Semiconductor device

Abstract

To provide a semiconductor device that suppresses an increase in pressure loss of a refrigerant, improves cooling performance, and suppresses a decrease in reliability.SOLUTION: In a semiconductor device that includes a semiconductor unit, a heat sink and a cooling device, the cooling device is provided on the rear surface of the heat sink, and comprises a housing 30, a reservoir part 31 and a guide part 32. The guide part 32 is formed on a bottom surface while having one end connected inside a short side wall 31b and the other end connected to the one end of the short side wall 31b across an inflow port 31g to partition off a guide region 32i communicating with the inflow port 31g and a reservoir region 31i outside the guide region 32i. The guide part 32 is further so constituted that the guide region 32i of the guide part 32 becomes smaller with the distance from the inflow port 31g when viewed in a flowing-in direction from the inflow port 31g of the reservoir part 31 to the guide region 32i.SELECTED DRAWING: Figure 11

Description

[Technical field]

[0001] The present invention relates to a semiconductor device. [Background technology]

[0002] The cooling device has an object to be cooled placed on its front surface. The cooling device circulates a refrigerant inside to cool the object to be cooled (see, for example, Patent Documents 1 to 3). A semiconductor device includes such a cooling device and a semiconductor module, which is the object to be cooled, placed in the cooling device (see, for example, Patent Document 4). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2014-116404 A [Patent Document 2] JP 2017-174991 A [Patent Document 3] JP 2013-058518 A [Patent Document 4] International Publication No. 2012 / 147544 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present invention is to provide a semiconductor device that suppresses an increase in pressure loss of a refrigerant. [Means for solving the problem]

[0005] According to one aspect of the present invention, there is provided a storage section having a storage area defined by being surrounded by a rectangular bottom surface, a pair of long side surfaces and a pair of short side surfaces in a plan view, with an inlet provided on one of the short side surfaces; a guide section formed on the bottom surface, one end of which is connected to the inside of one of the short side surfaces and the other end of which is connected to one end of the one of the short side surfaces across the inlet, separating a guide area communicating with the inlet from the storage area outside the guide area; and a guide section disposed on the guide section with gaps from each of the pair of long side surfaces within the storage section, and extending from the one of the short side surfaces to the other in an area overlapping the guide area. and a heat sink including a flat guide plate having a slit formed therein extending toward one of the short sides of the semiconductor chip, a semiconductor chip, a front surface having a placement area defined thereon, a back surface having a cooling area defined thereon corresponding to the placement area, and a plurality of fins provided in the cooling area, the back surface being disposed on the storage portion, and the plurality of fins being stored in the storage area on the guide plate, wherein the guide portion is configured such that when viewed in an inflow direction from the inlet of the storage portion toward the guide area, the guide area of ​​the guide portion becomes smaller the further it is from the inlet.

[0006] In addition, the guide portion may include, in a planar view, a first guide wall extending from the one end toward the inflow direction and inclining toward a center line that passes through the center of the inlet and is parallel to the pair of long sides, a second guide wall extending from the other end toward the inflow direction and inclining toward the center line, and a tip wall connecting the inflow direction ends of the first guide wall and the second guide wall.

[0007] In addition, the guide portion may include, in a plan view, a first guide wall extending from the one end toward the inflow direction parallel to the pair of long sides, a second guide wall extending from the other end toward the inflow direction parallel to the pair of long sides, and a tip wall connecting the inflow direction ends of the first guide wall and the second guide wall, and the bottom surface of the guide area may be inclined so as to rise toward the guide plate as it moves away from the inlet.

[0008] The guide portion may be provided with a protrusion protruding toward the guide area in the vicinity of the inlet. The protrusions may be provided at positions facing the first guide wall and the second guide wall, respectively.

[0009] Moreover, the protrusion may be provided on the bottom surface within the guide area. In addition, the guide plate may have a pair of sub-slits formed on either side of the slit, the sub-slits being parallel to the slit, and the pair of sub-slits may extend from the inlet side to the protrusion in a plan view.

[0010] The pair of auxiliary slits may have a width of 1 mm or more and 4 mm or less. In addition, the guide portion may include, in a planar view, a first guide wall extending from the one end toward the inflow direction and inclining toward a center line that passes through the center of the inlet and is parallel to the pair of long sides, a second guide wall extending from the other end toward the inflow direction and inclining toward the center line, a third guide wall provided on the center line and extending from the inlet toward the inflow direction, and a tip wall connecting the inflow direction ends of the first guide wall and the second guide wall.

[0011] In addition, the guide plate may have the slits formed in a region overlapping the guide area sandwiched between the first guide wall and the third guide wall, and in a region overlapping the guide area sandwiched between the third guide wall and the second guide wall, when viewed in a plan view. An outlet may be formed on the other short side surface of the storage section, facing the inlet.

[0012] The above summary of the invention does not list all of the necessary features of the present invention. Also, subcombinations of these features may also be inventions. Effect of the Invention

[0013] According to the disclosed technology, it is possible to suppress an increase in pressure loss of the refrigerant, improve cooling performance, and suppress a decrease in reliability. [Brief description of the drawings]

[0014] [Figure 1] 1 is a plan view of a semiconductor device according to a first embodiment. [Diagram 2] 1 is a side view of a semiconductor device according to a first embodiment. [Diagram 3] FIG. 1 is an exploded perspective view of a cooling device according to a first embodiment. [Figure 4] FIG. 2 is a plan view of the cooling device (excluding a guide plate) of the first embodiment. [Diagram 5] 1 is a cross-sectional view of a cooling device (excluding a guide plate) according to a first embodiment. [Figure 6] FIG. 1 is a plan view of a cooling device according to a first embodiment. [Figure 7] 1 is a cross-sectional view of a cooling device according to a first embodiment. [Figure 8] FIG. 4 is a rear view of the heat sink according to the first embodiment. [Figure 9] 1 is a first cross-sectional view of a semiconductor device according to a first embodiment. [Figure 10] 4 is a second cross-sectional view of the semiconductor device according to the first embodiment. FIG. [Figure 11] FIG. 2 is a first plan view showing a flow of a refrigerant in the cooling device of the first embodiment. [Figure 12] 1 is a first cross-sectional view showing a flow of a refrigerant in a cooling device according to a first embodiment. FIG. [Figure 13] FIG. 4 is a second plan view showing the flow of a refrigerant in the cooling device of the first embodiment. [Figure 14] 4 is a second cross-sectional view showing the flow of refrigerant in the cooling device of the first embodiment. FIG. [Figure 15] FIG. 4 is a third plan view showing the flow of a refrigerant in the cooling device of the first embodiment. [Figure 16] FIG. 2 is a plan view of the cooling device (excluding the guide plate) of the reference example. [Figure 17] FIG. 2 is a plan view of a cooling device according to a reference example. [Figure 18] FIG. 11 is a plan view of a cooling device (excluding a guide plate) according to a second embodiment. [Figure 19] FIG. 11 is a cross-sectional view of a cooling device (excluding a guide plate) according to a second embodiment. [Figure 20] FIG. 11 is a plan view of a cooling device (excluding a guide plate) according to a third embodiment. [Figure 21] FIG. 11 is a cross-sectional view of a cooling device (excluding a guide plate) according to a third embodiment. [Figure 22] FIG. 13 is a plan view of a cooling device according to a third embodiment. [Figure 23] FIG. 13 is a cross-sectional view of a cooling device (excluding a guide plate) according to a fourth embodiment. [Figure 24] FIG. 13 is a plan view of a cooling device according to a fourth embodiment. [Diagram 25] FIG. 13 is a plan view of a cooling device (excluding a guide plate) according to a fifth embodiment. [Figure 26] FIG. 13 is a plan view of a cooling device according to a fifth embodiment. [Figure 27] 1 is a graph showing the temperature of a semiconductor chip versus the placement position of the semiconductor chip. [Figure 28] 1 is a graph showing pressure loss. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, the embodiment will be described with reference to the drawings. In the following description, the terms "front surface" and "upper surface" refer to the XY surface facing upward (+Z direction) in the semiconductor device 1 of the drawing. Similarly, "upper" refers to the upward (+Z direction) direction in the semiconductor device 1 of the drawing. The terms "rear surface" and "lower surface" refer to the XY surface facing downward (-Z direction) in the semiconductor device 1 of the drawing. Similarly, "lower" refers to the downward (-Z direction) direction in the semiconductor device 1 of the drawing. The same directionality as above will be used in other drawings as necessary. The terms "higher" and "upper" refer to the upper (+Z direction) position in the semiconductor device 1 of the drawing. Similarly, the terms "lower" and "lower" refer to the lower (-Z direction) position in the semiconductor device 1 of the drawing. The terms "front surface", "upper surface", "upper" and "rear surface", "lower surface", "lower" and "side surface" are merely convenient expressions for specifying relative positional relationships, and do not limit the technical idea of ​​the present invention. For example, "up" and "down" do not necessarily mean the vertical direction relative to the ground. In other words, the directions of "up" and "down" are not limited to the direction of gravity. In the following explanation, "main component" refers to a component containing 80 vol% or more. "Approximately the same" means within a range of ±10%. "Vertical", "orthogonal", and "parallel" mean within a range of ±10°. [First embodiment]

[0016] The semiconductor device will be described with reference to Fig. 1 and Fig. 2. Fig. 1 is a plan view of the semiconductor device of the first embodiment. Fig. 2 is a side view of the semiconductor device of the first embodiment. Fig. 2 is a side view of the semiconductor device 1 of Fig. 1 as viewed in the +Y direction.

[0017] As shown in Fig. 1 and Fig. 2, the semiconductor device 1 includes a semiconductor unit 2, a heat sink 15, and a cooling device 3. The semiconductor unit 2 includes insulating circuit boards 10a, 10b, and 10c, and semiconductor chips 14 arranged on the front surfaces of the insulating circuit boards 10a, 10b, and 10c via bonding members 16. The insulating circuit boards 10a, 10b, and 10c include insulating plates 11a, 11b, and 11c, conductive patterns 12a, 12b, and 12c provided on the front surfaces of the insulating plates 11a, 11b, and 11c, and metal plates 13a, 13b, and 13c provided on the back surfaces of the insulating plates 11a, 11b, and 11c. In the following description, the insulating circuit boards 10a, 10b, and 10c are referred to as the insulating circuit board 10 when there is no need to distinguish between them. Even when the insulating plates 11a, 11b, and 11c, the conductive patterns 12a, 12b, and 12c, and the metal plates 13a, 13b, and 13c are not distinguished from one another, they are similarly referred to as the insulating plate 11, the conductive pattern 12, and the metal plate 13.

[0018] The insulating plate 11 and the metal plate 13 are rectangular in plan view. The corners of the insulating plate 11 and the metal plate 13 may be rounded or chamfered. The size of the metal plate 13 is smaller than the size of the insulating plate 11 in plan view, and is formed inside the insulating plate 11.

[0019] The insulating plate 11 may be, for example, a ceramic substrate. The ceramic substrate is made of ceramics with good thermal conductivity. The ceramics is made of a material containing aluminum oxide, aluminum nitride, or silicon nitride as a main component. The insulating plate 11 has a rectangular shape in a plan view.

[0020] The conductive pattern 12 is formed over the entire surface of the insulating plate 11 except for the edge portion. Preferably, in a plan view, the end of the conductive pattern 12 facing the outer periphery of the insulating plate 11 overlaps the end of the metal plate 13 on the outer periphery side. Therefore, the insulating circuit board 10 maintains a stress balance with the metal plate 13 on the back surface of the insulating plate 11. Damage such as excessive warping and cracking of the insulating plate 11 is suppressed. The conductive pattern 12 is made of a material with excellent conductivity. Examples of such materials include copper, aluminum, and alloys containing at least one of these. It is also possible to plate the conductive pattern 12 with a material with excellent corrosion resistance. Examples of such materials are nickel, nickel-phosphorus alloy, and nickel-boron alloy. The conductive pattern 12 for the insulating plate 11 is obtained by forming a metal plate on the front surface of the insulating plate 11 and performing a process such as etching on the metal plate. Alternatively, the conductive pattern 12 cut out in advance from a metal plate may be pressure-bonded to the front surface of the insulating plate 11. The conductive patterns 12 included in the semiconductor device 1 of the present embodiment are merely an example. The number, shape, size, and the like of the conductive patterns may be appropriately selected as necessary.

[0021] The metal plate 13 is made of a metal having excellent thermal conductivity. Examples of such materials include copper, aluminum, or an alloy containing at least one of these. Here, copper is included. In addition, in order to improve corrosion resistance, a plating process may be performed on the surface of the metal plate 13. In this case, the plating material contains nickel. Such a plating material is, for example, nickel, a nickel-phosphorus alloy, or a nickel-boron alloy.

[0022] For example, a DCB (Direct Copper Bonding) board or an AMB (Active Metal Brazed) board may be used as the insulating circuit board 10 having such a configuration. The insulating circuit board 10 dissipates heat generated in a semiconductor chip 14 (described later) by conducting it to the back side of the insulating circuit board 10 via the conductive pattern 12, the insulating plate 11, and the metal plate 13.

[0023] The semiconductor chip 14 includes a switching element mainly made of silicon, for example. The switching element is, for example, an RC (Reverse-Conducting)-IGBT (Insulated Gate Bipolar Transistor). The RC-IGBT is a circuit in which an IGBT and an FWD (Free Wheeling Diode) are connected in reverse parallel, and the circuit is configured within one chip.

[0024] The semiconductor chip 14 has a collector electrode as an input electrode on the back surface, and a gate electrode as a control electrode 14b and an emitter electrode as an output electrode 14a on the front surface. The control electrode 14b may be provided at the center of one side of the front surface of the semiconductor chip 14. Alternatively, the control electrode 14b does not necessarily have to be provided at the center of one side of the front surface of the semiconductor chip 14, and may be shifted in the ±X direction from the center.

[0025] Another switching element may be a power MOSFET (Metal Oxide Semiconductor Field Effect Transistor) mainly composed of silicon carbide. In the power MOSFET, the body diode functions as the FWD. Such a semiconductor chip 14 has, for example, a drain electrode as an input electrode on the back surface, and a gate electrode as a control electrode 14b and a source electrode as an output electrode 14a on the front surface.

[0026] Also, instead of the semiconductor chip 14, a semiconductor chip mainly composed of silicon and including a pair of switching elements and diode elements may be used. The switching elements are, for example, power MOSFETs and IGBTs. The semiconductor chip including the switching elements includes, for example, an input electrode (drain electrode in a power MOSFET, collector electrode in an IGBT) on the back surface, and a control electrode 14b (gate electrode) and an output electrode 14a (source electrode in a power MOSFET, emitter electrode in an IGBT) on the front surface. The diode elements include, for example, SBD (Schottky Barrier Diode) and PiN (P-intrinsic-N) diodes as FWDs. The semiconductor chip including the diode elements includes an output electrode (cathode electrode) as a main electrode on the back surface, and an input electrode (anode electrode) as a main electrode on the front surface.

[0027] The semiconductor chip 14 has its back surface joined to the conductive pattern 12 by a joining member 16. The joining member 16 is a solder or a sintered body. The solder is made of a lead-free solder mainly composed of a predetermined alloy. The predetermined alloy contains tin. Such an alloy is, for example, at least one of an alloy of tin-silver-copper, an alloy of tin-zinc-bismuth, an alloy of tin-copper, an alloy of tin-silver-indium-bismuth, and an alloy of tin-antimony. The solder may contain an additive. Examples of the additive include nickel, germanium, cobalt, and silicon. In addition, the sintering material when joining by sintering is, for example, a powder of silver, iron, copper, aluminum, titanium, nickel, tungsten, or molybdenum.

[0028] The heat sink 15 includes a rectangular front surface 15e in a plan view, a back surface 15f opposite to the front surface 15e, and long side surfaces 15a, short side surfaces 15b, long side surfaces 15c, and short side surfaces 15d surrounding the front surface 15e and the back surface 15f in that order. The front surface 15e of the heat sink 15 has a unit area 15e1 in which the semiconductor units 2 are arranged. The insulating circuit boards 10a, 10b, and 10c of the semiconductor units 2 are arranged in a row along the long side surfaces 15a and 15c in the unit area 15e1 of the front surface 15e. At this time, the metal plate 13 of the insulating circuit board 10 is joined to the front surface 15e by the joining member 16 described above. The heat sink 15 is made of a metal with excellent thermal conductivity. Examples of such materials include copper, aluminum, or an alloy containing at least one of these. Here, copper is included. In order to improve corrosion resistance, the surface of the heat sink 15 may be plated. In this case, the plating material contains nickel. Such plating material is, for example, nickel, a nickel-phosphorus alloy, or a nickel-boron alloy. Details of the heat sink 15 will be described later.

[0029] In this embodiment, the semiconductor units 2 are arranged on the heat sink 15, so that six semiconductor chips 14 are arranged in a row along the long sides 15a, 15c of the heat sink 15. These semiconductor chips 14 are identified as (a) to (f) in order from the outlet 30h described later.

[0030] The cooling device 3 is provided on the back side of the heat sink 15. The cooling device 3 includes a housing 30. The housing 30 is disposed opposite the heat sink 15 in a plan view, and includes a rectangular bottom plate 30f and a long side wall 30a, a short side wall 30b, a long side wall 30c, and a short side wall 30d that surround the bottom plate 30f on all four sides (see FIG. 3). The long side wall 30a, the short side wall 30b, the long side wall 30c, and the short side wall 30d have the same height. The back side 15f of the heat sink 15 is attached to the top of the long side wall 30a, the short side wall 30b, the long side wall 30c, and the short side wall 30d. In addition, the edges of the long side wall 30a, the short side wall 30b, the long side wall 30c, and the short side wall 30d in the +Z direction may be turned outward. This increases the area bonded to the rear surface 15f of the heat sink 15, improving adhesion to the rear surface 15f of the heat sink 15. An inlet 30g is formed in the short side wall 30b. An outlet 30h is formed in the short side wall 30d. The inlet 30g and the outlet 30h communicate with the inside of the housing 30.

[0031] Such a cooling device 3 may include a pump and a heat dissipation device (radiator). The pump introduces a refrigerant into an inlet 30g of the cooling device 3, and the refrigerant that has flowed in from the inlet 30g flows through the cooling device 3. The refrigerant acquires heat from the semiconductor unit 2 while flowing through the cooling device 3. The refrigerant that has flowed through the cooling device 3 flows out from an outlet 30h. The heat dissipation device receives the refrigerant that has flowed out from the cooling device 3 and dissipates heat contained in the refrigerant from the semiconductor unit 2 to the outside. The pump causes the refrigerant that has dissipated heat to flow again into the cooling device 3 from the inlet 30g and circulates. For example, water, antifreeze (ethylene glycol aqueous solution), or long-life coolant is used as the refrigerant. Details of the cooling device 3 will be described later.

[0032] The front surface 15e of the heat sink 15 of the semiconductor device 1 may be provided with a case (not shown) for housing the semiconductor unit 2. The case is integrally formed with, for example, an N-type terminal, a P-type terminal, and an output terminal. Inside the case, these terminals are connected to the semiconductor unit 2. Inside the semiconductor unit 2, the semiconductor unit 2 and various terminals may be connected by wiring members (not shown). Examples of the wiring members include wires and lead frames. The case is molded by injection molding using a thermoplastic resin containing a filler. Examples of such resin include polyphenylene sulfide (PPS) resin, polybutylene terephthalate (PBT) resin, and polyamide (PA) resin. The filler is composed of, for example, glass fiber, glass beads, calcium carbide, talc, magnesium oxide, and aluminum hydroxide.

[0033] The inside of the case may be sealed with a sealing member. The sealing member is, for example, a thermosetting resin mixed with a filler. The thermosetting resin is, for example, an epoxy resin, a phenol resin, a maleimide resin, or a polyester resin. The filler is a ceramic having insulating properties and high thermal conductivity. Such a filler is, for example, silicon oxide, aluminum oxide, boron nitride, or aluminum nitride.

[0034] Next, the cooling device 3 will be described with reference to Figs. 3 to 10. Fig. 3 is an exploded perspective view of the cooling device of the first embodiment. Fig. 4 is a plan view of the cooling device of the first embodiment (excluding the guide plate), and Fig. 5 is a cross-sectional view of the cooling device of the first embodiment (excluding the guide plate). Fig. 6 is a plan view of the cooling device of the first embodiment, and Fig. 7 is a cross-sectional view of the cooling device of the first embodiment. Fig. 8 is a rear view of the heat sink of the first embodiment. Fig. 9 is a first cross-sectional view of the semiconductor device of the first embodiment, and Fig. 10 is a second cross-sectional view of the semiconductor device of the first embodiment.

[0035] Fig. 5 is a cross-sectional view taken along dashed line YY in Fig. 4. Fig. 7 is a cross-sectional view taken along dashed line YY in Fig. 6. Fig. 9 is a cross-sectional view taken along dashed line YY in Fig. 1. Fig. 10 is a cross-sectional view taken along dashed line XX in Figs. 1 and 2.

[0036] 3, the cooling device 3 includes the housing 30 described above, a guide portion 32 included in the housing 30, and a guide plate 33 provided on the guide portion 32. As described above, the housing 30 includes a bottom plate 30f, a long side wall 30a, a short side wall 30b, a long side wall 30c, and a short side wall 30d, which enclose the storage area 30i.

[0037] As shown in FIG. 4 and FIG. 5, the housing 30 includes a storage section 31 in the storage area 30i. The storage section 31 is in the storage area 30i, and a long side wall 31a, a short side wall 31b, a long side wall 31c, and a short side wall 31d are formed on the bottom plate 30f. The long side wall 31a, the short side wall 31b, the long side wall 31c, and the short side wall 31d are formed on the bottom plate 30f so as to form a rectangular shape in a plan view, thereby defining the storage area 31i. The connection points between the long side wall 31a, the short side wall 31b, the long side wall 31c, and the short side wall 31d may form an R surface. Similarly, the connection points between the long side wall 31a, the short side wall 31b, the long side wall 31c, and the short side wall 31d with respect to the bottom plate 30f may also form an R surface. As a result, as will be described later, the coolant flowing through storage portion 31 is prevented from stagnating at the corners contained within storage portion 31, and is more likely to flow smoothly.

[0038] The long side wall 31a, the short side wall 31b, the long side wall 31c, and the short side wall 31d of the storage section 31 face the long side wall 30a, the short side wall 30b, the long side wall 30c, and the short side wall 30d of the housing 30, respectively. The storage area 31i is located at the center of the storage area 30i in the ±X direction and the ±Y direction in a plan view. The long side wall 31a, the short side wall 31b, the long side wall 31c, and the short side wall 31d of the storage section 31 are equal in height. The long side wall 31a, the short side wall 31b, the long side wall 31c, and the short side wall 31d of the storage section 31 are equal in height to the long side wall 30a, the short side wall 30b, the long side wall 30c, and the short side wall 30d of the housing 30.

[0039] The outside of the storage area 31i of the housing 30 and the inside of the storage area 30i may be sealed with a sealing member. Alternatively, the entire housing 30 may be made of a sealing member in a block shape, and a space corresponding to the storage area 31i may be opened inside the block.

[0040] An inlet 31g and an outlet 31h are formed in the short side walls 31b, 31d of the storage section 31. The inlet 31g and the outlet 31h are connected to a guide area 32i and a storage area 31i, respectively, which will be described later. The inlet 31g and the outlet 31h are arranged in a straight line in the ±X direction with respect to the inlet 30g and the outlet 30h of the housing 30. That is, the inlets 30g, 31g and the outlets 30h, 31h face each other.

[0041] The inlets 30g, 31g and the outlets 30h, 31h may be, for example, circular. The inlets 30g, 31g and the outlets 30h, 31h may have the same diameter. The diameters of the inlets 30g, 31g and the outlets 30h, 31h may be, for example, 20% or more and 70% or less of the width of the short side walls 31b, 31d of the storage section 31 in the ±Y direction.

[0042] The inlets 30g, 31g and the outlets 30h, 31h are located at the center of the height of a guide region 32i (described later) in the ±Z direction. Therefore, the inlets 30g, 31g and the outlets 30h, 31h are formed in the short side walls 30b, 30d of the housing 30 and the short side walls 31b, 31d of the storage section 31, respectively, in correspondence with these positions.

[0043] The inlets 30g and 31g are connected by an inlet passage 30j. The outlets 30h and 31h are connected by an outlet passage 30k. The inlet passage 30j and the outlet passage 30k are also in a straight line. The inlet passage 30j and the outlet passage 30k may be cylindrical, and the entire inner surface may be substantially flat without any irregularities.

[0044] The location where the outlets 30h, 31h are formed is not limited to the short side walls 30d, 31d. For example, the outlets 30h, 31h may be formed in the bottom plate 30f on the tip (-X direction) side of the tip wall 32d of the guide portion 32 described later in the storage area 31i. In this case, the outlet path 30k penetrates from the bottom plate 30f in the ±Z direction. Alternatively, the outlet 31h may be formed in the short side wall 31d opposite to the inlet 31g, and the outlet 30h may be formed in the bottom plate 30f in the storage area 30i outside the storage area 31i. In this case, the outlet path 30k may connect the outlets 30h, 31h in the storage area 30i. The location where the inlets 30g, 31g are formed is not limited to the short side walls 30b, 31b. For example, the inlets 30g, 31g may be formed in the bottom plate 30f on the short side wall 31b side of the guide region 32i described later. In this case, the inlet passage 30j penetrates from the bottom plate 30f in the ±Z direction. Alternatively, the inlet 31g may be formed in the short side wall 31b opposite the outlet 31h, and the inlet 30g may be formed in the bottom plate 30f in the storage region 30i outside the storage region 31i. In this case, the inlet passage 30j may connect the inlets 30g, 31g in the storage region 30i.

[0045] As shown in Figs. 3 to 5, the guide portion 32 is provided on the bottom plate 30f in the storage area 31i of the storage portion 31. The guide portion 32 includes a guide wall 32a, a tip wall 32d, and a guide wall 32c that are integrally connected, and includes one end and the other end. The one end is included in the guide wall 32a and is connected to the short side wall 31b of the storage portion 31. The other end is included in the guide wall 32c and is connected to the short side wall 31b of the storage portion 31. The lower ends (-Z direction) of the guide wall 32a, the tip wall 32d, and the guide wall 32c are connected to the bottom plate 30f. The connection points of the guide wall 32a, the tip wall 32d, and the guide wall 32c may form an R surface. Similarly, the connection points of the guide wall 32a, the tip wall 32d, and the guide wall 32c to the bottom plate 30f may also form an R surface. As a result, as will be described later, the coolant flowing through the guide portion 32 is prevented from stagnating at the corners contained within the guide portion 32, and is more likely to flow smoothly.

[0046] The heights (±Z direction) of guide wall 32a, tip wall 32d, and guide wall 32c are equal. The heights (±Z direction) of guide wall 32a, tip wall 32d, and guide wall 32c are smaller than the heights of housing 30 and storage section 31, and may be, for example, about 50% of these heights. Furthermore, the inner surfaces of guide wall 32a, tip wall 32d, and guide wall 32c may be substantially flat without including irregularities.

[0047] One end of the guide wall 32a is connected to the inside of the short side wall 31b included in the storage section 31. Here, one end of the guide wall 32a is connected to the side of the inlet 31g of the short side wall 31b in a plan view. The guide wall 32a extends from one end toward the short side wall 31d. In this case, as the guide wall 32a extends toward the short side wall 31d, it is inclined toward (approaching) a center line (in FIG. 4, the dashed dotted line YY corresponds to the center line) that passes through the centers of the short side walls 31b, 31d and is parallel to the long side walls 31a, 31c in a plan view.

[0048] The other end of the guide wall 32c is also connected to the inside of the short side wall 31b of the storage section 31. Here, the other end of the guide wall 32c is connected to the short side wall 31b on the opposite side to one end of the guide wall 32a across the inlet 31g. That is, the other end of the guide wall 32c is connected to the side of the short side wall 31b on the opposite side to one end of the guide wall 32a across the inlet 31g. The guide wall 32c extends from the other end toward the short side wall 31d. At this time, as the guide wall 32c extends toward the short side wall 31d, it is inclined toward (approaching) the center line (in FIG. 4, the dashed line YY corresponds to the center line).

[0049] The tip wall 32d is connected to the tips (-X direction) of the guide walls 32a and 32c. The tip wall 32d faces the short side wall 31d of the storage section 31. That is, the tip wall 32d is parallel to the short side wall 31d of the storage section 31. The tip wall 32d is disposed with a gap from the short side wall 31d of the storage section 31. The tip wall 32d is located in the center of the short side walls 31b and 31d of the storage section 31 in the ±Y direction in a plan view. The width of the tip wall 32d in a plan view (in the ±Y direction) is smaller than the length from the part where one end of the guide wall 32a of the short side wall 31b is connected to the part where the other end of the guide wall 32c is connected to. Furthermore, the width of the tip wall 32d in a plan view (in the ±Y direction) is smaller than the diameter of the inlet 31g.

[0050] An inlet 32b is defined between one end of guide wall 32a and the other end of guide wall 32c of guide portion 32. The width (±Y direction) of inlet 32b may be approximately the diameter of inlet 31g and is larger than inlet 31g.

[0051] The guide portion 32 is provided in the storage portion 31 in this manner, thereby forming a guide region 32i surrounded by the guide portion 32 and the short side wall 31b. The guide portion 32 also defines the guide region 32i and the storage region 31i outside the guide region 32i. The inlet 32b of the guide portion 32 is connected to the guide region 32i. Therefore, the inlet 30g passes through the inflow path 30j and the inlets 31g and 32b and is connected to the guide region 32i.

[0052] As shown in Figs. 3, 6 and 7, the guide plate 33 has a flat shape and includes a rectangular front surface 33e in a plan view, a back surface 33f opposite the front surface 33e, and a long side surface 33a, a short side surface 33b, a long side surface 33c and a short side surface 33d surrounding the front surface 33e on all four sides. The guide plate 33 is disposed on the guide section 32 in the storage section 31. The length of the long sides 33a and 33c of the guide plate 33 in the ±X direction is the same as the length of the storage section 31 in the same direction. The width of the short sides 33b and 33d of the guide plate 33 in the ±Y direction is smaller than the width of the storage section 31 in the same direction. When such a guide plate 33 is disposed on the guide section 32, first and second recovery gaps 33h and 33i are formed between the long sides 33a and 33c of the guide plate 33 and the long side walls 31a and 31c of the storage section 31 in a plan view. The width of the first and second recovery gaps 33h, 33i in the ±Y directions may be, for example, 1 mm.

[0053] The guide plate 33 is formed with a guide slit 33g penetrating from the front surface 33e to the back surface 33f. When the guide plate 33 is placed on the guide section 32, the guide slit 33g overlaps with the guide area 32i in a plan view, and extends in a straight line from the inlet 32b toward the tip wall 32d to just before the tip wall 32d, and is formed in the guide plate 33. When the guide plate 33 is placed on the guide section 32, the guide slit 33g is formed on a center line (corresponding to the dashed line YY in FIG. 6) passing through the center of the inlet 32b and the tip wall 32d of the guide section 32 of the guide plate 33 in a plan view. The width (±Y direction) of the guide slit 33g is not less than one-sixth and not more than one-fifth of the width of the inlet 32b in the same direction in a plan view. In the case of the first embodiment, the width of the guide slit 33g is, for example, not less than 2 mm and not more than 4 mm, and may be specifically 2 mm.

[0054] The guide area 32i surrounded by the guide part 32, the bottom plate 30f, and the guide plate 33 becomes smaller as it moves away from the inlet 32b when viewed in the inflow direction from the inlet 32b of the storage part 31 toward the guide area 32i. The guide part 32 and the bottom plate 30f are formed so as to form the guide area 32i.

[0055] Next, the heat sink 15 to which the cooling device 3 is joined on the back surface 15f will be described. As described above, the heat sink 15 includes a rectangular front surface 15e, a back surface 15f, a long side surface 15a, a short side surface 15b, a long side surface 15c, and a short side surface 15d in a plan view. As shown in FIG. 8, the heat sink 15 has a plurality of fins 15g formed in a range (cooling area 15f1) of the back surface 15f facing the unit area 15e1 of the front surface 15e. The fins 15g are columnar. The columnar shape may be a circular cylinder or a rectangular column. The plurality of fins 15g are formed perpendicular to the back surface 15f of the heat sink 15.

[0056] Such a heat sink 15 has the semiconductor unit 2 disposed on the front surface 15e, and is disposed in the housing 30 as shown in Figures 9 and 10. At this time, the back surface 15f of the heat sink 15 is disposed on the storage section 31, and the multiple fins 15g of the heat sink 15 are stored in the storage area 31i on the guide plate 33 in the storage section 31. That is, the multiple fins 15g of the heat sink 15 are surrounded on the back surface side (-Z direction side) by the guide plate 33, and on all four sides by the long side wall 31a, the short side wall 31b, the long side wall 31c, and the short side wall 31d, in that order.

[0057] Next, the flow of the refrigerant in the cooling device 3 will be described with reference to Figs. 11 to 15. Fig. 11 is a first plan view showing the flow of the refrigerant in the cooling device of the first embodiment, and Fig. 12 is a first cross-sectional view showing the flow of the refrigerant in the cooling device of the first embodiment. Fig. 13 is a second plan view showing the flow of the refrigerant in the cooling device of the first embodiment, and Fig. 14 is a second cross-sectional view showing the flow of the refrigerant in the cooling device of the first embodiment. Fig. 15 is a third plan view showing the flow of the refrigerant in the cooling device of the first embodiment.

[0058] In the above figures, the flow of the refrigerant is indicated by dashed arrows. In addition, in the above figures, heat sink 15 and guide plate 33 are omitted as necessary for the explanation of the flow of the refrigerant. Also, Fig. 12 is a cross-sectional view taken along dashed line YY in Fig. 11. Fig. 14 is a perspective side view of Fig. 13 as viewed in the -X direction.

[0059] First, the refrigerant is pumped into the cooling device 3 through the inlet 30g. The refrigerant that has flowed in through the inlet 30g passes through the inlet 30j, enters the guide area 32i through the inlets 31g and 32b, and travels straight in the -X direction, as shown in Figures 11 and 12. When the refrigerant fills the guide area 32i to a certain extent, the refrigerant flows out of the guide plate 33 through the guide slit 33g of the guide plate 33.

[0060] The guide area 32i becomes smaller as it moves away from the inlet 32b when viewed in the inflow direction from the inlet 32b toward the guide area 32i. Therefore, the pressure difference between the tip wall 32d side and the inlet 32b side of the refrigerant that has entered the guide area 32i becomes smaller, and the refrigerant easily flows out from the vicinity of the inlet 32b of the guide slit 33g. Therefore, the refrigerant that has flowed into the guide area 32i flows out almost uniformly from the entire guide slit 33g.

[0061] The refrigerant that has flowed from the guide slits 33g into the storage area 31i on the guide plate 33 flows between the multiple fins 15g toward the first and second recovery gaps 33h, 33i on the long side surfaces 33a, 33c of the guide plate 33, as shown in Fig. 13. The refrigerant flowing between the multiple fins 15g receives heat that has been conducted from the semiconductor unit 2 through the heat sink 15 and the multiple fins 15g.

[0062] The refrigerant flowing from the guide slit 33g toward the first and second recovery gaps 33h, 33i flows from the first and second recovery gaps 33h, 33i into the storage area 31i surrounded by the guide plate 33, the long side wall 31a, the short side wall 31b, the long side wall 31c, and the short side wall 31d, as shown in FIG. 14.

[0063] The refrigerant thus flowing into the storage area 31i below the guide plate 33 flows through the storage area 31i outside the guide area 32i toward the outlet 30h, and flows out from the outlet 30h, as shown in FIG.

[0064] The heat dissipation device receives the refrigerant flowing out of the cooling device 3 in this manner, and dissipates the heat contained in the refrigerant to the outside. The pump causes the refrigerant from which the heat has been dissipated to flow again into the cooling device 3 from the inlet 30g, thereby causing the refrigerant to circulate.

[0065] Here, the cooling device of the reference example will be described with reference to Fig. 16 and Fig. 17. Fig. 16 is a plan view of the cooling device of the reference example (excluding the guide plate). Fig. 17 is a plan view of the cooling device of the reference example. Fig. 16 shows a plan view of the cooling device 300 excluding the guide plate 33.

[0066] The cooling device 300 of the reference example differs from the cooling device 3 of the first embodiment in the guide portion 32. The guide portion 32 of the cooling device 300 has a guide wall 32a, a tip wall 32d, and a guide wall 32c that are integrally connected. However, in the reference example, as shown in FIG. 16, the guide walls 32a and 32c are provided parallel to the long side walls 31a and 31c of the storage portion 31. In addition, in the reference example, the tip wall 32d connects the tip sides (-X direction) of such guide walls 32a and 32c. This tip wall 32d forms an arc shape that bulges toward the short side wall 31d.

[0067] Similarly to the first embodiment, when the guide plate 33 is placed on the guide section 32, first and second recovery gaps 33h, 33i are formed between the long side surfaces 33a, 33c of the guide plate 33 and the long side walls 31a, 31c of the storage section 31 in a plan view. Furthermore, as shown in Fig. 17, when the guide plate 33 is placed on the guide section 32, the guide slit 33g is also formed on a center line (corresponding to the dashed line YY in Fig. 17) passing through the inlet 32b of the guide section 32 of the guide plate 33 and the center of the tip wall 32d in a plan view. In this reference example, the guide area 32i surrounded by the bottom plate 30f, the guide section 32, and the guide plate 33 is substantially cubic.

[0068] When the refrigerant flows into the cooling device 300 from the inlet 30g, it passes through the inlet 30j and enters the guide area 32i from the inlets 31g and 32b, as in the first embodiment. When the refrigerant fills the guide area 32i to a certain extent, the refrigerant flows out of the guide plate 33 from the guide slit 33g of the guide plate 33.

[0069] In this case, if the width of the guide slit 33g is narrow (for example, about 1 mm), the refrigerant can flow out uniformly from the entire guide slit 33g. However, if the guide slit 33g is narrow, the pressure loss of the refrigerant increases. This, for example, increases the driving cost of the pump.

[0070] On the other hand, if the guide slit 33g has a large width (for example, about 2 mm), the refrigerant cannot flow out uniformly from the entire guide slit 33g.

[0071] In the reference example, the guide region 32i hardly changes even when moving away from the inlet 32b when viewed in the inflow direction from the inlet 31g (inlet 32b) of the storage section 31 toward the guide region 32i. The pressure of the refrigerant flowing into the guide region 32i increases as it approaches the tip wall 32d of the guide region 32i. In a plan view, the flow speed of the refrigerant is slower on the inlet 32b side of the guide slit 33g than on the tip wall 32d side.

[0072] Therefore, the flow rate of the coolant flowing out of the guide slit 33g is greater on the tip wall 32d side than on the inlet 32b side. As a result, the heat dissipation on the front surface 15e of the heat sink 15 is biased depending on the position. That is, the heat dissipation on the front surface 15e of the heat sink 15 is lower on the inlet 30g (inlet 32b) side than on the outlet 30h (tip wall 32d) side. Accordingly, the heat dissipation from the front surface 15e of the heat sink 15 to the semiconductor chip 14 included in the semiconductor unit 2 is also non-uniform. If the heat dissipation of the semiconductor unit 2 is non-uniform, the reliability of the semiconductor device 1 is reduced. Details of the heat dissipation will be described later.

[0073] Therefore, the semiconductor device 1 of the first embodiment includes a semiconductor chip 14, a heat sink 15, and a cooling device 3. The heat sink 15 includes a front surface 15e on which a unit area 15e1 in which the semiconductor chip 14 is arranged is defined, a back surface 15f on which a cooling area 15f1 corresponding to the unit area 15e1 is defined, and a plurality of fins 15g provided in the cooling area 15f1.

[0074] The cooling device 3 is provided on the rear surface 15f of the heat sink 15, and includes a storage section 31, a guide section 32, and a guide plate 33. The storage section 31 has a storage area 31i surrounded and defined by a bottom plate 30f having a rectangular shape in a plan view, a pair of long side walls 31a, 31c, and a pair of short side walls 31b, 31d, and an inlet 31g is provided in one of the short side walls 31b.

[0075] The guide portion 32 has one end connected to the inside of the short side wall 31b and the other end connected to the same end of the short side wall 31b across the inlet 31g, and is formed on the bottom plate 30f, separating the guide area 32i leading to the inlet 31g from the storage area 31i outside the guide area 32i.

[0076] The guide plate 33 is arranged on the guide section 32 within the storage area 31i with first and second recovery gaps 33h, 33i spaced apart from the long side walls 31a, 31c, respectively, and is in the form of a flat plate with a guide slit 33g extending from the short side wall 31b toward the short side wall 31d formed in the area overlapping with the guide area 32i.

[0077] When the cooling device 3 is attached to the rear surface 15f of the heat sink 15, the multiple fins 15g are stored in the storage area 31i on the guide plate 33. In such a cooling device 3, the guide section 32 is further configured such that, when viewed in the inflow direction from the inlet 31g of the storage section 31 toward the guide area 32i, the guide area 32i of the guide section 32 becomes smaller with increasing distance from the inlet 31g.

[0078] Therefore, the pressure difference between the tip wall 32d side and the inlet 32b side for the refrigerant that has entered the guide area 32i becomes small, and the refrigerant easily flows out from the vicinity of the inlet 32b of the guide slit 33g. Therefore, the refrigerant that has flowed into the guide area 32i flows out almost uniformly from the entire guide slit 33g. Therefore, the variation in heat dissipation due to the position on the front surface 15e of the heat sink 15 becomes small, the semiconductor unit 2 can be uniformly cooled, the pump driving cost can be reduced by suppressing the pressure loss, and the deterioration of the reliability of the semiconductor device 1 can be suppressed.

[0079] [Second embodiment] Guide portion 32 needs to be configured such that guide area 32i surrounded by guide portion 32, bottom plate 30f, and guide plate 33 becomes smaller as it moves away from inlet 31g when viewed in the inflow direction from inlet 31g of storage portion 31 toward guide area 32i. The first embodiment is a case in which guide walls 32a, 32c of guide portion 32 are inclined so as to approach the center lines of short side walls 31b, 31d as they move from short side wall 31b toward short side wall 31d.

[0080] The cooling device of the second embodiment will be described with reference to Figs. 18 and 19. Fig. 18 is a plan view of the cooling device of the second embodiment (excluding the guide plate). Fig. 19 is a cross-sectional view of the cooling device of the second embodiment (excluding the guide plate). Fig. 19 is a cross-sectional view taken along dashed line YY in Fig. 18.

[0081] The guide portion 32 of the second embodiment has a guide wall 32a, a tip wall 32d, and a guide wall 32c that are integrally connected to each other, and includes one end and the other end, which are also connected to the short side wall 31b with the inlet 31g interposed therebetween, as in the first embodiment.

[0082] However, in the second embodiment, as shown in Fig. 18, the guide walls 32a, 32c extend from the short side wall 31b toward the short side wall 31d in parallel with the long side walls 31a, 31c. The tip wall 32d integrally connects the tips (-X direction) of the long side walls 31a, 31c. In Fig. 18, the connection points between the tip wall 32d and the long side walls 31a, 31c form a right angle. The connection points may be R-chamfered or C-chamfered. Also, the tip wall 32d may be formed in an arc shape as shown in Fig. 16.

[0083] In addition, in the second embodiment, a guide portion 32 is formed on the bottom plate 30f, and the bottom surface 32f surrounded by the guide portion 32 is inclined upward (toward the +Z side) as it moves from the short side wall 31b toward the short side wall 31d.

[0084] As a result, the guide area 32i surrounded by the guide portion 32, the bottom surface 32f, and the guide plate 33 (not shown here) becomes smaller as it moves away from the inlet 31g when viewed in the inflow direction from the inlet 31g of the storage portion 31 toward the guide area 32i.

[0085] In the case of the guide portion 32 forming the guide region 32i, as in the first embodiment, the pressure difference between the outlet 30h (tip wall 32d) side and the inlet 32b side is small for the coolant that has entered the guide region 32i, and the coolant is more likely to flow out from the vicinity of the inlet 32b of the guide slit 33g. Therefore, the coolant that has flowed into the guide region 32i flows out almost uniformly from the entire guide slit 33g. Therefore, the variation in heat dissipation due to the position of the front surface 15e of the heat sink 15 is reduced, the semiconductor unit 2 can be uniformly cooled, the pump driving cost can be reduced by suppressing the pressure loss, and the deterioration of the reliability of the semiconductor device 1 can be suppressed.

[0086] [Third embodiment] The cooling device of the third embodiment will be described with reference to Figs. 20 to 22. Fig. 20 is a plan view of the cooling device of the third embodiment (excluding the guide plate), and Fig. 21 is a cross-sectional view of the cooling device of the third embodiment (excluding the guide plate). Fig. 22 is a plan view of the cooling device of the third embodiment. Fig. 21 is a cross-sectional view taken along dashed line YY in Fig. 20.

[0087] In the cooling device 3 of the third embodiment, protrusions 32g are formed at positions facing the guide walls 32a and 32c included in the guide portion 32 of the cooling device 3 of the first embodiment. The protrusions 32g are formed on the inlet 31g side in a plan view.

[0088] Such a protrusion 32g may be formed within 30% of the length of the guide walls 32a and 32c from the inlet 31g. The protrusion 32g may protrude into the guide region 32i within a range that does not interfere with the flow of the refrigerant, and may protrude even slightly. As shown in FIG. 21, the protrusion 32g may be rod-shaped in side view and formed parallel to the ±Z direction from the lower end to the upper end of the guide walls 32a and 32c. The protrusion 32g may be inclined at an obtuse angle with respect to the bottom plate 30f. That is, the protrusion 32g may be inclined so that its upper end approaches the outlet 31h (tip wall 32d). The protrusion 32g may be, for example, semicircular, triangular, or rectangular in plan view. FIG. 20 shows a semicircular shape.

[0089] 22, the guide plate 33 has sub-slits 33g1 formed on both sides (long side surfaces 33a, 33c sides) of the guide slit 33g, in a range sandwiched between the guide walls 32a, 32c in a plan view. The sub-slits 33g1 extend from the short side wall 31b toward the short side wall 31d to the protrusion 32g in parallel with the guide slit 33g. The width of the sub-slits 33g1 in the ±Y direction may be the same as the width of the guide slit 33g in the same direction, and is, for example, 1 mm or more and 4 mm or less.

[0090] In this case, as in the first embodiment, the pressure difference between the tip wall 32d side and the inlet 32b side for the refrigerant that has entered the guide region 32i becomes small, and the refrigerant easily flows out from the vicinity of the inlet 32b of the guide slit 33g. At this time, the refrigerant that has entered the guide region 32i easily flows toward the guide plate 33 due to the protrusions 32g. Furthermore, the guide plate 33 is formed with sub-slits 33g1 on both sides of the guide slit 33g and near the protrusions 32g. As a result, the refrigerant that has entered the guide region 32i flows out approximately uniformly from the entire guide slit 33g and the sub-slit 33g1 more reliably than in the first embodiment.

[0091] The sub-slits 33g1 are through which the refrigerant diverted by the protrusions 32g flows out. For this reason, the sub-slits 33g1 are preferably formed from the inlet 31g to at least the protrusions 32g in a plan view with respect to the guide plate 33. The sub-slits 33g1 may extend beyond the protrusions 32g.

[0092] [Fourth embodiment] In the fourth embodiment, a case where a protrusion portion is formed on a bottom plate 30f in the third embodiment will be described with reference to Figs. 23 and 24. Fig. 23 is a cross-sectional view of the cooling device (excluding the guide plate) of the fourth embodiment. Fig. 24 is a plan view of the cooling device of the fourth embodiment. Fig. 23 is a cross-sectional view taken along dashed line YY in Fig. 24.

[0093] In the cooling device 3 of the fourth embodiment, the protrusion 32g is formed on the bottom plate 30f instead of the guide walls 32a, 32c in the cooling device 3 of the third embodiment. In this case, the protrusion 32g is formed between the guide walls 32a, 32c in parallel to the short side walls 31b, 31d in a plan view with respect to the bottom plate 30f. The protrusion 32g may be formed to connect the guide walls 32a, 32c in a plan view.

[0094] The amount of protrusion of the protrusion 32g into the guide area 32i is also within a range that does not impede the flow of the refrigerant, and it is sufficient that the protrusion protrudes even a little. The protrusion 32g may be in a columnar shape, and may be in the shape of a semi-cylindrical, rectangular, or triangular prism.

[0095] Similarly to the second embodiment, the auxiliary slits 33g1 formed in the guide plate 33 are formed on both sides (long side surfaces 33a, 33c sides) of the guide slit 33g within a range sandwiched between the guide walls 32a, 32c in a plan view. The auxiliary slits 33g1 extend from the short side wall 31b toward the short side wall 31d in parallel with the guide slit 33g at least to the protrusion 32g.

[0096] In this case, as in the second embodiment, the pressure difference between the tip wall 32d side and the inlet 32b side for the refrigerant that has entered the guide region 32i becomes small, and the refrigerant easily flows out from the vicinity of the inlet 32b of the guide slit 33g. Furthermore, the guide plate 33 is formed with sub-slits 33g1 on both sides of the guide slit 33g and near the protrusion 32g. As a result, the refrigerant that has entered the guide region 32i flows out approximately uniformly from the entire guide slit 33g and the sub-slit 33g1 more reliably than in the first embodiment.

[0097] The protrusions 32g and the sub-slits 33g1 of the third and fourth embodiments can also be applied to the second embodiment. The protrusions 32g of the third and fourth embodiments may be formed simultaneously. That is, the protrusions 32g are formed at mutually opposing positions of the guide walls 32a and 32c of the guide portion 32, and are further formed on the bottom plate 30f. In this case, the three protrusions 32g may be continuous, and the liquid flows out substantially uniformly from the entire guide slits 33g and the sub-slits 33g1 more reliably than in the third and fourth embodiments.

[0098] [Fifth embodiment] A cooling device 3 of the fifth embodiment will be described with reference to Figs. 25 and 26, in which the guide region 32i of the first embodiment is divided into two. Fig. 25 is a plan view of the cooling device of the fifth embodiment (excluding the guide plate). Fig. 26 is a plan view of the cooling device of the fifth embodiment.

[0099] In the cooling device 3 of the fifth embodiment, in the guide portion 32 of the first embodiment, as shown in Fig. 25, another guide wall 32e is further provided between the guide walls 32a and 32c, thereby forming two guide regions 32i.

[0100] 26, two guide slits 33g penetrating from the front surface 33e to the back surface 33f are formed in the guide plate 33 corresponding to the two guide regions 32i. That is, in a plan view, the guide plate 33 has guide slits 33g formed in an area overlapping the guide region 32i sandwiched between the guide walls 32a and 32e and an area overlapping the guide region 32i sandwiched between the guide walls 32c and 32e.

[0101] In this case as well, when the guide plate 33 is placed on the guide section 32, each guide slit 33g is formed in the guide plate 33 so as to extend in a straight line from the inlet 31g toward the tip wall 32d to just before the tip wall 32d in a plan view. The width (±Y direction) of the guide slit 33g is preferably the same as that of the first embodiment. However, since the space required to form two guide slits 33g is limited, the width may be narrower than that of the first embodiment. Here, it may be, for example, 1 mm.

[0102] The two guide areas 32i in the fifth embodiment also become smaller as they move away from the inlet 31g when viewed in the inflow direction from the inlet 31g of the storage section 31 toward the guide area 32i. Therefore, the pressure difference between the tip wall 32d side and the inlet 32b side becomes smaller for the refrigerant that has entered each of the two guide areas 32i, and the refrigerant easily flows out from each of the two guide slits 33g of the guide plate 33. Therefore, the refrigerant that has flowed into the guide area 32i flows out approximately uniformly from each of the two guide slits 33g. Therefore, the variation in heat dissipation due to the position of the front surface 15e of the heat sink 15 is reduced, the semiconductor unit 2 can be cooled uniformly, the driving cost of the pump can be reduced, and the deterioration of the reliability of the semiconductor device 1 can be suppressed. The protrusions 32g in the third and fourth embodiments may be applied to the guide walls 32a, 32c, and 32e. In this case, the refrigerant that has flowed into the guide area 32i flows out approximately uniformly from each of the two guide slits 33g more reliably.

[0103] Here, the heat dissipation performance when using the cooling device 3 of the third and fifth embodiments and the cooling device 300 of the reference example among the above-mentioned embodiments will be described with reference to Fig. 27 and Fig. 28. Fig. 27 is a graph showing the temperature of the semiconductor chip with respect to the arrangement position of the semiconductor chip. Fig. 28 is a graph showing the pressure loss.

[0104] 27, the horizontal axis indicates the arrangement position of the semiconductor chip 14, and the vertical axis indicates the temperature of the semiconductor chip 14. The arrangement positions of the semiconductor chip 14 are (a) to (f) written in order from the short side surface 15d (outlet 31h) side to the short side surface 15b (inlet 31g) side on the semiconductor chip 14 in FIG. 1. Also, T1 to T5 on the vertical axis of FIG. 27 indicate measured values, which increase from T1 to T5.

[0105] FIG. 28 also shows how much the pressure loss is reduced compared to the reference example (width: 1 mm). The horizontal axis of FIG. 28 represents the measurement target, and the vertical axis represents the pressure loss ([Pa]), which is the pressure difference between the outlet 31h and the inlet 31g. P1 to P8 on the vertical axis of FIG. 28 represent the measured values, which increase from P1 to P8. The reference examples used here are two cases where the width of the guide slit 33g is 1 mm and 2 mm.

[0106] For the semiconductor devices including the cooling devices 300 of the two reference examples and the cooling devices 3 of the third and fifth embodiments, the temperature of the semiconductor chip 14 included in the semiconductor unit 2 after cooling for a predetermined time was measured. In addition, the pressure of the refrigerant at the inlet 31g and the pressure of the refrigerant at the outlet 31h were measured at this time, and the difference was calculated.

[0107] 27, it can be seen that in both reference examples, the temperature of the semiconductor chip 14 on the inlet 31g side is higher than that of the semiconductor chip 14 at other positions. That is, it is considered that the heat dissipation performance is reduced on the inlet 31g side in both reference examples. In addition, when comparing the reference examples, it can be seen that the one with the narrower slit width suppresses the reduction in the heat dissipation performance of the semiconductor chip 14 on the inlet 31g side.

[0108] On the other hand, in the third embodiment, it can be seen that the semiconductor chip 14 is cooled almost uniformly at all positions. In the fifth embodiment, the decrease in heat dissipation is suppressed on the inlet 30g side compared to the reference example (slit width: 2 mm).

[0109] 28, the pressure loss is most suppressed in the case of the third embodiment, which is reduced by about 35% compared to the reference example (slit width: 1 mm). Also, in the case of the fifth embodiment, the pressure loss is reduced by about 20% compared to the reference example (width: 1 mm).

[0110] Therefore, from the results of FIG. 27 and FIG. 28, in the case of the cooling device 3 of the third embodiment, the plurality of semiconductor chips 14 can be uniformly cooled, and the pressure loss can also be sufficiently suppressed.

[0111] Moreover, the cooling device 3 of the fifth embodiment cannot uniformly cool a plurality of semiconductor chips 14 compared to the reference example (width: 2 mm), but the heat dissipation is improved to the same extent as the reference example (width: 1 mm). Also, the pressure loss of the cooling device 3 of the fourth embodiment can be suppressed more than that of the reference example (width: 1 mm). [Explanation of symbols]

[0112] 1 Semiconductor device 2 Semiconductor Unit 3 Cooling device 10, 10a, 10b, 10c Insulated circuit board 11, 11a, 11b, 11c Insulating plate 12, 12a, 12b, 12c Conductive patterns 13,13a,13b,13c Metal plate 14 Semiconductor Chips 14a Control electrode 14b Output electrode 15 Heat sink 15a,15c long side 15b,15d short side 15e Front 15e1 unit area 15f Back 15f1 cooling area 15g fins 16 Joining materials 30 Case 30a,30c long side wall 30b,30d short side wall 30f bottom plate 30g inlet 30h Outlet 30i Storage Area 30j Inflow channel 30k outflow channel 31 Storage section 31a,31c long side wall 31b,31d Short side wall 31g inlet 31h Outlet 31i Storage area 32 Information Department 32a, 32c, 32e Guide wall 32b Inlet 32d End wall 32f bottom 32g protrusion 32i Navigation area 33 Information Board 33a,33c long side 33b,33d short side 33e Front 33f Back 33g Guide slit 33g1 Secondary slit 33h 1st recovery gap 33i 2nd recovery gap

Claims

1. A storage section having a storage area defined by a rectangular bottom surface, a pair of long side surfaces, and a pair of short side surfaces in a plan view, and an inlet is provided on one of the short side surfaces; A guide portion formed on the bottom surface, one end of which is connected to the inside of the one short side surface and the other end of which is connected to the one end of the one short side surface across the inlet, separating a guide area leading to the inlet from the storage area outside the guide area; A flat guide plate is disposed on the guide portion with a gap between each of the pair of long sides in the storage portion, and has a slit extending from one of the short sides to the other short side in an area overlapping the guide area; A semiconductor chip; a heat sink including a front surface having a placement area in which the semiconductor chip is placed, a back surface having a cooling area corresponding to the placement area, and a plurality of fins provided in the cooling area, the back surface being placed on the storage portion, and the plurality of fins being stored in the storage area on the guide plate; having The guide portion is configured such that, when viewed in an inflow direction from the inlet of the storage portion toward the guide area, the guide area of ​​the guide portion becomes smaller as it moves away from the inlet. Semiconductor device.

2. The guide unit is A first guide wall that extends from the one end toward the inflow direction in a plan view, passes through a center of the inlet, and is inclined so as to approach a center line parallel to the pair of long side surfaces; A second guide wall extending from the other end toward the inflow direction and inclined toward the center line; a tip wall connecting end portions of the first guide wall and the second guide wall in the inflow direction; Including, The semiconductor device according to claim 1 .

3. The guide unit is a first guide wall extending in the inflow direction from the one end in a plan view parallel to the pair of long side surfaces; A second guide wall extending from the other end toward the inflow direction in parallel to the pair of long side surfaces; a tip wall connecting end portions of the first guide wall and the second guide wall in the inflow direction; Including, The bottom surface of the guide area is inclined upward toward the guide plate as it moves away from the inlet. The semiconductor device according to claim 1 .

4. The guide unit is A protrusion protruding toward the guide area is provided near the inlet. The semiconductor device according to claim 2 .

5. The protrusions are provided at positions facing the first guide wall and the second guide wall, The semiconductor device according to claim 4.

6. The protrusion is provided on the bottom surface within the guide area. The semiconductor device according to claim 4.

7. The guide plate has a pair of sub-slits formed on both sides of the slit and parallel to the slit, The pair of sub-slits extend from the inlet side to the protrusion in a plan view.

7. The semiconductor device according to claim 5.

8. The width of the pair of auxiliary slits is 1 mm or more and 4 mm or less. The semiconductor device according to claim 7.

9. The guide portion is A first guide wall that extends from the one end toward the inflow direction in a plan view, passes through a center of the inlet, and is inclined so as to approach a center line parallel to the pair of long side surfaces; A second guide wall extending from the other end toward the inflow direction and inclined toward the center line; a third guide wall provided on the center line and extending from the inlet toward the inflow direction; a tip wall connecting end portions of the first guide wall and the second guide wall in the inflow direction; Including, The semiconductor device according to claim 1 .

10. The guide plate, in a plan view, The slits are formed in a region overlapping the guide region sandwiched between the first guide wall and the third guide wall, and in a region overlapping the guide region sandwiched between the third guide wall and the second guide wall, The semiconductor device according to claim 9.

11. An outlet facing the inlet is formed on the other short side surface of the storage section. The semiconductor device according to claim 1 .

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