External connectors and their manufacturing methods, semiconductor modules, vehicles, and connection methods.

Abstract

This invention provides an external connection portion for a semiconductor module that improves the reliability of external connections. An external connection portion (20) for a semiconductor module is provided. The external connection portion (20) according to an embodiment of this invention has an external connection terminal (25) and a nut (40) disposed on one side of the lower surface of the external connection terminal (25). The external connection terminal (25) has a conductor (60), a first metal layer (71) disposed on the upper surface (62) of the conductor (60), a second metal layer (72) disposed on the first metal layer (71), and a lower surface metal layer (73) disposed on the lower surface (64) of the conductor (60).

Description

Technical Field

[0001] The present invention relates to an external connection part of a semiconductor module, a method for manufacturing the external connection part of a semiconductor module, a semiconductor module, a vehicle, and a connection method between the external connection part and a busbar. Background Technology

[0002] Previously, it was known that semiconductor modules could be connected to the outside via external connection terminals and input or output main power (for example, see Patent Document 1).

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2010-098036 Summary of the Invention

[0006] Technical issues

[0007] According to embodiments of the present invention, an external connection portion of a semiconductor module is provided to improve the reliability of external connections.

[0008] Technical solution

[0009] To address the aforementioned technical problems, a first embodiment of the present invention provides an external connection portion for a semiconductor module. The external connection portion is an external connection portion of a semiconductor module having an external connection terminal and a nut disposed on the lower surface side of the external connection terminal. The external connection terminal has a conductor, a first metal layer disposed on the upper surface of the conductor, a second metal layer disposed on the first metal layer, and a lower surface metal layer disposed on the lower surface of the conductor.

[0010] The first metal layer can have a higher hardness than the second metal layer.

[0011] The first metal layer can be formed of the same material as the lower surface metal layer.

[0012] The conductor may have a thickness of 1.0 mm or more and 7.0 mm or less, the first metal layer may have a thickness of 0.1 μm or more and 10 μm or less, the second metal layer may have a thickness of 0.1 μm or more and 10 μm or less, and the lower surface metal layer may have a thickness that is the same as or greater than that of the first metal layer.

[0013] The conductor is formed of copper or a copper alloy, the first metal layer and the lower surface metal layer are bright nickel layers, and the second metal layer is a gold layer, a matte nickel layer, a copper-tin alloy layer or a silver layer.

[0014] The second metal layer can be configured to cover a portion of the first metal layer.

[0015] The outer diameter of the nut can be the same as or smaller than the maximum diameter of the screw corresponding to the nut.

[0016] The nut can be integrated with the housing of the semiconductor module.

[0017] The nut can be a flange nut with a flange on the side of the external connection terminal.

[0018] In a second embodiment of the present invention, a method for manufacturing an external connection portion of a semiconductor module is provided. The manufacturing method includes the steps of providing an external connection terminal and providing a nut on one side of the lower surface of the external connection terminal. The step of providing the external connection terminal includes: providing a conductor; providing a first metal layer on the upper surface of the conductor; providing a second metal layer on the first metal layer; and providing a lower surface metal layer on the lower surface of the conductor.

[0019] The step of providing an external connection terminal may include forming an external connection terminal having a protruding shape that protrudes from one side of the upper surface.

[0020] In a third embodiment of the present invention, a semiconductor module is provided. The semiconductor module includes the external connection portion of the first embodiment of the present invention.

[0021] In a fourth embodiment of the present invention, a vehicle is provided. The vehicle includes a semiconductor module according to a third embodiment of the present invention.

[0022] In a fifth embodiment of the present invention, a connection method between an external connecting portion and a busbar is provided. The connection method includes: a step of arranging the busbar on one side of the upper surface of the external connecting terminal; a step of inserting the bolt portion of a screw into the hole of the busbar and the threaded hole of the external connecting terminal; and a step of embedding the end of a nut into the lower surface metal layer by screwing in the screw.

[0023] It should be noted that the above description of the invention does not list all the necessary features of the invention. Furthermore, sub-combinations of these feature groups can also constitute an invention. Attached Figure Description

[0024] Figure 1A This is a schematic view of the upper surface of the semiconductor module 100 according to an embodiment of the present invention.

[0025] Figure 1B This is an enlarged view of the upper surface of the external connection portion 20 according to an embodiment of the present invention.

[0026] Figure 1C This is a cutaway view of the external connection portion 20 according to an embodiment of the present invention.

[0027] Figure 1DThis is a cross-sectional view of the external connection portion 20 according to an embodiment of the present invention.

[0028] Figure 2 This is a cross-sectional view of the external connection part 320 of the reference example.

[0029] Figure 3 This is a top surface view showing another example of the external connection portion 20 according to an embodiment of the present invention.

[0030] Figure 4 This is a cutaway view showing another example of the external connection portion 20 according to an embodiment of the present invention.

[0031] Figure 5 This is an explanatory diagram showing a method for manufacturing the external connection portion 20 according to an embodiment of the present invention.

[0032] Figure 6 This is a schematic diagram of a vehicle 200 according to an embodiment of the present invention.

[0033] Figure 7 This is a main circuit diagram of the semiconductor module 100 according to an embodiment of the present invention.

[0034] Symbol Explanation

[0035] 10… Semiconductor unit, 12… Semiconductor chip, 20… External connection part, 25… External connection terminal, 28… Threaded hole, 30… Busbar, 32… Screw, 34… Screw head, 36… Bolt part, 40… Nut, 42… Nut hole, 44… End, 50… Housing, 51… Reception part, 55… Resin, 60… Conductor, 62… Upper surface, 64… Lower surface, 71… First metal layer, 72… Second metal layer, 73… Lower surface metal layer, 78… First semiconductor chip, 79… Second semiconductor chip, 80… Semiconductor chip, 90… Base plate, 92… Insulating plate, 94… Circuit layer, 93… Conductive component, 100… Semiconductor module, 200… Vehicle, 210… Control device, 320… External connection part, 325… External connection terminal. Detailed Implementation

[0036] The present invention will now be described through embodiments thereof, but these embodiments do not limit the invention as defined in the claims. Furthermore, not all combinations of the features described in the embodiments are necessarily required for the solution of the invention.

[0037] In this specification, one side in the direction parallel to the depth direction of the semiconductor module is referred to as "upper" and the other side as "lower". Of the two main surfaces of a substrate, layer, or other component, one surface is called the upper surface and the other surface is called the lower surface. The "upper" and "lower" directions are not limited to the direction of gravity or the mounting direction of the semiconductor chip towards the substrate, etc.

[0038] Figure 1A This is a schematic diagram showing the upper surface of a semiconductor module 100 according to an embodiment of the present invention. The semiconductor module 100 includes a housing 50, a semiconductor unit 10 housed within the housing 50, and an external connection portion 20. In this specification, [the following will be used to describe the semiconductor module 100]. Figure 1A In a top-down view, the long side of the rectangular housing 50 is designated as the X-axis, and the short side as the Y-axis. For example, the semiconductor module 100 is an intelligent power module (IPM). Furthermore, the direction on the side of the semiconductor module 100 containing the semiconductor unit 10 is designated as the Z-axis, which forms a right-hand rule with the X and Y axes. "Top-down view" refers to viewing the semiconductor module 100 from the positive direction along the Z-axis.

[0039] Semiconductor unit 10 is an assembly comprising an insulating substrate and a plurality of semiconductor chips 12 disposed on the insulating substrate. The insulating substrate may include an insulating plate 92 and a circuit layer 94. Semiconductor unit 10 may further include conductive components 93. Conductive components 93 are, for example, wires, ribbons, or clips. The insulating plate 92, circuit layer 94, and semiconductor chips 12 may be sequentially arranged in the Z-axis direction. Semiconductor chips 12 have switching elements such as metal-oxide-semiconductor field-effect transistors (MOS-FETs), insulated-gate bipolar transistors (IGBTs), and reverse-conducting IGBTs (RC-IGBTs). A reverse-conducting IGBT (RC-IGBT) is a component that includes an IGBT and a freewheeling diode (FWD) on the same chip. Furthermore, semiconductor module 100 may be a three-phase converter module having U-phase, V-phase, and W-phase. The circuit layer 94, semiconductor chip 12, and conductive component 93 in semiconductor unit 10 can be electrically connected to form a half-bridge circuit. The circuit layer 94 can be electrically connected to the external connection part 20.

[0040] The external connection section 20 can input or output the main current of the semiconductor module 100. The external connection section 20 is electrically connected to the semiconductor chip 12. Whether the external connection section 20 outputs or inputs current depends on the intended use of the semiconductor module 100 and is not limited by anything else. When the semiconductor module 100 is a three-phase converter module, the external connection section 20 inputs or outputs currents for driving the U-phase, V-phase, and W-phase, respectively. The external connection section 20 can function as a power supply terminal or a load terminal. The size or shape of the external connection section 20 as a power supply terminal and the external connection section 20 as a load terminal can be different.

[0041] The housing 50 is molded from a thermosetting resin that can be formed by injection molding, or an ultraviolet-curable resin that can be formed by UV molding, and so on. The resin used to mold the housing 50 includes one or more polymeric materials selected from, for example, polyphenylene sulfide (PPS) resin, polybutylene terephthalate (PBT) resin, polyamide (PA) resin, acrylonitrile-butadiene-styrene copolymer (ABS) resin, and acrylic resin.

[0042] The base plate 90 is disposed below the insulating substrate on which the semiconductor chip 12 is disposed. The base plate 90 may be a plate-shaped metal plate having a plane parallel to the XY plane. As an example, the base plate 90 is formed of a metal including aluminum, copper, etc.

[0043] As an example, the insulating substrate may be a laminated substrate comprising, in sequence, an insulating plate 92 having an upper surface and a lower surface, a circuit layer 94 disposed on the upper surface of the insulating plate 92, and a metal layer (not shown) disposed on the lower surface. The insulating substrate may be, for example, a DCB (Direct Copper Bonding) substrate or an AMB (Active Metal Brazing) substrate. The insulating plate 92 may be formed using ceramic materials such as alumina (Al2O3), aluminum nitride (AlN), or silicon nitride (Si3N4). The circuit layer 94 and the metal layer may be plates containing conductive materials such as copper or copper alloys.

[0044] Figure 1B This is an enlarged view of the upper surface of the external connection portion 20 according to an embodiment of the present invention. Specifically, Figure 1B The external connection section 20 is shown when externally connected. The external connection section 20 is externally connected via the busbar 30, allowing current input and output to the outside. "When externally connected" means that the external connection section 20 and the busbar 30 overlapping the external connection section 20 are tightened together by screws 32. The external connection section 20 is surrounded by a housing 50.

[0045] Busbar 30 is a plate-shaped conductor. Busbar 30 can be a plate-shaped component made of a conductive metal such as copper or a copper alloy. In this example, busbar 30 can be shaped to cover the entire external connection portion 20 when viewed from above. The size of busbar 30 when viewed from above is not limited to this, as long as it is large enough to be tightened together with screws 32.

[0046] As an example, busbar 30 has a thickness of 5 mm or more. Busbar 30 with this thickness can supply power even when the semiconductor module 100 is a power module using a high current of 1200A or more.

[0047] Screw 32 tightens the external connecting part 20 and the busbar 30 together. Screw 32 has a screw head 34 and a bolt part 36. As an example, in top view, the screw head 34 has a circular shape. However, the shape of the screw head 34 is not limited to a circle, and can also be a hexagon or other polygonal structure. The screw head 34 is provided with a cross-shaped groove. The type of groove provided on the screw head 34 is not limited to a cross-shaped groove. As an example, the screw 32 can be an M4 screw to an M6 screw. The screw 32 can be formed of a metal selected from alloys of iron, copper, aluminum, etc., or it can be formed of reinforced plastic.

[0048] Figure 1C This is a cutaway view of the external connection portion 20 according to an embodiment of the present invention. Figure 1C In the middle, busbar 30 and screw 32 are also shown together with external connection part 20.

[0049] The external connection portion 20 includes an external connection terminal 25 and a nut 40 disposed on the lower surface side of the external connection terminal 25. The external connection terminal 25 includes a conductor 60, a first metal layer 71 disposed on the upper surface 62 of the conductor 60, a second metal layer 72 disposed on the first metal layer 71, and a lower surface metal layer 73 disposed on the lower surface 64 of the conductor 60. In other words, in the external connection terminal 25, the outer surface of the second metal layer 72 corresponds to the mating surface that engages with the busbar 30, and the outer surface of the lower surface metal layer 73 corresponds to the mating surface that engages with the nut 40. Furthermore, the external connection terminal 25 has a threaded hole 28 extending through it.

[0050] In this example, the external connection terminal 25 can have a flat shape in the XY plane or a protruding shape towards the upper surface of the external connection terminal 25. If the external connection terminal 25 is protruding, then during external connection, the busbar 30 contacts the second metal layer 72 in the peripheral region of the threaded hole 28, and the nut 40 contacts the lower surface metal layer 73 at the end 44 (described later). For example, the protruding external connection terminal 25 may have a maximum radius of curvature of 200 μm.

[0051] Conductor 60 is formed of a conductive material. For example, conductor 60 contains copper or a copper alloy. Conductor 60 may be formed from a plate containing copper or a copper alloy.

[0052] The conductor 60 is configured with a thickness that is sufficiently robust to withstand buckling caused by the tightening torque from the nut 40 and screw head 34. Furthermore, the conductor 60 is configured with a thickness that allows sufficient current to flow from the external connection terminal 25 to the semiconductor module 100. For example, the thickness of the conductor 60 from the upper surface 62 to the lower surface 64 is 1.0 mm or more and 7.0 mm or less.

[0053] As described above, the thickness of conductor 60 is set according to the rigidity and conductivity of the material selected as conductor 60. When other materials are used for conductor 60, the thickness of conductor 60 can be set differently depending on the physical properties of the material used.

[0054] The first metal layer 71 is formed of a material with high hardness. The first metal layer 71 has a higher hardness than the second metal layer 72. As an example, the first metal layer 71 is a glossy nickel plating mainly formed of nickel. When using a nickel plating, a plating that is dirt-resistant, compositionally stable, corrosion-resistant, and has high hardness and is difficult to scratch can be provided at a low cost. In this example, the first metal layer 71 covers the entire upper surface 62 of the conductor 60. As an example, the first metal layer 71 has a thickness of 0.1 μm or more and 10 μm or less.

[0055] The second metal layer 72 forms a mating surface with the busbar 30 on one side of the upper surface of the external connection terminal 25. In this example, the second metal layer 72 is formed of a material with a lower hardness than the first metal layer 71. As an example, the second metal layer 72 is a gold layer, a matte nickel layer, a copper-tin alloy layer, or a silver layer. Therefore, during external connection, the contact resistance between the external connection terminal 25 and the busbar 30 can be reduced. In this example, the second metal layer 72 covers the entire upper surface of the first metal layer 71. As an example, the second metal layer 72 has a thickness of 0.1 μm or more and 10 μm or less.

[0056] The lower surface metal layer 73 forms a nut surface on one side of the lower surface of the external connection terminal 25. The lower surface metal layer 73 is formed of the same material as the first metal layer 71. Therefore, the lower surface metal layer 73 has a higher hardness than the second metal layer 72. In this example, the lower surface metal layer 73 covers the entire lower surface 64 of the conductor 60. As an example, the lower surface metal layer 73 is a glossy nickel plating mainly formed of nickel.

[0057] The thickness of the lower surface metal layer 73 is set to allow for the insertion of the nut 40 during external connection. The lower surface metal layer 73 has the same thickness as the first metal layer or a thickness greater than the first metal layer. As an example, the lower surface metal layer 73 has a thickness of 0.1 μm or more and 10 μm or less. Preferably, the lower surface metal layer 73 has a thickness of 1 μm or more and 3 μm or less.

[0058] The following describes metal layers applicable to the first metal layer 71, the second metal layer 72, and the lower surface metal layer 73. Each metal layer can be formed by a known electroplating method. Each metal layer may contain unavoidable impurities, in addition to the additives described later.

[0059] (1) Glossy nickel layer

[0060] In this example, the glossy nickel layer can be a glossy nickel plating. For example, a glossy nickel plating is formed by electroplating. Electroplating sequentially includes a cleaning process, a substrate electroplating process with a film thickness of less than 0.5 μm, an electroplating process, and a cleaning process.

[0061] As an example, the main components of the electroplating solution include nickel sulfate, nickel chloride, and boric acid. Additives include primary brighteners containing sulfur-based components such as saccharin and sodium naphthalene disulfonate, and secondary brighteners containing unsaturated alcohols such as butynediol, propargyl alcohol, and coumarin. The hardness of the film can be adjusted according to the brightener, with an HV (Vickers hardness) value of 400–600.

[0062] (2) Matte nickel layer

[0063] In this example, the matte nickel layer can be a matte nickel plating. Typically, matte nickel plating differs from glossy nickel plating in that it is formed using an electroplating solution without brighteners. It should be noted that a semi-gloss nickel plating formed using an electroplating solution containing a small amount of brightener can be used instead of a typical matte nickel layer. In this case, the film hardness can be adjusted to an HV (Vickers hardness) value of 200–300 depending on the brightener used.

[0064] (3) Copper-tin alloy layer

[0065] In this example, the copper-tin alloy layer can be formed by heat treatment of the stacked copper and tin layers. The copper and tin layers can be formed sequentially on top of the matte nickel plating from the base material side. The matte nickel plating as the substrate can be formed according to the method described above. The copper plating is an electroplated layer of copper cyanide, copper sulfate, or copper pyrophosphate. The tin plating is formed using an alkaline plating bath, a methanesulfonic acid plating bath, a sulfuric acid plating bath, or a neutral plating bath (carboxylic acid plating bath).

[0066] After electroplating, a heat treatment is performed at 150–200℃ for 1 hour to form a copper-tin alloy plating layer. The film hardness is HV value 300–600, and the maximum film thickness is matte nickel layer / copper layer / tin layer = 2μm / 0.3μm / 0.5μm.

[0067] (4) Gold layer

[0068] In this example, the gold layer can be a gold plating. For instance, the gold plating can be formed by an electroless plating method. The plating bath is an alkaline bath with potassium gold cyanide as the main component, serving as the gold ion supply source. Alternatively, the plating bath can be an acidic bath with citric acid or phosphoric acid as the main components. A trace amount of cobalt is added to the plating bath as a coating modifier. A bright nickel plating can also be used as the base for the gold plating.

[0069] The film has a hardness of HV 70–200 and a maximum film thickness of 3.0 μm for the bright nickel layer and 0.1 μm for the gold layer.

[0070] (5) Silver layer

[0071] In this example, the silver layer can be a silver plating layer. For example, the silver plating layer is formed by an electroless plating method. The plating solution mainly consists of potassium silver cyanide (KAg(CN)2), and also includes free potassium cyanide (KCN) or sodium cyanide (NaCN), potassium carbonate (K2CO3), potassium hydroxide (KOH), brightener, and curing agent.

[0072] The film-forming process includes, in sequence, alkaline degreasing, water washing, chemical grinding, water washing, acid washing, water washing, neutralization, water washing, copper pre-plating, water washing, silver pre-plating, water washing (sometimes omitted), silver plating, water washing, anti-discoloration (sometimes omitted), and hot air drying.

[0073] The film has a hardness of HV 70–200 and a maximum film thickness of 3.0 μm for the glossy Ni layer and 2.0 μm for the silver layer.

[0074] It should be noted that the hardness (Vickers hardness) of the metal layer in this example was measured under the test conditions specified in JIS Z 2244 after the various metal layers were formed on the conductor 60 of the copper plate (after the Cu-Sn alloy layer was heat-treated).

[0075] The following are examples of preferred combinations of the first metal layer 71 (lower surface metal layer 73) and the second metal layer 72.

[0076] Glossy nickel layer and matte nickel layer

[0077] • Glossy nickel and gold layers

[0078] • Glossy nickel and silver layers

[0079] • Glossy nickel and tin layers (HV value of tin layer = approximately 10)

[0080] Nut 40 is provided on one side of the lower surface of external connection terminal 25. Nut 40 has nut hole 42. Nut 40 is pre-received in receiving portion 51 with opening provided in housing 50. Nut 40 can be formed of metal selected from alloys of iron, copper, aluminum, etc., or it can be formed of reinforced plastic.

[0081] Furthermore, the nut 40 has an end 44 on its upper surface on the side of the external connection terminal 25. The nut 40 contacts the lower surface metal layer 73 of the external connection terminal 25 at its end 44. Preferably, no other metal layer is provided between the nut 40 and the lower surface metal layer 73, and the nut 40 is in direct contact with the lower surface metal layer 73.

[0082] The outer diameter Dn of the nut 40 is the same as or smaller than the maximum diameter Ds of the screw 32. For example, the outer diameter Dn of the nut 40 is the outer diameter of the upper surface that contacts the external connection terminal 25 when externally connected. For example, the outer diameter Dn of the nut 40 is the same as or smaller than the outer diameter of the screw head 34. In other words, when externally connected, the nut 40 is completely covered by the screw 32 in a top view.

[0083] Figure 1D This is a cross-sectional view of the external connection portion 20 according to an embodiment of the present invention. Figure 1D yes Figure 1B An example of an A-A' cross-section (XZ) planar cross-section.

[0084] In the case of external connection, the external connection terminal 25 is disposed on the upper surface side of the nut 40, and then the busbar 30 is disposed on the upper surface side of the external connection terminal 25. Here, in top view, the external connection terminal 25 and the busbar 30 are configured such that the hole of the busbar 30, the threaded hole 28 of the external connection terminal 25, and the nut hole 42 of the nut 40 form concentric circles.

[0085] It should be noted that in this example, the nut 40 is sealed with resin 55 and fixed to the receiving portion 51 of the housing 50. As for the material of the resin 55, any material that can cure at room temperature and can fix the position of the nut 40 is acceptable. Alternatively, the resin 55 may not be provided, and the nut 40 may be fitted or embedded in the receiving portion 51 in a manner that prevents the nut 40 from rotating.

[0086] Furthermore, the nut 40 can be integrated with the housing 50. For example, the nut 40 is integrally formed (inserted) with the housing 50. The depth of the fixing position of the nut 40 is determined based on the overall design of the semiconductor module 100, such as the length of the screw 32.

[0087] The bolt portion 36 of the screw 32 passes through the threaded hole 28 of the busbar 30 and the external connection terminal 25 and is screwed into the nut hole 42 of the nut 40, so that the screw 32 is tightened together with the busbar 30 and the external connection portion 20.

[0088] After configuring the external connection terminal 25 and the busbar 30, screw in the screw 32 to tighten both the busbar 30 and the external connection portion 20. When the screw 32 is screwed in, the busbar 30 comes into contact with the second metal layer 72. In this example, the second metal layer 72 is formed of a low-hardness material such as matte nickel. Therefore, the contact resistance of the surface of the external connection terminal 25 that contacts the busbar 30 is low, and no gap is generated between the external connection terminal 25 and the busbar 30 when the screw 32 is screwed in. As a result, during external connection, the busbar 30 and the external connection terminal 25 can be fully fitted together.

[0089] Furthermore, if screw 32 is screwed in, a tightening torque will be generated on nut 40. Here, if the lower metal layer is relatively soft, the end 44 of nut 40 will slide on the lower metal layer and cannot be adequately supported by the external connection terminal 25, resulting in a greater burden of tightening torque caused by nut 40. As a result, the tightening torque on resin 55 used to support nut 40 also increases, which may cause cracking.

[0090] In this example, the lower surface metal layer 73 is formed of a high-hardness material such as nickel. Therefore, when the screw 32 is screwed in, the end 44 of the nut 40 is embedded in the lower surface metal layer 73, and the tightening torque can be borne by the nut 40 and the external connecting terminal 25, thus preventing the nut 40 from rotating.

[0091] Furthermore, as described above, the external connection terminal 25 in this example can be formed as a protruding shape protruding towards the upper surface of the external connection terminal 25. With this protruding external connection terminal 25, the end 44 of the nut 40 can easily contact the lower surface metal layer 73. In addition, the outer diameter Dn of the nut 40 is the same as or smaller than the maximum diameter Ds of the screw 32. Therefore, when the screw 32 is screwed in, the entire upper surface of the nut 40 is pressed by the screw head 34, reliably allowing the end of the nut 40 to embed into the lower surface metal layer 73.

[0092] Figure 2 This is a detailed planar view of the external connection portion 320 in the reference example. It should be noted that... Figure 2 In the middle, to and Figures 1A to 1D The same or similar symbols are used for the same constituent elements of the external connection part 20 described herein.

[0093] exist Figure 2 In this configuration, the external connection terminal 325 has a recessed shape on its upper surface side in the XY plane. Therefore, during external connection, the busbar 30 contacts the extension of the second metal layer 72 protruding towards the upper surface side, and the nut 40 contacts the lower surface metal layer 73 in the area surrounding the threaded hole 28. Consequently, the end 44 of the nut 40 may not make sufficient contact with the external connection terminal 325, or may be at a certain distance from it.

[0094] As described above, the lower surface metal layer 73 is formed of a material with high hardness. Therefore, if the contact between the end 44 of the nut 40 and the lower surface metal layer 73 is insufficient, the end 44 of the nut 40 will have difficulty fully embedding into the lower surface metal layer 73 when the screw 32 is tightened. As a result, the resin 55 used to support the nut 40 may crack under the tightening torque.

[0095] As described above, the external connection portion 320 of the reference example cannot make the busbar 30 and the external connection terminal 25 fit together as well as the external connection portion 20 of the embodiment of the present invention, and thus cannot make sufficient external connection.

[0096] Figure 3 This is a top surface view showing another example of the external connection portion 20 according to an embodiment of the present invention. Specifically, Figure 3 This is a view of the upper surface of the external connection part 25. It should be noted that... Figure 3 In the middle, to and Figures 1A to 1D The same or similar symbols are used for the same constituent elements as those described in the external connection part 20.

[0097] exist Figure 3 In this configuration, the first metal layer 71 is configured to cover the entire upper surface 62 of the conductor 60, but the second metal layer 72 is configured to cover a portion of the first metal layer 71. In this example, the second metal layer 72 covers the peripheral area of ​​the threaded hole 28 of the first metal layer 71 in a manner that forms a concentric circle with the threaded hole 28.

[0098] The area where the second metal layer 72 is set is determined based on the rigidity of the material used for the second metal layer 27, so that the busbar 30 and the external connection part 25 are sufficiently close during external connection. As an example, during external connection, the second metal layer 72 can be set in the area corresponding to the area occupied by the screw head 34 in a top view.

[0099] By having the second metal layer 72 cover only a portion of the first metal layer 71, costs can be suppressed compared to covering the entire first metal layer 71.

[0100] Figure 4 This is a cutaway view showing another example of the external connection portion 20 according to an embodiment of the present invention. It should be noted that... Figure 4 In the middle, to and Figures 1A to 1D The same or similar symbols are used for the same constituent elements of the external connection part 20 described herein.

[0101] like Figure 4 As shown, the nut 40 in this example is a flange nut with a flange on the side of the external connection terminal 25. In this case, the outer diameter Dn of the nut 40 is equivalent to the outer diameter of the flange, which is the same as or smaller than the outer diameter of the screw head 34. By using a flange nut as the nut 40, it is easy to apply torque to the nut 40 when screwing in the screw 32. This reliably prevents rotation of the nut 40.

[0102] Figure 5 This is an explanatory diagram illustrating a method for manufacturing the external connection portion 20 according to an embodiment of the present invention. The manufacturing method in this example includes steps S102 to S110.

[0103] In S102, a conductor 60 having an upper surface 62 and a lower surface 64 is provided. As an example, the conductor 60 is formed of copper.

[0104] In step S104, a first metal layer 71 is provided on the upper surface 62 of the conductor 60. Furthermore, a lower surface metal layer 73 is provided on the lower surface 64 of the conductor 60. For example, the first metal layer 71 and the lower surface metal layer 73 are simultaneously provided by immersing the conductor 60 in an electroplating solution. Both the first metal layer 71 and the lower surface metal layer 73 can be nickel plating.

[0105] In step S106, a second metal layer 72 is formed on the first metal layer 71. For example, a mask is formed on the lower surface 64 of the conductor 60, and the conductor 60 is immersed in an electroplating solution, thereby forming the second metal layer 72 on the first metal layer 71. The second metal layer 72 can be any one of a gold plating layer, a matte nickel plating layer, a copper-tin alloy plating layer, or a silver plating layer.

[0106] External connection terminals 25 are provided via S102 to S106.

[0107] In S108, the external connection terminal 25 is machined into a protruding shape that faces upwards. In this example, the external connection terminal 25 is positioned on the mold and along... Figure 5 The direction indicated by the black arrow is to press the outer portion in the XY plane from top to bottom, and press the center portion from bottom to top, thereby processing it into a convex shape. In addition, in S108, punching and blanking are performed simultaneously on the external connection terminal 25 to form a threaded hole 28.

[0108] In S110, a nut 40 is provided on the lower surface side of the external connection terminal 25. For example, the external connection terminal 25 is arranged on the nut 40 pre-accommodated in the receiving portion 51 of the housing 50 in such a way that the threaded hole 28 and the nut hole 42 form a concentric circle.

[0109] Figure 6 This is a schematic diagram of a vehicle 200 according to an embodiment of the present invention. The vehicle 200 is a vehicle that generates at least a portion of its propulsion using electricity. As an example, the vehicle 200 is an electric vehicle that generates all its propulsion using an electric drive device such as a motor, or a hybrid vehicle that uses both an electric drive device such as a motor and an internal combustion engine that is driven by fuel such as gasoline.

[0110] The vehicle 200 has a control device 210 (external device) for controlling electrically driven equipment such as motors. The control device 210 includes a semiconductor module 100. The semiconductor module 100 can control the power supplied to the electrically driven equipment.

[0111] Figure 7This is a main circuit diagram of the semiconductor module 100 according to an embodiment of the present invention. The semiconductor module 100 may be part of an on-board unit for driving a motor in a vehicle. The semiconductor module 100 may function as a three-phase AC converter circuit having input terminals P and N, and output terminals U, V, and W.

[0112] Semiconductor chips 80 are connected in parallel with the first semiconductor chip 78 and the second semiconductor chip 79. Semiconductor chips 80-1, 80-2, and 80-3 can form the lower arm of semiconductor module 100. Semiconductor chips 80-4, 80-5, and 80-6 can form the upper arm of semiconductor module 100. A group of semiconductor chips 80-1 and 80-4 can form a branch. A group of semiconductor chips 80-2 and 80-5 can form a branch. A group of semiconductor chips 80-3 and 80-6 can form a branch.

[0113] In semiconductor chip 80-1, the emitter electrodes of the first semiconductor chip 78-2 and the second semiconductor chip 79-2 can be electrically connected to the input terminal N1, and the collector electrodes of the first semiconductor chip 78-2 and the second semiconductor chip 79-2 can be electrically connected to the output terminal U. In semiconductor chip 80-4, the emitter electrodes of the first semiconductor chip 78-1 and the second semiconductor chip 79-1 can be electrically connected to the output terminal U, and the collector electrodes of the first semiconductor chip 78-1 and the second semiconductor chip 79-1 can be electrically connected to the input terminal P1.

[0114] In semiconductor chip 80-2, the emitter electrodes of the first semiconductor chip 78-2 and the second semiconductor chip 79-2 can be electrically connected to the input terminal N2, and the collector electrodes of the first semiconductor chip 78-2 and the second semiconductor chip 79-2 can be electrically connected to the output terminal V. In semiconductor chip 80-5, the emitter electrodes of the first semiconductor chip 78-1 and the second semiconductor chip 79-1 can be electrically connected to the output terminal V, and the collector electrodes of the first semiconductor chip 78-1 and the second semiconductor chip 79-1 can be electrically connected to the input terminal P2.

[0115] In semiconductor chip 80-3, the emitter electrodes of the first semiconductor chip 78-2 and the second semiconductor chip 79-2 can be electrically connected to the input terminal N3, and the collector electrodes of the first semiconductor chip 78-2 and the second semiconductor chip 79-2 can be electrically connected to the output terminal W. In semiconductor chip 80-6, the emitter electrodes of the first semiconductor chip 78-1 and the second semiconductor chip 79-1 can be electrically connected to the output terminal W, and the collector electrodes of the first semiconductor chip 78-1 and the second semiconductor chip 79-1 can be electrically connected to the input terminal P3.

[0116] Semiconductor chips 80-1 to 80-6 can be alternately turned on and off according to signals input to the control electrode pads of the first semiconductor chip 78 and the second semiconductor chip 79. In this example, the first semiconductor chip 78 and the second semiconductor chip 79 can generate heat during switching.

[0117] Input terminals P1, P2, and P3 can be connected to the positive terminal of an external power supply via bus 30. Input terminals N1, N2, and N3 can be connected to the negative terminal of an external power supply via bus 30. Input terminals P1, P2, and P3 can be electrically connected to each other. Input terminals N1, N2, and N3 can be electrically connected to each other. Output terminals U, V, and W can be connected to the load via bus 30 respectively.

[0118] In semiconductor module 100, the first semiconductor chip 78 and the second semiconductor chip 79 can each be an RC-IGBT (reverse-conduction IGBT) semiconductor chip. In the RC-IGBT semiconductor chip, the IGBT and FWD can be connected in reverse parallel. The first semiconductor chip 78 and the second semiconductor chip 79 can each contain a combination of transistors and diodes such as MOSFETs and / or IGBTs.

[0119] As described above, embodiments of the present invention have been illustrated, but the technical scope of the present invention is not limited to the scope of the embodiments described above. Those skilled in the art should understand that various modifications or improvements can be made to the above embodiments. As can be seen from the claims, adding such modifications or improvements also falls within the technical scope of the present invention.

[0120] It should be noted that the execution order of various processes, such as actions, sequences, steps, and stages, in the apparatus, system, program, and method shown in the claims, specification, and drawings can be implemented in any order, unless specifically stated as "before," "beforehand," etc., and unless the results of previous processes are used in later processes. Even if terms such as "firstly" or "then" are used for convenience in the action flow of the claims, specification, and drawings, it does not mean that the actions must be performed in that order.

Claims

1. An external connecting part, characterized in that, It is an external connection part of the semiconductor module, the external connection part having an external connection terminal and a nut disposed on the lower surface side of the external connection terminal. The external connection terminal has: conductor; A first metal layer is disposed on the upper surface of the conductor; A second metal layer disposed on the first metal layer; as well as A lower surface metal layer disposed on the lower surface of the conductor. The first metal layer has a higher hardness than the second metal layer. The first metal layer is formed of the same material as the lower surface metal layer. The nut is in direct contact with the lower surface metal layer. The outermost surfaces of the external connection terminals that connect with other components are composed of a second metal layer and a lower surface metal layer with different hardness.

2. The external connecting part according to claim 1, characterized in that, The conductor has a thickness of 1.0 mm or more and 7.0 mm or less, the first metal layer has a thickness of 0.1 μm or more and 10 μm or less, the second metal layer has a thickness of 0.1 μm or more and 10 μm or less, and the lower surface metal layer has a thickness that is the same as or greater than that of the first metal layer.

3. The external connecting part according to claim 1 or 2, characterized in that, The conductor is formed of copper or a copper alloy, the first metal layer and the lower surface metal layer are glossy nickel layers, and the second metal layer is a gold layer, a matte nickel layer, a copper-tin alloy layer or a silver layer.

4. The external connecting part according to claim 1 or 2, characterized in that, The second metal layer is configured to cover a portion of the first metal layer.

5. The external connecting part according to claim 1 or 2, characterized in that, The outer diameter of the nut is the same as or smaller than the maximum diameter of the screw corresponding to the nut.

6. The external connecting part according to claim 1 or 2, characterized in that, The nut is integrally formed with the housing of the semiconductor module.

7. The external connecting part according to claim 1 or 2, characterized in that, The nut is a flange nut having a flange on one side of the external connection terminal.

8. A manufacturing method, characterized in that, The manufacturing method is a method for manufacturing an external connection portion of a semiconductor module. The manufacturing method includes the steps of providing an external connection terminal and setting a nut on one side of the lower surface of the external connection terminal. The step of providing the external connection terminal includes: Steps for setting up a conductor; The step of forming a first metal layer on the upper surface of the conductor; The step of depositing a second metal layer on the first metal layer; as well as The step of forming a lower surface metal layer on the lower surface of the conductor. The first metal layer has a higher hardness than the second metal layer. The first metal layer is formed of the same material as the lower surface metal layer. The nut is in direct contact with the lower surface metal layer. The outermost surfaces of the external connection terminals that connect with other components are composed of a second metal layer and a lower surface metal layer with different hardness.

9. The manufacturing method according to claim 8, characterized in that, The step of providing the external connection terminal includes forming the external connection terminal having a protruding shape that protrudes towards the upper surface.

10. A semiconductor module, characterized in that, It has an external connecting part as described in any one of claims 1 to 7.

11. A vehicle, characterized in that, It has the semiconductor module as described in claim 10.

12. A connection method, characterized in that, The connection method is the connection method between the external connection part and the busbar as described in claim 1, and the connection method includes: The step of configuring the busbar on one side of the upper surface of the external connection terminal; The step of inserting the bolt portion of a screw into the hole of the busbar and the threaded hole of the external connection terminal; and The step of screwing in the screw to embed the end of the nut into the lower surface metal layer.

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