JP3953959B2 - Power semiconductor device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a power semiconductor device, and more particularly to a structure of an electrode connection portion of the power semiconductor device.
[0002]
[Prior art]
A power module in which an insulating substrate mounted with a power semiconductor element such as an IGBT and a control circuit for controlling the power semiconductor element is housed in one case is a power module that inputs and outputs power between the power semiconductor element and the outside. The electrode for performing is provided. The electrode extends from the upper surface of the case to the inside of the case, and is fixed to the insulating substrate disposed on the bottom of the case by solder bonding or wire bond connection.
[0003]
A bus bar, which is an external wiring member, is connected to the electrode on the upper surface of the case, and an upward stress is applied to the electrode during the bus bar wiring. This stress may cause cracking or peeling at the contact surface between the electrode and the insulating substrate. In order to solve this problem, conventionally, a part of the electrode is provided with a lid fitted to at least a part of the upper surface of the case and a protrusion so as to be engaged from below the lid. As a result, the stress related to the electrode (especially upward stress acting during bus bar wiring) is dispersed, and the stress is prevented from acting directly on the contact surface between the electrode and the insulating substrate. In addition to the above, there is one disclosed in Patent Document 1 as a prior art relating to an electrode connection structure in a power semiconductor device.
[0004]
[Patent Document 1]
Japanese Patent Application Laid-Open No. 2002-076255
[Problems to be solved by the invention]
However, in the structure in which the above-described electrode is provided with a protrusion, high accuracy is required in manufacturing the lid and the protrusion. For this reason, if the manufacturing accuracy is low, the protrusions do not function effectively, a direct force acts on the contact surface between the electrode and the insulating substrate, and in some cases, the contact surface may crack or peel off. It was.
[0006]
The present invention has been made to solve the above-mentioned problems, and the object of the present invention is that it can be manufactured without requiring high accuracy, and even when there is a possibility that upward stress is applied to the electrode, such as during bus bar wiring. Another object of the present invention is to provide a power semiconductor device capable of preventing cracking or peeling of a contact surface between an insulating substrate and an electrode.
[0007]
[Means for Solving the Problems]
A power semiconductor device according to the present invention houses a power semiconductor element and its control circuit in a resin case, and an electrode for inputting / outputting power between the power semiconductor element and the outside is provided on the upper end surface of the resin case. This is a power semiconductor device. In the power semiconductor device, a nut is inserted inside the upper end surface of the resin case, and a first bolt provided with a screw hole in the central axis direction is screwed together so as to sandwich the electrode. Further, the external wiring member can be fixed to the first bolt by screwing the second bolt into the screw hole of the first bolt.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of a power semiconductor device according to the present invention will be described below in detail with reference to the accompanying drawings.
[0009]
As shown in FIG. 11, the power module according to the present invention described below is a case in which an insulating substrate 7 on which a power semiconductor element 3 such as an IGBT and a control circuit 5 for controlling the power semiconductor element 3 are mounted is made of resin. 11 is an electric power device housed in 11 and has an electrode 15 extending from the insulating substrate 7 to the upper surface of the case 11 for inputting and outputting electric power between an external power source or an electric device and the electric power semiconductor element.
[0010]
Embodiment 1 FIG.
Fig.1 (a) is the figure which showed the cross section of the electrode connection part vicinity of the power module of Embodiment 1 of this invention. As shown in the figure, a nut 13 is press-fitted into a recess in the upper surface of the side of the case 11. A bolt 17 is screwed into the nut 13.
[0011]
As shown in FIG. 1B, the bolt 17 is formed with a screw hole in the central axis direction. Hereinafter, the bolt 17 in which the screw hole is formed is referred to as a “threaded bolt”. Another bolt 21 is screwed into the screw hole of the threaded bolt 17.
[0012]
Returning to FIG. 1A, an electrode 15 is disposed between the nut 13 and the threaded bolt 17. The electrode 15 is fixed to the upper surface of the case 11 by screwing the threaded bolt 17 with the nut 13. For this reason, the electrode 15 is provided with an opening through which the threaded bolt 17 penetrates.
[0013]
Further, a bus bar 19 is disposed between the bolt 21 and the threaded bolt 17, and the bus bar 19 is fixed by screwing the bolt 21 into the threaded portion of the threaded bolt 17. For this reason, the bus bar 19 is provided with an opening through which the bolt 21 penetrates.
[0014]
Thus, in the power module of this embodiment, the electrode 15 is fixed to the case, and the bus bar 19 is sandwiched and fixed between the two bolts 17 and 21. Thus, by fixing the electrode 15 to the case 11 with the threaded bolt 17 and fixing the bus bar 19 between the two bolts 17 and 21, the upward stress applied to the electrode 15 during bus bar 19 wiring can be reduced. Further, it is possible to prevent the contact surface between the insulating substrate 7 and the electrode 15 from cracking and peeling.
[0015]
Further, since the nut function for fixing the bus bar 19 is included in the threaded bolt 17, no further space for fixing the bus bar 19 is required, and the entire apparatus can be downsized. In this embodiment, since the threaded bolt 17 is in direct contact with the bus bar 19, the threaded bolt 17 is preferably formed of a material having high electrical conductivity.
[0016]
Embodiment 2. FIG.
FIG. 2 shows a second embodiment of the present invention. In the present embodiment, in addition to the configuration of the first embodiment, another nut (hereinafter referred to as “additional nut”) 23 is provided below the nut 13, and the center axis of the opening is the center of the opening of the nut 13. It is press-fitted into the case 11 so as to coincide with the shaft. The additional nut 23 has an opening having a diameter suitable for screwing with the bolt 21, and is screwed with the bolt 21 passing through the bus bar 19 and screwed with the threaded bolt 17. In the present embodiment, since the bolt 21 is also fixed to the case 11, the tightening degree of the bolt 21 is improved.
[0017]
Embodiment 3 FIG.
FIG. 3 shows a third embodiment of the present invention. In the present embodiment, a bolt (hereinafter referred to as “hollow bolt”) 25 having a hollow portion in which no thread is formed is used instead of the threaded bolt 17 in the first and second embodiments. ing. Other configurations are the same as those of the second embodiment. With this configuration, since the hollow bolt 25 and the bolt 21 are not screwed, and the bolt is screwed only with the additional nut 23, the stress applied to the electrode 15 is reduced during wiring of the bus bar 19 and the like, and the present invention is more reliably performed. The purpose will be realized.
[0018]
Embodiment 4 FIG.
FIG. 4 shows a fourth embodiment of the present invention. In the present embodiment, instead of the nut 13 that is screwed with the threaded bolt 17 for fixing the electrode 15 in the first embodiment, a nut that is devised in its shape (hereinafter referred to as a dedicated nut). 27a is used. The dedicated nut 27a can be inserted into the case 11 and is formed so as to collide with the overhang of the opening of the case 11 at least at a part of the upper end surface thereof. As a result, it is possible to reliably prevent the nut 27a from being lifted when the bolt is tightened.
[0019]
Embodiment 5 FIG.
FIG. 5 shows a fifth embodiment of the present invention. In the present embodiment, unevenness is provided in the circumferential direction of the outer peripheral portion of the side surface of the dedicated nut 27 b inserted into the case 11. The dedicated nut 27 b is inserted into the case 11 so that the recess and a part of the case 11 are engaged. The dedicated nut 27b has two screw holes having different diameters so as to be screwed with the second bolt and the hollow bolt 25, respectively. This reliably prevents the nut 27b from lifting when the bolts are tightened. Moreover, since the case 11 has the uneven shape for preventing the lifting, the upper surface of the case 11 does not require a special structure for achieving the purpose. Therefore, the case 11 can be reduced in size.
[0020]
In addition, the exclusive nut 27b in this embodiment may have only one diameter. However, in that case, it is necessary to fix the bolt 21 using the threaded bolt 17 instead of the hollow bolt 25.
[0021]
Embodiment 6 FIG.
FIG. 6 shows a sixth embodiment of the present invention. In the present embodiment, a dedicated nut 27 c is press-fitted into the recess at the upper end of the case 11. Two screw holes having different diameters are provided inside the exclusive nut 27c. The dedicated nut 27c is screwed into the hollow bolt 25 through the upper screw hole, and is screwed into the bolt 21 through the lower screw hole. Instead of the hollow bolt 25, a threaded bolt 17 may be used. By using this single nut 27c, the overall height of the case 11 can be reduced, and the entire apparatus can be reduced in size.
[0022]
Embodiment 7 FIG.
FIG. 7 shows a seventh embodiment of the present invention. In the power module of the present embodiment, the electrode 15 is sandwiched between the U-shaped electrodes 29 having openings on the upper and lower surfaces. FIG. 8 is a perspective view of the vicinity of the U-shaped electrode 29 mounting portion. The threaded bolt 17 penetrates the opening of the U-shaped electrode 29 and is screwed with the nut 13. Thereby, the electrode 15 is fixed. At least the lower end surface of the electrode 15 is in contact with the U-shaped electrode 29, and the U-shaped electrode 29 and the electrode 15 are electrically connected. Therefore, the U-shaped electrode 29 can increase the contact area in the electrical connection between the bus bar 19 and the electrode 15 as compared with the previous embodiment in which the threaded bolt 17 is a conductor. Therefore, even when a large current flows through the electrode, it is possible to suppress the heat generation effect, and the energy loss is smaller than in the previous embodiment. In this embodiment, a hollow bolt 25 may be used instead of the threaded bolt 17.
[0023]
Embodiment 8 FIG.
With reference to FIGS. 9 and 10, an eighth embodiment of the present invention will be described. In the present embodiment, a bolt 18 having a hexagonal hole as a bolt for fixing the electrode and having a circular outer periphery (hereinafter referred to as “hexagonal bolt”) is used. 9). FIG. 10A is a plan view of the hexagon socket bolt 18 and FIG. 10B is a longitudinal sectional view thereof. In FIG. 10A, a hexagon socket 18a of the hexagon socket bolt 18 is an opening for attaching a hexagon wrench during bolt tightening work, and a perfect circle inside thereof indicates an outer periphery of the internal hollow hole 18b. In the example shown in FIG. 8 of the seventh embodiment, the diameter of the opening of the upper end surface of the U-shaped electrode 29 is set to the diameter of the head of the bolt 17 for use of the tightening device when tightening the bolt 17. There was a need to make it even larger. Therefore, the contact area of the electrode with the bus bar or the like has been reduced. Therefore, as shown in FIGS. 9 and 10, the outer periphery of the head of the bolt 18 is formed into a circular shape, and the hexagonal hole is provided in the opening so that the outer diameter of the head of the hexagonal bolt 18 is a U-shaped electrode. 29 can be reduced to the vicinity of the diameter of the opening on the upper end surface. As a result, the contact area between the U-shaped electrode 29 and the bus bar is further increased as compared with the case of the seventh embodiment, and better conductivity is obtained. In addition, although the screw structure is drawn in the internal hole 18b, the internal structure of the hexagonal bolt 18 may not have the screw structure.
[0024]
【The invention's effect】
According to the power semiconductor device of the present invention, it is possible to manufacture without requiring high accuracy, and even when there is a risk that upward stress is applied to the electrode, such as during busbar wiring, cracks on the contact surface between the insulating substrate and the electrode Or peeling can be prevented.
[Brief description of the drawings]
1A is a cross-sectional side view of a case of a power module according to Embodiment 1 of the present invention, and FIG. 1B is a cross-sectional view of a threaded bolt to be used.
FIG. 2 is a cross-sectional view of the vicinity of an electrode connection portion of a power module according to a second embodiment.
FIG. 3 is a cross-sectional view of the vicinity of an electrode connection portion of a power module according to a third embodiment.
FIG. 4 is a cross-sectional view of the vicinity of an electrode connection portion of a power module according to a fourth embodiment.
FIG. 5 is a cross-sectional view of the vicinity of an electrode connecting portion of a power module according to a fifth embodiment.
FIG. 6 is a cross-sectional view in the vicinity of an electrode connection portion of a power module according to a sixth embodiment.
FIG. 7 is a cross-sectional view of the vicinity of a U-shaped electrode connection part according to a seventh embodiment.
FIG. 8 is a perspective view of the vicinity of a U-shaped electrode connection part according to a seventh embodiment.
9 is a perspective view of the vicinity of a hexagon socket head bolt according to an eighth embodiment. FIG.
10A is a plan view of a hexagon socket head bolt, and FIG. 10B is a longitudinal sectional view of the hexagon socket bolt. FIG.
FIG. 11 is a diagram showing an overall configuration of a power module according to the present invention.
[Explanation of symbols]
3 Power Semiconductor Element, 5 Control Circuit, 7 Insulation Base, 11 Case, 13 Nut, 15 Electrode, 17 Threaded Bolt,
18 Hexagon socket head bolt, 19 Busbar, 21 bolt, 23 Additional nut, 25 Hollow bolt, 27 Dedicated nut, 29 U-shaped electrode

Claims (8)

In the power semiconductor device that houses the power semiconductor element and its control circuit in the resin case, and has an electrode on the upper end surface of the resin case for inputting and outputting power between the power semiconductor element and the outside.
A nut inserted inside the upper end surface of the resin case;
A first bolt screwed with the nut to sandwich the electrode and having a screw hole in the central axis direction;
A power semiconductor device comprising: a second bolt capable of fixing an external wiring member between the first bolt by screwing into a screw hole of the first bolt. In the power semiconductor device that houses the power semiconductor element and its control circuit in the resin case, and has an electrode on the upper end surface of the resin case for inputting and outputting power between the power semiconductor element and the outside.
A nut inserted inside the upper end surface of the resin case;
A first bolt sandwiching the electrode between the nut and having a hollow portion in the central axis direction;
A power semiconductor device, comprising: a second bolt capable of fixing an external wiring member between the first bolt by screwing with the nut. 3. The power semiconductor device according to claim 1, wherein the nut has two screw holes that are screwed into the first and second bolts. An additional nut disposed below the nut so that the central axis of the nut opening coincides with the central axis of the opening, and the additional nut is screwed with the second bolt. The power semiconductor device according to claim 1 or 2. 3. The electric power according to claim 1, wherein the nut is inserted into the side of the resin case so that at least a part of the upper end surface of the nut abuts a part of the resin case. Semiconductor device. 2. The nut according to claim 1, wherein the nut has a recess in a part of a side surface thereof, and the nut is inserted into the side of the resin case so that the recess and a part of the resin case are engaged. Or a power semiconductor device according to 2; 3. The U-shaped electrode having openings on the upper surface and the lower surface is further provided, and the ends of the electrodes of the power semiconductor device are sandwiched by using the U-shaped electrode. Power semiconductor devices. The power semiconductor device according to claim 7, wherein the second bolt has a hexagonal hole in a head portion thereof.

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