Cooler and semiconductor module

Abstract

To improve cooling performance of a cooler.SOLUTION: A cooler (1) includes: a top plate portion (100) forming a first surface (102) of a flow path (190) of a refrigerant; a bottom plate portion (121) forming a second surface (123) facing the first surface in the flow path of the refrigerant; a plurality of protrusion portions (110) disposed in the flow path of the refrigerant, and protruding in a direction oriented from the first surface toward the second surface; a frame portion (122) connecting the first surface to the second surface in the flow path of the refrigerant, and forming wall surfaces (124-127) surrounding the plurality of protrusion portions; and a wall portion (140) protruding in a direction oriented from the second surface toward the first surface, and located between a first protrusion portion and a second protrusion portion among the plurality of protrusion portions, the first protrusion portion and the second protrusion portion being spaced apart from each other by a predetermined distance in a flowing direction (X direction) of the refrigerant in the flow path of the refrigerant. The wall portion is connected to each of a pair of the wall surfaces located at ends in a flow path width direction (Y direction) orthogonal to the flowing direction of the refrigerant in plan view of the second surface, and has a section spaced apart from the first surface when viewed in the flow path width direction.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a cooler and a semiconductor module. [Background technology]

[0002] Some coolers for cooling electronic components such as semiconductor devices are provided with a refrigerant flow path through which a refrigerant flows. Some of these types of coolers are provided with a throttle portion that narrows the width of the refrigerant flow path, thereby improving the cooling efficiency downstream of the throttle portion (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-182313 Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-described cooler, the cooling efficiency at the downstream of the coolant flow path decreases due to an increase in the temperature of the coolant flowing in the portion of the coolant flow path that is close to the surface on which the electronic components are arranged.

[0005] The present invention has been made in view of the above points, and an object of the present invention is to improve the cooling performance of a cooler. [Means for solving the problem]

[0006] A cooler according to one aspect of the present invention includes a top plate forming a first surface of a refrigerant flow path, a bottom plate forming a second surface of the refrigerant flow path opposite the first surface, a plurality of protrusions disposed within the refrigerant flow path and protruding from the first surface toward the second surface, a frame connecting the first surface and the second surface of the refrigerant flow path to form a wall surface surrounding the plurality of protrusions, and a wall portion protruding from the second surface toward the first surface between a first protrusion and a second protrusion of the plurality of protrusions that are spaced a predetermined distance apart in the flow direction of the refrigerant in the refrigerant flow path. The wall portion is connected to each of a pair of wall surfaces located at ends of a flow path width direction perpendicular to the flow direction of the refrigerant in a plan view of the second surface, and has a section spaced from the first surface when viewed in the flow path width direction. [Effects of the Invention]

[0007] According to the present invention, the cooling performance of the cooler can be improved. [Brief explanation of the drawings]

[0008] [Figure 1] 1A and 1B are perspective views illustrating an example of the external configuration of a cooler according to a first embodiment. [Figure 2] FIG. 2 is a plan view of the cooler with a portion thereof omitted. [Figure 3] FIG. 3 is a side cross-sectional view of the cooler taken along line AA' in FIG. 2. [Figure 4] FIG. 3 is a side cross-sectional view of the cooler taken along line BB′ in FIG. 2. [Figure 5] FIG. 10 is a diagram supplementing the shape of the wall of the cooler. [Figure 6] FIG. 4 is a partial cross-sectional view illustrating the flow of refrigerant around a wall portion. [Figure 7] FIG. 10 is a partial plan view illustrating the flow of refrigerant around a wall portion. [Figure 8] 10 is a graph illustrating the relationship between the height of a wall portion and cooling performance. [Figure 9]10 is a graph illustrating the relationship between the depth of the cutout section and the cooling performance. [Figure 10] 10 is a partial plan view illustrating an example of the shape of a wall portion in a cooler according to a second embodiment. FIG. [Figure 11] 10 is a graph illustrating the relationship between the length of the cutout section of the wall portion and the cooling performance. [Figure 12] 10A and 10B are perspective views illustrating modified shapes of cutout sections provided in the wall portion. [Figure 13] 13A and 13B are partial cross-sectional views illustrating modifications of the height of the wall portion. [Figure 14] 10 is a partial plan view illustrating a modified example of the shape of the upstream wall surface of the wall portion. FIG. [Figure 15] 10A and 10B are partial side cross-sectional views illustrating a modified example of a method for providing a wall portion. [Figure 16] 16A and 16B are side cross-sectional views illustrating modified examples of the cooler configuration. [Figure 17] 1 is a plan view showing a configuration example of a semiconductor module to which a cooler according to an embodiment is attached; [Figure 18] 1 is an equivalent circuit diagram of an exemplary power conversion circuit formed in a semiconductor module. [Figure 19] FIG. 10 is a plan view illustrating an example of the arrangement of the wall portion of the cooler. DETAILED DESCRIPTION OF THE INVENTION

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

[0010] In this specification, the Z direction is sometimes referred to as the up-down direction. In this specification, "up" and "above" refer to the positive side of the Z direction relative to a reference surface, component, position, etc., and "down" and "below" refer to the negative side of the Z direction relative to a reference surface, component, position, etc. For example, when describing "component B being placed on component A," component B is placed on the positive side of component A in the Z direction. Furthermore, when describing "the top surface of component A," this surface is the end of component A on the positive side of the Z direction, facing the positive side of the Z direction. These directions and surfaces are used for convenience of explanation, and their correspondence with the X-axis, Y-axis, and Z-axis directions may change depending on the installation orientation of the cooler, etc. For example, the surface of a cooler on which a wiring board and semiconductor elements are placed is referred to as the top surface of the cooler in this specification, but may also be referred to as the bottom surface, side surface, etc. of the cooler. In this specification, the X-direction, Y-direction, and Z-direction may be expressed as directions associated with the refrigerant flow path.

[0011] The aspect ratios and relative sizes of the components in each figure are merely schematic representations and do not necessarily correspond to the relationships in an actual cooler or the like that will be manufactured. For the sake of convenience, it is assumed that the relative sizes of the components may be exaggerated. In addition, some of the reference numerals in each figure are underlined to indicate that they refer to the entire component when a part of the component referenced by that reference numeral is referenced by another reference numeral.

[0012] In the following description, detailed descriptions of the configuration, function, operation, manufacturing method, etc. of the illustrated cooler that are the same as or similar to those of known coolers will be omitted.

[0013] [First embodiment] 1A and 1B are perspective views illustrating an example of the external configuration of a cooler according to a first embodiment. FIG. 2 is a plan view in which a portion of the cooler is omitted. FIG. 3 is a side cross-sectional view of the cooler taken along line A-A' in FIG. 2. FIG. 4 is a side cross-sectional view of the cooler taken along line B-B' in FIG. 2. FIG. 5 is a diagram supplementing the shape of a wall portion of the cooler. The side cross-sectional view of FIG. 3 is a view of the cooler taken along line A-A' in FIG. 2, showing a portion above line A-A' as viewed from the negative side in the Y direction. The side cross-sectional view of FIG. 4 is a view of the cooler taken along line B-B' in FIG. 2, showing a portion to the left of line B-B' as viewed from the negative side in the X direction. FIG. 5 illustrates a portion of the cooler in the YZ plane on the negative side in the X direction of line B-B' in FIG. 2, and hatching indicating a cross section is omitted.

[0014] 1A, 1B, and 2 to 4 includes a top plate 100 and a water jacket 120. The top plate 100 and the water jacket 120 are made of a metal or alloy with high thermal conductivity, such as aluminum or copper, and are manufactured by a well-known method, such as casting, press processing, or a method using a 3D printer.

[0015] The top plate 100 has heating elements 2A and 2B arranged on an upper surface 101 and a plurality of protrusions (pin fins) 110 arranged on a lower surface 102. The illustrated top plate 100 is a rectangular plate-shaped member when viewed from above on the upper surface 101, and has two heating elements 2A and 2B arranged in the longitudinal direction (X direction). The heating elements 2A and 2B may be, for example, semiconductor elements 201 arranged on the upper surface of a wiring board 202. As illustrated in FIG. 1B, a plurality of protrusions 110 are arranged on the lower surface 102 of the top plate 100 in each of the regions where the heating elements 2A and 2B are arranged in a plan view of the lower surface 102. The protrusions 110 arranged in the first region where the first heating element 2A is arranged and the protrusions 110 arranged in the second region where the second heating element 2B is arranged are spaced apart by a predetermined distance that is longer than the distance between the protrusions 110 in the same region. The shape of the protrusions 110 is not limited to the cylindrical shape shown in the figure. The arrangement pattern of the protrusions 110 is not limited to a specific pattern. The top plate 100 is an example of a top plate portion that forms a first surface in a flow path 190 for the coolant.

[0016] The water jacket 120 is a component attached to the underside 102 of the top plate 100 to form a refrigerant flow path 190, and includes a bottom plate portion 121 and a frame portion 122. The bottom plate portion 121 is a flat portion that forms a bottom surface 123 that faces the underside 102 of the top plate 100 in the refrigerant flow path 190, and whose longitudinal direction is the X direction in a plan view of the bottom surface 123. The frame portion 122 is a portion that is in the shape of a quadrangular ring in a plan view of the bottom surface 123, and that connects the bottom surface 123 and the underside 102 of the top plate 100 in the refrigerant flow path 190 and forms wall surfaces 124 to 127 that surround the protrusion 110 of the top plate 100. The bottom plate portion 121 is an example of a bottom plate portion that forms a second surface that faces the first surface (the lower surface 102 of the top plate 100) of the refrigerant flow path 190, and the frame portion 122 is an example of a frame portion that forms a wall surface that connects to the first and second surfaces of the refrigerant flow path 190 and surrounds the multiple protrusions 110. A groove for arranging a packing 180 is formed on the upper surface of the frame portion 122. Furthermore, the illustrated water jacket 120 has through holes 130 and 131 that communicate the refrigerant flow path 190 with the outside space formed at both ends of the bottom plate portion 121 in the longitudinal direction. The refrigerant that flows into the refrigerant flow path 190 from one of the through holes (for example, the through hole 130 on the negative side in the X direction) flows in the longitudinal direction (X direction) and flows out from the other through hole (for example, the through hole 131 on the positive side in the X direction). In the cooler 1 of this embodiment, heat generated by the heating elements 2A and 2B arranged on the upper surface 101 of the top plate 100 is conducted to the protrusion 110 of the top plate 100, and heat exchange occurs between the protrusion 110 and the refrigerant flowing through the refrigerant flow path 190, thereby cooling the heating elements 2A and 2B.

[0017] Furthermore, the water jacket 120 of the cooler 1 of the present embodiment has a wall portion 140 protruding from the bottom surface 123. Both ends of the wall portion 140 in the flow path width direction (Y direction) orthogonal to the refrigerant flow direction (X direction) in the plan view of the bottom surface 123 are respectively connected to the wall surfaces 124 and 126 of the frame portion 122. The upper surface of the wall portion 140 is spaced apart from the lower surface 102 of the top plate 100, and when viewed along the flow path width direction, it has a section 141 with a height H0 and a notch section 142 whose height from the bottom surface 123 varies within a range from H0 to H1 (<H0). The illustrated notch section 142 of the wall portion 140 is provided in a V shape that is substantially coincident with the positions of both ends of the semiconductor element 201, which is the heat source of the heating elements 2A and 2B, at both ends in the flow path width direction (see FIG. 4), and is the lowest at an intermediate position equidistant from both ends. The water jacket 120 having the wall portion 140 provided with such a notch section 142 can suppress variations in the shape of the notch section 142 when formed by, for example, aluminum casting.

[0018] As illustrated in FIG. 5, in the cooler 1, the relationship between the height H0 of the wall portion 140 and the height (dimension in the Z direction) Pz of the refrigerant flow path 190 is Pz > H0, and the difference Pz - H0 is associated with the cooling performance, which will be described later with reference to FIG. 8. Also, the relationship between the lowest height H1 of the notch section 142 and the distance G1 from the bottom surface 123 to the lower surface of the protrusion 110 is H1 > G1, and the distance G1 is set based on, for example, the manufacturing tolerance of the cooler 1. The lowest height H1 of the notch section 142 can be a value obtained by subtracting the maximum depth H2 of the notch in the notch section 142 from the height H0 (that is, H1 = H0 - H2). The distance G2 between the wall surface 124 at the end in the flow path width direction (Y direction) of the frame portion 122 and the protrusion 110 closest to the wall surface 124 is also set based on the manufacturing tolerance of the cooler 1.

[0019] 3 may be, for example, within a range of 4 mm to 10 mm, but is not limited to a specific value. A distance G3 between the wall 140 and the protrusion 110 closest to the wall 140 on the upstream side of the wall 140, and a distance G4 between the wall 140 and the protrusion 110 closest to the wall 140 on the downstream side of the wall 140, are set based on the manufacturing tolerance of the cooler 1, and are not limited to a specific value.

[0020] Fig. 6 is a partial cross-sectional view illustrating the flow of the refrigerant around the wall portion. Fig. 7 is a partial plan view illustrating the flow of the refrigerant around the wall portion. In Fig. 6 and Fig. 7, the flow of the refrigerant is schematically indicated by solid arrows and dotted arrows.

[0021] In the cooler 1 of the present embodiment, the refrigerant flowing through the refrigerant flow path 190 exchanges heat with the protrusions 110 while repeatedly branching and merging at the protrusions 110, as illustrated in Fig. 7, so the temperature of the refrigerant flowing between the protrusions 110 increases downstream. Furthermore, as illustrated in Fig. 6, if a clearance is provided between the bottom surface 123 of the refrigerant flow path 190 and the lower surface of the protrusions 110, the temperature rise of the refrigerant caused by heat exchange between the refrigerant flowing along the bottom surface 123 and the protrusions 110 is suppressed. Similarly, if a clearance is provided between the wall surfaces 124, 126 of the refrigerant flow path 190 and the protrusions 110, the temperature rise of the refrigerant caused by heat exchange between the refrigerant flowing along the wall surfaces 124, 126 and the protrusions 110 is suppressed. However, in conventional coolers 1 that do not have wall portion 140, the refrigerant flowing along bottom surface 123 and wall surfaces 124, 126 and the refrigerant flowing between protrusions 110 are not mixed, and the relatively low-temperature refrigerant flowing along bottom surface 123 and wall surfaces 124, 126 cannot be effectively used to cool downstream heat-generating element 2B.

[0022] On the other hand, in the cooler 1 of the present embodiment, as illustrated in FIG. 6 , the refrigerant flowing along the bottom surface 123 collides with the wall portion 140, causing a flow of the refrigerant along the wall portion 140 toward the underside 102 of the top plate 100. This promotes mixing of the relatively high-temperature refrigerant flowing in the portion of the top plate 100 close to the underside 102 (between the protrusions 110) and the relatively low-temperature refrigerant flowing along the bottom surface 123. Furthermore, as illustrated in FIG. 7 , the refrigerant flowing along the wall surfaces 124 and 126 collides with the wall portion 140, causing a flow of the refrigerant along the wall surface 140 toward the cutout section 142. This promotes mixing of the relatively high-temperature refrigerant flowing between the protrusions 110 (particularly between the protrusions 110 in the active region overlapping with the semiconductor element 201 in a plan view) and the relatively low-temperature refrigerant flowing along the wall surfaces 124 and 126. Therefore, in the cooler 1 of the present embodiment, the temperature of the refrigerant flowing between the protrusions 110 downstream of the wall portion 140 can be lowered compared to when the wall portion 140 is not present. Furthermore, when a clearance is provided between the bottom surface 123 and the lower surface of the protrusion 110, the flow velocity of the refrigerant flowing along the bottom surface 123 is higher than the flow velocity of the refrigerant flowing between the protrusions 110. Similarly, when a clearance is provided between the wall surfaces 124, 126 and the protrusion 110, the flow velocity of the refrigerant flowing along the wall surfaces 124, 126 is higher than the flow velocity of the refrigerant flowing between the protrusions 110. The refrigerant flowing at a higher flow velocity than the refrigerant flowing between the protrusions 110 collides with the wall portion 140 and flows into the cutout section 142, thereby increasing the flow velocity of the refrigerant passing through the cutout section 142. Therefore, heat exchange occurs between the refrigerant whose temperature rise is suppressed and whose flow velocity is increased due to stirring downstream of the wall portion 140 and the protrusion 110, improving the cooling performance of the cooler.

[0023] In particular, wall portion 140 in cooler 1 of the present embodiment, unlike the throttling portion in the cooler of Patent Document 1, can promote mixing of a relatively low-temperature refrigerant flowing along bottom surface 123 in refrigerant flow path 190 and a relatively high-temperature refrigerant flowing along underside 102 of top plate 100. Therefore, cooler 1 of the present embodiment has improved cooling performance compared to the cooler of Patent Document 1.

[0024] Fig. 8 is a graph illustrating the relationship between the height of the wall portion and cooling performance. Fig. 9 is a graph illustrating the relationship between the depth of the cutout section and cooling performance. In the graph of Fig. 8, the thermal resistance value on the left vertical axis and the pressure loss on the right vertical axis may be relative values ​​to the thermal resistance value and pressure loss when H0 / 5.5=0 on the horizontal axis. In the graph of Fig. 9, the thermal resistance value on the left vertical axis and the pressure loss on the right vertical axis may be relative values ​​to the thermal resistance value and pressure loss in a cooler that does not have the above-mentioned wall portion 140, respectively.

[0025] The graph in FIG. 8 shows the relationship between the ratio H0 / 5.5 of the height H0 of the wall portion 140 to the height Pz of the refrigerant flow path 190 when the height Pz is 5.5 mm, and the thermal resistance and pressure loss. In this example, as illustrated in FIG. 5 and other figures, the positions of both ends of the cutout sections 142 and 143 of the wall portion 140 in the flow path width direction (Y direction) are aligned with the positions of both ends of the semiconductor element 201 in the width direction, and the maximum depth H2 of the cutout is constant. The thermal resistance and pressure loss when H0 / 5.5=0 in the graph in FIG. 8 correspond to the thermal resistance and pressure loss in a cooler without the wall portion 140. As shown in the graph in FIG. 8, the thermal resistance decreases as the height H0 of the wall portion 140 increases, but the pressure loss increases when the height ratio H0 / 5.5 is greater than 0.9. In other words, when the height ratio H0 / 5.5 is greater than 0.9, the flow rate of the refrigerant decreases, resulting in a decrease in cooling performance. For this reason, it is preferable that the height H0 of the wall portion 140 is set so that the ratio H0 / Pz of the height H0 of the wall portion 140 to the height Pz of the refrigerant flow path 190 is in the range of 0.2≦H0 / Pz≦0.9. In other words, it is preferable that the height H0 of the wall portion 140 is set to 20% to 90% of the height Pz of the refrigerant flow path 190.

[0026] The graph in Figure 9 shows the relationship between the ratio H1 / 4 of the minimum height H1 of the cutout section to the height H0 of the wall section 140 when the height H0 is 4 mm, and the thermal resistance and pressure loss. In this example, the height Pz of the refrigerant flow path 190 is 5.5 mm, and the positions of both ends of the cutout section 142 of the wall section 140 in the flow path width direction (Y direction) are aligned with the positions of both ends of the semiconductor element 201 in the flow path width direction. The thermal resistance and pressure loss for "no wall" in the graph in Figure 9 are the thermal resistance and pressure loss for a cooler without the wall section 140. As shown in the graph in Figure 9, the thermal resistance is a substantially constant value lower than that in the case without the wall, regardless of the minimum height H1 of the cutout section. However, as the height ratio H1 / 4 approaches 0, the flow path area of ​​the cutout section 142 increases, and the pressure loss decreases. However, the difference in pressure loss compared to when wall portion 140 is not provided is approximately the same as the difference in pressure loss between when H0 / 5.5=0 and when 0.2≦H0 / 5.5≦0.9 in the graph of Fig. 8. Therefore, the minimum height H1 of the cutout section of wall portion 140 can be set so that the ratio H1 / H4 of the minimum height H1 to the height H0 of wall portion 140 is within the range of 0≦H1 / H0≦1. Note that in the case of wall portion 140 where H1 / H0=1, i.e., wall portion 140 without a cutout section, it is preferable to determine the ratio H0 / Pz of the height H0 of wall portion 140 to the height Pz of refrigerant flow path 190 so that the increase in pressure loss falls within an allowable range, as described above with reference to Fig. 8.

[0027] The number and shape of the cutout sections 142 in the wall section 140 of the cooler 1 of this embodiment can be changed as appropriate depending on the heat generating element 2 to be placed on the upper surface 101 of the top plate 100. For example, when there is one semiconductor element 201 in the heat generating element 2 downstream of the wall section 140, or when two or more semiconductor elements 201 are arranged in the refrigerant flow direction (X direction), the wall section 140 may have one cutout section 142 (see FIG. 19 ). Also, when three or more semiconductor elements 201 are arranged in the flow path width direction (Y direction) of the heat generating element 2 to be placed downstream of the wall section 140, the wall section 140 may have the same number of cutout sections 142 as the number of semiconductor elements 201. Furthermore, the dimension of one cutout section 142 in the flow path width direction does not have to match the dimension of the semiconductor element 201 in the flow path width direction. The shape of the cutout section 142 is not limited to a V-shape when viewed from the upstream side as illustrated in FIGS. 4 and 5, but may be other shapes such as a rectangle or a U-shape.

[0028] [Second embodiment] Fig. 10 is a partial plan view illustrating the shape of the wall portion in the cooler according to the second embodiment. Fig. 11 is a graph illustrating the relationship between the length of the cutout section of the wall portion and cooling performance. In the graph of Fig. 11, the thermal resistance value on the left vertical axis and the pressure loss on the right vertical axis may be relative values ​​to the thermal resistance value and pressure loss, respectively, in a cooler that does not have the above-mentioned wall portion 140.

[0029] In the cooler 1 of the present embodiment, as illustrated in FIG. 10, the wall portion 140 has a section 145 where the thickness of the wall portion 140 (dimension in the refrigerant flow direction (X direction)), represented by the distance from the wall surface 144 facing the downstream side, is W0, and a notch section 146 that varies within the range from W0 to W1 (<W0). Similar to the notch section 142 described in the first embodiment, the notch section 146 can be a section having substantially the same positions as both ends of the semiconductor element 201 in the flow path width direction at both ends. The wall portion 140 illustrated in FIG. 10 has a constant height when viewed in the flow path width direction (Y direction) and is spaced apart from the lower surface 102 of the top plate 100. Even when such a wall portion 140 is provided, stirring of the relatively low-temperature refrigerant flowing along the bottom surface 123 and colliding with the wall portion 140 and the relatively high-temperature refrigerant flowing along the lower surface 102 of the top plate 100, and stirring of the relatively low-temperature refrigerant flowing along the wall surfaces 124 and 126 and colliding with the wall portion 140 and the relatively high-temperature refrigerant flowing between the wall portion 140 and the protrusion 110 are promoted. For this reason, the temperature of the refrigerant flowing downstream of the wall portion 140 is made uniform, and the cooling performance is improved.

[0030] The graph in Figure 11 shows the relationship between the ratio W1 / 4 of the minimum width W1 of the cutout section to the width W0 of the wall section 140 when the width W0 is 4 mm, and the thermal resistance and pressure loss. In this example, the height Pz of the refrigerant flow path 190 is 5.5 mm, the height H0 of the wall section 140 is 4 mm, and the positions of both ends of the cutout section 146 of the wall section 140 in the flow path width direction (Y direction) are aligned with the positions of both ends of the semiconductor element 201 in the flow path width direction. The thermal resistance and pressure loss for "without wall" in the graph in Figure 11 are the thermal resistance and pressure loss in a cooler without the wall section 140. As shown in the graph in Figure 11, the thermal resistance remains approximately constant and smaller than the case without the wall, regardless of the minimum width W1 of the cutout section 146, but the pressure loss is larger than the case without the wall. Furthermore, when the height is constant as in the case of the wall portion 140 of this embodiment, stagnation is likely to occur upstream of the wall portion 140 when the width ratio W1 / 4 is small or large. In other words, the amount of refrigerant flowing from the upstream side to the downstream side through the gap between the undersurface 102 of the top plate 100 and the wall portion 140 decreases. However, the difference in pressure loss compared to when the wall portion 140 is not provided is approximately the same as the difference in pressure loss when H0 / 5.5=0 and when 0.2≦H0 / 5.5≦0.9 in the graph of FIG. 8 . For this reason, it is preferable that the minimum width W1 of the cutout section 146 of the wall portion 140 in the cooler 1 of this embodiment be such that the ratio W1 / W0 of the minimum width W1 to the width W0 of the wall portion 140 is within the range of 0.25≦W1 / W0≦1. In other words, it is preferable that the minimum width W1 when the cutout section 146 of the wall portion 140 is provided be 25% or more of the width W0 of the wall portion 140. Furthermore, in the case of a wall portion 140 where W1 / W0=1, i.e., a wall portion 140 where no cutout section 146 exists, as described above, it is preferable to determine the ratio H0 / Pz of the height H0 of the wall portion 140 to the height Pz of the refrigerant flow path 190 so that the increase in pressure loss falls within an acceptable range.

[0031] The number and shape of the notched sections 146 provided in the wall section 140 of the cooler 1 of this embodiment can be changed as appropriate depending on the heat generating element 2 to be placed on the upper surface 101 of the top plate 100.

[0032] [Variations] Fig. 12 is a perspective view illustrating a modified example of the shape of a cutout section provided in a wall section. The cutout section of a wall section 140 provided in the cooler 1 may have a shape that includes both a variation in height from the bottom surface 123 described in the first embodiment and a variation in thickness represented by the distance from the downstream wall surface 144 described in the second embodiment, like cutout section 148 illustrated in Fig. 12. The wall section 140 illustrated in Fig. 12 has a flow path area of ​​cutout section 148 as viewed from the upstream side that is wider than that of the wall section 140 with a constant height described in the second embodiment, and therefore can suppress an increase in pressure loss.

[0033] 13A and 13B are partial cross-sectional views illustrating modified examples of the height of the wall portion. FIG. 13A shows an example of a wall portion 140 in which two sections connected to a cutout section 142 have different heights. In the wall portion 140 shown in FIG. 13A, a height H4 of a section 141A located on the positive side of the cutout section 142 in the Y direction (i.e., located between the wall surface 124 of the water jacket 120 and the cutout section 142) and a height H5 of a section 141B located on the negative side of the cutout section 142 in the Y direction satisfy the relationship H4>H5. A cooler 1 having such a wall portion 140 can prevent refrigerant that flows along the wall surface 124 and collides with the wall portion 140 from flowing downstream through the gap between the wall portion 140 and the top plate 100. This allows for more effective mixing of the relatively high-temperature refrigerant that flows between the protrusions 110 toward the cutout section 142 and the relatively low-temperature refrigerant that flows along the wall surface 124. Furthermore, by reducing height H5 of section 141B of wall portion 140 away from the end of the wall portion 140 in the flow path width direction (Y direction), it is possible to suppress a decrease in flow path area and an increase in pressure loss. Note that, for example, as shown in FIG. 13B, wall portion 140 may vary in height from H4 to H5 within section 141A located between wall surface 124 of water jacket 120 and notched section 142. In this case, by setting only the portion close to wall surface 124 to height H4 (>H5) based on clearance CL2 between wall surface 124 and protrusion 110, it is possible to further reduce the amount of refrigerant that flows downstream along wall surface 124, passing between wall portion 140 and top plate 100, and further suppress a decrease in flow path area and an increase in pressure loss.

[0034] FIG. 14 is a partial plan view illustrating a modified example of the shape of the upstream wall surface of the wall portion. As illustrated in FIG. 14 , the upstream wall surface 149 of the wall portion 140 may have a shape in which the end portion in the flow path width direction of the bottom surface 123 in a plan view is displaced upstream as it approaches the wall surface 124 of the frame portion 122 of the water jacket 120. This shape facilitates guiding the refrigerant that flows along the wall surface 124 and collides with the wall portion 140 toward the cutout section 142. This prevents refrigerant from accumulating at the corner where the wall surface 124 of the frame portion 122 and the upstream wall surface 149 of the wall portion 140 connect, thereby preventing an increase in pressure loss and a decrease in cooling performance. The connecting portion of the wall surface 149 with the wall surface 124 of the frame portion 122 is not limited to a curved surface shape represented by a curve as illustrated in FIG. 14 , but may also have a planar shape represented by a straight line (tapered shape).

[0035] 15 is a partial side cross-sectional view illustrating a modified method of providing the wall portion. The wall portion 140 of the cooler 1 described above is integrally formed with the bottom plate portion 121 as part of the water jacket 120. However, the wall portion 140 may be formed (manufactured) separately from the bottom plate portion 121 of the water jacket 120 and joined to the bottom surface 123 of the bottom plate portion 121, the wall surface 124 of the frame portion 122, etc. by a well-known joining material 160.

[0036] 16A and 16B are side cross-sectional views illustrating modified examples of the cooler configuration. The cooler 1 described above has a water jacket 120, in which a bottom plate portion 121 and a frame portion 122 are integrally formed, attached to a top plate 100 to form a refrigerant flow path 190. However, as illustrated in FIG. 16A, the cooler 1 may have a frame portion 122 integrally formed on the underside 102 of the top plate 100, and the underside of the frame portion 122 covered by the bottom plate portion 121 to form the refrigerant flow path 190. Furthermore, as illustrated in FIG. 16B, the cooler 1 may have a top plate 100, a bottom plate portion 121, and a frame portion 122 that are separate bodies, and the frame portion 122 is disposed between the top plate 100 and the bottom plate portion 121 and integrated to form the refrigerant flow path 190. Although detailed description with reference to the drawings will be omitted, the inlet and outlet of the refrigerant in the cooler 1 are not limited to being formed in the bottom plate portion 121, but may be formed in the frame portion 122 or in the top plate 100. Furthermore, the lower surfaces of the multiple protrusions (pin fins) 110 may be connected to the bottom surface 123 of the bottom plate portion 121 directly or via a member such as a bonding material.

[0037] The above-described cooler 1 is not applied to cooling specific heat generating bodies 2A, 2B, but is particularly suitable for cooling semiconductor elements of a semiconductor module used in a power conversion device such as an inverter device. The semiconductor module may be a semiconductor module having a long dimension in the flow direction (X direction) of a refrigerant flow path 190 as described below with reference to Figures 17 to 19, but is not limited to one with a specific configuration.

[0038] [Application example to semiconductor modules] Fig. 17 is a plan view showing a configuration example of a semiconductor module equipped with a cooler according to an embodiment. Fig. 18 is an equivalent circuit diagram of an exemplary power conversion circuit formed in the semiconductor module. Fig. 19 is a plan view illustrating an example of the arrangement of the wall portion of the cooler.

[0039] The semiconductor module 3 illustrated in FIG. 17 includes three heat generating elements 2A, 2B, and 2C arranged in the longitudinal direction on the upper surface 101 of the top plate 100 of the cooler 1. Each of the heat generating elements 2A, 2B, and 2C includes a wiring board 200 and two semiconductor elements 201 arranged on the upper surface of the wiring board 200 (see FIG. 19). The wiring board 200 has conductor patterns arranged on the upper and lower surfaces of an insulating substrate, and the conductor pattern arranged on the lower surface of the insulating substrate is connected to the top plate 100 of the cooler 1 so as to be in close contact with the insulating substrate by a bonding material such as solder or a thermally conductive material such as thermal grease or thermal compound. The conductor pattern arranged on the upper surface of the insulating substrate is electrically connected to the electrodes of the semiconductor elements 201 or to terminals of a case 300 attached to the upper surface 101 of the top plate 100. The wiring board 200 may be, for example, a direct copper bonding (DCB) substrate or an active metal brazing (AMB) substrate. The insulating substrate may be a ceramic substrate formed from a ceramic material such as aluminum oxide (Al2O3), aluminum nitride (AlN), silicon nitride (Si3N4), or a composite material of aluminum oxide (Al2O3) and zirconium oxide (ZrO2). The insulating substrate may be, for example, a substrate formed from an insulating resin such as epoxy resin, a substrate formed by impregnating a base material such as glass fiber with an insulating resin, or a substrate formed by coating the surface of a flat metal core with an insulating resin. The conductor pattern may be, for example, a metal foil such as copper or aluminum. The wiring board 200 may be called a laminated substrate, an insulating circuit board, or the like. The conductor pattern may be called a conductor layer, a conductive layer, or the like.

[0040] 17 has three power conversion circuits formed therein, as shown in Fig. 18. The power conversion circuits are formed by wiring board 200 of one heating element and semiconductor element 201, and include switching elements 330 and 331, such as IGBT (Insulated Gate Bipolar Transistor) elements, connected in series between P-terminal 301 and N-terminal 302 provided in case 300, and diode elements 332 and 333, such as FWD (Free Wheeling Diode) elements, connected in anti-parallel to the IGBT elements. The emitter of switching element 330 of the upper arm, whose collector is connected to P-terminal 301, and the collector of switching element 331 of the lower arm, whose collector is connected to N-terminal 302, are connected to M-terminal 303 provided in case 300. The gate of the upper arm switching element 330 is connected to a first control terminal 304 provided on the case 300, and the gate of the lower arm switching element 331 is connected to a second control terminal 305 provided on the case 300. The diode element connected in anti-parallel to the switching element may be formed in a semiconductor element different from the semiconductor element in which the switching element is formed, or may be formed within the semiconductor element in which the switching element is formed. That is, the switching element and the diode element may be formed in a single semiconductor element 201. The semiconductor substrate on which the switching element and the diode element in the semiconductor element are formed is not limited to a silicon substrate, and may be, for example, a wide bandgap semiconductor substrate such as a SiC (silicon carbide) substrate or a GaN (gallium nitride) substrate. The electronic circuit formed in the semiconductor module 3 is not limited to the power conversion circuit exemplified in FIG. 17.

[0041] The cooler applicable to the semiconductor module 3 illustrated in FIG. 17 includes a cooler in which the refrigerant flows in the transverse direction (Y direction) and a cooler in which the refrigerant flows in the longitudinal direction (X direction). In a cooler in which the refrigerant flows in the transverse direction, in order to uniformly cool the three heat generating elements 2A, 2B, and 2C arranged in the longitudinal direction, a header section must be provided upstream of the area overlapping with the heat generating elements in a plan view to distribute the refrigerant that flows from the inlet into the refrigerant flow path in the longitudinal direction. For this reason, when the refrigerant flows in the transverse direction, it is difficult to reduce the dimensions of the cooler in the transverse direction. In contrast, in a cooler 1 in which the refrigerant flows in the longitudinal direction, the refrigerant that flows from the inlet into the refrigerant flow path can be distributed in the transverse direction without providing a header section, as illustrated in FIG. 19, which makes it easier to reduce the planar dimensions of the cooler 1.

[0042] Furthermore, when the above-described wall portion 140 is provided in the refrigerant flow path of the cooler 1 whose longitudinal direction is the refrigerant flow direction, for example, by providing the wall portion 140 between each of the arrangement areas of adjacent heat generating elements in a plan view, as shown in Fig. 19, the cooling performance for the downstream heat generating element 2C can be made closer to the cooling performance for the upstream heat generating element 2A. Since the heat generating elements 2A, 2B, and 2C illustrated in Fig. 19 have two semiconductor elements 201 lined up in the longitudinal direction, one notched section 142 is provided in the wall portion 140.

[0043] The semiconductor module 3 to which the cooler 1 according to the above-described embodiment is attached is not limited to one having a case 300 as exemplified in Fig. 17. The semiconductor module 3 may be, for example, a DIP (Dual Inline Package) type semiconductor module, which is sometimes called a semiconductor package.

[0044] The embodiments of the cooler and semiconductor module according to the present invention are not limited to the above-described embodiments, and may be variously changed, substituted, or modified without departing from the spirit of the technical idea. Furthermore, if the technical idea can be realized in a different way due to technological advances or other derived technologies, it may be implemented using that method. Therefore, the claims cover all embodiments that may fall within the scope of the technical idea.

[0045] The semiconductor modules of the above-described embodiments may be applied to industrial power conversion devices, such as inverter devices that drive motors in elevators, escalators, building air conditioning systems, etc. The use of the semiconductor module is not limited to a specific application. For example, the semiconductor module may also be applied to power conversion devices such as inverter devices that drive motors in vehicles such as four-wheeled automobiles and motorcycles, and railroad cars. The semiconductor modules of the above-described embodiments are not limited to inverter devices, and may also provide other functions.

[0046] The features of the above-described embodiment will be summarized below. The cooler according to the above-described embodiment includes a top plate portion forming a first surface in a refrigerant flow path, a bottom plate portion forming a second surface opposite to the first surface in the refrigerant flow path, a plurality of protrusions disposed within the refrigerant flow path and protruding from the first surface toward the second surface, a frame portion connecting the first surface and the second surface in the refrigerant flow path and forming a wall surface surrounding the plurality of protrusions, and a wall portion protruding from the second surface toward the first surface between a first protrusion and a second protrusion among the plurality of protrusions that are spaced a predetermined distance apart in the flow direction of the refrigerant in the refrigerant flow path, and the wall portion is connected to each of a pair of wall surfaces located at the ends of the flow path width direction perpendicular to the flow direction of the refrigerant in a plan view of the second surface, and has a section spaced apart from the first surface when viewed in the flow path width direction.

[0047] In the cooler according to the above embodiment, the wall portion is provided in an area in the refrigerant flow path between a first area in which a plurality of protrusions including the first protrusion are arranged and a second area in which a plurality of protrusions including the second protrusion are arranged, where the protrusions are not arranged.

[0048] In the cooler according to the above embodiment, the plurality of protrusions are spaced apart from the second surface.

[0049] In the cooler according to the above embodiment, the wall portion has a varying height from the second surface as viewed in the flow path width direction.

[0050] In the cooler according to the above embodiment, the height of the wall portion from the second surface is within the range of 20% to 90% of the height of the refrigerant flow path from the second surface to the first surface at the position of the wall portion.

[0051] In the cooler according to the above embodiment, the wall portion varies so that the height of a section sandwiched at substantially the same position as both ends of the flow path width direction of the heat generating element arranged on the third surface, which is the reverse side of the first surface of the top plate portion, when viewed in plan, is lower than the height of the section adjacent to that section.

[0052] In the cooler according to the above embodiment, the height of the section having both ends substantially at the same positions as both ends of the heat generating element in the flow channel width direction varies in a V-shape along the flow channel width direction.

[0053] In the cooler according to the above embodiment, the thickness of the wall portion from the downstream wall surface to the upstream wall surface of a section whose ends are substantially the same as the ends of the flow path width direction of the heating element arranged on the third surface, which is the backside of the first surface of the top plate portion, when viewed in plan, is within the range of 25% to 100% of the thickness of the section adjacent to that section.

[0054] In the cooler according to the above embodiment, the wall portion varies so that the thickness of the section whose ends are substantially the same as the ends of the heat generating element in the flow path width direction is smaller than the thickness of the adjacent section, and so that the height of the section from the second surface is lower than the height of the adjacent section.

[0055] In the cooler according to the above embodiment, the top plate portion has a rectangular planar shape in plan view of the first surface, and the refrigerant flows in the longitudinal direction of the top plate portion.

[0056] The semiconductor module according to the above embodiment includes the above cooler, and a wiring board and a semiconductor element that are arranged on a third surface, which is the surface opposite to the first surface of the top panel portion of the cooler. [Industrial Applicability]

[0057] As described above, the present invention has the effect of improving the cooling performance of coolers applied to semiconductor modules, etc., and is particularly useful when applied to semiconductor modules that generate a large amount of heat during operation, such as those for industrial or electrical equipment use. [Explanation of symbols]

[0058] REFERENCE SIGNS LIST 1...cooler, 100...top plate, 120...water jacket, 121...bottom plate portion, 122...frame portion, 140...wall portion, 142, 146, 148...notched section, 2, 2A to 2C...heat generating element, 200...wiring board, 201...semiconductor element, 3...semiconductor module

Claims

1. a top plate portion that forms a first surface in a flow path of the refrigerant; a bottom plate portion that forms a second surface that faces the first surface in the coolant flow path; a plurality of protrusions disposed in the coolant flow path and protruding from the first surface toward the second surface; a frame portion that connects to the first surface and the second surface of the coolant flow path and forms a wall surface that surrounds the plurality of protrusions; a wall portion protruding in a direction from the second surface toward the first surface between a first protrusion and a second protrusion, the first protrusion and the second protrusion being spaced apart by a predetermined distance in a flow direction of the refrigerant in the refrigerant flow path, The wall portion is the second surface is connected to a pair of wall surfaces located at ends of a flow path width direction perpendicular to the flow direction of the refrigerant in a plan view, a section spaced apart from the first surface when viewed in the flow path width direction; cooler.

2. 2. The cooler according to claim 1, wherein the wall portion is provided in a region in the refrigerant flow path where no protrusions are arranged, between a first region in which a plurality of protrusions including the first protrusions are arranged and a second region in which a plurality of protrusions including the second protrusions are arranged.

3. The cooler of claim 1 , wherein the plurality of protrusions are spaced apart from the second surface.

4. 2. The cooler of claim 1, wherein the height of the wall portion from the second surface is within a range of 20% to 90% of the height of the refrigerant flow path from the second surface to the first surface at the position of the wall portion.

5. The cooler according to claim 1 , wherein the wall portion has a height varying from the second surface in the width direction of the flow passage.

6. The cooler of claim 5, wherein the wall portion varies so that the height of a section whose ends are substantially the same as the ends of the flow path width direction of a heat generating element arranged on the third surface, which is the backside of the first surface of the top plate portion, when viewed in a plane of the third surface, is lower than the height of a section adjacent to that section.

7. The cooler according to claim 6 , wherein the height of the section having both ends substantially at the same positions as both ends of the heat generating element in the flow path width direction varies in a V-shape along the flow path width direction.

8. 2. The cooler of claim 1, wherein the thickness of the wall portion from the downstream wall surface to the upstream wall surface of a section whose ends are substantially the same as both ends in the flow path width direction of the heat generating element arranged on the third surface, which is the backside of the first surface of the top plate portion, when viewed in a plane, is within the range of 25% to 100% of the thickness of the section adjacent to that section.

9. The wall portion is The thickness of the section having both ends substantially at the same positions as both ends of the heating element in the flow path width direction varies to be smaller than the thickness of the adjacent section, and The height of the section from the second surface varies to be lower than the height of the adjacent section. The cooler of claim 8.

10. The cooler according to claim 1 , wherein the top plate portion has a rectangular planar shape in a plan view of the first surface, and the refrigerant flows in a longitudinal direction of the top plate portion.

11. A cooler according to any one of claims 1 to 10; a wiring board and a semiconductor element disposed on a third surface, which is the surface opposite to the first surface of the top plate portion of the cooler.

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