Semiconductor device, method for manufacturing semiconductor device, and power conversion device

Abstract

A semiconductor device, a method for manufacturing a semiconductor device, and a power conversion device are obtained that ensure heat dissipation by using a heat dissipation component formed by bending a metal plate to have a plurality of fins. A semiconductor element (1) is joined to a lead frame (2). The lead frame (2) is provided on an insulating layer (3), and a metal base plate (4) is provided on the opposite side of the surface of the insulating layer (3) to the side to which the semiconductor element (1) is joined. The semiconductor element (1), the lead frame (2), the insulating layer (3), and the metal base plate (4) are packaged by a packaging material (5) in such a way that a portion of the lead frame (2) and a portion of the metal base plate (4) are exposed. The portion of the metal base plate (4) exposed from the packaging material (5) is inserted into an opening (61) of a support frame (6). A heat dissipation component (7) is joined to the metal base plate (4) and the support frame (6).

Description

Technical Field

[0001] The present invention relates to a semiconductor device equipped with a heat dissipation component having a plurality of fins, a method for manufacturing the semiconductor device, and a power conversion device. Background Art

[0002] In the past, it is known that a plurality of semiconductor elements are mounted on a circuit substrate, a lead frame, etc., and a semiconductor device is integrated as a whole by a packaging material. Usually, in such a semiconductor device, since the heat generated by the semiconductor elements is large, a metal base plate such as a heat sink for heat dissipation is provided in contact with an insulating layer on which the circuit substrate and the lead frame are mounted. In addition, a heat dissipation component having a plurality of fins arranged therein is mounted on the surface of the metal base plate of the semiconductor device. Grease is applied between the metal base plate and the heat dissipation component in order to reduce the contact thermal resistance. However, there is a risk of deterioration in heat dissipation due to the fact that the thermal conductivity of the grease is very small compared to that of metal, and a phenomenon called pumping out occurs when the grease flows out to the outside due to a thermal cycle. Therefore, a method of joining a heat dissipation component without using a grease is studied.

[0003] For example, in Patent Document 1, a groove is processed on the surface of a metal base plate opposite to the surface on which the power semiconductor element is mounted, and the heat dissipation component is fixed to the groove of the metal base plate by riveting. In this way, when the heat dissipation component is fixed to the metal base plate by riveting, it is necessary to perform complex processing such as grooves on the metal base plate.

[0004] In addition, Patent Document 2 discloses a heat sink having folded fins formed by bending a metal plate and a bottom plate joined to the folded fins, and the heat sink is joined to a conductor layer of an insulating substrate using a joining metal. By using the folded fins, the heat capacity is reduced compared to a normal fin of the same volume, thermal joining such as soldering becomes easier, and complex processing such as grooves is not required.

[0005] In order to efficiently dissipate the heat from the semiconductor element, it is necessary to increase the number of fins and install a large-sized heat dissipation component on the metal base plate. On the other hand, in the case of a semiconductor device in which the packaging material is molded by transfer molding, etc., it is preferred to package the metal base plate and the semiconductor element etc. as a whole for bonding reliability, and the size of the metal base plate is limited by the size of the mold during molding.

[0006] Patent Document 1: Japanese Patent Application Publication No. 2012-49167

[0007] Patent Document 2: Japanese Patent Application Publication No. 2016-174034 Summary of the invention

[0008] However, when using a heat dissipation component formed by bending a metal plate to form a plurality of fins, there is a problem that if the width of the heat dissipation component in the joined surface direction is larger than the width of the metal base plate, the bent shape cannot be maintained, and heat dissipation deteriorates.

[0009] The present invention is made to solve the above-mentioned problems and provides a semiconductor device, a method for manufacturing the semiconductor device, and a power conversion device that ensure heat dissipation using a heat dissipation member having a plurality of fins formed by bending a metal plate.

[0010] The semiconductor device involved in the present invention comprises: a semiconductor element; a lead frame to which the semiconductor element is joined; an insulating layer to which the lead frame is provided; a metal base plate provided on the opposite side of the insulating layer to the side on which the lead frame is provided; a packaging material that packages the semiconductor element, the lead frame, the insulating layer and the metal base plate in a manner in which a portion of the lead frame and a portion of the metal base plate are exposed; a support frame having an opening portion into which an exposed portion of the metal base plate exposed from the packaging material is inserted; and a heat dissipation component having a plurality of fin portions formed by bending a metal plate, the heat dissipation component being fused to the exposed portion of the metal base plate inserted into the opening portion and to the support frame.

[0011] In addition, the manufacturing method of the semiconductor device involved in the present invention has the following steps: joining a semiconductor element to a lead frame; stacking a metal base plate, an insulating layer and a lead frame joined with the semiconductor element on a molding die to form a packaging material that packages the semiconductor element, the lead frame, the insulating layer and the metal base plate in a manner in which a portion of the lead frame and a portion of the metal base plate are exposed; and inserting an exposed portion of the metal base plate exposed from the packaging material into an opening portion of a supporting frame body, and welding a heat dissipation component having a plurality of fin portions formed by bending a metal plate to the portion of the exposed portion inserted into the opening portion and the supporting frame body.

[0012] In addition, the power conversion device according to the present invention comprises: a main conversion circuit having the above-mentioned semiconductor device, the main conversion circuit converting input power and outputting the converted power;

[0013] and a control circuit that outputs a control signal for controlling the main conversion circuit to the main conversion circuit.

[0014] Effects of the Invention

[0015] According to the semiconductor device and power conversion device of the present invention, by inserting the exposed portion of the metal base plate from the packaging material into the opening of the support frame, the heat dissipation component formed by bending the metal plate to form a plurality of fins is joined to both the metal base plate and the support frame, so that the bending shape of each fin of the heat dissipation component can be maintained, and the heat dissipation performance can be ensured. In addition, according to the manufacturing method of the semiconductor device of the present invention, the semiconductor device can be obtained through a simple process. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a cross-sectional view schematically showing the structure of a semiconductor device according to Embodiment 1 of the present invention.

[0017] Figure 2 It is a perspective view schematically showing an exploded structure of the semiconductor device according to the first embodiment of the present invention.

[0018] Figure 3 This is a schematic diagram showing a part of the heat dissipation component of the semiconductor device according to the first embodiment of the present invention.

[0019] Figure 4 It is a perspective view schematically showing the structure of a semiconductor device according to Embodiment 1 of the present invention.

[0020] Figure 5 This is a schematic structural diagram of a semiconductor device according to Embodiment 1 of the present invention fixed to an external case.

[0021] Figure 6 This is a flowchart showing the manufacturing process of the semiconductor device according to the first embodiment of the present invention.

[0022] Figure 7 It is a cross-sectional view schematically showing the structure of a semiconductor device according to Embodiment 2 of the present invention.

[0023] Figure 8 This is a schematic structural diagram of a part of a semiconductor device according to Embodiment 2 of the present invention, which is enlarged.

[0024] Fig. 9 It is a plan view schematically showing the structure of a metal base plate of a semiconductor device according to a second embodiment of the present invention.

[0025] Fig.10 It is a schematic diagram for explaining the manufacturing process of the semiconductor device according to the second embodiment of the present invention.

[0026] Fig.11 This is a perspective view schematically showing the structure of a supporting frame of a semiconductor device according to a third embodiment of the present invention.

[0027] Fig.12It is a plan view schematically showing the structure of a metal base plate of a semiconductor device according to a third embodiment of the present invention.

[0028] Fig.13 It is a cross-sectional view showing a schematic structure of a semiconductor device according to a fourth embodiment of the present invention.

[0029] Fig.14 It is a schematic configuration diagram of a power conversion system to which a power conversion device according to Embodiment 5 of the present invention is applied. DETAILED DESCRIPTION

[0030] Implementation method 1.

[0031] Figure 1 It is a cross-sectional view schematically showing the structure of a semiconductor device according to Embodiment 1 of the present invention. Figure 2 It is an oblique view showing a schematic structure of a semiconductor device according to Embodiment 1 of the present invention after being decomposed in the thickness direction. In the figure, the thickness direction of the semiconductor device is represented by the Z axis, the width direction of the semiconductor device is represented by the Y axis, and the depth direction of the semiconductor device is represented by the X axis. In addition, in the following description, the positive direction of the Z axis is taken as the top and the negative direction is taken as the bottom. In addition, in the following description, unless otherwise specified, the terms such as the same, parallel, perpendicular, and orthogonal include approximately the same, approximately parallel, approximately perpendicular, and approximately orthogonal.

[0032] like Figure 1 As shown, the semiconductor device 100 includes a semiconductor element 1, a lead frame 2, an insulating layer 3, a metal base plate 4, a sealing material 5, a support frame 6, and a heat dissipation member 7. The heat dissipation member 7 is bonded to both the metal base plate 4 and the support frame 6.

[0033] The semiconductor element 1 is bonded to the lead frame 2 via a bonding layer 8 such as solder. The lead frame 2 is provided on the insulating layer 3 to form a wiring circuit. The semiconductor elements 1 are electrically connected to each other, the lead frames 2 are electrically connected to each other, and the semiconductor element 1 and the lead frame 2 are electrically connected to each other via a wire 9 such as an aluminum wire. A metal base plate 4 is provided on the surface of the insulating layer 3 opposite to the surface on which the semiconductor element 1 is bonded.

[0034] The metal base plate 4 is a metal substrate and diffuses the heat conducted from the semiconductor element 1 through the insulating layer 3. The metal base plate 4 is made of a metal material having a high thermal conductivity, such as aluminum or copper.

[0035] The semiconductor element 1 , the lead frame 2 , the insulating layer 3 , and the metal base plate 4 are encapsulated by the encapsulation material 5 in a manner such that a part of the lead frame 2 and a part of the metal base plate 4 are exposed.

[0036] The support frame 6 has an opening 61 in the center portion corresponding to the size of the lower surface of the metal base plate 4. The exposed portion of the metal base plate 4 exposed from the packaging material 5 is inserted into the opening 61 of the support frame 6. The heat dissipation component 7 is joined to the portion of the exposed portion of the metal base plate 4 exposed from the packaging material 5 that is inserted into the opening 61. In addition, the opposite surface of the surface of the support frame 6 on the insulating layer 3 side is joined to the heat dissipation component 7. Here, in order to ensure the reliability of the joining, it is preferred that the surfaces of the metal base plate 4 and the support frame 6 that are joined to the heat dissipation component 7 are located on the same plane with each other.

[0037] The support frame 6 uses, for example, a metal with high rigidity. By using a metal with high rigidity for the support frame 6, the vibration resistance can be improved, and the reliability of the connection between the metal base plate 4, the heat dissipation component 7, and the support frame 6 can be ensured. When a metal with low rigidity such as aluminum is used for the support frame 6, the rigidity can be ensured by setting the thickness to be thick. In addition, in order to improve the rigidity of the support frame 6, it is preferably formed using a plurality of different types of metals. In addition, in order to improve the vibration resistance, the metal base plate 4 and the support frame 6 are preferably fixed to each other by laser welding, riveting, etc.

[0038] Here, in Figure 1 , the opening 61 of the support frame 6 and the surface of the metal base plate 4 opposite to the surface on which the insulating layer 3 is provided are shown as an example in which the area is the same as each other, but a gap or a bonding material such as solder may be interposed between the support frame 6 and the metal base plate 4. Figure 1 3 shows an example in which the support frame 6 is composed of one plate and the opening 61 is a hole provided in the center, but the support frame 6 may be composed of a plurality of plates and the plurality of plates may be arranged so as to provide the opening 61 in the center.

[0039] Figure 3 This is a schematic structural diagram of a part of the heat dissipation component of the semiconductor device according to the first embodiment of the present invention, which is enlarged. Figure 3 (a) shows the overlapping state between the surfaces of the heat dissipation components. Figure 3 (b) shows the state where the heat dissipation components are expanded between the surfaces. Figure 3 As shown in FIG. 1 , the heat dissipation member 7 is formed by bending a thin metal plate multiple times to form a plurality of fins 7a. Each fin 7a has a bent surface 71 facing each other and a folded end 72. When an external force is applied to each fin 7a, it expands and contracts like a spring. Figure 3 The state where the opposite surfaces 71 of (a) overlap is deformed into Figure 3 (b) The state where the opposing surfaces 71 of the fin portion 7a are expanded. If the opposing surfaces 71 of the fin portion 7a are expanded, the contact area between the heat dissipation component 7 and the metal base plate 4 and the support frame 6 is reduced, and heat conduction is not performed efficiently. Figure 3 As shown in (a), the opposing surfaces 71 of the fin portion 7a are overlapped and bent so as to be perpendicular to the surface of the metal base plate 4 to be joined.

[0040] The heat dissipation component 7 has flat portions 7b parallel to the metal base plate 4 and the support frame 6 between adjacent fin portions 7a and at both ends of the arrangement direction of the fin portions 7a. The heat dissipation component 7 is bonded to either the metal base plate 4 or the support frame 6, for example, by laser welding or the like, for each flat portion 7b.

[0041] In this way, by using the heat dissipation component 7 formed by bending a metal plate to form a plurality of fin portions 7a, it is possible to reduce the weight and heat capacity compared to a heat dissipation component in which a base plate and fins are integrally formed by casting or a heat dissipation component in which a plurality of fins are joined to a base plate by riveting or the like, and it is possible to facilitate thermal joining such as welding with the metal base plate 4 and the support frame 6. Here, it is preferred that the heat dissipation component 7 is made of the same metal as the metal base plate 4 and the support frame 6. Thus, when joining by welding, it is possible to join without excessively melting one of them.

[0042] Figure 4 It is a perspective view schematically showing the structure of a semiconductor device according to Embodiment 1 of the present invention. Figure 4 Yes Figure 1 FIG. 1 is a diagram showing a semiconductor device turned upside down so that the side with the heat dissipation component is on the upper side. Figure 4 As shown, the heat dissipation component 7 has a plurality of joint points P with the metal base plate 4 and the support frame 6. Preferably, the heat dissipation component 7 is joined with the metal base plate 4 and the support frame 6, for example, by welding. Since the metals are directly joined to each other by welding without including a joining material such as a grease, an increase in thermal resistance caused by the joining material can be prevented.

[0043] Here, the thickness of the flat portion 7b of the heat sink 7 joined to the metal base plate 4 and the support frame 6 is preferably thinner than the thickness of the metal base plate 4 and the support frame 6. When the heat sink 7 is joined to the metal base plate 4 by laser welding, for example, if the melting range of the heat sink 7 and the metal base plate 4 is expanded by increasing the irradiation time and power of the laser, there is a risk that the insulation property of the insulating layer 3 will deteriorate because excessive heat is applied to the metal base plate 4. By forming the thickness of the heat sink 7 to be thinner than the thickness of the metal base plate 4 and the support frame 6, welding can be performed without applying excessive heat.

[0044] As for the heat dissipation component 7, the larger the number of fin portions 7a and the larger the overall size are, the higher the heat dissipation will be. On the other hand, since the metal base plate 4 is packaged integrally with the semiconductor element 1 and the like when the packaging material 5 is formed, its size is limited by the mold used during molding. Therefore, when the semiconductor device 100 is viewed from above from the side to which the semiconductor element 1 is bonded, the width of the heat dissipation component 7 is larger than the width of the metal base plate 4. At this time, if the heat dissipation component 7 is bonded only to the metal base plate 4, then with respect to the portion of the heat dissipation component 7 extending from the metal base plate 4, the air for air cooling may blow between the opposite surfaces 71 of the fin portions 7a and spread, resulting in concern that the bonding strength may be reduced and the heat dissipation may be deteriorated. Here, the width refers to Figure 1 The length of the semiconductor device 100 in any direction of the width direction (Y-axis direction) and the depth direction (X-axis direction). That is, for the heat dissipation component 7, the width of at least one of the arrangement direction (Y-axis direction) and the direction orthogonal to the arrangement direction (X-axis direction) of the fin portion 7a of the heat dissipation component 7 is larger than the width of the metal base plate 4 in the same direction.

[0045] In this embodiment, the exposed portion of the metal base plate 4 is inserted and fixed to the opening 61 of the support frame 6, and the heat dissipation component 7 is joined to both the exposed portion of the metal base plate 4 inserted into the opening 61 and the support frame 6. Thus, the bent state of the heat dissipation component 7 can be maintained, and the reduction in the bonding strength and the deterioration of the heat dissipation performance can be reduced.

[0046] The support frame 6 is preferably provided so as not to be in direct contact with the sealing material 5 . Figure 1 Arrow K indicates the insulation creeping distance from the lead frame 2 to the metal base plate 4. When the conductive support frame 6 is in contact with the packaging material 5, since the support frame 6 is conductive with the metal base plate 4, the insulation creeping distance from the lead frame 2 protruding from the side of the packaging material 5 to the metal base plate 4 becomes from the lead frame 2 through the packaging material 5 to the support frame 6. By providing the support frame 6 in a manner that does not directly contact the packaging material 5, the insulation creeping distance from the lead frame 2 protruding from the side of the packaging material 5 to the metal base plate 4 can be extended to ensure insulation.

[0047] Figure 5 1 is a schematic diagram showing a structure in which an external housing is fastened to a semiconductor device according to Embodiment 1 of the present invention. Figure 5As shown, in the semiconductor device 100, the support frame 6 is mounted on the grounded external housing 10. The support frame 6 is provided with screw holes, and the semiconductor device 100 is fixed to the external housing 10 by fastening screws 11 to the screw holes of the support frame 6. Since the metal base plate 4, the support frame 6, the heat dissipation component 7 and the screws 11 are formed of conductive components such as metal, the support frame 6 is screwed to the external housing 10, thereby electrically connecting the support frame 6, the metal base plate 4 and the heat dissipation component 7 to each other, and a stable ground potential can be obtained.

[0048] Next, each structural portion of the semiconductor device 100 will be described in detail.

[0049] The semiconductor element 1 is, for example, a diode used in a converter unit that converts input AC power into DC power, a bipolar transistor used in an inverter unit that converts DC power into AC power, an IGBT (Insulated Gate Bipolar Transistor), a MOSFET (Metal Oxide Semiconductor Field Effect Transistor), a GTO (Gate Turn-Off thyristor), or the like.

[0050] The lead frame 2 is formed by punching a copper plate or a steel plate having a thickness of about 0.6 mm into a predetermined shape to form a wiring circuit. Figure 1 As shown, the lead frame 2 has a step portion 2a bent in a manner separated from the insulating layer 3, and the packaging material 5 enters between the step portion 2a and the insulating layer 3. By forming the step portion 2a of the lead frame 2, it is possible to suppress insulation breakdown along the interface between the insulating layer 3 and the packaging material 5. The step portion 2a of the lead frame 2 is formed, for example, by bending or half punching. The height of the step portion 2a of the lead frame 2 is, for example, set to be greater than or equal to 0.1 mm and less than or equal to half the thickness of the lead frame 2, that is, 0.3 mm. By setting it to be greater than or equal to 0.1 mm, it is possible to suppress the generation of holes in the packaging material 5 filled between the insulating layer 3 and the lead frame 2. Moreover, by setting it to be less than or equal to half the thickness of the lead frame 2, that is, 0.3 mm, it is possible to ensure strength.

[0051] The insulating layer 3 is made of an insulating material with high heat dissipation properties, and insulates the lead frame 2 from the metal base plate 4. The heat generated by the semiconductor element 1 is dissipated to the metal base plate 4 via the insulating layer 3. The insulating layer 3 is made of a thermosetting resin such as epoxy resin, and a highly conductive filler such as silicon dioxide, aluminum oxide, and boron nitride is mixed therein.

[0052] The sealing material 5 is formed of a thermosetting resin such as epoxy resin, for example. The sealing material 5 is resin-molded at a high temperature by transfer molding using a mold, for example. Alternatively, injection molding, compression molding, etc. may be used.

[0053] Next, a method for manufacturing the semiconductor device 100 according to the first embodiment of the present invention will be described. Figure 6 This is a flowchart showing the steps of the method for manufacturing the semiconductor device according to the first embodiment of the present invention.

[0054] In the bonding process of the semiconductor element 1, a bonding layer 8 such as solder is applied to a predetermined position on the lead frame 2, and the semiconductor element 1 is bonded to the bonding layer 8 by a reflow process or the like. That is, the applied solder is melted at a high temperature to electrically connect the semiconductor element 1 and the lead frame 2. Next, the semiconductor element 1 and the lead frame 2 are electrically connected by a wire 9. Here, the wire 9 is used, but any component that can be electrically connected may be used.

[0055] Next, in the encapsulation process, the semiconductor element 1, the lead frame 2, the insulating layer 3, and the metal base plate 4 are resin-encapsulated by, for example, transfer molding. The metal base plate 4 is set in a molding die, and the semi-cured insulating layer 3 is stacked on the metal base plate 4. Then, the lead frame 2 to which the semiconductor element 1 is bonded is set on the insulating layer 3. The encapsulation material 5 is injected by a transfer molding machine. Thus, the components formed on the metal base plate 4 are encapsulated by the encapsulation material 5. The encapsulation material 5 covers the semiconductor element 1, a part of the lead frame 2, the insulating layer 3, and a part of the metal base plate 4.

[0056] In the encapsulation process, the resin filling pressure and resin temperature in the molding die cure the resin to form the encapsulation material 5, and at the same time, the semi-cured insulating layer 3 is pressed against the metal base plate 4 via the lead frame 2 and the insulating layer 3 is cured. As a result, the insulating property and heat dissipation property of the insulating layer 3 are improved.

[0057] In addition, in the encapsulation process, it is preferable to make the curing time of the resin constituting the encapsulation material 5 consistent with the curing time of the semi-cured insulating layer 3. If the curing time of the resin constituting the encapsulation material 5 is longer than the curing time of the semi-cured insulating layer 3, the semi-cured insulating layer 3 is cured first, and there is a risk that the tightness between the lead frame 2 and the insulating layer 3 is deteriorated, and the heat dissipation and insulation properties of the semiconductor device 100 are deteriorated.

[0058] After the encapsulation process, the semiconductor device 100 after the encapsulation material 5 is cured is taken out from the molding die, and the required plating process is performed on each component. For example, the surface of the portion of the lead frame 2 exposed from the side of the encapsulation material 5 is plated to form a terminal. If plating has already been performed, this process can also be omitted.

[0059] Next, a joining process of joining the heat dissipation component 7 is performed. The exposed portion of the metal base plate 4 exposed from the packaging material 5 is inserted and fixed to the opening portion 61 of the support frame 6. Next, the heat dissipation component 7 is joined to the portion of the exposed portion of the metal base plate 4 inserted into the opening portion 61 and the support frame 6. Here, the joining method is, for example, welding, and the joining is performed by local melting by irradiating a laser. Since the heat dissipation component 7, the metal base plate 4, and the support frame 6 do not contain a joining material such as a grease, an adhesive, or a solder, but are directly joined between metals by welding, it is possible to prevent an increase in thermal resistance caused by the joining material.

[0060] At this time, if the heat dissipation component 7 floats from the metal base plate 4 or there is a gap, it will lead to deterioration of heat dissipation, so in order to paste without gap, at least one or more joint points P with the metal base plate 4 are provided on the flat portion 7b of the heat dissipation component 7. In addition, it is preferred that the support frame 6 and the metal base plate 4 are fixed to each other by welding, riveting, etc. This can improve vibration resistance.

[0061] After the above process, we can get Figure 1 The semiconductor device 100 shown in FIG. Here, the above steps may be partially reversed or omitted. After that, the semiconductor device 100 is mounted on the external housing 10 . The semiconductor device 100 is fixed to the external housing 10 by tightening the screws 11 into the screw holes provided in the support frame 6 .

[0062] As described above, in the semiconductor device 100 according to the present embodiment, the semiconductor element 1, the lead frame 2, the insulating layer 3, and the metal base plate 4 are packaged by the packaging material 5, and the semiconductor device 100 has: a support frame 6 having an opening 61 for inserting the exposed portion of the metal base plate 4 exposed from the packaging material 5; and a heat dissipation component 7, which is formed by bending a metal plate to form a plurality of fin portions 7a, and the heat dissipation component 7 is joined to the portion of the exposed portion of the metal base plate 4 inserted into the opening 61 and the support frame 6. Thus, even when a heat dissipation component 7 having a width greater than that of the metal base plate 4 is used, each fin portion 7a will not expand, and the bent shape can be maintained, thereby ensuring heat dissipation. In addition, according to the manufacturing method of the semiconductor device 100 according to the present embodiment, the semiconductor device 100 can be obtained through a simple process.

[0063] Implementation method 2.

[0064] In the following, description of the same points as in Embodiment 1 will be omitted, and description will be mainly focused on the differences. Figure 71 is a schematic structural diagram of a semiconductor device according to Embodiment 2 of the present invention. The semiconductor device 101 includes a semiconductor element 1, a lead frame 2, an insulating layer 3, a metal base plate 4, a packaging material 5, a support frame 6, and a heat dissipation component 7. The heat dissipation component 7 is formed by bending a metal plate to form a plurality of fin portions 7a. The heat dissipation component 7 is bonded to both the metal base plate 4 and the support frame 6.

[0065] Figure 8 This is a schematic structural diagram of a part of a semiconductor device according to Embodiment 2 of the present invention, which is enlarged. Figure 8 It will be Figure 7 The enlarged view of the portion surrounded by the dotted line A. Fig. 9 It is a plan view schematically showing the structure of a metal base plate of a semiconductor device according to a second embodiment of the present invention. Fig. 9 This is a top view of the metal base plate from the side where the heat sink is installed. Figure 8 , Fig. 9 As shown, the outer periphery of the metal base plate 4 is formed with a step from the surface 4a provided with the insulating layer 3 to the surface 4b joined to the heat dissipation component 7 so that the surface 4a provided with the insulating layer 3 is wider than the surface 4b joined to the heat dissipation component 7. The metal base plate 4 has two step surfaces parallel to the surface 4a provided with the insulating layer 3 and the surface 4b joined to the heat dissipation component 7 between these surfaces. Here, the first step surface 4c and the second step surface 4d are sequentially formed from the side closer to the surface 4a provided with the insulating layer 3 in the thickness direction of the two step surfaces.

[0066] Fig.10 Schematic diagram for explaining a method for manufacturing a semiconductor device according to Embodiment 2 of the present invention. Fig.10 As shown, the first stepped surface 4c is a surface provided to contact the molding die 12 when the packaging material 5 is molded by transfer molding or the like. Thus, by providing the first stepped surface 4c in contact with the molding die 12, the packaging material 5 is prevented from flowing into the surface 4b of the metal base plate 4 that is bonded to the heat dissipation component 7. Fig.10 3 shows an example in which the upper mold is omitted and only the lower mold is shown, but the upper mold may be provided so as to be in contact with the first step surface 4 c.

[0067] The second step surface 4d is located outside the opening 61 of the support frame 6, does not contact the packaging material 5, and contacts the opposite surface 6a of the support frame 6 to the surface 6b joined to the heat dissipation component 7 to fix the metal base plate 4. In this way, the metal base plate 4 has the first step surface 4c and the second step surface 4d, thereby preventing the support frame 6 and the packaging material 5 from physically contacting. Here, an example with two step surfaces is shown, but it is sufficient as long as there are at least two or more step surfaces.

[0068] Figure 8 Arrow K shows the insulation creeping distance from the lead frame 2 to the metal base plate 4. When the conductive support frame 6 is in contact with the packaging material 5, since the support frame 6 is conductive with the metal base plate 4, the insulation creeping distance from the lead frame 2 protruding from the side of the packaging material 5 to the metal base plate 4 becomes shorter, which may lead to a decrease in insulation and an increase in the size of the package. In the present embodiment, the metal base plate 4 has a first step surface 4c and a second step surface 4d, thereby physically separating the support frame 6 and the packaging material 5, thereby extending the insulation creeping distance from the lead frame 2 protruding from the side of the packaging material 5 to the metal base plate 4, and ensuring insulation.

[0069] The thickness from the second step surface 4d of the metal base plate 4 to the surface 4b joined to the heat sink 7 is designed to be the same as the thickness of the support frame 6. That is, by designing the surface 4b of the metal base plate 4 joined to the heat sink 7 and the surface 6b of the support frame 6 joined to the heat sink 7 to be flush with each other, the reliability of the joining with the heat sink 7 can be ensured.

[0070] Here, in order to prevent the packaging material 5 from flowing in, the first step surface 4c needs to be located on the entire periphery of the metal base plate 4, but as long as the metal base plate 4 is supported by the support frame 6, the second step surface 4d can also be formed only at the four corners of the metal base plate 4.

[0071] As described above, in the present embodiment, when a heat dissipation component 7 that is bent to form a fin portion 7a and has a width greater than that of the metal base plate 4 is used, similarly, by inserting the metal base plate 4 into the support frame 6 formed with the opening 61, the heat dissipation component 7 is joined to both the metal base plate 4 and the support frame 6, thereby maintaining the bent shape of each fin portion 7a and ensuring heat dissipation. Moreover, in the present embodiment, the metal base plate 4 has two stepped surfaces 4c and 4d. Thus, it is possible to prevent the packaging material 5 from detouring to the side of the surface 4b of the metal base plate 4 that is joined to the heat dissipation component 7 during molding, and to set the support frame 6 in a manner that does not directly contact the packaging material 5, thereby ensuring insulation.

[0072] Implementation method 3.

[0073] The following description will omit the description of the same points as in Embodiments 1 and 2, and will focus on the differences. The semiconductor device 102 includes a semiconductor element 1, a lead frame 2, an insulating layer 3, a metal base plate 4, a packaging material 5, a support frame 6, and a heat dissipation component 7. The heat dissipation component 7 is formed by being bent to form a plurality of fin portions 7a, and the heat dissipation component 7 is bonded to both the metal base plate 4 and the support frame 6.

[0074] Fig.11FIG. 2 is a schematic structural diagram showing a support frame of a semiconductor device according to Embodiment 3 of the present invention. Fig.11 As shown, the support frame 6 is provided with four openings 61 , for example. Fig.12 It is a plan view schematically showing the structure of a metal base plate of a semiconductor device according to a third embodiment of the present invention. Fig.12 This is a top view of the metal base plate 4 from the side where the heat dissipation component 7 is mounted. Fig.12 As shown, the metal base plate 4 has a plurality of protrusions 41 protruding toward the heat sink 7 side on the opposite side of the surface 4a on which the insulating layer 3 is provided. The plurality of protrusions 41 are inserted into the opening 61 of the support frame 6 and joined to the heat sink 7. The thickness of the protrusions 41 is formed to be the same as the thickness of the support frame 6, and the surface 4e of the protrusion 41 joined to the heat sink 7 and the surface 6b of the support frame 6 joined to the heat sink 7 are provided on the same plane. The heat sink 7 is joined to both the metal base plate 4 and the support frame 6 by laser welding or the like.

[0075] The surface 4f of the metal base plate 4 located around the protrusion 41 on the opposite side of the surface 4a on which the insulating layer 3 is provided is provided to contact the opposite side 6a of the support frame 6 to the surface 6b joined to the heat dissipation member 7. In this way, by providing a plurality of openings 61 in the support frame 6, the contact area between the metal base plate 4 and the support frame 6 can be increased, thereby improving the vibration resistance.

[0076] In addition, it is preferred that the metal base plate 4 has at least one stepped surface 4c formed on the outer periphery in such a manner that the surface on the insulating layer 3 side in the width direction is wider than the surface on the heat dissipation component 7 side. The stepped surface 4c is provided so as to contact the molding die 12 when molding the packaging material 5. Thus, the support frame 6 can be provided in a manner not to directly contact the packaging material 5.

[0077] Here, an example is shown in which the number of opening portions 61 of the support frame 6 is four, and correspondingly, the number of surfaces 4e of the metal base plate 4 that are in contact with the heat dissipation component 7 is four. However, the number of opening portions 61 is not limited to four, and may be two, three, or greater than or equal to four.

[0078] As described above, in the present embodiment, when a heat dissipation component 7 is used, which is formed by bending a metal plate to form a plurality of fin portions 7a and has a width greater than that of the metal base plate 4, the heat dissipation component 7 is similarly joined to both the metal base plate 4 and the support frame 6 by inserting the metal base plate 4 into the support frame 6 having the opening portion 61, thereby maintaining the bent shape and ensuring heat dissipation. In addition, in the present embodiment, a plurality of opening portions 61 are provided in the support frame 6, and the metal base plate 4 has convex portions 41, which are inserted into the four opening portions 61 of the support frame 6, respectively, in the exposed portion exposed from the packaging material 5. Thus, the contact area between the metal base plate 4 and the support frame 6 can be increased, and the vibration resistance can be improved.

[0079] Implementation method 4.

[0080] Fig.13 1 is a cross-sectional view showing a schematic structure of a semiconductor device according to a fourth embodiment of the present invention. Hereinafter, descriptions of points common to those in the first to third embodiments will be omitted, and descriptions will be focused on points of difference. In the second embodiment, an example in which a second stepped surface 4d is provided on the metal base plate 4 is shown, but in the present embodiment, the metal base plate 4 and the support frame 6 are fixed by providing the opening 61 of the metal base plate 4 and the support frame 6 in a tapered shape.

[0081] The semiconductor device 103 has a semiconductor element 1, a lead frame 2, an insulating layer 3, a metal base plate 4, a packaging material 5, a support frame 6 and a heat dissipation component 7. The heat dissipation component 7 has a plurality of fin portions 7a by bending a metal plate. The heat dissipation component 7 is joined to both the metal base plate 4 and the support frame 6.

[0082] like Fig.13 As shown, the opening 61 of the support frame 6 is a tapered shape inclined so that the opening width becomes wider on the side of the insulating layer 3. In addition, the metal base plate 4 is a tapered shape in which the surface 4a provided with the insulating layer 3 is wider than the surface 4b joined to the heat dissipation component 7. When the metal base plate 4 is inserted into the opening 61 of the support frame 6, the support frame 6 is fixed to the metal base plate 4 in the middle of the taper in a state where it is physically separated from the packaging material 5.

[0083] As described above, in the present embodiment, when a heat dissipation component 7 is used, which is formed by bending a metal plate to form a plurality of fins 7a and has a width greater than that of the metal base plate 4, the metal base plate 4 is inserted into the support frame 6 having the opening 61, and the heat dissipation component 7 is joined to both the metal base plate 4 and the support frame 6, thereby maintaining the bent shape of each fin 7a and ensuring heat dissipation. In addition, in the present embodiment, by setting the outer side surface of the metal base plate 4 and the inner side surface of the opening 61 of the support frame 6 into a tapered shape, the support frame 6 and the packaging material 5 can be fixed separately, and the insulation creepage distance from the lead frame 2 to the metal base plate 4 can be ensured.

[0084] In addition, in the first to fourth embodiments, the heat dissipating member 7 is formed of one metal plate, but a plurality of metal plates may be used, for example, two or three. By using a plurality of metal plates, the rigidity can be improved.

[0085] Implementation method 5.

[0086] This embodiment applies the semiconductor devices according to the above-mentioned Embodiments 1 to 4 to a power conversion device. The present invention is not limited to a specific power conversion device, but the case where the present invention is applied to a three-phase inverter will be described below as Embodiment 5.

[0087] Fig.14 It is a block diagram showing the configuration of a power conversion system to which the power conversion device according to the present embodiment is applied.

[0088] Fig.14 The power conversion system shown is composed of a power supply 200, a power conversion device 300, and a load 400. The power supply 200 is a DC power supply, and supplies DC power to the power conversion device 300. The power supply 200 can be composed of various power supplies, for example, it can be composed of a DC system, a solar cell, a storage battery, or a rectifier circuit connected to an AC system, or an AC / DC converter. In addition, the power supply 200 can also be composed of a DC / DC converter that converts the DC power output from the DC system into a predetermined power.

[0089] The power conversion device 300 is a three-phase inverter connected between the power source 200 and the load 400, converts the DC power supplied from the power source 200 into AC power, and supplies the AC power to the load 400. Fig.14 As shown, the power conversion device 300 includes: a main conversion circuit 301 that converts DC power into AC power and outputs it; and a control circuit 303 that outputs a control signal for controlling the main conversion circuit 301 to the main conversion circuit 301 .

[0090] Load 400 is a three-phase motor driven by AC power supplied from power converter 300. Load 400 is not limited to a specific use, and is a motor mounted on various electrical devices, for example, a motor for hybrid vehicles, electric vehicles, railway vehicles, elevators, or air conditioners.

[0091] The details of the power conversion device 300 are described below. The main conversion circuit 301 has a switching element and a freewheeling diode (not shown), and the DC power supplied from the power supply 200 is converted into AC power by turning the switching element on and off, and supplied to the load 400. The specific circuit structure of the main conversion circuit 301 is various, but the main conversion circuit 301 involved in this embodiment is a 2-level three-phase full-bridge circuit, which can be composed of 6 switching elements and 6 freewheeling diodes respectively connected in anti-parallel with the switching elements. At least one of the switching elements and freewheeling diodes of the main conversion circuit 301 is composed of a semiconductor device 302 corresponding to any one of the above-mentioned embodiments 1 to 4. The 6 switching elements are connected in series two by two to form upper and lower bridge arms, and each upper and lower bridge arm constitutes each phase (U phase, V phase, W phase) of the full-bridge circuit. Moreover, the output terminals of each upper and lower bridge arm, that is, the three output terminals of the main conversion circuit 301, are connected to the load 400.

[0092] In addition, the main conversion circuit 301 has a driving circuit (not shown) for driving each switching element, but the driving circuit can also be built into the semiconductor device 302, or can also be a structure having a driving circuit separate from the semiconductor device 302. The driving circuit generates a driving signal for driving the switching element of the main conversion circuit 301, and supplies it to the control electrode of the switching element of the main conversion circuit 301. Specifically, according to the control signal from the control circuit 303 described later, the driving signal for turning the switching element into the on state and the driving signal for turning the switching element into the off state are output to the control electrode of each switching element. When the switching element is maintained in the on state, the driving signal is a voltage signal (on signal) greater than or equal to the threshold voltage of the switching element, and when the switching element is maintained in the off state, the driving signal is a voltage signal (off signal) less than or equal to the threshold voltage of the switching element.

[0093] The control circuit 303 controls the switch elements of the main conversion circuit 301 so that the desired power is supplied to the load 400. Specifically, the time (on time) when each switch element of the main conversion circuit 301 should be in the on state is calculated based on the power to be supplied to the load 400. For example, the main conversion circuit 301 can be controlled by PWM control that modulates the on time of the switch element corresponding to the voltage to be output. In addition, the control instruction (control signal) is output to the drive circuit of the main conversion circuit 301 so that the on signal is output to the switch element that should be in the on state and the off signal is output to the switch element that should be in the off state at each moment. The drive circuit outputs the on signal or the off signal as a drive signal to the control electrode of each switch element according to the control signal.

[0094] In the power conversion device according to the present embodiment, since the semiconductor devices 100 to 103 according to the first to fourth embodiments are used for the switching elements and the freewheeling diodes constituting the main conversion circuit 301, heat dissipation can be ensured.

[0095] In this embodiment, an example of applying the present invention to a 2-level three-phase inverter is described, but the present invention is not limited to this and can be applied to various power conversion devices. In this embodiment, a 2-level power conversion device is used, but a 3-level or multi-level power conversion device can be used. When power is supplied to a single-phase load, the present invention can also be applied to a single-phase inverter. In addition, when power is supplied to a DC load, the present invention can also be applied to a DC / DC converter and an AC / DC converter.

[0096] In addition, the power conversion device to which the present invention is applied is not limited to the case where the above-mentioned load is an electric motor. For example, it can also be used 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.

[0097] Furthermore, the present invention may appropriately combine a plurality of components disclosed in Embodiments 1 to 5 without departing from the gist of the present invention.

[0098] Description of the label

[0099] 1 semiconductor element, 2 lead frame, 3 insulating layer, 4 metal base plate, 5 packaging material, 6 support frame, 7 heat dissipation component, 8 bonding layer, 9 wire, 10 external shell, 11 screw, 12 molding die, 100, 101, 102, 103, 302 semiconductor device, power supply 200, 300 power conversion device, 301 main conversion circuit, 303 control circuit, 400 load.

Claims

1. A semiconductor device, characterized in that: have: Semiconductor components; a lead frame to which the semiconductor element is bonded; an insulating layer provided with the lead frame; a metal base plate disposed on a surface of the insulating layer opposite to a surface on which the lead frame is disposed; a packaging material that packages the semiconductor element, the lead frame, the insulating layer, and the metal base plate in a manner that a portion of the lead frame and a portion of the metal base plate are exposed; a supporting frame having an opening into which a portion of the metal base plate exposed from the packaging material is inserted; as well as A heat dissipation component having a plurality of fins formed by bending a metal plate, The bottom surface of the exposed portion of the metal base plate inserted into the opening is flat as a whole. The heat dissipation member has flat portions between the fin portions, respectively, and the plurality of flat portions are welded to the planar bottom surface or the support frame.

2. The semiconductor device according to claim 1, wherein: The thickness of the flat portion of the heat dissipation member is smaller than the thickness of the metal base plate and the support frame.

3. The semiconductor device according to claim 1 or 2, characterized in that: The support frame is configured not to be in contact with the packaging material.

4. The semiconductor device according to claim 1 or 2, characterized in that: The metal base plate has at least two step surfaces parallel to the surface provided with the insulating layer between the surface provided with the insulating layer and the surface bonded to the heat dissipation component, such that the surface provided with the insulating layer is wider than the surface bonded to the heat dissipation component.

5. The semiconductor device according to claim 1 or 2, characterized in that: The support frame has a plurality of the openings, and the exposed portions of the metal base plate that are exposed from the sealing material are respectively inserted into the plurality of openings.

6. The semiconductor device according to claim 1 or 2, characterized in that: The openings of the metal base plate and the support frame have a tapered shape that widens from the heat dissipation member side toward the insulation layer side.

7. The semiconductor device according to claim 1 or 2, characterized in that: The support frame is a conductive component and is arranged on a grounded external shell.

8. The semiconductor device according to claim 1 or 2, characterized in that: The metal base plate and the heat dissipation component are made of the same metal.

9. A method for manufacturing a semiconductor device, characterized in that: The process is as follows: bonding the semiconductor element to the lead frame; Laying a metal base plate, an insulating layer, and the lead frame joined with the semiconductor element on a molding die to form a packaging material that packages the semiconductor element, the lead frame, the insulating layer, and the metal base plate in a manner that a portion of the lead frame and a portion of the metal base plate are exposed; as well as The exposed portion of the metal base plate which is exposed from the packaging material and has a planar bottom surface is inserted into the opening of the support frame, and the flat portion of the heat dissipation component which has a plurality of fin portions formed by bending a metal plate and has a flat portion arranged between the fin portions is welded to the exposed portion and inserted into the planar bottom surface of the opening or the support frame.

10. A power conversion device, characterized in that: have: A main conversion circuit, comprising a semiconductor device according to any one of claims 1 to 8, wherein the main conversion circuit converts input power and outputs the converted power; as well as A control circuit outputs a control signal for controlling the main conversion circuit to the main conversion circuit.

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