Electronic device

Abstract

An electronic device according to the present invention comprises: an electroconductive part having a main surface facing one side in the thickness direction; an electronic element positioned on the one side in the thickness direction with respect to the main surface; and a stress buffer layer positioned between the main surface and the electronic element in the thickness direction. The stress buffer layer has a first surface facing the one side in the thickness direction and a second surface facing the other side in the thickness direction. The electronic element has an element first surface facing the one side in the thickness direction and an element second surface facing the other side in the thickness direction. The surface area of the second surface is larger than the surface area of the element second surface. When viewed in the thickness direction, the second surface overlaps the entirety of the element second surface.

Description

electronic equipment

[0001] This disclosure relates to an electronic device.

[0002] Conventionally, semiconductor devices equipped with semiconductor elements having a switching function (MOSFETs, IGBTs, etc.) have been known as one of various electronic devices, and are mainly used for power conversion. Patent Document 1 discloses an example of such a semiconductor device. The semiconductor device disclosed in the document comprises a first wiring and a second wiring located apart from each other, a first switching element conductively joined to the first wiring, and a second switching element that conducts to the first switching element and the second wiring. Furthermore, the semiconductor device comprises a first passive element conductively joined to the first wiring, a second passive element conductively joined to the second wiring, and a conductive material connecting the first passive element and the second passive element. At least one of the first passive element and the second passive element is a capacitive element (capacitor). Thus, a snubber circuit is configured in the semiconductor device.

[0003] The first and second switching elements are constructed using semiconductor materials, for example, mainly silicon carbide (SiC). The capacitive element is, for example, a ceramic capacitor. The coefficients of thermal expansion of these constituent materials are smaller than those of copper (Cu), which constitutes the first and second wiring. The heat generated from the first and second switching elements increases the thermal stress between each of the first and second switching elements and the first or second wiring to which each element is conductively bonded. Since there is a concern that the elements may be damaged by this thermal stress, it is desirable to reduce the thermal stress acting on the elements.

[0004] International Publication No. 2020 / 218298

[0005] [Summary] One objective of this disclosure is to provide a semiconductor device that is an improvement over conventional devices. In particular, in view of the above circumstances, one objective of this disclosure is to provide an electronic device that can reduce the thermal stress acting on electronic elements.

[0006] An electronic device provided by a first aspect of this disclosure comprises: a conductive portion having a main surface facing one side in the thickness direction; one or more electronic elements located on one side in the thickness direction with respect to the main surface; and a stress buffer layer located in the thickness direction between the main surface and at least one of the one or more electronic elements. The stress buffer layer has a first surface facing one side in the thickness direction and a second surface facing the other side in the thickness direction. The electronic element has a first surface facing one side in the thickness direction and a second surface facing the other side in the thickness direction. The area of ​​the second surface is larger than the area of ​​the second surface. Viewed in the thickness direction, the second surface overlaps with the entirety of the second surface.

[0007] Other features and advantages of this disclosure will become more apparent from the detailed description below, with reference to the accompanying drawings.

[0008] Figure 1 is a plan view showing an electronic device according to the first embodiment of the present disclosure. Figure 2 is a plan view showing an electronic device according to the first embodiment of the present disclosure. Figure 3 is a bottom view showing an electronic device according to the first embodiment of the present disclosure. Figure 4 is a left side view showing an electronic device according to the first embodiment of the present disclosure. Figure 5 is a cross-sectional view along the line V-V in Figure 1. Figure 6 is a cross-sectional view along the line VI-VI in Figure 1. Figure 7 is a cross-sectional view along the line VII-VII in Figure 1. Figure 8 is a cross-sectional view along the line VIII-VIII in Figure 1. Figure 9 is a partially enlarged view of Figure 5. Figure 10 is a partially enlarged view of Figure 5. Figure 11 is a partially enlarged view of Figure 6. Figure 12 is a partially enlarged view of Figure 11. Figure 13 is a cross-sectional view along the line XIII-XIII in Figure 12. Figure 14 is a partially enlarged cross-sectional view similar to Figure 12, showing an electronic device according to a first modification of the first embodiment. Figure 15 is a cross-sectional view along the line XV-XV in Figure 14. Figure 16 is a partially enlarged cross-sectional view similar to Figure 12, showing an electronic device according to a second modification of the first embodiment. Figure 17 is a cross-sectional view along the line XVII-XVII in Figure 16. Figure 18 is a partially enlarged cross-sectional view similar to Figure 12, showing an electronic device according to a third modification of the first embodiment. Figure 19 is a cross-sectional view along the line XIX-XIX in Figure 18. Figure 20 is a partially enlarged cross-sectional view similar to Figure 12, showing an electronic device according to a fourth modification of the first embodiment. Figure 21 is a cross-sectional view along the line XXI-XXI in Figure 20. Figure 22 is a partially enlarged cross-sectional view similar to Figure 12, showing an electronic device according to a fifth modification of the first embodiment. Figure 23 is a cross-sectional view along XIII-XXIII in Figure 22. Figure 24 is a partially enlarged cross-sectional view similar to Figure 12, showing an electronic device according to a sixth modification of the first embodiment. Figure 25 is a partially enlarged cross-sectional view similar to Figure 12, showing an electronic device according to a seventh modification of the first embodiment. Figure 26 is a plan view showing an electronic device according to a second embodiment of the present disclosure. Figure 27 is a plan view showing an electronic device according to a second embodiment of the present disclosure. Figure 28 is a cross-sectional view along the line XXVIII-XXVIII in Figure 26. Figure 29 is a cross-sectional view along the line XXIX-XXIX in Figure 26. Figure 30 is a partially enlarged view of Figure 29. Figure 31 is a partially enlarged view of Figure 30. Figure 32 is a cross-sectional view along the line XXXII-XXXII in Figure 31.Figure 33 is a perspective view showing an electronic device according to a third embodiment of the present disclosure. Figure 34 is a plan view showing an electronic device according to a third embodiment of the present disclosure. Figure 35 is a plan view showing an electronic device according to a third embodiment of the present disclosure. Figure 36 is a cross-sectional view along the line XXXVI-XXXVI in Figure 35. Figure 37 is a cross-sectional view along the line XXXVII-XXXVII in Figure 35. Figure 38 is a cross-sectional view along the line XXXVIII-XXXVIII in Figure 35. Figure 39 is a partially enlarged view of Figure 38. Figure 40 is a cross-sectional view along the line XL-XL in Figure 39.

[0009] [Detailed Description] Preferred embodiments of this disclosure will be described below with reference to the drawings.

[0010] The terms "first," "second," "third," etc., used in this disclosure are merely labels and are not necessarily intended to assign a sequence to the objects.

[0011] In this disclosure, "object A is formed on object B" and "object A is formed on object B" include, unless otherwise specified, "object A is directly formed on object B" and "object A is formed on object B with another object interposed between object A and object B." Similarly, "object A is located on object B" and "object A is located on object B" include, unless otherwise specified, "object A is directly located on object B" and "object A is located on object B with another object interposed between object A and object B." Similarly, "object A is located on object B" includes, unless otherwise specified, "object A is located on object B in contact with object B" and "object A is located on object B with another object interposed between object A and object B." Furthermore, unless otherwise specified, "object A overlaps with object B when viewed in a certain direction" includes "object A overlapping with all of object B" and "object A overlapping with a part of object B." Also, in this disclosure, "a surface A facing direction B (one or the other side of it)" is not limited to the case where the angle of surface A with respect to direction B is 90°, but also includes the case where surface A is inclined with respect to direction B.

[0012] First Embodiment: Figures 1 to 13 show an electronic device according to the first embodiment of the present disclosure. The electronic device A10 of this embodiment includes a pair of support members 10, a first conductive member 11, a second conductive member 12, a third conductive member 13, a plurality of fourth conductive members 14, a plurality of electronic elements 21, a plurality of electronic elements 22, an electronic element 23, a stress buffer layer 31, a first bonding layer 35, a second bonding layer 36, and a sealing resin 50. The first conductive member 11 includes a conductive portion 111, a first terminal 112, and a first cushioning material 113. The second conductive member 12 includes a main material 121 and a second terminal 122. The third conductive member 13 includes a conductive portion 131, a third terminal 132, and a second cushioning material 133. Furthermore, the electronic device A10 includes a first wiring 15, a second wiring 16, a first gate terminal 171, a second gate terminal 172, a first detection terminal 181, a second detection terminal 182, a plurality of first wires 41, a plurality of second wires 42, a plurality of third wires 43, a plurality of fourth wires 44, a plurality of fifth wires 45, and a plurality of sixth wires 46.

[0013] Figure 1 is a plan view of the electronic device A10, showing the view through the sealing resin 50. Figure 2 is a plan view of the electronic device A10, showing the view through the sealing resin 50 and the second conductive member 12. Figure 3 is a bottom view of the electronic device A10. Figure 4 is a left side view of the electronic device A10. Figure 5 is a cross-sectional view along the line V-V in Figure 1. Figure 6 is a cross-sectional view along the line VI-VI in Figure 1. Figure 7 is a cross-sectional view along the line VII-VII in Figure 1. Figure 8 is a cross-sectional view along the line VIII-VIII in Figure 1. Figure 9 is a partially enlarged view of Figure 5, showing the electronic element 21 and its vicinity. Figure 10 is a partially enlarged view of Figure 5, showing the electronic element 22 and its vicinity. Figure 11 is a partially enlarged view of Figure 6. Figure 12 is a partially enlarged view of Figure 11. Figure 13 is a cross-sectional view along the line XIII-XIII in Figure 12. In Figure 1, the outline of the permeated sealing resin 50 is shown by dashed lines. In Figure 2, the outlines of the permeated sealing resin 50 and the second conductive member 12 are shown by dashed lines. In Figures 12 and 13, the sealing resin 50 and the sixth wire 46 are omitted.

[0014] In describing the electronic device A10, for convenience, the normal direction of the main surface 111A of the conductive part 111, which will be described later, is an example of the "thickness direction" in this disclosure and is referred to as the "thickness direction z". The direction perpendicular to the thickness direction z is an example of the "first direction" in this disclosure and is referred to as the "first direction x". The direction perpendicular to both the thickness direction z and the first direction x is an example of the "second direction" in this disclosure and is referred to as the "second direction y". Furthermore, one side of the thickness direction z corresponds to the "one side of the thickness direction" in this disclosure and is referred to as the "z1 side of the thickness direction z", and the other side of the thickness direction z corresponds to the "other side of the thickness direction" in this disclosure and is referred to as the "z2 side of the thickness direction z".

[0015] Electronic device A10 converts the DC power supply voltage applied to the first terminal 112 and the second terminal 122 into AC power using multiple electronic elements 21 and 22. The converted AC power is input to a power supply target such as a motor through the third terminal 132. Electronic device A10 constitutes part of a power conversion circuit such as an inverter.

[0016] As shown in Figures 5 and 6, the pair of support members 10 are located on the opposite side (z2 side of the thickness direction z) from the plurality of electronic elements 21 and 22, with respect to the conductive parts 111 and 131 in the thickness direction z. The pair of support members 10 support the conductive parts 111 and 131, respectively. The pair of support members 10 are made of, for example, a DBC (Direct Bonded Copper) substrate. As shown in Figures 5 and 6, each of the pair of support members 10 includes an insulating layer 101, a support layer 102, and a heat dissipation layer 103. The pair of support members 10 are covered with sealing resin 50, except for a portion of the heat dissipation layer 103.

[0017] As shown in Figures 5 and 6, the insulating layer 101 includes a portion located between the support layer 102 and the heat dissipation layer 103 in the thickness direction z. The insulating layer 101 is made of a material with higher thermal conductivity. For example, the insulating layer 101 is made of ceramics containing aluminum nitride (AlN). The thickness of the insulating layer 101 is thinner than the thickness of the conductive portion 111 and the conductive portion 131, respectively.

[0018] As shown in Figures 5 and 6, the support layer 102 is located between the insulating layer 101 and the conductive portions 111 and 131 in the thickness direction z. The composition of the support layer 102 includes copper (Cu). Viewed in the thickness direction z, the support layer 102 is surrounded by the periphery of the insulating layer 101.

[0019] As shown in Figures 5 and 6, the heat dissipation layer 103 is located on the opposite side of the support layer 102 (on the z2 side of the thickness direction z) from the insulating layer 101 in the thickness direction z. As shown in Figure 3, a portion of the heat dissipation layer 103 is exposed from the sealing resin 50. When the electronic device A10 is used, a heat sink (not shown) is bonded to the heat dissipation layer 103. The composition of the heat dissipation layer 103 includes copper. Viewed in the thickness direction z, the heat dissipation layer 103 is surrounded by the periphery of the insulating layer 101.

[0020] The conductive portions 111 and 131 are individually bonded to the support layer 102 of the pair of support members 10, as shown in Figures 5 and 6. The conductive portions 111 and 131 are bonded to the support layer 102, for example, via solder. The composition of the conductive portions 111 and 131 includes copper. The conductive portion 131 is located away from the conductive portion 111 in a first direction x. As shown in Figures 5 and 6, the conductive portion 111 has a main surface 111A facing one side (z1 side) in the thickness direction z. In the thickness direction z, the pair of support members 10 are located on the opposite side of the main surface 111A. The main surface 111A faces a plurality of electronic elements 21. As shown in Figures 5 and 6, the conductive portion 131 has a main surface 131A facing the same side (z1 side of the thickness direction z) as the main surface 111A in the thickness direction z. The main surface 131A faces multiple electronic elements 22.

[0021] As shown in Figures 5 to 7, the multiple electronic elements 21 are joined to the main surface 111A of the conductive portion 111. All of the multiple electronic elements 21 are identical. In the electronic device A10, the multiple electronic elements 21 are switching elements, such as MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors). In addition, the multiple electronic elements 21 may be field-effect transistors including MISFETs (Metal-Insulator-Semiconductor Field-Effect Transistors) or bipolar transistors such as IGBTs (Insulated Gate Bipolar Transistors). In the description of the electronic device A10, the multiple electronic elements 21 are assumed to be n-channel type and vertically structured MOSFETs. The multiple electronic elements 21 include a compound semiconductor substrate. The composition of the compound semiconductor substrate includes silicon carbide (SiC). Each of the multiple electronic elements 21 is rectangular when viewed in the thickness direction z. Multiple electronic elements 21 are arranged along the second direction y.

[0022] As shown in Figure 9, each of the multiple electronic elements 21 has a first element surface 21A and a second element surface 21B. In each electronic element 21, the first element surface 21A and the second element surface 21B are separated in the thickness direction z. The first element surface 21A faces the z1 side in the thickness direction z, and the second element surface 21B faces the z2 side in the thickness direction z.

[0023] As shown in Figure 9, each of the multiple electronic elements 21 has a back electrode 211, a main electrode 212, and a gate electrode 213. The back electrode 211 is located on the second surface 21B of the element. The back electrode 211 is located on the side facing the main surface 111A of the conductive portion 111. A current corresponding to the power before it is converted by the electronic element 21 flows through the back electrode 211. In other words, the back electrode 211 corresponds to the drain electrode of the electronic element 21.

[0024] As shown in Figure 9, the main surface electrode 212 is positioned on the first surface 21A of the element (opposite the back surface electrode 211 in the thickness direction z). A current corresponding to the power converted by the electronic element 21 flows through the main surface electrode 212. In other words, the main surface electrode 212 corresponds to the source electrode of the electronic element 21.

[0025] As shown in Figure 9, the gate electrode 213 is positioned on the first surface 21A of the element (on the same side as the main surface electrode 212 in the thickness direction z). A gate voltage is applied to the gate electrode 213 to drive the electronic element 21. As shown in Figure 2, the area of ​​the gate electrode 213 is smaller than the area of ​​the main surface electrode 212 when viewed in the thickness direction z.

[0026] As shown in Figure 9, a stress buffer layer 31 is located between the main surface 111A (conductive portion 111) and the back electrode 211 (electronic element 21) in the thickness direction z. The stress buffer layer 31 is conductive. The stress buffer layer 31 is conductively bonded to the main surface 111A of the conductive portion 111 via the first bonding layer 35. The stress buffer layer 31 is also conductively bonded to the back electrode 211 of the electronic element 21 via the second bonding layer 36. As a result, the back electrodes 211 of the multiple electronic elements 21 are electrically connected to the first conductive member 11. The composition of the stress buffer layer 31 includes, for example, iron (Fe) and nickel (Ni). The first bonding layer 35 and the second bonding layer 36 are, for example, solder. Alternatively, the first bonding layer 35 and the second bonding layer 36 may be sintered metal containing silver or the like, or a metallic bonding layer in which two metal layers in contact with each other are bonded by solid-phase diffusion. The thickness of the stress buffer layer 31 is thinner than the thickness of the conductive portion 111. The thickness of the first bonding layer 35 and the second bonding layer 36 are each thinner than the thickness of the stress buffer layer 31.

[0027] The stress buffer layer 31 has a first surface 311 and a second surface 312. The first surface 311 and the second surface 312 are separated in the thickness direction z. The first surface 311 faces the z1 side in the thickness direction z, and the second surface 312 faces the z2 side in the thickness direction z. In the electronic device A10, the area of ​​the second surface 312 is larger than the area of ​​the second surface 21B of the electronic element 21. In the thickness direction z, the second surface 312 overlaps with the entire second surface 21B of the element. Also, the area of ​​the second surface 312 is larger than the area of ​​the first surface 311. In the thickness direction z, the second surface 312 overlaps with the entire first surface 311. The area of ​​the first surface 311 is larger than the area of ​​the second surface 21B of the element. Viewed in the thickness direction z, the first surface 311 overlaps with the entirety of the second surface 21B of the element.

[0028] In electronic device A10, the coefficient of thermal expansion of the stress buffer layer 31 is smaller than that of the conductive part 111. Furthermore, the coefficient of thermal expansion of the stress buffer layer 31 is smaller than that of the electronic element 21. The coefficient of thermal expansion of the conductive part 111 (copper) is 17.7 × 10⁻⁶. -6 The temperature is / °C. The coefficient of linear expansion of the electronic element 21 (silicon carbide) is 4.0 × 10⁻⁶. -6 The temperature is / °C. The coefficient of linear expansion of the stress buffer layer 31 is 3.0 × 10⁻⁶. -6 It is preferable that the temperature is below / °C. Examples of such stress buffering layers 31 include Invar, which is an alloy of iron and nickel.

[0029] As shown in Figures 5, 6, and 8, the multiple electronic elements 22 are bonded to the main surface 131A of the conductive portion 131. The multiple electronic elements 22 are the same elements (switching elements) as the multiple electronic elements 21. Therefore, the multiple electronic elements 22 are n-channel type and vertical structure MOSFETs. The multiple electronic elements 22 include a compound semiconductor substrate, and the composition of the compound semiconductor substrate includes silicon carbide (SiC). Each of the multiple electronic elements 22 is rectangular when viewed in the thickness direction z. The multiple electronic elements 22 are arranged along the second direction y.

[0030] As shown in Figure 10, each of the multiple electronic elements 22 has a first element surface 22A and a second element surface 22B. In each electronic element 22, the first element surface 22A and the second element surface 22B are separated in the thickness direction z. The first element surface 22A faces the z1 side in the thickness direction z, and the second element surface 22B faces the z2 side in the thickness direction z.

[0031] As shown in Figure 10, each of the multiple electronic elements 22 has a back electrode 221, a main electrode 222, and a gate electrode 223. The back electrode 221 is located on the second surface 22B of the element. The back electrode 221 is located on the side of the conductive portion 131 facing the main surface 131A. A current corresponding to the power before it is converted by the electronic element 22 flows through the back electrode 221. In other words, the back electrode 221 corresponds to the drain electrode of the electronic element 22.

[0032] As shown in Figure 10, the main surface electrode 222 is positioned on the first surface 22A of the element (opposite the back surface electrode 221 in the thickness direction z). A current corresponding to the power converted by the electronic element 22 flows through the main surface electrode 222. In other words, the main surface electrode 222 corresponds to the source electrode of the electronic element 22.

[0033] As shown in Figure 10, the gate electrode 223 is positioned on the first surface 22A of the element (on the same side as the main surface electrode 222 in the thickness direction z). A gate voltage for driving the electronic element 22 is applied to the gate electrode 223. As shown in Figure 2, the area of ​​the gate electrode 223 is smaller than the area of ​​the main surface electrode 222 when viewed in the thickness direction z.

[0034] As shown in Figure 10, a stress buffer layer 31 is located between the main surface 131A (conductive portion 131) and the back electrode 221 (electronic element 22) in the thickness direction z. The stress buffer layer 31 is conductive. The stress buffer layer 31 is conductively bonded to the main surface 131A of the conductive portion 131 via a first bonding layer 35. The stress buffer layer 31 is also conductively bonded to the back electrode 221 of the electronic element 22 via a second bonding layer 36. As a result, the back electrodes 221 of the multiple electronic elements 22 are electrically connected to the third conductive member 13. The composition of the stress buffer layer 31 includes, for example, iron and nickel. The first bonding layer 35 and the second bonding layer 36 are, for example, solder. Alternatively, the first bonding layer 35 and the second bonding layer 36 may be sintered metal containing silver or the like, or a metallic bonding layer in which two metal layers in contact with each other are bonded by solid-phase diffusion. The thickness of the stress buffer layer 31 is thinner than the thickness of the conductive portion 131. The thickness of the first bonding layer 35 and the second bonding layer 36 is thinner than the thickness of the stress buffer layer 31.

[0035] The stress buffer layer 31 located between the conductive part 131 and the electronic element 22 has the same configuration as the stress buffer layer 31 located between the conductive part 111 and the electronic element 21 described above. The stress buffer layer 31 located between the conductive part 131 and the electronic element 22 has a first surface 311 and a second surface 312. The first surface 311 and the second surface 312 are separated in the thickness direction z. The first surface 311 faces the z1 side in the thickness direction z, and the second surface 312 faces the z2 side in the thickness direction z. In the electronic device A10, the area of ​​the second surface 312 is larger than the area of ​​the second surface 22B of the electronic element 22. Viewed in the thickness direction z, the second surface 312 overlaps with the entire second surface 22B of the element. Also, the area of ​​the second surface 312 is larger than the area of ​​the first surface 311. Viewed in the thickness direction z, the second surface 312 overlaps with the entire first surface 311. The area of ​​the first surface 311 is larger than the area of ​​the second surface 22B of the element. Viewed in the thickness direction z, the first surface 311 overlaps with the entire second surface 22B of the element.

[0036] In the electronic device A10, the coefficient of thermal expansion of the stress buffer layer 31 located between the conductive part 131 and the electronic element 22 is smaller than the coefficient of thermal expansion of the conductive part 131. Furthermore, the coefficient of thermal expansion of the stress buffer layer 31 is smaller than the coefficient of thermal expansion of the electronic element 22. The coefficient of thermal expansion of the conductive part 131 (copper) is 17.7 × 10⁻⁶.-6 / °C. The linear expansion coefficient of the electronic element 22 (silicon carbide) is 4.0×10 -6 / °C. The linear expansion coefficient of the stress buffer layer 31 is preferably 3.0×10 -6 / °C or less. Examples of such a stress buffer layer 31 include an Invar material, which is an alloy of iron and nickel.

[0037] As shown in FIG. 2, the first wiring 15 is located adjacent to a plurality of electronic elements 21 in the first direction x. The first wiring 15 is joined to the main surface 111A of the conductive portion 111. In the electronic device A10, the first wiring 15 is composed of, for example, a DBC substrate, similar to the pair of support members 10. As shown in FIGS. 5 and 6, the first wiring 15 includes a first insulating layer 151, a first gate wiring 152, a first detection wiring 153, and a first support layer 154.

[0038] As shown in FIG. 2, the first insulating layer 151 extends in the second direction y. As shown in FIGS. 5 and 6, the first insulating layer 151 is located on the main surface 111A of the conductive portion 111. The first insulating layer 151 is made of, for example, ceramics containing aluminum nitride.

[0039] As shown in FIGS. 2, 5, and 6, the first gate wiring 152 is disposed on the first insulating layer 151. In the thickness direction z, the first gate wiring 152 is located on the side opposite to the conductive portion 111 (the z1 side in the thickness direction z) with respect to the first insulating layer 151. The first gate wiring 152 extends in the second direction y. The first gate wiring 152 is electrically connected to the gate electrodes 213 of the plurality of electronic elements 21. The composition of the first gate wiring 152 contains, for example, copper. <000009As shown in FIGS. 2, 5, and 6, the first detection wiring 153 is disposed on the first insulating layer 151. The first detection wiring 153 is located on the opposite side of the plurality of electronic elements 21 with respect to the first gate wiring 152 in the first direction x. Further, the first detection wiring 153 is located on the same side (z1 side in the thickness direction z) as the first gate wiring 152 with respect to the first insulating layer 151 in the thickness direction z. The first detection wiring 153 extends in the second direction y. The first detection wiring is electrically connected to the main surface electrodes 212 of the plurality of electronic elements 21. The composition of the first detection wiring 153 includes, for example, copper.

[0041] As shown in FIGS. 5, 6, and 9, the first support layer 154 is located on the opposite side (z2 side in the thickness direction z) of the first gate wiring 152 and the first detection wiring 153 with respect to the first insulating layer 151 in the thickness direction z. The first support layer 154 is joined to the main surface 111A of the conductive portion 111 via, for example, solder. The composition of the first support layer 154 includes, for example, copper.

[0042] As shown in FIG. 2, each of the plurality of first wires forty-one is electrically connected to one of the gate electrodes of the plurality of electronic elements 21 and the first gate wiring 152 of the first wiring 15. Thereby, the gate electrodes of the plurality of electronic elements 21 are electrically connected to the first gate wiring 152. The composition of the plurality of first wires forty-one includes, for example, gold (Au). In addition, the composition of the plurality of first wires forty-one may include copper or aluminum (Al).

[0043] As shown in FIG. 2, each of the plurality of second wires 42 is electrically connected to one of the main surface electrodes 212 of the plurality of electronic elements 21 and the first detection wiring 153 of the first wiring 15. Thereby, the main surface electrodes 212 of the plurality of electronic elements 21 are electrically connected to the first detection wiring 153. The composition of the plurality of second wires includes, for example, gold. In addition, the composition of the plurality of second wires 42 may include copper or aluminum.

[0044] As shown in Figures 1 and 2, the first gate terminal 171 is located next to the conductive portion 111 in the second direction y. The first gate terminal 171 is electrically connected to the first gate wiring 152 of the first wiring 15. The first gate terminal 171 is a metal lead made of a material including, for example, copper or a copper alloy. As shown in Figure 3, a portion of the first gate terminal 171 is covered by the sealing resin 50. Viewed in the first direction x, the first gate terminal 171 is L-shaped. As shown in Figures 4 and 7, the first gate terminal 171 includes a portion that stands upright in the thickness direction z (on the z1 side of the thickness direction z). This portion is exposed from the sealing resin 50. A gate voltage is applied to the first gate terminal 171 to drive a plurality of electronic elements 21.

[0045] As shown in Figures 1 and 2, the first detection terminal 181 is located next to the first gate terminal 171 in the first direction x. The first detection terminal 181 is electrically connected to the first detection wiring 153 of the first wiring 15. The first detection terminal 181 is a metal lead made of a material including, for example, copper or a copper alloy. As shown in Figure 3, a portion of the first detection terminal 181 is covered by the sealing resin 50. Viewed in the first direction x, the first detection terminal 181 is L-shaped. As shown in Figure 4, the first detection terminal 181 includes a portion that stands upright in the thickness direction z (on the z1 side of the thickness direction z). This portion is exposed from the sealing resin 50. A voltage equivalent to the voltage applied to the main surface electrodes 212 of the plurality of electronic elements 21 is applied to the first detection terminal 181.

[0046] As shown in Figure 2, the second wiring 16 is located next to a plurality of electronic elements 22 in the first direction x. The second wiring 16 is bonded to the main surface 131A of the conductive portion 131. In the electronic device A10, the second wiring 16, like the first wiring 15, is made of, for example, a DBC substrate. As shown in Figures 5 and 6, the second wiring 16 has a second insulating layer 161, a second gate wiring 162, a second detection wiring 163, and a second support layer 164.

[0047] As shown in Figure 2, the second insulating layer 161 extends in the second direction y. As shown in Figures 5 and 6, the second insulating layer 161 is located on the main surface 131A of the conductive portion 131. The second insulating layer 161 is made of, for example, ceramics containing aluminum nitride.

[0048] As shown in Figures 2, 5, and 6, the second gate wiring 162 is located on the second insulating layer 161. The second gate wiring 162 is located on the opposite side of the conductive portion 131 (on the z1 side of the thickness direction z) with respect to the first insulating layer 151 in the thickness direction z. The second gate wiring 162 extends in the second direction y. The second gate wiring 162 is electrically connected to the gate electrodes 223 of the multiple electronic elements 22. The composition of the second gate wiring 162 includes, for example, copper.

[0049] As shown in Figures 2, 5, and 6, the second detection wiring 163 is positioned on the second insulating layer 161. The second detection wiring 163 is located on the opposite side of the multiple electronic elements 22 from the second gate wiring 162 in the first direction x, with reference to the second gate wiring 162. Furthermore, the second detection wiring 163 is located on the same side (z1 side of the thickness direction z) as the second gate wiring 162 with reference to the second insulating layer 161 in the thickness direction z. The second detection wiring 163 extends in the second direction y. The second detection wiring 163 is electrically connected to the main surface electrodes 222 of the multiple electronic elements 22. The composition of the second detection wiring 163 includes, for example, copper.

[0050] As shown in Figures 5, 6, and 10, the second support layer 164 is located on the opposite side (z2 side of the thickness direction z) from the second gate wiring 162 and the second detection wiring 163 with respect to the second insulating layer 161 in the thickness direction z. The second support layer 164 is joined to the main surface 131A of the conductive part 131, for example, via solder. The composition of the second support layer 164 includes, for example, copper.

[0051] Each of the multiple third wires 43 is electrically connected to the gate electrode 223 of one of the multiple electronic elements 22 and to the second gate wiring 162 of the second wiring 16, as shown in Figure 2. As a result, the gate electrode 223 of the electronic element 22 is electrically connected to the second gate wiring 162. The composition of the multiple third wires 43 includes, for example, gold. In addition, the composition of the multiple third wires 43 may include copper or aluminum.

[0052] Each of the multiple fourth wires 44 is electrically connected to the main surface electrode 222 of one of the multiple electronic elements 22 and to the second detection wiring 163 of the second wiring 16, as shown in Figure 2. As a result, the main surface electrodes 222 of the multiple electronic elements 22 are electrically connected to the second detection wiring 163. The composition of the multiple fourth wires 44 includes, for example, gold. In addition, the composition of the multiple fourth wires 44 may include copper or aluminum.

[0053] As shown in Figures 1 and 2, the second gate terminal 172 is located next to the conductive portion 131 in the second direction y. The second gate terminal 172 is located on the same side as the first gate terminal 171 with respect to the pair of support members 10 in the second direction y. The second gate terminal 172 is electrically connected to the second gate wiring 162 of the second wiring 16. The second gate terminal 172 is a metal lead made of a material including, for example, copper or a copper alloy. As shown in Figure 3, a portion of the second gate terminal 172 is covered by the sealing resin 50. Viewed in the first direction x, the second gate terminal 172 is L-shaped. As shown in Figures 4 and 8, the second gate terminal 172 includes a portion that stands upright in the thickness direction z (on the z1 side of the thickness direction z). This portion is exposed from the sealing resin 50. A gate voltage is applied to the second gate terminal 172 to drive a plurality of electronic elements 22.

[0054] As shown in Figures 1 and 2, the second detection terminal 182 is located next to the second gate terminal 172 in the first direction x. The second detection terminal 182 is electrically connected to the second detection wiring 163 of the second wiring 16. The second detection terminal 182 is a metal lead made of a material including, for example, copper or a copper alloy. As shown in Figure 3, a portion of the second detection terminal 182 is covered by the sealing resin 50. Viewed in the first direction x, the second detection terminal 182 is L-shaped. As shown in Figure 4, the second detection terminal 182 includes a portion that stands upright in the thickness direction z (on the z1 side of the thickness direction z). This portion is exposed from the sealing resin 50. A voltage equivalent to the voltage applied to the main surface electrodes 222 of the plurality of electronic elements 22 is applied to the second detection terminal 182.

[0055] As shown in Figure 2, the multiple fifth wires 45 are individually conductively connected between the first gate terminal 171 and the first gate wiring 152, and between the first detection terminal 181 and the first detection wiring 153. As a result, the first gate terminal 171 is electrically connected to the gate electrodes 213 of the multiple electronic elements 21 via the first gate wiring 152. The first detection terminal 181 is electrically connected to the main surface electrodes 212 of the multiple electronic elements 21 via the first detection wiring 153.

[0056] Furthermore, as shown in Figure 2, the multiple fifth wires 45 are individually conductively joined between the second gate terminal 172 and the second gate wiring 162, and between the second detection terminal 182 and the second detection wiring 163. As a result, the second gate terminal 172 is electrically connected to the gate electrodes 223 of the multiple electronic elements 22 via the second gate wiring 162. The second detection terminal 182 is electrically connected to the main surface electrodes 222 of the multiple electronic elements 22 via the second detection wiring 163. The composition of the multiple fifth wires 45 includes, for example, gold. In addition, the composition of the multiple fifth wires 45 may include copper or aluminum.

[0057] As shown in Figures 1 and 2, the electronic device A10 further comprises four dummy terminals 19. Two of the four dummy terminals 19 are located on the opposite side of the first gate terminal 171 with respect to the first detection terminal 181 in the first direction x. The remaining two dummy terminals 19 are located on the opposite side of the second gate terminal 172 with respect to the second detection terminal 182 in the first direction x. The dummy terminals 19 are metal leads made of a material including, for example, copper or a copper alloy. The shape of each of the dummy terminals 19 is equal to the shape of the first gate terminal 171. A portion of each of the dummy terminals 19 is covered with sealing resin. The portion of each dummy terminal 19 that stands upright in the thickness direction z (on the z1 side of the thickness direction z) is exposed from the sealing resin 50.

[0058] As shown in Figures 1 and 2, the first terminal 112 is located on the opposite side of the plurality of electronic elements 22 from the plurality of electronic elements 21 in the first direction x. As shown in Figure 5, the first terminal 112 is conductively bonded to the main surface 111A of the conductive portion 111 via the first pillow material 113. Therefore, the first terminal 112 is located away from the conductive portion 111 in the thickness direction z. As shown in Figure 2, when viewed in the thickness direction z, the first terminal 112 overlaps the conductive portion 111. The composition of the first terminal 112 includes, for example, copper.

[0059] The first terminal 112 is electrically connected to the conductive part 111. Furthermore, the first terminal 112 is electrically connected to the back electrodes 211 of multiple electronic elements 21 via the conductive part 111. The first terminal 112 is the P terminal (positive electrode) to which the DC power supply voltage to be converted is applied.

[0060] As shown in Figure 5, a portion of the first terminal 112 is exposed from the sealing resin 50. A first mounting hole 112A is provided in the portion of the first terminal 112 that is exposed from the sealing resin 50. The first mounting hole 112A penetrates the first terminal 112 in the thickness direction z.

[0061] Each of the multiple fourth conductive members 14 is conductively bonded to the main surface electrode 212 of one of the multiple electronic elements 21 and to the main surface 131A of the conductive portion 131 via a conductive bonding layer 29, as shown in Figures 2, 5, 6, and 9. As a result, the conductive portion 131 is electrically connected to the main surface electrodes 212 of the multiple electronic elements 21. The multiple fourth conductive members 14 extend in the first direction x. The composition of the multiple third conductive members 134 includes, for example, copper. In the electronic device A10, each of the multiple fourth conductive members 14 is a metal lead. Alternatively, each of the multiple fourth conductive members 14 may be multiple wires.

[0062] As shown in Figures 1, 5, and 6, the main material 121 straddles the conductive portion 111 and the conductive portion 131, and is located away from the conductive portions 111 and 131 in the thickness direction z. The composition of the main material 121 includes, for example, copper. The main material 121 has a plurality of connecting portions 121A, a first connecting portion 121B, and a second connecting portion 121C.

[0063] As shown in Figures 5, 6, 8, and 10, each of the multiple connection portions 121A is electrically bonded to the main surface electrode 222 of one of the multiple electronic elements 22 via a conductive bonding layer 29. As a result, the main material 121 is electrically connected to the main surface electrode 222 of the multiple electronic elements 22. The multiple connection portions 121A extend in the first direction x.

[0064] As shown in Figures 1 and 7, the first connecting portion 121B extends in the second direction y. The multiple connecting portions 121A are connected to the first connecting portion 121B. The second connecting portion 121C is located in the first direction x, on the opposite side from the multiple connecting portions 121A with respect to the first connecting portion 121B. The second connecting portion 121C is connected to the first connecting portion 121B. The second connecting portion 121C extends in the first direction x. Viewed in the thickness direction z, the first connecting portion 121B and the second connecting portion 121C overlap the conductive portion 111. Therefore, viewed in the thickness direction z, the second conductive member 12 overlaps the first conductive member 11.

[0065] As shown in Figure 1, the second terminal 122 is located on the opposite side of the plurality of electronic elements 22 from the plurality of electronic elements 21 in the first direction x. The second terminal 122 is located away from the first terminal 112 in the second direction y. The second terminal 122 is located away from the conductive portion 111 in the thickness direction z. The composition of the second terminal 122 includes, for example, copper.

[0066] As shown in Figure 1, the second terminal 122 is connected to the second connecting portion 121C of the main material 121. As a result, the second terminal 122 is electrically connected to the main surface electrodes 222 of the multiple electronic elements 22 via the main material 121. Therefore, the second conductive member 12 is electrically connected to the main surface electrodes 222 of the multiple electronic elements 22. Furthermore, the second conductive member 12 is electrically connected to the multiple electronic elements 21 via the multiple electronic elements 22, the conductive portion 131, and the multiple fourth conductive members 14. The second terminal 122 is the N terminal (negative electrode) to which the DC power supply voltage to be converted is applied.

[0067] As shown in Figure 6, a portion of the second terminal 122 is exposed from the sealing resin 50. A second mounting hole 122A is provided in the portion of the second terminal 122 that is exposed from the sealing resin 50. The second mounting hole 122A penetrates the second terminal 122 in the thickness direction z.

[0068] As shown in Figures 1 and 2, the third terminal 132 is located on the opposite side of the first terminal 112 and the second terminal 122 in the first direction x with respect to the plurality of electronic elements 22. As shown in Figure 5, the third terminal 132 is conductively bonded to the main surface 131A of the conductive portion 131 via the second pillow material 133. Therefore, the third terminal 132 is located away from the conductive portion 131 in the thickness direction z. The composition of the third terminal 132 includes, for example, copper.

[0069] The third terminal 132 is electrically connected to the conductive portion 131. Furthermore, the third terminal 132 is electrically connected to the back electrodes 221 of the multiple electronic elements 22 via the conductive portion 131. The AC power converted by the multiple electronic elements 21 and 22 is output from the third terminal 132.

[0070] As shown in Figure 5, a portion of the third terminal 132 is exposed from the sealing resin 50. A third mounting hole 132A is provided in the portion of the third terminal 132 that is exposed from the sealing resin 50. The third mounting hole 132A penetrates the third terminal 132 in the thickness direction z.

[0071] As shown in Figure 6, the electronic element 23 is bonded to the main surface 111A of the conductive portion 111. In the electronic device A10, the electronic element 23 is a passive element, such as a silicon capacitor. The composition of the electronic element 23 includes silicon (Si). The electronic element 23 is rectangular when viewed in the thickness direction z.

[0072] As shown in Figure 11, the electronic element 23 has a first element surface 23A and a second element surface 23B. The first element surface 23A and the second element surface 23B are separated in the thickness direction z. The first element surface 23A faces the z1 side in the thickness direction z, and the second element surface 23B faces the z2 side in the thickness direction z.

[0073] As shown in Figure 11, the electronic element 23 has a first electrode 231 and a second electrode 232. The first electrode 231 is located on the second surface 23B of the element. The first electrode 231 faces the main surface 111A of the conductive portion 111. The second electrode 232 is located on the first surface 23A of the element (on the opposite side from the first electrode 231 in the thickness direction z).

[0074] As shown in Figure 11, a stress buffer layer 31 is located between the main surface 111A (conductive portion 111) and the first electrode 231 (electronic element 23) in the thickness direction z. The stress buffer layer 31 is conductive. The stress buffer layer 31 is conductively bonded to the main surface 111A of the conductive portion 111 via the first bonding layer 35. The stress buffer layer 31 is also conductively bonded to the first electrode 231 of the electronic element 23 via the second bonding layer 36. As a result, the first electrode 231 of the electronic element 23 is electrically connected to the first conductive member 11. The composition of the stress buffer layer 31 includes, for example, iron and nickel. The first bonding layer 35 and the second bonding layer 36 are, for example, solder. Alternatively, the first bonding layer 35 and the second bonding layer 36 may be sintered metal containing silver or the like, or a metallic bonding layer in which two metal layers in contact with each other are bonded by solid-phase diffusion. The thickness of the stress buffer layer 31 is thinner than the thickness of the conductive portion 111. The thickness of the first bonding layer 35 and the second bonding layer 36 is thinner than the thickness of the stress buffer layer 31.

[0075] The stress buffer layer 31 located between the conductive part 111 and the electronic element 23 has the same configuration as the stress buffer layer 31 located between the conductive part 111 and the electronic element 21, and the stress buffer layer 31 located between the conductive part 131 and the electronic element 22. The stress buffer layer 31 located between the conductive part 111 and the electronic element 23 has a first surface 311 and a second surface 312. The first surface 311 and the second surface 312 are separated in the thickness direction z. The first surface 311 faces the z1 side in the thickness direction z, and the second surface 312 faces the z2 side in the thickness direction z. In the electronic device A10, the area of ​​the second surface 312 is larger than the area of ​​the second surface 23B of the electronic element 23. Viewed in the thickness direction z, the second surface 312 overlaps with the entire second surface 23B of the element. Also, the area of ​​the second surface 312 is larger than the area of ​​the first surface 311. Viewed in the thickness direction z, the second surface 312 overlaps with the entire first surface 311. The area of ​​the first surface 311 is larger than the area of ​​the second surface 23B of the element. Viewed in the thickness direction z, the first surface 311 overlaps with the entire second surface 23B of the element.

[0076] In the electronic device A10, the linear expansion coefficient of the stress buffer layer 31 located between the conductive portion 111 and the electronic element 23 is smaller than that of the conductive portion 111. Also, the linear expansion coefficient of the stress buffer layer 31 is smaller than that of the electronic element 23. The linear expansion coefficient of the conductive portion 111 (copper) is 17.7×10 -6 / °C. The linear expansion coefficient of the electronic element 23 (silicon) is 3.9×10 -6 / °C. The linear expansion coefficient of the stress buffer layer 31 is preferably 3.0×10 -6 / °C or less. Such a stress buffer layer 31 includes, for example, an Invar material, which is an alloy of iron and nickel.

[0077] As shown in FIGS. 1 and 11, the plurality of sixth wires 46 are conductively joined to the second electrode of the electronic element 23 and the second terminal 122. Thereby, the second conduction member 12 is in conduction with the second electrode 232. The composition of the plurality of sixth wires includes, for example, gold. In addition, the composition of the plurality of sixth wires 46 may include copper or aluminum.

[0078] Referring to FIGS. 12 and 13, the stress buffer layer 31 will be described in more detail. FIGS. 12 and 13 show the stress buffer layer 31 located between the conductive portion 111 and the electronic element 23. Although detailed illustration description is omitted, the stress buffer layer 31 located between the conductive portion 111 and the electronic element 21, and the stress buffer layer 31 located between the conductive portion 131 and the electronic element 22 have the same configuration as the stress buffer layer 31 located between the conductive portion 111 and the electronic element 23 shown in FIGS. 12 and 13.

[0079] [[ID=>

[0080] ​On each first side surface 313, the line segment connecting the first edge 313a and the second edge 313b, viewed in the second direction y, is inclined with respect to the thickness direction z. On each first side surface 313, the second edge 313b is located further outward than the first edge 313a in the first direction x. The inclination angle α1 of the line segment connecting the first edge 313a and the second edge 313b with respect to the main surface 111A, viewed in the second direction y, is, for example, between 20 degrees and 90 degrees. In the electronic device A10, the pair of first side surfaces 313 are located closer to the z2 side of the thickness direction z as they move outward in the first direction x. Each first side surface 313 is a flat surface inclined with respect to the thickness direction z.

[0081] As shown in Figure 13, the pair of second sides 314 are located at one end in the second direction y and the other end in the second direction y. Each of the pair of second sides 314 has a third edge 314a and a fourth edge 314b. The third edge 314a connects to the first surface 311, and the fourth edge 314b connects to the second surface 312. Each of the third edge 314a and the fourth edge 314b extends in the first direction x.

[0082] On each second side surface 314, the line segment connecting the third edge 314a and the fourth edge 314b, viewed in the first direction x, is inclined with respect to the thickness direction z. On each second side surface 314, the fourth edge 314b is located further outward than the third edge 314a in the first direction x. The inclination angle α2 of the line segment connecting the third edge 314a and the fourth edge 314b with respect to the main surface 111A, viewed in the first direction x, is, for example, between 20 degrees and 90 degrees. In the electronic device A10, the pair of second side surfaces 314 are located closer to the z2 side of the thickness direction z as they move outward in the second direction y. Each second side surface 314 is a flat surface inclined with respect to the thickness direction z.

[0083] As shown in Figures 5 to 8, the sealing resin 50 covers the conductive part 111, the main material 121, the conductive part 131, the first wiring 15, the second wiring 16, the multiple electronic elements 21, the multiple electronic elements 22, the electronic element 23, and the stress buffer layer 31. Furthermore, the sealing resin 50 covers a portion of each of the first terminal 112, the second terminal 122, the third terminal 132, the first gate terminal 171, the second gate terminal 172, the first detection terminal 181, the second detection terminal 182, and the multiple dummy terminals 19. The sealing resin 50 has electrical insulating properties. The sealing resin 50 is made of a material including, for example, black epoxy resin. As shown in Figures 3 and 4, the sealing resin 50 has a top surface 51, a bottom surface 52, a pair of first resin side surfaces 53, and a pair of second resin side surfaces 54.

[0084] As shown in Figures 5 to 8, the top surface 51 faces the same side as the main surface 111A of the conductive portion 111 in the thickness direction z (the z1 side in the thickness direction z). The bottom surface 52 faces the opposite side from the top surface 51 in the thickness direction z (the z2 side in the thickness direction z). As shown in Figure 3, a portion of the heat dissipation layer 103 of the pair of support members 10 is exposed from the bottom surface 52.

[0085] As shown in Figures 5 and 6, the pair of first resin sides 53 are located apart from each other in a first direction x and are connected to a top surface 51 and a bottom surface 52. Parts of the first terminal 112 and the second terminal 122 are exposed from one of the pair of first resin sides 53. Parts of the third terminal 132 are exposed from the other of the pair of first resin sides 53. As shown in Figures 7 and 8, the pair of second resin sides 54 are located apart from each other in a second direction y and are connected to a top surface 51 and a bottom surface 52. Parts of the first gate terminal 171, the second gate terminal 172, the first detection terminal 181, the second detection terminal 182, and the plurality of dummy terminals 19 are exposed from one of the pair of second resin sides 54.

[0086] Next, the operation of electronic device A10 will be explained.

[0087] The electronic device A10 includes a stress buffer layer 31 located between the main surface 111A (131A) of the conductive portion 111 (113) and the electronic element 23 (21, 22) in the thickness direction z. The area of ​​the second surface 312 of the stress buffer layer 31 facing the z2 side in the thickness direction z is larger than the area of ​​the second element surface 23B (21B, 22B) of the electronic element 23 (21, 22) facing the z2 side in the thickness direction z. As a result, the bonding area of ​​the stress buffer layer 31 to the conductive portion 111 (131) is larger than the bonding area of ​​the electronic element 23 (21, 21) to the stress buffer layer 31. Also, when viewed in the thickness direction z, the second surface 312 of the stress buffer layer 31 overlaps with the entire second element surface 23B (21B, 22B). With this configuration including the stress buffer layer 31, the heat generated in the electronic elements 23 (21, 22) can be efficiently dissipated to the conductive part 111 (131) via the stress buffer layer 31. As a result, the thermal stress acting on the electronic elements 23 (21, 22) can be reduced in the electronic device A10.

[0088] The area of ​​the second surface 312 of the stress buffer layer 31 is larger than the area of ​​the first surface 311 facing the z1 side in the thickness direction z of the stress buffer layer 31. Viewed in the thickness direction z, the second surface 312 overlaps with the entire first surface 311. With this configuration, the heat transferred from the electronic elements 23 (21, 22) to the stress buffer layer 31 can be more efficiently dissipated to the conductive portion 111 (131). This is more preferable in reducing the thermal stress acting on the electronic elements 23 (21, 22).

[0089] The stress buffer layer 31 has a first surface 313 located at the end of the first direction x, and a second surface 314 located at the end of the second direction y. The second edge 313b of the first surface 313 that connects to the second surface 312 is located further out in the first direction x than the first edge 313a of the first surface 313 that connects to the first surface 311. Looking in the second direction y, the inclination angle α1 of the line segment connecting the first edge 313a and the second edge 313b with respect to the main surface 111A is between 20 degrees and 90 degrees. The fourth edge 314b of the second surface 314 that connects to the second surface 312 is located further out in the second direction y than the third edge 314a of the second surface 314 that connects to the first surface 311. Looking in the first direction x, the inclination angle α2 of the line segment connecting the third edge 314a and the fourth edge 314b with respect to the main surface 111A is between 20 degrees and 90 degrees. This configuration makes it possible to reduce the thermal stress acting on the electronic elements 23 (21, 22) while suppressing the area of ​​the second surface 312, which is the bottom surface of the stress buffer layer 31 (i.e., the size when viewed in the thickness direction z of the stress buffer layer 31) from becoming excessive.

[0090] In the electronic device A10, the coefficient of thermal expansion of the stress buffer layer 31 interposed between the conductive part 111 (131) and the electronic element 23 (21, 22) is smaller than the coefficient of thermal expansion of both the conductive part 111 (131) and the electronic element 23 (21, 22). With this configuration, the difference between the coefficient of thermal expansion of the electronic element 23 (21, 22) and the coefficient of thermal expansion of the stress buffer layer 31 can be made smaller than the difference between the coefficient of thermal expansion of the electronic element 23 (21, 22) and the coefficient of thermal expansion of the conductive part 111 (131). As a result, the thermal stress acting on the electronic element 23 (21, 22) can be reduced compared to the case where the electronic element 23 (21, 22) is directly joined to the conductive part 111 (131).

[0091] The electronic device A10 includes a first bonding layer 35 that electrically bonds the conductive part 111 (131) and the stress buffer layer 31, and a second bonding layer 36 that electrically bonds the stress buffer layer 31 and the electronic elements 23 (21, 22). The thickness of the first bonding layer 35 and the second bonding layer 36 is thinner than the thickness of the stress buffer layer 31. With this configuration, the thermal resistance in the conductive path between the electronic elements 23 (21, 22) and the conductive part 111 (131) can be reduced.

[0092] Figures 14 to 40 show modified and other embodiments of the electronic device of the present disclosure. In these figures, elements identical or similar to those in the above embodiments are denoted by the same reference numerals, and redundant explanations are omitted. Furthermore, the configurations of the parts in each modified and other embodiment can be appropriately combined with each other to the extent that no technical inconsistencies arise.

[0093] First Modification: Figures 14 and 15 show a first modification of the electronic device A10. Figure 14 is a partially enlarged cross-sectional view of the electronic device A11 according to this modification, and corresponds to the cross-section shown in Figure 12. Figure 15 is a cross-sectional view along the line XV-XV in Figure 14. In the electronic device A11, the configuration of the stress buffer layer 31 differs from that of the electronic device A10 of the above embodiment.

[0094] In the modified electronic device A11, the area of ​​the first surface 311 of the stress buffer layer 31 is the same as the area of ​​the second surface 23B of the electronic element 23. Viewed in the thickness direction z, the first surface 311 overlaps with the entire second surface 23B of the element. Note that the fact that the area of ​​the first surface 311 is the same as the area of ​​the second surface 23B of the element, and that the first surface 311 overlaps with the entire second surface 23B of the element when viewed in the thickness direction z, includes some errors that may occur due to the manufacturing precision of the electronic device A11.

[0095] Figures 14 and 15 show the stress buffer layer 31 located between the conductive part 111 and the electronic element 23. Although a detailed illustration is omitted, the stress buffer layer 31 located between the conductive part 111 and the electronic element 21, and the stress buffer layer 31 located between the conductive part 131 and the electronic element 22 may have the same configuration as the stress buffer layer 31 located between the conductive part 111 and the electronic element 23 shown in Figures 14 and 15.

[0096] In the electronic device A11, the area of ​​the second surface 312 of the stress buffer layer 31 facing z2 in the thickness direction z is larger than the area of ​​the second surface 23B (21B, 22B) of the electronic element 23 (21, 22) facing z2 in the thickness direction z. As a result, the bonding area of ​​the stress buffer layer 31 to the conductive part 111 (131) is larger than the bonding area of ​​the electronic element 23 (21, 21) to the stress buffer layer 31. Also, when viewed in the thickness direction z, the second surface 312 of the stress buffer layer 31 overlaps with the entire second surface 23B (21B, 22B) of the element. With this configuration, the heat generated in the electronic element 23 (21, 22) can be efficiently dissipated to the conductive part 111 (131) via the stress buffer layer 31. As a result, in the electronic device A11, it is possible to reduce the thermal stress acting on the electronic element 23 (21, 22). In addition, the electronic device A11 provides the same effects and advantages as the electronic device A10 in the above embodiment.

[0097] Second Modification: Figures 16 and 17 show a second modification of the electronic device A10. Figure 16 is a partially enlarged cross-sectional view of the electronic device A12 according to this modification, and corresponds to the cross-section shown in Figure 12. Figure 17 is a cross-sectional view along the line XVII-XVII in Figure 16. In the electronic device A12, the configuration of the stress buffer layer 31 differs from that of the electronic device A10 in the above embodiment.

[0098] In the modified electronic device A12, as shown in Figure 16, each of the pair of first side surfaces 313 has a portion connected to the first edge 313a and inclined with respect to the thickness direction z, a flat portion facing the z1 side of the thickness direction z, and a portion connected to the second edge 313b and inclined with respect to the thickness direction z. Each first side surface 313 is located on the z2 side of the thickness direction z as it moves outward in the first direction x. In the electronic device A12, each first side surface 313 is stepped. In the electronic device A12, as shown in Figure 17, each of the pair of second side surfaces 314 has a portion connected to the third edge 314a and inclined with respect to the thickness direction z, a flat portion facing the z1 side of the thickness direction z, and a portion connected to the fourth edge 314b and inclined with respect to the thickness direction z. Each second side surface 314 is located on the z2 side of the thickness direction z as it moves outward in the second direction y. In the electronic device A12, each second side surface 314 is stepped. While the first side surface 313 and the second side surface 314 are each stepped with two steps, they are not limited to this and may have three or more steps.

[0099] Figures 16 and 17 show the stress buffer layer 31 located between the conductive part 111 and the electronic element 23. Although a detailed illustration is omitted, the stress buffer layer 31 located between the conductive part 111 and the electronic element 21, and the stress buffer layer 31 located between the conductive part 131 and the electronic element 22 may have the same configuration as the stress buffer layer 31 located between the conductive part 111 and the electronic element 23 shown in Figures 16 and 17.

[0100] In the electronic device A12, the area of ​​the second surface 312 of the stress buffer layer 31 facing z2 in the thickness direction z is larger than the area of ​​the second surface 23B (21B, 22B) of the electronic element 23 (21, 22) facing z2 in the thickness direction z. As a result, the bonding area of ​​the stress buffer layer 31 to the conductive part 111 (131) is larger than the bonding area of ​​the electronic element 23 (21, 21) to the stress buffer layer 31. Also, when viewed in the thickness direction z, the second surface 312 of the stress buffer layer 31 overlaps with the entire second surface 23B (21B, 22B) of the element. With this configuration, the heat generated in the electronic element 23 (21, 22) can be efficiently dissipated to the conductive part 111 (131) via the stress buffer layer 31. As a result, the thermal stress acting on the electronic element 23 (21, 22) can be reduced in the electronic device A12. In addition, the electronic device A12 provides the same effects and benefits as the electronic device A10 in the above embodiment.

[0101] Third Modification: Figures 18 and 19 show a third modification of the electronic device A10. Figure 18 is a partially enlarged cross-sectional view of the electronic device A13 according to this modification, and corresponds to the cross-section shown in Figure 12. Figure 19 is a cross-sectional view along the line XIX-XIX in Figure 18. In the electronic device A13, the configuration of the stress buffer layer 31 differs from that of the electronic device A12 of the second modification described above.

[0102] In the modified electronic device A13, the area of ​​the first surface 311 of the stress buffer layer 31 is the same as the area of ​​the second surface 23B of the electronic element 23. Viewed in the thickness direction z, the first surface 311 overlaps with the entire second surface 23B of the element. Note that the fact that the area of ​​the first surface 311 is the same as the area of ​​the second surface 23B of the element, and that the first surface 311 overlaps with the entire second surface 23B of the element when viewed in the thickness direction z, includes some errors that may occur due to the manufacturing precision of the electronic device A13.

[0103] Figures 18 and 19 show the stress buffer layer 31 located between the conductive part 111 and the electronic element 23. Although a detailed illustration is omitted, the stress buffer layer 31 located between the conductive part 111 and the electronic element 21, and the stress buffer layer 31 located between the conductive part 131 and the electronic element 22 may have the same configuration as the stress buffer layer 31 located between the conductive part 111 and the electronic element 23 shown in Figures 18 and 19.

[0104] In the electronic device A13, the area of ​​the second surface 312 of the stress buffer layer 31 facing z2 in the thickness direction z is larger than the area of ​​the second surface 23B (21B, 22B) of the electronic element 23 (21, 22) facing z2 in the thickness direction z. As a result, the bonding area of ​​the stress buffer layer 31 to the conductive part 111 (131) is larger than the bonding area of ​​the electronic element 23 (21, 21) to the stress buffer layer 31. Also, when viewed in the thickness direction z, the second surface 312 of the stress buffer layer 31 overlaps with the entire second surface 23B (21B, 22B) of the element. With this configuration, the heat generated in the electronic element 23 (21, 22) can be efficiently dissipated to the conductive part 111 (131) via the stress buffer layer 31. As a result, in the electronic device A13, it is possible to reduce the thermal stress acting on the electronic element 23 (21, 22). In addition, the electronic device A13 provides the same effects and benefits as the electronic device A10 in the above embodiment.

[0105] Fourth Modification: Figures 20 and 21 show a fourth modification of the electronic device A10. Figure 20 is a partially enlarged cross-sectional view of the electronic device A14 according to this modification, and corresponds to the cross-section shown in Figure 12. Figure 21 is a cross-sectional view along the line XXI-XXI in Figure 20. In the electronic device A14, the configuration of the stress buffer layer 31 differs from that of the electronic device A10 in the above embodiment.

[0106] In the modified electronic device A14, as shown in Figure 20, each of the pair of first side surfaces 313 has a portion connected to the first edge 313a and inclined with respect to the thickness direction z, and a portion connected to the second edge 313b and inclined with respect to the thickness direction z. In each first side surface 313, the portion connected to the first edge 313a and inclined with respect to the thickness direction z is located on the z2 side of the thickness direction z as it moves outward in the first direction x. In each first side surface 313, the portion connected to the second edge 313b and inclined with respect to the thickness direction z is located on the z1 side of the thickness direction z as it moves outward in the first direction x. As a result, in each first side surface 313, the portion connected to the first edge 313a and inclined with respect to the thickness direction z and the portion connected to the second edge 313b and inclined with respect to the thickness direction z are in opposite directions with respect to the thickness direction z. In the electronic device A14, as shown in Figure 21, each of the pair of second sides 314 has a portion connected to the third edge 314a and inclined with respect to the thickness direction z, and a portion connected to the fourth edge 314b and inclined with respect to the thickness direction z. In each second side 314, the portion connected to the third edge 314a and inclined with respect to the thickness direction z is located on the z2 side of the thickness direction z as it moves outward in the second direction y. In each second side 314, the portion connected to the fourth edge 314b and inclined with respect to the thickness direction z is located on the z1 side of the thickness direction z as it moves outward in the second direction y. As a result, in each second side 314, the portion connected to the third edge 314a and inclined with respect to the thickness direction z and the portion connected to the fourth edge 314b and inclined with respect to the thickness direction z are inclined in opposite directions with respect to the thickness direction z.

[0107] In the electronic device A14, the area of ​​the second surface 312 is larger than the area of ​​the second surface 23B of the electronic element 23. Viewed in the thickness direction z, the second surface 312 overlaps with the entire second surface 23B of the element. Also, the area of ​​the second surface 312 is larger than the area of ​​the first surface 311. Viewed in the thickness direction z, the second surface 312 overlaps with the entire first surface 311. The area of ​​the first surface 311 is larger than the area of ​​the second surface 23B of the element. Viewed in the thickness direction z, the first surface 311 overlaps with the entire second surface 23B of the element.

[0108] Figures 20 and 21 show the stress buffer layer 31 located between the conductive part 111 and the electronic element 23. Although a detailed illustration is omitted, the stress buffer layer 31 located between the conductive part 111 and the electronic element 21, and the stress buffer layer 31 located between the conductive part 131 and the electronic element 22 may have the same configuration as the stress buffer layer 31 located between the conductive part 111 and the electronic element 23 shown in Figures 20 and 21.

[0109] In the electronic device A14, the area of ​​the second surface 312 of the stress buffer layer 31 facing z2 in the thickness direction z is larger than the area of ​​the second surface 23B (21B, 22B) of the electronic element 23 (21, 22) facing z2 in the thickness direction z. As a result, the bonding area of ​​the stress buffer layer 31 to the conductive part 111 (131) is larger than the bonding area of ​​the electronic element 23 (21, 21) to the stress buffer layer 31. Also, when viewed in the thickness direction z, the second surface 312 of the stress buffer layer 31 overlaps with the entire second surface 23B (21B, 22B) of the element. With this configuration, the heat generated in the electronic element 23 (21, 22) can be efficiently dissipated to the conductive part 111 (131) via the stress buffer layer 31. As a result, in the electronic device A14, it is possible to reduce the thermal stress acting on the electronic element 23 (21, 22). In addition, the electronic device A14 provides the same effects and benefits as the electronic device A10 in the above embodiment.

[0110] Fifth Modification: Figures 22 and 23 show a fifth modification of the electronic device A10. Figure 22 is a partially enlarged cross-sectional view of the electronic device A15 according to this modification, and corresponds to the cross-section shown in Figure 12. Figure 23 is a cross-sectional view along the line XXIII-XXIII in Figure 22. In the electronic device A15, the configuration of the stress buffer layer 31 differs from that of the electronic device A10 in the above embodiment.

[0111] In the modified electronic device A15, as shown in Figure 22, each of the pair of first side surfaces 313 is located on the z1 side of the thickness direction z as it moves outward in the first direction x. Each first side surface 313 is a flat surface inclined with respect to the thickness direction z. Compared to the electronic device A10 of the above embodiment, the direction of inclination of each first side surface 313 with respect to the thickness direction z is opposite. As shown in Figure 23, each of the pair of second side surfaces 314 is located on the z1 side of the thickness direction z as it moves outward in the second direction y. Each second side surface 314 is a flat surface inclined with respect to the thickness direction z. Compared to the electronic device A10 of the above embodiment, the direction of inclination of each second side surface 314 with respect to the thickness direction z is opposite.

[0112] In the electronic device A15, the area of ​​the second surface 312 is larger than the area of ​​the second surface 23B of the electronic element 23. Viewed in the thickness direction z, the second surface 312 overlaps with the entire second surface 23B of the element. The area of ​​the first surface 311 is larger than the area of ​​the second surface 23B of the element. Viewed in the thickness direction z, the first surface 311 overlaps with the entire second surface 23B of the element.

[0113] Figures 22 and 23 show the stress buffer layer 31 located between the conductive part 111 and the electronic element 23. Although a detailed illustration is omitted, the stress buffer layer 31 located between the conductive part 111 and the electronic element 21, and the stress buffer layer 31 located between the conductive part 131 and the electronic element 22 may have the same configuration as the stress buffer layer 31 located between the conductive part 111 and the electronic element 23 shown in Figures 22 and 23.

[0114] In the electronic device A15, the area of ​​the second surface 312 of the stress buffer layer 31 facing z2 in the thickness direction z is larger than the area of ​​the second surface 23B (21B, 22B) of the electronic element 23 (21, 22) facing z2 in the thickness direction z. As a result, the bonding area of ​​the stress buffer layer 31 to the conductive part 111 (131) is larger than the bonding area of ​​the electronic element 23 (21, 21) to the stress buffer layer 31. Also, when viewed in the thickness direction z, the second surface 312 of the stress buffer layer 31 overlaps with the entire second surface 23B (21B, 22B) of the element. With this configuration, the heat generated in the electronic element 23 (21, 22) can be efficiently dissipated to the conductive part 111 (131) via the stress buffer layer 31. As a result, in the electronic device A15, it is possible to reduce the thermal stress acting on the electronic element 23 (21, 22). Furthermore, electronic device A15 provides the same effects and advantages as electronic device A10 in the above embodiment, within the same range of configuration as electronic device A10.

[0115] Sixth Modification: Figure 24 shows a sixth modification of the electronic device A10. Figure 24 is a partially enlarged cross-sectional view of the electronic device A16 according to this modification, and corresponds to the cross-section shown in Figure 12. In the electronic device A16, the configuration of the stress buffer layer 31 differs from that of the electronic device A10 in the above embodiment.

[0116] In the modified electronic device A16, as shown in Figure 24, the pair of first side surfaces 313 are located on the z2 side of the thickness direction z as they move outward in the first direction x. Each first side surface 313 is a concave curved surface when viewed in the second direction y. Although not shown, the pair of second side surfaces 314 may have the same shape as the first side surfaces 313. In this case, each of the pair of second side surfaces 314 is a concave curved surface when viewed in the first direction x. The modified electronic device A16 also provides the same effects and advantages as the electronic device A10 of the above embodiment.

[0117] Seventh Modification: Figure 25 shows a seventh modification of the electronic device A10. Figure 25 is a partially enlarged cross-sectional view of the electronic device A17 according to this modification, and corresponds to the cross-section shown in Figure 12. In the electronic device A17, the configuration of the stress buffer layer 31 differs from that of the electronic device A10 of the above embodiment.

[0118] In the modified electronic device A17, as shown in Figure 25, one of the pair of first side surfaces 313 is an inclined surface located towards the z2 side of the thickness direction z as it moves outward in the first direction x. The other of the pair of first side surfaces 313 is not inclined with respect to the thickness direction z. Although not shown, the pair of second side surfaces 314 may have the same shape as the pair of first side surfaces 313 shown in Figure 25. In the modified electronic device A17, within the same range of configuration as the electronic device A10 of the above embodiment, the same effects and advantages as the electronic device A10 are achieved.

[0119] Second Embodiment: Figures 26 to 32 show an electronic device A20 according to the second embodiment of the present disclosure. Figure 26 is a plan view of the electronic device A20 of this embodiment, showing the encapsulating resin 50 through which light has been seen. Figure 27 is a plan view of the electronic device A20, showing the encapsulating resin 50, the second conductive member 12, the first terminal 112, and the third terminal 132 through which light has been seen. Figure 28 is a cross-sectional view taken along the line XXVIII-XXVIII in Figure 26. Figure 29 is a cross-sectional view taken along the line XXIX-XXIX in Figure 26. Figure 30 is a partially enlarged view of Figure 29. Figure 31 is a partially enlarged view of Figure 30. Figure 32 is a cross-sectional view taken along the line XXXII-XXXII in Figure 31. In Figure 26, the outline of the encapsulating resin 50 through which light has been seen is shown by dashed lines. In Figure 27, the outlines of the permeated sealing resin 50, second conductive member 12, first terminal 112, and third terminal 132 are shown by dashed lines. In Figures 31 and 32, the sealing resin 50, first wire 41, second terminal 122, and the spacer 24 described later are omitted.

[0120] In electronic device A20, the configuration of the electronic element 23 differs from that of electronic device A10 in the above embodiment, and various modifications have been made accordingly.

[0121] In the electronic device A20, the electronic element 23 has a stacked structure of multiple conductive layers and multiple dielectric layers, and this internal structure gives it the function of a capacitor. In this embodiment, the electronic element 23 extends elongated in the second direction y. When viewed in the first direction x, the electronic element 23 overlaps with the entirety of the multiple electronic elements 21.

[0122] The electronic element 23 has a first electrode 231 positioned on the second surface 23B of the element and a second electrode 232 positioned on the first surface 23A of the element. The second electrode 232 extends in the second direction y. The second electrode 232 is positioned biased toward the side of the first surface 23A of the element where the first terminal 112 and the second terminal 122 are located in the first direction. In this embodiment, a first gate wiring 152 and a first detection wiring 153 are formed on the first surface 23A of the electronic element 23. Each of the first gate wiring 152 and the first detection wiring 153 extends in the second direction y. The first gate wiring 152 and the first detection wiring 153 are spaced apart from each other in the first direction x.

[0123] In the electronic device A10 of the above embodiment, a first wiring 15 made of a DBC substrate or the like was arranged between the electronic element 23 and the plurality of electronic elements 21 in the first direction x. In contrast, in this embodiment, the electronic element 23 plays the role of a wiring substrate, similar to the first wiring 15 in the above embodiment.

[0124] As shown in Figures 28 to 30, a stress buffer layer 31 is located between the main surface 111A (conductive portion 111) and the first electrode 231 (electronic element 23) in the thickness direction z. The stress buffer layer 31 is conductive. The stress buffer layer 31 is conductively bonded to the main surface 111A of the conductive portion 111 via the first bonding layer 35. The stress buffer layer 31 is also conductively bonded to the first electrode 231 of the electronic element 23 via the second bonding layer 36. As a result, the first electrode 231 of the electronic element 23 is electrically connected to the first conductive member 11. The composition of the stress buffer layer 31 includes, for example, iron and nickel. The first bonding layer 35 and the second bonding layer 36 are, for example, solder. Alternatively, the first bonding layer 35 and the second bonding layer 36 may be sintered metals containing silver or the like, or metallic bonding layers in which two metal layers in contact with each other are bonded by solid-phase diffusion. The thickness of the stress buffer layer 31 is thinner than the thickness of the conductive portion 111. The thickness of the first bonding layer 35 and the second bonding layer 36 are each thinner than the thickness of the stress buffer layer 31.

[0125] The stress buffer layer 31 has a first surface 311 and a second surface 312. The first surface 311 and the second surface 312 are separated in the thickness direction z. The first surface 311 faces the z1 side in the thickness direction z, and the second surface 312 faces the z2 side in the thickness direction z. In the electronic device A20, the area of ​​the second surface 312 is larger than the area of ​​the second surface 21B of the electronic element 21. In the thickness direction z, the second surface 312 overlaps with the entire second surface 21B of the element. Also, the area of ​​the second surface 312 is larger than the area of ​​the first surface 311. In the thickness direction z, the second surface 312 overlaps with the entire first surface 311. The area of ​​the first surface 311 is larger than the area of ​​the second surface 21B of the element. Viewed in the thickness direction z, the first surface 311 overlaps with the entirety of the second surface 21B of the element.

[0126] The stress buffer layer 31 located between the conductive portion 111 and the electronic element 23 has a first surface 311 and a second surface 312. The first surface 311 and the second surface 312 are separated in the thickness direction z. The first surface 311 faces the z1 side in the thickness direction z, and the second surface 312 faces the z2 side in the thickness direction z. In the electronic device A20, the area of ​​the second surface 312 is larger than the area of ​​the second surface 23B of the electronic element 23. In the thickness direction z, the second surface 312 overlaps with the entire second surface 23B of the element. Also, the area of ​​the second surface 312 is larger than the area of ​​the first surface 311. In the thickness direction z, the second surface 312 overlaps with the entire first surface 311. In the electronic device A20, the area of ​​the first surface 311 is the same as the area of ​​the second surface 23B of the element. Viewed in the thickness direction z, the first surface 311 overlaps with the entire second surface 23B of the element. Note that the fact that the area of ​​the first surface 311 is the same as the area of ​​the second surface 23B of the element, and that the first surface 311 overlaps with the entire second surface 23B of the element in the thickness direction z, includes some errors that may occur due to the manufacturing precision of the electronic device A20.

[0127] In the electronic device A20, the first connecting portion 121B of the main material 121 overlaps with the second electrode 232 of the electronic element 23 when viewed in the thickness direction z. As shown in Figures 28 to 30, the first connecting portion 121B is conductively joined to the second electrode 232 via conductive spacers 24. In this embodiment, a plurality of spacers 24 are interposed between the second electrode 232 and the first connecting portion 121B. These plurality of spacers 24 are arranged along the second direction y. Note that the configuration of the spacers 24 is not limited to the illustrated example, and may be configured to extend elongated in the second direction y.

[0128] Referring to Figures 31 and 32, the stress buffer layer 31 located between the conductive portion 111 and the electronic element 23 will be described in more detail. The stress buffer layer 31 has a pair of first surfaces 313 and a pair of second surfaces 314. The pair of first surfaces 313 are located at one end in the first direction x and the other end in the first direction x. Each of the pair of first surfaces 313 has a first edge 313a and a second edge 313b. The first edge 313a connects to the first surface 311, and the second edge 313b connects to the second surface 312. Each of the first edge 313a and the second edge 313b extends in the second direction y.

[0129] On each first side surface 313, the line segment connecting the first edge 313a and the second edge 313b, viewed in the second direction y, is inclined with respect to the thickness direction z. On each first side surface 313, the second edge 313b is located further outward than the first edge 313a in the first direction x. The inclination angle α1 of the line segment connecting the first edge 313a and the second edge 313b with respect to the main surface 111A, viewed in the second direction y, is, for example, between 20 degrees and 90 degrees. In the electronic device A20, the pair of first side surfaces 313 are located closer to the z2 side of the thickness direction z as they move outward in the first direction x. Each first side surface 313 is a flat surface inclined with respect to the thickness direction z.

[0130] As shown in Figure 32, the pair of second sides 314 are located at one end in the second direction y and the other end in the second direction y. Each of the pair of second sides 314 has a third edge 314a and a fourth edge 314b. The third edge 314a connects to the first surface 311, and the fourth edge 314b connects to the second surface 312. Each of the third edge 314a and the fourth edge 314b extends in the first direction x.

[0131] On each second side surface 314, the line segment connecting the third edge 314a and the fourth edge 314b, viewed in the first direction x, is inclined with respect to the thickness direction z. On each second side surface 314, the fourth edge 314b is located further outward than the third edge 314a in the first direction x. The inclination angle α2 of the line segment connecting the third edge 314a and the fourth edge 314b with respect to the main surface 111A, viewed in the first direction x, is, for example, between 20 degrees and 90 degrees. In the electronic device A20, the pair of second side surfaces 314 are located closer to the z2 side of the thickness direction z as they move outward in the second direction y. Each second side surface 314 is a flat surface inclined with respect to the thickness direction z.

[0132] In the electronic device A20, the area of ​​the second surface 312 of the stress buffer layer 31 facing z2 in the thickness direction z is larger than the area of ​​the second surface 23B of the electronic element 23 facing z2 in the thickness direction z. As a result, the bonding area of ​​the stress buffer layer 31 to the conductive part 111 is larger than the bonding area of ​​the electronic element 23 to the stress buffer layer 31. Also, when viewed in the thickness direction z, the second surface 312 of the stress buffer layer 31 overlaps with the entire second surface 23B of the element. With this configuration, the heat generated in the electronic element 23 can be efficiently dissipated to the conductive part 111 via the stress buffer layer 31. As a result, the thermal stress acting on the electronic element 23 can be reduced in the electronic device A20. Furthermore, the electronic device A20 exhibits the same effects as the electronic device A10 of the above embodiment.

[0133] Third Embodiment: Figures 33 to 40 show an electronic device A30 according to the third embodiment of the present disclosure. The electronic device A30 of this embodiment is generally used in power conversion circuits such as inverters. The package type of the electronic device A30 is TO (Transistor Outline). The electronic device A30 comprises an electronic element 25, a first lead 61, a second lead 62, a third lead 63, a stress buffer layer 31, a first bonding layer 35, a second bonding layer 36, wires 47, 48, and a sealing resin 50.

[0134] Figure 33 is a perspective view showing the electronic device A30. Figure 34 is a plan view showing the electronic device A30. Figure 35 is a plan view showing the electronic device A30 with the sealing resin 50 visible through it. Figure 36 is a cross-sectional view along the line XXXVI-XXXVI in Figure 35. Figure 37 is a cross-sectional view along the line XXXVII-XXXVII in Figure 35. Figure 38 is a cross-sectional view along the line XXXVIII-XXXVIII in Figure 35. Figure 39 is a partially enlarged view of Figure 38. Figure 40 is a cross-sectional view along the line XL-XL in Figure 39. In Figure 35, the outline of the transparent sealing resin 50 is shown by dashed lines. In Figures 39 and 40, the sealing resin 50 is omitted.

[0135] In describing the electronic device A30, for convenience, the direction normal to the main surface 111A of the die pad 611, which will be described later, is an example of the "thickness direction" in this disclosure and is referred to as the "thickness direction z". The direction perpendicular to the thickness direction z is an example of the "first direction" in this disclosure and is referred to as the "first direction x". The direction perpendicular to both the thickness direction z and the first direction x is an example of the "second direction" in this disclosure and is referred to as the "second direction y". Furthermore, one side of the thickness direction z corresponds to the "one side of the thickness direction" in this disclosure and is referred to as the "z1 side of the thickness direction z", and the other side of the thickness direction z corresponds to the "other side of the thickness direction" in this disclosure and is referred to as the "z2 side of the thickness direction z".

[0136] The electronic element 25 is a switching element, such as a MOSFET. Alternatively, the electronic element 25 may be a field-effect transistor including a MISFET, or a bipolar transistor such as an IGBT. In the description of the electronic device A30, the electronic element 25 is an n-channel, vertically structured MOSFET. The electronic element 25 includes a compound semiconductor substrate. The composition of the compound semiconductor substrate includes silicon carbide. The electronic element 25 is rectangular when viewed in the thickness direction z.

[0137] As shown in Figures 35 to 40, the electronic element 25 has a first element surface 25A and a second element surface 25B. The first element surface 25A and the second element surface 25B are separated in the thickness direction z. The first element surface 25A faces the z1 side in the thickness direction z, and the second element surface 25B faces the z2 side in the thickness direction z.

[0138] The electronic element 25 has a back electrode 251, a main electrode 252, and a gate electrode 253. The back electrode 251 is located on the second surface 21B of the element. The back electrode 251 is located on the side facing the main surface 611A of the die pad 611, which will be described later. A current corresponding to the power before it is converted by the electronic element 25 flows through the back electrode 251. In other words, the back electrode 251 corresponds to the drain electrode of the electronic element 25.

[0139] The main surface electrode 252 is positioned on the first surface 25A of the element (on the opposite side from the back surface electrode 251 in the thickness direction z). A current corresponding to the power converted by the electronic element 21 flows through the main surface electrode 252. In other words, the main surface electrode 252 corresponds to the source electrode of the electronic element 25.

[0140] As shown in Figures 35 and 37, the gate electrode 253 is located on the first surface 25A of the element (on the same side as the main surface electrode 252 in the thickness direction z). A gate voltage is applied to the gate electrode 253 to drive the electronic element 25. In the thickness direction z, the area of ​​the gate electrode 253 is smaller than the area of ​​the main surface electrode 252.

[0141] The first lead 61, the second lead 62, and the third lead 63 are obtained from the same lead frame. The constituent material of the lead frame is copper or a copper alloy. Therefore, the composition of each of the first lead 61, the second lead 62, and the third lead 63 includes copper.

[0142] As shown in Figures 35 to 38, the first lead 61 includes a die pad 611 and a terminal portion 612. The die pad 611 has a main surface 611A and a back surface 611B. The main surface 611A faces the side facing the electronic element 25 in the thickness direction z (the z1 side 1 in the thickness direction z). The main surface 611A is covered with a sealing resin 50. The back surface 611B faces the opposite side from the main surface 611A in the thickness direction z (the z2 side in the thickness direction z). The back surface 611B is exposed from the sealing resin 50. The back surface 611B is, for example, plated with tin (Sn).

[0143] The die pad 611 has a thick-walled portion that is relatively thick and a thin-walled portion that is relatively thin. Viewed in the thickness direction z, the thin-walled portion is located on one side of the first direction x compared to the thick-walled portion. The thin-walled portion is covered with sealing resin 50. Each of the thick-walled portion and the thin-walled portion includes a main surface 611A. The thick-walled portion includes a back surface 611B. The thin-walled portion is provided with a through hole 611C. The through hole 611C penetrates the thin-walled portion in the thickness direction z. The through hole 611C is circular in shape when viewed in the thickness direction z.

[0144] As shown in Figures 36 to 38, a stress buffer layer 31 is located between the main surface 611A (die pad 611) and the back electrode 251 (electronic element 25) in the thickness direction z. The stress buffer layer 31 is conductive. The stress buffer layer 31 is conductively bonded to the main surface 611A of the die pad 611 via the first bonding layer 35. The stress buffer layer 31 is also conductively bonded to the back electrode 221 of the electronic element 22 via the second bonding layer 36. As a result, the back electrode 251 of the electronic element 25 is electrically connected to the die pad 611 (first lead 61). The composition of the stress buffer layer 31 includes, for example, iron and nickel. The first bonding layer 35 and the second bonding layer 36 are, for example, solder. Alternatively, the first bonding layer 35 and the second bonding layer 36 may be sintered metal containing silver or the like, or a metallic bonding layer in which two metal layers in contact with each other are bonded by solid-phase diffusion. The thickness of the stress buffer layer 31 is thinner than the thickness of the die pad 611. The thickness of the first bonding layer 35 and the second bonding layer 36 are each thinner than the thickness of the stress buffer layer 31. The die pad 611 corresponds to the conductive portion of this disclosure.

[0145] As shown in Figures 39 and 40, the stress buffer layer 31 has a first surface 311 and a second surface 312. The first surface 311 and the second surface 312 are separated in the thickness direction z. The first surface 311 faces the z1 side in the thickness direction z, and the second surface 312 faces the z2 side in the thickness direction z. In the electronic device A30, the area of ​​the second surface 312 is larger than the area of ​​the second surface 25B of the electronic element 25. In the thickness direction z, the second surface 312 overlaps with the entire second surface 25B of the element. Also, the area of ​​the second surface 312 is larger than the area of ​​the first surface 311. In the thickness direction z, the second surface 312 overlaps with the entire first surface 311. The area of ​​the first surface 311 is larger than the area of ​​the second surface 25B of the element. Viewed in the thickness direction z, the first surface 311 overlaps with the entire second surface 25B of the element.

[0146] In electronic device A30, the coefficient of thermal expansion of the stress buffer layer 31 is smaller than that of the die pad 611. Furthermore, the coefficient of thermal expansion of the stress buffer layer 31 is smaller than that of the electronic element 25. The coefficient of thermal expansion of the die pad 611 (copper) is 17.7 × 10⁻⁶. -6 The temperature is / °C. The coefficient of linear expansion of electronic element 25 (silicon carbide) is 4.0 × 10⁻⁶.-6 The temperature is / °C. The coefficient of linear expansion of the stress buffer layer 31 is 3.0 × 10⁻⁶. -6 It is preferable that the temperature is below / °C. Examples of such stress buffering layers 31 include Invar, which is an alloy of iron and nickel.

[0147] The stress buffer layer 31 will be described in more detail with reference to Figures 39 and 40. The stress buffer layer 31 has a pair of first surfaces 313 and a pair of second surfaces 314. The pair of first surfaces 313 are located at one end in the first direction x and the other end in the first direction x. Each of the pair of first surfaces 313 has a first edge 313a and a second edge 313b. The first edge 313a connects to the first surface 311, and the second edge 313b connects to the second surface 312. Each of the first edge 313a and the second edge 313b extends in the second direction y.

[0148] On each first side surface 313, the line segment connecting the first edge 313a and the second edge 313b, viewed in the second direction y, is inclined with respect to the thickness direction z. On each first side surface 313, the second edge 313b is located further outward than the first edge 313a in the first direction x. The inclination angle α1 of the line segment connecting the first edge 313a and the second edge 313b with respect to the main surface 611A, viewed in the second direction y, is, for example, between 20 degrees and 90 degrees. In the electronic device A30, the pair of first side surfaces 313 are located closer to the z2 side of the thickness direction z as they move outward in the first direction x. Each first side surface 313 is a flat surface inclined with respect to the thickness direction z.

[0149] As shown in Figure 40, the pair of second sides 314 are located at one end in the second direction y and the other end in the second direction y. Each of the pair of second sides 314 has a third edge 314a and a fourth edge 314b. The third edge 314a connects to the first surface 311, and the fourth edge 314b connects to the second surface 312. Each of the third edge 314a and the fourth edge 314b extends in the first direction x.

[0150] On each second side surface 314, the line segment connecting the third edge 314a and the fourth edge 314b, viewed in the first direction x, is inclined with respect to the thickness direction z. On each second side surface 314, the fourth edge 314b is located further outward than the third edge 314a in the first direction x. The inclination angle α2 of the line segment connecting the third edge 314a and the fourth edge 314b with respect to the main surface 611A, viewed in the first direction x, is, for example, between 20 degrees and 90 degrees. In the electronic device A30, the pair of second side surfaces 314 are located closer to the z2 side of the thickness direction z as they move outward in the second direction y. Each second side surface 314 is a flat surface inclined with respect to the thickness direction z.

[0151] The terminal portion 612 includes a portion extending in the first direction x and is connected to the thickened portion of the die pad 611. As a result, the terminal portion 612 (first lead 61) is electrically connected to the back electrode 251 of the electronic element 25. Therefore, the terminal portion 612 (first lead 61) corresponds to the drain terminal of the electronic device A30. The terminal portion 612 is exposed from the sealing resin 50. The terminal portion 612 protrudes from the sealing resin 50 on the side opposite to the side where the die pad 611 is located in the first direction x.

[0152] The second lead 62 is located away from the die pad 611, as shown in Figures 35 and 36. The second lead 62 extends in the first direction x. The second lead 62 is conductive to the main surface electrode 252 of the electronic element 25. Therefore, the second lead 62 corresponds to the source terminal of the electronic device A30. The second lead 62 is located next to the terminal portion 612 in the second direction y.

[0153] As shown in Figures 35 and 36, the second lead 62 has a pad portion 621 and a terminal portion 622. The pad portion 621 is covered with a sealing resin 50. The terminal portion 622 is connected to the pad portion 621 and is exposed from the sealing resin 50. The terminal portion 622 protrudes from the sealing resin 50 on the side opposite to the side where the die pad 611 is located in the first direction x. The surface of the terminal portion 622 is, for example, tin-plated.

[0154] The third lead 63 is located away from the die pad 611, as shown in Figures 35 and 37. The third lead 63 extends in the first direction x. The third lead 63 is conductive to the gate electrode 253 of the electronic element 25. Therefore, the third lead 63 corresponds to the gate terminal of the electronic device A30. In the second direction y, the third lead 63 is located on the opposite side of the second lead 62 with respect to the terminal portion 612 of the first lead 61.

[0155] As shown in Figures 35 and 37, the third lead 63 has a pad portion 631 and a terminal portion 632. The pad portion 631 is covered with a sealing resin 50. The terminal portion 632 is connected to the pad portion 631 and is exposed from the sealing resin 50. The terminal portion 632 protrudes from the sealing resin 50 on the side opposite to the side where the die pad 611 is located in the first direction x. The surface of the terminal portion 632 is, for example, tin-plated.

[0156] As shown in Figures 35 and 36, the wire 47 is electrically bonded to the main surface electrode 252 of the electronic element 25 and to the pad portion 621 of the second lead 62. This allows the second lead 62 to be electrically connected to the main surface electrode 252. The wire 47 is composed of, for example, gold. Alternatively, the wire 47 may be composed of copper or aluminum. Instead of the wire 47, a conductive member made of a metal clip may be electrically bonded to the main surface electrode 252 and the pad portion 621. This conductive member may contain, for example, copper or a copper alloy.

[0157] As shown in Figures 35 and 37, the wire 48 is electrically connected to the gate electrode 253 of the electronic element 25 and to the pad portion 631 of the third lead 63. This ensures that the third lead 63 is electrically connected to the gate electrode 253. The composition of the wire 48 includes, for example, gold. Alternatively, the wire 48 may also contain copper or aluminum.

[0158] As shown in Figures 35 to 37, the sealing resin 50 covers the electronic element 25, the stress buffer layer 31, the wire 47, and the wire 48. As shown in Figures 36 to 38, the sealing resin 50 covers a portion of each of the first lead 61, the second lead 62, and the third lead 63. The sealing resin 50 is electrically insulating. The sealing resin 50 is made of a material including, for example, a black epoxy resin. The sealing resin 50 has a top surface 51, a bottom surface 52, a pair of first resin sides 53, a pair of second resin sides 54, and a pair of openings 55.

[0159] As shown in Figures 36 to 38, the top surface 51 faces the same side (thickness direction z1) as the main surface 611A of the die pad 611 in the thickness direction z. The bottom surface 52 faces the opposite side from the top surface 51 in the thickness direction z (the z2 side in the thickness direction z). The back surface 611B of the die pad 611 is exposed from the bottom surface 52.

[0160] As shown in Figures 34 and 36 to 38, the pair of first resin sides 53 are positioned apart from each other in a first direction x. Each of the pair of first resin sides 53 is connected to a top surface 51 and a bottom surface 52. From one of the pair of first resin sides 53, the terminal portion 612 of the first lead 61, the terminal portion 622 of the second lead 62, and the terminal portion 632 of the third lead 63 each protrude in the first direction x.

[0161] As shown in Figure 34, the pair of second resin sides 54 are located apart from each other in the second direction y. Each of the pair of second resin sides 54 is connected to the top surface 51 and the bottom surface 52. As shown in Figure 34, the pair of openings 55 are located apart from each other in the second direction y. Each of the pair of openings 55 is recessed inward into the sealing resin 50 from both the top surface 51 and one of the pair of second resin sides 54. A portion of the main surface 611A of the thin-walled portion of the die pad 611 is exposed from each of the pair of openings 55.

[0162] As shown in Figures 34 and 38, the sealing resin 50 is provided with mounting holes 56 that penetrate in the thickness direction z from the top surface 51 to the bottom surface 52. As shown in Figure 35, when viewed in the thickness direction z, the mounting holes 56 are surrounded by the through holes 611C of the die pad 611. That is, when viewed in the thickness direction z, the mounting holes 56 are contained within the through holes 611C.

[0163] Next, the operation of electronic device A30 will be explained.

[0164] The electronic device A30 includes a stress buffer layer 31 located between the main surface 611A of the die pad 611 (conductive portion) and the electronic element 25 in the thickness direction z. The area of ​​the second surface 312 of the stress buffer layer 31 facing the z2 side in the thickness direction z is larger than the area of ​​the second surface 25B of the electronic element 25 facing the z2 side in the thickness direction z. As a result, the bonding area of ​​the stress buffer layer 31 to the die pad 611 is larger than the bonding area of ​​the electronic element 25 to the stress buffer layer 31. Also, in the thickness direction z, the second surface 312 of the stress buffer layer 31 overlaps with the entire second surface 25B of the element. With this configuration including the stress buffer layer 31, the heat generated in the electronic element 25 can be efficiently dissipated to the die pad 611 via the stress buffer layer 31. As a result, the thermal stress acting on the electronic element 25 can be reduced in the electronic device A30.

[0165] The area of ​​the second surface 312 of the stress buffer layer 31 is larger than the area of ​​the first surface 311 facing the z1 side in the thickness direction z of the stress buffer layer 31. Viewed in the thickness direction z, the second surface 312 overlaps with the entire first surface 311. With this configuration, the heat transferred from the electronic element 25 to the stress buffer layer 31 can be more efficiently dissipated to the die pad 611. This is more preferable in reducing the thermal stress acting on the electronic element 25.

[0166] The stress buffer layer 31 has a first surface 313 located at the end of the first direction x, and a second surface 314 located at the end of the second direction y. The second edge 313b of the first surface 313 that connects to the second surface 312 is located further out in the first direction x than the first edge 313a of the first surface 313 that connects to the first surface 311. Looking in the second direction y, the inclination angle α1 of the line segment connecting the first edge 313a and the second edge 313b with respect to the main surface 611A is between 20 degrees and 90 degrees. The fourth edge 314b of the second surface 314 that connects to the second surface 312 is located further out in the second direction y than the third edge 314a of the second surface 314 that connects to the first surface 311. Looking in the first direction x, the inclination angle α2 of the line segment connecting the third edge 314a and the fourth edge 314b with respect to the main surface 611A is between 20 degrees and 90 degrees. This configuration makes it possible to reduce the thermal stress acting on the electronic element 25 while suppressing the area of ​​the second surface 312, which is the bottom surface of the stress buffer layer 31 (i.e., the size when viewed in the thickness direction z of the stress buffer layer 31) from becoming excessive.

[0167] In the electronic device A30, the coefficient of thermal expansion of the stress buffer layer 31 interposed between the die pad 611 (conductive portion) and the electronic element 25 is smaller than that of both the die pad 611 and the electronic element 25. With this configuration, the difference between the coefficient of thermal expansion of the electronic element 25 and the coefficient of thermal expansion of the stress buffer layer 31 can be made smaller than the difference between the coefficient of thermal expansion of the electronic element 25 and the coefficient of thermal expansion of the die pad 611. As a result, the thermal stress acting on the electronic element 25 can be reduced compared to the case where the electronic element 25 is directly bonded to the die pad 611.

[0168] The electronic device A30 includes a first bonding layer 35 that electrically bonds the die pad 611 (conductive portion) and the stress buffer layer 31, and a second bonding layer 36 that electrically bonds the stress buffer layer 31 and the electronic element 25. The thickness of the first bonding layer 35 and the second bonding layer 36 is thinner than the thickness of the stress buffer layer 31. With this configuration, the thermal resistance in the conductive path between the electronic element 25 and the die pad 611 can be reduced.

[0169] The electronic device relating to this disclosure is not limited to the embodiments described above. The specific configuration of each part of the electronic device relating to this disclosure can be modified in various ways.

[0170] In the above embodiments, the case in which the coefficient of thermal expansion of the stress buffer layer (31) is smaller than that of the conductive parts (111, 131, 611) and the electronic elements (21, 22, 23, 25) has been described, but the disclosure is not limited thereto. For example, the coefficient of thermal expansion of the stress buffer layer may be smaller than that of the conductive parts and larger than that of the electronic elements. The electronic elements of the disclosure are not limited to those exemplified in the above embodiments, and can be applied to various active and passive elements.

[0171] This disclosure includes the following appendix: Appendix 1. The device comprises: conductive portions (111, 131, 611) having main surfaces (111A, 131A, 611A) facing one side (z1 side) in the thickness direction (z); one or more electronic elements (21, 22, 23, 25) located on one side (z1 side) in the thickness direction (z) with respect to the main surfaces (111A, 131A, 611A); and a stress buffer layer (31) located in the thickness direction (z) between the main surfaces (111A, 131A, 611A) and at least one of the one or more (21, 22, 23, 25), wherein the stress buffer layer (31) has a first surface (311) facing one side (z1 side) in the thickness direction (z) and a second surface (312) facing the other side (z2 side) in the thickness direction (z). The electronic elements (21, 22, 23, 25) have a first surface (21A, 22A, 23A, 25A) facing one side (z1 side) in the thickness direction (z), and a second surface (21B, 22B, 23B, 25B) facing the other side (z2 side) in the thickness direction (z), the area of ​​the second surface (312) is larger than the area of ​​the second surface (21B, 22B, 23B, 25B), and when viewed in the thickness direction (z), the second surface (312) overlaps with the entirety of the second surface (21B, 22B, 23B, 25B), as shown in the electronic device (A10, A11, A12, A13, A14, A15, A16, A17, A20). Note 2. The area of ​​the second surface (312) is larger than the area of ​​the first surface (311) in the electronic device described in Appendix 1 (A10, A11, A12, A13, A14, A16, A17, A20). Appendix 3. The second surface (312) overlaps with the entire first surface (311) when viewed in the thickness direction (z) in the electronic device described in Appendix 2 (A10, A11, A12, A13, A14, A16, A17, A20).Note 4. The stress buffer layer (31) comprises a first surface (313) located at the end of a first direction (x) perpendicular to the thickness direction (z), the first surface (313) having a first edge (313a) connected to the first surface (311) and a second edge (313b) connected to the second surface (312), each of the first edge (313a) and the second edge (313b) extending in a second direction (y) perpendicular to the thickness direction (z) and the first direction (x), and the line segment connecting the first edge (313a) and the second edge (313b) in the second direction (y) is inclined with respect to the thickness direction (z), as described in Note 1 (A10, A11, A12, A13, A14, A15, A16, A17, A20). Note 5. The electronic device (A10, A11, A12, A13, A14, A16, A17, A20) described in Appendix 4, wherein the second edge (313b) is located outside the first edge (313a) in the first direction (x). Appendix 6. The electronic device (A10, A11, A12, A13, A14, A16, A17, A20) described in Appendix 5, wherein, viewed in the second direction (y), the inclination angle (α1) of the line segment connecting the first edge (313a) and the second edge (313b) with respect to the main surface (111A, 131A, 611A) is 20 degrees or more and 90 degrees or less. Appendix 7. The stress buffer layer (31) comprises a second surface (314) located at the end in the second direction (y), the second surface (314) having a third edge (314a) connected to the first surface (311) and a fourth edge (314b) connected to the second surface (312), each of the third edge (314a) and the fourth edge (314b) extending in the first direction (x), and the fourth edge (314b) located outward from the third edge (314a) in the second direction (y), as described in Appendix 5 or 6 (A10, A11, A12, A13, A14, A20). Appendix 8. In the first direction (x), the inclination angle (α2) of the line segment connecting the third edge (314a) and the fourth edge (314b) with respect to (111A, 131A, 611A) is 20 degrees or more and 90 degrees or less, as described in Appendix 7, for the electronic devices (A10, A11, A12, A13, A14, A20).Note 9. The electronic device (A10, A11, A12, A13, A20) described in Note 8, wherein the first side surface (313) is located on the other side (z2 side) of the thickness direction (z) as it moves outward in the first direction (x), and the second side surface (314) is located on the other side (z2 side) of the thickness direction (z) as it moves outward in the second direction (y). Note 10. The electronic device (A11, A13) described in any one of Notes 1 to 9, wherein the area of ​​the first surface (311) is the same as the area of ​​the second surface of the element (21B, 22B, 23B), and when viewed in the thickness direction (z), the first surface (311) overlaps with the entire second surface of the element (21B, 22B, 23B). Note 11. The area of ​​the first surface (311) is larger than the area of ​​the second surface of the element (21B, 22B, 23B, 25B), and when viewed in the thickness direction (z), the first surface (311) overlaps with the entirety of the second surface of the element (21B, 22B, 23B, 25B), as described in any of Appendix 1 to 9 (A10, A12, A14, A15, A16, A17, A20). Appendix 12. The thickness of the stress buffer layer (31) is thinner than the thickness of the conductive part (111, 131, 611), as described in any of Appendix 1 to 11 (A10, A11, A12, A13, A14, A15, A16, A17, A20). Appendix 13. The electronic device (A10, A11, A12, A13, A14, A15, A16, A17, A20) described in any of the appendices 1 to 12 further comprises: a first bonding layer (35) that electrically bonds the conductive parts (111, 131, 611) and the stress buffer layer (31); and a second bonding layer (36) that electrically bonds the stress buffer layer (31) and the electronic elements (21, 22, 23, 25), wherein the thickness of each of the first bonding layer (35) and the second bonding layer (36) is thinner than the thickness of the stress buffer layer (31). Appendix 14. The coefficient of linear expansion of the stress buffer layer (31) is smaller than that of the coefficient of linear expansion of the conductive parts (111, 131, 611) and the coefficient of linear expansion of the electronic elements (21, 22, 23, 25), as described in any of Appendix 1 to 13 of the electronic device (A10, A11, A12, A13, A14, A15, A16, A17, A20).Note 15. The composition of the stress buffer layer (31) is the electronic device (A10, A11, A12, A13, A14, A15, A16, A17, A20) described in Note 14, which includes iron and nickel. Note 16. The one or more electronic elements (21, 22, 23, 25) include switching elements (21, 22, 25), and the stress buffer layer (31) is located between the main surface (111A, 131A, 611A) and the switching elements (21, 22, 25), which is the electronic device (A10, A11, A12, A13, A14, A15, A16, A17, A20) described in any of Notes 1 to 15. Note 17. The one or more electronic elements (21, 22, 23, 25) includes a passive element (23), and the stress buffer layer (31) is located between the main surface (111A) and the passive element (23), and is an electronic device (A10, A11, A12, A13, A14, A15, A16, A17) as described in any of Appendix 1 to 16. Appendix 18. The electronic device (A10, A11, A12, A13, A14, A15, A16, A17) as described in any of Appendix 1 to 17, further comprising a support member (10) located on the opposite side of the one or more electronic elements (21, 22, 23) with respect to the conductive portion (111, 131) in the thickness direction (z), and the support member (10) includes an insulating layer (101).

[0172] A10-A17, A20, A30: Electronic device, 10: Support member, 101: Insulating layer, 102: Support layer, 103: Heat dissipation layer, 11: First conductive member, 111: Conductive part, 111A: Main surface, 112: First terminal, 112A: First mounting hole, 113: First support material, 12: Second conductive member, 121: Main material, 121A: Connection part, 121B: First connecting part, 121C: Second connecting part, 122: Second terminal, 122A: Second mounting hole, 13: Third conductive member, 131: Conductive part, 131A: Main surface, 132: Third terminal, 132A: Third mounting hole, 133: Second support material, 14 : Fourth conductive member, 15: First wiring, 151: First insulating layer, 152: First gate wiring, 153: First detection wiring, 154: First support layer, 16: Second wiring, 161: Second insulating layer, 162: Second gate wiring, 163: Second detection wiring, 164: Second support layer, 171: First gate terminal, 172: Second gate terminal, 181: First detection terminal, 182: Second detection terminal, 19: Dummy terminal, 21, 22: Electronic elements, 21A, 22A: First surface of element, 21B, 22B: Second surface of element, 211, 221: Back surface electrodes, 212, 222: Main surface electrodes, 213, 223 : Gate electrode, 23: Electronic element, 23A: First surface of element, 23B: Second surface of element, 231: First electrode, 232: Main second electrode, 223: Gate electrode, 24: Spacer, 25: Electronic element, 25A: First surface of element, 25B: Second surface of element, 251: Back surface electrode, 252: Main surface electrode, 253: Gate electrode, 29: Conductive junction layer, 31: Stress buffer layer, 311: First surface, 312: Second surface, 313: First side surface, 313a: First edge, 313b: Second edge, 314: Second side surface, 314a: Third edge, 314b: Fourth edge, 35: First junction layer, 36: Second junction layer , 41: First wire, 42: Second wire, 43: Third wire, 44: Fourth wire, 45: Fifth wire, 46: Sixth wire, 47, 48: Wires, 50: Sealing resin, 51: Top surface, 52: Bottom surface, 53: First resin side surface, 54: Second resin side surface, 55: Opening, 56: Mounting hole, 61: First lead, 611: Die pad (conductive part), 611A: Main surface, 611B: Back surface, 611C: Through hole, 612: Terminal part, 62: Second lead, 621: Pad part, 622: Terminal part, 63: Third lead, 631: Pad part, 632: Terminal part, α1, α2: Inclination angle

Claims

1. An electronic device comprising: a conductive portion having a main surface facing one side in the thickness direction; one or more electronic elements located on one side in the thickness direction with respect to the main surface; and a stress buffer layer located in the thickness direction between the main surface and at least one of the one or more electronic elements, wherein the stress buffer layer has a first surface facing one side in the thickness direction and a second surface facing the other side in the thickness direction; the electronic element has a first surface facing one side in the thickness direction and a second surface facing the other side in the thickness direction; the area of ​​the second surface is larger than the area of ​​the second surface; and, viewed in the thickness direction, the second surface overlaps with the entirety of the second surface.

2. The electronic device according to claim 1, wherein the area of ​​the second surface is larger than the area of ​​the first surface.

3. The electronic device according to claim 2, wherein, when viewed in the thickness direction, the second surface overlaps with the entirety of the first surface.

4. The electronic device according to claim 1, wherein the stress buffer layer has a first surface located at the end in a first direction perpendicular to the thickness direction, the first surface has a first edge connected to the first surface and a second edge connected to a second surface, each of the first edge and the second edge extends in a second direction perpendicular to the thickness direction and the first direction, and the line segment connecting the first edge and the second edge is inclined with respect to the thickness direction when viewed in the second direction.

5. The electronic device according to claim 4, wherein the second edge is located outward from the first edge in the first direction.

6. The electronic device according to claim 5, wherein, when viewed in the second direction, the angle of inclination of the line segment connecting the first edge and the second edge with respect to the main surface is 20 degrees or more and 90 degrees or less.

7. The electronic device according to claim 5 or 6, wherein the stress buffer layer comprises a second surface located at the end in the second direction, the second surface having a third edge connected to the first surface and a fourth edge connected to the second surface, each of the third and fourth edges extending in the first direction, and the fourth edge located outward from the third edge in the second direction.

8. The electronic device according to claim 7, wherein, when viewed in the first direction, the angle of inclination of the line segment connecting the third edge and the fourth edge with respect to the main surface is 20 degrees or more and 90 degrees or less.

9. The electronic device according to claim 8, wherein the first side surface is located on the other side in the thickness direction as it moves outward in the first direction, and the second side surface is located on the other side in the thickness direction as it moves outward in the second direction.

10. The electronic device according to any one of claims 1 to 9, wherein the area of ​​the first surface is the same as the area of ​​the second surface of the element, and when viewed in the thickness direction, the first surface overlaps with the entire second surface of the element.

11. The electronic device according to any one of claims 1 to 9, wherein the area of ​​the first surface is larger than the area of ​​the second surface of the element, and when viewed in the thickness direction, the first surface overlaps with the entire second surface of the element.

12. The electronic device according to any one of claims 1 to 11, wherein the thickness of the stress buffer layer is thinner than the thickness of the conductive part.

13. The electronic device according to any one of claims 1 to 12, further comprising: a first bonding layer for conductive bonding the conductive portion and the stress buffer layer; and a second bonding layer for conductive bonding the stress buffer layer and the electronic element, wherein the thickness of each of the first bonding layer and the second bonding layer is thinner than the thickness of the stress buffer layer.

14. The electronic device according to any one of claims 1 to 13, wherein the coefficient of linear expansion of the stress buffer layer is smaller than that of the coefficient of linear expansion of the conductive part and the coefficient of linear expansion of the electronic element.

15. The electronic device according to claim 14, wherein the composition of the stress buffer layer includes iron and nickel.

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