JP5709161B2 - Power semiconductor module - Google Patents

Description

  The present invention relates to a highly reliable power semiconductor module that is small and has a high mounting density.

  Currently, in the technical field of power semiconductor modules, it is desired to mount power semiconductor elements and various electronic components (capacitors, resistors, etc.) at high density and to reduce the size. The power semiconductor module is used in an in-vehicle motor drive or the like, and handles a large current exceeding 50 A. Therefore, it is desired that the power semiconductor module has a large heat dissipation performance as well as downsizing.

  Further, as the performance of the power semiconductor element is improved and the switching speed is increased, destruction of the element due to a surge voltage at the time of switching has become a problem (see Patent Document 1). In order to suppress the surge voltage, it is known that it is necessary to make the wiring short and wide to suppress the inductance due to the wiring (see Patent Document 1).

  Further, in the power semiconductor module, in order to suppress a transient high voltage generated from the inductance in the circuit when the switch is cut off, a protection circuit is provided to solve the problem. For example, a snubber circuit is known as the protection circuit. A typical example is a snubber circuit in which a capacitor (also called a snubber capacitor) and a resistor are connected in series.

  In a power semiconductor module, a sensor is provided in the module in order to detect abnormality of the module. For example, in Patent Document 2 (see paragraph 29 and the like), a sensor is provided in the power semiconductor module. Japanese Patent Application Laid-Open No. 2004-228561 discloses that the control unit detects abnormality (overcurrent, overvoltage, overtemperature, etc.) and stops the switching operation of the power semiconductor based on sensing information from the sensor.

JP 2010-177453 A JP 2010-35346 A

  Conventionally, a power semiconductor module has a temperature of 200 ° C. during operation, and thus there has been a problem in that an electrode formed on a ceramic substrate is peeled off or a wire bonding is disconnected by a thermal cycle. Therefore, the temperature, voltage, current, and the like of the power semiconductor module are measured, but only one temperature sensor, voltage sensor, and current sensor are mounted on the entire module. This makes it impossible to know the state of individual power semiconductor elements in the module.

  Therefore, it is considered that high-precision control is possible by measuring individual semiconductor elements or measuring temperature at each position. However, when each sensor is arranged in each power semiconductor element, there is a problem that it requires an area and cannot be miniaturized.

  Further, it is desirable that the protection circuit for suppressing the transient high voltage generated from the inductance in the circuit when the switch is cut off is as close as possible to the power semiconductor element. Therefore, conventionally, a power semiconductor element and a protection circuit made up of a capacitor and a resistor are mounted on the same substrate. However, it is disadvantageous for increasing the density by the area occupied by the snubber capacitor and the resistor.

  Conventionally, a power semiconductor element, a snubber capacitor, and a resistor are connected by wire bonding. Therefore, there is a problem that stray inductance is generated by the wire and the surge voltage is increased.

  The present invention is intended to solve these problems, and aims to increase the mounting density of a power semiconductor element, a protective circuit component including a snubber capacitor and a resistor, and to realize a miniaturized power semiconductor module. . It is another object of the present invention to realize a power semiconductor module that eliminates wire bonding. In a power semiconductor module including a plurality of power semiconductor elements and a plurality of protection circuit components, an object is to grasp the operating state of each power semiconductor element and prevent a failure of the power semiconductor module.

  The present invention has the following features in order to achieve the above object.

  The apparatus according to the present invention relates to a power semiconductor module including a plurality of power semiconductor elements for switching current, a protection circuit element for protecting the power semiconductor elements, and a lead frame. In the power semiconductor module of the present invention, a power semiconductor element is directly electrically connected to one surface of the lead frame, and the protection circuit element is opposed to the power semiconductor element on the other surface of the lead frame. One or more of a temperature sensor, a current sensor, and a voltage sensor that are directly electrically connected and measure the power semiconductor element are installed in each power semiconductor element. In the power semiconductor module of the present invention, the current sensor is provided at a current terminal electrically connected to an electrode of the power semiconductor element, and the current terminal is connected to a lead frame. In the power semiconductor module of the present invention, it is preferable that the temperature sensor is disposed in a gap generated by the power semiconductor element, the protection circuit element, and the current terminal. The temperature sensor or the voltage sensor may be an integral part of the protection circuit element. Specifically, the protection circuit element includes a snubber capacitor and a resistor. The power semiconductor module of the present invention preferably has a heat dissipation mechanism, and the power semiconductor element and the current terminal are in contact with a ceramic substrate and are thermally connected to the heat dissipation mechanism. The protective circuit element is preferably in contact with the ceramic substrate and thermally connected to the heat dissipation mechanism.

  According to the present invention, the power semiconductor element is directly electrically connected to one surface of the lead frame, and the protection circuit element is directly electrically connected to the other surface of the lead frame, so that both surfaces of the lead frame can be used for mounting. The mounting density can be increased and the size can be reduced. In addition, by arranging protective circuit components such as resistors and capacitors on both sides of the lead frame and facing each other, wiring can be shortened without using wire bonding, reducing stray inductance and suppressing surge voltage can do. In addition, in a power semiconductor module comprising a plurality of power semiconductor elements and a plurality of protection circuit components, a sensor for measuring each power semiconductor element is arranged in the vicinity of each power semiconductor element, so that the operating status of each power semiconductor element To prevent power semiconductor module failures. Since one or more of the voltage sensor, current sensor, and temperature sensor can measure individual power semiconductor elements, it is possible to improve the accuracy of power semiconductor module measurement and improve reliability. To do.

  By using an integral part in which the snubber capacitor and the resistor are integrated, the mounting process is simplified, the durability of the electronic component is improved, and the floating inductor is reduced. By using an integrated component in which the temperature sensor and the voltage sensor are integrated with the RC snubber circuit component, it is possible to further simplify the mounting process, improve the durability of the electronic component, and reduce the floating inductor.

The figure which shows the power semiconductor module of this invention. The figure explaining the power semiconductor module of this invention.

  The power semiconductor module of the present invention is applied as a switching device to a switching power supply, an air conditioner, an uninterruptible power supply (UPS), an inverter of an electric vehicle, a hybrid vehicle, and the like. For example, it is used for an in-vehicle motor drive and an ECU (engine control unit). The power semiconductor module of the present invention includes a power semiconductor element that opens and closes a plurality of currents, a plurality of protection circuit components, a plurality of sensors, and a lead frame. The sensor is a sensor that measures current, voltage, temperature, and the like of each power semiconductor element. Based on sensor information (temperature information, current information, voltage information) from each sensor, a control circuit such as a microcomputer grasps the operating state of the power semiconductor element and performs control to prevent the power semiconductor module from being broken. When over-temperature detection, over-voltage detection, or over-current detection is performed, the power semiconductor element exhibiting an abnormality is protected from over-temperature and over-voltage by, for example, stopping switching.

(First embodiment)
A first embodiment of the present invention will be described below with reference to FIG. FIG. 1 is a schematic structural diagram of a power semiconductor module. FIG. 1A is a side sectional view showing the entire sectional structure including a heat dissipation structure such as a heat sink. FIG. 1B is a top view for explaining the relationship among the power semiconductor element, the lead frame, the current terminal, and the electrode in the power semiconductor module of FIG. FIG. 1B illustrates the arrangement of the power semiconductor element, the lead frame, the current terminals, and the electrodes in correspondence with FIG. 1A.

  The power semiconductor module according to the present embodiment includes a plurality of power semiconductor elements, a plurality of protection circuit integrated components, and a plurality of sensors. FIG. 1 shows one unit including one power semiconductor element, one protection circuit component, and a sensor. A power semiconductor module consists of a set of two or more units. Each unit is fixed to a lead frame and a ceramic substrate, and is further thermally connected to a common or individual heat dissipation structure (metal heat dissipation plate, heat sink).

  1 includes a power semiconductor element 1, a collector electrode 11 of the element, a gate electrode 12, a source electrode 13, a protection circuit component 2, electrodes 21 and 22 of the component, and a temperature sensor 23. A temperature sensor signal extraction terminal 24, a voltage sensor signal extraction terminal 25, a current terminal 3, an electrode 31 of the current terminal, a current sensor (coil shape) 32, a current sensor signal extraction terminal 33, and a lead frame. 51, 52, ceramic substrates 71, 72, metal heat sinks 81, 82, and heat sinks 91, 92.

  The collector electrode 11 of the power semiconductor element 1 is directly electrically connected to one surface of the lead frame 51 without using wire bonding. For example, it is performed by a connection technology using silver nanoparticles.

  The protective circuit component 2 is directly electrically connected to the other surface of the lead frame 51 (the surface on which the power semiconductor element 1 is not mounted) at a position facing the power semiconductor element 1 without using wire bonding. For example, it is performed by a connection technology using silver nanoparticles. As shown in FIG. 1, the electrode 21 of the protection circuit component 2 is mounted on the lead frame 51, and the other electrode 22 of the protection circuit component is mounted on the lead frame 52.

  A sensor for measuring the power semiconductor element 1 is installed in each power semiconductor element. Here, the reliability is improved by installing all of the temperature sensor 23, the current sensor 32, and the voltage sensor, but any one or more sensors may be installed.

  The current sensor 32 can be provided at the current terminal 3 that is electrically connected to the electrode (source electrode 13) of the power semiconductor element 1. One of the current terminals 3 is electrically connected to the source electrode 13 on the surface facing the collector electrode 11 of the power semiconductor element 1 where the collector electrode 11 is connected to the lead frame 51, and the other is connected to the lead frame 52 with the electrode 31. Electrically connected. In FIG. 1, the current terminal 3 is formed of a member having an L-shaped cross section. More specifically, the member having an L-shaped section includes a plate-shaped portion that is fixed in contact with the ceramic substrate 71 and a rectangular section that is wound with a coil of the current sensor. A known material can be used for the current terminal 3 as a terminal. For example, copper may be used.

  The power semiconductor element 1 is a chip of a SiC semiconductor element. For example, a MOSFET (10A / 1200V) may be used. For example, the size is 3 mm × 3 mm × 0.3 t mm. The operating temperature is as high as ˜150 ° C., further ˜200 ° C. or ˜300 ° C.

  The protection circuit component 2 is preferably an integrated component composed of a snubber capacitor and a resistor. The size of the integrated component is, for example, a length of 10 mm, a width of 4 mm, and a thickness of 3 mm. FIG. 1 shows a diagram of components in which the temperature sensor 23 and the voltage sensor are integrated with the snubber capacitor and the resistor. The signal extraction terminal 24 and the voltage sensor extraction terminal of the temperature sensor 23 are fixed to the ceramic substrate 72 and appropriately connected to wiring on the ceramic substrate. The temperature sensor 23 and the voltage sensor are not necessarily integrated with each other, and may be arranged in the vicinity of the protection circuit component so long as the power semiconductor elements of the same unit are measured.

  As shown in FIG. 1, the temperature sensor 23 is preferably disposed in a gap generated by the power semiconductor element 1, the protection circuit element (component) 2, and the current terminal 3. High-density mounting and high precision of measurement can be achieved.

  As the metal heat sinks 81 and 82, known heat sinks can be used. In the present embodiment, copper (length 15 mm, width 8 mm, thickness 3 mm, etc.) is used.

  The current sensor 32 may be a coil-shaped sensor as illustrated in FIG.

  For the lead frames 51 and 52, a known material can be used as the lead frame. Copper or aluminum is preferred. In the present embodiment, two lead frames each having a length of 10 mm, a width of 5 mm, and a thickness of 1 mm are used for each SiC semiconductor element.

  The ceramic substrates 71 and 72 are made of silicon nitride. A ceramic substrate made of silicon nitride is excellent in thermal conductivity and strength, and has, for example, a thermal conductivity of 80 W / mK and a strength of 800 MPa. In the present embodiment, for example, the length is 15 mm, the width is 8 mm, and the thickness is 0.62 mm.

  The power semiconductor element 1 and the current terminal 3 are disposed in contact with the ceramic substrate 71, and the ceramic substrate 71 is fixed in contact with each other on a mechanism (metal heat radiation plate 81, heat sink 91) suitable for heat radiation.

  The protection circuit component 2 is in contact with the ceramic substrate 72 and fixed to the heat dissipation mechanism (metal heat dissipation plate 82, heat sink 92). Conventionally known materials and structures can be applied to the heat sinks 91 and 92.

The operation of the power semiconductor module of the present embodiment will be described with reference to FIG.
When the current is opened and closed by the power semiconductor element 1, the current (bold arrow) is taken out through the lead frames 51 and 52. At this time, the surge voltage generated at the time of opening and closing the current is suppressed by the protection circuit component 2 including the snubber capacitor and the resistor provided in parallel with the current flow. As shown in FIG. 2, the protection circuit component 2 includes a snubber capacitor and a resistor. The mounting density was increased by mounting the protection circuit component 2 including the snubber capacitor and the resistor at a position facing the power semiconductor element 1 with the lead frame 51 interposed therebetween. Further, since the power semiconductor element 1 and the protection circuit component 2 are directly electrically connected and mounted on both surfaces of the lead frame without using wire bonding, the wiring is minimized, so that the floating inductance is suppressed. Further, the temperature of each power semiconductor element 1 is constantly measured by the temperature sensor. Thereby, when the temperature of the power semiconductor element 1 rises abnormally, the operation of the power semiconductor module can be stopped instantaneously to prevent an accident. In addition, since the current flowing through the current terminal can always be measured by the current sensor, an abnormality in the current can be measured instantaneously, the operation of the power semiconductor module can be stopped, and an accident can be prevented. In addition, as shown in FIG. 2, the voltage of the power semiconductor element 1 can be constantly measured by connecting the lead frame 51 and the lead frame 52 as shown in FIG. You can control.

  In addition, the example shown by the said embodiment etc. was described in order to make invention easy to understand, and is not limited to this form.

  The power semiconductor module of the present invention is applied to a switching power supply, an air conditioner, an uninterruptible power supply (UPS), an inverter of an electric vehicle, a hybrid vehicle, and the like. Furthermore, it can be suitably used for an inverter device, a switching device, and the like of various electric devices constituting the smart grid.

DESCRIPTION OF SYMBOLS 1 Power semiconductor element 11 Collector electrode 12 Gate electrode 13 Source electrode 2 Protection circuit component 22 Electrode 23 Temperature sensor 24 Temperature sensor signal extraction terminal 25 Voltage sensor signal extraction terminal 3 Current terminal 31 Electrode 32 Current sensor 33 Current sensor signal extraction terminal 51, 52 Lead frame 71, 72 Ceramic substrate 81, 82 Metal heat sink 91, 92 Heat sink

Claims (6)

A power semiconductor module comprising a plurality of power semiconductor elements for switching current, a protective circuit element for protecting the power semiconductor elements, a lead frame, and a heat dissipation mechanism ,
One power semiconductor element, one protection circuit element, and a sensor as a unit, with the first and second lead frames sandwiched therebetween, the power semiconductor element and the protection circuit element are located at positions facing each other. And fixed to the second lead frame ,
Wherein the one surface of the first lead frame, the first electrode is directly electrically connected Rutotomoni of the power semiconductor element, the first electrode facing surface a second electrode of said power semiconductor element, an L Electrically connected to the one surface of the second lead frame by a letter-shaped current terminal ;
On the other surface of the first lead frame, the first electrode is directly electrically connected Rutotomoni of the protective circuit element, to the other surface of the second lead frame, a second electrode of the protective circuit element Is electrically connected directly ,
The sensor is one or more of a temperature sensor, a current sensor, and a voltage sensor that measure the power semiconductor element , and is installed in each unit .
The current terminal is in contact with the ceramic substrate, a power semiconductor module power semiconductor device which is characterized that you are thermally connected to the heat dissipating mechanism through the current terminals. A power semiconductor module comprising a plurality of power semiconductor elements for switching current, a protective circuit element for protecting the power semiconductor elements, a lead frame, and a heat dissipation mechanism ,
One power semiconductor element, one protection circuit element, and a sensor as a unit, with the first and second lead frames sandwiched therebetween, the power semiconductor element and the protection circuit element are located at positions facing each other. And fixed to the second lead frame ,
Wherein the one surface of the first lead frame, the first electrode is directly electrically connected Rutotomoni of the power semiconductor element, the first electrode facing surface a second electrode of said power semiconductor element, an L Electrically connected to the one surface of the second lead frame by a letter-shaped current terminal ;
On the other surface of the first lead frame, the first electrode is directly electrically connected Rutotomoni of the protective circuit element, to the other surface of the second lead frame, a second electrode of the protective circuit element Is electrically connected directly ,
The sensor is one or more of a temperature sensor, a current sensor, and a voltage sensor that measure the power semiconductor element , and is installed in each unit .
The power semiconductor module , wherein the protection circuit element is in contact with a ceramic substrate and is thermally connected to a heat dissipation mechanism . Said current sensor is provided in the current terminal is electrically connected to the electrode of the power semiconductor element, said current terminal according to claim 1 or 2, characterized in that it is connected to the second lead frame Power semiconductor module. The temperature sensor, the power semiconductor module according to any one of claims 1 to 3, characterized in that it is disposed in the gap caused by said current terminal and the power semiconductor element and the protective circuit element. The temperature sensor or voltage sensor, a power semiconductor module according to any one of claims 1 to 4, characterized in that said a protective circuit element and the unitary component. The protective circuit element power semiconductor module according to any one of claims 1 to 5, characterized in that it comprises the a resistor and snubber capacitor.

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