Semiconductor module

Abstract

To suppress an increase in manufacturing costs of semiconductor modules due to the increase in creepage distance, which is related to insulation performance.SOLUTION: A semiconductor module (1) includes: 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 within 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. Therein the sealing member has a covering portion (750) that individually covers, for each section of the outer lead portion, an entire surface of the outer lead portion of the lead from a boundary between the inner lead portion and the outer leading portion to a position closer to the boundary than the bending position.SELECTED DRAWING: Figure 3

Description

[Technical Field]

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

[0002] In some DIP (Dual Inline Package) type semiconductor modules, the outer lead portions of the leads are coated with a coating material that is different from the sealing material that seals the semiconductor element in order to increase the creepage distance, which is related to insulation performance (see, for example, Patent Document 1). Also, in some DIP (Dual Inline Package) type semiconductor modules, protrusions that protrude between the leads are formed on the sealing material in order to increase the creepage distance between the leads (see, for example, Patent Documents 2 and 3). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-53611 [Patent Document 2] Japanese Patent Application Laid-Open No. 2013-84838 [Patent Document 3] Japanese Patent Application Publication No. 6-61375 Summary of the Invention [Problem to be solved by the invention]

[0004] When the creepage distance is increased by the above-mentioned method, the manufacturing cost increases due to an increase in the number of manufacturing steps and an increase in the amount of material used.

[0005] In one aspect, the present invention aims to suppress an increase in the manufacturing cost of a semiconductor module due to an increase in creepage distance, which is related to insulation performance. [Means for solving the problem]

[0006] A semiconductor module according to one embodiment comprises a semiconductor element, a sealing member having a main body portion that seals the semiconductor element, and a plurality of leads, each having an inner lead portion extending within 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, and the sealing member has a covering portion that individually covers the entire surface of the section of the outer lead portion of the lead from the boundary with the inner lead portion to a position closer to the boundary than the bending position, for each section of the outer lead portion. [Effects of the Invention]

[0007] According to the above-described aspect, 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 insulation performance. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 2 is a bottom view of the semiconductor module according to the embodiment. [Figure 2] 2 is a cross-sectional view illustrating a first example of the configuration inside the sealing member in the semiconductor module of FIG. 1. FIG. [Figure 3] 1. FIG. 4 is a cross-sectional view illustrating a second example of the configuration inside the sealing member in the semiconductor module of FIG. [Figure 4] 2 is a circuit diagram illustrating an example of a circuit configuration of the semiconductor module of FIG. 1. [Figure 5] 2 is an enlarged perspective view of the periphery of a covered portion in the semiconductor module of FIG. 1. FIG. [Figure 6] 1A to 1C are diagrams (part 1) illustrating a method for manufacturing a semiconductor module according to an embodiment. [Figure 7] 10A to 10C are diagrams (part 2) illustrating a method for manufacturing a semiconductor module according to an embodiment. [Figure 8] 10A and 10B are diagrams illustrating the relationship between a lead frame and a cavity of a mold. [Figure 9] 9 is a cross-sectional view taken along the dashed dotted line BB' in FIG. 8. [Figure 10]10A and 10B are bottom views illustrating an example of a process for dividing the leads into individual pieces. [Figure 11] 10A and 10B are front views illustrating an example of a process for bending outer lead portions. [Figure 12] 10A and 10B are bottom views illustrating modified examples of the shape of the covering portion. [Figure 13] 13 is a cross-sectional view taken along the dashed dotted line CC' in FIG. 12. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following description, a "semiconductor module" refers to a semiconductor element (semiconductor chip) sealed with an insulating material, and is also sometimes called a "semiconductor device" or "semiconductor package."

[0010] The X-axis, Y-axis, and Z-axis in each of the referenced figures are shown for the purpose of defining planes and directions in the semiconductor module shown. The X-axis, Y-axis, and Z-axis are perpendicular 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. Furthermore, when relating the X-axis, Y-axis, and Z-axis to the arrow directions (positive and negative) of the X-axis, Y-axis, and Z-axis shown in the figures, the X-axis, Y-axis, and Z-axis directions are labeled as the "positive side" or "negative side."

[0011] In this specification, the Z direction may be referred to as the up-down direction. In this specification, "up" and "above" refer to the positive side of the Z direction relative to a reference surface, component, position, etc., and "down" and "below" refer to the negative side of the Z direction relative to a reference surface, component, position, etc. For example, when describing "component B being placed on component A," component B is placed on the positive side of component A in the Z direction. Furthermore, when describing "the top surface of component A," this surface includes the surface located at the end of component A on the positive side of the Z direction and facing the positive side of the Z direction. These directions and surfaces associated with these directions are terms used for convenience of explanation, and their correspondence with the X-axis, Y-axis, and Z-axis directions may change depending on the mounting orientation of the semiconductor module, etc. For example, in this specification, the surface of a semiconductor element facing the die pad is referred to as the bottom surface, and the surface opposite the bottom surface is referred to as the top surface. However, this is not limited thereto; the surface facing the die pad may be referred to as the top surface, and the surface opposite the top surface may be referred to as the bottom surface.

[0012] The aspect ratios and relative sizes of components in each diagram are merely schematic representations and do not necessarily correspond to the relationships in an actually manufactured semiconductor module. For the sake of convenience, the relative sizes of components may be exaggerated. Furthermore, for the sake of convenience, some cross-sectional views show the cross-sectional configuration of a semiconductor module cut along an imaginary cutting line that cannot be accurately shown in a plan view.

[0013] In this specification, the terms "not shown," "not shown," "not shown," and the like are intended to indicate without using a specific reference symbol or a leading line which part in the figure corresponds to the component to which the term is attached. For example, "first main electrode not shown" indicates both that a part (e.g., a shape, a line, etc.) representing the first main electrode is not shown in the figure and that there is no reference symbol or leading line clearly indicating the part corresponding to the first main electrode in the figure. Furthermore, an underlined reference symbol in the figure indicates the entire component including multiple parts distinguished by multiple reference symbols.

[0014] The semiconductor module exemplified in the following description may be applied to a power conversion device such as an inverter device for industrial or electrical equipment (e.g., an in-vehicle motor). For this reason, the following description will omit detailed descriptions of configurations, functions, operations, manufacturing methods, etc. that are identical to or similar to those of known semiconductor modules.

[0015] Fig. 1 is a bottom view of a semiconductor module according to an embodiment. Fig. 2 is a cross-sectional view illustrating a first configuration example within a sealing member in the semiconductor module of Fig. 1. Fig. 3 is a cross-sectional view illustrating a second configuration example within a sealing member in the semiconductor module of Fig. 1. The cross-sectional views of Figs. 2 and 3 show cross-sectional configuration examples of the semiconductor module 1 taken along a virtual cutting line connecting a dashed dotted line A passing through one lead located on the negative side in the Y direction of the semiconductor module 1 of Fig. 1 and another dashed dotted line A' passing through another lead located on the positive side in the Y direction.

[0016] The semiconductor module 1 illustrated in FIGS. 1 to 3 includes a die pad 2, semiconductor elements 3A and 3B, leads 4 (4A to 4X), bonding wires 5 (5A and 5B), a heat dissipation member 6, and a sealing member 7. The semiconductor module 1 may include a cooler 8 (see FIG. 2) located below the heat dissipation member 6. However, in this specification, the semiconductor module 1 refers to a DIP (Dual Inline Package) type semiconductor package excluding the cooler 8 illustrated in FIGS. 2 and 3. Furthermore, in this specification, when referring to a specific lead among the multiple leads 4A to 4X, the reference numeral (any of 4A to 4X) assigned to that specific lead in FIG. 1 is used; otherwise, the reference numeral is simply referred to as "lead 4." Similarly, when referring to a specific bonding wire among the multiple bonding wires 5A and 5B, the reference numeral (any of 5A or 5B) assigned to that specific bonding wire in FIG. 2 or the like is used; otherwise, the reference numeral is simply referred to as "bonding wire 5."

[0017] The die pad 2 is a component on which a semiconductor element 3A, sometimes called a semiconductor chip or die, is mounted. The semiconductor element 3A may be, for example, an RC (Reverse Conducting)-IGBT (Insulated Gate Bipolar Transistor) element, which is a switching element, and an RC (Reverse Conducting)-IGBT element, which integrates the functions of an IGBT (Insulated Gate Bipolar Transistor) element, which is a switching element, and a diode element such as an FWD (Free Wheeling Diode) element connected in antiparallel to the IGBT element. The semiconductor element 3A may also be, for example, a MOSFET (Metal Oxide Semiconductor Field Effect Transistor) element, which is a switching element. This type of semiconductor element 3A has a first main electrode (not shown) on its bottom surface and a second main electrode and a control electrode (gate electrode) (not shown) on its top surface. When the switching element of the semiconductor element 3A is an IGBT element, the first main electrode on the bottom surface may be called a collector electrode, and the second main electrode on the top surface may be called an emitter electrode. The semiconductor substrate on which the switching element and diode element in the semiconductor element 3A are formed is not limited to a silicon substrate, but may be a substrate using a wide band gap semiconductor such as a SiC (silicon carbide) substrate or a GaN (gallium nitride) substrate.

[0018] The semiconductor element 3A is bonded to the upper surface of the die pad 2 by a bonding material 9A such as solder, and a first main electrode is electrically connected to the die pad 2. The die pad 2 is electrically connected to a lead 4 (any of 4Q to 4X) extending from the sealing member 7 to the positive side in the Y direction by a bonding wire 5A. A second main electrode of the semiconductor element 3A is electrically connected to another lead 4 (any of 4Q to 4X not connected to the bonding wire 5A) extending from the sealing member 7 to the positive side in the Y direction by a bonding wire (not shown). A control electrode of the semiconductor element 3A is electrically connected to the semiconductor element 3B, which is a control IC, by a bonding wire 5B, for example. The semiconductor element 3B is bonded to the upper surface of a portion of the lead 4 (inner lead portion) embedded in the sealing member 7 by a bonding material. The number and type of semiconductor elements bonded to the upper surface of the die pad 2 and the upper surfaces of the inner lead portions are not limited to a specific number or type. For example, the semiconductor element functioning as the IGBT element and the semiconductor element functioning as the diode element may be bonded to the upper surface of the die pad 2 so as to be connected in anti-parallel.

[0019] A heat dissipation member 6 is connected to the underside of the die pad 2. The heat dissipation member 6 includes a metal layer 6A exposed from the underside 703 of the sealing 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 made of copper, aluminum, or the like. The insulating layer 6B may be a ceramic substrate formed of a ceramic material such as aluminum oxide (Al2O3), aluminum nitride (AlN), silicon nitride (Si3N4), or a composite material of aluminum oxide (Al2O3) and zirconium oxide (ZrO2). The insulating layer 6B may be, for example, a substrate formed of an insulating resin such as epoxy resin, a substrate formed by impregnating a base material such as glass fiber with an insulating resin, or a substrate formed 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 in which a metal layer is also 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 die pad 2, or may be a metal plate or metal foil separate from the die pad 2. The set of the die pad 2 and the heat dissipation member 6 is an example of an element mounting member on which a semiconductor element is mounted.

[0020] The die pad 2, the semiconductor elements 3A and 3B, the bonding wires 5, and the connection portions of the leads 4 with the bonding wires 5 and the surrounding areas thereof (hereinafter referred to as "inner lead portions") are sealed with a sealing member 7. The sealing member 7 in the semiconductor module 1 according to this embodiment has a main body portion 700 and a covering portion 750. The main body portion 700 is a roughly rectangular portion that seals the die pad 2, the semiconductor elements 3A and 3B, the bonding wires 5, and the inner lead portions of the leads 4 so that the lower surface (metal layer 6A) of the heat dissipation member 6 is exposed. The covering portion 750 is a roughly cylindrical portion that covers the portions of the leads 4 that extend outward from the main body portion 700 (hereinafter referred to as "outer lead portions") for each outer lead portion.

[0021] As described above, the semiconductor module 1 of this embodiment is a DIP-type semiconductor package, and the leads 4 extend outward from end faces 701 and 702 located at ends in a direction (Y direction) parallel to the in-plane direction of the bottom surface 703 of the main body portion 700 of the sealing member 7. The leads 4A to 4P (for control signals) extend from end face 701 on the negative side of the Y direction of the main body portion 700 to the negative side of the Y direction, and the leads 4Q to 4X (for main current) extend from end face 702 on the positive side of the Y direction of the main body portion 700 to the positive side of the Y direction. The leads 4 of the semiconductor module 1 are bent at a bending position in the outer lead portion, as shown in FIGS. 2 and 3 , for example. The section of the outer lead portion from the bending position to the end on the opposite side from the boundary with the inner lead portion is bent from the bending position toward the top surface of the main body portion 700 (positive side of the Z direction). In other words, the outer lead portions of the leads 4 are bent in a direction away from the cooler 8 when the cooler 8 is connected to the underside of the semiconductor module 1. The cooler 8 is thermally connected to the metal layer 6A of the heat dissipation member 6 exposed from the underside 703 of the sealing member 7 via a thermally conductive member 9B such as thermal grease or thermal compound. The cooler 8 may be a device that dissipates heat generated by the semiconductor element 3A by circulating a refrigerant such as cooling water. The cooler 8 may also be a device that dissipates heat generated by the semiconductor element 3A into the air, such as a heat sink.

[0022] 2, the main body portion 700 of the sealing member 7 is composed of a case member 710 having a space for accommodating the semiconductor elements 3A, 3B, etc., and an insulating filler member 720 that fills the space in the case member 710. In this case, the leads 4 are integrated with the case member 710 so that a portion of the inner lead portion is exposed in the space in the case member 710 that accommodates the semiconductor elements 3A, 3B, etc., and are supported by the case member 710. In the semiconductor module 1 having the case member 710, the set of the die pad 2 serving as an element mounting member and the heat dissipation member 6 is joined to the case member 710 by the filler member 720 so that the surface (the lower surface of the heat dissipation member 6) opposite to the surface on which the semiconductor element 3A is mounted (the upper surface of the die pad 2) is exposed from the main body portion 700. In the semiconductor module 1 illustrated in FIG. 2, a covering portion 750 is integrally formed individually for each lead 4 on each of an end surface 701 on the negative side in the Y direction and an end surface 702 on the positive side in the Y direction of the case member 710.

[0023] In addition, as shown in FIG. 3, the entire main body portion 700 of the sealing member 7 may be formed from the same insulating resin, and a covering portion 750 may be integrally formed individually for each lead 4 on each of the end face 701 on the negative side of the Y direction and the end face 702 on the positive side of the Y direction of the main body portion 700.

[0024] The semiconductor module 1 described above with reference to FIGS. 1 to 3 may be a module that includes a three-phase inverter circuit and a control circuit, which may be called an IPM (Intelligent Power Module).

[0025] Fig. 4 is a circuit diagram illustrating an example of the circuit configuration of the semiconductor module of Fig. 1. Fig. 4 illustrates only a portion of the three-phase inverter circuit and control circuit included in the semiconductor module 1.

[0026] The semiconductor module 1 includes a power conversion circuit that converts DC into three-phase AC (U-, V-, and W-phase) and outputs the converted AC. FIG. 4 illustrates a half-bridge inverter circuit that converts DC into U-phase AC. 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 to each of the two IGBT elements 10A and 10B. The first lead 4W is a P terminal connected to the positive electrode of a DC power supply, and the second lead 4S is an N (U) terminal connected to the negative electrode of the DC power supply. Of the two IGBT elements, the collector electrode of the IGBT element 10A in the upper arm 12A is connected to the first lead 4W, and the emitter electrode of the IGBT element 10B in the lower arm 12B is connected to the second lead 4S. An emitter electrode of IGBT element 10A of upper arm 12A and a collector electrode of IGBT element 10B of lower arm 12B are connected to third lead 4V, which is a U-phase AC output terminal. A gate of IGBT element 10A of upper arm 12A is connected to first control circuit 13A, and a gate of IGBT element 10B of lower arm 12B is connected to second control circuit 13B. Leads 4A to 4H extending from an end surface 701 of main body portion 700 of sealing member 7 to the negative side in the Y direction are connected to first control circuit 13A, and leads 4I to 4P extending from end surface 701 to the negative side in the Y direction are connected to second control circuit 13B.

[0027] The half-bridge inverter circuit that outputs DC as V-phase AC and the half-bridge inverter circuit that outputs W-phase AC may each have a circuit configuration similar to the half-bridge inverter circuit that outputs U-phase AC illustrated in Fig. 4. First control circuit 13A controls the voltages applied to the gates of IGBT elements 10A in upper arms 12A of U-phase, V-phase, and W-phase based on the drive power supply voltages and the like input from a plurality of leads 4A to 4H. Second control circuit 13B controls the voltages applied to the gates of IGBT elements 10B in lower arms 12B of U-phase, V-phase, and W-phase based on the drive power supply voltages and the like input from a plurality of leads 4I to 4P.

[0028] The circuit configuration of the semiconductor module 1 described above with reference to Fig. 4 is merely an example of the power conversion circuit formed in the main body portion 700 of the sealing member 7. The circuit formed in the main body portion 700 may be a power conversion circuit with a different circuit configuration. The circuit formed in the main body portion 700 may include a circuit other than the power conversion circuit, may form a part of the power conversion circuit, or may form only a circuit other than the power conversion circuit.

[0029] Fig. 5 is an enlarged perspective view of the periphery of the covered portion of the semiconductor module of Fig. 1. In the following explanation with reference to Fig. 5, only the configuration of the end face 701 side of the main body portion 700 of the sealing member 7 will be explained, but the configuration of the opposite end face 702 side may be similar.

[0030] As described above, in the semiconductor module 1 of this embodiment, the outer lead portions of the leads 4 extending from the main body portion 700 of the sealing member 7 are covered with the covering portion 750 for each lead 4. For example, as shown in Fig. 5 , the outer lead portions of the leads 4 are bent at a bending position YLB that is a predetermined distance from an end face 701 of the main body portion 700 of the sealing member 7 in the extension direction (Y direction) of the leads 4 (in other words, the boundary with the inner lead portion). The covering portion 750 is formed integrally with the main body portion 700, and covers the entire surface of the outer lead portion over a section of length L1 from the end face 701 of the main body portion 700 to a predetermined position that is closer to the end face 701 of the main body portion 700 than the bending position YLB.

[0031] 5, the thickness H1 of the covering portion 750 from the side surfaces 401, 402 of the outer lead portion is the same thickness. The side surfaces 401, 402 are surfaces of the outer lead portion that face the surfaces of adjacent outer lead portions extending from an end face 701 of the main body portion 700. Therefore, if the gap between adjacent covering portions 750 is G and the length of the covering portion 750 in the extension direction (Y direction) of the lead 4 is L1, the creepage distance Dcr1 between adjacent leads 4 (outer lead portions) extending from the end face 701 of the main body portion 700 is the sum of the gap G between adjacent covering portions 750, the thickness H1 of the covering portion 750 from the side surfaces 401, 402 of the outer lead portion, and the length L1 of each covering portion 750 that covers the adjacent leads 4. That is, the creepage distance Dcr1 between adjacent leads 4 (outer lead portions) extending from the end face 701 of the main body portion 700 is the sum of the length from the side surface 401 of the lead 4 (outer lead portion) to the side surface 402 of the adjacent lead 4 (outer lead portion) and the length L1 of each of the covering portions 750 covering the adjacent leads 4. Note that the thicknesses H1 of the illustrated covering portions 750 from the side surfaces 401, 402 of the outer lead portions are not limited to being the same thickness and may be different thicknesses. Furthermore, the length L1 of the covering portions 750 covering adjacent leads 4 may be different as long as the creepage distance can be ensured.

[0032] Furthermore, the thickness H2 of the covering portion 750 at the lower surface 403 and the upper surface (not shown) of the outer lead portion may be 1 mm or less. In contrast, the thickness of the main body portion 700 in the vertical direction (Z direction) may be several mm to several tens of mm. 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 at the lower surface 703 of the main body portion 700 is L2, and the distance from the lower surface 703 of the main body portion 700 to the covering portion 750 is H3, the creepage distance Dcr2 between the lead 4 (outer lead portion) and the metal layer 6A of the heat dissipation member 6 is 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 extension direction (Y direction) of the lead 4, and the thickness H1 from the side surfaces 401 and 402 of the outer lead portion.

[0033] That is, in the semiconductor module 1 of this embodiment, the sealing member 7 has a covering portion 750 that covers the outer lead portion of the lead 4, and therefore, compared to a semiconductor module not having the covering portion 750, the creepage distance between adjacent leads 4 (outer lead portions) can be increased by the total distance of the lengths L1 of the covering portions 750 that individually cover adjacent leads 4. Furthermore, compared to a semiconductor module not having the covering portion 750, the semiconductor module 1 of this embodiment can increase the creepage distance between the leads 4 (outer lead portions) and the metal layer 6A of the heat dissipation member 6 by the length L1 of the covering portion 750. Note that the covering portion 750 does not need to be provided on all of the leads 4A to 4X, and it need only be provided on those leads 4 for which a sufficient creepage distance is required. For example, the covering portion 750 may be provided on the leads 4Q to 4X for main current.

[0034] FIG. 6 is a diagram (part 1) illustrating a method for manufacturing a semiconductor module according to an embodiment. FIG. 7 is a diagram (part 2) illustrating a method for manufacturing a semiconductor module according to an embodiment. FIG. 8 is a diagram illustrating the relationship between a lead frame and a cavity of a mold. FIG. 9 is a cross-sectional view taken along the dashed dotted line B-B' in FIG. 8. FIGS. 6 and 7 illustrate a mold used in manufacturing a semiconductor module 1 in which the entire main body portion 700 illustrated in FIG. 3 is made of the same sealing resin.

[0035] The manufacturing method of the semiconductor module 1 according to this embodiment may be the same as that of a well-known DIP-type semiconductor package, but in the sealing step of sealing the 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. For this reason, in the sealing step, for example, transfer molding is performed using molds (upper mold 15 and lower mold 16) as shown in FIGS. 6 to 9. The illustrated upper mold 15 and lower mold 16 have recesses 1500 and 1600, respectively, formed so that a space (cavity) 17 corresponding to the outer shape of the sealing member 7 is defined around the semiconductor elements 3A, 3B, etc., to be sealed when the molds are clamped (see FIGS. 6 and 7). The upper mold 15 and lower mold 16 are formed with gates (not shown) for injecting an insulating material into the cavity 17 after clamping.

[0036] The recess 1500 of the upper mold 15 and the recess 1600 of the lower mold 16 used when manufacturing the semiconductor module according to this embodiment include first recesses 1501, 1601 for forming the main body portion 700 of the sealing member 7 and second recesses 1502, 1602 for forming the covering portion 750, respectively. As shown in FIGS. 8 and 9, the second recesses 1502, 1602 are individually formed for each lead 4 formed on the lead frame 400, and define an annular space with an exposed surface around the lead 4. Lead pressing portions 1503, 1603 are formed in the upper mold 15 and the lower mold 16 at positions facing the outer lead portions of the lead frame 400. The lead pressing portions 1503, 1603 clamp the lead frame 400 when the molds are clamped and prevent the insulating material that has flowed into the second recesses 1502, 1602 from leaking out.

[0037] At the time of carrying out the sealing process, the multiple leads 4 are in the state of lead frame 400, integrated by frame portion 410, tie bars 411, etc., and the portions that will become the outer lead portions of each lead 4 are not bent. Adjacent leads 4 in the lead frame 400 are connected to each other by tie bars 411, etc., at positions that do not overlap with cavity 17 that is defined when upper mold 15 and lower mold 16 are clamped together.

[0038] The shapes of the recess 1500 of the upper mold 15 and the recess 1600 of the lower mold 16 are not limited to a specific shape, as long as they define a space (cavity) 17 corresponding to the entire sealing member 7, including the main body portion 700 and the covering portion 750, when the molds are clamped around the lead frame 400. For example, the shapes of the recess 1500 of the upper mold 15 and the recess 1600 of the lower mold 16 may define a space for forming the case member 710 of the main body portion 700 and the covering portion 750 described above with reference to FIG. 2 when the molds are clamped. Furthermore, the second recesses 1502, 1602 for forming the covering portion 750 may be formed at positions corresponding to the leads 4 for which a longer creepage distance is desired. In other words, the second recesses 1502, 1602 for forming the covering portion 750 may be formed at positions corresponding to one or more of all the leads 4 (outer lead portions).

[0039] Fig. 10 is a bottom view illustrating an example of a process for dividing the leads into individual pieces. Fig. 11 is a front view illustrating an example of a process for bending the outer lead portions. Figs. 10 and 11 illustrate only the configuration of the end face 701 side of the main body portion 700 of the sealing member 7, but the configuration of the opposite end face 702 side may be the same.

[0040] After the encapsulation process, in order to separate the multiple leads of the lead frame 400 (see FIG. 8 ) into electrically independent leads, as illustrated in FIG. 10 , the frame 410 and tie bars 411 of the lead frame 400 are cut to separate the leads 4. Cutting the frame 410 and tie bars 411 of the lead frame 400 can be performed, for example, by a well-known method using a mold. After cutting the frame 410 and tie bars 411 of the lead frame 400, the outer lead portion of the lead 4 is bent at a bending position YLB in the outer lead portion, as shown in FIG. 11 , for example. The bending of the outer lead portion is performed by clamping the lead 4 (outer lead portion) between the bending position YLB and the portion covered by the covering portion 750 of the encapsulating member 7 from above and below with molds 18 and 19 at a position where the surface of the lead 4 is exposed, and then pressing a molding mold 20 against a position farther from the covering portion 750 than the bending position YLB. At this time, the outer 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 sealing member 7 where the metal layer 6A of the heat dissipation member 6 is exposed (toward the upper surface of the sealing member 7). In this way, by creating a section where the surface of the lead 4 is exposed between the bending position YLB of the outer lead portion and the portion covered by the covering portion 750 of the sealing member 7, bending stress is generated in the covering portion 750 of the sealing member 7 when the outer lead portion is bent, preventing damage or peeling of the covering portion 750. The bending angle of the outer lead portion is not limited to 90 degrees as illustrated in FIGS. 2 and 11. The process of cutting the frame portion 410 and the tie bars 411 of the lead frame 400 and the process of bending the outer lead portion of the lead 4 may be separate processes, or the cutting and bending may be performed successively or simultaneously.

[0041] As described above, in the semiconductor module 1 according to the present embodiment, the covering portion 750 that covers the outer lead portions of the leads 4 extending from the main body portion 700 of the sealing member 7 that seals the semiconductor elements 3A, 3B, etc. is integrally formed with the main body portion 700. This reduces the number of manufacturing steps and reduces the manufacturing cost of the semiconductor module compared to the case described in Patent Document 1, where the outer lead portions are coated after sealing with the sealing member and bending the outer lead portions of the leads. Furthermore, by bending the exposed portions of the outer lead portions of the leads 4 (i.e., the portions not covered by the covering portion 750) after integrally forming the covering portion 750 with the main body portion 700, users of the semiconductor module 1 can, for example, bend the outer lead portions of the leads 4 to a desired angle or adjust the bending angle after shipment. Furthermore, the covering portion 750 covers the entire surface of the outer lead portions of the leads 4 from the boundary with the inner lead portions to a position closer to the boundary than the bending position YLB. Therefore, compared to the structure described in Patent Document 1 in which the entire lead portion is covered with sealing resin, the amount of resin material used to form sealing member 7 can be reduced.

[0042] Furthermore, by integrally forming the covering portion 750, which covers the entire surface (top, bottom, and side surfaces) of the outer lead portion of the lead 4, with the main body portion 700 by transfer molding or the like, the covering portion 750 can increase the creepage distance between each lead 4 and adjacent leads 4 and the creepage distance between each lead 4 and the metal layer 6A of the heat dissipation member 6. Therefore, compared to the case in which a protrusion is formed in contact with the side surface of one of adjacent leads as described in Patent Document 2, it is possible to ensure a sufficient creepage distance, particularly between the lead 4 and the metal layer 6A of the heat dissipation member 6. Furthermore, because the creepage distance is ensured by covering the surface of the outer lead portion of the lead 4 with the covering portion 750 having a thickness of approximately 1 mm, the amount of resin material used to form the sealing member can be reduced compared to the case in which a block-shaped protrusion extending from the top to the bottom surface of the main body portion is formed as described in Patent Document 3.

[0043] Fig. 12 is a bottom view illustrating a modified example of the shape of the covering portion. Fig. 13 is a cross-sectional view taken along the dashed line CC' in Fig. 12. Figs. 12 and 13 illustrate only the configuration of the end face 701 side of the main body portion 700 of the sealing member 7, but the configuration of the opposite end face 702 side may be the same.

[0044] The covering portion 750 of the sealing member 7 in the semiconductor module 1 according to this embodiment may be configured to cover each lead 4 individually, increasing the creepage distances Dcr1 and / or Dcr2. The shape of the covering portion 750 is not limited to a specific shape. For this reason, the covering portion 750 may be configured, for example, as shown in FIGS. 12 and 13 , so that the thickness of each surface of the lead 4 measured in the direction extending from the main body portion 700 varies, and the distance along the surface of the covering portion 750 for the creepage distances Dcr1 and Dcr2 is longer than the length L1 (i.e., the covering portion 750 may have a tapered shape). The covering portion 750 illustrated in FIGS. 12 and 13 has thicknesses H1 and H2 on the side closer to the main body portion 700 and thicknesses H4 (>H1) and H5 (>H2) on the side closer to the bending position of the lead 4. This shape of the covering portion 750 may ensure longer creepage distances Dcr1 and Dcr2, for example, when the distance LL from the end face 701 of the main body portion 700 to the bending position YLB is constant. Furthermore, under the condition that the creepage distances Dcr1 and Dcr2 between the leads 4 and between the leads 4 and the metal layer 6A of the heat dissipation member 6 are constant, the length L1 of the covering portion 750 along the extension direction (Y direction) of the outer 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.

[0045] 12 and 13, the shape of the covering portion 750 is not limited to a shape in which the thickness changes continuously (i.e., has a tapered portion) along the extension direction (Y direction) of the lead 4. The shape of the covering portion 750 may be, for example, a shape in which the thickness changes stepwise along the extension direction (Y direction) of the lead 4.

[0046] 13, the semiconductor module 1 of this embodiment can more reliably ensure the creepage distance Dcr2 between the leads 4 and the metal layer 6A of the heat dissipation member 6 by forming recesses 705 on the lower surface 703 of the main body portion 700 of the sealing member 7. Although not shown, for example, recesses may be formed on the end surface 701 of the main body portion 700 between adjacent covering portions 750 (between adjacent leads 4) on the side opposite to the extending direction of the leads 4 to further increase the creepage distance Dcr1 between the leads 4. The covering portions 750 of the sealing member 7 may be formed so as to cover the leads 4 of the lead frame 400, for example, and may be integrated with the main body portion 700 of the sealing member 7 in the sealing process.

[0047] The semiconductor module 1 according to the above-described embodiment may be applied to industrial power conversion devices, such as inverter devices that drive motors in elevators, escalators, building air conditioning systems, etc. The use of the semiconductor module 1 is not limited to a specific application. For example, the semiconductor module 1 may also be applied to power conversion devices, such as inverter devices that drive motors in vehicles such as four-wheeled automobiles, railroad cars, etc. 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, but may be other circuits.

[0048] The features of the above-described embodiment will be summarized below.

[0049] The semiconductor module according to the above-described embodiment comprises a semiconductor element, a sealing member having a main body portion that seals the semiconductor element, and a plurality of leads each having an inner lead portion that extends within the main body portion of the sealing member and an outer lead portion that extends outside the main body portion and is bent at a predetermined bending position, and the sealing member has a covering portion that individually covers the entire surface of the section of the outer lead portion of the lead from the boundary with the inner lead portion to a position closer to the boundary than the bending position, for each section of the outer lead portion.

[0050] In the semiconductor module according to the above embodiment, the main body portion of the sealing member is integrally formed with the covering portion.

[0051] The semiconductor module according to the above embodiment further includes an element mounting member on which the semiconductor element is mounted, and the surface of the element mounting member opposite to the surface on which the semiconductor element is mounted is exposed from the main body portion of the sealing member.

[0052] In the semiconductor module according to the above embodiment, the element mounting member has a die pad on which the semiconductor element is mounted, and a heat dissipation member that is arranged on the opposite side of the die pad from the semiconductor element and is connected to the die pad, and the heat dissipation member is exposed from the main body portion of the sealing member.

[0053] In the semiconductor module according to the above embodiment, the main body portion of the sealing member is formed of the same insulating material as the covering portion.

[0054] In the semiconductor module according to the above embodiment, the main body portion of the sealing member has a space for accommodating the semiconductor element, and includes a case member integrated with the lead so that a portion of the inner lead portion of the lead is exposed in the space, and an insulating member filled in the space of the case member.

[0055] In the semiconductor module according to the above embodiment, the covering portion of the sealing member is integrally formed with the case member.

[0056] The semiconductor module according to the above embodiment further includes an element mounting member on which the semiconductor element is mounted, and the case member and the element mounting member are joined by the insulating member filled in the space of the case member so that the surface of the element mounting member opposite the surface on which the semiconductor element is mounted is exposed from the main body portion.

[0057] The semiconductor module according to the above embodiment further includes a cooler connected to the element mounting member, and the outer lead portion of the lead extends outward from an end face located at the end in a direction parallel to the in-plane direction of the surface of the main body portion of the sealing member where the element mounting member is exposed, and the portion from the bending position to the end opposite the boundary with the inner lead portion is bent in a direction away from the cooler.

[0058] In the semiconductor module according to the above embodiment, the covering member has a thickness on the side closer to the bending position that is greater than a thickness on the side closer to the boundary with the inner lead portion.

[0059] In the semiconductor module according to the above embodiment, a recess is formed in the surface of the main body of the sealing member where the element mounting member is exposed.

[0060] In the semiconductor module according to the above embodiment, the power conversion circuit including the semiconductor element is formed within the main body portion of the sealing member.

[0061] The present invention is not limited to the above-described embodiments, and may be variously modified, substituted, or altered without departing from the spirit of the technical idea. Furthermore, if the technical idea can be realized in a different way due to technological advances or other derived technologies, it may be implemented using that method. Therefore, the claims cover all embodiments that may fall within the scope of the technical idea. [Industrial Applicability]

[0062] As described above, the present invention can suppress increases in the manufacturing costs of semiconductor modules and increases in the size of semiconductor modules that are caused by increasing the creepage distance related to insulation performance, and is particularly advantageous when applied to high-voltage power conversion devices (inverter devices). [Explanation of symbols]

[0063] 1. Semiconductor module 2 die pad 3A, 3B semiconductor device 4, 4A~4Q Lead 401, 402 Side 403 Bottom surface 5, 5A, 5B Bonding Wire 6 Heat dissipation material 6A metal layer 6B Insulation layer 7 Sealing member 700 Main body part 701, 702 end face 703 Bottom surface 710 Case material 720 Filler material 750 Covered part 8 Cooler 9A Bonding material 9B Thermal conductive material 10A, 10B IGBT element 11A, 11B Diode elements 13A, 13B control circuit 15 Upper mold 16 Lower mold 1500, 1600 recess 17 Cavity 18~20 mold YLB bending position

Claims

1. A semiconductor element; a sealing member having a main body portion that seals the semiconductor element; a plurality of leads each having an inner lead portion extending within 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 has a covering portion that covers the entire surface of the outer lead portion of the lead in a section from the boundary with the inner lead portion to a position closer to the boundary than the bending position, for each section of the outer lead portion; Semiconductor module.

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

3. an element mounting member on which the semiconductor element is mounted, 2. The semiconductor module according to claim 1, wherein a surface of said element mounting member opposite to a surface on which said semiconductor element is mounted is exposed from said main body portion of said sealing member.

4. 4. The semiconductor module according to claim 3, wherein the element mounting member has a die pad on which the semiconductor element is mounted and a heat dissipation member connected to the die pad and arranged on the opposite side of the die pad from the semiconductor element, and the heat dissipation member is exposed from the main body portion of the sealing member.

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

6. The body portion of the sealing member a case member having a space for accommodating the semiconductor element, the case member being integrated with the leads so that a portion of the inner lead portion of the leads is exposed in the space; The semiconductor module according to claim 1 , further comprising an insulating member filled in the space of the case member.

7. 7. The semiconductor module according to claim 6, wherein the covering portion of the sealing member is integrally formed with the case member.

8. an element mounting member on which the semiconductor element is mounted, 7. The semiconductor module according to claim 6, wherein the case member and the element mounting member are joined by the insulating member filled in the space of the case member so that a surface of the element mounting member opposite to a surface on which the semiconductor element is mounted is exposed from the main body portion.

9. a cooler connected to the element mounting member, The outer lead portion of the lead is the sealing member extends outward from an end surface of the main body portion of the sealing member that is located at an end in a direction parallel to an in-plane direction of the surface on which the element mounting member is exposed, 4. The semiconductor module according to claim 3, wherein a portion from the bending position to an end opposite to a boundary with the inner lead portion is bent in a direction away from the cooler.

10. 2. The semiconductor module according to claim 1, wherein the thickness of the covering member on the side closer to the bending position is greater than the thickness of the covering member on the side closer to the boundary with the inner lead portion.

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

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

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