Semiconductor device and power conversion device

Abstract

A semiconductor device (100A, 100B, 100C, 100D, 100E) comprises: a heat spreader (10); a semiconductor element (20); a cooler (40); an insulating layer (50); and a sealing element (70). The heat spreader has a first surface (10a) and a second surface (10b) opposite the first surface. The semiconductor element has a third surface (20a) and a fourth surface (20b) opposite the third surface and is arranged such that the fourth surface faces the first surface. The cooler is arranged to face the first surface, with the insulating layer inserted between them. A flow path (41) through which refrigerant flows is provided in the cooler. The sealing element seals the heat spreader, the semiconductor element, and the cooler. In a top view, a projected area of ​​the cooler is less than or equal to a projected area of ​​the heat spreader.

Description

Semiconductor device and power conversion device

[0001] The present disclosure relates to a semiconductor device and a power conversion device.

[0002] For example, Japanese Patent Laid-Open Publication No. 2018-182105 (Patent Document 1) describes a semiconductor device. The semiconductor device described in Patent Document 1 includes a cooler, a semiconductor element, a lead frame, and a sealing member. The cooler has a first main surface and a second main surface opposite the first main surface. An element pattern layer is disposed on the first main surface. A flow path through which a refrigerant flows is provided inside the cooler.

[0003] The semiconductor element has a front surface and a back surface. The semiconductor element is disposed on an element pattern layer. An electrode on the back surface of the semiconductor element is electrically connected to the element pattern layer by a first bonding material. One end of the lead frame is electrically connected to an electrode on the front surface of the semiconductor element by a second bonding material. The other end of the lead frame is electrically connected to the element pattern layer by a third bonding material. The cooler, the semiconductor element, and the lead frame are sealed with a sealing material.

[0004] Japanese Patent Application Laid-Open No. 2018-182105

[0005] In the semiconductor device described in Patent Document 1, heat generated from the semiconductor element is transmitted through the first bonding material and the element pattern layer and dissipated in the cooler. However, in the semiconductor device described in Patent Document 1, the cooler is large in size, making it difficult to reduce the size.

[0006] The present disclosure has been made in view of the above-described problems of the conventional technology. More specifically, the present disclosure provides a semiconductor device that can achieve both high cooling capacity and miniaturization.

[0007] The semiconductor device of the present disclosure includes a heat spreader, a semiconductor element, a cooler, an insulating layer, and a sealing member. The heat spreader has a first surface and a second surface opposite the first surface. The semiconductor element has a third surface and a fourth surface opposite the third surface, and is arranged so that the fourth surface faces the first surface. The cooler is arranged so that it faces the first surface via the insulating layer. A flow path through which a refrigerant flows is provided inside the cooler. The sealing member seals the heat spreader, the semiconductor element, and the cooler. In a plan view, the projected area of ​​the cooler is equal to or smaller than the projected area of ​​the heat spreader.

[0008] The semiconductor device of the present disclosure can achieve both high cooling capacity and miniaturization.

[0009] 1. A plan view of the semiconductor device 100A. A cross-sectional view taken along line II-II in FIG. 1. A plan view of the semiconductor device 100A according to a modified example. A diagram showing the manufacturing process of the semiconductor device 100A. A cross-sectional view of the semiconductor device 100B. A cross-sectional view of the semiconductor device 100C. A plan view of the semiconductor device 100D. A plan view of the semiconductor device 100E. A plan view of the semiconductor device 100E according to a modified example. A block diagram showing the configuration of a power conversion system 200.

[0010] The details of the embodiments of the present disclosure will be described with reference to the drawings. In the following drawings, the same or corresponding parts are designated by the same reference numerals, and redundant explanations will not be repeated. The following embodiments may be applied in appropriate combinations.

[0011] First Embodiment A semiconductor device according to a first embodiment will be described below. The semiconductor device according to the first embodiment is designated as a semiconductor device 100A.

[0012] (Configuration of Semiconductor Device 100A) The configuration of the semiconductor device 100A will be described below.

[0013] FIG. 1 is a plan view of a semiconductor device 100A. In FIG. 1, the cooler 40 is indicated by a dotted line, and the sealing member 70 is indicated by a dashed line. FIG. 2 is a cross-sectional view taken along line II-II in FIG. 1. FIG. 2 shows a cross section of the semiconductor device 100A perpendicular to a first direction DR1, which will be described later. As shown in FIGS. 1 and 2, the semiconductor device 100A includes a heat spreader 10, a semiconductor element 20, a lead frame 30, the cooler 40, an insulating layer 50, an insulating sheet 60, and a sealing member 70.

[0014] The heat spreader 10 has a first surface 10a and a second surface 10b. The first surface 10a and the second surface 10b are end surfaces of the heat spreader 10 in the thickness direction. The second surface 10b is the surface opposite the first surface 10a. The heat spreader 10 is, for example, a copper plate. The heat spreader 10 is formed, for example, by a press molding method. The surface of the heat spreader 10 may be formed with irregularities such as dimples. This improves adhesion to the sealing member 70 and prevents the sealing member 70 from peeling off from the heat spreader 10 due to thermal stress caused by heat generation during operation of the semiconductor device 100A.

[0015] The semiconductor element 20 has a third surface 20a and a fourth surface 20b. The third surface 20a and the fourth surface 20b are end surfaces of the semiconductor element 20 in the thickness direction. The fourth surface 20b is the surface opposite to the third surface 20a. The semiconductor element 20 is, for example, an insulated gate bipolar transistor (IGBT). The semiconductor element 20 has a first electrode and a second electrode on the third surface 20a and a third electrode on the fourth surface 20b. If the semiconductor element 20 is an IGBT, the first electrode and the second electrode are an emitter electrode and a gate electrode, respectively, and the third electrode is a collector electrode. The first electrode, the second electrode, and the third electrode are formed of, for example, aluminum or an aluminum alloy containing silicon. The semiconductor element 20 is formed using a semiconductor substrate. The semiconductor substrate is formed of a semiconductor material such as silicon, silicon carbide, gallium nitride, or diamond. The semiconductor element 20 is used, for example, in an inverter unit that converts DC power to AC power.

[0016] The semiconductor element 20 is disposed on the heat spreader 10. More specifically, the semiconductor element 20 is disposed so that the fourth surface 20b faces the first surface 10a. The fourth surface 20b is electrically connected to the first surface 10a by a bonding material 80. This electrically connects the third electrode of the semiconductor element 20 to the heat spreader 10. The bonding material 80 is formed of, for example, a solder alloy or sintered silver particles.

[0017] The lead frame 30 has a lead portion 31, a lead portion 32, and a plurality of lead portions 33. The lead frame 30 is formed, for example, by press-forming a copper plate. Although not shown, the surface of the lead frame 30 may be formed with irregularities such as dimples. This improves adhesion to the sealing member 70 and prevents the sealing member 70 from peeling off from the lead frame 30 due to thermal stress caused by heat generation during operation of the semiconductor device 100A. The thickness of the lead frame 30 is preferably smaller than that of the heat spreader 10.

[0018] The lead portion 31 is electrically connected to the semiconductor element 20. More specifically, the lead portion 31 is electrically connected to a first electrode of the semiconductor element 20 by a bonding material 81. The bonding material 81 is formed of, for example, a solder alloy or sintered silver particles. The lead portion 32 is electrically connected to the heat spreader 10. More specifically, the lead portion 32 is electrically connected to the first surface 10a by a bonding material 82 (not shown). The bonding material 82 is formed of, for example, a solder alloy or sintered silver particles.

[0019] The lead portion 33 is electrically connected to the semiconductor element 20. More specifically, the lead portion 33 is electrically connected to the second electrode of the semiconductor element 20 by wire bonding using a wire 83. The wire 83 is made of, for example, copper, iron, nickel, cobalt, aluminum, or an alloy thereof.

[0020] A flow path 41 is provided inside the cooler 40. A refrigerant flows through the flow path 41. The refrigerant is, for example, water, but is not limited to this. Fins 42 are provided inside the cooler 40 to improve cooling efficiency. Pins may be provided inside the cooler 40 instead of the fins 42. The cooler 40 is made of, for example, aluminum, copper, or the like.

[0021] The cooler 40 has a main body 43, a connecting portion 44, and a connecting portion 45. The main body 43 is disposed facing the third surface 20a with a gap therebetween. In a plan view, the refrigerant flows through a flow path 41 in the main body 43 along a first direction DR1. Note that the plan view refers to the case where the semiconductor device 100A is viewed from a direction perpendicular to the third surface 20a.

[0022] The connection portion 44 is connected to one end of the main body portion 43 in the first direction DR1. The connection portion 45 is connected to the other end of the main body portion 43 in the first direction DR1. The connection portions 44 and 45 extend along the first direction DR1 in a plan view. A hose, for example, is connected to the connection portions 44 and 45. For example, a refrigerant is supplied from the hose connected to the connection portion 44. This refrigerant passes through the flow path 41 in the connection portion 44 and flows through the flow path 41 in the main body portion 43. The refrigerant that has flowed through the flow path 41 in the main body portion 43 passes through the flow path 41 in the connection portion 45 and is discharged from the hose.

[0023] In a plan view, the projected area of ​​the cooler 40 is equal to or smaller than the projected area of ​​the heat spreader 10. In a cross-sectional view perpendicular to the first direction DR1, the width of the cooler 40 (main body 43) is preferably equal to or smaller than the width of the heat spreader 10.

[0024] The insulating layer 50 is interposed between the third surface 20a and the cooler 40. More specifically, the insulating layer 50 is interposed between the third surface 20a, to which the lead frame 30 (lead portion 31) is connected, and the cooler 40. The insulating layer 50 electrically insulates the cooler 40 from the semiconductor element 20 (lead frame 30). The insulating layer 50 is made of a thermosetting resin such as an epoxy resin. This thermosetting resin may contain a filler. The filler is made of, for example, silica, alumina, boron nitride, or the like.

[0025] The insulating sheet 60 has a fifth surface 60a and a sixth surface 60b. The fifth surface 60a and the sixth surface 60b are end surfaces of the insulating sheet 60 in the thickness direction. The sixth surface 60b is the surface opposite the fifth surface 60a. The insulating sheet 60 has a metal layer 61 and an insulating layer 62. The metal layer 61 and the insulating layer 62 are superimposed. The fifth surface 60a is composed of the insulating layer 62, and the sixth surface 60b is composed of the metal layer 61. The metal layer 61 is, for example, copper foil, a copper plate, an aluminum plate, or the like. The insulating layer 62 is, for example, formed of a thermosetting resin such as an epoxy resin. This thermosetting resin may contain a filler. This filler is, for example, formed of silica, alumina, boron nitride, or the like. The heat spreader 10 is disposed on the insulating sheet 60 so that the second surface 10b faces the fifth surface 60a.

[0026] The sealing member 70 seals the heat spreader 10, the semiconductor element 20, the lead frame 30, the cooler 40, the insulating layer 50, and the insulating sheet 60. A metal layer 61 is exposed from the sealing member 70. In a plan view, the lead portions 31, 32, and 33 protrude from the outer peripheral edge of the sealing member 70 along the second direction DR2. The second direction DR2 is a direction perpendicular to the first direction DR1 in a plan view. In addition, in a plan view, the connection portions 44 and 45 protrude from the outer peripheral edge of the sealing member 70 along the first direction DR1. None of the lead portions 31, 32, and 33 protruding from the outer peripheral edge of the sealing member 70 in a plan view overlaps with any of the connection portions 44 and 45 protruding from the outer peripheral edge of the sealing member 70 in a plan view.

[0027] The sealing member 70 is formed of, for example, a thermosetting resin. This thermosetting resin is, for example, an epoxy resin, a phenolic resin, or the like. The sealing member 70 is formed by, for example, transfer molding, compression molding, or the like. The sealing member 70 ensures electrical insulation between the components it seals and also functions as a case for the semiconductor device 100A.

[0028] <Modifications> In the above example, an IGBT is given as an example of the semiconductor element 20, but the semiconductor element 20 may also be a bipolar transistor, a MOSFET (Metal Oxide Semiconductor Field Effect Transistor), or a GTO (Gate Turn-Off thyristor). The semiconductor element 20 may also be a diode. When the semiconductor element 20 is a diode, the semiconductor element 20 is used, for example, in a converter unit that converts AC power into DC power.

[0029] 3 is a plan view of a semiconductor device 100A according to a modified example. In FIG. 3, the cooler 40 is indicated by a dotted line. As shown in FIG. 3, the semiconductor device 100A may include a plurality of semiconductor devices 100A. In this case, the lead portion 31 is electrically connected to the first electrode of each of the plurality of semiconductor elements 20.

[0030] (Method for Manufacturing Semiconductor Device 100A) A method for manufacturing the semiconductor device 100A will be described below.

[0031] 4 is a manufacturing process diagram of the semiconductor device 100 A. As shown in FIG. 4, the manufacturing method of the semiconductor device 100 A includes a preparation step S1 and a sealing step S2.

[0032] In the preparation step S1, a heat spreader 10, a semiconductor element 20, a lead frame 30, a cooler 40, an insulating layer 50, and an insulating sheet 60 are prepared. At the preparation step S1 stage, the semiconductor element 20 is connected to the heat spreader 10 with a bonding material 80, the lead portion 31 is connected to the semiconductor element 20 with a bonding material 81, the lead portion 32 is connected to the heat spreader 10 with a bonding material 82, and the lead portion 33 is connected to the semiconductor element 20 with a wire 83. At the preparation step S1 stage, the insulating layer 50 is interposed between the third surface 20a and the cooler 40, and the insulating sheet 60 (insulating layer 62) is attached to the second surface 10b.

[0033] The sealing step S2 is performed after the preparation step S1. In the sealing step S2, first, the heat spreader 10, semiconductor element 20, lead frame 30, cooler 40, insulating layer 50, and insulating sheet 60 prepared in the preparation step S1 are placed inside a mold. At this time, the upper mold presses the lead portions 31, 32, 33, connecting portions 44, and 45 that protrude from the sealing member 70 after the sealing step S2. Second, the uncured sealing member 70 is injected into the space between the upper and lower molds. Note that the pressure applied when injecting the sealing member 70 causes the insulating layer 50 to adhere to the semiconductor element 20 and the cooler 40, and the insulating layer 62 to adhere to the metal layer 61 and the heat spreader 10.

[0034] Third, the sealing member 70 is heated, thereby hardening the sealing member 70. This heating also hardens the insulating layer 50 and the insulating layer 62, bonding the semiconductor element 20 and the cooler 40 together via the insulating layer 50, and bonding the metal layer 61 and the heat spreader 10 together via the insulating layer 62. In this manner, the semiconductor device 100A having the structure shown in FIGS. 1 and 2 is manufactured.

[0035] (Effects of Semiconductor Device 100A) The effects of the semiconductor device 100A will be described below.

[0036] The semiconductor device 100A can be miniaturized because the projected area of ​​the cooler 40 in a plan view is equal to or smaller than the projected area of ​​the heat spreader 10. If the width of the cooler 40 (main body 43) in the first direction DR1 is equal to or smaller than the width of the heat spreader 10, further miniaturization is possible.

[0037] Furthermore, in the semiconductor device 100A, the cooler 40 cools the semiconductor element 20 without diffusing the heat generated in the semiconductor element 20. Although the lead frame 30 (lead portion 31) and the insulating layer 50 are present between the cooler 40 and the semiconductor element 20, these components are not intended to diffuse the heat generated in the semiconductor element 20, and therefore the cooling capacity is unlikely to decrease even if the projected area of ​​the cooler 40 in a plan view is equal to or smaller than the projected area of ​​the heat spreader 10. In this way, the semiconductor device 100A can achieve both high cooling capacity and compact size.

[0038] When none of the lead portions 31, 32, and 33 protruding from the outer peripheral edge of the sealing member 70 in a plan view overlaps with any of the connection portions 44 and 45 protruding from the outer peripheral edge of the sealing member 70 in a plan view, it is possible to prevent the uncured sealing member 70 from flowing out using only the upper and lower molds in the sealing step S2. In particular, when the extending direction of the lead portions 31, 32, and 33 protruding from the outer peripheral edge of the sealing member 70 is perpendicular to the extending direction of the connection portions 44 and 45 protruding from the outer peripheral edge of the sealing member 70, it is possible to simplify the shapes of the upper and lower molds, and it is possible to prevent damage or chipping of the semiconductor device 100A and the mold during demolding.

[0039] Second Embodiment A semiconductor device according to a second embodiment will be described. The semiconductor device according to the second embodiment is designated as semiconductor device 100B. Here, differences from semiconductor device 100A will be mainly described, and overlapping descriptions will not be repeated.

[0040] (Configuration of Semiconductor Device 100B) The configuration of the semiconductor device 100B will be described below.

[0041] 5 is a cross-sectional view of the semiconductor device 100B. FIG. 5 shows a cross-section of the semiconductor device 100B taken along the line II-II in FIG. 1. As shown in FIG. 5, the semiconductor device 100B includes a heat spreader 10, a semiconductor element 20, a lead frame 30, a cooler 40, an insulating layer 50, an insulating sheet 60, and a sealing member 70. The semiconductor device 100B further includes bonding materials 80, 81, and 82 (not shown), as well as wires 83. In these respects, the configuration of the semiconductor device 100B is the same as that of the semiconductor device 100A.

[0042] In the semiconductor device 100B, the sealing member 70 is filled between the third surface 20a and the cooler 40 (between the lead portion 31 and the cooler 40), and the portion of the sealing member 70 filled between the third surface 20a and the cooler 40 functions as the insulating layer 50. In this respect, the configuration of the semiconductor device 100B differs from the configuration of the semiconductor device 100A.

[0043] (Method for Manufacturing Semiconductor Device 100B) A method for manufacturing the semiconductor device 100B will be described below.

[0044] The method for manufacturing the semiconductor device 100B includes a preparation step S1 and a sealing step S2. In this respect, the method for manufacturing the semiconductor device 100B is common to the method for manufacturing the semiconductor device 100A.

[0045] In the manufacturing method of the semiconductor device 100B, in the preparation step S1, the insulating layer 50 is not interposed between the semiconductor element 20 and the cooler 40. Furthermore, in the manufacturing method of the semiconductor device 100B, when the heat spreader 10, the semiconductor element 20, the lead frame 30, the cooler 40, and the insulating sheet 60 are placed inside a mold, a space is left between the semiconductor element 20 and the cooler 40. The sealing member 70 injected into the mold flows into this space. In these respects, the manufacturing method of the semiconductor device 100B differs from the manufacturing method of the semiconductor device 100A.

[0046] (Effects of Semiconductor Device 100B) The effects of the semiconductor device 100B will be described below.

[0047] In the semiconductor device 100B, a portion of the sealing member 70 can function as the insulating layer 50, so there is no need to provide an insulating layer 50 separately from the sealing member 70, and the number of components used can be reduced.

[0048] When providing an insulating layer 50 separate from the sealing member 70, if the insulating layer 50 is not cured at an appropriate time in the sealing step S2, the adhesion between the semiconductor element 20 and the cooler 40 may be insufficient. In the semiconductor device 100B, a part of the sealing member 70 functions as the insulating layer 50, and therefore it is possible to prevent a decrease in adhesion between the semiconductor element 20 and the cooler 40 due to the insulating layer 50 not being cured at an appropriate time.

[0049] Third Embodiment A semiconductor device according to a third embodiment will be described. The semiconductor device according to the third embodiment is designated as semiconductor device 100C. Here, differences from semiconductor device 100A will be mainly described, and overlapping descriptions will not be repeated.

[0050] 6 is a cross-sectional view of the semiconductor device 100C. FIG. 6 shows a cross-section of the semiconductor device 100C taken along the line II-II in FIG. 1. As shown in FIG. 6, the semiconductor device 100B includes a heat spreader 10, a semiconductor element 20, a lead frame 30, a cooler 40, an insulating layer 50, and a sealing member 70. The semiconductor device 100C further includes bonding materials 80, 81, and 82 (not shown), as well as wires 83. In these respects, the configuration of the semiconductor device 100C is common to the configuration of the semiconductor device 100A.

[0051] The semiconductor device 100C has an insulating substrate 63 instead of the insulating sheet 60. The insulating substrate 63 has an insulating base material 64 and conductive layers 65 and 66. The insulating base material 64 has a seventh surface 64a and an eighth surface 64b. The seventh surface 64a and the eighth surface 64b are end surfaces in the thickness direction of the insulating base material 64. The eighth surface 64b is the surface opposite to the seventh surface 64a. The insulating base material 64 is formed of a ceramic material such as alumina, aluminum nitride, or silicon nitride. The thickness of the insulating base material 64 is selected appropriately from the viewpoint of ensuring the necessary dielectric strength voltage.

[0052] The conductive layer 65 is disposed on the seventh surface 64a. The conductive layer 66 is disposed on the eighth surface 64b. The conductive layers 65 and 66 are formed of, for example, copper, aluminum, or the like. In the semiconductor device 100C, the semiconductor element 20 is disposed so that the fourth surface 20b faces the conductive layer 65. In the semiconductor device 100C, the fourth surface 20b and the conductive layer 65 are electrically connected by a bonding material 80, and the conductive layer 65 and the lead portion 32 are electrically connected by a bonding material 82. That is, in the semiconductor device 100C, the conductive layer 65 functions as the heat spreader 10. The thicknesses of the conductive layers 65 and 66 are appropriately selected from the viewpoint of ensuring cooling capacity. From the viewpoint of suppressing warping of the insulating substrate 63, it is preferable that the thicknesses of the conductive layers 65 and 66 are equal.

[0053] In the semiconductor device 100C, similarly to the semiconductor device 100A, the projected area of ​​the cooler 40 in plan view is equal to or smaller than the projected area of ​​the heat spreader 10, so that high cooling capacity and compact size can both be achieved.

[0054] Fourth Embodiment A semiconductor device according to a fourth embodiment will be described. The semiconductor device according to the fourth embodiment is designated as semiconductor device 100D. Here, differences from semiconductor device 100A will be mainly described, and overlapping descriptions will not be repeated.

[0055] (Configuration of Semiconductor Device 100D) The configuration of the semiconductor device 100D will be described below.

[0056] 7 is a plan view of the semiconductor device 100D. As shown in FIG. 7, the semiconductor device 100D includes a heat spreader 10, a semiconductor element 20, a lead frame 30, a cooler 40, an insulating layer 50, an insulating sheet 60, and a sealing member 70. The semiconductor device 100D further includes bonding materials 80, 81, and 82 (not shown). In these respects, the configuration of the semiconductor device 100D is common to the configuration of the semiconductor device 100A.

[0057] The semiconductor device 100D has multiple semiconductor elements 20. More specifically, the semiconductor device 100D has semiconductor elements 20A and 20B. The semiconductor elements 20A and 20B are aligned along the second direction DR2 in a plan view. In the semiconductor device 100D, the lead portions 31 are electrically connected to the third surfaces 20a of the semiconductor elements 20A and 20B by bonding material 81. In the semiconductor device 100D, the cooler 40 has main body portions 46a and 46b, and connecting portions 47a, 47b, and 47c.

[0058] The main body portion 46a and the main body portion 46b are arranged to face the third surface 20a of the semiconductor element 20A and the third surface 20a of the semiconductor element 20B, respectively, with the insulating layer 50 interposed therebetween. The connection portion 47a is connected to one end of the main body portion 46a in the first direction DR1. The connection portion 47b is connected to one end of the main body portion 46b in the first direction DR1. The connection portions 47a and 47b protrude from only one side of the outer periphery of the sealing member 70 in the first direction DR1 in a plan view. The connection portion 47c connects the other end of the main body portion 46a in the first direction DR1 and the other end of the main body portion 46b in the first direction DR1. The connection portion 47c is not exposed from the sealing member 70. In these respects, the configuration of the semiconductor device 100D differs from the configuration of the semiconductor device 100A.

[0059] (Effects of Semiconductor Device 100D) The effects of the semiconductor device 100D will be described below.

[0060] In the semiconductor device 100D, high cooling capacity and miniaturization are both possible even when the semiconductor element 20 is located in an offset position. Furthermore, in the semiconductor device 100D, the connection portions 47a and 47b protrude from only one side of the outer periphery of the sealing member 70 in a plan view. Therefore, even if there is an obstacle around the semiconductor device 100D in the case of the device in which the semiconductor device 100D is installed, the semiconductor device 100D can be placed close to the obstacle, and the device in which the semiconductor device 100D is installed can be miniaturized.

[0061] Fifth Embodiment A semiconductor device according to a fifth embodiment will be described. The semiconductor device according to the fifth embodiment is designated as semiconductor device 100E. Here, differences from semiconductor device 100D will be mainly described, and overlapping descriptions will not be repeated.

[0062] (Configuration of Semiconductor Device 100E) The configuration of the semiconductor device 100E will be described below.

[0063] 8 is a plan view of the semiconductor device 100E. As shown in FIG. 8, the semiconductor device 100E includes a heat spreader 10, a plurality of semiconductor elements 20 (semiconductor elements 20A and 20B), a lead frame 30, a cooler 40, an insulating layer 50, an insulating sheet 60, and a sealing member 70. The semiconductor device 100E further includes bonding materials 80, 81, and 82 (not shown). In these respects, the configuration of the semiconductor device 100E is common to the configuration of the semiconductor device 100D.

[0064] In the semiconductor device 100E, the cooler 40 further includes a connection portion 47d. The connection portion 47d is connected to the connection portion 47c. The connection portion 47d protrudes along the first direction DR1 from the outer periphery of the sealing member 70 in a plan view. The side of the outer periphery of the sealing member 70 from which the connection portion 47d protrudes is on the opposite side in the first direction DR1 to the side of the outer periphery of the sealing member 70 from which the connection portions 47a and 47b protrude. In other words, in the semiconductor device 100E, the number of connection portions of the cooler 40 protruding from the outer periphery of the sealing member 70 in a plan view is three.

[0065] For example, the refrigerant is supplied from a hose connected to connection portion 47d and branches at the connection portion between flow path 41 at connection portion 47d and flow path 41 at connection portion 47c. One of the branched refrigerants flows through flow path 41 at connection portion 47c, flow path 41 at main body portion 46a, and flow path at connection portion 47a, and is discharged from the hose connected to connection portion 47a. The other branched refrigerant flows through flow path 41 at connection portion 47c, flow path 41 at main body portion 46b, and flow path at connection portion 47b, and is discharged from the hose connected to connection portion 47a. In these respects, the configuration of semiconductor device 100E differs from the configuration of semiconductor device 100D.

[0066] <Modification> Fig. 9 is a plan view of a semiconductor device 100E according to a modification. As shown in Fig. 9, in the semiconductor device 100E, the cooler 40 may have a connection portion 47e and a connection portion 47f instead of the connection portion 47d. The connection portion 47e and the connection portion 47f are connected to the other end of the main body portion 46a in the first direction DR1 and the other end of the main body portion 46b in the first direction DR1, respectively. The connection portion 47e and the connection portion 47f protrude along the first direction DR1 from the outer periphery of the sealing member 70 in a plan view.

[0067] The side of the outer periphery of the sealing member 70 from which the connection portions 47e and 47f protrude is on the opposite side in the first direction DR1 to the side of the outer periphery of the sealing member 70 from which the connection portions 47a and 47b protrude. That is, in the semiconductor device 100E, the number of connection portions of the cooler 40 protruding from the outer periphery of the sealing member 70 in a plan view may be three or more.

[0068] When the cooler 40 has the connection portion 47e and the connection portion 47f, the coolant is supplied from the hose connected to the connection portion 47e, flows through the flow path 41 in the connection portion 47e, the flow path 41 in the main body portion 46a, and the flow path 41 in the connection portion 47a, and is discharged from the hose connected to the connection portion 47a. The coolant is supplied from the hose connected to the connection portion 47f, flows through the flow path 41 in the connection portion 47f, the flow path 41 in the main body portion 46b, and the flow path 41 in the connection portion 47b, and is discharged from the hose connected to the connection portion 47b. In this way, in the semiconductor device 100D, the cooler 40 may have multiple independent flow paths 41.

[0069] (Effects of Semiconductor Device 100E) The effects of the semiconductor device 100E will be described below.

[0070] In the semiconductor device 100E, it is possible to branch the flow path 41 of the cooler 40 midway or to provide a plurality of independent flow paths 41 in the cooler 40. Therefore, the semiconductor device 100E can be made smaller and have a further increased cooling capacity.

[0071] Sixth Embodiment In this embodiment, the semiconductor device according to the first to fifth embodiments described above is applied to a power conversion device. Although the present disclosure is not limited to a specific power conversion device, the following describes a case in which the present disclosure is applied to a three-phase inverter as the sixth embodiment. The power conversion system according to the sixth embodiment is referred to as power conversion system 200.

[0072] FIG. 10 is a block diagram showing the configuration of a power conversion system 200. As shown in FIG. 10, the power conversion system is composed of a power source 300, a power conversion device 400, and a load 500. The power source 300 is a DC power source and supplies DC power to the power conversion device 400. The power source 300 can be composed of various elements, such as a DC system, a solar cell, or a storage battery, or it may be composed of a rectifier circuit connected to an AC system or an AC / DC converter. The power source 300 may also be composed of a DC / DC converter that converts DC power output from a DC system into a predetermined power.

[0073] The power conversion device 400 is a three-phase inverter connected between the power source 300 and the load 500, and converts DC power supplied from the power source 300 into AC power and supplies the AC power to the load 500. As shown in Fig. 10 , the power conversion device 400 includes a main conversion circuit 401 that converts DC power into AC power and outputs it, and a control circuit 403 that outputs a control signal to the main conversion circuit 401 to control the main conversion circuit 401.

[0074] The load 500 is a three-phase electric motor driven by AC power supplied from the power conversion device 400. The load 500 is not limited to a specific application, but is an electric motor mounted on various electrical devices, and is used as an electric motor for, for example, a hybrid vehicle, an electric vehicle, a railroad car, an elevator, or an air conditioning device.

[0075] The power conversion device 400 will be described in detail below. The main conversion circuit 401 includes switching elements and freewheel diodes (not shown). The switching elements convert DC power supplied from the power source 300 into AC power, which is supplied to the load 500. While the main conversion circuit 401 can have a variety of specific circuit configurations, the main conversion circuit 401 according to this embodiment is a two-level, three-phase full-bridge circuit that can be configured with six switching elements and six freewheel diodes connected in anti-parallel to each switching element. At least one of the switching elements and freewheel diodes of the main conversion circuit 401 is a switching element or freewheel diode included in a semiconductor module 402 corresponding to the semiconductor device according to any one of the first to fifth embodiments described above. Two of the six switching elements are connected in series to form upper and lower arms, which form each phase (U phase, V phase, and W phase) of the full-bridge circuit. The output terminals of each upper and lower arm, i.e., the three output terminals of the main conversion circuit 401, are connected to the load 500.

[0076] The main conversion circuit 401 includes a drive circuit (not shown) that drives each switching element, but the drive circuit may be built into the semiconductor module 402, or may be provided separately from the semiconductor module 402. The drive circuit generates drive signals that drive the switching elements of the main conversion circuit 401 and supplies them to the control electrodes of the switching elements of the main conversion circuit 401. Specifically, in accordance with control signals from a control circuit 403 (described later), the drive circuit outputs to the control electrodes of each switching element a drive signal that turns the switching element on and a drive signal that turns the switching element off. To maintain a switching element in the on state, the drive signal is a voltage signal (on signal) that is equal to or greater than the threshold voltage of the switching element, and to maintain a switching element in the off state, the drive signal is a voltage signal (off signal) that is equal to or less than the threshold voltage of the switching element.

[0077] The control circuit 403 controls the switching elements of the main conversion circuit 401 so that the desired power is supplied to the load 500. Specifically, it calculates the time (on time) that each switching element of the main conversion circuit 401 should be in the on state based on the power to be supplied to the load 500. For example, the main conversion circuit 401 can be controlled by PWM control, which modulates the on time of the switching elements according to the voltage to be output. The control circuit 403 then outputs a control command (control signal) to a drive circuit included in the main conversion circuit 401 so that an on signal is output to a switching element that should be in the on state at each time point, and an off signal is output to a switching element that should be in the off state at each time point. In accordance with this control signal, the drive circuit outputs an on signal or an off signal as a drive signal to the control electrode of each switching element.

[0078] In the power conversion device 400, the semiconductor devices according to the above-described embodiments 1 to 5 are applied as the semiconductor module 402 constituting the main conversion circuit 401, and therefore it is possible to reduce the current density in the current path from the semiconductor element 20 while suppressing the occurrence of thermal stress around the semiconductor element 20.

[0079] In the present embodiment, an example in which the present disclosure is applied to a two-level three-phase inverter has been described, but the present disclosure is not limited to this and can be applied to various power conversion devices. In the present embodiment, a two-level power conversion device is described, but a three-level or multi-level power conversion device may also be used. In addition, when supplying power to a single-phase load, the present disclosure may also be applied to a single-phase inverter. Furthermore, when supplying power to a DC load, etc., the present disclosure may also be applied to a DC / DC converter or an AC / DC converter.

[0080] Furthermore, the power conversion device to which the present disclosure is applied is not limited to cases in which the above-mentioned load is an electric motor, but can also be used, for example, as a power supply device for an electric discharge machine, a laser processing machine, an induction heating cooker, or a contactless power supply system, and can also be used as a power conditioner for a solar power generation system, a power storage system, etc.

[0081] The embodiments disclosed herein are illustrative in all respects and should not be considered limiting. The basic scope of the present disclosure is defined by the claims, not by the above-described embodiments, and it is intended to include all modifications within the meaning and scope of the claims.

[0082] 10 Heat spreader, 10a First surface, 10b Second surface, 20, 20A, 20B Semiconductor element, 20a Third surface, 20b Fourth surface, 30 Lead frame, 31, 32, 33 Lead portion, 40 Cooler, 41 Flow path, 42 Fin, 43 Main body portion, 44, 45 Connection portion, 46a, 46b Main body portion, 47a, 47b, 47c, 47d, 47e, 47f Connection portion, 50 Insulating layer, 60 Insulating sheet, 60a Fifth surface, 60b Sixth surface, 61 Metal layer, 62 Insulating layer, 63 Insulating substrate, 64 Insulating base material, 64a Seventh surface, 64b Eighth surface, 65, 66 Conductive layer, 70 Sealing member, 80, 81, 82 Bonding material, 83 Wire, 100A, 100B, 100C, 100D, 100E semiconductor device, 200 power conversion system, 300 power supply, 400 power conversion device, 401 main conversion circuit, 402 semiconductor module, 403 control circuit, 500 load, DR1 first direction, DR2 second direction, S1 preparation step, S2 sealing step.

Claims

1. A semiconductor device comprising: a heat spreader; a semiconductor element; a cooler; an insulating layer; and a sealing member; wherein the heat spreader has a first surface and a second surface opposite the first surface; the semiconductor element has a third surface and a fourth surface opposite the third surface, and is arranged so that the fourth surface faces the first surface; the cooler is arranged so that it faces the first surface via the insulating layer; a flow path through which a refrigerant flows is provided inside the cooler; the sealing member seals the heat spreader, the semiconductor element, and the cooler; and wherein, in a plan view, the projected area of ​​the cooler is equal to or less than the projected area of ​​the heat spreader.

2. The semiconductor device according to claim 1, wherein, in a cross-sectional view perpendicular to the direction of the coolant flowing inside the flow channel on the semiconductor element, the width of the flow channel on the semiconductor element is equal to or less than the width of the heat spreader.

3. A semiconductor device as described in claim 1 or claim 2, further comprising a lead frame electrically connected to the third surface, wherein the cooler has at least one connection portion, the lead frame has a lead portion, and the connection portion and the lead portion protrude from the outer peripheral edge of the sealing member in a plan view and do not overlap each other.

4. The semiconductor device according to claim 3, wherein, in a plan view, the direction in which said connection portions extend is perpendicular to the direction in which said lead portions extend.

5. The semiconductor device according to claim 3 or 4, wherein the connection portion protrudes from only one side of the outer periphery of the sealing member in a plan view.

6. The semiconductor device according to claim 3 or 4, wherein the number of said connection portions protruding from the outer periphery of said sealing member in a plan view is three or more.

7. The semiconductor device according to any one of claims 1 to 6, wherein the insulating layer is formed of the sealing material filled between the first surface and the cooler.

8. A semiconductor device according to any one of claims 1 to 7, further comprising an insulating sheet, wherein the heat spreader is disposed on the insulating sheet so that the second surface faces the insulating sheet, and the sealing member further seals the insulating sheet.

9. A semiconductor device according to any one of claims 1 to 8, further comprising an insulating base material, wherein the heat spreader is disposed on the insulating layer so that the second surface faces the insulating base material, the heat spreader and the insulating base material constitute an insulating substrate, and the sealing member further seals the insulating base material.

10. A power conversion device comprising the semiconductor device according to any one of claims 1 to 9, a main conversion circuit that converts input power and outputs it, and a control circuit that outputs a control signal to the main conversion circuit to control the main conversion circuit.

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