Semiconductor device

Abstract

To provide a junction structure, in which suppression of surface damage due to a junction between two metallic members is performed, a junction method thereof, and a semiconductor device comprising the junction structure.SOLUTION: A semiconductor device B2 comprises: a plurality of switching elements; a sealing resin 60 that seals each of the plurality of switching elements; an input terminal 31 that includes a first pad part 311 and a terminal part 312; an input terminal 32 that includes a second pad part 321 and a terminal part 322; an output terminal that includes a third pad part and a third terminal part; and a supply terminal 71 that is conductively joined up with the terminal part 312. The input terminals 31 and 32, and the output terminal are electrically connected to the plurality of switching elements. The sealing resin surrounds at least a portion of the terminal parts 312 and 322 and at least a portion of the third terminal part seen in a z direction. Conductive junction between the supply terminal 71 and the terminal part 312 comprises: a supply terminal junction 93E of a weld zone 93 in which a portion of the supply terminal 71 and a portion of the terminal part 312 are welded.SELECTED DRAWING: Figure 24

Description

[Technical Field]

[0001] The present disclosure relates to a bonded structure in which a first metal member and a second metal member are bonded, a semiconductor device including the bonded structure, and a method for bonding a first metal member and a second metal member. [Background technology]

[0002] In recent years, semiconductor devices have become more and more efficient with increasing current, and therefore require lower internal resistance. In response to this demand, techniques have been developed for directly bonding two metal members without using bonding wires or the like. For example, Patent Document 1 discloses a technique for bonding two metal members (a metal terminal and a metal plate) by ultrasonic bonding. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-221527 Summary of the Invention [Problem to be solved by the invention]

[0004] In ultrasonic bonding, two metal members are joined by applying ultrasonic vibrations while pressing one metal member against the other. However, in ultrasonic bonding, the two metal members rub against each other, which can cause wear on each metal member. Such surface damage can cause performance degradation in semiconductor devices.

[0005] The present disclosure has been made in view of the above-mentioned problems, and its purpose is to provide a bonded structure that suppresses surface damage caused by bonding two metal members, a semiconductor device including the bonded structure, and a method for bonding two metal members. [Means for solving the problem]

[0006] A joined structure provided by a first aspect of the present disclosure is a joined structure in which a first metal member and a second metal member overlap when viewed in a first direction, and the first metal member and the second metal member are joined together, and in the area where the first metal member and the second metal member overlap, a weld is provided where a portion of the first metal member and a portion of the second metal member are fused together, and the weld has an annular outer edge when viewed in the first direction, and a plurality of linear marks when viewed in the first direction, each extending from inside the weld toward the outer edge, and each of the plurality of linear marks is curved so as to bulge toward one side of the annular direction along the outer edge.

[0007] In a preferred embodiment of the joined structure, the outer peripheral edge is annular about a first reference point, and each of the plurality of linear scratches extends from the first reference point toward the outer peripheral edge and bulges toward one side of the circumference of the outer peripheral edge.

[0008] In a preferred embodiment of the joint structure, the welded portion further has a circular crater portion when viewed in the first direction, and the diameter of the crater portion is smaller than the radius of the outer periphery.

[0009] In a preferred embodiment of the bonded structure, the center of the crater portion when viewed in the first direction is located at the center of a line segment connecting the first reference point and the outer periphery.

[0010] In a preferred embodiment of the joined structure, the plurality of linear scratches are arc-shaped when viewed in the first direction, and the radius of curvature of some of the plurality of linear scratches becomes smaller as they are positioned toward the other side of the circumferential direction.

[0011] In a preferred embodiment of the joined structure, the welded portion includes a bottom portion that overlaps the second metal member when viewed in a second direction that is perpendicular to the first direction.

[0012] In a preferred embodiment of the joint structure, the bottom portion has a circular cross section perpendicular to the first direction.

[0013] A semiconductor device provided by a second aspect of the present disclosure is a semiconductor device including the junction structure provided by the first aspect, and includes an insulating substrate having a main surface and a back surface spaced apart in the first direction, a first conductive member arranged on the main surface, a first switching element conductively joined to the first conductive member, a first terminal including a first terminal portion and electrically connected to the first conductive member, and a second terminal including a second terminal portion and electrically connected to the first switching element.

[0014] In a preferred embodiment of the semiconductor device, the welded portion includes a first joint portion formed across from the first terminal as the first metal member to the first conductive member as the second metal member.

[0015] In a preferred embodiment of the semiconductor device, the first terminal is thinner than the first conductive member.

[0016] In a preferred embodiment of the semiconductor device, the semiconductor device comprises a second conductive member arranged on the main surface and spaced apart from the first conductive member, a second switching element conductively joined to the second conductive member, and a third terminal including a third terminal portion and electrically connected to the second conductive member, and the first conductive member is electrically connected to the second switching element.

[0017] In a preferred embodiment of the semiconductor device, the welded portion includes a second joint portion formed across from the third terminal as the first metal member to the second conductive member as the second metal member.

[0018] In a preferred embodiment of the semiconductor device, the third terminal is thinner than the second conductive member.

[0019] In a preferred embodiment of the semiconductor device, the semiconductor device further includes an insulating member sandwiched between the second terminal portion and the third terminal portion in the first direction, and a portion of the insulating member overlaps the second terminal portion and the third terminal portion when viewed in the first direction.

[0020] In a preferred embodiment of the semiconductor device, the semiconductor device further includes a bus bar having a first supply terminal, a second supply terminal, and an insulator, wherein the second supply terminal is spaced apart from the first supply terminal in the first direction and at least partially overlaps the first supply terminal when viewed in the first direction, the insulator is sandwiched between the first supply terminal and the second supply terminal in the first direction, the first supply terminal is conductively joined to the second terminal portion, and the second supply terminal is conductively joined to the third terminal.

[0021] In a preferred embodiment of the semiconductor device, the semiconductor device further comprises a capacitor connected in parallel to the first supply terminal and the second supply terminal.

[0022] In a preferred embodiment of the semiconductor device, the welded portion includes a third joint portion formed across from the first supply terminal as the first metal member to the second terminal portion as the second metal member.

[0023] In a preferred embodiment of the semiconductor device, the first supply terminal includes a concave tip portion in a region overlapping with the second terminal portion when viewed in the first direction.

[0024] In a preferred embodiment of the semiconductor device, the tip portion includes a base portion and two extension portions extending from the base portion, and the third joint portion is provided on each of the two extension portions and on the base portion, respectively.

[0025] A joining method provided by a third aspect of the present disclosure includes a step of preparing a first metal member, a step of preparing a second metal member and arranging it so that it overlaps the first metal member when viewed in a first direction, and a laser welding step of irradiating the first metal member with laser light in the area where the first metal member and the second metal member overlap to fuse and weld a portion of the first metal member and a portion of the second metal member, wherein the laser welding step includes a first scan in which the laser light is moved along a circular first orbit when viewed in the first direction, and a second scan in which a reference position of the first orbit is moved along a second orbit.

[0026] In a preferred embodiment of the joining method, in the laser welding step, the laser beam is moved by changing the irradiation position of the laser beam using a galvano scanner.

[0027] In a preferred embodiment of the joining method, the first track and the second track are each circular.

[0028] In a preferred embodiment of the joining method, the diameter of the first raceway and the diameter of the second raceway are substantially the same.

[0029] In a preferred embodiment of the above-described joining method, in the second scanning, the laser light is caused to make at least one revolution along the second track.

[0030] In a preferred embodiment of the joining method, in the second scan, before moving the laser light along the second orbit, irradiation of the laser light is started from a center position of the second orbit, and the laser light is moved linearly in a radial direction from the center position of the second orbit.

[0031] In a preferred embodiment of the above-mentioned joining method, the laser light has a beam diameter of 20 μm and a moving speed of 1000 to 1500 mm / s. [Effects of the Invention]

[0032] The bonded structure and bonding method of the present disclosure can suppress surface damage to the two metal members, and the semiconductor device of the present disclosure can suppress performance degradation by suppressing surface damage to the two metal members. [Brief explanation of the drawings]

[0033] [Figure 1] FIG. 1 is a plan view showing a joint structure according to a first embodiment. [Figure 2] FIG. 2 is a cross-sectional view taken along line II-II in FIG. 1, and is a schematic diagram showing the cross-sectional structure of the joined structure. [Figure 3] 1 is a schematic diagram showing a laser welding device used in a joining method according to a first embodiment. [Figure 4] FIG. 3 is a diagram showing the trajectory of a first scan (first trajectory) and the trajectory of a second scan (second trajectory) in the bonding method according to the first embodiment. [Figure 5] FIG. 10 is a diagram showing a movement locus of a laser beam when laser welding is performed. [Figure 6] 1 is a perspective view showing a semiconductor device according to a first embodiment. [Figure 7] 7 is a perspective view of FIG. 6 in which the sealing resin is omitted. [Figure 8] FIG. 1 is a plan view showing a semiconductor device according to a first embodiment. [Figure 9] 9 is a diagram showing the sealing resin in imaginary lines in the plan view shown in FIG. 8. [Figure 10] FIG. 10 is a partially enlarged view of a part of FIG. 9. [Figure 11] FIG. 1 is a front view showing a semiconductor device according to a first embodiment. [Figure 12] FIG. 2 is a bottom view showing the semiconductor device according to the first embodiment. [Figure 13] FIG. 1 is a left side view showing a semiconductor device according to a first embodiment. [Figure 14] FIG. 1 is a right side view showing a semiconductor device according to a first embodiment. [Figure 15] FIG. 10 is a cross-sectional view taken along line XV-XV in FIG. 9. [Figure 16] FIG. 10 is a cross-sectional view taken along line XVI-XVI in FIG. 9. [Figure 17] FIG. 17 is an enlarged cross-sectional view of a main part of FIG. 16. [Figure 18] FIG. 10 is a plan view showing a joint structure according to a modified example. [Figure 19] FIG. 10 is a diagram showing the trajectory of the second scan (second trajectory and third trajectory) in the bonding method according to the modified example. [Figure 20] FIG. 10 is a schematic diagram showing a cross-sectional structure of a joint structure according to a modified example. [Figure 21] FIG. 10 is a perspective view showing a semiconductor device according to a second embodiment. [Figure 22] FIG. 10 is a plan view showing a semiconductor device according to a second embodiment. [Figure 23] FIG. 10 is a bottom view showing the semiconductor device according to the second embodiment. [Figure 24] FIG. 24 is a cross-sectional view taken along line XXIV-XXIV in FIG. 22. [Figure 25] FIG. 10 is a cross-sectional view showing a semiconductor device according to a modified example of the second embodiment. [Figure 26] FIG. 10 is a cross-sectional view showing a semiconductor device according to a modified example of the second embodiment. [Figure 27] FIG. 10 is a perspective view showing a semiconductor device according to a third embodiment. [Figure 28] FIG. 10 is a schematic cross-sectional view illustrating a welded portion according to a modified example. [Figure 29] FIG. 10 is a schematic cross-sectional view illustrating a welded portion according to a modified example. [Figure 30] FIG. 10 is a schematic cross-sectional view illustrating a welded portion according to a modified example. [Figure 31] FIG. 10 is a schematic cross-sectional view illustrating a welded portion according to a modified example. [Figure 32] FIG. 10 is a schematic cross-sectional view illustrating a welded portion according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0034] Preferred embodiments of the bonded structure, semiconductor device, and bonding method of the present disclosure will be described below with reference to the drawings.

[0035] First, a joined structure according to a first embodiment of the present disclosure will be described with reference to FIGS. 1 and 2. The joined structure A1 of the first embodiment includes a first metal member 91, a second metal member 92, and a weld 93. FIG. 1 is a plan view showing the joined structure A1. FIG. 2 is a cross-sectional view taken along line II-II in FIG. 1, and is a schematic diagram showing the cross-sectional structure of the joined structure A1. For ease of explanation, the vertical direction in FIG. 2 is defined as the thickness direction. In other words, the plan view shown in FIG. 1 shows the joined structure A1 as viewed from above to below in the thickness direction.

[0036] The first metal member 91 and the second metal member 92 are, for example, metal plates. The metal plates are made of, for example, copper (Cu) or a Cu alloy. The first metal member 91 is thinner than the second metal member 92. The first metal member 91 has a thickness of, for example, 0.8 mm, and the second metal member 92 has a thickness of, for example, 3.0 mm. The thicknesses of the first metal member 91 and the second metal member 92 are not limited to these values. As shown in FIG. 1, the first metal member 91 and the second metal member 92 partially overlap in a plan view. Furthermore, the first metal member 91 and the second metal member 92 are arranged in contact with each other in the thickness direction, except for the welded portion 93, as shown in FIG. 2. The first metal member 91 is arranged on top of the second metal member 92 (above in FIG. 2).

[0037] As shown in FIG. 2, the welded portion 93 is a portion where a part of the first metal member 91 and a part of the second metal member 92 are fusion-welded. The first metal member 91 and the second metal member 92 are joined by the welded portion 93. As shown in FIG. 1, the welded portion 93 is formed in a region where the first metal member 91 and the second metal member 92 overlap in a plan view. The welded portion 93 is formed by fusing the first metal member 91 and the second metal member 92 by laser welding. Specifically, the welded portion 93 is formed by melting the first metal member 91 and the second metal member 92 due to heat generated by laser irradiation, and then solidifying the melted portion. The welded portion 93 is formed integrally with each of the first metal member 91 and the second metal member 92. In areas other than the welded portion 93, the interface between the first metal member 91 and the second metal member 92 is not joined but is in a state of abutment. The welded portion 93 includes a portion where the materials of the first metal member 91 and the second metal member 92 are alloyed, a portion made up only of the material of the first metal member 91, and a portion made up only of the material of the second metal member 92. For example, the portion near the part where the first metal member 91 and the second metal member 92 were in contact before laser welding is likely to become a portion where the materials of the first metal member 91 and the second metal member 92 are alloyed. In addition, the portion above the welded portion 93 (upper portion in FIG. 2) is likely to become a portion made up only of the material of the first metal member 91.

[0038] 1, the welded portion 93 has, in plan view, an outer peripheral edge 931, a plurality of linear scratches 932, and a crater portion 933. These are weld marks that are formed when the first metal member 91 and the second metal member 92 are laser-welded together.

[0039] The outer peripheral edge 931 is the boundary between the welded portion 93 and the first metal member 91 in a plan view. In a plan view, the outer peripheral edge 931 is annular and has a center at the reference point P1. The outer peripheral edge 931 has a diameter of, for example, 1.6 mm, but is not limited to this. In the example shown in FIG. 1 , the outer peripheral edge 931 is a perfect ring, but is not limited to this, and distortion or zigzags due to laser welding may occur.

[0040] The multiple linear scratches 932 are stripe-like weld scratches formed in the welded portion 93 in a plan view. As shown in FIG. 1 , each linear scratch 932 is arc-shaped in a plan view. Specifically, in a plan view, each linear scratch 932 extends from a reference point P1, which is the center of the outer peripheral edge 931, toward the outer peripheral edge 931, and is curved so as to bulge in one annular direction along the outer peripheral edge 931. In this embodiment, since the outer peripheral edge 931 is annular in a plan view, the annular direction is its circumferential direction. In the example shown in FIG. 1 , each linear scratch 932 is curved so as to bulge in a counterclockwise direction in the circumferential direction of the outer peripheral edge 931.

[0041] Crater portion 933 has, for example, a circular shape in plan view. In plan view, the radius of crater portion 933 is smaller than the radius of outer peripheral edge 931. In plan view, center position P2 of crater portion 933 is located at the center of a line segment connecting the center position of outer peripheral edge 931 (corresponding to reference point P1) and outer peripheral edge 931. In FIG. 1, the line connecting the centers of these line segments is indicated by auxiliary line L1. As shown in FIG. 2, the outer periphery of crater portion 933 protrudes upward.

[0042] As shown in FIG. 2, the welded portion 93 has a cross-sectional structure including an upper portion 934, a body portion 935, and a bottom portion 936.

[0043] 2, the upper portion 934 is a portion of the welded portion 93 that is located on the upper side in the thickness direction. The upper portion 934 protrudes upward from the first metal member 91.

[0044] The body portion 935 is a portion of the welded portion 93 that is sandwiched between the top portion 934 and the bottom portion 936. As shown in Fig. 2, the body portion 935 overlaps the first metal member 91 when viewed in a direction perpendicular to the thickness direction.

[0045] The bottom 936 is a portion of the welded portion 93 that is located on the lower side in the thickness direction. As shown in Fig. 2, the bottom 936 overlaps the second metal member 92 when viewed in a direction perpendicular to the thickness direction. The cross section of the bottom 936 in a plane perpendicular to the thickness direction is, for example, annular.

[0046] Next, a method for forming the joined structure A1 according to the first embodiment of the present disclosure, that is, a method for joining the first metal member 91 and the second metal member 92, will be described with reference to FIGS.

[0047] First, a first metal member 91 and a second metal member 92 are prepared. For example, a metal plate having a thickness of 0.8 mm is prepared as the first metal member 91, and a metal plate having a thickness of 3.0 mm is prepared as the second metal member 92. Then, at least a portion of the first metal member 91 and at least a portion of the second metal member 92 are arranged so as to overlap in the thickness direction (see FIG. 3). At this time, the portions of the first metal member 91 and the second metal member 92 to be joined are arranged so as to overlap in the thickness direction. Then, the first metal member 91 and the second metal member 92 are temporarily fixed together using a clamper (not shown) or the like.

[0048] Next, a laser beam is irradiated onto an area where the first metal member 91 and the second metal member 92 overlap in a plan view, thereby laser welding the first metal member 91 and the second metal member 92. In this embodiment, as shown in FIG. 3, a case will be described in which the laser beam is irradiated from the surface of the first metal member 91 (the upper surface in FIG. 3) to laser weld the first metal member 91 and the second metal member 92 together. In this laser welding step (laser welding step), for example, a YAG laser is used, and the laser welding step is performed by a laser welding device LD (see FIG. 3) described below. The laser welding device LD is used to laser weld the temporarily joined first metal member 91 and second metal member 92 together.

[0049] Fig. 3 shows an example of a laser welding device LD. As shown in Fig. 3, the laser welding device LD includes a laser oscillator 81, an optical fiber 82, and a laser head 83. The laser oscillator 81 oscillates a laser beam. The optical fiber 82 transmits the laser beam oscillated from the laser oscillator 81. The laser head 83 guides the laser beam emitted from the optical fiber 82 to a first metal member 91.

[0050] The laser head 83 includes a collimating lens 831, a mirror 832, a galvano scanner 833, and a condenser lens 834. The collimating lens 831 is a lens that collimates (parallelizes) the laser light emitted from the optical fiber 82. The mirror 832 reflects the laser light collimated by the collimating lens 831 toward the first metal member 91. The galvano scanner 833 is used to change the irradiation position of the laser light on the first metal member 91. The galvano scanner 833 is, for example, a well-known scanner including a pair of movable mirrors (not shown) that can oscillate in two orthogonal directions. The condenser lens 834 condenses the laser light guided from the galvano scanner 833 onto the first metal member 91. In this embodiment, the laser welding device LD is controlled so that the beam diameter of the laser light irradiated onto the first metal member 91 is, for example, about 20 μm, and the moving speed of the laser light is, for example, about 1000 to 1500 mm / s. The peak power of the irradiated laser light is, for example, about 700 to 900 W. The various numerical values ​​described above are merely examples, and the present invention is not limited to these.

[0051] 4 and 5 are diagrams for explaining the trajectory of the laser beam emitted by the laser welding device LD. As described above, the laser welding device LD changes the irradiation position of the laser beam by the galvano scanner 833.

[0052] The laser welding device LD performs a first scan in which the laser beam moves along a circular first trajectory T1 in plan view, and a second scan in which the reference position of the first trajectory T1 moves along a second trajectory T2.

[0053] In the first scan, the laser beam is irradiated so as to trace a circle of radius R3 centered at reference position P3, as shown in Fig. 4. As a result, the trajectory of the laser beam in the first scan becomes a circular first trajectory T1 of radius R3 centered at reference position P3, as shown in Fig. 4. The moving speed of the laser beam along the first trajectory T1 is set to the above-mentioned 1000 to 1500 mm / s.

[0054] In the second scan, as shown in FIG. 4, the reference position P3 in the first scan is moved so as to draw a circle of radius R4 centered on the reference position P4. Therefore, the trajectory of the reference position P3 becomes a circular second trajectory T2 of radius R4 centered on the reference position P4. Here, the radius R3 of the first trajectory T1 and the radius R4 of the second trajectory T2 are set to be approximately the same. The moving speed of the reference position P3 along the second trajectory T2 is set to approximately 5 mm / s. Note that this moving speed is not limited to this. In the second scan, the reference position P3 is moved at least once along the second trajectory T2. In this embodiment, as shown in FIG. 4, after moving once along the second trajectory T2, the laser beam is moved a quarter of the way around. During the one revolution along the second trajectory T2, the power of the laser beam is increased (for example, irradiated at peak power), and the power is gradually reduced during the remaining quarter revolution so as to reach 0 watts at the end of the quarter revolution.

[0055] In the joining method of this embodiment, a laser beam is scanned along a first trajectory T1 as a first scan, while a reference position P3 of the first trajectory T1 is scanned along a second trajectory T2 as a second scan. As a result, the trajectory of the irradiated laser beam in the laser welding process is as shown in FIG. 5. The outer diameter of this trajectory is approximately 1.6 mm. In the joining method of this embodiment, the moving speed of the first scan is approximately 1000 to 1500 mm / s, and the moving speed of the second scan is approximately 5 mm / s. Therefore, as shown in FIG. 5, the trajectory of the laser beam is such that the multiple first trajectories T1 drawn by the first scan partially overlap each other.

[0056] As described above, the laser beam irradiation generates heat in the irradiated portion, melting the first metal member 91. As the first metal member 91 melts, the heat generated by the laser beam diffuses, melting the second metal member 92. As a result, a molten bath is generated in which a portion of the first metal member 91 and a portion of the second metal member 92 are melted. The laser beam irradiation position is then moved, which moves the heat source generated by the laser beam, causing the generated molten bath to cool and solidify. As the molten bath solidifies, the first metal member 91 and the second metal member 92 are fused together, forming a weld 93. Because the first metal member 91 and the second metal member 92 are melted and solidified sequentially as they move along the second trajectory T2, multiple arc-shaped linear scratches 932 are formed in the formed weld 93. Furthermore, the molten bath generated when the laser beam irradiation is stopped solidifies from its periphery, forming a circular crater 933 in the formed weld 93. In this manner, a welded portion 93 spanning the first metal member 91 and the second metal member 92 is formed by laser welding, and the first metal member 91 and the second metal member 92 are joined by the welded portion 93.

[0057] Next, a semiconductor device according to a first embodiment of the present disclosure will be described with reference to FIGS. 6 to 17. A portion of the semiconductor device B1 of the first embodiment is formed by joining two metal members together using the laser welding described above. Therefore, the semiconductor device B1 of the first embodiment has the welded portion 93 and includes the joint structure A1 described above. The semiconductor device B1 includes an insulating substrate 10, a plurality of conductive members 11, a plurality of switching elements 20, two input terminals 31 and 32, an output terminal 33, a pair of gate terminals 34A and 34B, a pair of detection terminals 35A and 35B, a plurality of dummy terminals 36, a pair of side terminals 37A and 37B, a pair of insulating layers 41A and 41B, a pair of gate layers 42A and 42B, a pair of detection layers 43A and 43B, a plurality of base portions 44, a plurality of linear connecting members 51, a plurality of plate-like connecting members 52, a sealing resin 60, and a plurality of welded portions 93. The plurality of switching elements 20 includes a plurality of switching elements 20A and a plurality of switching elements 20B.

[0058] FIG. 6 is a perspective view showing the semiconductor device B1. FIG. 7 is a view in which the sealing resin 60 is omitted from the perspective view shown in FIG. 6. FIG. 8 is a plan view showing the semiconductor device B1. FIG. 9 is a view in which the sealing resin 60 is shown by an imaginary line (two-dot chain line) in the plan view shown in FIG. 8. FIG. 10 is a partially enlarged view of a part of the plan view shown in FIG. 9. FIG. 11 is a front view showing the semiconductor device B1. FIG. 12 is a bottom view showing the semiconductor device B1. FIG. 13 is a side view (left side view) showing the semiconductor device B1. FIG. 14 is a side view (right side view) showing the semiconductor device B1. FIG. 15 is a cross-sectional view taken along line XV-XV in FIG. 9. FIG. 16 is a cross-sectional view taken along line XVI-XVI in FIG. 9. FIG. 17 is an enlarged cross-sectional view of a main part of FIG. 16, showing the cross-sectional structure of the switching element 20.

[0059] For ease of explanation, in Figures 6 to 17, three mutually orthogonal directions are defined as the x-direction, y-direction, and z-direction. The z-direction is the thickness direction of the semiconductor device B1 and corresponds to the thickness direction of the above-mentioned joint structure A1. The x-direction is the left-right direction in the plan view of the semiconductor device B1 (see Figures 8 and 9). The y-direction is the up-down direction in the plan view of the semiconductor device B1 (see Figures 8 and 9). If necessary, one of the x-directions will be referred to as the x1-direction and the other of the x-directions will be referred to as the x2-direction. Similarly, one of the y-directions will be referred to as the y1-direction and the other of the y-directions will be referred to as the y2-direction, one of the z-directions will be referred to as the z1-direction and the other of the z-directions will be referred to as the z2-direction.

[0060] As shown in FIGS. 7, 9, 15, and 16, insulating substrate 10 has a plurality of conductive members 11 arranged thereon. Insulating substrate 10 serves as a support member for the plurality of conductive members 11 and the plurality of switching elements 20. Insulating substrate 10 has electrical insulation properties. The constituent material of insulating substrate 10 is, for example, ceramics with excellent thermal conductivity. An example of such ceramics is AlN (aluminum nitride). In this embodiment, insulating substrate 10 has a rectangular shape in a plan view. As shown in FIGS. 15 and 16, insulating substrate 10 has a main surface 101 and a back surface 102.

[0061] The main surface 101 and the back surface 102 are spaced apart in the z direction and face opposite directions. The main surface 101 faces the side of the z direction where the multiple conductive members 11 are arranged, i.e., the z2 direction. The main surface 101, along with the multiple conductive members 11 and the multiple switching elements 20, is covered with a sealing resin 60. The back surface 102 faces the z1 direction. As shown in FIGS. 12, 15, and 16, the back surface 102 is exposed from the sealing resin 60. For example, a heat sink (not shown) or the like is connected to the back surface 102. The configuration of the insulating substrate 10 is not limited to the example described above, and may be provided individually for each of the multiple conductive members 11.

[0062] Each of the plurality of conductive members 11 is a metal plate. The metal plate is made of, for example, Cu or a Cu alloy. The plurality of conductive members 11, together with the two input terminals 31 and 32 and the output terminal 33, form a conduction path with the plurality of switching elements 20. The plurality of conductive members 11 are arranged on the main surface 101 of the insulating substrate 10 and spaced apart from one another. Each conductive member 11 is bonded to the main surface 101 with a bonding material such as Ag (silver) paste. The dimension of the conductive member 11 in the z direction is, for example, 3.0 mm, but is not limited to this. The plurality of conductive members 11 may be covered with Ag plating.

[0063] The plurality of conductive members 11 include two conductive members 11A and 11B. As shown in FIGS. 7 and 9, the conductive member 11A is positioned further in the x2 direction than the conductive member 11B. The conductive member 11A has a plurality of switching elements 20A mounted thereon. The conductive member 11B has a plurality of switching elements 20B mounted thereon. Each of the two conductive members 11A and 11B has, for example, a rectangular shape in plan view. Each of the conductive members 11A and 11B may have a groove formed in a part of the surface facing the z2 direction. For example, the conductive member 11A may have a groove formed therein extending in the y direction between the plurality of switching elements 20A and an insulating layer 41A (described later) in plan view. Similarly, the conductive member 11B may have a groove formed therein extending in the y direction between the plurality of switching elements 20B and an insulating layer 41B (described later) in plan view.

[0064] Each of the conductive members 11A and 11B includes a roughened surface region in a portion of its surface (the surface facing the z2 direction). Note that in FIGS. 9 and 10, this roughened surface region is indicated by hatching. The roughened surface region is rougher than other portions of the surface of the conductive member 11. The roughened surface region is formed by irradiating the surface of the conductive member 11 with laser light during the manufacturing process of the semiconductor device B1. Specifically, the surface of the conductive member 11 is irradiated with laser light to melt the irradiated portion, and the melted portion solidifies, resulting in a roughened surface. Note that a portion of the irradiated portion may sublimate. The roughened surface region can increase the bonding strength with the sealing resin 60 due to the anchor effect. Each of the conductive members 11A and 11B does not necessarily have to include a roughened surface region.

[0065] The configuration of the plurality of conductive members 11 is not limited to the above example, and may be changed as appropriate depending on the performance required of the semiconductor device B1. For example, the shape, size, and arrangement of each conductive member 11 may be changed based on the number and arrangement of the plurality of switching elements 20.

[0066] Each of the multiple switching elements 20 is a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) made of a semiconductor material mainly composed of SiC (Silicon Carbide). Note that the multiple switching elements 20 are not limited to MOSFETs, and may be field-effect transistors including MISFETs (Metal-Insulator-Semiconductor FETs), bipolar transistors such as IGBTs (Insulated Gate Bipolar Transistors), or IC chips such as LSIs. In this example, each switching element 20 is the same element and is an n-channel MOSFET. Each switching element 20 has, for example, a rectangular shape in a plan view, but is not limited to this.

[0067] As shown in FIG. 17, each of the multiple switching elements 20 has an element main surface 201 and an element back surface 202. FIG. 17 shows switching element 20A. The element main surface 201 and the element back surface 202 are spaced apart in the z direction and face opposite each other. Each element main surface 201 faces the same direction as the main surface 101 of the insulating substrate 10. Each element back surface 202 faces the main surface 101 of the insulating substrate 10.

[0068] As shown in FIG. 17, each of the switching elements 20 has a main surface electrode 21, a back surface electrode 22, and an insulating film 23.

[0069] The principal surface electrode 21 is provided on the element principal surface 201. As shown in FIG. 10 , the principal surface electrode 21 includes a first electrode 211 and a second electrode 212. The first electrode 211 is, for example, a source electrode through which a source current flows. The second electrode 212 is, for example, a gate electrode to which a gate voltage for driving each switching element 20 is applied. The first electrode 211 is larger than the second electrode 212. In the example shown in FIG. 10 , the first electrode 211 is configured as one region, but is not limited to this and may be divided into multiple regions.

[0070] The back surface electrode 22 is provided on the back surface 202 of the element. The back surface electrode 22 is formed, for example, over the entire back surface 202 of the element. The back surface electrode 22 is, for example, a drain electrode through which a drain current flows.

[0071] The insulating film 23 is provided on the element principal surface 201. The insulating film 23 has electrical insulation properties. The insulating film 23 surrounds the principal surface electrode 21 in a plan view. The insulating film 23 is formed by laminating, for example, a SiO2 (silicon dioxide) layer, a SiN4 (silicon nitride) layer, and a polybenzoxazole layer in this order from the element principal surface 201. Note that the insulating film 23 may be a polyimide layer instead of the polybenzoxazole layer.

[0072] As described above, the multiple switching elements 20 include multiple switching elements 20A and multiple switching elements 20B. As shown in FIGS. 7 and 9, the semiconductor device B1 includes four switching elements 20A and four switching elements 20B. The number of multiple switching elements 20 is not limited to this configuration and can be changed as appropriate depending on the performance required of the semiconductor device B1. For example, if the semiconductor device B1 is a half-bridge switching circuit, the multiple switching elements 20A form an upper arm circuit of the semiconductor device B1, and the multiple switching elements 20B form a lower arm circuit of the semiconductor device B1.

[0073] As shown in FIG. 9, each of the multiple switching elements 20A is mounted on a conductive member 11A. The multiple switching elements 20A are arranged in a line at intervals in the y direction. As shown in FIG. 17, each switching element 20A is conductively joined to the conductive member 11A via a conductive bonding layer 29. The material of the conductive bonding layer 29 is, for example, lead-free solder containing Sn (tin) as a main component, but is not limited to this and may be Ag paste. The back surface 202 of each switching element 20A faces the upper surface (surface facing the z2 direction) of the conductive member 11A. The back surface electrode 22 of each switching element 20A is electrically connected to the conductive member 11A via the conductive bonding layer 29.

[0074] As shown in FIG. 9, each of the multiple switching elements 20B is mounted on a conductive member 11B. The multiple switching elements 20B are arranged side by side at intervals in the y direction. Each switching element 20B is conductively joined to the conductive member 11B via a conductive bonding layer 29. The back surface 202 of each switching element 20B faces the upper surface (the surface facing the z2 direction) of the conductive member 11B. The back surface electrode 22 of each switching element 20B is electrically connected to the conductive member 11B via the conductive bonding layer 29.

[0075] The two input terminals 31 and 32 are each a metal plate. The metal plate is made of, for example, Cu or a Cu alloy. The z-direction dimension of each of the two input terminals 31 and 32 is, for example, 0.8 mm, but is not limited to this. As shown in FIG. 11 , the two input terminals 31 and 32 are located closer to the x2 direction in the semiconductor device B1. A power supply voltage, for example, is applied between the two input terminals 31 and 32. The input terminal 31 is a positive electrode (P terminal), and the input terminal 32 is a negative electrode (N terminal). The input terminal 32 is spaced apart from both the input terminal 31 and the conductive member 11A in the z direction.

[0076] As shown in FIGS. 9 and 15, the input terminal 31 has a pad portion 311 and a terminal portion 312.

[0077] The pad portion 311 is a portion of the input terminal 31 that is covered with the sealing resin 60. The end of the pad portion 311 on the x1 direction side is comb-shaped and includes a plurality of comb teeth 311a. Each of the plurality of comb teeth 311a is joined to the surface of the conductive member 11A via some of the welds 93 (specifically, input terminal joints 93B described below), and the input terminal 31 and the conductive member 11A are electrically connected via the welds 93. The comb teeth 311a and the conductive member 11A are joined by laser welding.

[0078] The terminal portion 312 is a portion of the input terminal 31 that is exposed from the sealing resin 60. As shown in Fig. 9 and Fig. 15, the terminal portion 312 extends in the x2 direction from the sealing resin 60 in plan view.

[0079] As shown in FIGS. 9 and 15, the input terminal 32 has a pad portion 321 and a terminal portion 322.

[0080] The pad portion 321 is a portion of the input terminal 32 that is covered with the sealing resin 60. The pad portion 321 includes a connecting portion 321a and multiple extending portions 321b. The connecting portion 321a is strip-shaped and extends in the y direction. The connecting portion 321a is connected to the terminal portion 322. The multiple extending portions 321b are strip-shaped and extend from the connecting portion 321a in the x1 direction. The multiple extending portions 321b are aligned in the y direction and spaced apart from each other in a plan view. The surface of each extending portion 321b facing the z1 direction is in contact with the corresponding base portion 44, and the extending portion 321b is supported by the conductive member 11A via the corresponding base portion 44.

[0081] The pad portion 321 includes a roughened region on part of its surface. In FIG. 9, this roughened region is indicated by hatching. The roughened region is rougher than other portions of the surface of the pad portion 321. The roughened region is formed by irradiating the surface of the input terminal 32 with laser light during the manufacturing process of the semiconductor device B1. This roughened region can increase the bonding strength with the sealing resin 60 due to the anchor effect. The pad portion 321 does not necessarily have to include a roughened region.

[0082] The terminal portion 322 is a portion of the input terminal 32 that is exposed from the sealing resin 60. As shown in FIGS. 9 and 15, the terminal portion 322 extends in the x2 direction from the sealing resin 60 in a plan view. The terminal portion 322 has a rectangular shape in a plan view. As shown in FIGS. 9 and 15, the terminal portion 322 overlaps the terminal portion 312 of the input terminal 31 in a plan view. The terminal portion 322 is spaced apart from the terminal portion 312 in the z2 direction. In the examples shown in FIGS. 9 and 15, the shape of the terminal portion 322 is the same as the shape of the terminal portion 312.

[0083] The output terminal 33 is a metal plate. The metal plate is made of, for example, Cu or a Cu alloy. As shown in FIG. 11 , the output terminal 33 is located near the x1 direction in the semiconductor device B1. AC power (voltage) converted by the multiple switching elements 20 is output from the output terminal 33.

[0084] As shown in FIGS. 9 and 15, the output terminal 33 includes a pad portion 331 and a terminal portion 332.

[0085] The pad portion 331 is a portion of the output terminal 33 that is covered with the sealing resin 60. The portion of the pad portion 331 on the x2 direction side is comb-shaped and includes a plurality of comb-tooth portions 331a. Each of the plurality of comb-tooth portions 331a is joined to the surface of the conductive member 11B via some of the welds 93 (specifically, output terminal joint portions 93A described below), and the output terminal 33 and the conductive member 11B are electrically connected via the welds 93. The comb-tooth portions 331a and the conductive member 11B are joined by laser welding.

[0086] The pad portion 331 includes a roughened region on a part of its surface. In FIG. 9, this roughened region is indicated by hatching. The roughened region is rougher than other portions of the surface of the pad portion 331. The roughened region is formed by irradiating the surface of the output terminal 33 with laser light during the manufacturing process of the semiconductor device B1. This roughened region can increase the bonding strength with the sealing resin 60 due to the anchor effect. The pad portion 331 does not necessarily have to include a roughened region.

[0087] The terminal portion 332 is a portion of the output terminal 33 that is exposed from the sealing resin 60. As shown in FIGS. 9 and 15, the terminal portion 332 extends from the sealing resin 60 in the x1 direction.

[0088] 8 to 10 and 12, the pair of gate terminals 34A, 34B are located adjacent to the respective conductive members 11A, 11B in the y direction. A gate voltage for driving the plurality of switching elements 20A is applied to the gate terminal 34A. A gate voltage for driving the plurality of switching elements 20B is applied to the gate terminal 34B.

[0089] As shown in FIGS. 9 and 10, each of the pair of gate terminals 34A, 34B has a pad portion 341 and a terminal portion 342. In each of the gate terminals 34A, 34B, the pad portion 341 is covered with sealing resin 60. As a result, each of the gate terminals 34A, 34B is supported by the sealing resin 60. The surface of each pad portion 341 may be plated with Ag, for example. Each of the terminal portions 342 is connected to each of the pad portions 341 and is exposed from the sealing resin 60. Each of the terminal portions 342 is L-shaped when viewed in the x direction.

[0090] 8 to 10 and 12, the pair of detection terminals 35A, 35B are located adjacent to the pair of gate terminals 34A, 34B in the x direction. The detection terminal 35A detects a voltage (a voltage corresponding to a source current) applied to each principal surface electrode 21 (first electrode 211) of the multiple switching elements 20A. The detection terminal 35B detects a voltage (a voltage corresponding to a source current) applied to each principal surface electrode 21 (first electrode 211) of the multiple switching elements 20B.

[0091] As shown in FIGS. 9 and 10 , each of the pair of detection terminals 35A, 35B has a pad portion 351 and a terminal portion 352. In each of the detection terminals 35A, 35B, the pad portion 351 is covered with sealing resin 60. As a result, each of the detection terminals 35A, 35B is supported by the sealing resin 60. The surface of each pad portion 351 may be plated with Ag, for example. Each of the terminal portions 352 is connected to each of the pad portions 351 and is exposed from the sealing resin 60. Each of the terminal portions 352 is L-shaped when viewed in the x direction.

[0092] As shown in FIGS. 8 to 10 and 12, the multiple dummy terminals 36 are located on the opposite side of the pair of gate terminals 34A, 34B from the pair of detection terminals 35A, 35B in the x direction. In this embodiment, there are six dummy terminals 36. Of these, three dummy terminals 36 are located on one side of the x direction (x2 direction). The remaining three dummy terminals 36 are located on the other side of the x direction (x1 direction). The number of multiple dummy terminals 36 is not limited to this configuration. Also, a configuration without multiple dummy terminals 36 may be used.

[0093] As shown in FIGS. 9 and 10 , each of the multiple dummy terminals 36 has a pad portion 361 and a terminal portion 362. The pad portion 361 of each dummy terminal 36 is covered with the sealing resin 60. Thus, each dummy terminal 36 is supported by the sealing resin 60. The surface of each pad portion 361 may be plated with Ag, for example. Each terminal portion 362 is connected to the corresponding pad portion 361 and is exposed from the sealing resin 60. Each terminal portion 362 is L-shaped when viewed in the x-direction. In the examples shown in FIGS. 6 to 14 , the shape of each terminal portion 362 is the same as the shape of each terminal portion 342 of the pair of gate terminals 34A and 34B and the shape of each terminal portion 352 of the pair of detection terminals 35A and 35B.

[0094] 7, 9, and 16, the pair of side terminals 37A, 37B are located at edge portions on the y1-direction side of the sealing resin 60 in plan view, and are arranged at respective edge portions in the x-direction of the sealing resin 60. As shown in FIGS. 9 and 16, each of the pair of side terminals 37A, 37B has a pad portion 371 and an end face 372.

[0095] In each of the side terminals 37A and 37B, the pad portion 371 is covered with the sealing resin 60. As shown in FIG. 9, a portion of each pad portion 371 is bent in a plan view. As shown in FIG. 16, another portion of each pad portion 371 is bent in the z-direction. The pad portion 371 of the side terminal 37A is joined to the conductive member 11A via a portion of the welded portion 93 (specifically, a side terminal joint portion 93D described later), and the pad portion 371 of the side terminal 37B is joined to the conductive member 11B via a portion of the welded portion 93 (specifically, a side terminal joint portion 93C described later). As a result, the side terminal 37A is supported by the conductive member 11A, and the side terminal 37B is supported by the conductive member 11B.

[0096] Each pad portion 371 includes a roughened surface region in a portion of its surface. In FIG. 9, this roughened surface region is indicated by hatching. The roughened surface region is rougher than other portions of the surface of each pad portion 371. The roughened surface region is formed by irradiating the surfaces of the pair of side terminals 37A, 37B with laser light during the manufacturing process of the semiconductor device B1. This roughened surface region can increase the bonding strength with the sealing resin 60 due to the anchor effect. Each side terminal 37A, 37B does not necessarily have to include a roughened surface region.

[0097] In each of the side terminals 37A, 37B, an end face 372 is exposed from the sealing resin 60. The end face 372 of the side terminal 37A faces in the x2 direction and is, for example, substantially flush with the resin side face 631. However, it does not have to be flush. The end face 372 of the side terminal 37B faces in the x1 direction and is, for example, substantially flush with the resin side face 632. However, it does not have to be flush. In a plan view, each of the side terminals 37A, 37B overlaps the sealing resin 60.

[0098] The configuration of each of the side terminals 37A, 37B is not limited to the above example. For example, in a plan view, the side terminals 37A, 37B may extend so as to protrude from the resin side surfaces 631, 632, respectively. Furthermore, the semiconductor device B1 may not necessarily include each of the side terminals 37A, 37B.

[0099] 8 to 10, the pair of gate terminals 34A, 34B, the pair of detection terminals 35A, 35B, and the plurality of dummy terminals 36 are arranged along the x direction in a plan view. In the semiconductor device B1, the pair of gate terminals 34A, 34B, the pair of detection terminals 35A, 35B, the plurality of dummy terminals 36, and the pair of side terminals 37A, 37B are all formed from the same lead frame.

[0100] The insulating member 39 has electrical insulation properties and is made of, for example, insulating paper. A portion of the insulating member 39 is a flat plate, and as shown in FIG. 15 , is sandwiched in the z direction between the terminal portion 312 of the input terminal 31 and the terminal portion 322 of the input terminal 32. In a plan view, the entire input terminal 31 overlaps the insulating member 39. In addition, in a plan view, a portion of the pad portion 321 and the entire terminal portion 322 of the input terminal 32 overlap the insulating member 39. The two input terminals 31 and 32 are insulated from each other by the insulating member 39. A portion of the insulating member 39 (the portion on the x1 direction side) is covered with sealing resin 60.

[0101] 15, the insulating member 39 has an intervening portion 391 and an extending portion 392. The intervening portion 391 is interposed in the z direction between the terminal portion 312 of the input terminal 31 and the terminal portion 322 of the input terminal 32. The intervening portion 391 is entirely sandwiched between the terminal portion 312 and the terminal portion 322. The extending portion 392 extends from the intervening portion 391 in the x2 direction further than the terminal portion 312 and the terminal portion 322.

[0102] The pair of insulating layers 41A, 41B have electrical insulation properties and are made of, for example, glass epoxy resin. As shown in FIG. 9, each of the pair of insulating layers 41A, 41B has a strip shape extending in the y direction. As shown in FIGS. 9, 10, 15, and 16, the insulating layer 41A is bonded to the upper surface (surface facing the z2 direction) of the conductive member 11A. The insulating layer 41A is located further in the x2 direction than the multiple switching elements 20A. As shown in FIGS. 9, 10, 15, and 16, the insulating layer 41B is bonded to the surface (surface facing the z2 direction) of the conductive member 11B. The insulating layer 41B is located further in the x1 direction than the multiple switching elements 20B.

[0103] The pair of gate layers 42A, 42B are conductive and are made of, for example, Cu. As shown in FIG. 9, each of the pair of gate layers 42A, 42B has a strip shape extending in the y direction. As shown in FIGS. 9, 10, 15, and 16, the gate layer 42A is disposed on an insulating layer 41A. The gate layer 42A is electrically connected to the second electrode 212 (gate electrode) of each switching element 20A via a linear connecting member 51 (specifically, a gate wire 511, which will be described later). The gate layer 42B is disposed on an insulating layer 41B as shown in FIGS. 9, 10, 15, and 16. The gate layer 42B is electrically connected to the second electrode 212 (gate electrode) of each switching element 20B via a linear connecting member 51 (specifically, a gate wire 511, which will be described later).

[0104] The pair of detection layers 43A, 43B are conductive and made of, for example, Cu. As shown in FIG. 9, each of the pair of detection layers 43A, 43B has a strip shape extending in the y direction. As shown in FIGS. 9, 10, 15, and 16, the detection layer 43A is disposed on the insulating layer 41A together with the gate layer 42A. The detection layer 43A is disposed adjacent to the gate layer 42A on the insulating layer 41A and is spaced apart from the gate layer 42A. The detection layer 43A is disposed, for example, on the side (x2 direction) where the multiple switching elements 20A are disposed relative to the gate layer 42A, but may be disposed on the opposite side. The detection layer 43A is electrically connected to the first electrode 211 (source electrode) of each switching element 20A via a linear connecting member 51 (specifically, a detection wire 512, described later). As shown in FIGS. 9, 10, 15, and 16, the detection layer 43B is disposed on the insulating layer 41B together with the gate layer 42B. The detection layer 43B is located adjacent to the gate layer 42B on the insulating layer 41B and is spaced apart from the gate layer 42B. The detection layer 43B is located, for example, on the side (x1 direction) where the multiple switching elements 20B are disposed relative to the gate layer 42B, but may also be located on the opposite side. The detection layer 43B is electrically connected to the first electrodes 211 (source electrodes) of each switching element 20B via linear connecting members 51 (specifically, detection wires 512, described later).

[0105] Each of the base portions 44 has electrical insulation properties and is made of, for example, ceramic. As shown in FIGS. 7 and 15 , each base portion 44 is bonded to the surface of the conductive member 11A. Each base portion 44 has, for example, a rectangular shape in plan view. The base portions 44 are aligned in the y direction and spaced apart from one another. The z-direction dimension of each base portion 44 is approximately the same as the sum of the z-direction dimension of the input terminal 31 and the z-direction dimension of the insulating member 39. Each base portion 44 is bonded to the extension portion 321b of the pad portion 321 of the input terminal 32. Each base portion 44 supports the input terminal 32.

[0106] The plurality of linear connecting members 51 are so-called bonding wires. Each of the plurality of linear connecting members 51 is conductive and is made of, for example, aluminum (Al), gold (Au), or copper (Cu). As shown in FIGS. 9 and 10 , the plurality of linear connecting members 51 include a plurality of gate wires 511, a plurality of detection wires 512, a pair of first connecting wires 513, and a pair of second connecting wires 514.

[0107] 9 and 10, one end of each of the plurality of gate wires 511 is joined to the second electrode 212 (gate electrode) of the switching element 20, and the other end is joined to one of the pair of gate layers 42A, 42B. Among the plurality of gate wires 511, there are those that connect the second electrode 212 of the switching element 20A to the gate layer 42A and those that connect the second electrode 212 of the switching element 20B to the gate layer 42B.

[0108] 9 and 10, one end of each of the plurality of detection wires 512 is joined to the first electrode 211 (source electrode) of the switching element 20, and the other end is joined to one of the pair of detection layers 43A, 43B. The plurality of detection wires 512 include one that connects the first electrode 211 of the switching element 20A to the detection layer 43A, and one that connects the first electrode 211 of the switching element 20B to the detection layer 43B.

[0109] 9 and 10, one of the pair of first connecting wires 513 connects the gate layer 42A and the gate terminal 34A, and the other connects the gate layer 42B and the gate terminal 34B. One of the first connecting wires 513 has one end bonded to the gate layer 42A and the other end bonded to the pad portion 341 of the gate terminal 34A, providing electrical continuity therebetween. The other first connecting wire 513 has one end bonded to the gate layer 42B and the other end bonded to the pad portion 341 of the gate terminal 34B, providing electrical continuity therebetween.

[0110] 9 and 10, one of the pair of second connecting wires 514 connects the detection layer 43A and the detection terminal 35A, and the other connects the detection layer 43B and the detection terminal 35B. One second connecting wire 514 has one end joined to the detection layer 43A and the other end joined to the pad portion 351 of the detection terminal 35A, providing electrical continuity therebetween. The other second connecting wire 514 has one end joined to the detection layer 43B and the other end joined to the pad portion 351 of the detection terminal 35B, providing electrical continuity therebetween.

[0111] Each of the plurality of plate-shaped connecting members 52 is electrically conductive and is made of, for example, Al, Au, or Cu. Each plate-shaped connecting member 52 can be formed by bending a metal plate. As shown in FIGS. 7, 9, and 10, the plurality of plate-shaped connecting members 52 include a plurality of first leads 521 and a plurality of second leads 522. Bonding wires equivalent to the linear connecting members 51 may be used instead of the plurality of plate-shaped connecting members 52.

[0112] 7, 9, and 10, each of the multiple first leads 521 connects the switching element 20A and the conductive member 11B. One end of each first lead 521 is joined to the first electrode 211 (source electrode) of the switching element 20A, and the other end is joined to the surface of the conductive member 11B.

[0113] 7, 9, and 10, each of the plurality of second leads 522 connects a corresponding switching element 20B to the input terminal 32. One end of each second lead 522 is joined to the first electrode 211 (source electrode) of the corresponding switching element 20B, and the other end is joined to a corresponding extension portion 321b of the pad portion 321 of the input terminal 32. Each second lead 522 is joined by, for example, Ag paste or solder. Each second lead 522 is bent in the z direction.

[0114] As shown in Figures 15 and 16, the sealing resin 60 covers the insulating substrate 10 (excluding the back surface 102), the plurality of conductive members 11, the plurality of switching elements 20, the plurality of linear connecting members 51, and the plurality of plate-like connecting members 52. The constituent material of the sealing resin 60 is, for example, epoxy resin. As shown in Figures 6, 8, 9, and 11 to 14, the sealing resin 60 has a resin main surface 61, a resin back surface 62, and a plurality of resin side surfaces 63.

[0115] The resin main surface 61 and the resin back surface 62 are spaced apart in the z direction and face opposite each other. The resin main surface 61 faces the z2 direction, and the resin back surface 62 faces the z1 direction. As shown in FIG. 12 , the resin back surface 62 has a frame shape surrounding the back surface 102 of the insulating substrate 10 in a plan view. Each of the multiple resin side surfaces 63 is connected to both the resin main surface 61 and the resin back surface 62 and is sandwiched between them. The multiple resin side surfaces 63 include a pair of resin side surfaces 631, 632 spaced apart in the x direction and a pair of resin side surfaces 633, 634 spaced apart in the y direction. The resin side surface 631 faces the x2 direction, and the resin side surface 632 faces the x1 direction. The resin side surface 633 faces the y2 direction, and the resin side surface 634 faces the y1 direction.

[0116] 6, 11, and 12, the sealing resin 60 includes a plurality of recesses 65 each recessed in the z direction from the resin rear surface 62. Each of the recesses 65 extends in the y direction and is connected from the edge of the resin rear surface 62 in the y1 direction to the edge of the resin rear surface 62 in the y2 direction in plan view. The recesses 65 are formed in groups of three on either side of the rear surface 102 of the insulating substrate 10 in the x direction in plan view. The sealing resin 60 does not necessarily have to have a plurality of recesses 65.

[0117] Each of the plurality of welds 93 is a portion that joins two metal members and has the same structure as each of the welds 93 of the above-described joined structure A1 (see FIGS. 1 and 2). The plurality of welds 93 includes a plurality of output terminal joints 93A, a plurality of input terminal joints 93B, and two side terminal joints 93C and 93D.

[0118] 9 and 15, the plurality of output terminal joints 93A are formed by laser welding a part of the output terminal 33 and a part of the conductive member 11B that overlap in a plan view. In a plan view, the plurality of output terminal joints 93A are formed one by one on each of the comb-tooth portions 331a of the pad portion 331 of the output terminal 33. Each output terminal joint 93A joins the output terminal 33 as the first metal member 91 and the conductive member 11B as the second metal member 92, forming a joint structure A1.

[0119] 9 and 15, the plurality of input terminal joints 93B are formed by laser welding a part of the input terminal 31 and a part of the conductive member 11A that overlap in a plan view. In a plan view, the plurality of input terminal joints 93B are formed one for each of the comb-tooth portions 311a of the pad portion 311 of the input terminal 31. Each input terminal joint 93B joins the input terminal 31 as the first metal member 91 and the conductive member 11A as the second metal member 92, forming a joint structure A1.

[0120] 9 and 16, the side terminal joint 93C is formed by laser welding a part of the side terminal 37A and a part of the conductive member 11A that overlap in a plan view. In a plan view, the side terminal joint 93C is formed on the pad portion 371 of the side terminal 37A. The side terminal joint 93C joins the side terminal 37A as the first metal member 91 and the conductive member 11A as the second metal member 92, forming a joined structure A1.

[0121] 9 and 16, the side terminal joint 93D is formed by laser welding a portion of the side terminal 37B and a portion of the conductive member 11B that overlap in a plan view. The side terminal joint 93D is formed on the pad portion 371 of the side terminal 37B in a plan view. The side terminal joint 93D joins the side terminal 37B as the first metal member 91 and the conductive member 11B as the second metal member 92, forming a joined structure A1.

[0122] Next, the effects of the joined structure A1, the joining method, and the semiconductor device B1 according to the first embodiment will be described.

[0123] The joined structure A1 has a welded portion 93. The welded portion 93 is formed by fusion welding a portion of the first metal member 91 and a portion of the second metal member 92 in an area where the first metal member 91 and the second metal member 92 overlap. The welded portion 93 is formed by, for example, laser welding, and joins the first metal member 91 and the second metal member 92. Therefore, the first metal member 91 and the second metal member 92 do not rub against each other. This makes it possible to suppress surface damage to the first metal member 91 and the second metal member 92.

[0124] In the joining method of this embodiment, a laser beam is scanned along a first trajectory T1, and a reference position P3 of the first trajectory T1 is scanned along a second trajectory T2. It is known that in laser welding, spattering can be suppressed by increasing the laser beam irradiation speed and reducing the laser beam diameter. However, increasing the laser beam irradiation speed and reducing the laser beam diameter can cause a problem in which heat generated by the laser beam is not transferred from the first metal member 91 to the second metal member 92. As a result, the second metal member 92 may not melt, and a weld 93 may not be formed across the first metal member 91 and the second metal member 92. This means that the first metal member 91 and the second metal member 92 are not joined. Therefore, by performing the first and second scans described above, the trajectory of the laser beam is set to, for example, the trajectory shown in FIG. 5 . As a result, even if the irradiation speed of the laser beam is increased and the beam diameter of the laser beam is reduced, the heat generated by the laser beam can be sufficiently transmitted from the first metal member 91 to the second metal member 92. As described above, the joining method of this embodiment can suppress the generation of spatter during laser welding and can join the first metal member 91 and the second metal member 92.

[0125] In the joining method of this embodiment, the radius R3 of the first trajectory T1 and the radius R4 of the second trajectory T2 are substantially the same. For example, if the radius R3 of the first trajectory T1 and the radius R4 of the second trajectory T2 are different, the trajectory of the laser light (see FIG. 5) will not pass through the central portion in plan view (near the reference position P4 of the second trajectory T2). Therefore, by making the radius R3 of the first trajectory T1 and the radius R4 of the second trajectory T2 substantially the same, the trajectory of the laser light can be made to pass through the central portion in plan view, as shown in FIG. 5.

[0126] The semiconductor device B1 includes multiple welds 93. Specifically, the metal members with the welds 93 are joined by laser welding. Therefore, friction between the metal members does not occur. In the ultrasonic bonding described above, the two metal members being joined are rubbed against each other, which can generate dust due to wear of the metal members. If this dust occurs during the manufacturing process of the semiconductor device B1, it can cause malfunction of the semiconductor device B1. Therefore, by joining the two metal members by laser welding, malfunction of the semiconductor device B1 can be suppressed. Furthermore, laser welding tends to locally diffuse heat generated during welding. For example, when the pad portion 331 of the output terminal 33 and the conductive member 11B are joined by laser welding, the heat generated by this laser welding does not diffuse to the conductive bonding layer 29 formed on the conductive member 11B. Therefore, diffusion of heat to the conductive bonding layer 29 and other layers is suppressed. Therefore, unintended melting of the conductive bonding layer 29 and other layers during the manufacturing process of the semiconductor device B1 can be suppressed, thereby suppressing bonding defects of the multiple switching elements 20.

[0127] In the semiconductor device B1, a plurality of welds 93 are formed by the above-described joining method. As described above, this joining method can suppress the occurrence of spatter. If spatter occurs during the manufacturing process of the semiconductor device B1, it may cause malfunction of the semiconductor device B1. Therefore, by forming a plurality of welds 93 by the above-described joining method, it is possible to suppress malfunction of the semiconductor device B1.

[0128] The semiconductor device B1 includes an insulating member 39 between the terminal portion 312 of the input terminal 31 and the terminal portion 322 of the input terminal 32 in the z direction. This allows the terminal portion 312 and the terminal portion 322 to be easily laminated together.

[0129] In the joined structure A1 according to the first embodiment, as shown in FIG. 1, all of the linear scratches 932 have the same radius of curvature. However, this is not limiting. For example, the radius of curvature of the linear scratches 932 may not be the same. FIG. 18 shows an example of such a modification. In the example shown in FIG. 18, the radius of curvature of some of the linear scratches 932 gradually decreases as the position increases in a predetermined circumferential direction (clockwise in FIG. 18) of the outer circumferential edge 931. The smallest radius of curvature of the linear scratches 932 is, for example, approximately the same as the radius of curvature of the crater portion 933. Note that the predetermined direction coincides with the movement direction of the second track T2. For example, such weld marks can be formed depending on the ease of melting the first metal member 91 and the second metal member 92, the degree of diffusion of heat generated by the laser beam, and other factors.

[0130] In the welding method according to the first embodiment, the second trajectory T2 in the second scan is circular in plan view. However, the second trajectory T2 is not limited to this. For example, the reference position P3 may be moved linearly, curvilinearly, elliptically, or polygonally in plan view. However, even in this case, the first scan involves circular movement based on the reference position P3. When the reference position P3 is moved elliptically, the circular direction in the present disclosure refers to the direction of an elliptical trajectory. Furthermore, the second trajectory T2 may be moved along multiple shapes rather than just one shape. FIG. 19 illustrates an example where linear and circular movements are combined. In the example shown in FIG. 19, the reference position P3 of the first trajectory T1 is moved linearly from the center position of the second trajectory T2 (corresponding to the reference position P4) toward the second trajectory T2 in the radial direction of the second trajectory T2 (see the third trajectory T3). Thereafter, the reference position P3 is moved along the second trajectory T2 in the same manner as in the example described above. The peak power of the irradiated laser beam may be controlled to be the same or different while the reference position P3 is moved along the third trajectory T3 and while the reference position P3 is moved one revolution along the second trajectory T2. When the second scan is performed by combining multiple trajectories in this manner, the welded portion 93 has a structure as shown in FIG. 20. The welded portion 93 shown in FIG. 20 has a bottom 936 with a different shape from the welded portion 93 of the first embodiment. Specifically, the cross section of the bottom 936 taken along a plane perpendicular to the thickness direction is circular rather than annular. The welded portion 93 shown in FIG. 20 not only has high joint strength but also contributes to low resistance by widening the conduction path.

[0131] Next, a semiconductor device according to a second embodiment will be described with reference to Figures 21 to 24. In the following description, elements that are the same as or similar to those in the first embodiment will be given the same reference numerals and descriptions thereof will be omitted.

[0132] The semiconductor device B2 of the second embodiment differs from the semiconductor device B1 mainly in the following respects: it further includes a bus bar C1, and the plurality of welds 93 further include a plurality of supply terminal joints 93E and a plurality of supply terminal joints 93F. The semiconductor device B2 includes the semiconductor device B1 and the bus bar C1 connected to the semiconductor device B1 via a plurality of supply terminal joints 93E and a plurality of supply terminal joints 93F. FIG. 21 is a perspective view showing the semiconductor device B2. FIG. 22 is a plan view showing the semiconductor device B2. FIG. 23 is a bottom view showing the semiconductor device B2. FIG. 24 is a cross-sectional view taken along line XXIV-XXIV in FIG. 22.

[0133] As shown in FIGS. 21 to 24, the bus bar C1 includes two supply terminals 71 and 72, an insulator 73, and a molding resin 74.

[0134] Each of the two supply terminals 71, 72 is a metal plate. The metal plate is made of, for example, Cu or a Cu alloy. As shown in FIGS. 21 to 24, each of the supply terminals 71, 72 has a strip shape extending in the x direction. The supply terminal 72 is arranged apart from the supply terminal 71 on the side facing the main surface 101 of the insulating substrate 10 in the z direction. In a plan view, the supply terminal 72 overlaps the supply terminal 71. In the examples shown in FIGS. 22 to 24, the shape of the supply terminal 71 and the shape of the supply terminal 72 are the same. The dimension of each of the supply terminals 71, 72 in the z direction is, for example, 0.8 mm, but is not limited to this.

[0135] As shown in FIG. 24 , the supply terminal 71 is joined to the input terminal 31 by laser welding and is electrically connected to the input terminal 31. The supply terminal 71 includes a base 711 and multiple extensions 712 at a tip portion exposed from the molded resin 74. The multiple extensions 712 extend from the base 711 in the x1 direction. Each extension 712 has a rectangular shape in a plan view. In this embodiment, the supply terminal 71 includes two extensions 712. The two extensions 712 are arranged with a gap between them in the y direction. As a result, the tip portion of the supply terminal 71 has a concave shape. Note that the shape of the supply terminal 71 is not limited to the above. For example, the portion exposed from the molded resin 74 may have a rectangular shape in a plan view.

[0136] As shown in FIG. 24 , the supply terminal 72 is joined to the input terminal 32 by laser welding and is electrically connected to the input terminal 32. The supply terminal 72 includes a base 721 and multiple extensions 722 at the tip end exposed from the molded resin 74. The multiple extensions 722 extend from the base 721 in the x1 direction. Each extension 722 has a rectangular shape in a plan view. In this embodiment, there are two extensions 722. The two extensions 722 are arranged with a gap between them in the y direction. As a result, the tip end of the supply terminal 72 has a concave shape. Note that the shape of the supply terminal 72 is not limited to the one described above. For example, the portion exposed from the molded resin 74 may have a rectangular shape in a plan view.

[0137] As shown in Fig. 24, insulator 73 is sandwiched between two supply terminals 71 and 72 in the z direction. Insulator 73 has electrical insulation properties, and an example of a constituent material thereof is a synthetic resin such as glass epoxy resin. The surface of supply terminal 71 facing the z2 direction is in contact with insulator 73. The surface of supply terminal 72 facing the z1 direction is in contact with insulator 73. Supply terminal 71 and supply terminal 72 overlap each other in a plan view and form laminated wiring that is electrically insulated from each other by insulator 73.

[0138] As shown in Fig. 24, the molded resin 74 covers a portion of each of the supply terminals 71 and 72 and the insulator 73. The molded resin 74 is made of an electrically insulating synthetic resin such as epoxy resin. A portion of each of the supply terminals 71 and 72 and the insulator 73 protrudes from both sides of the molded resin 74 in the x direction. Note that the bus bar C1 does not necessarily have to include the molded resin 74.

[0139] As shown in FIGS. 23 and 24 , the multiple supply terminal joints 93E are formed by laser welding a portion of the supply terminal 71 and a portion of the input terminal 31 that overlap in plan view. Each supply terminal joint 93E joins the supply terminal 71 as the first metal member 91 to the input terminal 31 as the second metal member 92, forming a joint structure A1. In the example shown in FIG. 23 , there are three supply terminal joints 93E, but the number of supply terminal joints 93E is not particularly limited. In the joint structure A1 including each supply terminal joint 93E, the second metal member 92 is thinner than each of the joint structures A1 according to the first embodiment.

[0140] As shown in FIG. 23 , among the multiple supply terminal joints 93E, those formed on the extensions 712 of the supply terminals 71 have a larger radius in plan view (corresponding to the radius of the outer circumferential edges 931) than those formed on the bases 711 of the supply terminals 71. This occurs because the width (dimension in the y direction) of the extensions 712 is narrower than the width (dimension in the y direction) of the bases 711. More specifically, because the width of the extensions 712 is narrower than the width of the bases 711, heat generated during laser welding is less likely to dissipate. As a result, the molten bath generated becomes larger, and the diameter of the supply terminal joints 93E formed on the extensions 712 becomes larger. In consideration of this tendency, various conditions of laser welding (e.g., the peak power of the laser beam) may be adjusted to make the radii of all the supply terminal joints 93E in plan view approximately the same.

[0141] As shown in FIGS. 21 to 22 and 24, the plurality of supply terminal joints 93F are formed by laser welding together parts of the supply terminals 72 and parts of the input terminals 32 that overlap in plan view. Each supply terminal joint 93F joins a supply terminal 72 as a first metal member 91 to an input terminal 32 as a second metal member 92, forming a joint structure A1. In this embodiment, there are three supply terminal joints 93F. In the example shown in FIG. 22, the number of supply terminal joints 93F is not particularly limited. In a joint structure A1 including each supply terminal joint 93F, the second metal member 92 is thinner than the joint structures A1 according to the first embodiment.

[0142] As shown in FIG. 22 , among the multiple supply terminal joints 93F, those formed on the extensions 722 of the supply terminals 72 have a larger radius in plan view (corresponding to the radius of the outer circumferential edges 931) than those formed on the bases 721 of the supply terminals 72. This occurs because the width (y-direction dimension) of the extensions 722 is narrower than the width of the bases 721 (y-direction dimension). More specifically, because the width of the extensions 722 is narrower than the width of the bases 721, heat generated during laser welding is less likely to dissipate. As a result, the molten bath generated becomes larger, and the diameter of the supply terminal joints 93F formed on the extensions 722 becomes larger. In consideration of this tendency, the radii of the supply terminal joints 93F in plan view may be made approximately the same by adjusting various laser welding conditions (e.g., the peak power of the laser beam).

[0143] In the semiconductor device B2, the supply terminal 71 is positive and the supply terminal 72 is negative. The two supply terminals 71 and 72 are connected to a direct-current power source DC on the x2 direction side, for example, as shown in Fig. 24. This allows the power supply voltage of the direct-current power source DC to be applied between the two input terminals 31 and 32 via the bus bar C1.

[0144] Next, the functions and effects of the semiconductor device B2 according to the second embodiment will be described.

[0145] The semiconductor device B2 has a plurality of welds 93. That is, similar to the first embodiment, the metal members on which the welds 93 are formed are joined by laser welding. Therefore, the two metal members do not rub against each other, which makes it possible to suppress the generation of dust. This makes it possible to suppress malfunctions of the semiconductor device B2. Furthermore, since the welds 93 are formed by the above-mentioned joining method, it is possible to suppress the generation of spatter. This makes it possible to suppress malfunctions of the semiconductor device B2.

[0146] The semiconductor device B2 includes an input terminal 31 and an input terminal 32. The input terminal 31 includes a terminal portion 312. The input terminal 32 includes a terminal portion 322. The semiconductor device B2 also includes a bus bar C1. The bus bar C1 includes two supply terminals 71 and 72. The terminal portion 322 of the input terminal 32 is spaced apart from the terminal portion 312 of the input terminal 31 in the z direction and overlaps with the terminal portion 312 of the input terminal 31 in a planar view. The supply terminal 72 is spaced apart from the supply terminal 71 in the z direction and overlaps with the supply terminal 71 in a planar view. The supply terminal 71 and the terminal portion 312 of the input terminal 31 are joined by a plurality of supply terminal joints 93E, and the supply terminal 72 and the terminal portion 322 of the input terminal 32 are joined by a plurality of supply terminal joints 93F. As a result, continuous laminate wiring is formed between the terminal portion 312 and the supply terminal 71, and between the terminal portion 322 and the supply terminal 72. Therefore, power supplied from the direct current power source DC to the semiconductor device B2 passes through the laminate wiring. Therefore, the laminate wiring can reduce the inductance generated inside the semiconductor device B2 in a more stable manner. Therefore, the semiconductor device B2 can reduce the internal inductance in a more stable manner.

[0147] In the semiconductor device B2, the bus bar C1 includes an insulator 73 sandwiched in the z direction between two supply terminals 71 and 72. This allows the supply terminals 71 and 72 to be easily laminated together.

[0148] In semiconductor device B2, the supply terminal 71 and the input terminal 31 are joined by three supply terminal joints 93E. Each of these three supply terminal joints 93E is formed by laser welding using the joining method described above. While it is possible to further increase the joint strength between the supply terminal 71 and the input terminal 31 by increasing the number of supply terminal joints 93E, this would increase the number of laser welding operations, which would increase the labor required for the manufacturing process and could cause thermal strain in the supply terminal 71 due to the heat generated by the laser welding. Therefore, to reduce the labor required for the manufacturing process and the effects of thermal strain, it is preferable to join the supply terminal 71 and the input terminal 31 by three supply terminal joints 93E. It is for this reason that the supply terminal 72 and the input terminal 32 are joined by three supply terminal joints 93F.

[0149] In semiconductor device B2, bus bar C1 includes supply terminal 71. Supply terminal 71 includes a base 711 and a plurality of extensions 712 each extending from base 711. As shown in FIG. 23, supply terminal 71 has a portion that is joined to input terminal 31, which is divided into two parts. This further reduces the effects of thermal strain when joined using three supply terminal joints 93E, as described above. This is also the reason why supply terminal 72 has a portion that is joined to input terminal 32, which is divided into two parts, as shown in FIG. 22.

[0150] In the second embodiment, as shown in FIG. 24, a direct-current power supply DC is connected between two supply terminals 71 and 72. However, this is not limiting. For example, as shown in FIG. 25, a capacitor C may be further connected. The capacitor C is connected in parallel to the direct-current power supply DC. The capacitor C may be a ceramic capacitor, a film capacitor, or the like. The capacitance of the capacitor C is set according to the frequency characteristics of the semiconductor device B2. When the multiple switching elements 20 of the semiconductor device B2 are driven, a back electromotive force, which causes inductance, is generated at the two input terminals 31 and 32. The capacitor C functions to store the back electromotive force as an electric charge. Therefore, in the embodiment shown in FIG. 25, the inductance of the semiconductor device B2 can be more effectively reduced. The electric charge stored in the capacitor C is utilized as part of the direct-current power supplied to the semiconductor device B1. Alternatively, as shown in FIG. 26, a series circuit of the capacitor C and a resistor R may be further connected. The series circuit is a so-called RC snubber circuit and is connected in parallel to the direct-current power supply DC. The resistor R can drop the voltage of the back electromotive force generated at the two input terminals 31 and 32. Therefore, in the embodiment shown in Fig. 26, the inductance of the semiconductor device B2 can be reduced as described above, and overcharging of the capacitor C can be prevented.

[0151] Fig. 27 shows a semiconductor device according to a third embodiment. The semiconductor device B3 of the third embodiment is different from the semiconductor device B1 in the shape of the sealing resin 60. Other than that, the semiconductor device B3 is the same as the semiconductor device B1. Fig. 27 is a perspective view showing the semiconductor device B3.

[0152] In this embodiment, the sealing resin 60 has edge portions in the y direction that extend in the x direction in a plan view. The portions of the sealing resin 60 that extend in the x2 direction cover portions of the two input terminals 31 and 32 and the insulating member 39. Furthermore, the portions of the sealing resin 60 that extend in the x1 direction cover portions of the output terminal 33.

[0153] In comparison with the semiconductor device B1, the semiconductor device B3 has a larger sealing resin 60, which further covers the two input terminals 31 and 32, the output terminal 33, and a portion of the insulating member 39. As a result, the semiconductor device B3 can better protect the two input terminals 31 and 32, the output terminal 33, and the insulating member 39 from deterioration, bending, and the like than the semiconductor device B1.

[0154] The bus bar C1 shown in the second embodiment may also be connected to the semiconductor device B3.

[0155] In the above-described joined structure A1, the surfaces of the first metal member 91 and the second metal member 92 are described as being Cu, but this is not limiting. For example, the surfaces of either or both of the first metal member 91 and the second metal member 92 may be covered with a metal plating. Examples of such metal plating include Sn and Ni (nickel). Below, a case where either the first metal member 91 or the second metal member 92 is covered with a metal plating will be described. Note that the melting point of Cu is 1085°C, the melting point of Sn is 232°C, and the melting point of Ni is 1453°C.

[0156] 28 to 32 are diagrams for explaining a joint structure (welded portion 93) in a modified example. Each of the welded portions 93 shown in these figures is formed by performing only the first scan (without performing the second scan). Each of the welded portions 93 shown in these figures is a cross-sectional schematic diagram showing each of the joint structures.

[0157] FIG. 28 shows an example where neither the surface of the first metal member 91 nor the surface of the second metal member 92 is plated. FIG. 28 corresponds to the joined structure A1 and is shown for comparison with examples of modified examples (FIGS. 29 to 32). FIG. 29 shows an example where the first metal member 91 is not covered with metal plating and the second metal member 92 is covered with Sn plating. FIG. 30 shows an example where the first metal member 91 is not covered with metal plating and the second metal member 92 is covered with Ni plating. FIG. 31 shows an example where the first metal member 91 is covered with Sn plating and the second metal member 92 is not covered with metal plating. FIG. 32 shows an example where the first metal member 91 is covered with Ni plating and the second metal member 92 is not covered with metal plating.

[0158] 29 and 31, when the first metal member 91 or the second metal member 92 is covered with Sn plating, it can be seen that the welded portion 93 bulges outward near the interface between the first metal member 91 and the second metal member 92. This is because the melting point of Sn is lower than that of Cu, and therefore Sn melts before Cu due to heat generated by the laser beam. In addition, the composition of the welded portion 93 contains a CuSn alloy.

[0159] On the other hand, as shown in Figures 30 and 32, when the first metal member 91 or the second metal member 92 is covered with Ni plating, there is no bulge in the welded portion 93 near the interface between the first metal member 91 and the second metal member 92, as shown in Figures 29 and 31. Furthermore, the composition of the welded portion 93 does not contain a CuNi alloy, and Cu and Ni coexist.

[0160] Even when either or both of the first metal member 91 and the second metal member 92 are metal plated (see FIGS. 29 to 32), the bonding strength between the first metal member 91 and the second metal member 92 is substantially the same as when they are not metal plated (see FIG. 28). The conductivity at each welded portion 93 is also substantially the same. That is, in the bonded structure of the present disclosure, the first metal member 91 and the second metal member 92 may be metal plated as appropriate.

[0161] The bonded structure, semiconductor device, and bonding method according to the present disclosure are not limited to the above-described embodiments. The specific configurations of each part of the bonded structure and semiconductor device according to the present disclosure, and the specific processing of each step of the bonding method according to the present disclosure can be freely designed in various ways.

Claims

1. a plurality of switching elements, each having a first electrode and a second electrode formed on a main surface of the element facing one side in a first direction and a back surface electrode formed on a back surface of the element facing the other side in the first direction, and each performing a switching operation between the first electrode and the back surface electrode in response to a signal input to the second electrode; a sealing resin that seals each of the plurality of switching elements; a first input terminal including a first pad portion covered with the sealing resin and a first terminal portion exposed from the sealing resin; a second input terminal including a second pad portion covered with the sealing resin and a second terminal portion exposed from the sealing resin; an output terminal including a third pad portion covered with the sealing resin and a third terminal portion exposed from the sealing resin; a first supply terminal conductively joined to the first terminal portion; Equipped with the first input terminal, the second input terminal, and the output terminal are electrically connected to the plurality of switching elements; the sealing resin surrounds at least a portion of the first terminal portion, at least a portion of the second terminal portion, and at least a portion of the third terminal portion when viewed in the first direction; the conductive joint between the first supply terminal and the first terminal portion comprises a first welded portion where a part of the first supply terminal and a part of the first terminal portion are fusion-welded.

2. 2 . The semiconductor device according to claim 1 , wherein the first welded portion penetrates the first supply terminal in the first direction and is fusion-welded to a depth partway down to the first terminal portion.

3. 3. The semiconductor device according to claim 1, wherein the first supply terminal and the first terminal portion are electrically connected by laser welding, and the surface of the first welded portion is not flat but has a portion that is raised higher than the surface of the first terminal portion.

4. the first welded portion has an annular outer circumferential edge when viewed in the first direction and a circular crater portion when viewed in the first direction, 4. The semiconductor device according to claim 1, wherein the diameter of the crater portion in the first welded portion is smaller than the radius of the outer periphery.

5. a second supply terminal electrically connected to the second terminal portion; 5. The semiconductor device according to claim 1, wherein the conductive joint between the second supply terminal and the second terminal portion comprises a second welded portion formed by fusion welding a portion of the second supply terminal and a portion of the second terminal portion.

6. 6. The semiconductor device according to claim 5, wherein the second welded portion penetrates the second supply terminal in the first direction and is fusion-welded to a depth partway down to the second terminal portion.

7. 7. The semiconductor device according to claim 5, wherein the conductive joining between the second supply terminal and the second terminal portion is laser welding, and the surface of the second welded portion is not flat but has a portion that is raised higher than a surface of the second terminal portion.

8. the second welded portion has an annular outer peripheral edge when viewed in the first direction and a circular crater portion when viewed in the first direction, 8. The semiconductor device according to claim 5, wherein the diameter of the crater portion in the second welded portion is smaller than the radius of the outer periphery.

9. 9. The semiconductor device according to claim 5, wherein the first supply terminal and the second supply terminal overlap each other when viewed in the first direction.

10. 10. The semiconductor device according to claim 5, wherein each of the first supply terminal and the second supply terminal includes a metal.

11. an insulator located between the first supply terminal and the second supply terminal; a resin portion covering a part of the insulator; Furthermore, 11. The semiconductor device according to claim 5, wherein the first supply terminal, the second supply terminal, the insulator, and the resin portion form a bus bar.

12. The semiconductor device according to claim 11 , wherein the resin portion includes an epoxy resin.

13. 13. The semiconductor device according to claim 5, wherein the first supply terminal and the second supply terminal are connected to an external power supply.

14. the plurality of switching elements include at least one first switching element and at least one second switching element; 14. The semiconductor device according to claim 1, wherein the at least one first switching element and the at least one second switching element are electrically connected in series to form a half-bridge switching circuit.

15. each of the at least one first switching element and the at least one second switching element is a MOSFET; 15. The semiconductor device according to claim 14, wherein in each of the at least one first switching element and the at least one second switching element, the first electrode is a source electrode, the second electrode is a gate electrode, and the back surface electrode is a drain electrode.

16. 16. The semiconductor device according to claim 14, wherein each of the at least one first switching element and the at least one second switching element is made of a semiconductor material mainly containing silicon carbide.

17. 17. The semiconductor device according to claim 14, wherein the first electrode of the at least one first switching element and the back surface electrode of the at least one second switching element are electrically connected to each other and are also electrically connected to the output terminal.

18. the back electrode of the at least one first switching element is electrically connected to the first input terminal; The semiconductor device according to claim 17 , wherein the first electrode of the at least one second switching element is electrically connected to the second input terminal.

Images