Power semiconductor device

Abstract

Power semiconductor device comprising: a power semiconductor element; and an element installation ladder that contains: a first conductor section made of metal and used for installing the power semiconductor element, a second conductor section made of metal, forming one or more main terminals for transmitting current to the power semiconductor element and one or more control terminals for transmitting a switching control signal to the power semiconductor element, and a third conductor section, made of metal and located at a tip section of the control terminal, wherein the element installation conductor is formed in such a way that the thickness of a thickest section of the second conductor section is less than the thickness of the first conductor section and that the thickness of a thickest section of the third conductor section is less than the thickness of a thinnest section of the second conductor section.

Description

Technical field

[0001] The present invention relates to a power semiconductor device. State of the art

[0002] As a conventional technology relating to a power semiconductor device, PTL 1, for example, discloses a power module as follows. The power module comprises a semiconductor element, a base section made of a conductive material, a signal line section, and a thin-plate conduction section. The semiconductor element is arranged on the base section. The signal line section is made of the same material as the base section and is electrically connected to the semiconductor element. The thin-plate conduction section is made of the same material as the base section and is formed continuously from the base section. The plate thickness of the thin-plate conduction section is less than that of the base section. The thin-plate conduction section runs along the same side as the signal line section with respect to the base section.The conductor section of a thin plate forms a potential detection terminal, which is electrically connected via the base section to a predetermined terminal of the semiconductor element in order to detect the potential at the predetermined terminal of the semiconductor element. List of oppositions patent literature

[0003] US 2011 / 0310585A1 describes a power module with a main encapsulated body and an auxiliary cast body. It has a module housing. Power semiconductors are enclosed on both sides and held to printed circuit boards. PTL 1: International Publication WO 2012 / 073306A1 Technical problem

[0004] Meanwhile, the power semiconductor device is expected to operate in a vibrating environment. Therefore, a structure is required that ensures, for example, the seismic resistance of a connector for linking the power semiconductor device to the outside. In the conventional technology described above, improved seismic resistance is achieved by enhancing the rigidity of the connector, either by fixing and reinforcing it through resin molding or potting, or by joining it to a single component using TIG (tungsten inert gas) welding or similar processes.

[0005] However, a process such as automated visual inspection is required to ensure the accuracy of the reinforcement when the connection is reinforced by resin molding or potting, thus increasing the man-hours required to assemble the power semiconductor device. Furthermore, a welding process is naturally required if the connection is reinforced by welding or similar methods, again increasing man-hours. Therefore, in conventional technology, there are concerns that increasing the number of processes involved in assembling the power semiconductor device may decrease efficiency. Summary of the invention

[0006] The object of the present invention is to create a power semiconductor device that is able to improve seismic resistance while preventing a reduction in assembly efficiency. Solution to the problem

[0007] The above problem is solved by the features of claim 1. A power semiconductor device has the features of claim 1. It has a power semiconductor element and an element installation conductor comprising a first conductor section made of metal and used for installing the power semiconductor element, a second conductor section made of metal and forming one or more main terminals for transmitting a current to the power semiconductor element and one or more control terminals for transmitting a switching control signal to the power semiconductor element, and a third conductor section made of metal and provided at a tip section of the control terminal.The element installation conductor is formed such that the thickness of the thickest section of the second conductor section is less than the thickness of the first conductor section, and the thickness of the thickest section of the third conductor section is less than the thickness of the thinnest section of the second conductor section. Claim 1 specifies further features. Advantageous effects of the invention

[0008] According to the present invention, it is possible to create a power semiconductor device that is able to improve seismic resistance while preventing a reduction in assembly efficiency. Brief description of the drawings Fig. Figure 1 is a representation that schematically depicts the appearance of a power semiconductor device according to a first embodiment. Fig. 2 is a cross-sectional view along line A in Fig. 1. Fig. Figure 3 is a representation depicting an extracted element installation conductor. Fig. Figure 4 is a representation that depicts a form in which a main terminal and a control terminal are connected by a connecting rail. Fig. Figure 5 is an enlarged view showing a shape between connectors in Fig. 1 represents. Fig. Figure 6 is a representation that schematically depicts the appearance of the power semiconductor device according to an example modification of the first embodiment. Description of embodiments

[0009] The following describes an embodiment of the present invention with reference to the drawings. <Erste Ausführungsform>

[0010] Based on the Fig. Sections 1 to 4 describe a first embodiment of the present invention.

[0011] Fig. Figure 1 is a schematic representation of the appearance of a power semiconductor device according to the present embodiment. Fig. 2 is a cross-sectional view along line A in Fig. 1. Furthermore, Fig. 3 a representation that shows one from Fig. 1 and Fig. 2 extracted element installation conductors. It is noted that the tip sections of the main connection and the control connection in Fig. 3 are not shown for the sake of simplicity.

[0012] A power semiconductor device 1 in Fig. 1 to 3 includes at least one power semiconductor element 300 (hereinafter represented by reference numeral 300) containing an IGBT (insulated-layer bipolar transistor) 30, a diode 31, and the like, and an element installation conductor 2 comprising a first conductor section 20a, a second conductor section 20b, and a third conductor section 20c. The first conductor section 20a is made of metal and is used for mounting the power semiconductor element 300. The second conductor section 20b is made of metal and forms one or more main terminals 20a for transmitting current to the power semiconductor element 300 and one or more control terminals 2b for transmitting a switching control signal to the power semiconductor element 300. The third conductor terminal 20c is made of metal and is provided at the tip section of the control terminal.

[0013] The element installation conductor 2 refers to a conductor frame or busbar component made of copper (Cu) or a copper alloy. The element installation conductor 2 is designed such that the thickness of the thickest section of the second conductor section 20b is less than the thickness of the first conductor section 20a, and the thickness of the thickest section of the third conductor section 20c is less than the thickness of the thinnest section of the second conductor section 20b. That is, the element installation conductor 2 is designed such that it gradually decreases in thickness from the first conductor section 20a to the tips of the main terminal 2a and the control terminal 2b.

[0014] It is noted that the present embodiment describes an example in which, with respect to the three sections, which are the first conductor section 20a, the second conductor section 20b, and the third conductor section 20c, the thickness decreases in three steps from the first conductor section 20a to the third conductor section 20c. The embodiment is not limited to this, and the three sections can be configured such that the thickness decreases in three or more steps towards the tips. That is to say, the second conductor section 20b, for example, can be formed with two types of thickness that decrease towards the tip in such a way that they become smaller than the first conductor section 20a and smaller than the third conductor section 20c.

[0015] Furthermore, in the power semiconductor device 1, the entirety of the first conductor section 20a and a section of the second conductor section 20b is covered by a housing 4, which includes a frame body 21a and a heat dissipation fin assembly 21b. The entirety of the first conductor section 20a and the section of the second conductor section 20b, together with the power semiconductor element 300 and the like, is injection-molded and sealed in the housing 4 by a potting resin 22, which, for example, contains an epoxy resin.

[0016] The housing 4 is made of a material with excellent thermal conductivity and is preferably, for example, made of aluminum or an aluminum alloy. Furthermore, the frame body 21a is made of a material with higher rigidity than the heat dissipation fin group 21b. Although Fig. While Figure 1 shows only one main surface of the housing 4 for the sake of clarity, it should be noted that the heat dissipation fin group 21b is configured on both main surfaces of the housing 4 to create a double-sided cooling structure. The heat dissipation fins forming the heat dissipation fin group 21b are, for example, arranged in a columnar shape and in a regular pattern.

[0017] The power semiconductor element 300, which contains the IGBT 30, the diode 31 and the like, is mounted on the first conductor section 20a of the element installation conductor 2 using solder, a sintered component or the like. The first conductor section 20a serves as a conduction path for the main current and as a heat dissipation path for dissipating heat from the power semiconductor element 300 to the outside of the power semiconductor device 1.

[0018] The power semiconductor element 300 is positioned between the first conductor section 20a and a printed circuit board 32. The printed circuit board 32 serves as the heat dissipation path for the power semiconductor element 300. Furthermore, for example, an emitter electrode of the IGBT 30 and an anode electrode of the diode 31 are fixed to the printed circuit board 32. It is noted that a section or the entirety of the first conductor section 20a can be subjected to a surface treatment (roughening treatment) to improve adhesion with the potting resin 22.

[0019] The main terminal 2a of the element installation conductor 2 is a supply path for the main current between the outer space of the power semiconductor device 1 and the power semiconductor element 300. The main terminals 2a include a positive DC electrode terminal, a negative DC electrode terminal, an AC terminal, and the like. The main terminal 2a is formed by the second conductor section 20b, which is thinner than the first conductor section 20a. It is noted that a section or the entirety of the second conductor section 20b of the main terminal 2a is subjected to a surface treatment (roughening treatment) to improve adhesion with the potting resin 22.

[0020] The control terminal 2b of the element installation conductor 2 is a signal path for inputting and outputting a signal to control the power semiconductor element. The control terminal 2b is formed by the second conductor section 20b, which is thinner than the first conductor section 20a, and by the third conductor section 20c, which is thinner than the second conductor section 20b. The tip of the control terminal 2b is connected to a control board (not shown) by a soldered connection, a connector connection, or the like. It should be noted that the tip (the third conductor section 20c) of the control terminal 2b is subjected to a surface treatment, such as tin plating or gold plating, according to the connection structure with the control board.

[0021] Furthermore, each terminal of the control terminal 2b is provided with a bent section (first bent section) 2c, which is formed such that a section of the third conductor section 20c deviates from a given direction. Thus, by changing the elasticity of the bent section 2c, it is possible to reduce the mechanical stress caused by vibration and thermal deformation. It is noted that the control terminals 2b include a terminal for outputting a signal indicating the element temperature. Furthermore, the curvature R of the bent section (first bent section) 2c is preferably equal to or greater than the plate thickness of a section on which the bent section 2c is provided. In addition, the present embodiment describes, as an example, a case in which the bent section (first bent section) 2c is provided in the third conductor section 20c.The embodiment is not limited to this and, for example, a configuration can be produced in which the bent section is provided in the second conductor section.

[0022] An example of the thickness of the first conductor section 20a to the third conductor section 20c is described here. The first conductor section 20a is formed, for example, with a thickness of 2.0 mm, taking into account the heat capacity and thermal resistance required to dissipate the heat generated by the power semiconductor element 300. The second conductor section 20b of the main terminal 2a is formed, for example, with a thickness of 1.5 mm to 2.0 mm (less than 2.0 mm), as thick as the cross-sectional area required to ensure the power supply. The third conductor section 20c of the control terminal 2b is thinner than the second conductor section 20b and is formed, for example, with a thickness of 0.64 mm, which is the same as that of the control terminal. Since the transverse dimension (i.e.,where the width) of the control terminal 2b is generally formed as 0.64 mm, the third conductor section 20c of the control terminal 2b is formed with a square shape in which one side of the cross-section is 0.64 mm.

[0023] The main terminal 2a and the control terminal 2b are formed in the same direction from the potting resin 22. The side surface of the second conductor section 20b of the main terminal 2a faces the side surface of the second conductor section 20b of the control terminal 2b. Furthermore, the main terminal 2a is formed by the second conductor section 20b and does not have the third conductor section 20c. The main terminal 2a and the control terminal 2b are then formed such that only the side surfaces of the second conductor sections 20b of the main terminal 2a and the control terminal 2b face each other, and that the side surface of the second conductor section 20b of the main terminal 2a does not face the side surface of the third conductor section 20c of the control terminal 2b. That is, the control terminal 2b is longer than the main terminal 2a by the length of the third conductor section 20c.This makes it possible to set the length of control terminal 2b to be greater than the length of main terminal 2a. This makes it possible to prevent interference between main terminal 2a and the control board, insufficient insulation distance, or similar issues when control terminal 2b is connected to the control board.

[0024] Fig. Figure 4 is a representation that depicts a form in which the main terminal and the control terminal are connected by a connecting rail. Furthermore, Fig. 5 an enlarged view showing a shape between the connections in Fig. 1 represents.

[0025] As in Fig. As shown in Figure 5, a cross-sectional area 201a of a connecting rail 200a is formed at the opposite section of the side surface of the second conductor section 20b of the main connection 2a, at the opposite section of the side surface of the second conductor section 20b of the control connection 2b, or at the opposite sections of the side surface of the second conductor section 20b of the main connection 2a and the side surface of the second conductor section 20b of the control connection 2b.

[0026] As in Fig. As shown in Figure 4, the connecting rail 200a fixes the relative positions of the main terminal 2a and the control terminal 2b on the element installation conductor 2 before it is injection-molded and sealed with the potting resin 22. The connecting rail 200a also prevents the potting resin 22 from flowing out of the spaces between the terminals of the main terminal 2a and between the terminals of the control terminal 2b. After the relative positions of the main terminal 2a and the control terminal 2b have been fixed in the element installation conductor 2 by the potting resin 22, the connecting rail 200a is cut out and removed, so that the terminals of the main terminal 2a and the terminals of the control terminal 2b are electrically isolated from each other.

[0027] This means that it is conceivable that the second conductor section 20b of the main terminal 2a and the second conductor section 20b of the control terminal 2b are formed in one piece by the connecting rail. Thus, considering the advantages of the one-piece formation, the thickness of the second conductor section 20b of the main terminal 2a is preferably equal to the thickness of the second conductor section 20b of the control terminal 2b. It is noted that the cross-sectional surface with respect to the side surface of each terminal can have either a convex or a concave shape, with the convex shape being preferred from the point of view of ensuring the connection strength.

[0028] The effects of the present embodiment configured as described above are described.

[0029] Since the power semiconductor device is expected to operate in a vibrating environment, a structure ensuring the seismic resistance of the connection between the power semiconductor device and the outside is required. Conventional technology improves seismic resistance by increasing the rigidity of the connection, either by fixing and reinforcing it through resin molding or potting, or by joining it to a single component using TIG (tungsten inert gas) welding or similar processes. However, when reinforcing the connection through resin molding or potting, a process such as automated visual inspection is required to ensure the accuracy of the reinforcement, thus increasing the man-hours needed to assemble the power semiconductor device.Furthermore, a welding process is naturally required if the connection is reinforced by welding or similar methods, thus increasing man-hours. This means that in conventional technology, there are concerns that efficiency may decrease due to the increased number of processes involved in assembling the power semiconductor device.

[0030] On the other hand, in the present embodiment, the power semiconductor device includes the power semiconductor element 300 and the element installation conductor 2, which includes the first conductor section 20a, which is made of metal and is used for installing the power semiconductor element 300, the second conductor section 20b, which is made of metal and forms one or more main terminals 2a for transmitting a current to the power semiconductor element 300 and one or more control terminals 2b for transmitting a switching control signal to the power semiconductor element 300, and the third conductor section 20c, which is made of metal and is provided at the tip section of the control terminal 2b.In the power semiconductor device 1, the element installation conductor 2 is formed in such a way that the thickness of the thickest section of the second conductor section 20b is less than the thickness of the first conductor section 20a and that the thickness of the thickest section of the third conductor section 20c is less than the thickness of the thinnest section of the second conductor section 20b.

[0031] This makes it possible to improve the strength (rigidity) of each connection and enhance seismic resistance, while preventing a reduction in assembly efficiency. In other words, it is possible to improve the reliability and lifetime of the power semiconductor device as a product.

[0032] Since the thickness of the second conductor section 20b is less than the thickness of the first conductor section 20a, and since the thickness of the third conductor section 20c is less than the thickness of the second conductor section 20b, it is also possible to integrate the entire element installation conductor 2 configured by the first conductor section 20a to the third conductor section 20c with a copper (Cu) material (e.g., rolled material). This makes it possible to reduce the number of components and eliminate the need for sealing in a separate process.

[0033] Furthermore, it is assumed that the third conductor section 20c has the first curved section which is formed in such a way that it deviates from the direction of travel of the third conductor section 20c.

[0034] This makes it possible to buffer deformation and mechanical stress caused by vibration and heat. Accordingly, it is possible to relieve mechanical stress at a connection point by soldering, using a connector, or by press-fitting between the tip of control terminal 2b and the control board, thus preventing damage to the terminal or breakage of a contacted section.

[0035] Furthermore, it is assumed that the main connection 2a is formed by the second conductor section 20b, that the control connection 2b is formed by the second conductor section 20b and by the third conductor section 20c, and that the side surface of the second conductor section 20b of the main connection 2a faces the side surface of the second conductor section 20b of the control connection 2b.

[0036] Thus, the control terminal 2b is longer than the main terminal 2a by the length of the third conductor section 20c. This makes it possible to prevent interference between the main terminal 2a and the control board, insufficient insulation distance, or similar issues when the control terminal 2b is connected to the control board.

[0037] Furthermore, it is assumed that the potting resin 22 is intended to seal the entirety of the first conductor section 20a and the section of the second conductor section 20b, and that the main connection 2a and the control connection 2b are formed protruding from the potting resin 22 in the same direction.

[0038] Thus, it is possible to align the protruding terminals in a single direction, thereby reducing the size of the power semiconductor device 1 compared to cases where the terminals protrude in multiple directions. Furthermore, aligning the protruding terminals in the same direction allows for a single connection direction when the power semiconductor device 1 is connected to the control board of an inverter device or the like. This simplifies the process considerably compared to multidirectional connections. Additionally, in a water-cooling process, it is possible to establish a single sealing point, simplify the sealing structure, and reduce the number of sealing elements.

[0039] Furthermore, it is assumed that the intersection surface 201a of the connecting rail 200a is formed on the opposite sections of the side surfaces of the second conductor section 20b of the main terminal 2a and the control terminal 2b to fix the relative positions of the main terminal 2a and the control terminal 2b.

[0040] This makes it possible to improve the strength (rigidity) of each connection and enhance seismic resistance, while preventing a reduction in assembly efficiency. In other words, it is possible to improve the reliability and lifetime of the power semiconductor device as a product. <Geändertes Beispiel der ersten Ausführungsform>

[0041] Based on Fig. Section 6 describes an example of an amendment to the first embodiment of the present invention. In this example, only the differences from the first embodiment are described, and components similar to those in the first embodiment are designated in the drawings by the same reference numerals, and their descriptions are omitted.

[0042] The present modification example describes a case in which a second bent section is formed in the second conductor section.

[0043] Fig. Figure 6 is a schematic representation of the appearance of a power semiconductor device according to the present modification example.

[0044] In Fig. 6 includes a power semiconductor device 1A, an element installation conductor 2A, which has a first conductor section 20a made of metal and used for installing at least one power semiconductor element 300 (see Fig. 2 and the like), a second conductor section 201b, which is made of metal and forms one or more main terminals 2Aa for transmitting a current to the power semiconductor element 300 and one or more control terminals 2Ab for transmitting a switching control signal to the power semiconductor element 300, and a third conductor section 20c, which is made of metal and is provided at a tip section of the control terminal 2Ab.

[0045] Furthermore, the second conductor section 201b is connected to a second curved section 2d, which protrudes from the potting resin 22 in one direction (in Fig. 6 is bent upwards).

[0046] Other components are similar to those in the first embodiment.

[0047] In the present embodiment configured as described above, it is also possible to obtain similar effects as in the first embodiment.

[0048] Since the main terminal 2Aa and the control terminal 2Ab are bent at a predetermined angle to change the direction of protrusion, it is also possible to establish a connection with the control board even though the power semiconductor device 1A is mounted flat. Furthermore, the provision of the second bent section 2d makes it possible to reduce the linear lengths of the main terminal 2Aa and the control terminal 2Ab, thereby reducing displacement due to vibration and improving vibration resistance. <anhang>

[0049] Furthermore, the present embodiment illustrates and describes the case in which the first conductor section 20a, the second conductor section 20b, and the third conductor section 20c are integrated. For example, the first conductor section 20a and the second conductor section 20b can be formed separately from each other and electrically connected by wire contacts or the like. Reference symbol list 1.1A Power semiconductor device 2 element installation ladders 2A, 2Aa main connection 2A Element installation conductor 2b, 2Ab Control connection 2c curved section (first curved section) 2d second curved section 4 cases 20a first ladder section 20b second ladder section 20c third ladder section 21a Frame body 21b Heat dissipation fin group 22 Potting resin 31 Diode 32 circuit boards 200a connecting rail 201a Cut surface 201b second ladder section 300 power semiconductor element< / anhang>

Claims

[1] Power semiconductor device comprising: a power semiconductor element; and an element installation ladder that contains: a first conductor section made of metal and used for installing the power semiconductor element, a second conductor section made of metal, forming one or more main terminals for transmitting current to the power semiconductor element and one or more control terminals for transmitting a switching control signal to the power semiconductor element, and a third conductor section, made of metal and located at a tip section of the control terminal, wherein the element installation conductor is formed in such a way that the thickness of a thickest section of the second conductor section is less than the thickness of the first conductor section and that the thickness of a thickest section of the third conductor section is less than the thickness of a thinnest section of the second conductor section. [2] Power semiconductor device according to claim 1, wherein the third conductor section has a first curved section which is formed in a direction different from that of the third conductor section. [3] Power semiconductor device according to claim 1, wherein the main connection is formed by the second conductor section and the control connection is formed by the second conductor section and by the third conductor section, and a side surface of the second conductor section of the main connection is formed facing a side surface of the second conductor section of the control connection. [4] Power semiconductor device according to claim 1, wherein a potting resin is arranged to seal the entirety of the first conductor section and a section of the second conductor section, and The main connection and the control connection are formed from the potting resin protruding in the same direction. [5] Power semiconductor device according to claim 4, wherein the second conductor section has a second bent section which is bent in a direction of protrusion from the potting resin. [6] Power semiconductor device according to claim 1, wherein on each of the opposite sections of the side surfaces of the second conductor section of the main terminal and the second conductor section of the control terminal a cross-sectional surface of a connecting rail is formed for fixing relative positions of the main terminal and the control terminal.

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