Electrical device and production method for electrical device

Abstract

This electrical device (1000) comprises: a heat sink (1); a vibration absorption member (2) that is disposed on the heat sink (1) and absorbs vibrations transmitted from the outside; and a semiconductor device (100) that is disposed on the vibration absorption member (2), is provided with a thermally conductive insulation member (16) on the bottom surface, and is disposed on the heat sink (1) with the vibration absorption member (2) therebetween. The vibration absorption member (2) functions so as to damp the vibration energy of vibrations transmitted from the heat sink (1) to the semiconductor device (100) due to vibrations from the outside.

Description

Electric power equipment and method for manufacturing the same

[0001] The present disclosure relates to an electric power device and a method for manufacturing an electric power device.

[0002] Electric power equipment incorporating semiconductor devices is used to control the power of a wide range of equipment, from industrial equipment to home appliances, automobiles, and trains. An example of an electric power equipment incorporating a semiconductor device is an inverter that converts direct current to alternating current. Since electric power equipment may be used in harsh environments, such as high or low temperatures, low pressures, or vibrations, it is required to maintain stable reliability even in such harsh environments. In particular, electric power equipment that operates at high voltages must ensure insulation reliability and efficiently dissipate heat generated by the operation of the semiconductor devices incorporated in the electric power equipment to the outside of the electric power equipment.

[0003] For example, in the semiconductor module unit described in Patent Document 1, a thermally conductive insulating sheet of a semiconductor device (power element) is bonded to a heat sink (heat spreader) via a thermally conductive layer (reactive grease, solvent-diluted grease), and the semiconductor device is further pressed against the heat sink by a disc spring. In the semiconductor module unit of Patent Document 1, insulation reliability is ensured by the thermally conductive insulating sheet, and bonding stability between the semiconductor device and the heat sink is ensured by the disc spring and the thermally conductive layer.

[0004] Patent No. 5383599

[0005] However, in the semiconductor module unit described in Patent Document 1, vibration energy is transmitted from the heat sink to the semiconductor device without attenuation, which may result in a problem in which components within the semiconductor device are damaged by external vibrations, resulting in a decrease in insulation reliability. In particular, since the thermally conductive insulating sheet of the semiconductor device plays a role in both heat exchange with the heat sink and ensuring insulation reliability, if the thermally conductive insulating sheet is damaged, i.e., if the thermally conductive insulating sheet breaks, chips, cracks, peels, or the like, there is a problem in that the insulation reliability of the semiconductor device is significantly reduced.

[0006] The present disclosure has been made to solve the above-mentioned problems, and aims to obtain electric power equipment with excellent long-term insulation reliability by attenuating the vibration energy applied to the mounted semiconductor device.

[0007] An electric power device according to the present disclosure includes: a heat sink; a vibration absorbing member disposed on the heat sink and configured to absorb vibrations; and a semiconductor device disposed on the vibration absorbing member.

[0008] A method for manufacturing an electric power device according to the present disclosure includes the steps of: forming a vibration absorbing member on a heat sink; and forming the vibration absorbing member on a bottom surface of a semiconductor device that faces the heat sink.

[0009] According to the electric power equipment of the present disclosure, by arranging a vibration absorbing member between the thermally conductive insulating member of the semiconductor device and the heat sink, it is possible to attenuate the vibration energy applied to the semiconductor device, particularly the thermally conductive insulating member provided on the bottom side of the semiconductor device, thereby preventing damage to the components of the electric power equipment and maintaining long-term insulation reliability.

[0010] 1 is a side view of the electric power equipment according to the first embodiment. FIG. 2 is a top view of the electric power equipment according to the first embodiment. FIG. 3 is a cross-sectional view of the electric power equipment according to the first embodiment taken along line A-A shown in FIG. 2 . FIG. 4 is a calculation example of the maximum electric field strength when the thickness of the vibration absorbing member of the electric power equipment according to the first embodiment is equal to the thickness of the thermally conductive insulating member of the semiconductor device. FIG. 5 is a calculation example of the maximum electric field strength when the thickness of the vibration absorbing member of the electric power equipment according to the first embodiment is twice the thickness of the thermally conductive insulating member of the semiconductor device. FIG. 6 is a flowchart for explaining a method of manufacturing the electric power equipment according to the first embodiment. FIG. 7 is a flowchart for explaining a modification of the method of manufacturing the electric power equipment according to the first embodiment. FIG. 8 is a top view of the electric power equipment according to the first modification of the first embodiment. FIG. 9 is a side view of the electric power equipment according to the second modification of the first embodiment. FIG. 10 is a side view of the electric power equipment according to the second embodiment. FIG. 11 is a side view of the electric power equipment according to the first modification of the second embodiment. FIG. 12 is a side view of the electric power equipment according to the second modification of the second embodiment. FIG. 13 is a side view of the electric power equipment according to the third embodiment. FIG. 14 is a side view of the electric power equipment according to the first modification of the third embodiment. FIG. 15 is a side view of the electric power equipment according to the fourth embodiment. FIG. 16 is a top view of the electric power equipment according to the fourth embodiment.

[0011] First Embodiment Fig. 1 is a side view of an electric power device 1000 according to a first embodiment, Fig. 2 is a top view of the electric power device 1000 according to the first embodiment, and Fig. 3 is a cross-sectional view of the electric power device 1000 according to the first embodiment taken along line A-A shown in Fig. 2.

[0012] The electric power device 1000 according to the first embodiment includes a heat sink 1, a vibration absorbing member 2, and a semiconductor device 100. The semiconductor device 100 includes a semiconductor chip 11, a lead frame 12, a heat spreader 13, a sealing portion 14, a wire 15, and a thermally conductive insulating member 16.

[0013] 1 , in the electric power equipment 1000, a vibration absorbing member 2 is disposed on a heat sink 1, and a semiconductor device 100 is disposed on the vibration absorbing member 2. In other words, the electric power equipment 1000 is configured such that the vibration absorbing member 2 is disposed between the semiconductor device 100 and the heat sink 1. The semiconductor device 100 is joined to the heat sink 1 via the vibration absorbing member 2.

[0014] As shown in FIG. 3, the semiconductor device 100 has a heat spreader 13 arranged on a thermally conductive insulating member 16, a semiconductor chip 11 arranged on the heat spreader 13, one end of a wire 15 connected to the semiconductor chip 11 and the other end connected to one end of a lead frame 12, and the above components are sealed by a sealing portion 14, with the other end of the lead frame 12 protruding from the sealing portion 14.

[0015] The heat sink 1 is a component responsible for dissipating heat from the electric power equipment 1000. Metals with high thermal conductivity, such as copper and aluminum, are suitable as materials for forming the heat sink 1. Furthermore, alloys of these metals with high thermal conductivity can also function as the heat sink 1. By connecting the heat sink 1 to a structure with a large surface area, such as a heat dissipation fin (not shown), the heat generated by the electric power equipment 1000 can be dissipated more efficiently. Furthermore, by integrating the heat sink 1 with the heat dissipation fin, the heat dissipation from the electric power equipment 1000 can be performed even more efficiently.

[0016] The vibration absorbing member 2 attenuates vibration energy transmitted to the semiconductor device 100 via the heat sink 1, and also serves as a member for dissipating heat generated in the semiconductor device 100, which is a heat source, as it operates, to the heat sink 1. Examples of materials that can be used to form the vibration absorbing member 2 include viscoelastic bodies such as silicone gel, urethane gel, and polyacrylamide gel. The vibration absorbing member 2 may also be formed using a mixture of these materials with the addition of a material with excellent thermal conductivity, such as silica, alumina, aluminum nitride, silicon nitride, carbon, or copper.

[0017] The viscoelastic material used as the constituent material of the vibration absorbing member 2 is a substance that has both the viscosity to absorb external vibrations and the elasticity to maintain its original shape. The vibration σ of a substance when a sinusoidal strain γ = γ0 sinωt is applied is expressed as σ = σ0 sinωt for an elastic body, and as σ = σ0 sin(ωt + π / 2) for a viscous body. On the other hand, a viscoelastic body exhibits behavior between that of an elastic body and a viscous body. In other words, a viscoelastic body is capable of attenuating the energy caused by vibration.

[0018] The energy loss G per cycle of vibration deformation of a viscoelastic body is expressed as G = (σ0 / γ0) × sinδ, and the loss factor is tanδ (0 < δ < π / 2). A larger loss factor is preferable. When using a viscoelastic body other than the viscoelastic bodies listed above, such as rubber, gel, or elastomer, as the constituent material of the vibration absorbing member 2, a material with a loss factor of 0.2 or greater is preferable. The thickness of the vibration absorbing member 2 can be designed taking into consideration both heat dissipation and insulation reliability. The vibration-damping properties of the vibration absorbing member 2 may be further improved by using a vibration-damping gel as the gel and a vibration-damping rubber as the rubber. Specific examples of vibration-damping rubber include acrylic rubber, silicone rubber, and fluororubber, which have excellent heat resistance. Furthermore, examples of butyl rubber, which has high damping properties, and butadiene rubber, which has low dynamic magnification, are also suitable. Specific examples of vibration-damping gel include silicone gel.

[0019] Fig. 4 shows an example of calculation of the maximum electric field strength when the thickness of the vibration absorbing member 2 is equal to the thickness of the thermally conductive insulating member 16, and Fig. 5 shows an example of calculation of the maximum electric field strength when the thickness of the vibration absorbing member 2 is twice the thickness of the thermally conductive insulating member 16, divided into cases with and without bubbles. Note that bubbles refer to bubbles generated inside the vibration absorbing member 2. The values ​​on the vertical axis in Figs. 4 and 5 are ratios to the maximum electric field strength when there is no vibration absorbing member 2, shown as Default. Note that ε s is the relative dielectric constant of the vibration absorbing member 2, ε m and represent the relative dielectric constant of the thermally conductive insulating member 16, respectively.

[0020] ε s ≦3ε m When the vibration absorbing member 2 is used, the ratio of the maximum electric field strength is 0.8 or less compared to when there is no vibration absorbing member 2, showing a significant electric field relaxation effect, and it can be seen that the maximum electric field strength is lower when the vibration absorbing member 2 is thicker. Furthermore, because the vibration absorbing member 2 is in direct contact with the semiconductor device 100, which is a heat source, it is necessary for the vibration absorbing member 2 to continue to maintain its function even when exposed to high temperatures for a long period equivalent to the product lifespan.

[0021] If the electric power equipment 1000 is used beyond the heat resistance of the vibration absorbing member 2, the vibration absorbing member 2 will suffer from problems such as a reduction in thickness due to solation or liquefaction, component elution, and a decrease in insulation reliability due to chemical reactions with other components, significantly impairing its function as a vibration absorber. For this reason, a material that has a tolerance of 10°C or more up to the point at which physical properties such as the vitrification temperature and solation temperature change is preferable as the material that constitutes the vibration absorbing member 2.

[0022] Furthermore, when the vibration absorbing member 2 is applied to a semiconductor device 100 that does not have a thermally conductive insulating member 16, the vibration absorbing member 2 must also function as the thermally conductive insulating member 16. Therefore, the material constituting the vibration absorbing member 2 must be a material having a volume resistivity of 10 or less within the operating temperature range of the electric power equipment 1000. 10 A viscoelastic body having physical properties of Ω·cm or more and a relative dielectric constant of 20 or less is used. The constituent material of the vibration absorbing member 2 is selected as described above, and the thickness of the vibration absorbing member 2 and other factors can be designed. As an example of the design, the thickness d of the vibration absorbing member 2 is s and the thickness d of the thermally conductive insulating member 16 m d s ≧d m The design should be such that the above relationship is satisfied.

[0023] 3, the semiconductor device 100 has at least one semiconductor chip 11, and the inside and outside of the semiconductor device 100 are electrically connected by a lead frame 12. There are various other components of the semiconductor device 100 other than those described above depending on the intended use, so these may be provided as appropriate.

[0024] The semiconductor chip 11 mounted on the semiconductor device 100 may be a semiconductor element for controlling large current, such as an IGBT (Insulated Gate Transistor), a MOS-FET (Metal-Oxide-Semiconductor Field-Effect Transistor), or a diode.

[0025] Si (silicon) is generally used as the semiconductor material for forming the semiconductor chip 11. Alternatively, the semiconductor chip 11 may be made of a wide bandgap semiconductor material such as SiC (silicon carbide), GaN (gallium nitride), or C (diamond), which are used as semiconductor materials for forming high-power semiconductor chips.

[0026] The semiconductor chip 11 made of a wide bandgap semiconductor has lower power loss and can operate at higher temperatures than the semiconductor chip 11 made of Si, which allows for miniaturization of the semiconductor device 100 itself and the power equipment 1000 incorporating the semiconductor device 100. While Fig. 3 illustrates an example in which one semiconductor chip 11 is incorporated in the power equipment 1000, as will be described later, it is also possible to incorporate multiple semiconductor chips 11 in one power equipment 1000.

[0027] The lead frame 12 is a component that provides electrical connection between the inside and outside of the semiconductor device 100. For this reason, metals with high electrical conductivity, such as gold, copper, or aluminum, or alloys of these metals, are suitable as materials for the lead frame 12. In the example of the semiconductor device 100 shown in FIG. 3, the lead frame 12 protrudes outward from the side of the semiconductor device 100 and has an L-shape. In addition to this example, the lead frame 12 can also function as the lead frame 12 even if it protrudes upward from the top surface of the semiconductor device 100. Furthermore, the lead frame 12 can also function as the lead frame 12 if it is linear or has other shapes.

[0028] The heat spreader 13 is a component for dissipating heat generated by the semiconductor chip 11 to the outside of the semiconductor device 100. Metals with high thermal conductivity, such as copper and aluminum, are suitable as materials for the heat spreader 13. The heat spreader 13 may also be made of an alloy of these metals. Although the heat spreader 13 and the lead frame 12 are shown as separate components in FIG. 3, they may also be an integrated structure.

[0029] The sealing portion 14 covers the entire semiconductor chip 11, heat spreader 13, and wires 15 and part of the lead frame 12, thereby providing insulation between the inside and outside of the semiconductor device 100. Because the insulation reliability of the sealing portion 14 can be reduced by factors such as peeling, air bubbles, and intrusion of foreign matter, it is desirable to manufacture the semiconductor device 100 by, for example, transfer molding using a mold.

[0030] The constituent material of the sealing portion 14 may be a resin with excellent insulating properties, such as epoxy, polyimide, polyamide, or polyamideimide, or a mixture of these resins with silica, alumina, aluminum nitride, or boron nitride added. The volume resistivity of these materials is such that the volume resistivity is 10 or less in the operating temperature range of the electric power equipment 1000. 10 Any material having a dielectric constant of Ω·cm or more and a relative dielectric constant of 20 or less may be used, such as gases such as SF6 and nitrogen, or other materials than those mentioned above.

[0031] The wires 15 electrically connect the semiconductor chip 11 and the lead frame 12. The material of the wires 15 is preferably a metal with high electrical conductivity, such as gold, copper, or aluminum, or an alloy of a metal with high electrical conductivity. However, the lead frame 12 may be directly bonded to the semiconductor chip 11 without using the wires 15.

[0032] The wire 15 may also be connected as a signal line for controlling the power of the semiconductor chip 11. When the wire 15 is used as a signal line, it serves to transmit a control signal from outside the semiconductor device 100 to the semiconductor chip 11 via a control terminal (not shown) and the wire 15. In addition, although the lead frame 12 is directly bonded to the heat spreader 13 in FIG. 3 , the electrical connection between the heat spreader 13 and the lead frame 12 may also be via the wire 15.

[0033] The thermally conductive insulating member 16 is thermally bonded to the heat spreader 13. The thermally conductive insulating member 16 is a component that provides insulation between the inside and outside of the semiconductor device 100 while dissipating heat generated in the semiconductor device 100. The thermally conductive insulating member 16 is made of an insulating resin sheet or a thin ceramic plate. When the thermally conductive insulating member 16 is a resin sheet, the material used is a resin with excellent insulating properties, such as epoxy, polyimide, polyamide, or polyamideimide, or a mixture of these resins with added silica, alumina, aluminum nitride, boron nitride, or the like.

[0034] When a ceramic thin plate is used as the thermally conductive insulating member 16, ceramics with excellent insulating and heat dissipating properties, such as silica, alumina, aluminum nitride, and silicon nitride, are used. To improve the insulating properties of the thermally conductive insulating member 16, a thicker thermally conductive insulating member 16 is preferable, while a thinner thermally conductive insulating member 16 is preferable to enhance heat dissipation. Therefore, the thickness of the thermally conductive insulating member 16 can be designed by taking into account the trade-off between these two. The thermally conductive insulating member 16 is preferably about 20 μm to 500 μm thick, with the upper limit of the thickness being about 2 mm. By using a material with excellent insulating properties for the thermally conductive insulating member 16, it is possible to reduce the thickness of the thermally conductive insulating member 16. For example, a material having a volume resistivity of 10 10 A material having a dielectric constant of Ω·cm or more and a relative dielectric constant of 20 or less is suitable.

[0035] <Method of Manufacturing Electric Power Device According to First Embodiment> FIG. 6 is a flowchart for explaining a method of manufacturing an electric power device according to the first embodiment.

[0036] In step S101, the semiconductor device 100 is manufactured. In step S102, the vibration absorbing member 2 is formed on the heat sink 1. In step S103, the semiconductor device 100 is placed on the vibration absorbing member 2. In step S104, post-processing such as case assembly and lead frame bonding is performed according to the shape of the electric power equipment 1000.

[0037] The vibration absorbing member 2 is degassed and hardened after being formed on the heat sink 1. Alternatively, the vibration absorbing member 2 may be formed into a sheet shape and then formed on the heat sink 1.

[0038] <Modification of the Manufacturing Method of Electric Power Device According to First Embodiment> FIG. 7 is a flowchart for explaining a modification of the manufacturing method of electric power device according to the first embodiment.

[0039] In step S201, the semiconductor device 100 is manufactured. In step S202, the uncured vibration absorbing material 2 is placed on the heat sink 1. In step S203, the uncured vibration absorbing material 2 is applied to the semiconductor device 100. In step S204, the semiconductor device 100 is placed on the uncured vibration absorbing material 2 on the heat sink 1. In step S205, the vibration absorbing material 2 is degassed and cured. In step S206, post-processing such as case assembly and lead frame bonding is performed according to the shape of the electric power equipment 1000.

[0040] Compared with the method for manufacturing electric power equipment according to the first embodiment, the modified method for manufacturing electric power equipment according to the first embodiment has an increased number of steps and is more complicated, but it can reduce the possibility of air bubbles getting into the vibration absorbing member 2. Although some effect can be obtained even if either step S202 or step S203 is omitted, it is preferable to perform both steps as shown in the flowchart of FIG.

[0041] Variation 1 of Embodiment 1. Fig. 8 is a top view of an electric power device 1100 according to Variation 1 of Embodiment 1. In the electric power device 1100, a plurality of semiconductor devices 100 are mounted on a single heat sink 1 via a vibration absorbing member 2. Depending on the function or voltage class required of the electric power device, the number of semiconductor devices 100 required to achieve the required function or voltage class are arranged on a single heat sink 1. In the example shown in Fig. 8, a total of 16 semiconductor devices 100 are mounted on a single electric power device 1100.

[0042] Modification 2 of Embodiment 1. FIG. 9 is a side view of an electric power device 1200 according to Modification 2 of Embodiment 1. The electric power device 1200 is configured to be applied to a double-sided cooling type semiconductor device 200. The electric power device 1200 is configured such that vibration absorbing members 2 are disposed on both the top and bottom surfaces of the semiconductor device 200, and the semiconductor device 200 is sandwiched between heat sinks 1 from both above and below. Even if the vibration absorbing member 2 is disposed only between one of the two heat sinks 1 and the semiconductor device 100, a certain degree of effect can be achieved. However, as shown in FIG. 9, it is preferable to dispose the vibration absorbing member 2 between each of the two heat sinks 1 and the semiconductor device 200 from the viewpoint of efficiently absorbing external vibrations.

[0043] <Effects of First Embodiment> As described above, according to the electric power equipment and the method for manufacturing an electric power equipment of the first embodiment, by disposing a vibration absorbing member between the thermally conductive insulating member of the semiconductor device and the heat sink, it is possible to attenuate the vibration energy applied to the semiconductor device, particularly the thermally conductive insulating member, thereby preventing damage to the members and providing an electric power equipment that can maintain long-term insulation reliability, and also providing the effect that such an electric power equipment can be easily manufactured.

[0044] Embodiment 2 Fig. 10 is a side view of an electric power device 1300 according to embodiment 2. The electric power device 1300 shown in Fig. 10 includes a case 3 as a pressing mechanism for pressing the semiconductor device 100 toward the heat sink 1. A pressing mechanism other than the case 3 may be used, such as pressing by a heavy object or pressing using a screw and spring mechanism, as long as it functions as a pressing mechanism.

[0045] Case 3 is a component for restricting movement of semiconductor device 100 due to vibration. In a configuration in which one power device mounts multiple semiconductor devices 100, such as power device 1100 according to Modification 1 of Embodiment 1, the pressing mechanism exemplified by case 3 serves to prevent contact between the semiconductor devices 100 and ensure insulation reliability. Examples of materials constituting case 3 include resins with excellent insulation properties, such as epoxy, polyimide, polyamide, or polyamideimide, or mixtures of resins with excellent insulation properties with added silica, alumina, aluminum nitride, boron nitride, or the like.

[0046] Although FIG. 10 shows an example in which the lead frame 12 of the semiconductor device 100 protrudes outside the case 3, the lead frame 12 does not have to penetrate the case 3. When the lead frame 12 protrudes outside the case 3, there is a high degree of design freedom, such as by arranging other components outside the case 3. On the other hand, when the lead frame 12 does not protrude through the case 3, the influence of vibration energy from the case 3 can be reduced, but other components must also be arranged inside the case 3, thereby reducing the design freedom of the semiconductor device 100. Furthermore, when the lead frame 12 protrudes outside the case 3, the influence of vibration energy from the case 3 can be reduced while ensuring design freedom by hollowing out a portion of the case 3 so that the lead frame 12 and the case 3 do not come into contact. However, if the force with which the case 3, which serves as a pressing mechanism, presses the vibration absorbing member 2 against the heat sink 1 is too strong, this is undesirable because it reduces the effect of the electric power equipment 1300 according to the second embodiment.

[0047] Variation 1 of Embodiment 2. Fig. 11 is a side view of electric power equipment 1400 according to Variation 1 of Embodiment 2. In electric power equipment 1400, buffer material 4 is disposed between semiconductor device 100 and case 3 to relieve stress. Electric power equipment 1400 has an effect of being able to relieve stress applied to semiconductor device 100 from case 3 by buffer material 4 while maintaining the function of limiting the range of movement of semiconductor device 100 by case 3.

[0048] As described above, the buffer material 4 is a component that relieves the stress of the case 3 pressing the semiconductor device 100 against the heat sink 1 while maintaining the function of limiting the range of movement of the semiconductor device 100 due to the case 3. Examples of materials that can be used to form the buffer material 4 include foams. Specific examples of foams include mixtures of resins such as urethane, polyethylene, natural rubber, and silicone rubber with the addition of a foaming agent such as N,N'-dinitrosopentamethylenetetramine. Because the buffer material 4 comes into contact with the semiconductor device 100, which generates high temperatures, it is more preferable to use a resin with excellent heat resistance, such as silicone rubber, as the base material for the above-mentioned materials. Furthermore, providing adhesiveness to the surface of the buffer material 4 is even more preferable, as it can reduce displacement of the buffer material 4 due to vibration.

[0049] Modification 2 of Embodiment 2. Fig. 12 is a side view of electric power equipment 1500 according to Modification 2 of Embodiment 2. In electric power equipment 1500, a vibration absorbing member 2 is disposed between semiconductor device 100 and case 3 to relieve stress. In electric power equipment 1500, stress applied to semiconductor device 100 from case 3 can be relieved by vibration absorbing member 2 while maintaining the function of limiting the range of movement of semiconductor device 100 by case 3.

[0050] <Effects of embodiment 2> As described above, according to the electric power equipment of embodiment 2, it is possible to restrict the movement of the semiconductor device by using a pressing mechanism that presses the semiconductor device against the vibration absorbing member, thereby preventing damage to the member and achieving the effect of maintaining the long-term insulation reliability of the electric power equipment.

[0051] 13 is a side view of an electric power device 1600 according to a third embodiment. The electric power device 1600 improves positioning accuracy during manufacturing by forming a recess 1a in the heat sink 1. That is, the semiconductor device 100 is placed by positioning the bottom surface of the semiconductor device 100 to correspond to the recess 1a on the heat sink side, thereby improving the positioning accuracy of the semiconductor device 100 relative to the heat sink 1.

[0052] Variation 1 of Embodiment 3 Fig. 14 is a side view of an electric power device 1700 according to Variation 1 of Embodiment 3. In the electric power device 1700, the vibration absorbing member 2 is disposed only in the recess 1b of the heat sink 1. By adopting such a configuration, the amount of material used to form the vibration absorbing member 2 can be reduced, which has the effect of reducing the manufacturing cost of the electric power device 1700.

[0053] <Effects of embodiment 3> As described above, according to the electric power equipment of embodiment 3, a recess is provided in the heat sink, and the semiconductor device is positioned so that the bottom surface of the semiconductor device corresponds to the recess on the heat sink side, thereby achieving the effect of easily obtaining an electric power equipment that can maintain long-term insulation reliability.

[0054] 15 and 16 are a side view and a top view of an electric power device 1800 according to a fourth embodiment. The electric power device 1800 reduces vibration energy applied to the lead frame 12 by arranging legs 5 so as to fill the gap between the lead frame 12 and the vibration absorbing member 2 of the semiconductor device 100. The legs 5 are arranged so that one end contacts the bottom surface of the lead frame 12 and the other end contacts the surface of the vibration absorbing member 2. The legs 5 may be provided on all of the lead frames 12 of the semiconductor device 100, or may be provided on only some of the lead frames 12.

[0055] The lead frame 12 of the semiconductor device 100 bends and temporarily deforms due to vibration. The amount of deformation is proportional to the length of the lead frame 12, and the bending may cause peeling inside the semiconductor device 100. Note that vibration energy refers to energy generated when the lead frame 12 vibrates due to external vibration. In the electric power equipment 1800 according to the fourth embodiment, by providing the legs 5 between the lead frame 12 and the vibration absorbing member 2, it becomes possible to absorb the vibration energy applied to the lead frame 12.

[0056] 9 is mounted on the power equipment 1200 according to the second modification of the first embodiment, the lead frame 12 of the semiconductor device 200 is long due to wiring, and therefore even a small amount of vibration energy can cause a large deflection, possibly resulting in peeling inside the semiconductor device 200. On the other hand, in the power equipment 1800 according to the fourth embodiment, the legs 5 are provided between the lead frame 12 and the vibration absorbing member 2, thereby making it possible to absorb the vibration energy applied to the lead frame 12.

[0057] The legs 5 are components that support the lead frame 12. As described above, they are disposed between the lead frame 12 and the vibration absorbing member 2. Examples of materials that can be used to form the legs 5 include resins with excellent insulating properties, such as epoxy, polyimide, polyamide, or polyamideimide, or mixtures of resins with excellent insulating properties to which silica, alumina, aluminum nitride, or boron nitride has been added. To reduce the weight of the power equipment, the legs 5 can also function as such if a mixture of resins such as urethane, polyethylene, natural rubber, or silicone rubber to which a foaming agent has been added is used, which is the same material as the foam that is an example of the sealing portion 14.

[0058] <Effects of embodiment 4> As described above, according to the electric power equipment of embodiment 4, since legs are provided between the lead frame and the vibration absorbing member, it is possible to absorb the vibration energy applied to the lead frame, thereby achieving the effect of obtaining an electric power equipment with superior long-term insulation reliability.

[0059] Although the present disclosure describes various exemplary embodiments and examples, the various features, aspects, and functions described in one or more embodiments are not limited to application to a particular embodiment, but may be applied to the embodiments alone or in various combinations.

[0060] Therefore, countless variations not illustrated are conceivable within the scope of the technology of the present disclosure, including, for example, cases where at least one component is modified, added, or omitted, and cases where at least one component is extracted and combined with a component of another embodiment.

[0061] REFERENCE SIGNS LIST 1 heat sink, 1a, 1b recess, 2 vibration absorbing member, 3 case, 4 cushioning material, 5 leg portion, 11 semiconductor chip, 12 lead frame, 13 heat spreader, 14 sealing portion, 15 wire, 16 thermally conductive insulating member, 100, 200 semiconductor device, 1000, 1100, 1200, 1300, 1400, 1500, 1600, 1700, 1800 electric power equipment

Claims

1. An electric power device comprising: a heat sink; a vibration absorbing member arranged on the heat sink and absorbing vibrations; and a semiconductor device arranged on the vibration absorbing member.

2. The electric power equipment according to claim 1, characterized in that the semiconductor device has a thermally conductive insulating material provided on the bottom side thereof, the thermally conductive insulating material being disposed on the heat sink via the vibration absorbing material.

3. The electric power device according to claim 1 or 2, characterized in that the vibration absorbing member is made of a viscoelastic material.

4. The electric power device according to claim 3, wherein the viscoelastic body is any one of a gel, a rubber, and an elastomer.

5. The electric power device according to claim 4, wherein the gel is any one of a silicone gel, a urethane gel, and a polyacrylamide gel.

6. The electric power device according to claim 1 or 2, characterized in that the vibration absorbing member is an anti-vibration gel or an anti-vibration rubber.

7. An electric power device as claimed in any one of claims 1 to 6, characterized in that the vibration loss coefficient of the vibration absorbing member is 0.2 or more.

8. The volume resistivity of the vibration absorbing member is 10 10 8. The electric power device according to claim 1, wherein the dielectric constant is Ω·cm or more and a relative dielectric constant is 20 or less.

9. The relative dielectric constant ε of the vibration absorbing material s and the relative dielectric constant ε of the thermally conductive insulating member m But, ε s ≦3ε m 3. The electric power device according to claim 2, wherein the relationship is as follows:

10. Thickness d of the vibration absorbing member s and the thickness d of the thermally conductive insulating member m But, d s ≧d m The electric power device according to claim 2 or 9, characterized in that the electric power device has the following relationship:

11. The electric power device according to any one of claims 1 to 10, further comprising a pressing mechanism for pressing the semiconductor device and the vibration absorbing member against the heat sink.

12. The electric power device according to claim 11, further comprising a buffer material provided between said semiconductor device and said pressing mechanism.

13. An electric power device according to any one of claims 1 to 12, characterized in that a recess having a bottom surface larger than the bottom surface of the semiconductor device is formed on one surface of the heat sink opposite the bottom surface of the semiconductor device.

14. The electric power device according to claim 13, wherein the vibration absorbing member is disposed only inside the recess.

15. The electric power equipment according to any one of claims 1 to 14, wherein the semiconductor device has a lead frame protruding from a side portion, and a leg portion is provided between the lead frame and the heat sink, the leg portion having one end in contact with the lead frame and the other end in contact with the heat sink.

16. A method for manufacturing an electric power device, comprising: a step of forming a vibration absorbing member on a heat sink; and a step of forming the vibration absorbing member on a bottom surface of a semiconductor device that faces the heat sink.

17. A method for manufacturing an electric power device, comprising the steps of: forming a vibration absorbing member on a heat sink; and arranging a semiconductor device on the vibration absorbing member.

18. A method for manufacturing electric power equipment as described in claim 16, further comprising the steps of: forming the vibration absorbing member on the heat sink, applying the uncured vibration absorbing member onto the heat sink; and forming the vibration absorbing member on the semiconductor device, applying the vibration absorbing member to the semiconductor device, placing the semiconductor device on the heat sink, and degassing and curing the vibration absorbing member.

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