Semiconductor equipment

Abstract

To provide a semiconductor device in which the back surface of a cooling device is hardly damaged.SOLUTION: An outer frame 21 (outer walls 21a, 21c) of a housing 20 of a semiconductor device 1 includes spacer portions 21a2, 21c2 projecting from the bottom surface of a cooling bottom plate 33 to the opposite side of a semiconductor chip. For example, when the semiconductor device 1 is placed on an arbitrary mounting surface, the back surface of a cooling device 3 (bottom surface of the cooling bottom plate 33) is spaced from the mounting surface by the spacers 21a2, 21c2. Therefore, the bottom surface 33d of the cooling bottom plate 33 does not directly touch the mounting surface and is less likely to be damaged. Sealing between a water pipe attached to the cooling device 3 of the semiconductor device 1 and an inlet and an outlet 33b of the cooling bottom plate 33 is maintained.SELECTED DRAWING: Figure 3

Description

TECHNICAL FIELD

[0001] The present invention relates to a semiconductor device. BACKGROUND ART

[0002] A semiconductor device includes a semiconductor module and a cooling device. The semiconductor module includes a power semiconductor element and is mounted on the cooling device. A coolant flows inside the cooling device. Thereby, the cooling device cools the heat-generating semiconductor module and maintains the reliability of the semiconductor module.

[0003] The cooling device is formed with opening holes for inflow and outflow of the coolant respectively on its back surface. Further, a water distribution pipe is aligned with the opening hole, and the water distribution pipe is installed with a sealing member (for example, an O-ring or rubber packing) sandwiched in a region around the opening hole (seal region) (see, for example, Patent Document 1). PRIOR ART DOCUMENTS PATENT DOCUMENTS

[0004] Patent Document 1 Japanese Unexamined Patent Publication No. 2020-092250 SUMMARY OF THE INVENTION PROBLEM TO BE SOLVED BY THE INVENTION

[0005] As described above, a water distribution pipe is attached to the opening hole on the back surface of the bottom plate of the cooling device. For this reason, it is required that the seal region around the opening hole has no damage. Even if the water distribution pipe is attached to a damaged seal region via the sealing member, the airtightness provided by the sealing member is lowered, and there is a risk that the coolant may leak. If the coolant leaks, the cooling performance of the cooling device is degraded, and the semiconductor module cannot be sufficiently cooled. This may lead to a decrease in the reliability of the semiconductor device.

[0006] This invention has been made in view of these points, and aims to provide a semiconductor device in which the back surface of the cooling device is less susceptible to damage. [Means for solving the problem]

[0007] According to one aspect of the present invention, the present invention comprises a semiconductor chip and a housing including an outer frame and a cooling device, wherein the cooling device comprises a top plate on which the semiconductor chip is mounted on its front surface, a bottom plate provided on the opposite side of the top plate and having an opening on its bottom surface through which a refrigerant flows in or out, and a side wall that is continuous in plan view and annular in shape, sandwiched between the top plate and the bottom plate, and defining a flow path region between the top plate and the bottom plate through which the refrigerant flows, The outer frame is made of resin, mounted on the front surface of the top plate, and in plan view, has a rectangular shape and includes four outer walls that surround the four sides of the semiconductor chip on the top plate together with the four sides of the cooling device. The housing protrudes from the bottom surface of the bottom plate on the opposite side of the semiconductor chip. and included in the lower end of the cooling device side of the four outer walls A semiconductor device is provided that further includes a spacer section. [Effects of the Invention]

[0008] According to the disclosed technology, the back surface of the cooling device is less susceptible to damage, and refrigerant can flow into and be distributed to the cooling device without leakage, thereby suppressing a decrease in cooling performance and preventing a decrease in the reliability of the semiconductor device. [Brief explanation of the drawing]

[0009] [Figure 1] This is a plan view of the semiconductor device according to the first embodiment. [Figure 2] This is a side view of the semiconductor device according to the first embodiment. [Figure 3] This is a cross-sectional view of a semiconductor device according to the first embodiment. [Figure 4] This is a rear view of the semiconductor device according to the first embodiment. [Figure 5] This is a plan view of a semiconductor unit included in the semiconductor device of the first embodiment. [Figure 6] This is a cross-sectional view of a semiconductor unit included in the semiconductor device of the first embodiment. [Figure 7]It is a perspective view (part 1) of a cooling device included in the semiconductor device according to the first embodiment. [Figure 8] It is a perspective view (part 2) of a cooling device included in the semiconductor device according to the first embodiment. [Figure 9] It is a back view of a cooling device included in the semiconductor device according to the first embodiment. [Figure 10] It is a view for explaining the flow of a refrigerant in a cooling device included in the semiconductor device according to the first embodiment. [Figure 11] It is a cross-sectional view of the semiconductor device according to the first embodiment (Modification 1-1). [Figure 12] It is a cross-sectional view of the semiconductor device according to the first embodiment (Modification 1-2). [Figure 13] It is a back view of the semiconductor device according to the first embodiment (Modification 1-3). [Figure 14] It is a side view of the semiconductor device according to the first embodiment (Modification 1-4). [Figure 15] It is a back view of the semiconductor device according to the first embodiment (Modification 1-4). [Figure 16] It is a back view (part 1) of the semiconductor device according to the first embodiment (Modification 1-5). [Figure 17] It is a back view (part 2) of the semiconductor device according to the first embodiment (Modification 1-5). [Figure 18] It is a cross-sectional view of the semiconductor device according to the second embodiment. [Figure 19] It is a back view of the semiconductor device according to the second embodiment. [Figure 20] It is a cross-sectional view of the semiconductor device according to the second embodiment (Modification 2-1). [Figure 21] It is a back view of the semiconductor device according to the second embodiment (Modification 2-1). [Figure 22] It is a cross-sectional view of the semiconductor device according to the second embodiment (Modification 2-2). [Figure 23] It is a back view of the semiconductor device according to the second embodiment (Modification 2-2). MODE FOR CARRYING OUT THE INVENTION

[0010] Hereinafter, embodiments will be described with reference to the drawings. In the following description, "front surface" and "upper surface" refer to the X-Y plane facing the upper side (+Z direction) in the semiconductor device 1 of FIG. 1. Similarly, "upper" refers to the direction toward the upper side (+Z direction) in the semiconductor device 1 of FIG. 1. "Back surface" and "lower surface" refer to the X-Y plane facing the lower side (-Z direction) in the semiconductor device 1 of FIG. 1. Similarly, "lower" refers to the direction toward the lower side (-Z direction) in the semiconductor device 1 of FIG. 1. The same directional meaning applies to other drawings as necessary. "Front surface", "upper surface", "upper", "back surface", "lower surface", "lower" and "side surface" are merely expedient expressions for specifying relative positional relationships, and do not limit the technical idea of the present invention. For example, "upper" and "lower" do not necessarily mean the vertical direction with respect to the ground. That is, the directions of "upper" and "lower" are not limited to the direction of gravity. In addition, in the following description, "main component" means that the content is 80% by volume or more.

[0011] [First Embodiment] The semiconductor device 1 according to the first embodiment will be described with reference to FIGS. 1 to 4. FIG. 1 is a plan view of the semiconductor device according to the first embodiment, and FIG. 2 is a side view of the semiconductor device according to the first embodiment. FIG. 3 is a cross-sectional view of the semiconductor device according to the first embodiment, and FIG. 4 is a back view of the semiconductor device according to the first embodiment. FIG. 2 is a side view of the Y-Z plane in FIG. 1 viewed along the X direction. FIG. 3 is a cross-sectional view taken along the dashed-dotted line Y-Y in FIG. 1. FIG. 4 is a view of the back side of the semiconductor device 1 when the semiconductor device 1 of FIG. 1 is rotated about a center line passing through the centers of outer walls 21a and 21c.

[0012] The semiconductor device 1 includes a semiconductor module 2 and a cooling device 3. The semiconductor module 2 also includes semiconductor units 10a, 10b, and 10c and a housing 20 that houses the semiconductor units 10a, 10b, and 10c. The semiconductor units 10a, 10b, and 10c housed in the housing 20 are sealed by a sealing member 26. In the first embodiment, the housing 20 also includes the cooling device 3. The semiconductor units 10a, 10b, and 10c all have the same configuration. When not distinguished, the semiconductor units 10a, 10b, and 10c will be described as semiconductor unit 10. Details of semiconductor unit 10 will be described later.

[0013] First, the enclosure 20 includes an outer frame 21, first connection terminals 22a, 22b, 22c, second connection terminals 23a, 23b, 23c, U-phase output terminal 24a, V-phase output terminal 24b, W-phase output terminal 24c, and control terminals 25a, 25b, 25c.

[0014] The outer frame 21 is roughly rectangular in plan view and is surrounded on all four sides by outer walls 21a, 21b, 21c, and 21d. The outer walls 21a and 21c are the longer sides of the outer frame 21, while the outer walls 21b and 21d are the shorter sides. The corners where the outer walls 21a, 21b, 21c, and 21d are connected do not necessarily have to be right angles and may be rounded off as shown in Figure 1. Fastening holes 21i that penetrate the outer frame 21 are formed at each corner of the front surface of the outer frame 21. The fastening holes 21i formed at the corners of the outer frame 21 are formed below the front surface of the outer frame 21. In addition, further fastening holes 21i that penetrate the outer frame 21 are formed on the outer wall 21a and 21c sides of the outer frame 21.

[0015] The outer frame 21 includes unit storage sections 21e, 21f, and 21g on its front surface, along the outer walls 21a and 21c. The unit storage sections 21e, 21f, and 21g are rectangular in shape when viewed from above. Semiconductor units 10a, 10b, and 10c are housed in the unit storage sections 21e, 21f, and 21g, respectively. The outer frame 21 further includes a cooling storage section 21h on its back surface, which is surrounded on all four sides by the outer walls 21a, 21b, 21c, and 21d. The cooling storage section 21h is located below (in the -Z direction) the unit storage sections 21e, 21f, and 21g, and is connected to them, respectively. The cooling storage section 21h houses the cooling device 3. The outer frame 21 is attached from above to the cooling device 3, on which semiconductor units 10a, 10b, and 10c are arranged in the Y direction on its front surface. When the cooling device 3 is housed in the outer frame 21 in this way, the spacer portions 21a2, 21b2, 21c2, and 21d2 at the lower ends (in the -Z direction) of the outer walls 21a, 21b, 21c, and 21d protrude in the -Z direction from the cooling device 3 (the bottom surface 33d of the cooling bottom plate 33, which will be described later). That is, the bottom surfaces of the lower ends (in the -Z direction) of the outer walls 21a1, 21b1, 21c1, and 21d, which are the bottom portions of the outer walls 21a, 21b, 21c, and 21d, are located below the cooling device 3 (the bottom surface 33d of the cooling bottom plate 33) in the -Z direction. An inlet 33a and an outlet 33b are formed on the bottom surface 33d of the cooling device 3. Details of the cooling device 3 will be described later.

[0016] In a plan view, the outer frame 21 sandwiches the unit storage sections 21e, 21f, and 21g. It is equipped with first connection terminals 22a, 22b, 22c and second connection terminals 23a, 23b, 23c, and U-phase output terminal 24a, V-phase output terminal 24b, and W-phase output terminal 24c, respectively. The outer frame 21 is First connection terminals 22a, 22b, 22c and second connection terminals 23a, 23b, 23c are located on the exterior wall 21a side. each They are equipped. Furthermore, Outer frame 21 is,The outer wall 21c side is provided with U-phase output terminal 24a, V-phase output terminal 24b, and W-phase output terminal 24c, respectively. The outer frame 21 also has nuts housed at the bottom of the openings for the first connection terminals 22a, 22b, 22c and the second connection terminals 23a, 23b, 23c, facing the openings. Similarly, the outer frame 21 has nuts housed at the bottom of the openings for the U-phase output terminal 24a, V-phase output terminal 24b, and W-phase output terminal 24c, facing the openings. Furthermore, in a plan view, the outer frame 21 is provided with control terminals 25a, 25b, and 25c along the +X-direction sides of the unit storage sections 21e, 21f, and 21g, respectively. In this case, the control terminals 25a, 25b, and 25c are each provided in two separate units.

[0017] Such an outer frame 21 includes first connection terminals 22a, 22b, 22c, second connection terminals 23a, 23b, 23c, U-phase output terminal 24a, V-phase output terminal 24b, W-phase output terminal 24c, and control terminals 25a, 25b, 25c, and is integrally molded by injection molding using a thermoplastic resin. This constitutes the housing 20. The thermoplastic resin is, for example, polyphenylene sulfide resin, polybutylene terephthalate resin, polybutylene succinate resin, polyamide resin, or acrylonitrile butadiene styrene resin.

[0018] Furthermore, the first connection terminals 22a, 22b, 22c, the second connection terminals 23a, 23b, 23c, the U-phase output terminal 24a, the V-phase output terminal 24b, the W-phase output terminal 24c, and the control terminals 25a, 25b, 25c are made of a metal with excellent conductivity. Such a metal is, for example, copper, aluminum, or an alloy mainly composed of at least one of these. Plating treatment may be applied to the surfaces of the first connection terminals 22a, 22b, 22c, the second connection terminals 23a, 23b, 23c, the U-phase output terminal 24a, the V-phase output terminal 24b, the W-phase output terminal 24c, and the control terminals 25a, 25b, 25c.

[0019] The sealing member 26 may be a thermosetting resin. Examples of thermosetting resins include epoxy resin, phenolic resin, maleimide resin, and polyester resin. Preferably, it is an epoxy resin. Furthermore, the sealing member 26 may have a filler added to it. The filler is a ceramic that is insulating and has high thermal conductivity.

[0020] Here, the outer walls 21a, 21b, 21c, and 21d include spacer portions 21a2, 21b2, 21c2, and 21d2. In particular, spacer portions 21a2 and 21c2 are included in the lower part (-Z direction) corresponding to the exposed locations of the first connection terminals 22a, 22b, and 22c, the second connection terminals 23a, 23b, and 23c, and the U-phase output terminal 24a, the V-phase output terminal 24b, and the W-phase output terminal 24c. As a result, the creepage distance from each terminal to the cooling bottom plate 33 of the cooling device 3 is extended in proportion to the height of the spacer portions 21a2 and 21c2 (see Figure 3). Therefore, the insulation properties of the semiconductor device 1 can be reliably maintained.

[0021] Next, semiconductor units 10a, 10b, and 10c will be described using Figures 5 and 6. Figure 5 is a plan view of the semiconductor unit included in the semiconductor device of the first embodiment, and Figure 6 is a cross-sectional view of the semiconductor unit included in the semiconductor device of the first embodiment. Figure 6 is a cross-sectional view along the dashed line YY in Figure 5.

[0022] The semiconductor unit 10 includes an insulating circuit board 11, semiconductor chips 12a, 12b, and lead frames 13a, 13b, 13c, 13d, 13e. The insulating circuit board 11 includes an insulating plate 11a, circuit patterns 11b1, 11b2, 11b3, and a metal plate 11c. The insulating plate 11a and the metal plate 11c are rectangular in shape when viewed from above. The corners of the insulating plate 11a and the metal plate 11c may be rounded (R-chamfered) or chamfered (C-chamfered). The size of the metal plate 11c is smaller than the size of the insulating plate 11a when viewed from above, and it is formed inside the insulating plate 11a.

[0023] The insulating plate 11a is made of a material that has insulating properties and excellent thermal conductivity. Such an insulating plate 11a is made of ceramics or insulating resin.

[0024] The circuit patterns 11b1, 11b2, and 11b3 are formed on the front surface of the insulating plate 11a. The circuit patterns 11b1, 11b2, and 11b3 are made of a metal with excellent conductivity. Such a metal is, for example, copper, aluminum, or an alloy mainly composed of at least one of these.

[0025] Circuit pattern 11b1 occupies half of the front surface of the insulating plate 11a on the side facing the +Y direction, and covers the entire area from the side facing the -X direction to the side facing the +X direction. Circuit pattern 11b2 occupies the half of the front surface of the insulating plate 11a on the side facing the -Y direction. Furthermore, circuit pattern 11b2 occupies the area from the side facing the +X direction to just before the side facing the -X direction. Circuit pattern 11b3 occupies the area on the front surface of the insulating plate 11a enclosed by circuit patterns 11b1 and 11b2.

[0026] Such circuit patterns 11b1, 11b2, and 11b3 are formed on the front surface of the insulating plate 11a as follows: A metal plate is formed on the front surface of the insulating plate 11a, and the metal plate is subjected to etching or other processing to obtain circuit patterns 11b1, 11b2, and 11b3 of a predetermined shape. Alternatively, circuit patterns 11b1, 11b2, and 11b3 cut out from a metal plate in advance may be pressed onto the front surface of the insulating plate 11a. Note that circuit patterns 11b1, 11b2, and 11b3 are just examples. The number, shape, size, and position of circuit patterns 11b1, 11b2, and 11b3 may be appropriately selected as needed.

[0027] The metal plate 11c is formed on the back surface of the insulating plate 11a. The metal plate 11c is rectangular in shape. The area of ​​the metal plate 11c in plan view is smaller than the area of ​​the insulating plate 11a, but larger than the area of ​​the region where the circuit patterns 11b1, 11b2, and 11b3 are formed. The corners of the metal plate 11c may be rounded (R-chamfered) or chamfered (C-chamfered). The metal plate 11c is smaller than the size of the insulating plate 11a and is formed over the entire surface of the insulating plate 11a, excluding the edges. The metal plate 11c is mainly composed of a metal with excellent thermal conductivity. The metal is, for example, copper, aluminum, or an alloy containing at least one of these.

[0028] As the insulating circuit board 11 having such a configuration, for example, a DCB (Direct Copper Bonding) board, an AMB (Active Metal Brazed) board, or a resin insulating board may be used. The insulating circuit board 11 may be attached to the front surface of the cooling device 3 via a bonding member (not shown). The heat generated by the semiconductor chips 12a and 12b can be conducted to the cooling device 3 via the circuit patterns 11b1 and 11b2, the insulating plate 11a, and the metal plate 11c to dissipate the heat.

[0029] The joining members 14a and 14b are solder, brazing material, or a metal sintered body. Lead-free solder is used. Lead-free solder mainly consists of an alloy containing at least two of the following: tin, silver, copper, zinc, antimony, indium, and bismuth. In addition, the solder may contain additives. Additives include, for example, nickel, germanium, cobalt, or silicon. The inclusion of additives in the solder improves wettability, gloss, and bonding strength, thereby improving reliability. The brazing material mainly consists of at least one of the following: aluminum alloy, titanium alloy, magnesium alloy, zirconium alloy, or silicon alloy. The insulating circuit board 11 can be joined to the cooling device 3 by brazing using such joining members. The metal sintered body mainly consists of, for example, silver and silver alloy. Alternatively, the joining member may be a thermal interface material. The thermal interface material is an adhesive that includes, for example, elastomer sheets, RTV (Room Temperature Vulcanization) rubber, gels, and phase change materials. By attaching the semiconductor unit 10 to the cooling device 3 via such a brazing material or thermal interface material, the heat dissipation of the semiconductor unit 10 can be improved.

[0030] The semiconductor chips 12a and 12b contain power device elements made of silicon, silicon carbide, or gallium nitride. The thickness of the semiconductor chips 12a and 12b is, for example, 40 μm or more and 250 μm or less. The power device element is an RC (Reverse-Conducting)-IGBT (Insulated Gate Bipolar Transistor). The RC-IGBT combines the functions of an IGBT, which is a switching element, and an FWD (Free Wheeling Diode), which is a diode element. The front surface of such semiconductor chips 12a and 12b is equipped with a control electrode (gate electrode) and an output electrode (source electrode). The back surface of such semiconductor chips 12a and 12b is equipped with an input electrode (collector electrode).

[0031] Furthermore, the semiconductor chips 12a and 12b may use a pair of switching elements and diode elements instead of RC-IGBTs. Examples of switching elements include IGBTs and power MOSFETs (Metal Oxide Semiconductor Field Effect Transistors). Such semiconductor chips 12a and 12b may have, for example, a drain electrode (or collector electrode) as the main electrode on the back surface, and a gate electrode and source electrode (or emitter electrode) as the control electrode and main electrode on the front surface.

[0032] The diode elements are, for example, FWDs such as SBDs (Schottky Barrier Diodes) and PiN (P-intrinsic-N) diodes. Such semiconductor chips 12a and 12b have a cathode electrode as the main electrode on the back surface and an anode electrode as the main electrode on the front surface.

[0033] The semiconductor chips 12a and 12b have their back sides connected by a bonding member 14a to predetermined circuit patterns 11b2 and 11b1. ri The joining members 14a are joined together. The joining member 14a is solder or a metal sintered body. Lead-free solder is used. Lead-free solder mainly consists of an alloy containing at least two of the following: tin, silver, copper, zinc, antimony, indium, and bismuth. In addition, the solder may contain additives. Additives include, for example, nickel, germanium, cobalt, or silicon. The inclusion of additives in the solder improves wettability, gloss, and bonding strength, thereby improving reliability. Metals used in metal sintered bodies include, for example, silver and silver alloys.

[0034] The lead frames 13a, 13b, 13c, 13d, and 13e electrically connect and wire the semiconductor chips 12a and 12b and the circuit patterns 11b1, 11b2, and 11b3. The semiconductor unit 10 may be a device that constitutes a single-phase inverter circuit. The lead frame 13a connects the output electrode of the semiconductor chip 12a and the circuit pattern 11b3. to connectIt continues. Lead frame 13c is circuit pattern 11b3 to The lead frame 13b is connected to the output electrodes of the semiconductor chip 12b and the circuit pattern 11b2. to connect It continues. Lead frame 13d is circuit pattern 11b1 to It continues. Lead frame 13e is circuit pattern 11b2 to It continues.

[0035] When such semiconductor units 10 are housed in unit housings 21e, 21f, and 21g, the other end of the lead frame 13e may be an output terminal of the semiconductor unit 10. That is, the other end of the lead frame 13e is connected to the U-phase output terminal 24a, the V-phase output terminal 24b, and the W-phase output terminal 24c, respectively.

[0036] The other end of lead frame 13d may be the positive side input terminal (P terminal). The other end of lead frame 13c may be the negative side input terminal (N terminal). That is, the other ends of lead frames 13c and 13d are connected to the first connection terminals 22a, 22b, and 22c and the second connection terminals 23a, 23b, and 23c, respectively. In addition, the control electrodes of semiconductor chips 12a and 12b are directly connected to the control terminals 25a, 25b, and 25c by wires.

[0037] Such lead frames 13a, 13b, 13c, 13d, and 13e are made of a metal with excellent conductivity. Such metals are, for example, copper, aluminum, or an alloy containing at least one of these. In addition, the surfaces of the lead frames 13a, 13b, 13c, 13d, and 13e may be plated to improve corrosion resistance.

[0038] The lead frames 13a, 13b, 13c, 13d, and 13e are joined to the circuit patterns 11b1, 11b2, and 11b3 by a joining member (not shown). The joining member may be solder or a sintered body as described above. Alternatively, the lead frames 13a, 13b, 13c, 13d, and 13e are joined to the circuit patterns 11b1, 11b2, and 11b3 by, for example, laser welding or ultrasonic welding. ri They may be joined. The lead frames 13a and 13b are joined to the output electrodes of the semiconductor chips 12a and 12b via a bonding member 14b. The bonding member 14b is made of the same material as the bonding member 14a.

[0039] Next, the cooling device 3 will be described using Figures 7 to 9. Figures 7 and 8 are perspective views of the cooling device included in the semiconductor device of the first embodiment. Figure 9 is a rear view of the cooling device included in the semiconductor device of the first embodiment. Figure 8 is a perspective view of the back side of the top plate 31 of the cooling device 3. Figure 9 is a plan view of the back side of the top plate 31 of the cooling device 3.

[0040] The cooling device 3 is equipped with an inlet 33a for refrigerant to flow into its interior and an outlet 33b for refrigerant that has circulated inside to flow out to the outside. The cooling device 3 cools the semiconductor unit 10 by releasing heat from the semiconductor unit 10 through the refrigerant. The refrigerant can be, for example, water, antifreeze (ethylene glycol aqueous solution), or long-life coolant (LLC).

[0041] Such a cooling device 3 has a rectangular shape in plan view, including long sides 30a, 30c and short sides 30b, 30d. In addition, in plan view, the cooling device 3 has fastening holes 30e formed at least at each of its four corners.

[0042] Three semiconductor units 10a, 10b, and 10c are mounted (along the -Y direction) along the long sides 30a and 30c in the center of the front surface of the cooling device 3. In Figure 9, the arrangement area of ​​the semiconductor units 10a, 10b, and 10c is shown by a dashed line. The number of semiconductor units 10 is not limited to three. Also, the arrangement position and size of the semiconductor units 10 are not limited to that of this embodiment, as long as the semiconductor units 10 are arranged in the center of the cooling device 3 (the cooling area described later). The cooling device 3 may also include a pump and a heat dissipation device (radiator). The pump introduces refrigerant into the inlet 33a of the cooling device 3 and circulates the refrigerant that has flowed out from the outlet 33b back into the inlet 33a. The heat dissipation device dissipates the heat from the refrigerant that has been conducted from the semiconductor units 10 to the outside.

[0043] Such a cooling device 3 includes a top plate 31, a side wall 32 connected annularly to the back surface of the top plate 31, and a cooling bottom plate 33 facing the top plate 31 and connected to the back surface of the side wall 32. In plan view, the top plate 31 is rectangular in shape, enclosed on all four sides by long sides 30a, 30c and short sides 30b, 30d, with fastening holes 30e formed at each of the four corners. In plan view, the corners of the top plate 31 may be rounded.

[0044] Furthermore, as shown in Figure 9, the top plate 31 is divided into a flow channel region 31a and outer edge regions 31e and 31f. As will be described later, side walls 32 are connected to the back surface of the top plate 31. The flow channel region 31a is the region enclosed by the side walls 32. The flow channel region 31a is further divided into a cooling region 31b and communication regions 31c and 31d, parallel to the long sides 30a and 30c. The cooling region 31b is a central rectangular region parallel to the long sides 30a and 30c (longitudinal direction) of the top plate 31. Multiple semiconductor units 10 are arranged in a line along the Y direction in the cooling region 31b on the front surface of the top plate 31. The front surface of the top plate 31 on which the semiconductor units 10 are mounted is formed as a flat surface without any steps in the thickness direction (Z direction), forming a single plane.

[0045] Multiple heat dissipation fins 34 are formed in the cooling region 31b on the underside of the top plate 31. The thickness (length in the Z direction) of the top plate 31 is, for example, 2.0 mm or more and 5.0 mm or less. The multiple heat dissipation fins 34 extend to connect the cooling region 31b on the underside of the top plate 31 and the cooling bottom plate 33. The height (length in the Z direction) of the multiple heat dissipation fins 34 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. Note that Figure 9 shows the plan view of the heat dissipation fins 34, and Figure 10, which will be described later, shows the side view of the heat dissipation fins 34. However, Figure 10 shows the heat dissipation fins 34 schematically and does not necessarily correspond to Figure 9. In the cooling region 31b, the number of heat dissipation fins 34 arranged in the direction of the long sides 30a and 30c is greater than the number of heat dissipation fins 34 arranged in the direction of the short sides 30b and 30d. The cooling region 31b includes the region where the heat dissipation fins 34 are provided and the flow paths between the heat dissipation fins 34. The spacing between adjacent heat dissipation fins 34 may be narrower than the width of the heat dissipation fin 34 itself. The heat dissipation fins 34 have an upper end and a lower end in the ±Z direction. The upper end of the heat dissipation fin 34 is thermally and mechanically connected to the back surface of the top plate 31. The lower end of the heat dissipation fin 34 is thermally and mechanically connected to the front surface (inside of the cooling device 3) of the cooling bottom plate 33. The upper end of the heat dissipation fin 34 may be integrally formed with the top plate 31. That is, the heat dissipation fin 34 may protrude integrally from the back surface of the top plate 31 in the -Z direction. On the other hand, the lower end of the heat dissipation fin 34 may be fixed to the front surface (inside of the cooling device 3) of the cooling bottom plate 33 by brazing or the like. Furthermore, the extension direction of the heat dissipation fins 34 with respect to the Z direction is approximately perpendicular to the main surfaces of the top plate 31 and the cooling bottom plate 33, respectively. Each of the heat dissipation fins 34 may be a pin fin. In addition, each of the multiple heat dissipation fins 34 has a rectangular cross-sectional shape parallel to the main surface of the top plate 31. In Figure 9, it forms a rhombus. This allows for a larger surface area of ​​the heat dissipation fins 34 in contact with the refrigerant compared to the case where the cross-sectional shape of the heat dissipation fins 34 is circular, thereby improving heat dissipation efficiency.

[0046] Furthermore, the multiple heat dissipation fins 34 may be arranged in the cooling region 31b of the top plate 31 such that, when refrigerant flows into the cooling region 31b, none of the sides of the rectangle are perpendicular to the main flow direction of the refrigerant in the cooling region 31b. In this embodiment, the main flow direction of the refrigerant in the cooling region 31b is the X direction (parallel to the short sides 30b, 30d). The multiple heat dissipation fins 34 are arranged in the cooling region 31b such that none of the sides of the rectangle are perpendicular to the X direction. More specifically, the multiple heat dissipation fins 34 are arranged such that none of the sides of the rectangle are perpendicular to the X direction, one diagonal is parallel to the Y direction (long sides 30a, 30c), and another diagonal is parallel to the X direction. Alternatively, the multiple heat dissipation fins 34 may be arranged such that none of the sides of the rectangle are perpendicular to the X direction, one diagonal is inclined with respect to the Y direction, and another diagonal is inclined with respect to the X direction. Compared to the case where multiple heat dissipation fins 34 are arranged in the cooling region 31b such that one of the sides of the rectangle is perpendicular to the flow direction described above, any of the above-described configurations can reduce the flow velocity loss of the refrigerant circulating in the cooling region 31b and improve heat dissipation efficiency.

[0047] Furthermore, the heat dissipation fins 34 are positioned in the direction of the shorter sides 30b and 30d rather than the direction of the longer sides 30a and 30c in the XY plane shown in Figure 9. long The shape is rhombus. Note that the cross-sectional shape of each of the multiple heat dissipation fins 34 may be polygonal, for example, a square. Alternatively, the cross-sectional shape of each of the multiple heat dissipation fins 34 may be circular, for example, a perfect circle. Furthermore, the multiple heat dissipation fins 34 may be arranged in a predetermined pattern within the cooling region 31b. The multiple heat dissipation fins 34 are arranged in a staggered pattern as shown in Figure 9. The multiple heat dissipation fins 34 may also be arranged in a square pattern within the cooling region 31b.

[0048] The communication regions 31c and 31d are adjacent to both sides of the cooling region 31b on the top plate 31 and are regions along the cooling region 31b. Therefore, the communication regions 31c and 31d are regions from the cooling region 31b to the side wall 32 (on the longer sides 30a and 30c). In the case of Figure 9, the communication regions 31c and 31d are trapezoidal in shape. Depending on the area enclosed by the side wall 32, the communication regions 31c and 31d may be rectangular, semicircular, or undulating with multiple peaks. In addition, in a plan view, the corners of the communication regions 31c and 31d may be rounded with a curved edge. This is done by rounding the edges at the joints of the side walls 32 that constitute the communication regions 31c and 31d. This allows the refrigerant flowing through the communication regions 31c and 31d to flow more easily without remaining in smooth corners. This prevents corrosion at such corners. Furthermore, the communication regions 31c and 31d do not necessarily have to be symmetrical in shape. Also, although details will be described later, the outlet 33b and inlet 33a are formed closer to the shorter sides 30b and 30d, respectively, corresponding to the communication regions 31c and 31d. In addition, the outlet 33b and inlet 33a are formed in the center of the communication regions 31c and 31d in the X direction. The communication regions 31c and 31d may have a shape that facilitates the outflow and inflow of refrigerant to and from the outlet 33b and inlet 33a. For example, the communication region 31c may have a shape that narrows as it approaches the outlet 33b, so as to force the refrigerant towards the outlet 33b.

[0049] The outer edge regions 31e and 31f are the regions outside the flow path region 31a (cooling region 31b and communication regions 31c and 31d) on the top plate 31. That is, the outer edge regions 31e and 31f are the regions from the side wall 32 of the top plate 31 to the outer edge of the top plate 31 in a plan view. The fastening holes 30e and fastening reinforcement portions 30e1 described above are formed in the outer edge regions 31e and 31f.

[0050] The side wall 32 is formed in an annular shape on the back surface of the top plate 31, surrounding the cooling region 31b and the communication regions 31c and 31d. The upper end of the side wall 32 in the +Z direction is fixed to the back surface of the top plate 31. The lower end of the side wall 32 in the -Z direction is fixed to the front surface of the cooling bottom plate 33. In the case of Figure 9, the side wall 32 has six sides, including portions parallel to the short sides 30b and 30d along the cooling region 31b, portions parallel to the long sides 30a and 30c along the communication regions 31c and 31d, and portions connecting these portions. The corners of the inner joints of the annular side wall 32 may be rounded. The side wall 32 does not have to consist of six sides, as long as it includes a rectangular cooling region 31b in plan view and includes communication regions 31c and 31d on both sides of the cooling region 31b. Furthermore, the height (length in the Z direction) of the side wall 32 corresponds to the height of the multiple heat dissipation fins 34, and is, for example, 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. Also, the thickness (length in the X direction) of the side wall 32 is such that, as described later, it is sandwiched between the top plate 31 and the cooling bottom plate 33, maintaining the strength of the cooling device 3 without reducing the cooling performance, and is, for example, 1.0 mm or more and 3.0 mm or less.

[0051] Furthermore, a fastening reinforcement portion 30e1 may be formed on the underside of the top plate 31 (the inside of the cooling device 3) around the fastening hole 30e. The fastening reinforcement portion 30e1 has a through hole corresponding to the fastening hole 30e and is a screw frame. The side wall 32 is sandwiched between the top plate 31 and the cooling bottom plate 33 to maintain the strength of the cooling device 3. Therefore, the height of the fastening reinforcement portion 30e1 is approximately the same as the height of the side wall 32. The width of the fastening reinforcement portion 30e1 (the radial length from the center of the fastening hole 30e in a plan view) is 0.7 times or more and 2.0 times or less the diameter of the fastening hole 30e.

[0052] The cooling bottom plate 33 is flat and, in plan view, has the same shape as the top plate 31. That is, in plan view, the cooling bottom plate 33 is rectangular in shape, enclosed on all four sides by its long and short sides, and fastening holes corresponding to the top plate 31 are formed at each of its four corners. The corners of the cooling bottom plate 33 may also be rounded. The cooling bottom plate 33 has a front surface and a bottom surface 33d that are parallel surfaces. The front surface and bottom surface 33d of the cooling bottom plate 33 refer to their respective main surfaces, excluding protrusions such as spacer parts, recesses, and through holes, which will be described later. Alternatively, the front surface and bottom surface 33d of the cooling bottom plate 33 may be the parts facing the placement areas on which the semiconductor units 10a, 10b, and 10c are mounted. In this embodiment, the bottom surface 33d of the cooling bottom plate 33 is formed as a flat surface without any steps and forms a single plane. Furthermore, the bottom surface 33d of the cooling bottom plate 33 and the top surface of the top plate 31 may also be parallel. The bottom surface 33d of the cooling bottom plate 33 has an inlet 33a and an outlet 33b formed therein, through which the refrigerant flows in and out. Seal regions 33a1 and 33b1 are provided around the inlet 33a and outlet 33b on the bottom surface 33d of the cooling bottom plate 33. The seal regions 33a1 and 33b1 will be described later. The inlet 33a is on the long side 30c side, corresponding to the communication region 31d, and the short side 30 b It is formed on the side. The outlet 33b is on the long side 30a side, corresponding to the communication region 31c, and the short side 30 d It is formed on the side. That is, the inlet 33a and outlet 33b are formed at positions that are point-symmetric with respect to the center point of the bottom surface 33d of the cooling bottom plate 33. When such a cooling bottom plate 33 is connected to the side wall 32, the fastening reinforcement part 30e1 is connected around the fastening hole of the cooling bottom plate 33. The cooling bottom plate 33 needs to be thick enough to maintain the overall strength of the cooling device 3 without reducing the cooling performance. In addition, the cooling bottom plate 33 needs to be strong enough for the water pipes to be attached to the inlet 33a and outlet 33b, as will be described later. For this reason, the thickness of the cooling bottom plate 33 is 1.0 times or more and 5.0 times or less the thickness of the top plate 31. More preferably, it is 2.0 times or more and 3.0 times or less. The thickness of the cooling bottom plate 33 is preferably, for example, 2.0 mm or more and 10.0 mm or less.

[0053] The interior of the cooling device 3, configured in this way, is formed by a flow path region 31a surrounded by a top plate 31, side walls 32, and a cooling bottom plate 33. The flow path region 31a is further divided into a cooling region 31b and communication regions 31c and 31d. Multiple heat dissipation fins 34 extending from the top plate 31 to the cooling bottom plate 33 are located in the cooling region 31b. The communication regions 31c and 31d are composed of the top plate 31, side walls 32, and cooling bottom plate 33. The communication region 31d is connected to the cooling region 31b. Refrigerant flowing in from the inlet 33a flows from the communication region 31d to the cooling region 31b. The communication region 31c is connected to the cooling region 31b. Refrigerant from the cooling region 31b flows into the communication region 31c and flows out from the outlet 33b. The flow of refrigerant in the cooling device 3 will be described later. In addition, the cooling device 3 is formed by the top plate 31 Outside of the flow channel region 31a and the outside of the side wall 32 and the cooling bottom plate 33 by Outer regions 31e and 31f are formed.

[0054] Cooling device 3 is ,heat The cooling device 3 is primarily composed of a metal with excellent conductivity. The metal is, for example, copper, aluminum, or an alloy containing at least one of these. Plating may be performed to improve the corrosion resistance of the cooling device 3. The plating material used in this case is, for example, nickel, nickel-phosphorus alloy, or nickel-boron alloy. The top plate 31, on which the multiple heat dissipation fins 34 are formed, can be formed by, for example, forging or casting (die casting). In the case of forging, a block-shaped member mainly composed of the above metal is pressed using a mold and plastically deformed to obtain a top plate 31 on which the multiple heat dissipation fins 34 and side walls 32 are formed. In the case of die casting, molten die-cast material is poured into a predetermined mold, cooled, and then removed from the mold to obtain a top plate 31 on which the multiple heat dissipation fins 34 and side walls 32 are formed. The die-cast material used in this case is, for example, an aluminum-based alloy. Alternatively, the top plate 31, on which multiple heat dissipation fins 34 and side walls 32 are formed, may be formed by cutting a block-shaped material mainly composed of the above-mentioned metal.

[0055] The cooling bottom plate 33 is joined to the multiple heat dissipation fins 34 and side walls 32 of the top plate 31. This joining is performed by brazing. Therefore, the back surface, which is the end of the side wall 32 extending from the main surface (back surface) of the top plate 31, and the ends of the heat dissipation fins 34 are joined to the front surface of the cooling bottom plate 33 via brazing material. If the top plate 31 is formed by casting, the brazing material used in the brazing process is a material with a lower melting point than the die-cast material. Such a brazing material is, for example, an alloy mainly composed of aluminum.

[0056] Furthermore, a fastening reinforcement portion 30e1 may be separately formed on the top plate 31 and joined to the cooling bottom plate 33 by brazing. Also, in this embodiment, a case is shown where multiple heat dissipation fins 34 are connected to the top plate 31. In addition, multiple heat dissipation fins 34 may be formed in the area of ​​the cooling bottom plate 33 corresponding to the cooling area 31b. Thus, a cooling device 3 is obtained.

[0057] Next, the flow of refrigerant in the cooling device 3 will be explained using Figure 10 (and Figure 9). Figure 10 is a diagram illustrating the flow of refrigerant in the cooling device included in the semiconductor device of the first embodiment. Note that Figure 10 is a cross-sectional view taken along the dashed line YY in Figure 9. In Figure 10, only the cooling device 3 is shown, and the housing 20 is not shown.

[0058] As previously described, the coolant is circulated inside the cooling device 3 by a pump. To circulate the coolant, a water distribution head 36a is attached to the inlet 33a via an annular rubber packing 35a in a sealing area 33a1 surrounding the inlet 33a. A water distribution pipe 37a is attached to the water distribution head 36a. Similarly, a water distribution head 36b is attached to the outlet 33b via an annular rubber packing 35b in a sealing area 33b1 surrounding the outlet 33b. A water distribution pipe 37b is attached to the water distribution head 36b. The pump is connected to the water distribution pipes 37a and 37b. The sealing areas 33a1 and 33b1 may be areas that, in a plan view, are located at a distance of 0.2 to 2.0 times the width of the inlet 33a and outlet 33b from the outer edges of the inlet 33a and outlet 33b. Here, the width of the inlet 33a and outlet 33b may be the shortest distance passing through the centroids of the inlet 33a and outlet 33b. For example, the width of the inlet 33a and outlet 33b may be the distance between the longer sides when the inlet 33a and outlet 33b are rectangular or elongated, and may be the minor axis in an ellipse or the diameter in a circle. Also, the sealing areas 33a1 and 33b1 may be the area from the outer edges of the inlet 33a and outlet 33b up to 20 mm in a plan view, and preferably the area from the outer edges of the inlet 33a and outlet 33b up to 10 mm.

[0059] As shown in Figure 9, the refrigerant flowing in from the inlet 33a flows into the communication region 31d and spreads within the communication region 31d. The refrigerant flowing in from the communication region 31d spreads out towards the short side 30b (Y direction) and also towards the long side 30a (X direction). In addition, when the refrigerant flows in from the inlet 33a, it spreads directly towards the long side 30a (X direction). In this way, the refrigerant flows into the entire side of the cooling region 31b facing the long side 30c.

[0060] As shown in Figure 10, the refrigerant that flows into the side of the cooling region 31b (on the long side 30c) circulates between the multiple heat dissipation fins 34 towards the long side 30a (X direction). Heat from the heated semiconductor unit 10 is conducted to the multiple heat dissipation fins 34 via the top plate 31. The refrigerant absorbs heat from the multiple heat dissipation fins 34 as it circulates between them. As a result, heat from the semiconductor unit 10 is more easily conducted to the multiple heat dissipation fins 34. This allows more heat to be conducted to the refrigerant circulating in the gaps between the heat dissipation fins 34, improving cooling performance.

[0061] As shown in Figure 9 (and Figure 10), the refrigerant that has absorbed heat flows into the communication region 31c from the side opposite the long side 30a of the cooling region 31b, and flows out to the outside from the outlet 33b. At this time, the refrigerant flows out containing the heat conducted from the multiple heat dissipation fins 34. The flowed-out refrigerant is cooled by the heat dissipation device and then pumped back into the cooling device 3 from the inlet 33a. The semiconductor unit 10 is cooled by the circulation of the refrigerant to the cooling device 3, which causes the heat from the semiconductor unit 10 to flow out to the outside.

[0062] Thus, the bottom surface 33d of the cooling bottom plate 33 of the cooling device 3 needs to be sealed and fitted with drainage pipes 37a and 37b to properly supply and discharge refrigerant to the inlet 33a and outlet 33b. If the bottom surface 33d of the cooling bottom plate 33 is damaged, particularly in the sealing area around the inlet 33a and outlet 33b where the drainage pipes 37a and 37b are attached, the airtightness will not be maintained. As a result, there is a risk that refrigerant may leak out from the inlet 33a and outlet 33b.

[0063] Therefore, the outer frame 21 (outer walls 21a, 21b, 21c, 21d) of the housing 20 of the semiconductor device 1 is provided with spacer portions 21a2, 21b2, 21c2, 21d2 that protrude from the bottom surface 33d of the cooling bottom plate 33 on the opposite side of the semiconductor chips 12a, 12b. When the semiconductor device 1 is placed on any mounting surface, for example, the back surface of the cooling device 3 (the bottom surface 33d of the cooling bottom plate 33) is left gap from the mounting surface due to the spacer portions 21a2, 21b2, 21c2, 21d2. As a result, the bottom surface 33d of the cooling bottom plate 33 does not directly touch the mounting surface and is less susceptible to damage. For example, when such a semiconductor device 1 is mounted on a predetermined tray and packed in a box for shipment, damage to the back surface of the cooling device 3 (the bottom surface 33d of the cooling bottom plate 33) is prevented. At the destination, the airtight seal between the water pipes 37a and 37b attached to the cooling device 3 of the semiconductor device 1 and the inlet 33a and outlet 33b of the cooling bottom plate 33 is maintained. As a result, leakage of refrigerant from the cooling device 3 is prevented, a decrease in the cooling capacity of the cooling device 3 is suppressed, and the semiconductor unit 10 can be properly cooled. As a result, a decrease in the reliability of the semiconductor device 1 can be suppressed. In particular, it is necessary to prevent damage to the sealing areas 33a1 and 33b1 around the inlet 33a and outlet 33b of the semiconductor device 1. On the other hand, depending on the shape and type of water pipe, the sealing areas 33a1 and 33b1 may extend over a wide area around the inlet 33a and outlet 33b. Therefore, by preventing damage to the entire back surface of the cooling device 3, it is possible to accommodate all types of water pipes.

[0064] Furthermore, the bottom portions 21a1, 21b1, 21c1, and 21d1 of the outer walls 21a, 21b, 21c, and 21d of the outer frame 21 may be parallel to the mounting surface, or their cross-section may be semicircular. In addition, the corners of the spacer portions 21a2, 21b2, 21c2, and 21d2 of the outer walls 21a, 21b, 21c, and 21d may be rounded (R-chamfered) or rounded (C-chamfered).

[0065] Next, various configurations of the spacer portions of the outer walls 21a, 21b, 21c, and 21d of the outer frame 21 of the semiconductor device 1 will be described. In the following modifications, unless otherwise specified, only the spacer portions of the outer walls 21a, 21b, 21c, and 21d differ from the semiconductor device 1 of the first embodiment. Other than these, the components are the same as those of the semiconductor device 1.

[0066] [Variation 1-1] A semiconductor device of Modification 1-1 of the first embodiment will be described with reference to Figure 11. Figure 11 is a cross-sectional view of the semiconductor device of the first embodiment (Modification 1-1). The cooling device 3a included in the semiconductor device 1a has water distribution heads 36a and 36b connected to the inlet 33a and outlet 33b of the cooling bottom plate 33, respectively. The water distribution heads 36a and 36b are formed on the bottom surface 33d of the cooling bottom plate 33 such that one end is connected to the inlet 33a and outlet 33b, respectively, and the other end (head bottom surface 36a1, 36b1) extends to the opposite side of the semiconductor chips 12a and 12b. The water distribution heads 36a and 36b may each be integrally formed with the cooling device 3a (cooling bottom plate 33). In this case, the outer walls 21a, 21b, 21c, and 21d of the outer frame 21 surround the side wall 32 of the cooling device 3a on all four sides, including the water distribution heads 36a and 36b. Furthermore, the outer walls 21a, 21b, 21c, and 21d are provided with spacer portions 21a2, 21b2, 21c2, and 21d2 that protrude downward (in the -Z direction) from the bottom surfaces 36a1 and 36b1 of the water distribution heads 36a and 36b.

[0067] Even with such a semiconductor device 1a, when placed on any mounting surface, the bottom surfaces 36a1 and 36b1 of the water distribution heads 36a and 36b are separated from the mounting surface by the spacer portions 21a2, 21b2, 21c2, and 21d2. As a result, the bottom surfaces 36a1 and 36b1 of the water distribution heads 36a and 36b do not directly touch the mounting surface and are less susceptible to damage. Water distribution fittings connected to the pump are connected to the water distribution heads 36a and 36b via rubber gaskets. In this case, if the bottom surfaces 36a1 and 36b1 of the water distribution heads 36a and 36b are damaged, the airtight seal between the water distribution heads 36a and 36b and the water distribution fittings cannot be maintained. In the semiconductor device 1a, damage to the bottom surfaces 36a1 and 36b1 of the water distribution heads 36a and 36b attached to the cooling device 3a is prevented. The airtight seal between the water distribution heads 36a and 36b and the water distribution joint is maintained. As a result, leakage of refrigerant to the water distribution heads 36a and 36b is prevented, the decrease in the cooling capacity of the cooling device 3a is suppressed, and the semiconductor unit 10 (semiconductor unit 10b in Figure 11) can be properly cooled. As a result, the decrease in the reliability of the semiconductor device 1a can be suppressed.

[0068] Furthermore, semiconductor device 1a also includes spacer portions 21a2 and 21c2 in the lower part (-Z direction) corresponding to the exposed locations of the first connection terminals 22a, 22b, 22c, the second connection terminals 23a, 23b, 23c, the U-phase output terminal 24a, the V-phase output terminal 24b, and the W-phase output terminal 24c. In addition, compared to semiconductor device 1 of the first embodiment, the creepage distance from each terminal to the cooling bottom plate 33 of the cooling device 3a is extended by the height of the water distribution heads 36a and 36b (see Figure 11). As a result, the insulation properties of semiconductor device 1a can be maintained more reliably.

[0069] [Variation 1-2] A semiconductor device of Modification 1-2 of the first embodiment will be described with reference to Figure 12. Figure 12 is a cross-sectional view of the semiconductor device of the first embodiment (Modification 1-2). Note that Figure 12 is a cross-sectional view at the location corresponding to Figure 3. The outer walls 21a, 21b, 21c, and 21d of the outer frame 21 included in the semiconductor device 1b include a return fold inward from the position of the bottom surface 33d of the cooling bottom plate 33. This return fold supports the cooling bottom plate 33. Note that Figure 12 shows the returns 21a3 and 21c3 folded in by the outer walls 21a and 21c. The width of this return (the length of the returns 21a3 and 21c3 in the ±X direction in Figure 12) should be such that it does not block the fastening holes 21i of the cooling bottom plate 33.

[0070] In this case, the thickness (height) of the flaps of the outer walls 21a, 21b, 21c, and 21d functions as a spacer. In Figure 12, the spacer parts 21a2 and 21c2 are shown. When the semiconductor device 1b is placed on the mounting surface, the semiconductor device 1b has a gap between it and the mounting surface due to these spacer parts (spacer parts 21a2 and 21c2 in Figure 12). As a result, the bottom surface 33d of the cooling bottom plate 33 does not directly touch the mounting surface and is less susceptible to damage. In addition, the cooling device 3 is supported by the flaps of the outer walls 21a, 21b, 21c, and 21d. Therefore, even if it is subjected to an external impact, the cooling device 3 is protected and its detachment is prevented.

[0071] In such a semiconductor device 1b, the overall thickness of the outer walls 21a, 21b, 21c, and 21d of the outer frame 21 may be uniform. That is, the thickness of the outer walls 21a, 21b, 21c, and 21d of the outer frame 21 up to the cooling device 3 and the thickness of the return are approximately the same. Alternatively, the thickness of the return of the outer walls 21a, 21b, 21c, and 21d of the outer frame 21 may be made thicker than other areas to raise the spacer portion.

[0072] Furthermore, semiconductor device 1b also includes spacer portions 21a2 and 21c2 in the lower part (-Z direction) corresponding to the exposed locations of the first connection terminals 22a, 22b, 22c, the second connection terminals 23a, 23b, 23c, the U-phase output terminal 24a, the V-phase output terminal 24b, and the W-phase output terminal 24c. In addition, compared to semiconductor device 1 of the first embodiment, the creepage distance from each terminal to the cooling bottom plate 33 of the cooling device 3 is further extended by the length of the returns 21a3 and 21c3 (see Figure 12). As a result, the insulating properties of semiconductor device 1b can be maintained more reliably.

[0073] [Modification 1-3] A semiconductor device of modification 1-3 of the first embodiment will be described with reference to Figure 13. Figure 13 is a rear view of the semiconductor device of the first embodiment (modification 1-3). Spacer portions 21j2 are included at the corners of the outer walls 21a, 21b, 21c, and 21d of the outer frame 21 of the semiconductor device 1c in a plan view, so as to cover the portion of the fastening hole 21i that faces the outer walls 21a, 21b, 21c, and 21d. That is, the bottom portion 21j1 of the outer wall of the spacer portion 21j2 protrudes below the bottom surface 33d of the cooling bottom plate 33 (in the -Z direction).

[0074] When such a semiconductor device 1c is placed on a mounting surface, the semiconductor device 1c is stably mounted on the mounting surface by the spacer portions 21j2 at its four corners, while also having gaps. As a result, the bottom surface 33d of the cooling bottom plate 33 does not directly touch the mounting surface and is less susceptible to damage. In addition, since the spacer portions 21j2 are provided so as to surround the fastening holes 21i, the fastening holes 21i are protected.

[0075] In semiconductor device 1c, if only a gap is left between the back surface of the cooling device 3 (the bottom surface 33d of the cooling bottom plate 33) and the mounting surface, spacer portions may be provided at least one pair of diagonal corners of the outer walls 21a, 21b, 21c, and 21d of the outer frame 21 in a rectangular shape when viewed from above. Also, semiconductor device 1c may include a return finial as in Modification 1-3.

[0076] [Modifications 1-4] The semiconductor device of Modification 1-4 of the first embodiment will be described with reference to Figures 14 and 15. Figure 14 is a side view of the semiconductor device of the first embodiment (Modification 1-4), and Figure 15 is a rear view of the semiconductor device of the first embodiment (Modification 1-4). Note that Figure 14 corresponds to the side view of Figure 2 in semiconductor device 1d.

[0077] Spacer portions 21k2 are located on the outer walls 21a, 21b, 21c, and 21d of the outer frame 21 of the semiconductor device 1d, and on the inlet 33a and outlet 33b outer circumference The spacer portion 21k2 is included so as to cover the portion facing the outer walls 21a, 21b, 21c, and 21d. In a plan view, each spacer portion 21k2 is L-shaped with the vicinity of the fastening hole 21i as its apex angle. That is, the outer wall bottom portion 21k1 of the spacer portion 21k2 protrudes below (in the -Z direction) the bottom surface 33d of the cooling bottom plate 33.

[0078] The inlet 33a and outlet 33b are formed on the diagonal corners of the cooling bottom plate 33, respectively. The inlet 33a is provided near the corner formed by the outer walls 21b and 21c of the cooling bottom plate 33, and the outlet 33b is provided near the corner formed by the outer walls 21a and 21d. The spacer portion 21k2 is provided at least on the inlet 33a outer circumference It is sufficient that the portion facing the outer walls 21c and 21b is included. In Figure 15, the spacer portion 21k2 is longer than the portion where the inlet 33a faces the outer walls 21c and 21b, and forms an L shape. Similarly, the spacer portion 21k2 is included in the portion facing the outlet 33b outer circumference It is longer than the portion facing the exterior walls 21a and 21d, forming an L-shape.

[0079] When the semiconductor device 1d is placed on the mounting surface, the semiconductor device 1d is stably mounted on the mounting surface by the L-shaped spacer portion 21k2 at the corner in a plan view, while also having a gap. As a result, the bottom surface 33d of the cooling bottom plate 33 does not directly touch the mounting surface and is less susceptible to damage. In addition, since the spacer portion 21k2 is provided so as to surround the inlet 33a and outlet 33b, the inlet 33a and outlet 33b are protected.

[0080] In semiconductor device 1d, the spacer portion may be included to cover the portion facing the outer walls 21a, 21b, 21c, and 21d of the fastening holes 21i at diagonal corners (upper left and lower right in Figure 15) other than the inlet 33a and outlet 33b. This protects not only the inlet 33a and outlet 33b but also the fastening holes 21i at all four corners. Furthermore, semiconductor device 1d may also include a return rib as shown in Modification 1-3.

[0081] [Variations 1-5] A semiconductor device of Modification 1-5 of the first embodiment will be described with reference to Figures 16 and 17. Figures 16 and 17 are rear views of the semiconductor device of the first embodiment (Modification 1-5). In Figures 16 and 17, the exposed positions of the first connection terminals 22a, 22b, 22c, the second connection terminals 23a, 23b, 23c, the U-phase output terminal 24a, the V-phase output terminal 24b, and the W-phase output terminal 24c on the front side when the semiconductor device 1e is viewed from the back side are indicated by dashed lines.

[0082] In the semiconductor device 1e shown in Figure 16, spacer portions are included in the outer walls 21a, 21b, 21c, and 21d of the outer frame 21 in the portions corresponding to the exposed locations of the first connection terminals 22a, 22b, and 22c, the second connection terminals 23a, 23b, and 23c, the U-phase output terminal 24a, the V-phase output terminal 24b, and the W-phase output terminal 24c.

[0083] In other words, the outer wall 21c includes spacer portions 21n2, 21o2, and 21p2 in the portions corresponding to the exposed locations of the U-phase output terminal 24a, V-phase output terminal 24b, and W-phase output terminal 24c. The bottom portions 21n1, 21o1, and 21p1 of the outer wall of the spacer portions 21n2, 21o2, and 21p2 protrude below (in the -Z direction) the bottom surface 33d of the cooling bottom plate 33.

[0084] The outer wall 21a includes a spacer portion 21q2 connected to it, which includes portions corresponding to the exposed locations of the first connection terminals 22b, 22c and the second connection terminals 23b, 23c. The bottom portion 21q1 of the outer wall of the spacer portion 21q2 protrudes below (in the -Z direction) the bottom surface 33d of the cooling bottom plate 33.

[0085] The outer wall 21a includes a spacer portion 21r2 connected to it, which includes portions corresponding to the exposed locations of the first connection terminal 22a and the second connection terminal 23a. The bottom portion 21r1 of the outer wall of the spacer portion 21r2 protrudes below (in the -Z direction) the bottom surface 33d of the cooling bottom plate 33. In the semiconductor device 1e shown in Figure 16, the spacer portion may be included in the outer wall 21a without being connected, in portions corresponding to the exposed locations of the first connection terminals 22a, 22b, 22c and the second connection terminals 23a, 23b, 23c.

[0086] Furthermore, the semiconductor device 1e does not necessarily have to include a spacer portion for each terminal. For example, as shown in Figure 17, the outer wall 21a of the semiconductor device 1e includes a spacer portion 21m2 connected to it, which includes portions corresponding to the exposed locations of the first connection terminals 22a, 22b, 22c and the second connection terminals 23a, 23b, 23c. The bottom of the outer wall 21m1 of the spacer portion 21m2 protrudes below the bottom surface 33d of the cooling bottom plate 33 (in the -Z direction). As shown in Figure 17, the outer wall 21c of the semiconductor device 1e includes a spacer portion 21l2 connected to it, which includes portions corresponding to the exposed locations of the U-phase output terminal 24a, the V-phase output terminal 24b, and the W-phase output terminal 24c. The bottom of the outer wall 21l1 of the spacer portion 21l2 protrudes below the bottom surface 33d of the cooling bottom plate 33 (in the -Z direction).

[0087] When the semiconductor device 1e is placed on the mounting surface, the spacer portions 21n2, 21o2, 21p2, 21q2, 21r2 and 21l2, 21m2 ensure that it is stably mounted on the mounting surface while leaving a gap. As a result, the bottom surface 33d of the cooling bottom plate 33 does not directly touch the mounting surface and is less susceptible to damage. The semiconductor device 1e may also include a finial, as shown in Modification 1-3.

[0088] Furthermore, the outer walls 21a, 21b, 21c, and 21d include the spacer portions 21n2, 21o2, 21p2, 21q2, 21r2 and 21l2, 21m2 in the portions corresponding to the exposed locations of the first connection terminals 22a, 22b, 22c, the second connection terminals 23a, 23b, 23c, the U-phase output terminal 24a, the V-phase output terminal 24b, and the W-phase output terminal 24c. As a result, the creepage distance from each terminal to the cooling bottom plate 33 of the cooling device 3 extends in accordance with the height of the spacer portions 21n2, 21o2, 21p2, 21q2, 21r2 and 21l2, 21m2. This ensures that the insulation properties of the semiconductor device 1e are reliably maintained.

[0089] Furthermore, by including spacer portions (not indicated by reference numerals) in the lower part (-Z direction) corresponding to each terminal, as in the first embodiment and modified examples 1-1, 1-2, and 1-5, the creepage distance between each terminal and the cooling device 3 can be increased. As a result, the height (length in the Z direction) of the outer frame 21 can be made thinner while ensuring an appropriate creepage distance. Alternatively, while ensuring an appropriate creepage distance, each terminal can be extended not only from the top surface of the outer frame 21, but also from the middle of the outer walls 21a, 21b, 21c, and 21d of the outer frame 21. In this way, it becomes easy to change the height of the outer frame 21 and the arrangement of each terminal in the height direction (Z direction) while ensuring an appropriate creepage distance.

[0090] [Second Embodiment] The semiconductor device of the second embodiment will be described with reference to Figures 18 and 19. Figure 18 is a cross-sectional view of the semiconductor device of the second embodiment, and Figure 19 is a rear view of the semiconductor device of the second embodiment. Note that Figure 18 is a cross-sectional view taken along the dashed line YY in Figure 19.

[0091] The semiconductor device 1f also includes a semiconductor module 2 and a cooling device 3. The housing 20 included in the semiconductor module 2 comprises an outer frame 21 that includes semiconductor units 10a, 10b, and 10c. In the second embodiment, the outer frame 21 is joined to the cooling device 3. Therefore, the housing 20 can be considered to include the outer frame 21 and the cooling device 3.

[0092] The cooling device 3 has the same configuration as in the first embodiment. In this second embodiment, a spacer portion 33c is provided in the center of the bottom surface 33d of the cooling bottom plate 33 of the cooling device 3. . The corners of the spacer portion 33c may be rounded (R-chamfered) or rounded (C-chamfered). The spacer portion 33c may be integrally formed with the bottom surface 33d of the cooling bottom plate 33.

[0093] When such a semiconductor device 1f is placed on any mounting surface, similar to the first embodiment, a gap is created between the back surface of the cooling device 3 (the bottom surface 33d of the cooling bottom plate 33) and the mounting surface due to the spacer portion 33c. As a result, the bottom surface 33d of the cooling bottom plate 33 does not directly touch the mounting surface and is less susceptible to damage. The airtight seal between the water pipes 37a and 37b attached to the cooling device 3 of the semiconductor device 1f and the inlet 33a and outlet 33b of the cooling bottom plate 33 is maintained. Therefore, leakage of refrigerant from the cooling device 3 is prevented, a decrease in the cooling capacity of the cooling device 3 is suppressed, and the semiconductor unit 10 can be properly cooled. As a result, a decrease in the reliability of the semiconductor device 1f can be suppressed.

[0094] The spacer portion 33c must be positioned in the center of the bottom surface 33d of the cooling bottom plate 33 so as to be stably positioned on the mounting surface. In this case, the spacer portion 33c is positioned excluding the seal areas 33a1 and 33b1. The spacer portion 33c must also have an area that allows it to be stably positioned on the mounting surface. The lengths of the long side and short side of the spacer portion 33c may be, for example, one-third or more of the long side and short side of the cooling bottom plate 33. Furthermore, the spacer portion 33c is not limited to being rectangular in plan view as long as it is stably positioned. The spacer portion 33c may be, for example, triangular, star-shaped, circular, or elliptical in shape. Alternatively, it may form a frame shape.

[0095] In this way, a spacer portion is provided on the bottom surface 33d of the cooling bottom plate 33 of the cooling device 3 so that the cooling device 3 does not come into direct contact with the mounting surface. Various forms of such a spacer portion will be described below as modifications. In the following modifications, the semiconductor device 1f includes the same components as the semiconductor device 1f, except for the cooling bottom plate 33 of the semiconductor device 1f.

[0096] [Variation 2-1] A semiconductor device 1g of the second embodiment, modified example 2-1, will be described with reference to Figures 20 and 21. Figure 20 is a cross-sectional view of the semiconductor device of the second embodiment (modified example 2-1), and Figure 21 is a rear view of the semiconductor device of the second embodiment (modified example 2-1). Note that Figure 20 is a cross-sectional view taken along the dashed line YY in Figure 21.

[0097] As previously described, the bottom surface 33d of the cooling bottom plate 33 of the cooling device 3 included in the semiconductor device 1g has an inlet 33a and an outlet 33b formed diagonally on one diagonal. Multiple spacer portions 33c1, 33c2, 33c3, and 33c4 are provided on the other diagonal relative to the bottom surface 33d of the cooling bottom plate 33 of the cooling device 3. Note that the number of spacer portions 33c1, 33c2, 33c3, and 33c4 is not limited to four, but may be three, five or more. Alternatively, rod-shaped spacer portions may be arranged on the other diagonal. Furthermore, spacer portions 33c5 and 33c6 are positioned perpendicular to the other diagonal relative to the bottom surface 33d of the cooling bottom plate 33 of the cooling device 3, avoiding the inlet 33a and outlet 33b (and the sealing area). (Intersection) They are formed in the direction of. The spacer portions 33c5 and 33c6 are also not limited to one each, but may be formed in two or more places, excluding the seal regions 33a1 and 33b1.

[0098] When such a semiconductor device 1g is placed on any mounting surface, similar to the first embodiment, the back surface of the cooling device 3 (the bottom surface 33d of the cooling bottom plate 33) is left gap from the mounting surface by the spacer portions 33c1, 33c2, 33c3, 33c4 and 33c5, 33c6. As a result, the bottom surface 33d of the cooling bottom plate 33 does not directly touch the mounting surface and is less susceptible to damage. Therefore, the water pipes 37a, 37b and the inlet 33a and outlet 33b of the cooling bottom plate 33 can be connected to the cooling device 3 of the semiconductor device 1g while maintaining airtightness. As a result, leakage of refrigerant from the cooling device 3 is prevented, a decrease in the cooling capacity of the cooling device 3 is suppressed, and the semiconductor unit 10 can be properly cooled. As a result, a decrease in the reliability of the semiconductor device 1g can be suppressed.

[0099] Furthermore, the spacer portions 33c1, 33c2, 33c3, 33c4, 33c5, and 33c6, similar to the spacer portion 33c in the second embodiment, may not be limited to a rectangular shape in plan view, but may be triangular, star-shaped, circular, or elliptical in shape, for example, so that the semiconductor device 1g is stably positioned on the mounting surface. Alternatively, they may be hemispherical.

[0100] [Modification 2-2] A semiconductor device of modification 2-2 of the second embodiment will be described with reference to Figures 22 and 23. Figure 22 is a cross-sectional view of the semiconductor device of the second embodiment (modification 2-2). Figure 23 is a rear view of the semiconductor device of the second embodiment (modification 2-2). Note that Figure 22 is a cross-sectional view along the dashed line YY in Figure 23.

[0101] A convex, annular spacer portion 33c7 is formed continuously along the entire outer edge of the bottom surface 33d of the cooling bottom plate 33 of the cooling device 3 included in the semiconductor device 1h. Such a spacer portion 33c7 is obtained by performing metalworking such as cutting, pressing, or rolling so that its entire outer edge protrudes from the bottom surface 33d of the cooling bottom plate 33.

[0102] When such a semiconductor device 1h is placed on any mounting surface, similar to the first embodiment, a gap is created between the back surface of the cooling device 3 (the bottom surface 33d of the cooling bottom plate 33) and the mounting surface due to the spacer portion 33c7. As a result, the bottom surface 33d of the cooling bottom plate 33 does not directly touch the mounting surface and is less susceptible to damage. Therefore, the water pipes 37a and 37b and the inlet 33a and outlet 33b of the cooling bottom plate 33 can be connected to the cooling device 3 of the semiconductor device 1h while maintaining airtightness. This prevents refrigerant leakage from the cooling device 3, suppresses a decrease in the cooling capacity of the cooling device 3, and allows the semiconductor unit 10 to be properly cooled. As a result, a decrease in the reliability of the semiconductor device 1h can be suppressed.

[0103] The spacer portion 33c7 does not necessarily have to be formed around the entire outer edge of the cooling bottom plate 33, as long as there is a gap between the back surface of the cooling device 3 and the mounting surface. For example, similar to the spacer portion 21j2 in Modification 1-3 (Figure 13), it may be formed at at least one pair of diagonal corners in a plan view of the cooling bottom plate 33. In this case, the spacer portion 33c7 is formed to surround the fastening hole 21i. Also, similar to the spacer portion 21k2 in Modification 1-4 (Figure 15), the spacer portion 33c7 is formed at least around the inlet 33a and the outer circumference of inlet 33b It may be formed to include a portion that faces the surface. [Explanation of Symbols]

[0104] 1,1a,1b,1c,1d,1e,1f,1g,1h Semiconductor device 2 Semiconductor Modules 3,3a Cooling device 10, 10a, 10b, 10c Semiconductor Unit 11 Insulated circuit board 11a Insulating board 11b1, 11b2, 11b3 circuit patterns 11c metal plate 12a, 12b semiconductor chips 13a, 13b, 13c, 13d, 13e Lead Frames 14a, 14b Joining members 20 cabinets 21 Outer frame 21a, 21b, 21c, 21d Exterior walls 21a1,21b1,21c1,21d1,21j1,21k1,21l1,21m1,21n1,21o1,21p1,21q1,21r1 Bottom of outer wall 21a2,21b2,21c2,21d2,21j2,21k2,21l2,21m2,21n2,21o2,21p2,21q2,21r2 Spacer section 21a3,21c3 return 21e, 21f, 21g Unit storage compartment 21h Cooling storage compartment 21i fastening hole 22a, 22b, 22c First connection terminal 23a, 23b, 23c Second connection terminal 24a U phase output terminal 24b V phase output terminal 24c W phase output terminal 25a, 25b, 25c control terminals 26 Sealing member 30a, 30c Long side 30b, 30d Short side 30e fastening hole 30e1 Fastening reinforcement section 31 Top plate 31a Flow channel region 31b Cooling area 31c,31d Communication area 31e, 31f outer region 32 Side wall 33 Cooling bottom plate 33a Inlet 33a1, 33b1 sealing area 33b Outlet 33c, 33c1, 33c2, 33c3, 33c4, 33c5, 33c6, 33c7 Spacer section 33d bottom 34 heat dissipation fins 35a, 35b Rubber gasket 36a, 36b Water distribution head 36a1, 36b1 Head bottom 37a,37b Water pipe

Claims

1. Semiconductor chips and A housing including an outer frame and a cooling device, Equipped with, The cooling device comprises a top plate on which the semiconductor chip is mounted on its front surface, a bottom plate provided on the opposite side of the top plate and having an opening on its bottom surface through which the refrigerant flows in or out, and a side wall that forms a continuous annular shape in plan view, is sandwiched between the top plate and the bottom plate, and defines a flow path region between the top plate and the bottom plate through which the refrigerant flows. The outer frame is made of resin, mounted on the front surface of the top plate, and in plan view, has a rectangular shape and includes four outer walls that surround the four sides of the semiconductor chip on the top plate together with the four sides of the cooling device. The housing further comprises spacer portions that protrude beyond the bottom surface of the bottom plate toward the semiconductor chip and are included in the lower ends of the four outer walls toward the cooling device. Semiconductor equipment.

2. The inner surfaces of the four outer walls are adjacent to the bottom plate of the cooling device and surround the bottom plate. The semiconductor device according to claim 1.

3. Fastening holes are formed at the corners of the bottom surface of the bottom plate, The spacer portion is included at least at the diagonal corners of the rectangular outer frame in plan view, so as to cover the portion of the outer circumference of the fastening hole that faces the outer wall. The semiconductor device according to claim 1 or 2.

4. The spacer portion is included at all corners of the outer frame, such as to cover the portion of the outer circumference of the fastening hole that faces the outer wall. The semiconductor device according to claim 3.

5. The spacer portion is included in the outer wall in an annular manner, continuous with the outer wall along the lower end of the outer wall. A semiconductor device according to any one of claims 1 to 4.

6. The aforementioned opening includes an inlet for inflow and an outlet for outflow, The inlet and outlet are formed on opposite corners of one diagonal of the bottom surface of the bottom plate, The spacer portion is included in the outer frame corners adjacent to the opposing corners of the lower end of the outer wall, respectively, so as to cover the portion where the inlet and outlet face the outer wall. The semiconductor device according to claim 3.

7. The outer frame is equipped with an external terminal, one end of which is electrically connected to the semiconductor chip and the other end of which is exposed. The spacer portion is included in the lower end portion of the outer wall corresponding to the location where the other end of the external terminal is exposed. The semiconductor device according to claim 1 or 2.

8. The outer frame is provided with a plurality of external terminals whose other ends are exposed from the outer frame, The spacer portion is included in a plurality of parts of the lower end of the outer wall that correspond to the other ends of the plurality of external terminals, The semiconductor device according to claim 7.

9. The lower end of the side wall, which includes the spacer portion, has a return portion that extends parallel to the bottom plate. A semiconductor device according to any one of claims 1 to 8.

10. A water distribution head is formed on the bottom surface of the bottom plate of the cooling device, with one end connecting to the opening and the other end extending to the opposite side of the semiconductor chip. The spacer portion protrudes from the other end of the water distribution head on the opposite side of the semiconductor chip. The semiconductor device according to claim 1 or 2.

11. Semiconductor chips and A housing including an outer frame and a cooling device, Equipped with, The cooling device comprises a top plate on which the semiconductor chip is mounted on its front surface, a bottom plate provided on the opposite side of the top plate and having an opening on its bottom surface through which the refrigerant flows in or out, and a side wall that forms a continuous annular shape in plan view, is sandwiched between the top plate and the bottom plate, and defines a flow path region between the top plate and the bottom plate through which the refrigerant flows. The housing further includes a spacer portion that protrudes from the bottom surface of the bottom plate on the opposite side of the semiconductor chip, The bottom surface of the bottom plate of the cooling device includes a sealing area provided around the opening, surrounding the opening. The spacer portion is formed on the bottom surface of the bottom plate of the cooling device, excluding the sealing area. Semiconductor equipment.

12. The aforementioned spacer portion is columnar in shape. The semiconductor device according to claim 11.

13. The spacer portion is formed in a region including the center of the bottom surface of the bottom plate. The semiconductor device according to claim 12.

14. The aforementioned opening includes an inlet for inflow and an outlet for outflow, The inlet and outlet are formed on opposite corners of one diagonal of the bottom surface of the bottom plate, The spacer portion is formed in multiple locations along the other diagonal of the bottom surface of the bottom plate. The semiconductor device according to claim 12.

15. The spacer portion is further formed in multiple directions perpendicular to the other diagonal of the bottom surface of the bottom plate, avoiding the opening hole. The semiconductor device according to claim 14.

16. The spacer portion is formed on the outer edge of the bottom surface of the bottom plate. The semiconductor device according to claim 11.

17. The spacer portion is formed in an annular shape, continuous with the outer edge of the bottom surface of the bottom plate. The semiconductor device according to claim 16.

18. Fastening holes are formed at the corners of the bottom surface of the bottom plate, The spacer portion is formed at least at the diagonal corners of the bottom surface of the rectangular bottom plate in a plan view, so as to cover the outer circumference of the fastening hole. The semiconductor device according to claim 16.

19. The aforementioned opening includes an inlet for inflow and an outlet for outflow, The inlet and outlet are formed on opposite corners of one diagonal of the bottom surface of the bottom plate, The spacer portion is formed on the corners facing the outer edge of the bottom surface of the bottom plate, so as to cover the portion facing the outer circumference of the inlet and outlet. The semiconductor device according to claim 16.

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