Cooler, semiconductor device, and vehicle

Abstract

In the present invention, the cooling performance of a cooler applied to a semiconductor device is improved. A cooler (2) comprises: a top plate on a first surface of which a heat-dissipating surface is formed; a bottom plate that is disposed facing the top plate and that has a greater thickness than that of the top plate; a plurality of fins (210) connected to at least the top plate; and a peripheral wall part formed, between the top plate and the bottom plate, so as to surround the outer periphery of the plurality of fins. A refrigerant flow path (260) surrounded by the top plate, the bottom plate, and the peripheral wall part is formed, the refrigerant flow path having a refrigerant inflow port (251) provided toward one end in a first direction of the refrigerant flow path and a refrigerant outflow port (252) provided toward the other end thereof in the first direction. The plurality of fins each include an inclined portion that, in a first plan view when viewed from a second direction perpendicular to the first direction, extends in a direction of displacement toward the refrigerant inflow port as the distance from the first surface of the top plate increases and that, in a second plan view when viewed from the first direction, extends in a direction of displacement in the second direction as the distance from the first surface of the top plate increases.

Description

Cooler, semiconductor device, and vehicle

[0001] The present invention relates to a cooler, a semiconductor device, and a vehicle.

[0002] Some semiconductor devices used in power conversion devices such as inverters include a cooler that circulates a coolant to dissipate heat generated by semiconductor elements. This type of cooler has multiple fins in a flow path through which the coolant circulates (see, for example, Patent Documents 1 to 5).

[0003] Japanese Patent No. 3469475 JP 2018-207017 A Japanese Patent No. 5901343 Japanese Patent No. 6138197 Japanese Patent No. 3236137

[0004] In the semiconductor device described above, it is desirable to improve the cooling performance of the cooler.

[0005] The present invention has been made in view of the above points, and has as its object to improve the cooling performance of a cooler applied to a semiconductor device.

[0006] A cooler according to one aspect of the present invention includes a top plate having a heat dissipation surface formed on a first surface thereof, a bottom plate disposed opposite the top plate and thicker than the top plate, a plurality of fins connected to at least the top plate, and a peripheral wall formed between the top plate and the bottom plate so as to surround an outer periphery of the plurality of fins. A flow path of a refrigerant is formed by a space surrounded by the top plate, the bottom plate, the plurality of fins, and the peripheral wall. A heat dissipation surface is provided on the top plate, the bottom plate, or the peripheral wall at one end side in a first direction of the flow path of the refrigerant. the refrigerant inlet provided on the top plate, the bottom plate, or the peripheral wall portion at the other end side in the first direction, the refrigerant outlet provided on the top plate, the bottom plate, or the peripheral wall portion at the other end side in the first direction, and each of the plurality of fins includes an inclined portion that, in a first plan view when viewed from a second direction perpendicular to the first direction, extends in a direction displaced toward the refrigerant inlet as it moves away from the first surface of the top plate, and that, in a second plan view when viewed from the first direction, extends in a direction displaced in the second direction as it moves away from the first surface of the top plate.

[0007] According to the present invention, the cooling performance of a cooler applied to a semiconductor device can be improved.

[0008] 1 is a top view illustrating a configuration example of a semiconductor device according to an embodiment. FIG. 2 is a top view illustrating an enlarged configuration of one circuit formation portion in the semiconductor device of FIG. 1. FIG. 3 is a cross-sectional side view illustrating a configuration example of a semiconductor device taken along line A-A' in FIG. 1. FIG. 4 is a cross-sectional side view illustrating a configuration example of a semiconductor device taken along line B-B' in FIG. 1. FIG. 5 is a diagram illustrating a circuit configuration example of an inverter device to which the semiconductor device of FIG. 1 is applied. FIG. 6 is a bottom view illustrating a specific example of fins in a cooler according to an embodiment. FIG. 7 is a view illustrating a first characteristic of a refrigerant flow in a cooler according to an embodiment. FIG. 8 is a view illustrating a second characteristic of a refrigerant flow in a cooler according to an embodiment. FIG. 9 is a graph illustrating a relationship between an angle in the extension direction of the fins and thermal resistance and pressure loss. FIG. 10 is a diagram for supplementing information regarding the angle and arrangement of the extension direction of the fins. FIG. 11 is a cross-sectional side view illustrating a first modified example of the configuration of the cooler. FIG. 12 is a cross-sectional side view illustrating a first modified example of the fin arrangement. FIG. 13 is a cross-sectional side view illustrating a second modified example of the fin arrangement. FIG. 14 is a cross-sectional side view illustrating a third modified example of the fin arrangement. FIG. 15 is a cross-sectional side view illustrating a second modified example of the cooler configuration. FIG. 1 is a cross-sectional side view showing a fourth modified example of the cooler configuration. FIG. 2 is a view explaining a fifth modified example of the cooler configuration. FIG. 3 is a view explaining a sixth modified example of the cooler configuration. FIG. 4 is a bottom view explaining a modified example of the positional relationship between the refrigerant inlet and outlet in the cooler. FIG. 5 is a cross-sectional side view showing a first modified example of the cooler configuration and the positional relationship between the refrigerant inlet and outlet. FIG. 6 is a cross-sectional side view showing a second modified example of the cooler configuration and the positional relationship between the refrigerant inlet and outlet. FIG. 7 is a cross-sectional side view showing a third modified example of the cooler configuration and the positional relationship between the refrigerant inlet and outlet. FIG. 8 is a schematic plan view showing an example of a vehicle to which the semiconductor device according to the present invention is applied.

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The X-axis, Y-axis, and Z-axis in each of the referenced figures are shown for the purpose of defining planes and directions in the illustrated semiconductor device, cooler, etc. The X-axis, Y-axis, and Z-axis are orthogonal to one another and form a right-handed system. In the following description, the direction parallel to the X-axis will be referred to as the X-direction, the direction parallel to the Y-axis will be referred to as the Y-direction, and the direction parallel to the Z-axis will be referred to as the Z-direction. Furthermore, when the X-direction, Y-direction, and Z-direction are associated with the directions of the arrows (positive and negative) of the X-axis, Y-axis, and Z-axis shown in the drawings, they will be referred to as the "positive side" or "negative side."

[0010] In this specification, the Z direction may be referred to as the up-down direction. In this specification, "up" and "above" refer to the positive side of the Z direction relative to a reference surface, component, position, etc., and "down" and "below" refer to the negative side of the Z direction relative to a reference surface, component, position, etc. For example, when describing "component B is placed on component A," component B is placed on the positive side of the Z direction relative to component A. Furthermore, when describing "the top surface of component A," this surface is the surface located at the end of component A on the positive side of the Z direction, facing the positive side of the Z direction. In this specification, "top view" refers to a planar view of a target object (e.g., a semiconductor device, a cooler, etc.) viewed from the positive side of the Z direction, and "bottom view" refers to a planar view of a target object viewed from the negative side of the Z direction. In this specification, "front view" refers to a planar view of a target object viewed from the negative side of the Y direction. In this specification, the term "side view" refers to a planar view of the object as viewed from the negative side or the positive side in the X direction. A planar view from the negative side in the X direction is sometimes referred to as a "left side view," and a planar view from the positive side in the X direction is sometimes referred to as a "right side view." These directions and surfaces are used for convenience of explanation, and their correspondence with the X-axis, Y-axis, and Z-axis may change depending on the mounting orientation of the semiconductor device. For example, the surface of a cooler on which the wiring board and semiconductor elements are arranged is referred to as the top surface of the cooler in this specification, but may also be referred to as the bottom surface, side surface, etc. of the cooler. Furthermore, the aspect ratios and the size relationships between the components in each figure are merely schematic representations and do not necessarily correspond to the relationships in an actually manufactured semiconductor device, cooler, etc. For convenience of explanation, the size relationships between the components may be exaggerated.

[0011] Furthermore, the semiconductor device exemplified in the following description may be applied to a power conversion device such as an inverter device for industrial or electrical equipment (e.g., an in-vehicle motor), etc. Therefore, in the following description, detailed descriptions of configurations, functions, operations, manufacturing methods, etc. that are the same as or similar to those of known semiconductor devices will be omitted.

[0012] FIG. 1 is a top view showing an example of the configuration of a semiconductor device according to one embodiment. FIG. 2 is an enlarged top view of the configuration of one circuit formation portion in the semiconductor device of FIG. 1. FIG. 3 is a cross-sectional side view showing an example of the configuration of a semiconductor device taken along line A-A' in FIG. 1. FIG. 4 is a cross-sectional side view showing an example of the configuration of a semiconductor device taken along line B-B' in FIG. 1. The cross-sectional side view of FIG. 3 shows a right side view of a portion of the semiconductor device taken along line A-A' in FIG. 1, the portion being to the left of line A-A'. The cross-sectional side view of FIG. 4 shows a front view of a portion of the semiconductor device taken along line B-B' in FIG. 1, the portion being above line B-B'. Note that FIGS. 2 and 3 omit illustration of an encapsulant that encapsulates a semiconductor element, etc., and FIG. 4 omits illustration of leads, a case, an encapsulant, etc.

[0013] The semiconductor device 1 illustrated in FIGS. 1 to 4 includes a cooler 2, a wiring board 3, semiconductor elements 4A and 4B, a case 5, wiring components 6A to 6F, and a sealing material .

[0014] The cooler 2 has a coolant flow path 260 formed therein for dissipating heat generated by the semiconductor elements 4A and 4B of the semiconductor device 1, and is connected to a circulation circuit for circulating the coolant. The coolant flow path 260 in the cooler 2 is defined by a top plate 200, a bottom plate 230, and a peripheral wall portion 240. The top plate 200 has a roughly rectangular outer shape when viewed from above, and a plurality of fins 210 extending downward from the lower surface (heat dissipation surface) 202 are disposed on the lower surface 202. The peripheral wall portion 240 has a quadrangular ring shape when viewed from above that surrounds the outer periphery of the plurality of fins 210, and is disposed below the top plate 200 so that the upper open end is covered by the top plate 200. The bottom plate 230 is disposed below the peripheral wall portion 240 so as to cover the lower open end of the peripheral wall portion 240. In the cooler 2, the relationship between the thickness T1 of the top plate 200 and the thickness T2 of the bottom plate 230 disposed opposite the top plate 200 may be T2>T1, as illustrated in Figures 3 and 4. Furthermore, the thickness T3 of the peripheral wall portion 240 may be T3>T2.

[0015] The top plate 200, peripheral wall portion 240, and bottom plate 230 illustrated in Figures 3 and 4 are integrated such that the upper surface of the peripheral wall portion 240 is in close contact with the lower surface 202 of the top plate 200, and the lower surface of the peripheral wall portion 240 is in close contact with the upper surface 231 of the bottom plate 230. The method for integrating the top plate 200, peripheral wall portion 240, and bottom plate 230 is not limited to a specific method. In addition, in the cooler 2 illustrated in Figures 3 and 4, the peripheral wall portion 240 has an inlet 251 through which the refrigerant flows into the refrigerant flow path 260, and an outlet 252 through which the refrigerant is discharged from the refrigerant flow path 260. The outlet 252 may also be referred to as an outlet through which the refrigerant flows out. A specific description of the configuration of the cooler 2 will be given later.

[0016] 1 has three wiring boards 3 arranged on a top plate 200 of a cooler 2. The three wiring boards 3 have substantially the same configuration and include an insulating substrate 300, conductor patterns 301 to 303 provided on the upper surface of the insulating substrate 300, and a conductor pattern 304 provided on the lower surface of the insulating substrate 300. The wiring board 3 may be, for example, a DCB (Direct Copper Bonding) substrate or an AMB (Active Metal Brazing) substrate. The wiring board 3 may also be called a laminated substrate, an insulating circuit board, or the like.

[0017] The insulating substrate 300 is not limited to a specific substrate. The insulating substrate 300 may be, for example, aluminum oxide (Al ２ O ３ ), aluminum nitride (AlN), silicon nitride (Si ３ N ４ ), or aluminum oxide (Al ２ O ３ ) and zirconium oxide (ZrO ２ The insulating substrate 300 may be, for example, a substrate formed from an insulating resin such as an epoxy resin, a substrate in which a base material such as glass fiber is impregnated with an insulating resin, or a substrate in which the surface of a flat metal core is coated with an insulating resin.

[0018] The conductor pattern 304 provided on the lower surface of the insulating substrate 300 functions as a heat-conducting member that conducts heat generated by the semiconductor elements 4A and 4B to the cooler 2, and is formed of, for example, a metal plate or metal foil such as copper or aluminum. The conductor pattern 304 is joined to the upper surface 204 of the top plate 200 of the cooler 2 by a joining material (not shown) such as solder. The conductor pattern 304 may also be called a heat dissipation layer or a heat dissipation pattern. The wiring board 3 may be arranged, for example, by joining the conductor pattern 304 to a base plate separate from the top plate 200, so that heat is conducted to the top plate 200 via the base plate.

[0019] The conductor patterns 301 to 303 provided on the upper surface of the insulating substrate 300 function as wiring components and are formed, for example, from a metal plate or metal foil such as copper or aluminum. The conductor patterns 301 to 303 provided on the upper surface of the insulating substrate 300 may also be called conductor layers, conductor plates, conductive layers, wiring patterns, etc. In the following description, when distinguishing between the conductor patterns 301 to 303, they will be referred to as the first conductor pattern 301, the second conductor pattern 302, and the third conductor pattern 303, respectively.

[0020] A semiconductor element 4A is disposed on the upper surface of the first conductor pattern 301. The first conductor pattern 301 is bonded to a first main electrode (not shown) provided on the lower surface of the semiconductor element 4A with a bonding material (not shown). The bonding material is a well-known bonding material such as solder. A semiconductor element 4B is disposed on the upper surface of the second conductor pattern 302. The second conductor pattern 302 is bonded to a first main electrode (not shown) provided on the lower surface of the semiconductor element 4B with a bonding material (not shown).

[0021] Each of the semiconductor elements 4A and 4B is configured, for example, as an RC (Reverse Conducting)-IGBT element that integrates the functions of an IGBT (Insulated Gate Bipolar Transistor) element, which is a switching element, and a diode element such as an FWD (Free Wheeling Diode) element connected in antiparallel to the switching element. Each of these semiconductor elements 4A and 4B has a first main electrode on its bottom surface and a second main electrode and a control electrode (gate electrode) on its top surface. When the switching elements of the semiconductor elements 4A and 4B are IGBT elements, the first main electrode on the bottom surface may be called a collector electrode, and the second main electrode on the top surface may be called an emitter electrode.

[0022] The first main electrode provided on the underside of the semiconductor element 4A is electrically connected to a first main terminal 501 provided on the case 5 via a first conductor pattern 301. The first conductor pattern 301 and the first main terminal 501 are electrically connected by a well-known method. For example, the first conductor pattern 301 and the first main terminal 501 are electrically connected via a columnar or block-shaped wiring component (not shown) extending upward from the upper surface of the first conductor pattern 301. The second main electrode 401 provided on the upper surface of the semiconductor element 4A is electrically connected to a third main terminal 503 provided on the case 5 via a wiring component 6A and a second conductor pattern 302. The wiring component 6A is formed by bending a conductor plate such as a copper plate and is also called a lead, lead frame, etc. The wiring component 6A is joined to the second main electrode 401 and the second conductor pattern 302 of the semiconductor element 4A by a bonding material (not shown). 2, the second conductor pattern 302 and the third main terminal 503 are electrically connected via a columnar conductive member (wiring component 6B) extending upward from the upper surface of the second conductor pattern 302. The second conductor pattern 302 and the third main terminal 503 may be electrically connected by another well-known method. The control electrode 402 provided on the upper surface of the semiconductor element 4A is electrically connected to a control terminal 504 provided on the case 5 by a bonding wire (wiring component 6E).

[0023] The first main electrode provided on the lower surface of the semiconductor element 4B is electrically connected to a third main terminal 503 provided on the case 5 via the second conductor pattern 302 and the wiring component 6B. The second main electrode 401 provided on the upper surface of the semiconductor element 4B is electrically connected to a second main terminal 502 provided on the case 5 via the wiring component 6C and the third conductor pattern 303. The wiring component 6C is formed by bending a conductor plate such as a copper plate, and is also called a lead, lead frame, or the like. The wiring component 6C is joined to the second main electrode 401 and the third conductor pattern 303 of the semiconductor element 4B by a bonding material (not shown). In the example of FIG. 2 , the third conductor pattern 303 and the second main terminal 502 are electrically connected via a columnar conductive member (wiring component 6D) extending upward from the upper surface of the third conductor pattern 303. A control electrode 402 provided on the upper surface of the semiconductor element 4B is electrically connected to a control terminal 505 provided on the case 5 by a bonding wire (wiring component 6F).

[0024] The case 5 includes an insulating member 500 having an open upper and lower ends and a hollow portion 510 capable of accommodating the wiring board 3, semiconductor elements 4A and 4B, and wiring components 6A to 6F, etc., and the above-described first main terminal 501, second main terminal 502, third main terminal 503, control terminal 504, and control terminal 505. One end of each of the first main terminal 501, second main terminal 502, third main terminal 503, control terminal 504, and control terminal 505 is exposed within the hollow portion 510 of the insulating member 500, and the other end protrudes from the upper surface of the insulating member 500. The portions of the first main terminal 501, second main terminal 502, and third main terminal 503 protruding from the upper surface of the insulating member 500 are bent so as to fit along the upper surface of the insulating member 500. Recesses into which nuts 9 are fitted are formed in regions on the top surface of the insulating member 500 that overlap with the first main terminal 501, the second main terminal 502, and the third main terminal 503. The first main terminal 501, the second main terminal 502, and the third main terminal 503 are formed with through holes 521, 522, and 523, respectively, that correspond to the screw holes of the nuts 9 that are fitted in the recesses formed in the top surface of the insulating member 500. The nuts 9 are used to screw in bolts that connect the first main terminal 501, the second main terminal 502, and the third main terminal 503 to, for example, terminals of power supply cables such as wire harnesses or power supply components such as bus bars.

[0025] Hollow portion 510 of case 5 is filled with sealing material 7 that seals wiring board 3, semiconductor elements 4A and 4B, wiring components 6A to 6F, etc. Sealant 7 is, for example, epoxy resin or silicone gel. Hollow portion 510 of case 5 may be formed as a single hollow portion without being divided into sections for each wiring board 3 (i.e., without being divided into three separate hollow portions) as illustrated in FIG.

[0026] 2, the case 5 has through holes 511 formed at positions that are corners when viewed from above. The case 5 is attached to the top plate 200 of the cooler 2, for example, by threading bolts 8 inserted into the through holes 511 into screw holes formed in the top plate 200 of the cooler 2. The positions and number of through holes 511 for attaching the case 5 to the top plate 200 are not limited to those exemplified in FIG. 2. Furthermore, the method for attaching the case 5 to the top plate 200 is not limited to a specific method.

[0027] The semiconductor device 1 illustrated in FIG. 1 includes three single-phase inverter circuits, and can constitute, for example, a three-phase inverter device.

[0028] FIG. 5 is a diagram showing an example of a circuit configuration of an inverter device to which the semiconductor device of FIG. 1 is applied.

[0029] FIG. 5 shows an example of the circuit configuration of a voltage-type three-phase inverter device as an example of the inverter device 11. The inverter device 11 includes three single-phase inverter circuits 1101(U), 1101(V), and 1101(W), a smoothing capacitor 1102, and a control circuit 1103. Each single-phase inverter circuit includes one wiring board 3 and two semiconductor elements 4A and 4B. The single-phase inverter circuit 1101(U) converts DC to AC and outputs it as U-phase AC. The single-phase inverter circuit 1101(V) converts DC to AC and outputs it as V-phase AC. The single-phase inverter circuit 1101(W) converts DC to AC and outputs it as W-phase AC. In this specification, the three phases of the three-phase AC are referred to as the U-phase, V-phase, and W-phase, but may be referred to by other names.

[0030] Inverter device 11 has three single-phase inverter circuits 1101(U), 1101(V), and 1101(W) connected in parallel with a smoothing capacitor 1102. The circuit configuration of each of the three single-phase inverter circuits 1101(U), 1101(V), and 1101(W), illustrated by the equivalent circuit in Fig. 5, corresponds to the circuit formed by one wiring board 3 and two semiconductor elements 4A and 4B in semiconductor device 1 described above with reference to Figs.

[0031] The inverter device 11 has a first input terminal IN(P) to which the positive electrode of the DC power supply 12 is connected, a second input terminal IN(N) to which the negative electrode of the DC power supply 12 is connected, and output terminals OUT(U), OUT(V), and OUT(W) that output three-phase AC.

[0032] Each of the single-phase inverter circuits 1101(U), 1101(V), and 1101(W) illustrated in Fig. 5 is a half-bridge inverter circuit. In the single-phase inverter circuit 1101(U), a collector electrode of a switching element 410 (e.g., an IGBT element) in a semiconductor element 4A connected between a first input terminal IN(P) and an output terminal OUT(U), which may be referred to as an upper arm, is connected to the first input terminal IN(P) via a first main terminal 501. In addition, in the single-phase inverter circuit 1101(U), a collector electrode of a switching element 412 in a semiconductor element 4B connected between a second input terminal IN(N) and an output terminal OUT(U), which may be referred to as a lower arm, is connected to the second input terminal IN(N) via a second main terminal 502. The emitter electrode of the upper-arm switching element 410 and the collector electrode of the lower-arm switching element 412 in the single-phase inverter circuit 1101(U) are connected to an output terminal OUT(U) that outputs U-phase AC in the three-phase AC via a third main terminal 503. A diode element 411 is connected in anti-parallel to the upper-arm switching element 410, and a diode element 413 is connected in anti-parallel to the lower-arm switching element 412. The other two single-phase inverter circuits 1101(V) and 1101(V) have a configuration in which the output terminal OUT(U) in the above-mentioned single-phase inverter circuit 1101(U) is replaced with output terminals OUT(V) and OUT(V), respectively.

[0033] The AC outputs from the single-phase inverter circuits 1101(U), 1101(V), and 1101(W) are controlled so that the phases are shifted by 120 degrees from each other by a control signal applied from a control circuit 1103 to the gate of the upper arm switching element 410 (control electrode 402 of semiconductor element 4A) via a control terminal 504 and a control signal applied to the gate of the lower arm switching element 412 (control electrode 402 of semiconductor element 4B) via a control terminal 505. A load (e.g., an AC motor) 13 that operates on AC is connected to output terminals OUT(U), OUT(V), and OUT(W) of the inverter device 11.

[0034] The circuit configuration of the inverter device 11 including the semiconductor device 1 of this embodiment is not limited to the circuit configuration exemplified in Fig. 5. Furthermore, the operation of the inverter device 11 including the semiconductor device 1 of this embodiment is not limited to a specific operation. For example, the inverter device 11 including the semiconductor device 1 may be configured by connecting three single-phase full-bridge inverter circuits in parallel.

[0035] Furthermore, the inverter device 11 described above with reference to FIG. 5 is merely an example of a device to which the semiconductor device 1 according to this embodiment is applied.

[0036] The switching elements 410 and 412 of the semiconductor elements 4A and 4B are not limited to the IGBT elements described above, and may be, for example, power MOSFETs (Metal Oxide Semiconductor Field Effect Transistors), BJTs (Bipolar Junction Transistors), or the like. When the switching elements are MOSFETs, the main electrodes on the lower surfaces of the semiconductor elements 4A and 4B may be called drain electrodes, and the main electrodes on the upper surfaces may be called source electrodes. Furthermore, the diode elements 411 and 413 may be, for example, Schottky Barrier Diodes (SBDs), Junction Barrier Schottky (JBS) diodes, Merged PN Schottky (MPS) diodes, PN diodes, or the like. Furthermore, the control electrode 402 provided on the upper surfaces of the semiconductor elements 4A and 4B may include a gate electrode and an auxiliary electrode. For example, the auxiliary electrode may be an auxiliary emitter electrode or auxiliary source electrode electrically connected to the upper main electrode and serving as a reference potential for the gate potential. The auxiliary electrode may also be a temperature sensing electrode electrically connected to a temperature sensing unit that may be included in the inverter device 11, etc., and measuring the temperature of the semiconductor elements 4A and 4B. These electrodes (the second main electrode 401 and the control electrode 402 including the gate electrode and auxiliary electrode) formed on the upper surfaces of the semiconductor elements 4A and 4B may collectively be referred to as upper electrodes. Furthermore, the substrates on which the switching elements 410 and 412 and the diode elements 411 and 413 are formed are not limited to silicon substrates, and may be, for example, silicon carbide (SiC) substrates, gallium nitride (GaN) substrates, etc.

[0037] Furthermore, the switching element and the diode element described as being included in one semiconductor element in the single-phase inverter circuit described above with reference to FIG. 5 may be provided by separate semiconductor elements. For example, the upper arm switching element 410 and the diode element 411 may be provided by a semiconductor element on which the switching element 410 is formed and a semiconductor element on which the diode element 411 is formed. The shape, number, and location of the semiconductor elements may be changed as appropriate. The layout of the conductor patterns serving as wiring components provided on the upper surface of the wiring board 3 may be changed depending on the type, shape, number, and location of the semiconductor elements.

[0038] The cooler 2 in the semiconductor device 1 according to this embodiment may include, for example, a top plate 200 having a plurality of fins 210 arranged on a lower surface 202, a bottom plate 230, and a peripheral wall portion 240, as described above with reference to FIGS. 3 and 4 . The cooler 2 illustrated in this embodiment has a refrigerant inlet 251 on its left side and a refrigerant outlet 252 on its right side when viewed from above ( FIG. 1 ) and from the front ( FIG. 4 ). In other words, the refrigerant flow path 260 of the cooler 2, defined by the top plate 200, the bottom plate 230, and the peripheral wall portion 240, has its upstream end on the left side and its downstream end on the right side. The number of single-phase inverter circuits (combinations of a wiring board 3 and semiconductor elements 4A and 4B) arranged on the top plate 200 of one cooler 2 is not limited to three. Furthermore, the top plate 200 may also include the single-phase inverter circuit and a circuit other than the single-phase inverter circuit.

[0039] As will be described later with reference to Fig. 6 , each of the multiple fins 210 is a fin having a columnar outer shape, sometimes called a pin fin, and is arranged in a two-dimensional lattice pattern on the underside 202 of the top plate 200. The top plate 200 on which the multiple fins 210 are arranged is a member that dissipates heat conducted from the semiconductor elements 4A and 4B via the wiring board 3, and is made of, for example, an aluminum alloy. The extension direction of the fins 210 in the cooler 2 of this embodiment is non-parallel to the normal direction (Z direction) of the underside 202 in both the front view (Fig. 4) and the side view (Fig. 3). More specifically, each of the multiple fins 210 extends so that it is displaced toward the upstream side of the refrigerant flow path 260 as it moves away from the underside 202 of the top plate 200 in a front view ( FIG. 4 ), and displaced toward the horizontal end face of the refrigerant flow path 260 as it moves away from the underside 202 of the top plate 200 in a side view ( FIG. 3 ) (in other words, the distance from the peripheral wall portion 240 changes). Angle θ1 on the acute side of the extension direction of the fin 210 in a front view (hereinafter simply referred to as “angle θ1”) and angle θ2 on the acute side of the extension direction of the fin 210 in a side view (hereinafter simply referred to as “angle θ2”) may be the same value or different values.

[0040] FIG. 6 is a bottom view illustrating a specific example of fins in a cooler according to an embodiment.

[0041] 6, each of the multiple fins 210 in the cooler 2 according to this embodiment has an outer shape of an inclined column, and is arranged in a two-dimensional lattice pattern with a spacing D1 between adjacent fins 210 in a direction at 45 degrees relative to the extension directions (X direction and Y direction) of the sides on the underside 202 of the top plate 200. In this specification, the term "inclined columnar" refers to a columnar shape in which the center P1 of the end face (first bottom face) on the underside 202 side of the top plate 200 in the extension direction of the fin 210 and the center P2 of the end face (second bottom face) furthest from the underside 202 do not coincide in a plan view (viewed from below).

[0042] 6 has a square first bottom surface (and second bottom surface), and is arranged such that the extension direction of the sides on the first bottom surface is at 45 degrees relative to the extension direction of the sides on the lower surface 202 of the top plate 200. In other words, the fins 210 are arranged such that the extension direction of the sides on the first bottom surface is at 45 degrees relative to the direction (X-axis direction) from the refrigerant inlet 251 (upstream) to the refrigerant outlet 252 (downstream).

[0043] The top plate 200 having a plurality of fins 210, each of which has an inclined columnar shape, arranged in a two-dimensional lattice pattern, as illustrated in FIG. 6 , can be manufactured using a known method. For example, the top plate 200 having a plurality of fins 210, each of which has an inclined columnar shape, can be manufactured by simultaneously using multiple blades to cut the surface of a metal material. Furthermore, the top plate 200 having a plurality of fins 210, each of which has an inclined columnar shape, can be manufactured using a molding method known as metal injection molding (MIM). Furthermore, the top plate 200 having a plurality of fins 210, each of which has an inclined columnar shape, can be manufactured using, for example, a 3D printer. The manufacturing method for the top plate 200 having a plurality of fins 210, each of which has an inclined columnar shape, is not limited to the manufacturing method described above.

[0044] The effects of applying the cooler 2 according to this embodiment will be described with reference to FIGS.

[0045] Fig. 7 is a diagram illustrating a first characteristic of the refrigerant flow in a cooler according to an embodiment. Fig. 8 is a diagram illustrating a second characteristic of the refrigerant flow in a cooler according to an embodiment. Fig. 9 is a graph illustrating the relationship between the angle of the fin extension direction and the thermal resistance value and pressure loss. Fig. 10 is a diagram providing additional information regarding the angle of the fin extension direction and the arrangement.

[0046] In the cooler 2 according to this embodiment, as shown in FIG. 7 , each of the fins 210 extending downward from the underside 202 of the top plate 200 has an inclined columnar shape, with the fins being displaced more upstream along the coolant flow path 260 as they move further from the top plate 200. When the semiconductor device 1 according to this embodiment is operated, a portion of the heat generated by the semiconductor elements 4A and 4B arranged on the top plate 200 is conducted to the top plate 200 of the cooler 2 via the wiring board 3 and dissipated through heat exchange between the fins 210 and the coolant flowing through the flow path 260. Because heat exchange between the fins 210 and the coolant is more active near the heat source (heat-generating element), the temperature of the upper portion of the coolant flowing through the flow path 260 defined within the cooler 2, which is closer to the semiconductor elements 4A and 4B (heat-generating element), tends to be higher than the temperature of the lower portion. When the temperature of the coolant in the upper portion of the flow path 260 becomes higher, the efficiency of heat exchange between the fins 210 and the coolant decreases, resulting in reduced cooling performance.

[0047] In contrast, as described above, each of the multiple fins 210 in the cooler 2 according to this embodiment has an inclined columnar outer shape that is displaced more upstream as the portion is farther from the top plate 200. In other words, each of the multiple fins 210 has an inclined side surface that is displaced more downstream as the portion is closer to the underside 202 of the top plate 200. Therefore, as illustrated in FIG. 7 , a portion of the refrigerant flowing from upstream to downstream through the flow path 260 of the cooler 2 is guided to the upper side of the flow path 260 along the inclined side surface of the fin 210. Furthermore, as illustrated in FIG. 3 , each of the multiple fins 210 in the cooler 2 according to this embodiment has an inclined columnar outer shape in which the extension direction of the fin 210 is inclined in a direction that is not parallel to the normal direction of the underside 202 of the top plate 200 even when viewed from the side. Therefore, the refrigerant flowing from upstream to downstream in the flow path 260 of the cooler 2 near both horizontal ends (the left and right ends of the flow path 260 in FIG. 3 ) in a side view can be guided along the inclined side surfaces of the fins 210 to the horizontal center. This allows the relatively low-temperature refrigerant flowing through the lower portion of the flow path 260 and the ends, where heat is less likely to be conducted from the wiring board 3, to be mixed with the relatively high-temperature refrigerant in the upper portion of the flow path 260, thereby suppressing an increase in the temperature of the refrigerant in the upper portion of the flow path 260. This effectively suppresses a decrease in the efficiency of heat exchange between the fins 210 and the refrigerant in the upper portion of the flow path 260, thereby improving cooling performance. Furthermore, the improved cooling performance allows the contact area (dimension L1) between the wiring board 3 and the top plate 20 for conducting a predetermined amount of heat from the wiring board 3 to the cooler 2 to be reduced, thereby enabling the miniaturization of the wiring board 3 and the semiconductor device 1.

[0048] 8 , when the first bottom surface of the fin 210 is square and the extension direction of the sides of the first bottom surface is inclined 45 degrees relative to the upstream-to-downstream direction of the refrigerant flow path, the refrigerant flowing from upstream to downstream repeatedly branches and merges along the inclined side surface of the fin 210, for example, as indicated by the arrows in FIG. 8 . Such branching and merging of the refrigerant in a plan view (bottom view) and the refrigerant agitation described above with reference to FIG. 7 occur in the refrigerant flowing through the flow path 260 of the cooler 2, thereby reducing refrigerant stagnation along the surface of the side surface of the fin 210 facing downstream, for example, and allowing the refrigerant whose temperature has increased due to heat exchange to be smoothly guided to the downstream outlet 252. That is, the cooler 2 according to this embodiment can also reduce pressure loss by suppressing refrigerant stagnation.

[0049] An example of the cooling performance and pressure loss effect of the cooler 2 according to this embodiment is shown in the graph of Fig. 9. The horizontal axis in the graph of Fig. 9 represents the angle θ1 (unit: degrees) of the extension direction of the fin 210 in the ZX plane (front view). In the graph of Fig. 9, the left vertical axis represents the thermal resistance value (arbitrary unit) associated with the cooling performance, and the right vertical axis represents the pressure loss (arbitrary unit).

[0050] The graph in Fig. 9 shows, as a conventional example, the thermal resistance value and pressure loss when the angle θ1 of the extension direction of the fins 210 is set to 90 degrees. The thermal resistance value and pressure loss when the angle θ1 in the graph in Fig. 9 is set to 85 degrees, 75 degrees, and 60 degrees are examples of measured values ​​when the arrangement spacing S, gap G, and height H of the fins 210 (see Fig. 10) are set to the same as the arrangement spacing S, gap G, and height H of the fins when the angle θ1 is set to 90 degrees, and only the angle θ1 is changed.

[0051] As can be seen from the graph in FIG. 9 , by setting the angle θ1 of the extension direction of the fins 210 relative to the upstream direction (−X direction) of the flow path 260 in a front view to less than 90 degrees, thermal resistance and pressure loss are reduced compared to the conventional example. Also, although not shown in the graph in FIG. 9 , setting the angle θ1 to less than 45 degrees increases the inclination of the extension direction of the fins 210 relative to the refrigerant flow path 260, thereby weakening the effectiveness of, for example, directing refrigerant from the lower portion of the flow path 260 to the upper portion. Furthermore, setting the angle θ1 to less than 45 degrees increases the amount of deviation of the center P2 of the second bottom surface from the center P1 of the first bottom surface, as described above with reference to FIG. 6 . For example, if the number of fins 210 remains the same compared to the conventional example, the flow path 260 to accommodate the fins 210 becomes larger (i.e., the cooler 2 becomes larger). On the other hand, if the dimensions of the flow path 260 remain the same compared to the conventional example, the reduced number of fins 210 reduces heat exchange efficiency. Therefore, it is preferable that the angle θ1 of the extension direction of the fin 210 relative to the upstream direction of the flow path 260 when viewed from the front be 45 degrees or more and less than 90 degrees. In particular, it can be inferred from the graph in Fig. 9 that it is more preferable that the angle θ1 be 60 degrees or more and 75 degrees or less.

[0052] 10 , when the arrangement spacing S and the dimensions of the bottom surfaces of the fins 210 (solid lines) with an angle θ1 of less than 90 degrees are the same as those of the conventional fins (dash-dot line) with an angle θ1 of 90 degrees, the gap GT in the direction perpendicular to the side surfaces of the fins 210 with an angle θ1 of less than 90 degrees is shorter than the gap G in the direction parallel to the undersurface 202 of the top plate 200 (T>GT). Therefore, by setting the angle θ1 to less than 90 degrees under the same conditions as those of the conventional example with an angle θ1 of 90 degrees and the arrangement spacing S and the dimensions of the bottom surfaces of the fins 210, the flow rate of the refrigerant flowing from the lower portion to the upper portion of the flow path 260 increases, and the refrigerant in the lower portion and the upper portion can be effectively mixed.

[0053] Furthermore, when the height H and bottom dimensions of a fin 210 with an angle θ1 of less than 90 degrees are the same as those of a conventional fin with an angle θ1 of 90 degrees, the side area is larger when the angle θ1 is less than 90 degrees. Therefore, by setting the angle θ1 to less than 90 degrees while maintaining the same height H and bottom dimensions of the fin 210 as those of a conventional fin with an angle θ1 of 90 degrees, the heat exchange efficiency of a single fin 210 can be improved. Therefore, for example, the cooling performance is improved when the arrangement spacing (number) of the fins 210 is the same as that of a conventional fin with an angle θ1 of 90 degrees. On the other hand, since the number of fins 210 required to achieve the same level of cooling performance as that of a conventional fin with an angle θ1 of 90 degrees can be reduced, for example, manufacturing a top plate 200 with multiple fins 210 arranged thereon becomes easier. Furthermore, when manufacturing a top plate 200 having multiple fins 210 arranged thereon using the above-mentioned metal powder injection molding method or a 3D printer, the number of fins 210 is reduced, which, for example, reduces the amount of material required to manufacture the top plate 200, which is advantageous in reducing manufacturing costs.

[0054] The shape of the fins 210 in the cooler 2 according to the above-described embodiment is not limited to the inclined columnar shape in which the first and second bottom surfaces are square, as described with reference to FIGS. 6 and 8 , but may be other shapes. For example, the first and second bottom surfaces of the fins 210 may be rhombic, other polygonal, circular, or oval (elliptical). Furthermore, the fins 210 may have different shapes for the first and second bottom surfaces, such as a circular first bottom surface and a square second bottom surface. The fins 210 may have different shapes for the first and second bottom surfaces, such as a circular first bottom surface and a square second bottom surface. The fins 210 may have the same shape but different orientations or dimensions. Specifically, the fin 210 may have, for example, a square first bottom surface and a square second bottom surface, and an outer shape that becomes thicker or thinner as it gets farther away from the lower surface 202 of the top plate 200, or may have an outer shape that is twisted about an axis passing through the center P1 of the first bottom surface and the center P2 of the second bottom surface. Furthermore, the fin 210 may have, for example, a portion that extends in the normal direction of the lower surface 202 between the lower surface 202 of the top plate 200 and the portion having the above-mentioned inclined columnar outer shape (inclined portion).

[0055] FIG. 11 is a cross-sectional side view illustrating a first modified example of the cooler configuration. FIG. 11 shows a right side view of the portion of the semiconductor device 1 cut along line A-A' in FIG. 1 , the portion being to the left of line A-A'. In the cooler 2 of the semiconductor device 1 illustrated in FIG. 11 , suppression members 271 and 272 are disposed in corners of a refrigerant flow path 260 defined by a top plate 200, a bottom plate 230, and a peripheral wall portion 240, where fins 210 are unlikely to stir the refrigerant in a side view. These suppression members 271 and 272 suppress the flow of refrigerant from upstream to downstream and promote refrigerant stirring. The left end face of the refrigerant flow path 260 illustrated in FIG. 11 increases in distance to the side face of the fin 210 as it moves downward. Without suppression member 271, refrigerant that moves along the left end face toward the lower end would be less likely to return to the horizontal center. 11 , the distance to the side surface of the fin 210 decreases as the right end surface of the refrigerant flow path 260 moves downward. If the suppression member 272 is not provided, the refrigerant flowing along the upper right corner of the flow path 260 is less likely to move downward. In this way, if there is a portion of the refrigerant flow path 260 where refrigerant agitation is difficult depending on the extension direction and arrangement of the fin 210 in a side view, the suppression members 271 and 272 can be provided to promote refrigerant agitation. For example, the suppression member 271 provided at the lower left corner of the refrigerant flow path 260 shown in FIG. 11 provides an inclined surface that moves downward toward the horizontal center, thereby directing the refrigerant that moves toward the lower end along the left side toward the horizontal center. In addition, the suppression member 272 arranged in the upper right corner of the refrigerant flow path 260 illustrated in Figure 11 provides an inclined surface that meets the underside 202 of the top plate 200 at an obtuse angle, thereby suppressing the refrigerant moving along the underside 202 toward the right end surface from accumulating in the upper right corner and enabling the refrigerant to be guided toward the lower end of the flow path.

[0056] The angles θ3 and θ4 of the inclined surfaces of the suppression members 271 and 272 arranged in the refrigerant flow path 260 in a side view are not limited to any particular angle. The angles θ3 and θ4 of the inclined surfaces of the suppression members 271 and 272 may be different from the angle θ2 of the extension direction of the fins 210, as illustrated in FIG. 11 . The cross-sectional shape of the suppression members 271 and 272 in a side view is not limited to the triangular shape illustrated in FIG. 11 . Furthermore, other suppression members than the suppression members 271 and 272 illustrated in FIG. 11 may be arranged in the refrigerant flow path 260. Instead of providing the suppression members 271 and 272, for example, any of the top plate 200, the bottom plate 230, and the peripheral wall portion 240 that define the refrigerant flow path 260 may have an inclined surface that corresponds to the inclined surface provided by the suppression members 271 and 272.

[0057] Fig. 12 is a cross-sectional side view illustrating a first modified example of the fin arrangement. Fig. 13 is a cross-sectional side view illustrating a second modified example of the fin arrangement. Fig. 14 is a cross-sectional side view illustrating a third modified example of the fin arrangement. Note that Figs. 12 to 14 omit illustration of some of the components placed on the top plate 200, and omit hatching that indicates a cross section of a component.

[0058] The plurality of fins 210 in the cooler 2 according to the above-described embodiment may all have the same shape, or may include fins 210 with two or more different shapes. For example, FIG. 12 illustrates an example in which two types of fins 210 with different dimensions of the first bottom surface (and second bottom surface) are arranged on the underside 202 of the top plate 200. The four fins 210 illustrated in FIG. 12 each have a square first bottom surface, and the dimension D1 of the two fins 210 arranged at both ends in the horizontal direction is larger than the dimension D2 of the two fins 210 arranged in the horizontal center portion. In this way, by increasing (thickening) the dimensions of the fins 210 arranged at both ends in the horizontal direction in a side view, the area of ​​the inclined side surface is increased, making it easier to guide, for example, the refrigerant flowing near the horizontal ends of the refrigerant flow path 260 to the horizontal center portion.

[0059] 13 , the fins 210 may extend in two different directions in a side view. Of the four fins 210 illustrated in FIG. 13 , the two fins 210 on the left side of the horizontal center extend downward at an angle θ2 toward the left end face of the flow path 260, while the two fins 210 on the right side of the horizontal center extend downward at an angle θ2 toward the right end face of the flow path 260. By arranging the fins 210 so that they taper from the lower portion of the refrigerant flow path 260 toward the upper portion in a side view, the refrigerant flowing through the horizontal end of the lower portion of the refrigerant flow path 260 can be uniformly guided to the upper portion in a side view. This can prevent uneven temperature distribution of the refrigerant in a side view. When arranging the fins 210 as described above with reference to Figure 13, for example, a suppression member 273 separate from the fins 210 may be arranged on the upper surface 231 of the bottom plate 230 to suppress the flow of the refrigerant downstream and guide the refrigerant to the upper layer portion.

[0060] Furthermore, for example, as shown in FIG. 14 , the fins 210 may have two or more extension directions in a front view. Of the six fins 210 illustrated in FIG. 14 , the extension angle θ11 of the three upstream fins 210 is smaller than the extension angle θ12 of the three downstream fins 210. As described above with reference to FIG. 9 , the thermal resistance value and pressure loss vary depending on the extension direction angle of the fins 210. Based on the graph in FIG. 9 , for example, if the extension direction angle θ11 of the three upstream fins 210 in a front view is set to 75 degrees and the extension direction angle θ12 of the three downstream fins 210 is set to 85 degrees, the thermal resistance value and pressure loss on the upstream side are smaller than the thermal resistance value and pressure loss on the downstream side. Therefore, in the cooler 2 illustrated in FIG. 14 , for example, the refrigerant flows more easily from upstream to downstream on the upstream side of the flow path 260 than on the downstream side. Therefore, for example, it is possible to suppress the temperature rise of the refrigerant due to heat exchange between the fins 210 and the refrigerant on the upstream side of the flow path 260, and to suppress the decrease in cooling efficiency on the downstream side.

[0061] The cooler 2 according to this embodiment is not limited to the above-described configuration, and for example, the peripheral wall portion 240 may be integral with either the top plate 200 or the bottom plate 230 .

[0062] Fig. 15 is a cross-sectional side view illustrating a second modified example of the cooler configuration. Fig. 16 is a cross-sectional side view illustrating a third modified example of the cooler configuration. Fig. 17 is a cross-sectional side view illustrating a fourth modified example of the cooler configuration. All of these are views corresponding to Fig. 4.

[0063] As shown in FIG. 15 , the cooler 2 may have a peripheral wall portion 240 formed integrally with the bottom plate 230, or as shown in FIG. 16 , the peripheral wall portion 240 may be formed integrally with the top plate 200. Although not shown, the cooler 2 may have, for example, a portion of the peripheral wall portion 240 formed integrally with the bottom plate 230 and the remaining portion of the peripheral wall portion 240 formed integrally with the top plate 200. Furthermore, as shown in FIG. 17 , the cooler 2 may have the top plate 200, the bottom plate 230, and the peripheral wall portion 240 formed integrally, with a cavity formed thereby serving as a flow path 260 for the refrigerant. Such a cooler 2 can be manufactured using, for example, a 3D printer.

[0064] The upper ends of the plurality of fins 210 in the cooler 2 according to this embodiment may be connected to the lower surface 202 of the top plate 200 and the lower ends may be connected to the upper surface of the bottom plate 230 .

[0065] Fig. 18 is a diagram illustrating a fifth modified example of the cooler configuration. Fig. 19 is a diagram illustrating a sixth modified example of the cooler configuration. Figs. 18 and 19 each correspond to a portion including the left end of the cooler 2 illustrated in Fig. 4. In Figs. 18 and 19, the underlined reference numeral 210 is intended to refer to the entire fin.

[0066] In the cooler 2 shown in FIG. 18 , the height H of the fins 210 extending downward from the lower surface 202 of the top plate 200 is approximately equal to the thickness T3 of the peripheral wall portion 240. Therefore, when the top plate 200, the peripheral wall portion 240, and the bottom plate 230 are integrated, the lower surfaces 211 of the fins 210 contact the upper surface 231 of the bottom plate 230. In the cooler 2 shown in FIG. 19 , the multiple fins 210 extend upward not from the lower surface 202 of the top plate 200 but from the upper surface 231 of the bottom plate 230. When multiple fins 210 are formed on the upper surface 231 of the bottom plate 230, the fins 210 are formed so that the farther the fins 210 are from the upper surface 231 of the bottom plate 230, the more downstream they are when viewed from the front. The height from the upper surface 231 of the bottom plate 230 to the upper surface 212 of the fins 210 is approximately equal to the thickness T3 of the peripheral wall portion 240. 19 , the position in the Z direction of the upper surface 212 of the fins 210 is lower than the position in the Z direction of the upper surface 241 of the peripheral wall portion 240. In such a cooler 2, for example, when the top plate 200, the peripheral wall portion 240, and the bottom plate 230 on which the fins 210 are formed are integrated, the upper surface 212 of the fins 210 and the lower surface 202 of the top plate 200 are connected via a member 280 with high thermal conductivity.

[0067] 18 and 19. For example, the lower surfaces 211 of the fins 210 extending downward from the lower surface 202 of the top plate 200 and the upper surface 231 of the bottom plate 230 may be connected via a member 280 having high thermal conductivity. Furthermore, for example, the upper surfaces 212 of the fins 210 extending upward from the upper surface 231 of the bottom plate 230 may be in direct contact with the lower surface 202 of the top plate 200 without the member 280.

[0068] FIG. 20 is a bottom view illustrating a modification of the positional relationship between the inlet and outlet of the refrigerant in the cooler.

[0069] The cooler 2 illustrated in Figures 4 and 14 to 19 has a refrigerant inlet 251 provided on the left end surface in front view and a refrigerant outlet 252 provided on the right end surface. However, the positions of the refrigerant inlet 251 and the outlet 252 in the cooler 2 according to the present invention are not limited to such positions. For example, as shown in Figure 20, the cooler 2 may have the refrigerant inlet 251 and the outlet 252 provided at diagonal positions of the area defining the refrigerant flow path 260 in plan view (bottom view), with the area 213 where the multiple fins 210 are arranged sandwiched between them.

[0070] Similarly, the inlet 251 and the outlet 252 may be located on the side, bottom, or top surface, regardless of the configuration of the top plate 200, bottom plate 230, and peripheral wall portion 240, or one may be located on the side and the other on either the top or bottom surface, or one may be located on the top surface and the other on the bottom surface.

[0071] Fig. 21 is a cross-sectional side view showing a first modified example of the cooler configuration and the positional relationship between the refrigerant inlet and outlet. Fig. 22 is a cross-sectional side view showing a second modified example of the cooler configuration and the positional relationship between the refrigerant inlet and outlet. Fig. 23 is a cross-sectional side view showing a third modified example of the cooler configuration and the positional relationship between the refrigerant inlet and outlet. All of these figures correspond to Fig. 4.

[0072] In the cooler 2 shown in FIG. 21 , the peripheral wall portion 240 is integral with the bottom plate 230, and the inlet 251 and the outlet 252 are formed in the top plate 200 as through-holes that penetrate from the upper surface 204 to the lower surface 202 of the top plate 200. In the cooler 2 shown in FIG. 22 , the peripheral wall portion 240 is integral with the top plate 200, and the inlet 251 and the outlet 252 are formed in the bottom plate 230 as through-holes that penetrate from the upper surface 231 to the lower surface 232 of the bottom plate 230. In the cooler 2 shown in FIG. 23 , the peripheral wall portion 240 is integral with the top plate 200, and the inlet 251 and the outlet 252 are formed in the top plate 200 as through-holes that penetrate from the upper surface 204 to the lower surface 202 of the top plate 200. As described above, the positional relationship between the inlet 251 and the outlet 252 may be other positional relationships. For example, the cooler 2 may have the inlet 251 formed in the top plate 200 and the outlet 252 formed in the bottom plate 230 or the peripheral wall portion 240 .

[0073] The semiconductor device 1 of the above-described embodiment is not limited to a specific application, but is particularly suitable for use in high-temperature environments. For example, the semiconductor device 1 of the above-described embodiment can be applied to a power conversion device such as an inverter device for an in-vehicle motor. With reference to FIG. 24 , a vehicle to which the semiconductor device 1 according to the present invention is applied will be described.

[0074] Fig. 24 is a schematic plan view showing an example of a vehicle to which the semiconductor device according to the present invention is applied. The vehicle 1001 shown in Fig. 24 is, for example, a four-wheeled vehicle equipped with four wheels 1002. The vehicle 1001 may be, for example, an electric vehicle in which the wheels are driven by a motor or the like, or a hybrid vehicle that uses power from an internal combustion engine in addition to a motor. Furthermore, the vehicle to which the semiconductor device 1 is applied is not limited to a four-wheeled vehicle, and may also be a two-wheeled vehicle, a railroad car, or the like.

[0075] The vehicle 1001 includes a drive unit 1003 that applies power to the wheels 1002, and a control device 1004 that controls the drive unit 1003. The drive unit 1003 may be configured with at least one of an engine, a motor, or a hybrid of an engine and a motor, for example.

[0076] The control device 1004 controls (e.g., controls power) the drive unit 1003. The control device 1004 includes the semiconductor device 1 including the cooler 2 according to the above-described embodiment. The semiconductor device 1 can be configured to control power to the drive unit 1003.

[0077] The embodiments of the cooler 2 and semiconductor device 1 according to the present invention are not limited to the above-described embodiments, and may be variously changed, substituted, or modified without departing from the spirit of the technical idea. Furthermore, if the technical idea can be realized in a different way due to technological advances or other derived technologies, it may be implemented using that method. Therefore, the claims cover all embodiments that may fall within the scope of the technical idea.

[0078] The features of the above-described embodiment will be summarized below.

[0079] The cooler according to the above-described embodiment includes a top plate having a heat dissipation surface formed on a first surface thereof, a bottom plate disposed opposite the top plate and thicker than the top plate, a plurality of fins connected to at least the top plate, and a peripheral wall portion formed between the top plate and the bottom plate so as to surround the outer periphery of the plurality of fins. A flow path of a refrigerant is formed by a space surrounded by the top plate, the bottom plate, the plurality of fins, and the peripheral wall portion. A heat dissipation surface is provided on the top plate, the bottom plate, or the peripheral wall portion at one end side in a first direction of the flow path of the refrigerant. and a refrigerant outlet provided on the top plate, the bottom plate, or the peripheral wall portion at the other end side in the first direction, and each of the plurality of fins includes an inclined portion that, in a first plan view when viewed from a second direction perpendicular to the first direction, extends in a direction displaced toward the refrigerant inlet as it moves away from the first surface of the top plate, and that, in a second plan view when viewed from the first direction, extends in a direction displaced toward the second direction as it moves away from the first surface of the top plate.

[0080] In the cooler according to the above embodiment, the angle of the inclined portion of the fin relative to the first surface of the top plate when viewed in the first plane is greater than or equal to 45 degrees and less than 90 degrees, and the angle of the inclined portion of the fin relative to the first surface of the top plate when viewed in the second plane is greater than or equal to 45 degrees and less than 90 degrees.

[0081] In the cooler according to the above embodiment, the refrigerant flow path is configured to suppress the flow of the refrigerant in the first direction and promote agitation of the refrigerant.

[0082] The cooler according to the above embodiment further includes a suppression member, separate from the plurality of fins, disposed in the coolant flow path and configured to suppress the flow of the coolant in the first direction.

[0083] In the cooler according to the above embodiment, each of the plurality of fins is arranged such that the bottom surface of the first surface of the top plate has a square shape when viewed in plan, and the extension direction of the sides of the square is at 45 degrees to the first direction.

[0084] In the cooler according to the above embodiment, the plurality of fins include a plurality of types of fins having different bottom surface dimensions in a plan view of the first surface of the top plate.

[0085] In the cooler according to the above embodiment, the size of the fins arranged at the end portions in the second direction is larger than the size of the fins arranged in the central portion in the second direction.

[0086] In the cooler according to the above embodiment, the plurality of fins include a plurality of types of fins having different combinations of the extension direction of the inclined portion in the first planar view and the extension direction of the inclined portion in the second planar view.

[0087] In the cooler according to the above embodiment, the plurality of fins include fins that, in the second plan view, are displaced toward one end of the second direction as the inclined portion moves away from the top plate, and fins that are displaced toward the other end of the second direction.

[0088] In the cooler according to the above embodiment, the extending direction of the inclined portions of the plurality of fins changes depending on the distance from the upstream side of the refrigerant in the first plan view.

[0089] The semiconductor device according to the above-described embodiment includes the cooler, and a wiring board and a semiconductor element that are arranged on the surface of the top plate opposite to the first surface.

[0090] The vehicle according to the above-described embodiment includes the semiconductor device.

[0091] As described above, the present invention has the effect of improving the cooling performance of a cooler applied to a semiconductor device, and is particularly useful for industrial or electrical semiconductor devices, and vehicles.

[0092] This application is based on Japanese Patent Application No. 2023-100938, filed on June 20, 2023, the contents of which are incorporated herein in their entirety.

Claims

1. A cooling device comprising: a top plate having a heat dissipation surface formed on a first surface thereof; a bottom plate disposed opposite the top plate and thicker than the top plate; a plurality of fins connected to at least the top plate; and a peripheral wall portion formed between the top plate and the bottom plate so as to surround the outer periphery of the plurality of fins; a flow path for a refrigerant is formed by a space surrounded by the top plate, the bottom plate, the plurality of fins, and the peripheral wall portion; and a cooling medium inlet provided on the top plate, the bottom plate, or the peripheral wall portion at one end side in a first direction of the flow path for the refrigerant, and a cooling medium outlet provided on the top plate, the bottom plate, or the peripheral wall portion at the other end side in the first direction; a first plan view of the fins when viewed from a second direction perpendicular to the first direction, the first and second plan views of the fins each include an inclined portion that extends in a direction displaced toward the refrigerant inlet as it moves away from the first surface of the top plate, and that extends in a direction displaced toward the second direction as it moves away from the first surface of the top plate, the second plan view of the fins when viewed from the first direction.

2. A cooler as described in claim 1, wherein the inclined portion of the fin has an angle of 45 degrees or more and less than 90 degrees in the extension direction relative to the first surface of the top plate when viewed in the first plane, and an angle of 45 degrees or more and less than 90 degrees in the extension direction relative to the first surface of the top plate when viewed in the second plane.

3. The cooler of claim 1, wherein the refrigerant flow path is configured to restrict flow of the refrigerant in the first direction to promote agitation of the refrigerant.

4. The cooler according to claim 3, further comprising a suppression member disposed in the flow path of the coolant, separate from the plurality of fins, for suppressing the flow of the coolant in the first direction.

5. A cooler as described in claim 1, wherein each of the plurality of fins has a square bottom shape in a plan view of the first surface of the top plate, and is arranged such that the extension direction of the sides of the square is at an angle of 45 degrees to the first direction.

6. The cooler according to claim 1, wherein the plurality of fins include a plurality of types of fins having different bottom surface dimensions in a plan view of the first surface of the top plate.

7. The cooler according to claim 6, wherein the dimensions of the fins disposed at the ends in the second direction are greater than the dimensions of the fins disposed in the central portion in the second direction.

8. A cooler as described in claim 1, wherein the plurality of fins include a plurality of types of fins having different combinations of the extension direction of the inclined portion when viewed in the first plane and the extension direction of the inclined portion when viewed in the second plane.

9. A cooler as described in claim 1, wherein the plurality of fins include fins that, in the second plan view, are displaced toward one end side in the second direction as the inclined portion moves away from the top plate, and fins that are displaced toward the other end side in the second direction.

10. The cooler according to claim 1, wherein the extension direction of the inclined portions of the plurality of fins changes depending on the distance from the upstream side of the refrigerant when viewed in the first plane.

11. A semiconductor device comprising the cooler according to any one of claims 1 to 10, and a wiring board and a semiconductor element disposed on the surface of the top plate opposite to the first surface.

12. A vehicle comprising the semiconductor device according to claim 11.