JP2012049167A - Power semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power semiconductor device which achieves high heat radiation suitable for a high capacity power semiconductor element and deals with prevention of deformation of radiation fins.SOLUTION: A power semiconductor device 1 includes: a power semiconductor element 2; a base plate 4 on which the power semiconductor element 2 is placed; radiation fins 7 formed on a surface of the base plate 4, which is opposite to the surface on which the power semiconductor element 2 is placed; an enclosure 8 forming ventilation flues using each radiation fin 7 as part of a wall; and a mold resin 12 sealing the power semiconductor element 2. The power semiconductor device 1 cools the power semiconductor element 2 with airflow flowing in the ventilation flues formed by the enclosure 8, and this structure realizes the small power semiconductor device 1 which effectively works for the high capacity power semiconductor element 2 and achieves excellent cooling performance.

Description

  The present invention relates to a power semiconductor device in which a power semiconductor element is mounted and heat dissipation efficiency is improved.

  Conventionally, in many power semiconductor devices, when installing a heat sink such as a heat sink in order to cool electronic components such as CPUs and power transistors, the thermal conductivity is increased by filling a fine gap at the junction between the two. Therefore, it is widely practiced to apply a heat dissipating grease. Since the thermal conductivity of grease is very low compared to metals, in order to achieve even higher heat dissipation of power semiconductor devices, the power semiconductor device and heat sink are directly fixed without using grease. It is demanded to make it.

  For example, in the heat radiation fin-integrated power module disclosed in Patent Document 1, the cooling fin and the power module metal plate are integrated without using grease, which is an obstacle to achieving high heat dissipation. By heat-bonding the cooling fin to the module metal plate with an insulating resin sheet with high thermal conductivity, or by integrally forming it, and mounting electronic components such as power semiconductor elements and wiring members on the metal plate of the power module, High heat dissipation of power semiconductor devices is achieved.

  In such a power module, a cooling fin is thermocompression bonded with an insulating resin sheet having a high thermal conductivity, or an electronic component such as a power semiconductor element or a wiring member is formed on a metal plate formed integrally. After mounting the parts, the case is attached with mold resin. However, if heat sink fins (cooling fins) are attached to the metal plate of the power semiconductor device (power module) before mounting electronic components such as power semiconductor elements and wiring members, the heat capacity of the base plate of the power semiconductor device is large. Thus, not only is soldering difficult, but a conventional jig cannot be used even in the wire bonding process, and a special jig must be made for each shape of the base plate and the radiation fin. And whenever the product to be manufactured is changed, it is also necessary to change the assembly apparatus such as a jig. In addition, since the power semiconductor device becomes larger due to the attachment of heat radiation fins, the number of power semiconductor devices that can be stored in the storage container is reduced during product production, and it must be supplied manually or by dedicated machines. Sex is reduced.

  This problem can be solved by reducing the thickness of the base plate of the power semiconductor device in advance, mounting electronic components such as power semiconductor elements and wiring members on the base plate, and finally attaching a radiation fin. be able to. However, when a thermal attachment method such as soldering or welding is used to attach the radiating fin to the base plate, the power semiconductor device has a large heat capacity, so the productivity is low, while the radiating fin is completed. When mechanically fixing the power semiconductor device to the base plate of the power semiconductor device, stress is applied to the power semiconductor device when the radiating fin is attached, and damage to the power semiconductor device becomes a problem.

  As a countermeasure, for example, in the power semiconductor circuit device and the manufacturing method thereof disclosed in Patent Document 2, a groove is provided in the heat dissipating fin joint portion of the base plate, and a part of the surface of the base plate including the portion where the groove is formed. The resin mold is exposed and the heat radiation fins are inserted into the grooves and fixed by caulking to form the heat radiation fins without damaging the power semiconductor device, simplifying the manufacturing process and improving productivity. A power semiconductor circuit device capable of achieving the above has been disclosed.

Japanese Patent Laid-Open No. 11-204700 WO2009 / 150995A1 publication

  However, in recent years, power semiconductor devices are required to have a large capacity, and the amount of heat generation tends to increase, and further miniaturization is being promoted. For this reason, the size and installation area of the radiating fins are restricted, and the increase in the amount of heat generated must be dealt with. The conventional heat radiating method is insufficient, and power semiconductor devices require further measures for heat radiating. There was a problem of being.

  In order to improve the heat dissipation performance of the power semiconductor device, it is effective to increase the heat dissipation area by reducing the fin pitch of the heat dissipation fins and increasing the number of fins. Is often set to the minimum necessary thickness. For this reason, the heat radiation performance is limited and the strength of the heat radiation fins is reduced, and when the power semiconductor device is assembled to other equipment during the manufacturing process or transportation, the heat radiation fins may come into contact with something and deform. There was also a problem that there was.

  The present invention has been made to solve the above-described problems, and provides a power semiconductor device that is suitable for high-capacity power semiconductor elements and that is suitable for preventing deformation of the radiation fins. It is aimed.

  In order to solve the above problems, a power semiconductor device according to the present invention includes a power semiconductor element, a base plate on which the power semiconductor element is placed, a mold resin that seals the power semiconductor element, and the base plate. Groove processing is performed on the surface opposite to the surface on which the power semiconductor element is placed, and the radiating fin fixed by caulking in the groove, and the enclosure surrounding the radiating fin leaving a space serving as an air passage, It is characterized by comprising.

  According to the power semiconductor device of the present invention, the power semiconductor element is cooled by an air flow with the enclosure having the heat radiating fin as a part of the wall as a ventilation path, so that it is small and efficient even for a large capacity power semiconductor element. Therefore, a power semiconductor device with excellent cooling performance can be realized.

1 is a schematic cross-sectional view showing a power semiconductor device in a first embodiment. FIG. 3 is a schematic cross-sectional view showing a component configuration of the power semiconductor device according to the first embodiment. FIG. 6 is a schematic cross-sectional view showing another configuration example of the power semiconductor device in the first embodiment.

  Hereinafter, a power semiconductor device according to an embodiment of the present invention will be described with reference to FIGS.

Embodiment 1 FIG.
FIG. 1 is a schematic cross-sectional view showing the power semiconductor device according to the first embodiment, and FIG. 2 is a schematic cross-sectional view showing a component configuration of the power semiconductor device.

As shown in FIG. 1, the power semiconductor device 1 includes a power semiconductor element 2 and the power semiconductor element 2.
A wiring member 3 for electrical connection to the outside on which the circuit board is placed, a base plate 4 on which the wiring member 3 is mounted, and the wiring member 3, the base plate 4, the wiring member 3, and the power semiconductor element 2 are joined to each other. A bonding material 5 to be connected, a wire 6 that electrically connects the power semiconductor element 2 to the wiring member 3 and the power semiconductor element 2, a heat radiation fin 7 that fits into a groove 4 a formed in the base plate 4, and heat dissipation The air passage side plate 9 and the cover plate 10 of the enclosure 8 that forms the air passage with the fins 7 and the holes 9a for fixing the air passage side plate 9 and the cover plate 10 to each other with screws 11a and nuts 11b of the fastening member 11. , 10a and a mold resin 12 for sealing the power semiconductor element 2.

As the power semiconductor element 2, for example, an IGBT (Insulated Gate BipoIar Transistor) or a MOSFET (Metal Oxide).
There is a Semiconductor Field Id Effect Transistor).

  Next, assembly of the power semiconductor element device 1 will be described with reference to cross-sectional views showing the component configuration of the power semiconductor device of FIG.

  First, the power semiconductor element 2 is placed on the wiring member 3 and bonded by the bonding material 5. Subsequently, the wiring member 3 is bonded and fixed to the base plate 4 made of metal by the bonding material 5. For example, the base plate 4 is manufactured by extrusion, casting or die casting with aluminum. As the bonding material 5, solder or an adhesive having excellent thermal conductivity is used. Electrical connection between the power semiconductor element 2 and the wiring member 3 or between the power semiconductor elements 2 is performed by bonding of the wires 6.

  The power semiconductor element 2 and the wiring member 3 on which the power semiconductor element 2 is placed and the base plate 4 are epoxy molds so that the back surface of the base plate 4 and a part of the side surface of the base plate 4 are exposed. Resin mold sealing is performed by transfer molding using the resin 12.

  On the opposite surface of the base plate 4 to which the wiring member 3 on which the power semiconductor element 2 is mounted is joined, a groove 4a is processed, and the convexity of the radiating fin 7 in which an aluminum-based plate material is processed into a wave shape. The portion is deformed and fitted into the groove 4a of the base plate 4, and the heat radiating fins 7 are joined by caulking. A ventilation path side plate 9 for forming a ventilation path so as to surround both side surfaces of the radiating fin 7 is fixed at the same time when the base plate 4 and the radiating fin 7 are caulked and joined. That is, the ventilation path side plate 9 is provided with an opening 9c corresponding to the protruding portion 4b formed by processing the groove 4a of the base plate 4, and after fitting the opening 9c and the protruding portion 4b, By caulking and joining the radiating fins 7, the bottom of the ventilation path side plate 9 is sandwiched between the base plate 4 and the radiating fins 7 and is firmly fixed without using any screws or adhesives. Further, the upper portion of the ventilation path side plate 9 is covered with a cover plate 10, and the radiating fin 7, the ventilation path side plate 9 and the cover plate 10 form an enclosure 8 that forms a ventilation path. It is possible to cool the power semiconductor element 2 efficiently by sending an air flow from the outside to the ventilation path of the enclosure 8 formed in this way by a blower (not shown). Moreover, you may connect the enclosure 8 with another cooling pipe. As the ventilation path side plate 9 and the cover plate 10, it is preferable to use a highly rigid metal plate such as stainless steel or a galvanized steel plate.

  In order to improve the heat dissipation performance of the power semiconductor device, it is effective to increase the heat dissipation area by reducing the fin pitch of the heat dissipation fins and increasing the number of fins. Is often set to the minimum necessary thickness. For this reason, the heat radiation performance is limited and the strength of the heat radiation fins is reduced, and when the power semiconductor device is assembled to other equipment during the manufacturing process or transportation, the heat radiation fins may come into contact with something and deform. However, the cover plate 10 is attached to the side of the leg portion 9b of the air passage side plate 9, so that when the power semiconductor device is assembled to other equipment during the manufacturing process or transportation, the heat radiating fin is used. Can prevent deformation due to contact with something.

  In addition, the power semiconductor device 1 may be assembled and fixed to other devices, and the legs 9b and the holes 9a provided on the ventilation path side plate 9 can be easily assembled and fixed to other devices. It is configured. Further, the cover plate 10 is provided with a similar hole 10a at a position corresponding to the hole 9a provided in the ventilation path side plate 9, so that when the power semiconductor device is assembled to another device, the cover plate 10 is covered. Since the plate 10 is also firmly fixed at the same time, it is not necessary to firmly fix the ventilation path side plate 9 and the cover plate 10, and it is sufficient that the plate 10 is held to such an extent that it does not fall off by snap fit or the like. There is an effect that the work becomes easy. In addition, by making the hole 10a larger than the hole 9a, it is possible to prevent problems such as a screw not being inserted when the power semiconductor device 1 is assembled to another device even if the positions of both are shifted. As a result, the assembly of the power conversion device is facilitated.

  Furthermore, as shown in another configuration example of the power semiconductor device in FIG. 3, the wall surface of another electronic device 13 or an electronic component may be used instead of the cover plate 10. The enclosure 8 that forms the ventilation path is configured by the combined assembly.

  Although the power semiconductor device according to the first embodiment is configured as described above, there may be a plurality of power semiconductor elements 2, and the power semiconductor elements 2 may be connected to the base plate 4 without the wiring member 3 interposed therebetween. It may be mounted by directly bonding with a bonding material 5 of solder or adhesive. Further, the power semiconductor element 2 and the wiring member 3 are bonded to the base plate 4 with an insulating material such as a ceramic substrate for the purpose of insulation from the base plate 4, and the insulating member is bonded to the base plate 4. May be bonded to the base plate 4.

  The heat dissipating fins 7 attached by caulking and joining to the grooves 4a processed on the back surface of the base plate 4 may be one plate processed into a wave shape, and the fins are independent one by one. It may be formed. In addition, the mounting of the radiating fins 7 to the base plate 4 may be performed by deforming and crimping the base plate 4 or may be performed by pressing between them.

  As the mold material, epoxy resin is preferable because it is hard and can avoid damage to the power semiconductor element 2. The periphery of the power semiconductor element 2 is made of epoxy resin by a method such as potting, transfer molding or casting. It is desirable that the structure be molded, and it is preferable that the top surface be as flat as possible so that the entire surface of the mold resin can be subjected to caulking pressure.

  As described above, the material of the air passage side plate 9 and the cover plate 10 is preferably a stainless steel plate or a galvanized steel plate having high rigidity, excellent environmental resistance, and easy bending, but is not limited thereto. Any material may be used as long as it has necessary rigidity, can be easily processed into a desired shape, and has excellent environmental resistance. That is, it may be an injection molded product of a thermoplastic resin.

  The ventilation path side plate 9 and the cover plate 10 only need to be excellent in heat dissipation and may be any insulating member, and may be an insulating member, but the cover plate 10 excellent in electrical conductivity may be made of metal. With this configuration, it is possible to connect the radiating fin 7 to the ground potential via these, and it becomes easy to suppress radiation noise and malfunction. In particular, when a SiC semiconductor that performs a high-speed switching operation is used as the power semiconductor element 2, noise is likely to occur, and thus the material of the ventilation path side plate 9 and the cover plate 10 is made of a metal material or a conductive material. Since the fin 7 can be connected to the ground potential, the generation of noise can be suppressed, which is effective.

The semiconductor material of the power semiconductor element 2 is not only a silicon semiconductor but also a wide band gap semiconductor having a larger band gap than silicon (Si) such as SiC (Silicon Carbide), gallium nitride (GaN), and diamond. It may be a power semiconductor device.

  In addition, power semiconductor elements using wide band gap semiconductors have high voltage resistance and high allowable current density, so the elements can be miniaturized, and power semiconductor devices incorporating miniaturized power semiconductor elements can be miniaturized. Is possible.

  In addition, since the heat resistance is high, the radiating fins of the heat sink can be downsized and the water cooling unit can be down cooled, so that the power semiconductor device can be further downsized.

  Furthermore, since the power loss is low, it is possible to increase the efficiency of the power semiconductor element, and further increase the efficiency of the power semiconductor device.

  As described above, according to the power semiconductor device in the first embodiment, the power semiconductor element is formed by the air flow by configuring the enclosure having the ventilation path side plate, the cover plate, and the heat radiation fin as a part of the wall surface as the ventilation path. It is possible to cool efficiently, and it is possible to realize a power semiconductor device that is small and efficient even for a large-capacity power semiconductor element and has excellent cooling performance.

  In addition, because the ventilation path side plate and the cover plate are attached, the heat radiation fins are protected, and when the power semiconductor device is assembled to other equipment during the manufacturing process or transportation, deformation due to the heat radiation fins coming into contact with something. There is also an effect that it can be prevented.

  In the drawings, the same reference numerals indicate the same or corresponding parts.

DESCRIPTION OF SYMBOLS 1 Power semiconductor device 2 Power semiconductor element 3 Wiring member 4 Base board 5 Joining material 6 Wire 7 Radiation fin 8 Enclosure 9 Ventilation path side board 10 Cover board 12 Mold resin 13 Other electronic devices

Claims (7)

A power semiconductor element;
A base plate on which the power semiconductor element is placed;
A mold resin for sealing the power semiconductor element;
Groove processing is performed on the surface of the base plate opposite to the surface on which the power semiconductor element is placed, and heat radiating fins fixed to the groove by caulking,
An electric power semiconductor device comprising: an enclosure that leaves a space that becomes a ventilation path for the heat radiating fins.   The power semiconductor device according to claim 1, wherein the enclosure is made of a metal material or a conductive material.   3. The power semiconductor device according to claim 1, wherein the enclosure includes an air passage side plate and a cover plate.   The power semiconductor device according to claim 3, wherein the cover plate uses a wall surface of another electronic device or electronic component.   When the radiating fin is caulked and fixed to the groove of the base plate, a part of the ventilation path side plate is sandwiched between the end of the radiating fin and the base plate, and the ventilation path side plate is fixed simultaneously. 5. The power semiconductor device according to claim 3 or 4, wherein:   The power semiconductor device according to claim 1, wherein the power semiconductor element is formed of a wide band gap semiconductor element. The power semiconductor device according to claim 6, wherein the wide band gap semiconductor element is made of silicon carbide, gallium nitride, or diamond.

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