JP6696380B2 - Semiconductor device - Google Patents

Description

  The present specification discloses a semiconductor device in which a plurality of semiconductor modules are arranged inside a resin-made tubular cooler body, and a liquid refrigerant passes through an internal space of the cooler body.

  The above-mentioned semiconductor device is disclosed in Patent Documents 1 and 2. In any of the semiconductor devices, the semiconductor module includes a resin package encapsulating a semiconductor element and a pair of heat dissipation plates exposed on both surfaces of the resin package. In the cooler body, the plurality of semiconductor modules are arranged in the axial direction of the cylinder of the cooler body with the heat radiation plates of the adjacent semiconductor modules facing each other and a gap provided therebetween. The space between the adjacent semiconductor modules serves as a coolant channel (main channel). In each semiconductor module, two portions of the surface of the resin package facing the inner peripheral surface of the cooler body are joined to the inner peripheral surface. Refrigerant passages (connection passages) through which the refrigerant flows are formed on both sides of the joint between the resin package and the cooler body in the axial direction of the cylinder of the cooler body. Two connection channels are formed on one side of one semiconductor module. A coolant supply port and a coolant discharge port are provided at one end in the axial direction of the cylinder of the cooler body, and the liquid coolant introduced from the coolant inlet port is distributed to all the main flow channels through one connection flow channel. . The liquid refrigerant that has contacted the heat dissipation plate in the main flow path and has absorbed the heat of the semiconductor element is discharged from the refrigerant discharge port through the other connection flow path. Such a semiconductor device has high cooling efficiency for a plurality of semiconductor modules (semiconductor elements) and is used, for example, in an inverter that drives a running motor of an electric vehicle.

JP 2012-033864 A JP 2012-009569 A

  In the semiconductor device of Patent Document 1, both the resin package that seals the semiconductor element and the liquid coolant flow path are made of resin. It is desirable that such a resin has a large specific heat so as to absorb the heat of the semiconductor element well. On the other hand, it is also desirable that the substance is not easily hydrolyzed so that it does not easily deteriorate even when it comes into contact with a liquid refrigerant. Resins that combine both properties are most desirable, but such resins are expensive. The technology disclosed in the present specification provides a semiconductor device, which is made of resin, is less likely to deteriorate, and has high cooling performance for semiconductor elements, at low cost.

A semiconductor device disclosed in the present specification is a cooler-integrated device in which a plurality of semiconductor modules are arranged inside a resin-made tubular cooler body, and a liquid refrigerant passes through an internal space of the cooler body. is there. Each semiconductor module includes a resin package encapsulating a semiconductor element and a pair of heat radiation plates exposed on both sides (a pair of parallel side surfaces) of the resin package. In the cooler main body, the plurality of semiconductor modules are arranged in the axial direction of the cylinder of the cooler main body, with the heat radiation plates of the adjacent semiconductor modules facing each other and a gap provided therebetween. Each semiconductor module is joined to two locations on the inner peripheral surface of the cylinder of the cooler body. The cooler body and the outer peripheral portion exposed in the flow path of the resin package (internal space of the cooler body) are made of the first resin. The semiconductor element is sealed between the pair of heat sinks, and the inner portion of the outer peripheral portion that is not exposed to the internal space is made of the second resin. The first resin is made of a resin material that is less likely to be hydrolyzed than the second resin, and the second resin is made of a resin material having a larger specific heat than the first resin. That is, a resin that is difficult to hydrolyze (first resin) is used for the portion that comes into contact with the liquid refrigerant, and a resin (second resin) that has a high specific heat is used for the portion that does not touch the liquid refrigerant but surrounds the periphery of the semiconductor element. A substance having a large specific heat can absorb a larger amount of heat than a substance having a small specific heat in the same volume. By using a resin having appropriate characteristics depending on the location, it is possible to inexpensively realize a semiconductor device that can achieve both deterioration resistance to a liquid refrigerant and cooling performance to a semiconductor element. Details of the technology disclosed in the present specification and further improvements will be described in the following “Description of Embodiments”.

It is a perspective view of a semiconductor device of an example. It is a perspective view of a resin frame which constitutes a cooler body, and a semiconductor module joined to the resin frame. FIG. 3 is a sectional view taken along line III-III in FIG. 2. FIG. 4 is a sectional view taken along line IV-IV in FIG. 2.

  A semiconductor device 2 according to an embodiment will be described with reference to the drawings. FIG. 1 shows a perspective view of the semiconductor device 2. The semiconductor device 2 is a device in which a cooler and a semiconductor module (transistor chip) to be cooled are integrated. The semiconductor device 2 has a plurality of built-in transistor chips and is used, for example, as a main part of an inverter that converts DC power into three-phase AC power.

  The semiconductor device 2 includes a tubular cooler body 10, in which a plurality of semiconductor modules having transistor chips sealed therein are housed. The cooler main body 10 is formed by connecting a plurality of resin frame bodies 10a to 10g, and has a tubular shape as a whole. The ends of the tubular cooler body 10 in the axial direction (X direction in the drawing) are closed by a front end cover 5 and a rear end cover 6. The front end cover 5 is provided with a coolant supply port 7 and a coolant discharge port 8. The entire internal space of the cooler body 10 serves as a refrigerant flow path. The coolant supply port 7 and the coolant discharge port 8 are connected to a coolant circulation device (not shown), the liquid coolant is supplied from the coolant supply port 7, absorbs heat from the semiconductor module inside the cooler body 10, and It is discharged from the discharge port 8. The transistor chip is a cooling target of the cooler body 10. The refrigerant is water or a liquid such as LLC (Long Life Coolant).

  As will be described later in detail, the semiconductor module is bonded to the inside of each of the plurality of resin frames 10a-10g. Two transistor chips are built in one semiconductor module. Three power terminals 3a, 3b, 3c extend from the outer surface of each resin frame 10a-10g, and a plurality of control terminals 4 extend. The two transistor chips are connected in series inside the semiconductor module, and the power terminal 3a is electrically connected to the high potential side of the series connection. The power terminal 3b is electrically connected to the low potential side of the series connection. The power terminal 3c is electrically connected to the midpoint of the series connection. The plurality of control terminals 4 are a gate terminal connected to the gate of the transistor chip, a sensor terminal connected to a sense emitter for measuring a current flowing through the transistor chip, and the like.

  FIG. 2 shows a perspective view of one resin frame body 10a. The other resin frames 10b-10g also have the same structure. The semiconductor module 13 is joined to the inner peripheral surface 12a of the resin frame body 10a. The semiconductor module 13 is joined to the inner peripheral surface 12a at two points in the Z direction in the coordinate system of FIG. As a result, through holes 12c and 12d are formed at two positions in the Y direction of the coordinate system in the figure. A double gasket 21 is arranged on the end face 12b of the cylinder of the resin frame body 10a in the axial direction (X direction in the drawing). A double gasket 21 is similarly arranged on the end face opposite to the end face 12b. As described above, the plurality of resin frame bodies 10a-10g are stacked in the axial direction (X direction in the drawing) of the cylinder. At that time, the adjacent resin frames contact each other with the double gasket 21 sandwiched therebetween, and the internal space of the cylinder (internal space of the cooler body 10) is sealed. As described with reference to FIG. 1, both ends in the axial direction of the cylinder of the cooler body 10 are sealed by the front end cover 5 and the rear end cover 6. Hereinafter, for convenience of explanation, the axial direction of the cylinder (X direction in the drawing) may be referred to as the cylinder axial direction.

  When the plurality of resin frame bodies 10a-10g, the front end cover 5, and the rear end cover 6 are assembled, the through holes 12c of the plurality of resin frame bodies 10a-10g and the refrigerant supply port 7 are aligned in the cylinder axis direction and penetrate the same. The hole 12d and the refrigerant outlet 8 are aligned. Further, as shown in FIG. 2, a space is secured between the end surface of the resin frame body 10a and the semiconductor module 13 in the cylinder axis direction of the resin frame body 10a (X direction in the drawing). The space where the semiconductor module 13 faces in the cylinder axis direction becomes the main flow path Pa through which the liquid refrigerant flows. The main flow paths Pa are formed on both sides of the semiconductor module 13 in the cylinder axis direction. The through holes 12c and 12d serve as connection flow paths that connect the main flow paths Pa of the adjacent resin frame bodies 10a-10g. The main flow path Pa and the connection flow path are internal spaces of the cooler body 10.

  The liquid refrigerant supplied from the refrigerant supply port 7 is distributed to the main flow paths Pa of the resin frames 10a-10g through the through holes 12c (connection flow paths) aligned in a straight line. The liquid coolant distributed in the main flow paths Pa of the resin frames 10a-10g flows along the surface of the semiconductor module 13 (the surface of the surface facing the cylinder axis direction). The liquid coolant absorbs heat from the semiconductor module 13 while flowing along the surface of the semiconductor module 13. The liquid refrigerant that has absorbed heat in each of the resin frames 10a-10g is discharged from the cooler body 10 through the other through hole 12d (connection flow path) and the refrigerant discharge port 8. On the surface of the semiconductor module 13, a heat radiating plate 19a that transfers the heat of the internal transistor chip is exposed, and a plurality of fins 14 are provided on the surface. The heat dissipation plate 19a and the fins 14 promote cooling of the semiconductor module 13. Although not visible in FIG. 2, the heat dissipation plate 19b is exposed on the side opposite to the heat dissipation plate 19a, and the heat dissipation plate 19b is also provided with a plurality of fins 14.

  The internal structure of the semiconductor module 13 will be described. 3 is a sectional view taken along line III-III in FIG. 2, and FIG. 4 is a sectional view taken along line IV-IV in FIG. The semiconductor module 13 includes a resin package 15 that seals the two transistor chips 17a and 17b, and heat dissipation plates 19a and 19b exposed on both surfaces of the resin package 15. As shown in FIG. 3, the resin package 15 sandwiches the edges of the heat dissipation plates 19a and 19b from both sides, and is firmly fixed to the heat dissipation plates 19a and 19b. As described above, the fins 14 are provided on the surfaces of the heat dissipation plates 19a and 19b. The heat dissipation plates 19a and 19b and the fins 14 are made of copper or aluminum having high thermal conductivity.

  Each of the transistor chips 17a and 17b is a flat plate type, and the collector electrode and the gate electrode are exposed on one wide surface and the emitter electrode is exposed on the other wide surface. The conductive plate 16c is arranged on the heat dissipation plate 19b, and the two transistor chips 17a and 17b are bonded thereon. An insulating sheet (not shown) is sandwiched between the heat dissipation plate 19b and the conductive plate 16c. The emitter electrode of the transistor chip 17a and the collector electrode of the transistor chip 17b are connected to the conductive plate 16c.

  The spacer 18 is bonded to the upper surface of the transistor chip 17a, and the conductive plate 16a is bonded to the upper surface thereof. The spacer 18 is made of copper that conducts electricity and heat well. The collector electrode of the transistor chip 17a is electrically connected to the conductive plate 16a via the spacer 18. The spacer 18 is bonded to the upper surface of the transistor chip 17b, and the conductive plate 16b is bonded to the upper surface thereof. The emitter electrode of the transistor chip 17b is electrically connected to the conductive plate 16b via the spacer 18. The conductive plates 16a and 16b are located on the back side of the heat dissipation plate 19a. Although not shown, an insulating sheet is also sandwiched between the heat dissipation plate 19a and the conductive plates 16a and 16b.

  Due to the connection structure of the conductive plates 16a, 16b, 16c and the transistor chips 17a, 17b, the transistor chips 17a, 17b are connected in series via the conductive plate 16c, and the transistor chips 17a on the high potential side of the series connection are connected. The collector electrode is connected to the conductive plate 16a, and the emitter electrode of the transistor chip 17b on the low potential side is connected to the conductive plate 16c. The conductive plate 16a is connected to the power terminal 3a described above inside the resin package 15 (see FIG. 4). The conductive plates 16b and 16c are connected to the power terminals 3b and 3c described above inside the resin package 15, respectively. Further, as shown in FIG. 4, the gate electrode (and the sense emitter terminal and the temperature sensor terminal) of the transistor chip 17a is connected to the control terminal 4 inside the resin package 15 via the bonding wire 22. The same applies to the gate electrode and the like of the transistor chip 17b.

  The semiconductor module 13 is arranged inside the other resin frames 10b-10g as in FIGS. 3 and 4. Therefore, in the plurality of semiconductor modules 13, the radiator plates 19a (19b) of the adjacent semiconductor modules face each other in the cooler body 10 (resin frame bodies 10a to 10g), and a gap is provided between them to cool the cooler. The main bodies 10 (resin frames 10a-10g) are arranged in the cylinder axis direction (X direction in the drawing). The space between the adjacent semiconductor modules 13 becomes the main flow path Pa.

  The resin material of the cooler body 10 (resin frames 10a-10g) and the resin material of the resin package 15 of the semiconductor module 13 will be described. The semiconductor module 13 is made of two kinds of resins. The outer peripheral portion 15a exposed in the coolant flow path of the resin package (the through holes 12c and 12d and the main flow path Pa, which means the internal space of the cooler body 10) is made of the first resin. While the transistor chips 17a and 17b are sealed between the pair of heat sinks 19a and 19b, the inner portion 15b which is not exposed to the refrigerant flow passage (internal space of the cooler body 10) inside the outer peripheral portion 15a is Made of second resin. The cooler body 10 (resin frames 10a-10g) is made of the first resin.

  The first resin has a property of being less likely to be hydrolyzed than the second resin, and the second resin has a property of having a larger specific heat than the first resin. For example, the first resin is epoxy, PPS resin (polyphenylene sulfide resin), PA resin (polyamide resin), or the like. The second resin is, for example, an epoxy resin containing paraffins having a high latent heat property. The semiconductor device 2 has the following advantages by using the two types of resins described above.

  The liquid refrigerant flows in the internal space (through holes 12c, 12d, main flow path Pa) of the cooler body 10. The cooler body 10 is made of resin, and its deterioration progresses faster than metal. The deterioration of the resin means that the resin is hydrolyzed by being exposed to water. On the other hand, as shown in FIGS. 3 and 4, resin is also filled around the transistor chips 17a and 17b, which are heating elements. From the perspective of cooling the transistor chips 17a and 17b, it is preferable to dispose a substance having a high thermal conductivity or a substance having a high specific heat around the transistor chips 17a and 17b. If there is a resin having a high deterioration resistance to the liquid refrigerant and a large specific heat, it is desirable to use such a resin for the cooler body 10 (resin frame 10a-10g) and the resin package 15. However, such resins do not exist or, if they do exist, they are expensive. Therefore, in the semiconductor device 2 of the example, a resin material having a property of high deterioration resistance (a property of being hard to be hydrolyzed) is adopted in a portion that comes into contact with the liquid refrigerant, with emphasis on deterioration resistance rather than specific heat. On the other hand, in a portion (inner portion 15b) around the transistor chips 17a and 17b that does not come into contact with the liquid refrigerant, the heat absorption performance is emphasized rather than the deterioration resistance, and a resin material having a large specific heat is adopted. In other words, a resin material that is less likely to be hydrolyzed than the second resin is used for the first resin, and a resin material having a larger specific heat than the first resin is used for the second resin. By using the two types of resin materials in this manner, both deterioration resistance and cooling performance for the transistor chips 17a and 17b are achieved.

  Points to be noted regarding the technique described in the embodiment will be described. The transistor chips 17a and 17b of the embodiment correspond to an example of the claimed semiconductor device. The semiconductor device disclosed in this specification may house a semiconductor element other than a transistor chip in a semiconductor module.

  Specific examples of the present invention have been described above in detail, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above. The technical elements described in the present specification or the drawings exert technical utility alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technique illustrated in the present specification or the drawings can achieve a plurality of purposes at the same time, and achieving one of the purposes has technical utility.

2: Semiconductor devices 3a, 3b, 3c: Power terminal 4: Control terminal 5: Front end cover 6: Rear end cover 7: Refrigerant supply port 8: Refrigerant discharge port 10: Cooler body 10a-10g: Resin frame 12a: Inside Peripheral surface 12b: End surfaces 12c, 12d: Through hole 13: Semiconductor module 14: Fin 15: Resin package 15a: Outer peripheral portion 15b: Inner portions 16a, 16b, 16c: Conductive plates 17a, 17b: Transistor chip 18: Spacers 19a, 19b : Heat sink 21: Gasket 22: Bonding wire Pa: Main flow path

Claims (1)

A plurality of semiconductor modules are arranged inside a resin-made tubular cooler body, which is a semiconductor device in which a liquid refrigerant passes through the internal space of the cooler body.
Each of the semiconductor modules includes a resin package encapsulating a semiconductor element, and a pair of heat sinks exposed on each of a pair of parallel side surfaces of the resin package,
The plurality of semiconductor modules are arranged in the axial direction of the cylinder of the cooler body, with the radiator plates of the adjacent semiconductor modules facing each other in the cooler body, with a gap therebetween.
Each of the semiconductor modules is bonded to two places on the inner peripheral surface of the cylinder of the cooler body,
The cooler body and an outer peripheral portion exposed to the internal space of the resin package are made of a first resin, and seal the semiconductor element between the pair of heat dissipation plates, and the inner side of the outer peripheral portion. The inner part that is not exposed to the internal space is made of a second resin,
The semiconductor device according to claim 1, wherein the first resin is made of a resin material that is less likely to be hydrolyzed than the second resin, and the second resin is made of a resin material having a larger specific heat than the first resin.

Images