JP2019003971A - Semiconductor device - Google Patents

Abstract

To provide a technique for holding a dielectric plate 30 before lamination without applying grease between a power card 20 and the dielectric plate 30, in a semiconductor device 2 where the power card 20 and a cooler 10 are laminated while sandwiching the dielectric plate 30.SOLUTION: In a semiconductor device 2, a power card 20 where a semiconductor element 41 is sealed and a cooler 10 are laminated while sandwiching a dielectric plate 30, and a load is applied in the lamination direction. The power card 20 has locking parts 25a, 25b in contact with the edge of the dielectric plate 30, and the surface facing the cooler 10. The locking parts 25a, 25b hold the dielectric plate 30 for the power card 20 before lamination with the cooler 10. Consequently, in the manufacturing process of the semiconductor device 2, the step of coating the power card 20 with grease is reduced, and manufacturing cost of the semiconductor device 2 can be reduced.SELECTED DRAWING: Figure 2

Description

  The technology disclosed in this specification relates to a semiconductor device in which a power card in which semiconductor elements are sealed and a cooler are stacked with an insulating plate interposed therebetween.

  A double-sided cooling structure is known as a structure for cooling a semiconductor element (for example, Patent Document 1). Patent Document 1 discloses a power card stacked unit (semiconductor device) including a power card in which a semiconductor element is sealed and a cooler disposed on both sides of the power card via insulating plates. In the semiconductor device of Patent Document 1, grease is applied between the power card and the insulating plate.

JP 2016-1111176 A

  In the semiconductor device disclosed in Patent Document 1, grease functions as a heat transfer material that increases the heat transfer efficiency from the power card to the cooler, and bonds an insulating plate to the power card before stacking the power card and the cooler. Functions as an adhesive. In the semiconductor device disclosed in Patent Document 1, a function as an adhesive is required even if a function as a heat transfer material is unnecessary, and thus a process of applying grease is required in the manufacturing process. If the insulating plate can be held on the surface of the power card without grease before being stacked with the cooler, the step of applying grease becomes unnecessary, and the manufacturing cost of the semiconductor device can be reduced.

  In this specification, a power card in which a semiconductor element is sealed and a cooler are stacked with an insulating plate interposed therebetween, and a load is applied to the power card and the cooler along the stacking direction. An apparatus is disclosed. The power card of the semiconductor device has a locking portion that contacts the edge of the insulating plate and contacts the surface of the insulating plate facing the cooler to lock the insulating plate. According to the semiconductor device of this aspect, the locking portion holds the insulating plate with respect to the power card. Therefore, the semiconductor device disclosed in this specification does not require grease as an adhesive. This semiconductor device can reduce the step of applying grease to the power card in the manufacturing process, and can reduce the manufacturing cost of the semiconductor device.

It is a perspective view of a semiconductor device in an example. It is sectional drawing in alignment with the II-II line | wire in FIG. 1 of the power card, the insulating board arrange | positioned on both surfaces, and a cooler. It is the front view which looked at the power card when attaching an insulating board to a package from the X-axis positive direction.

  FIG. 1 is a perspective view of a semiconductor device 2 in the embodiment. The semiconductor device 2 shown in FIG. 1 has a structure in which a plurality of power cards 20, a plurality of insulating plates 30, and a plurality of coolers 10 are stacked. In FIG. 1, one power card 20 among the plurality of power cards 20 included in the semiconductor device 2 and the insulating plates 30 disposed on both surfaces of the power card 20 are drawn out. In FIG. 1, reference numeral 20 is attached to only one power card, and reference numerals are omitted for the other power cards. Similarly, in FIG. 1, the code | symbol 10 is attached | subjected only to one cooler, and the code | symbol is abbreviate | omitted in the other cooler. Further, the reference numeral 30 is attached only to the two insulating plates drawn and drawn, and the reference numerals are omitted for the other insulating plates.

  As shown in FIG. 1, the semiconductor device 2 includes a case 6, a leaf spring 7, and a stacked unit 8. The case 6 accommodates the leaf spring 7 and the laminated unit 8. In this embodiment, the case 6 has a hollow rectangular parallelepiped shape. In addition, the case 6 should just be able to accommodate the lamination | stacking unit 8, and the shape of case 6 is not restricted to a rectangular parallelepiped. The leaf spring 7 applies a load in the stacking direction to the stacking unit 8. Here, the stacking direction is the direction in which the power card 20 and the cooler 10 are stacked, and the X-axis direction of the coordinate system in the figure corresponds to this. By applying a load in the stacking direction to the stacking unit 8, the adhesion of the power card 20, the insulating plate 30, and the cooler 10 is enhanced, and heat transfer characteristics from the power card 20 to the cooler 10 are improved.

  Hereinafter, the axis parallel to the stacking direction is defined as the X axis, and the left side of FIG. 1 is defined as the positive direction of the X axis. The Z axis is defined as an axis parallel to the vertical direction in FIG. 1, and the vertically upward direction is defined as the positive direction of the Z axis. An axis orthogonal to the X axis and the Z axis is defined as the Y axis, and the front direction in FIG. 1 is defined as the positive direction of the Y axis.

  The stacked unit 8 includes a plurality of power cards 20, a plurality of coolers 10, a plurality of insulating plates 30, connection pipes 4a and 4b that connect the plurality of coolers 10 along the stacking direction, and a refrigerant supply pipe 3a. And a refrigerant discharge pipe 3b.

  The power card 20 is a flat plate type, and is arranged such that flat surfaces having the largest areas among a plurality of side surfaces face each other. Insulating plates 30 are arranged so as to face both surfaces of the power card 20 in the stacking direction. Hereinafter, in each member, a surface parallel to the YZ plane orthogonal to the stacking direction (X-axis direction) may be referred to as a stacking surface.

  The cooler 10 is arrange | positioned so that the power card 20 with which the insulating board 30 is arrange | positioned on both the lamination surfaces may be pinched | interposed. In other words, the power card 20 and the cooler 10 are stacked with the insulating plate 30 interposed therebetween. The laminated surface of the cooler 10 is larger than the laminated surface of the power card 20 and the laminated surface of the insulating plate 30.

  All the coolers 10 are connected by the connecting pipe 4a in the negative Y-axis direction of the portion of the stacked surface of the cooler 10 where the stacked surfaces of the insulating plates 30 do not overlap. The connecting pipe 4a is connected to the refrigerant supply pipe 3a via the cooler 10 located at the end in the positive direction of the X axis. Similarly, all the coolers 10 are connected by the connecting pipe 4b in the positive Y-axis direction of the portion where the stacked surfaces of the insulating plates 30 do not overlap among the stacked surfaces of the coolers 10. The connecting pipe 4b is connected to the refrigerant discharge pipe 3b via the cooler 10 located at the end in the X-axis positive direction. The refrigerant supply pipe 3a and the refrigerant discharge pipe 3b are connected from the outside of the case 6 to the cooler 10 located at the end in the X-axis positive direction in the laminated unit 8. The connection pipe 4a and the refrigerant supply pipe 3a are circular pipes arranged coaxially with respect to a straight line extending in the stacking direction. The connection pipe 4b and the refrigerant discharge pipe 3b are also circular pipes arranged coaxially with respect to a straight line extending in the stacking direction. With such a configuration, the refrigerant supplied from the refrigerant supply pipe 3a is supplied to the plurality of coolers 10 through the connection pipe 4a, and passes through the refrigerant discharge pipe 3b from the plurality of coolers 10 through the connection pipe 4b. Discharged. Heat is absorbed from the power card 20 stacked with the cooler 10 and the insulating plate 30 interposed therebetween by the refrigerant passing through the inside of the cooler 10.

  As shown in FIG. 1, one power card 20 has a plurality of semiconductor elements (illustrated later in FIG. 2) inside. The semiconductor element is a flat chip, and is disposed inside the power card 20 so that the flat surface of the semiconductor element is parallel to the YZ plane. The semiconductor element is, for example, a transistor or a diode. The power card 20 includes a package 25, three electrode terminals 26a, 26b, 26c extending from the package 25 in the Z-axis positive direction, and two control terminal groups 29a extending from the package 25 in the Z-axis negative direction. 29b and two heat sinks 23a and 23b exposed on the laminated surface. The heat radiating plates 23 a and 23 b are formed on both surfaces of the package 25. The heat sinks 23a and 23b are joined to the semiconductor element inside the package 25 via solder. In the laminated unit 8, the laminated surfaces of the heat radiating plates 23 a and 23 b are in contact with the laminated surfaces of the opposing insulating plates 30. The heat sinks 23a and 23b are formed of a material (for example, copper) that is excellent in conductivity and heat transfer.

  Each of the electrode terminals 26a, 26b, and 26c has a flat plate shape. Each of the electrode terminals 26a, 26b, and 26c is connected to an upper end (Z-axis positive direction side) of a semiconductor element disposed inside the package 25. Each of the control terminal groups 29a and 29b is composed of three rod-shaped terminals. Each of the control terminal groups 29 a and 29 b is connected to the lower end (Z-axis negative direction side) of the semiconductor element disposed inside the package 25. The detailed shape of the package 25 will be described later together with the description of FIG.

  The insulating plate 30 is made of a material (for example, heat conductive ceramics) having high insulation and excellent heat conductivity. The insulating plate 30 insulates the power card 20 and the cooler 10 when stacked as the stacked unit 8 and transmits heat of the semiconductor elements released from the heat radiating plates 23 a and 23 b to the cooler 10. The insulating plate 30 is fixed to the package 25 by a locking portion of the package 25 described later. The insulating plate 30 fixed to the locking portion and the package 25 will be described later together with the description of FIGS.

  2 is a cross-sectional view of the power card 20, the insulating plates 30 disposed on both surfaces of the power card 20, and the cooler 10 along the line II-II in FIG. As shown in FIG. 2, one cooler 10 includes a flat middle plate 15, two outer plates 16 and two corrugated fin plates 19 arranged symmetrically around the middle plate 15. Have. The outer plate 16 has a tray shape whose peripheral edge is bent at a right angle. The middle plate 15 is sandwiched between the two outer plates 16, and the middle plate 15 and the outer plate 16 are joined so as to create a space between the middle plate 15 and the outer plate 16. One fin plate 19 is disposed in each of the two spaces formed by the intermediate plate 15 and the outer plates 16 on both sides thereof. The refrigerant flows through the space where the fin plate 19 is disposed. In the present embodiment, the intermediate plate 15, the outer plate 16, and the fin plate 19 are each made of aluminum and manufactured by pressing.

  Inside the package 25, a semiconductor element 41 and a conductive spacer 42 are disposed. The semiconductor element 41 has electrodes on both surfaces along the X axis that is the stacking direction. The laminated surface on the X axis positive direction side of the semiconductor element 41 is joined to the heat sink 23b. The stacked surface on the X axis negative direction side of the semiconductor element 41 is joined to the stacked surface on the X axis square side of the spacer 42. The laminated surface on the X axis negative direction side of the spacer 42 is joined to the heat sink 23c. Although not shown in FIG. 1, the heat radiating plate 23 c is arranged on the opposite laminated surface on which the heat radiating plate 23 b is arranged so as to correspond to the heat radiating plate 23 b in one power card 20. The package 25 is made by injection molding of resin. The semiconductor element 41 and the spacer 42 are sealed inside the package 25 by resin injection molding.

  The package 25 has locking portions 25a and 25b on the outer peripheral edge of the laminated surface. The locking portion 25a is formed on the stacked surface of the package 25 on the X axis positive direction side, and the locking portion 25b is formed on the stacked surface of the package 25 on the X axis negative direction side. In the present embodiment, the locking portion 25 a is provided over the entire length of the edge on the Z-axis positive direction side and the entire length of the edge on the Z-axis negative direction side on the stacked surface of the package 25. Furthermore, the latching | locking part 25a is provided over the full length of the edge of the Y-axis negative direction side. In other words, the locking portion 25a is formed on the outer peripheral edge of the laminated surface excluding the edge on the Y axis positive direction side. In other words, the locking portion 25a is formed to have a U shape when the stacked unit 8 is viewed from the stacking direction.

  The locking portion 25a includes an extending portion 25a1 extending along the stacking direction, and a claw portion extending in parallel with the YZ plane from the end of the extending portion 25a1 toward the center of the stacking surface of the package 25. 25a2. As shown in FIG. 2, in this embodiment, the distance between the surface on the negative side in the X axis direction of the claw portion 25a2 and the laminated surface where the heat radiating plate 23b is exposed is the thickness along the laminated direction of the insulating plate 30. It is formed to be the same. Therefore, when the insulating plate 30 is attached to the package 25, the position of the insulating plate 30 in the stacking direction is fixed by the claw portion 25a2 of the locking portion 25a. In other words, the position of the insulating plate 30 relative to the power card 20 is defined in the stacking direction. In the present embodiment, the distance between the Z-axis positive direction side extension portion 25a1 and the Z-axis negative direction side extension portion 25a1 is the same as the Z-axis dimension on the laminated surface of the insulating plate 30, The position of the insulating plate 30 in the Z-axis direction is defined by the extending portion 25a1. In other words, the extending portion 25a1 of the locking portion 25a is in contact with the edge of the insulating plate 30, and the claw portion 25a2 of the locking portion 25a is in contact with the surface of the insulating plate 30 facing the cooler 10. The three edges of the insulating plate 30 are locked by the locking portions 25a.

  The locking part 25b is formed symmetrically with the locking part 25a with respect to the YZ plane passing through the center of the package 25. Therefore, in the present embodiment, the description of the locking portion 25b is omitted. Note that all of the plurality of power cards 20 include locking portions 25a and 25b.

  FIG. 3 is a front view of the package 25 when the insulating plate 30 is mounted as seen from the positive direction of the X axis. In FIG. 3, the insulating plate 30 is hatched for easy understanding. When the insulating plate 30 is attached to the package 25, the insulating plate 30 includes the laminated surface and the claws where the heat radiating plates 23a and 23b are exposed from the Y axis positive direction side of the package 25 where the locking portion 25a is not formed. It is inserted between the portions 25a2 along the arrow CS in the negative Y-axis direction. The insulating plate 30 is inserted until it contacts the extending portion 25a1 on the Y-axis negative direction side, whereby the position in the Y-axis direction is defined.

  As described above, in the semiconductor device 2 of the present embodiment, the power card 20 having the semiconductor element 41 and the cooler 10 are stacked with the insulating plate 30 interposed therebetween. A load is applied to the laminated unit 8 including the power card 20 and the insulating plate 30 by the leaf spring 7 along the lamination direction. The package 25 of the power card 20 has locking portions 25a and 25b on the outer peripheral edge of the laminated surface. The locking portions 25a and 25b define the position of the insulating plate 30 with respect to the power card 20 in the stacking direction. In other words, the power card 20 (package 25) is provided with the locking portions 25a and 25b that are in contact with the edge of the insulating plate 30 and are in contact with the surface of the insulating plate 30 that faces the cooler 10 to lock the insulating plate 30. It has been. The locking portions 25a and 25b are provided on two parallel sides of the laminated surface of the power card 20 (package 25) and one side orthogonal to the two sides. The locking portions 25 a and 25 b can hold the insulating plate 30 against the power card 20 before being stacked with the cooler 10. Therefore, in the semiconductor device 2 of the present embodiment, an adhesive (for example, grease) that adheres the insulating plate 30 to the power card 20 before the cooler 10 is stacked becomes unnecessary. Thereby, in the manufacturing process of the semiconductor device 2, the process of applying grease between the power card 20 and the insulating plate 30 can be omitted, and the manufacturing cost of the semiconductor device 2 can be reduced.

  In the above embodiment, an example of the locking portions 25a and 25b of the power card 20 has been described. However, the locking portions 25a and 25b can be variously modified. In the above embodiment, the locking portions 25a and 25b are formed on the entire circumference excluding the edge on the Y axis positive direction side. However, in other embodiments, for example, the total length of the edge on the Z axis positive direction side and the Z axis It is formed over the entire length of the edge on the negative direction side and need not be formed on the edge in the Y-axis direction. Or conversely, it is formed over the entire length of the edge on the Y-axis positive direction side and the entire length of the edge on the Y-axis negative direction side, and may not be formed on the edge in the Z-axis direction. The locking portions 25a and 25b only need to be provided on two parallel sides of the power card 20 laminated surface. Further, the locking portions 25a and 25b may be provided not at the entire length of one edge of the stacked surface of the package 25 but at one place of the edges or may be provided discretely at several places.

  In addition, the locking portion 25a and the locking portion 25b may have different shapes, or in the plurality of power cards 20, the locking portions 25a and 25b may have different shapes. In the above embodiment, the package 25 is formed by injection molding, but may be manufactured by other molding methods. For example, the locking portions 25a and 25b may be attached after the injection molding of the package 25.

  In the present embodiment, the distance between the surface on the negative side in the X axis direction of the claw portion 25a2 and the laminated surface where the heat radiating plate 23b is exposed is the same as the thickness along the laminated direction of the insulating plate 30. However, the dimensional relationship between the distance and the thickness of the insulating plate 30 can be variously modified. For example, the insulating plate 30 may be easily attached to the package 25 by making the distance about 5% larger than the thickness of the insulating plate 30. In this case, the insulating plate 30 is held with respect to the package 25 after having a certain gap with respect to the package 25. When the laminated unit 8 is loaded in the laminating direction by the leaf spring 7, the insulating plate 30 is in close contact with the power card 20 and the cooler 10.

  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. The technical elements described in this specification or the 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 this specification or the drawings can achieve a plurality of objects at the same time, and has technical usefulness by achieving one of the objects.

2: Semiconductor device 3a: Refrigerant supply pipe 3b: Refrigerant discharge pipe 4a, 4b: Connection pipe 6: Case 7: Leaf spring 8: Laminated unit 10: Cooler 15: Middle plate 16: Outer plate 19: Fin plate 20: Power Card 21: Housings 23a, 23b, 23c: Heat radiation plate 25: Package 25a, 25b: Locking portion 25a1: Extension portion 25a2: Claw portion 26a: Electrode terminal 29a: Control terminal group 30: Insulating plate 41: Semiconductor element 42 :Spacer

Claims (1)

A semiconductor device in which a power card in which a semiconductor element is sealed and a cooler are stacked with an insulating plate interposed therebetween, and a load is applied to the power card and the cooler along a stacking direction. And
The power card includes a locking portion that contacts an edge of the insulating plate and contacts a surface of the insulating plate facing the cooler to lock the insulating plate.

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