Semiconductor equipment

Abstract

This semiconductor device is configured so as to increase the energy that is able to be absorbed by an active clamp. This semiconductor device is provided with a semiconductor element, a sealing resin and a cover part. The semiconductor element comprises a first electrode. The sealing resin covers the semiconductor element. The cover part is arranged so as to intervene between the first electrode and the sealing resin. In addition, the cover part contains a material that has a higher thermal conductivity than the sealing resin.

Description

Technical Field

[0001] This disclosure relates to a semiconductor device.

Background Art

[0002] Switching elements are used for current control in various industrial equipment and automobiles. Patent Document 1 discloses an example of a conventional switching element. When a switching element cuts off current, energy is generated by the electromotive force that occurs. An active clamp is a function that absorbs this energy with the switching element.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In order to increase the speed and capacity of the switching operation, it is preferable to increase the energy that can be absorbed by the active clamp.

[0005] This disclosure was conceived under the above circumstances, and one of its problems is to provide a semiconductor device capable of increasing the energy that can be absorbed by an active clamp.

Means for Solving the Problems

[0006] The semiconductor device provided by this disclosure includes a semiconductor element having a first electrode, a sealing resin covering the semiconductor element, and a covering portion. The covering portion is interposed between the first electrode and the sealing resin and includes a material having a higher thermal conductivity than the sealing resin.

Effects of the Invention

[0007] According to the semiconductor device of this disclosure, the energy that can be absorbed by active clamping can be increased.

[0008] Other features and advantages of this disclosure will become more apparent from the detailed description below, with reference to the accompanying drawings. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a plan view showing a semiconductor device according to the first embodiment of this disclosure. [Figure 2] Figure 2 is a plan view of a main part of a semiconductor device according to the first embodiment of this disclosure. [Figure 3] Figure 3 is a circuit diagram showing semiconductor elements of a semiconductor device according to the first embodiment of this disclosure. [Figure 4] Figure 4 is a front view showing a semiconductor device according to the first embodiment of this disclosure. [Figure 5] Figure 5 is a side view showing a semiconductor device according to the first embodiment of this disclosure. [Figure 6] Figure 6 is a cross-sectional view along the VV line in Figure 2. [Figure 7] Figure 7 is a cross-sectional view along the line VI-VI in Figure 2. [Figure 8] Figure 8 is an enlarged cross-sectional view of a main part of a semiconductor device according to the first embodiment of this disclosure. [Figure 9] Figure 9 is an enlarged cross-sectional view of a main part of a semiconductor device according to the first embodiment of this disclosure. [Figure 10] Figure 10 is a plan view of a main part showing a first modified example of a semiconductor device according to the first embodiment of this disclosure. [Figure 11] Figure 11 is a plan view of a main part of a semiconductor device according to a second embodiment of the present disclosure. [Figure 12] Figure 12 is a plan view of a main part of a semiconductor device according to the third embodiment of this disclosure. [Figure 13] Figure 13 is a cross-sectional view along the line XIII-XIII in Figure 12. [Figure 14]FIG. 14 is a cross-sectional view taken along line XIV-XIV of FIG. 12. [Figure 15] FIG. 15 is a plan view of a main part showing a semiconductor device according to the fourth embodiment of the present disclosure. [Figure 16] FIG. 16 is a cross-sectional view taken along line XVI-XVI of FIG. 15. [Figure 17] FIG. 17 is a plan view of a main part showing a semiconductor device according to the fifth embodiment of the present disclosure. [Figure 18] FIG. 18 is a cross-sectional view taken along line XVIII-XVIII of FIG. 17. [Figure 19] FIG. 19 is a plan view of a main part showing a first modification of the semiconductor device according to the fifth embodiment of the present disclosure.

Embodiments for Carrying Out the Invention

[0010] Hereinafter, preferred embodiments of the present disclosure will be specifically described with reference to the drawings.

[0011] Terms such as "first", "second", "third", etc. in the present disclosure are used only for identification and are not intended to assign an order to those objects.

[0012] FIGS. 1 to 9 show a semiconductor device A1 according to the first embodiment of the present disclosure. The semiconductor device A1 of this embodiment includes a first lead 1, a plurality of second leads 2, a plurality of third leads 3, a semiconductor element 4, a plurality of first wires 51, a plurality of second wires 52, a plurality of metal blocks 6, a covering portion 7, and a sealing resin 8. The shape and size of the semiconductor device A1 are not particularly limited. As an example of the size of the semiconductor device A1, the size in the x direction is about 4 mm to 7 mm, the size in the y direction is about 4 mm to 8 mm, and the size in the z direction is about 0.7 mm to 2.0 mm.

[0013] Figure 1 is a plan view of semiconductor device A1. Figure 2 is a plan view of the main part of semiconductor device A1. Figure 4 is a front view of semiconductor device A1. Figure 5 is a side view of semiconductor device A1. Figure 6 is a cross-sectional view along line VI-VI in Figure 2. Figure 7 is a cross-sectional view along line VII-VII in Figure 2. Figure 8 is an enlarged cross-sectional view of the main part of semiconductor device A1. Figure 9 is an enlarged cross-sectional view of the main part of semiconductor device A1.

[0014] The first lead 1 is a component that supports the semiconductor element 4 and constitutes a conductive path to the semiconductor element 4. The material of the first lead 1 is not particularly limited and can be made of metals such as Cu, Ni, Fe, etc., and alloys thereof. The first lead 1 may also have a plating layer made of metals such as Ag, Ni, Pd, Au, etc., formed in appropriate places. The thickness of the first lead 1 is not particularly limited and can be, for example, about 0.12 mm to 0.2 mm.

[0015] The first lead 1 of this embodiment has a die pad portion 11 and two extension portions 12.

[0016] The die pad portion 11 is the part that supports the semiconductor element 4. The shape of the die pad portion 11 is not particularly limited, and in this embodiment, it is rectangular when viewed in the z direction. The die pad portion 11 has a die pad main surface 111 and a die pad back surface 112. The die pad main surface 111 is the surface facing the z direction. The die pad back surface 112 is the surface facing the opposite side from the die pad main surface 111 in the thickness direction. In the illustrated example, the die pad main surface 111 and the die pad back surface 112 are planar.

[0017] The two extensions 12 are portions that extend from the die pad portion 11 to both sides in the x-direction. In this embodiment, the extension 12 has a portion that extends from the die pad portion 11 along the x-direction, a portion that extends at an inclination in the z-direction toward the side where the die pad main surface 111 faces, and a portion that extends from that portion along the x-direction, and has a bent shape overall.

[0018] The multiple second leads 2 are separated from the first lead 1 and constitute a conduction path to the semiconductor element 4. In this embodiment, the multiple second leads 2 constitute a conduction path for the current switched by the semiconductor element 4. The multiple second leads 2 are arranged on one side in the y-direction relative to the first lead 1. Furthermore, the multiple second leads 2 are spaced apart from each other in the x-direction.

[0019] The material of the second lead 2 is not particularly limited and may consist of metals such as Cu, Ni, and Fe, or alloys thereof. Furthermore, the second lead 2 may have a plating layer made of metals such as Ag, Ni, Pd, and Au formed on it in appropriate locations. The thickness of the second lead 2 is not particularly limited and may be, for example, about 0.12 mm to 0.2 mm.

[0020] The second lead 2 of this embodiment has a pad portion 21 and a terminal portion 22.

[0021] The pad portion 21 is the part to which the first wire 51 is connected. In this embodiment, the pad portion 21 is located in the z-direction on the side where the die pad main surface 111 faces, compared to the die pad portion 11.

[0022] The terminal portion 22 is a strip-shaped part that extends outward in the y-direction from the pad portion 21. The terminal portion 22 has a bent shape when viewed in the x-direction, and its tip is in approximately the same position as the die pad portion 11 in the z-direction. In the illustrated example, the terminal portion 22 is a power terminal.

[0023] The multiple third leads 3 are separated from the first lead 1 and constitute a conduction path to the semiconductor element 4. In this embodiment, the multiple third leads 3 constitute a conduction path for control signal currents to control the semiconductor element 4. The multiple third leads 3 are located on the other side in the y-direction relative to the first lead 1. Furthermore, the multiple third leads 3 are spaced apart from each other in the x-direction.

[0024] The material of the third lead 3 is not particularly limited and may consist of metals such as Cu, Ni, and Fe, or alloys thereof. Furthermore, the third lead 3 may have a plating layer made of metals such as Ag, Ni, Pd, and Au formed on it in appropriate locations. The thickness of the third lead 3 is not particularly limited and may be, for example, about 0.12 mm to 0.2 mm.

[0025] The third lead 3 of this embodiment has a pad portion 31 and a terminal portion 32.

[0026] The pad portion 31 is the part to which the second wire 52 is connected. In this embodiment, the pad portion 31 is located in the z-direction on the side where the die pad main surface 111 faces, compared to the die pad portion 11.

[0027] The terminal portion 32 is a strip-shaped part that extends outward in the y-direction from the pad portion 31. The terminal portion 32 has a bent shape when viewed in the x-direction, and its tip is in the same (or approximately the same) position as the die pad portion 11 in the z-direction.

[0028] As shown in Figure 2, in this embodiment, the terminal portions 32 of the multiple third leads 3 are distinguished as terminal portions 321, 322, 323, and 324. Terminal portion 321 is an output terminal and is in conductivity with the third electrode 4031, which will be described later. Terminal portion 322 is a ground terminal and is in conductivity with the third electrode 4032, which will be described later. Terminal portion 323 is a self-diagnosis output terminal and is in conductivity with the third electrode 4033, which will be described later. Terminal portion 324 is an input terminal and is in conductivity with the third electrode 4034, which will be described later.

[0029] The semiconductor element 4 is an element that performs the electrical function of the semiconductor device A1. In this embodiment, the semiconductor element 4 performs a switching function. The semiconductor element 4 has an element body 40, a first electrode 401, a second electrode 402, and a plurality of third electrodes 403. The semiconductor element 4 also has a switching section 408 which is a part that constitutes a transistor that performs the switching function, and a control section 48 which controls, monitors, and protects the transistor of the switching section 408. The transistor included in the control section 48 is a lateral structure transistor.

[0030] The element body 40 has an element main surface 40a and an element back surface 40b. The element main surface 40a is the surface facing the same side as the die pad main surface 111 in the z direction. The element back surface 40b is the surface facing the opposite side from the element main surface 40a in the z direction. The material of the element body 40 is not particularly limited. Examples of materials for the element body 40 include semiconductor materials such as Si, SiC, and GaN.

[0031] The element body 40 has a switching section 408. The switching section 408 incorporates a transistor structure, such as a MOSFET (Metal Oxide Semiconductor Field Effect Transistor) or a MISFET (Metal Insulator Semiconductor Field Effect Transistor). As shown in Figures 1 and 2, the switching section 408 is arranged in the y-direction alongside the control section 48 when viewed in the z-direction. However, the specific arrangement of the switching section 408 and the control section 48 is not particularly limited.

[0032] The first electrode 401 is located on the main surface 40a of the element body 40. In the illustrated example, the first electrode 401 is located on the portion of the main surface 40a of the element on the side of the multiple second leads 2 in the y-direction. The first electrode 401 overlaps with the switching section 408 when viewed in the z-direction. In this embodiment, the first electrode 401 is located away from the control section 48 when viewed in the z-direction. In this embodiment, the first electrode 401 is the source electrode. The material of the first electrode 401 is not particularly limited and can be, for example, a metal such as Al (aluminum), Al-Si, or Cu (copper), or an alloy containing these. The first electrode 401 may also have a structure in which layers made of multiple materials selected from these metals are laminated.

[0033] Furthermore, as shown in Figures 8 and 9, the first electrode 401 of this embodiment has a base thickness portion 4011, a thinning portion 4012, and a raised portion 4013. The base thickness portion 4011 is the portion of the first electrode 401 that occupies most of the area where the bonding portion 511 of the first wire 51 and the metal block 6, which will be described later, are not located. The thickness of the base thickness portion 4011 is, for example, the thickness at the time when the plating or other processing for forming the first electrode 401 is completed.

[0034] The thinned portion 4012 is the part of the first electrode 401 where either the bonding portion 511 or the metal block 6 is joined, and is thinner than the base thickness portion 4011. The thinned portion 4012 is, for example, the part that has been thinned by the joining process of the bonding portion 511 and the metal block 6.

[0035] The raised portion 4013 is located between the base thickness portion 4011 and the thinning portion 4012. The raised portion 4013 surrounds the thinning portion 4012 in an annular shape. The raised portion 4013 is thicker than both the base thickness portion 4011 and the thinning portion 4012.

[0036] The second electrode 402 is located on the back surface 40b of the element body 40. When viewed in the z direction, the second electrode 402 overlaps with the switching unit 408 and the control unit 48, and in this embodiment, it covers the entire back surface 40b of the element. In this embodiment, the second electrode 402 is the drain electrode. The material of the second electrode 402 is not particularly limited and can be a metal such as Al (aluminum), Al-Si, or Cu (copper), or an alloy containing these. Alternatively, the second electrode 402 may have a structure in which layers made of multiple materials selected from these metals are laminated.

[0037] The specific configuration of the control unit 48 is not particularly limited. The control unit 48 may include, for example, a current sensor circuit, a temperature sensor circuit, an overcurrent protection circuit, an overheating protection circuit, an undervoltage malfunction prevention circuit, and so on.

[0038] Multiple third electrodes 403 are arranged on the main surface 40a of the element. In the illustrated example, the multiple third electrodes 403 are arranged on the portion of the main surface 40a of the element on the side of the multiple third leads 3 in the y direction. When viewed in the z direction, the multiple third electrodes 403 overlap with the control unit 48. In this embodiment, the multiple third electrodes 403 are mainly conductive to the control unit 48. The number of multiple third electrodes 403 is not particularly limited. The number of third electrodes 403 may be one. In the illustrated example, the semiconductor element 4 has four third electrodes 403.

[0039] In the illustrated example, the four third electrodes 403 include third electrodes 4031, 4032, 4033, and 4034. Third electrode 4031 is an output electrode, and when the load is short-circuited and a current exceeding the overcurrent detection value flows, the output current is limited. Third electrode 4032 is a ground electrode. Third electrode 4033 is a self-diagnostic output electrode, and its potential differs depending on whether or not there is an overcurrent or overheating condition. Third electrode 4034 is an input electrode, and a pull-down resistor is connected internally.

[0040] Figure 3 shows an example of the circuit configuration of the switching unit 408 and the control unit 48. The switching unit includes a transistor. The control unit 48 includes an energy absorption circuit 481 and a protection circuit 482. The energy absorption circuit 481 is a circuit that absorbs electrical energy caused by transient voltages, etc., and includes, for example, a Zener diode and a resistor. The protection circuit 482 is a circuit that protects the control unit 48, and includes, for example, an overheating protection unit 4821 and an overcurrent protection unit 4822.

[0041] Multiple first wires 51 connect the first electrode 401 of the semiconductor element 4 to multiple second leads 2. The material of the first wires 51 is not particularly limited and can be a metal such as Au, Cu, or Al. The first wires 51 may contain a metal different from the metal contained in the first electrode 401. The first wires 51 have bonding portions 511, bonding portions 512, and loop portions 513. The specific configuration of the first wires 51 is not particularly limited. In the illustrated example, the first wires 51 are made of a material containing Cu and are formed, for example, by a capillary. In this embodiment, a current switched by the semiconductor element 4 flows through the multiple first wires 51.

[0042] The semiconductor device according to this disclosure is not limited to a configuration in which the first wire 51 is joined to the first electrode 401. For example, a conductive member made of a metal plate material other than the first wire 51 may be joined to the first electrode 401. Alternatively, the semiconductor device may include other electrodes that conduct to the first electrode 401 via a conductive path formed within the semiconductor element 4, and a conductive member including the first wire 51 may be in contact with these electrodes.

[0043] The bonding portion 511 is electrically connected to the first electrode 401 of the semiconductor element 4 and is positioned to overlap with the first electrode 401 when viewed in the z direction. In this embodiment, the bonding portion 511 is bonded to the first electrode 401 and is a so-called first bonding portion.

[0044] As shown in Figure 8, the bonding portion 511 has a first surface 5111 and a second surface 5112. The first surface 5111 and the second surface 5112 are aligned in the z direction, with the maximum diameter portion of the bonding portion 511 (the portion where the dimensions are maximum in directions perpendicular to the z direction, such as the x and y directions, and the portion that intersects with the dashed line shown in Figure 8) in between.

[0045] The first surface 5111 is inclined such that as it moves away from the first electrode 401 in the z direction, it moves away from the center of the bonding portion 511 in directions perpendicular to the z direction, such as the x and y directions. In the illustrated example, the first surface 5111 is a convex surface. The second surface 5112 is located on the opposite side of the first surface 5111, with the maximum diameter portion in between, and in the illustrated example, it is a convex surface.

[0046] The bonding portion 512 is the part that is joined to the pad portion 21 of the second lead 2. The bonding portion 512 is what is known as the second bonding portion.

[0047] The loop portion 513 is connected to the bonding portion 511 and the bonding portion 512, and is, for example, a curved portion overall.

[0048] In the illustrated example, the multiple bonding portions 511 are arranged along the outer edge of the first electrode 401. More specifically, they are arranged along three sides included in the outer edge of the element body 40. Furthermore, the bonding portions 511 are arranged in a single line along the outer edge of the first electrode 401.

[0049] Multiple second wires 52 connect the third electrode 403 of the semiconductor element 4 to the multiple third leads 3. The material of the second wires 52 is not particularly limited and can be a metal such as Au, Cu, or Al. The second wires 52 have bonding portions 521, 522, and loop portions 523. The specific configuration of the second wires 52 is not particularly limited. In the illustrated example, the second wires 52 are formed by, for example, a capillary. In this embodiment, control signal currents for controlling the semiconductor element 4 flow through the multiple second wires 52. In the example shown in Figure 2, the third electrode 4031 and the pad portion 31 of the third lead 3 having a terminal portion 321 are connected by the second wires 52. Also, the third electrode 4032 and the pad portion 31 of the third lead 3 having a terminal portion 322 are connected by the second wires 52. Furthermore, the third electrode 4033 and the pad portion 31 of the third lead 3 having a terminal portion 323 are connected by the second wire 52. Also, the third electrode 4034 and the pad portion 31 of the third lead 3 having a terminal portion 324 are connected by the second wire 52.

[0050] The bonding portion 521 is bonded to the second electrode 402 of the semiconductor element 4. The bonding portion 521 is the so-called first bonding portion.

[0051] The bonding portion 522 is the part that is joined to the pad portion 31 of the third lead 3. The bonding portion 522 is what is known as the second bonding portion.

[0052] The loop portion 523 is connected to the bonding portion 521 and the bonding portion 522, and is, for example, a curved portion overall.

[0053] Multiple metal blocks 6 each contain metal and are bonded to the first electrode 401. The specific configuration of the metal blocks 6 is not particularly limited. In this embodiment, the metal blocks 6 have a configuration similar to that of the bonding portion 511 of the first wire 51. That is, they are formed by cutting the wire material after performing the bonding portion 511 formation process in the method of forming the first wire 51 using a capillary. The metal blocks 6 in this embodiment contain Cu. The number of metal blocks 6 is not particularly limited and may be one. Furthermore, the semiconductor device of this disclosure may have a configuration without metal blocks 6.

[0054] The arrangement of the multiple metal blocks 6 is not particularly limited. In the illustrated example, the multiple metal blocks 6 are arranged inward relative to the bonding portion 511, on the side opposite to the outer edge of the first electrode 401. The multiple metal blocks 6 are also arranged in a matrix. Examples of the matrix arrangement of the multiple metal blocks 6 include arrangements in which multiple rows intersect along two directions, the x and y directions, and so-called staggered arrangements.

[0055] As shown in Figure 9, the metal block 6 has a first surface 61, a second surface 62, and a projection 63. The first surface 61 and the second surface 62 are aligned in the z direction, flanking the largest diameter portion of the metal block 6 (the portion where the dimensions are largest in directions perpendicular to the z direction, such as the x and y directions, and where it intersects with the dashed line shown in Figure 8).

[0056] The first surface 61 is inclined such that as it moves away from the first electrode 401 in the z direction, it moves away from the center of the metal mass 6 in directions perpendicular to the z direction, such as the x and y directions. In the illustrated example, the first surface 61 is a convex surface. The second surface 62 is located on the opposite side of the first surface 61, with the maximum diameter portion in between, and in the illustrated example, it is a convex surface.

[0057] The projection 63 is a portion that protrudes from the second surface 62 in the z-direction on the side opposite to the first electrode 401. In this example, the projection 63 is the portion where the wire material for forming the metal block 6 has been cut.

[0058] The coating portion 7 is interposed between the first electrode 401 and the sealing resin 8. The coating portion 7 contains a material with a higher thermal conductivity than the sealing resin 8. The material of the coating portion 7 is not particularly limited, and if the sealing resin 8 is made of an insulating resin, the coating portion 7 contains a metal. The coating portion 7 may contain a metal different from the metal contained in the first electrode 401. Examples of metals constituting the coating portion 7 include Ag or Cu. The coating portion 7 also contains sintered Ag or sintered Cu. For example, if the coating portion 7 contains sintered Ag, it is preferable to use a type of sintered Ag that can be formed without pressure. If the coating portion 7 is made of unpressurized sintered Ag, it can be formed, for example, by discharging a material paste that will become sintered Ag from a nozzle, applying the material paste, and then appropriately heating the material paste.

[0059] The coating portion 7 is not limited to a metal-containing structure, and may, for example, contain a resin with a higher thermal conductivity than the insulating resin constituting the sealing resin 8. When the sealing resin 8 is made of epoxy resin, examples of resins constituting the coating portion 7 include PC (polycarbonate), PA6 (nylon 6), PPS (polyphenylene sulfide), and PBT (polybutylene terephthalate). Furthermore, the coating portion 7 may have a structure in which fillers to increase thermal conductivity are mixed into these resins.

[0060] In this example, the coating portion 7 contains sintered Ag and is in contact with both the first electrode 401 and the sealing resin 8. Furthermore, when viewed in the z-direction, the coating portion 7 is positioned inward from the outer edge of the first electrode 401.

[0061] In this example, the covering portion 7 is in contact with at least one of the multiple metal blocks 6. Furthermore, the covering portion 7 is in contact with at least one of the bonding portions 511 of the multiple first wires 51. Also, in the illustrated example, the covering portion 7 covers a large portion of the multiple metal blocks 6. Also, in the illustrated example, the covering portion 7 covers a large portion of the bonding portions 511 of the multiple first wires 51. As shown in Figure 2, the covering portion 7 is positioned in the region surrounded by the bonding portions 511 of the multiple first wires 51.

[0062] As shown in Figures 6 and 7, the maximum thickness of the coating portion 7 is greater than the thickness of the bonding portion 511 of the first wire 51. When viewed along the z-direction, the thickness of the coating portion 7 is greater in the center than in the outer periphery. The maximum thickness of the coating portion is preferably 20 μm or more, more preferably 80 μm or more, and even more preferably 160 μm or more. The thickness of the coating portion 7 may have a distribution that includes, for example, two portions having a maximum value spaced apart from each other in the y-direction, and a portion having a minimum value located between these two portions.

[0063] As shown in Figure 8, in the illustrated example, the covering portion 7 includes a portion located between the first electrode 401 (raised portion 4013) and the first surface 5111 of the bonding portion 511. In other words, the covering portion 7 has a portion that wraps around below the maximum diameter portion of the bonding portion 511.

[0064] Furthermore, as shown in Figure 9, in the illustrated example, the covering portion 7 has a portion located between the first electrode 401 (raised portion 4013) and the first surface 61 of the metal mass 6. In other words, the covering portion 7 has a portion that wraps around below the maximum diameter portion of the first surface 61.

[0065] The sealing resin 8 covers the first lead 1, a portion of each of the multiple second leads 2 and the multiple third leads 3, the semiconductor element 4, a portion of the multiple first wires 51, a portion of the multiple second wires 52, a portion of the multiple metal blocks 6, and the covering portion 7. The sealing resin 8 is made of an insulating resin and includes, for example, an epoxy resin mixed with a filler.

[0066] The shape of the sealing resin 8 is not particularly limited. In the illustrated example, the sealing resin 8 has a main resin surface 81, a resin back surface 82, two first resin side surfaces 83, and two second resin side surfaces 84.

[0067] The resin main surface 81 faces the same side as the die pad main surface 111 in the z direction and is, for example, a flat surface. The resin back surface 82 is a surface that faces the opposite side from the resin main surface 81 in the z direction and is, for example, a flat surface.

[0068] The two first resin side surfaces 83 are located between the resin main surface 81 and the resin back surface 82 in the z direction and face both sides in the x direction. The two second resin side surfaces 84 are located between the resin main surface 81 and the resin back surface 82 in the z direction and face both sides in the y direction.

[0069] Next, we will explain the operation of semiconductor device A1.

[0070] When the semiconductor element 4 is operating, at least a portion of the energy generated by the electromotive force due to the interruption of current is converted into heat. If this heat remains in the semiconductor element 4, the temperature of the semiconductor element 4 will become excessively high. The semiconductor device A1 includes a covering portion 7 interposed between the first electrode 401 and the sealing resin 8. The covering portion 7 contains a material with a higher thermal conductivity than the sealing resin 8. Therefore, heat transfer from the first electrode 401 to the covering portion 7 is promoted, making it possible to suppress an excessive temperature rise in the semiconductor element 4. Thus, the semiconductor device A1 can increase the amount of energy that can be absorbed by active clamping.

[0071] If the coating portion 7 contains metal, heat transfer from the first electrode 401 can be further enhanced. If Ag or Cu is selected as the metal contained in the coating portion 7, the thermal conductivity of the coating portion 7 can be further increased. If the coating portion 7 contains sintered Ag or sintered Cu, the coating portion 7 of the desired shape can be more reliably formed by applying a material paste and sintering this material paste.

[0072] If the coating portion 7 contains metal, the coating portion 7 constitutes a conductive member in contact with the first electrode 401. This makes it possible to form a conductive path from a certain part of the switching portion 408 to one of the first wires 51 by the coating portion 7 in addition to the first electrode 401. Therefore, the resistance of the semiconductor element 4 can be reduced.

[0073] When the covering portion 7 comes into contact with the bonding portion 511 of the first wire 51, a heat transfer path is formed between the covering portion 7 and the first wire 51, allowing heat to be transferred between them. Therefore, for example, the heat transferred to the covering portion 7 can be dissipated to the second lead 2 via the first wire 51.

[0074] Furthermore, if the first electrode 401 contains Al and the coating portion 7 contains sintered Ag, the bonding strength between the first electrode 401 and the coating portion 7 may be insufficient. However, if the first wire 51 contains Cu, the bonding strength between the first electrode 401 and the first wire 51, as well as the bonding strength between the first wire 51 and the coating portion 7, are both higher than the bonding strength between the first electrode 401 and the coating portion 7. This makes it possible to suppress the coating portion 7 from peeling off from the first electrode 401.

[0075] As shown in Figure 8, in this embodiment, the coating portion 7 includes a portion located between the first electrode 401 (raised portion 4013) and the first surface 5111 of the bonding portion 511. In other words, the coating portion 7 has a portion that wraps around below the maximum diameter portion of the bonding portion 511. This further suppresses peeling of the coating portion 7.

[0076] The semiconductor device A1 comprises multiple metal blocks 6. The thermal conductivity of the metal blocks 6 is higher than that of the sealing resin 8. This allows for a further increase in the energy that can be absorbed by the active clamp.

[0077] Furthermore, when the first electrode 401 contains Al and the coating portion 7 contains sintered Ag, the bonding strength between the first electrode 401 and the coating portion 7 may be insufficient. However, when the metal ingot 6 contains Cu, the bonding strength between the first electrode 401 and the metal ingot 6, as well as the bonding strength between the metal ingot 6 and the coating portion 7, are both higher than the bonding strength between the first electrode 401 and the coating portion 7. This makes it possible to suppress the peeling of the coating portion 7 from the first electrode 401.

[0078] As shown in Figure 9, in this embodiment, the coating portion 7 includes a portion located between the first electrode 401 (raised portion 4013) and the first surface 61 of the metal mass 6. In other words, the coating portion 7 has a portion that wraps around below the maximum diameter portion of the first surface 61. This further suppresses peeling of the coating portion 7.

[0079] In this embodiment, the bonding portions 511 of the multiple first wires 51 are arranged along the outer edge of the first electrode 401. The multiple metal blocks 6 are arranged inside the multiple bonding portions 511. This prevents interference between the nozzle for applying the material paste and the first wires 51 when forming the coating portion 7 after forming the multiple first wires 51 and the multiple metal blocks 6. It also prevents the material paste of the coating portion 7 from unintentionally adhering to the first wires 51.

[0080] Figures 10 to 19 show modified examples and other embodiments of the present disclosure. In these figures, elements identical or similar to those in the above embodiments are denoted by the same reference numerals.

[0081] Figure 10 shows a first modified example of semiconductor device A1. In this modified example, semiconductor device A11 differs from semiconductor device A1 in that the area where the covering portion 7 is provided is different.

[0082] In this example, the covering portion 7 is not in contact with the bonding portion 511 of the multiple first wires 51, and is separated from the bonding portion 511 of the multiple first wires 51 when viewed in the z direction. That is, the bonding portion 511 is covered by the sealing resin 8, not the covering portion 7. Also, similar to semiconductor device A1, the covering portion 7 covers most of the multiple metal blocks 6.

[0083] This modified configuration also increases the energy that can be absorbed by the active clamp. Furthermore, as can be seen from this embodiment, the covering portion 7 is not limited to a configuration that contacts the first wire 51, but may be configured to contact the first electrode 401.

[0084] Figure 11 shows a semiconductor device according to a second embodiment of the present disclosure. The semiconductor device A2 of this embodiment differs from the embodiment described above in that it does not include a plurality of metal blocks 6.

[0085] In this embodiment, the metal block 6 is not bonded to the first electrode 401, but the bonding portions 511 of the multiple first wires 51 are bonded to it. The contact area between the covering portion 7 and the first electrode 401 is larger than the contact area of ​​the semiconductor device A1. The covering portion 7 may or may not be in contact with the bonding portions 511 of the multiple first wires 51.

[0086] This embodiment also allows for an increase in the energy that can be absorbed by the active clamp. Furthermore, as can be seen from this embodiment, the semiconductor device according to this disclosure may not have a configuration that includes a plurality of metal blocks 6.

[0087] Figures 12 to 14 show a semiconductor device according to a third embodiment of the present disclosure. The semiconductor device A3 of this embodiment differs from the embodiment described above in the relationship between the first electrode 401, the plurality of first wires 51, the plurality of 6, and the covering portion 7.

[0088] In this embodiment, a coating portion 7 is interposed between the bonding portions 511 of the multiple first wires 51 and the multiple metal blocks 6 and the first electrode 401. That is, the bonding portions 511 of the multiple first wires 51 and the multiple metal blocks 6 are formed on the coating portion 7 and are not in contact with the first electrode 401. The multiple first wires 51 and the multiple metal blocks 6 are electrically connected to the first electrode 401 via the coating portion 7.

[0089] In this embodiment, for example, after forming a coating portion 7 on the first electrode 401, bonding of multiple first wires 51 and formation of multiple metal blocks 6 can be performed.

[0090] This embodiment also increases the energy that can be absorbed by the active clamp. Furthermore, as can be seen from this embodiment, the covering portion 7 is not limited to a configuration that covers the bonding portion 511 and the metal block 6, but may be configured in which the bonding portion 511 and the metal block 6 are formed on the covering portion 7.

[0091] The configurations of the multiple bonding portions 511, multiple metal blocks 6, and covering portions 7 in semiconductor devices A1, A11, A2, and A3 can be arbitrarily combined and adopted as appropriate in the following embodiments.

[0092] Figures 15 and 16 show a semiconductor device according to a fourth embodiment of the present disclosure. The semiconductor device A4 of this embodiment differs from the embodiments described above mainly in the configuration of the semiconductor element 4 and in the inclusion of a semiconductor element 42 and a plurality of third wires 53.

[0093] The semiconductor element 4 of this embodiment has the switching unit 408 in the above-described embodiment and performs the switching function, but does not have the control unit 48 in the above-described embodiment.

[0094] The semiconductor element 42 performs functions such as controlling, monitoring, and protecting the semiconductor element 4. Both the semiconductor element 4 and the semiconductor element 42 are mounted on the die pad main surface 111 of the die pad portion 11 via a bonding material 49. In the illustrated example, the semiconductor element 4 and the semiconductor element 42 are arranged side by side in the y direction.

[0095] The semiconductor element 42 has a plurality of electrodes 421 and a plurality of electrodes 422. Both the plurality of electrodes 421 and the plurality of electrodes 422 are located on the same side in the z direction. In the illustrated example, the plurality of electrodes 421 are located on the side where the semiconductor element 4 is located in the y direction. The plurality of electrodes 422 are located on the side where the plurality of third leads 3 are located in the y direction. The plurality of electrodes 422 includes electrodes 4221, 4222, 4223, and 4224. Electrode 4221 corresponds to the third electrode 4031 in the semiconductor device A1 described above. Electrode 4222 corresponds to the third electrode 4032 in the semiconductor device A1 described above. Electrode 4223 corresponds to the third electrode 4033 in the semiconductor device A1 described above. Electrode 4224 corresponds to the third electrode 4034 in the semiconductor device A1 described above.

[0096] In this embodiment, the multiple second wires 52 are individually connected to the multiple electrodes 422 and the multiple third leads 3 of the semiconductor element 42. The bonding portion 521 is joined to the electrode 422. The bonding portion 522 is joined to the pad portion 31 of the third lead 3.

[0097] The semiconductor device A4 comprises a plurality of third wires 53. The plurality of third wires 53 are individually connected to a plurality of third electrodes 403 of the semiconductor element 4 and a plurality of electrodes 421 of the semiconductor element 42. The third wire 53 has, for example, a bonding portion 531, a bonding portion 532, and a loop portion 533, and has a configuration similar to that of, for example, the second wire 52. The bonding portion 531 is bonded to the third electrode 403. The bonding portion 532 is bonded to the electrode 421.

[0098] This embodiment also allows for an increase in the energy absorbable by the active clamp. Furthermore, as can be understood from this embodiment, the specific configuration of the semiconductor element 4 is not particularly limited. The die pad portion 11 may be equipped not only with the semiconductor element 4, but also with other semiconductor elements such as semiconductor element 42 in addition to semiconductor element 4. Moreover, the functions of semiconductor elements other than semiconductor element 4 are not particularly limited.

[0099] Figures 17 and 18 show a semiconductor device according to a fifth embodiment of the present disclosure. The semiconductor device A5 of this embodiment includes semiconductor element 4 and semiconductor element 42, similar to semiconductor device A4.

[0100] In this embodiment, the semiconductor element 42 is mounted on the main element surface 40a of the semiconductor element 4. That is, the semiconductor element 42 is positioned on the opposite side of the die pad portion 11 from the semiconductor element 4 in the z direction. The semiconductor element 4 and the semiconductor element 42 are stacked on top of each other.

[0101] The semiconductor element 42 is bonded to the main surface 40a of the semiconductor element 4, for example, by a bonding material 49. In the illustrated example, the semiconductor element 42 is mounted at a position away from the first electrode 401 in the y-direction when viewed in the z-direction. However, unlike the illustrated example, the semiconductor element 42 may be placed on the first electrode 401.

[0102] In the illustrated example, both the first electrode 401 and the semiconductor element 42 are elongated rectangles with the x-direction as their longitudinal direction. The multiple third electrodes 403 are located between the first electrode 401 and the semiconductor element 42 in the y-direction and are arranged in a line in the x-direction.

[0103] This embodiment also allows for an increase in the energy that can be absorbed by the active clamp. Furthermore, as can be seen from this embodiment, the arrangement and mounting configuration of the semiconductor element 42 are not particularly limited.

[0104] Figure 19 shows a first modified example of semiconductor device A5. The semiconductor device A51 of this modified example differs from the semiconductor device A5 described above mainly in the specific configuration of semiconductor elements 4 and 42. Figure 19 shows the main part of semiconductor device A51, showing the region including semiconductor elements 4 and 42 and a part of the die pad portion 11, with the sealing resin 8 omitted. Note that semiconductor device A51 may appropriately include the above-mentioned plurality of second leads 2 and plurality of third leads 3, etc.

[0105] In this example as well, the semiconductor element 42 is mounted on the main surface 40a of the semiconductor element 4. The semiconductor element 42 is arranged in the x-direction with respect to the first electrode 401.

[0106] In this example, the multiple first wires 51 are formed, for example, by a wedge bonding technique. The bonding portion 511 has a shape that extends long in the y-direction. The multiple bonding portions 511 are arranged side by side in the x-direction.

[0107] The semiconductor element 42 has a long rectangular shape with the y-direction as its longitudinal direction. The multiple third electrodes 403 of the semiconductor element 4 are located on one side of the semiconductor element 42 in the y-direction and are arranged in a line in the x-direction.

[0108] This embodiment also allows for an increase in the energy that can be absorbed by the active clamp. Furthermore, as can be seen from this embodiment, the arrangement and mounting configuration of the semiconductor element 42 are not particularly limited.

[0109] The semiconductor device relating to this disclosure is not limited to the embodiments described above. The specific configuration of each part of the semiconductor device relating to this disclosure can be modified in various ways. This disclosure includes the embodiments described in the following appendix.

[0110] Note 1. A semiconductor device having a first electrode, A sealing resin covering the semiconductor element, It comprises a covering part, The covering portion is interposed between the first electrode and the sealing resin and includes a material with a higher thermal conductivity than the sealing resin, wherein the covering portion is a semiconductor device. Note 2. The aforementioned covering portion is a semiconductor device as described in Appendix 1, which includes metal. Note 3. The aforementioned coating portion comprises Ag or Cu, as described in Appendix 2, for the semiconductor device. Note 4. The semiconductor device described in Appendix 3, wherein the coating portion includes sintered Ag or sintered Cu. Note 5. The first electrode is a semiconductor device according to any one of the appendices 1 to 4, comprising Al. Note 6. The semiconductor device according to any one of appendices 1 to 5, further comprising at least one first wire having a bonding portion joined to the first electrode. Note 7. The at least one first wire includes a plurality of first wires, The semiconductor device according to Appendix 6, wherein the bonding portion of each of the plurality of first wires is arranged along the outer edge of the first electrode. Note 8. The semiconductor device according to Appendix 7, wherein the covering portion is located in the region surrounded by the bonding portion of each of the plurality of first wires. Note 9. The semiconductor device according to any one of appendices 6 to 8, wherein each first wire contains a metal different from the metal contained in the first electrode. Note 10. Each first wire is a semiconductor device according to any one of appendices 6 to 9, comprising Cu. Note 11. The covering portion is in contact with the bonding portion of each first wire, as described in any of appendices 6 to 10, for the semiconductor device. Note 12. A semiconductor device according to any one of appendices 6 to 11, further comprising at least one metal block bonded to the first electrode. Note 13. The semiconductor device according to Appendix 12, wherein the metal mass contains a metal different from the metal contained in the first electrode. Note 14. The covering portion is in contact with the metal mass, and is a semiconductor device as described in Appendix 12 or 13. Note 15. The covering portion covers the metal mass, as described in Appendix 14, for the semiconductor device. Note 16. The semiconductor device according to Appendix 15, wherein the maximum thickness of the covering portion is greater than the thickness of the bonding portion of each first wire. Note 17. The semiconductor device according to appendix 15 or 16, wherein the covering portion has an outer peripheral portion and a central portion that is thicker than the outer peripheral portion. Note 18. The semiconductor device according to any one of appendices 15 to 17, wherein the maximum thickness of the coating portion is 20 μm or more. Note 19. The semiconductor device according to any one of appendices 15 to 17, wherein the maximum thickness of the coating portion is 80 μm or more. Note 20. The semiconductor device according to any one of appendices 15 to 17, wherein the maximum thickness of the coating portion is 160 μm or more. Note 21. The semiconductor device according to any one of appendices 15 to 20, wherein the metal block is positioned on the opposite side of the outer edge of the first electrode relative to the bonding portion of each first wire. Note 22. Each first wire has a loop portion connected to the bonding portion, The semiconductor device according to Appendix 21, wherein the loop portion intersects with the outer edge of the first electrode in a plan view and extends to the outside of the semiconductor element. Note 23. The metal mass has a first surface that faces the first electrode and is inclined such that it moves away from the center of the metal mass as it moves away from the first electrode. The semiconductor device according to any one of appendices 15 to 22, wherein the covering portion has a portion located between the first electrode and the first surface. Note 24. The semiconductor element comprises a switching unit having a switching function and a control unit that controls the switching unit. The semiconductor device according to any one of appendices 1 to 23, wherein the first electrode is the electrode of the switching section. Note 25. The first electrode is a source electrode, as described in Appendix 24, for the semiconductor device. [Explanation of Symbols]

[0111] A1, A11, A2, A3, A4, A5, A51: Semiconductor equipment 1: First lead 2: Second lead 3: Third lead 4: Semiconductor element 6: Metal block 7: Coating 8: Sealing resin 11: Die pad portion 12: Extension portion 21: Pad section 22: Terminal section 31: Pad section 32: Terminal section 40: Element body 40a: Main surface of the element 40b: Back surface of the element 42: Semiconductor element 48: Control unit 49: Joining material 51: First wire 52: Second wire 53: Third wire 61: First face 62: Second face 63: Protrusion 81: Main resin surface 82: Back surface of resin 83: First resin side 84: Second resin side 111: Main surface of die pad 112: Back surface of die pad 401: 1st electrode 402: 2nd electrode 403,4031,4032,4033,4034: 3rd electrode 408: Switching section 421,422,4221,4222,4223,4224: Electrode 511, 512, 521, 522, 531, 532: Bonding section 513, 523, 533: Loop section 4011: Base thickness section 4012: Thinner area 4013: Elevated area 5111: 1st side 5112: 2nd side

Claims

1. A semiconductor device having a first electrode, A sealing resin covering the semiconductor element, It comprises a covering part, The covering portion is interposed between the first electrode and the sealing resin and includes a material with a higher thermal conductivity than the sealing resin. The present invention further comprises at least one first wire having a bonding portion joined to the first electrode, The at least one first wire includes a plurality of first wires, A semiconductor device in which the bonding portion of each of the plurality of first wires is arranged along the outer edge of the first electrode.

2. The semiconductor device according to claim 1, wherein the coating portion includes a metal.

3. The semiconductor device according to claim 2, wherein the coating portion comprises Ag or Cu.

4. The semiconductor device according to claim 3, wherein the coating portion comprises sintered Ag or sintered Cu.

5. The semiconductor device according to claim 1, wherein the first electrode contains Al.

6. The semiconductor device according to claim 1, wherein the covering portion is located in the region surrounded by the bonding portion of each of the plurality of first wires.

7. The semiconductor device according to claim 1, wherein each first wire contains a metal different from the metal contained in the first electrode.

8. Each first wire comprises Cu, according to claim 1, the semiconductor device.

9. The semiconductor device according to claim 1, wherein the covering portion is in contact with the bonding portion of each first wire.

10. The semiconductor device according to claim 1, further comprising at least one metal block bonded to the first electrode.

11. The semiconductor device according to claim 10, wherein the metal mass comprises a metal different from the metal contained in the first electrode.

12. The semiconductor device according to claim 10, wherein the covering portion is in contact with the metal block.

13. The semiconductor device according to claim 12, wherein the covering portion covers the metal block.

14. The semiconductor device according to claim 13, wherein the maximum thickness of the covering portion is greater than the thickness of the bonding portion of each first wire.

15. The semiconductor device according to claim 13, wherein the covering portion has an outer peripheral portion and a central portion that is thicker than the outer peripheral portion.

16. The semiconductor device according to claim 13, wherein the maximum thickness of the coating portion is 20 μm or more.

17. The semiconductor device according to claim 13, wherein the maximum thickness of the coating portion is 80 μm or more.

18. The semiconductor device according to claim 13, wherein the maximum thickness of the coating portion is 160 μm or more.

19. The semiconductor device according to any one of claims 13 to 18, wherein the metal block is positioned on the opposite side of the outer edge of the first electrode from the bonding portion of each first wire.

20. Each first wire has a loop portion connected to the bonding portion, The semiconductor device according to claim 19, wherein the loop portion intersects with the outer edge of the first electrode in a plan view and extends to the outside of the semiconductor element.

21. The metal mass has a first surface that faces the first electrode and is inclined such that it moves away from the center of the metal mass as it moves away from the first electrode. The semiconductor device according to claim 13, wherein the covering portion has a portion located between the first electrode and the first surface.

22. The semiconductor element comprises a switching unit having a switching function and a control unit that controls the switching unit. The semiconductor device according to claim 1, wherein the first electrode is the electrode of the switching unit.

23. The semiconductor device according to claim 22, wherein the first electrode is a source electrode.

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