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

Abstract

To provide a semiconductor device with improved reliability and a power converter using the semiconductor device.SOLUTION: A semiconductor device 1 has a semiconductor element 2, a first heat-dissipating substrate 4, a second heat-dissipating substrate 5, and a heat-dissipating block 6. The semiconductor element 2 has an electrode 3. The semiconductor element 2 is mounted on the first heat-dissipating substrate 4. The heat-dissipating block 6 is positioned opposite the electrode 3. The second heat-dissipating substrate 5 is disposed opposite the electrode 3 as seen from the heat-dissipating block 6. A bonding material 13 covers the side of the heat-dissipating block 6 and is in contact with the electrode 3 of the semiconductor element 2 and the second heat-dissipating substrate 5.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] In recent years, with the movement toward realizing a carbon-free society, semiconductor devices, such as power semiconductor devices, are being used not only for home appliance applications such as air conditioners, but also for in-vehicle applications such as electric vehicles and hybrid vehicles, and even for railway applications (see, for example, JP 2013-239486 A and JP 2020-188163 A). In JP 2013-239486 A, to ensure bonding strength, a terminal having a through hole and an electrode of a semiconductor element are bonded with a bonding material via a heat dissipation member. In JP 2020-188163 A, a conductor plate and a semiconductor element are bonded via a conductor spacer, and the conductor plate is bonded to a portion of the conductor spacer with solder, and are electrically connected within the semiconductor device. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-239486 [Patent Document 2] Japanese Patent Publication No. 2020-188163 Summary of the Invention [Problem to be solved by the invention]

[0004] However, because the semiconductor devices described above are used in a wide range of products, they are increasingly used in high-load environments (for example, high-temperature environments or vibration environments), and the durability of the semiconductor devices is required. Thus, further improvements in the reliability, typified by durability, of conventional semiconductor devices are required.

[0005] The present disclosure has been made to solve the above-mentioned problems, and an object of the present disclosure is to provide a semiconductor device with improved reliability and a power conversion device using the semiconductor device. [Means for solving the problem]

[0006] A semiconductor device according to the present disclosure includes a semiconductor element, a first heat dissipation substrate, a second heat dissipation substrate, and a heat dissipation block. The semiconductor element has electrodes. The semiconductor element is mounted on the first heat dissipation substrate. The heat dissipation block is disposed to face the electrodes. The second heat dissipation substrate is disposed on the opposite side of the heat dissipation block from the electrodes. A bonding material covers the side of the heat dissipation block and is in contact with the electrodes of the semiconductor element and the second heat dissipation substrate.

[0007] A power conversion device according to the present disclosure includes a main conversion circuit, a drive circuit, and a control circuit. The main conversion circuit has the semiconductor device described above and converts and outputs input power. The drive circuit outputs a drive signal to the semiconductor device for driving the semiconductor device. The control circuit outputs a control signal to the drive circuit for controlling the drive circuit.

[0008] A method for manufacturing a semiconductor device according to the present disclosure includes a preparing step, a mounting step, a bonding step of the semiconductor element, a mounting step of a second heat dissipation substrate, and a bonding step of the second heat dissipation substrate. In the preparing step, a semiconductor element having a first heat dissipation substrate and electrodes is prepared. In the mounting step, the semiconductor element is mounted on the first heat dissipation substrate via a first bonding material. In the bonding step, the semiconductor element is bonded to the first heat dissipation substrate via the first bonding material by heating the first bonding material. In the mounting step, a heat dissipation block is mounted on the electrodes of the semiconductor element via a second bonding material, and the second heat dissipation substrate is further mounted on the heat dissipation block via a third bonding material. In the bonding step, the second and third bonding materials are heated so that the second and third bonding materials cover the side surfaces of the heat dissipation block and bond the electrodes of the semiconductor element to the second heat dissipation substrate. [Effects of the Invention]

[0009] According to the above, it is possible to obtain a semiconductor device with improved reliability and a power conversion device using the semiconductor device. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a cross-sectional view of a semiconductor device according to a first embodiment. [Figure 2] FIG. 2 is a partially enlarged cross-sectional view of region II in FIG. [Figure 3] FIG. 10 is a partially enlarged cross-sectional view showing a modification of the semiconductor device according to the first embodiment. [Figure 4] FIG. 10 is a partially enlarged cross-sectional view showing a modification of the semiconductor device according to the first embodiment. [Figure 5] 3 is a flowchart of a method for manufacturing a semiconductor device according to the first embodiment. [Figure 6] FIG. 10 is a partially enlarged cross-sectional view of a semiconductor device before the bonding material is melted in a modified example of the method for manufacturing the semiconductor device according to the first embodiment. [Figure 7] FIG. 10 is a partially enlarged cross-sectional view of a semiconductor device after melting of the bonding material in a modified example of the method for manufacturing the semiconductor device according to the first embodiment. [Figure 8] FIG. 10 is a cross-sectional view of a semiconductor device according to a second embodiment. [Figure 9] FIG. 10 is a cross-sectional view showing a modified example of the semiconductor device according to the second embodiment. [Figure 10] FIG. 11 is a partially enlarged cross-sectional view of a semiconductor device according to a third embodiment before the bonding material is melted. [Figure 11] FIG. 11 is a partially enlarged cross-sectional view of the semiconductor device according to the third embodiment after the bonding material has melted. [Figure 12] FIG. 11 is a partially enlarged cross-sectional view showing a modified example of the semiconductor device according to the third embodiment. [Figure 13] FIG. 10 is a partially enlarged cross-sectional view of a semiconductor device according to a fourth embodiment. [Figure 14] FIG. 10 is a partially enlarged cross-sectional view showing a modified example of the semiconductor device according to the fourth embodiment. [Figure 15] FIG. 11 is a partially enlarged cross-sectional view of a semiconductor device according to a fifth embodiment. [Figure 16] FIG. 11 is a partially enlarged cross-sectional view showing a modified example of the semiconductor device according to the fifth embodiment. [Figure 17] FIG. 11 is a partially enlarged cross-sectional view showing a modification of the semiconductor device according to the fifth embodiment. [Figure 18] FIG. 11 is a partially enlarged cross-sectional view showing a modified example of the semiconductor device according to the fifth embodiment. [Figure 19] FIG. 13 is a block diagram showing a configuration of a power conversion system to which a power conversion device according to a sixth embodiment is applied. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments of the present disclosure will be described. Unless otherwise specified, the same or corresponding parts in the following drawings will be denoted by the same reference numerals, and the description thereof will not be repeated.

[0012] Embodiment 1 <Configuration of semiconductor device> Fig. 1 is a cross-sectional view of a semiconductor device 1 according to embodiment 1. Fig. 2 is a partially enlarged cross-sectional view of the semiconductor device 1 in region II of Fig. 1.

[0013] The semiconductor device 1 shown in FIGS. 1 and 2 is, for example, a power semiconductor device and mainly includes a semiconductor element 2, a first heat dissipation substrate 4, a second heat dissipation substrate 5, a heat dissipation block 6, terminals 7a, 7b, and 7c, metal wires 14, an insulating heat dissipation sheet 15, and a sealing resin 16. As shown in FIG. 2, the semiconductor element 2 has electrodes 3. As shown in FIG. 1, the semiconductor element 2 is mounted on the surface (top surface) of the first heat dissipation substrate 4 via bonding portions 13c. The semiconductor element 2 has electrodes 3 on the surface (top surface) opposite the surface (bottom surface) facing the first heat dissipation substrate 4. The second heat dissipation substrate 5 is disposed on the opposite side of the first heat dissipation substrate 4 from the semiconductor element 2. The second heat dissipation substrate 5 is connected to the electrodes 3 of the semiconductor element 2 via bonding portions 13a formed by bonding material 13. First through holes 8a are formed in the terminals 7a and 7b. The terminal 7a is disposed between the electrode 3 of the semiconductor element 2 and the second heat dissipation substrate 5. The heat dissipation block 6 is disposed inside the first through hole 8a of the terminal 7a. The electrode 3 of the semiconductor element 2 and the second heat dissipation substrate 5 are connected to the terminal 7a by a joint 13a. The joint 13a fills the inside of the first through hole 8a of the terminal 7a so as to cover the outer periphery of the heat dissipation block 6. In other words, the electrode 3 of the semiconductor element 2 and the second heat dissipation substrate 5 are connected by the joint 13a to the region of the terminal 7a where the first through hole 8a is formed.

[0014] The first heat dissipation substrate 4 is connected to the terminal 7b by a bonding portion 13b formed by a bonding material 13. The heat dissipation block 6 is placed inside the first through hole 8a of the terminal 7b. The bonding portion 13b fills the inside of the first through hole 8a of the terminal 7b so as to cover the outer periphery of the heat dissipation block 6. The first heat dissipation substrate 4 is connected by the bonding portion 13b to the area of ​​the terminal 7b where the first through hole 8a is formed. The terminal 7c is connected to, for example, the electrode 3 which is the control electrode of the semiconductor element 2 via a metal wire wiring 14. The first heat dissipation substrate 4 and the second heat dissipation substrate 5 are connected to an insulating heat dissipation sheet 15 on each of their surfaces (bottom surfaces or outer peripheral surfaces) opposite to the surfaces facing each other.

[0015] As shown in FIG. 1, two semiconductor elements 2 are mounted on the surface of the first heat dissipation substrate 4. Each of the two semiconductor elements 2 includes an electrode 3 (see FIG. 2). The electrodes 3 of the two semiconductor elements 2 are connected to the second heat dissipation substrate 5 and a terminal 7a via a bonding portion 13a. That is, a first through-hole 8a is formed in the terminal 7a in a region located above the semiconductor element 2. In the semiconductor device 1 shown in FIG. 1, two first through-holes 8a are formed in the terminal 7a. The terminal 7a extends from above the two semiconductor elements 2 to the outside of the sealing resin 16. The terminal 7b is connected to the outer periphery on the top surface of the first heat dissipation substrate 4 via a bonding portion 13b. In the cross-sectional view shown in FIG. 1, the terminal 7c extends in the same direction as the terminal 7a.

[0016] The semiconductor element 2, the first heat dissipation substrate 4, the second heat dissipation substrate 5, a portion of the terminal 7a, a portion of the terminal 7b, and a portion of the terminal 7c are covered with a sealing resin 16. A portion of each of the terminals 7a, 7b, and 7c extends outward from the surface of the sealing resin 16 so that they can be connected to an external device outside the sealing resin 16. The portions of the terminals 7a, 7b, and 7c extending outward from the sealing resin 16 may be bent, for example, by forming. Electrical conductors (not shown), such as wiring or terminals, are connected to the portions of the terminals 7a, 7b, and 7c for electrical connection to a circuit board or another semiconductor device. Any method can be used to connect the electrical conductors to the above-mentioned portions, but the electrical conductors and the above-mentioned portions may also be fixed by a fixing member such as a screw.

[0017] As shown in FIG. 1, the circuit configuration of the semiconductor device 1 is a so-called 2-in-1 type in which two semiconductor elements 2 are mounted on one module. The circuit configuration of the semiconductor device 1 represents, for example, the upper arm or lower arm of an inverter circuit. The circuit configuration of the semiconductor device 1 does not necessarily have to be a 2-in-1 type. For example, the circuit configuration may be a 1-in-1 type or a 6-in-1 type.

[0018] The semiconductor element 2 is a so-called power semiconductor element 2 that controls power. The number of semiconductor elements 2 mounted on the semiconductor device 1 is at least one. Note that multiple semiconductor elements 2 may be mounted depending on the specifications of the semiconductor device 1. Furthermore, materials such as silicon carbide (SiC), gallium nitride (GaN), gallium oxide (Ga2O3), or diamond may be used as the semiconductor element 2. Such wide-bandgap semiconductor materials, which have a wider bandgap than silicon, can be used as the substrate of the semiconductor element 2. Using a wide-bandgap semiconductor material as the substrate can provide a semiconductor device 1 that is highly efficient and can withstand high temperatures. In particular, when the bonding material 13 constituting the bonding portion 13a is a sintered material made of silver (Ag) or the like, the heat resistance of the bonding portion 13a is improved. In this case, a power semiconductor element 2 made of silicon carbide, which can operate at high temperatures, can be preferably used. As a result, a semiconductor device 1 that can operate at higher temperatures than a semiconductor element based on silicon can be realized.

[0019] The type of semiconductor element 2 is not particularly limited, but examples include an IGBT (Insulated Gate Bipolar Transistor), a MOSFET (Metal Oxide Semiconductor Field Effect Transistor), and a Schottky barrier diode. Furthermore, for example, the semiconductor element 2 may be a RC-IGBT (Reverse Conducting IGBT) in which an IGBT and a freewheeling diode are integrated on a single semiconductor chip. The length of one side of the semiconductor element 2 is, for example, 1.5 mm or more and 15 mm or less.

[0020] As shown in FIG. 1, the first heat dissipation substrate 4 and the second heat dissipation substrate 5 are connected to an insulating heat dissipation sheet 15 on their respective surfaces (bottom surfaces or outer peripheral surfaces) opposite the surfaces facing each other. The first heat dissipation substrate 4, the second heat dissipation substrate 5, and the heat dissipation block 6 may each be made of a material with high thermal conductivity. For example, the first heat dissipation substrate 4, the second heat dissipation substrate 5, and the heat dissipation block 6 may be made of a metal material such as copper (Cu), aluminum (Al), or a copper-molybdenum (CuMo) alloy. The first heat dissipation substrate 4, the second heat dissipation substrate 5, and the heat dissipation block 6 may also be made of a composite material such as a silicon carbide-aluminum composite (AlSiC) or a silicon carbide-magnesium composite (MgSiC).

[0021] The insulating heat-dissipating sheet 15 includes an insulating layer 15a and a metal layer 15b. The insulating layer 15a is connected to the bottom surfaces of the first heat-dissipating substrate 4 and the second heat-dissipating substrate 5 (the surfaces opposite the surfaces where the first heat-dissipating substrate 4 and the second heat-dissipating substrate 5 face each other). The metal layer 15b is connected to the surface of the insulating layer 15a opposite the surface connected to the first heat-dissipating substrate 4 and the second heat-dissipating substrate 5. The insulating heat-dissipating sheet 15 has a laminated structure (two-layer structure) in which the insulating layer 15a and the metal layer 15b are stacked. The surface of the metal layer 15b opposite the surface connected to the insulating layer 15a is exposed from the sealing resin 16. Note that the insulating heat-dissipating sheet 15 does not have to have a two-layer structure. That is, the insulating heat-dissipating sheet 15 may include the insulating layer 15a and multiple other metal layers 15b. For example, the insulating heat-dissipating sheet 15 may have two or more metal layers 15b stacked.

[0022] The thermal conductivity of the insulating heat dissipation sheet 15 is, for example, 2 W / (m·K) or more and 18 W / (m·K) or less. The thickness of the insulating heat dissipation sheet 15 is, for example, 0.1 mm or more and 0.2 mm or less. The insulating layer 15a may be made of, for example, a resin containing a filler. The filler may be, for example, a filler containing any of alumina (Al2O3), aluminum nitride (AlN), silicon nitride (Si3N4), silicon dioxide (SiO2), or boron nitride (BN). The insulating layer 15a may be made of a resin filled with such a filler. The resin may be, for example, an epoxy resin. The material constituting the metal layer 15b includes a metal with excellent thermal conductivity. The metal may be, for example, copper (Cu) or aluminum (Al).

[0023] As shown in FIGS. 1 and 2 , a first through hole 8a is provided in the terminal 7a. The first through hole 8a is filled with a bonding material 13, and a bonding portion 13a is formed to connect the terminal 7a to the electrode 3 of the semiconductor element 2 and the second heat dissipation substrate 5. The terminal 7a has a first terminal main surface 10a facing the electrode 3 of the semiconductor element 2 and a second terminal main surface 10b on the opposite side of the first terminal main surface 10a. The bonding portion 13a is formed so that the interface between the bonding portion 13a and the terminal 7a extends not only to the inner side surface of the first through hole 8a but also to the first terminal main surface 10a and the second terminal main surface 10b of the terminal 7a. A bonding portion 13b is formed in the same manner as the terminal 7a so that the terminal 7b is connected to the first heat dissipation substrate 4. The interface between the joint 13b and the terminal 7b is formed so that it extends not only to the inner side surface of the first through hole 8a but also to the first terminal main surface 10a and the second terminal main surface 10b of the terminal 7b. The first through hole 8a is formed by a chemical processing method such as etching or a physical processing method such as machining.

[0024] The material forming the terminals 7a, 7b, and 7c is, for example, copper (Cu). Note that the material forming the terminals 7a, 7b, and 7c may be any material that has heat dissipation properties in addition to electrical conductivity. For example, the material forming the terminals 7a, 7b, and 7c may be an alloy containing either copper (Cu) or aluminum (Al), or a composite material in which these metals are laminated.

[0025] The thickness of the terminals 7a, 7b, and 7c is, for example, 0.3 mm or more and 1.2 mm or less. The terminals 7a, 7b, and 7c form an integrated lead frame until tie bar cutting or lead cutting is performed in the manufacturing process described below. The thickness of each of the terminals 7a, 7b, and 7c in the direction A shown in FIG. 1 and the width of each of the terminals 7a, 7b, and 7c in the direction perpendicular to the plane of FIG. 1 may be appropriately changed depending on the current capacity flowing through the terminals 7a, 7b, and 7c. For example, the current capacity flowing through the metal wire interconnection 14 connected to the electrode 3, which is the control electrode of the semiconductor element 2, is relatively smaller than the current capacity flowing through the terminals 7a and 7b. Therefore, the thickness and width of the terminal 7c may be smaller than those of the terminals 7a and 7b. This allows the semiconductor device 1 to be miniaturized. Furthermore, the current capacity required for the semiconductor device 1 has been increasing in recent years. For example, the rated current of the semiconductor device 1 may exceed 1,000 A. In such a case, the thickness of the terminals 7a and 7b may exceed the above-mentioned 1.2 mm.

[0026] The material constituting the metal wire wiring 14 is, for example, a metal containing any one selected from the group consisting of aluminum (Al), copper (Cu), silver (Ag), and gold (Au). The metal wire wiring 14 may also be a metal made of an alloy selected from the above group. The metal wire wiring 14 is bonded to the terminal 7c and the electrode 3, which is the control electrode of the semiconductor element 2, by applying pressure and ultrasonic vibration. The metal wire wiring 14 is a wiring that carries current to control the semiconductor element 2. Therefore, the current capacity required for the metal wire wiring 14 is relatively small. This allows the bonding area between the metal wire wiring 14 and the electrode 3, which is the control electrode of the semiconductor element 2, and the terminal 7c to be small. Therefore, the diameter of the metal wire wiring 14 is, for example, 0.02 mm or more and 0.2 mm or less.

[0027] The main component of the sealing resin 16 is, for example, a thermosetting resin. Examples of suitable thermosetting resins include epoxy resin. The material constituting the sealing resin 16 may be a resin that, in addition to being thermosetting, has elasticity, adhesion, heat resistance, and insulating properties appropriate for the external size and internal structure of the semiconductor device 1. For example, in addition to epoxy resin, silicone resin, phenolic resin, polyimide resin, and the like may be used as the material. Furthermore, to ensure the strength and thermal conductivity of the semiconductor device 1, the sealing resin 16 may contain dispersed fine particles or fillers. The fine particles and fillers may be made of, for example, inorganic ceramic materials. Examples of inorganic ceramic materials include alumina (Al2O3), aluminum nitride (AlN), silicon nitride (Si3N4), silicon dioxide (SiO2), boron nitride (BN), diamond, silicon carbide (SiC), and boron oxide (BO3). By including fine particles or filler in the sealing resin 16, it is possible to improve the heat dissipation from the semiconductor element 2 that generates heat to the outside of the semiconductor device 1.

[0028] 1 and 2, the semiconductor device 1 according to the first embodiment is characterized in that the electrodes 3 and terminals 7a of the semiconductor element 2, and the second heat dissipation substrate 5 are bonded to each other with a bonding material 13 around the heat dissipation block 6. Specifically, as shown in FIG. 2, the periphery of the heat dissipation block 6 is composed of a first heat dissipation block main surface 6a facing the electrodes 3 of the semiconductor element 2, a second heat dissipation block main surface 6b opposite the first heat dissipation block main surface 6a, and a heat dissipation block side surface 6c connecting the first heat dissipation block main surface 6a and the second heat dissipation block main surface 6b. Bonding portions 13a that bond the electrodes 3 and terminals 7a of the semiconductor element 2, and the second heat dissipation substrate 5 are formed so as to cover the periphery of the heat dissipation block 6 with the bonding material 13. By providing bonding portions 13a that cover the periphery of the heat dissipation block 6 in this manner, the durability of bonding portions 13a can be improved. For example, without the heat dissipation block 6, if a crack occurs in the joint 13a due to stress or strain during operation of the power semiconductor device, the joint 13a is brittle and the crack propagates quickly, resulting in a high probability of disconnection during operation of the power semiconductor device. On the other hand, if the heat dissipation block 6 is provided inside the joint 13a, even if a crack occurs in the joint 13a, the heat dissipation block 6, which is stronger than the joint 13a, prevents the crack from propagating, significantly reducing the possibility of disconnection during operation of the semiconductor device 1. Furthermore, because the heat dissipation block 6 is bonded with the bonding material 13 so as to cover the entire periphery, not just a portion of the periphery, the strength of the joint 13a is increased by the amount of the bonding material 13. As a result, a highly reliable semiconductor device 1 can be obtained.

[0029] When a portion of the outer periphery of the heat dissipation block 6 is in contact with the electrode 3 of the semiconductor element 2, the side surface of the first through hole 8a, or the second heat dissipation substrate 5, the remaining portion may be covered with the bonding material 13. For example, as a modified example of the manufacturing method of the semiconductor device 1 described later, when the heat dissipation block 6 is mounted on the electrode 3 without the bonding material 13 and the bonding material 13 arranged on the heat dissipation block 6 is heated, as shown in FIG. 7 , the first heat dissipation block main surface 6a is directly connected to the electrode 3, and a bonding portion 13a is formed such that the second heat dissipation block main surface 6b and the heat dissipation block side surface 6c are covered with the bonding material 13. Alternatively, as shown in FIG. 12 , the first heat dissipation block main surface 6a is directly connected to the electrode 3 of the semiconductor element 2, and a portion of the heat dissipation block side surface 6c is directly connected to the side surface of the first through hole 8a of the terminal 7a, and the bonding portion 13a is formed such that the portion of the heat dissipation block side surface 6c that is not directly connected to the side surface of the first through hole 8a and the second heat dissipation block main surface 6b are covered with the bonding material 13. Alternatively, the second heat dissipation substrate 5 and the main surface 6b of the second heat dissipation block 6 may be in direct contact with each other. That is, only the electrodes 3 of the semiconductor element 2, the second heat dissipation substrate 5, the terminals 7a, and the bonding material 13 may be directly connected to the outer periphery of the heat dissipation block 6.

[0030] 3, the corners 6d of the heat dissipation block 6 may be rounded or chamfered. During operation of the power semiconductor device, high stress and strain occur at the joints 13a near the corners 6d of the heat dissipation block 6, making them prone to cracking. Therefore, by rounding or chamfering the corners 6d of the heat dissipation block 6, the stress and strain occurring at the corners 6d can be reduced, and as a result, cracking at the joints 13a can be suppressed.

[0031] The material constituting the bonding material 13 used in the semiconductor device 1 may be, for example, any one selected from the group consisting of solder, sintered material, and adhesive. When solder, a conductive metal containing tin (Sn), is used as the bonding material 13, it is preferable that, when the solder is melted, the solder sufficiently wets and spreads not only on the side surface of the first through hole 8a but also to the area adjacent to the first through hole 8a on the first terminal main surface 10a and the second terminal main surface 10b of the terminal 7. In this case, the bonding area at the interface between the bonding material 13 and the terminal 7 can be increased, thereby ensuring bonding strength at the interface. For example, as shown in FIG. 2, the bonding portion 13a bonding the terminal 7a to the semiconductor element 2 can be shaped like a rivet. In this case, the interface between the bonding portion 13a and the terminal 7a is formed so as to extend not only on the side surface of the first through hole 8a but also to the first terminal main surface 10a and the second terminal main surface 10b of the terminal 7a. That is, the portions of the first terminal main surface 10a and the second terminal main surface 10b of the terminal 7a adjacent to the first through-hole 8a are covered with a part of the joint 13a. The surface of the portion of the joint 13a that extends onto the first terminal main surface 10a or the second terminal main surface 10b of the terminal 7a is curved. This curved surface may be recessed toward the heat dissipation block 6, for example.

[0032] The semiconductor element 2 generates heat during operation of the semiconductor device 1. Therefore, the bonding portion 13a of the bonding material 13 may be a sintered material containing metal particles containing silver (Ag) or copper (Cu), which have excellent heat dissipation properties. When the bonding portion 13a is a sintered material, the first through hole 8a of the terminal 7 opens to the second terminal main surface 10b, which is the upper surface. Therefore, the solvent contained in the sintered material is sufficiently volatilized during the heating process of the sintered material that will become the bonding portion 13a disposed inside the first through hole 8a. This effect can be reliably removed from the sintered material that will become the bonding portion 13a. This effect can also be achieved in the bonding portion 13b disposed in the first through hole 8a of the terminal 7b. Examples of the solvent include an organic coating provided on the surface of the metal particles to prevent the metal particles from agglomerating, and a solvent mixed with the metal particles to turn the sintered material into a paste.

[0033] Here, if a large amount of solvent remains in the bonding portion 13a after the heating process of the sintered material that will become the bonding portion 13a, voids due to the solvent will occur in the bonding portion 13a. As a result, the first through-hole 8a is not filled with the bonding material 13, and the strength of the bonding portion 13a and the bonding portion 13b will be insufficient. Furthermore, if large voids are formed in the bonding portion 13a and the bonding portion 13b, the reliability, lifespan, and thermal conductivity of the bonding portion 13a and the bonding portion 13b will decrease. On the other hand, in the semiconductor device 1 according to the present embodiment, when a sintered material is used as the bonding material 13, the first through-hole 8a penetrates the terminal 7 (the first through-hole 8a is open), so the solvent in the sintered material is sufficiently removed from the bonding portion 13a and the bonding portion 13b during the heating process. This prevents the above-mentioned problems from occurring.

[0034] If the bonding portions 13a and 13b formed by the bonding material 13 do not require a high thermal conductivity of, for example, 100 W / (m·K) or more, a resin-containing sintered material or adhesive may be used as the bonding material 13. When the bonding material 13 is a resin-containing sintered material or adhesive, the resin reduces the elasticity of the bonding portions 13a and 13b. As a result, the bonding portions 13a and 13b are highly reliable and have a long life. Furthermore, the bonding portion 13c that bonds the semiconductor element 2 to the first heat dissipation substrate 4 can be formed using a plate-shaped bonding material 13, but a paste-like bonding material 13 may also be used to improve productivity. The paste-like bonding material 13 may be applied to the surface of the first heat dissipation substrate 4 by, for example, screen printing.

[0035] As shown in Fig. 4, a plating layer 12 may be provided on the outer periphery of the electrodes 3, terminals 7, second heat dissipation substrate 5, and heat dissipation block 6 of the semiconductor element 2 on the surfaces that come into contact with the bonding material 13. Fig. 4 is a partially enlarged cross-sectional view showing a modification of the semiconductor device 1 shown in Figs. 1 and 2. Fig. 4 corresponds to Fig. 2. The plating layer 12 may be any one selected from the group consisting of a nickel (Ni) plating layer, a silver (Ag) plating layer, and a tin (Sn) plating layer. The thickness of the plating layer 12 is 0.001 mm or more and 0.002 mm or less. In Figure 4, the plating layer 12 is formed over the entire interface between the joint 13a and the electrodes 3 and terminals 7 of the semiconductor element 2, the second heat dissipation substrate 5, and the outer periphery of the heat dissipation block 6, but the plating layer 12 may be provided only on part of the interfaces between the joint 13a and the electrodes 3 and terminals 7a of the semiconductor element 2, the second heat dissipation substrate 5, and the outer periphery of the heat dissipation block 6, and the interfaces between the joint 13b and the first heat dissipation substrate 4, terminals 7b, and the outer periphery of the heat dissipation block 6.

[0036] <Method of manufacturing a semiconductor device> 5 is a flowchart illustrating a manufacturing method of the semiconductor device 1 according to the first embodiment. The manufacturing method of the semiconductor device 1 will be described below. As shown in FIG. 5, the manufacturing method of the semiconductor device 1 includes a step (S1) of preparing a heat dissipation substrate and a semiconductor element. In this step (S1), components required for the steps described below, such as a first heat dissipation substrate 4, a second heat dissipation substrate 5, a semiconductor element 2, a heat dissipation block 6, terminals 7, and a bonding material 13, are prepared.

[0037] Next, a first mounting step (S2) is performed. In this step (S2), the semiconductor element 2 is mounted on the surface of the first heat dissipation substrate 4 via a bonding material 13 serving as a first bonding material. Specifically, first, a plate-shaped bonding material 13 corresponding to the size of the flat surface of the semiconductor element 2 is placed at a predetermined position on the surface of the first heat dissipation substrate 4. Then, the semiconductor element 2 is mounted on the bonding material 13. If necessary, a dedicated jig for positioning and fixing the first heat dissipation substrate 4, bonding material 13, and semiconductor element 2 may be used to prevent misalignment. The dedicated jig is made of, for example, a carbon material. The dedicated jig has openings (not shown) for arranging the first heat dissipation substrate 4, bonding material 13, and semiconductor element 2 so that these components can be easily positioned.

[0038] Next, the first bonding step (S3) is performed. In this step (S3), the semiconductor element 2 and the first heat dissipation substrate 4 are bonded via the bonding material 13. Specifically, the first heat dissipation substrate 4 carrying the bonding material 13 and the semiconductor element 2 is placed in a reflow device for heating and cooling. The bonding material 13 is then melted by heating in the reflow device. The first heat dissipation substrate 4 carrying the bonding material 13 and the semiconductor element 2 is then cooled. As a result, the semiconductor element 2 and the first heat dissipation substrate 4 are bonded by the bonding portion 13c formed by the solidified bonding material 13. Note that heating and cooling must be performed according to a temperature profile corresponding to the material composition of the bonding material 13 (e.g., solder, sintered material, adhesive, etc.). If a dedicated jig such as the one described above is used, the dedicated jig is also placed in the reflow device together with the first heat dissipation substrate 4, and heating and cooling are performed. Note that the atmosphere inside the reflow device during heating can be controlled using nitrogen, formic acid, etc.

[0039] Next, a metal wire wiring step (S4) is performed. In this step (S4), a wire bonding device is used to connect the terminal 7c to be connected to the outside and the electrode 3, which is the control electrode of the semiconductor element 2, via a metal wire wiring 14 (see FIG. 1).

[0040] Next, a second mounting step (S5) is performed. In this step (S5), the heat dissipation block 6 and the terminal 7a (see FIG. 1) are arranged on the electrode 3 (see FIG. 2) of the semiconductor element 2 via a bonding material 13 serving as a second bonding material. The bonding material 13 is a plate-shaped bonding material having a size corresponding to the size of the electrode 3 of the semiconductor element 2. A first through hole 8a is formed in the terminal 7a. The terminal 7a is positioned so that the first through hole 8a is located on the bonding material 13. Thereafter, the second heat dissipation substrate 5 is mounted on the heat dissipation block 6 mounted on the electrode 3 of the semiconductor element 2 via a bonding material 13 serving as a third bonding material. Furthermore, the heat dissipation block 6 and the terminal 7b (see FIG. 1) are arranged on the surface of the first heat dissipation substrate 4 via the plate-shaped bonding material 13. The terminal 7b has a first through hole 8a formed in it. The terminal 7b is positioned so that the first through hole 8a is located on the bonding material 13. If necessary, a special jig may be used to position and fix the bonding material 13 mounted on the electrode 3 of the semiconductor element 2, the bonding material 13 mounted on the surface of the first heat dissipation substrate 4, the terminal 7a, and the terminal 7b so that they do not shift position.

[0041] Next, a second bonding step (S6) is performed. In this step (S6), the electrodes 3, terminals 7a, and second heat dissipation substrate 5 of the semiconductor element 2 are bonded together via the bonding material 13. Similarly, the first heat dissipation substrate 4 and terminals 7b are bonded together. Specifically, the first heat dissipation substrate 4 carrying the bonding material 13, terminals 7a, 7b, and second heat dissipation substrate 5 is placed in a reflow device for heating and cooling. Next, the bonding material 13 is melted by heating in the reflow device. Note that the heating temperature at this time is lower than the heating temperature in the first bonding step (S3). Thereafter, the melted bonding material 13 is cooled, bonding the semiconductor element 2, terminals 7a, and second heat dissipation substrate 5 to each other, forming a bonding portion 13a. Similarly, the first heat dissipation substrate 4 and terminals 7b are bonded together, forming a bonding portion 13b. Note that heating and cooling are performed according to a temperature profile corresponding to the material composition of the bonding material 13 (e.g., solder, sintered material, adhesive, etc.). The melting point of the bonding material 13 melted in this step (S6) is lower than the melting point of the bonding material 13 constituting the bonding portion 13c used to bond the first heat dissipation substrate 4 and the semiconductor element 2. This is because the heating in this step (S6) does not melt the bonding material 13 that has already bonded the first heat dissipation substrate 4 and the semiconductor element 2 in the first bonding step (S3).

[0042] Next, the encapsulation step (S7) is performed. In this step (S7), the semiconductor element 2 is encapsulated with encapsulating resin 16 by transfer molding. Specifically, tablet-shaped encapsulating resin 16 and insulating heat dissipation sheet 15 (see FIG. 1) are prepared. The insulating heat dissipation sheet 15 is placed in a mold of a transfer molding device. Next, the semiconductor element 2, the first heat dissipation substrate 4 to which terminals 7a, 7b, and 7c are bonded, and the second heat dissipation substrate 5 bonded to the first heat dissipation substrate 4 are placed on the insulating heat dissipation sheet 15. Next, the insulating heat dissipation sheet 15 is placed on the bottom surface of the second heat dissipation substrate 5. After that, the mold consisting of an upper mold and a lower mold are clamped to form a sealed internal space, and the tablet-shaped encapsulating resin 16 is poured into the device. Next, the mold is heated, causing the insulating heat dissipation sheet 15 to adhere to the first heat dissipation substrate 4 and the second heat dissipation substrate 5, respectively. At the same time, the semiconductor element 2, the first heat dissipation substrate 4, the second heat dissipation substrate 5, and the terminals 7a, 7b, and 7c are sealed with molten sealing resin 16, except for portions of the terminals 7a, 7b, and 7c. Next, a curing process is performed to harden the sealing resin 16. If the terminals 7a, 7b, and 7c are formed from lead frames, the tie bars, resin, and lead frame frames are cut. Next, portions (tips) of the terminals 7a, 7b, and 7c protruding from the sealing resin 16 are formed and bent. Finally, an inspection is performed to determine whether the electrical characteristics of the semiconductor device 1 are met. In this manner, the semiconductor device 1 shown in FIGS. 1 and 2 is manufactured.

[0043] Next, modified examples of the method for manufacturing the semiconductor device 1 will be described. Fig. 6 is a partially enlarged cross-sectional view of the semiconductor device 1 before the second bonding step (S5). Fig. 7 is a partially enlarged cross-sectional view of the semiconductor device 1 after the second bonding step (S6). The modified examples of the method for manufacturing the semiconductor device 1 described below basically include the same steps as the method for manufacturing the semiconductor device 1 shown in Fig. 5, but the steps after the second mounting step (S5) shown in Fig. 5 are different. The modified examples of the method for manufacturing the semiconductor device 1 will be described below.

[0044] First, the same steps (S1) to (S4) shown in Fig. 5 are performed. Next, a second mounting step (S5) is performed. This step (S5) differs from the step (S5) shown in Fig. 5 in that the heat dissipation block 6 is mounted directly on the electrodes 3 of the semiconductor element 2 without the bonding material 13 as the second bonding material. In other words, after the second mounting step (S5), the bonding material 13 is mounted only on the heat dissipation block 6, as shown in Fig. 6.

[0045] In the next second bonding step (S6), the bonding material 13 mounted on the heat dissipation block 6 melts when heated in the reflow machine, and the bonding material 13 wets and spreads toward the electrodes 3 of the semiconductor element 2 so as to cover the outer periphery of the heat dissipation block 6. Then, by cooling the molten bonding material 13, as shown in Fig. 7, the electrodes 3 of the semiconductor element 2 and the first heat dissipation block main surface 6a of the heat dissipation block 6 are directly connected, and a bonding portion 13a is formed so that the second heat dissipation block main surface 6b and the heat dissipation block side surface 6c are covered with the bonding material 13 as a third bonding material. In particular, when the bonding material 13 is solder, the wettability of the solder causes the bonding material 13 to wet and spread when heated in the reflow machine, making it easy to form the bonding portion 13a shown in Fig. 7.

[0046] Although the second heat dissipation board 5 and the heat dissipation block 6 are bonded via the bonding material 13, after cooling, the weight of the second heat dissipation board 5 may cause the second heat dissipation block main surface 6b facing the second heat dissipation board 5 to be in direct contact with the second heat dissipation board 5. In other words, the heat dissipation block side surface 6c of the heat dissipation block 6 and the second heat dissipation board 5 may be bonded with the bonding material 13, and the second heat dissipation block main surface 6b of the heat dissipation block 6 may be in contact with the second heat dissipation board 5. Furthermore, in order to suppress crack propagation, it is preferable to perform R processing or C-chamfering on the corners 6d of the heat dissipation block 6.

[0047] Thereafter, the sealing step (S6a) is carried out in the same manner as the step (S7) shown in Fig. 5. In this manner, the semiconductor device 1 shown in Fig. 7 can be obtained.

[0048] <Action and effect> A semiconductor device 1 according to the present disclosure includes a semiconductor element 2, a first heat dissipation substrate 4, a second heat dissipation substrate 5, and a heat dissipation block 6. The semiconductor element 2 has electrodes 3. The semiconductor element 2 is mounted on the first heat dissipation substrate 4. The heat dissipation block 6 is disposed so as to face the electrodes 3 of the semiconductor element 2. The second heat dissipation substrate 5 is disposed on the opposite side of the heat dissipation block 6 from the electrodes 3 of the semiconductor element 2. A bonding material 13 covers a heat dissipation block side surface 6c, which is a side surface of the heat dissipation block 6, and is in contact with the electrodes 3 of the semiconductor element 2 and the second heat dissipation substrate 5.

[0049] In this way, even if cracks occur in the bonding material 13 due to stress or strain during operation of the semiconductor device 1, the heat dissipation block 6, which is stronger than the bonding material 13, prevents the cracks from growing, greatly reducing the possibility of breakage during operation of the semiconductor device 1. Furthermore, since the bonding material 13 is arranged to cover not only a portion of the heat dissipation block 6 but also the side surface 6c of the heat dissipation block 6, the strength is improved by the amount of the bonding material 13. As a result, a highly reliable and long-life semiconductor device 1 can be obtained. The above-mentioned effects are obtained not only at the bonding portion 13a but also at the bonding portion 13b.

[0050] The semiconductor device 1 includes a terminal 7a having a first through hole 8a. The terminal 7a has a first terminal main surface 10a and a second terminal main surface 10b. The first terminal main surface 10a faces the electrode 3 of the semiconductor element 2. The second terminal main surface 10b is located opposite the first terminal main surface 10a. The first through hole 8a is formed to extend from the first terminal main surface 10a to the second terminal main surface 10b. The terminal 7 is disposed between the electrode 3 of the semiconductor element 2 and the second heat dissipation substrate 5 so that the heat dissipation block 6 is disposed inside the first through hole 8a. A bonding material 13 is in contact with the terminal 7.

[0051] In this way, the semiconductor device 1 can be electrically connected to a circuit board or another semiconductor device via the terminal 7. Furthermore, even if a crack occurs in the bonding material 13 at the interface between the bonding material 13 and the first through hole 8a, the heat dissipation block 6 prevents the crack from growing, greatly reducing the possibility of disconnection during operation of the semiconductor device 1.

[0052] In the semiconductor device 1, as shown in Fig. 2, the bonding material 13 extends from inside the first through hole 8a onto the first terminal main surface 10a and the second terminal main surface 10b. In this way, the bonding portion 13a formed by the bonding material 13 has a rivet-like shape, and the area of ​​the bonding interface between the bonding material 13 and the terminal 7 increases. This increases the bonding strength of the bonding portion 13a. The above-mentioned effects are obtained not only in the bonding portion 13a but also in the bonding portion 13b.

[0053] The material constituting the bonding material 13 used in the semiconductor device 1 may include any one selected from the group consisting of solder, a sintered material, and an adhesive. In this way, when the bonding material 13 is solder, the wettability of the solder causes the bonding material 13 to adhere closely to the side surface of the first through hole 8a of the terminal 7, thereby ensuring the bonding strength between the bonding portion 13a and the terminal 7.

[0054] When the bonding material 13 is a sintered material using metal particles containing silver (Ag) or copper (Cu), the bonding portion 13a has excellent heat dissipation properties. Furthermore, because the first through-holes 8a are open, the solvent contained in the sintered material is sufficiently volatilized during the heating process for forming the bonding portion 13a, allowing the solvent to be removed from the bonding portion 13a. As a result, the first through-holes 8a can be reliably covered with the bonding material 13, and voids can be prevented from forming in the bonding portion 13a. When the bonding material 13 is a sintered material or adhesive containing resin, the elasticity of the bonding portions 13a and 13b can be reduced. As a result, a semiconductor device 1 with high reliability and a long life can be obtained.

[0055] In the semiconductor device 1, any one selected from the group consisting of the electrodes 3, terminals 7, second heat dissipation substrate 5, and heat dissipation block 6 of the semiconductor element 2 includes a plating layer 12 formed in a region in contact with the bonding material 13. This improves adhesion to the bonding material 13 at the interface with the bonding portions 13a and 13b, thereby preventing the occurrence of unbonded portions. As a result, the bonding strength of the bonding portions 13a and 13b can be ensured. In particular, when the bonding material 13 is solder, the plating layer 12 improves the wettability of the solder. For example, when a recess 9 is provided on the side surface of the first through hole 8a as in the fifth and sixth embodiments described below, the bonding material 13 can be sufficiently adhered to the recess 9.

[0056] In the semiconductor device 1, the plating layer 12 is primarily composed of at least one selected from the group consisting of nickel, silver, gold, and tin. In this case, when solder is used as the bonding material 13, forming the plating layer 12 can promote the wetting and spreading of the solder. Furthermore, when a sintered material is used as the bonding material 13, the bonding between the sintered material and the plating layer 12 can be promoted. In this way, the bonding strength between the bonding material 13 and a member such as the electrode 3 on which the plating layer 12 is formed can be improved.

[0057] In the semiconductor device 1, the first heat dissipation substrate 4 and the second heat dissipation substrate 5 are mainly composed of aluminum or copper. In this case, the heat dissipation performance of the semiconductor device 1 can be improved, and the semiconductor element 2 can be effectively cooled. As a result, deterioration of the characteristics of the semiconductor element 2 (such as switching loss) can be suppressed.

[0058] In the semiconductor device 1, the first heat dissipation substrate 4 and the second heat dissipation substrate 5 each include an insulating heat dissipation sheet 15 connected to the opposing surface of the substrate. The insulating heat dissipation sheet 15 includes an insulating layer 15a and a metal layer 15b, and the metal layer 15b is laminated with the insulating layer 15a. In this case, a cooler including heat dissipation fins can be connected via the insulating heat dissipation sheet 15. This improves the cooling performance of the semiconductor device 1.

[0059] The semiconductor device 1 includes a sealing resin 16 that covers the semiconductor element 2, the first heat dissipation substrate 4, and the second heat dissipation substrate 5. In this case, the sealing resin 16 ensures insulation of the semiconductor element 2 and the like, and also protects them from external impacts and the like.

[0060] In the semiconductor device 1, the semiconductor element 2 is an insulated gate bipolar transistor. In this case, the semiconductor device 1 can be applied to a power conversion device or the like.

[0061] In the semiconductor device 1, the semiconductor element 2 includes a wide bandgap semiconductor. In this case, a semiconductor device 1 that is more efficient and can withstand high temperatures than a semiconductor element 2 that uses silicon as a base material can be realized.

[0062] A method for manufacturing a semiconductor device 1 according to the present disclosure includes a preparation step (S1), a mounting step (S2) of a semiconductor element 2, a bonding step (S3) of the semiconductor element 2, a connecting step (S4) of metal wire wiring 14, a mounting step (S5) of a second heat dissipation substrate 5, a bonding step (S6) of the second heat dissipation substrate 5, and a sealing step (S7). In the preparation step (S1), a semiconductor element 2 having a first heat dissipation substrate 4 and electrodes 3 is prepared. In the mounting step (S2), the semiconductor element 2 is mounted on the first heat dissipation substrate 4 via a bonding material 13 serving as a first bonding material. In the bonding step (S3), the bonding material 13 is heated to bond the semiconductor element 2 to the first heat dissipation substrate 4 via the bonding material 13. In the connecting step (S4) of the metal wire wiring 14, the metal wire wiring 14 is connected to the electrodes 3 of the semiconductor element 2. In the step (S5) of mounting the second heat dissipation substrate 5, the heat dissipation block 6 is mounted on the electrodes 3 of the semiconductor element 2 via a bonding material 13 serving as a second bonding material, and the second heat dissipation substrate 5 is further mounted on the heat dissipation block 6 via a bonding material 13 serving as a third bonding material. In the step (S6) of bonding the second heat dissipation substrate 5, the second bonding material and the bonding material 13 serving as the third bonding material are heated so that the bonding material 13 covers the side surfaces of the heat dissipation block 6 and bonds the electrodes 3 of the semiconductor element 2 to the second heat dissipation substrate 5. In the sealing step (S7), the semiconductor element 2 is sealed with a sealing resin 16 by transfer molding. In this manner, the semiconductor device 1 according to the present disclosure can be obtained.

[0063] Embodiment 2 <Configuration of semiconductor device> Fig. 8 is a cross-sectional view of a semiconductor device 1 according to embodiment 2. Fig. 8 corresponds to Fig. 1. The semiconductor device 1 shown in Fig. 8 basically has the same configuration as the semiconductor device 1 shown in Figs. 1 and 2, but differs in that there is no terminal 7a having a first through-hole 8a, and a part of the second heat dissipation substrate 5 extends outward from the surface of the sealing resin 16 so as to function as a terminal that can be connected to an external device externally.

[0064] <Action and effect> In this way, the same effects as those of the semiconductor device 1 according to the first embodiment can be obtained, and the component of the terminal 7a having the first through hole 8a can be reduced. This reduces the costs of materials and manufacturing required for the semiconductor device 1, and simplifies the assembly of the semiconductor device 1. Note that the portions of the terminal 7b and the second heat dissipation substrate 5 that extend outward from the surface of the sealing resin 16 are arranged apart from each other outside the sealing resin 16 so as to ensure as much spatial distance as possible between them.

[0065] <Configuration of Modified Example> Figure 9 is a cross-sectional view of a modified example of semiconductor device 1 according to embodiment 2. Figure 9 corresponds to Figure 1. Semiconductor device 1 shown in Figure 9 basically has the same configuration as semiconductor device 1 shown in Figures 1 and 2, but differs in that cooler 17 is connected to metal layer 15b of insulating heat dissipation sheet 15. Specifically, cooler 17 is connected to metal layer 15b of two insulating heat dissipation sheets 15 that are exposed from sealing resin 16, respectively, via joints 13d.

[0066] If the operating temperature of the semiconductor element 2 exceeds the rated value, the switching performance of the semiconductor element 2 will deteriorate, and in the worst case, thermal runaway will occur, damaging the semiconductor element 2. For this reason, by providing not only the first heat dissipation board 4 and the second heat dissipation board 5, which have excellent thermal conductivity, but also a cooler 17 via an insulating heat dissipation sheet 15, the heat dissipation and cooling properties of the semiconductor device 1 can be improved. For example, a material selected from the group consisting of the above-mentioned bonding material 13, thermal grease, and TIM (Thermal Interface Material) can be placed on the underside of the insulating heat dissipation sheet 15, and the first heat dissipation board 4 and the second heat dissipation board can be connected to their respective coolers by bonding parts 13d made of this material.

[0067] The cooler 17 is made of a metal with excellent thermal conductivity, such as aluminum (Al). The cooler 17 has multiple heat dissipation fins 18. The multiple heat dissipation fins 18 are formed on the cooler 17 so as to protrude from a base portion connected to the insulating heat dissipation sheet 15. The cooling method for the cooler 17 may be air-cooled or water-cooled. Alternatively, the first heat dissipation substrate 4 and the cooler 17, or the second heat dissipation substrate 5 and the cooler 17, may be integrated without forming the joint 13d. In this case, the first heat dissipation substrate 4 and the second heat dissipation substrate 5 are integrated with the cooler 17, eliminating the need for the joint 13d. This eliminates the interface caused by the joint 13d, thereby eliminating thermal resistance at the interface. As a result, the semiconductor device 1 improves heat dissipation and cooling from the heat-generating semiconductor element 2. When the first heat dissipation substrate 4 and the cooler 17, or the second heat dissipation substrate 5 and the cooler 17, are integrated, a flat film-like insulating layer 15a is provided between the first heat dissipation substrate 4 and the cooler 17, and between the second heat dissipation substrate 5 and the cooler 17. The material constituting the insulating layer 15a may be an inorganic material selected from the group consisting of alumina (Al2O3), aluminum nitride (AlN), silicon nitride (Si3N4), silicon dioxide (SiO2), or boron nitride (BN), or an organic material selected from the group consisting of epoxy resin, polyimide resin, acrylic resin, and polyphenylene sulfide (PPS) resin.

[0068] <Action and effect> The semiconductor device 1 may include a cooler 17 connected to the first heat dissipation substrate 4 or the second heat dissipation substrate 5 via an insulating heat dissipation sheet 15. This can improve the heat dissipation and cooling properties of the semiconductor element 2 that generates heat in the semiconductor device 1.

[0069] The semiconductor device 1 may include a cooler 17 connected to the first heat dissipation substrate 4 or the second heat dissipation substrate 5. Specifically, the semiconductor device 1 may include a cooler 17 connected directly to the first heat dissipation substrate 4 or the second heat dissipation substrate 5 without the insulating heat dissipation sheet 15. In this way, the expensive insulating heat dissipation sheet 15 is not required in the manufacture of the semiconductor device 1, and therefore the manufacturing cost of the semiconductor device 1 can be reduced.

[0070] Embodiment 3 <Configuration of semiconductor device> FIG. 10 is a partially enlarged cross-sectional view of the semiconductor device 1 according to the third embodiment before the bonding material 13 melts. FIG. 11 is a partially enlarged cross-sectional view of the semiconductor device 1 according to the third embodiment after the bonding material 13 has cooled. FIG. 11 corresponds to FIG. 2. FIG. 12 is a partially enlarged cross-sectional view of a modified example of the semiconductor device 1 according to the third embodiment. The semiconductor device 1 shown in FIG. 11 basically has the same configuration as the semiconductor device 1 shown in FIGS. 1 and 2, but differs from the semiconductor device 1 shown in FIGS. 1 and 2 in that the shape of the heat dissipation block 6 widens downward and that the heat dissipation block 6 is in direct contact with the electrodes 3 of the semiconductor element 2. Specifically, the heat dissipation block 6 has a shape in which the surface area of ​​the first heat dissipation block main surface 6a is larger than the surface area of ​​the second heat dissipation block main surface 6b. The extension direction of the heat dissipation block side surface 6c is inclined relative to the first heat dissipation block main surface 6a. The heat dissipation block side surface 6c is inclined so as to face the second heat dissipation substrate 5. Furthermore, the first heat dissipation block main surface 6a of the heat dissipation block 6 is in direct contact with the electrodes 3 of the semiconductor element 2. A bonding portion 13a made of a bonding material 13 extends from the heat dissipation block side surface 6c onto the electrodes 3 of the semiconductor element 2.

[0071] The semiconductor device manufacturing method shown in FIG. 11 may be a modified version of the manufacturing method of the semiconductor device 1 according to the first embodiment. In this case, steps (S1) to (S4) shown in FIG. 5 are first performed. Then, as shown in FIG. 10, in a second mounting step (S5), a heat dissipation block 6 is mounted on the electrodes 3 of the semiconductor element 2 without a bonding material 13 serving as a second bonding material. Furthermore, a bonding material 13 serving as a third bonding material is mounted on the main surface 6b of the second heat dissipation block. Then, in a second bonding step (S6), heating and cooling are performed using a reflow device, thereby obtaining the structure shown in FIG. 11. Specifically, the main surface 6a of the first heat dissipation block is directly connected to the electrodes 3 of the semiconductor element 2. Furthermore, the main surface 6b and the side surface 6c of the second heat dissipation block are covered with the bonding material 13, and a bonding portion 13a is formed where a portion of the bonding material 13 contacts the electrodes 3 of the semiconductor element 2, the terminals 7a, and the second heat dissipation substrate 5. Thereafter, the sealing step (S7) shown in FIG. 5 is carried out, whereby the semiconductor device according to the third embodiment can be obtained.

[0072] <Action and effect> In the semiconductor device 1, the heat dissipation block 6 has a first heat dissipation block main surface 6a facing the electrodes 3 of the semiconductor element 2 and a second heat dissipation block main surface 6b opposite the first heat dissipation block main surface 6a. A first surface area, which is the surface area of ​​the first heat dissipation block main surface 6a, is larger than a second surface area, which is the surface area of ​​the second heat dissipation block main surface 6b.

[0073] In this way, when assembling the semiconductor device 1, the heat dissipation block 6 has a shape that widens downward, so the center of gravity of the heat dissipation block 6 is located relatively lower (toward the electrode 3). Furthermore, because the surface area of ​​the first heat dissipation block main surface 6a (the surface that is mounted on the electrode 3) is larger than the surface area of ​​the second heat dissipation block main surface 6b, the heat dissipation block 6 can be mounted freestanding on the electrode 3 of the semiconductor element 2. This improves stability and workability when mounting the heat dissipation block 6 on the electrode 3 of the semiconductor element 2. The heat dissipation block 6 disposed inside the first through hole 8a of the terminal 7b may also have a similar shape.

[0074] As a modification of the semiconductor device according to the third embodiment, as shown in FIG. 12, the first through hole 8a of the terminal 7a may also have a shape that widens downward to match the downwardly flared shape of the heat dissipation block 6. Specifically, the terminal 7a has a first opening area S1 of the first through hole 8a on the first terminal main surface 10a and a second opening area S2 of the first through hole 8a on the second terminal main surface 10b. The first through hole 8a has a shape in which the second opening area S2 is smaller than the first opening area S1. This facilitates positioning of the heat dissipation block 6. The shape of the first through hole 8a in the terminal 7b may also be the shape shown in FIG. 12.

[0075] Embodiment 4 <Configuration of semiconductor device> FIG. 13 is a partially enlarged cross-sectional view of a semiconductor device 1 according to a fourth embodiment. FIG. 13 corresponds to FIG. 2. The semiconductor device 1 shown in FIG. 13 has a configuration similar to that of the semiconductor device 1 shown in FIGS. 1 and 2, except for the shape of the first through hole 8a of the terminal 7a. Specifically, in the semiconductor device 1 shown in FIG. 13, the first opening area S1 and the second opening area S2 of the first through hole 8a are larger than the minimum opening area S3 in a narrow region L located in the middle region in the extension direction of the first through hole 8a. Here, the minimum opening area S3 is the area of ​​the first through hole 8a in the radial direction in the narrow region L. The minimum opening area S3 is the smallest area within the first through hole 8a in the radial direction. The first opening area S1 is the area of ​​the first through hole 8a on the first terminal main surface 10a. The second opening area S2 is the area of ​​the first through hole 8a on the second terminal main surface 10b.

[0076] The first region, narrow region L, is an area inside first through hole 8a and is a region separated by a first distance l from first terminal main surface 10a in direction A, which is the direction along the central axis R of first through hole 8a. Narrow region L has a minimum hole area S3, which is the smallest hole area in first through hole 8a. The side surfaces of first through hole 8a are inclined relative to first terminal main surface 10a and second terminal main surface 10b. That is, the side surfaces of first through hole 8a intersect with first terminal main surface 10a and second terminal main surface 10b at an angle so that the hole areas gradually increase from narrow region L toward first terminal main surface 10a and second terminal main surface 10b. The shape of first through hole 8a in terminal 7b may also be the shape shown in FIG. 13.

[0077] <Action and effect> In the semiconductor device 1, the first through hole 8a has a narrow region L as a first region where the area of ​​the first through hole 8a in the radial direction is minimum. Compared to the minimum hole area S3, which is the area of ​​the narrow region L, the first opening area S1 of the first through hole 8a on the first terminal main surface 10a and the second opening area S2 of the first through hole 8a on the second terminal main surface 10b are larger.

[0078] In this way, when the heat dissipation block 6 is mounted on the electrode 3 of the semiconductor element 2, the heat dissipation block 6 can be positioned in the narrow area L of the first through hole 8a. This improves the assembly efficiency in the manufacturing process of the semiconductor device 1.

[0079] <Configuration of Modified Example> Fig. 14 is a partially enlarged cross-sectional view of a modified example of the semiconductor device 1 according to the fourth embodiment. Fig. 14 corresponds to Fig. 13. The semiconductor device 1 shown in Fig. 14 basically has the same configuration as the semiconductor device 1 shown in Fig. 13, but the shape of the first through hole 8a of the terminal 7a is different from that of the semiconductor device shown in Figs. 1 and 2. Specifically, a recess 9 is formed on the inner circumferential surface of the first through hole 8a.

[0080] The recess 9 is a concave-shaped step portion and is composed of a first step surface 9a, a second step surface 9b, and a third step surface 9c. The first step surface 9a and the second step surface 9b each extend so as to intersect with the side surface of the first through hole 8a. The first step surface 9a and the second step surface 9b face each other and are parallel to each other. The first step surface 9a and the second step surface 9b extend in a direction perpendicular to the side surface of the first through hole 8a. The third step surface 9c extends in a direction along the side surface of the first through hole 8a. The extension direction of the third step surface 9c is, for example, parallel to the extension direction of the side surface of the first through hole 8a. The third step surface 9c intersects with the first step surface 9a and the second step surface 9b. The third step surface 9c is located at a position in the recess 9 that is farthest from the central axis R of the first through hole 8a. Such recesses 9 are formed on the inner circumferential surface of the first through hole 8a by a chemical processing method such as etching or a physical processing method such as machining. The recesses 9 are formed on the inner circumferential surface of the first through hole 8a so as to extend in the circumferential direction about the central axis R. The recesses 9 may be formed on the entire inner circumferential surface of the first through hole 8a, or may be formed on only a portion of the inner circumferential surface in the circumferential direction.

[0081] The bonding material 13 constituting the bonding portion 13a is disposed so as to cover the outer periphery of the heat dissipation block 6 and fill the inside of the first through-hole 8a including the inside of the recess 9. The bonding material 13 is connected to the electrodes 3 and terminals 7a of the semiconductor element 2 and the second heat dissipation substrate 5.

[0082] <Action and effect> In the semiconductor device 1, the terminal 7 has a recess 9 formed on the inner circumferential surface of the first through hole 8a. By providing the recess 9 on the inner circumferential surface of the first through hole 8a, the bonding area between the terminal 7a and the bonding portion 13a is increased, thereby providing an anchoring effect. As a result, the bonding strength of the bonding portion 13a is significantly improved, resulting in a semiconductor device 1 with high reliability and long life. At least one recess 9 is sufficient to provide the anchoring effect. To further enhance the anchoring effect, it is preferable to provide multiple recesses 9. Furthermore, when a plating layer 12 is provided on the side surface of the first through hole 8a, including the recess 9, as shown in FIG. 4, the bonding material 13 fills even the smallest parts of the recess 9, effectively improving the bonding strength.

[0083] Embodiment 5 <Configuration of semiconductor device> FIG. 15 is a partially enlarged cross-sectional view of a semiconductor device 1 according to a fifth embodiment. FIG. 15 corresponds to FIG. 2. The semiconductor device 1 shown in FIG. 15 basically has the same configuration as the semiconductor device 1 shown in FIGS. 1 and 2, but the shape of the heat dissipation block 6 is different from that of the semiconductor device 1 shown in FIGS. 1 and 2. Specifically, in the semiconductor device shown in FIG. 15, a second through-hole 8b is formed in the heat dissipation block 6, penetrating from the first heat dissipation block main surface 6a to the second heat dissipation block main surface 6b. A bonding portion 13a is formed so that the bonding material 13 fills not only the outer periphery of the heat dissipation block 6 but also the interior of the second through-hole 8b.

[0084] 16 to 18, the configuration of the heat dissipation block 6 in which the second through holes 8b are provided can be freely combined with a shape of the heat dissipation block 6 and a shape of the first through holes 8a of the terminals 7a that are different from the configuration shown in FIG. 15. FIGS. 16 to 18 are partially enlarged cross-sectional views showing modifications of the semiconductor device according to the fifth embodiment. The semiconductor devices shown in FIGS. 16 to 18 basically have the same configuration as the semiconductor device shown in FIG. 15, but the shape of the heat dissipation block 6 or the shape of the first through holes 8a is different from that of the semiconductor device shown in FIG. 15.

[0085] For example, as shown in Fig. 16, second through holes 8b may be formed in a heat dissipation block 6 having a downwardly expanding shape. The configurations of joints 13a and terminals 7a in the configuration shown in Fig. 16 are similar to the configurations of joints 13a and terminals 7a in the semiconductor device shown in Fig. 11.

[0086] 17, the shape of first through hole 8a, in which heat dissipation block 6 having second through hole 8b formed therein, may be such that first opening area S1 and second opening area S2 are larger than minimum opening area S3 in narrow region L. Also, the side surface of first through hole 8a may intersect first terminal main surface 10a and second terminal main surface 10b at an angle so that the opening area gradually increases from narrow region L toward first terminal main surface 10a and second terminal main surface 10b. The configurations of joint 13a and terminal 7a in the configuration shown in FIG. 16 are similar to the configurations of joint 13a and terminal 7a in the semiconductor device shown in FIG. 13.

[0087] 18, a recess 9 may be provided on the inner circumferential surface of the first through hole 8a in which the heat dissipation block 6 having the second through hole 8b formed therein is disposed. The configurations of the joints 13a and terminals 7a in the configuration shown in FIG. 18 are the same as the configurations of the joints 13a and terminals 7a in the semiconductor device shown in FIG.

[0088] <Action and effect> In the semiconductor device 1, the heat dissipation block 6 is formed with a second through-hole 8b that penetrates from the first heat dissipation block main surface 6a to the second heat dissipation block main surface 6b.

[0089] In this way, the bonding portion 13a can be formed so that the bonding material 13 fills not only the outer periphery of the heat dissipation block 6 but also the inside of the second through hole 8b. This improves the bonding strength between the electrode 3 of the semiconductor element 2 and the second heat dissipation substrate 5. As a result, a highly reliable and long-life semiconductor device 1 can be obtained.

[0090] Embodiment 6 In this embodiment, the semiconductor devices according to the above-described first to fifth embodiments are applied to a power conversion device. Although the present disclosure is not limited to a specific power conversion device, the following will describe a case where the present disclosure is applied to a three-phase inverter as a sixth embodiment.

[0091] FIG. 19 is a block diagram showing the configuration of a power conversion system to which the power conversion device according to this embodiment is applied.

[0092] The power conversion system shown in Fig. 19 is composed of a power source 24, a power conversion device 20, and a load 25. The power source 24 is a DC power source and supplies DC power to the power conversion device 20. The power source 24 can be composed of various components, such as a DC system, a solar cell, or a storage battery, or it may be composed of a rectifier circuit connected to an AC system or an AC / DC converter. The power source 24 may also be composed of a DC / DC converter that converts DC power output from the DC system into a predetermined power.

[0093] The power conversion device 20 is a three-phase inverter connected between a power source 24 and a load 25, and converts DC power supplied and input from the power source 24 into AC power and supplies the AC power to the load 25. As shown in Fig. 19 , the power conversion device 20 includes a main conversion circuit 21 that converts DC power into AC power and outputs it, a drive circuit 22 that outputs drive signals that drive each switching element of the main conversion circuit 21, and a control circuit 23 that outputs a control signal to the drive circuit 22 to control the drive circuit 22.

[0094] The load 25 is a three-phase electric motor driven by AC power supplied from the power conversion device 20. The load 25 is not limited to a specific application, but is an electric motor mounted on various electrical devices, such as a hybrid vehicle, an electric vehicle, a railroad car, an elevator, or an air conditioning device.

[0095] The power conversion device 20 will be described in detail below. The main conversion circuit 21 includes switching elements and freewheel diodes (not shown). By switching the switching elements, the DC power supplied from the power source 24 is converted into AC power and supplied to the load 25. There are various specific circuit configurations for the main conversion circuit 21. However, the main conversion circuit 21 according to this embodiment is a two-level, three-phase full-bridge circuit that can be configured with six switching elements and six freewheel diodes connected in anti-parallel to each switching element. The semiconductor device 1 according to any one of the above-mentioned first to fifth embodiments is applied to each switching element of the main conversion circuit 21. Two switching elements are connected in series to form upper and lower arms, and each upper and lower arm forms one phase (U phase, V phase, W phase) of the full-bridge circuit. The output terminals of each upper and lower arm, i.e., the three output terminals of the main conversion circuit 21, are connected to the load 25.

[0096] The drive circuit 22 generates drive signals for driving the switching elements of the main conversion circuit 21 and supplies them to the control electrodes of the switching elements of the main conversion circuit 21. Specifically, in accordance with control signals from a control circuit 23 (described later), the drive circuit 22 outputs to the control electrodes of each switching element a drive signal that turns the switching element on and a drive signal that turns the switching element off. When maintaining a switching element in the on state, the drive signal is a voltage signal (on signal) that is equal to or higher than the threshold voltage of the switching element, and when maintaining a switching element in the off state, the drive signal is a voltage signal (off signal) that is equal to or lower than the threshold voltage of the switching element.

[0097] The control circuit 23 controls the switching elements of the main conversion circuit 21 so that the desired power is supplied to the load 25. Specifically, it calculates the time (on time) that each switching element of the main conversion circuit 21 should be in the on state based on the power to be supplied to the load 25. For example, the main conversion circuit 21 can be controlled by PWM control, which modulates the on time of the switching elements according to the voltage to be output. The control circuit 23 then outputs a control command (control signal) to the drive circuit 22 so that an on signal is output to the switching element that should be in the on state at each point in time, and an off signal is output to the switching element that should be in the off state at each point in time. In accordance with this control signal, the drive circuit 22 outputs an on signal or an off signal as a drive signal to the control electrode of each switching element.

[0098] In the power conversion device according to this embodiment, a semiconductor device according to any one of embodiments 1 to 5 is applied as a switching element of the main conversion circuit 21, so that a highly reliable and long-life power conversion device can be realized.

[0099] In the present embodiment, a two-level power conversion device has been described, but the present embodiment is not limited to this and can be applied to various power conversion devices. In the present embodiment, a two-level power conversion device has been described, but a three-level or multi-level power conversion device may also be used. In addition, when power is supplied to a single-phase load, the present disclosure may be applied to a DC / DC converter or an AC / DC converter.

[0100] Furthermore, the power conversion device to which the present disclosure is applied is not limited to cases in which the above-mentioned load is an electric motor, but can also be used, for example, as a power supply device for an electric discharge machine, a laser processing machine, an induction heating cooker, or a contactless power supply system, and can also be used as a power conditioner for a solar power generation system, a power storage system, etc.

[0101] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. Unless there is a contradiction, at least two of the embodiments disclosed herein may be combined. The basic scope of the present disclosure is defined by the claims, not the above description, and is intended to include all modifications within the meaning and scope equivalent to the claims.

[0102] Various aspects of the present disclosure are summarized below as appendices. (Appendix 1) a semiconductor element having an electrode; a first heat dissipation substrate on which the semiconductor element is mounted; a heat dissipation block disposed opposite the electrode; a second heat dissipation substrate disposed on the opposite side of the heat dissipation block from the electrodes; a bonding material covering the side surface of the heat dissipation block and in contact with the electrode of the semiconductor element and the second heat dissipation substrate; (Appendix 2) The semiconductor device includes: a terminal having a first through hole; The terminal is a first terminal main surface facing the electrode of the semiconductor element; a second terminal main surface opposite the first terminal main surface, the first through hole is formed so as to reach from the first terminal main surface to the second terminal main surface, the terminal is disposed between the electrode of the semiconductor element and the second heat dissipation substrate so that the heat dissipation block is disposed inside the first through hole; 2. The semiconductor device according to claim 1, wherein the bonding material is in contact with the terminal. (Appendix 3) 3. The semiconductor device according to claim 2, wherein the bonding material extends from inside the first through hole onto the first terminal main surface and the second terminal main surface. (Appendix 4) 4. The semiconductor device according to claim 2, wherein the first through hole has a recess formed on an inner circumferential surface of the through hole. (Appendix 5) the first through hole has a first region in which the area of ​​the first through hole in a radial direction is minimum, With respect to the area in the first region, 5. The semiconductor device according to claim 2, wherein a first opening area of ​​the first through hole on the first terminal main surface and a second opening area of ​​the first through hole on the second terminal main surface are larger than each other. (Appendix 6) The heat dissipation block is a first heat dissipation block main surface facing the electrodes of the semiconductor element; a second heat dissipation block main surface opposite the first heat dissipation block main surface, 6. The semiconductor device according to claim 1, wherein a first surface area of ​​the first heat dissipation block main surface is larger than a second surface area of ​​the second heat dissipation block main surface. (Appendix 7) The heat dissipation block is a first heat dissipation block main surface facing the electrodes of the semiconductor element; a second heat dissipation block main surface opposite the first heat dissipation block main surface, The semiconductor device according to any one of claims 1 to 6, wherein the heat dissipation block has a second through hole formed so as to reach from the main surface of the first heat dissipation block to the main surface of the second heat dissipation block. (Appendix 8) 8. The semiconductor device according to claim 1, wherein the material constituting the bonding material includes any one selected from the group consisting of solder, a sintered material, and an adhesive. (Appendix 9) 6. The semiconductor device according to claim 2, wherein any one selected from the group consisting of the electrode, the terminal, the second heat dissipation substrate, and the heat dissipation block includes a plating layer formed in an area in contact with the bonding material. (Appendix 10) 10. The semiconductor device according to claim 9, wherein the plating layer is mainly composed of at least one selected from the group consisting of nickel, silver, gold, and tin. (Appendix 11) 11. The semiconductor device according to claim 1, wherein the first heat dissipation substrate and the second heat dissipation substrate are primarily made of aluminum or copper. (Appendix 12) The first heat dissipation substrate and the second heat dissipation substrate are Each of the insulating and heat-dissipating sheets is connected to the opposing surface of the other. The insulating and heat-dissipating sheet is an insulating layer; 12. The semiconductor device according to claim 1, further comprising a metal layer stacked on the insulating layer. (Appendix 13) 13. The semiconductor device according to claim 12, further comprising a cooler connected to the first heat dissipation substrate or the second heat dissipation substrate via the insulating heat dissipation sheet. (Appendix 14) 14. The semiconductor device according to claim 1, further comprising a cooler connected to the first heat dissipation substrate or the second heat dissipation substrate. (Appendix 15) 15. The semiconductor device according to claim 1, further comprising a sealing resin covering the semiconductor element, the first heat dissipation substrate, and the second heat dissipation substrate. (Appendix 16) 16. The semiconductor device according to claim 1, wherein the semiconductor element is an insulated gate bipolar transistor. (Appendix 17) 17. The semiconductor device according to claim 1, wherein the semiconductor element includes a wide bandgap semiconductor. (Appendix 18) a main conversion circuit including the semiconductor device according to Supplementary Note 1, which converts input power and outputs the converted power; a drive circuit that outputs a drive signal to the semiconductor device; a control circuit that outputs a control signal to the drive circuit to control the drive circuit; A power conversion device comprising: (Appendix 19) providing a first heat dissipation substrate, a second heat dissipation substrate, a heat dissipation block, and a semiconductor element having electrodes; Mounting the semiconductor element on the first heat dissipation substrate via a first bonding material; a step of heating the first bonding material to bond the semiconductor element to the first heat dissipation substrate via the first bonding material; The heat dissipation block is mounted on the electrode of the semiconductor element via a second bonding material, and further mounting a second heat dissipation substrate on the heat dissipation block via the third bonding material; and heating the second bonding material and the third bonding material so that the second bonding material and the third bonding material cover the side surfaces of the heat dissipation block and bond the electrodes to the second heat dissipation substrate. [Explanation of symbols]

[0103] REFERENCE SIGNS LIST 1 semiconductor device, 2 semiconductor element, 3 electrode, 4 first heat dissipation substrate, 5 second heat dissipation substrate, 6 heat dissipation block, 6a first heat dissipation block main surface, 6b second heat dissipation block main surface, 6c heat dissipation block side surface, 6d corner portion, 7, 7a, 7b, 7c terminal, 8a first through hole, 8b second through hole, 9 recess, 9a first step surface, 9b second step surface, 9c third step surface, 10a first terminal main surface, 10b second terminal main surface, 12 plating layer, 13 bonding material, 13a, 13b, 13c, 13d bonding portion, 14 metal wire wiring, 15 insulating heat dissipation sheet, 15a insulating layer, 15b metal layer, 16 sealing resin, 17 cooler, 18 fin, 20 power conversion device, 21 main conversion circuit , 22 drive times road, 23 Control Circuit road, 24 power supply, 25 load, l 1st distance, L narrow area, S1 1st opening area, S2 2nd opening area, S3 minimum hole area, R central axis.

Claims

1. a semiconductor element having an electrode; a first heat dissipation substrate on which the semiconductor element is mounted; a heat dissipation block disposed opposite the electrode; a second heat dissipation substrate disposed on an opposite side of the heat dissipation block from the electrodes; a bonding material covering a side surface of the heat dissipation block and in contact with the electrode of the semiconductor element and the second heat dissipation substrate; a terminal having a first through hole, The terminal is a first terminal main surface facing the electrode of the semiconductor element; a second terminal main surface opposite the first terminal main surface; the first through-hole is formed so as to reach from the first terminal main surface to the second terminal main surface, the terminal is disposed between the electrode of the semiconductor element and the second heat dissipation substrate so that the heat dissipation block is disposed inside the first through hole; The semiconductor device, wherein the bonding material is in contact with the terminal.

2. The semiconductor device according to claim 1 , wherein the bonding material extends from inside the first through hole onto the first terminal main surface and onto the second terminal main surface.

3. The semiconductor device according to claim 1 , wherein the first through hole has a recess formed on an inner circumferential surface of the first through hole.

4. the first through hole has a first region in which the area of ​​the first through hole in a radial direction is minimum, With respect to the area in the first region, 2. The semiconductor device according to claim 1, wherein a first opening area of ​​said first through hole on said first terminal main surface is larger than a second opening area of ​​said first through hole on said second terminal main surface.

5. The heat dissipation block is a first heat dissipation block main surface facing the electrodes of the semiconductor element; a second heat dissipation block main surface opposite the first heat dissipation block main surface, 5. The semiconductor device according to claim 1, wherein a first surface area of ​​the main surface of the first heat dissipation block is larger than a second surface area of ​​the main surface of the second heat dissipation block.

6. The heat dissipation block is a first heat dissipation block main surface facing the electrodes of the semiconductor element; a second heat dissipation block main surface opposite the first heat dissipation block main surface, 5. The semiconductor device according to claim 1, wherein the heat dissipation block has a second through hole formed so as to reach from the main surface of the first heat dissipation block to the main surface of the second heat dissipation block.

7. 5. The semiconductor device according to claim 1, wherein the material constituting the bonding material includes any one selected from the group consisting of solder, a sintered material, and an adhesive.

8. 5. The semiconductor device according to claim 1, wherein any one selected from the group consisting of the electrode, the terminal, the second heat dissipation substrate, and the heat dissipation block includes a plating layer formed in an area in contact with the bonding material.

9. 9. The semiconductor device according to claim 8, wherein said plating layer is mainly composed of at least one selected from the group consisting of nickel, silver, gold, and tin.

10. The semiconductor device according to claim 1 , wherein the first heat dissipation substrate and the second heat dissipation substrate are mainly made of aluminum or copper.

11. The first heat dissipation substrate and the second heat dissipation substrate are Each of the insulating and heat-dissipating sheets is connected to the opposing surface of the other. The insulating and heat-dissipating sheet is an insulating layer; The semiconductor device according to claim 1 , further comprising a metal layer stacked on the insulating layer.

12. The semiconductor device according to claim 11 , further comprising a cooler connected to said first heat dissipation substrate or said second heat dissipation substrate via said insulating heat dissipation sheet.

13. 5. The semiconductor device according to claim 1, further comprising a cooler connected to the first heat dissipation substrate or the second heat dissipation substrate.

14. The semiconductor device according to claim 1 , further comprising a sealing resin that covers the semiconductor element, the first heat dissipation substrate, and the second heat dissipation substrate.

15. 5. The semiconductor device according to claim 1, wherein the semiconductor element is an insulated gate bipolar transistor.

16. The semiconductor device according to claim 1 , wherein the semiconductor element includes a wide bandgap semiconductor.

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

18. preparing a semiconductor element having a first heat dissipation substrate, a second heat dissipation substrate, a heat dissipation block, a terminal with a first through hole formed therein, and an electrode; mounting the semiconductor element on the first heat dissipation substrate via a first bonding material; a step of heating the first bonding material to bond the semiconductor element to the first heat dissipation substrate via the first bonding material; The heat dissipation block is mounted on the electrode of the semiconductor element via a second bonding material, and the terminal with the heat dissipation block disposed inside the first through hole is mounted thereon; and mounting a second heat dissipation substrate on the heat dissipation block via a third bonding material; and heating the second bonding material and the third bonding material so that the second bonding material and the third bonding material cover the side surfaces of the heat dissipation block and bond the electrodes, the second heat dissipation substrate, and the terminals.

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