Semiconductor device and water jacket

Abstract

The present invention suppresses pressure loss of a refrigerant, while improving cooling performance of a semiconductor element, in a semiconductor device and a water jacket. A semiconductor device (100) comprises a water jacket (110) for allowing a refrigerant (W) to flow between a heat dissipation base (30) that is joined to a substrate (20) on which a semiconductor element (10) is mounted and a surface (30b) which is on the opposite side of the heat dissipation base (30) from the substrate (20). A plurality of protrusions (112) of the water jacket (110) is arranged in both a first direction (D1) and a second direction (D2), which are orthogonal to a thickness direction (Dt) of the semiconductor element (10) and to each other. The plurality of protrusions protrude to the heat dissipation base (30) from a wall portion (111), which is provided parallel to the heat dissipation base (30). The first direction (D1) is the direction in which the refrigerant (W) flows, and the arrangement density of the plurality of protrusions (112) changes along the first direction (D1).

Description

Semiconductor device and water jacket

[0001] The present invention relates to a semiconductor device and a water jacket.

[0002] In a semiconductor device used in a power conversion device such as an inverter device, a method of using a water jacket for flowing a refrigerant between a heat dissipation base to which a substrate is joined for heat dissipation of a semiconductor element mounted on the substrate is known (for example, see Patent Documents 1 to 6). When the heat dissipation base has a flat plate shape, a protrusion protruding toward the heat dissipation base side may be provided on the water jacket.

[0003] Japanese Patent Application Laid-Open No. 2005-252151, Japanese Patent Application Laid-Open No. 2023-135202, Japanese Patent Application Laid-Open No. 2023-023518, Japanese Patent Application Laid-Open No. 2020-072106, Japanese Patent Application Laid-Open No. 2023-154856, Japanese Patent Application Laid-Open No. 2023-011395, Japanese Patent Application Laid-Open No. 2005-252026

[0004] As the semiconductor module is miniaturized, the cross-sectional area of the refrigerant flow path becomes smaller, and the pressure loss of the refrigerant due to the protrusion becomes significantly larger. Further, the larger the cross-sectional area of the refrigerant flow path, the lower the flow velocity of the refrigerant and the lower the cooling performance of the semiconductor element. An object of the present invention is to provide a semiconductor device and a water jacket capable of suppressing the pressure loss of the refrigerant while improving the cooling performance of the semiconductor element.

[0005] A semiconductor device according to an aspect of the present invention includes a semiconductor element, a substrate on which the semiconductor element is mounted, a heat dissipation base joined to the substrate, and a water jacket for flowing a refrigerant between a surface of the heat dissipation base opposite to the substrate. The water jacket has a wall portion facing a surface of the heat dissipation base opposite to the substrate, and a plurality of protrusions arranged in a first direction and a second direction that are orthogonal to the thickness direction of the semiconductor element and orthogonal to each other, and protruding from the wall portion toward the heat dissipation base side. The first direction is the direction in which the refrigerant flows, and the arrangement density of the plurality of protrusions changes along the first direction.

[0006] A water jacket in another aspect of the present invention is a water jacket for circulating a coolant between a heat dissipation base bonded to a substrate on which a semiconductor element is mounted and the surface opposite to the substrate, the water jacket having a wall portion facing the surface opposite to the substrate of the heat dissipation base, and a plurality of protrusions arranged in a first direction and a second direction that are perpendicular to the thickness direction of the semiconductor element and perpendicular to each other, and protruding from the wall portion toward the heat dissipation base. The first direction is the direction in which the coolant flows, and the arrangement density of the plurality of protrusions changes along the first direction.

[0007] According to the above embodiment, it is possible to suppress the pressure loss of the refrigerant while improving the cooling performance of the semiconductor element.

[0008] This is a front view showing the internal structure of the semiconductor device in this embodiment. This is a schematic diagram showing the structure of the water jacket in this embodiment. This is a graph showing the relationship between the position of the semiconductor element and its thermal resistance. This is a graph showing the pressure loss relative to the target value. This is a front view showing the shape of the protrusion in this embodiment. This is a front view showing the shape of the protrusion in a modified example of this embodiment.

[0009] The semiconductor device and water jacket according to this embodiment will be described below with reference to the drawings. It should be noted that the present invention is not limited to the embodiments described below, and can be implemented with appropriate modifications without changing its essence.

[0010] Figure 1 is a front view showing the internal structure of the semiconductor device in this embodiment. Figure 2 is a schematic diagram showing the structure of the water jacket in this embodiment. In addition, for the X, Y, and Z directions shown in Figures 1, 2, and Figures 5 and 6 described later, the thickness direction Dt of the semiconductor element 10 is defined as the Z direction, and of the X direction (first direction D1) and Y direction (second direction D2) which are orthogonal to the Z direction and mutually orthogonal to each other, the first direction D1 through which the refrigerant W flows is defined as the positive X direction. Furthermore, in some cases, the X direction may be called the left-right direction, the Y direction the front-back direction, and the Z direction the up-down direction. These directions are terms used for convenience of explanation, and the corresponding relationships of the X, Y, and Z directions will change depending on the mounting orientation of the semiconductor device 100.

[0011] The semiconductor device 100 according to this embodiment is applied to a power conversion device such as a power control unit, and is a power semiconductor device that constitutes an inverter circuit. The application of the semiconductor device 100 and the water jacket 110 is arbitrary, but for example, it is used as an inverter device for an automotive or industrial motor. The water jacket 110 may be called, for example, a cooler or cooling device.

[0012] The semiconductor device 100 shown in Figure 1 comprises a semiconductor module 1 and a water jacket 110. The semiconductor module 1 comprises, for example, six semiconductor elements 10 (10a to 10f), for example, three laminated substrates 20, and a heat dissipation base 30. The six semiconductor elements 10 and the three laminated substrates 20 are arranged in a straight line along the X direction. In this embodiment, the six semiconductor elements 10 (10a to 10f) are arranged in a straight line along the X direction, but the arrangement of the semiconductor elements 10 (10a to 10f) is not particularly limited.

[0013] The semiconductor elements 10 of the semiconductor module 1 shown in Figure 1 are mounted on a laminated substrate 20 (circuit board 22) by a bonding material S1, such as solder, and connected to other circuit boards 22 by conductive wires, metal wiring boards, etc. The semiconductor elements 10 are formed in a square or rectangular shape in plan view using a semiconductor substrate such as silicon (Si), silicon carbide (SiC), gallium nitride (GaN), and diamond.

[0014] Furthermore, an RC (Reverse Conducting)-IGBT element, which integrates an IGBT and a FWD, is used as the semiconductor element 10. Alternatively, switching elements such as IGBTs (Insulated Gate Bipolar Transistors) and power MOSFETs (Metal Oxide Semiconductor Field Effect Transistors), or diodes such as FWDs (Free Wheeling Diodes) may be used as the semiconductor element 10. In addition, power MOSFET elements, RB (Reverse Blocking)-IGBTs with sufficient voltage resistance against reverse bias may be used.

[0015] Each of the three laminated substrates 20 has two semiconductor elements 10 mounted on it. The laminated substrate 20 is an example of a substrate on which semiconductor elements 10 are mounted. The laminated substrate 20 is made of, for example, a DCB (Direct Copper Bonding) substrate, an AMB (Active Metal Brazing) substrate, or a metal base substrate. The laminated substrate 20 is formed, for example, in a rectangular shape in plan view. Each of the two laminated substrates 20 has an insulating plate 21, a circuit board 22, and a heat sink 23.

[0016] The insulating plate 21 is made of, for example, aluminum oxide (Al ２ O ３ ), aluminum nitride (AlN), silicon nitride (Si ３ N ４ ), aluminum oxide and zirconium oxide (ZrO ２ It is formed from a ceramic material such as a composite material with ), a resin material such as epoxy, or a sealing material such as an epoxy resin material using a ceramic material as a filler. The insulating plate 21 may also be called an insulating layer or insulating film.

[0017] The circuit board 22 is formed on the upper surface of the insulating board 21. The number of circuit boards 22 formed on the upper surface of a single insulating board 21 may be one or any other number. The circuit board 22 is a metal layer such as copper foil, and multiple such layers are formed on the insulating board 21 in an island-like manner, electrically insulated from each other. The circuit board 22 may also be called a circuit pattern, circuit layer, wiring board, wiring pattern, wiring layer, etc.

[0018] The heat sink 23 is formed on the lower surface of the insulating plate 21. The heat sink 23 may be made of a metal plate with good thermal conductivity, such as copper or aluminum. The heat sink 23 is joined to the upper surface 30a of the heat sink base 30 by a bonding material S2, such as solder. The heat sink 23 may also be called a heat sink layer.

[0019] As described above, the six semiconductor elements 10 and three laminated substrates 20 arranged on top of the heat dissipation base 30 constitute three sets of semiconductor units, for example, forming a three-phase inverter circuit, with two semiconductor elements 10 and one laminated substrate 20 forming one semiconductor unit. However, the number and configuration of the semiconductor elements 10 and laminated substrates 20 are not particularly limited.

[0020] Furthermore, a rectangular frame-shaped resin case is positioned on top of the heat dissipation base 30 so as to surround the six semiconductor elements 10 and the three laminated substrates 20, and a sealing material (for example, resin or gel) is filled into this case so as to cover the six semiconductor elements 10 and the three laminated substrates 20. This sealing material may be formed by transfer molding or by potting.

[0021] The heat dissipation base 30 is made of, for example, copper or aluminum. The heat dissipation base 30 may have a rectangular flat plate shape that extends in a first direction D1 (X direction) and a second direction D2 (Y direction) perpendicular to the thickness direction Dt of the semiconductor element 10. In this case, the upper surface 30a and lower surface 30b of the heat dissipation base 30 are planar.

[0022] As described above, the laminated substrate 20 (heat sink 23) is bonded to the upper surface 30a of the heat dissipation base 30 by the bonding material S2. The lower surface 30b of the heat dissipation base 30 is the surface opposite to the laminated substrate 20, and the coolant W flows between it and the water jacket 110, which will be described later. As described above, the lower surface 30b of the heat dissipation base 30 is planar (flat), but it may be provided with protrusions similar to the protrusions 112 of the water jacket 110, which will be described later.

[0023] The water jacket 110 is attached to the lower part of the heat dissipation base 30, for example, by fastening screws. The water jacket 110 is provided, for example, in the inverter case of an inverter device.

[0024] The water jacket 110 is made of a die-cast material such as an aluminum alloy (ADC12). The water jacket 110 has a rectangular parallelepiped shape with an opening at the top, and a coolant W flows inside. This coolant W flows in the first direction D1 (positive X direction) and heat is transferred from the heat dissipation base 30. The coolant W is, for example, cooling water, and is a liquid such as water containing additives such as antifreeze, rust inhibitors, and antioxidants. In order to ensure watertightness inside the water jacket 110, it is preferable to place a sealing material such as an O-ring between the upper edge of the water jacket 110 and the lower edge 30b of the heat dissipation base 30.

[0025] Inside the water jacket 110, there is a wall portion 111 that extends in the XY direction parallel to the heat dissipation base 30. The wall portion 111 faces the lower surface 30b of the heat dissipation base 30. An inclined portion 115 is provided on the negative X side of the wall portion 111. The inclined portion 115 has a width in the Y direction and is inclined on the positive X direction and the positive Z direction. An inclined portion 116 is provided on the positive X side of the wall portion 111. The inclined portion 116 has a width in the Y direction and is inclined on the positive X direction and the negative Z direction. That is, the wall portion 111, which is formed in a position sandwiched between the inclined portions 115 and 116, is located in a position that rises on the positive Z direction (towards the heat dissipation base 30) between the inlet passage 113 provided at the negative X end of the water jacket 110 and the discharge passage 114 provided at the positive X end (opposite side of the inlet passage 113) of the water jacket 110. Furthermore, the inclined section 115 is inclined from the introduction passage 113 toward the wall section 111, and the inclined section 116 is inclined from the discharge passage 114 toward the wall section 111. It is desirable that the wall section 111 be provided in a position close to the heat dissipation base 30 so that the refrigerant W flows near the lower surface 30b of the heat dissipation base 30.

[0026] The wall portion 111 is provided with a plurality of protrusions 112 that project toward the heat dissipation base 30 side (positive Z direction). As shown in Figure 2, these plurality of protrusions 112 are arranged in the first direction D1 (X direction) and the second direction D2 (Y direction). The protrusions 112 are provided, for example, integrally molded with the wall portion 111. The length of the protrusion 112 from the tip surface 112a to the root surface 112b (length in the Z direction), which will be described later, is preferably half or more of the length in the Z direction between the heat dissipation base 30 (lower surface 30b) and the wall portion 111 (flow path of the refrigerant W), and more preferably is approximately the same. The protrusions 112 can also be called convex portions, protruding portions, bosses, pin fins, etc.

[0027] Of the six semiconductor elements 10, the four central semiconductor elements 10b to 10e are positioned above the region (wall portion 111) where the protrusion 112 is provided. The semiconductor element 10a at the negative end in the X direction is positioned above the inclined portion 115. The semiconductor element 10f at the positive end in the X direction is positioned above the inclined portion 116.

[0028] Figure 5 is a front view showing the shape of the projection in this embodiment. As shown in Figures 2 and 5, the projection 112 is frustoconical in shape, and it is preferable that the tip on the heat dissipation base 30 side is a plane parallel to the XY direction. If the surface of the projection 112 on the heat dissipation base 30 side is the tip surface 112a and the surface on the wall portion 111 side is the root surface 112b, it is preferable that the diameter of the tip surface 112a is smaller than the diameter of the root surface 112b, and the area of ​​the tip surface 112a is smaller than the area of ​​the root surface 112b. By making the shape of the projection 112 a frustoconical, pressure loss and thermal resistance can be suppressed.

[0029] Figure 6 is a front view showing the shape of the projection in a modified example of this embodiment. As shown in the modified example in Figure 6, the projection 122 may be spherical in shape. In the case of a spherical shape, it is preferable that the diameter of the tip surface 122a is smaller than the diameter of the base surface 122b, and the area of ​​the tip surface 122a is smaller than the area of ​​the base surface 122b. Note that the shape of the projection 112 is not limited to the above, and may be other shapes such as a polygon when viewed in the thickness direction Dt. In this case as well, it is preferable that the projection is frustum-shaped, with the area of ​​the tip surface 112a being smaller than the area of ​​the base surface 112b.

[0030] Next, the arrangement of the protrusions 112 on the wall portion 111 will be explained using Figure 2. Two or three protrusions 112 are arranged at equal intervals in the second direction D2, and the multiple protrusions 112 arranged in the second direction D2 form five rows in the first direction D1. The multiple protrusions 112 are also arranged in a staggered pattern. It is preferable that the shape and size (size of the tip surface 112a and the base surface 112b, and the length in the Z direction) of all the protrusions 112 arranged on the wall portion 111 are equal. In the five rows of protrusions 112 in the first direction D1, the rows are numbered 1st, 2nd, ..., 5th in order from the negative side of the first direction D1. The interval between the nth row and the (n+1)th row is Pn (where n is a natural number between 1 and 4). The spacing between the nth row and the (n+1)th row is defined as the distance from the positive end of the root surface 112b of the nth row projection 112 on the D1 side to the negative end of the root surface 112b of the (n+1)th row projection 112 on the D1 side. As shown in Figure 2, the spacing between the rows of projections 112 is P1 > P2 > P3 > P4, and the spacing becomes narrower towards the positive side of the D1 side (downstream side of the refrigerant W).

[0031] As shown in Figure 2, the region where the projection 112 is provided (wall portion 111) includes the region directly below the four central semiconductor elements 10b to 10e among the six semiconductor elements 10 (i.e., the position in the first direction D1 and the second direction D2 is the same as that of the four semiconductor elements 10). The inclined portion 115 includes the region directly below semiconductor element 10a. The inclined portion 116 includes the region directly below semiconductor element 10f. Note that in Figure 2, the positions of the semiconductor elements 10 are indicated by dashed lines (imaginary lines).

[0032] Figure 3 is a graph showing the relationship between the position of semiconductor elements and thermal resistance. The horizontal axis of Figure 3 corresponds to the first direction D1 and semiconductor elements 10a to 10f, and the semiconductor elements on the right side of the horizontal axis are located further upstream of the refrigerant W. The vertical axis of Figure 3 shows the ratio when the target value of thermal resistance Rth is set to 1. Figure 4 is a graph showing the pressure loss relative to the target value. The vertical axis of Figure 4 shows the ratio when the target value of pressure loss Plus is set to 1.

[0033] Normally, when the flow velocity of the refrigerant W flowing through the water jacket 110 is constant, the refrigerant W whose temperature has risen due to heat dissipation from the semiconductor elements 10a and 10b located upstream flows downstream. Therefore, the thermal resistance Rth from the bonding material S1 that joins the semiconductor elements 10 and the laminated substrate 20 to the refrigerant W tends to increase further downstream. The protrusions 112 are arranged in the first direction D1 and the second direction D2, respectively, causing the refrigerant W to flow unevenly and increasing the flow velocity near the lower surface 30b of the heat dissipation base 30. Therefore, the flow velocity of the refrigerant W increases as the density of the protrusions 112 increases. Furthermore, it is known that the faster the flow velocity of the refrigerant W, the lower the thermal resistance Rth of the semiconductor elements 10. On the other hand, the pressure loss of the refrigerant W (the differential pressure between the inlet passage 113 and the outlet passage 114) Plus increases as the number (total number) of protrusions 112 provided on the wall portion 111 increases. In other words, if the density of the protrusions 112 is uniformly increased across the entire surface of the wall portion 111, the thermal resistance Rth can be reduced, but the pressure loss Plus will increase. Also, if the refrigerant W contains foreign matter, the more protrusions 112 provided on the wall portion 111 there are (total number), the more likely the foreign matter in the refrigerant W will clog, and the cooling performance will decrease.

[0034] Considering this trade-off relationship between thermal resistance Rth and pressure loss Plus, the water jacket 110 of the embodiment reduces thermal resistance Rth while suppressing pressure loss Plus by varying the arrangement density of the protrusions 112 along the first direction D1 and increasing the arrangement density in the areas where it is desired to reduce thermal resistance Rth. Specifically, as shown in Figure 2, the spacing between adjacent rows of protrusions 112 is narrowed towards the downstream side of the refrigerant W, thereby increasing the flow velocity of the refrigerant W downstream. Therefore, as shown in Figure 3, the thermal resistance Rth of all semiconductor elements 10a to 10f arranged along the first direction D1 can be set to below the target value.

[0035] Furthermore, in the embodiment, the water jacket 110 increases the arrangement density of the protrusions 112 by narrowing the spacing between rows of adjacent protrusions 112, thus increasing the arrangement density without increasing the number of multiple protrusions 112 arranged in the second direction. This suppresses the accumulation of foreign matter between multiple protrusions 112 while suppressing the pressure loss Plus. In addition, the water jacket 110 has an inclined portion 115 connected to the negative end of the wall portion 111 in the first direction D1, so that the flow velocity increases when the refrigerant W flows from the introduction passage 113 into the wall portion 111. Also, an inclined portion 116 is connected to the positive end of the wall portion 111 in the first direction D1, suppressing a decrease in flow velocity when the refrigerant W flows out from the wall portion 111 towards the discharge passage 114. Therefore, as shown in Figure 4, the pressure loss Plus can be kept below the target value. Furthermore, the inclined portions 115 and 116 ensure the flow velocity necessary for cooling the semiconductor element 10, thereby reducing the thermal resistance of the semiconductor elements 10a and 10f located outside the wall portion 111 in the first direction D1.

[0036] Specific values ​​such as the angle of the inclined portion 115 with respect to the first direction D1, the angle of the inclined portion 116 with respect to the first direction D1, the height from the wall portion 111 to the lower surface 30b of the heat dissipation base 30, and the length of the protrusion 112 in the Z direction, as well as the degree of change in the arrangement density of the protrusions 112 along the first direction D1 (number of protrusions 112 arranged in the D2 direction, number of rows n of protrusions 112 arranged in the first direction D1, value of the spacing Pn, etc.), are set according to the target values ​​of the thermal resistance Rth and pressure loss Plus required for the semiconductor device 100. These target values ​​are set as needed depending on the semiconductor elements 10 mounted on the semiconductor device 100 and the application, and are not defined by standards or anything like that.

[0037] As described above, the semiconductor device 100 of this embodiment comprises a semiconductor element 10, a laminated substrate 20 which is an example of a substrate on which the semiconductor element 10 is mounted, a heat dissipation base 30 bonded to the laminated substrate 20, and a water jacket 110 for flowing a coolant W between the heat dissipation base 30 and the surface (bottom surface 30b) of the heat dissipation base 30 opposite to the laminated substrate 20. The water jacket 110 has a wall portion 111 facing the surface of the heat dissipation base 30 opposite to the laminated substrate 20, and a plurality of protrusions 112 arranged in a first direction D1 and a second direction D2 which are perpendicular to the thickness direction Dt of the semiconductor element 10 and are mutually perpendicular, and which protrude from the wall portion 111 toward the heat dissipation base 30. The first direction D1 is the direction in which the coolant W flows, and the arrangement density of the plurality of protrusions 112 changes along the first direction D1.

[0038] Thus, according to this embodiment, by changing the arrangement density of the protrusions 112 along the first direction D1, the flow velocity of the refrigerant W can be changed depending on the position in the first direction D1. That is, the arrangement density of the protrusions 112 is increased at the position where it is desired to reduce the thermal resistance Rth. Therefore, it is possible to reduce the thermal resistance of the semiconductor element 10 while suppressing the pressure loss of the refrigerant W. Furthermore, according to this embodiment, it is only necessary to adjust the arrangement density of the protrusions 112 in the first direction D1, and without complicating the structure of the water jacket 110 or the structure of the flow path of the refrigerant W inside it, it is possible to reduce the thermal resistance of the semiconductor element 10 while suppressing the pressure loss of the refrigerant W, as described above.

[0039] Furthermore, in this embodiment, the arrangement density of the multiple protrusions 112 is greater downstream of the refrigerant W than upstream. This allows the velocity of the refrigerant W, whose temperature has risen due to heat dissipation from the semiconductor element 10 as it passes beneath it, to increase downstream. Therefore, the thermal resistance of the semiconductor element 10 downstream can be reduced.

[0040] Furthermore, in this embodiment, the arrangement density of the multiple protrusions 112 gradually increases from the upstream side to the downstream side of the refrigerant W. This allows the velocity of the refrigerant W to be gradually increased from the upstream side to the downstream side. Therefore, the thermal resistance of each semiconductor element 10 can be reduced from the upstream side to the downstream side, and the cooling performance of the semiconductor element 10 can be adjusted in stages at each position in the first direction D1.

[0041] Furthermore, in this embodiment, the spacing Pn between adjacent protrusions 112 in the first direction D1 is narrower in at least a portion of the downstream side of the refrigerant W than on the upstream side of the refrigerant W. This allows the arrangement density of the multiple protrusions 112 to be increased downstream of the refrigerant W compared to upstream. Therefore, the velocity of the refrigerant W, whose temperature has risen due to heat dissipation from the semiconductor element 10 by passing under the upstream semiconductor element 10, can be increased downstream. Thus, the cooling performance of the semiconductor element 10 downstream can be improved. In addition, the length (Z direction) from the tip surface 112a to the root surface 112b of the protrusion 112 is preferably more than half, and more preferably approximately the same as, the length in the Z direction between the heat dissipation base 30 (bottom surface 30b) and the wall portion 111 (flow path of refrigerant W). This brings the distance between the protrusion 112 and the heat dissipation base 30 closer, allowing the flow velocity near the bottom surface 30b of the heat dissipation base 30 to be increased. Thus, the cooling performance of the semiconductor element 10 can be further improved.

[0042] Furthermore, in this embodiment, the spacing Pn between the multiple protrusions 112 in the first direction D1 gradually narrows from the upstream side to the downstream side of the refrigerant W. As a result, the arrangement density of the multiple protrusions 112 gradually increases from the upstream side to the downstream side of the refrigerant W. This allows the velocity of the refrigerant W to be gradually increased from the upstream side to the downstream side. Therefore, the thermal resistance of each semiconductor element 10 can be reduced from the upstream side to the downstream side, and the cooling performance of the semiconductor element 10 can be adjusted in stages at each position in the first direction D1. In addition, since the arrangement density of the multiple protrusions 112 arranged in the second direction D2 is increased without increasing the number of protrusions 112, it is possible to suppress pressure loss Plus while preventing foreign matter contained in the refrigerant W from getting stuck between the multiple protrusions 112.

[0043] Also, in the present embodiment, the water jacket 110 further has inclined portions 115 and 116 at both ends of the wall portion 111 in the first direction D1, and at least one semiconductor element 10 is disposed above the inclined portions 115 and 116. Thereby, since the flow velocity of the refrigerant W below the semiconductor elements 10a and 10f is increased by the inclined portions 115 and 116, the thermal resistance of the semiconductor elements 10a and 10f disposed outside the wall portion 111 in the first direction D1 can be reduced. Therefore, the semiconductor element 10 can be disposed not only above the wall portion 111.

[0044] Also, in the present embodiment, the shapes and sizes of the plurality of protrusions 112 are substantially the same. That is, all the protrusions 112 disposed on the wall portion 111 have the same shape and size, and it is not necessary to use protrusions having different shapes depending on the position or different diameters of the tip surfaces 112a or lengths in the Dt direction even if they have the same shape. Thereby, it is possible to suppress the pressure loss of the refrigerant W while reducing the thermal resistance of the semiconductor element 10 without using a complicated structure.

[0045] Also, in the present embodiment, the area of the tip surface 112a on the heat dissipation base 30 side of the plurality of protrusions 112 is smaller than the area of the base surface 112b on the wall portion 111 side of the protrusions 112. Further, as shown in FIG. 5, the shape of the plurality of protrusions 112 has a frustum of a cone shape. Also, in a modified example of the present embodiment, as shown in FIG. 6, the shape of the plurality of protrusions 122 is a frustum of a sphere. With these structures, an inclined portion can be formed with respect to the flow direction of the refrigerant W, so that the refrigerant W is guided to the positive side in the Z direction by the protrusions 112 and 122, and the flow velocity near the lower surface 30b of the heat dissipation base 30 can be increased. Therefore, the cooling performance of the semiconductor element 10 can be further improved.

[0046] The above-described embodiments are shown as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalent scope thereof.

[0047] The following are some of the inventions described in the specification and drawings of this application.

[0048] <Note 1> A semiconductor device comprising: a semiconductor element; a substrate on which the semiconductor element is mounted; a heat dissipation base bonded to the substrate; and a water jacket for flowing a coolant between the heat dissipation base and the surface opposite to the substrate, wherein the water jacket has a wall portion facing the surface of the heat dissipation base opposite to the substrate, and a plurality of protrusions arranged in a first direction and a second direction that are perpendicular to the thickness direction of the semiconductor element and perpendicular to each other, and protruding from the wall portion toward the heat dissipation base, wherein the first direction is the direction in which the coolant flows, and the arrangement density of the plurality of protrusions changes along the first direction.

[0049] <Note 2> The semiconductor device according to Note 1, characterized in that the arrangement density of the plurality of protrusions is greater downstream of the refrigerant than upstream.

[0050] <Note 3> The semiconductor device according to Note 1, characterized in that the arrangement density of the plurality of protrusions gradually increases from the upstream side to the downstream side of the refrigerant.

[0051] <Note 4> The semiconductor device according to Note 1, characterized in that the spacing between the plurality of adjacent protrusions in the first direction is narrower than that on the upstream side of the refrigerant in at least a portion of the downstream side of the refrigerant.

[0052] <Note 5> The semiconductor device according to Note 1, characterized in that the spacing between the plurality of adjacent protrusions in the first direction gradually narrows from the upstream side to the downstream side of the refrigerant.

[0053] <Note 6> The semiconductor device according to any one of Notes 1 to 5, wherein the water jacket further has inclined portions at both ends of the wall portion in the first direction, and at least one semiconductor element is arranged above the inclined portion.

[0054] <Note 7> The semiconductor device according to any one of Notes 1 to 6, characterized in that the shape and size of the plurality of protrusions are substantially the same.

[0055] <Note 8> The semiconductor device according to Note 7, characterized in that the area of ​​the tip surface of the plurality of protrusions on the heat dissipation base side is larger than the area of ​​the root surface of the protrusions on the wall side.

[0056] <Note 9> The semiconductor device according to Note 8, characterized in that the plurality of protrusions have the shape of a frustocone.

[0057] <Note 10> A water jacket for circulating a coolant between a heat dissipation base bonded to a substrate on which a semiconductor element is mounted and the surface opposite to the substrate, the water jacket having a wall portion facing the surface opposite to the substrate of the heat dissipation base, and a plurality of protrusions arranged in a first direction and a second direction which are perpendicular to the thickness direction of the semiconductor element and are mutually perpendicular, and which protrude from the wall portion toward the heat dissipation base, wherein the first direction is the direction in which the coolant flows, and the arrangement density of the plurality of protrusions changes along the first direction.

[0058] As described above, the present invention has the effect of improving the cooling performance of semiconductor elements while suppressing the pressure loss of the refrigerant in semiconductor devices and water jackets, and is particularly useful in inverter devices for industrial or electrical equipment.

[0059] This application is based on Japanese Patent Application No. 2024-181424, filed on October 17, 2024. All of its contents are included herein.

[0060] 1 Semiconductor module 10, 10a, 10b, 10c, 10d, 10e, 10f Semiconductor element 20 Laminated substrate (substrate) 21 Insulating board 22 Circuit board 23 Heat sink 30 Heat sink base 30a Top surface 30b Bottom surface 100 Semiconductor device 110 Water jacket 111 Wall portion 112 Protrusion 112a Tip surface 112b Base surface 113 Inlet path 114 Outlet path 122 Protrusion 122a Tip surface 112b Base surface Dt Thickness direction D1 First direction D2 Second direction S1, S2 Bonding material W Refrigerant

Claims

1. A semiconductor device comprising: a semiconductor element; a substrate on which the semiconductor element is mounted; a heat dissipation base bonded to the substrate; and a water jacket for circulating a coolant between the heat dissipation base and the surface opposite to the substrate, wherein the water jacket has a wall portion facing the surface of the heat dissipation base opposite to the substrate, and a plurality of protrusions arranged in a first direction and a second direction that are perpendicular to the thickness direction of the semiconductor element and mutually perpendicular, and projecting from the wall portion toward the heat dissipation base, wherein the first direction is the direction in which the coolant flows, and the arrangement density of the plurality of protrusions changes along the first direction.

2. The semiconductor device according to claim 1, characterized in that the arrangement density of the plurality of protrusions is greater downstream of the refrigerant than upstream of it.

3. The semiconductor device according to claim 1, characterized in that the arrangement density of the plurality of protrusions gradually increases from the upstream side to the downstream side of the refrigerant.

4. The semiconductor device according to claim 1, characterized in that the spacing between the plurality of adjacent protrusions in the first direction is narrower on the upstream side of the refrigerant in at least a portion of the downstream side of the refrigerant than on the upstream side of the refrigerant.

5. The semiconductor device according to claim 1, characterized in that the spacing between the plurality of adjacent protrusions in the first direction gradually narrows from the upstream side to the downstream side of the refrigerant.

6. The semiconductor device according to claim 3, wherein the water jacket further has inclined portions at both ends of the wall portion in the first direction, and at least one semiconductor element is arranged above the inclined portion.

7. The semiconductor device according to claim 3, characterized in that the shape and size of the plurality of protrusions are substantially the same.

8. The semiconductor device according to claim 3, characterized in that the area of ​​the tip surface of the plurality of protrusions on the heat dissipation base side is smaller than the area of ​​the root surface of the protrusion on the wall side.

9. The semiconductor device according to claim 8, characterized in that the plurality of protrusions have a frustoconical shape.

10. A water jacket for circulating a coolant between a heat dissipation base bonded to a substrate on which a semiconductor element is mounted and the surface opposite to the substrate, the water jacket having a wall portion facing the surface opposite to the substrate of the heat dissipation base, and a plurality of protrusions arranged in a first direction and a second direction that are perpendicular to the thickness direction of the semiconductor element and perpendicular to each other, and projecting from the wall portion toward the heat dissipation base, wherein the first direction is the direction in which the coolant flows, and the arrangement density of the plurality of protrusions changes along the first direction.

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