阅读说明：本技术 半导体功率模块 (Semiconductor power module ) 是由 谷昌和 高滨修一 于 2020-10-22 设计创作，主要内容包括：本发明的半导体功率模块通过抑制流过各半导体元件的电流偏差,从而减小半导体元件的尺寸。包括：用于将第一电极(3)与第一外部电部件进行连接的电极端子(4a、4b)；与多个半导体元件(2a～2d)的上表面相接合的第二电极(5)；以及用于将第二电极(5)与第二外部电部件进行连接的第二电极延伸部(5a),将从电极端子(4a、4b)到半导体元件(2a～2d)为止的第一电极(3)中的电流路径长度、与从半导体元件(2a～2d)到第二电极端子部(5b)为止的第二电极(5)中的电流路径长度之和设计为在多个半导体元件(2a～2d)中成为相同。(The semiconductor power module of the present invention reduces the size of the semiconductor elements by suppressing variations in the current flowing through each semiconductor element. The method comprises the following steps: electrode terminals (4a, 4b) for connecting the first electrode (3) with a first external electrical component; a second electrode (5) bonded to the upper surfaces of the plurality of semiconductor elements (2 a-2 d); and a second electrode extension part (5a) for connecting the second electrode (5) and a second external electrical component, wherein the sum of the current path length in the first electrode (3) from the electrode terminals (4a, 4b) to the semiconductor elements (2 a-2 d) and the current path length in the second electrode (5) from the semiconductor elements (2 a-2 d) to the second electrode terminal part (5b) is designed to be the same in the plurality of semiconductor elements (2 a-2 d).)

1. A semiconductor power module comprising:

a first electrode;

a plurality of semiconductor elements connected in parallel with each other and bonded to an upper surface of the first electrode;

an electrode terminal for connecting the first electrode with a first external electrical component;

a second electrode bonded to upper surfaces of the plurality of semiconductor elements;

a second electrode extension for connecting the second electrode with a second external electrical component;

a signal pad provided to the semiconductor element; and

a signal terminal connected to the signal pad by a wire, the semiconductor power module being characterized in that,

in each of the plurality of semiconductor elements, a sum of a current path length in the first electrode from the electrode terminal to the semiconductor element and a current path length in the second electrode from the semiconductor element to a second electrode terminal portion is equal to each other.

2. The semiconductor power module of claim 1,

by adjusting the shape and size of the slit portions provided on both sides of the second electrode extension portion, the sum of the current path length in the first electrode from the electrode terminal to the semiconductor element and the current path length in the second electrode from the semiconductor element to the second electrode terminal portion becomes the same in each of the plurality of semiconductor elements.

3. The semiconductor power module according to claim 1 or 2,

the electrode terminal and the second electrode extension portion are drawn in the same direction, and the signal terminal is drawn in a direction opposite to the direction in which the electrode terminal and the second electrode extension portion are drawn.

4. The semiconductor power module according to any one of claims 1 to 3,

the electrode terminals are composed of two members, and the two electrode terminals are disposed at positions symmetrical to each other centering on the second electrode.

5. The semiconductor power module according to any one of claims 1 to 4,

at least one of the semiconductor elements is mounted with a temperature detection sensor.

6. The semiconductor power module according to any one of claims 1 to 4,

the thermistor is mounted on an upper surface of at least one of the semiconductor elements or an upper surface of the second electrode.

7. The semiconductor power module according to any one of claims 1 to 6,

at least one of the semiconductor elements is mounted with a current detection sensor.

8. The semiconductor power module according to any one of claims 1 to 4,

at least one of the semiconductor elements is mounted with a current detection sensor, and at least one of the semiconductor elements is mounted with a temperature detection sensor,

the semiconductor element to which the temperature detection sensor is attached and the semiconductor element to which the current detection sensor is attached are disposed on opposite sides opposite to each other across a center line of the second electrode.

9. The semiconductor power module according to any one of claims 1 to 8,

the wire is arranged orthogonal to a direction of current flowing through the second electrode.

10. The semiconductor power module according to any one of claims 1 to 9,

the signal pad is disposed opposite to an outer periphery of the first electrode located closest to the semiconductor element.

11. The semiconductor power module according to any one of claims 1 to 10,

the structural member of the semiconductor element is sealed by transfer molding.

12. The semiconductor power module according to any one of claims 1 to 11,

the first electrode has a structure composed of a copper-ceramic-copper layer.

13. A semiconductor power module in which a first semiconductor power module and a second semiconductor power module are connected to each other,

the first semiconductor power module includes:

a first electrode;

a plurality of semiconductor elements connected in parallel with each other and bonded to an upper surface of the first electrode;

an electrode terminal for connecting the first electrode with a first external electrical component;

a second electrode bonded to upper surfaces of the plurality of semiconductor elements;

a second electrode extension for connecting the second electrode with a second external electrical component;

a signal pad provided to the semiconductor element; and

a signal terminal connected to the signal pad by a wire,

the second semiconductor power module includes:

a fifth electrode;

a plurality of semiconductor elements connected in parallel to each other and bonded to an upper surface of the fifth electrode;

a third electrode terminal for connecting the fifth electrode with the second external electrical component; and

a fourth electrode bonded to the upper surfaces of the plurality of semiconductor elements and having two branch portions for connection with the first external electrical component,

the electrode terminal in the first semiconductor power module is adjacent to the branch portion in the second semiconductor power module in an opposing manner, and

the second electrode extension in the first semiconductor power module is connected at one point with the third electrode terminal in the second semiconductor power module.

14. The semiconductor power module of claim 13,

in each of the plurality of semiconductor elements, a sum of a current path length in the first electrode from the electrode terminal to the semiconductor element and a current path length in the second electrode from the semiconductor element to a second electrode terminal portion becomes equal to each other, and

in each of the plurality of semiconductor elements, a sum of a current path length in the fourth electrode from the branch portion to the semiconductor element and a current path length in the fifth electrode from the semiconductor element to the third electrode terminal is equal to each other.

15. The semiconductor power module of claim 14,

by adjusting the shape and size of the slit portions provided on both sides of the second electrode extension portion, the sum of the current path length in the first electrode from the electrode terminal to the semiconductor element and the current path length in the second electrode from the semiconductor element to the second electrode terminal portion becomes the same in each of the plurality of semiconductor elements, and the sum of the current path lengths in the first electrode from the electrode terminal to the semiconductor element and the current path length in the second electrode from the semiconductor element to the second electrode terminal portion becomes the same, and

by adjusting the shape and size of the slit portion provided in the fourth electrode, the sum of the current path length in the fourth electrode from the branch portion to the semiconductor element and the current path length in the fifth electrode from the semiconductor element to the third electrode terminal becomes equal in each of the plurality of semiconductor elements.

16. The semiconductor power module according to any one of claims 13 to 15,

the electrode terminal and the second electrode extension portion are drawn in the same direction, and the signal terminal is drawn in a direction opposite to the direction in which the electrode terminal and the second electrode extension portion are drawn.

17. The semiconductor power module according to any one of claims 13 to 16,

the electrode terminals are composed of two members, and the two electrode terminals are disposed at positions symmetrical to each other centering on the second electrode.

18. The semiconductor power module according to any one of claims 13 to 17,

at least one of the semiconductor elements is mounted with a temperature detection sensor.

19. The semiconductor power module according to any one of claims 13 to 17,

the thermistor is mounted on an upper surface of at least one of the semiconductor elements or an upper surface of the second electrode.

20. The semiconductor power module according to any one of claims 13 to 19,

at least one of the semiconductor elements is mounted with a current detection sensor.

21. The semiconductor power module according to any one of claims 13 to 17,

at least one of the semiconductor elements is mounted with a current detection sensor, and at least one of the semiconductor elements is mounted with a temperature detection sensor,

the semiconductor element to which the temperature detection sensor is attached and the semiconductor element to which the current detection sensor is attached are disposed on opposite sides opposite to each other across a center line of the second electrode.

22. The semiconductor power module according to any one of claims 13 to 21,

the wire is arranged orthogonal to a direction of current flowing through the second electrode.

23. The semiconductor power module according to any one of claims 13 to 22,

the signal pad is disposed opposite to an outer periphery of the first electrode located closest to the semiconductor element.

24. The semiconductor power module according to any one of claims 13 to 23,

the structural member of the semiconductor element is sealed by transfer molding.

25. The semiconductor power module according to any one of claims 13 to 24,

the first electrode has a structure composed of a copper-ceramic-copper layer.

26. The semiconductor power module according to any one of claims 13 to 25,

the fifth electrode has a structure composed of a copper-ceramic-copper layer.

Technical Field

The present application relates to semiconductor power modules.

Background

In a SEMICONDUCTOR power module including a plurality of SEMICONDUCTOR elements, when a METAL-OXIDE-SEMICONDUCTOR FIELD EFFECT TRANSISTOR (MOSFET) is used as an example of the SEMICONDUCTOR element, a voltage is always applied between a drain and a source, and a voltage is applied between a gate and the source as necessary in order to control switching operations of on and off. In the semiconductor element, the drain side of the lower surface is joined to a metal electrode having good electrical conductivity and thermal conductivity by solder or the like, and the source side of the upper surface is also joined to a metal electrode having good electrical conductivity and thermal conductivity by solder or the like. The gate of the semiconductor device has a pad on the upper surface of the device, and the source of the semiconductor device also has a pad on the upper surface of the device. Depending on the semiconductor device, there is also a semiconductor device including a temperature detection pad and a current detection pad in the vicinity of a pad. The signal terminals serving as an interface between the pad and the outside are generally connected by wire bonding, and are sealed together with electrodes and the like by epoxy resin, silicone resin, or the like except for a connection portion with the outside.

Patent document 1 discloses a power module including a chip set including a plurality of semiconductor chips and a chip set input terminal for inputting a signal transmitted to the chip set. The chipset input terminal is provided at a position overlapping with the chipset in a plan view. Each of the plurality of semiconductor chips includes a switching element including a gate electrode formed on the semiconductor substrate, and an electrode terminal formed on the semiconductor substrate and electrically connected to the gate electrode. The electrode terminal is arranged closer to the chipset input terminal side than the center of the semiconductor substrate in a plan view, and the electrode terminal is electrically connected to the chipset input terminal.

Further, the comparison document 1 discloses that the connection resistance when the module input terminal and each of the chip group input terminals of the plurality of chip groups are connected by the connection member can be adjusted to be close to each other between the four chip groups. Therefore, since the impedances between the module input terminal and each of the chipset input terminals of the plurality of chipsets can be adjusted to be close to each other, the input waveform of the gate signal to be transmitted to each of the chipset input terminals of the plurality of chipsets can be prevented or suppressed from being disturbed.

Documents of the prior art

Patent document

Patent document 1: international patent publication No. 2015/128975

Disclosure of Invention

Technical problem to be solved by the invention

In recent years, MOSFETs using silicon carbide (SiC) having a wide band gap have been used as elements replacing silicon (Si) IGBTs (INSULATED GATE BIPOLAR TRANSISTORs) in vehicle-mounted drive motors. As described in patent document 1, the SiC semiconductor substrate has more crystal defects than Si. Therefore, when the size of the semiconductor element is increased, the probability of including defects is high, and the manufacturing productivity is deteriorated. To avoid this, a plurality of smaller-sized semiconductor elements are used in parallel.

In this case, it is necessary to suppress the disturbance of the input waveform of the gate signal due to the impedance variation between the input terminal and the gate electrode as described in patent document 1. More importantly, the variation in current flowing between the drain and the source of the semiconductor element is suppressed. Among the plurality of semiconductor elements, the semiconductor element through which the largest current flows has a limitation in junction temperature, and the power that can be converted by the power module is limited by this limitation in temperature. In other words, when the necessary output is determined, the semiconductor element having the largest current flow needs to be increased in size so that the junction temperature does not exceed the allowable value. This need becomes significant when the variation in current cannot be suppressed. Since semiconductor elements of the same size are generally used in the same power module, there is a problem that a plurality of large semiconductor elements are arranged, and the size and cost are increased.

In addition, in the case of using the synchronous rectification method, although a parasitic diode is sometimes used in the MOSFET, there is a restriction due to an allowable current density when the diode is energized, and in a semiconductor element through which a maximum current flows, it is necessary to determine the size of the semiconductor element so as to satisfy the restriction. Therefore, it becomes important to suppress the variation in current.

The present application discloses a technique for solving the above-described problems, and an object of the present invention is to suppress variations in currents flowing through semiconductor elements, thereby reducing the size of the semiconductor elements and achieving a reduction in size and cost of a semiconductor power module.

Technical scheme for solving technical problem

The semiconductor power module disclosed in the present application includes:

a first electrode;

a plurality of semiconductor elements connected in parallel with each other and bonded to an upper surface of the first electrode;

an electrode terminal for connecting the first electrode with a first external electrical component;

a second electrode bonded to upper surfaces of the plurality of semiconductor elements,

a second electrode extension for connecting the second electrode with a second external electrical component;

a signal pad provided to the semiconductor element; and

a signal terminal connected to the signal pad by a wire,

in each of the plurality of semiconductor elements, a sum of a current path length in the first electrode from the electrode terminal to the semiconductor element and a current path length in the second electrode from the semiconductor element to a second electrode terminal portion is equal to each other.

Further, another semiconductor power module disclosed in the present application is a semiconductor power module in which a first semiconductor power module and a second semiconductor power module are connected,

the first semiconductor power module includes:

a first electrode;

a plurality of semiconductor elements connected in parallel with each other and bonded to an upper surface of the first electrode;

an electrode terminal for connecting the first electrode with a first external electrical component;

a second electrode bonded to upper surfaces of the plurality of semiconductor elements,

a second electrode extension for connecting the second electrode with a second external electrical component;

a signal pad provided to the semiconductor element; and

a signal terminal connected to the signal pad by a wire,

the second semiconductor power module includes:

a fifth electrode;

a plurality of semiconductor elements connected in parallel to each other and bonded to an upper surface of the fifth electrode;

a third electrode terminal for connecting the fifth electrode with the second external electrical component; and

a fourth electrode bonded to the upper surfaces of the plurality of semiconductor elements and having two branch portions for connection with the first external electrical component,

the electrode terminal in the first semiconductor power module is adjacent to the branch portion in the second semiconductor power module in an opposing manner, and,

the second electrode extension in the first semiconductor power module is connected at one point with the third electrode terminal in the second semiconductor power module.

Effects of the invention

According to the semiconductor power module disclosed in the present application, variations in current flowing through each semiconductor element can be suppressed. As a result, the size of the semiconductor element can be reduced, and the semiconductor power module can be downsized and can be manufactured at low cost.

Drawings

Fig. 1 is a circuit diagram showing an inverter circuit as an example of a power conversion device.

Fig. 2 is a plan view showing the structure of an upper arm in the semiconductor power module according to embodiment 1.

Fig. 3 is a plan view showing the structure of the semiconductor power module according to embodiment 1.

Fig. 4 is a plan view showing the structure of the semiconductor power module according to embodiment 1.

Fig. 5 is a sectional view taken along line a-a of fig. 2.

Fig. 6 is a plan view showing the structure of a lower arm in the semiconductor power module according to embodiment 2.

Fig. 7 is a sectional view taken along line B-B of fig. 6.

Fig. 8 is a plan view of a state in which the semiconductor power module constituting the upper arm and the semiconductor power module constituting the lower arm according to embodiment 2 are connected to each other.

Detailed Description

Embodiment 1.

The power conversion device is a device having a switching circuit for controlling power, and corresponds to a power conversion device such as a motor driving inverter mounted on an electric vehicle, a boost converter for converting a low voltage into a high voltage, and an electric power module such as a charger connected to an external power supply device to charge a vehicle battery. Fig. 1 is a circuit diagram showing an inverter circuit as an example of a power conversion device. In the figure, the motor drive inverter is composed of three phases of U-phase, V-phase, and W-phase, and each phase is composed of two arms of upper arm 101 and lower arm 102, two arms of upper arm 103 and lower arm 104, and two arms of upper arm 105 and lower arm 106.

Each arm is composed of a power module and has a semiconductor element therein. The semiconductor device corresponds to a MOSFET, an IGBT, or a diode, and a next-generation semiconductor such as silicon carbide or gallium nitride can be used as a base material in addition to silicon. As the electric power module is required to have a large output as the electric vehicle is driven, a plurality of semiconductor elements are connected in parallel to allow a large current to flow therethrough. In order to ensure the production yield of silicon carbide and gallium nitride, each arm has a structure in which a plurality of semiconductor elements having small outer dimensions are connected in parallel.

Next, the structure of the power module will be explained. Fig. 2 is a plan view showing the structure of an upper arm in the semiconductor power module, and shows, for example, a parallel connection structure of four semiconductor elements constituting the switching element Q1 of the upper arm 101 of fig. 1. The plurality of semiconductor elements 2a to 2d are bonded to the first electrode 3 by solder or silver firing. As the plate-shaped first electrode 3, copper having excellent electrical conductivity and heat dissipation is often used. Since the power module generates a large amount of heat, it is necessary to cool the power module, and the first electrode 3 is joined to a cooler (not shown) made of copper or aluminum having a high thermal conductivity. As the joining member, a heat-dissipating insulating adhesive sheet (not shown) or the like is used. The power module may be pressed against the cooler side by a spring in order to ensure adhesion to the cooler by using the heat dissipating insulating sheet and the heat dissipating grease.

The lower surfaces of the semiconductor elements 2a to 2d (here, referred to as MOSFETs) bonded to the first electrode 3, that is, the surfaces bonded to the first electrode 3 are drain-side surfaces, and electrode terminals 4a and 4b connected to the drain are bonded to the first electrode 3 with solder or the like. The upper surfaces of the semiconductor elements 2a to 2d are source sides, and the plate-like second electrode 5 is joined to the sources 300 of the plurality of semiconductor elements 2a to 2 d. Solder or liquid-like diffusion bonding material is used as the bonding material. Here, the current paths of all the semiconductor elements 2a to 2d are configured to flow from the electrode terminal 4a and the electrode terminal 4b to the second electrode terminal portion 5b via the drains and sources 300 of the semiconductor elements 2a to 2 d.

In each of the semiconductor elements 2a to 2d, the sum of the length of the current path in the second electrode 5 from the second electrode terminal portion 5b to the source 300 of the semiconductor element 2a to 2d and the length of the current path in the first electrode 3 from the drain (not shown) of the semiconductor element 2a to 2d to the electrode terminal 4a, 4b is adjusted to be equal in each of the semiconductor elements 2a, 2b, 2c, 2 d. The adjustment is performed by adjusting the shape of the second electrode 5, but is mainly performed by adjusting the shape and size of the slit portions 5c provided on both sides of the second electrode extension portion 5 a. This can suppress current variation when the parasitic diode of the MOSFET is energized.

It is desirable that the length of the current path of the second electrode 5 from the second electrode terminal portion 5b to the source 300 of each of the semiconductor elements 2a, 2b, 2c, 2d is uniform among the semiconductor elements 2a to 2 d. However, since complete equalization cannot be achieved under the above conditions, the adjustment is made to be as uniform as possible. This adjustment is performed by adjusting the shape and size of the slit portion 5 c. And, the chip spacing is reduced (near the center portion), thereby reducing the difference in the length of the current path of the second electrode 5. That is, the intervals of the mounting positions of the semiconductor elements 2a, 2b, 2c, 2d are reduced. The intervals between the mounting positions of the semiconductor elements 2a, 2b, 2c, 2d are preferably 5mm or less. This can suppress current variation when the MOSFET is energized clockwise.

The two electrode terminals 4a, 4b connected to the drain are arranged at positions symmetrical to each other with the second electrode 5 as the center, and no difference in electrical impedance is generated between the semiconductor elements 2a, 2b and the semiconductor elements 2c, 2d in fig. 2. The four semiconductor elements 2a to 2d are bonded to the first electrode 3, and the signal pads 110 of these semiconductor elements 2a to 2d are disposed so as to face the outer periphery 3A of the first electrode 3 located closest to the semiconductor elements 2a to 2 d. For example, in fig. 2, the signal pad 110b of the semiconductor element 2b is disposed at a position closest to the outer periphery 3A of the first electrode 3 in the semiconductor element 2 b. With this configuration, the signal pads 110 of the semiconductor elements 2a to 2d are arranged in the vicinity of the signal terminals 6, and the length of the lead wiring connecting the signal pads 110 and the signal terminals 6(6a to 6j) is shortened. Therefore, the resistance becomes small in the path through which the signal is transmitted, and the signal transmission becomes fast, so that the controllability is improved.

The electrode terminals 4a, 4b are connected to the positive electrode of a battery (first external electrical component), and the second electrode terminal portion 5b is connected to a motor (second external electrical component). The upper surfaces of the semiconductor elements 2a, 2b, 2c, and 2d are provided with signal pads 110. The signal pads include a gate pad and a source pad to which a voltage is applied to control on/off of the semiconductor elements 2a, 2b, 2c, and 2 d. In addition, in the present embodiment, a temperature detection pad and a current detection pad are provided. The temperature detection is performed by the semiconductor element 2b, and the current detection is performed by the semiconductor element 2 c. In the semiconductor elements 2a, 2b, and 2d in which current is not detected, the current detection pad is connected to the signal terminal 6 by the wire 201 so as to have the same potential as the source 300. Further, the semiconductor power module is provided with a signal terminal 6, specifically, gate signal terminals 6a, 6c, 6h, 6j, source signal terminals 6b, 6d, 6g, 6i, a temperature detection signal terminal 6e, and a current detection signal terminal 6f, at one end.

The semiconductor element 2b on which the temperature detection sensor is mounted and the semiconductor element 2c on which the current detection sensor is mounted are disposed on opposite sides opposite to each other with respect to the center line of the second electrode 5. The temperature and the current are detected by the semiconductor elements 2b and 2c which are located at a short distance from the lead-out portions of the signal terminals 6a to 6 j. This reduces the resistance value of the signal terminal, and the signal is transmitted more quickly, thereby improving the accuracy of detecting the temperature and the current.

As described above, temperature detection may be performed by providing a detection structure in a semiconductor element or by disposing a thermistor in the vicinity of the semiconductor element. In fig. 3, the thermistor 6G is mounted by bonding to the upper surface of the second electrode 5 with an adhesive material or solder. In fig. 4, the thermistor 6G and the upper surface of the semiconductor element 2b may be attached by bonding them with an adhesive or solder.

The lead wire 201 connecting the signal pad 110 and the signal terminal 6 is arranged substantially orthogonal to the direction of the current flowing through the second electrode 5 shown by the straight arrow in fig. 2, and is not easily affected by the magnetic field generated by the current flowing through the second electrode 5.

By performing temperature detection within one module, temperature detection can be performed with higher accuracy than performing temperature detection at one location for a plurality of modules. Therefore, the allowable value with respect to the allowable junction temperature of the semiconductor element can be reduced.

Even in the current detection, since the currents flowing through the arms are different, the current is detected for each arm and the overcurrent is protected, so that the quality of the product can be ensured.

The electrode terminals 4a and 4b are led out in the same direction as the second electrode extension portion 5a, and the signal terminals 6a to 6j connected to the signal pads 110 of the semiconductor elements 2a to 2d are led out in the direction opposite to the above direction. A large current of several tens to several hundreds a flows through the electrode terminals 4a and 4b and the second electrode extension 5a, for example. On the other hand, a minute current of several mA flows through the signal terminals 6a to 6 j. Since the signal terminals 6a to 6j can be provided at positions spaced apart from the electrode terminals 4a and 4b and the second electrode extension portion 5a, the influence of electromagnetic noise from the electrode terminals 4a and 4b and the second electrode extension portion 5a is reduced, and malfunction can be prevented.

The signal terminals are concentrated on the left side of fig. 2, and the terminals of a so-called power system through which a large current flows are concentrated on the right side, so that the connection between the control board (not shown) and the bus bar (not shown) is facilitated, and the shapes of the control board and the bus bar can be simplified, thereby contributing to miniaturization. Further, since the signal terminal is located at a position away from the power terminal through which a large current flows, noise mixed in the signal of the signal terminal is reduced, temperature detection accuracy and current detection accuracy are improved, and a malfunction in the switching operation is suppressed.

Fig. 5 is a sectional view taken along line a-a of fig. 2. Each member described above is integrally molded with the sealing resin 7. The electrode terminals 4a and 4b, the second electrode 5, and the signal terminal 6 are formed of one member called a lead frame before molding, and the terminals are connected to each other. After the molding, cutting, so-called tie bar cutting, is performed to bend the vicinity of the terminal as necessary, thereby facilitating connection in a subsequent step. The first electrode 3 and the like structural members are sealed by transfer molding. Productivity can be improved by using transfer molding. As the sealing resin 7, an epoxy resin can be used. The lower surface of the first electrode 3, that is, the surface of the first electrode 3 not bonded to the semiconductor elements 2a to 2d is exposed after molding because it is a heat radiation surface. The power module is joined to the cooler as described above, and the sealing resin 7 is provided with the convex portions 7a and 7b for positioning the power module and the cooler. In fig. 5, a bonding material 8 is provided on the lower side of the semiconductor elements 2c and 2d, and a bonding agent 9 is provided on the upper side.

In the semiconductor power module having the plurality of semiconductor elements 2a to 2d according to the present embodiment, the wiring lengths from the input terminal portions of the electrodes bonded to the semiconductor elements 2a to 2d are made uniform. This can suppress variations in the current flowing through each of the semiconductor elements 2a to 2 d. As a result, the semiconductor elements 2a to 2d can be reduced in size, and the semiconductor power module can be reduced in size and cost.

Embodiment 2.

Fig. 6 is a plan view showing the structure of the lower arm in the semiconductor power module according to embodiment 2, and shows, for example, a parallel connection structure of four semiconductor elements constituting the switching element Q2 of the lower arm 102 in fig. 1. Fig. 7 is a sectional view taken along line B-B of fig. 6. In the configuration of the lower arm 1b, the extension portion of the fourth electrode 12 connected to the source 301 of the semiconductor elements 22a to 22d is branched into two, and has branch portions 12a and 12b, and the branch portions 12a and 12b are connected to the negative electrode of the battery. The third electrode terminal 11 is connected to the upper surface of the heat-dissipating insulating substrate 10 (fifth electrode), that is, the same surface as the surface to which the semiconductor elements 22a to 22d are bonded. The third electrode terminal 11 is connected to the second electrode terminal portion 5b, which is the source potential of the upper arm, and the motor. Fig. 8 is a plan view showing a state in which the semiconductor power module (first semiconductor power module) constituting the upper arm 1a and the semiconductor power module (second semiconductor power module) constituting the lower arm are connected.

In the lower arm 1b, in contrast to the upper arm 1a shown in fig. 2, the branch portions 12a and 12b, which are arranged to have the source potential, are sandwiched around the third electrode terminal 11, which is the drain potential, so that no resistance difference occurs. That is, as in embodiment 1, the sum of the length of the current path in the electrode from the branch portion 12a or 12b to the source 301 of each of the semiconductor elements 22a to 22d in each of the semiconductor elements 22a to 22d and the length of the current path in the fifth electrode (heat radiation insulating substrate 10) from the drain of the semiconductor element 22a to 22d to the third electrode terminal 11 is made the same in each of the semiconductor elements 22a to 22d, thereby eliminating the resistance difference.

The adjustment is performed by adjusting the shape of the fourth electrode 12 as in the case of embodiment 1, but is mainly performed by adjusting the shape and size of the slit portion 12c provided in the fourth electrode 12.

As shown in fig. 8, the second electrode terminal portion 5b of the first semiconductor power module constituting the upper arm 1a and the third electrode terminal 11 of the second semiconductor power module constituting the lower arm 1b are connected at one point, whereby the parasitic inductance from the electrode terminals 4a and 4b to the branch portions 12a and 12b can be suppressed to a low level. That is, the second electrode terminal portion 5b of the upper arm 1a and the third electrode terminal 11 of the lower arm 1b can be directly connected without using another member, and therefore parasitic inductance can be suppressed to be low.

The surge voltage is determined by the product of the parasitic inductance and the switching speed, and the switching speed needs to be adjusted so that the surge voltage does not exceed the withstand voltage of the semiconductor element. When the parasitic inductance becomes small, the switching speed can be increased, and thus the switching loss of the semiconductor element can be reduced.

In the present embodiment, the electrode terminals 4a, 4b in the first semiconductor power module 1a and the branch parts 12a, 12b in the second semiconductor power module 1b are adjacent in an opposing manner, and the second electrode extension part 5a in the first semiconductor power module 1a and the third electrode terminal 11 in the second semiconductor power module 1b are connected at one point.

In fig. 7, in this embodiment, a heat-dissipating insulating substrate 10 is used instead of the first electrode 3 in embodiment 1. The heat sink insulating substrate 10 is generally a structure (composite material) composed of a copper-ceramic-copper layer, and the drains of the semiconductor elements 22a to 22d are insulated from the cooler by ceramic. Therefore, the bonding material between the power module and the cooler may be formed of a conductive member such as solder or silver paste. It is desirable that the members disposed under the semiconductor elements of the upper arm 1a and the lower arm 1b are identical in advance from the viewpoint of productivity. In addition, as the first electrode shown in embodiment 1, a structure (composite material) composed of a copper-ceramic-copper layer may be used.

Further, although the motor is described as an object to which the power module is connected, it is effective in high-frequency driving even in SiC having a small loss at the time of switching, and it is effective to reduce the size of the inductor even when this embodiment is used as a boost inductor.

The number, size, material, and the like of the other constituent members can be appropriately changed.

Although various exemplary embodiments and examples have been described in the present application, the various features, modes, and functions described in 1 or more embodiments are not limited to the application to specific embodiments, and may be applied to the embodiments alone or in various combinations.

Therefore, countless modifications not shown by way of example can be conceived within the technical scope disclosed in the present application. For example, the case where at least one component is modified, added, or omitted, and the case where at least one component is extracted and combined with the components of other embodiments are included.

Description of the reference symbols

1a semiconductor power module,

1b a semiconductor power module,

2a to 2d semiconductor elements,

3a first electrode,

4a, 4b electrode terminals,

5a second electrode,

5a second electrode extension,

5b a second electrode terminal portion,

5c a slit portion,

6 signal terminals,

A 6G thermistor,

10 a heat-dissipating insulating substrate,

11 the 3 rd electrode terminal,

12a, 12b branch parts,

201 conducting wires.