JP2016111271A - Semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To inhibit deformation of a whole device due to repetition of a heating/cooling cycle.SOLUTION: A semiconductor device comprises: bus bars 22h, 22g arranged in such a manner that a volume in an upper part 26a of a power card 26 becomes larger than a volume in a lower part 26b; and a recess 26c formed on the lower side and only between a semiconductor element 22 and a semiconductor element 23. With this configuration, a difference between a volume of a resin 24 in the upper part 26a and a volume in the lower part 26b can be minimized and deformation in the whole of the power card 26 can be inhibited by inhibiting concentration of thermal stress due to repetition of a heating/cooling cycle.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a semiconductor device, and more particularly to a plate-like semiconductor device in which a plurality of semiconductor elements are arranged side by side, the plurality of semiconductor elements are connected to each other by a connecting member, and these are molded with a resin.

  Conventionally, this type of semiconductor device includes a semiconductor element, a heat sink bonded to one surface of the semiconductor element, a resin that seals the semiconductor element and the heat sink with the surface of the heat sink exposed, and exposure of the heat sink. There has been proposed one that includes a bus bar terminal that is press-contacted to a surface and an insulating plate that is brazed to the bus bar terminal (see, for example, Patent Document 1). In this apparatus, since the heat sink and the bus bar terminal are formed separately, the thickness of the bus bar terminal can be made thinner than that in which the heat sink and the bus bar terminal are integrally formed. Thereby, when the insulating plate is brazed to the bus bar terminal, thermal stress applied from the bus bar terminal to the insulating plate is relieved.

JP 2014-33125 A

  In the semiconductor device described above, thermal stress is generated in the resin due to heat generated by the operation of the semiconductor element. Depending on the shape of the resin, such thermal stress may be concentrated on a portion, and the entire device may be deformed around the portion where the thermal stress is concentrated due to repeated heating and cooling cycles of the resin due to heat generation of the semiconductor element and subsequent cooling. .

  The main object of the semiconductor device of the present invention is to provide a configuration that suppresses deformation of the entire device due to repeated heating and cooling cycles.

  The semiconductor device of the present invention employs the following means in order to achieve the main object described above.

The semiconductor device of the present invention is
A plate-like semiconductor device in which a plurality of semiconductor elements are arranged side by side, and the plurality of semiconductor elements are connected to each other by a connecting member, and these are molded with a resin,
The connecting member is arranged so that the volume on one side in the plate thickness direction is larger than the volume on the other side,
A recess is formed on the other side of the resin in the plate thickness direction and only between two adjacent semiconductor elements among the plurality of semiconductor elements.

  In the semiconductor device of the present invention, a plurality of semiconductor elements are arranged side by side, the plurality of semiconductor elements are connected to each other by a connecting member, and these are molded with resin to form a plate. The connecting member is arranged such that the volume on one side in the plate thickness direction is larger than the volume on the other side, and the two adjacent semiconductors on the other side in the plate thickness direction of the resin and among the plurality of semiconductor elements Concave portions are formed only between the elements. If the difference between the volume on the other side of the resin in the plate thickness direction and the volume on the one side is large, thermal stress is applied to a part of the resin due to repeated heating / cooling cycles due to heat generated by the operation of the semiconductor element and subsequent cooling. In some cases, the entire apparatus is deformed. In particular, if the volume of the resin is uneven, the amount of deformation on the side with less resin increases. Also, thermal stress tends to concentrate between the semiconductor elements. By forming a recess on the other side in the resin thickness direction and only between two adjacent semiconductor elements among the plurality of semiconductor elements, the volume and one side on the other side in the resin thickness direction are formed. The volume on the other side in the plate thickness direction of the resin can be made the same as the volume on the one side, suppressing the concentration of thermal stress on the resin due to repeated heating and cooling cycles can do. Thereby, the deformation | transformation of the whole apparatus can be suppressed.

  In such a semiconductor device of the present invention, the connection member is a plate-like member, and the recess has an opening whose shape is substantially the same as a cross-sectional shape parallel to the plate thickness direction of the connection member, and has a depth. May be formed to be within a range of 20% to 40% of the plate thickness of the semiconductor device, and the connection member is formed in a plate shape and the plate thickness on one side in the plate thickness direction. It is a member having an extending portion extending perpendicularly to the direction, and the concave portion is more than the thickness of the resin on the one side in the plate thickness direction of the extending portion of the connecting member and the extending portion of the connecting member. It can also be formed so that the thickness of the resin on the other side in the plate thickness direction is the same.

  In such a semiconductor device of the present invention, the semiconductor element is a bipolar transistor arranged such that one side in the plate thickness direction is an emitter and the other side in the plate thickness direction is a collector, It can also be a member that connects one collector and the other emitter of two adjacent semiconductor elements.

It is a block diagram which shows the outline of a structure of the power converter device 20 in which the power card 26 as one Example of this invention was mounted. 2 is a configuration diagram showing an outline of a configuration of a power card 26. FIG. It is explanatory drawing which shows an example of the mode before and after a heating / cooling cycle is repeated in the power converter device 120 provided with the power card 126 of the comparative example which does not have the recessed part 26c.

  Next, the form for implementing this invention is demonstrated using an Example.

  FIG. 1 is a configuration diagram showing an outline of a configuration of a power conversion device 20 on which a power card 26 according to an embodiment of the present invention is mounted. The power converter 20 includes a power card 26 in which semiconductor elements 22 and 23 constituting a boost converter, an inverter, and the like are built in, and insulating plates 30a and 30b bonded to both surfaces of the power card 26 through heat radiation grease 28a and 28b. And a cooler 34 that is bonded to the insulating plates 30a and 30b via the heat radiation grease 32a and 32b and in which cooling water flows. In the power converter 20, the power card 26 is cooled by the cooler 34 through the heat radiating greases 28a, 28b, 32a, 32b and the insulating plates 30a, 30b.

  FIG. 2 is a configuration diagram showing an outline of the configuration of the power card 26. The power card 26 is formed in a plate shape, and includes semiconductor elements 22 and 23 arranged side by side in the left-right direction in FIG. 2 and bus bars 22g and 22h for connecting the semiconductor elements 22 and the semiconductor elements 23. I have.

  The semiconductor elements 22 and 23 include semiconductor chips 22a and 23a, spacers 22c and 23c, emitter electrodes 22e and 23e, and collector electrodes 22f and 23f.

  The semiconductor chips 22a and 23a are configured as chips on which an insulated gate bipolar transistor (IGBT) is mounted, and the upper side (one side in the plate thickness direction) of the power card 26 in FIG. It arrange | positions so that the other side of a plate | board thickness direction may become a collector.

  The spacers 22c and 23c are made of copper (Cu), and are attached to the upper emitters of the semiconductor chips 22a and 23a in the drawing via conductive solders 22b and 23b.

  The emitter electrodes 22e and 23e are attached to the spacers 22c and 23c via conductive solders 22d and 23d. The collector electrodes 22f and 23f are connected to the lower collector of the semiconductor chips 22a and 23a in the drawing.

  The bus bar 22g is formed as a plate-like member and is connected to the emitter electrode 23e. As shown in FIG. 2, the bus bar 22g is formed to extend from the emitter electrode 23e in the left direction in FIG. The bus bar 22h is formed as a plate-like member, and is connected to the collector electrode 22f and the bus bar 22g. The bus bar 22h is formed to extend straight from the collector electrode 22f toward the bus bar 22g, bend in the vicinity of the bus bar 22g, and extend parallel to the bus bar 22g. Since the bus bar 22h extends straight toward the emitter electrode 23e without being bent in the vicinity of the collector electrode 22f, the bus bar 22h is manufactured as compared with the case where the bus bar is bent at both the emitter electrode 23e and the collector electrode 22f. The bending process can be reduced. In the bus bars 22h and 22g, when the power card 26 in FIG. 2 is divided into two at a height half the plate thickness TH2, the volume in the upper part 26a on the upper side is larger than the volume in the lower part 26b on the lower side. Yes.

  In the power card 26, the semiconductor chips 22a and 23a and the conductive solder 22b are arranged so as to be flush with the resin 24 with the emitter electrodes 22e and 23e and the collector electrodes 22f and 23f of the semiconductor elements 22 and 23 exposed on the surface. 23b, 22d, 23d, spacers 22c, 23c, and bus bars 22g, 22h are molded.

  A recess 26 c is formed in the power card 26 only on the lower side in FIG. 2 and between the semiconductor element 22 and the semiconductor element 23. The recess 26c is substantially the same in shape as the cross section of the opening parallel to the plate thickness direction of the bus bar 22g, and the depth D is in the range of 20% to 40% of the plate thickness TH2 of the power card 26 (for example, the plate 20%, 30%, 40%, etc. of thickness TH2.

  Here, the reason why the recess 26 c is formed only on the lower side in FIG. 2 and between the semiconductor element 22 and the semiconductor element 23 will be described. FIG. 3 is an explanatory diagram illustrating an example of a state before and after the heating / cooling cycle is repeated in the power conversion device 120 including the power card 126 of the comparative example in which the concave portion 26c is not formed. In the power card 126, the bus bars 22h and 22g have a volume in the upper portion 26a larger than a volume in the lower portion 26b, so that the resin 24 has a volume in the lower portion 26b larger than a volume in the upper portion 26a. In such a power conversion device 120, when the heating / cooling cycle is repeated with respect to the resin 24 by the heat generated by the operation of the semiconductor chips 22a and 23a and the subsequent cooling, the larger the volume of the resin 24, that is, the power card 26 Thermal stress concentrates between the lower portion 26 b, particularly between the semiconductor elements 22 and 23, and the entire power card 126 is deformed. When the entire power card 126 is deformed, the heat dissipating grease 28a, 28b is pushed out by the power card 126 and comes out between the power card 126 and the insulating plates 30a, 30b. In general, the insulating plates 30a and 30b have lower thermal conductivity than the heat radiating greases 28a and 28b, so that the cooling efficiency by the cooler 34 is lowered.

  In the power card 26 of the embodiment, the concave portion 26c is formed on the lower side in FIG. 2 and only between the semiconductor element 22 and the semiconductor element 23, so that the volume and lower portion of the resin 24 in the upper portion 26a of the power card 26 are reduced. The difference with the volume of the resin 24 in 26b can be made small, and the concentration of thermal stress on the resin 24 due to repeated heating / cooling cycles can be suppressed. Thereby, it can suppress that a deformation | transformation arises in the power card 26 whole. Further, since deformation of the entire power card 26 is suppressed, it is possible to suppress the escape of the heat dissipation greases 28a and 28b, and it is possible to suppress a decrease in cooling efficiency by the cooler 34.

  According to the power converter 20 of the embodiment described above, the bus bars 22h and 22g are arranged such that the volume at the upper portion 26a (one side in the plate thickness direction) is larger than the volume at the lower portion 26b (the other side in the plate thickness direction). The recess 26c is formed only on the lower side (the other side in the plate thickness direction) and between the semiconductor element 22 and the semiconductor element 23, whereby the volume of the resin 24 at the upper portion 26a and the volume at the lower portion 26b. And the difference can be reduced. Thereby, concentration of thermal stress due to repeated heating / cooling cycles can be suppressed, and deformation of the entire power card 26 can be suppressed.

  In the power conversion device 20 of the embodiment, the recess 26c is substantially the same as the shape of the cross section parallel to the thickness direction of the bus bar 22g, and the depth D is 20% or more of the thickness TH2 of the power card 26. %, But the recess 26c is considered to be an integral connecting member with the bus bars 22g and 22h, and the upper side in FIG. The thickness of the resin 24 on one side in the plate thickness direction and the thickness of the resin 24 on the lower side (the other side in the plate thickness direction) may be the same.

  In the power conversion device 20 of the embodiment, the power card 26 includes the bus bar 22g connected to the emitter electrode 23e and the bus bar 22h connected to the collector electrode 22f and the bus bar 22g. It is good also as what is an integral member.

  In the power converter 20 of the embodiment, the bus bar 22g is connected to the emitter electrode 23e and the bus bar 22h is connected to the collector electrode 22f and the bus bar 22g. However, the bus bar 22g is connected to the collector electrode 22f, 22h may be connected to the emitter electrode 23e and the bus bar 22g. In this case, the recess 26 c may be formed only on the upper side in FIG. 2 and between the semiconductor element 22 and the semiconductor element 23.

  In the power conversion device of the embodiment, the recess 26c is formed only on the lower side in FIG. 2 and between the semiconductor element 22 and the semiconductor element 23, so that the volume in the lower portion 26b and the volume in the upper portion 26a of the resin 24 are obtained. However, the recess 26c may be formed so that the volume of the upper portion 26a of the resin 24 is the same as the volume of the lower portion 26b.

  In the power conversion apparatus 20 of the embodiment, the two semiconductor elements 22 and 23 are molded in the resin 24 with the emitter electrode 22e and the collector electrode 22f exposed, but three or more semiconductor elements are in the resin 24. It is good also as what is molded in. In this case, the recess 26c may be formed on the lower side in FIG. 2 and between adjacent semiconductor elements among the three or more semiconductor elements.

  Here, the correspondence between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problems will be described. In the embodiment, the semiconductor elements 22 and 23 correspond to “semiconductor elements”, the bus bars 22g and 22h correspond to “connecting members”, the resin 24 corresponds to “resin”, and the recess 26c corresponds to “recess”. .

  The correspondence between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problem is the same as that of the embodiment described in the column of means for solving the problem. Therefore, the elements of the invention described in the column of means for solving the problems are not limited. That is, the interpretation of the invention described in the column of means for solving the problems should be made based on the description of the column, and the examples are those of the invention described in the column of means for solving the problems. It is only a specific example.

  As mentioned above, although the form for implementing this invention was demonstrated using the Example, this invention is not limited at all to such an Example, In the range which does not deviate from the summary of this invention, it is with various forms. Of course, it can be implemented.

  The present invention can be used in the semiconductor device manufacturing industry.

  DESCRIPTION OF SYMBOLS 10 Power control unit 20,20 Power converter, 22,23 Semiconductor element, 22a, 23a Semiconductor chip, 22b, 22d, 23b, 23d Conductive solder, 22c, 23c Spacer, 22e, 23e Emitter electrode, 22f, 23f Collector Electrode, 22g, 22h Bus bar, 24 resin, 26, 126 Power card, 26a upper part, 26b lower part, 26c Recessed part, 28a, 28b, 32a, 32b Heat radiation grease, 30a, 30b Insulating plate, 34 Cooler.

Claims (1)

A plate-like semiconductor device in which a plurality of semiconductor elements are arranged side by side, and the plurality of semiconductor elements are connected to each other by a connecting member, and these are molded with a resin,
The connecting member is arranged so that the volume on one side in the plate thickness direction is larger than the volume on the other side,
A recess is formed only on the other side of the resin in the plate thickness direction and between two adjacent semiconductor elements among the plurality of semiconductor elements.

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