Semiconductor module

Abstract

The invention relates to a semiconductor module. The purpose of the present invention is to suppress an increase in manufacturing cost of a semiconductor module due to an increase in a creepage distance associated with insulating properties. A semiconductor module (1) is provided with: a semiconductor element (3); a sealing member (7) having a main body portion (700) that seals the semiconductor element; and a plurality of leads (4) each having an inner lead portion extending inside the main body portion of the sealing member and an outer lead portion extending outside the main body portion and bent at a predetermined bending position, the sealing member having a covering portion (750), and a covering portion that individually covers the entire surface of a section from a boundary with the internal lead portion to a position closer to the boundary than the bent position in the external lead portion of the lead in a manner for each section of the external lead portion.

Description

Technical Field

[0001] The present invention relates to a semiconductor module. Background Art

[0002] In a DIP (Dual Inline Package) type semiconductor module, in order to extend the creepage distance related to insulation performance, the outer lead portion of the lead is sometimes coated with a coating material different from the sealing member that seals the semiconductor element (for example, refer to Patent Document 1). Further, in order to extend the creepage distance between leads, a protruding portion protruding between the leads is sometimes formed in the sealing member (for example, refer to Patent Documents 2 and 3).

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2020-53611

[0006] Patent Document 2: Japanese Unexamined Patent Application Publication No. 2013-84838

[0007] Patent Document 3: Japanese Unexamined Patent Application Publication No. 6-61375 Summary of the Invention

[0008] Problems to be Solved by the Invention

[0009] When extending the creepage distance by the above-described method, the manufacturing cost increases due to an increase in the number of manufacturing processes, an increase in the amount of material used, and the like.

[0010] In one aspect, an object of the present invention is to suppress an increase in the manufacturing cost of a semiconductor module due to extending the creepage distance related to insulation performance.

[0011] Solution to the Problem

[0012] A semiconductor module according to one aspect includes: a semiconductor element; a sealing member having a main body portion that seals the semiconductor element; and a plurality of leads each having an internal lead portion extending in the main body portion of the sealing member and an external lead portion extending outside the main body portion and bent at a predetermined bending position, the sealing member having a covering portion that individually covers the entire surface of an interval of the external lead portion of the lead from a boundary with the internal lead portion to a position closer to the boundary than the bending position for each interval of each external lead portion.

[0013] Effects of the Invention

[0014] According to the above technical solution, it is possible to suppress an increase in the manufacturing cost of the semiconductor module due to an increase in the creepage distance related to the insulation performance. Description of the Drawings

[0015] Figure 1 is a bottom view of the semiconductor module of the embodiment.

[0016] Figure 2 is an illustration Figure 1 A cross-sectional view of a first structural example in the sealing member of the semiconductor module of.

[0017] Figure 3 is an illustration Figure 1 A cross-sectional view of a second structural example in the sealing member of the semiconductor module of.

[0018] Figure 4 is an illustration Figure 1 A circuit diagram of a circuit structural example of the semiconductor module of.

[0019] Figure 5 is an enlarged Figure 1 A perspective view of the periphery of the covering portion in the semiconductor module of.

[0020] Figure 6 is a view (part 1) for explaining the manufacturing method of the semiconductor module of the embodiment.

[0021] Figure 7 is a view (part 2) for explaining the manufacturing method of the semiconductor module of the embodiment.

[0022] Figure 8 is a view for explaining the relationship between the lead frame and the cavity of the mold.

[0023] Figure 9 is Figure 8 A cross-sectional view taken along the dotted line B - B' of.

[0024] Figure 10 is a bottom view for explaining an example of the process of singulating the leads.

[0025] Figure 11 is a front view for explaining an example of the process of bending the external lead portion.

[0026] Figure 12 is a bottom view for explaining a modified example of the shape of the covering portion.

[0027] Figure 13 is Figure 12 A cross-sectional view taken along the dotted line C - C' of.

[0028] Description of Reference Numerals

[0029] 1. Semiconductor module; 2. Chip pad; 3A, 3B. Semiconductor element; 4, 4A - 4Q. Lead; 401, 402. Side surface; 403. Lower surface; 5, 5A, 5B. Bonding wire; 6. Heat dissipation member; 6A. Metal layer; 6B. Insulating layer; 7. Sealing member; 700. Main body part; 701, 702. End face; 703. Lower surface; 710. Housing member; 720. Filling member; 750. Covering part; 8. Cooler; 9A. Bonding material; 9B. Heat conducting member; 10A, 10B. IGBT element; 11A, 11B. Diode element; 13A, 13B. Control circuit; 15. Upper mold; 16. Lower mold; 1500, 1600. Recess; 17. Mold cavity; 18 - 20. Mold; YLB. Bending position. Detailed implementation mode

[0030] The implementation mode of the present invention will be described in detail below with reference to the drawings. The "semiconductor module" in the following description is formed by sealing semiconductor elements (semiconductor chips) with an insulating material, and is sometimes also referred to as a "semiconductor device", "semiconductor package", etc.

[0031] The X-axis, Y-axis, and Z-axis in each figure for reference are shown for the purpose of defining planes and directions in the illustrated semiconductor module. The X-axis, Y-axis, and Z-axis are orthogonal to each other and form a right-handed system. In the following description, the direction parallel to the X-axis is referred to as the X direction, the direction parallel to the Y-axis is referred to as the Y direction, and the direction parallel to the Z-axis is referred to as the Z direction. In addition, for each direction of the X direction, Y direction, and Z direction, when it is associated with the arrow (positive or negative) direction of the illustrated X-axis, Y-axis, and Z-axis, "positive side" or "negative side" is added.

[0032] In this specification, the Z direction is sometimes referred to as the up-down direction. In this specification, "up" and "above" mean closer to the positive side of the Z direction than a reference plane, member, position, etc., and "down" and "below" mean closer to the negative side of the Z direction than a reference plane, member, position, etc. For example, when it is described that "member B is disposed above member A", member B is disposed on the positive side of the Z direction as viewed from member A. In addition, when it is described as "the upper surface of member A", this surface includes the end portion of member A located on the positive side of the Z direction and the surface facing the positive side of the Z direction. These directions and the surfaces related to the directions are terms used for convenience of explanation, and the corresponding relationships with the directions of the X-axis, Y-axis, and Z-axis may change depending on the installation posture of the semiconductor module, etc. For example, in this specification, the surface of the semiconductor element opposite to the chip pad is referred to as the lower surface, and the surface on the opposite side of the lower surface is referred to as the upper surface, but it is not limited thereto, and the surface of the semiconductor element opposite to the chip pad may also be referred to as the upper surface, and the surface on the opposite side thereof may be referred to as the lower surface.

[0033] The aspect ratios in the respective figures and the size relationships between the respective components are merely shown schematically and are not necessarily the same as those in an actually manufactured semiconductor module. For the sake of convenience in explanation, there is also a case where the size relationships between the respective components are exaggeratedly shown. In addition, for the sake of convenience in explanation, several of the cross-sectional views show the cross-sectional structure of the semiconductor module cut by a hypothetical cutting line that cannot be accurately shown in the top view.

[0034] The notations such as "not shown in the drawing", "not illustrated", and "not drawn" in this specification mean that the structural element with this notation is not clearly shown in the drawing by using a designated reference numeral and a leader line. For example, the "first main electrode not shown in the drawing" means that the part representing the first main electrode (e.g., a figure, a line, etc.) is not shown in the drawing and there are no reference numerals and leader lines in the drawing that clearly represent the part corresponding to the first main electrode. In addition, the underlined reference numerals in the drawing represent the entire structural element including a plurality of parts distinguished by using a plurality of reference numerals.

[0035] The semiconductor module exemplified in the following description can be applied to, for example, a power conversion device such as an inverter device for industrial use or electrical equipment use (e.g., an in-vehicle motor). Therefore, in the following description, detailed descriptions of structures, functions, operations, manufacturing methods, etc. that are the same as or similar to those of a known semiconductor module are omitted.

[0036] Figure 1 is a bottom view of the semiconductor module of the embodiment. Figure 2 is an illustration Figure 1 of a cross-sectional view of a first structural example in the sealing member of the semiconductor module. Figure 3 is an illustration Figure 1 of a cross-sectional view of a second structural example in the sealing member of the semiconductor module. Figure 2 and Figure 3 The cross-sectional views show a cross-sectional structural example of the semiconductor module 1 obtained by cutting with a hypothetical cutting line connecting the dash-dotted line A and another dash-dotted line A'. The dash-dotted line A passes through Figure 1 one lead of the semiconductor module 1 on the negative side in the Y direction, and the dash-dotted line A' passes through another lead on the positive side in the Y direction.

[0037] Figures 1 to 3 The semiconductor module 1 exemplified in includes a chip pad 2, semiconductor elements 3A, 3B, leads 4 (4A to 4X), bonding wires 5 (5A, 5B), a heat dissipation member 6, and a sealing member 7. The semiconductor module 1 may also include a cooler 8 (see Figure 2 ), but in this specification, except for Figure 2 and Figure 3A semiconductor package of the DIP (Dual Inline Package) type other than the cooler 8 illustrated in the figure is referred to as a semiconductor module 1. In addition, in this specification, when specifying a specific lead among a plurality of leads 4A to 4X, the reference numeral (any one of 4A to 4X) assigned to the specific lead in Figure 1 is described. In other cases, it is only described as "lead 4". Similarly, when specifying a specific bonding wire among a plurality of bonding wires 5A and 5B, the reference numeral (any one of 5A and 5B) assigned to the specific bonding wire in Figure 2 etc. is described. In other cases, it is only described as "bonding wire 5".

[0038] The chip pad 2 is a component on which the semiconductor element 3A is mounted. The semiconductor element 3A is sometimes also referred to as a semiconductor chip or a chip. The semiconductor element 3A can be, for example, an RC (Reverse Conducting) - IGBT element that integrates the functions of an IGBT (Insulated Gate Bipolar Transistor) element as a switching element and a diode element such as an FWD (Free Wheeling Diode) element reversely connected in parallel with the IGBT element. In addition, the semiconductor element 3A can be, for example, a MOSFET (Metal Oxide Semiconductor Field Effect Transistor) element as a switching element. Such a semiconductor element 3A has a first main electrode (not shown) on the lower surface, and a second main electrode and a control electrode (gate electrode) (not shown) on the upper surface. When the switching element in the semiconductor element 3A is an IGBT element, the first main electrode on the lower surface side can be referred to as the collector, and the second main electrode on the upper surface side can be referred to as the emitter. The semiconductor substrate forming the switching element and the diode element in the semiconductor element 3A is not limited to a silicon substrate, and can also be a substrate using a wide bandgap semiconductor such as a SiC (silicon carbide) substrate or a GaN (gallium nitride) substrate.

[0039] The semiconductor element 3A is joined to the upper surface of the chip pad 2 using a joining material 9A such as solder, etc., and the first main electrode is electrically connected to the chip pad 2. The chip pad 2 is electrically connected to a lead 4 (any one of 4Q to 4X) extending in the positive Y direction from the hermetic member 7 using a bonding wire 5A. Further, the second main electrode of the semiconductor element 3A is electrically connected to another lead 4 (any one of the leads among 4Q to 4X that is not connected to the bonding wire 5A) extending in the positive Y direction from the hermetic member 7 using a bonding wire (not shown). The control electrode of the semiconductor element 3A is electrically connected to a semiconductor element 3B serving as a control IC using a bonding wire 5B, for example. The semiconductor element 3B is joined to the upper surface of a portion (internal lead portion) of the lead 4 buried in the hermetic member 7 using a joining material. The number and type of semiconductor elements joined to the upper surface of the chip pad 2 and the upper surface of the internal lead portion are not limited to specific numbers and types. For example, it may be that a semiconductor element functioning as an IGBT element and a semiconductor element functioning as a diode element as described above are joined to the upper surface of the chip pad 2 in a reverse parallel connection manner.

[0040] A heat dissipation member 6 is connected to the lower surface of the chip pad 2. The heat dissipation member 6 includes a metal layer 6A exposed from the lower surface 703 of the hermetic member 7 and an insulating layer 6B disposed on the upper surface of the metal layer 6A. The metal layer 6A is formed of, for example, a metal plate or metal foil of copper, aluminum, etc. The insulating layer 6B may be, for example, a ceramic substrate formed of a ceramic material such as alumina (Al2O3), aluminum nitride (AlN), silicon nitride (Si3N4), or a composite material of alumina (Al2O3) and zirconia (ZrO2). The insulating layer 6B may also be, for example, a substrate formed by molding an insulating resin such as epoxy resin, a substrate obtained by impregnating a base material such as glass fiber with an insulating resin, or a substrate obtained by coating the surface of a flat metal core with an insulating resin. The heat dissipation member 6 may also be a DCB (Direct Copper Bonding) substrate or an AMB (Active Metal Brazing) substrate having a metal layer formed on the upper surface of the insulating layer 6B. The metal layer formed on the upper surface of the insulating layer 6B may be the chip pad 2 or a metal plate or metal foil different from the chip pad 2. The combination of the chip pad 2 and the heat dissipation member 6 is an example of an element mounting member for mounting a semiconductor element.

[0041] The chip pad 2, semiconductor elements 3A and 3B, bonding wires 5, and the connection portion of the lead 4 connected to the bonding wire 5 and its peripheral portion (hereinafter referred to as "internal lead portion") are sealed by a sealing member 7. The sealing member 7 in the semiconductor module 1 of the present embodiment has a main body portion 700 and a covering portion 750. The main body portion 700 is a substantially square-shaped portion that seals the chip pad 2, semiconductor elements 3A and 3B, bonding wires 5, and the internal lead portion of the lead 4 in such a manner that the lower surface (metal layer 6A) of the heat dissipation member 6 is exposed. The covering portion 750 is a substantially cylindrical portion that covers, for each external lead portion, the portion of the lead 4 extending outward from the main body portion 700 (hereinafter referred to as "external lead portion").

[0042] As described above, the semiconductor module 1 of the present embodiment is a DIP-type semiconductor package, and the leads 4 extend outward from the end faces 701 and 702 of the main body portion 700 of the sealing member 7 located in a direction (Y direction) parallel to the in-plane direction of the lower surface 703. The leads 4A to 4P (for control signals) extend from the end face 701 on the negative side in the Y direction of the main body portion 700 in the negative Y direction, and the leads 4Q to 4X (for main current) extend from the end face 702 on the positive side in the Y direction of the main body portion 700 in the positive Y direction. For example, as Figure 2 and Figure 3 shown, the leads 4 of the semiconductor module 1 are bent at the bending positions located in the external lead portions. The section of the external lead portion from the bending position to the end on the side opposite to the boundary with the internal lead portion is bent in the direction (positive Z direction) toward the upper surface of the main body portion 700. In other words, when a cooler 8 is connected to the lower surface of the semiconductor module 1, the external lead portions of the leads 4 are bent away from the cooler 8. The cooler 8 is thermally connected to the metal layer 6A of the heat dissipation member 6 exposed from the lower surface 703 of the sealing member 7 by means of a heat conduction member 9B such as thermal grease or thermal compound. The cooler 8 can circulate a refrigerant such as cooling water, for example, to dissipate the heat generated by the semiconductor element 3A. The cooler 8 can also be a member such as a radiator that dissipates the heat generated by the semiconductor element 3A to the air, for example.

[0043] For example, as Figure 2As shown, the main body portion 700 of the sealing member 7 includes a housing member 710 having a space for accommodating semiconductor elements 3A, 3B, etc., and an insulating filling member 720 filled in the space of the housing member 710. In this case, the lead 4 is integrated with the housing member 710 such that a part of the internal lead portion is exposed in the space of the housing member 710 for accommodating the semiconductor elements 3A, 3B, etc., and is supported by the housing member 710. In the semiconductor module 1 having the housing member 710, a set of a chip pad 2 as an element mounting member and a heat dissipation member 6 is joined to the housing member 710 by the filling member 720 such that the surface on the side opposite to the surface (the upper surface of the chip pad 2) on which the semiconductor element 3A is mounted (the lower surface of the heat dissipation member 6) is exposed from the main body portion 700. In Figure 2 the illustrated semiconductor module 1, covering portions 750 are integrally formed individually for each lead 4 on the end face 701 on the negative Y-direction side and the end face 702 on the positive Y-direction side in the housing member 710.

[0044] In addition, for the main body portion 700 of the sealing member 7, for example, as Figure 3 shown, the entire main body portion 700 may be formed of the same insulating resin, and covering portions 750 are integrally formed individually for each lead 4 on the end face 701 on the negative Y-direction side and the end face 702 on the positive Y-direction side in the main body portion 700.

[0045] As described above with reference to Figures 1 to 3 the semiconductor module 1 can be a module including a three-phase inverter circuit and a control circuit, which is sometimes referred to as an IPM (Intelligent Power Module).

[0046] Figure 4 is a circuit diagram for explaining Figure 1 an example of the circuit structure of the semiconductor module. Figure 4 Only a part of the three-phase inverter circuit and the control circuit included in the semiconductor module 1 is illustrated in

[0047] A power conversion circuit for converting direct current into three-phase alternating current of U-phase, V-phase, and W-phase and outputting it is formed in the semiconductor module 1. Figure 4A half-bridge inverter circuit that outputs direct current as alternating current of the U phase is illustrated. The illustrated half-bridge inverter circuit includes two IGBT elements 10A and 10B connected in series between a first lead 4W and a second lead 4S, and diode elements (FWD elements) 11A and 11B connected in anti-parallel with the two IGBT elements 10A and 10B respectively. The first lead 4W is a P terminal connected to the positive electrode of a direct current power supply, and the second lead 4S is an N(U) terminal connected to the negative electrode of the direct current power supply. The collector of the IGBT element 10A of the upper arm 12A among the two IGBT elements is connected to the first lead 4W, and the emitter electrode of the IGBT element 10B of the lower arm 12B is connected to the second lead 4S. The emitter electrode of the IGBT element 10A of the upper arm 12A and the collector of the IGBT element 10B of the lower arm 12B are connected to a third lead 4V that is an output terminal of the U-phase alternating current. The gate of the IGBT element 10A of the upper arm 12A is connected to a first control circuit 13A, and the gate of the IGBT element 10B of the lower arm 12B is connected to a second control circuit 13B. Leads 4A to 4H extending toward the negative side in the Y direction from an end face 701 in the main body portion 700 of the self-sealing member 7 are connected to the first control circuit 13A, and leads 4I to 4P extending toward the negative side in the Y direction from the end face 701 are connected to the second control circuit 13B.

[0048] The half-bridge inverter circuit that outputs direct current as alternating current of the V phase and the half-bridge inverter circuit that outputs direct current as alternating current of the W phase can each be a circuit structure the same as that of the half-bridge inverter circuit that outputs direct current as alternating current of the U phase illustrated in Figure 4 above. The first control circuit 13A controls the voltage applied to the gate of the IGBT element 10A of the upper arm 12A of the U phase, V phase, and W phase based on the drive power supply voltage and the like input from the plurality of leads 4A to 4H. The second control circuit 13B controls the voltage applied to the gate of the IGBT element 10B of the lower arm 12B of the U phase, V phase, and W phase based on the drive power supply voltage and the like input from the plurality of leads 4I to 4P.

[0049] The above-mentioned Figure 4 The circuit structure of the semiconductor module 1 described with reference to is only an illustration of the power conversion circuit formed within the main body portion 700 of the sealing member 7. The circuit formed within the main body portion 700 can also be a power conversion circuit with other circuit structures. The circuit formed within the main body portion 700 can include a circuit different from the power conversion circuit, can form a part of the power conversion circuit, or can only form a circuit different from the power conversion circuit.

[0050] Figure 5 is an enlarged Figure 1 is a perspective view of the periphery of the covering portion in the semiconductor module. In the following, with reference to Figure 5In the description, only the structure on the end face 701 side of the main body portion 700 of the sealing member 7 is described, and the structure on the opposite end face 702 side may be the same.

[0051] As described above, for the semiconductor module 1 of the present embodiment, the external lead portions of the leads 4 extending from the main body portion 700 of the sealing member 7 are covered by the covering portions 750 for each lead 4. For example, as Figure 5 shown, the external lead portion of the lead 4 is bent at a bending position YLB that is a predetermined distance from the end face 701 of the main body portion 700 of the sealing member 7 (in other words, the boundary with the internal lead portion) in the extending direction (Y direction) of the lead 4. The covering portion 750 is integrally formed with the main body portion 700 and covers the entire surface of the interval of the length L1 from the end face 701 of the main body portion 700 to a predetermined position on the end face 701 side of the main body portion 700 closer than the bending position YLB in the external lead portion.

[0052] Figure 5 The thickness H1 of the illustrated covering portion 750 starting from the side surfaces 401, 402 of the external lead portion is the same thickness. The side surfaces 401, 402 are the surfaces of the external lead portion that are opposite to the surfaces of the adjacent external lead portions extending from the end face 701 of the main body portion 700. Therefore, if the gap between the adjacent covering portions 750 is G and the length of the covering portion 750 in the extending direction (Y direction) of the lead 4 is L1, the creepage distance Dcr1 between the adjacent leads 4 (external lead portions) extending from the end face 701 of the main body portion 700 becomes the sum of the gap G between the adjacent covering portions 750, the thickness H1 of the covering portion 750 starting from the side surfaces 401, 402 of the external lead portion, and the lengths L1 of the covering portions 750 that cover the adjacent leads 4 respectively. That is, the creepage distance Dcr1 between the adjacent leads 4 (external lead portions) extending from the end face 701 of the main body portion 700 becomes the length obtained by summing the length from the side surface 401 of the lead 4 (external lead portion) to the side surface 402 of the adjacent lead 4 (external lead portion) and the lengths L1 of the covering portions 750 that cover the adjacent leads 4 respectively. In addition, the respective thicknesses H1 of the illustrated covering portion 750 starting from the side surfaces 401, 402 of the external lead portion are not limited to the same thickness, and the thicknesses may also be different. Further, as long as the length L1 of the covering portion 750 can ensure the creepage distance, the lengths of the covering portions 750 that cover the adjacent leads 4 may also be different.

[0053] In addition, the thickness H2 of the covering portion 750 at the lower surface 403 and the upper surface (not shown) of the external lead portion can be 1 mm or less. In contrast, the thickness of the main body portion 700 in the vertical direction (Z direction) can be several millimeters to more than ten millimeters. If the distance from the end surface 701 of the main body portion 700 to the metal layer 6A of the heat dissipation member 6 on the lower surface 703 of the main body portion 700 is set as L2, and the distance from the lower surface 703 of the main body portion 700 to the covering portion 750 is set as H3, then the creepage distance Dcr2 between the lead 4 (external lead portion) and the metal layer 6A of the heat dissipation member 6 becomes the sum of the distance L2 from the end surface 701 to the metal layer 6A of the heat dissipation member 6, the distance H3 from the lower surface 703 to the covering portion 750, the length L1 of the covering portion 750 in the extending direction (Y direction) of the lead 4, and the thickness H1 of the covering portion 750 starting from the side surfaces 401 and 402 of the external lead portion.

[0054] That is, in the semiconductor module 1 of the present embodiment, the sealing member 7 has the covering portion 750 that covers the external lead portion of the lead 4. Thus, compared with the semiconductor module without the covering portion 750, the creepage distance between adjacent leads 4 (external lead portions) can be extended by a distance that is the sum of the lengths L1 of the respective covering portions 750 that individually cover the adjacent leads 4. In addition, compared with the semiconductor module without the covering portion 750, the semiconductor module 1 of the present embodiment can extend the creepage distance between the lead 4 (external lead portion) and the metal layer 6A of the heat dissipation member 6 by the length L1 of the covering portion 750. Furthermore, the covering portion 750 does not need to be provided on all the leads 4A to 4X, and it is sufficient to be provided only on the leads 4 where the creepage distance needs to be ensured. For example, the covering portion 750 is sufficient to be provided on the leads 4Q to 4X for the main current.

[0055] Figure 6 FIG. is a diagram (part 1) for explaining a manufacturing method of the semiconductor module of the embodiment. Figure 7 FIG. is a diagram (part 2) for explaining a manufacturing method of the semiconductor module of the embodiment. Figure 8 FIG. is a diagram showing the relationship between the lead frame and the cavity of the mold. Figure 9 is Figure 8 a cross-sectional view taken along the dotted line B - B' of Figure 6 and Figure 7 illustrates a mold for manufacturing the semiconductor module 1 in which the entire main body portion 700 exemplified in Figure 3 is made of the same sealing resin.

[0056] The manufacturing method of the semiconductor module 1 of the present embodiment may be the same as the manufacturing method of a well-known DIP-type semiconductor package. However, in the sealing process of sealing semiconductor elements 3A, 3B, etc. with an insulating material, the sealing member 7 having the main body portion 700 and the covering portion 750 described above is formed. Therefore, in the sealing process, for example, transfer molding using the molds (upper mold 15 and lower mold 16) shown in Figures 6 to 9 is performed. The illustrated upper mold 15 and lower mold 16 each have a concave portion 1500 and a concave portion 1600 (refer to Figure 6 and Figure 7 ), and the concave portion 1500 and the concave portion 1600 are formed to define a space (mold cavity) 17 corresponding to the outer shape of the sealing member 7 around semiconductor elements 3A, 3B, etc. to be sealed when the molds are closed. The upper mold 15 and the lower mold 16 are formed with gates (not shown) and the like for injecting an insulating material into the mold cavity 17 after the molds are closed.

[0057] The concave portion 1500 of the upper mold 15 and the concave portion 1600 of the lower mold 16 used in manufacturing the semiconductor module of the present embodiment each include a first concave portion 1501, 1601 for forming the main body portion 700 of the sealing member 7 and a second concave portion 1502, 1602 for forming the covering portion 750. For example, as shown in Figure 8 and Figure 9 , the second concave portions 1502, 1602 are formed individually for each lead 4 formed on the lead frame 400, and define an annular space for exposing the surface around the lead 4. Lead pressing portions 1503, 1603 are formed at positions of the upper mold 15 and the lower mold 16 that face the outer lead portions of the lead frame 400. The lead pressing portions 1503, 1603 clamp the lead frame 400 when the molds are closed and prevent the insulating material flowing into the second concave portions 1502, 1602 from leaking out.

[0058] At the time of performing the sealing process, the plurality of leads 4 are in the state of the lead frame 400 integrated by the frame portion 410, the connecting rod 411, etc., and the portions of the respective leads 4 that become the outer lead portions are not bent. The plurality of leads 4 in the lead frame 400 are connected to each other by the connecting rod 411, etc. at positions that do not overlap with the mold cavity 17 defined when the upper mold 15 and the lower mold 16 are closed.

[0059] The shapes of the concave portion 1500 of the upper mold 15 and the concave portion 1600 of the lower mold 16 only need to be shapes that define a space (mold cavity) 17 corresponding to the entire sealing member 7 including the main body portion 700 and the covering portion 750 when the lead frame 400 is clamped and the molds are closed, and are not limited to specific shapes. For example, the shapes of the concave portion 1500 of the upper mold 15 and the concave portion 1600 of the lower mold 16 may also be shapes that define, when the molds are closed, a space for forming the one described above with reference to Figure 2Describes the shape of the space of the housing member 710 and the covering portion 750 of the main body portion 700. In addition, the second recesses 1502 and 1602 for forming the covering portion 750 may be formed at positions corresponding to the lead 4 whose surface distance is desired to be extended. That is, the second recesses 1502 and 1602 for forming the covering portion 750 may be formed at positions corresponding to one or more leads among all the leads 4 (external lead portions).

[0060] Figure 10 Is a bottom view showing an example of the process of separating the leads into individual pieces. Figure 11 Is a front view showing an example of the process of bending the external lead portion. Figure 10 、 Figure 11 Only the structure on the end face 701 side of the main body portion 700 of the sealing member 7 is illustrated, but the structure on the opposite end face 702 side may be the same.

[0061] After the sealing process, in order to make the multiple leads in the lead frame 400 (refer to Figure 8 ) electrically independent leads, as Figure 10 illustrates, the frame portion 410 and the connecting rod 411 of the lead frame 400 are removed to separate the leads 4 into individual pieces. The removal of the frame portion 410 and the connecting rod 411 of the lead frame 400 can be carried out, for example, by a well-known method using a mold. After removing the frame portion 410 and the connecting rod 411 of the lead frame 400, for example, as Figure 11 shows, the external lead portion is bent at the bending position YLB in the external lead portion of the lead 4. The bending of the external lead portion is carried out as follows: at a position on the surface of the lead 4 that is exposed and located between the bending position YLB and the portion covered by the covering portion 750 of the sealing member 7, the lead 4 (external lead portion) is clamped from the up and down directions by the molds 18 and 19. In this state, the forming mold 20 is pressed against a position farther from the covering portion 750 than the bending position YLB. At this time, the external lead portion of the lead 4 is bent so as to extend from the bending position YLB in a direction opposite to the lower surface 703 of the metal layer 6A of the heat dissipation member 6 exposed by the sealing member 7 (the upper surface of the sealing member 7). In this way, by creating an interval on the surface of the lead 4 that is exposed between the bending position YLB of the external lead portion and the portion covered by the covering portion 750 of the sealing member 7, when the external lead portion is bent, it is possible to prevent bending stress from being generated in the covering portion 750 of the sealing member 7, resulting in damage or peeling of the covering portion 750. The bending angle of the external lead portion is not limited to Figure 2 、 Figure 11 such as the 90 degrees illustrated. The process of removing the frame portion 410 and the connecting rod 411 of the lead frame 400 and the process of bending the external lead portion of the lead 4 may be independent processes, or the removal and bending may be carried out continuously or simultaneously.

[0062] Thus, in the semiconductor module 1 of the present embodiment, a covering portion 750 that covers the external lead portions of the leads 4 extending from the main body portion 700 is integrally formed with the main body portion 700 of the sealing member 7 that seals the semiconductor elements 3A, 3B, etc. Therefore, compared with the case described in Patent Document 1 where the external lead portions of the leads are coated after being sealed with a sealing member and bent, the number of manufacturing processes is reduced, and the manufacturing cost of the semiconductor module can be lowered. In addition, after the covering portion 750 is integrally formed with the main body portion 700, the exposed portions of the external lead portions of the leads 4 (i.e., the portions not covered by the covering portion 750) are bent. Thus, for example, after shipment, the user of the semiconductor module 1 can bend the external lead portions of the leads 4 at a desired angle and adjust the bending angle to a desired angle, etc. In addition, the covering portion 750 covers the entire surface of the external lead portions of the leads 4 in the section from the boundary between the external lead portions and the internal lead portions to a position closer to the boundary than the bending position YLB. Therefore, compared with the structure described in Patent Document 1 where the entire lead portion is covered with a sealing resin, the amount of resin material used for forming the sealing member 7 can be reduced.

[0063] In addition, by integrally forming the covering portion 750 that covers the entire surface (upper surface, lower surface, side surface) of the external lead portions of the leads 4 with the main body portion 700 by transfer molding or the like, the creepage distance between the adjacent leads 4 and the creepage distance between the external lead portions of the leads 4 and the metal layer 6A of the heat dissipation member 6 can be extended by the covering portion 750. Therefore, compared with the case described in Patent Document 2 where a protrusion portion that contacts the side surface of one of the adjacent leads is formed, the creepage distance between the lead 4 and the metal layer 6A of the heat dissipation member 6 can be ensured, in particular. Moreover, since the surface of the external lead portions of the leads 4 is covered with the covering portion 750 having a thickness of about 1 mm to ensure the creepage distance, the amount of resin material used for forming the sealing member can be reduced compared with the case described in Patent Document 3 where a block-shaped protrusion portion extending from the upper surface to the lower surface of the main body portion is formed.

[0064] Figure 12 It is a bottom view for explaining a modified example of the shape of the covering portion. Figure 13 is Figure 12 a cross-sectional view taken along the dotted line C - C' of Figure 12 , Figure 13 Only the structure on the end face 701 side of the main body portion 700 of the sealing member 7 is illustrated in

[0065] In the semiconductor module 1 of the present embodiment, the covering portion 750 of the sealing member 7 only needs to be a member that individually covers each lead 4 and extends the creepage distance Dcr1 and / or Dcr2, and the shape of the covering portion 750 is not limited to a specific shape. Therefore, for example, as Figure 12 and Figure 13 shown, the shape of the covering portion 750 can also be set such that the thickness change of each surface of the lead 4 as observed in the extending direction extending from the main body portion 700, and the distance of the section along the surface of the covering portion 750 of the creepage distances Dcr1 and Dcr2 is longer than the length L1 (i.e., having a tapered portion). Figure 12 and Figure 13 As exemplified by, the side of the covering portion 750 closer to the main body portion 700 has thicknesses H1 and H2, and the side closer to the bending position of the lead 4 has thicknesses H4 (>H1) and H5 (>H2). Such a shape of the covering portion 750 can ensure longer creepage distances Dcr1 and Dcr2, for example, under the condition that the distance LL from the end face 701 of the main body portion 700 to the bending position YLB is constant. In addition, under the condition that the creepage distance Dcr1 between the leads 4 and the creepage distance Dcr2 between the lead 4 and the metal layer 6A of the heat sink member 6 are constant, the length L1 of the covering portion 750 along the extending direction (Y direction) of the external lead portion of the lead 4 can be shortened, and the distance LL from the end face 701 of the main body portion 700 to the bending position YLB can be shortened.

[0066] In addition, the shape of the covering portion 750 is not limited to Figure 12 and Figure 13 the shape in which the thickness continuously changes along the extending direction (Y direction) of the lead 4 as exemplified (i.e., having a tapered portion). The shape of the covering portion 750 can also be, for example, a shape in which the thickness changes stepwise along the extending direction (Y direction) of the lead 4.

[0067] In addition, in the semiconductor module 1 of the present embodiment, as Figure 13 exemplified, by forming a recess 705 on the lower surface 703 of the main body portion 700 of the sealing member 7, the creepage distance Dcr2 between the lead 4 and the metal layer 6A of the heat sink member 6 can be more reliably ensured. In addition, although not shown in the figure, for example, a recess that depresses toward the side opposite to the extending direction of the lead 4 can also be formed between adjacent covering portions 750 in the end face 701 of the main body portion 700 (between adjacent leads 4) to further extend the creepage distance Dcr1 between the leads 4. In addition, the covering portion 750 of the sealing member 7 can be formed to cover the lead 4 in the lead frame 400, for example, and integrated with the main body portion 700 of the sealing member 7 in the sealing process.

[0068] The semiconductor module 1 of the above-described embodiment can be applied, for example, to industrial power conversion devices such as motor-driven inverter devices for driving elevators, escalators, and air conditioning systems in buildings. In addition, the use of the semiconductor module 1 is not limited to a specific use. For example, the semiconductor module 1 can also be applied to power conversion devices such as inverter devices for driving motors of vehicles such as four-wheel vehicles and railway vehicles. In addition, as described above, the circuit formed in the semiconductor module 1 is not limited to a power conversion circuit that converts direct current to alternating current, and can also be other circuits.

[0069] Hereinafter, the characteristic points in the above-described embodiment will be summarized.

[0070] The semiconductor module of the above-described embodiment includes: a semiconductor element; a sealing member having a main body portion that seals the semiconductor element; and a plurality of leads, each having an internal lead portion extending within the main body portion of the sealing member and an external lead portion extending outside the main body portion and bent at a prescribed bending position. The sealing member has a covering portion that individually covers the entire surface of the interval of the external lead portion of the lead from the boundary with the internal lead portion to a position closer to the boundary than the bending position for each interval of the external lead portion.

[0071] In the semiconductor module of the above-described embodiment, the main body portion of the sealing member and the covering portion are integrally formed.

[0072] The semiconductor module of the above-described embodiment further includes an element mounting member that mounts the semiconductor element, and a surface of the element mounting member on the side opposite to the surface on which the semiconductor element is mounted is exposed from the main body portion of the sealing member.

[0073] In the semiconductor module of the above-described embodiment, the element mounting member has: a chip pad that mounts the semiconductor element; and a heat dissipation member that is disposed on the side opposite to the semiconductor element with the chip pad as a boundary and is connected to the chip pad, and the heat dissipation member is exposed from the main body portion of the sealing member.

[0074] In the semiconductor module of the above-described embodiment, the main body portion of the sealing member is formed of the same insulating material as the covering portion.

[0075] In the semiconductor module of the above-described embodiment, the main body portion of the sealing member includes: a housing member having a space for accommodating the semiconductor element and integrated with the lead in such a manner that a part of the internal lead portion of the lead is exposed in the space; and an insulating member filled in the space of the housing member.

[0076] In the semiconductor module of the above-described embodiment, the covering portion of the sealing member is integrally formed with the housing member.

[0077] The semiconductor module of the above-described embodiment further includes an element mounting member that mounts the semiconductor element, and the housing member and the element mounting member are joined by the insulating member filled in the space of the housing member such that a surface on a side opposite to a surface on which the semiconductor element is mounted in the element mounting member is exposed from the main body portion.

[0078] The semiconductor module of the above-described embodiment further includes a cooler that is connected to the element mounting member, and an external lead portion of the lead extends outward from an end surface of an end portion of the main body portion of the sealing member that is located in a direction parallel to the in-plane direction of the surface on which the element mounting member is exposed, and a portion of the external lead portion from the bending position to an end portion on a side opposite to a boundary between the external lead portion and the internal lead portion is bent away from the cooler.

[0079] In the semiconductor module of the above-described embodiment, a thickness of a side of the covering member closer to the bending position is thicker than a thickness of a side closer to a boundary between the external lead portion and the internal lead portion.

[0080] The semiconductor module of the above-described embodiment has a recess formed in a surface of the main body portion of the sealing member where the element mounting member is exposed.

[0081] The semiconductor module of the above-described embodiment forms a power conversion circuit including the semiconductor element in the main body portion of the sealing member.

[0082] Furthermore, the present invention is not limited to the above-described embodiment, and various changes, replacements, and deformations can be made without departing from the gist of the technical idea. In addition, if the technical idea can be implemented in other ways due to technological progress or other derived technologies, those methods can also be used for implementation. Therefore, the claims cover all embodiments that can be included within the scope of the technical idea.

[0083] Industrial Applicability

[0084] As described above, the present invention can suppress an increase in the manufacturing cost of the semiconductor module and the enlargement of the semiconductor module due to an increase in the creepage distance related to insulation performance. In particular, it is advantageous for use in a high-voltage power conversion device (inverter device).

Claims

1. A semiconductor module, wherein, the semiconductor module includes: a semiconductor element; a sealing member having a main body portion that seals the semiconductor element; and a plurality of leads, each having an internal lead portion extending within the main body portion of the sealing member and an external lead portion extending outside the main body portion and bent at a prescribed bending position, the sealing member has a covering portion that individually covers the entire surface of an interval of the external lead portion of the lead, from the boundary with the internal lead portion to a position closer to the boundary than the bending position, for each interval of the external lead portion.

2. The semiconductor module according to claim 1, wherein, the main body portion of the sealing member and the covering portion are integrally formed.

3. The semiconductor module according to claim 1, wherein, the semiconductor module further includes a component mounting member that mounts the semiconductor element, a surface of the component mounting member on a side opposite to the surface on which the semiconductor element is mounted is exposed from the main body portion of the sealing member.

4. The semiconductor module according to claim 3, wherein, the component mounting member has: a chip pad that mounts the semiconductor element; and a heat dissipation member that is disposed on a side opposite to the semiconductor element with the chip pad as a boundary and is connected to the chip pad, and the heat dissipation member is exposed from the main body portion of the sealing member.

5. The semiconductor module according to claim 1, wherein, the main body portion of the sealing member is formed of the same insulating material as the covering portion.

6. The semiconductor module according to claim 1, wherein, the main body portion of the sealing member includes: a housing member having a space for accommodating the semiconductor element, and integrated with the lead in such a manner that a part of the internal lead portion of the lead is exposed in the space; and an insulating member filled in the space of the housing member.

7. The semiconductor module according to claim 6, wherein, the covering portion of the sealing member and the housing member are integrally formed.

8. The semiconductor module according to claim 6, wherein, the semiconductor module further includes a component mounting member that mounts the semiconductor element, the housing member and the component mounting member are joined by the insulating member filled in the space of the housing member in such a manner that a surface of the component mounting member on a side opposite to the surface on which the semiconductor element is mounted is exposed from the main body portion.

9. The semiconductor module according to claim 3, wherein, the semiconductor module further includes a cooler connected to the component mounting member, the external lead portion of the lead extends outward from an end face of an end portion of the main body portion of the sealing member located in a direction parallel to the in-plane direction of the surface on which the component mounting member is exposed. The outer lead portion of the lead is bent away from the cooler at a portion from the bending position to the end portion on the side opposite to the boundary between the outer lead portion and the inner lead portion.

10. The semiconductor module according to claim 1, wherein the thickness of the covering member on the side closer to the bending position is thicker than the thickness on the side closer to the boundary between the outer lead portion and the inner lead portion.

11. The semiconductor module according to claim 3, wherein a recess is formed on the surface of the main body portion of the sealing member where the element mounting member is exposed.

12. The semiconductor module according to any one of claims 1 to 11, wherein a power conversion circuit including the semiconductor element is formed within the main body portion of the sealing member.

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