JP2016163024A - Power module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power module in which the short-circuit capacity of a power semiconductor element is improved compared with a conventional semiconductor device (especially, a power module), while reducing the manufacturing cost.SOLUTION: A power module includes a power semiconductor element 1 having a first principal surface 1a and a second principal surface 1b located on the opposite side of the first principal surface 1a, an electrode 2 formed on the first principal surface 1a and having a third principal surface 2a, a third conductor 8 as a conductive member connected electrically with the power semiconductor element 1, a wire 10 as a wiring part connecting the power semiconductor element 1 and third conductor 8 electrically, and a heat capacity body 11 formed on the third principal surface 2a of the electrode 2. The wire 10 is partially bonded to the electrode 2 on the third principal surface 2a, and the heat capacity body 11 is formed on the surface region of the third principal surface 2a including the junction of the electrode 2 and wire 10.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a power module, and more particularly to a technique for improving a short-circuit resistance of a power module.

  A power semiconductor element is insulated and sealed together with a circuit board or the like to constitute a power module. In the power module, the power semiconductor element and the circuit board are generally electrically connected by ultrasonic bonding (wire bonding) of a metal wire. It is connected.

  On the other hand, a technique for connecting a power semiconductor element and a circuit board by a plate-like wiring material soldered to an electrode of the power semiconductor element instead of a metal wire is also known (for example, JP-A-2006-210519). Or JP 2001-332664 A).

  When a power semiconductor element (for example, a diode, an IGBT (Insulated Gate Bipolar Transistor), a MOSFET (Metal Oxide Semiconductor Field Effect Transistor), etc.) is short-circuited to a power source due to an accident, a large current flows through the element and heat is rapidly generated for several microseconds. Device destruction in a short period of 10 to 10 microseconds. The time from short circuit to element destruction is conventionally called short circuit tolerance.

  In order to prevent element destruction due to a power supply short circuit, it is necessary to design such that the short circuit withstand capability is longer than the time from when the protection circuit detects the short circuit until it operates.

  However, as a trend of the world, the diameter of the power semiconductor element (chip shrink) is reduced to reduce the cost, and the power semiconductor element is thinned to reduce the on-resistance. In either case, since the energy density generated when the power semiconductor element is short-circuited to the power source increases, the short-circuit tolerance is shortened. From the above viewpoint, there is a demand for technical development for improving the short-circuit tolerance of power semiconductor elements.

  In general, improvement of the short-circuit withstand capability of the power semiconductor element is achieved by creating a structure of the power semiconductor element itself, but an external structure of the power semiconductor element is also created.

  In Japanese Patent Laid-Open No. 2006-319213, in order to improve load short-circuit withstand capability, a metal electrode having a thickness of 50 μm or more is in contact with the surface on the front side of the semiconductor element portion, and the metal electrode and the plate-like wiring are provided on the surface. A contacted semiconductor device is described.

JP 2006-210519 A JP 2001-332664 A JP 2006-319213 A

However, in the conventional semiconductor device as described above, since the wiring is plate-shaped, it is necessary to design and manufacture a dedicated plate-shaped wiring for each type of semiconductor device having a different circuit arrangement, which increases the manufacturing cost. (On the other hand, when the wiring is used for general purposes, the degree of freedom in circuit design is low.)
Further, increasing the thickness of the electrode has high technical barriers and high manufacturing costs.

  The present invention has been made to solve the above-described problems. The main object of the present invention is to provide a power module in which the short-circuit withstand capability of the power semiconductor element is improved and the manufacturing cost is reduced as compared with the above-described conventional semiconductor device (particularly, the power module).

  A power module according to the present invention is formed on a power semiconductor element having a first main surface and a second main surface located on the opposite side of the first main surface, and on the first main surface. An electrode having a third main surface, a conductive member electrically connected to the power semiconductor element, a wiring portion electrically connecting the power semiconductor element and the conductive member, And a heat capacity body formed on the third main surface of the electrode. A part of the wiring portion is bonded to the electrode on the third main surface, and the heat capacity body is on a surface region of the third main surface including a bonding portion between the electrode and the wiring portion. Is formed.

  According to the present invention, since the heat capacity body covers the joint between the electrode and the wiring section and the surface of the electrode adjacent to the joint, the rapid element heat generated when the power semiconductor element is short-circuited is dissipated to the heat capacity body. Thus, the time from the short circuit to the breakdown of the power semiconductor element, that is, the short circuit tolerance can be increased. In addition, since it is not necessary to dissipate the element heat generated by the wiring portion, the wiring portion does not need to be plate-shaped, and can be a metal wire, for example. As a result, it is possible to provide a power module that has improved short-circuit tolerance and reduced manufacturing costs.

3 is a cross-sectional view for explaining the power module according to Embodiment 1. FIG. It is the fragmentary sectional view seen from the line segment II-II in FIG. 3 is a partial perspective view for explaining the power module according to Embodiment 1. FIG. 3 is a flowchart of a method for manufacturing the power module according to the first embodiment. FIG. 6 is a cross-sectional view for explaining a power module according to a second embodiment. It is the fragmentary sectional view seen from line segment VI-VI in FIG. FIG. 6 is a partial perspective view for explaining a power module according to a third embodiment. FIG. 6 is a partial perspective view for explaining a power module according to a fourth embodiment. FIG. 10 is a partial perspective view for explaining a power module according to a fifth embodiment.

  Embodiments according to the present invention will be described below with reference to the drawings. In the following drawings, the same or corresponding parts are denoted by the same reference numerals, and description thereof will not be repeated.

(Embodiment 1)
A power module 100 according to Embodiment 1 will be described with reference to FIGS. FIG. 1 is a cross-sectional view of a power module 100 according to the first embodiment. FIG. 2 is a partial cross-sectional view taken along line II-II in FIG. FIG. 3 is a partial perspective view for explaining the power module 100 according to the first embodiment, and shows only the power semiconductor element 1, the electrode 2, the wire 10, and the heat capacity body 11 in the power module 100. As shown in FIG. 1, the power module 100 includes a power semiconductor element 1, an electrode 2, a third conductor 8 as a conductive member, a wire 10 as a wiring part, and a heat capacity body 11.

  The power semiconductor element 1 is, for example, an IGBT (Insulated Gate Bipolar Transistor) or a MOSFET (Metal Oxide Semiconductor Field Effect Transistor). The power semiconductor element 1 has a first main surface 1a and a second main surface 1b located on the opposite side of the first main surface 1a. An electrode 2 is formed on the first main surface 1a.

  Although the material which comprises the electrode 2 should just be arbitrary electroconductive materials, it is aluminum (Al), for example. The film thickness of the electrode 2 can be less than 50 μm, and may be, for example, 1 μm or more and 10 μm or less. The electrode 2 has a surface joined to the first main surface 1a of the power semiconductor element 1 and a third main surface 2a located on the opposite side of the surface. The planar shape of the electrode 2 when the third main surface 2a is viewed in plan can be an arbitrary shape, for example, a square shape.

  The second main surface 1 b of the power semiconductor element 1 is bonded to the circuit board 3 via the bonding member 4. The circuit board 3 is configured by laminating a first conductor 5, an insulating substrate 6, and a second conductor 7 or a third conductor 8. The first conductor 5 and the second conductor 7 are configured to sandwich the insulating substrate 6, and are electrically insulated by the insulating substrate 6. The first conductor 5 and the third conductor 8 are configured to sandwich the insulating substrate 6, and are electrically insulated by the insulating substrate 6. The second conductor 7 and the third conductor 8 are arranged on the insulating substrate 6 with a space therebetween. The second main surface 1 b of the power semiconductor element 1 is joined to the second conductor 7 via the joining member 4.

  The bonding member 4 is, for example, a low-temperature sintered material using silver nanoparticles, a liquid phase diffusion bonding material using a copper (Cu) -tin (Sn) alloy, or solder.

Although the material which comprises the 1st conductor 5, the 2nd conductor 7, and the 3rd conductor 8 can be made into the arbitrary materials which have high heat conductivity, for example, at least any one of copper (Cu) and aluminum (Al) It is a material containing one. The material constituting the insulating substrate 6 may be any material having electrical insulation and high thermal conductivity. For example, silicon nitride (SiN), aluminum nitride (AlN), and alumina (Al ₂ O ₃ ) or a resin material such as an epoxy resin.

  The electrode 2 and the third conductor 8 are electrically connected via a plurality of wires 10 (wiring portions). The plurality of wires 10 are partially bonded to the electrode 2 on the third main surface 2a (first bonding portion 10A), and the other portion (second bonding portion 10B) is bonded to the third conductor 8. Yes. In other words, each of the plurality of wires 10 includes a first joint portion 10 </ b> A including a joint portion with the electrode 2 and a second joint portion 10 </ b> B including a joint portion with the third conductor 8. The first joint portion 10 </ b> A is formed on one end side of the wire 10, and the second joint portion 10 </ b> B is formed on the other end side of the wire 10. Each first joint portion 10A of the plurality of wires 10 is formed, for example, on the third main surface 2a so as to extend in parallel with a space therebetween. The material constituting the wire 10 can be any material that is conductive and can be formed as a bonding wire, such as Cu or Al. The cross-sectional shape perpendicular to the extending direction of the wire 10 may be an arbitrary shape, for example, a circular shape. The wire diameter of the wire 10 is, for example, not less than 100 μm and not more than 500 μm.

  The second conductor 7 is joined to the external terminal 9 </ b> A in a region other than the region joined to the power semiconductor element 1. Thereby, the power semiconductor element 1 and the external terminal 9 </ b> A are electrically connected via the second conductor 7. The third conductor 8 is joined to the external terminal 9 </ b> B in a region other than the region joined to the wire 10. Thereby, the power semiconductor element 1 and the external terminal 9 </ b> B are electrically connected via the third conductor 8.

  A heat capacity body 11 is formed on the entire surface of the third main surface 2 a of the electrode 2. In other words, the heat capacity body 11 is formed on the surface region of the third main surface 2 a including the joint portion between the electrode 2 and the wire 10. The surface region covered with the heat capacity body 11 on the third main surface 2a extends over the entire surface of the third main surface 2a. That is, the heat capacity body 11 is formed on the entire surface of the third main surface 2a. The electrode 2 and the heat capacity body 11 are formed so as to overlap when the third main surface 2a is viewed in plan. When the planar shape of the electrode 2 when the third main surface 2a is viewed in plan is a square shape, the planar shape of the heat capacity body 11 when viewed in plan is the square shape. When the planar shape of the electrode 2 when the third main surface 2a is viewed in plan is a circular shape, the planar shape of the heat capacity body 11 when viewed in plan is a circular shape.

  The material constituting the heat capacity body 11 is preferably a material that is liquid at the time of mounting (for example, at the time of application or dripping) and can be solidified by heat treatment after the completion of mounting. Moreover, although the material which comprises the heat capacity body 11 is a material whose heat conductivity is higher than the material which comprises the sealing body 12 mentioned later at least, it is preferable that it is a material which has higher heat conductivity. Materials constituting the heat capacity body 11 are, for example, solder, silver (Ag) paste (in which Ag particles are dispersed in a resin, and the resin is cured by heat treatment), sintered Ag paste (in which Ag particles are dispersed in a solvent). Such as those in which the solvent is volatilized by the heat treatment and the Ag particles are sintered), high heat conductive resins (fillers made of a material having high heat conductivity are dispersed in the resin), and the like. The thermal conductivity of the heat capacity body 11 is preferably, for example, 5 W / (m · K) or more, and more preferably 50 W / (m · K) or more.

  Each first joint portion 10 </ b> A of the plurality of wires 10 is embedded in the heat capacity body 11. In other words, in the surface of the first joint portion 10 </ b> A of the wire 10, a region other than the region in contact with the third main surface 2 a is in contact with the heat capacity body 11. On the third main surface 2 a of the electrode 2, a region other than the region in contact with the first joint portion 10 </ b> A of the wire 10 is in contact with the heat capacity body 11. The heat capacity body 11 uniformly covers, for example, the first joint portions 10 </ b> A of the plurality of wires 10 and the third main surface 2 a of the electrode 2. At this time, the film thickness of the heat capacity body 11 is thicker than the thickness in the direction perpendicular to the third main surface 3 a of the first joint portion 10 </ b> A of the wire 10, for example, thicker than the wire diameter of the wire 10.

  The film thickness of the heat capacity body 11 is sufficient if it is 100 μm or less from the viewpoint of improving the short-circuit resistance, and can be determined according to the thermal conductivity of the material constituting the heat capacity body 11. This is due to the following reason.

  The time from the short-circuiting of the power semiconductor element 1 to the element destruction is as short as several μs to 10 μs, and the distance that heat generated in the power semiconductor element 1 is transmitted through the heat capacity body 11 within this time is the heat of the heat capacity body 11. Depends on conductivity. Therefore, the effect of improving the short-circuit withstand capability by the heat capacity body 11 becomes maximum when the film thickness of the heat capacity body 11 is made equal to the distance, and reaches the peak even if the film thickness of the heat capacity body 11 is made larger than the distance.

  The present inventors conducted a transient heat transfer analysis using an analytical model in which the heat capacity body 11 is formed on the entire third main surface 2a of the electrode 2, and when the film thickness of the heat capacity body 11 is about 1 mm. It was confirmed that the temperature of the upper surface of the heat capacity body 11 remained almost at the initial temperature even after 10 μs from the start of heat generation, regardless of the material constituting the heat capacity body 11. For example, even when the material constituting the heat capacity body 11 is copper (Cu) having a thermal conductivity of 400 W / (m · K), the upper surface of the heat capacity body 11 after 10 μs from the start of heat generation remains substantially at the initial temperature. Met. From the result of the transient heat transfer analysis by the present inventors, for example, when the material constituting the heat capacity body 11 is an epoxy resin (thermal conductivity 5 W / (m · K)) containing an inorganic filler, the film thickness of the heat capacity body 11 is When the thickness was about 10 μm, the effect of improving the short-circuit resistance was maximized. When the material constituting the heat capacity body 11 is solder (thermal conductivity 70 W / (m · K)), the thickness of the heat capacity body 11 is about 50 μm and the sintered Ag paste (heat conductivity 200 W / (m · K). )), The effect of improving the short-circuit resistance is maximized when the film thickness of the heat capacity body 11 is about 80 μm, and it has been confirmed that the effect reaches a peak even when the film thickness is increased.

  In addition, when the film thickness of the heat capacity body 11 has a distribution in a plane parallel to the third main surface 2a, the effect of improving the short-circuit resistance by the heat capacity body 11 is the minimum value of the film thickness of the heat capacity body 11. Therefore, the minimum value is preferably determined according to the thermal conductivity of the constituent material of the heat capacity body 11.

  The sealing body 12 includes the power semiconductor element 1 and the circuit board 3 excluding a surface (lower surface) located on the opposite side of the surface bonded to the insulating substrate 6 in the first conductor 5 and a part of the external terminals 9A and 9B. The external terminal 9, the wire 10, and the heat capacity body 11 are provided.

  Next, with reference to FIG. 4, the manufacturing method of the power module 100 which concerns on Embodiment 1 is demonstrated.

  First, the power semiconductor element 1 mounted on the circuit board 3 is prepared (S10). In the power semiconductor element 1, the electrode 2 is formed on the first main surface 1 a, and the second main surface 1 b is bonded to the second conductor 7 of the circuit board 3 via the bonding member 4. In the circuit board 3, the first conductor 5 and the insulating substrate 6 are joined, and the insulating substrate 6 and the second conductor 7 or the third conductor 8 are joined.

  Next, the wire 10 for electrically connecting the electrode 2 and the third conductor 8 is formed (S20). The wire 10 is bonded to the electrode 2 and the third conductor 8 by an ultrasonic bonding method or the like. Thereby, the wire 10 having the first joint portion 10A is formed.

  Next, the heat capacity body 11 is formed on the third main surface 2a of the electrode 2 (S30). The method for forming the heat capacity body 11 may be arbitrarily determined according to the material constituting the heat capacity body 11.

  When the material constituting the heat capacity body 11 is solder, the solder can be wetted and spread on the electrode 2 and the wire 10 by, for example, soldering using an ultrasonic soldering iron, and the heat capacity body 11 can be cooled. Can be formed.

  When the material constituting the heat capacity body 11 is an Ag paste, for example, the Ag paste material is dropped on the third main surface 2a of the electrode 2 and then held at a high temperature to cure the resin (curing). Thus, the heat capacity body 11 can be formed.

  When the material constituting the heat capacity body 11 is a sintered Ag paste, for example, the sintered Ag paste is dropped on the third main surface 2a of the electrode 2 and then held at a high temperature to be sintered Ag paste. The heat capacity body 11 can be formed by volatilizing the solvent therein and sintering the Ag particles.

  In any case, after supplying the liquid material to be the heat capacity body 11 on the surface region of the third main surface 2a including the joint portion between the electrode 2 and the wire 10, the heat capacity body 11 is solidified by supplying it. Form. When the heat capacity body 11 is formed, the wire 10 receives contact with the liquid material to be the heat capacity body 11, but the contact partner is made of a liquid material, so that the wire 10 is prevented from being physically damaged by the contact. be able to. The heat capacity body 11 can be easily formed on the entire surface of the third main surface 2a by controlling the amount of application or dropping of the liquid material to be the heat capacity body 11 and the application or dropping method.

  Next, the sealing body 12 is formed (S40). Specifically, the sealing target material (including the power semiconductor element 1, the electrode 2, the circuit board 3, a part of the external terminal 9, the wire 10, and the heat capacity body 11) on which the heat capacity body 11 is formed is sealed. 12 to seal. The sealing body 12 is formed by, for example, a transfer mold method. In this way, the power module 100 according to Embodiment 1 can be obtained.

  Next, functions and effects of the power module 100 according to Embodiment 1 will be described. The power module 100 according to Embodiment 1 includes a power semiconductor element 1 having a first main surface 1a and a second main surface 1b located on the opposite side of the first main surface 1a, and a first main surface An electrode 2 having a third main surface 2a, a third conductor 8 as a conductive member electrically connected to the power semiconductor element 1, and the power semiconductor element 1 and the third conductor. 8 and a heat capacity body 11 formed on the third main surface 2 a of the electrode 2. A part of the wire 10 is bonded to the electrode 2 on the third main surface 2 a, and the heat capacity body 11 is formed on the surface region of the third main surface 2 a including the bonding portion between the electrode 2 and the wire 10. Has been.

  In this way, heat generated when the power semiconductor element 1 is short-circuited can be radiated to the heat capacity body 11 via the electrode 2. At this time, the electrode 2 need not be thick and have a large heat capacity. That is, in the power module 100, the short circuit withstand capability of the power semiconductor element 1 is improved and the manufacturing cost is reduced as compared with the conventional semiconductor device (particularly, the power module).

  In the power module 100 according to the first embodiment, the first joint portion 10 </ b> A of the wire 10 is embedded in the heat capacity body 11. In this way, all the regions other than the joint with the electrode 2 in the first joint portion 10A are in contact with the heat capacity body 11, so that the heat of the first joint portion 10A is effective on the heat capacity body 11. Heat can be released.

  In the power module, Joule heat is generated at the junction between the wire and the electrode due to current concentration during continuous energization, and a hot spot is formed. This causes the reliability of the joint portion to be impaired. On the other hand, the power module 100 relaxes the hot spot by effectively spreading the heat generated in the first joint portion 10A by the heat capacity body 11 in the in-plane direction, and the joint portion between the electrode 2 and the wire 10. Reliability can be improved.

  In the power module 100 according to the first embodiment, the heat capacity body 11 is formed on the entire third main surface 2 a including the joint portion between the electrode 2 and the wire 10. That is, the heat capacity body 11 covers the entire surface of the third main surface 2a. In this way, the heat radiation effect from the power semiconductor element 1 to the heat capacity body 11 via the third main surface 2a of the electrode 2 can be maximized, and the short-circuit tolerance of the power semiconductor element 1 can be more effectively improved. Can be improved.

  In the power module 100 according to the first embodiment, the wire 10 is a bonding wire. In this way, the wire 10 is easily formed even for a plurality of types of power modules 100 in which the circuit arrangement is different in the power module 100 and the relative positional relationship between the electrode 2 and the third conductor 8 is different. obtain. Therefore, the power module 100 including such a wire 10 does not need to prepare a dedicated wiring portion corresponding to the circuit arrangement in order to improve the short-circuit tolerance of the power semiconductor element 1, and is identical to the general-purpose wire 10. The short-circuit resistance is improved by the heat capacity body 11 made of a material. That is, the power module 100 has improved short-circuit tolerance, high degree of freedom in circuit design, and low manufacturing cost.

  In the method for manufacturing the power module 100 according to the first embodiment, the heat capacity body 11 is supplied as a liquid material onto the third main surface 2a of the electrode 2 to which the wire 10 is bonded, and then the liquid material is solidified. Is formed. Therefore, even if a general-purpose bonding wire is used as the wire 10, the wire 10 is prevented from being physically damaged when the heat capacity body 11 is formed. As a result, the power module 100 in which the short-circuit withstand capability of the power semiconductor element 1 is improved can be manufactured at low cost without impairing the reliability of the joint between the electrode 2 and the wire 10.

(Embodiment 2)
Next, the power module 100 according to Embodiment 2 will be described with reference to FIGS. FIG. 5 is a cross-sectional view of power module 100 according to the second embodiment. 6 is a partial cross-sectional view taken along line VI-VI in FIG. The power module 100 according to the second embodiment has basically the same configuration as that of the power module 100 according to the first embodiment, but a part of the surface of a part of the wire 10 (first joint portion 10A) is a heat capacity body. 11 is different in that it is exposed.

  On the surface of the first joint portion 10A of the wire 10, a part of the region other than the region in contact with the third main surface 2a is exposed from the heat capacity body 11, and the other is in contact with the heat capacity body 11. ing. In other words, the film thickness of the heat capacity body 11 (the minimum value when there is a film thickness distribution on the third main surface 2a) is in a direction perpendicular to the third main surface 3a of the first joint portion 10A of the wire 10. It is thinner than the thickness, for example, thinner than the wire diameter of the wire 10.

  Even in this case, on the third main surface 2 a of the electrode 2, the region other than the region in contact with the first joint portion 10 </ b> A of the wire 10 is in contact with the heat capacity body 11. Thus, the heat generated when the power semiconductor element 1 is short-circuited can be radiated to the heat capacity body 11. As a result, the power module 100 according to the second embodiment can achieve the same effects as the power module 100 according to the first embodiment.

(Embodiment 3)
Next, a power module 100 according to Embodiment 3 will be described with reference to FIG. FIG. 7 is a partial perspective view for explaining the power module 100 according to the third embodiment, and shows only the power semiconductor element 1, the electrode 2, the wire 10, and the heat capacity body 11 in the power module 100. The power module 100 according to the third embodiment has basically the same configuration as that of the power module 100 according to the first embodiment. However, the heat capacity body 11 includes a joint portion between the electrode 2 and the wire 10. It differs in that it is formed on a part of the surface 2a. In other words, the third main surface 2 a is different in that a part of the region where the joint portion between the electrode 2 and the wire 10 is not formed is exposed from the heat capacity body 11.

  The heat capacity body 11 partially covers the third main surface 2 a of the electrode 2. The portion exposed from the heat capacity body 11 on the third main surface 2 a is formed in the outer peripheral portion in the planar shape of the electrode 2. That is, the portion exposed from the heat capacity body 11 on the third main surface 2 a is located on the third main surface 2 a in the portion farthest from the bonding portion between the electrode 2 and the wire 10.

  The heat capacity body 11 is formed so as to overlap a part of the electrode 2 when the third main surface 2 a is viewed in plan. The planar shape of the heat capacity body 11 when the third main surface 2a is viewed in plan is, for example, a circular shape. The planar shape of the electrode 2 when viewed in plan is, for example, a square shape.

  Even in this case, since the power module 100 according to the third embodiment has basically the same configuration as the power module 100 according to the first embodiment, the same effect as the power module 100 according to the first embodiment. Can be played.

  The heat capacity body 11 in the third embodiment can be formed by an arbitrary method in the same manner as the heat capacity body 11 in the first embodiment. For example, a liquid material to be the heat capacity body 11 is dropped from the center position of the electrode 2 by a syringe or the like. By doing so, it can be easily formed by supplying onto the third main surface 2a and then solidifying the liquid material. That is, the power module 100 according to the third embodiment can be easily manufactured equivalently or more easily than the power module 100 according to the first embodiment.

  As described above, the power module 100 according to the third embodiment can be easily manufactured while the short-circuit tolerance of the power semiconductor element 1 is improved. In the power module 100 according to the third embodiment, the area of the surface region of the third main surface 2a that is covered with the heat capacity body 11 is the surface region of the power module 100 according to the first embodiment. Therefore, the magnitude of the effect of improving the short-circuit resistance by the heat capacity body 11 is not as large as that of the power module 100 according to the first embodiment.

  In the power module 100 according to the third embodiment, a part of the surface of a part of the wire 10 (first joint portion 10A) may be exposed from the heat capacity body 11. In this way, since the power module 100 according to the second embodiment has basically the same configuration, the same effects as the power module 100 according to the second embodiment can be obtained.

(Embodiment 4)
Next, the power module 100 according to Embodiment 4 will be described with reference to FIG. FIG. 8 is a partial perspective view for explaining the power module 100 according to the fourth embodiment, and shows only the power semiconductor element 1, the electrode 2, the wire 10, and the heat capacity body 11 in the power module 100. The power module 100 according to the fourth embodiment has basically the same configuration as the power module 100 according to the first embodiment, but differs in that the wiring portion is a ribbon wire 13.

  Even in this case, the heat capacity body 11 is formed on the surface region of the third main surface 2a including the joint portion between the electrode 2 and the ribbon wire 13, and the electrode 2 and the heat capacity body 11 are formed on the third main surface 2a. A part of the ribbon wire 13 that is joined (first joining portion 13 </ b> A) is embedded in the heat capacity body 11. Therefore, the power module 100 according to the fourth embodiment can achieve the same effects as the power module 100 according to the first embodiment.

  A part of the surface of the first joint portion 13 </ b> A of the ribbon wire 13 may be exposed from the heat capacity body 11. If it does in this way, there can exist an effect similar to power module 100 concerning Embodiment 2.

(Embodiment 5)
Next, with reference to FIG. 9, the power module 100 which concerns on Embodiment 5 is demonstrated. FIG. 9 is a partial perspective view for explaining the power module 100 according to the fifth embodiment, and shows only the power semiconductor element 1, the electrode 2, the wire 10, and the heat capacity body 11 in the power module 100. The power module 100 according to the fifth embodiment has basically the same configuration as the power module 100 according to the first embodiment, but the wiring portion is made of a conductive material and includes a portion that protrudes from the heat capacity body 11. It differs in that it is a member 14.

  The heat capacity body 11 is formed on the surface region of the third main surface 2a including the joint portion between the electrode 2 and the protruding member 14, and the protruding member is bonded to the electrode 2 on the third main surface 2a. A part of 14 (first joining portion 14 </ b> A) is embedded in the heat capacity body 11. Therefore, the power module 100 according to the fifth embodiment can achieve the same effects as the power module 100 according to the first embodiment.

  Although the embodiments of the present invention have been described above, it is also planned from the beginning to combine the configurations of the above-described embodiments as appropriate.

  It should be thought that embodiment disclosed this time is an illustration and restrictive at no points. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  The present invention is particularly advantageously applied to a power module including a power semiconductor element that rapidly generates heat when a large current flows during a short circuit.

  DESCRIPTION OF SYMBOLS 1 Power semiconductor element, 1a 1st main surface, 1b 2nd main surface, 2 electrode, 2a 3rd main surface, 3 Circuit board, 4 joining member, 5 1st conductor, 6 Insulating substrate, 7 2nd conductor , 8 Third conductor, 9, 9A, 9B External terminal, 10 wire, 10A, 13A, 14A First joint portion, 10B Second joint portion, 11 Heat capacity body, 12 Sealed body, 13 Ribbon wire, 14 Projecting member, 100 Power module.

Claims (8)

A power semiconductor element having a first main surface and a second main surface located opposite to the first main surface;
An electrode formed on the first main surface and having a third main surface;
A conductive member electrically connected to the power semiconductor element;
A wiring portion that electrically connects the power semiconductor element and the conductive member;
A heat capacity body formed on the third main surface of the electrode,
The wiring portion is partly joined to the electrode on the third main surface,
The heat capacity body is a power module formed on a surface region of the third main surface including a joint portion between the electrode and the wiring portion.   The power module according to claim 1, wherein a part of the surface of the part of the wiring portion is exposed from the heat capacity body.   The power module according to claim 1, wherein the part of the wiring portion is embedded in the heat capacity body.   The power module according to any one of claims 1 to 3, wherein the heat capacity body is formed on an entire surface of the third main surface.   The power module according to any one of claims 1 to 3, wherein the heat capacity body is formed on a part of the third main surface.   The power module according to claim 1, wherein the wiring part is a bonding wire.   The power module according to claim 1, wherein the wiring part is a bonding ribbon.   The power module according to any one of claims 1 to 5, wherein the wiring portion is a protruding member made of a conductive material and including a portion protruding from the heat capacity body.

Images