JP2014072385A - Semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor device which can reduce effective inductance.SOLUTION: A semiconductor device comprises: a first IGBT element 10a having a first emitter electrode 11a and a first collector electrode 12a on the same plane; and a second IGBT element 10b having a second emitter electrode 11b and a second collector electrode 12b on the same plane. The first collector electrode 12a and the second emitter electrode 11b are arranged to face each other. The semiconductor device further comprises a P bus bar 33 and an N bus bar 36 which are arranged between the first collector electrode 12a and the second emitter electrode 11b and overlap each other when viewed from a lamination direction.

Description

  The present invention relates to a semiconductor device.

  2. Description of the Related Art Conventionally, a semiconductor device in which an IGBT (Insulated Gate Bipolar Transistor) element that is a switching element and a diode element that is a rectifying element are stacked and connected is known (see, for example, Patent Document 1). In the semiconductor device described in Patent Document 1, the collector electrode of the IGBT element is mounted on the heat dissipation plate, the inter-element connection conductor is joined to the emitter electrode by a conductive resin, and the anode electrode of the diode element is further conducted thereon. The IGBT element and the diode element are stacked and connected in the vertical direction by bonding with a conductive resin.

JP 2000-164800 A

  Here, in a semiconductor device, for example, it is important to reduce the effective inductance in order to reduce a surge voltage that is a voltage in a direction that hinders a steady current. In order to reduce the effective inductance, a bus bar (hereinafter referred to as P bus bar) for connecting the positive electrode of the power source and the element, and a bus bar (hereinafter referred to as N bus bar) for connecting the negative electrode of the power source and the element, It is important to increase the negative mutual inductance by arranging them close to each other. However, in the conventional semiconductor device described above, the effective inductance may be increased depending on the arrangement of the P bus bar and the N bus bar.

  This invention is made | formed in view of the said situation, and makes it a subject to provide the semiconductor device which can reduce an effective inductance.

  In order to solve the above-described problem, a semiconductor device according to the present invention is arranged to be stacked on a first switching element having a first emitter electrode and a first collector electrode on the same plane, and stacked on the first switching element. A second switching element having two emitter electrodes and a second collector electrode on the same plane; a P bus bar connected to the first collector electrode of the first switching element; and a second emitter electrode of the second switching element. An N bus bar, wherein the first switching element and the second switching element are arranged so that the first collector electrode and the second emitter electrode face each other, and the P bus bar and the N bus bar are the first collector electrode And the second emitter electrode and overlap each other when viewed from the stacking direction.

  In this semiconductor device, a switching element (so-called lateral switching element) having an emitter electrode and a collector electrode on the same plane is used as the first and second switching elements. The first and second switching elements are arranged so that the first collector electrode and the second emitter electrode face each other, and the P bus bar and the N bus bar are formed between the first collector electrode and the second emitter electrode. They are arranged in between and overlap each other when viewed from the stacking direction. As a result, the P bus bar and the N bus bar run side by side from directly above the element in a state of being close to each other. Therefore, the mutual inductance can be increased and the effective inductance can be reduced.

  The first rectifier element having the first anode electrode and the first cathode electrode on the same plane, and the first rectifier element are disposed so as to be stacked on the first rectifier element, and the second anode electrode and the second cathode electrode are disposed on the same plane. And a second rectifying element, the first rectifying element and the second rectifying element are arranged so that the first cathode electrode and the second anode electrode face each other, and the P bus bar is the first cathode electrode Preferably, the N bus bar is connected to the second anode electrode, and the P bus bar and the N bus bar are disposed between the first cathode electrode and the second anode electrode. Thereby, the P bus bar and the N bus bar can also be run parallel to the rectifying element in a state where they are close to each other, and the mutual inductance can be increased and the effective inductance can be reduced.

  Moreover, it is preferable that the 1st switching element and the 2nd switching element are connected to the heat sink, and the heat sink is connected to the cooler via the lubricant. Thus, by providing the heat sink and the cooler without using an insulating member, the heat dissipation of the semiconductor device can be improved.

  The first switching element and the second switching element are disposed so that the first emitter electrode and the second collector electrode face each other, and the first emitter electrode and the second collector electrode are linearly connected to each other. It is preferable that Thereby, the current path between the first emitter electrode and the second collector electrode can be made the shortest, and the effective inductance can be reduced also in this respect.

  Moreover, it is preferable that both the first emitter electrode and the second collector electrode are connected to the same output bus bar via a conductor block. Thereby, for example, the connection by the conductor is not required between the first switching element and the second switching element, and it is possible to reduce the electrical resistance and the processing cost.

  According to the present invention, it is possible to provide a semiconductor device capable of reducing effective inductance.

1 is a schematic plan view showing a semiconductor device according to an embodiment of the present invention. (A) is sectional drawing along the II (a) -II (a) line of FIG. 1, (b) is sectional drawing along the II (b) -II (b) line of FIG. (A) is sectional drawing which shows the lateral IGBT element of the semiconductor device of FIG. 1, (b) is sectional drawing which shows the lateral diode element of the semiconductor device of FIG. FIG. 7 is a schematic plan view showing a semiconductor device according to a modification of the semiconductor device of FIG. 1.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description, the same or equivalent elements will be denoted by the same reference numerals, and redundant description will be omitted.

  First, a semiconductor device according to an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a schematic plan view showing a semiconductor device according to an embodiment of the present invention. 2A is a cross-sectional view taken along line II (a) -II (a) in FIG. 1, and FIG. 2B is a cross-sectional view taken along line II (b) -II (b) in FIG. . 3A is a sectional view showing a lateral IGBT element of the semiconductor device of FIG. 1, and FIG. 3B is a sectional view showing a lateral diode element of the semiconductor device of FIG.

  As shown in FIG. 1, the semiconductor device 1 of this embodiment has a stacked structure of an upper phase module 2 and a lower phase module 3. As shown in FIGS. 1 and 2, the upper phase module 2 includes a first IGBT element 10 a that is a switching element, a first diode element 20 a that is a rectifying element, a heat sink 31, a cooler 32, and a P bus bar 33. And an output bus bar 35.

  The lower phase module 3 includes a second IGBT element 10b that is a switching element, a second diode element 20b that is a rectifying element, a heat sink 31, a cooler 32, an N bus bar 36, and an output bus bar 35. Yes. The upper phase module 2 and the lower phase module 3 are electrically connected to each other through a conductor 37.

  As shown in FIG. 3A, the first IGBT element 10a is a so-called lateral IGBT element having an electrode surface on which the first emitter electrode 11a and the first collector electrode 12a are provided on the same surface. In the first IGBT element 10 a, the surface opposite to the electrode surface is an insulating surface, and the insulating surface is connected to the heat sink 31 with solder 38.

  As shown in FIG. 3B, the first diode element 20a is a so-called lateral diode element having electrode surfaces on which the first anode electrode 21a and the first cathode electrode 22a are provided on the same surface. When viewed from the direction orthogonal to the stacking direction, the first diode elements 20a are juxtaposed so that the electrode surfaces thereof are located on the same plane as the electrode surfaces of the first IGBT elements 10a. In the first diode element 20a, the surface opposite to the electrode surface is an insulating surface, and the insulating surface is connected to the heat sink 31 with solder 38.

  As shown in FIG. 3A, the second IGBT element 10b is a so-called lateral IGBT element having an electrode surface on which the second emitter electrode 11b and the second collector electrode 12b are provided on the same surface. The second IGBT element 10b is disposed so as to be stacked on the first IGBT element 10a. In the second IGBT element 10 b, the surface opposite to the electrode surface is an insulating surface, and the insulating surface is connected to the heat radiating plate 31 with solder 38.

  As shown in FIG. 3B, the second diode element 20b is a so-called lateral diode element having an electrode surface on which the second anode electrode 21b and the second cathode electrode 22b are provided on the same surface. The second diode element 20b is disposed so as to be stacked on the first diode element 20a. When viewed from the direction orthogonal to the stacking direction, the second diode elements 20b are juxtaposed so that the electrode surfaces thereof are located on the same plane as the electrode surfaces of the second IGBT elements 10b. In the second diode element 20b, the surface opposite to the electrode surface is an insulating surface, and the insulating surface is connected to the heat radiating plate 31 with solder 38.

  As shown in FIG. 1, the first IGBT element 10a and the second IGBT element 10b have a first collector electrode 12a and a second emitter electrode 11b facing each other, and a first emitter electrode 11a and a second collector electrode 12b. Are arranged so as to face each other. Further, in the first diode element 20a and the second diode element 20b, the first cathode electrode 22a and the second anode electrode 21b face each other, and the first anode electrode 21a and the second cathode electrode 22b face each other. So as to face each other.

  The heat radiating plate 31 is made of a material that can easily control the thermal conductivity and the coefficient of thermal expansion. For example, the heat radiating plate 31 is made of aluminum carbon silicon (AlSiC), copper molybdenum (Cu—Mo), or the like. One surface of the heat dissipation plate 31 is connected to the first IGBT element 10a, the second IGBT element 10b, the first diode element 20a, and the second diode element 20b. Further, the other surface of the heat radiating plate 31 is (thermally) connected to the cooler 32 via grease 39.

  The cooler 32 has, for example, a flow path through which a cooling medium flows, and includes an IGBT element (first IGBT element 10a and second IGBT element 10b) and a diode element (first diode element 20a and second diode element 20b). It is a device for absorbing and cooling the amount of heat released through the heat radiating plate 31. The cooler 32 is connected to the heat sink 31 via a lubricant such as grease 39.

  As shown in FIG. 2A, one end side of the P bus bar 33 is divided into two. One of the two parts is connected to the first collector electrode 12a of the first IGBT element 10a, and the other is connected to the first cathode electrode 22a of the first diode element 20a. The P bus bar 33 extends in one direction from directly above the electrodes 12a and 22a, and the other end is connected to the positive electrode of the power source (not shown).

  Further, as shown in FIG. 2B, the N bus bar 36 is divided into two ends at one end side. One of the two parts is connected to the second emitter electrode 11b of the second IGBT element 10b, and the other is connected to the second anode electrode 21b of the second diode element 20a. The N bus bar 36 extends in one direction (the same direction as the direction in which the P bus bar 33 extends) from directly above the electrodes 11b and 21b, and the other end is connected to the negative electrode of the power source (not shown). .

  As shown in FIGS. 1 and 2, both the P bus bar 33 and the N bus bar 36 are disposed between the first IGBT element 10a and the first diode element 20a, and the second IGBT element 10b and the second diode element 20b. ing. Further, the P bus bar 33 and the N bus bar 36 are arranged so as to overlap each other (co-run) as viewed from the stacking direction.

  The output bus bar 35 includes an output bus bar 35x included in the upper phase module 2 and an output bus bar 35y included in the lower phase module 3. The output bus bar 35x and the output bus bar 35y are connected to each other by a conductor 37. ing. The output bus bar 35x is connected via the conductor block 34 to the first emitter electrode 11a of the first IGBT element 10a and the first anode electrode 21a of the first diode element 20a. The output bus bar 35y is connected via the conductor block 34 to the second collector electrode 12b of the second IGBT element 10b and the second cathode electrode 22b of the second diode element 20b.

  Such an output bus bar 35 linearly conducts the first emitter electrode 11a and the second collector electrode 12b that are arranged to face each other. In addition, the output bus bar 35 linearly conducts the first anode electrode 21a and the second cathode electrode 22b that are arranged to face each other. The P bus bar 33, the N bus bar 36, and the output bus bar 35 are formed of a wiring material used for supplying power to a semiconductor element such as an IGBT, and a conductor such as copper or aluminum is used, for example.

  Next, a modification of the semiconductor device shown in FIG. 1 will be described with reference to FIG. FIG. 4 is a schematic plan view showing a semiconductor device according to a modification of the semiconductor device of FIG.

  As shown in FIG. 4, in the semiconductor device 1a, unlike the semiconductor device 1 shown in FIG. 1, the conductor 37 that connects the upper phase module 2 and the lower phase module 3 is not a constituent element. The output bus bar 35 has the same configuration (structure integrally molded) in the upper phase module 2 and the lower phase module 3. The other configuration of the semiconductor device 1a is the same as that of the semiconductor device 1 shown in FIG.

  As described above, in the present embodiment, the first IGBT element 10a (second IGBT element 10b) having the first emitter electrode 11a (second emitter electrode 11b) and the first collector electrode 12a (second collector electrode 12b) on the same plane is used. It has been. The first IGBT element 10a and the second IGBT element 10b are arranged so that the first collector electrode 12a and the second emitter electrode 11b face each other, and the P bus bar 33 and the N bus bar 36 are formed by the first collector electrode 12a. And the second emitter electrode 11b, and overlap each other when viewed from the stacking direction. As a result, the P bus bar 33 and the N bus bar 36 run side by side from directly above the element while being close to each other.

Here, the effective inductance L _OP (H) when a pair of conductors are provided in parallel with each other and run side by side is obtained by the following equation (1).
L _OP = L _S1 + L _S2 -2M (1)
Where L _S1 is the self-inductance (H) of one conductor, L _S2 is the self-inductance (H) of the other conductor, and M is the mutual inductance (H) between the pair of conductors. From the above equation (1), in order to reduce the effective inductance L _OP it is possible to reduce the self-inductance of each conductor, and it is important to increase the mutual inductance between the conductors.

The self-inductance L _S (H) of the conductor is obtained by the following equation (2)
L _S = μ ₀ × N ² × 1 × S (2)
Where μ ₀ is the magnetic permeability (H / m), N is the number of turns, l is the length of the conductor (m), and S is the cross-sectional area (m ² ) of the conductor.

Further, the mutual inductance M (H) between the conductors is obtained by the following equation (3).
M = μ ₀ × 1 × (In (2l / d) −1) / 2π (3)
Where d is the distance between the conductors.

  From the above formula (3), in the pair of conductors that are provided in parallel and run side by side, the mutual inductance increases as the distance of the parallel runs increases and the distance between the conductors decreases. From the above equation (1), the effective inductance decreases as the mutual inductance increases.

  Therefore, according to the present embodiment, as described above, the P bus bar 33 and the N bus bar 36 run side by side from directly above the element while being close to each other. Can be lengthened. Thus, the mutual inductance between the P bus bar 33 and the N bus bar 36 is increased, and the effective inductance can be reduced.

  Further, in the present embodiment, as described above, the first diode element 20a having the first anode electrode 21a and the first cathode electrode 22a on the same surface, and the first diode element 20a are disposed so as to be stacked. A second diode element 20b having two anode electrodes 21b and a second cathode electrode 22b on the same plane, and the first diode element 20a and the second diode element 20b include the first cathode electrode 22a and the second anode electrode. 21b is disposed to face each other, the P bus bar 33 is connected to the first cathode electrode 22a, the N bus bar 36 is connected to the second anode electrode 21b, and the P bus bar 33 and the N bus bar 36 are The diode element 20a, which is disposed between the cathode electrode 22a and the second anode electrode 21b, Also for 0b, the P bus bar 33 and N bus bar 36, it is possible to travel together from immediately above the element in a state of being close to each other, it is possible to reduce the inductance by increasing the mutual inductance.

  Here, in the conventional semiconductor device, when an IGBT element having an electrode surface on both surfaces facing each other (so-called vertical IGBT element) is used, there is a concern that current may flow through the heat sink to which the IGBT element is connected. It had been. Therefore, it is necessary to insulate between the heat sink and the cooler, and an insulating member such as a ceramic substrate is provided between the heat sink and the cooler. In this respect, since the so-called lateral IGBT element is used in the semiconductor devices 1 and 1a of the present embodiment as described above, it is possible to prevent current from flowing through the heat sink 31. Therefore, it is not necessary to provide an insulating member between the heat radiating plate 31 and the cooler 32, and the heat radiating plate 31 is directly connected to the cooler 32 via a lubricant (for example, grease). Thus, the heat radiating plate 31 can be directly cooled by the cooler 32, and the heat radiating characteristics can be improved due to a decrease in thermal resistance. That is, the present embodiment enables both reduction of item inductance and improvement of heat dissipation performance.

  Note that both the upper-phase module 2 and the lower-phase module 3 improve the heat dissipation characteristics by the heat radiation under the element. Further, since the insulating member becomes unnecessary, the number of articles and the processing cost can be reduced.

  In the present embodiment, as described above, the first IGBT element 10a and the second IGBT element 10b are arranged so that the first emitter electrode 11a and the second collector electrode 12b face each other, and the first emitter electrode 11a The second collector electrode 12b is linearly connected to each other. Here, from the above equation (2), the self-inductance of the conductor becomes smaller as the length of the conductor becomes shorter. By shortening the current path between the first emitter electrode 11a and the second collector electrode 12b, The self-inductance can be reduced and the effective inductance can be reduced.

  In the semiconductor device 1 a shown in FIG. 4, the first emitter electrode 11 a and the second collector electrode 12 b are both connected to the same output bus bar 35 through the conductor block 34. Thereby, for example, the connection by the conductor between the 1st IGBT element 10a and the 2nd IGBT element 10b becomes unnecessary, and it can aim at the fall of electrical resistance and the reduction of processing cost.

  As described above, the semiconductor device 1 according to the present embodiment can achieve both reduction in effective inductance and improvement in heat dissipation performance.

  The preferred embodiments of the present invention have been described above. However, the semiconductor device according to the present invention is not limited to the semiconductor devices 1 and 1a according to the embodiments, and the gist described in each claim is not changed. It may be modified by or applied to others.

  For example, in FIG. 1, the P bus bar 33 and the N bus bar 36 running side by side extend in a direction intersecting the stacking direction, but the direction in which the P bus bar and the N bus bar extend is not limited to this. Alternatively, the P bus bar and the N bus bar may be extended in other directions as long as the P bus bar and the N bus bar can be run side by side.

  In the above embodiment, the IGBT elements 10a and 10b are exemplified as the switching elements and the diode elements 20a and 20b are exemplified as the rectifier elements. However, the present invention is not limited to this, and various switching elements and rectifiers are used. An element can be used.

DESCRIPTION OF SYMBOLS 1,1a ... Semiconductor device, 2 ... Upper phase module, 3 ... Lower phase module, 10a ... 1st IGBT element, 10b ... 2nd IGBT element, 11a ... 1st emitter electrode, 11b ... 2nd emitter electrode, 12a ... 1st collector Electrode, 12b ... second collector electrode, 20a ... first diode element, 20b ... second diode element, 21a ... first anode electrode, 21b ... second anode electrode, 22a ... first cathode electrode, 22b ... second cathode electrode , 31 ... radiator plate, 32 ... cooler, 33 ... P bus bar, 34 ... conductor block, 35, 35x, 35y ... output bus bar, 36 ... N bus bar, 37 ... conductor, 38 ... solder, 39 ... grease.

Claims (5)

A first switching element having a first emitter electrode and a first collector electrode on the same plane;
A second switching element disposed to be stacked on the first switching element and having a second emitter electrode and a second collector electrode on the same plane;
A P bus bar connected to the first collector electrode of the first switching element;
An N bus bar connected to the second emitter electrode of the second switching element,
The first switching element and the second switching element are arranged to face each other such that the first collector electrode and the second emitter electrode face each other,
The P bus bar and the N bus bar are disposed between the first collector electrode and the second emitter electrode, and overlap each other when viewed from the stacking direction. A first rectifying element having a first anode electrode and a first cathode electrode on the same plane;
A second rectifier element disposed on the first rectifier element and having a second anode electrode and a second cathode electrode on the same plane;
The first rectifying element and the second rectifying element are arranged to face each other so that the first cathode electrode and the second anode electrode face each other.
The P bus bar is connected to the first cathode electrode;
The N bus bar is connected to the second anode electrode;
The semiconductor device according to claim 1, wherein the P bus bar and the N bus bar are disposed between the first cathode electrode and the second anode electrode. The first switching element and the second switching element are connected to a heat sink,
The semiconductor device according to claim 1, wherein the heat radiating plate is connected to a cooler via a lubricant. The first switching element and the second switching element are disposed to face each other such that the first emitter electrode and the second collector electrode face each other,
The semiconductor device according to claim 1, wherein the first emitter electrode and the second collector electrode are linearly connected to each other. 5. The semiconductor device according to claim 1, wherein the first emitter electrode and the second collector electrode are both connected to the same output bus bar via a conductor block.

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