Semiconductor device and power conversion device

Abstract

To provide a technique capable of relaxing a stress to an insulation member and improving reliability in a semiconductor device.SOLUTION: A semiconductor device 50 comprises an insulation layer 3, a circuit pattern 4 provided on an upper surface of the insulation layer 3, a semiconductor element 5 joined to an upper surface of the circuit pattern 4 by a first joining material 7a, an insulation member 6 joined to the upper surface of the circuit pattern 4 by a second joining material 7b, and a lead electrode 9 connecting the semiconductor element 5 and the insulation member 6. An upper surface of the semiconductor element 5 and a lower surface of the lead electrode 9 are joined by a third joining member 7c, and an upper surface of the insulation member 6 and the lower surface of the lead electrode 9 are joined by a fourth joining member 7d. The first joining member 7a, the second joining member 7b, the third joining member 7c, and the fourth joining member 7d are made of the same material.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] As the current capacity of semiconductor devices increases, there is a demand for improving the heat dissipation properties of the semiconductor elements and lead electrodes included in the semiconductor devices.

[0003] For example, Patent Document 1 discloses a semiconductor device including a semiconductor element, a lead electrode having one end connected to the upper surface of the semiconductor element, a cooling mechanism disposed on the lower surface side of the semiconductor element via a heat spreader, and a heat dissipation block disposed thermally coupled between the lower surface of the other end side of the lead electrode and the cooling mechanism. This improves the heat dissipation of the semiconductor element and the lead electrode without increasing the product size. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2017 / 130370 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the technology described in Patent Document 1, if there is even a slight deviation in the height dimension of the heat dissipation block from the combined height dimension of the semiconductor element, solder, heat spreader, and lead electrodes, the relatively more easily deformed members will deform. If the insulating layer provided under the heat dissipation block deforms and dielectric breakdown occurs, it will lead to malfunction of the semiconductor device.

[0006] In view of the above, an object of the present disclosure is to provide a technique capable of alleviating stress on insulating members in semiconductor devices and improving reliability. [Means for solving the problem]

[0007] A semiconductor device according to the present disclosure includes an insulating layer, a circuit pattern provided on an upper surface of the insulating layer, a semiconductor element bonded to the upper surface of the circuit pattern with a first bonding material, an insulating member bonded to the upper surface of the circuit pattern with a second bonding material, and lead electrodes connecting the semiconductor element and the insulating member. a second insulating layer different from the first insulating layer; and a second circuit pattern different from the first circuit pattern provided on a lower surface of the second insulating layer. an upper surface of the semiconductor element and a lower surface of the lead electrode are joined by a third joining material, an upper surface of the insulating member and a lower surface of the lead electrode are joined by a fourth joining material, and the first joining material, the second joining material, the third joining material, and the fourth joining material are made of the same material. the separate circuit pattern is provided on the upper side of the lead electrode, and the upper surface of the lead electrode at the portion where the semiconductor element and the insulating member are joined is joined to the separate circuit pattern by a fifth joining material and a sixth joining material, respectively, and the first joining material, the second joining material, the third joining material, the fourth joining material, the fifth joining material, and the sixth joining material are made of the same material. It is something. Effect of the Invention

[0008] According to the present disclosure, stress on the insulating member can be alleviated by adjusting the thicknesses of the second bonding material for bonding the insulating member to the upper surface of the circuit pattern and the fourth bonding material for bonding the upper surface of the insulating member to the lower surface of the lead electrode.

[0009] Furthermore, since the first bonding material, the second bonding material, the third bonding material, and the fourth bonding material are made of the same material, the number of heating cycles required for bonding can be reduced, and therefore thermal deterioration of each member of the semiconductor device can be suppressed. As a result, the reliability of the semiconductor device can be improved. [Brief description of the drawings]

[0010] [Figure 1] 1 is a schematic cross-sectional view of a semiconductor device according to a first embodiment. [Diagram 2] 2 is a schematic top view of a lead electrode included in the semiconductor device according to the first embodiment, viewed from above. FIG. [Diagram 3] FIG. 11 is a schematic cross-sectional view of a semiconductor device according to a second embodiment. [Figure 4] 13 is a schematic top view of a lead electrode included in a semiconductor device according to a first modification of the second embodiment, viewed from above. FIG. [Diagram 5]FIG. 13 is a schematic cross-sectional view of a semiconductor device according to Modification 2 of the second embodiment. [Figure 6] FIG. 13 is a circuit diagram showing a configuration of a semiconductor device according to a third modification of the second embodiment. [Figure 7] FIG. 13 is a circuit diagram showing a configuration of a semiconductor device according to a fourth modification of the second embodiment. [Figure 8] FIG. 11 is a schematic cross-sectional view of a semiconductor device according to a fifth modification of the second embodiment. [Figure 9] 13 is a top view of a lead electrode included in a semiconductor device according to a sixth modification of the second embodiment. FIG. [Figure 10] FIG. 11 is a schematic cross-sectional view of a semiconductor device according to a third embodiment. [Figure 11] FIG. 11 is a schematic cross-sectional view of a semiconductor device according to a fourth embodiment. [Figure 12] FIG. 13 is a schematic cross-sectional view of a semiconductor device according to a fifth embodiment. [Figure 13] 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 PREFERRED EMBODIMENTS

[0011] <Embodiment 1> <Configuration of Semiconductor Device> The first embodiment will be described below with reference to the drawings. Fig. 1 is a schematic cross-sectional view of a semiconductor device 50 according to the first embodiment. Fig. 2 is a schematic top view of a lead electrode 9 included in the semiconductor device 50 according to the first embodiment, viewed from above.

[0012] As shown in FIG. 1, a semiconductor device 50 includes a cooling mechanism 1, a metal pattern 2, an insulating layer 3, a circuit pattern 4, a semiconductor element 5, an insulating member 6, lead electrodes 8 and 9, and a sealing resin .

[0013] The cooling mechanism 1 is a structure made mainly of Al or Cu, has an internal fin structure, and has a water-cooling function.

[0014] The metal pattern 2 is provided on the upper surface of the cooling mechanism 1 via thermal grease (not shown). The metal pattern 2 is mainly made of copper. By using a material with high thermal conductivity for the metal pattern 2, the heat generated by the semiconductor element 5 can be effectively diffused, and the life of the semiconductor device 50 can be improved.

[0015] The insulating layer 3 is provided on the upper surface of the metal pattern 2. The insulating layer 3 is mainly composed of AlN, Al2O3, or SiN. A circuit pattern 4 is provided on the upper surface of the insulating layer 3. By using a material with high thermal conductivity for the insulating layer 3, heat dissipation from the circuit pattern 4 to the metal pattern 2 via the insulating layer 3 is improved, so that a temperature rise in the semiconductor element 5 can be suppressed and the life of the semiconductor device 50 can be improved.

[0016] Furthermore, the insulating layer 3 may be mainly made of a resin having a thermal conductivity of 10 W / m·K or more. By using a material with high thermal conductivity and high resistance to deformation as the insulating layer 3, the occurrence of cracks when minute deformation occurs in the members inside the semiconductor device 50 due to a heat cycle or the like is suppressed, so that the semiconductor device 50 can achieve both high heat dissipation and high reliability. Moreover, it is inexpensive.

[0017] An internal connection portion 8a of a lead electrode 8, a semiconductor element 5, and an insulating member 6 are bonded to the upper surface of the circuit pattern 4. The internal connection portion 8a of the lead electrode 8 is bonded to the upper surface of the circuit pattern 4 by a bonding material 7. The semiconductor element 5 is bonded to the upper surface of the circuit pattern 4 by a first bonding material 7a. The insulating member 6 is bonded to the upper surface of the circuit pattern 4 by a second bonding material 7b. A lead electrode 9 connecting the semiconductor element 5 and the insulating member 6 is bonded to the upper surfaces of the semiconductor element 5 and the insulating member 6 by a third bonding material 7c and a fourth bonding material 7d, respectively.

[0018] In this manner, the second bonding material 7b and the fourth bonding material 7d are disposed on the lower surface and the upper surface, respectively, of the insulating member 6. The thicknesses of the second bonding material 7b and the fourth bonding material 7d are adjustable, and by adjusting the second bonding material 7b and the fourth bonding material 7d to an appropriate thickness, the second bonding material 7b and the fourth bonding material 7d can serve as a buffer material for the insulating member 6. This allows the stress on the insulating member 6 to be alleviated.

[0019] The insulating member 6 is located between the portion of the internal connection portion 9a of the lead electrode 9 where the semiconductor element 5 is joined and the external connection portion 9b. The portion of the internal connection portion 9a of the lead electrode 9 where the insulating member 6 is joined is recessed downward, and the other portions of the lead electrode 9 are flat. Heat generated by the semiconductor element 5 is dissipated from the lower surface of the semiconductor element 5 to the circuit pattern 4, and is also conducted from the upper surface of the semiconductor element 5 to the lead electrode 9, and is dissipated from the lead electrode 9 to the circuit pattern 4 via the insulating member 6, so that a rise in temperature of the semiconductor element 5 and the lead electrode 9 can be suppressed.

[0020] The insulating member 6 is mainly made of Si, AlN, Al2O3, SiN having an oxide film, or a resin having a higher thermal conductivity than the sealing resin 10. By using a material with high thermal conductivity for the insulating member 6, heat from the lead electrodes 9 is efficiently transferred to the cooling mechanism 1 via the insulating member 6, so that the temperature rise of the semiconductor element 5 and the lead electrodes 9 can be suppressed and the life and temperature characteristics of the semiconductor device 50 can be improved.

[0021] The first bonding material 7a, the second bonding material 7b, the third bonding material 7c, and the fourth bonding material 7d are made of the same material, and the number of heating times required for bonding can be reduced, so that the thermal deterioration of each member included in the semiconductor device 50 can be suppressed. Specifically, solder or silver is adopted for the first bonding material 7a, the second bonding material 7b, the third bonding material 7c, and the fourth bonding material 7d. By adopting bonding materials with high thermal conductivity as the first bonding material 7a, the second bonding material 7b, the third bonding material 7c, and the fourth bonding material 7d, it is possible to effectively diffuse heat to the upper and lower surfaces of the semiconductor element 5, and to diffuse heat from the lead electrode 9 to the cooling mechanism 1 via the insulating member 6. This suppresses the temperature rise of the semiconductor element 5 and the lead electrode 9, and improves the life and temperature characteristics of the semiconductor device 50. The bonding material 7 is also made of the same material as the first bonding material 7a, the second bonding material 7b, the third bonding material 7c, and the fourth bonding material 7d.

[0022] The lead electrodes 8 and 9 are mainly made of copper. 8, By using a material with high thermal conductivity as the material 9, the heat generated in the semiconductor element 5 can be effectively diffused, leading to stabilization of the quality of the semiconductor device 50.

[0023] The cross-sectional area of ​​the lead electrode 9 is 50 The resistance R1 of the semiconductor element 5 and the resistance R2 of the lead electrode 9 are set to a value such that the heat generation temperature due to the conductor resistance of the lead electrode 9 is smaller than the heat generation temperature of the semiconductor element 5 when the semiconductor element 5 is driven. This will be explained below. If the heat generation temperature of the semiconductor element 5 is T1 and the heat generation temperature of the lead electrode 9 is T2, by making T1 > T2, the heat generated in the semiconductor element 5 is dissipated to the cooling mechanism 1 via the lead electrode 9 and the insulating member 6. In order for T1 > T2 to be satisfied, the relationship between the resistance value R1 of the semiconductor element 5 and the resistance value R2 of the lead electrode 9 needs to be R1 > R2. R2 is the resistance of the lead electrode 9. resistivity If T1 is ρ, the length of lead electrode 9 is L, and the cross-sectional area of ​​lead electrode 9 is A, then R2 = ρ × L / A. Therefore, by setting the cross-sectional area A of lead electrode 9 to a large value, R1>R2, that is, T1>T2, is satisfied.

[0024] As described above, by setting the cross-sectional area A of the lead electrode 9 large, the heat generated in the semiconductor element 5 is dissipated to the cooling mechanism 1 via the lead electrode 9 and the insulating member 6, thereby lowering the temperature of the semiconductor element 5, and therefore lowering the maximum temperature of the semiconductor device 50, leading to an improvement in the life span and stable operation of the semiconductor device 50.

[0025] Moreover, the width of the lead electrode 9 does not have to be constant. By making the width of the current path in the lead electrode 9 larger than the width of other parts, the current density can be reduced, and the amount of heat generated by the resistance of the lead electrode 9 can be suppressed. This makes it possible to suppress a temperature rise in the semiconductor device 50.

[0026] A reverse conducting IGBT (RC-IGBT) is used as the semiconductor element 5. This allows the area of ​​the semiconductor element 5 to be reduced, making it possible to miniaturize the semiconductor device 50. Furthermore, the reverse conducting IGBT is always in a conducting state and is therefore more likely to become hot than a case in which an IGBT chip and a Diode chip are mounted separately. However, by adopting the structure of the first embodiment, heat can be dissipated from the top surface of the semiconductor element 5 via the lead electrodes 9, making it possible to suppress temperature rise and ensure stable operation in the semiconductor device 50.

[0027] Moreover, SiC is adopted as the semiconductor material of the semiconductor element 5. By adopting the low-loss semiconductor element 5, heat generation of the semiconductor element 5 can be suppressed, so that the maximum temperature in the semiconductor device 50 can be lowered and the life of the semiconductor device 50 can be improved. Furthermore, the amount of power used in the semiconductor device 50 can be reduced, which enables energy saving.

[0028] The sealing resin 10 is an epoxy resin or gel, and seals the metal pattern 2 except for its underside, the insulating layer 3, the circuit pattern 4, the internal connections 8a, 9a of the lead electrodes 8, 9, the semiconductor element 5, and the insulating member 6, and the external connections 8b, 9b of the lead electrodes 8, 9 protrude from the sealing resin 10.

[0029] 2, consider a case where two circuit patterns 4 are provided in parallel, and a lead electrode 12 is provided in parallel to the lead electrode 8 on a circuit pattern 4 other than the circuit pattern 4 on which the lead electrode 8 is provided. The sealing resin 10 can shorten the insulation distance between the two circuit patterns 4 and between the lead electrode 8 and the lead electrode 12, making it possible to miniaturize the semiconductor device 50. The sealing resin 10 also serves to protect the semiconductor element 5, and can reduce external impacts on the semiconductor element 5 and improve the life of the semiconductor device 50.

[0030] <Effects> As described above, the semiconductor device 50 of embodiment 1 comprises an insulating layer 3, a circuit pattern 4 provided on the upper surface of the insulating layer 3, a semiconductor element 5 joined to the upper surface of the circuit pattern 4 with a first bonding material 7a, an insulating member 6 joined to the upper surface of the circuit pattern 4 with a second bonding material 7b, and a lead electrode 9 connecting the semiconductor element 5 and the insulating member 6, wherein the upper surface of the semiconductor element 5 and the lower surface of the lead electrode 9 are joined with a third bonding material 7c, and the upper surface of the insulating member 6 and the lower surface of the lead electrode 9 are joined with a fourth bonding material 7d, with the first bonding material 7a, the second bonding material 7b, the third bonding material 7c, and the fourth bonding material 7d being made of the same material.

[0031] Therefore, by adjusting the thickness of the second bonding material 7b for bonding the insulating member 6 to the upper surface of the circuit pattern 4 and the fourth bonding material 7d for bonding the upper surface of the insulating member 6 to the lower surface of the lead electrode 9, the stress on the insulating member 6 can be alleviated.

[0032] Furthermore, the first bonding material 7a, the second bonding material 7b, the third bonding material 7c, and the fourth bonding material 7d are made of the same material, and the number of heating cycles required for bonding can be reduced, thereby suppressing thermal deterioration of each member included in the semiconductor device 50. As a result, the reliability of the semiconductor device 50 can be improved.

[0033] Furthermore, the lead electrode 9 has an external connection portion 9b that can be connected to an external device, and the insulating member 6 is located between the portion of the lead electrode 9 to which the semiconductor element 5 is joined and the external connection portion 9b. Therefore, heat generated by the semiconductor element 5 is dissipated to the circuit pattern 4 via the insulating member 6, so that a rise in temperature of the semiconductor element 5 and the lead electrode 9 can be suppressed.

[0034] The semiconductor device 50 further includes a sealing resin 10 that seals a part of the lead electrode 9, the semiconductor element 5, and the insulating member 6, and the sealing resin 10 contains an epoxy resin or gel. Therefore, the insulation distance between the circuit pattern 4 and the lead electrode 9 in the semiconductor device 50 can be shortened, and the semiconductor device 50 can be made smaller. The sealing resin 10 also serves to protect the semiconductor element 5, and therefore can reduce external impacts on the semiconductor element 5 and improve the life of the semiconductor device 50.

[0035] Furthermore, the insulating member 6 contains Si, AlN, Al2O3, SiN having an oxide film, or a resin having a higher thermal conductivity than the sealing resin 10. Therefore, the heat of the lead electrode 9 is efficiently transferred to the cooling mechanism 1 via the insulating member 6, so that the temperature rise of the semiconductor element 5 and the lead electrode 9 can be suppressed, and the life and temperature characteristics of the semiconductor device 50 can be improved.

[0036] Furthermore, since the lead electrodes 9 contain copper, the heat generated in the semiconductor element 5 can be effectively diffused, which leads to stabilization of the quality of the semiconductor device 50.

[0037] In addition, since the first bonding material 7a contains solder or silver, the second bonding material 7b, the third bonding material 7c, and the fourth bonding material 7d also contain solder or silver. This allows effective heat diffusion to the upper and lower surfaces of the semiconductor element 5 and from the lead electrodes 9 to the cooling mechanism 1 via the insulating member 6, thereby suppressing temperature rises in the semiconductor element 5 and the lead electrodes 9 and improving the life and temperature characteristics of the semiconductor device 50.

[0038] Furthermore, the cross-sectional area of ​​the lead electrodes 9 is set to a size such that the heat temperature due to the conductor resistance of the lead electrodes 9 is smaller than the heat temperature of the semiconductor element 5 when the semiconductor device 50 is operating. Therefore, the heat of the semiconductor element 5 is transferred to the lead electrodes 9, lowering the temperature of the semiconductor element 5. This lowers the maximum temperature of the semiconductor device 50, leading to an improvement in the life span and stable operation of the semiconductor device 50.

[0039] Moreover, the insulating layer 3 contains AlN, Al2O3, or SiN. Therefore, by adopting an insulating layer with high thermal conductivity as the insulating layer 3, it is possible to improve the heat dissipation from the circuit pattern 4 to the metal pattern 2, thereby suppressing the temperature rise of the semiconductor device 50 and improving the life of the semiconductor device 50.

[0040] Furthermore, insulating layer 3 contains a resin having a thermal conductivity of 10 W / m·K or more. Therefore, by using an insulating layer made of a resin having high thermal conductivity and high resistance to deformation as insulating layer 3, it is possible to suppress the occurrence of cracks when minute deformation occurs in members within semiconductor device 50 due to a heat cycle or the like, and therefore semiconductor device 50 can achieve both high heat dissipation and high reliability.

[0041] Moreover, the semiconductor device 50 further includes a metal pattern 2 provided on the lower surface of the insulating layer 3, and the metal pattern 2 contains copper. Therefore, by using a material with high thermal conductivity as the metal pattern 2, the heat generated by the semiconductor element 5 can be effectively diffused, and the life of the semiconductor device 50 can be improved.

[0042] In addition, since the width of the lead electrode 9 is not constant, the current density can be reduced by making the width of the current path in the lead electrode 9 larger than other parts. This makes it possible to suppress the amount of heat generated by the conductor resistance of the lead electrode 9, thereby suppressing the temperature rise of the semiconductor device 50.

[0043] Furthermore, since the semiconductor element 5 is a reverse conducting IGBT, the area of ​​the semiconductor element 5 can be reduced, enabling the semiconductor device 50 to be miniaturized. A reverse conducting IGBT is always in a conducting state, and is therefore more likely to become hot than a case in which an IGBT chip and a Diode chip are mounted separately. However, since heat can be dissipated from the top surface of the semiconductor element 5 via the lead electrodes 9, the temperature rise of the semiconductor device 50 is suppressed, enabling stable operation.

[0044] Moreover, since the semiconductor material of the semiconductor element 5 is SiC, heat generation from the semiconductor element 5 can be suppressed, and the maximum temperature inside the semiconductor device 50 can be reduced, thereby improving the life of the semiconductor device 50. Furthermore, the amount of power used in the semiconductor device 50 can be reduced, enabling energy conservation.

[0045] <Embodiment 2> Next, a semiconductor device 50A according to embodiment 2 will be described. Fig. 3 is a schematic cross-sectional view of the semiconductor device 50A according to embodiment 2. Note that in embodiment 2, the same components as those described in embodiment 1 are denoted by the same reference numerals and the description thereof will be omitted.

[0046] 3, in the second embodiment, the shape of the lead electrode 9 is different from that in the first embodiment. Specifically, in the first embodiment, the portion of the lead electrode 9 where the insulating member 6 is joined is recessed downward, but in the second embodiment, the entire lead electrode 9 is formed in a flat plate shape.

[0047] As described above, in the semiconductor device 50A according to the second embodiment, the lead electrode 9 is formed in a flat plate shape. In the first embodiment, stress may be applied to the insulating member 6 due to processing errors during bending, but by forming the lead electrode 9 in a flat plate shape as in the second embodiment, processing errors are eliminated, and stress to the insulating member 6 can be suppressed.

[0048] <Modification of the second embodiment> Next, a modification of the second embodiment will be described. FIG. 4 is a schematic top view of the lead electrode 9 included in the semiconductor device 50A according to the first modification of the second embodiment, viewed from above. FIG. 5 is a schematic cross-sectional view of the semiconductor device 50A according to the second modification of the second embodiment. FIG. 6 is a circuit diagram showing a configuration of the semiconductor device 50A according to the third modification of the second embodiment. FIG. 7 is a circuit diagram showing a configuration of the semiconductor device 50A according to the fourth modification of the second embodiment. FIG. 8 is a schematic cross-sectional view of the semiconductor device 50A according to the fifth modification of the second embodiment. FIG. 9(a) is a top view showing an example of the lead electrode 9 included in the semiconductor device 50A according to the sixth modification of the second embodiment. FIG. 9(b) is a top view showing another example of the lead electrode 9 included in the semiconductor device 50A according to the sixth modification of the second embodiment.

[0049] 4, a first joint portion of the lead electrode 9 to which the semiconductor element 5 is joined and a second joint portion of the lead electrode 9 to which the insulating member 6 is joined may have through holes 9c and 9d having diameters smaller than those of the first and second joint portions. The third and fourth bonding materials 7c and 7d are disposed in the through holes 9c and 9d, respectively, so that the third and fourth bonding materials 7c and 7d are prevented from spreading to areas other than the joint portions, and electrical continuity is prevented in areas other than where connection is required. This improves the reliability of the semiconductor device 50A.

[0050] 5, the semiconductor device 50A may include a plurality of (for example, two) semiconductor elements 5. This makes it possible to increase the voltage that can be applied to the semiconductor device 50A and the amount of current that can be passed through the semiconductor device 50A, thereby enabling the semiconductor device 50A to have a higher output.

[0051] 6 and 7, a plurality of semiconductor elements 5 may be arranged in parallel. A combination of an IGBT and an FWD is used as the semiconductor element 5. For example, when heat generation between a collector 1 and an emitter 1 is considered, as shown in FIG. Only Rather than driving IGBT1, FWD1, IGBT2, and FWD2, as shown in Figure 7, ofDrive do This allows heat generation locations to be dispersed, making it possible to suppress the maximum temperature inside the semiconductor device 50 and enabling the semiconductor device 50 to operate stably.

[0052] 8, the semiconductor device 50A may include a plurality of (for example, two) insulating members 6. Since heat generated by the semiconductor element 5 is dissipated to the cooling mechanism 1 via the lead electrodes 9 and the insulating members 6, providing a plurality of insulating members 6 can improve the heat dissipation and life span of the semiconductor device 50A.

[0053] Furthermore, as shown in Figures 9(a) and (b), a roughened portion 11 having a rougher surface than the areas other than the outer periphery of the through holes 9c and 9d in the lead electrode 9 may be formed on the outer periphery of the through holes 9c and 9d in the lead electrode 9.

[0054] More specifically, as shown in FIG. 9(a), a circular roughened portion 11 may be formed along the outer periphery of the through holes 9c, 9d on the underside of the lead electrode 9, or as shown in FIG. 9(b), a rectangular roughened portion 11 may be formed including the outer periphery of the through holes 9c, 9d on the underside of the lead electrode 9.

[0055] If the fourth bonding material 7d on the upper surface of the insulating member 6 spreads excessively, contact with the second bonding material 7b on the lower surface of the insulating member 6 will result in a loss of insulation provided by the insulating member 6. By forming the roughened portion 11 on the outer periphery of the through holes 9c, 9d on the lower surface of the lead electrode 9, it is possible to suppress the fourth bonding material 7d from spreading excessively and improve the insulation provided by the insulating member 6.

[0056] The content of the modified example of the second embodiment can also be combined with other embodiments.

[0057] <Embodiment 3> Next, a semiconductor device 50B according to an embodiment 3 will be described. Fig. 10 is a schematic cross-sectional view of the semiconductor device 50B according to the embodiment 3. In the embodiment 3, the same components as those described in the embodiments 1 and 2 are denoted by the same reference numerals, and the description thereof will be omitted.

[0058] 10, in the third embodiment, a semiconductor device 50B includes a plurality of (for example, two) structures each including a metal pattern 2, an insulating layer 3, and a circuit pattern 4, and a semiconductor element 5 and an insulating member 6 are bonded to the upper surfaces of different circuit patterns 4. The structure of the third embodiment can be combined with other embodiments.

[0059] As described above, the semiconductor device 50B according to the third embodiment includes a plurality of circuit patterns 4, and the semiconductor element 5 and the insulating member 6 are bonded to the upper surfaces of different circuit patterns 4. This eliminates interference of heat transferred to each circuit pattern 4, thereby improving the heat dissipation performance of the semiconductor device 50B.

[0060] <Fourth embodiment> Next, a semiconductor device 50C according to an embodiment 4 will be described. Fig. 11 is a schematic cross-sectional view of the semiconductor device 50C according to the embodiment 4. Note that in the embodiment 4, the same components as those described in the embodiments 1 to 3 are denoted by the same reference numerals and the description thereof will be omitted.

[0061] 11, in the fourth embodiment, the insulating member 6 is bonded by a second bonding material 7b to the upper surface of the cooling mechanism 1, not to the upper surface of the circuit pattern 4. Also, the portion of the internal connection portion 9a of the lead electrode 9 where the insulating member 6 is bonded is recessed downward, and the other portions of the lead electrode 9 are flat.

[0062] As described above, the semiconductor device 50C of embodiment 4 comprises a cooling mechanism 1, an insulating layer 3 provided on the upper surface of the insulating layer 3, a semiconductor element 5 joined to the upper surface of the circuit pattern 4 by a first bonding material 7a, an insulating member 6 joined to the upper surface of the cooling mechanism 1 by a second bonding material 7b, and a lead electrode 9 connecting the semiconductor element 5 and the insulating member 6, wherein the upper surface of the semiconductor element 5 and the lower surface of the lead electrode 9 are joined by a third bonding material 7c, and the upper surface of the insulating member 6 and the lower surface of the lead electrode 9 are joined by a fourth bonding material 7d, and the first bonding material 7a, the second bonding material 7b, the third bonding material 7c, and the fourth bonding material 7d are made of the same material.

[0063] Therefore, heat generated by the semiconductor element 5 can be dissipated directly to the cooling mechanism 1 without passing through the insulating layer 3, so that the temperature rise of the semiconductor device 50C can be further suppressed.

[0064] <Fifth Preferred Embodiment> Next, a semiconductor device 50D according to an embodiment 5 will be described. Fig. 12 is a schematic cross-sectional view of the semiconductor device 50D according to the embodiment 5. Note that in the embodiment 5, the same components as those described in the embodiments 1 to 4 are denoted by the same reference numerals, and the description thereof will be omitted.

[0065] As shown in FIG. 12, in the fifth embodiment, in addition to the structure of the second embodiment, a circuit pattern 24, an insulating layer 23, a metal pattern 22, and a cooling mechanism 21 are further provided above the lead electrode 9.

[0066] The upper surface of the lead electrode 9 at the portion where the semiconductor element 5 and the insulating member 6 are bonded is bonded to the lower surface of the circuit pattern 24 by a fifth bonding material 7e and a sixth bonding material 7f, respectively. The fifth bonding material 7e and the sixth bonding material 7f are made of the same material as the first bonding material 7a, the second bonding material 7b, the third bonding material 7c, and the fourth bonding material 7d.

[0067] As described above, the semiconductor device 50D of embodiment 5 further includes another insulating layer 23 different from the insulating layer 3, and another circuit pattern 24 different from the circuit pattern 4 provided on the lower surface of the other insulating layer 23, the other circuit pattern 24 being provided on the upper side of the lead electrode 9, and the upper surface of the lead electrode 9 at which the semiconductor element 5 and the insulating member 6 are joined is joined to the other circuit pattern 24 by the fifth bonding material 7e and the sixth bonding material 7f, respectively, and the first bonding material 7a, the second bonding material 7b, the third bonding material 7c, the fourth bonding material 7d, the fifth bonding material 7e, and the sixth bonding material 7f are made of the same material.

[0068] Therefore, heat generated by the semiconductor element 5 spreads to the upper side of the lead electrodes 9 via the lead electrodes 9, thereby further improving the heat dissipation performance of the semiconductor device 50D. This further suppresses the temperature rise of the semiconductor device 50D, thereby improving the life of the semiconductor device 50D.

[0069] <Sixth embodiment> In this embodiment, the semiconductor devices 50 to 50D according to the above-mentioned embodiments 1 to 5 are applied to a power conversion device. Although the application of the semiconductor devices 50 to 50D according to the embodiments 1 to 5 is not limited to a specific power conversion device, a case in which the semiconductor devices 50 to 50D according to the embodiments 1 to 5 are applied to a three-phase inverter will be described below as embodiment 6.

[0070] FIG. 13 is a block diagram showing a configuration of a power conversion system to which a power conversion device 200 according to the sixth embodiment is applied.

[0071] The power conversion system shown in Fig. 13 is composed of a power source 100, a power conversion device 200, and a load 300. The power source 100 is a DC power source and supplies DC power to the power conversion device 200. The power source 100 can be composed of various things, for example, 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 100 may also be composed of a DC / DC converter that converts DC power output from a DC system into a predetermined power.

[0072] The power conversion device 200 is a three-phase inverter connected between the power source 100 and the load 300, converts DC power supplied from the power source 100 into AC power, and supplies the AC power to the load 300. As shown in Fig. 13, the power conversion device 200 includes a main conversion circuit 201 that converts DC power into AC power and outputs it, a drive circuit 202 that outputs drive signals that drive each switching element of the main conversion circuit 201, and a control circuit 203 that outputs a control signal for controlling the drive circuit 202 to the drive circuit 202.

[0073] The load 300 is a three-phase motor driven by AC power supplied from the power conversion device 200. The load 300 is not limited to a specific use, but is a motor mounted on various electric devices, and is used as, for example, a motor for a hybrid car, an electric car, a railroad car, an elevator, or an air conditioner.

[0074] The power conversion device 200 will be described in detail below. The main conversion circuit 201 includes switching elements and free wheel diodes (not shown), and converts DC power supplied from the power source 100 into AC power by switching the switching elements, and supplies the AC power to the load 300. There are various specific circuit configurations of the main conversion circuit 201, but the main conversion circuit 201 according to this embodiment is a two-level three-phase full bridge circuit, and can be configured with six switching elements and six free wheel diodes connected in reverse parallel to each switching element. The semiconductor devices 50 to 50D according to the above-mentioned first to fifth embodiments are applied to each switching element of the main conversion circuit 201. Two switching elements of the six switching elements are connected in series to configure upper and lower arms, and each upper and lower arm configures each 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 201, are connected to the load 300.

[0075] The drive circuit 202 generates drive signals for driving the switching elements of the main conversion circuit 201 and supplies them to the control electrodes of the switching elements of the main conversion circuit 201. Specifically, in accordance with a control signal from a control circuit 203 described later, the drive circuit 202 outputs to the control electrodes of each switching element a drive signal for turning the switching element on and a drive signal for turning the switching element off. When maintaining a switching element in the on state, the drive signal is a voltage signal (on signal) 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) equal to or lower than the threshold voltage of the switching element.

[0076] The control circuit 203 controls the switching elements of the main conversion circuit 201 so that a desired power is supplied to the load 300. Specifically, the control circuit 203 calculates the time (on time) for each switching element of the main conversion circuit 201 to be in the on state based on the power to be supplied to the load 300. For example, the main conversion circuit 201 can be controlled by PWM control that modulates the on time of the switching elements according to the voltage to be output. Then, the control circuit 203 outputs a control command (control signal) to the drive circuit 202 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. The drive circuit 202 outputs an on signal or an off signal as a drive signal to the control electrode of each switching element according to this control signal.

[0077] In the power conversion device 200 according to the present embodiment, the semiconductor devices 50-50D according to the first to fifth embodiments are applied as switching elements of the main conversion circuit 201, and therefore the stress on the insulating layer 3 arranged under the insulating member 6 can be alleviated, thereby improving the reliability of the semiconductor devices 50-50D. This improves the reliability of the power conversion device 200.

[0078] In the present embodiment, an example in which the semiconductor devices 50 to 50D according to the first to fifth embodiments are applied to a two-level three-phase inverter has been described, but the application of the semiconductor devices 50 to 50D according to the first to fifth embodiments is not limited to this, and they can be applied to various power conversion devices. In the present embodiment, a two-level power conversion device is described, but a three-level or multi-level power conversion device may be used, and when power is supplied to a single-phase load, the semiconductor devices 50 to 50D according to the first to fifth embodiments may be applied to a single-phase inverter. Furthermore, when power is supplied to a DC load or the like, the semiconductor devices 50 to 50D according to the first to fifth embodiments can also be applied to a DC / DC converter or an AC / DC converter.

[0079] Furthermore, the power conversion device to which the semiconductor devices 50 to 50D according to embodiments 1 to 5 are applied is not limited to the case where the load described above 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 non-contact power supply system, and can also be used as a power conditioner for a solar power generation system, a power storage system, etc.

[0080] It should be noted that the embodiments can be freely combined, and each embodiment can be modified or omitted as appropriate. [Explanation of symbols]

[0081] REFERENCE SIGNS LIST 1 Cooling mechanism, 2 Metal pattern, 3 Insulating layer, 4 Circuit pattern, 5 Semiconductor element, 6 Insulating member, 7a First bonding material, 7b Second bonding material, 7c Third bonding material, 7d Fourth bonding material, 7e Fifth bonding material, 7f Sixth bonding material, 9 Lead electrode, 9b External connection portion, 9c, 9d Through hole, 10 Sealing resin, 11 Roughened portion, 23 Insulating layer, 24 Circuit pattern, 50, 50A, 50B, 50C, 50D Semiconductor device, 200 Power conversion device, 201 Main conversion circuit, 203 Control circuit.

Claims

1. An insulating layer; A circuit pattern provided on an upper surface of the insulating layer; a semiconductor element bonded to an upper surface of the circuit pattern by a first bonding material; an insulating member bonded to an upper surface of the circuit pattern by a second bonding material; a lead electrode connecting the semiconductor element and the insulating member; Another insulating layer different from the insulating layer; and a circuit pattern different from the circuit pattern and provided on a lower surface of the other insulating layer, an upper surface of the semiconductor element and a lower surface of the lead electrode are joined by a third joining material; an upper surface of the insulating member and a lower surface of the lead electrode are joined by a fourth joining material; the first bonding material, the second bonding material, the third bonding material, and the fourth bonding material are made of the same material; the other circuit pattern is provided on an upper side of the lead electrode, an upper surface of the lead electrode at a portion where the semiconductor element and the insulating member are bonded is bonded to the separate circuit pattern by a fifth bonding material and a sixth bonding material, respectively; A semiconductor device, wherein the first bonding material, the second bonding material, the third bonding material, the fourth bonding material, the fifth bonding material, and the sixth bonding material are made of the same material.

2. the lead electrode has an external connection portion that can be connected to an external device; 2. The semiconductor device according to claim 1, wherein the insulating member is located between the portion of the lead electrode to which the semiconductor element is joined and the external connection portion.

3. a sealing resin that seals a portion of the lead electrode, the semiconductor element, and the insulating member; 3. The semiconductor device according to claim 1, wherein the sealing resin includes an epoxy resin or a gel.

4. The insulating member is made of Si, AlN, or Al having an oxide film. 2 O 3 4. The semiconductor device according to claim 3, further comprising: SiN or a resin having a higher thermal conductivity than the sealing resin.

5. The semiconductor device according to claim 1 , wherein the lead electrodes contain copper.

6. The semiconductor device according to claim 1 , wherein the first bonding material contains solder or silver.

7. 7. The semiconductor device according to claim 1, wherein a cross-sectional area of ​​the lead electrode is set to a size such that a heat generation temperature due to a conductor resistance of the lead electrode is smaller than a heat generation temperature of the semiconductor element when the semiconductor device is operated.

8. The insulating layer is made of AlN, Al 2 O 3 The semiconductor device according to claim 1 , further comprising: a SiO 2 layer; or SiN.

9. The semiconductor device according to claim 1 , wherein the insulating layer contains a resin having a thermal conductivity of 10 W / m·K or more.

10. Further comprising a metal pattern provided on a lower surface of the insulating layer, The semiconductor device according to claim 1 , wherein the metal pattern contains copper.

11. 2. The semiconductor device according to claim 1, wherein said lead electrodes are formed in a flat plate shape.

12. 12. The semiconductor device according to claim 1, wherein a through hole having a diameter smaller than that of the first joint and the second joint is formed at a first joint portion of the lead electrode to which the semiconductor element is joined, and at a second joint portion of the lead electrode to which the insulating member is joined.

13. The semiconductor device according to claim 1 , comprising a plurality of the semiconductor elements.

14. The semiconductor device according to claim 13 , wherein the semiconductor elements are arranged in parallel.

15. The semiconductor device according to claim 1 , further comprising a plurality of the insulating members.

16. The semiconductor device according to claim 12 , wherein a roughened portion having a surface rougher than a region of said lead electrode other than said outer periphery of said through hole is formed on said lead electrode at an outer periphery of said through hole.

17. The circuit pattern is provided in a plurality of parts, The semiconductor device according to claim 1 , wherein the semiconductor element and the insulating member are bonded to upper surfaces of the circuit patterns that are different from each other.

18. 18. The semiconductor device according to claim 1, wherein the width of the lead electrode is not constant.

19. The semiconductor device according to claim 1 , wherein the semiconductor element is a reverse conducting IGBT.

20. The semiconductor device according to claim 1 , wherein a semiconductor material of the semiconductor element is SiC.

21. A main conversion circuit having the semiconductor device according to any one of claims 1 to 20, which converts input power and outputs the converted power; a control circuit that outputs a control signal for controlling the main conversion circuit to the main conversion circuit; A power conversion device comprising:

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