Semiconductor device and vehicle

Abstract

The present application provides a semiconductor device and a vehicle, which can suppress a decrease in cooling performance while ensuring rigidity and corrosion resistance. A top plate (21) is rectangular in plan view, and a cooling region (21b) in which a plurality of fins (24f) are arranged is provided in the central portion of the back surface in the length direction, and a communication region (21c, 21d) is provided on both sides of the cooling region (21b). A side wall (22) is connected in a ring shape on the back surface of the top plate (21) so as to include the cooling region (21b) and the communication region (21c, 21d). The thickness (T2) of the cooling region (21b) of the top plate (21) is thinner than the outer edge thickness (T1) of the outer edge region (21e, 21f) of the top plate (21) which is more outward than the side wall (22). Therefore, the distance from the front surface of the cooling region (21b) of the top plate (21) to the plurality of fins (24f) is shortened. Moreover, heat of the semiconductor module (10) is easily conducted to the plurality of fins (24f), and the cooling capacity of the refrigerant is improved.

Description

Technical Field

[0001] This invention relates to semiconductor devices and vehicles. Background Technology

[0002] To maintain the reliability of semiconductor modules, including power semiconductor components, the semiconductor modules are mounted on a cooling device. This allows for efficient and stable cooling of the power semiconductor components.

[0003] The cooling device has multiple heat sinks formed within its top plate. Furthermore, it has inlet and outlet ports communicating with the interior. The refrigerant circulates by flowing into the cooling device from the inlet, circulating among the heat sinks, and exiting from the outlet. If a semiconductor module is positioned on the front side of the top plate corresponding to the heat sinks, heat is conducted from the semiconductor module via the heat sinks through the top plate. The heat conducted to the heat sinks is dissipated by the refrigerant circulating within the cooling device. As a result, the power semiconductor components are cooled.

[0004] Existing technical documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2005-079386

[0006] Patent Document 2: Japanese Patent Application Publication No. 2010-212577 Summary of the Invention

[0007] Technical issues

[0008] The top plate of such a cooling device is made relatively thick to ensure rigidity and to prevent liquid leakage caused by refrigerant corrosion. However, if the top plate is too thick, heat dissipation is reduced, and the cooling performance of the cooling device is decreased.

[0009] The present invention was made in view of the above-mentioned problems, and its object is to provide a semiconductor device that can suppress the reduction of cooling performance while ensuring rigidity and corrosion resistance, as well as a vehicle including such a semiconductor device.

[0010] Technical solution

[0011] According to one aspect of the present invention, a semiconductor device is provided, comprising: a semiconductor module having a semiconductor chip and an insulating circuit substrate on which the semiconductor chip is mounted; and a cooling device having a top plate on which the semiconductor module is disposed on the front side, and a sidewall connection region for connecting an annular sidewalls is provided on the back side of the top plate, the top plate being rectangular in plan view, a cooling region having a plurality of heat sinks disposed along the length direction at the center of the back side, a first connecting region and a second connecting region being respectively provided on both sides of the cooling region along the width direction, the sidewall connection region being annular on the back side of the top plate in a manner including the cooling region, the first connecting region and the second connecting region, and the thickness of the cooling region being thinner than the outer edge thickness of the outer edge region of the top plate that is further outward than the sidewall connection region.

[0012] In addition, a vehicle including the aforementioned semiconductor device is provided.

[0013] Invention Effects

[0014] According to the disclosed technology, it is possible to suppress the reduction in cooling performance and prevent a decrease in the reliability of semiconductor devices and vehicles including semiconductor devices.

[0015] The above and other objects, features and advantages of the present invention will become clear from the following description in conjunction with the accompanying drawings, which illustrate preferred embodiments as examples of the present invention. Attached Figure Description

[0016] Figure 1 This is a perspective view of the semiconductor device according to the first embodiment.

[0017] Figure 2 This is a diagram illustrating the cooling device included in the semiconductor device of the first embodiment.

[0018] Figure 3 This is a top view of the cooling device included in the semiconductor device of the first embodiment.

[0019] Figure 4 This is a cross-sectional view of the cooling device included in the semiconductor device of the first embodiment.

[0020] Figure 5 This diagram illustrates the flow of refrigerant in the cooling device of the first embodiment.

[0021] Figure 6 This is a cross-sectional view of another cooling device included in the semiconductor device of the first embodiment.

[0022] Figure 7 This is a cross-sectional view of the main part of the cooling device included in the semiconductor device of the first embodiment, variant 1-1.

[0023] Figure 8 This is an enlarged cross-sectional view of the main part of the cooling device included in the semiconductor device of the first embodiment, variant 1-1.

[0024] Figure 9 This is a cross-sectional view of the main part of the cooling device included in the semiconductor device of the first embodiment, variations 1-2.

[0025] Figure 10 This is a cross-sectional view of the main part of the cooling device included in the semiconductor device of the first embodiment, variations 1-3.

[0026] Figure 11 This is a cross-sectional view of the cooling device included in the semiconductor device of the second embodiment.

[0027] Figure 12 This is a top view of the cooling device included in the semiconductor device of the second embodiment.

[0028] Figure 13 This is a cross-sectional view of the cooling device included in the semiconductor device of the second embodiment, variant 2-1.

[0029] Figure 14 This is a top view of the cooling device included in the semiconductor device of the second embodiment, variant 2-1.

[0030] Figure 15 This is a cross-sectional view of the main part of the cooling device included in the semiconductor device of the second embodiment, variant 2-2.

[0031] Figure 16 This is a cross-sectional view of the main part of the cooling device included in the semiconductor device of the second embodiment, variations 2-3.

[0032] Figure 17 This is a schematic diagram of the vehicle.

[0033] Figure 18 It is a diagram of the equivalent circuit included in a semiconductor device.

[0034] Symbol Explanation

[0035] 1: Semiconductor devices

[0036] 10: Semiconductor Module

[0037] 11: Insulated circuit board

[0038] 11a: Insulation board

[0039] 11b: Circuit diagram

[0040] 11c: Metal plate

[0041] 12, 12a1~12a6, 12b1~12b6, 12c1~12c6: Semiconductor chips

[0042] 13: Joining components (solder)

[0043] 14: Joining components (brazing filler metal)

[0044] 20, 120: Cooling device

[0045] 20a, 20b: Long side

[0046] 20c, 20d: Short side

[0047] 20e: Fastening hole

[0048] 20e1: Fastening and Reinforcing Section

[0049] 21: Top Slab

[0050] 21a: Flow path area

[0051] 21b: Cooling area

[0052] 21c, 21d: Connected regions

[0053] 21c1: Side of cooling area

[0054] 21c2: Side of the outer edge region

[0055] 21c3: Middle section

[0056] 21e, 21f: Outer edge region

[0057] 21g, 21g1, 21g2: Step section

[0058] 21h, 21i: Extended area

[0059] 22: Sidewall

[0060] 22a: Sidewall connection area

[0061] 23: Base Plate

[0062] 23a: Inlet

[0063] 23b: Outlet

[0064] 23c1, 23c2: Rubber gaskets

[0065] 23d1, 23d2: Drainage head

[0066] 23e1, 23e2: Drainage pipes

[0067] 24: Flow path part

[0068] 24a: Cooling section

[0069] 24b, 24c: Connecting parts

[0070] 24d, 24e: Threaded frame

[0071] 24f: Heatsink

[0072] 25: Softening board

[0073] 30: Vehicles

[0074] 31: Control device Detailed Implementation

[0075] The embodiments will now be described with reference to the accompanying drawings. It should be noted that in the following description, "front" and "upper surface" refer to the XY planes facing upwards (+Z direction) in the semiconductor device 1 and cooling devices 20, 120 shown in the figures. Similarly, in the semiconductor device 1 and cooling devices 20, 120 shown in the figures, "upper" indicates the direction facing upwards (+Z direction). In the semiconductor device 1 and cooling device 20 shown in the figures, "back side" and "lower surface" refer to the XY planes facing downwards (-Z direction). Similarly, in the semiconductor device 1 and cooling devices 20, 120 shown in the figures, "lower" indicates the direction facing downwards (-Z direction). The same directionality may be indicated in other figures as needed. "Front side," "upper surface," "upper," "back side," "lower surface," "lower," and "side" are merely convenient expressions for determining relative positional relationships and do not limit the technical concept of the invention. For example, "upper" and "lower" do not necessarily mean the vertical direction relative to the ground. That is, the directions of "upper" and "lower" are not limited to the direction of gravity. Furthermore, in the following description, "main ingredient" means that it contains 80% or more by volume.

[0076] [First Implementation Method]

[0077] First, using Figure 1 The semiconductor device is described. Figure 1 This is a perspective view of the semiconductor device according to the first embodiment. The semiconductor device 1 includes a semiconductor module 10 and a cooling device 20 on which the semiconductor module 10 is mounted. It should be noted that the semiconductor module 10 can be referenced... Figure 4 .

[0078] The semiconductor module 10 has an insulating circuit board 11 and a plurality of semiconductor chips 12 bonded to the front side of the insulating circuit board 11. Furthermore, the semiconductor module 10 may also have wiring components (not shown) that electrically connect the front side of the insulating circuit board 11 to the main electrodes of the semiconductor chips 12. Wiring components may include, for example, bonding wires, busbars, or lead frames.

[0079] Furthermore, the semiconductor module 10 may also have the aforementioned components mounted on a heat sink and covered by a housing. The housing may also be bonded to the outer periphery of the heat sink on which the semiconductor module 10 is mounted via an adhesive. Additionally, the housing may be sealed by a sealing component. It should be noted that the sealing component comprises a thermosetting resin and a filler contained within the thermosetting resin as a filler. Examples of thermosetting resins include epoxy resin, phenolic resin, and maleimide resin. Examples of fillers include silicon dioxide, aluminum oxide, boron nitride, or aluminum nitride. As an example of such a sealing component, it comprises epoxy resin and a filler as a filler. Examples of fillers include silicon dioxide, aluminum oxide, boron nitride, or aluminum nitride.

[0080] The insulating circuit board 11 includes an insulating plate 11a, a circuit pattern 11b disposed on the front side of the insulating plate 11a, and a metal plate 11c disposed on the back side of the insulating plate 11a (see reference). Figure 4 The insulating plate 11a and the metal plate 11c are rectangular in shape when viewed from above. Furthermore, the corners of the insulating plate 11a and the metal plate 11c may be chamfered (R-shaped or C-shaped). The metal plate 11c is smaller than the insulating plate 11a when viewed from above and is formed inside the insulating plate 11a. The insulating plate 11a is made of a material with excellent insulation and thermal conductivity. Such an insulating plate 11a is made of ceramic or insulating resin. The ceramic is alumina, aluminum nitride, silicon nitride, etc. The insulating resin is a paper-phenol substrate, a paper epoxy board, a glass composite substrate, a glass epoxy board, etc. The thickness of the insulating plate 11a is 0.2 mm or more and 2.5 mm or less.

[0081] The circuit pattern 11b is made of a metal with excellent electrical conductivity. Such a metal is, for example, copper, aluminum, or an alloy with at least one of these as a main component. Furthermore, the thickness of the circuit pattern 11b is 0.1 mm or more and 2.0 mm or less. To improve corrosion resistance, the surface of the circuit pattern 11b may also be plated. In this case, the plating material used is, for example, nickel, nickel-phosphorus alloy, or nickel-boron alloy. It should be noted that... Figure 4 The circuit pattern 11b shown is an example. The number, shape, size, etc. of the circuit patterns 11b can also be selected as needed.

[0082] The area of ​​the metal plate 11c is smaller than that of the insulating plate 11a, but larger than the area where the circuit pattern 11b is formed, and it is rectangular like the insulating plate 11a. Furthermore, the corners may be chamfered (R-shaped or C-shaped). The metal plate 11c is smaller than the insulating plate 11a and is formed on the entire surface of the insulating plate 11a except for the edges. The metal plate 11c can be primarily composed of a metal with excellent thermal conductivity. The metal may be, for example, copper, aluminum, or an alloy containing at least one of these. Furthermore, the thickness of the metal plate 11c is 0.1 mm or more and 2.5 mm or less. To improve the corrosion resistance of the metal plate 11c, a plating process may be performed. In this case, the plating material used may be, for example, nickel, a nickel-phosphorus alloy, or a nickel-boron alloy.

[0083] As an insulating circuit board 11 having such a structure, for example, a DCB (Direct Copper Bonding) substrate, an AMB (Active Metal Brazed) substrate, or a resin insulating substrate can be used.

[0084] The insulating circuit board 11 can also be mounted on the cooling device 20 via the bonding member 14. The bonding member 14 is solder, brazing filler metal, or a sintered metal. Lead-free solder is used. Lead-free solder, for example, has an alloy containing at least two of tin, silver, copper, zinc, antimony, indium, and bismuth as its main component. In addition, the solder may also contain additives. Additives, for example, are nickel, germanium, cobalt, or silicon. By containing additives, the solder's wettability, gloss, and bond strength are improved, thereby increasing reliability. Brazing filler metal, for example, has at least one of aluminum alloy, titanium alloy, magnesium alloy, zirconium alloy, and silicon alloy as its main component. The insulating circuit board 11 can be bonded by brazing using such a bonding member 14. The sintered metal is, for example, composed mainly of silver and silver alloys. Alternatively, the bonding member 14 can be a thermal interface material. Thermal interface materials, for example, are adhesive materials containing elastomer sheets, RTV (Room Temperature Vulcanization) rubber, gels, phase change materials, etc. By mounting the semiconductor module 10 onto the cooling device 20 through such solder or thermal interface material, the heat dissipation of the semiconductor module 10 can be improved.

[0085] Semiconductor chip 12 includes power device elements primarily composed of silicon. It should be noted that semiconductor chip 12 is a general term for semiconductor chips 12a1 to 12a6 and 12b1 to 12b6. Furthermore, the thickness of semiconductor chip 12 is, for example, 40 μm or more and 250 μm or less. The power device elements are switching elements or diode elements. Semiconductor chips 12a1 to 12a6 include switching elements. Switching elements are, for example, IGBTs (Insulated Gate Bipolar Transistors) or power MOSFETs (Metal Oxide Semiconductor Field Effect Transistors). Such semiconductor chips 12a1 to 12a6, for example, have a drain (or collector) as the main electrode on the back side, and a gate and a source (or emitter) as the control electrode and main electrode on the front side. Semiconductor chips 12b1 to 12b6 include diode elements. Diode elements include, for example, SBD (Schottky Barrier Diode), PiN (P-intrinsic-N) diodes, and their FWD (Free Wheeling Diode). Such semiconductor chips 12b1 to 12b6 have a cathode as the main electrode on the back side and a anode as the main electrode on the front side.

[0086] Semiconductor chip 12 is selected from at least one of a switching element and a diode element as needed, and its back side is mechanically and electrically bonded to a predetermined circuit pattern 11b via a bonding member 13. The bonding member 13 is solder or a sintered metal. Lead-free solder is used. Lead-free solder is, for example, an alloy containing at least two of tin, silver, copper, zinc, antimony, indium, and bismuth as its main component. In addition, the solder may also contain additives. Additives are, for example, nickel, germanium, cobalt, or silicon. By including additives, the solder's wettability, gloss, and bonding strength are improved, thereby improving reliability. The metal used in the sintered metal is, for example, silver and silver alloys.

[0087] Alternatively, an RC (Reverse-Conducting)-IGBT, which combines the functions of IGBT and FWD, can be used to replace semiconductor chip 12 (see reference). Figure 18 The semiconductor chip 12 can be a power MOSFET made primarily of silicon carbide. Such a semiconductor chip 12 has an input electrode (drain) as the main electrode on its back side, a gate electrode as the control electrode, and an output electrode (source electrode) as the main electrode on its front side.

[0088] In addition, depending on the needs, it can also replace the semiconductor chip 12, or be configured together with the semiconductor chip 12, such as a lead frame, external connection terminals (pin terminals, contact parts, etc.), electronic components (thermometers, current sensors).

[0089] The cooling device 20 has an inlet for refrigerant to flow into the interior and an outlet for refrigerant flowing out of the interior. The cooling device 20 cools the semiconductor module 10 by dissipating heat from the semiconductor module 10 via the refrigerant. It should be noted that the refrigerant used may be, for example, water, antifreeze (ethylene glycol aqueous solution), or long-life coolant (LLC). Such a cooling device 20, when viewed from above, is rectangular in shape including long sides 20a, 20b and short sides 20c, 20d. Furthermore, the cooling device 20, when viewed from above, has fastening holes 20e formed at at least at each of its four corners. The fastening holes 20e are through holes for inserting bosses or the like of external devices for mounting the semiconductor device 1 and fastening it to the external device. Figure 1 The diagram shows three semiconductor modules 10 mounted along the long sides 20a and 20b in the central portion of the front side of such a cooling device 20. The number of semiconductor modules 10 is not limited to three. Furthermore, as long as the semiconductor modules 10 are positioned in the central portion of the cooling device 20 (the cooling area described later), their placement and size are not limited to... Figure 1 In addition, the cooling device 20 may also include a pump and a heat dissipation device (radiator). The pump draws refrigerant into the inlet of the cooling device 20 and circulates the refrigerant by drawing it back into the inlet from the outlet. The heat dissipation device dissipates the heat from the refrigerant, which has been conducted from the semiconductor module 10, to the outside.

[0090] Next, using Figures 2-4 The details of the cooling device 20 are described below. Figure 2 This diagram illustrates the cooling device included in the semiconductor device of the first embodiment. Figure 3 This is a top view of the cooling device included in the semiconductor device of the first embodiment. Figure 4 This is a cross-sectional view of the cooling device included in the semiconductor device of the first embodiment. It should be noted that... Figure 3 The internal structure is shown in perspective, with the cooling device 20 viewed from above. Figure 4 yes Figure 3 A cross-sectional view at the point marked by a single-dotted line XX.

[0091] The cooling device 20 has a top plate 21, a side wall 22 connected annularly to the back of the top plate 21, and a bottom plate 23 opposite to the top plate 21 and connected to the back of the side wall 22. The top plate 21, when viewed from above, is rectangular in shape, surrounded by long sides 20a and 20b and short sides 20c and 20d, and has fastening holes 20e formed at each of its four corners. The corners of the top plate 21 can also be R-machined when viewed from above.

[0092] In addition, such as Figure 3 As shown, the top plate 21 is divided into a flow path region 21a and outer edge regions 21e and 21f. It should be noted that, as described later, a sidewall 22 is connected to the back side of the top plate 21. The flow path region 21a is the region surrounded by the sidewall 22. The flow path region 21a is also divided into a cooling region 21b and connecting regions 21c and 21d parallel to the long sides 20a and 20b. The cooling region 21b is a centrally rectangular region parallel to the long sides 20a and 20b (length direction) of the top plate 21. In the cooling region 21b on the front side of the top plate 21, multiple semiconductor modules 10 are arranged in a row along the Y direction. It should be noted that... Figure 3 In the diagram, the arrangement of the semiconductor module 10 is indicated by dashed lines. Multiple heat sinks 24f are formed in the cooling region 21b on the back side of the top plate 21. The thickness (length in the Z direction) of the top plate 21 varies depending on the region, as described later, but the maximum thickness T1 is 2.0 mm or more and 5.0 mm or less. Furthermore, the minimum thickness T2 is 40% or more and 60% or less of the thickness T1, for example, 0.8 mm or more and 3.2 mm or less.

[0093] Multiple heat sinks 24f extend to connect the cooling area 21b on the back of the top plate 21 to the bottom plate 23. The height (length in the Z direction) of the multiple heat sinks 24f is 1.5 mm or more and 15.0 mm or less. Preferably, it is 2.0 mm or more and 12.0 mm or less. It should be noted that in Figure 3 The plane of heat sink 24f is shown in the figure. Figure 5 The side of heatsink 24f is shown. However, in Figure 5 The image shows heatsink 24f schematically, and it is not necessarily the same as the image. Figure 3Consistent. In cooling region 21b, the number of heat sinks 24f arranged along the long sides 20a, 20b is greater than the number of heat sinks 24f arranged along the short sides 20c, 20d. Cooling region 21b includes the area where heat sinks 24f are provided and the flow path between the heat sinks 24f. It should be noted that the spacing between adjacent heat sinks 24f may also be narrower than the width of the heat sink 24f itself. The heat sink 24f has an upper end and a lower end in the ±Z direction. The upper end of the heat sink 24f is thermally and mechanically connected to the back side of the top plate 21. The upper end of the heat sink 24f is integrally formed with the top plate 21, that is, the heat sink 24f protrudes integrally from the back side of the top plate 21 in the -Z direction. On the other hand, the lower end of the heat sink 24f is fixed to the front side of the bottom plate 23 (inner side of the cooling device 20). In addition, the heat sink 24f extends in the Z direction. This extension direction is approximately orthogonal to the main surfaces of the top plate 21 and the bottom plate 23. The heat sinks 24f can be pin-type heat sinks. Furthermore, the cross-sectional shape of each of the multiple heat sinks 24f parallel to the main surface of the top plate 21 is rectangular. Figure 3 In the middle, it is rhomboid in shape. Therefore, compared with the case where the cross-sectional shape of the heat sink 24f is circular, the surface area of ​​the heat sink 24f in contact with the refrigerant can be increased, thereby improving the heat dissipation efficiency.

[0094] Furthermore, the multiple heat sinks 24f can also be arranged in the cooling region 21b of the top plate 21 such that, when refrigerant flows into the cooling section 24a (described later), none of the sides of the rectangle are orthogonal to the main flow direction of the refrigerant in the cooling section 24a. In this embodiment, the main flow direction of the refrigerant in the cooling region 21b is the X direction (the direction parallel to the short sides 20c, 20d). The multiple heat sinks 24f are arranged in the cooling region 21b such that none of the sides of the rectangle are orthogonal to the X direction. More specifically, the multiple heat sinks 24f are arranged such that none of the sides of the rectangle are orthogonal to the X direction, one diagonal is parallel to the Y direction (long sides 20a, 20b), and the other diagonal is parallel to the X direction. Alternatively, the multiple heat sinks 24f can also be arranged such that none of the sides of the rectangle are orthogonal to the X direction, one diagonal is inclined relative to the Y direction, and the other diagonal is inclined relative to the X direction. Compared to the case where multiple heat sinks 24f are arranged in the cooling region 21b with any side of the rectangle orthogonal to the flow direction, any of the above structures can reduce the flow rate loss of the refrigerant flowing in the cooling section 24a and improve the heat dissipation efficiency.

[0095] In addition, the heatsink 24f is Figure 3In the XY plane shown, a rhombus is formed where the shorter sides 20c and 20d are longer than the longer sides 20a and 20b. The length of each side of the rhombus cross-section of the heat sink 24f can be 0.5mm or more and 0.8mm or less. Radius machining can also be performed at each corner of the rhombus cross-section. It should be noted that the cross-sectional shape of each of the multiple heat sinks 24f can also be polygonal, for example, square. Alternatively, the cross-sectional shape of each of the multiple heat sinks 24f can also be circular, for example, a perfect circle. Furthermore, the multiple heat sinks 24f can also be arranged in a predetermined pattern within the cooling region 21b. Figure 3 As shown, multiple heat sinks 24f are arranged in an alternating pattern. Multiple heat sinks 24f can also be arranged in a grid pattern within the cooling region 21b.

[0096] The connecting regions 21c and 21d are adjacent to both sides of the cooling region 21b in the top plate 21, and are regions along the cooling region 21b. Therefore, the connecting regions 21c and 21d are regions from the cooling region 21b to the sidewall 22 (on the long sides 20a and 20b). Figure 3 In this case, the connecting regions 21c and 21d are trapezoidal. It should be noted that, depending on the area enclosed by the sidewall 22, the connecting regions 21c and 21d can also be rectangular, semi-circular, or mountain-shaped with multiple peaks. Furthermore, when viewed from above, the corners of the connecting regions 21c and 21d can be chamfered with an R-shape. This involves R-machining the connecting portions of the sidewall 22 constituting the connecting regions 21c and 21d. The refrigerant flowing through the connecting regions 21c and 21d does not linger at the smooth corners and flows easily. This prevents corrosion at such corners. Furthermore, the connecting regions 21c and 21d do not necessarily need to be symmetrical. Additionally, the outlet 23b and inlet 23a are formed near the shorter sides 20c and 20d, respectively, corresponding to the connecting regions 21c and 21d, as detailed later. Furthermore, the outlet 23b and inlet 23a are formed at the center relative to the X-direction of the connecting regions 21c and 21d. The connecting regions 21c and 21d can also be shaped to facilitate the flow of refrigerant out and in relative to the outlet 23b and the inlet 23a. For example, the connecting region 21c can also be shaped to narrow as it approaches the outlet 23b, so as to push the refrigerant toward the outlet 23b.

[0097] The outer edge regions 21e and 21f are the regions outside the flow path region 21a (cooling region 21b and connecting regions 21c and 21d) in the top plate 21. That is, the outer edge regions 21e and 21f are the regions from the sidewall 22 of the top plate 21 to the outer edge of the top plate 21 when viewed from above. The fastening hole 20e and the fastening reinforcement 20e1 described above are formed in the outer edge regions 21e and 21f. The thickness of the outer edge regions 21e and 21f of the top plate 21 is the maximum thickness T1 in the top plate 21.

[0098] The thickness of at least the cooling region 21b of such a top plate 21 is thickness T2, which is thinner than the thickness T1 of the outer edge regions 21e and 21f. However, the connecting regions 21c and 21d of the top plate 21 are also of thickness T2. Furthermore, the front side of the top plate 21 on which the semiconductor module 10 is mounted is formed by a flat surface without steps in the thickness direction (Z direction), and forms a single plane. The cooling region 21b and the connecting regions 21c and 21d on the back side of the top plate 21 are recessed towards the front side.

[0099] The sidewall 22 forms a ring around the cooling region 21b and the connecting regions 21c and 21d on the back side of the top plate 21. The upper end of the sidewall 22 in the +Z direction is fixed to the back side of the top plate 21. Furthermore, the lower end of the sidewall 22 in the -Z direction is fixed to the front side of the bottom plate 23. Figure 3 In this case, the sidewall 22 has eight sides, including a portion parallel to the short sides 20c and 20d along the cooling region 21b, a portion parallel to the long sides 20a and 20b along the connecting regions 21c and 21d, and a portion connecting these portions. The corners of the connecting portions on the inner side of the annular sidewall 22 may also be R-machined. The sidewall 22 includes a rectangular cooling region 21b when viewed from above. If connecting regions 21c and 21d are included on both sides of the cooling region 21b, it may not be composed of eight sides. Furthermore, the height (length in the Z direction) of the sidewall 22 corresponds to the height of the plurality of heat sinks 24f, for example, it is 1.5 mm or more and 15.0 mm or less. Preferably, it is 2.0 mm or more and 12.0 mm or less. It should be noted that when the height of the sidewall 22 is different on the outer edge regions 21e and 21f side and on the connecting regions 21c and 21d side, the height of the sidewall 22 refers to the height on the connecting regions 21c and 21d side. In this case, the height of the sidewall 22 on the connecting regions 21c and 21d can be the height of the sidewall 22 on the outer edge regions 21e and 21f plus the length obtained by subtracting the thickness T2 of the top plate 21 on the connecting regions 21c and 21d from the thickness T1 of the top plate 21 on the outer edge regions 21e and 21f. Furthermore, the thickness of the sidewall 22 (length in the X direction) is a thickness that, as described later, is held between the top plate 21 and the bottom plate 23 to maintain the strength of the cooling device 20 and to prevent a decrease in cooling performance; for example, it is 1.0 mm or more and 3.0 mm or less.

[0100] Furthermore, a fastening reinforcement 20e1 can be formed on the back side of the top plate 21 (inside the cooling device 20) around the fastening hole 20e. The fastening reinforcement 20e1 has a through hole corresponding to the fastening hole 20e. The side wall 22 is held between the top plate 21 and the bottom plate 23, thus maintaining the strength of the cooling device 20. Therefore, the height of the fastening reinforcement 20e1 is approximately the same as the height of the side wall 22. More specifically, the height of the fastening reinforcement 20e1 is approximately the same as the height of the outer edge region 21e side of the side wall 22. In addition, the height of the fastening reinforcement 20e1 can be approximately the same as the height obtained by subtracting the height of the step portion 21g (described later) from the height of the plurality of heat sinks 24f (T1-T2). The width of the fastening reinforcement 20e1 (the radial length from the center of the fastening hole 20e when viewed from above) is more than 0.7 times and less than 2.0 times the diameter of the fastening hole 20e.

[0101] The base plate 23 is flat and has the same shape as the top plate 21 when viewed from above. Specifically, the base plate 23 is rectangular in shape, surrounded by a long side and a short side, and has fastening holes at each of its four corners corresponding to those of the top plate 21. Furthermore, the corners of the base plate 23 can be rounded. The front and back surfaces of the base plate 23 are parallel. The back surface of the base plate 23 is flat and without steps, forming the same plane. The back surface of the base plate 23 can also be parallel to the front surface of the top plate 21. The base plate 23 has an inlet 23a and an outlet 23b for refrigerant to flow in and out. The inlet 23a is formed on the side of the long side 20b and the side of the short side 20d, corresponding to the connecting region 21d. The outlet 23b is formed on the side of the long side 20a and the side of the short side 20c, corresponding to the connecting region 21c. That is, the inlet 23a and the outlet 23b are each formed at a point symmetrical position relative to the center point of the base plate 23. If such a base plate 23 is connected to the side wall 22, the fastening reinforcement 20e1 is connected to the periphery of the fastening holes of the base plate 23. The base plate 23 needs to have a thickness that maintains the overall strength of the cooling device 20 without reducing the cooling performance. In addition, the base plate 23 needs to have the strength to install drain pipes at the inlet 23a and outlet 23b, as described later. Therefore, the thickness T0 of the base plate 23 is at least 1.0 times and less than 5.0 times the thickness T1 of the outer edge regions 21e and 21f of the top plate 21. More preferably, it is at least 2.0 times and less than 3.0 times. For example, the thickness T0 of the base plate 23 is preferably at least 2.0 mm and less than 10.0 mm.

[0102] The internal structure of the cooling device 20 thus configured consists of a flow path section 24 surrounded by a top plate 21, side walls 22, and a bottom plate 23. The flow path section 24 is further divided into a cooling section 24a corresponding to the cooling region 21b and connecting sections 24b and 24c corresponding to the connecting regions 21c and 21d. Multiple heat sinks 24f connecting the top plate 21 and the bottom plate 23 extend in the cooling section 24a. The connecting sections 24b and 24c are formed by the connecting regions 21c and 21d of the top plate 21, the side walls 22, and the bottom plate 23. The connecting section 24c is connected to the cooling section 24a. Refrigerant flowing in from the inlet 23a flows from the connecting section 24c to the cooling section 24a. The connecting section 24b is connected to the cooling section 24a. Refrigerant from the cooling section 24a flows into the connecting section 24b and flows out from the outlet 23b. It should be noted that the flow of refrigerant in the cooling device 20 will be explained later. Furthermore, in the cooling device 20, in the outer edge regions 21e and 21f of the top plate 21, threaded frames 24d and 24e are formed by the outer side of the side wall 22 and the bottom plate 23.

[0103] The cooling device 20 is constructed primarily of a metal with excellent thermal conductivity. The metal is, for example, copper, aluminum, or an alloy containing at least one of these. To improve the corrosion resistance of the cooling device 20, a plating process may be performed. In this case, the plating material used is, for example, nickel, a nickel-phosphorus alloy, or a nickel-boron alloy. Furthermore, the top plate 21, on which multiple heat sinks 24f are formed, is formed, for example, by forging or casting (die casting). In the case of forging, a block-shaped component primarily composed of the aforementioned metal is pressed using a mold to plastically deform it, thereby obtaining a top plate 21 with multiple heat sinks 24f and sidewalls 22. In the case of die casting, molten die casting material is poured into a predetermined mold, cooled, and then removed from the mold, thereby obtaining a top plate 21 with multiple heat sinks 24f and sidewalls 22. Furthermore, the die casting material in this case is, for example, an aluminum-based alloy. Alternatively, the top plate 21, which has multiple heat sinks 24f and sidewalls 22, can also be formed by machining a block-shaped component with the aforementioned metal as its main component.

[0104] The base plate 23 is joined to the multiple heat sinks 24f and sidewalls 22 of the top plate 21. This joining is performed by brazing. Therefore, the back sides of the sidewalls 22 and the ends of the heat sinks 24f, which extend from the main surface (back side) of the top plate 21, are joined to the front side of the base plate 23 via brazing filler metal. In the case where the top plate 21 is formed by casting, the brazing filler metal used is a material with a lower melting point than the die-casting material. Such a filler metal is, for example, an alloy with aluminum as its main component.

[0105] It should be noted that a separate fastening reinforcement 20e1 may also be formed relative to the top plate 21 and joined to the bottom plate 23 by brazing. Furthermore, in this embodiment, a plurality of heat sinks 24f are shown connected to the top plate 21. However, this is not a limitation; a plurality of heat sinks 24f may also be formed in the area of ​​the bottom plate 23 corresponding to the cooling area 21b. Thus, the cooling device 20 is obtained.

[0106] Next, using Figure 5 (as well as Figure 3 The flow of refrigerant in the cooling device 20 will be explained. Figure 5 This is a diagram illustrating the flow of refrigerant in the cooling device of the first embodiment. It should be noted that... Figure 5 Corresponding to Figure 4 .also, Figure 5 The dashed arrows indicate the direction of refrigerant flow. Figure 3 The dashed arrow is the same.

[0107] Inside the cooling unit 20, as described above, the refrigerant is circulated by a pump. During refrigerant circulation, a drain head 23d1 is installed at the inlet 23a, separated by an annular rubber gasket 23c1 surrounding the inlet 23a. A drain pipe 23e1 is installed at the drain head 23d1. Furthermore, at the outlet 23b, a drain head 23d2 is also installed, separated by an annular rubber gasket 23c2 surrounding the outlet 23b. A drain pipe 23e2 is installed at the drain head 23d2. The pump is connected to the drain pipes 23e1 and 23e2.

[0108] like Figure 3 As shown, refrigerant flowing in from inlet 23a flows into connecting portion 24c and expands within it. The refrigerant flowing into connecting portion 24c expands both towards the short side 20c (Y direction) and towards the long side 20a (X direction). Alternatively, if the refrigerant flows in from inlet 23a, it expands directly towards the long side 20a (X direction). Thus, the refrigerant flows into the entire side of cooling portion 24a opposite to the long side 20b.

[0109] like Figure 5As shown, the refrigerant flowing into the cooling section 24a (on the side of the long side 20b) flows towards the long side 20a (X direction) between the multiple heat sinks 24f. Heat from the heated semiconductor module 10 is conducted to the multiple heat sinks 24f via the top plate 21. The refrigerant is heated from the multiple heat sinks 24f as it flows between them. In the cooling device 20, the thickness T2 of the cooling region 21b of the top plate 21 is configured to be thinner than the thickness T1 of the outer edge regions 21e and 21f. That is, the distance from the front of the cooling region 21b of the top plate 21 to the multiple heat sinks 24f is shortened. Therefore, heat from the semiconductor module 10 is easily conducted to the multiple heat sinks 24f. More heat can be conducted to the refrigerant flowing between the heat sinks 24f, improving cooling performance.

[0110] like Figure 3 (as well as Figure 5 As shown, the heated refrigerant flows from the side of the cooling section 24a opposite to the long side 20a into the connecting section 24b, and flows out from the outlet 23b to the outside. At this time, the refrigerant flows out while still containing heat conducted from the multiple heat sinks 24f. The outflowing refrigerant is cooled by the heat dissipation device and then flows back into the cooling device 20 from the inlet 23a by the pump. Through the circulation of the refrigerant relative to the cooling device 20, the heat of the semiconductor module 10 is discharged to the outside, thereby cooling the semiconductor module 10.

[0111] Furthermore, in the cooling device 20, in addition to the cooling region 21b of the top plate 21, the thickness T2 of the connecting regions 21d and 21c is also configured to be thinner than the thickness T1 of the outer edge regions 21e and 21f. That is, the volume (cross-sectional area) of the cooling section 24a and the connecting sections 24b and 24c is increased. Therefore, the pressure loss of the refrigerant flowing in the cooling section 24a and the connecting sections 24b and 24c is reduced, and the refrigerant can easily flow in the cooling section 24a and the connecting sections 24b and 24c at a substantially constant flow rate without slowing down the flow rate. Since the flow rate of the refrigerant among the multiple heat sinks 24f does not decrease, a reduction in cooling capacity is prevented.

[0112] The aforementioned semiconductor device 1 includes: a semiconductor module 10 having a semiconductor chip 12 and an insulating circuit board 11 on which the semiconductor chip 12 is mounted; and a cooling device 20 having a top plate 21 on the front side of which the semiconductor module 10 is disposed, and a sidewall connection region 22a for connecting an annular sidewall 22 is provided on the back side of the top plate 21. The top plate 21 is rectangular in plan view, and a cooling region 21b with multiple heat sinks 24f disposed along the length direction is provided in the center of the back side. Connecting regions 21c and 21d are respectively provided on both sides of the cooling region 21b along the width direction. The sidewall connection region 22a is annular on the back side of the top plate 21, including the cooling region 21b and the connecting regions 21c and 21d. The thickness T2 of the cooling region 21b of the top plate 21 is thinner than the outer edge thickness T1 of the outer edge regions 21e and 21f of the top plate 21, which are located further outward than the sidewall connection region 22a. Therefore, the distance from the front of the cooling area 21b of the top plate 21 to the multiple heat sinks 24f is shortened. Furthermore, heat from the semiconductor module 10 is easily conducted to the multiple heat sinks 24f, improving the cooling capacity of the refrigerant. Thus, it is possible to prevent a decrease in the reliability of the semiconductor device 1.

[0113] In such a cooling device 20, by reducing the thickness of the connecting regions 21c and 21d of the top plate 21, the cooling performance of the cooling device 20 can be further improved, and the reliability reduction of the semiconductor device 1 can be suppressed. Hereinafter, a modified example of the thickness of the connecting regions 21c and 21d of the top plate 21 will be described. It should be noted that the semiconductor device 1 described in the modified example has the same structure as the semiconductor device 1 already described. However, only the thickness of the connecting regions 21c and 21d of the top plate 21 of the cooling device 20 is different. In the description of the modified example, only the changed parts will be described.

[0114] It should be noted that the aforementioned cooling device 20 integrally comprises a top plate 21, a side wall 22 connected annularly to the back of the top plate 21, and a bottom plate 23 opposite to the top plate 21 and connected to the back of the side wall 22, forming a single unit. The cooling device 20 may not necessarily have this structure. Utilizing... Figure 6 Another example of the cooling device 20 will be described. Figure 6 This is a cross-sectional view of another cooling device included in the semiconductor device of the first embodiment. It should be noted that... Figure 6 This is a cross-sectional view of the cooling device 120, and... Figure 4 The corresponding sectional view.

[0115] The cooling device 120 also includes a top plate 21, a side wall 22 annularly connected to the back of the top plate 21, and a bottom plate 23 opposite to the top plate 21 and connected to the back of the side wall 22. In the case of the cooling device 120, the side wall 22 and the bottom plate 23 are integrally formed separately. The cooling device 120 cools by... Figures 2-4The top plate 21 described herein is constructed by separately mounting a bottom plate 23 with sidewalls 22. It should be noted that when the bottom plate 23 with sidewalls 22 is mounted on the top plate 21, the sidewalls 22 are mounted on the sidewall connection regions 22a of the outer edge regions 21e and 21f of the top plate 21, connecting regions 21c and 21d. The sidewall connection regions 22a are located over the entire area where the annular sidewalls 22 connect to the back of the top plate 21. Therefore, when viewed from above, the sidewall connection regions 22a and the sidewalls 22 of the top plate 21 correspond to the same position.

[0116] For example, a semiconductor device 1 including such a cooling device 120 is shipped with a semiconductor module 10 bonded to a top plate 21 having a plurality of heat sinks 24f. At the destination, a bottom plate 23 having sidewalls 22 is mounted on the top plate 21 to which the semiconductor module 10 is bonded. At this time, the sidewalls 22 are connected to the sidewall connection area 22a of the top plate 21. Thus, a semiconductor device 1 including the cooling device 120 is obtained.

[0117] Hereinafter, a variation of the cooling device 20 included in the semiconductor device 1 of the first embodiment will be described. The cooling device 20 will be used as an example in this description. Furthermore, this variation can also be applied to other applications. Figure 6 The cooling device 120 shown can achieve the same effect.

[0118] [Variation Example 1-1]

[0119] use Figure 7 and Figure 8 The cooling device 20 of modified example 1-1 will be described. Figure 7 This is a cross-sectional view of the main part of the cooling device included in the semiconductor device of the first embodiment, variant 1-1. Figure 8 This is an enlarged cross-sectional view of the main part of the cooling device included in the semiconductor device of the first embodiment, variant 1-1. It should be noted that... Figure 7 Magnification Figure 4 Near the connected region 21c of the top plate 21, Figure 8 Further enlargement indicates Figure 7 Furthermore, in subsequent variations, the connected region 21c of the top plate 21 will be described, while the description of the connected region 21d will be omitted. The structure of the connected region 21c can also be applied to the connected region 21d of the top plate 21.

[0120] In Modification 1-1, in the thickness of the connecting region 21c of the top plate 21, the outer edge region side 21c2 on the outer edge region 21e side is thicker than the cooling region side 21c1 on the cooling region 21b side. The thickness of the outer edge region side 21c2 of the top plate 21 is the same as the thickness T1 of the outer edge region 21e. The thickness of the cooling region side 21c1 of the top plate 21 is the same as the thickness T2 of the cooling region 21b.

[0121] The outer edge region side 21c2 of the top plate 21 is connected to the cooling region side 21c1 via a step portion 21g. Furthermore, the step portion 21g is connected at an angle. In this case, the angle relative to the front (XY plane) of the connecting region 21c of the top plate 21 is preferably 10 degrees or more and 45 degrees or less, more preferably 20 degrees or more and 30 degrees or less. As the plate moves from the cooling region 21b towards the outer edge region 21e, the thickness of the connecting region 21c of the top plate 21 increases from the thickness T2 of the cooling region side 21c1 via the step portion 21g to the thickness T1 of the outer edge region side 21c2. On the back side of the top plate 21, a step portion 21g is formed with a height (length in the Z direction) obtained by subtracting the thickness T2 of the cooling region side 21c1 from the thickness T1 of the outer edge region side 21c2. The height (T1-T2) of the step portion 21g can be 0.4 times or more and 0.6 times or less of the thickness T1 of the outer edge region side portion 21c2. For example, the height (T1-T2) of the step portion 21g can be 0.8 mm or more and 3.2 mm or less. The length of the step portion 21g (length in the direction parallel to the front of the top plate 21 and length in the X direction) can be 1.0 times or more and 5.0 times or less of the height of the step portion 21g. More preferably, it is 1.7 times or more and 2.8 times or less.

[0122] exist Figure 4 In the connecting portion 24b of the cooling device 20 shown, the top plate 21 and the side wall 22 are joined at approximately right angles. Refrigerant flowing through such a connecting portion 24b may become trapped at this corner. If the refrigerant remains in a predetermined location within the cooling device 20, corrosion at the trapped location increases the likelihood of perforation. In particular, since the thickness T2 of the connecting region 21c of the top plate 21 is thinner than the thickness T1 of the outer edge region 21e, the time until corrosion and perforation are considered shorter.

[0123] In Modification 1-1, the outer edge region side 21c2 on the outer edge region 21e side is thicker than the cooling region side 21c1 on the cooling region 21b side in terms of the thickness of the connecting region 21c of the top plate 21. Therefore, even if refrigerant remains in the connection portion of the connecting region 21c of the top plate 21 where it connects to the sidewall 22, the time until it becomes porous due to corrosion can be extended. That is, it is less likely to create a hole in the connection portion of the connecting region 21c of the top plate 21 where it connects to the sidewall 22.

[0124] like Figure 7 As shown, in a side view, the intersection of the top plate 21 and the side wall 22 is designated as intersection point O; the intersection of the outer edge region side portion 21c2 and the step portion 21g is designated as intersection point D; the intersection of the cooling region side portion 21c1 and the step portion 21g is designated as intersection point E; the position of the top plate 21 corresponding to the end of the outlet 23b (or inlet 23a) near the outer edge region 21e (or outer edge region 21f) is designated as position P; and the position of the top plate 21 corresponding to the end of the outlet 23b (or inlet 23a) near the cooling region 21b is designated as position Q. Figure 7 As shown, the length R of the outer edge region side portion 21c2 from the intersection point O to the intersection point D of the top plate 21 and the side wall 22 is preferably the same as or greater than the thickness T1 of the outer edge region 21e of the top plate 21. Therefore, the intersection point D of the outer edge region side portion 21c2 can reach from the side wall 22 to position P. In addition, the intersection point E of the cooling region side portion 21c1 can also be located between position P and position Q corresponding to the outlet 23b (or inlet 23a). In this way, a portion of the step portion 21g enters the position corresponding to the outlet 23b (or inlet 23a), which enables good flow of refrigerant between the outlet 23b (or inlet 23a) and the cooling region 21b. On the other hand, as described above, by making the thickness T2 of the connecting region 21c and the cooling region 21b of the top plate 21 thinner than the thickness T1 of the outer edge region 21e of the top plate 21, the pressure loss of the refrigerant flowing in the cooling section 24a and the connecting sections 24b, 24c is reduced. Therefore, in the top plate 21, the step portion 21g can also be set at the edge of the side wall 22 to maintain the range of the cooling region side portion 21c1 as long as possible.

[0125] Furthermore, the connection between the outer edge side portion 21c2 and the step portion 21g can also be as follows: Figure 8 It is chamfered with an R-shape as shown. It should be noted that... Figure 8 The diagram shows a case where the connection point from the step portion 21g to the outer edge region side portion 21c2 and the step portion 21g is chamfered with an radius (R). Therefore, in the top plate 21, the outer edge region side portion 21c2, located at the edge of the sidewall 22, forms an R-surface at its connection point with the step portion 21g, thereby maintaining reduced pressure loss for the refrigerant flowing in the connecting portion 24b and minimizing the need for openings in the connecting portion 24b.

[0126] Therefore, in the cooling device 20 of Modified Example 1-1, it is possible to... Figure 4 The cooling device 20 also improves cooling performance and further suppresses the decrease in the reliability of the cooling device 20.

[0127] [Variations 1-2]

[0128] use Figure 9 The cooling device 20 of modified examples 1-2 will be described. Figure 9 This is a cross-sectional view of the main part of the cooling device included in the semiconductor device of the first embodiment, variations 1-2. It should be noted that... Figure 9 Magnification Figure 4 Near the connected region 21c of the top plate 21.

[0129] Modification 1-2 is the case in Modification 1-1 where the step portion 21g in the top plate 21 is formed near the cooling region 21b. That is, the outer edge region side portion 21c2 of the top plate 21 extends further toward the cooling region 21b than the outer edge region side portion 21c2 of Modification 1-1. Furthermore, the cooling region side portion 21c1 of the top plate 21 is shorter than the cooling region side portion 21c1 of Modification 1-1.

[0130] exist Figure 4 and Figure 7 In the cooling device 20, foreign objects such as debris, air, and air bubbles may sometimes enter. If such foreign objects are present in the cooling device 20, they will hinder the flow of refrigerant, potentially reducing the flow rate and cooling performance.

[0131] In modifications 1-2, the outer edge region side portion 21c2 of the top plate 21 extends further toward the cooling region 21b than the outer edge region side portion 21c2 of modification 1-1. Consequently, the cross-sectional area of ​​the connecting portion 24b is greater than that of the cooling region 21b. Figure 4 and Figure 7 The cooling device 20 is narrow. That is, the flow rate of the refrigerant flowing through such a connecting portion 24b increases, and the pressure of the refrigerant flow increases. Therefore, foreign matter present in the connecting portion 24b is easily discharged from the outlet 23b along with the refrigerant. Furthermore, in modifications 1-2, the thickness near the side wall 22 of the top plate 21 is also set to T1. As a result, even if the refrigerant is retained at the connection between the connecting region 21c of the top plate 21 and the side wall 22, it is not easy to make an opening.

[0132] and Figure 7 Similarly, as Figure 9As shown, in a side view, the intersection of the top plate 21 and the side wall 22 is designated as intersection point O, the intersection of the outer edge region side portion 21c2 and the step portion 21g is designated as intersection point D, the intersection of the cooling region side portion 21c1 and the step portion 21g is designated as intersection point E, the position corresponding to the end of the top plate 21 on the side of the outer edge region 21e (or the side of the outer edge region 21f) of the outlet 23b (or the inlet 23a) is designated as position P, and the position corresponding to the end of the top plate 21 on the side of the outlet 23b (or the inlet 23a) on the side of the cooling region 21b is designated as position Q. In cases where the cooling region side portion 21c1 (relative to the X direction) is too short and the step portion 21g is too close to the cooling region 21b of the top plate 21, the thermal conductivity of the cooling region 21b of the top plate 21 may decrease. However, in this modified example 1-2, as... Figure 9 As shown, for the cooling region side 21c1, the thickness T2 of the cooling region 21b of the top plate 21 is the same as or longer than the thickness T2, starting from the cooling region 21b. In the top plate 21, for example, the intersection point E of the cooling region side 21c1 can reach from the cooling region 21b to position Q. Assuming that the cooling region side 21c1 exceeds position Q, the top plate 21 on the outlet 23b becomes thickness T2, and there is a possibility that the flow rate of the refrigerant flowing through the outlet 23b is not sufficiently increased. Therefore, by making the intersection point E of the cooling region side 21c1 of the top plate 21 reach from the cooling region 21b to position Q, the flow rate of the refrigerant can be reliably increased. Furthermore, the intersection point D of the outer edge region side 21c2 can be located between position P and position Q corresponding to the outlet 23b (or inlet 23a). In this way, a portion of the step portion 21g enters the position corresponding to the outlet 23b (or inlet 23a), which enables better flow of refrigerant between the outlet 23b (or inlet 23a) and the cooling zone 21b.

[0133] Therefore, in the cooling device 20 of the modified examples 1-2, it is not easy to make a hole in the connecting part 24b, foreign objects can be discharged, the cooling performance can be improved, and the reliability of the cooling device 20 can be further suppressed.

[0134] [Variations 1-3]

[0135] use Figure 10 The cooling device 20 of the modified examples 1-3 will be described. Figure 10 This is a cross-sectional view of the main part of the cooling device included in the semiconductor device of the first embodiment's variations 1-3. It should be noted that... Figure 10 Magnification Figure 4 Near the connected region 21c of the top plate 21. Furthermore, in Figure 10 In, also with Figure 6Similarly, when viewed from the side, the intersection of the top plate 21 and the side wall 22 is designated as intersection point O, the position of the top plate 21 corresponding to the end of the outlet 23b (or inlet 23a) near the outer edge region 21e (or outer edge region 21f) is designated as position P, and the position of the top plate 21 corresponding to the end of the outlet 23b (or inlet 23a) near the cooling region 21b is designated as position Q.

[0136] In the cooling device 20 of variations 1-3, two stepped portions 21g1 and 21g2 are formed in the connecting region 21c of the top plate 21. That is, in the cooling device 20 of variations 1-3, in the connecting region 21c of the top plate 21, as it moves from the cooling region 21b to the outer edge region 21e, starting from the cooling region side 21c1, each time a stepped portion 21g1 or 21g2 is formed, the middle portion 21c3 and the outer edge region side portion 21c2 become thicker. The cooling region side portion 21c1 of the top plate 21 has a thickness T2, and the outer edge region side portion 21c2 has a thickness T1. The thickness of the middle portion 21c3 is thicker than the thickness T2 and thinner than the thickness T1. The intersection point of the outer edge region side portion 21c2 and the step portion 21g2 located on the side closest to the outer edge region 21e is set as intersection point D, and the intersection point of the cooling region side portion 21c1 and the step portion 21g1 located on the side closest to the cooling region 21b is set as intersection point E.

[0137] In the cooling device 20 of such modifications 1-3, similarly to that of modification 1-1, it is less prone to developing holes due to corrosion. Furthermore, compared to the cooling device 20 of modification 1-1, the cross-sectional area of ​​the connecting portion 24b in the cooling device 20 of modifications 1-3 is smaller. Therefore, in the cooling device 20 of modifications 1-3, compared to the cooling device 20 of modification 1-1, internal foreign matter can be eliminated, and cooling performance can be improved.

[0138] Furthermore, in the cooling device 20 of modifications 1-3, the cross-sectional area of ​​the connecting portion 24b is larger than that of the cooling device 20 of modifications 1-2. Therefore, in the cooling device 20 of modifications 1-3, compared with the cooling device 20 of modifications 1-2, the pressure loss of the refrigerant flowing in the connecting portion 24b can be reduced, and the cooling performance can be improved.

[0139] Therefore, in the cooling device 20 of the modified examples 1-3, it is not easy to open due to corrosion, foreign matter can be discharged, pressure loss of refrigerant can be reduced, cooling performance can be improved, and the reliability of the cooling device 20 can be further suppressed.

[0140] It should be noted that in the cooling device 20 of variations 1-3, the middle portion 21c3 of the top plate 21 preferably corresponds to the outlet 23b (or inlet 23a) when viewed from the side. That is, at least a portion of the middle portion 21c3 may be located between position P and position Q corresponding to the outlet 23b (or inlet 23a). The stepped portion 21g1 of the top plate 21 preferably corresponds to a position closer to the cooling region 21b than the outlet 23b when viewed from the side. That is, in the top plate 21, the intersection point E of the stepped portion 21g1 is located closer to the cooling region 21b than the position Q corresponding to the end of the outlet 23b on the cooling region 21b side when viewed from the side. Furthermore, the intersection point D of the stepped portion 21g2 is preferably located closer to the outer edge region 21e than the position P corresponding to the end of the outlet 23b on the outer edge region 21e side when viewed from the side. Therefore, compared with the case of Modification 1-1, the flow rate of the refrigerant flowing at the outlet 23b can be reliably increased.

[0141] Furthermore, in variations 1-3, it is illustrated that two stepped portions 21g1 and 21g2 are provided in the connecting region 21c of the top plate 21, wherein each stepped portion 21g1 and 21g2 has three parts with different heights. However, this is not a limitation; the number of stepped portions may also be three or more, wherein each stepped portion has four or more parts with different heights.

[0142] [Second Implementation]

[0143] In the second embodiment, using Figure 11 and Figure 12 The semiconductor device 1, which is disposed on the top plate 21 with semiconductor module 10 over cooling area 21b provided with heat sink 24f, will be described. Figure 11 This is a cross-sectional view of the cooling device included in the semiconductor device of the second embodiment. Figure 12 This is a top view of the cooling device included in the semiconductor device of the second embodiment. It should be noted that, utilizing... Figure 6 The semiconductor device 1 of the second embodiment will be described using the cooling device 120 described in the text. It is also possible to... Figure 4 The cooling device 20 described herein is also applied to the semiconductor device 1 of the second embodiment.

[0144] To achieve miniaturization, the semiconductor device 1 maintains the size of the semiconductor module 10 while preferentially reducing the size of the cooling region 21b. If the cooling region 21b, where the heat sink 24f is located, is reduced in size, although the semiconductor module 10 is positioned on the cooling region 21b, a portion will extend beyond the cooling region 21b. That is, the heat sink 24f will not be present directly below the area of ​​the semiconductor module 10 extending beyond the cooling region 21b. Furthermore, during thermal cycling tests, the semiconductor device 1 experiences thermal stress due to the difference in the coefficients of linear expansion between the semiconductor module 10 (semiconductor chip 12 and insulating circuit board 11) and the cooling device 120 (top plate 21). It should be noted that the coefficient of linear expansion of the top plate 21 (e.g., aluminum) is 2.4 × 10⁻⁶. -5 At approximately ℃, the coefficient of linear expansion of sealing components (such as epoxy resin) is 1.4 × 10⁻⁶. -5 Around / ℃.

[0145] When there is no heat sink 24f directly below the extended cooling region 21b (extended regions 21h, 21i) of the semiconductor module 10, the amount of deformation (change) caused by thermal stress in the semiconductor device 1 (cooling device 120) increases compared to the case where the heat sink 24f is present. As a result, when the cooling device 120 is sealed with a sealing member, peeling of the sealing member may occur starting from near the insulating circuit board 11. This leads to a decrease in the reliability of the semiconductor device 1.

[0146] Therefore, in the cooling device 120 of the semiconductor device 1, a buffer plate 25 is provided on the back side of the top plate 21 (the side opposite to the bottom plate 23). The buffer plate 25 is formed along the width direction of the top plate 21. That is, the outer end (outer edge regions 21e, 21f side) of the buffer plate 25 is located on the sidewall 22 of the top plate 21, and the inner end E1 is located further inward than the outer edge E2 of the insulating circuit board 11 (protrusion regions 21h, 21i). In this way, by providing the buffer plate 25 in the protrusion regions 21h, 21i of the semiconductor module 10 extending from the cooling region 21b, the thermal stress generated in the cooling device 120 can be mitigated, and the deformation of the cooling device 120 (semiconductor device 1) can be suppressed.

[0147] It should be noted that the buffer plate 25 is disposed in such protruding regions 21h, 21i when the protruding regions 21h, 21i extending from the cooling region 21b of the semiconductor module 10 are not provided with heat sinks 24f. In the second embodiment, as Figure 11 and Figure 12As shown, the semiconductor module 10 extends from both edges (in the ±X direction) of the cooling region 21b. Therefore, the buffer plate 25 is provided on the extended regions 21h and 21i on both sides of the cooling region 21b. When the semiconductor module 10 extends only from one edge (in the ±X direction) of the cooling region 21b, the buffer plate 25 is provided on the top plate 21 corresponding to the extended region on that one side.

[0148] The end E1 of the buffer plate 25 only needs to be located within the protruding regions 21h and 21i, which are further inward than the outer edge E2 of the insulating circuit board 11, or it can be in contact with the outermost heat sink 24f. Here, the case where the end E1 of the buffer plate 25 is within the protruding regions 21h and 21i and separated from the outermost heat sink 24f (outward) is shown. However, the end E1 of the buffer plate 25 will not enter a position further inward than the outermost heat sink 24f (protruding regions 21h and 21i). If the end E1 of the buffer plate 25 enters a position further inward than the outermost heat sink 24f, the cooling performance of the cooling region 21b will be reduced.

[0149] Here, it is shown that the stacking thickness T3 of the buffer plate 25 and the top plate 21 of the connecting region 21c are the same as the thickness T1. By increasing the stacking thickness T3 (the thickness of the buffer plate 25), the thermal stress generated in the cooling device 120 can be further mitigated. However, if the thickness of the buffer plate 25 is too thick, the pressure loss of the refrigerant flowing in the cooling section 24a and the connecting sections 24b, 24c increases. Furthermore, the heat dissipation from the front of the top plate 21 to the refrigerant flowing in the connecting regions 21c, 21d is also reduced. Therefore, the thickness of the buffer plate 25 should be selected such that the stacking thickness T3 is at most the same as the thickness T1.

[0150] In the second embodiment, an example is shown where the buffer plate 25 is separately installed on the top plate 21. The buffer plate 25 may also be integrally formed with the communicating regions 21c and 21d of the top plate 21.

[0151] Hereinafter, a variation of the cooling plate 25 included in the cooling device 120 of the semiconductor device 1 according to the second embodiment will be described. The cooling device 120 will also be used as an example for this description. Furthermore, this variation can be similarly applied to other devices. Figure 4 The cooling device 20 shown can achieve the same effect.

[0152] [Variation Example 2-1]

[0153] use Figure 13 and Figure 14 The semiconductor device 1 of Modified Example 2-1 will be described. Figure 13 This is a cross-sectional view of the cooling device included in the semiconductor device of the second embodiment, variant 2-1. Figure 14 This is a top view of the cooling device included in the semiconductor device of the second embodiment, variant 2-1.

[0154] As described above, the buffer plate 25 is disposed on the back side of the top plate 21 from the side wall 22 to the protruding regions 21h and 21i of the semiconductor module 10 extending from the cooling region 21b. This mitigates the thermal stress generated in the cooling device 120 and suppresses deformation of the cooling device 120 (semiconductor device 1). That is, the buffer plate 25 only needs to be formed on the back side of the top plate 21 at least corresponding to the protruding regions 21h and 21i of the semiconductor module 10 extending from the cooling region 21b. For example, as... Figure 13 and Figure 14 As shown, the buffer plate 25 is formed on the back side of the top plate 21 within the area corresponding to the protruding regions 21h and 21i. In this case, the thermal stress generated in the cooling device 120 can also be mitigated, and deformation of the cooling device 120 (semiconductor device 1) can be suppressed. Furthermore, the buffer plate 25 is not provided on the back side of the top plate 21 between the outer edge E2 of the insulating circuit board 11 and the sidewall 22. Therefore, the increase in pressure loss of the refrigerant flowing in the cooling section 24a and the connecting sections 24b and 24c can be suppressed. Furthermore, the decrease in heat dissipation from the front side of the top plate 21 to the refrigerant flowing in the connecting regions 21c and 21d can be suppressed.

[0155] Furthermore, the corners of the base plate 23 side of the buffer plate 25 can also be chamfered. This facilitates the flow of refrigerant between the cooling section 24a and the connecting sections 24b and 24c. In other words, by maintaining a reduced refrigerant pressure loss, the refrigerant's residence time due to the buffer plate 25 is reduced, and even if refrigerant does remain, the time until it corrodes and causes perforation can be extended. That is, it is less likely to create perforations at the connection between the top plate 21 and the buffer plate 25.

[0156] It should be noted that in Modification 2-1, the thickness of the connected regions 21c and 21d of the top plate 21 can also be varied as described in Modifications 1-1, 1-2 and 1-3.

[0157] [Variation Example 2-2]

[0158] use Figure 15 The semiconductor device 1 of Modified Example 2-2 will be described. Figure 15 This is a cross-sectional view of the main part of the cooling device included in the semiconductor device of the second embodiment, variant 2-2. It should be noted that... Figure 15 With variation example 1-1 ( Figure 7 ) and variations 1-2 ( Figure 9 Correspondingly, the enlarged representation includes the area surrounding the buffer plate 25.

[0159] In Modification 2-2, the end of the buffer plate 25 on the outer edge region 21e side is located on the sidewall 22 of the back side of the top plate 21. The end E1 of the buffer plate 25 is located within the protruding region 21h. Furthermore, in Modification 2-2, the thickness of the buffer plate 25 is different from that of the top plate 21 in Modification 1-2. That is, in Modification 2-2, the buffer plate 25 is configured such that, in the stacked thickness of the top plate 21 and the buffer plate 25 in the connecting region 21c, the outer edge region side 21c2 on the outer edge region 21e side is thicker than the cooling region side 21c1 on the cooling region 21b side. The stacked thickness of the top plate 21 and the buffer plate 25 with the outer edge region side 21c2 is the same as the thickness T1 of the outer edge region 21e. The thickness of the cooling region side 21c1 of the top plate 21 is the same as the thickness T2 of the cooling region 21b.

[0160] The outer edge region side 21c2 of the buffer plate 25 is connected to the cooling region side 21c1 via a step portion 21g. Furthermore, the step portion 21g is connected at an angle. In this case, the angle relative to the front (XY plane) of the connecting region 21c of the buffer plate 25 is preferably 10 degrees or more and 45 degrees or less, more preferably 20 degrees or more and 30 degrees or less. As the material moves from the cooling region 21b towards the outer edge region 21e, the stacking thickness of the top plate 21 and the connecting region 21c of the buffer plate 25 increases from the thickness T2 of the cooling region side 21c1 via the step portion 21g to the thickness T1 of the outer edge region side 21c2. Similar to Modified Example 1-1, the step portion 21g is formed with a height (length in the Z direction) obtained by subtracting the thickness T2 of the cooling region side 21c1 from the thickness T1 of the outer edge region side 21c2. In modified example 2-2, the height (T1-T2) of the step portion 21g can be 0.4 times or more and 0.6 times or less of the thickness T1 of the outer edge region side portion 21c2. For example, the height (T1-T2) of the step portion 21g can be 0.8 mm or more and 3.2 mm or less. The length of the step portion 21g (length in the direction parallel to the front of the top plate 21 and length in the X direction) can be 1.0 times or more and 5.0 times or less of the height of the step portion 21g. More preferably, it is 1.7 times or more and 2.8 times or less.

[0161] In Modification 2-2, by setting the top plate 21 and the buffer plate 25 to such thicknesses, it is similar to Modification 1-1 ( Figure 7 Similarly, even if the refrigerant remains in the connection between the communication area 21c of the buffer plate 25 and the top plate 21 and the side wall 22, the time until it becomes porous due to corrosion can be extended. That is, it is not easy to create a hole in the connection between the communication area 21c of the buffer plate 25 and the top plate 21 and the side wall 22.

[0162] Furthermore, in Modification 2-2, it is also similar to Modification 1-1 ( Figure 7Similarly, preferably, the length R of the outer edge region side portion 21c2 from the intersection point O of the top plate 21 and the side wall 22 to the intersection point D is the same as or greater than the thickness T1 of the outer edge region 21e of the top plate 21 (here, the case where the length R is greater than or greater than the thickness T1 is shown). Therefore, the intersection point D of the outer edge region side portion 21c2 can reach from the side wall 22 to the position P.

[0163] Furthermore, in Modification 2-2, it is also similar to Modification 1-2 ( Figure 9 Similarly, in the top plate 21, for example, the end E1 of the buffer plate 25 can reach between the cooling zone 21b and the outer edge E2. If the cooling zone side 21c1 exceeds position Q, the top plate 21 on the outlet 23b becomes thinner than the thickness T1, resulting in insufficient increase in the refrigerant flow rate at the outlet 23b. Therefore, by making the end E1 of the buffer plate 25 reach between the cooling zone 21b and the outer edge E2, the refrigerant flow rate can be reliably increased.

[0164] Furthermore, in Modification 2-2, the connection between the outer edge region side portion 21c2 and the stepped portion 21g can also be chamfered (R-shaped). By chamfering the connection portion (R-shaped), the cross-sectional area of ​​the connecting portion 24b can be maintained as large as possible while maintaining the length R. Therefore, in the top plate 21, the outer edge region side portion 21c2 is located at the edge of the side wall 22, and an R-shaped surface is formed at the connection with the stepped portion 21g, thereby maintaining and reducing the pressure loss of the refrigerant flowing in the connecting portion 24b, and making it less likely to have an opening in the connecting portion 24b.

[0165] Furthermore, in Modification 2-2, although the illustration is omitted, it can be compared with Modification 1-2 ( Figure 9 Similarly, in the buffer plate 25, a stepped portion 21g is formed near the cooling region 21b. That is, the outer edge region side portion 21c2 of the buffer plate 25 can also be larger than... Figure 15 The outer edge region side 21c2 extends further towards the cooling region 21b. Furthermore, the cooling region side 21c1 of the top plate 21 can be larger than... Figure 15 The cooling area side 21c1 is shorter. Therefore, the cross-sectional area of ​​the connecting portion 24b is smaller than... Figure 15 The cooling device 120 is small. That is, the flow rate of the refrigerant flowing through such a connecting portion 24b increases, and the pressure of the refrigerant flow increases. Therefore, foreign matter present in the connecting portion 24b is easily discharged from the outlet 23b along with the refrigerant. Furthermore, in this case, the sidewalls 22 of the top plate 21 and the buffer plate 25 are also provided with a thickness T1. As a result, even if the refrigerant is retained in the connection portion between the connecting area 21c of the buffer plate 25 and the top plate 21 and the sidewall 22, it is not easy to make a hole.

[0166] Furthermore, if the cooling region side portion 21c1 (relative to the X direction) is too short and the step portion 21g is too close to the cooling region 21b of the top plate 21, the thermal conductivity of the cooling region 21b of the top plate 21 may decrease. However, if the step portion 21g in the buffer plate 25 is formed near the cooling region 21b, the cooling region side portion 21c1, starting from the cooling region 21b, has the same thickness T2 as or longer than the thickness T2 of the cooling region 21b of the top plate 21. In the top plate 21, for example, the end portion E1 of the buffer plate 25 can reach from the cooling region 21b to position Q. Assuming the cooling region side portion 21c1 exceeds position Q, the top plate 21 on the outlet 23b becomes thickness T2, and there is a possibility that the refrigerant flow rate flowing through the outlet 23b is not sufficiently increased. Therefore, by making the end portion E1 of the buffer plate 25 reach from the cooling region 21b to position Q, the refrigerant flow rate can be reliably increased. Furthermore, the intersection point D of the outer edge region side portion 21c2 can be located between position P and position Q corresponding to the outlet 23b (or inlet 23a). In this way, a portion of the step portion 21g enters the position corresponding to the outlet 23b (or inlet 23a), which can improve the flow of refrigerant between the outlet 23b (or inlet 23a) and the cooling region 21b.

[0167] Therefore, in the cooling device 120 of modified example 2-2, with Figure 11 Compared to the cooling device 120, it can improve cooling performance and further suppress the decrease in the reliability of the cooling device 120.

[0168] [Variations 2-3]

[0169] use Figure 16 The semiconductor device 1 of variations 2-3 will be described. Figure 16 This is a cross-sectional view of the main part of the cooling device included in the semiconductor device of the second embodiment, variations 2-3. It should be noted that... Figure 16 With variations 1-3 ( Figure 10 Correspondingly, the enlarged representation includes the area surrounding the buffer plate 25.

[0170] In variations 2-3, the results are similar to those in variations 1-3. Figure 10 Similarly, the thickness of the buffer plate 25 is different from that of the top plate 21 of the original plate. That is, in modified examples 2-3, the thickness is different from that of modified examples 1-3. Figure 10Similarly, in the case where two stepped portions 21g1 and 21g2 are formed in the connecting region 21c of the top plate 21 and the buffer plate 25, in the cooling device 120 of modified examples 2-3, as the cooling region 21c of the top plate 21 and the buffer plate 25 moves from the cooling region 21b to the outer edge region 21e, starting from the cooling region side 21c1, each time a stepped portion 21g1 or 21g2 is formed, the middle portion 21c3 and the outer edge region side 21c2 respectively become thicker. The cooling region side 21c1 of the top plate 21 has a thickness T2, and the outer edge region side 21c2 has a thickness T1. The thickness of the middle portion 21c3 is thicker than the thickness T2 and thinner than the thickness T1. The intersection point of the outer edge region side portion 21c2 and the step portion 21g2 located on the side closest to the outer edge region 21e is set as intersection point D, and the intersection point of the cooling region side portion 21c1 and the step portion 21g1 located on the side closest to the cooling region 21b is set as intersection point E.

[0171] In the cooling device 120 of such modification 2-3, similarly to modification 2-2, it is less prone to pore formation due to corrosion. Furthermore, compared to the cooling device 120 of modification 2-2, the cross-sectional area of ​​the connecting portion 24b in the cooling device 120 of modification 2-3 is smaller. Therefore, compared to the cooling device 120 of modification 2-2, the cooling device 120 of modification 2-3 can remove internal foreign matter and improve cooling performance.

[0172] Furthermore, in the cooling device 20 of Modified Example 2-3, compared to the case in the cooling device 120 of Modified Example 2-2 where the step portion 21g is formed near the cooling region 21b, the cross-sectional area of ​​the connecting portion 24b is increased. Therefore, in the cooling device 120 of Modified Example 2-3, compared to the case of Modified Example 2-2, the pressure loss of the refrigerant flowing in the connecting portion 24b can be reduced, and the cooling performance can be improved.

[0173] Therefore, in the cooling device 120 of the modified examples 2-3, it is not easy to open due to corrosion, foreign matter can be discharged, pressure loss of refrigerant can be reduced, cooling performance can be improved, and the reliability of the cooling device 120 can be further suppressed.

[0174] It should be noted that in the cooling device 120 of Modification 2-3, it is also preferable that the middle portion 21c3 of the top plate 21 corresponds to the outlet 23b (or inlet 23a) when viewed from the side. Therefore, compared with the case of Modification 2-2, the flow rate of the refrigerant flowing at the outlet 23b can be reliably increased.

[0175] Furthermore, in variations 2-3, it is illustrated that two stepped portions 21g1 and 21g2 are provided in the connecting region 21c of the buffer plate 25, wherein each stepped portion 21g1 and 21g2 has three parts with different heights. However, this is not a limitation; the number of stepped portions may also be three or more, wherein each stepped portion has four or more parts with different heights.

[0176] In addition, using Figure 17 The following describes the case of a vehicle, which is an example of a device including the semiconductor device 1 of the first and second embodiments described above. Figure 17 This is a schematic diagram of a vehicle. Vehicle 30 is a vehicle that uses electricity to generate at least a portion of its propulsion. As an example, vehicle 30 is an electric vehicle that generates all its propulsion from an electric drive device such as a motor, or a hybrid vehicle that uses both an electric drive device such as a motor and an internal combustion engine driven by fuel such as gasoline.

[0177] The vehicle 30 is equipped with a control device 31 (external device) for controlling electrically driven equipment such as motors. A semiconductor device 1 is provided in the control device 31. The semiconductor device 1 can control the power supplied to the electrically driven equipment.

[0178] Next, using Figure 18 The equivalent circuit included in semiconductor device 1 will be described. Figure 18 This is a diagram of the equivalent circuit included in the semiconductor device. The semiconductor device 1 of the first and second embodiments functions as a three-phase AC inverter circuit having output terminals U, V, and W, and can be part of an on-board unit that drives the electric motor of the vehicle 30.

[0179] It should be noted that, in Figure 18 The image shows semiconductor chips 12c1 to 12c6 included in semiconductor device 1, which respectively contain... Figure 1 The RC-IGBTs of the semiconductor chips 12a1 to 12a6 and 12b1 to 12b6 shown are functional.

[0180] In semiconductor device 1, semiconductor chips 12c1, 12c2, and 12c3 can form the upper arm, and semiconductor chips 12c4, 12c5, and 12c6 can form the lower arm. A group of semiconductor chips 12c1 and 12c4 can form a branch (W phase). Similarly, a group of semiconductor chips 12c2 and 12c5, and a group of semiconductor chips 12c3 and 12c6 can also form branches (V phase and U phase).

[0181] In semiconductor chip 12c6, the emitter can be electrically connected to input terminal N1, and the collector can be electrically connected to output terminal U. In semiconductor chip 12c3, the emitter can be electrically connected to output terminal U, and the collector can be electrically connected to input terminal P1. Similarly, in semiconductor chips 12c5 and 12c4, the emitter can be electrically connected to input terminals N2 and N3, respectively, and the collector can be electrically connected to output terminals V and W, respectively. Furthermore, in semiconductor chips 12c2 and 12c1, the emitter can be electrically connected to output terminals V and W, respectively, and the collector can be electrically connected to input terminals P2 and P3, respectively.

[0182] Each semiconductor chip 12c1 to 12c6 can alternately switch on and off according to the signal input to the corresponding control terminal. In this embodiment, each semiconductor chip 12c1 to 12c6 can generate heat during switching. Input terminals P1, P2, and P3 can be connected to the positive terminal of an external power supply, input terminals N1, N2, and N3 can be connected to the negative terminal of an external power supply, and output terminals U, V, and W can be connected to a load. Input terminals P1, P2, and P3 can be electrically connected to each other, and other input terminals N1, N2, and N3 can also be electrically connected to each other.

[0183] The above only illustrates the principle of the present invention. Furthermore, those skilled in the art can make various modifications and alterations. The present invention is not limited to the precise structures and application examples shown and described above; all corresponding modifications and equivalents are considered to be within the scope of the present invention based on the appended claims and their equivalents.

Claims

1. A semiconductor device, characterized in that, include: A semiconductor module having a semiconductor chip and an insulating circuit board on which the semiconductor chip is mounted; as well as A cooling device having a top plate on the front of which the semiconductor module is disposed, and a sidewall connection area on the back of the top plate for connecting annular sidewalls. The top plate is rectangular when viewed from above. A cooling area with multiple heat sinks is located along the length of the central portion of the back side. A first connecting area and a second connecting area are respectively located on both sides of the cooling area along its width. The sidewall connection area is arranged in a ring shape on the back side of the top plate, including the cooling area, the first connecting area, and the second connecting area. The thickness of the cooling zone is thinner than the outer edge thickness of the outer edge region of the top plate that is further outward than the sidewall connection region. Regarding the thickness of the first and second connected regions of the top plate, the outer edge region side is thicker than the cooling region side.

2. The semiconductor device according to claim 1, characterized in that, The front surfaces of the top plate form a single plane. On the back side of the top plate, the cooling area is recessed further toward the front side than the outer edge area.

3. The semiconductor device according to claim 1, characterized in that, The thickness of the cooling area side portions of the first and second connected regions is the same as the thickness of the cooling area of ​​the top plate. The thickness of the outer edge region side of the first connected region and the second connected region is the same as the thickness of the outer edge region of the top plate.

4. The semiconductor device according to claim 1, characterized in that, In the first and second connected regions, one or more stepped portions are provided between the cooling region and the outer edge region. As one progresses from the cooling region toward the outer edge region, the thickness of the top plate of the first connecting region and the second connecting region increases once for each step.

5. The semiconductor device according to claim 4, characterized in that, The stepped portion is located at the edge of the sidewall connection area in the top plate.

6. The semiconductor device according to claim 4, characterized in that, The steps are respectively located near the boundary between the cooling area and the first connected area, and near the boundary between the cooling area and the second connected area.

7. The semiconductor device according to claim 1, characterized in that, The cooling device further includes a sidewall connected to the sidewall connection area of ​​the top plate, and a bottom plate opposite the top plate and formed on the back of the sidewall. The top plate, the side wall, and the bottom plate constitute a flow path for refrigerant to flow.

8. The semiconductor device according to claim 7, characterized in that, An inlet is formed in the area of ​​the base plate corresponding to the first communicating region, allowing refrigerant to flow into the flow path section. An outlet is formed in the region of the base plate corresponding to the second communicating region, allowing the refrigerant to flow out from the flow path.

9. The semiconductor device according to claim 8, characterized in that, When viewed from the side, the outer edge region of the first connecting region extends from the sidewall to a position corresponding to the end of the outer edge region of the inlet. The outer edge region of the second connecting region, when viewed from the side, extends from the sidewall to at least the position corresponding to the end of the outer edge region of the outlet.

10. The semiconductor device according to claim 8 or 9, characterized in that, When viewed from the side, the cooling area side of the first connecting region extends from the cooling area to a position corresponding to the end of the inlet on the cooling area side. The cooling area side of the second connecting region, when viewed from the side, extends from the cooling area to a position corresponding to the end of the outlet on the cooling area side.

11. The semiconductor device according to claim 4, characterized in that, The stepped portion is inclined in a manner that connects different heights in the first and second connected regions.

12. The semiconductor device according to claim 11, characterized in that, The angle of inclination of the stepped portion relative to the back of the first and second connecting regions of the top plate is more than 10 degrees and less than 45 degrees.

13. The semiconductor device according to claim 12, characterized in that, The tilt angle is further greater than 20 degrees and less than 30 degrees.

14. The semiconductor device according to any one of claims 11 to 13, characterized in that, The stepped portion and the connecting parts at different heights form an R-surface.

15. The semiconductor device according to claim 1 or 2, characterized in that, The semiconductor module is disposed in the cooling area on the front side of the top plate.

16. The semiconductor device according to claim 15, characterized in that, The width of the cooling region in the width direction is narrower than the width of the insulating circuit board in the width direction. The insulating circuit board is configured on the front side of the top plate to extend from the outer edge of at least one side of the cooling region in the width direction toward at least one of the first connecting region and the second connecting region. A buffer plate is provided on the back side of the top plate within a range corresponding to the portion of the insulating circuit board extending from the cooling area.

17. The semiconductor device according to claim 16, characterized in that, The buffer plate further extends along the width direction on the back side of the top plate to the sidewall connection area.

18. The semiconductor device according to claim 16 or 17, characterized in that, The overall thickness of the combined top plate and the buffer plate is the same as the thickness of the outer edge region of the top plate.

19. The semiconductor device according to claim 17, characterized in that, For the stacking thickness of the top plate and the buffer plate together in at least one region of the first and second connected regions on the side where the insulating circuit board extends, the outer edge region side is thicker than the cooling region side.

20. The semiconductor device according to claim 19, characterized in that, The stack thickness of the cooling region side of at least one of the first and second connected regions on the extended side of the insulating circuit board is the same as the thickness of the cooling region of the top plate. The stacking thickness of the outer edge region side of at least one of the first and second connected regions on the side extending from the insulating circuit board is the same as the thickness of the outer edge region of the top plate.

21. The semiconductor device according to claim 19 or 20, characterized in that, At least one of the first and second connected regions on the extended side of the insulating circuit board has one or more stepped portions provided between the cooling region and the outer edge region. As the material moves from the cooling region toward the outer edge region, the stack thickness increases once for each step.

22. The semiconductor device according to claim 21, characterized in that, The stepped portion is located at the edge of the sidewall connection area in the top plate.

23. The semiconductor device according to claim 21, characterized in that, The stepped portion is respectively disposed near the boundary between at least one of the first connecting region and the second connecting region on the side of the cooling region extending from the insulating circuit board.

24. The semiconductor device according to claim 15, characterized in that, The cooling device further includes a sidewall connected to the sidewall connection area of ​​the top plate, and a bottom plate opposite the top plate and formed on the back of the sidewall. The top plate, the side wall, and the bottom plate constitute a flow path for refrigerant to flow.

25. The semiconductor device according to claim 24, characterized in that, An inlet is formed in the area of ​​the base plate corresponding to the first communicating region, allowing refrigerant to flow into the flow path section. An outlet is formed in the region of the base plate corresponding to the second communicating region, allowing the refrigerant to flow out from the flow path.

26. The semiconductor device according to claim 25, characterized in that, When viewed from the side, the outer edge region side of at least one of the first and second connected regions on the side of the extended side of the insulating circuit board extends from the sidewall to a position corresponding to the end of the outer edge region side of the inlet or outlet.

27. The semiconductor device according to claim 25 or 26, characterized in that, The cooling region side of at least one of the first and second connected regions on the side of the extended portion of the insulating circuit board extends from the cooling region to a position corresponding to the end of the inlet or outlet near the cooling region side when viewed from the side.

28. The semiconductor device according to claim 21, characterized in that, The stepped portion is inclined in at least one region of the first and second connected regions on the side of the insulating circuit board that extends outward, in a manner that connects different heights.

29. The semiconductor device according to claim 7 or 24, characterized in that, When viewed from above, the top plate and the bottom plate have the same shape.

30. The semiconductor device according to claim 7 or 24, characterized in that, Fastening holes are formed at least at each of the four corners of the outer edge region of the top plate.

31. The semiconductor device according to claim 30, characterized in that, The semiconductor devices are each formed with a fastening reinforcement, which is formed around the fastening hole on the back side of the top plate and connected to the front side of the bottom plate.

32. The semiconductor device according to claim 1, characterized in that, The thickness of the cooling zone of the top plate is more than 40% and less than 60% of the thickness of the outer edge zone.

33. A vehicle, characterized in that, The semiconductor device includes any one of claims 1 to 32.

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