Cooler and semiconductor device

Abstract

This cooler has a flow path through which a cooling medium flows, and cools a plurality of cooling targets, wherein: the flow path is divided into a plurality of continuous sections in a main flow direction in which the cooling medium flows; when viewed from an orthogonal direction, which is a direction orthogonal to the main flow direction, each section has a high flow path resistance region having a relatively high flow path resistance and a low flow path resistance region having a flow path resistance that is relatively lower than that of the high flow path resistance region; in a specific section, which is a section for cooling a specific cooling target that is one of the cooling targets, the low flow path resistance region is disposed in a position overlapping the specific cooling target when viewed from the orthogonal direction, and the high flow path resistance region is disposed in a position not overlapping the specific cooling target; and when viewed from the orthogonal direction, in at least one section positioned on the upstream side of the specific section, the high flow path resistance region is disposed in a position overlapping the cooling target, and the low flow path resistance region is disposed in a position not overlapping the cooling target.

Description

Cooler and semiconductor device

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

[0002] For example, Patent Document 1 discloses a power semiconductor device including a finned base plate and a power semiconductor element. The power semiconductor element is bonded to the finned base plate via an insulating substrate. Patent Document 1 also discloses a configuration in which heat dissipation fins are concentrated directly below the power semiconductor element.

[0003] Patent No. 5046378

[0004] Incidentally, a semiconductor device such as the power semiconductor device disclosed in Patent Document 1 includes a plurality of cooling targets such as power semiconductor elements. These cooling targets are arranged, for example, in the flow direction (main flow direction) of the cooling medium in the flow path. The temperature of the cooling medium that receives heat from these cooling targets increases toward the downstream side of the main flow direction. For this reason, it may be difficult to sufficiently cool the cooling targets located downstream of the main flow direction.

[0005] The present invention has been made in consideration of the above-mentioned problems, and aims to improve the cooling performance of a cooler having a flow path through which a cooling medium flows and cooling multiple cooling objects, for cooling objects located downstream in the flow direction of the cooling medium.

[0006] The present invention employs the following configuration as a means for solving the above problems.

[0007] A first aspect of the present invention is a cooler having a flow path through which a cooling medium flows and cooling a plurality of cooling objects, wherein the flow path is divided into a plurality of continuous compartments in the main flow direction of the cooling medium, and each compartment has a high flow path resistance region in which the flow path resistance is relatively high and a low flow path resistance region in which the flow path resistance is relatively lower than that of the high flow path resistance region, when viewed from an orthogonal direction that is perpendicular to the main flow direction, and in a specific compartment which cools a specific cooling object that is one of the cooling objects, when viewed from the orthogonal direction, the low flow path resistance region is arranged in a position overlapping with the specific cooling object, and the high flow path resistance region is arranged in a position not overlapping with the specific cooling object, and in at least one of the compartments located upstream of the specific compartment, when viewed from the orthogonal direction, the high flow path resistance region is arranged in a position overlapping with the cooling object, and the low flow path resistance region is arranged in a position not overlapping with the cooling object.

[0008] A second aspect of the present invention is a semiconductor device, which includes the cooler of the first aspect and a semiconductor element that is the object to be cooled and that is cooled by the cooler.

[0009] In the present invention, in a section located upstream in the mainstream direction, the cooling medium is less likely to flow directly below the cooling object, but is more likely to flow in a position that avoids being directly below the cooling object. Furthermore, in a specific section located downstream in the mainstream direction, the cooling medium is more likely to flow directly below the cooling object, but is less likely to flow in a position that avoids being directly below the cooling medium. Therefore, the present invention can supply the cooling medium directly below the specific cooling object in the specific section while suppressing the temperature information of the cooling medium, thereby improving the cooling performance for the specific cooling object located downstream. In other words, the present invention can improve the cooling performance for the cooling object located downstream in the cooling medium flow direction in a cooler that has a flow path through which the cooling medium flows and cools multiple cooling objects.

[0010] While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments and is not to be limited to the disclosed exemplary embodiments.

[0011] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a cooler and a semiconductor device according to the present invention will be described below with reference to the drawings.

[0012] First Embodiment FIG. 1 is a schematic plan view showing the general configuration of a cooler 1 of this embodiment. FIG. 2 is a schematic cross-sectional view showing the general configuration of the cooler 1 of this embodiment. Note that FIG. 2 is a cross-sectional view taken along line A-A in FIG. 1. The cooler 1 of this embodiment cools, for example, a plurality of heat-generating components X (targets to be cooled) placed on the upper surface. The cooler 1 of this embodiment includes a flow path R through which a cooling medium Y flows. The cooler 1 of this embodiment cools the heat-generating components X by heat exchange between the heat-generating components X and the cooling medium Y. In other words, the cooler 1 of this embodiment includes the flow path R through which the cooling medium Y flows and cools the plurality of heat-generating components X. As shown in FIGS. 1 and 2, the cooler 1 of this embodiment includes a housing 2 and cooling pins 3.

[0013] The housing 2 has a flow path R formed therein through which the cooling medium Y flows, and is made of, for example, a metal material with high thermal conductivity. The housing 2 has a coolant supply port 2a for supplying the cooling medium Y to the flow path R, and a coolant discharge port 2b for discharging the cooling medium Y from the flow path R. As shown in FIG. 1 , the coolant supply port 2a and the coolant discharge port 2b are disposed opposite each other with the flow path R sandwiched therebetween.

[0014] In the flow path R of the housing 2, the cooling medium Y flows from the refrigerant supply port 2 a to the refrigerant discharge port 2 b. That is, in the flow path R, the cooling medium Y flows with the refrigerant supply port 2 a side as the upstream side and the refrigerant discharge port 2 b side as the downstream side.

[0015] In the following description, the direction connecting the upstream and downstream of the flow path R (i.e., in this embodiment, the direction connecting the refrigerant supply port 2a and the refrigerant discharge port 2b) is referred to as the mainstream direction. Furthermore, the direction along the width of the flow path R (the width direction of the flow path R perpendicular to the mainstream direction) is referred to as the flow path width direction. Note that the installation posture of the cooler 1 is not particularly limited, but for convenience of description, the direction perpendicular to the mainstream direction and the flow path width direction is referred to as the up-down direction (perpendicular direction). Furthermore, one side of the flow path width direction is referred to as the right side, and the other side of the flow path width direction is referred to as the left side.

[0016] 2, in this embodiment, the housing 2 includes a main body 2c and an upper wall 2d. The main body 2c is formed in the shape of a box-shaped container with an open top. The main body 2c is formed with the refrigerant supply port 2a and the refrigerant discharge port 2b.

[0017] The upper wall portion 2d is fixed to the upper end of the main body portion 2c and forms the upper portion of the housing 2. The upper wall portion 2d forms the flow path R together with the main body portion 2c. In this embodiment, the upper surface of the upper wall portion 2d is the surface on which the heat-generating component X is placed. The lower surface of the upper wall portion 2d is the surface on which the cooling pins 3 are formed. In other words, the cooling pins 3 are formed so as to connect to the lower surface of the upper wall portion 2d. The upper wall portion 2d is, for example, integrally molded with the cooling pins 3.

[0018] A plurality of cooling pins 3 are provided. These cooling pins 3 are located inside the flow path R. These cooling pins 3 are formed, for example, from the same material as the housing 2. In this embodiment, each cooling pin 3 is formed to extend downward from the lower surface of the upper wall portion 2 d.

[0019] That is, the cooler 1 of this embodiment includes a plurality of cooling pins 3 that are arranged to extend in the same direction in the flow path R. In this embodiment, the extension direction of the cooling pins 3 is the vertical direction. Each cooling pin 3 protrudes the same amount from the upper wall portion 2d. That is, in this embodiment, each cooling pin 3 has the same vertical dimension. However, the vertical dimensions of the plurality of cooling pins 3 may differ from one another.

[0020] 1 , the cooler 1 of this embodiment is provided with a plurality of heat-generating components X along the main flow direction. Specifically, in this embodiment, six heat-generating components X are provided for the cooler 1.

[0021] 1, in the cooler 1 of this embodiment, the flow path R is divided into a plurality of continuous compartments 4. In this embodiment, no members for isolating the compartments 4, such as partition walls, are installed at the boundaries between the compartments 4.

[0022] One heat-generating component X is provided in each section 4. In other words, one section 4 is assigned to each of the multiple heat-generating components X arranged in the main flow direction. Therefore, in this embodiment, six sections 4 are provided, the same number as the heat-generating components X.

[0023] Each section 4 is provided with a dense region 5 and a sparse region 6. The dense region 5 is a region in which the cooling pins 3 are arranged more densely than the sparse region 6 when viewed from the top-bottom direction. The sparse region 6 is a region in which the cooling pins 3 are arranged more sparsely than the dense region 5 when viewed from the top-bottom direction. In other words, the dense region 5 is a region in which the cooling pins 3 are arranged at a relatively high density, and the sparse region 6 is a region in which the cooling pins 3 are arranged at a relatively low density.

[0024] The dense region 5 has a higher flow path resistance than the sparse region 6 because the cooling pins 3 are arranged more densely in the dense region 5 than in the sparse region 6. The sparse region 6 has a higher flow path resistance than the dense region 5 because the cooling pins 3 are arranged more sparsely in the dense region 5. In other words, the dense region 5 is a high flow path resistance region where the flow path resistance is relatively high. The sparse region 6 is a low flow path resistance region where the flow path resistance is relatively low.

[0025] In this embodiment, the section 4 located furthest downstream in the main flow direction among the multiple sections 4 is referred to as the most downstream section 4a (specific section). The heat-generating component X cooled in the most downstream section 4a is referred to as the most downstream heat-generating component Xa (specific cooling target). As shown in FIG. 1 , in the sections 4 other than the most downstream section 4a, the dense regions 5 are positioned so as to overlap with the heat-generating component X when viewed from above, and the sparse regions 6 are positioned so as not to overlap with the heat-generating component X when viewed from above. In other words, in the sections 4 other than the most downstream section 4a, the area directly below the heat-generating component X is a high flow path resistance region.

[0026] 1, in the most downstream section 4a, the dense region 5 is arranged in a position that does not overlap with the heat-generating component X (the most downstream heat-generating component Xa) when viewed from above, and the sparse region 6 is arranged in a position that overlaps with the heat-generating component X (the most downstream heat-generating component Xa) when viewed from above. In other words, in the most downstream section 4a, the area directly below the heat-generating component X is a low flow path resistance area.

[0027] In this embodiment, the multiple heat-generating components X arranged along the main flow direction are arranged alternately left and right along the main flow direction. That is, when the most upstream heat-generating component X is located on the left side, the second most upstream heat-generating component X is located on the right side, the third most upstream heat-generating component X is located on the left side, the fourth most upstream heat-generating component X is located on the right side, the fifth most upstream heat-generating component X is located on the left side, and the most downstream heat-generating component X (the most downstream heat-generating component Xa) is located on the right side.

[0028] Therefore, in this embodiment, the dense region 5 is located on the left side in the section 4 located most upstream, the dense region 5 is located on the right side in the section 4 located second from the upstream side, the dense region 5 is located on the left side in the section 4 located third from the upstream side, the dense region 5 is located on the right side in the section 4 located fourth from the upstream side, the dense region 5 is located on the left side in the section 4 located fifth from the upstream side, and the dense region 5 is located on the left side in the section 4 located most downstream (the most downstream section 4a).

[0029] That is, as shown in FIG. 1 , in the cooler 1 of this embodiment, in the sections 4 that are continuous in the mainstream direction, the arrangement order of the dense regions 5 and the sparse regions 6 in the section 4 located upstream in the mainstream direction is reversed to the arrangement order of the dense regions 5 and the sparse regions 6 in the section 4 located downstream in the mainstream direction.

[0030] In this embodiment, the sparse regions 6 (low flow resistance regions) of consecutive sections 4 in the mainstream direction are partially connected directly to each other. That is, the sparse region 6 of the section 4 located most upstream and the sparse region 6 of the section 4 located second from the upstream side partially overlap when viewed from the mainstream direction and are directly connected to each other. Furthermore, the sparse region 6 of the section 4 located second from the upstream side and the sparse region 6 of the section 4 located third from the upstream side partially overlap when viewed from the mainstream direction and are directly connected to each other. Furthermore, the sparse region 6 of the section 4 located third from the upstream side and the sparse region 6 of the section 4 located fourth from the upstream side partially overlap when viewed from the mainstream direction and are directly connected to each other. Furthermore, the sparse region 6 of the section 4 located fourth from the upstream side and the sparse region 6 of the section 4 located fifth from the upstream side partially overlap when viewed from the mainstream direction and are directly connected to each other. In addition, the sparse region 6 of the section 4 located fifth from the upstream side and the sparse region 6 of the section located most downstream (the most downstream section 4a) overlap when viewed from the mainstream direction and are directly connected to each other.

[0031] In the cooler 1 of this embodiment, the cooling medium Y flows more in the sparse regions 6 than in the dense regions 5 in each of the sections 4. Therefore, as shown in Fig. 1, in the section 4 upstream of the most downstream section 4a, the flow rate of the cooling medium Y at a position away from the heat-generating component X is greater than that directly below the heat-generating component X. Therefore, in the section 4 upstream of the most downstream section 4a, heat exchange between the cooling medium Y and the heat-generating component X is suppressed.

[0032] On the other hand, in the most downstream section 4a, the flow rate of the cooling medium Y directly below the most downstream heat-generating component Xa is greater than that at a position farther away from the heat-generating component X. Therefore, in the most downstream section 4a, heat exchange between the cooling medium Y and the most downstream heat-generating component Xa is promoted.

[0033] In the cooler 1 of this embodiment, most of the cooling medium Y flowing from the cooling medium supply port 2 a toward the cooling medium discharge port 2 b flows in a serpentine manner as shown in Fig. 1. However, not all of the cooling medium Y passes through the sparse region 6, but some of the cooling medium Y passes through the dense region 5.

[0034] The cooler 1 of this embodiment, as described above, has a flow path R through which a cooling medium Y flows and cools a plurality of heat-generating components X. The flow path R is divided into a plurality of continuous compartments 4 in the main flow direction of the cooling medium Y. Each compartment 4 has a dense region 5 with a relatively high flow path resistance and a sparse region 6 with a relatively lower flow path resistance than the dense region 5, as viewed from above and below, which is a direction perpendicular to the main flow direction. Furthermore, in the most downstream compartment 4a, which is the compartment 4 that cools the most downstream heat-generating component Xa, one of the heat-generating components X, the sparse region 6 is arranged in a position overlapping the most downstream heat-generating component Xa, as viewed from above and below, and the dense region 5 is arranged in a position not overlapping the most downstream heat-generating component Xa. In at least one compartment 4 located upstream of the most downstream compartment 4a, the dense region 5 is arranged in a position overlapping the heat-generating component X, as viewed from above and below, and the sparse region 6 is arranged in a position not overlapping the heat-generating component X.

[0035] In the cooler 1 of this embodiment, in the section 4 located upstream of the most downstream section 4a, the cooling medium Y is less likely to flow directly below the heat-generating component X, but is more likely to flow in a position that avoids being directly below the heat-generating component X. Also, in the most downstream section 4a, the cooling medium Y is more likely to flow directly below the heat-generating component X, but is less likely to flow in a position that avoids being directly below the cooling medium Y. Therefore, the cooler 1 of this embodiment can supply the cooling medium Y to directly below the most downstream heat-generating component Xa in the most downstream section 4a while suppressing a temperature rise in the cooling medium Y, thereby improving the cooling performance for the most downstream heat-generating component Xa located downstream.

[0036] In other words, the cooler 1 of this embodiment can flow the components of the cooling medium Y that are not significantly affected by heat just below the most downstream heat-generating component Xa, thereby suppressing thermal interference, a phenomenon in which the temperature of the upstream heat-generating component X affects the downstream heat-generating component X.

[0037] In addition, when the heat-generating components X are identical, the cooler 1 of this embodiment can equalize the temperatures of the heat-generating components X. For example, if the cooling pins 3 are evenly arranged in all sections 4, the temperature of the cooling medium Y increases significantly downstream. As a result, the temperature of the most upstream heat-generating component X drops significantly, making it difficult to lower the temperature of the most downstream heat-generating component Xa. A device equipped with heat-generating components X must be designed to withstand heat depending on the most downstream heat-generating component Xa, which has the highest temperature. Therefore, if it is difficult to lower the temperature of the most downstream heat-generating component Xa, it may be necessary to improve the heat resistance of the entire device or to reduce the power supply to the heat-generating component X. In contrast, the cooler 1 of this embodiment can equalize the temperatures of the heat-generating components X and lower the temperature of the most downstream heat-generating component Xa. Therefore, the cooler 1 of this embodiment can ease the need for heat countermeasures and increase the amount of power supplied to the heat-generating component X.

[0038] Furthermore, in the cooler 1 of this embodiment, each compartment 4 is provided with a sparse region 6. Therefore, the overall flow path resistance of each compartment 4 can be reduced compared to when each compartment 4 is entirely made up of a dense region 5 or the like. Therefore, the cooler 1 of this embodiment can reduce the overall flow path resistance and reduce pressure loss. In this way, the cooler 1 of this embodiment can reduce pressure loss and lower the temperature of the most downstream heat-generating component Xa, which has the highest temperature.

[0039] In the present embodiment, the description has been given assuming that the most downstream heat-generating component Xa, which is cooled in the most downstream section 4a, is the component that is most likely to reach a high temperature among the plurality of heat-generating components X. For this reason, the cooler 1 of the present embodiment is configured to enhance the cooling performance of the section 4 that is located most downstream in the main flow direction among the plurality of sections 4. However, the heat-generating component X whose cooling performance needs to be improved is not necessarily located most downstream.

[0040] For example, when different types of heat-generating components X are provided, the heat generation amounts of the heat-generating components X arranged along the main flow direction may be locally large except for the most downstream heat-generating component X. In such a case, in order to improve the cooling performance for the heat-generating component X with a large heat generation amount, in the section 4 that cools the heat-generating component X with a large heat generation amount, the sparse region 6 may be arranged so as to overlap with the heat-generating component X when viewed from above, and the dense region 5 may be arranged so as not to overlap with the heat-generating component X when viewed from above. In this case, in the section 4 further upstream, the dense region 5 may be arranged so as to overlap with the heat-generating component X when viewed from above, and the sparse region 6 may be arranged so as not to overlap with the heat-generating component X when viewed from above.

[0041] In addition, in the cooler 1 of this embodiment, in the section 4 located one section upstream of the most downstream section 4a in the mainstream direction, the sparse region 6 is the region connected to the sparse region 6 of the most downstream section 4a from the upstream side in the mainstream direction.

[0042] In the cooler 1 of this embodiment, the cooling medium Y is more likely to flow toward the sparse region 6 of the most downstream section 4 a. Therefore, the cooler 1 of this embodiment can more efficiently cool the most downstream heat-generating component Xa.

[0043] Furthermore, in the cooler 1 of this embodiment, the sparse regions 6 of the sections 4 that are consecutive in the mainstream direction are connected to each other. In the cooler 1 of this embodiment, the cooling medium Y can pass through the sparse regions 6 that are connected to each other. This allows the cooling medium Y to flow smoothly up to the most downstream section 4a. Therefore, the cooler 1 of this embodiment can further reduce pressure loss.

[0044] Furthermore, in the cooler 1 of this embodiment, in the sections 4 that are continuous in the mainstream direction, the arrangement order of the dense regions 5 and sparse regions 6 in the section 4 located upstream in the mainstream direction is reversed to the arrangement order of the dense regions 5 and sparse regions 6 in the section 4 located downstream in the mainstream direction.

[0045] In the cooler 1 of this embodiment, the cooling medium Y flowing from the upstream side to the downstream side can be made to meander in the main flow direction. This prevents the heat of the heat-generating component X cooled in the upstream section 4 of the sections 4 that are continuous in the main flow direction from affecting the cooling of the heat-generating component X cooled in the downstream section 4. Furthermore, the cooling medium Y can be made to flow so as to hit the dense region 5, preventing an extreme decrease in the flow rate of the cooling medium Y to the dense region 5.

[0046] Furthermore, in the cooler 1 of this embodiment, the dense region 5 is formed by increasing the arrangement density of the cooling pins 3, and the sparse region 6 is formed by decreasing the arrangement density of the cooling pins 3. In other words, the dense region 5 is a region where the arrangement density of the cooling pins 3 arranged in the flow path R is relatively high. Furthermore, the sparse region 6 is a region where the arrangement density of the cooling pins 3 is relatively lower than that of the dense region 5.

[0047] In the cooler 1 of this embodiment, the flow path resistance between the dense region 5 and the sparse region 6 is adjusted by the arrangement density of the cooling pins 3. Therefore, the flow path resistance between the dense region 5 and the sparse region 6 can be adjusted with a simple structure.

[0048] It should be noted that the present invention is not limited to this embodiment. For example, as shown in FIG. 3 , instead of pin fins such as cooling pins 3, multiple straight fins 7 extending in the mainstream direction may be installed. In such a case, the dense regions 5 and sparse regions 6 can be formed by changing the spacing between the straight fins 7 in the flow path width direction. For example, by narrowing the spacing between the straight fins 7 in the flow path width direction, the dense regions 5 with high flow path resistance can be formed. Furthermore, by widening the spacing between the straight fins 7 in the flow path width direction, the sparse regions 6 with high flow path resistance can be formed.

[0049] It is also possible to use wave fins or three-dimensional lattice fins instead of the cooling pins 3 or straight fins 7. When using straight fins 7 or wave fins, it is advisable to provide a space between the sections 4 so that the heat of the cooling medium Y can be diffused.

[0050] Furthermore, except for the most downstream section 4a, the arrangement density of the cooling pins 3 in the dense region 5 (i.e., the flow path resistance of the dense region 5) may be gradually decreased from the upstream side to the downstream side in the mainstream direction. In other words, except for the most downstream section 4a, the arrangement density of the cooling pins 3 (fins) may be decreased the further downstream in the mainstream direction. Since the temperature of the cooling medium Y increases toward the downstream side in the mainstream direction, the flow rate of the cooling medium Y flowing directly below the heat-generating components X can be increased toward the downstream side to more uniformly distribute the temperatures of the multiple heat-generating components X.

[0051] Second Embodiment Next, a second embodiment of the present invention will be described with reference to Fig. 4. In the description of this embodiment, the description of the same parts as those in the first embodiment will be omitted or simplified.

[0052] 4 is a schematic, partially enlarged cross-sectional view of a semiconductor device 100 according to this embodiment. Note that FIG. 4 is a cross-sectional view including a semiconductor chip 12 different from the semiconductor chip 12 located furthest downstream in the main flow direction. The semiconductor device 100 according to this embodiment is, for example, a power conversion device that converts power between a battery and a motor. The semiconductor device 100 includes a cooler 1, a resin case 10, an insulating circuit board 11, a semiconductor chip 12 (semiconductor element), external terminals 13, a lead frame 14, lead wires 15, and a sealing material 16.

[0053] The cooler 1 is the cooler 1 of the first embodiment. The cooler 1 cools the semiconductor chip 12 and the like. The cooler 1 recovers heat transferred from the semiconductor chip 12 via the insulating circuit board 11 and the like by using a coolant. The cooler 1 functions as a base member that supports the insulating circuit board 11 and the like.

[0054] The resin case 10 is bonded to the cooler 1 via an adhesive layer 18. The resin case 10 holds a bus bar 17. The resin case 10 also has an opening in which the semiconductor chip 12 and the like are housed. As shown in Fig. 4, the bus bar 17 is held in a state in which the joint portion with the lead frame 14 is exposed toward the inside of the opening.

[0055] The insulating circuit board 11 has an insulating ceramic substrate and metal layers formed on both sides of the insulating ceramic substrate. The metal layer formed on the front side of the insulating ceramic substrate is electrically connected to the semiconductor chip 12 and forms part of the conductive circuit. The metal layer formed on the back side of the insulating ceramic substrate forms part of the heat transfer path that transfers heat from the semiconductor chip 12 and the like to the cooler 1.

[0056] The insulating ceramic substrate is, for example, aluminum oxide (Al ２ O ３ ), aluminum nitride (AlN), silicon ceramics (Si ３ Ni ４ The metal layer can be formed of, for example, copper (Cu) or aluminum (Al).

[0057] The semiconductor chip 12 is, for example, a chip on which an IGBT (insulated gate bipolar transistor) or a SiC-MOSFET is formed, and corresponds to the heat-generating component X (the object to be cooled) in the first embodiment. The semiconductor chip 12 is mounted on an insulating circuit board 11. In this embodiment, one semiconductor chip 12 is mounted on one insulating circuit board 11. Note that multiple semiconductor chips 12 may be mounted on one insulating circuit board 11. The semiconductor chip 12 may be formed using a silicon (Si) semiconductor. Alternatively, the semiconductor chip 12 may be formed using a wide-gap semiconductor such as a silicon carbide (SiC) semiconductor or a gallium nitride (GaN) semiconductor.

[0058] A plurality of pairs of semiconductor chips 12 and insulating circuit boards 11 are provided along the main flow direction of the cooler 1. The pairs of semiconductor chips 12 and insulating circuit boards 11 are arranged relative to the cooler 1 in the same manner as the heat-generating component X of the first embodiment, for example.

[0059] The external terminals 13 are held by the resin case 10. A plurality of external terminals 13 are provided, and each is connected to the semiconductor chip 12 via a lead wire 15. The semiconductor chip 12 is controlled from the outside via these external terminals 13.

[0060] The lead frame 14 is a plate-shaped conductive member that connects the semiconductor chip 12 and the bus bar 17. For example, two lead frames 14 are connected to one semiconductor chip 12. The lead frame 14 is a conductive member through which a larger current flows than the lead wires 15 through which a control signal flows. The lead frame 14 is connected to the semiconductor chip 12 and the bus bar 17. However, the lead frame 14 may also connect the insulating circuit board 11 and the bus bar 17.

[0061] The lead wires 15 are conductive members that connect the semiconductor chip 12 and the external terminals 13. That is, the semiconductor chip 12 and the external terminals 13 are electrically connected by so-called wire bonding.

[0062] The sealant 16 fills the interior of the opening of the resin case 10. The sealant 16 covers the insulating circuit board 11, the semiconductor chip 12, etc., and prevents the insulating circuit board 11, the semiconductor chip 12, etc. from coming into contact with air, etc. This sealant 16 can be made of, for example, silicone gel.

[0063] Furthermore, solder 20, which is a brazing material, is provided in various locations on the semiconductor device 100 of this embodiment. Specifically, as shown in FIG. 4 , solder 20 is provided at the joint between the lead frame 14 and the bus bar 17. That is, the lead frame 14 and the bus bar 17 are joined using the solder 20. Furthermore, solder 20 is provided at the joint between the lead frame 14 and the semiconductor chip 12. That is, the lead frame 14 and the semiconductor chip 12 are joined using the solder 20.

[0064] In addition, solder 20 is provided between semiconductor chip 12 and insulating circuit board 11. That is, semiconductor chip 12 and insulating circuit board 11 are joined using solder 20. In addition, solder 20 is provided between insulating circuit board 11 and cooler 1. That is, insulating circuit board 11 and cooler 1 are joined using solder 20.

[0065] 4, the lead wires 15 and the external terminals 13 are also soldered together, and the lead wires 15 and the semiconductor chip 12 are also soldered together.

[0066] The semiconductor device 100 of this embodiment includes the cooler 1 of the first embodiment. Therefore, the semiconductor device 100 of this embodiment can supply the cooling medium Y directly below the semiconductor chip 12 in the most downstream section 4a while suppressing a temperature rise in the cooling medium Y, thereby improving the cooling performance for the semiconductor chip 12 located downstream. Thermal interference, which is a phenomenon in which the temperature of the upstream semiconductor chip 12 affects the downstream heat-generating component X, can be suppressed.

[0067] Furthermore, the semiconductor device 100 of this embodiment can reduce the overall flow path resistance of the cooler 1, thereby reducing pressure loss. In this way, the semiconductor device 100 of this embodiment can reduce pressure loss and lower the temperature of the semiconductor chip 12, which has the highest temperature.

[0068] While the preferred embodiments of the present invention have been described above with reference to the accompanying drawings, it goes without saying that the present invention is not limited to the above-described embodiments. The shapes and combinations of the components shown in the above-described embodiments are merely examples, and various modifications can be made based on design requirements, etc., without departing from the spirit of the present invention.

[0069] While the preferred embodiments of the present invention have been described above with reference to the accompanying drawings, it goes without saying that the present invention is not limited to the above-described embodiments. The shapes and combinations of the components shown in the above-described embodiments are merely examples, and various modifications can be made based on design requirements, etc., without departing from the spirit of the present invention.

[0070] For example, in the above embodiment, a configuration has been described in which the flow path resistance of the dense region 5 and the sparse region 6 is adjusted by changing the fin arrangement density. However, the present invention is not limited to this. For example, the flow path resistance of the dense region 5 and the sparse region 6 may be adjusted by changing the shape of the fins. For example, it is possible to use cooling pins with a relatively large diameter as the fins in the dense region 5 and cooling pins with a relatively small diameter as the fins in the sparse region 6.

[0071] In the above embodiment, the cooling pins 3 have a circular shape when viewed from above. However, the present invention is not limited to this. For example, it is also possible to use cooling pins that are approximately circular when viewed from above and that narrow toward the downstream side as fins.

[0072] The above embodiment can also be described as follows, for example:

[0073] (Appendix 1) A cooler having a flow path through which a cooling medium flows and cooling a plurality of cooling objects, wherein the flow path is divided into a plurality of continuous compartments in a main flow direction of the cooling medium, and each compartment has a high flow path resistance region in which the flow path resistance is relatively high and a low flow path resistance region in which the flow path resistance is relatively lower than the high flow path resistance region, when viewed from an orthogonal direction that is perpendicular to the main flow direction, and in a specific compartment which cools a specific cooling object that is one of the cooling objects, when viewed from the orthogonal direction, the low flow path resistance region is arranged in a position overlapping with the specific cooling object, and the high flow path resistance region is arranged in a position not overlapping with the specific cooling object, and in at least one of the compartments located upstream of the specific compartment, when viewed from the orthogonal direction, the high flow path resistance region is arranged in a position overlapping with the cooling object, and the low flow path resistance region is arranged in a position not overlapping with the cooling object.

[0074] (Supplementary Note 2) The cooler according to Supplementary Note 1, wherein the specific section is located furthest downstream in the main flow direction among the plurality of sections.

[0075] (Appendix 3) A cooler according to appendix 1 or 2, characterized in that in the compartment located one compartment upstream of the specific compartment in the mainstream direction, the low flow resistance area is an area connected to the low flow resistance area of ​​the specific compartment from the upstream side in the mainstream direction.

[0076] (Supplementary Note 4) The cooler according to any one of Supplementary Notes 1 to 3, wherein the low flow resistance regions of the sections that are continuous in the main flow direction are connected to each other.

[0077] (Appendix 5) A cooler described in any one of Appendices 1 to 4, characterized in that in the sections that are continuous in the mainstream direction, the arrangement order of the high flow resistance region and the low flow resistance region in the section located upstream in the mainstream direction is reversed to the arrangement order of the high flow resistance region and the low flow resistance region in the section located downstream in the mainstream direction.

[0078] (Appendix 6) A cooler described in any one of Appendices 1 to 5, characterized in that the high flow path resistance region is a region where the arrangement density of fins arranged in the flow path is relatively high, and the low flow path resistance region is a region where the arrangement density of the fins is relatively lower than that of the high flow path resistance region.

[0079] (Supplementary Note 7) The cooler according to Supplementary Note 6, wherein the high flow resistance region, excluding the specific section, has a lower fin arrangement density as it moves downstream in the main flow direction.

[0080] (Supplementary Note 8) A semiconductor device comprising: the cooler according to any one of Supplementary Notes 1 to 7; and a semiconductor element that is the cooling target and is cooled by the cooler.

[0081] REFERENCE SIGNS LIST 1 Cooler 2 Housing 3 Cooling pin (fin) 4 Section 4a Most downstream section (specific section) 5 Dense area 6 Sparse area 7 Straight fin (fin) 12 Semiconductor chip (cooling target) 100 Semiconductor device R Flow path X Heat generating component (cooling target) Xa Most downstream heat generating component (specific cooling target) Y Cooling medium

Claims

1. A cooler having a flow path through which a cooling medium flows and cooling multiple cooling objects, wherein the flow path is divided into multiple continuous compartments in the main flow direction of the cooling medium, and each compartment has a high flow path resistance region in which the flow path resistance is relatively high and a low flow path resistance region in which the flow path resistance is relatively lower than the high flow path resistance region, when viewed from the orthogonal direction that is perpendicular to the main flow direction, and in a specific compartment which cools a specific cooling object that is one of the cooling objects, when viewed from the orthogonal direction, the low flow path resistance region is arranged in a position that overlaps with the specific cooling object, and the high flow path resistance region is arranged in a position that does not overlap with the specific cooling object, and in at least one of the compartments located upstream of the specific compartment, when viewed from the orthogonal direction, the high flow path resistance region is arranged in a position that overlaps with the cooling object, and the low flow path resistance region is arranged in a position that does not overlap with the cooling object.

2. A cooler according to claim 1, characterized in that the specific section is located furthest downstream in the main flow direction among the plurality of sections.

3. A cooler as described in claim 1 or 2, characterized in that in the compartment located one compartment upstream of the specific compartment in the mainstream direction, the low flow resistance area is the area connected to the low flow resistance area of ​​the specific compartment from the upstream side in the mainstream direction.

4. A cooler according to claim 1 or 2, characterized in that the low flow resistance regions of the sections that are consecutive in the main flow direction are connected to each other.

5. A cooler as described in claim 1 or 2, characterized in that in the sections that are continuous in the mainstream direction, the arrangement order of the high flow resistance region and the low flow resistance region in the section located upstream in the mainstream direction is reversed to the arrangement order of the high flow resistance region and the low flow resistance region in the section located downstream in the mainstream direction.

6. A cooler as claimed in claim 1 or 2, characterized in that the high flow resistance region is a region where the arrangement density of fins arranged in the flow path is relatively high, and the low flow resistance region is a region where the arrangement density of fins is relatively lower than that of the high flow resistance region.

7. A cooler according to claim 6, characterized in that the density of the fins in the high flow resistance region decreases as the region is positioned downstream in the main flow direction, excluding the specific section.

8. A semiconductor device comprising: the cooler according to claim 1 or 2; and a semiconductor element that is the object to be cooled by the cooler.

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