Semiconductor device and power conversion device

Abstract

To provide a semiconductor device that ensures bonding reliability of a wiring board.SOLUTION: The semiconductor device 101 includes: an insulating substrate 10 having a circuit layer 12 formed on an upper surface thereof; a semiconductor element 20 joined onto the circuit layer 12 of the insulating substrate 10 through a first conductive bonding material 31, the semiconductor element 20 having an electrode layer 21 formed on its upper surface; a conductor 40 joined to at least one of the circuit layer 12 of the insulating substrate 10 and the electrode layer 21 of the semiconductor element 20 through a second conductive bonding material 32; and a wiring board 50 welded to the conductor 40. The second conductive bonding material 32 has a fillet shape 32f covering a side surface of the conductor 40.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] In recent years, semiconductor devices using plate-shaped wiring boards have been increasing in number in order to reduce the space required for internal wiring in semiconductor devices, etc. Furthermore, as a method for joining wiring boards, a method has been proposed in which a wiring board is joined by laser welding to a circuit layer formed on an insulating substrate or to an electrode layer formed on a semiconductor element.

[0003] Joining wiring boards by laser welding may destroy the insulating layer of the insulating substrate or the element structure of the semiconductor element, depending on the penetration depth during laser welding. Therefore, as a countermeasure for laser welding, for example, Patent Document 1 discloses a technology in which a conductor (metal plate) is soldered onto the circuit layer of the insulating substrate, and the conductor and the wiring board (external terminal) are laser-welded to prevent the weld from reaching the insulating layer, thereby suppressing destruction of the insulating layer of the insulating substrate. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-205058 Summary of the Invention [Problem to be solved by the invention]

[0005] However, because semiconductor devices are multilayer structures made up of multiple different materials, stress occurs due to differences in the thermal expansion coefficients of the materials as the temperature changes during operation of the semiconductor device. In the device of Patent Document 1, as the temperature changes during operation of the semiconductor device, stress concentrates on the solder that connects the insulating substrate and the conductor, causing cracks to form and grow in the solder, which can make it difficult to ensure the reliability of the joint. In other words, the device of Patent Document 1 has a problem in that temperature changes during operation of the semiconductor device make it difficult to ensure the joint reliability of the wiring board.

[0006] The present disclosure has been made to solve the above-mentioned problems, and has an object to provide a semiconductor device and a power conversion device that ensure the bonding reliability of wiring boards. [Means for solving the problem]

[0007] The semiconductor device according to the present disclosure comprises an insulating substrate having a circuit layer formed on its upper surface, a semiconductor element bonded to the circuit layer of the insulating substrate via a first conductive adhesive and having an electrode layer formed on its upper surface, a conductor bonded to at least one of the circuit layer of the insulating substrate and the electrode layer of the semiconductor element via a second conductive adhesive, and a wiring board welded to the conductor, wherein the second conductive adhesive has a fillet shape that covers a portion of the side surface of the conductor.

[0008] The power conversion device according to the present disclosure includes a main conversion circuit that has a semiconductor device according to the present disclosure and converts and outputs input power, and a control circuit that outputs a control signal to the main conversion circuit to control the main conversion circuit. [Effects of the Invention]

[0009] According to the semiconductor device and power conversion device according to the present disclosure, the bonding reliability of the wiring board can be ensured. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a schematic diagram illustrating a structure of a semiconductor device according to a first embodiment of the present disclosure. [Figure 2]1A to 1C are schematic diagrams illustrating a method for manufacturing a semiconductor device according to a first embodiment of the present disclosure. [Figure 3] 1 is a schematic cross-sectional view showing a structure of a semiconductor device according to a first modification of the first embodiment of the present disclosure. [Figure 4] 10 is a schematic cross-sectional view showing a structure of a semiconductor device according to a second modification of the first embodiment of the present disclosure. FIG. [Figure 5] FIG. 10 is a schematic diagram illustrating a structure of a semiconductor device according to a second embodiment of the present disclosure. [Figure 6] 10A to 10C are schematic diagrams illustrating a method for manufacturing a semiconductor device according to a second embodiment of the present disclosure. [Figure 7] FIG. 10 is a schematic diagram illustrating a structure of a semiconductor device according to a third embodiment of the present disclosure. [Figure 8] FIG. 10 is a block diagram showing a configuration of a power conversion system to which a power conversion device according to a fourth embodiment of the present disclosure is applied. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, an example of a semiconductor device and a power conversion device according to the present disclosure will be described with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference numerals, and the description thereof will not be repeated. The XYZ Cartesian coordinate system is defined so that the Z direction is the vertical direction and the XY plane is the horizontal plane. When positive or negative signs are assigned to directions, the +X, +Y, and +Z directions refer to the arrow directions of the Cartesian coordinate system shown in each figure, and the +Z direction will be described below as the upward direction. Furthermore, in the following description, the length of each component may be described as the width in the Y direction and the thickness in the Z direction.

[0012] Embodiment 1 <Configuration of First Embodiment> The configuration of a semiconductor device 101 according to a first embodiment of the present disclosure will be described with reference to FIG. 1. FIG. 1 is a schematic diagram showing the structure of the semiconductor device 101, where FIG. 1(a) is a schematic top view, FIG. 1(b) is a schematic cross-sectional view taken along line AA in FIG. 1(a), and FIG. 1(c) is an enlarged view of a main portion. Note that, for ease of viewing, FIG. 1(a) omits the sealing resin 63 and indicates the wiring board 50 with a dotted line. Also, for ease of viewing, FIG. 1(c) shows the wiring board 50 in a state prior to assembly.

[0013] As shown in FIG. 1, the semiconductor device 101 includes, inside a case 60, an insulating substrate 10, a semiconductor element 20 bonded onto the insulating substrate 10, a conductor 40 bonded onto the insulating substrate 10 and the semiconductor element 20, a wiring board 50 welded to the conductor 40, a wire 62 electrically connecting the semiconductor element 20 and a signal terminal 61, and a sealing resin 63 that seals the internal structure of the case 60.

[0014] The insulating substrate 10 is composed of an insulating layer 11 arranged parallel to the XY plane, a circuit layer 12 formed on the upper surface of the insulating layer 11, and a lower conductor layer 13 formed on the lower surface of the insulating layer 11. The insulating layer 11 is made of, for example, a nitride ceramic such as silicon nitride or aluminum nitride, or an oxide ceramic such as alumina. The circuit layer 12 and the lower conductor layer 13 are made of, for example, copper. The thickness of each layer of the insulating substrate 10 is, for example, 0.32 mm for the insulating layer 11, and 0.8 mm for the circuit layer 12 and the lower conductor layer 13. The length of each layer of the insulating substrate 10 in the X direction is, for example, 65 mm, and the length of each layer of the insulating substrate 10 in the Y direction is, for example, 60 mm.

[0015] The semiconductor element 20 is bonded onto the circuit layer 12 formed on the insulating substrate 10 via a first conductive bonding material 31. In other words, the lower surface of the semiconductor element 20 is bonded to the circuit layer 12 of the insulating substrate 10 via the first conductive bonding material 31.

[0016] The first conductive bonding material 31 is, for example, a solder material. The first conductive bonding material 31 bonds the circuit layer 12 of the insulating substrate 10 to the semiconductor element 20, and electrically connects the circuit layer 12 to the semiconductor element 20. The solder material used as the first conductive bonding material 31 may be, for example, a SnAgCu-based material, a SnCu-based material, or a SnSb-based material. The first conductive bonding material 31 may also be a brazing material or a silver sintered material.

[0017] The first conductive bonding material 31 has a fillet shape that covers the side surface of the semiconductor element 20. In other words, the first conductive bonding material 31 forms a shape that is gently inclined and flared from the side surface of the semiconductor element 20 to the circuit layer 12 of the insulating substrate 10.

[0018] The first conductive bonding material 31, which is the bonding portion between the circuit layer 12 of the insulating substrate 10 and the semiconductor element 20, has a larger area than a bonding portion without a fillet shape, i.e., a bonding portion provided only between the circuit layer 12 of the insulating substrate 10 and the underside of the semiconductor element 20. Therefore, when stress occurs due to the difference in thermal expansion coefficients between the insulating substrate 10 and the semiconductor element 20 as the temperature changes during operation of the semiconductor device 101, the first conductive bonding material 31 distributes the applied stress over a larger area than a bonding portion without a fillet shape. Furthermore, the fillet shape of the first conductive bonding material 31 has a gentle shape and few corners at which stress concentrates, so the stress applied to the first conductive bonding material 31 is distributed evenly. Therefore, even when stress is applied to the first conductive bonding material 31, the first conductive bonding material 31 distributes the stress and is less likely to break due to stress concentration. Note that the fillet shape of the first conductive bonding material 31 is preferably formed around the entire circumference of the semiconductor element 20.

[0019] The semiconductor elements 20 are, for example, a diode 20a which is a power semiconductor element, and an IGBT (Insulated Gate Bipolar Transistor) 20b which is a control semiconductor element. The substrate of the diode 20a and the IGBT 20b is, for example, silicon. The thickness of the diode 20a and the IGBT 20b is, for example, 0.2 mm. The diode 20a is, for example, 10 mm long in the X direction and 8 mm long in the Y direction. The IGBT 20b is, for example, 10 mm long in the X direction and 10 mm long in the Y direction. In the following description, when there is no need to distinguish between the diode 20a and the IGBT 20b, the diode 20a and the IGBT 20b will be collectively referred to as the semiconductor elements 20.

[0020] An electrode layer 21 is formed on the upper surface of the semiconductor element 20 opposite to the lower surface bonded to the insulating substrate 10. Specifically, an electrode layer 21a is formed on the upper surface of the diode 20a, and an electrode layer 21b is formed on the upper surface of the IGBT 20b. In the following description, when the electrode layer 21a and the electrode layer 21b are not distinguished from each other, the electrode layer 21a and the electrode layer 21b will be collectively referred to as the electrode layer 21. The electrode layer 21 may be provided in one location on the upper surface of one semiconductor element 20, or in two or more locations. The electrode layer 21 is made of, for example, an aluminum alloy. The electrode layer 21 has a length of, for example, 8 mm in the X direction and 6 mm in the Y direction.

[0021] A metal film is formed on the surface of the electrode layer 21 to improve bonding with the second conductive bonding material 32. The material of the metal film formed on the surface of the electrode layer 21 is, for example, nickel, gold, titanium, or the like.

[0022] Furthermore, a signal electrode 22 is formed on the top surface of the IGBT 20b in addition to the electrode layer 21b. The signal electrode 22 may be provided in one location or in two or more locations on the top surface of one IGBT 20b. The signal electrode 22 is made of, for example, an aluminum alloy.

[0023] Electrical conductors 40 are bonded onto the circuit layer 12 formed on the insulating substrate 10 and onto each electrode layer 21 formed on each semiconductor element 20 via a second conductive bonding material 32. Here, of the electrical conductors 40, the electrical conductor 40 bonded onto the circuit layer 12 of the insulating substrate 10 is referred to as a first electrical conductor 40a, and the electrical conductor 40 bonded onto the electrode layer 21 of the semiconductor element 20 is referred to as a second electrical conductor 40b. In other words, the lower surface of the first electrical conductor 40a is bonded to the circuit layer 12 of the insulating substrate 10 via the second conductive bonding material 32, and the lower surface of the second electrical conductor 40b is bonded to the electrode layer 21 of the semiconductor element 20 via the second conductive bonding material 32. The first electrical conductor 40a is bonded onto a region of the circuit layer 12 of the insulating substrate 10 to which the semiconductor element 20 is not bonded. In the following description, when there is no need to distinguish between the first conductor 40a and the second conductor 40b, the first conductor 40a and the second conductor 40b will be collectively referred to as conductor 40.

[0024] The second conductive bonding material 32 is, for example, a solder material. The second conductive bonding material 32 bonds the circuit layer 12 of the insulating substrate 10 and the electrode layer 21 of the semiconductor element 20 to the conductor 40, and electrically connects the circuit layer 12 and the electrode layer 21 to the conductor 40. The solder material used as the second conductive bonding material 32 may be, for example, a SnAgCu-based material, a SnCu-based material, or a SnSb-based material. The second conductive bonding material 32 may also be a brazing material or a silver sintered material.

[0025] 1(c), the second conductive bonding material 32 has a fillet shape 32f that covers the side surface of the conductor 40. In detail, the second conductive bonding material 32 that bonds the first conductor 40a and the circuit layer 12 of the insulating substrate 10 forms a shape that is gently sloping and flared from the side surface of the conductor 40 to the circuit layer 12 of the insulating substrate 10. The second conductive bonding material 32 that bonds the second conductor 40b and the electrode layer 21 of the semiconductor element 20 forms a shape that is gently sloping and flared from the side surface of the conductor 40 to the electrode layer 21 of the semiconductor element 20.

[0026] The second conductive bonding material 32, which is the bonding portion between the circuit layer 12 of the insulating substrate 10 and the semiconductor element 20, has a larger area than a bonding portion without the fillet shape 32f, i.e., a bonding portion provided only between the circuit layer 12 of the insulating substrate 10 and the underside of the semiconductor element 20. Therefore, when stress occurs due to the difference in thermal expansion coefficients between the insulating substrate 10 and the semiconductor element 20 as the temperature changes during operation of the semiconductor device 101, the second conductive bonding material 32 distributes the applied stress over a larger area than a bonding portion without the fillet shape 32f. Furthermore, the fillet shape 32f of the second conductive bonding material 32 has a gentle shape and few corners at which stress concentrates, so that the stress applied to the second conductive bonding material 32 is distributed uniformly. Therefore, even when stress is applied to the second conductive bonding material 32, the second conductive bonding material 32 distributes the stress and is less likely to break due to stress concentration. It is preferable that the fillet shape 32f of the second conductive bonding material 32 is formed around the entire circumference of the conductor 40.

[0027] Furthermore, it is desirable that the area of ​​the lower surface of the second conductor 40b bonded to the electrode layer 21 of the semiconductor element 20 is smaller than the area of ​​the electrode layer 21 of the semiconductor element 20, and that the second conductive bonding material 32 bonding the electrode layer 21 of the semiconductor element 20 and the second conductor 40b cover the entire surface of the electrode layer 21. The portion of the electrode layer 21 covered by the second conductive bonding material 32 is the portion that electrically connects to the conductor 40, i.e., the portion used as a circuit. Therefore, by having the second conductive bonding material 32 cover the entire surface of the electrode layer 21, the entire surface of the electrode layer 21 can be used as a circuit, thereby achieving high signal transmission efficiency. Furthermore, when the second conductive bonding material 32 covers the entire surface of the electrode layer 21, the area of ​​the second conductive bonding material 32 is larger than when the second conductive bonding material 32 covers only a portion of the electrode layer 21, thereby achieving mechanically stable bonding.

[0028] Conductor 40 is made of a conductive metal and is provided between insulating substrate 10 and wiring board 50, and between semiconductor element 20 and wiring board 50. The material of conductor 40 is, for example, copper, nickel, or the like.

[0029] As shown in FIG. 1(c), the conductor 40 has a convex portion 42 that protrudes upward from an upper surface 41 opposite to the lower surface bonded to the insulating substrate 10 or the semiconductor element 20. Here, the portion of the conductor 40 that has the lower surface bonded to the insulating substrate 10 and the semiconductor element 20 and the upper surface 41 from which the convex portion 42 protrudes is referred to as a bottom portion 43. That is, the conductor 40 is composed of the bottom portion 43 and the convex portion 42 that protrudes from the upper surface 41 of the bottom portion 43. Here, the upper surface 41 of the conductor 40 and the upper surface 41 of the bottom portion 43 represent the same surface.

[0030] 1, the bottom 43 and the protrusions 42 of the conductor 40 are formed, for example, in a cylindrical shape. For example, the bottom 43 of the conductor 40 is cylindrical with a diameter of 5 mm and a thickness of 1 mm, and the protrusions 42 of the conductor 40 are cylindrical with a diameter of 2.5 mm and a thickness of 3 mm. 1 shows an example in which the bottom 43 and the protrusions 42 of the conductor 40 are formed in a cylindrical shape, but the shape of the conductor 40 is not limited to this. The shape of the conductor 40 may be any shape as long as the area of ​​the top surface of the bottom 43 is larger than the area of ​​the surface of the protrusions 42 perpendicular to the protruding direction of the protrusions 42 of the conductor 40. For example, the bottom 43 and the protrusions 42 of the conductor 40 may be in the shape of a quadrangular prism. Furthermore, the bottom 43 of the conductor 40 and the protrusions 42 of the conductor 40 may have different shapes.

[0031] A wiring board 50 is welded to the conductor 40. The wiring board 50 is a plate-shaped member formed, for example, by press working. A portion of the wiring board 50 is integrated with the case 60, with one end inside the case 60 and the other end outside the case 60. One end of the wiring board 50 is provided inside the case 60, with a portion of it arranged parallel to the insulating substrate 10 and the semiconductor element 20, and is used as a wiring member to be welded to the conductor 40. The other end of the wiring board 50 is exposed from the side surface of the case 60 and is used as a connection terminal for connecting to the outside. The wiring board 50 is made of, for example, copper. The wiring board 50 is, for example, 6 mm wide and 0.5 mm thick.

[0032] Wiring board 50 has opening 51 at one end provided inside case 60, into which protrusion 42 of conductor 40 is inserted. Protrusion 42 of conductor 40 is inserted into opening 51 of wiring board 50, and the side surface of protrusion 42 of conductor 40 is welded to the inner wall surface formed by opening 51 of wiring board 50. The diameter of opening 51 is, for example, 3 mm.

[0033] In a plane perpendicular to the direction in which convex portion 42 of conductor 40 protrudes, opening 51 of wiring board 50 has an area equivalent to that of convex portion 42 of conductor 40. Furthermore, the end of upper surface 41 of conductor 40 is formed so as to be positioned outside opening 51 of wiring board 50 when convex portion 42 of conductor 40 is inserted into opening 51 of wiring board 50. Therefore, when convex portion 42 of conductor 40 is inserted into wiring board 50, upper surface 41 of conductor 40 comes into contact with the lower surface of wiring board 50. This allows conductor 40 to function as a spacer that maintains a distance between insulating substrate 10 and wiring board 50, and between semiconductor element 20 and wiring board 50.

[0034] The case 60 is a peripheral wall that surrounds the outer periphery of the semiconductor element 20. The insulating substrate 10 is attached inside the case 60, and the upper surface of the insulating substrate 10 and the case 60 form a container. The case 60 is made of a thermoplastic resin such as PPS (polyphenylene sulfide) or PBT (polybutylene terephthalate). The case 60 has a length of 90 mm in the X direction, a length of 70 mm in the Y direction, and a length of 10 mm in the Z direction, for example.

[0035] A signal terminal 61 is insert-molded into the case 60. One end of the signal terminal 61 is provided inside the case 60 and the other end is provided outside the case 60. One end of the signal terminal 61 is used for electrical connection with the IGBT 20b. The other end of the signal terminal 61 is used as a connection terminal for connecting to the outside. The signal terminal 61 is made of a material such as copper, aluminum, or a composite material thereof. The signal terminal 61 is 1.5 mm wide and 0.6 mm thick.

[0036] One end of the signal terminal 61 is electrically connected to the IGBT 20b via a wire 62. Specifically, the wire 62 is provided between the signal electrode 22 formed on the upper surface of the IGBT 20b and the one end of the signal terminal 61. The wire 62 is made of, for example, aluminum, an aluminum alloy containing a small amount of additive such as iron, or copper. The diameter of the wire 62 is, for example, 0.15 mm. Note that a ribbon band made of aluminum, copper, or the like, or a copper lead frame may be used instead of the wire 62. The ribbon band or the lead frame is provided between the signal electrode 22 and one end of the signal terminal 61 by soldering.

[0037] The sealing resin 63 is filled into a container formed by the insulating substrate 10 and the case 60. The sealing resin 63 seals the circuit layer 12 of the insulating substrate 10, the semiconductor element 20, the conductors 40, part of the wiring board 50, the wires 62, the first conductive bonding material 31, and the second conductive bonding material 32 within the container. The length in the Z direction from the top surface of the insulating substrate 10 to the top surface of the sealing resin 63 is, for example, 8 mm.

[0038] The sealing resin 63 is made of a thermosetting resin such as epoxy resin, and may contain a powder (filler) such as silica as needed to adjust its mechanical properties. The sealing resin 63 protects each component from contamination and impact and ensures insulation. The sealing resin 63 also restrains the joints of each component, such as the joint between the insulating substrate 10 and the conductor 40, and the joint between the semiconductor element 20 and the conductor 40, thereby suppressing damage caused by stress resulting from differences in the thermal expansion coefficients of the insulating substrate 10 and the semiconductor element 20 on the one hand, and the conductor 40 on the other.

[0039] <Manufacturing Method of First Embodiment> Next, a method for manufacturing the semiconductor device 101 according to the first embodiment of the present disclosure will be described with reference to Fig. 2. Fig. 2 is a schematic diagram for explaining the method for manufacturing the semiconductor device 101. Note that in Fig. 2(c), the laser light is indicated by a dotted arrow, and the irradiation path of the laser light is indicated by a solid arrow.

[0040] As shown in FIG. 2( a), first, the insulating substrate 10, the semiconductor element 20, and the conductor 40 are positioned and mounted. At this time, a first conductive bonding material 31 is placed between the insulating substrate 10 and the semiconductor element 20, and a second conductive bonding material 32 is placed between the insulating substrate 10, the semiconductor element 20, and the conductor 40. Next, the positioned and mounted insulating substrate 10, the semiconductor element 20, and the conductor 40 are placed in an atmosphere at or above the melting points of the first conductive bonding material 31 and the second conductive bonding material 32, to melt the first conductive bonding material 31 and the second conductive bonding material 32. After the first conductive bonding material 31 and the second conductive bonding material 32 have melted, they are cooled, and the insulating substrate 10, the semiconductor element 20, and the conductor 40 are bonded together.

[0041] It is desirable that the second conductor 40b bonded onto the electrode layer 21 of the semiconductor element 20 is positioned and bonded at the center of the electrode layer 21. It is also desirable that the amount of second conductive bonding material 32 that bonds the second conductor 40b onto the electrode layer 21 of the semiconductor element 20 is sufficient to cover the entire surface of the electrode layer 21. By bonding the second conductor 40b onto the electrode layer 21 of the semiconductor element 20 via the second conductive bonding material 32 in an amount that covers the entire surface of the electrode layer 21, a fillet can be formed around the entire periphery of the second conductor 40b.

[0042] 2(b), a case 60 is attached to the bonded insulating substrate 10, semiconductor element 20 (diode 20a, IGBT 20b), and conductor 40. Here, the wiring board 50 and a portion of the signal terminal 61 are assembled to the case 60 so that they are integrated. When attaching the case 60, the attachment position of the case 60 is determined so that a container is formed by the upper surface of the insulating substrate 10 and the case 60, and the protrusion 42 of the conductor 40 is inserted into the opening 51 of the wiring board 50. Then, the insulating substrate 10 and the case 60 are bonded together using an adhesive (not shown).

[0043] 2(c), a laser beam is applied between the side surface of the protrusion 42 of the conductor 40 and the inner wall surface forming the opening 51 of the wiring board 50 to fuse the side surface of the protrusion 42 of the conductor 40 and the inner wall surface forming the opening 51 of the wiring board 50, thereby forming a weld 70. As shown by the solid arrow in FIG. 2(c), the laser beam is applied to the entire circumference of the protrusion 42 of the conductor 40 along the outer periphery of the protrusion 42. Therefore, the weld 70 is formed around the entire circumference of the protrusion 42 of the conductor 40.

[0044] Here, the laser light may be infrared, blue laser, or green laser. Because blue laser and green laser have high absorption rates in copper, using a blue laser or green laser when the conductor 40 is made of copper can improve productivity.

[0045] Furthermore, as shown in FIG. 2(c), the signal electrode 22 formed on the upper surface of the IGBT 20b is wire-bonded to the signal terminal 61 to form a wire 62.

[0046] Finally, as shown in FIG. 2(d), the inside of the container formed by the upper surface of the insulating substrate 10 and the case 60 is filled with sealing resin 63, and is heated and cured in an oven.

[0047] As described above, by providing conductor 40 between insulating substrate 10 and wiring board 50, and between semiconductor element 20 and wiring board 50, and laser welding conductor 40 and wiring board 50, welded portion 70 formed by laser welding can be prevented from reaching insulating substrate 10 and semiconductor element 20, thereby suppressing damage to insulating substrate 10 and semiconductor element 20.

[0048] Furthermore, by positioning the convex portion 42 of the conductor 40 so that it is inserted into the opening 51 of the wiring board 50 and welding the side surface of the convex portion 42 of the conductor 40 to the inner wall surface 52 that forms the opening 51 of the wiring board 50, the reliability of the joint between the wiring board 50 and the conductor 40 can be ensured regardless of the molding accuracy of the wiring board 50. For example, depending on the assembly state of the case 60, the wiring board 50 may be tilted vertically and not parallel to the conductor 40 to be welded, resulting in a gap between the upper surface of the conductor 40 and the wiring board 50. If there is a gap between the objects to be laser welded, voids or defects may occur during laser welding, making it difficult to achieve a strong joint. However, by welding the side surface of the convex portion 42 of the conductor 40 to the inner wall surface 52 that forms the opening 51 of the wiring board 50, the wiring board 50 and the conductor 40 can be firmly joined even if the wiring board 50 is tilted vertically.

[0049] Although Figures 1 and 2 show an example in which the conductor 40 is bonded to both the circuit layer 12 of the insulating substrate 10 and the electrode layer 21 of the semiconductor element 20 via the second conductive bonding material, it is sufficient that the conductor 40 is bonded to at least one of the circuit layer 12 of the insulating substrate 10 and the electrode layer 21 of the semiconductor element 20.

[0050] <Effects of the First Embodiment> The operation and effects of the semiconductor device 101 according to the first embodiment of the present disclosure will be described.

[0051] Because the semiconductor device 101 has a multilayer structure composed of multiple different materials, stress is generated due to differences in the thermal expansion coefficients of the materials as the temperature changes during operation of the semiconductor device 101. When the semiconductor device 101 operates, stress due to the differences in the thermal expansion coefficients is applied to the second conductive bonding material 32, which bonds at least one of the insulating substrate 10 and the semiconductor element 20 to the conductor 40 to which the wiring board 50 is welded. If stress concentrates in the second conductive bonding material 32, cracks will occur and propagate, making it impossible to ensure the reliability of the bond between at least one of the insulating substrate 10 and the semiconductor element 20 and the wiring board 50. In particular, if the second conductive bonding material 32 does not have a fillet shape 32f and only spreads between the upper surface of at least one of the insulating substrate 10 and the semiconductor element 20 and the lower surface of the conductor 40, forming a surface bond, stress is difficult to disperse, making it easier for cracks to occur and propagate in the second conductive bonding material 32.

[0052] A semiconductor device 101 according to a first embodiment of the present disclosure comprises an insulating substrate 10 having a circuit layer 12 formed on its upper surface, a semiconductor element 20 bonded to the circuit layer 12 of the insulating substrate 10 via a first conductive adhesive 31 and having an electrode layer 21 formed on its upper surface, a conductor 40 bonded to at least one of the circuit layer 12 of the insulating substrate 10 and the electrode layer 21 of the semiconductor element 20 via a second conductive adhesive 32, and a wiring board 50 welded onto the conductor 40, wherein the second conductive adhesive 32 has a fillet shape 32f that covers a portion of the side surface of the conductor 40.

[0053] The second conductive bonding material 32 included in the semiconductor device 101 according to the embodiment of the present disclosure has a fillet shape 32f that covers a portion of the side surface of the conductor 40. The fillet shape 32f of the second conductive bonding material 32 is a gentle shape with few corners where stress concentrates, so that stress applied to the second conductive bonding material 32 is uniformly distributed. Furthermore, the area of ​​the second conductive bonding material 32 is larger by the area of ​​the fillet shape 32f that covers a portion of the side surface of the conductor 40 compared to when the second conductive bonding material 32 does not have the fillet shape 32f, and stress is distributed over a wider range. Therefore, according to the semiconductor device 101 relating to embodiment 1 of the present disclosure, the second conductive bonding material 32 that bonds at least one of the insulating substrate 10 and the semiconductor element 20 to the conductor 40 to which the wiring board 50 is welded forms a fillet shape 32f that covers a portion of the side surface of the conductor 40, thereby reducing stress concentration on the second conductive bonding material 32 and ensuring the bonding reliability between the insulating substrate 10 or the semiconductor element 20 and the wiring board 50 connected via the second conductive bonding material 32 and the conductor 40.

[0054] Furthermore, in a semiconductor device including conductor 40 that does not have protrusion 42, i.e., a semiconductor device in which upper surface 41 of conductor 40 and the lower surface of wiring board 50 are laser welded, the reliability of the joint between wiring board 50 and conductor 40 may be reduced depending on the molding precision of wiring board 50. For example, if the molding precision of wiring board 50 is low, there is variation in the height of the portion of wiring board 50 that is to be welded to conductor 40, and there is a gap between conductor 40 and wiring board 50, voids and defects will occur during laser welding, making it difficult to achieve a strong joint.

[0055] The semiconductor device 101 according to the first embodiment of the present disclosure comprises a conductor 40 having a protrusion 42 protruding from an upper surface 41, and a wiring board 50 having an opening 51 into which the protrusion 42 of the conductor 40 is inserted, and the side of the protrusion 42 of the conductor 40 is welded to an inner wall surface 52 that forms the opening 51 of the wiring board 50.

[0056] According to semiconductor device 101 relating to embodiment 1 of the present disclosure, convex portion 42 of conductor 40 is inserted into opening 51 of wiring board 50, and the side of convex portion 42 of conductor 40 is welded to inner wall surface 52 forming opening 51 of wiring board 50, thereby ensuring the reliability of the joint between wiring board 50 and conductor 40 regardless of the molding accuracy of wiring board 50.

[0057] Furthermore, according to semiconductor device 101 according to the first embodiment of the present disclosure, when laser welding is performed, the irradiated laser is diffusely reflected in the gap between the side surface of protrusion 42 of conductor 40 and inner wall surface 52 that forms opening 51 of wiring board 50. The diffused reflection of the laser increases the laser absorption rate on the side surface of protrusion 42 of conductor 40 and inner wall surface 52 that forms opening 51 of wiring board 50. Therefore, according to semiconductor device 101 according to the first embodiment of the present disclosure, it is possible to suppress the laser output and shorten the laser irradiation time when welding conductor 40 and wiring board 50.

[0058] Furthermore, conductor 40 included in semiconductor device 101 according to the first embodiment of the present disclosure is formed so that the end of upper surface 41 is positioned outside opening 51 of wiring board 50 .

[0059] According to semiconductor device 101 of the first embodiment of the present disclosure, even if the laser irradiation position is misaligned when laser welding convex portion 42 of conductor 40 and wiring board 50, conductor 40, which is formed so that the end of upper surface 41 is positioned outside opening 51 of wiring board 50, blocks the optical path of the laser and prevents the laser from being directly irradiated on insulating substrate 10 or semiconductor element 20 connected to wiring board 50 via conductor 40. Therefore, according to semiconductor device 101 of the first embodiment of the present disclosure, when laser welding conductor 40 and wiring board 50, damage caused by laser irradiation to insulating substrate 10 or semiconductor element 20 connected to wiring board 50 via conductor 40 can be suppressed.

[0060] In this embodiment, an example has been shown in which the semiconductor element 20 is a diode 20a and an IGBT 20b with a silicon base material, but the semiconductor element 20 may also be an element with a wide band gap semiconductor such as silicon carbide or gallium nitride as a base material.

[0061] The semiconductor device 101 according to the first embodiment may be provided with a heat dissipation fin (not shown) to enhance heat dissipation. The heat dissipation fin is adhered to the lower part of the case 60 and joined via solder or the like to the lower surface conductor layer formed on the insulating substrate 10. The heat dissipation fin is made of, for example, copper or nickel-plated aluminum.

[0062] Variation 1. Next, a first modification of the first embodiment will be described. In the first embodiment, a semiconductor device 101 including a wiring board 50 having one end used as a wiring member to be welded to conductor 40 and the other end used as a connection terminal for connecting to the outside has been described. In the first modification, a semiconductor device 101a including a wiring board 50a including an internal wiring board 53 used as a wiring member to be welded to conductor 40 and an external wiring board 54 used as a connection terminal for connecting to the outside will be described.

[0063] A semiconductor device 101a according to a first modification of the first embodiment will be described with reference to Fig. 3. Fig. 3 is a schematic cross-sectional view showing the structure of the semiconductor device 101a. Fig. 3 shows a cross section corresponding to line AA in Fig. 1.

[0064] 3, wiring board 50a included in semiconductor device 101a is composed of internal wiring board 53 used as a wiring member to be welded to conductor 40, and external wiring board 54 used as a connection terminal for connecting to the outside. Internal wiring board 53 is a component corresponding to one end of wiring board 50 according to embodiment 1, and is provided inside case 60, with a portion of it arranged parallel to insulating substrate 10 and semiconductor element 20. External wiring board 54 is a component corresponding to the other end of wiring board 50 according to embodiment 1, and is partially integrated with case 60, with one end inside case 60 and the other end exposed to the outside from a side surface of case 60. One end of external wiring board 54 and internal wiring board 53 are laser-welded and electrically connected.

[0065] In semiconductor device 101 according to the first embodiment and semiconductor device 101a according to the first modification, temperature changes during operation can cause differences in the dimensional changes of the components due to differences in the coefficients of thermal expansion of the components, resulting in warping. In particular, wiring boards 50 and 50a, which are made of metal, and insulating substrate 10, which is made of ceramic, have a large difference in the coefficients of thermal expansion, and warping can occur due to the difference in the dimensional changes between wiring boards 50 and 50a and insulating substrate 10. The dimensional changes of wiring boards 50 and 50a due to temperature changes are greater than those of insulating substrate 10. The shorter the length of a component, the smaller the difference in dimensional changes between wiring boards 50 and 50a and insulating substrate 10, thereby reducing warping. Semiconductor device 101a according to Variation 1 of Embodiment 1 includes wiring board 50a, which is obtained by dividing wiring board 50 according to Embodiment 1 into two components and forming them as separate members. Wiring board 50a according to Variation 1 of Embodiment 1 is shorter than wiring board 50 according to Embodiment 1, and therefore undergoes less dimensional change due to thermal expansion. Therefore, semiconductor device 101a according to Variation 1 of Embodiment 1 can suppress the difference in dimensional change between wiring board 50a and insulating substrate 10 due to thermal expansion, thereby reducing warping of semiconductor device 101.

[0066] Variation 2. Modification 2 of Embodiment 1 will be described. In Embodiment 1, the semiconductor device 101 is a case-type module in which the case 60 is filled with the sealing resin 63. In Modification 2, the semiconductor device 101b is a transfer-molded module in which the sealing resin 63 is molded using a die.

[0067] A semiconductor device 101b according to a second modification of the first embodiment will be described with reference to Fig. 4. Fig. 4 is a schematic cross-sectional view showing the structure of the semiconductor device 101b. Fig. 4 shows a cross section corresponding to line AA in Fig. 1.

[0068] 4, semiconductor device 101b does not include case 60, and is a transfer mold type module in which each component is sealed with sealing resin 63. Semiconductor device 101b includes wiring board 50b having a lead frame structure different from that of embodiment 1, and a signal terminal (not shown). Wiring board 50b and signal terminal differ from wiring board 50 and signal terminal 61 of embodiment 1 in that they are not integrated with case 60. In addition, lower surface conductor layer 13 of insulating substrate 10 is exposed from sealing resin 63.

[0069] In the semiconductor device 101b according to the second modification of the first embodiment, the insulating substrate 10, the semiconductor element 20, the wiring board 50b, and the signal terminals are arranged in a mold, and the sealing resin 63 is injected into the mold and hardened to seal each component.

[0070] The semiconductor device 101b according to the second modification can be made smaller than the semiconductor device 101 according to the first embodiment, which is a case-type module. Furthermore, the semiconductor device 101b according to the second modification does not require the case 60, and therefore can be produced at low cost.

[0071] Embodiment 2 In the first embodiment of the present disclosure, a semiconductor device 101 has been described that includes a conductor 40 having a protrusion 42 protruding from the upper surface of the conductor 40. In the second embodiment, a semiconductor device 102 that includes a conductor 240 with a three-layer structure will be described. In the second embodiment, the same components as those in the first embodiment of the present disclosure are designated by the same reference numerals, and descriptions of the same or corresponding parts will be omitted. Hereinafter, a semiconductor device 102 according to the second embodiment will be described with reference to the drawings.

[0072] <Configuration of Second Embodiment> The configuration of a semiconductor device 102 according to a second embodiment of the present disclosure will be described with reference to Fig. 5. Fig. 3 is a schematic diagram showing the structure of the semiconductor device 102, with Fig. 5(a) being a schematic top view and Fig. 5(b) being a schematic cross-sectional view taken along line BB in Fig. 5(a). Note that, for ease of viewing, sealing resin 63 is omitted in Fig. 5(a), and wiring board 250 is indicated by a dotted line.

[0073] 5, semiconductor device 102 includes conductor 240 and wiring board 250, which are different from conductor 40 and wiring board 50 according to embodiment 1. The configuration of semiconductor device 102 other than conductor 240 and wiring board 250 is the same as that of semiconductor device 101 according to embodiment 1.

[0074] 5(b), the conductor 240 is a block-shaped metal composed of a first layer 243, a second layer 244, and a third layer 245. The conductor 240 has, for example, a length of 6 mm in the X direction, a length of 5 mm in the Y direction, and a thickness of 1 mm.

[0075] The conductor 240 is a clad material composed of a first layer 243, a second layer 244, and a third layer 245. Therefore, the first layer 243 is tightly adhered to the second layer 244, and the second layer 244 is tightly adhered to the third layer 245, with no gaps between them. Cold forging and rolling are common methods for producing clad materials, but the interfaces may also be connected by brazing, welding, or pressure welding.

[0076] The first layer 243 is a layer on the lower surface side of the conductor 240, and is bonded onto the circuit layer 12 of the insulating substrate 10 or the electrode layer 21 of the semiconductor element 20 via the second conductive bonding material 32. The material of the first layer 243 is a metal that has higher wettability with the second conductive bonding material 32 than the second layer 244, which is mainly composed of aluminum. The material of the first layer 243 is, for example, copper or nickel. The thickness of the first layer 243 is, for example, 0.1 mm.

[0077] The second layer 244 is a layer disposed on the first layer 243 and contains aluminum. The material of the second layer 244 may be, for example, aluminum or an aluminum alloy. The thickness of the second layer 244 is, for example, 0.8 mm.

[0078] Third layer 245 is a layer disposed on second layer 244, and is welded to wiring board 250. The material of third layer 245 may be any metal that can be laser welded to wiring board 250. The material of third layer 245 is, for example, copper or nickel, which are the same metals as wiring board 250. The thickness of third layer 245 is, for example, 0.1 mm.

[0079] A wiring board 250 is welded to the conductor 240. Specifically, the wiring board 250 is disposed on the third layer 245 of the conductor 240, and the lower surface of the wiring board 250 and the upper surface of the third layer 245 of the conductor 240 are welded to each other.

[0080] Like wiring board 50 according to the first embodiment, wiring board 250 is partially integrated with case 60, with one end provided inside case 60 and the other end provided outside case 60. One end of wiring board 250 is provided inside case 60, with a portion of it arranged parallel to insulating substrate 10 and semiconductor element 20, and is used as a wiring member to be welded to conductor 240. The other end of wiring board 250 is exposed from the side surface of case 60 and is used as a connection terminal for connection to the outside. Copper, for example, is used as the material for wiring board 250. Furthermore, wiring board 250 has a width of 6 mm and a thickness of 0.5 mm, for example.

[0081] As described above, semiconductor device 102 according to the second embodiment of the present disclosure includes conductor 240 provided between insulating substrate 10 or semiconductor element 20 and wiring board 50, and having second layer 244 containing aluminum. Aluminum is a metal that has a lower melting point than copper or nickel and is easily thermally deformed. Therefore, second layer 244 containing aluminum thermally deforms under high temperature conditions during operation of semiconductor device 102 and during manufacture of semiconductor device 102, thereby enabling stress caused by temperature changes to be alleviated.

[0082] In the present embodiment, the thickness of the conductor 240 is 0.1 mm for the first layer 243 and the third layer 245, and 0.8 mm for the second layer 244, but this is not limiting. In order to obtain the relaxation of stress caused by temperature changes by the second layer 244, it is desirable that the thickness of the second layer 244 be thicker than the thicknesses of the first layer 243 and the third layer 245.

[0083] <Manufacturing Method of Second Embodiment> Next, a method for manufacturing the semiconductor device 102 according to the second embodiment of the present disclosure will be described with reference to Fig. 6. Fig. 6 is a schematic diagram for explaining the method for manufacturing the semiconductor device 102. In Fig. 6(c), the laser light is indicated by a dotted arrow.

[0084] As shown in FIG. 6( a), first, the insulating substrate 10, the semiconductor element 20, and the conductor 240 are positioned and mounted. At this time, a first conductive bonding material 31 is placed between the insulating substrate 10 and the semiconductor element 20, and a second conductive bonding material 32 is placed between the insulating substrate 10, the semiconductor element 20, and the conductor 40. Next, the positioned and mounted insulating substrate 10, the semiconductor element 20, and the conductor 240 are placed in an atmosphere at or above the melting points of the first conductive bonding material 31 and the second conductive bonding material 32, to melt the first conductive bonding material 31 and the second conductive bonding material 32. After the first conductive bonding material 31 and the second conductive bonding material 32 have melted, they are cooled, and the insulating substrate 10, the semiconductor element 20, and the conductor 240 are bonded together.

[0085] It is desirable that the second conductor 240b bonded onto the electrode layer 21 of the semiconductor element 20 is positioned and bonded at the center of the electrode layer 21. It is also desirable that the amount of second conductive bonding material 32 that bonds the second conductor 240b onto the electrode layer 21 of the semiconductor element 20 is sufficient to cover the entire surface of the electrode layer 21. By bonding the second conductor 240b onto the electrode layer 21 of the semiconductor element 20 via the second conductive bonding material 32 in an amount that covers the entire surface of the electrode layer 21, a fillet can be formed around the entire periphery of the second conductor 240b.

[0086] Next, as shown in Fig. 6(b), the case 60 is attached to the joined insulating substrate 10, semiconductor element 20, and conductor 240. Here, the wiring board 250 and a portion of the signal terminal 61 are assembled to the case 60 so that they are integrated together. When attaching the case 60, the attachment position of the case 60 is determined so that the upper surface of the insulating substrate 10 and the case 60 form a container body. Then, the insulating substrate 10 and the case 60 are bonded together using an adhesive (not shown).

[0087] 6(c), a holder 80 such as a ball plunger is used to press down on wiring board 250 from above so that the underside of wiring board 250 and the upper surface of conductor 240 are in contact with each other without any gaps, and laser light is irradiated from above wiring board 250 to melt the underside of wiring board 250 and the upper surface of conductor 240, forming weld 270. The welding between the underside of wiring board 250 and the upper surface of conductor 240 is performed, for example, by irradiating a single point with laser light, thereby forming triangular pyramidal weld 270 as shown in FIG. 6(c). The laser light is not limited to being irradiated at a single point, and may be irradiated continuously at any point where wiring board 250 and conductor 240 are in contact with each other.

[0088] The laser light may be infrared, blue, or green. Because blue and green lasers are highly absorbed by copper, using a blue or green laser when the conductor 40 is made of copper can improve productivity.

[0089] Furthermore, as shown in FIG. 6(c), the signal electrode 22 formed on the upper surface of the IGBT 20b is wire-bonded to the signal terminal 61 to form a wire 62.

[0090] Finally, as shown in FIG. 6(d), the inside of the container formed by the upper surface of the insulating substrate 10 and the case 60 is filled with sealing resin 63, and is heated and cured in an oven.

[0091] As described above, by providing conductor 240 between insulating substrate 10 and wiring board 50, and between semiconductor element 20 and wiring board 250, and laser welding conductor 240 and wiring board 250, welded portion 270 formed by laser welding can be prevented from reaching insulating substrate 10 and semiconductor element 20, and damage to insulating substrate 10 and semiconductor element 20 can be suppressed.

[0092] Furthermore, the weld 270 formed by laser welding is mostly formed between the third layer 245 of the conductor 240 and the wiring board 250. The material of the third layer 245 is a metal that can be laser welded to the wiring board 250 made of copper, such as copper or nickel. A strong weld 270 can be obtained by laser welding the third layer 245 of the conductor 240 to the wiring board 250. If the conductor 240 does not have the third layer 245 and the second layer 244 containing aluminum is laser welded to the wiring board 250 made of copper, a brittle intermetallic compound layer is formed, forming the weld 70 in which cracks are likely to occur and propagate. The conductor 240 has a configuration including the second layer 244 and the third layer 245, which is disposed on the second layer 244 and is made of a metal that can be laser welded to the wiring board 250 made of copper, and therefore the conductor 240 and the wiring board 250 are firmly welded by laser welding.

[0093] Furthermore, the material of the first layer 243 of the conductor 240, which is bonded to the insulating substrate 10 and the semiconductor element 20 via the second conductive bonding material 32, is a metal that has higher wettability with the second conductive bonding material 32 than the second layer 244 containing aluminum, such as copper or nickel. If the conductor 240 does not have the first layer 243 and the second layer 244 containing aluminum is bonded to the insulating substrate 10 and the semiconductor element 20 via the second conductive bonding material 32, it is necessary to treat the strong oxide film specific to aluminum that forms on the surface of the second layer 244, which reduces the wettability of the second conductive bonding material 32, and this increases the cost of bonding. The conductor 240 has a configuration that has higher wettability with the second conductive bonding material 32 than the second layer 244 and is bonded to the insulating substrate 10 or the semiconductor element 20 via the second conductive bonding material 32. Therefore, the insulating substrate 10, the semiconductor element 20, and the conductor 240 can be firmly welded to each other by laser welding at low cost.

[0094] 5 and 6 show an example in which the conductor 240 is bonded to both the circuit layer 12 of the insulating substrate 10 and the electrode layer 21 of the semiconductor element 20 via the second conductive bonding material, but it is sufficient that the conductor 240 is bonded to at least one of the circuit layer 12 of the insulating substrate 10 and the electrode layer 21 of the semiconductor element 20.

[0095] <Effects of the Second Embodiment> The operation and effects of the semiconductor device 102 according to the second embodiment of the present disclosure will be described.

[0096] A semiconductor device 102 according to a second embodiment of the present disclosure includes an insulating substrate 10 having a circuit layer 12 formed on its upper surface, a semiconductor element 20 bonded to the circuit layer 12 of the insulating substrate 10 via a first conductive bonding material 31 and having an electrode layer 21 formed on its upper surface, a conductor 240 bonded to at least one of the circuit layer 12 of the insulating substrate 10 and the electrode layer 21 of the semiconductor element 20 via a second conductive bonding material 32, and a wiring board 250 welded onto the conductor 40, where the second conductive bonding material 32 has a fillet shape that covers a portion of a side surface of the conductor 240. The conductor 240 includes a first layer 243 bonded to at least one of the circuit layer 12 of the insulating substrate 10 and the electrode layer 21 of the semiconductor element 20 via the second conductive bonding material 32, a second layer 244 containing aluminum and disposed on the first layer 243, and a third layer 245 disposed on the second layer 244 and welded to the wiring board 250.

[0097] The semiconductor device 102 according to the second embodiment of the present disclosure includes a conductor 240 having a second layer 244 containing aluminum, which is disposed between at least one of the insulating substrate 10 and the semiconductor element 20 and the wiring board 250. Aluminum has a lower melting point than copper or nickel and is easily thermally deformed. Therefore, the second layer 244 containing aluminum deforms when stress is applied due to a difference in the thermal expansion coefficient between materials caused by a temperature change, thereby relieving the stress. When the stress caused by the difference in the thermal expansion coefficient between materials caused by a temperature change is relieved by the conductor 240 having the second layer 244 containing aluminum, stress concentration on the second conductive bonding material 32 that bonds the insulating substrate 10 or the semiconductor element 20 to the conductor 240 to which the wiring board 250 is welded is reduced, thereby suppressing the occurrence and propagation of cracks in the second conductive bonding material 32. Therefore, according to the semiconductor device 102 relating to the second embodiment of the present disclosure, the conductor 240 having the second layer 244 containing aluminum relieves stress, thereby ensuring the bonding reliability between the insulating substrate 10 or the semiconductor element 20 and the wiring board 250 connected via the second conductive bonding material 32 and the conductor 240.

[0098] Furthermore, according to the semiconductor device 102 relating to the second embodiment of the present disclosure, the conductor 240 having the second layer 244 containing aluminum relieves stress, thereby relieving the stress applied to the circuit layer 12 of the insulating substrate 10 or the electrode layer 21 of the semiconductor element 20, and preventing damage to at least one of the circuit layer 12 of the insulating substrate 10 and the electrode layer 21 of the semiconductor element 20 to which the conductor 240 is bonded.

[0099] Furthermore, the first layer 243 constituting the conductor 240 is bonded to at least one of the insulating substrate 10 and the semiconductor element 20 via the second conductive bonding material 32. The material of the first layer 243 of the conductor 240 is a metal that has higher wettability with the second conductive bonding material 32 than the second layer 244 containing aluminum, i.e., copper or nickel. Therefore, the bond between the first layer 243 of the conductor 240 and at least one of the insulating substrate 10 and the semiconductor element 20 is stronger than the bond between the second layer 244 of the conductor 240 and at least one of the insulating substrate 10 and the semiconductor element 20. Therefore, according to the semiconductor device 102 of the second embodiment of the present disclosure, the semiconductor device 102 includes a conductor 240 having a first layer 243 that has higher wettability with the second conductive bonding material 32 than the second layer 244 containing aluminum and that bonds to at least one of the insulating substrate 10 and the semiconductor element 20 via the second conductive bonding material 32, so that high bonding reliability can be obtained between the conductor 240 and at least one of the insulating substrate 10 and the semiconductor element 20.

[0100] Third layer 245 constituting conductor 240 is laser welded to wiring board 250. The material of third layer 245 of conductor 240 is a metal that can be laser welded to wiring board 250 made of copper, i.e., copper or nickel. Here, when wiring board 250 made of copper and second layer 244 containing aluminum are laser welded, a brittle intermetallic compound layer is formed at weld 70, making cracks more likely to occur and progress. When wiring board 250 made of copper and third layer 245 made of copper or nickel are laser welded, a brittle intermetallic compound layer is not formed, and a strong weld 70 can be obtained. Therefore, according to the semiconductor device 102 relating to the second embodiment of the present disclosure, the semiconductor device 102 is provided with a conductor 240 made of copper or nickel and having a third layer 245 that is welded to the wiring board 250, and therefore, high bonding reliability can be obtained between the conductor 240 and the wiring board 250.

[0101] Embodiment 3 In the second embodiment of the present disclosure, a semiconductor device 102 has been described that includes a conductor 240 having a three-layer structure composed of a first layer 243, a second layer 244, and a third layer 245. In the third embodiment, a semiconductor device 103 has been described that includes a conductor 340 having a two-layer structure composed of a second layer 344 and a third layer 345. In the third embodiment, the same components as those in the second embodiment of the present disclosure are designated by the same reference numerals, and descriptions of the same or corresponding parts will be omitted. Hereinafter, a semiconductor device 103 according to the third embodiment will be described with reference to the drawings.

[0102] <Configuration of Third Embodiment> A semiconductor device 103 according to a third embodiment will be described with reference to Fig. 7. Fig. 7 is a schematic diagram showing the structure of the semiconductor device 103, with Fig. 7(a) being a schematic top view and Fig. 7(b) being a schematic cross-sectional view taken along line CC in Fig. 7. Note that, for ease of viewing, sealing resin 63 is omitted in Fig. 7(a), and wiring board 250 is indicated by a dotted line.

[0103] 7, the semiconductor device 103 includes an insulating substrate 310, a semiconductor element 320, a second conductive bonding material 332, and a conductor 340, which are different from the configuration of the second embodiment. The configuration of the semiconductor device 103 is the same as that of the semiconductor device 102 according to the second embodiment, except for the insulating substrate 310, the semiconductor element 320, the second conductive bonding material 332, and the conductor 340.

[0104] Insulating substrate 310 differs from insulating substrate 10 included in semiconductor device 102 according to embodiment 2 in that circuit layer 312 formed on the upper surface is a layer containing aluminum. The material of circuit layer 312 may be, for example, aluminum or an aluminum alloy.

[0105] A semiconductor element 320 is bonded to the top of a circuit layer 312 formed on an insulating substrate 310 via a first conductive bonding material 31, and a first conductor 340a is bonded to the top of the circuit layer 312 via a second conductive bonding material 332. A metal film is formed on a portion of the surface of the circuit layer 312 of the insulating substrate 310 to which the semiconductor element 320 is bonded, in order to improve bonding with the first conductive bonding material 31. The metal film formed on the surface of the circuit layer 312 is made of, for example, nickel, gold, titanium, or the like.

[0106] The semiconductor element 320 differs from the semiconductor element 20 included in the semiconductor device 102 according to the second embodiment in that the electrode layer 321 formed on the upper surface is a layer containing aluminum. The material of the electrode layer 321 may be, for example, aluminum or an aluminum alloy. Furthermore, no metal film is formed on the surface of the electrode layer 321 included in the semiconductor device 103.

[0107] The conductor 340 differs from the conductor 240 according to the second embodiment, which is a block-shaped metal having a three-layer structure, in that the conductor 340 is a two-layer block-shaped metal consisting of a second layer 344 and a third layer 345. The conductor 340 has, for example, a length of 6 mm in the X direction, a length of 5 mm in the Y direction, and a thickness of 1 mm.

[0108] The second layer 344 of the conductor 340 is a layer containing aluminum, similar to the second layer 244 of the conductor 240 according to embodiment 2. However, unlike the second layer 244 of the conductor 240 according to embodiment 2, the second layer 344 of the conductor 340 is bonded onto the circuit layer 312 of the insulating substrate 310 or the electrode layer 321 of the semiconductor element 320 via a second conductive bonding material 332. The material of the second layer 344 may be, for example, aluminum or an aluminum alloy, and the thickness of the second layer 244 is, for example, 0.5 mm.

[0109] Similar to third layer 245 of conductor 240 according to the second embodiment, third layer 345 of conductor 340 is a layer disposed on second layer 344 and is welded to wiring board 250. The material of third layer 345 may be any metal that can be laser welded to wiring board 250. The material of third layer 345 is, for example, copper or nickel, which are the same metals as wiring board 250. The thickness of third layer 345 is, for example, 0.5 mm.

[0110] The second conductive bonding material 332, which bonds the circuit layer 312 of the insulating substrate 310 or the electrode layer 321 of the semiconductor element 320 to the second layer 344 of the conductor 340, is a silver sintered material primarily composed of silver oxide. Silver sintered materials primarily composed of silver oxide are excellent bonding materials for bonding aluminum to aluminum. Because the circuit layer 312 of the insulating substrate 310, the electrode layer 321 of the semiconductor element 320, and the second layer 344 of the conductor 340 are layers containing aluminum, they can be bonded using a silver sintered material primarily composed of silver oxide. The second conductive bonding material 332 also has a fillet shape that covers a portion of the side surface of the conductor 340.

[0111] As described above, similar to semiconductor device 102 according to embodiment 2 of the present disclosure, semiconductor device 103 according to embodiment 3 of the present disclosure includes conductor 340 having second layer 344 containing aluminum, which is provided between insulating substrate 310 or semiconductor element 320 and conductor 340. Second layer 244 containing aluminum, which is a metal that has a lower melting point and is more susceptible to thermal deformation than copper or nickel, thermally deforms under high temperature conditions during operation of semiconductor device 103 and during manufacture of semiconductor device 103, and can relieve stress caused by temperature changes.

[0112] Furthermore, the semiconductor device 103 according to the third embodiment of the present disclosure includes a second conductive bonding material 332, which is a silver sintered material mainly composed of silver oxide, that bonds the circuit layer 312 of the insulating substrate 310, which is a layer containing aluminum, and the electrode layer 321 of the semiconductor element 320, to the second layer 344 of the conductor 340, which is a layer containing aluminum.

[0113] Aluminum forms a strong oxide film on its surface, which reduces its wettability with solder materials. Therefore, when joining aluminum to dissimilar metals via solder, a metal film must be formed to improve the bond with the solder. To form a metal film on aluminum, the oxide film must first be removed using a highly corrosive etching solution. However, the wastewater generated during oxide film removal places a significant burden on the environment. Furthermore, the process of removing the oxide film from the aluminum surface and then forming a metal film is costly. Furthermore, when forming a metal film on the surfaces of the circuit layer 312 of the insulating substrate 310 and the electrode layer 321 of the semiconductor element 320 to improve the bond with the solder, the metal film must be thick to prevent pinholes. However, variations in the thickness of the metal film can change the resistance and capacitance of the circuit layer 312 and the electrode layer 321, potentially degrading signal transmission characteristics.

[0114] In semiconductor device 103 according to the third embodiment of the present disclosure, aluminum-containing layers are bonded together using a silver sintered material primarily composed of silver oxide, which is an excellent bonding material for bonding aluminum layers together. This eliminates the need to form metal films on circuit layer 312 of insulating substrate 310 and electrode layer 321 of semiconductor element 320 for bonding with conductor 340. Therefore, there is no need to remove oxide films formed on the aluminum surfaces to bond insulating substrate 310 or semiconductor element 320 to conductor 340, and no waste liquid is generated due to oxide film removal. This allows bonding insulating substrate 310 or semiconductor element 320 to conductor 340 while reducing environmental impact. Furthermore, this eliminates the need to remove oxide films formed on the surfaces of circuit layer 312 of insulating substrate 310, electrode layer 321 of semiconductor element 320, and second layer 344 of conductor 340 and form metal films, allowing bonding insulating substrate 310 or semiconductor element 320 to conductor 340 at low cost. Furthermore, in order to join the insulating substrate 310 or the semiconductor element 320 to the conductor 340, no metal film is formed on the surfaces of the circuit layer 312 of the insulating substrate 310 and the electrode layer 321 of the semiconductor element 320, so that the insulating substrate 310 or the semiconductor element 320 can be joined to the conductor 340 without degrading the signal transmission characteristics.

[0115] In the present embodiment, the thickness of the conductor 340 is 0.5 mm for the second layer 344 and the third layer 345, but this is not limiting. In order to alleviate stress caused by temperature changes by the second layer 344, it is desirable that the thickness of the second layer 344 be equal to or greater than the thickness of the third layer 245.

[0116] <Manufacturing Method of Third Embodiment> The method for manufacturing the semiconductor device 103 according to the third embodiment of the present disclosure is similar to the method for manufacturing the semiconductor device 102 according to the second embodiment of the present disclosure, and therefore a detailed description thereof will be omitted.

[0117] In the method of manufacturing semiconductor device 103 according to the third embodiment, similarly to the second embodiment of the present disclosure, conductors 340 are provided between insulating substrate 310 and wiring board 250 and between semiconductor element 320 and wiring board 250, and conductors 340 are laser-welded to wiring board 250. By providing conductors 340 between semiconductor element 320 and wiring board 250, welded portions 270 formed by laser welding are prevented from reaching insulating substrate 310 and semiconductor element 320, and damage to insulating substrate 310 and semiconductor element 320 can be suppressed.

[0118] Furthermore, in the manufacturing method of semiconductor device 103 according to the third embodiment, similarly to the second embodiment of the present disclosure, welded portion 270 formed by laser welding is mostly formed between third layer 345 of conductor 340 and wiring board 250. The material of third layer 345 is a metal that can be laser welded to wiring board 250, which is made of copper, and therefore, by laser welding third layer 345 of conductor 340 and wiring board 250 together, conductor 340 and wiring board 250 can be firmly welded together.

[0119] Although Figure 7 shows an example in which the conductor 340 is bonded to both the circuit layer 312 of the insulating substrate 310 and the electrode layer 321 of the semiconductor element 320 via the second conductive bonding material 332, it is sufficient that the conductor 340 is bonded to at least one of the circuit layer 312 of the insulating substrate 310 and the electrode layer 321 of the semiconductor element 320.

[0120] <Effects of the Third Embodiment> The operation and effects of the semiconductor device 103 according to the third embodiment of the present disclosure will be described.

[0121] A semiconductor device 103 according to a third embodiment of the present disclosure includes an insulating substrate 310 having a circuit layer 312 formed on its upper surface, a semiconductor element 320 bonded to the circuit layer 312 of the insulating substrate 310 via a first conductive bonding material 31 and having an electrode layer 321 formed on its upper surface, a conductor 340 bonded to at least one of the circuit layer 312 of the insulating substrate 310 and the electrode layer 321 of the semiconductor element 320 via a second conductive bonding material 332, and a wiring board 250 welded onto the conductor 340. The second conductive bonding material 332 has a fillet shape that covers a portion of the side surface of the conductor 340. The circuit layer 312 and the electrode layer 321 are layers containing aluminum. The second conductive bonding material 32 is a sintered silver material primarily composed of silver oxide. The conductor 340 includes a second layer 344 that contains aluminum and is bonded to at least one of the circuit layer 12 of the insulating substrate 310 and the electrode layer 321 of the semiconductor element 320 via a second conductive bonding material 332, and a third layer 345 that is disposed on the second layer 344 and welded to the wiring board 250.

[0122] Similar to semiconductor device 102 according to the second embodiment of the present disclosure, semiconductor device 103 according to the third embodiment of the present disclosure includes conductor 340 having second layer 344 containing aluminum, which is disposed between wiring board 250 and at least one of insulating substrate 310 and semiconductor element 320. Aluminum has a lower melting point than copper or nickel and is easily deformed by heat. Therefore, second layer 344 containing aluminum deforms when stress is applied due to the difference in thermal expansion coefficient between materials caused by temperature changes, thereby relieving the stress. Therefore, according to semiconductor device 103 according to the third embodiment of the present disclosure, conductor 340 having second layer 344 containing aluminum relieves stress, thereby ensuring the reliability of the bond between insulating substrate 310 or semiconductor element 320 and wiring board 350 connected via conductor 340. Furthermore, according to the semiconductor device 103 relating to the third embodiment of the present disclosure, the conductor 340 having the second layer 344 containing aluminum relieves stress, thereby relieving the stress applied to the circuit layer 312 of the insulating substrate 310 or the electrode layer 321 of the semiconductor element 320 to which the conductor 340 is bonded, and thus preventing damage to the circuit layer 312 of the insulating substrate 310 or the electrode layer 321 of the semiconductor element 320 to which the conductor 340 is bonded.

[0123] Furthermore, semiconductor device 103 according to the third embodiment of the present disclosure includes second conductive bonding material 332, which is a silver sintered material mainly composed of silver oxide, that bonds circuit layer 312 of insulating substrate 310 and electrode layer 321 of semiconductor element 320, which are layers containing aluminum, to second layer 344 of conductor 340, which is also a layer containing aluminum. Because semiconductor device 103 according to the third embodiment of the present disclosure includes a silver sintered material mainly composed of silver oxide that bonds layers containing aluminum, circuit layer 312 of insulating substrate 310, electrode layer 321 of semiconductor element 320, and second layer 344 of conductor 340 included in semiconductor device 103 do not have a metal film that needs to be formed on the surface of an aluminum-containing layer when joining aluminum and a dissimilar metal via a solder material, and no treatment is performed to remove the oxide film on the aluminum surface to form a metal film. Therefore, according to semiconductor device 103 according to the third embodiment of the present disclosure, it is not necessary to remove the oxide film formed on the aluminum surface in order to bond insulating substrate 310 or semiconductor element 320 to conductor 340, and no waste liquid is generated due to oxide film removal, so it is possible to bond insulating substrate 310 or semiconductor element 320 to conductor 340 while reducing the burden on the environment. Furthermore, according to semiconductor device 103 according to the third embodiment of the present disclosure, it is possible to bond insulating substrate 310 or semiconductor element 320 to conductor 340 at low cost without performing processes to remove oxide films formed on the surfaces of circuit layer 312 of insulating substrate 310, electrode layer 321 of semiconductor element 320, and second layer 344 of conductor 340 and form metal films. Furthermore, according to the semiconductor device 103 relating to the third embodiment of the present disclosure, since no metal film is formed on the surfaces of the circuit layer 312 of the insulating substrate 310 and the electrode layer 321 of the semiconductor element 320 to join the insulating substrate 310 or the semiconductor element 320 to the conductor 340, the insulating substrate 310 or the semiconductor element 320 can be joined to the conductor 340 without degrading the signal transmission characteristics.

[0124] Third layer 345 of conductor 340 is laser-welded to wiring board 250, similar to third layer 245 of conductor 240 according to the second embodiment of the present disclosure. Third layer 345 of conductor 340 is made of a metal that can be laser-welded to wiring board 250 made of copper, i.e., copper or nickel. When wiring board 250 made of copper is laser-welded to second layer 344 containing aluminum, a brittle intermetallic compound layer is formed at weld 70, making cracks more likely to occur and propagate. When wiring board 250 made of copper is laser-welded to third layer 345 made of copper or nickel, a brittle intermetallic compound layer is not formed, and a strong weld 270 can be obtained. Therefore, according to the semiconductor device 103 relating to the third embodiment of the present disclosure, since the semiconductor device 103 is provided with a conductor 340 made of copper or nickel and having a third layer 345 that is welded to the wiring board 250, high bonding reliability can be obtained between the conductor 340 and the wiring board 250.

[0125] Embodiment 4 In this embodiment, the semiconductor devices according to the above-described first to third embodiments are applied to a power conversion device. Although the present disclosure is not limited to a specific power conversion device, a case in which the present disclosure is applied to a three-phase inverter will be described below as a fourth embodiment.

[0126] FIG. 8 is a block diagram showing the configuration of a power conversion system to which the power conversion device according to this embodiment is applied.

[0127] The power conversion system shown in Fig. 8 is composed of a power supply 400, a power conversion device 500, and a load 600. The power supply 400 is a DC power supply and supplies DC power to the power conversion device 500. The power supply 400 can be composed of various components, such as a DC system, a solar cell, or a storage battery, or it may be composed of a rectifier circuit or an AC / DC converter connected to an AC system. The power supply 400 may also be composed of a DC / DC converter that converts DC power output from a DC system into a predetermined power.

[0128] The power conversion device 500 is a three-phase inverter connected between the power source 400 and the load 600, and converts DC power supplied from the power source 400 into AC power and supplies the AC power to the load 600. As shown in Fig. 8, the power conversion device 500 includes a main conversion circuit 501 that converts DC power into AC power and outputs it, and a control circuit 503 that outputs a control signal to the main conversion circuit 501 to control the main conversion circuit 501.

[0129] The load 600 is a three-phase electric motor driven by AC power supplied from the power conversion device 500. The load 600 is not limited to a specific application, but is an electric motor mounted on various electrical devices, and is used as an electric motor for, for example, a hybrid vehicle, an electric vehicle, a railroad car, an elevator, or an air conditioning device.

[0130] The power conversion device 500 will be described in detail below. The main conversion circuit 501 includes switching elements and freewheel diodes (not shown). The switching elements convert DC power supplied from the power supply 400 into AC power, which is supplied to the load 600. The main conversion circuit 501 can have a variety of specific circuit configurations. The main conversion circuit 501 according to this embodiment is a two-level, three-phase full-bridge circuit, and can be configured with six switching elements and six freewheel diodes connected in antiparallel to each switching element. At least one of the switching elements and freewheel diodes of the main conversion circuit 501 is a switching element or freewheel diode included in a semiconductor device 502 corresponding to any one of the semiconductor devices according to the first to third embodiments. Two of the six switching elements are connected in series to form upper and lower arms, and each upper and lower arm constitutes one phase (U phase, V phase, and W phase) of the full-bridge circuit. The output terminals of each upper and lower arm, i.e., the three output terminals of the main conversion circuit 501, are connected to the load 600.

[0131] The main conversion circuit 501 also includes a drive circuit (not shown) that drives each switching element, but the drive circuit may be built into the semiconductor device 502, or may be provided separately from the semiconductor device 502. The drive circuit generates drive signals that drive the switching elements of the main conversion circuit 501 and supplies them to the control electrodes of the switching elements of the main conversion circuit 501. Specifically, in accordance with control signals from a control circuit 503 (described later), the drive circuit outputs to the control electrodes of each switching element a drive signal that turns the switching element on and a drive signal that turns the switching element off. When maintaining a switching element in the on state, the drive signal is a voltage signal (on signal) that is equal to or greater than the threshold voltage of the switching element, and when maintaining a switching element in the off state, the drive signal is a voltage signal (off signal) that is equal to or less than the threshold voltage of the switching element.

[0132] The control circuit 503 controls the switching elements of the main conversion circuit 501 so that the desired power is supplied to the load 600. Specifically, it calculates the time (on time) that each switching element of the main conversion circuit 501 should be in the on state based on the power to be supplied to the load 600. For example, the main conversion circuit 501 can be controlled by PWM control, which modulates the on time of the switching elements according to the voltage to be output. Then, it outputs a control command (control signal) to a drive circuit provided in the main conversion circuit 501 so that an on signal is output to a switching element that should be in the on state at each time point, and an off signal is output to a switching element that should be in the off state at each time point. In accordance with this control signal, the drive circuit outputs an on signal or an off signal as a drive signal to the control electrode of each switching element.

[0133] In the power conversion device according to this embodiment, the semiconductor devices according to embodiments 1 to 3 are applied as the semiconductor device 502 constituting the main conversion circuit 501, so that the joining reliability of the wiring boards 50, 250 can be ensured.

[0134] In the present embodiment, an example in which the present disclosure is applied to a two-level three-phase inverter has been described, but the present disclosure is not limited to this and can be applied to various power conversion devices. In the present embodiment, a two-level power conversion device is described, but a three-level or multi-level power conversion device may also be used. In addition, when power is supplied to a single-phase load, the present disclosure may also be applied to a single-phase inverter. Furthermore, when power is supplied to a DC load or the like, the present disclosure can also be applied to a DC / DC converter or an AC / DC converter.

[0135] Furthermore, the power conversion device to which the present disclosure is applied is not limited to cases in which the above-mentioned load is an electric motor, but can also be used, for example, as a power supply device for an electric discharge machine, a laser processing machine, an induction heating cooker, or a contactless power supply system, and can also be used as a power conditioner for a solar power generation system, a power storage system, etc.

[0136] Although the present disclosure has been described above based on the embodiments, the present disclosure is not limited to the embodiments. Furthermore, appropriate combinations, modifications, or omissions of the embodiments are also within the scope of the technical ideas shown in the embodiments.

[0137] Various aspects of the present disclosure are summarized below as appendices.

[0138] (Appendix 1) an insulating substrate having a circuit layer formed on its upper surface; a semiconductor element bonded onto the circuit layer of the insulating substrate via a first conductive bonding material, and having an electrode layer formed on an upper surface thereof; a conductor bonded to at least one of the circuit layer of the insulating substrate and the electrode layer of the semiconductor element via a second conductive bonding material; a wiring board welded to the conductor; Equipped with The second conductive bonding material has a fillet shape that covers a side surface of the conductor. Semiconductor device. (Appendix 2) the conductor has a protrusion protruding from an upper surface of the conductor, the wiring board has an opening into which the protrusion of the conductor is inserted, a side surface of the convex portion of the conductor and an inner wall surface that forms the opening of the wiring board are welded together; 2. The semiconductor device according to claim 1. (Appendix 3) the conductor is formed so that an end of the upper surface is positioned outside the opening of the wiring board; 3. The semiconductor device according to claim 2. (Appendix 4) The conductor is composed of a first layer bonded to at least one of the circuit layer of the insulating substrate and the electrode layer of the semiconductor element via the second conductive bonding material, a second layer disposed on the first layer and containing aluminum, and a third layer disposed on the second layer and welded to the wiring board. 4. The semiconductor device according to claim 1, wherein the semiconductor device is a semiconductor device having a first insulating film. (Appendix 5) the circuit layer and the electrode layer are layers containing aluminum, the second conductive bonding material is a silver sintered material containing silver oxide as a main component, The conductor includes aluminum and is composed of a second layer bonded to at least one of the circuit layer of the insulating substrate and the electrode layer of the semiconductor element via the second conductive bonding material, and a third layer disposed on the second layer and welded to the wiring board. 4. The semiconductor device according to claim 1, wherein the semiconductor device is a semiconductor device having a first insulating film. (Appendix 6) The first conductive bonding material and the second conductive bonding material are a solder material, a brazing material, or a silver sintered material. 5. The semiconductor device according to claim 1. (Appendix 7) The third layer is made of copper or nickel. 6. The semiconductor device according to claim 4 or 5. (Appendix 8) The first layer is made of copper or nickel. 5. The semiconductor device according to claim 4. (Appendix 9) a main conversion circuit having the semiconductor device according to any one of Supplementary Note 1 to Supplementary Note 8, which converts input power and outputs the converted power; a control circuit that outputs a control signal to the main conversion circuit to control the main conversion circuit; A power conversion device comprising: [Explanation of symbols]

[0139] 10, 310 insulating substrate 11 Insulating layer 12, 312 circuit layers 13 Bottom conductor layer 20, 320 semiconductor elements 20a, 320a diode 20b, 320b IGBT 21, 321 electrode layer 21a, 321a Diode electrode layer 21b, 321b IGBT electrode layer 22 signal electrode 31 First conductive adhesive material 32 Second conductive adhesive material 32f fillet shape 40, 240, 340 conductors 40a, 240a, 340a First conductor 40b, 240b, 340b Second conductor 41 Upper surface of conductor 42 Convex part 43 Bottom 243 1st layer 244, 344 2nd layer 245, 345 3rd layer 50, 50a, 50b, 250 wiring board 51 Opening 52 Inner wall surface 53 Internal wiring board 54 External wiring board 60 cases 61 Signal terminal 62 wires 63 Sealing resin 70, 270 welds 80 Holder 101, 101a, 101b, 102, 103 semiconductor device 400 power supply 500 Power Converter 501 Main conversion circuit 502 Semiconductor devices 503 Control circuit 600 load

Claims

1. an insulating substrate having a circuit layer formed on its upper surface; a semiconductor element bonded to the circuit layer of the insulating substrate via a first conductive bonding material and having an electrode layer formed on an upper surface thereof; a conductor bonded to at least one of the circuit layer of the insulating substrate and the electrode layer of the semiconductor element via a second conductive bonding material; a wiring board welded to the conductor; Equipped with the second conductive bonding material has a fillet shape that covers a side surface of the conductor; Semiconductor device.

2. the conductor has a protrusion protruding from an upper surface of the conductor, the wiring board has an opening into which the protrusion of the conductor is inserted, a side surface of the convex portion of the conductor and an inner wall surface that forms the opening of the wiring board are welded together; The semiconductor device according to claim 1 .

3. the conductor is formed so that an end of the upper surface is positioned outside the opening of the wiring board; The semiconductor device according to claim 2 .

4. The conductor is composed of a first layer bonded to at least one of the circuit layer of the insulating substrate and the electrode layer of the semiconductor element via the second conductive bonding material, a second layer disposed on the first layer and containing aluminum, and a third layer disposed on the second layer and welded to the wiring board. The semiconductor device according to claim 1 .

5. the circuit layer and the electrode layer are layers containing aluminum, the second conductive bonding material is a silver sintered material containing silver oxide as a main component, the conductor includes aluminum and is composed of a second layer bonded to at least one of the circuit layer of the insulating substrate and the electrode layer of the semiconductor element via the second conductive bonding material, and a third layer disposed on the second layer and welded to the wiring board. The semiconductor device according to claim 1 .

6. The first conductive bonding material and the second conductive bonding material are a solder material, a brazing material, or a silver sintered material. The semiconductor device according to claim 1 .

7. the third layer is made of copper or nickel; 6. The semiconductor device according to claim 4.

8. The first layer is made of copper or nickel. The semiconductor device according to claim 4 .

9. a main conversion circuit having the semiconductor device according to claim 1, which converts input power and outputs the converted power; a control circuit that outputs a control signal to the main conversion circuit to control the main conversion circuit; A power conversion device comprising:

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