JP6139342B2 - Laminated unit - Google Patents

Description

  The technology disclosed in this specification relates to a stacked unit in which a semiconductor card and a cooling plate are stacked with an insulating plate interposed therebetween and receives a load in the stacking direction.

  In hybrid cars and electric cars, inverters and voltage converters are used to adjust the power supplied to the driving motor. Since the traveling motor has a large output, a power semiconductor element such as an IGBT used in the above-described inverter or the like generates a large amount of heat. Patent Document 1 discloses a stacked unit in which a semiconductor card in which power semiconductor elements are housed in a flat resin mold and cooling plates (flat tubes) in which a coolant flows are alternately stacked. In the stacked unit, a compressive load is applied in the stacking direction to the stacked body in which the semiconductor card and the cooling plate are stacked. Thereby, the heat transfer efficiency from the semiconductor card to the cooling plate is improved.

JP 2005-228877 A

  In a stacked unit in which a semiconductor card and a cooling plate are alternately stacked, an insulating plate may be sandwiched between the semiconductor card and the cooling plate in order to ensure insulation between the semiconductor card and the cooling plate. As a material for the insulating plate, ceramics having high insulating properties may be used. In order to ensure heat transfer, the thickness of such ceramic insulating plates is usually reduced. On the other hand, when a compressive load is applied to the stacked body in which the semiconductor card and the cooling plate are stacked, the cooling plate may be bent. In this case, the insulating plate sandwiched between the semiconductor card and the cooling plate is bent. Here, the ceramic forming the insulating plate is poor in flexibility. For this reason, there exists a possibility that an insulating board may be damaged.

  The applicant of this patent application has disclosed a technique for solving the above problems in Japanese Patent Laid-Open No. 2013-115137. In this technique, a depression is provided on the surface of the cooling plate. By providing the depression, the rigidity of the cooling plate is improved. In the technique of Patent Document 1, by suppressing the bending of the cooling plate by increasing the rigidity of the cooling plate, the bending of the insulating plate that is in contact with the cooling plate is also suppressed and is not easily damaged. Here, the rigidity of the cooling plate increases in the vicinity of the recess, but the rigidity decreases as the distance from the recess increases. The insulating plate is sandwiched between the cooling plate and the semiconductor card. However, if the insulating plate is sandwiched between the cooling plate and the edge of the semiconductor card at a low rigidity, the insulating plate may be greatly bent and deformed at the edge of the semiconductor card. The present specification provides a technique for suppressing the bending deformation of the insulating plate at such a location and making the insulating plate difficult to break.

  This specification discloses a stacked unit in which a semiconductor card and a cooling plate are stacked with an insulating plate interposed therebetween and receives a load in the stacking direction. The stacked unit suppresses the insulating plate disposed between the semiconductor card and the cooling plate from being damaged by bending at the edge of the semiconductor card with a small radius of curvature. The cooling plate is provided with a recess on the outer surface of the contact area between the semiconductor card and the insulating plate when viewed from the stacking direction on the surface on which the insulating plate is disposed. The insulating plate has a portion protruding from the contact range in the direction of the depression when viewed from the stacking direction. The semiconductor card is curved in a direction in which the edge of the surface facing the insulating plate that faces the protruding portion is separated from the insulating plate.

  In the above laminated unit, since the cooling plate is provided with the depression, the bending rigidity of the cooling plate is improved. For this reason, it is suppressed that a cooling plate bends with a compressive load. Here, since the edge of the recess of the cooling plate is higher in rigidity than other parts of the cooling plate, if the insulating plate is sandwiched between the recess and the semiconductor card, the compressive stress generated in the insulating plate becomes too high. There is. In the above-described laminated unit, the recess is provided outside the contact range between the semiconductor card and the insulating plate. For this reason, it is prevented that the compressive stress added to an insulating board becomes high.

  The insulating plate has a portion that protrudes from the contact range in the direction of the depression. For this reason, insulation between the semiconductor card and the cooling plate can be maintained even when the relative position between the semiconductor card and the cooling plate is shifted during assembly or use of the stacked unit.

  When the depression is provided in the cooling plate, the rigidity of the cooling plate in the portion where the depression is not provided is usually relatively smaller than the rigidity of the portion where the depression is provided. The contact range of the semiconductor card and the insulating plate is located on the cooling plate at a place where no depression is provided. For this reason, when a compressive load is applied, the surface of the cooling plate located in the contact range sinks inside the cooling plate, and the cooling plate may be bent. The insulating plate is sandwiched between the cooling plate and the semiconductor card. For this reason, when the cooling plate is bent, the insulating plate is bent and deformed at the edge portion of the semiconductor card.

  In the stacked unit disclosed in this specification, the semiconductor card is curved in a direction in which the edge of the surface facing the insulating plate and the protruding portion is separated from the insulating plate. In other words, the curved edge is located between the contact area and the recess of the cooling plate. For this reason, when the insulating plate is bent and deformed, the insulating plate is bent and deformed along the curved surface of the edge of the semiconductor card. As a result, the insulating plate is prevented from being bent and deformed with a curvature radius equal to or less than the curvature radius of the curved surface. Thereby, it is suppressed that an insulating board is destroyed by a compressive load.

FIG. 3 is a perspective view showing a multilayer unit 100 of Example 1. 3 is an exploded view of the cooling plate 2. FIG. They are a plan view (A) and a side view (B) showing the positional relationship among the cooling plate 2, the semiconductor card 3, and the insulating plate 4. FIG. 4 is an enlarged cross-sectional view of the laminated unit 100 of Example 1 taken along the line IV-IV in FIG. However, only the vicinity of the depression 2a located on the left side of FIG. FIG. 4 is an enlarged cross-sectional view of the laminated unit 100 of Example 1 taken along the line IV-IV in FIG. However, only the vicinity of the depression 2a located on the left side of FIG. It is an expanded sectional view which shows the lamination | stacking unit 100 of a comparative example.

  The stacked unit 100 is a unit mounted on a hybrid car, an electric vehicle, or the like. The laminated unit 100 is an integrated circuit of inverters and converters that supply alternating current power to the motor for driving, especially those elements that generate a large amount of heat, specifically, switching elements that generate alternating current, and switching elements for step-up / step-down circuits. The unit is integrated with the cooling device. The switching element is typically an IGBT. The stacked unit 100 has a structure in which a plurality of packages (semiconductor cards 3) enclosing semiconductor elements such as IGBTs and a plurality of cooling plates 2 are stacked. Both the semiconductor card 3 and the cooling plate 2 are formed in a flat plate shape. In other words, the stacked unit 100 has a structure in which a plurality of cooling plates 2 are arranged in parallel and the semiconductor card 3 is sandwiched between adjacent cooling plates 2. The cooling plate 2 is made of a metal having high thermal conductivity such as aluminum or copper. On the other hand, the semiconductor card 3 typically has a semiconductor element sealed with a resin mold. In addition, although illustration is abbreviate | omitted, the surface of the semiconductor card 3 may be equipped with the heat sink which transfers the heat | fever of an internal semiconductor element to the surface. Further, although not shown, electrodes extend from the internal semiconductor elements to the outside of each semiconductor card 3 and are connected to other circuits.

  The inside of the cooling plate 2 is a cavity (refrigerant flow path) through which the refrigerant flows. Each cooling plate 2 is provided with two through holes at both ends in the longitudinal direction, and adjacent cooling plates are connected by a connecting pipe 5. A supply pipe 8 for supplying the refrigerant and a discharge pipe 7 for discharging the refrigerant are connected to the through holes of the cooling plate located at the end of the laminate. The refrigerant supplied from the supply pipe 8 is divided into the refrigerant flow path and the connection pipe 5 in the cooling plate 2 and then flows to the downstream cooling plate 2 one after another. The refrigerant absorbs heat of the semiconductor card 3 while passing through the cooling plate and cools the semiconductor card 3. The refrigerant that has passed through the cooling plate joins through the other through hole and finally reaches the discharge pipe 7. The refrigerant is preferably a liquid, such as LLC (Long Life Coolant). A recess 2 a is provided on the surface of the cooling plate 2.

  An insulating plate 4 is sandwiched between the cooling plate 2 and the semiconductor card 3. The insulating plate 4 is made of ceramics. The laminated body of the cooling plate 2 and the semiconductor card 3 is sandwiched and fixed by the bracket 12. A plate spring 14 is disposed at one end of the bracket 12, and the plate spring 14 biases the stacked body in the stacking direction. The plate spring 14 causes the cooling plate 2, the insulating plate 4, and the semiconductor card 3 to be in close contact with each other, and high heat transfer efficiency is ensured. On the other hand, the ceramic insulating plate 4 is more fragile than a cooling plate or the like, and may be broken by the load of the leaf spring 14.

  The internal structure of the cooling plate 2 will be described with reference to FIG. The cooling plate 2 has outer plates 21 and 23 corresponding to a casing and an intermediate plate 22 sandwiched between them. The container-like outer plates 21 and 23 are formed by pressing an aluminum plate. Fins 24 made of corrugated plates are arranged inside the outer plate 21, and the intermediate plate 22 holds the fins 24. Further, fins 24 are also arranged inside the outer plate 23, and this is also suppressed by the intermediate plate 22. The fins 24 are in contact with both the intermediate plate 22 and the outer plates 21 and 23, so that the heat transmitted from the semiconductor card 3 is easily diffused throughout the cooling plate 2. Moreover, the fin 24 increases the contact area with the refrigerant flowing inside the cooling plate 2 and improves the heat transfer efficiency to the refrigerant. As shown well in FIG. 2, the depression 2 a when viewed from the outside corresponds to a rib when viewed from the inside of the outer plates 21 and 23, and increases the rigidity of the outer plates 21 and 23.

  The advantages of the recess 2a will be described. The cooling plate 2 is an aluminum plate formed into a container shape by pressing. Therefore, the rigidity is low. The recess 2 a corresponds to a rib when viewed from the inside of the cooling plate 2 and plays a role of increasing the rigidity of the cooling plate 2. Therefore, the cooling plate 2 becomes difficult to bend even if it receives a load in the stacking direction. When the cooling plate 2 is bent, the contact area between the semiconductor card 3 and the cooling plate 2 decreases. In the laminated unit 100 of the present embodiment, since the cooling plate 2 is difficult to bend, it is possible to prevent the cooling performance of the semiconductor card 3 from being lowered.

  The positional relationship between the cooling plate 2, the semiconductor card 3, and the insulating plate 4 will be described with reference to FIGS. 3 (A) and 3 (B). FIG. 3A is a view of the semiconductor card 3, the insulating plate 4, and the cooling plate 2 when viewed in the stacking direction. As shown in FIG. 3A, the semiconductor card 3 is arranged at a position between the depressions 2a on both sides in the longitudinal direction of the cooling plate 2 (left and right direction in the figure). In other words, the recess 2 a is provided outside the contact area between the semiconductor card 3 and the insulating plate 4. The insulating plate 4 is sandwiched between the semiconductor card 3 and the cooling plate 2 in the vertical direction of FIG.

  Next, the configuration of the laminated unit 100 around the recess 2a will be described in more detail with reference to FIGS. 4 and 5 show the periphery of the recess 2a located at the lower left of the semiconductor card 3 in FIG. Since the depression 2a at the other position is the same as the depression 2a, the description thereof is omitted.

  The recess 2a is provided outside the contact area between the semiconductor card 3 and the insulating plate 4 (left side in FIG. 4). The insulating plate 4 has a portion 4a protruding from the contact range between the semiconductor card 3 and the insulating plate 4 in the direction of the recess 2a (left direction in FIG. 4). As shown in FIG. 4, the lower surface of the semiconductor card 3 (the surface on the side where the insulating plate 4 is disposed) has a flat surface 3b and a curved surface 3c. The curved surface 3 c is formed on the edge of the lower surface of the semiconductor card 3 on the side of the depression 2 a. In other words, the edge of the lower surface of FIG. 4 of the semiconductor card 3 (the edge facing the protruding portion 4 a) is curved in a direction away from the insulating plate 4.

  As described above, in the stacked unit 100, a compressive load is applied in the stacking direction of the semiconductor cards 3. Here, since the edge of the recess 2a is higher in rigidity than the other portions of the cooling plate 2, if the insulating plate 4 is sandwiched between the recess 2a and the semiconductor card 3, the compressive stress generated in the insulating plate 4 is high. It may become too much. In the laminated unit 100 of the present embodiment, the recess 2 a is provided outside the contact range of the semiconductor card 3 and the insulating plate 4. For this reason, it is prevented that the compressive stress added to the insulating plate 4 becomes high.

  The insulating plate 4 has a portion 4a protruding from the contact range between the semiconductor card 3 and the insulating plate 4 in the direction of the recess 2a. Therefore, insulation between the semiconductor card 3 and the cooling plate 2 can be maintained even when the relative position between the semiconductor card 3 and the cooling plate 2 is shifted when the laminated unit 100 is assembled or used.

  When the depression 2a is provided in the cooling plate 2, the rigidity of the cooling plate 2 in the part where the depression 2a is not provided may be relatively smaller than the rigidity of the part where the depression 2a is provided. In this case, the contact range of the semiconductor card 3 and the insulating plate 4 is located in a portion where the rigidity of the cooling plate 2 is low (a portion where the recess 2a is not provided). For this reason, when a compressive load is applied, as shown in FIG. 5, the upper surface in FIG. 5 of the cooling plate located in the contact range sinks to the lower side (inside the cooling plate 2). 2 may bend. The insulating plate 4 is sandwiched between the cooling plate 2 and the semiconductor card 3. For this reason, when the cooling plate 2 is bent, the insulating plate 4 is bent and deformed at the edge portion of the semiconductor card 3.

  In the laminated unit 100 of the present embodiment, the semiconductor card 3 has a curved surface 3c formed at the edge on the depression 2a side on the surface on which the insulating plate 4 is disposed. For this reason, when the insulating plate 4 is bent and deformed, the insulating plate 4 is deformed along the curved surface 3 c of the semiconductor card 3. As a result, the insulating plate 4 is prevented from being bent and deformed with a curvature radius equal to or less than the curvature radius of the curved surface 3c formed on the semiconductor card. Thereby, it is suppressed that the insulating plate 4 is destroyed by the compressive load.

  Below, the comparative example of the lamination | stacking unit 100 of Example 1 is demonstrated using FIG. The laminated unit 100 of the comparative example is obtained by changing the semiconductor card 3 of the laminated unit 100 of Example 1 to the semiconductor card 53. In the laminated unit 100 of the comparative example, unlike the first embodiment, the curved surface 3c is not formed at the edge of the recess on the surface where the insulating plate 4 of the semiconductor card 53 is disposed. Therefore, the insulating plate 4 is bent and deformed with a relatively small radius of curvature at the edge of the semiconductor card 53 (lower left edge in FIG. 6). As a result, in the laminated unit 100 of the comparative example, the insulating plate 4 is easily broken by the compressive load of the laminated unit 100.

  In the above embodiment, the curved surface 3c is a cylindrical surface. However, the curved surface 3c may be a curved surface other than the cylindrical surface. Further, in the above embodiment, in the cross-sectional shape shown in FIG. 4, the line corresponding to the lower surface of the semiconductor card 3 is a tangent to the arc corresponding to the curved surface 3c, and the side surface of the semiconductor card 3 (the left side surface in FIG. 4). ) Intersects with the arc corresponding to the curved surface 3c. However, both the line corresponding to the lower surface of the semiconductor card 3 and the line corresponding to the side surface of the semiconductor card 3 may be tangents of the arc corresponding to the curved surface 3c. In other words, the curved surface 3c may have the same shape as a so-called R chamfer. However, as in the above embodiment, the line corresponding to the lower surface of the semiconductor card 3 is a tangent to the arc corresponding to the curved surface 3c, and the line corresponding to the side surface of the semiconductor card 3 is an arc corresponding to the curved surface 3c. When intersecting, the curved surface 3c has the following advantages compared to the case where the curved surface 3c has the same shape as the R chamfer. That is, in the case of the shape as in the above embodiment, it is possible to increase the contact area between the semiconductor card 3 and the cooling plate 2 while increasing the radius of curvature of the curved surface 3c. Thereby, the cooling performance of the semiconductor card 3 can be improved while suppressing the destruction of the insulating plate 4.

  Specific examples of the present invention have been described in detail above, 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. In addition, the technical elements described in the present specification or drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology exemplified in the present specification or the drawings can achieve a plurality of objects at the same time, and has technical utility by achieving one of the objects.

2 Cooling plate 3 Semiconductor card 3b Flat surface 3c Curved surface 4 Insulating plate 4a Portion of the insulating plate that protrudes in the direction of the recess 100 Laminated unit

Claims (1)

A semiconductor card and a cooling plate are laminated with an insulating plate in between and a laminated unit that receives a load in the lamination direction,
The cooling plate is a surface on the side where the insulating plate is disposed, and a recess is provided outside the contact range of the semiconductor card and the insulating plate when viewed from the stacking direction.
The insulating plate has a portion protruding from the contact range in the direction of the depression when viewed from the stacking direction,
The semiconductor card is a stacked unit in which an edge of a surface facing the insulating plate and an edge facing the protruding portion is curved in a direction away from the insulating plate.

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