JP2005079386A - Power semiconductor application apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a small but highly reliable power semiconductor application apparatus by decreasing the total heat resistance in the heat path from a power semiconductor chip to an air-cooled heatsink for a reduction in size of the air-cooled heatsink and by constructing a structure not requiring extra bolt torquing or grease replacement. <P>SOLUTION: In this power semiconductor application apparatus having a built-in IGBT chip 1 which is a power semiconductor element and a built-in heatsink for radiating the heat produced by the IGBT chip 1, the IGBT chip 1 is bonded to the front surface of a metal plate 3 and an air-cooled fin 4 is bonded to the rear surface of the metal plate 3. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a power semiconductor application device such as an inverter device that converts power using a power semiconductor, and more particularly to a power semiconductor application device that is required to be small and highly reliable.

  In recent years, in order to effectively use energy resources and protect the global environment, the importance of power semiconductor application devices such as inverter power converters has increased, and the need for miniaturization and higher reliability of power semiconductor application devices has also increased. Yes.

  In order to reduce the size and increase the reliability of the power semiconductor application device, it is essential to efficiently and stably cool the power semiconductor element of the main converter.

  Power semiconductor elements generate heat due to losses during switching and conduction. Since this heat generation significantly increases the temperature of the power semiconductor element, if the heat is not properly radiated, the life of the element may be reduced or even destroyed. Therefore, it is necessary to provide a cooling mechanism to the element to suppress the temperature rise. In general, this cooling mechanism occupies a large volume in the apparatus. Therefore, efficient cooling of the power semiconductor element is indispensable for downsizing the apparatus.

  In addition, many power semiconductor application devices are used in continuous operation. Even in such a case, it is desirable that the cooling mechanism and the cooling member in the cooling mechanism are free from functional deterioration and characteristic deterioration.

  However, in practice, it is difficult to completely avoid functional deterioration and characteristic deterioration. Therefore, stable cooling of the power semiconductor element for a long time is indispensable for improving the reliability of the apparatus.

For such a purpose, for example, in an inverter device, a method has been proposed in which a clearance is provided between the cooling fin and the power module mounting surface of the cooling fin so as to soak and fill a fluid resin having thermal conductivity. (See Patent Document 1)
A configuration example of a conventional power semiconductor application apparatus will be described with reference to FIGS. FIG. 8 is a configuration diagram around the elements of the power semiconductor application device, and FIG. 9 is an exploded view of FIG.

In FIG. 8, the IGBT chip 1 and the diode chip 2 which are power semiconductor elements are mounted on a module base 7 via an insulating substrate 6. The module base 7 is mounted on the air-cooled heat sink 5. A module case 8 is mounted on the module base 7. Usually, the insulating substrate 6 is formed of a good heat conductor such as ceramic, the IGBT chip 1 and the diode chip 2 are soldered to the insulating substrate 6, and the insulating substrate 6 is also soldered to the module base 7. The thermal resistance from the chip 2 to the module base 7 is made as small as possible. In the configuration example of FIG. 8, six insulating substrates 6 are soldered to one module base 7 so that a three-phase inverter circuit can be configured. There are cases where one insulating substrate is bonded to one module base and two insulating substrates are bonded to one module base.

A mechanism for mounting the module base 7 on the air-cooled heat sink 5 will be described with reference to FIG. The periphery of the module base 7 is fixed to the air-cooled heat sink 5 using a plurality of bolts 10. A thin layer of thermally conductive grease 9 is formed at the contact interface between the module base 7 and the air-cooled heat sink 5 to reduce the contact thermal resistance.
JP 2002-325467 A

  The above-described inverter device has the following two problems.

  First, it is difficult to equalize the contact surface pressure between the module base 7 and the air-cooled heat sink 5. Although fixed by a plurality of bolts 10, the surface pressure is relatively large around the bolt, and the surface pressure decreases as the distance from the bolt increases. In addition, if the flatness of the contact surfaces of both the module base 7 and the air-cooled heat sink 5 is extremely reduced, the manufacturing cost of the apparatus increases because the processing cost increases. For this reason, the distance between the contact surfaces of the module base 7 and the air-cooled heat sink 5 cannot be made completely uniform within the surface.

  For this reason, it is difficult to reduce the thickness of the layer of the heat conductive grease 9 over the entire contact surface. Therefore, it becomes difficult to keep the value of contact thermal resistance small. In order to keep the temperature of the IGBT chip 1 and the diode chip 2 below an allowable value, it is necessary to manage the total thermal resistance of the heat path from the chip to the refrigerant air. When the contact thermal resistance increases, the thermal resistance of the air-cooled heat sink 5 must be reduced to avoid an increase in the total thermal resistance. As a result, the air-cooled heat sink 5 must have a superior cooling characteristic, and the overall size is increased.

Secondly, it is difficult to avoid a decrease in the tightening force of the bolt 10 and deterioration of the characteristics of the heat conductive grease 9 due to long-term continuous use. When the apparatus is continuously used for a long time, the tightening force of the bolt 10 gradually decreases. The bolt 10 and the module base 7 which is a non-clamping part are made of different materials, and the amount of thermal expansion due to temperature change is different, which causes a reduction in clamping force. Further, when the thermal conductive grease is continuously used for a long period of time, characteristics such as thermal conductivity may be deteriorated.

  For this reason, it is difficult to stably maintain the initial state of the contact thermal resistance between the module base 7 and the air-cooled heat sink 5 for a long time. Therefore, it is necessary to design in consideration of the characteristic change, and it is necessary to reduce the thermal resistance of the air-cooled heat sink 5 by that amount to avoid an increase in the total thermal resistance. As a result, the size of the air-cooled heat sink 5 is increased as in the case of the first problem. Further, when the tightening force of the bolt 10 is lowered or the characteristic deterioration of the heat conduction grease 9 is remarkable, it is necessary to replace the heat conduction grease or to retighten the bolt 10. That is, undesired maintenance work is required.

  The object of the present invention is to reduce the total thermal resistance of the heat path from the power semiconductor chip to the air-cooled heat sink, to reduce the size of the air-cooled heat sink, and to eliminate the need for bolt tightening and grease replacement. It is to provide a power semiconductor application device with high reliability.

  In order to achieve the above object, the present invention comprises a metal plate, a power semiconductor element bonded to the surface of the metal plate, and an air cooling fin bonded to the back surface of the metal plate. Power semiconductor application device.

  According to the present invention, the heat conduction grease between the module base and the air-cooled heat sink becomes unnecessary, and the contact heat resistance is eliminated. Moreover, the bolt which fixes a module base to an air cooling heat sink becomes unnecessary. As a result, the total thermal resistance can be reduced by the contact resistance.

  As described above, according to the present invention, the total thermal resistance of the heat path from the power semiconductor chip to the air-cooled heat sink is reduced, the size of the air-cooled heat sink is reduced, and bolt tightening and grease replacement are not required. A small-sized and highly reliable power semiconductor application device can be provided.

  Embodiments of the present invention will be described below with reference to the drawings.

(First embodiment: corresponding to claim 1)
A first embodiment of the present invention will be described with reference to FIGS.

FIG. 1 is a configuration diagram around an element of the power semiconductor element application apparatus according to the first embodiment of the present invention, and corresponds to FIG. 8 of the conventional power semiconductor element application apparatus. FIG. 2 is an exploded configuration diagram of FIG. 1 and corresponds to FIG. 9 of a conventional power semiconductor device application apparatus.

  1 and 2, the IGBT chip 1 and the diode chip 2 are bonded to the surface of the metal plate 3. Moreover, the air-cooling fin 4 is joined to the back surface of the metal plate 3 by the following first to third joining methods, for example.

  In the first bonding method, the air-cooling fins 4 are collectively solder-bonded together with the IGBT chip 1 and the diode chip 2. If an element capable of operating at high temperature such as SiC is used as the power semiconductor element, brazing junction having a temperature higher than that of solder can be used.

  In the second joining method, first, the IGBT chip 1 and the diode chip 2 are joined to the metal plate 3 with a high melting point solder, and then the air-cooling fin 4 is joined with a low melting point solder.

  In the third joining method, first, the IGBT chip 1 and the diode chip 2 are soldered to the metal plate 3, and then the air-cooling fin 4 is joined by means such as ultrasonic welding or friction welding.

  In addition, since the IGBT chip 1 and the diode chip 2, the metal plate 3, and the air-cooling fin 4 are joined with metal, they cannot be insulated. Therefore, when it accommodates in an apparatus, it is necessary to insulate the metal plate 3 and the air-cooling fin 4 from a housing and another main circuit part. Further, when configuring a three-phase inverter circuit, it is necessary to prepare six metal plates 3 and six air cooling fins 4 each.

  The module case 8 shown in FIG. 8 is used in the same manner although not shown.

  When the power semiconductor device application apparatus is configured as described above, the heat conduction grease between the module base and the air-cooled heat sink is not required, and the contact thermal resistance is eliminated. Moreover, the bolt which fixes a module base to an air cooling heat sink becomes unnecessary. As a result, the total thermal resistance can be reduced by the contact resistance.

  When the total thermal resistance is made equal, the thermal resistance of the metal plate and the air-cooled fin portion can be increased by the contact thermal resistance, and the physique of the metal plate and the air-cooled fin portion can be reduced. Further, since the bolt for fixing the module base to the air-cooled heat sink is unnecessary, it is not necessary to retighten the bolt or replace the grease.

(Second embodiment: corresponding to claim 6)
Next, a second embodiment of the present invention will be described with reference to FIG.

  FIG. 3 is an exploded configuration diagram around the elements of the power semiconductor element application apparatus of the second embodiment. A metal substrate having an insulating layer 3B on the surface of the metal base 3A and a conductor pattern 3C on the surface of the insulating layer 3B is formed. The IGBT chip 1 and the diode chip 2 are bonded to the surface of the conductor pattern 3C. Moreover, the air-cooling fin 4 is joined to the back surface of the metal plate 3A. As the bonding method, the air-cooling fins 4 are collectively soldered together with the IGBT chip 1 and the diode chip 2, and a plurality of methods shown in the first embodiment can be used as appropriate.

  When the power semiconductor device application apparatus is configured as described above, the IGBT chip 1, the diode chip 2, the conductor pattern 3C, the metal base 3A, and the air cooling fin 4 can be insulated. Therefore, in addition to the effects described in the first embodiment, it is not necessary to insulate the metal base and the air cooling fin from the casing and other main circuit parts. Space can be saved, and the size can be reduced accordingly.

  Further, when configuring a three-phase inverter circuit, it is only necessary to form six conductor patterns on the insulating layer, so that the metal base and the air cooling fin can be made common, and the metal base when divided and used Since insulation between each other becomes unnecessary, the whole can be made smaller.

(Third embodiment: corresponding to claim 2)
Next, a third embodiment of the present invention will be described with reference to FIG.

  FIG. 4 is an exploded configuration diagram around the elements of the power semiconductor element application apparatus of the third embodiment. The IGBT chip 1 and the diode chip 2 are bonded to the surface of the metal plate 3. A groove 3D is formed on the back surface of the metal plate 3 at a position corresponding to the end 4A of the air cooling fin 4, and the end 4A of the air cooling fin 4 is press-fitted into the groove 3D provided on the metal plate 3.

  The metal plate 3 may be a metal base having the insulating layer and the conductor pattern shown in the second embodiment. As a bonding method, a plurality of methods shown in the first embodiment can be used as appropriate.

  When the power semiconductor device application apparatus is configured in this way, the joint portion is only between the IGBT chip 1 and the diode chip 2 and the metal plate 3, and the metal plate 3 and the fin 4 can be integrated in a non-joint structure, Since a joining member is not required, in addition to the effects described in the first and second embodiments, the reliability can be further increased.

(Fourth embodiment: corresponding to claim 3)
Next, a fourth embodiment of the present invention will be described with reference to FIG.

FIG. 5 is an exploded configuration diagram around the elements of the power semiconductor element application apparatus of the fourth embodiment. An IGBT module 1A containing an IGBT chip and a diode chip is bonded to the surface of the metal plate 3 with an electrically insulating heat conductive adhesive. Further, the joining surface 4B of the air-cooling fin 4 is adhered to the back surface of the metal plate 3 with the same adhesive, or is joined by an appropriate method shown in the first embodiment.

  When the power semiconductor device application apparatus is configured as described above, the IGBT module 1A and the metal plate 3 can be insulated from each other. Therefore, as in the second embodiment, the metal base and the air cooling fin are connected to the casing. In addition, since it is not necessary to insulate from other main circuit parts, the space required for insulating the metal base and the air-cooled fin can be saved, and the size can be reduced accordingly.

  Further, when configuring a three-phase inverter circuit, it is only necessary to form six conductor patterns on the insulating layer, so that the metal base and the air cooling fin can be made common, and the metal base when divided and used Since insulation between each other becomes unnecessary, the whole can be made smaller. Furthermore, since the IGBT module is housed in a resin package and insulated, a plurality of IGBT modules can be arranged close to each other. As a result, the entire configuration can be further reduced.

(Fifth embodiment: corresponding to claim 4)
Next, a fifth embodiment of the present invention will be described with reference to FIG.

  FIG. 6 is an exploded configuration diagram around the elements of the power semiconductor element application apparatus of the fifth embodiment. The IGBT chip 1 and the diode chip 2 are joined to the conductor pattern 3C formed on the insulating layer 3B on the surface of the metal base 3A. Further, the water-cooled heat sink 5A is joined to the back surface of the metal base 3A. As a bonding method, a plurality of methods shown in the first embodiment can be used as appropriate.

  When the power semiconductor element application device is configured in this way, the water-cooled heat sink 5A can exhibit a cooling capacity equivalent to that of the air-cooling fin with an extremely small volume, and thus the size of the element around the power semiconductor element application device can be reduced.

(Sixth embodiment: corresponding to claim 5)
Next, a sixth embodiment of the present invention will be described with reference to FIG.

FIG. 7 is an exploded configuration diagram around the elements of the power semiconductor element application apparatus of the sixth embodiment. The IGBT chip 1 and the diode chip 2 are joined to the conductor pattern 3C formed on the insulating layer 3B on the surface of the metal base 3A. Further, a heat transport body such as a heat pipe 5B is joined to the back surface of the metal base 3A. In this case, as a bonding method, a plurality of methods shown in the first embodiment can be used as appropriate.

  Further, a heat radiating fin (not shown) is provided on the opposite side of the joint portion of the heat transport body.

  When the power semiconductor element application device is configured in this way, the heat transport body such as the heat pipe 5A can carry out heat transport with an extremely small volume, so that the size of the power semiconductor element application device can be reduced.

  Note that the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the invention at the stage of implementation. In addition, the embodiments may be appropriately combined as much as possible, and in that case, combined effects can be obtained. Furthermore, the above embodiments include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements. For example, when an invention is extracted by omitting some constituent elements from all the constituent elements shown in the embodiment, when the extracted invention is implemented, the omitted part is appropriately supplemented by a well-known common technique. It is what is said.

The block diagram around the element of the power semiconductor element application apparatus of the 1st Embodiment of this invention. The disassembled block diagram around the element of the power semiconductor element application apparatus of the 1st Embodiment of this invention. The disassembled block diagram around the element of the power semiconductor element application apparatus of the 2nd Embodiment of this invention. The disassembled block diagram around the element of the power semiconductor element application apparatus of the 3rd Embodiment of this invention. The disassembled block diagram around the element of the power semiconductor element application apparatus of the 4th Embodiment of this invention. The disassembled block diagram around the element of the power semiconductor element application apparatus of the 5th Embodiment of this invention. The disassembled block diagram around the element of the power semiconductor element application apparatus of the 6th Embodiment of this invention. The block diagram around the element of the conventional power semiconductor element application apparatus. The decomposition | disassembly block diagram around the element of the conventional power semiconductor element application apparatus.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... IGBT chip, 1A ... IGBT module, 2 ... Diode chip, 3 ... Metal plate, 3A ... Metal base, 3B ... Insulating layer, 3C ... Conductor pattern, 3D ... Groove, 4 ... Air cooling fin, 4A ... End part, 4B DESCRIPTION OF SYMBOLS Joining surface, 5 ... Air-cooled heat sink, 5A ... Water-cooled heat sink, 5B ... Heat pipe, 6 ... Insulating substrate, 7 ... Module base, 8 ... Module case, 9 ... Thermal conductive grease, 10 ... Bolt.

Claims (6)

A power semiconductor application device comprising: a metal plate; a power semiconductor element bonded to the surface of the metal plate; and an air cooling fin bonded to the back surface of the metal plate. 2. The power semiconductor application device according to claim 1, wherein the metal plate is formed with a groove on the back surface, and an end of the air-cooling fin is press-fitted into the groove. The power semiconductor element is bonded to the surface of the metal plate with an electrically insulating heat conductive adhesive, and the air cooling fin is bonded or bonded to the back surface of the metal plate. The power semiconductor application apparatus according to 1. 2. The power semiconductor application device according to claim 1, wherein a water-cooled heat sink is joined to the back surface of the metal plate instead of the air-cooling fin. 2. The power semiconductor application device according to claim 1, wherein a heat transport body is joined to the back surface of the metal plate instead of the air cooling fin. 2. The metal plate according to claim 1, wherein an insulating layer is formed on a surface of a metal base, a conductor pattern is formed on the insulating layer, and the power semiconductor element is bonded on the conductor pattern. The power semiconductor application apparatus as described in any one of thru | or 5.

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