JP6555177B2 - Semiconductor module - Google Patents

Description

  The present invention relates to a semiconductor module used for a power conversion device or the like.

  A vehicle such as an electric vehicle or a hybrid vehicle is equipped with a power conversion device that performs power conversion between DC power and AC power. As a semiconductor module used in the power conversion device, Patent Document 1 discloses a semiconductor module having a semiconductor element and a wiring board on which the semiconductor element is mounted.

  The semiconductor element generates heat due to a controlled current flowing through the semiconductor element. Therefore, the semiconductor module thermally connects a heat sink to the wiring board. As a result, the semiconductor module attempts to radiate the heat of the semiconductor element to the heat radiating plate.

JP 2012-195374 A

  However, in the semiconductor module described in Patent Document 1, the entire heat sink may be heated due to heat received from the semiconductor element. Therefore, for example, there is a risk of causing thermal degradation of the resin member that holds the heat sink. In addition, for example, when an electronic component that is weak against heat is disposed in a region close to the heat sink, the electronic component may be heated by heat of the heat sink.

  In addition, the semiconductor module described in Patent Document 1 has room for improvement from the viewpoint of improving the heat dissipation of the semiconductor element.

  In order to avoid the above-mentioned problem, it is conceivable to increase the size of the heat radiating plate to secure the heat capacity of the heat radiating plate, and to suppress the temperature rise of the heat radiating plate. However, this increases the size of the semiconductor module.

  The present invention has been made in view of such a problem, and provides a semiconductor module capable of suppressing a temperature increase in the outer peripheral portion of the heat radiating plate and improving the heat dissipation of the semiconductor element without causing an increase in size. It is something to try.

One aspect of the present invention is a wiring board (2) in which wiring patterns (221, 222, 223, 224) are formed on an insulating layer (21);
A semiconductor element (3) mounted on the wiring board;
A heat sink (4) disposed on the surface of the wiring board opposite to the semiconductor element,
The heat sink has a gap (41) that is open at least on the surface opposite to the wiring board.
The gap is formed so as to surround the semiconductor element when viewed from the normal direction (Z) of the wiring board .
In the gap, the semiconductor module (1) is provided with an anisotropic member (8) having a higher heat transfer property in the normal direction than in the plane direction perpendicular to the normal direction .
Another aspect of the present invention provides a wiring board (2) in which wiring patterns (221, 222, 223, 224) are formed on an insulating layer (21);
A semiconductor element (3) mounted on the wiring board;
A heat sink (4) disposed on the surface of the wiring board opposite to the semiconductor element;
A power terminal (6),
The heat sink has a gap (41) that is open at least on the surface opposite to the wiring board.
The gap is formed so as to surround the semiconductor element when viewed from the normal direction (Z) of the wiring board.
The semiconductor element is connected to the power terminal via a connection conductor (7) at an electrode opposite to the wiring board in the semiconductor element,
The semiconductor module (1) is provided with a heat transfer conductor (12) that thermally connects the connection conductor and the wiring board at a position overlapping the gap and the normal direction.

  In the semiconductor module, the gap is formed in a heat sink. And the space | gap part is formed so that a semiconductor element may be enclosed, when it sees from the normal line direction of a wiring board. Thereby, it can prevent that the whole heat sink becomes high temperature by the heat receiving from a semiconductor element. That is, the heat transmitted from the semiconductor element to the heat radiating plate is hardly transmitted to the outside of the region surrounded by the gap in the heat radiating plate. Therefore, it can suppress that the area | region outside the area | region enclosed by the space | gap part in a heat sink becomes high temperature.

  Further, the gap portion is opened at least on the surface opposite to the wiring board. Therefore, the heat transmitted from the semiconductor element to the heat sink can be released not only from the surface of the heat sink opposite to the wiring board but also from the gap. Therefore, the heat dissipation of the semiconductor element can be improved.

  Moreover, in the said semiconductor module, it is not necessary to enlarge especially a heat sink, and the above-mentioned effect can be acquired.

As described above, according to the above aspect, it is possible to provide a semiconductor module that can suppress an increase in the temperature of the outer peripheral portion of the heat radiating plate and improve the heat dissipation of the semiconductor element without causing an increase in size.
In addition, the code | symbol in the parenthesis described in the means to solve a claim and a subject shows the correspondence with the specific means as described in embodiment mentioned later, and limits the technical scope of this invention. It is not a thing.

FIG. 3 is a top view of the semiconductor module according to the first embodiment. The bottom view of the semiconductor module in Embodiment 1. FIG. FIG. 3 is a cross-sectional view taken along line III-III in FIG. 1. The circuit diagram which shows the power converter device in which the semiconductor module in Embodiment 1 is used. The bottom view of the semiconductor module in Embodiment 2. FIG. Sectional drawing parallel to the normal line direction which passes along the semiconductor element of the semiconductor module in Embodiment 2. FIG. The front view of the semiconductor module in Embodiment 3. FIG. The VIII-VIII arrow directional cross-sectional view of FIG. Sectional drawing which passes along the semiconductor element of the semiconductor module in Embodiment 4, and is parallel to a normal line direction.

(Embodiment 1)
An embodiment of a semiconductor module will be described with reference to FIGS.
As shown in FIGS. 1 and 3, the semiconductor module 1 of this embodiment includes a wiring board 2, a semiconductor element 3, and a heat sink 4. In the wiring substrate 2, wiring patterns 221 and 222 are formed on the insulating layer 21. The semiconductor element 3 is mounted on the wiring board 2. The heat sink 4 is arranged on the surface of the wiring board 2 opposite to the semiconductor element 3. The heat sink 4 is formed with a gap 41 that is open at least on the surface opposite to the wiring board 2. The gap 41 is formed so as to surround the semiconductor element 3 when viewed from the normal direction Z of the wiring board 2. In FIG. 1, the formation range of the gap 41 is indicated by a broken line.

  Hereinafter, the normal direction Z of the wiring board 2 is simply referred to as a normal direction Z. In the present embodiment, for the sake of convenience, one of the normal direction Z is defined as the upper side and the other as the lower side.

  As shown in FIG. 4, the semiconductor module 1 of the present embodiment can be used for a power conversion device 5 mounted on an electric vehicle, a hybrid vehicle, or the like. The power conversion device 5 is configured to perform power conversion between the DC power supply 51 and the AC load 52. And the power converter device 5 shall have the three semiconductor modules 1. FIG.

  As shown in FIG. 1, the semiconductor module 1 of this embodiment is a so-called 2-in-1 type semiconductor module 1 including a positive-side semiconductor element 31 and a negative-side semiconductor element 32 as semiconductor elements 3. Each semiconductor element 3 is made of an IGBT (that is, an insulated gate bipolar transistor). As shown in FIG. 3, each semiconductor element 3 has a collector on the lower surface and an emitter on the upper surface.

  As shown in FIGS. 1 and 3, the semiconductor element 3 is disposed on the upper surface of the wiring board 2. The wiring board 2 includes an insulating layer 21, wiring patterns 221 and 222, and a conductor layer 23.

  The insulating layer 21 has a plate shape and has a thickness in the normal direction Z. It is a layer having electrical insulation. The insulating layer 21 can be a ceramic substrate, for example.

  The wiring patterns 221 and 222 are layers formed by patterning on the upper surface of the insulating layer 21. The wiring pattern 221 and the wiring pattern 222 are arranged apart from each other on the upper surface of the insulating layer 21. As shown in FIG. 1, the positive semiconductor element 31 is disposed on the upper surface of the wiring pattern 221, and the negative semiconductor element 32 is disposed on the upper surface of the wiring pattern 222.

As shown in FIG. 3, a conductor layer 23 is bonded to the lower surface of the insulating layer 21. The conductor layer 23 may be formed, for example, from copper in a plate shape.
The insulating layer 21, the wiring patterns 221, 222, and the conductor layer 23 are all configured to be able to conduct heat.

  The lower surface of the conductor layer 23 of the wiring board 2 is joined to the upper surface of the heat sink 4. The heat sink 4 is configured to be able to conduct heat. The heat sink 4 has a substantially plate shape in which the thickness direction is the normal direction Z. The heat sink 4 is made of copper.

  As described above, the air gap 41 is formed in the heat radiating plate 4. As shown in FIGS. 1 and 2, the gap 41 is formed so as to surround both the semiconductor elements 3 of the positive-side semiconductor element 31 and the negative-side semiconductor element 32 from the entire circumference when viewed from the normal direction Z. Yes. Further, when viewed from the normal direction Z, the gap 41 has an annular shape. When viewed from the normal direction Z, both the positive-side semiconductor element 31 and the negative-side semiconductor element 32 are disposed inside the annular gap 41. When viewed from the normal direction Z, the entire gap 41 is formed outside the semiconductor element 3. In other words, the semiconductor element 3 and the gap 41 are arranged at positions that do not overlap in the normal direction Z. As shown in FIG. 3, in the present embodiment, the gap 41 is formed so as to penetrate the heat radiating plate 4 in the normal direction Z. In other words, the heat radiating plate 4 is formed with a gap 41 that opens toward both sides in the normal direction Z.

  As shown in FIG. 3, when two virtual straight lines VL defined below are assumed in a cross section parallel to the normal direction Z passing through the semiconductor element 3 (hereinafter referred to as a parallel cross section as appropriate), at least one of the gap portions 41 is assumed. The part is formed in a region outside the region between the two virtual straight lines VL in the heat radiating plate 4. FIG. 4 shows an example of a parallel cross section. Two virtual straight lines VL are represented by broken lines in FIG.

  The two virtual straight lines VL are virtual straight lines drawn on an arbitrary parallel cross section. The two imaginary straight lines VL extend obliquely downward from both ends 33 of the lower surface of the semiconductor element 3, and incline so as to increase the distance between them toward the lower side. Yes. The angle θ formed between each virtual straight line VL and the straight line NL extending in the normal direction Z is 45 °. In the parallel cross section in which a plurality of semiconductor elements 3 exist, the above-mentioned “both ends 33 of the lower surface of the semiconductor element 3” that are the starting points of the two virtual lines VL are a pair of semiconductor elements arranged at both ends. The one end of the lower surface of the semiconductor element on one side and the end of the other side of the lower surface of the semiconductor element on the other side in FIG.

  In the parallel section, a part of the gap 41 is formed in a region outside the region between the two virtual straight lines VL in the heat radiating plate 4. In the present embodiment, in the parallel section, the other part of the gap 41 is formed in the region between the two virtual straight lines VL in the heat radiating plate 4, but is not limited thereto. At least a part of the gap 41 is formed in a region outside the region between the two imaginary straight lines VL in the heat sink 4 in any parallel cross section parallel to the normal direction Z passing through the semiconductor element 3.

  As shown in FIG. 1, the semiconductor module 1 has a power terminal 6. The power terminal 6 has a positive terminal 61, a negative terminal 62, and an output terminal 63. The positive electrode terminal 61 and the negative electrode terminal 62 are arranged on the same side in one direction orthogonal to the normal direction Z with respect to the positive electrode side semiconductor element 31 and the negative electrode side semiconductor element 32. The output terminal 63 is disposed on the opposite side of the positive electrode terminal 61 and the negative electrode terminal 62 with the positive electrode side semiconductor element 31 and the negative electrode side semiconductor element 32 interposed therebetween in the one direction orthogonal to the normal direction Z.

  As shown in FIGS. 1 and 3, the semiconductor element 3 is connected to the power terminal 6 via the connection conductor 7 at the electrode on the opposite side of the wiring substrate 2 in the semiconductor element 3. The positive-side semiconductor element 31 is connected to the output terminal 63 via a first connection conductor 71 that is one of the connection conductors 7 at an emitter that is an electrode opposite to the wiring board 2. The negative electrode side semiconductor element 32 is connected to the negative electrode terminal 62 via a second connection conductor 72, which is a connection conductor 7 different from the first connection conductor 71, in an emitter which is an electrode opposite to the wiring board 2. . The connection conductor 7 can be formed of copper in a plate shape. As shown in FIG. 3, the positive electrode side semiconductor element 31 and the first connection conductor 71 and the negative electrode side semiconductor element 32 and the second connection conductor 72 are respectively connected via the bus bar 11. Yes.

  As shown in FIG. 3, a heat transfer conductor 12 that thermally connects the connection conductor 7 and the wiring board 2 is disposed at a position that overlaps the gap 41 and the normal direction Z. The heat transfer conductor 12 is joined to the first connection conductor 71 and the heat radiation pattern 220 formed on the upper surface of the wiring board 2. The heat transfer conductor 12 is made of copper.

  As shown in FIGS. 1 and 3, the collector of the positive electrode side semiconductor element 31 is connected to the positive electrode terminal 61 via the wiring pattern 221 of the wiring board 2. The collector of the negative electrode side semiconductor element 32 is connected to the output terminal 63 via the wiring pattern 222 of the wiring substrate 2 and the first connection conductor 71.

  As shown in FIGS. 1 to 3, the components of the semiconductor module 1 such as the wiring board 2, the semiconductor element 3, and the heat sink 4 are modularized by a mold resin 13 having electrical insulation. As shown in FIG. 3, the mold resin 13 is connected to the heat sink 4. The mold resin 13 is connected to a portion outside the portion surrounded by the gap 41 of the heat radiating plate 4. The lower surface of the heat sink 4 is an exposed surface 42 exposed from the mold resin 13.

  The semiconductor module 1 is arranged such that the exposed surface 42 of the heat radiating plate 4 faces a refrigerant flow path (not shown). The refrigerant channel is configured to allow the refrigerant to flow. And it is comprised so that the refrigerant | coolant in a refrigerant | coolant flow path may directly contact the exposed surface 42 of the heat sink 4 of the semiconductor module 1. FIG. Furthermore, the refrigerant in the refrigerant flow path is also configured to enter the air gap 41 and circulate. In addition, the refrigerant circulated in the refrigerant channel can be a liquid refrigerant such as cooling water. Alternatively, the refrigerant can be a gas refrigerant such as air. In the case of air cooling, the refrigerant flow path may not be a closed space.

Next, the effect of this embodiment is demonstrated.
In the semiconductor module 1, a gap 41 is formed in the heat sink 4. The gap 41 is formed so as to surround the semiconductor element 3 when viewed from the normal direction Z of the wiring board 2. Thereby, it is possible to prevent the entire heat sink 4 from being heated due to heat received from the semiconductor element 3. That is, the heat transmitted from the semiconductor element 3 to the heat radiating plate 4 is hardly transmitted to the outside of the region surrounded by the gap 41 in the heat radiating plate 4. Therefore, it can suppress that the area | region outside the area | region enclosed by the space | gap part 41 in the heat sink 4 becomes high temperature. Therefore, it is possible to prevent the mold resin 13 connected to the region from being deteriorated by heat.

  The gap 41 is open at least on the surface opposite to the wiring board 2. Therefore, the heat transferred from the semiconductor element 3 to the heat radiating plate 4 can be radiated not only from the surface of the heat radiating plate 4 opposite to the wiring board 2 but also from the gap 41. Therefore, the heat dissipation of the semiconductor element 3 can be improved.

  Moreover, in the semiconductor module 1, it is not necessary to enlarge the heat sink 4 in particular, and the above-described effects can be obtained.

  Further, when viewed from the normal direction Z, the gap 41 is entirely formed outside the semiconductor element 3. Therefore, it is easy to ensure the volume of the region surrounded by the gap 41 in the heat sink 4. Therefore, it is easy to ensure the heat capacity of the region surrounded by the gap 41 in the heat radiating plate 4. As a result, it is easy to improve the heat dissipation of the semiconductor element 3.

  In the parallel cross section, at least a part of the gap 41 is formed in a region outside the region between the two virtual straight lines VL in the heat radiating plate 4. Therefore, the heat transferred from the semiconductor element 3 to the heat sink 4 can be further suppressed from being transferred to the outside of the region surrounded by the gap 41 in the heat sink 4. That is, the heat of the semiconductor element 3 is spread and transferred to the outer peripheral side of the semiconductor element 3 in the plane direction orthogonal to the normal direction Z as it goes downward in the heat radiating plate 4. At this time, the direction in which heat is transmitted in the heat radiating plate 4 is inclined by about 45 ° with respect to the straight line extending in the normal direction Z. Therefore, by forming at least a part of the gap 41 in the area outside the area between the two virtual lines VL in the heat radiating plate 4, heat is easily radiated from the gap 41. It is easier to prevent heat from being transmitted to the outside of the enclosed region.

  Further, the gap 41 is formed so as to penetrate the heat radiating plate 4 in the normal direction Z. Therefore, it is easy to form the gap 41 to a position close to the semiconductor element 3. Therefore, it is easy to reduce the heat transfer distance from the semiconductor element 3 to the gap 41. Therefore, it is easy to further improve the heat dissipation of the semiconductor element 3.

  In addition, a heat transfer conductor 12 that thermally connects the connection conductor 7 and the wiring board 2 is disposed at a position overlapping the gap 41 and the normal direction Z. Therefore, the heat of the connection conductor 7 can be radiated to the gap 41 via the heat transfer conductor 12. Therefore, it is easy to reduce the heat transfer distance between the connection conductor 7 and the gap 41, and it is easy to ensure the heat dissipation of the connection conductor 7.

  Further, when viewed from the normal direction Z, the gap 41 has an annular shape. Therefore, it is easier to suppress heat from being transmitted from the region surrounded by the gap 41 in the heat radiating plate 4 to the region outside the region.

  As described above, according to the present embodiment, it is possible to provide a semiconductor module that can suppress an increase in the temperature of the outer peripheral portion of the heat radiating plate without increasing the size and can improve the heat dissipation of the semiconductor element. .

(Embodiment 2)
As shown in FIGS. 5 and 6, the present embodiment is an embodiment in which the anisotropic member 8 is disposed in the gap portion 41. The anisotropic member 8 is a member having higher thermal conductivity in the normal direction Z than in the plane direction orthogonal to the normal direction Z. In the present embodiment, the anisotropic member 8 is disposed in the entire region of the gap 41. The exposed surface 42 of the heat sink 4 and the lower surface of the anisotropic member 8 are formed flush with each other. And the lower surface of the heat sink 4 and the lower surface of the anisotropic member 8 are arranged facing the cooler. The anisotropic member 8 can be, for example, graphite. In FIG. 5, the anisotropic member 8 is hatched for convenience.

Others are the same as in the first embodiment.
Of the reference numerals used in the second and subsequent embodiments, the same reference numerals as those used in the above-described embodiments represent the same components as those in the above-described embodiments unless otherwise indicated.

In the present embodiment, heat transfer in the normal direction Z can be improved while suppressing heat transfer in the surface direction orthogonal to the normal direction Z inside the gap 41. Therefore, it is easy to move the heat that has reached the gap 41 to the lower side, that is, the side where the cooler is arranged, while suppressing the movement to the outside.
In addition, the same effects as those of the first embodiment are obtained.

(Embodiment 3)
As shown in FIGS. 7 and 8, the present embodiment is an embodiment in which the semiconductor module 1 is configured to be cooled on both sides. In addition, the semiconductor module 1 of the present embodiment is a so-called 1 in 1 type semiconductor module in which one semiconductor element 3 is incorporated.

  As shown in FIG. 8, in this embodiment, the semiconductor module 1 has a pair of heat sinks 4. The pair of heat radiating plates 4 are arranged to face the normal direction Z while providing a constant interval between them.

  The wiring board 2 is arranged on the opposing surfaces of the pair of heat sinks 4. Wiring patterns 223 and 224 are respectively formed on the side of the pair of wiring boards 2 opposite to the side on which the heat dissipation plate 4 is disposed. The semiconductor element 3 is disposed between the pair of wiring patterns 223 and 224. The collector of the semiconductor element 3 is connected to the wiring pattern 223 of one wiring board 2, and the emitter of the semiconductor element 3 is connected to the wiring pattern 224 of the other wiring board 2 via the bus bar 11. A diode 14 is disposed at a position adjacent to the semiconductor element 3 in a direction orthogonal to the normal direction Z. The diode 14 is connected in antiparallel to the semiconductor element 3. The diode 14 is an FWD (that is, a flywheel diode). As shown in FIG. 7, one of the pair of wiring patterns 223 and 224 is electrically connected to the output terminal 63, and the other is electrically connected to the positive terminal 61 or the negative terminal 62.

  As shown in FIG. 8, in the present embodiment, a gap 41 is formed in each of the pair of heat sinks 4. The pair of gaps 41 formed in the pair of heat sinks 4 are formed so as to surround the semiconductor element 3 when viewed from the normal direction Z.

Also in the present embodiment, the components of the semiconductor module such as the wiring substrate 2, the semiconductor element 3, and the heat sink 4 are modularized by a mold resin having electrical insulation. A mold resin 13 is connected to each of the pair of heat sinks 4. The mold resin 13 is connected to a region on the outer peripheral side with respect to the region surrounded by the gap 41 in the surface direction orthogonal to the normal direction Z of each heat radiating plate 4. The surface of each heat radiating plate 4 opposite to the side on which the wiring board 2 is arranged is an exposed surface 42 exposed from the mold resin 13. And each of the exposed surface 42 of a pair of heat sink 4 is distribute | arranged facing the cooler which is not shown in figure. Thereby, the semiconductor module 1 of this embodiment is comprised so that double-sided cooling is possible.
Others are the same as in the first embodiment.

In the present embodiment, since the heat of the semiconductor element 3 can be radiated from both sides thereof, further improvement in heat dissipation can be achieved.
In addition, the same effects as those of the first embodiment are obtained.

(Embodiment 4)
As shown in FIG. 9, the present embodiment is an embodiment in which the shape of the gap 41 is changed with respect to the first embodiment. In the present embodiment, the gap 41 is formed such that a part of the lower end surface of the heat radiating plate 4 is recessed upward. In the present embodiment, the gap 41 opens toward the lower side, but the upper side is closed by a closing portion 43 that is a part of the heat sink 4. That is, the gap 41 does not penetrate the heat sink 4 in the normal direction Z.

Others are the same as in the first embodiment.
This embodiment also has the same effects as those of the first embodiment.

  The present invention is not limited to the above embodiments, and can be applied to various embodiments without departing from the scope of the invention.

  For example, in the first embodiment, the third embodiment, and the fourth embodiment, fins for improving the heat dissipation of the heat sink are extended from the wall surface facing the gap in the heat sink toward the inside of the gap. May be. In this case, in the said Embodiment 4, a fin can also be extended toward the downward side from the said obstruction | occlusion part, for example.

  Moreover, in each said embodiment, although the one space | gap part was formed in one heat sink, it was not restricted to this, The several space | gap part may be formed in one heat sink. . For example, in each of the above-described embodiments, the gap portion has an annular shape when viewed from the normal direction, but the annular gap portion may have a shape that is divided into a plurality of circumferential directions. .

  Moreover, in the said embodiment, although the space | gap part showed the form formed so that a semiconductor element might be enclosed from a perimeter when it sees from a normal line direction, it is not restricted to this. For example, the void portion can be formed so as to surround the semiconductor element from both sides in one direction orthogonal to the normal direction when viewed from the normal direction.

Further, the anisotropic member shown in the second embodiment may be disposed in the gap portion of the third embodiment.
In the first and second embodiments, the configuration of the present invention is applied to a 2-in-1 type semiconductor module. In the third embodiment, the configuration of the present invention is applied to a 1-in-1 type semiconductor module. Although shown, it is not restricted to this, For example, you may apply the structure of this invention to what is called a 6 in1 type semiconductor module which incorporated six semiconductor elements.

DESCRIPTION OF SYMBOLS 1 Semiconductor module 2 Wiring board 21 Insulating layer 221, 222 Wiring pattern 3 Semiconductor element 4 Heat sink 41 Gap part Z Normal direction

Claims (8)

A wiring board (2) having wiring patterns (221, 222, 223, 224) formed on an insulating layer (21);
A semiconductor element (3) mounted on the wiring board;
A heat sink (4) disposed on the surface of the wiring board opposite to the semiconductor element,
The heat sink has a gap (41) that is open at least on the surface opposite to the wiring board.
The gap is formed so as to surround the semiconductor element when viewed from the normal direction (Z) of the wiring board .
The semiconductor module (1) , in which the anisotropic member (8) having higher heat transfer in the normal direction than the surface direction orthogonal to the normal direction is arranged in the gap . The semiconductor module further includes a power terminal (6), and the semiconductor element is connected to the power terminal via a connection conductor (7) at an electrode on the opposite side of the wiring substrate in the semiconductor element. The semiconductor module according to claim 1, wherein a heat transfer conductor (12) that thermally connects the connection conductor and the wiring board is disposed at a position that overlaps the gap and the normal direction . A wiring board (2) having wiring patterns (221, 222, 223, 224) formed on an insulating layer (21);
A semiconductor element (3) mounted on the wiring board;
A heat sink (4) disposed on the surface of the wiring board opposite to the semiconductor element;
A power terminal (6),
The heat sink has a gap (41) that is open at least on the surface opposite to the wiring board.
The gap is formed so as to surround the semiconductor element when viewed from the normal direction (Z) of the wiring board.
The semiconductor element is connected to the power terminal via a connection conductor (7) at an electrode opposite to the wiring board in the semiconductor element,
A semiconductor module (1), wherein a heat transfer conductor (12) for thermally connecting the connection conductor and the wiring board is disposed at a position overlapping the gap and the normal direction . The semiconductor module according to claim 3 , wherein an anisotropic member (8) having a higher heat transfer property in the normal direction than in a plane direction orthogonal to the normal direction is arranged in the gap . The semiconductor module according to any one of claims 1 to 4, wherein the gap is entirely formed outside the semiconductor element as viewed from the normal direction . When two virtual straight lines (VL) defined below are assumed in a cross-section parallel to the normal direction passing through the semiconductor element, at least a part of the gap is defined by the two virtual straight lines in the heat sink. The two imaginary straight lines extend from both ends (33) of the heat sink side surface of the semiconductor element toward the surface side of the heat sink. And as it goes to the surface side of the heat sink, it is inclined to increase the distance between them, and the angle formed between each virtual line and the straight line (NL) extending in the normal direction is 45 °. in a semiconductor module according to any one of claims 1 to 5. The semiconductor module according to claim 1 , wherein the gap is formed so as to penetrate the heat radiating plate in the normal direction .   The semiconductor module according to any one of claims 1 to 7, wherein the gap portion has an annular shape when viewed from the normal direction.

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