JP2006080211A - Semiconductor device - Google Patents

Abstract

A semiconductor device capable of improving the cooling capacity without using a pump having a large maximum discharge pressure is provided.
The pitch of fins 15b and 16b of cooling pipes 15 and 16 is made to differ according to the position in a direction substantially perpendicular to the cooling water flow direction. For example, the fin pitch immediately below and immediately above the IGBT element 11 is set to a relatively large P1, and the fin pitch of the other part B is set to a relatively small P2. Thereby, the cooling performance per pressure loss can be made high.
[Selection] Figure 1

Description

  The present invention relates to a semiconductor device, and more particularly to a semiconductor device characterized by a cooling pipe.

  As a conventional semiconductor device, for example, there is one disclosed in Patent Document 1. The semiconductor device disclosed in Patent Document 1 is provided with a plurality of fins in the cooling water channel in order to increase the cooling capacity of the semiconductor element.

  By the way, it is necessary to flow a large current to an inverter device used in a recent hybrid vehicle or the like. When a large current flows through the inverter device, heat generation of a semiconductor element such as an IGBT that constitutes the inverter device increases, so that it is necessary to further improve the cooling capability of the semiconductor element.

In order to improve the cooling capacity, for example, it is conceivable to increase the flow rate of the cooling water flowing in the cooling water channel. However, when the flow rate of the cooling water flowing through the cooling water channel is increased, the pressure loss in the cooling water channel increases. Therefore, it is necessary to use a pump capable of withstanding a large pressure loss, that is, a pump having a large maximum discharge pressure, as a pump for circulating cooling water.
JP-A-11-346480

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a semiconductor device capable of improving the cooling capacity without using a pump having a large maximum discharge pressure. .

  Therefore, the present inventor has intensively studied to solve this problem, and as a result of repeated trial and error, has found that the required cooling capacity varies depending on the position of the cooling water channel. Then, a semiconductor device that can increase the cooling efficiency by making the cooling capacity different depending on the position of the cooling water path of the semiconductor device without completing the same cooling capacity as in the conventional semiconductor device is completed. It came to do.

  That is, the semiconductor device of the present invention includes at least one semiconductor element, a substrate on which the semiconductor element is disposed on the first surface side, a coolant channel formed on the inner side, and a junction on the second surface side of the substrate. In the semiconductor device, comprising: a tubular portion that is formed; and a refrigerant circulation portion that includes a plurality of fins arranged along the refrigerant circulation direction on the inner side of the cylindrical portion and in the width direction of the substrate. The section is characterized in that the pressure loss per unit flow path varies depending on the distance from the semiconductor element. Here, the fin is a pleated member disposed in a direction substantially perpendicular to the substrate. And the refrigerant | coolant flow path inside the cylindrical part is divided | segmented by this fin. Furthermore, since the refrigerant circulation part has a plurality of fins on the inner side of the cylindrical part, a plurality of refrigerant flow paths are formed on the inner side of the cylindrical part.

  According to the semiconductor device of the present invention, since the refrigerant flow section has different pressure loss per unit flow path, the cooling capacity varies depending on the position of the divided refrigerant flow path of the refrigerant flow section. Since the pressure loss per unit flow path varies depending on the distance from the semiconductor element, the semiconductor device of the present invention has different cooling capabilities depending on the distance from the semiconductor element. Further, the semiconductor element becomes a heat source in the constituent members of the semiconductor device. That is, the cooling efficiency can be improved by varying the cooling capacity according to the distance from the heat source.

  As described above, the refrigerant circulation part of the semiconductor device of the present invention is configured such that the pressure loss per unit flow path varies depending on the distance from the semiconductor element. This refrigerant distribution part may be performed as follows, for example.

  For example, you may make it the pitch of the said fin of the said refrigerant | coolant distribution part differ according to the position of the direction substantially orthogonal to the said refrigerant | coolant distribution direction. Here, the pitch of fins refers to the interval between adjacent fins. That is, the widths of the plurality of refrigerant flow paths divided by the cylindrical portion and the fins are different by changing the pitch of the fins according to the position in the direction substantially orthogonal to the refrigerant flow direction. become. The width of the refrigerant channel is the width in the direction perpendicular to the fins in the refrigerant channel. Thus, by making the pitch of the fins different, the pressure loss per unit flow path is made different, and as a result, the cooling efficiency can be improved.

  Further, the pitch of the fins may be varied according to the distance from the semiconductor element. Here, as described above, the heat source of the semiconductor device is a semiconductor element. That is, the cooling capacity can be appropriately exhibited by changing the pitch of the fins according to the distance from the semiconductor element that is the heat generation source. That is, the fin pitch is adjusted so as to increase the cooling capacity at a position near the distance from the semiconductor element. On the other hand, the pitch of the fins is adjusted so as to reduce the cooling capacity at a position far from the semiconductor element. Thereby, cooling efficiency can be improved.

  Further, when the semiconductor device has a plurality of semiconductor elements, the following may be performed. That is, there may be a plurality of semiconductor elements, and the pitch of the fins may be varied according to the distance from each semiconductor element and the ratio of the amount of heat generated when each semiconductor element is driven. Thus, by setting the fin pitch in consideration of not only the distance from the semiconductor element but also the ratio of the amount of heat generated when the semiconductor element is driven, the cooling capacity required for each semiconductor element is appropriately exhibited. Can be made. For example, the highest cooling capacity is exhibited at a position where the distance from the semiconductor element having the largest ratio of the amount of heat generated when the semiconductor element is driven is close, and the position near the distance from the semiconductor element having the smallest ratio of the amount of heat generated is at the position. Cooling efficiency can be increased by exerting a relatively low cooling capacity. Further, at a position far from each semiconductor element, the cooling efficiency can be further lowered by lowering the cooling capacity as compared with a position at a short distance from the semiconductor element.

  The semiconductor device includes a plurality of semiconductor elements, and the pitch of the fins varies according to the distance from the semiconductor element having the largest ratio of the amount of heat generated when the semiconductor element is driven among the plurality of semiconductor elements. It may be. This is particularly effective when the amount of heat generated when driving a plurality of semiconductor elements differs greatly. That is, the cooling efficiency can be sufficiently increased by making the pitch of the fins different according to the distance from only the semiconductor element having the largest ratio of the amount of heat generated during driving that requires a high cooling capacity. Further, the pitch of the fins can be varied according to the distance from only a specific semiconductor element among the plurality of semiconductor elements in consideration of the distance from all the semiconductor elements and the ratio of the heat generation amount. As compared with the case where the pitches of these are made different, the refrigerant circulation part can be easily designed. That is, it is possible to facilitate the design and manufacture of the refrigerant distribution part.

  As described above, when the pitch of the fins is made different according to the distance from the semiconductor element, the pitch of the fins may be configured as follows. First, the pitch of the fins at a position where the distance from the semiconductor element is short is larger than the pitch of the fins at a position where the distance is far. Where the fin pitch is large, the cooling capacity is higher than when the fin pitch is small. Thus, the cooling capacity can be reliably increased by increasing the pitch of the fins at positions close to the semiconductor element.

  Second, the pitch of the fins may be reduced as the distance from the semiconductor element increases. For example, the fin pitch is continuously reduced as the distance from the semiconductor element increases. Here, increasing the pitch of the fins at a position close to the semiconductor element can surely increase the cooling capacity as described above. Furthermore, by making the pitch of the fins continuously different according to the distance from the semiconductor element, it is possible to suppress the occurrence of eddy currents in the vicinity of the inlet / outlet of the refrigerant circulation portion. As a result, it is possible to reliably cause the refrigerant to flow through the refrigerant flow path, and thus it is possible to reliably exhibit the cooling capacity.

  In addition, as described above, when the fin pitch is made different according to the ratio of the heat generation amount generated when the semiconductor element is driven, the fins at the positions where the distance from the semiconductor element having the large heat generation ratio is short are close. The pitch may be larger than the pitch of the fins at a position where the distance from the semiconductor element having a small ratio of the heat generation amount is short. As described above, a high cooling capacity can be exhibited where the fin pitch is large. Therefore, by increasing the pitch of the fins at a position close to the semiconductor element having a large ratio of the amount of heat generated during driving, it is possible to demonstrate the cooling capacity corresponding to the cooling capacity required for each semiconductor element. it can.

  In the above description, the fin pitch is varied depending on the distance from the semiconductor element or the ratio of the amount of heat generated during driving, but the fin pitch depends on the temperature distribution of the substrate due to the heat generated by the semiconductor element. It may be made different depending on the case. The refrigerant circulation part is joined to the opposite side of the surface of the substrate on which the semiconductor element is disposed. That is, the heat from the semiconductor element is cooled by the cooling flow part through the substrate. Therefore, the cooling capacity can be appropriately exhibited by changing the fin pitch according to the temperature distribution of the substrate due to the heat generation of the semiconductor element. That is, the cooling efficiency near the high temperature is increased in the temperature distribution of the substrate due to the heat generation of the semiconductor element, and the cooling capacity near the low temperature is decreased in the temperature distribution of the substrate due to the heat generation of the semiconductor element. Can be increased.

  For example, the pitch of the fins near the maximum temperature in the temperature distribution of the substrate is made larger than the pitch of the fins near the minimum temperature in the temperature distribution of the substrate. By increasing the pitch of the fins in the vicinity of the maximum temperature in the temperature distribution of the substrate due to the heat generated by the semiconductor element, the cooling capacity can be reliably increased. On the other hand, the cooling capacity is lowered by decreasing the fin pitch near the lowest temperature in the temperature distribution of the substrate.

  Moreover, you may make it join the both after forming the said cylindrical part and several said fins which comprise a refrigerant | coolant distribution | circulation part to a different body, respectively. Moreover, you may integrally mold the whole cylindrical part and all the some fins. Alternatively, a part of the cylindrical part and the plurality of fins may be integrally formed and joined to the remaining cylindrical part. A part of the case constituting the outer frame of the semiconductor device can be used as the remaining cylindrical portion. In addition, manufacture of the whole refrigerant | coolant distribution part becomes easy by integrally forming at least one part of a cylindrical part and a fin.

  The semiconductor device of the present invention may have a so-called single-sided cooling structure or a double-sided cooling structure. In a semiconductor device having a double-sided cooling structure, the substrate is disposed on both sides of the semiconductor element, and the coolant circulation part is bonded to the second surface side of each of the substrates. By employing a double-sided cooling structure, the cooling efficiency can be further increased.

  Here, the semiconductor device of the present invention is compared with the conventional semiconductor device. As described above, the pitch of the fins of the cooling pipe of the conventional semiconductor device is uniform. That is, the same cooling capacity is exhibited regardless of the position in the direction substantially orthogonal to the refrigerant flow direction. In contrast, according to the present invention, the pitch of the fins in the cooling flow section is made different depending on the position in the direction substantially perpendicular to the refrigerant flow direction. Where the fin pitch is large, the flow rate of the refrigerant flowing through the refrigerant flow path increases due to the decrease in resistance. That is, a high cooling capacity is exhibited where the fin pitch is large. On the other hand, where the fin pitch is small, the flow rate of the refrigerant flowing through the refrigerant flow path becomes slow due to the increase in resistance. That is, the cooling capacity is low where the fin pitch is small.

  In other words, by varying the fin pitch, the cooling capacity varies depending on the position of the refrigerant circulation portion. And the pitch of the fin of the position where high cooling capacity is required is enlarged, and the pitch of the fin of the position where cooling capacity is not so required is reduced. As described above, the semiconductor device of the present invention capable of improving the cooling efficiency can improve the cooling capacity as compared with the conventional semiconductor device having the same pressure loss.

  Next, the case where the semiconductor device of the present invention and the conventional semiconductor device exhibit equivalent cooling capability will be compared. Here, in order for the conventional semiconductor device to increase the cooling capacity, it is necessary to increase the flow rate of the refrigerant flowing through the entire refrigerant circulation part by increasing the flow rate of the refrigerant flowing through the refrigerant circulation part. On the other hand, since the semiconductor device of the present invention has different cooling capacities depending on the position, it is possible to create a specific part that increases the flow rate of the refrigerant without increasing the flow rate of the refrigerant flowing through the entire refrigerant circulation part. . That is, in order for both semiconductor devices to exhibit the same cooling capacity, the flow rate of the refrigerant flowing through the refrigerant circulation portion of the semiconductor device of the present invention is small, and the flow rate of the refrigerant flowing through the refrigerant circulation portion of the conventional semiconductor device is large. Become.

  This is because the conventional semiconductor device has a large pressure loss in the entire refrigerant circulation part, whereas the semiconductor device of the present invention has a large pressure loss in the portion where the fin pitch is large, but the pressure loss in the portion where the fin pitch is small. Becomes smaller. That is, the semiconductor device of the present invention can reduce pressure loss as a whole. And since the semiconductor device of this invention can reduce a pressure loss, the thing with the low maximum discharge pressure of the pump which circulates a refrigerant | coolant can be used. Since a pump having a low maximum discharge pressure can be used, the cost of the pump can be reduced, and the entire apparatus can be downsized as the pump is downsized.

  As described above, the semiconductor device of the present invention can exhibit a much higher cooling capacity than the conventional semiconductor device in the case of the equivalent pressure loss. In addition, the semiconductor device of the present invention can reduce pressure loss as compared with a conventional semiconductor device when the same cooling capacity is exhibited. In the above description, either one of the pressure loss and the cooling capacity is compared as equivalent, but the semiconductor device of the present invention can also increase the cooling capacity while reducing the pressure loss as compared with the conventional semiconductor device.

  Next, an Example is given and this invention is demonstrated more concretely. By providing a plurality of semiconductor devices according to the present embodiment, for example, an inverter device, a converter device, or the like is configured. In the following embodiments, a semiconductor device using one IGBT element and one diode element as semiconductor elements will be described as an example.

(1) First Example A semiconductor device 1 according to a first example will be described with reference to FIG. FIG. 1 is a cross-sectional view of a semiconductor device 1 according to the first embodiment. As shown in FIG. 1, the semiconductor device 1 of the first embodiment includes an IGBT element 11 and a diode element 12, which are semiconductor elements, a lower electrode (substrate) 13, an upper electrode (substrate) 14, and a lower cooling. A pipe (refrigerant circulation part) 15, an upper cooling pipe (refrigerant circulation part) 16, an IGBT spacer 17, and a diode spacer 18 are provided. The semiconductor device 1 of the first embodiment has a so-called double-sided cooling structure.

  The IGBT element 11 has an upper surface in FIG. 1 on the emitter side and a lower surface on the collector side. Although not shown, the gate of the IGBT element 11 is output from a part of the upper surface of FIG. The diode element 12 has a top surface in FIG. 1 on the cathode side and a bottom surface on the anode side.

  The lower electrode 13 is made of, for example, a copper metal plate. The IGBT element 11 and the diode element 12 are placed on the upper surface of the lower electrode 13. Specifically, the IGBT element 11 is placed at substantially the center of the lower electrode 13 in FIG. 1, and the diode element 12 is placed on the left side of the lower electrode 13 in FIG. Furthermore, the upper surface of the lower electrode 13 and the IGBT element 11 and the diode element 12 are electrically connected via a conductive adhesive such as solder. That is, the lower electrode 13 constitutes a collector side electrode (or an anode side electrode).

  Similar to the lower electrode 13, the upper electrode 14 is made of a copper metal plate. The upper electrode 14 is disposed so as to face the lower electrode 13 substantially in parallel with the IGBT element 11 and the diode element 12 sandwiched therebetween. Specifically, the IGBT element 11 is disposed at the substantially center of the upper electrode 14 in FIG. 1, and the diode element 12 is disposed on the left side of the upper electrode 14 in FIG. 1. However, an IGBT spacer 17 and a diode spacer 18 are disposed between the lower surface of the upper electrode 14 and the IGBT element 11 and the diode element 12, respectively. Here, the IGBT spacer 17 and the diode spacer 18 are made of a copper metal plate, and the height direction is adjusted, and the conductivity and thermal conductivity from the emitter of the IGBT element 11 and the diode element 12 to the upper electrode 14 are adjusted. It is possible to ensure. Further, between the lower surface of the upper electrode 14 and the spacers 17 and 18, between the IGBT spacer 17 and the IGBT element 11, and between the diode spacer 18 and the diode element 12, a conductive material such as solder is provided. Electrical connection is made through a conductive adhesive. That is, the upper electrode 14 constitutes an emitter side electrode (or a cathode side electrode).

  The lower cooling pipe 15 and the upper cooling pipe 16 form a cooling water channel (refrigerant channel) on the inner side. The widths of the lower cooling pipe 15 and the upper cooling pipe 16 are substantially equal to the widths of the lower electrode 13 and the upper electrode 14. The upper surface of the lower cooling tube 15 is bonded to the lower surface of the lower electrode 13, and the lower surface of the upper cooling tube 16 is bonded to the upper surface of the upper electrode 14. That is, the lower cooling pipe 15 and the upper cooling pipe 16 are arranged to face each other and sandwich the IGBT element 11, the diode element 12, the lower electrode 13, and the upper electrode 14.

  The configurations of the lower cooling pipe 15 and the upper cooling pipe 16 (hereinafter referred to as “cooling pipes 15 and 16”) will be described in more detail. The cooling pipes 15 and 16 are comprised from the cylindrical parts 15a and 16a which formed the cooling water flow path in the inner side, and the several fin 15b and 16b arrange | positioned at the inner side of the cylindrical parts 15a and 16a. The cylindrical portions 15a and 16a are formed in a flat cylindrical shape made of an aluminum material. A plurality of fins 15b and 16b are arranged in the width direction in FIG. 1 of the lower electrode 13 and the upper electrode 14 along the cooling water flow direction. That is, as shown in FIG. 1, the fins 15b and 16b are formed in a thin plate shape and are arranged in a direction perpendicular to the lower electrode 13 and the upper electrode 14, and the upper and lower ends are the inner circumferences of the cylindrical portions 15a and 16a. Bonded to the surface. That is, the cooling water flow paths inside the cylindrical portions 15a and 16a are divided into a plurality of pieces in the width direction of FIG. 1 by the fins 15b and 16b. For convenience of manufacturing, the plurality of fins 15b of the lower cooling pipe 15 or the plurality of fins 16b of the upper cooling pipe 16 are integrally formed.

  And the pitch (henceforth "fin pitch") of the fins 15b and 16b, ie, the space | interval of the adjacent fins 15b and 16b, is made to differ according to the position of the direction substantially orthogonal to a coolant flow direction. Specifically, the A portion of the cooling pipes 15 and 16 has a fin pitch P1, and the B portion has a fin pitch P2. Here, the fin pitch P1 is larger than the fin pitch P2. That is, the vicinity of the center of the cooling pipes 15 and 16 in FIG. 1 has a relatively large fin pitch P1, and both end sides of the cooling pipes 15 and 16 have a relatively small fin pitch P2. Here, the vicinity of the center of the cooling pipes 15 and 16 is a position where the IGBT element 11 is sandwiched. That is, the fin pitch P1 directly below or near the top of the IGBT element 11 is set to a larger fin pitch than the fin pitch P2 at other positions. In other words, the fin pitch at a position where the distance from the IGBT element 11 having the largest ratio of the amount of heat generated during driving is close is set to be larger than the fin pitch at a position where the distance from the IGBT element 11 is far.

  When cooling water flows through the cooling pipes 15 and 16 having the above-described configuration, the operation is as follows. The A portion of the cooling pipes 15 and 16 having the fin pitch P1 is larger than the fin pitch P2 of the B portion and has a smaller resistance, so that the flow rate of the cooling water increases. On the other hand, in the B portion of the cooling pipes 15 and 16 having the fin pitch P2, the resistance increases compared to the A portion, so that the flow rate of the cooling water is reduced. Here, the cooling capacity increases as the flow rate of the cooling water increases. Therefore, the cooling capacity in the A portion of the cooling pipes 15 and 16 is higher than that in the B portion. Thus, the pressure loss per unit flow path is made different by changing the fin pitch depending on the positions of the cooling pipes 15 and 16. That is, the cooling capacity varies depending on the positions of the cooling pipes 15 and 16.

  By the way, what generates heat in the semiconductor device 1 is the semiconductor element of the IGBT element 11 and the diode element 12. However, the ratio of the amount of heat generated when the diode element 12 is driven is generally smaller than the ratio of the amount of heat generated when the IGBT element 11 is driven. Therefore, the cooling pipes 15 and 16 of the semiconductor device 1 of the first embodiment increase the fin pitch only in the vicinity of the IGBT element 11 to improve the cooling capacity in the vicinity of the IGBT element 11. And the cooling capacity of other parts is made low. In this way, the cooling efficiency is enhanced by making the cooling capacity different depending on the vicinity of the IGBT element 11 having the largest heat generation amount generated during driving and other positions among the heat sources.

(2) Second Embodiment A semiconductor device 2 according to a second embodiment will be described with reference to FIG. FIG. 2 is a cross-sectional view of the semiconductor device 2 of the second embodiment. Here, the same components as those of the semiconductor device 1 of the first embodiment are denoted by the same reference numerals, and description thereof is omitted. As shown in FIG. 2, the semiconductor device 2 of the second embodiment includes an IGBT element 11 and a diode element 12 which are semiconductor elements, a lower electrode (substrate) 13, an upper electrode (substrate) 14, and lower cooling. A pipe (refrigerant circulation part) 25, an upper cooling pipe (refrigerant circulation part) 26, an IGBT spacer 17, and a diode spacer 18 are provided. That is, the semiconductor device 2 of the second embodiment also has a double-sided cooling structure, like the semiconductor device 1 of the first embodiment. The semiconductor device 2 of the second embodiment differs from the semiconductor device 1 of the first embodiment only in the lower cooling pipe 25 and the upper cooling pipe 26. Specifically, only the fins 25b and 26b of the lower cooling pipe 25 and the upper cooling pipe 26 are different. Hereinafter, the lower cooling pipe 25 and the upper cooling pipe 26 will be described in detail.

  The configurations of the lower cooling pipe 25 and the upper cooling pipe 26 (hereinafter referred to as “cooling pipes 25 and 26”) will be described in detail. The cooling pipes 25 and 26 are configured by cylindrical portions 15a and 16a in which cooling water flow paths are formed on the inner side, and a plurality of fins 25b and 26b arranged on the inner side of the cylindrical portions 15a and 16a. The cylindrical portions 15a and 16a are the same as the cylindrical portions 15a and 16a of the cooling pipes 15 and 16 constituting the semiconductor device 1 of the first embodiment described above. A plurality of fins 25b and 26b are arranged in the width direction in FIG. 2 of the lower electrode 13 and the upper electrode 14 along the cooling water flow direction. That is, as shown in FIG. 2, the fins 25b and 26b are formed in a thin plate shape and are arranged in a direction perpendicular to the lower electrode 13 and the upper electrode 14, and the upper and lower ends are the inner circumferences of the cylindrical portions 15a and 16a. Bonded to the surface. That is, the cooling water flow paths inside the cylindrical portions 15a and 16a are divided into a plurality in the width direction of FIG. 2 by the fins 25b and 26b. For convenience of manufacturing, the plurality of fins 25b of the lower cooling pipe 25 or the plurality of fins 26b of the upper cooling pipe 26 are integrally formed.

  And the pitch (henceforth "fin pitch") of the fins 25b and 26b, ie, the space | interval of the adjacent fins 25b and 26b, is made to differ according to the position of the direction substantially orthogonal to a coolant flow direction. Specifically, the C portion of the cooling pipes 25 and 26 has a fin pitch P1, the D portion has a fin pitch P1 ', and the E portion has a fin pitch P2. Here, the fin pitch P1 is larger than the fin pitch P1 ', and the fin pitch P1' is larger than the fin pitch P2. That is, the vicinity of the center of the cooling pipes 25 and 26 in FIG. 2 and the left side thereof have a relatively large fin pitch P1, and the right end sides of the cooling pipes 25 and 26 have a relatively small fin pitch P2. Further, the boundary portion between the fin pitch P1 portion and the fin pitch P2 portion is an intermediate fin pitch P1 '. Here, the vicinity of the center of the cooling pipes 25 and 26 and the left side thereof are positions where the IGBT element 11 and the diode element 12 are sandwiched. That is, the fin pitch P1 directly below or near the top of the IGBT element 11 and the diode element 12 is set to a larger fin pitch than the other fin pitch P2. In other words, the fin pitch at a position where the distance from the IGBT element 11 and the diode element, which are heat sources, is close is set to be larger than the fin pitch at a position where the distance from the IGBT element 11 and the diode element 12 is far.

  When cooling water flows through the cooling pipes 25 and 26 having the above-described configuration, the operation is as follows. The portion C of the cooling pipes 25 and 26 having the fin pitch P1 is larger than the fin pitch P2 of the E portion and has a smaller resistance, so that the flow rate of the cooling water is increased. On the other hand, in the E portion of the cooling pipes 25 and 26 having the fin pitch P2, the resistance increases compared to the C portion, so that the flow rate of the cooling water is reduced. Here, the cooling capacity increases as the flow rate of the cooling water increases. Therefore, the cooling capacity in the C part of the cooling pipes 25 and 26 is higher than the cooling capacity in the E part. Thus, the pressure loss per unit flow path is made different by changing the fin pitch depending on the positions of the cooling pipes 25 and 26. That is, the cooling capacity varies depending on the positions of the cooling pipes 25 and 26.

  By the way, as described above, the semiconductor device 2 that generates heat is the semiconductor element of the IGBT element 11 and the diode element 12. Therefore, the cooling pipes 25 and 26 of the semiconductor device 2 according to the second embodiment increase the fin pitch in the vicinity of the IGBT element 11 and the diode element 12 to improve the cooling capability in the vicinity of the IGBT element 11. And the fin pitch of parts other than IGBT element 11 and the diode element 12 vicinity is made small, and cooling capacity is made low. As described above, the cooling efficiency is enhanced by making the cooling capacity different depending on the vicinity of the IGBT element 11 and the diode element 12 which are heat generation sources and other positions.

(3) Third Embodiment A semiconductor device 3 according to a third embodiment will be described with reference to FIG. FIG. 3 is a cross-sectional view of the semiconductor device 3 of the third embodiment. Here, the same components as those of the semiconductor device 1 of the first embodiment are denoted by the same reference numerals, and description thereof is omitted. As shown in FIG. 3, the semiconductor device 3 of the third embodiment includes an IGBT element 11 and a diode element 12 that are semiconductor elements, an electrode (substrate) 13, and a cooling pipe 35. That is, the semiconductor device 3 of the third embodiment has a so-called single-side cooling structure. Of the configuration of the semiconductor device 3 of the third embodiment, the configuration different from the semiconductor device 1 of the first embodiment is substantially only the cooling pipe 35. Specifically, only the fins 35b of the cooling pipe 35 are different. Hereinafter, the cooling pipe 35 will be described in detail.

  The cooling pipe 35 forms a cooling water channel (refrigerant channel) on the inner side. The width of the cooling pipe 35 is substantially equal to the width of the electrode 13. The upper surface of the cooling pipe 35 is joined to the lower surface (second surface) of the electrode 13.

  The configuration of the cooling pipe 35 will be described in more detail. The cooling pipe 35 is comprised from the cylindrical part 15a which formed the cooling water flow path in the inner side, and the several fin 35b arrange | positioned at the inner side of the cylindrical part 15a. The cylindrical portion 15a is the same as the cylindrical portion 15a of the lower cooling pipe 15 constituting the semiconductor device 1 of the first embodiment described above. A plurality of fins 35b are arranged in the width direction in FIG. That is, as shown in FIG. 3, the fins 35b are formed in a thin plate shape, are arranged in the vertical direction with respect to the electrode 13, and the upper and lower ends are joined to the inner peripheral surface of the cylindrical portion 15a. That is, the cooling water flow path inside the cylindrical portion 15a is divided into a plurality of pieces in the width direction of FIG. 3 by the fins 35b. For convenience of manufacturing, the plurality of fins 35b of the cooling pipe 35 are integrally formed.

  The pitch of the fins 35b (hereinafter referred to as “fin pitch”), that is, the interval between the adjacent fins 35b is made different depending on the position in the direction substantially orthogonal to the coolant flow direction. Specifically, the fin pitch PN of the F portion of the cooling pipe 35 is gradually decreased from the vicinity of the center of the cooling pipe 35 toward both ends. Specifically, when the fin pitch PN near the center of the cooling pipe 35 is 1, the adjacent fin pitch PN is 0.9, and the adjacent fin pitch PN is 0.81. That is, the fin pitch PN is set to be 0.9 times from the vicinity of the center toward both ends. Further, the fin pitch of the G portion of the cooling pipe 35 is P2. Here, all the fin pitches PN are set to be larger than the fin pitch P2. In other words, the fin pitch PN near the IGBT element 11 is set to be larger than the fin pitch P2 at other positions.

  When cooling water is caused to flow through the cooling pipe 35 having the above-described configuration, the following occurs. The F portion of the cooling pipe 35, which is the fin pitch PN, is larger than the fin pitch P2 of the G portion, and the resistance is reduced, so that the flow rate of the cooling water is increased. On the other hand, in the G portion of the cooling pipe 35 having the fin pitch P2, the resistance is larger than that in the F portion, so that the flow rate of the cooling water is reduced. Here, as described above, the cooling capacity increases as the flow rate of the cooling water increases. Therefore, the cooling capacity in the F part of the cooling pipe 35 is higher than the cooling capacity in the G part. Thus, the pressure loss per unit flow path is made different by changing the fin pitch depending on the position of the cooling pipe 35. That is, the cooling capacity varies depending on the position of the cooling pipe 35.

  By the way, as described in the first embodiment, the semiconductor device 2 that generates heat is the semiconductor element of the IGBT element 11 and the diode element 12. However, the ratio of the amount of heat generated when the diode element 12 is driven is generally smaller than the ratio of the amount of heat generated when the IGBT element 11 is driven. Therefore, the cooling pipe 35 of the semiconductor device 3 according to the third embodiment increases the fin pitch only in the vicinity of the IGBT element 11 to improve the cooling capacity in the vicinity of the IGBT element 11. And the fin pitch of other parts is made small and cooling capacity is made low. As described above, the cooling efficiency is improved by making the cooling capacity different depending on the vicinity of the IGBT element 11 where the ratio of the heat generation amount generated during driving, among other heat sources, is the maximum and other positions.

  Further, the fin pitch PN of the F portion of the cooling pipe 35 is gradually decreased from the vicinity of the center toward both ends. That is, the difference in fin pitch at the boundary position between the F portion and the G portion of the cooling pipe 35 is reduced. As a result, it is possible to suppress, for example, the generation of vortex near the boundary between the F portion and the G portion of the cooling pipe 35. Therefore, it is possible to ensure that the cooling water flows through the cooling water channel even in the vicinity of the boundary between the F portion and the G portion of the cooling pipe 35. That is, the cooling capacity can be reliably ensured even in the vicinity of the boundary between the F portion and the G portion of the cooling pipe 35.

(4) Other Embodiments (4.1) Modified Embodiments of the First and Second Embodiments The cooling pipes 15, 16, 25, and 26 of the semiconductor devices 1 and 2 of the first and second embodiments. These fin pitches are two or three types of relatively large fin pitch P1 and relatively small fin pitch P2, but are not limited thereto. The fin pitch can be three or more or four or more, and can be gradually changed as in the third embodiment.

  For example, with respect to the cooling pipes 15 and 16 of the semiconductor device 1 of the first embodiment, the fin pitch may be reduced in several steps as the distance from the position immediately below the IGBT element 11 increases. Further, for example, the fin pitch may be gradually reduced so as to be 0.9 times the adjacent fin pitch immediately below the IGBT element 11. With respect to the cooling pipes 25 and 26 of the semiconductor device 2 of the second embodiment, the fin pitch may be reduced in several steps as the distance from the middle of the IGBT element 11 and the diode element 12 increases. Further, for example, the fin pitch may be gradually reduced as the distance from the middle of the IGBT element 11 and the diode element 12 increases. Furthermore, the fin pitch may be decreased in several steps or gradually as the distance from the position slightly closer to the IGBT element 11 than the intermediate position between the IGBT element 11 and the diode element 12 is increased. Here, the position slightly closer to the IGBT element 11 than the intermediate position between the IGBT element 11 and the diode element 12 is used as a reference because the ratio of the amount of heat generated when the IGBT element 11 is driven is generated when the diode element 12 is driven. This is because the IGBT element 11 requires a higher cooling capacity than the diode element 12 because it is larger than the ratio of the amount of heat generated.

  Further, like the cooling pipe 35 of the semiconductor device 3 of the third embodiment, the fin pitch in a predetermined range is relatively large and gradually changes, and the other portions are relatively small constant fin pitch. It is good. That is, the cooling pipe 35 of the semiconductor device 3 of the third embodiment can be applied almost as it is to the cooling pipes 15 and 16 of the semiconductor device 1 of the first embodiment, and the same effect can be obtained. Of course, the present invention can also be applied with appropriate modifications to the cooling pipes 25 and 26 of the semiconductor device 2 of the second embodiment.

  In the cooling pipes 25 and 26 of the semiconductor device 2 of the second embodiment, the fin pitch in the vicinity of the IGBT element 11 and the diode element 12 is larger than the fin pitch at other positions. In addition to this, the fin pitch near the IGBT element 11 and the diode element 12 may be different in consideration of the ratio of the amount of heat generated when the IGBT element 11 and the diode element 12 are driven. That is, the fin pitch in the vicinity of the IGBT element 11 having the largest ratio of the heat generation amount generated during driving among the semiconductor elements is compared with the fin pitch in the vicinity of the diode element 12 having the smallest ratio of heat generation amount generated in the semiconductor element. And a large fin pitch. However, the fin pitch near the diode element 12 is set larger than the fin pitch at positions other than the IGBT element 11 and the diode element 12. Thus, an appropriate fin pitch is set according to the ratio of the amount of heat generated during driving.

(4.2) Modification of Third Embodiment The fin pitch PN of the F portion of the cooling pipe 35 of the semiconductor device 3 of the third embodiment is gradually reduced as the distance from the center of the cooling pipe 35 increases. However, it is not limited to this. For example, the fin pitch PN near the center of the IGBT element 11 may be maximized and gradually decreased as the distance from the position increases.

  Further, in the cooling pipe 35 of the semiconductor device 3 of the third embodiment, the F portion has a relatively large and gradually changing fin pitch PN, and the G portion has a relatively small constant fin pitch P2. It is not limited to. For example, it is good also as a fin pitch which changes gradually the whole cooling pipe 35, without dividing | segmenting into F part and G part. Specifically, for example, a fin pitch that gradually decreases as the distance from the vicinity immediately below the IGBT element 11 is set.

  Further, the fin pitch of the cooling pipe 35 of the semiconductor device 3 of the third embodiment is set to a relatively small fin pitch PN and a relatively small fin pitch P2, but is not limited thereto. is not. For example, the cooling pipes 15 and 16 of the semiconductor device 1 of the first embodiment or a cooling pipe of a modification thereof can be applied to the cooling pipe 35 of the semiconductor device 3 of the third embodiment.

(4.3) Other Modifications In the first to third embodiments and the modification thereof, the fin pitch is varied according to the distance from the semiconductor element, but is not limited thereto. For example, the fin pitch may be varied according to the temperature distribution of the electrodes 13 and 14 accompanying the heat generation of the semiconductor element. That is, the fin pitch near the high temperature in the temperature distribution of the electrodes 13 and 14 may be made larger than the fin pitch near the low temperature in the temperature distribution. In addition, according to the said temperature distribution, a fin pitch may be changed smoothly and a fin pitch may be changed in several steps. In addition, it is preferable to employ | adopt the temperature distribution of the part joined to a cooling pipe among the electrodes 13 and 14 as the temperature distribution of the said electrodes 13 and 14. FIG.

(4.4) Forming Form of Cooling Tube In the first to third embodiments and the modified embodiments thereof, the cooling pipe is formed by separately forming the cylindrical portion and the fin, and then joining them. It is molded as follows. However, the present invention is not limited to this, and other molding methods can be adopted. For example, the cylindrical portion and the fin can be integrally formed.

  Alternatively, only a part of the cylindrical part and the fins are integrally formed, and the remaining part of the cylindrical part can be joined. In this case, for example, a part of the resin case constituting the outer frame of the semiconductor device can be used as the remaining portion of the cylindrical portion.

(5) Comparison of cooling performance between the semiconductor device of the present embodiment and the conventional semiconductor device (5.1) Configuration of the conventional semiconductor devices 4 and 5 Next, the semiconductor device 1 of the first embodiment and the second embodiment will be described. The cooling performance of the semiconductor device 2 and the conventional semiconductor device will be compared. The semiconductor device 1 of the first embodiment and the semiconductor device 2 of the second embodiment are as described above. Here, a cross-sectional view of the conventional first semiconductor device 4 is shown in FIG. 4, and a cross-sectional view of the conventional second semiconductor device 5 is shown in FIG. The conventional semiconductor devices 4 and 5 are different from the semiconductor devices 1 and 2 of the first and second embodiments only in the fins of the cooling pipe. Only the fins of the cooling pipes of the conventional semiconductor devices 4 and 5 will be described below.

  The fin pitches of the cooling pipes of the conventional first semiconductor device 4 are uniform. This fin pitch is set to the same fin pitch P2 as the fin pitch P2 of the semiconductor devices 1 and 2 of the first and second embodiments. Note that, in the plurality of fins of the conventional first semiconductor device 4, the upper end side and the lower end side of adjacent fins are alternately formed integrally.

  The cross-sectional shape of the plurality of fins of the cooling pipe of the conventional second semiconductor device 5 is integrally formed so that H-shapes and O-shapes are alternately arranged. The fin pitch is uniform and is the same fin pitch P2 as the fin pitch P2 of the semiconductor devices 1 and 2 of the first and second embodiments.

(5.2) Analysis conditions Next, analysis conditions will be described. First, the shape values of the semiconductor devices 1 and 2 of the first and second embodiments and the conventional first and second semiconductor devices 4 and 5 are as follows. The overall shape of the semiconductor device is such that the width in the left-right direction (cooling water distribution vertical width) in FIGS. 1 to 5 is 49 mm, the height in FIGS. 1 to 5 is 19 mm, and the width in the depth direction (cooling water distribution direction width). Is 23 mm. The cooling water flow direction width of the IGBT element 11 is 9.4 mm, and the cooling water flow direction width of the diode element 12 is 5.9 mm. The height of the lower electrode 13 and the upper electrode 14 is 3 mm. The height of the cooling pipes 15, 16, 25, 26, etc. is 5 mm. And the plate | board thickness of the cylindrical parts 15a and 16a of a cooling pipe is 1.5 mm, and plate | board thicknesses, such as fin 15b and 16b, are 0.5 mm. The fin pitch is 2.5 mm for P1, 1.5 mm for P1 ′, and 1.5 mm for P2.

  The flow rate of the cooling water supplied to the cooling pipes of the semiconductor devices 1 to 5 having such a shape is set to a constant value of 1.33 L / min. Furthermore, the initial temperature of the cooling water to be supplied is 65 ° C.

(5.3) Analysis Results Table 1 shows the results of analysis based on the above analysis conditions. Furthermore, the graph about the cooling performance per pressure loss among analysis results is shown in FIG.

表１に示すように、圧損ΔＰは、第１実施例及び第２実施例の半導体装置１、２が非常に小さくなっている。ここで、圧損ΔＰは、フィンの形状、冷却管を流れる冷却水の流速、冷却水の粘性などから算出することができる。なお、第１実施例及び第２実施例の圧損ΔＰが非常に小さくなっている要因の一つは以下のことが考えられる。第１実施例及び第２実施例の半導体装置１、２の冷却管のフィンピッチが相対的に大きなＰ１の部分においては圧損が大きくなる方向に作用するが、フィンピッチが相対的に小さなＰ２の部分においては圧損が小さくなる方向に作用する。このように圧損を位置によって分散することにより、結果として全体として圧損を低減することができると考えられる。

As shown in Table 1, the pressure loss ΔP is very small in the semiconductor devices 1 and 2 of the first and second embodiments. Here, the pressure loss ΔP can be calculated from the shape of the fin, the flow rate of the cooling water flowing through the cooling pipe, the viscosity of the cooling water, and the like. Note that one of the factors that cause the pressure loss ΔP in the first and second embodiments to be very small is as follows. In the portion of P1 where the fin pitch of the cooling pipes of the semiconductor devices 1 and 2 of the first embodiment and the second embodiment is relatively large, the pressure loss increases, but the fin pitch of P2 is relatively small. In the portion, the pressure loss is reduced. As described above, it is considered that the pressure loss can be reduced as a whole by dispersing the pressure loss depending on the position.

  The pressure loss ΔP / L per unit distance is a pressure loss per width in the cooling water flow direction of the cooling pipe. The rising temperature ΔT of the cooling water is a temperature increased from the initial cooling water temperature of 65 ° C. That is, the actual temperature of the cooling water is 65 + ΔT ° C. The temperature of the cooling water is a temperature when the temperature of the cooling water is stabilized after the temperature of the cooling water rises as the semiconductor elements 11 and 12 generate heat. That is, the temperature of the cooling water substantially corresponds to the temperature of the semiconductor elements 11 and 12.

  The rising temperature R per unit calorific value is a value of ΔT / 400. Here, the amount of heat generated when the maximum rated current flows through the IGBT element 11 (the amount of heat generated during driving) is 400 W. That is, the rising temperature R per unit calorific value is a value when the IGBT element 11 is applied. For the cooling performance per pressure loss, refer to Table 1 and FIG. As shown in Table 1 and FIG. 6, the cooling performance per pressure loss is the highest in the semiconductor device 1 of the first embodiment, and the second highest in the semiconductor device 2 of the second embodiment. Furthermore, the cooling performance per pressure loss of the semiconductor devices 1 and 2 of the first and second embodiments is much higher than the cooling performance per pressure loss of the conventional first and second semiconductor devices 4 and 5. I understand that it is expensive.

  Based on the above analysis results, the following is considered. First, consider from the viewpoint of pressure loss only. As described above, when the pressure loss is small, a pump having a small maximum discharge pressure can be employed. That is, the semiconductor devices 1 and 2 of the first and second embodiments can use a pump having a smaller maximum discharge pressure than the conventional first and second semiconductor devices 4 and 5. As a result, a low-cost and small-sized pump can be used, whereby the cost and size of the entire device including the semiconductor device can be reduced.

  Next, it considers from a viewpoint of only cooling performance. The rising temperature of the semiconductor device 2 of the second embodiment is the lowest, and the rising temperature of the semiconductor device 1 of the first embodiment is the next lowest. That is, the cooling performance of the cooling pipes of the semiconductor devices 1 and 2 of the first and second embodiments is superior to the cooling performance of the cooling pipes of the first and second semiconductor devices 4 and 5 of the prior art. I understand that.

  As described above, the semiconductor devices 1 and 2 of the first and second embodiments have smaller pressure loss and superior cooling performance than the conventional first and second semiconductor devices 4 and 5. Yes. That is, the semiconductor devices 1 and 2 according to the first and second embodiments can use a pump having a small maximum discharge pressure, and have a high cooling performance.

  Furthermore, the cooling performance per pressure loss will be considered. In general, in the case of a semiconductor device in which the pressure loss of the cooling pipe is equivalent, the semiconductor device having the higher cooling performance per pressure loss can obtain high cooling performance. Further, in the case of a semiconductor device having the same cooling performance of the cooling pipe, the higher the cooling performance per pressure loss, the smaller the pressure loss. That is, when the pressure loss is made equal without making the flow rate of the cooling water constant as the analysis condition, the semiconductor devices 1 and 2 of the first embodiment and the second embodiment have the conventional first and second embodiments. Compared with the semiconductor devices 4 and 5 in FIG. In addition, when the cooling capacities are made equal, the semiconductor devices 1 and 2 of the first and second embodiments have a pressure loss compared to the conventional first and second semiconductor devices 4 and 5. Becomes very small. As a result, the semiconductor devices 1 and 2 of the first and second embodiments can use a pump having a very small maximum discharge pressure.

  Here, the analysis results of the semiconductor device 1 of the first embodiment and the semiconductor device 2 of the second embodiment will be compared and considered. According to the above analysis results, the semiconductor device 1 of the first example has higher cooling performance per pressure loss than the semiconductor device 2 of the second example. This is because the cooling pipe of the semiconductor device 1 of the first embodiment has a larger P1 around the IGBT element 11 having the largest ratio of the amount of heat generated during driving, compared to the cooling pipe of the semiconductor device 2 of the second embodiment. It is said. That is, the semiconductor device 1 of the first embodiment has a high cooling capacity for the IGBT element 11. As described above, the cooling performance as a whole can be improved by increasing the cooling capacity particularly for the IGBT element 11 that generates the largest ratio of the amount of heat generated during driving.

It is sectional drawing of the semiconductor device 1 of 1st Example. It is sectional drawing of the semiconductor device 2 of 2nd Example. It is sectional drawing of the semiconductor device 3 of 3rd Example. FIG. 6 is a cross-sectional view of a conventional first semiconductor device 4. It is sectional drawing of the conventional 2nd semiconductor device 4. FIG. The graph about the cooling performance per pressure loss among analysis results is shown.

Explanation of symbols

1, 2, 3, 4, 5: Semiconductor device, 11: IGBT element (semiconductor element), 12: Diode element (semiconductor element), 13: Lower electrode, electrode (substrate), 14: Upper electrode (substrate), 15, 25, 35: lower cooling pipe, cooling pipe (refrigerant circulation part), 16, 26: upper cooling pipe (refrigerant circulation part), 17: IGBT spacer, 18: diode spacer, 15a, 16a: cylindrical Part, 15b, 16b, 25b, 26b, 35b: fin, P1, P1 ′, P2: fin pitch

Claims (12)

At least one semiconductor element;
A substrate on which the semiconductor element is disposed on the first surface side;
A cylindrical portion formed with a refrigerant flow path on the inner side and joined to the second surface side of the substrate, and a plurality of them are arranged on the inner side of the cylindrical portion along the refrigerant flow direction and in the width direction of the substrate. A refrigerant distribution section comprising fins;
In a semiconductor device comprising:
The semiconductor device, wherein the refrigerant circulation section has different pressure loss per unit flow path according to a distance from the semiconductor element.   The semiconductor device according to claim 1, wherein a pitch of the fins differs according to a position in a direction substantially orthogonal to the refrigerant flow direction.   3. The semiconductor device according to claim 1, wherein a pitch of the fins varies according to a distance from the semiconductor element. The semiconductor element is plural,
3. The semiconductor device according to claim 1, wherein the pitch of the fins varies according to a distance from each of the semiconductor elements and a ratio of a heat generation amount generated when the semiconductor elements are driven. The semiconductor element is plural,
The pitch of the fins varies according to a distance from the semiconductor element having the largest ratio of the amount of heat generated when the semiconductor element is driven among the plurality of semiconductor elements. Semiconductor device.   6. The semiconductor device according to claim 3, wherein a pitch of the fin at a position near the distance from the semiconductor element is larger than a pitch of the fin at a position far from the distance.   The semiconductor device according to claim 3, wherein a pitch of the fins decreases as the distance from the semiconductor element increases.   The fin pitch at a position where the distance from the semiconductor element having the largest heat generation ratio is close is larger than the pitch of the fin at a position where the distance from the semiconductor element having the smallest heat generation ratio is close. The semiconductor device according to claim 5.   3. The semiconductor device according to claim 1, wherein a pitch of the fins varies according to a temperature distribution of the substrate due to heat generation of the semiconductor element.   10. The semiconductor device according to claim 9, wherein a pitch of the fins near the highest temperature in the temperature distribution of the substrate is larger than a pitch of the fins near the lowest temperature in the temperature distribution of the substrate.   The semiconductor device according to claim 1, wherein at least a part of the cylindrical portion and the fin are integrally formed. The substrate is disposed on both sides of the semiconductor element;
The semiconductor device according to claim 1, wherein the coolant circulation part is bonded to a second surface side of each of the substrates.

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