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

Abstract

The semiconductor device according to the present invention comprises a base member, a semiconductor substrate mounted on a surface of the base member, and a housing fixed to the surface of the base member so as to enclose the semiconductor substrate. The base member includes: a protruding part provided along a mounting area of the semiconductor substrate and formed so as to protrude from the surface of the base member; and a groove part formed along an edge on the mounting area side of the protruding part and formed so as to be recessed from the surface of the base member.

Description

Semiconductor device, power conversion device, and method of manufacturing the semiconductor device

[0001] The present invention relates to a semiconductor device, a power conversion device, and a method for manufacturing a semiconductor device.

[0002] Patent Document 1 discloses a power semiconductor module including a semiconductor element. The power semiconductor module disclosed in Patent Document 1 includes an insulating substrate on which the semiconductor element is mounted. The insulating substrate is joined to a cooler via a solder layer.

[0003] JP 2018-182175 A

[0004] In a semiconductor device in which a semiconductor substrate having semiconductor elements is mounted on a base member such as a cooler, such as the power semiconductor module disclosed in Patent Document 1, the semiconductor substrate is bonded to the base member in a reflow process. At this time, the semiconductor substrate is positioned on the surface of the base member using a jig. However, such a jig may be difficult to remove due to thermal contraction during the reflow process. Therefore, it is desirable to be able to bond the semiconductor substrate to the base member without using a jig.

[0005] For example, as disclosed in Patent Document 1, by providing a recess in a base member that can accommodate the entire semiconductor substrate, it is possible to position the semiconductor substrate without using a jig. However, multiple semiconductor substrates are mounted on the base member. Therefore, providing multiple recesses large enough to accommodate the semiconductor substrates would result in a wide area of ​​the base member being thin-walled. To avoid this, for example, it is possible to provide a protrusion that protrudes from the surface of the base member so as to fit the mounting area of ​​the semiconductor substrate. However, a fillet is generated at the boundary between the protrusion and the surface of the base member, and the semiconductor substrate may ride up on this fillet, causing the semiconductor substrate to tilt.

[0006] The present invention has been made in consideration of the above-mentioned problems, and aims to enable accurate positioning of a semiconductor substrate relative to a base member in a semiconductor device in which a semiconductor substrate is mounted on a base member without using a jig.

[0007] The present invention employs the following configuration as a means for solving the above problems.

[0008] A first aspect of the present invention is a semiconductor device comprising a base member, a semiconductor substrate mounted on a surface of the base member, and a housing fixed to the surface of the base member so as to surround the semiconductor substrate, wherein the base member has a protrusion that is arranged along the mounting area of ​​the semiconductor substrate and that protrudes from the surface of the base member, and a groove that is formed along the edge of the protrusion on the mounting area side and that is recessed from the surface of the base member.

[0009] A second aspect of the present invention is a power conversion device that includes the semiconductor device according to the first aspect of the present invention and has a power conversion circuit at least a part of which is formed by the semiconductor substrate.

[0010] A third aspect of the present invention is a method for manufacturing a semiconductor device, comprising a semiconductor substrate placement step of placing a semiconductor substrate on a surface of a base member, and a heating step of heating the base portion on which the semiconductor substrate is placed, wherein the base member has a protrusion that is provided along the mounting area of ​​the semiconductor substrate and that protrudes from the surface of the base member, and a groove that is formed along the edge of the protrusion on the mounting area side and that is recessed from the surface of the base member, and wherein the semiconductor substrate placement step places the semiconductor substrate in the mounting area.

[0011] In the present invention, a protrusion is provided on a base member along the mounting area. Therefore, the semiconductor substrate can be placed on the base member using the protrusion as a guide, and the semiconductor substrate can be placed on the base member without using a jig. Furthermore, a groove is provided on the edge of the protrusion on the mounting area side. Therefore, in the present invention, a fillet does not occur at the boundary between the protrusion and the surface of the base member, and the semiconductor substrate can be prevented from riding on the fillet and tilting. Therefore, in a semiconductor device in which a semiconductor substrate is mounted on a base member, the present invention allows the semiconductor substrate to be accurately placed on the base member without using a jig.

[0012] FIG. 1 is a circuit diagram showing a schematic electrical configuration of a power conversion device according to one embodiment of the present invention; FIG. 2 is an exploded perspective view showing a schematic structural configuration of a power conversion device according to one embodiment of the present invention; FIG. 3 is a schematic exploded perspective view of a power module provided in a power conversion device according to one embodiment of the present invention; FIG. 4 is a schematic cross-sectional view including a power device provided in a power conversion device according to one embodiment of the present invention; FIG. 5 is a schematic view of one positioning protrusion and groove provided in a power conversion device according to one embodiment of the present invention, viewed from the stacking direction; FIG. 6 is a flowchart showing a part of a manufacturing process for a power module according to one embodiment of the present invention; and FIG. 7 is a schematic cross-sectional view showing a modified example of a power module according to one embodiment of the present invention.

[0013] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a semiconductor device, a power conversion device, and a method for manufacturing a semiconductor device according to the present invention will be described below with reference to the drawings.

[0014] 1 is a circuit diagram showing a schematic electrical configuration of a power conversion device 1 of this embodiment. The power conversion device 1 of this embodiment is mounted on a vehicle such as an electric automobile and is provided between a motor M and a battery B. The power conversion device 1 of this embodiment performs power conversion between the motor M and the battery B. For example, the power conversion device 1 of this embodiment converts DC power supplied from the battery B into three-phase AC power and supplies it to the motor M. The power conversion device 1 also converts regenerative power (AC power) from the motor M into DC power and supplies it to the battery B.

[0015] As shown in Fig. 1 , the power conversion device 1 of this embodiment includes a power conversion circuit H. As described above, the power conversion circuit H converts DC power into AC power. The power conversion circuit H also converts AC power into DC power. The power conversion circuit H includes a capacitor C and an inverter circuit E. The power conversion device 1 may also include, for example, a step-up / step-down converter or a DC / DC converter (not shown).

[0016] The power conversion device 1 of this embodiment also includes a conductive line BU through which power is conducted. For example, the power conversion device 1 of this embodiment includes a conductive line BU that connects the inverter circuit E and the battery B, and a conductive line BU that connects the inverter circuit E and the motor M.

[0017] As shown in FIG. 1 , the inverter circuit E includes three legs R corresponding to the respective phases of the motor M. Each leg R includes an upper arm HA and a lower arm LA. The upper arm HA is connected to the positive electrode side of a battery B via a conductive line BU. The lower arm LA is connected to the negative electrode side of the battery B via a conductive line BU. The upper arm HA and the lower arm LA are connected in series. An output terminal that connects the legs R and the motor M is connected between the upper arm HA and the lower arm LA.

[0018] 1, the power conversion device 1 of this embodiment includes power devices 20 (semiconductor substrates) corresponding to each leg R. That is, in this embodiment, the power conversion device 1 includes three power devices 20. Each power device 20 includes a power transistor corresponding to the upper arm HA and a power transistor corresponding to the lower arm. That is, in this embodiment, each power device 20 includes two power transistors. Each of these power transistors is formed using a plurality of semiconductor elements.

[0019] Fig. 2 is an exploded perspective view showing a schematic structural configuration of the power conversion device 1 of this embodiment. As shown in Fig. 2, the power conversion device 1 of this embodiment includes an inverter case 2, an intelligent power module 3, and a capacitor unit 4. Note that the power conversion device 1 may also include other components such as a reactor unit forming a step-up / step-down circuit and a DC-DC converter unit forming a DC-DC converter.

[0020] The inverter case 2 is a case that houses the intelligent power module 3, the capacitor unit 4, etc., and includes a center plate 2a and a case cover 2b. The center plate 2a and the case cover 2b are formed as separate parts that can be detached from each other. Note that FIG. 2 illustrates a state in which the case cover 2b is separated above the center plate 2a. However, the installation posture of the power conversion device 1 is not particularly limited. In other words, the power conversion device 1 may be mounted on a vehicle so that the case cover 2b is located to the side of the center plate 2a.

[0021] The central plate 2a has a bottom wall to which the intelligent power modules 3 and the capacitor units 4 are fixed, and side walls that surround the intelligent power modules 3 and the capacitor units 4. In other words, the central plate 2a is formed in the shape of a container that is open on the case cover 2b side. Such central plate 2a is provided with water channels as necessary, and is formed to be able to guide the coolant that cools the intelligent power modules 3 and the capacitor units 4.

[0022] The case cover 2b is fixed to the center plate 2a and covers the intelligent power modules 3 and the capacitor units 4. That is, the intelligent power modules 3 and the capacitor units 4 are exposed when the case cover 2b is detached from the center plate 2a.

[0023] Such an inverter case 2 is fixed to, for example, a housing (not shown) that covers the motor M or a gear case that houses a gear that transmits power generated by the motor M to the outside. In such a case, for example, the center plate 2a is fastened to the motor housing or the gear case using a bolt (not shown) or the like. Note that if the housing that covers the motor M has a space for accommodating the power conversion device 1, the case cover 2b may be omitted.

[0024] The inverter case 2 also holds bus bars that form part or all of the conductive line BU (see FIG. 1) that connects the battery B with the intelligent power module 3 and the capacitor unit 4, and the conductive line BU (see FIG. 1) (not shown) that connects the intelligent power module 3 with the motor M. Note that these bus bars are omitted in FIG. 1.

[0025] The intelligent power module 3 includes a power module 3a (semiconductor device) and a substrate unit 3b. The power module 3a is a module provided with a plurality of power devices 20 (described later). In other words, the power module 3a forms an inverter circuit E with the plurality of power devices 20.

[0026] The board unit 3b is stacked on the power module 3a. This board unit 3b includes, for example, a gate driver board and an ECU (Electronic Control Unit) board. The gate driver board is a board provided with a gate driver that generates a drive signal for the inverter circuit E formed by the power module 3a. The ECU board is a board provided with an ECU that controls the gate driver board.

[0027] The capacitor unit 4 is a unit that houses a capacitor element therein. The capacitor unit 4 is connected to the power module 3a. The capacitor unit 4 forms the capacitor C shown in FIG. 1.

[0028] 3 is a schematic exploded perspective view of a power module 3a included in the intelligent power module 3. As shown in this figure, the power module 3a includes a module case 10 (housing), the above-mentioned power device 20 (semiconductor substrate), and a heat sink 30 (base member).

[0029] The module case 10 is a resin case that houses the power devices 20 and the like. The module case 10 has an opening for each power device 20 to house the power device 20. The module case 10 is fixed onto the heat sink 30 via, for example, an adhesive.

[0030] Such a module case 10 is fixed to a surface 30a of a heat sink 30 so as to surround each of the power devices 20. The power conversion device 1 of this embodiment also includes a bus bar 40 (conductive member) whose middle portion is molded into the module case 10. In this embodiment, the power conversion device 1 of this embodiment includes a bus bar 40 (hereinafter referred to as a bus bar 41) that conducts power between the battery B and the power devices 20, and a bus bar (hereinafter referred to as a bus bar 42) that conducts power between the power devices 20 and the motor M.

[0031] The bus bar 41 is molded into the module case 10 with the connection terminal 41a on the battery B side and the connection terminal 41b on the power device 20 side exposed from the module case 10. In other words, the bus bar 41 has an intermediate portion between the connection terminal 41a and the connection terminal 41b molded into the module case 10. The connection terminal 41a is connected to the capacitor unit 4 and a power supply terminal (not shown), and is connected to the battery B via the power supply terminal.

[0032] The connection terminal 41b is joined to the power device 20. In this embodiment, the connection terminal 41b is joined to the power device 20 by ultrasonic bonding. The connection terminal 41b and the power device 20 that are ultrasonically bonded in this manner are directly connected to each other without using solder, and are joined by atomic force.

[0033] The bus bar 42 is molded into the module case 10 with the connection terminal 42a on the motor M side and the connection terminal 42b on the power device 20 side exposed from the module case 10. In other words, the bus bar 42 has an intermediate portion between the connection terminal 42a and the connection terminal 42b molded into the module case 10. The connection terminal 42a is connected to a connection terminal (not shown) of the motor M.

[0034] The connection terminal 42b is joined to the power device 20. In this embodiment, the connection terminal 42b is joined to the power device 20 by ultrasonic bonding. The connection terminal 42b and the power device 20 that are ultrasonically bonded in this manner are directly connected to each other without using solder, and are joined by atomic force.

[0035] Fig. 4 is a schematic cross-sectional view including a power device 20. Note that the bus bar 40 is omitted in Fig. 4. As shown in Fig. 4, each power device 20 includes an insulating substrate 21, a top conductor layer 22, a bottom conductor layer 23, and a semiconductor element 24. The insulating substrate 21 is made of an insulating material such as ceramics and is formed in a sheet shape.

[0036] A top-side conductor layer 22 is formed on one surface of the insulating substrate 21 (the surface facing the semiconductor element 24). This top-side conductor layer 22 is a metal layer that is electrically connected to the semiconductor element 24 and forms part of a conductive circuit. A bottom-side conductor layer 23 is formed on the other surface of the insulating substrate 21 (the surface opposite the semiconductor element 24). This bottom-side conductor layer 23 forms part of a heat transfer path that transfers heat from the semiconductor element 24 and the like to the heat sink 30. The surface of the bottom-side conductor layer 23 opposite the insulating substrate 21 is a mounting surface 23a when the power device 20 is mounted on the heat sink 30. This mounting surface 23a is joined to the heat sink 30 via solder 50, as shown in FIG. 4 .

[0037] 4 , the back-side conductor layer 23 is formed smaller than the insulating substrate 21 when viewed from the stacking direction of the power device 20 and the heat sink 30. The back-side conductor layer 23 is formed relative to the insulating substrate 21 so that the edge portion 21 a of the insulating substrate 21 is exposed. In other words, the edge portion 21 a of the insulating substrate 21 protrudes laterally (in a direction perpendicular to the stacking direction) beyond the back-side conductor layer 23.

[0038] For example, the semiconductor element 24 is mounted on the front conductor layer 22. There is no limit to the number of semiconductor elements 24 mounted on the front conductor layer 22. Such semiconductor elements 24 can be formed using a silicon (Si) semiconductor. Alternatively, the semiconductor elements 24 can be formed using a wide-gap semiconductor such as a silicon carbide (SiC) semiconductor or a gallium nitride (GaN) semiconductor.

[0039] Each power device 20 is placed on a heat sink 30 and accommodated in an opening of the module case 10. The heat sink 30 supports the module case 10 and the power devices 20. The heat sink 30 also absorbs heat from the power devices 20 to cool them. The heat sink 30 is fixed to the central plate 2a so that the bottom surface thereof is exposed to a flow path provided in the central plate 2a. The heat sink 30 may have a plurality of fins formed on the bottom surface.

[0040] 3 and 4 , in this embodiment, the heat sink 30 has a positioning protrusion 31 (protrusion) and a groove 32. The positioning protrusion 31 is formed to protrude from the surface 30a of the heat sink 30. The protrusion dimension of this positioning protrusion 31 from the surface 30a is greater than the thickness dimension of the back-side conductor layer 23. Therefore, when the mounting surface 23a of the back-side conductor layer 23 is joined to the surface 30a of the heat sink 30, the insulating substrate 21 does not come into contact with the positioning protrusion 31.

[0041] Such positioning protrusions 31 are provided along the mounting area Ra of the power device 20 on the surface 30a of the heat sink 30. More specifically, the positioning protrusions 31 are located outside the mounting area Ra and are provided adjacent to and along the edge of the mounting area Ra when viewed from the stacking direction.

[0042] In this embodiment, the positioning protrusions 31 are not provided along the entire edge of the mounting area Ra, but are provided along part of the edge of the mounting area Ra. In this embodiment, the mounting area Ra is rectangular. The positioning protrusions 31 are provided at each corner of one mounting area Ra. In other words, in this embodiment, four positioning protrusions 31 are provided for one mounting area Ra. Furthermore, each positioning protrusion 31 is formed in an L-shape so as to be bent at a right angle when viewed from the stacking direction.

[0043] In this embodiment, three mounting areas Ra are linearly arranged on the surface 30a of the heat sink 30. Four positioning protrusions 31 are provided for each mounting area Ra. Note that the positioning protrusions 31 provided for adjacent positioning protrusions 31 may be integrated with each other.

[0044] Such positioning protrusions 31 serve as marks when placing the power devices 20 on the heat sink 30 during the manufacturing process of the power conversion device 1. Furthermore, the positioning protrusions 31 prevent the power devices 20 from protruding from the mounting area Ra during the reflow process when the solder 50 is molten. By providing such positioning protrusions 31 on the surface 30a of the heat sink 30, the power devices 20 can be placed during the reflow process without using a jig.

[0045] The grooves 32 are formed along the edge of the positioning protrusions 31 on the mounting area Ra side. The grooves 32 are formed so as to be recessed from the surface 30a of the heat sink 30. Like the positioning protrusions 31, the grooves 32 are provided at each corner of one mounting area Ra. That is, in this embodiment, four grooves 32 are provided for one mounting area Ra. Furthermore, each groove 32 is formed in an L-shape so as to be bent at a right angle when viewed from the stacking direction. In this way, like the positioning protrusions 31, the grooves 32 are also provided at part of the edge of the mounting area Ra.

[0046] Such grooves 32 are formed by removing a portion of the heat sink 30 in order to prevent a fillet from occurring at the boundary between the positioning protrusion 31 and the surface 30a of the heat sink 30. In other words, the grooves 32 prevent a fillet from occurring at the boundary between the positioning protrusion 31 and the surface 30a of the heat sink 30.

[0047] 5 is a schematic diagram of one positioning protrusion 31 and one groove 32 as viewed from the stacking direction. As shown in this figure, each groove 32 has an end 32 a that protrudes outward beyond the positioning protrusion 31 as viewed from the stacking direction.

[0048] That is, the total length of each groove 32 is longer than the total length of the positioning protrusion 31. In this way, by providing the end 32 a of the groove 32 to protrude beyond the positioning protrusion 31, it is possible to more reliably prevent the above-mentioned fillet from occurring in the mounting area Ra.

[0049] When viewed from the stacking direction, the mounting surface 23a of the power device 20 is positioned so as to overlap a portion of the groove 32. Therefore, the edge of the mounting surface 23a is positioned very close to the positioning protrusion 31. If the groove 32 were positioned outside the mounting surface 23a, the area surrounded by the multiple grooves 32 would be wider, and the area surrounded by the multiple positioning protrusions 31 would be even wider.

[0050] In contrast, in this embodiment, the mounting surface 23a is positioned so as to overlap a portion of the groove 32, so the area surrounded by the positioning protrusion 31 can be made smaller, and the power device 20 can be positioned more accurately.

[0051] Furthermore, when viewed from the stacking direction, the edge 21a of the insulating substrate 21 of the power device 20 is positioned so as to overlap the positioning protrusion 31. Therefore, the edge of the mounting surface 23a and the positioning protrusion 31 are positioned very close to each other. If the positioning protrusion 31 were positioned outside the insulating substrate 21, the area surrounded by the multiple positioning protrusions 31 would be wider.

[0052] In contrast, in this embodiment, the edge 21a of the insulating substrate 21 is positioned so as to overlap the positioning protrusion 31, so that the area surrounded by the positioning protrusion 31 can be made smaller, and the power device 20 can be positioned more accurately.

[0053] The power device 20 mounted on the surface 30a of the heat sink 30 is sealed with a sealant (not shown). The sealant is provided so as to fill an opening provided in the module case 10, for example.

[0054] 6 is a flowchart showing a part of the manufacturing process of the power module 3a of this embodiment. As shown in this figure, the manufacturing process of the power module 3a of this embodiment includes a power device arrangement step S1 (semiconductor substrate arrangement step), a reflow step S2 (heating step), a case attachment step S3 (housing attachment step), and an ultrasonic bonding step S4.

[0055] First, in a power device placement step S1, the power device 20 is placed on the surface 30a of the heat sink 30. Here, the power device 20 is placed in a mounting area Ra surrounded by positioning protrusions 31 provided on the heat sink 30. Note that a solder sheet, for example, is placed between the heat sink 30 and the power device 20.

[0056] Next, in a reflow process S2, the heat sink 30 on which the power device 20 is placed is heated, thereby melting the solder sheet. After that, the heat sink 30 is cooled to form solder 50, and the power device 20 and the heat sink 30 are joined together.

[0057] Subsequently, in a case mounting step S3, the module case 10 with the bus bars 40 molded therein is mounted to the heat sink 30. The module case 10 is adhered to the surface 30a of the heat sink 30 via an adhesive.

[0058] In this manner, in this embodiment, the module case 10 is attached to the heat sink 30 after the reflow process S2. Therefore, the module case 10 is not exposed to the high-temperature environment in the reflow process S2.

[0059] Next, in an ultrasonic bonding process S4, the end of the bus bar 40 molded into the bus bar 40 is ultrasonically bonded to the power device 20. For example, the connection terminal 41b (end) of the bus bar 41 is placed over the terminal of the power device 20, and an ultrasonically vibrating tool is pressed against the connection terminal 41b to apply ultrasonic vibrations, thereby bonding the connection terminal 41b to the terminal of the power device 20.

[0060] Furthermore, the connection terminal 42b (end) of the bus bar 42 is placed over the terminal of the power device 20, and an ultrasonically vibrating tool is pressed against the connection terminal 42b to apply ultrasonic vibrations, thereby joining the connection terminal 42b to the terminal of the power device 20. By using such ultrasonic joining, the end of the bus bar 40 and the power device 20 are joined by atomic force.

[0061] After joining the bus bar 40 and the power device 20 in this manner, a sealant is formed as needed to form the power module 3 a. The power conversion device 1 is manufactured using such a power module 3 a.

[0062] The power module 3a included in the power conversion device 1 of this embodiment as described above includes a heat sink 30, power devices 20, and a module case 10. The power devices 20 are mounted on a surface 30a of the heat sink 30. The module case 10 is fixed to the surface 30a of the heat sink 30 so as to surround the power devices 20. The heat sink 30 also includes a positioning protrusion 31 and a groove 32. The positioning protrusion 31 is provided along the mounting area Ra of the power devices 20 and is formed to protrude from the surface 30a of the heat sink 30. The groove 32 is formed along the edge of the positioning protrusion 31 on the mounting area Ra side and is formed to be recessed from the surface 30a of the heat sink 30.

[0063] The power module 3a of this embodiment is provided with positioning protrusions 31 that are aligned with the mounting area Ra of the heat sink 30. Therefore, the power devices 20 can be positioned on the heat sink 30 using the positioning protrusions 31 as guide marks, and the power devices 20 can be positioned on the heat sink 30 without using a jig. Furthermore, grooves 32 are provided on the edges of the positioning protrusions 31 on the mounting area Ra side. Therefore, in the power module 3a of this embodiment, no fillets are formed at the boundaries between the positioning protrusions 31 and the surface 30a of the heat sink 30, and the power devices 20 can be prevented from climbing up onto the fillets and becoming tilted. Therefore, in the power module 3a of this embodiment, in which the power devices 20 are mounted on the heat sink 30, the power devices 20 can be accurately positioned on the heat sink 30 without using a jig.

[0064] Furthermore, in the power module 3a of this embodiment, the mounting surface 23a of the power device 20 is positioned so as to overlap part of the groove 32 when viewed from the stacking direction of the heat sink 30 and the power device 20. In the power module 3a of this embodiment, the area surrounded by the positioning protrusions 31 can be made smaller, and the power device 20 can be positioned more accurately.

[0065] Furthermore, in the power module 3a of this embodiment, the power device 20 includes a sheet-like insulating substrate 21, a top-side conductor layer 22, and a bottom-side conductor layer 23. The top-side conductor layer 22 is formed on one surface of the insulating substrate 21. The bottom-side conductor layer 23 is formed on the other surface of the insulating substrate 21 so that an edge portion 21a of the insulating substrate 21 is exposed. The surface of the bottom-side conductor layer 23 opposite the insulating substrate 21 is a mounting surface 23a. The protrusion dimension of the positioning protrusion 31 from the surface 30a of the heat sink 30 is greater than the thickness dimension of the bottom-side conductor layer 23.

[0066] The power module 3 a in this embodiment can prevent the insulating substrate 21 from coming into contact with the positioning protrusions 31. Therefore, for example, during a reflow process, the insulating substrate 21 can be prevented from coming into contact with the positioning protrusions 31, thereby preventing the power device 20 from tilting.

[0067] Furthermore, in the power module 3a of this embodiment, the edge portion 21a of the insulating substrate 21 is positioned so as to overlap at least a portion of the positioning protrusion 31 when viewed from the stacking direction of the heat sink 30 and the power device 20. In the power module 3a of this embodiment, the area surrounded by the positioning protrusion 31 can be made smaller, and the power device 20 can be positioned more accurately.

[0068] The power module 3a in this embodiment includes bus bars 40 joined to the power devices 20 by atomic force. In the power module 3a in this embodiment, the bus bars 40 do not need to be soldered to the power devices 20. This eliminates the need to expose the power module 3a to a high-temperature environment.

[0069] In the power module 3a of this embodiment, the middle portion of the bus bar 40 is molded into the module case 10. The end portion of the bus bar 40 is exposed from the module case 10. In the power module 3a of this embodiment, the end portion of the bus bar 40 can be positioned relative to the power device 20 by fixing the module case 10 to the heat sink 30. Therefore, there is no need to position the bus bar 40 using a jig or the like.

[0070] Furthermore, in the power module 3a of this embodiment, the positioning protrusions 31 and the grooves 32 are provided on part of the edge of the mounting area Ra. Therefore, in the power module 3a of this embodiment, the positioning protrusions 31 and the grooves 32 can be shorter than in a case where the positioning protrusions 31 and the grooves 32 are provided on the entire edge of the mounting area Ra. Therefore, in the power module 3a of this embodiment, the range of the heat sink 30 that requires micromachining can be kept to a minimum.

[0071] In the power module 3a of this embodiment, the grooves 32 are provided so that their ends protrude beyond the positioning protrusions 31 when viewed in the stacking direction of the heat sink 30 and the power devices 20. The power module 3a of this embodiment can more reliably prevent the above-mentioned fillets from occurring in the mounting area Ra, and can more reliably suppress tilting of the power devices 20.

[0072] The power conversion device 1 of this embodiment includes the power module 3a described above and has a power conversion circuit H at least a portion of which is formed by the power devices 20. The power conversion device 1 of this embodiment can accurately position the power devices 20 relative to the heat sink 30 without using a jig.

[0073] The manufacturing method of the power module 3a in this embodiment includes a power device placement step S1 in which the power devices 20 are placed on the surface 30a of the heat sink 30, and a reflow step S2 in which the heat sink 30 on which the power devices 20 are placed is heated. The heat sink 30 includes a positioning protrusion 31 and a groove 32. The positioning protrusion 31 is provided along the mounting area Ra of the power devices 20 and is formed to protrude from the surface 30a of the heat sink 30. The groove 32 is formed along the edge of the positioning protrusion 31 on the mounting area Ra side and is formed to be recessed from the surface 30a of the heat sink 30. The manufacturing method of the power module 3a in this embodiment also includes a power device placement step in which the power devices 20 are placed in the mounting area Ra.

[0074] In the manufacturing method of the power module 3a according to this embodiment, the power devices 20 can be positioned on the heat sink 30 using the positioning protrusions 31 as guide marks, and the power devices 20 can be positioned on the heat sink 30 without using a jig. Furthermore, the grooves 32 are provided on the edges of the positioning protrusions 31 on the mounting area Ra side, which prevents the power devices 20 from climbing up onto the fillet and becoming tilted. Therefore, the manufacturing method of the power module 3a according to this embodiment allows the power devices 20 to be accurately positioned on the heat sink 30 without using a jig.

[0075] The method for manufacturing the power module 3a in this embodiment also includes a case mounting step S3 that is performed after the reflow step S2. In the case mounting step S3, the module case 10 is fixed to the surface 30a of the heat sink 30 so as to surround the power device 20.

[0076] In the method for manufacturing the power module 3a in this embodiment, the module case 10 is fixed to the heat sink 30 after the reflow process S2. Therefore, the module case 10 is not exposed to the high-temperature environment of the reflow process S2.

[0077] In the manufacturing method of the power module 3a in this embodiment, the module case 10 molds the middle portions of the bus bars 40 so as to expose the ends of the bus bars 40. Furthermore, the manufacturing method of the power module 3a in this embodiment includes, after the case mounting step, an ultrasonic bonding step of bonding the ends of the bus bars 40 to the power devices 20 by ultrasonic bonding.

[0078] The method for manufacturing the power module 3a of this embodiment can join the ends of the bus bars 40 to the power devices 20 without exposing the module case 10 to a high-temperature environment.

[0079] While the preferred embodiments of the present invention have been described above with reference to the accompanying drawings, it goes without saying that the present invention is not limited to the above-described embodiments. The shapes and combinations of the components shown in the above-described embodiments are merely examples, and various modifications can be made based on design requirements, etc., without departing from the spirit of the present invention.

[0080] 7, the solder 50 may fill the groove 32 and contact the side surface of the back-side conductor layer 23. By providing the solder 50 as shown in Fig. 7, the contact area between the solder 50 and the back-side conductor layer 23 and the contact area between the solder 50 and the heat sink 30 can be increased, and the bonding strength between the power device 20 and the heat sink 30 can be improved.

[0081] In the above embodiment, the semiconductor device is a power module 3a. However, the present invention is not limited to this. The present invention can be applied to a semiconductor device in which a semiconductor substrate is mounted on a base member and a housing is provided on the base member that surrounds the semiconductor substrate.

[0082] The above embodiment can also be described as follows, for example:

[0083] (Supplementary Note 1) A semiconductor device comprising: a base member; a semiconductor substrate mounted on a surface of the base member; and a housing fixed to the surface of the base member so as to surround the semiconductor substrate, wherein the base member has a protrusion provided along a mounting area of ​​the semiconductor substrate and formed to protrude from the surface of the base member; and a groove formed along an edge of the protrusion on the mounting area side and formed to be recessed from the surface of the base member.

[0084] (Supplementary Note 2) The semiconductor device according to Supplementary Note 1, wherein the mounting surface of the semiconductor substrate is positioned so as to overlap a part of the groove when viewed from the stacking direction of the base member and the semiconductor substrate.

[0085] (Appendix 3) The semiconductor substrate comprises a sheet-like insulating base material, a front conductor layer formed on one surface of the insulating base material, and a back conductor layer formed on the other surface of the insulating base material so that an edge of the insulating base material is exposed, the surface of the back conductor layer opposite the insulating base material is a mounting surface, and the protrusion has a protrusion dimension from the surface of the base member that is greater than a thickness dimension of the back conductor layer.

[0086] (Supplementary Note 4) The semiconductor device according to Supplementary Note 3, wherein an edge of the insulating base material is positioned so as to overlap at least a portion of the protrusion when viewed from the stacking direction of the base member and the semiconductor substrate.

[0087] (Supplementary Note 5) The semiconductor device according to any one of Supplementary Notes 1 to 4, further comprising a conductive member bonded to the semiconductor substrate by atomic force.

[0088] (Supplementary Note 6) The semiconductor device according to Supplementary Note 5, wherein the conductive member has a middle portion molded into the housing and an end portion exposed from the housing.

[0089] (Supplementary Note 7) The semiconductor device according to any one of Supplementary Notes 1 to 6, wherein the protrusion and the groove are provided on a part of an edge of the mounting area.

[0090] (Supplementary Note 8) The semiconductor device according to Supplementary Note 7, wherein the groove portion has an end portion projecting beyond the protrusion portion when viewed from the stacking direction of the base member and the semiconductor substrate.

[0091] (Supplementary Note 9) A power conversion device comprising the semiconductor device according to any one of Supplementary Notes 1 to 7, and a power conversion circuit at least part of which is formed by the semiconductor substrate.

[0092] (Appendix 10) A method for manufacturing a semiconductor device, comprising: a semiconductor substrate placement step of placing a semiconductor substrate on a surface of a base member; and a heating step of heating the base member on which the semiconductor substrate is placed, wherein the base member has: a protrusion that is provided along a mounting area of ​​the semiconductor substrate and that protrudes from the surface of the base member; and a groove that is formed along an edge of the protrusion on the mounting area side and that is recessed from the surface of the base member; and wherein the semiconductor substrate placement step places the semiconductor substrate on the mounting area.

[0093] (Appendix 11) The method for manufacturing a semiconductor device according to appendix 10, further comprising a housing mounting step performed after the heating step, wherein in the housing mounting step, a housing is fixed to the surface of the base member so as to surround the semiconductor substrate.

[0094] (Appendix 12) The method for manufacturing a semiconductor device according to Appendix 11, wherein the housing molds an intermediate portion of the conductive member so as to expose an end portion of the conductive member, and the method includes an ultrasonic bonding process for bonding the end portion of the conductive member to the semiconductor substrate by ultrasonic bonding after the housing mounting process.

[0095] REFERENCE SIGNS LIST 1 Power conversion device 2 Inverter case 3 Intelligent power module 3a Power module (semiconductor device) 4 Capacitor unit 10 Module case (housing) 20 Power device (semiconductor substrate) 21 Insulating substrate 21a Edge 22 Front conductor layer 23 Back conductor layer 23a Mounting surface 24 Semiconductor element 30 Heat sink (base member) 30a Surface 31 Positioning protrusion (protrusion) 32 Groove 32a End 40 Bus bar (conductive member) 41 Bus bar (conductive member) 41a Connection terminal (end) 41b Connection terminal (end) 42 Bus bar (conductive member) 42a Connection terminal (end) 42b Connection terminal (end) B Battery H Power conversion circuit M Motor Ra Mounting area

Claims

1. A semiconductor device comprising: a base member; a semiconductor substrate mounted on a surface of the base member; and a housing fixed to the surface of the base member so as to surround the semiconductor substrate, wherein the base member has a protrusion disposed along a mounting area of ​​the semiconductor substrate and protruding from the surface of the base member; and a groove formed along an edge of the protrusion facing the mounting area and recessed from the surface of the base member.

2. The semiconductor device according to claim 1, wherein the mounting surface of said semiconductor substrate is positioned so as to overlap a portion of said groove when viewed in the lamination direction of said base member and said semiconductor substrate.

3. The semiconductor substrate comprises a sheet-like insulating base material, a front conductor layer formed on one surface of the insulating base material, and a back conductor layer formed on the other surface of the insulating base material so as to expose an edge of the insulating base material, the surface of the back conductor layer opposite the insulating base material being a mounting surface, and the protrusion dimension of the protrusion from the surface of the base member is greater than the thickness dimension of the back conductor layer.

4. The semiconductor device according to claim 3, wherein an edge of said insulating base material is positioned so as to overlap at least a portion of said protrusion when viewed in the lamination direction of said base member and said semiconductor substrate.

5. The semiconductor device according to claim 1 or 2, further comprising a conductive member bonded to said semiconductor substrate by atomic force.

6. The semiconductor device according to claim 5, wherein the conductive member has a middle portion molded into the case and an end portion exposed from the case.

7. The semiconductor device according to claim 1 or 2, wherein the protrusion and the groove are provided on a part of an edge of the mounting area.

8. The semiconductor device according to claim 7, wherein an end of said groove portion is provided so as to protrude beyond said protrusion portion when viewed in the lamination direction of said base member and said semiconductor substrate.

9. A power conversion device comprising the semiconductor device according to claim 1 or 2, and a power conversion circuit at least a part of which is formed by the semiconductor substrate.

10. A method for manufacturing a semiconductor device comprising a semiconductor substrate positioning step of positioning a semiconductor substrate on a surface of a base member, and a heating step of heating the base member on which the semiconductor substrate is positioned, wherein the base member has a protrusion that is provided along the mounting area of ​​the semiconductor substrate and that protrudes from the surface of the base member, and a groove that is formed along the edge of the protrusion on the mounting area side and that is recessed from the surface of the base member, and wherein the semiconductor substrate positioning step positions the semiconductor substrate in the mounting area.

11. The method for manufacturing a semiconductor device according to claim 10, further comprising a housing mounting step carried out after the heating step, wherein a housing is fixed to the surface of the base member so as to surround the semiconductor substrate in the housing mounting step.

12. The method for manufacturing a semiconductor device according to claim 11, characterized in that the housing has a molded middle portion of the conductive member so as to expose the end portion of the conductive member, and after the housing mounting process, an ultrasonic bonding process is performed to bond the end portion of the conductive member to the semiconductor substrate by ultrasonic bonding.

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