the semiconductor element ( 22 . 24 ) and the cylindrical electrode ( 12 ) such that a rear surface of the substrate ( 21 ) and the second end of the cylindrical electrode ( 12 ) are exposed to air, the cylindrical electrode ( 70 ) contains a double structure in which an inner wall section ( 74 ) and an outer wall section ( 76 ), both of which are formed by pressing, are spaced from each other by a predetermined distance, the second end of the cylindrical electrode (FIG. 70 ) a turned section ( 75 ), which is formed by the pressing operation in a curve shape, and the first end of the cylindrical electrode ( 70 ) a part of the outer wall portion ( 76 ), which is on the opposite side of the turned section ( 75 ) is arranged so that at the first end of the outer wall portion ( 76 ) on the circuit pattern ( 20 ) and the inner wall section ( 74 ) not in contact with the circuit pattern ( 20 ).

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