Semiconductor module

Abstract

To reduce variation in the parallelism between the external terminal part of the lead of each semiconductor module and the surface of a case.SOLUTION: A semiconductor module (1) includes: a wiring board (300) and a circuit component including a semiconductor element (320); a lead (5) joined to a conductor pattern (302) of the circuit component; and a case (4) having a nut (7) housed in a recess provided in a front surface (421). The case includes a frame part (400) surrounding the wiring board and a lid part (440) closing an opening of the frame part. The lead has an external terminal part (501) extending along the wiring board, a joined part (500) joined to the conductor pattern, and intermediate parts (502, 503) connecting the joined part and the external terminal part. The case is provided with contact portions (401, 402 / 423, 442) that come into contact with the lead to prevent increase in the angle of the extension direction of the external terminal part of the lead relative to the wiring board due to rotation of the lead about a boundary between the joined part and the intermediate part as a fulcrum.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[0002] Some semiconductor modules used in inverter devices have leads, one end of which is joined to a conductor of a circuit component arranged inside the case and the other end of which extends outward through a gap in the case. Some of these semiconductor modules are designed to enable highly accurate alignment between the case and an external terminal portion of the lead that extends outward from the case (for example, see Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2017 / 122473 [Patent Document 2] Japanese Patent Application Laid-Open No. 2009-21286 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the semiconductor modules described above, the parallelism between the external terminals of the leads and the surface (front surface) of the case tends to vary from one semiconductor module to another. One of the objects of the present invention is to reduce the variation in the parallelism between the external terminals of the leads and the surface (front surface) of the case from one semiconductor module to another. [Means for solving the problem]

[0005] A semiconductor module according to one embodiment includes a circuit component including a wiring board and a semiconductor element mounted on the wiring board, leads joined to conductor patterns of the circuit component, and a case having a recess on its front surface that houses a nut. The case includes a frame surrounding the wiring board and a lid closing an opening in the frame. The leads have external terminals extending along the wiring board, bonded portions joined to the conductor patterns, and intermediate portions connecting the bonded portions to the external terminals. The case includes a contact portion that contacts the leads to prevent an increase in the angle of the extension direction of the external terminals of the leads relative to the wiring board due to rotation of the intermediate portions of the leads and the external terminals around the boundary between the bonded portions and the intermediate portions. [Effects of the Invention]

[0006] According to the above-described aspect, it is possible to reduce variations in the parallelism between the external terminal portions of the leads and the surface (front surface) of the case for each semiconductor module. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a plan view of a semiconductor module according to a first embodiment. [Figure 2] FIG. 2 is a cross-sectional view taken along line AA' in FIG. [Figure 3] FIG. 10 is a perspective view illustrating an example of the shape of a lead. [Figure 4] 2 is a partially enlarged plan view showing an area B in FIG. 1. FIG. [Figure 5] FIG. 5 is a cross-sectional view taken along the line CC' in FIG. [Figure 6] 2 is an equivalent circuit diagram of an inverter circuit formed in the semiconductor module of FIG. 1. [Figure 7] FIG. 3 is a flow chart illustrating a manufacturing process of the semiconductor module according to the first embodiment. [Figure 8] 10A and 10B are diagrams illustrating the lifting of the main terminal. [Figure 9] FIG. 10 is a plan view of a semiconductor module according to a second embodiment. [Figure 10] 10 is a partially enlarged plan view of an area D in FIG. 9. FIG. [Figure 11] FIG. 11 is a cross-sectional view taken along the line EE' in FIG. [Figure 12] FIG. 10 is a flow chart illustrating a manufacturing process of the semiconductor module according to the second embodiment. [Figure 13] 10A to 10C are diagrams illustrating the effects of the configuration of the semiconductor module according to the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] 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, which may also be called a semiconductor chip or die, sealed with an insulating material. The semiconductor module may also be called a "semiconductor device."

[0009] The X-axis, Y-axis, and Z-axis in the drawings are shown for the purpose of defining planes and directions in the illustrated semiconductor module, etc. 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, the direction parallel to the Y-axis, and the direction parallel to the Z-axis will be referred to as the X-direction, the Y-direction, and the Z-direction, respectively. Furthermore, when each of the X-direction, Y-direction, and Z-direction is associated with the direction of the arrows (positive and negative) of the X-axis, Y-axis, and Z-axis shown in the drawings, it will be referred to as the "positive side" or "negative side."

[0010] 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 may be 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 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 wiring board 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 wiring board may be referred to as the top surface, and the opposite surface may be referred to as the bottom surface.

[0011] The aspect ratios and relative sizes of components in each figure 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 or may differ from the external shapes of components used in an actual semiconductor module. Also, underlined symbols in the figures indicate the symbols for the entire component, including multiple parts distinguished by multiple symbols.

[0012] In this specification, the terms "not shown," "not shown," "not shown," etc. are intended to indicate without using a specific reference symbol or a leading line which part in the drawing 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 drawing and that there is no reference symbol or leading line that clearly indicates the part corresponding to the first main electrode in the drawing.

[0013] 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.

[0014] [First embodiment] FIG. 1 is a plan view of a semiconductor module according to an embodiment. FIG. 2 is a cross-sectional view taken along line A-A' in FIG. 1. FIG. 3 is a perspective view illustrating an example of the shape of a lead. FIG. 4 is a partially enlarged plan view of an area B in FIG. 1. FIG. 5 is a cross-sectional view taken along line C-C' in FIG. 4. FIG. 6 is an equivalent circuit diagram of an inverter circuit formed in the semiconductor module of FIG. 1. Note that FIGS. 1 and 4 illustrate the semiconductor module in a state where the lid of the case 4 is not attached.

[0015] The semiconductor module 1 illustrated in FIGS. 1 to 5 includes a heat dissipation base 2, a circuit component 3, a case 4, and leads 5. In this specification, when it is necessary to distinguish between multiple identical components referenced by the same numerical reference, a reference symbol consisting of a number followed by an alphabetic character is used; when no distinction is required, only the numerical reference symbol is used. For example, when referring to a specific circuit component among four circuit components 3A to 3D, the reference symbol (any of 3A to 3D) assigned to that specific circuit component in the drawings is used; otherwise, the component is simply referred to as "circuit component 3."

[0016] The circuit components 3 are disposed on the upper surface of the heat dissipation base 2 and may include a wiring board 300 and a semiconductor element (semiconductor chip) 320. The heat dissipation base 2 is a plate-like member that dissipates heat generated by the circuit components 3, and may be a metal plate made of, for example, copper or aluminum. The heat dissipation base 2 may have a plurality of fins on its lower surface. The heat dissipation base 2 may be a part of the cooler 6, or may be a component connected to the cooler 6. In other words, the cooler 6 is an optional component of the semiconductor module 1 of this embodiment.

[0017] Wiring board 300 includes insulating substrate 301, multiple conductor patterns including conductor pattern 302 disposed on the upper surface of insulating substrate 301, and heat dissipation pattern 303 disposed on the lower surface of insulating substrate 301. Wiring board 300 may be, but is not limited to, a DCB (Direct Copper Bonding) substrate or an AMB (Active Metal Brazing) substrate. Insulating substrate 301 may be a ceramic substrate formed from 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). Insulating substrate 301 may also be a substrate formed by molding an insulating resin such as epoxy resin into a sheet, a substrate formed by impregnating a base material such as glass fiber with insulating resin, or a substrate formed by coating the surface of a flat metal core with insulating resin.

[0018] A plurality of conductor patterns, including conductor pattern 302, arranged on the upper surface of insulating substrate 301 are used as wiring members in electronic circuits, such as an inverter circuit, formed within semiconductor module 1. To conductor pattern 302, a joint portion 500 of lead 5 and an electrode (not shown) on the underside of semiconductor element 320 are joined. Joined portion 500 of lead 5 is joined to conductor pattern 302, for example, by ultrasonic bonding. An electrode on the underside of semiconductor element 320 is joined to conductor pattern 302, for example, by a joining material such as solder. Heat dissipation pattern 303, arranged on the lower surface of insulating substrate 301, is used as a thermal conductive member that conducts heat generated by semiconductor element 320 to heat dissipation base 2 during operation of semiconductor module 1. The plurality of conductor patterns, including conductor pattern 302, and heat dissipation pattern 303 are formed of, for example, a metal foil such as copper or aluminum. Heat dissipation pattern 303 of wiring board 300 is thermally connected to the upper surface of heat dissipation base 2 by a bonding material such as solder, or by a heat conductive material such as thermal grease or thermal compound.

[0019] A case 4 for accommodating the circuit component 3 is also arranged on the upper surface of the heat dissipation base 2. The case 4 includes a frame body 400 having openings on the upper and lower surfaces, and nut grooves 420 (420A to 420C) and a lid 440 arranged on the upper surface of the frame body 400. The nut groove 420 is an insulating component having a recessed nut accommodating portion 422 for accommodating a nut 7 on its upper surface 421, which is the front surface of the case 4. The frame body 400, the nut grooves 420, and the lid 440 are formed from insulating resins with high electrical insulation, heat resistance, and dimensional stability, such as epoxy resin or polyphenylene sulfide (PPS) resin. The nut grooves 420 and the lid 440 are arranged on the upper surface of the frame body 400 so as to create a gap between the bonded portion 500 and the external terminal portion 501 of the lead 5 bonded to the conductive pattern 302 to extend outside the case 4. Frame body 400 of case 4 according to this embodiment has beams 401 and protrusions 402 provided on its inner peripheral wall surface. Beams 401 are portions that come into contact with the upper surfaces of arm portions 508 of third lead 5C, and protrusions 402 are portions that come into contact with the upper surfaces of protrusions 509 of third lead 5C.

[0020] The external terminal portion 501 of the lead 5 may be a main terminal of the semiconductor module 1 in which an inverter circuit is formed. The semiconductor module 1 has, for example, a half-bridge inverter circuit as shown in FIG. 6 formed therein. The half-bridge inverter circuit includes two switching elements 321 connected in series and a diode element 322 connected in anti-parallel to each of the switching elements 321. The switching elements 321 may be, for example, an insulated gate bipolar transistor (IGBT), a power metal oxide semiconductor field effect transistor (MOSFET), a bipolar junction transistor (BJT), or the like. The diode element 322 may be, for example, a free wheeling diode (FWD), a Schottky barrier diode (SBD), a junction barrier Schottky diode (JBS), a merged PN Schottky diode (MPS), a PN diode, or the like. When the switching element 321 is an IGBT element, the collector of one of the two switching elements 321A and 321C connected in series is connected to the first lead 5A, and the emitter of the other switching element 321C is connected to the second lead 5B. The emitter of the switching element 321A and the collector of the switching element 321C are connected to the third lead 5C. The gate of the switching element 321 is connected to a control terminal (not shown). The emitter of the switching element 321 may be connected to a control terminal other than the lead 5 (for example, a terminal connected to a circuit that generates a control signal to be applied to the gate, which may be called an auxiliary emitter terminal, emitter sense terminal, etc.). When the switching element 321 is a power MOSFET, the drain of one switching element 321A is connected to the first lead 5A, and the source of the other switching element 321C is connected to the second lead 5B. The source of the switching element 321A and the drain of the switching element 321C are connected to a third lead 5C.When the switching element 321 is a power MOSFET, its source may also be connected to a control terminal other than the lead 5 (for example, a terminal connected to a circuit that generates a control signal to be applied to the gate, which may be called an auxiliary source terminal or the like). The switching element 321 and the diode element 322 described above may be separate semiconductor elements 320, or may be a single semiconductor element 320 in which both elements are formed. The switching element 321 shown as a single element in FIG. 6 may be a plurality of switching elements formed in multiple semiconductor elements 320 and connected in parallel, with the diode element 322 connected in anti-parallel to each of the multiple switching elements. The switching element 321 is not limited to being made of silicon (Si), but may also be made of a wide bandgap semiconductor material such as silicon carbide (SiC) or gallium nitride (GaN).

[0021] External terminal portion 501 of lead 5 extends in a direction along the upper surface of wiring board 300, and has a through hole 510 formed therein with an opening in the plate thickness direction. External terminal portion 501 of first lead 5A is arranged parallel to upper surface 421 of first nut groove 420A so that through hole 510 overlaps with the screw hole of nut 7 accommodated in the nut accommodating portion in a plan view of upper surface 421 of first nut groove 420A. External terminal portion 501 of second lead 5B is arranged parallel to upper surface 421 of second nut groove 420B so that through hole 510 overlaps with the screw hole of nut 7 accommodated in the nut accommodating portion in a plan view of upper surface 421 of second nut groove 420B. The first lead 5A and the second lead 5B are integrally supported by an insulating support member 8, and by fitting the insulating support member 8 between the first nut groove 420A and the second nut groove 420B, the positional relationship between the external terminal portion 501 of each lead 5 and the upper surface 421 of the nut groove 420 is maintained.

[0022] The external terminal portion 501 of the third lead 5C is arranged parallel to the upper surface 421 of the third nut groove 420C so that the through hole 510 overlaps with the screw hole of the nut 7 accommodated in the nut accommodating portion 422 in a plan view of the upper surface 421 of the third nut groove 420C. The third lead 5C is bent at the boundary between the external terminal portion 501 and the first intermediate portion 502 so that the first intermediate portion 502 connected to the external terminal portion 501 is arranged parallel to the side surface 423 connected to the upper surface 421 of the third nut groove 420C. The first intermediate portion 502 of the third lead 5C passes between the third nut groove 420C and the lid portion 440.

[0023] The lead 5 has, between the bonded portion 500 and the first intermediate portion 502, a second intermediate portion 503 connected to the first intermediate portion 502, and a rising portion 504 connecting the second intermediate portion 503 and the bonded portion 500. The third lead 5C has an arm portion 508 at the second intermediate portion 503. The arm portion 508 extends from the second intermediate portion 503 in a direction opposite to the extension direction of the bonded portion 500 in an XY-plane view, and is arranged so that the external terminal portion 501 is arranged parallel to the upper surface 421 of the third nut groove 420C when the upper surface of the arm portion 508 abuts against the lower surface of the beam portion 401 of the case 4. Furthermore, the first intermediate portion 502 of the third lead 5C has a protrusion portion 509 protruding toward the inner peripheral wall surface of the frame body portion 400 located at the end in a direction parallel to the side surface 423 of the third nut groove 420C. The protrusion portion 509 of the third lead 5C is arranged so that when its upper surface abuts against the lower surface of the protrusion portion 402 of the frame body portion 400 of the case 4, the external terminal portion 501 is positioned parallel to the upper surface 421 of the third nut groove 420C.

[0024] 7 is a flow diagram illustrating a manufacturing process of the semiconductor module of the first embodiment. The manufacturing process of the semiconductor module 1 of the present embodiment includes, for example, a first step (S1) of arranging the circuit component 3 and the frame body portion 400 of the case 4 on the upper surface of the heat dissipation base 2 shown in FIG. 7; a second step (S2) of arranging the nut groove 420, which accommodates the nut 7, and the lead 5 in the nut accommodating portion 422; a third step (S3) of joining the joining portion 500 of the lead 5 to the conductive component of the circuit component 3 (the conductor pattern 302 of the wiring board 300); and a fourth step (S4) of arranging the lid portion 440 on the upper surface of the frame body portion 400. In the first step, for example, the wiring board 300 is arranged on the upper surface of the heat dissipation base 2 via a bonding material such as solder, and the semiconductor element 320 is further arranged on the upper surface of the wiring board 300 via the bonding material such as solder. After that, the bonding material is heated and melted, and the frame body portion 400 of the case is bonded to the upper surface of the heat dissipation base 2 with an adhesive. In the second step, for example, the lead 5 is arranged so that the bonded portion 500 is located at a predetermined position on the upper surface of the circuit component 3, and the nut groove 420 is attached to the upper surface of the frame body portion 400 with an adhesive or by press-fitting. In the third step, for example, the bonded portion 500 of the lead 5 is joined to the conductor pattern 302 of the wiring board 300 by ultrasonic bonding. In the fourth step, for example, the lid portion 440 is attached to the upper surface of the frame body portion 400 by press-fitting so as to close the opening at the upper end of the frame body portion 400 that was reserved for ultrasonic bonding in the third step.

[0025] However, when ultrasonic bonding is performed in the third step, the external terminal portion 501 of the lead 5 may rise from the upper surface 421 of the nut groove 420, which may result in a decrease (deterioration) in parallelism. For example, the third lead 5C has the external terminal portion 501 and the first intermediate portion 502, which are located far from the bonded portion 500, spaced apart from the third nut groove 420C, and the first intermediate portion 502 is also spaced apart from the lid portion 440, so that a decrease in parallelism due to ultrasonic bonding is likely to occur.

[0026] 8 is a diagram illustrating the lifting of the external terminal portion of the lead. Third lead 5C is formed so that, when the lower surface (bonding surface) of bonded portion 500 is brought into contact with conductive pattern 302 of wiring board 300, external terminal portion 501 is positioned parallel to upper surface 421 of third nut groove 420C at a predetermined distance G from upper surface 421. However, when bonded portion 500 is bonded to conductive pattern 302 by ultrasonic bonding, third lead 5C deforms in a direction that increases rise angle θ of rising portion 504. The rise angle θ may be the bending angle of rising portion 504, where angle θ is 0 degrees when rising portion 504 is parallel to bonded portion 500.

[0027] If the frame portion 400 of the case 4 does not have the beam portion 401 and the protrusion portion 402 described above, when the rise angle θ of the rising portion 504 increases due to ultrasonic bonding, the third lead 5C rotates around the boundary between the bonded portion 500 and the rising portion 504 as a fulcrum in a direction increasing the distance G between the external terminal portion 501 and the upper surface 421 of the third nut groove 420C, as illustrated in FIG. 2 and FIG. 11. Furthermore, as illustrated in FIGS. 2 and 11, the gap between the side surface 423 of the third nut groove 420C and the side surface 441 of the lid portion 440, through which the first intermediate portion 502 of the third lead 5C passes, is larger than the dimension corresponding to the plate thickness of the first intermediate portion 502 due to a clearance for improving the assembly workability of the semiconductor module 1. Therefore, when the rise angle θ of the rising portion 504 increases due to ultrasonic bonding, the external terminal portion 501 becomes tilted and less parallel with respect to the upper surface 421 of the third nut groove 420C. Therefore, for example, problems such as poor workability may arise when inserting the shaft of a bolt into the through hole 510 of the external terminal portion 501 and screwing it into the nut 7 (see Figure 2) to connect a component such as a cable terminal to the external terminal portion 501 of the third lead 5C.

[0028] In the semiconductor device of Patent Document 1, in a plan view, the extension direction of the main surface of the main terminal from the side portion differs from the extension direction of the tip from the fixing portion. Therefore, when the tip of the main terminal is joined to the electronic circuit of the board by ultrasonic bonding, the main surface tilts in a direction that increases the angle of the extension direction of the boundary between the main surface and the side portion relative to the in-plane direction of the front surface of the insertion portion facing the main surface. Furthermore, in the semiconductor device of Patent Document 2, the universal guide for fixing the main electrode to the case prevents left-right, front-back, and up-down movement of the main electrode. In the semiconductor device of Patent Document 2, one end of the main electrode 24 is joined to the wiring on the insulating substrate 20 using a joining material such as solder. However, when joined by ultrasonic bonding as described above, the main electrode may move in a direction other than left-right, front-back, and up-down movement, which may result in a phenomenon similar to the lifting of the external terminal described above with reference to FIG. 8.

[0029] In contrast, as described above, frame body 400 of case 4 according to the present embodiment is provided with beam 401 that abuts against the upper surface of arm 508 provided in second intermediate portion 503 of third lead 5C, and protrusion 402 that abuts against the upper surface of protrusion 509 provided in first intermediate portion 502. Therefore, when third lead 5C is ultrasonically bonded in the third step (S3) illustrated in Fig. 7, beam 401 and protrusion 402 provided on frame body 400 of case 4 prevent upward displacement of arm 508 and first intermediate portion 502 of third lead 5C (direction away from the upper surface of conductor pattern 302 of wiring board 300 to which bonded portion 500 is bonded). As a result, deformation of the third lead 5C that increases the rising angle θ of the rising portion 504 does not occur, and a decrease in the parallelism between the external terminal portion 501 of the third lead 5C and the upper surface 421 of the third nut groove 420C is prevented.

[0030] Note that the configuration for suppressing deformation that increases the rising angle θ of rising portion 504 of third lead 5C is not limited to the above-described combination. Frame body portion 400 of case 4 may be provided with only one of beam portion 401 and protrusion portion 402 (for example, only beam portion 401). Furthermore, beam portion 401 and protrusion portion 402 described above are merely examples of abutting portions that abut against third lead 5C so as to prevent an increase in the angle of external terminal portion 501 of third lead 5C in the extension direction relative to wiring board 300 due to rotation of intermediate portions 502, 503 and external terminal portion 501 of third lead 5C around the boundary between portion to be joined 500 and rising portion 504 as a fulcrum. That is, instead of beam portion 401, a pair of protrusions protruding from the inner peripheral wall surface of case 4 may be provided. Alternatively, instead of beam portion 401, for example, a through-hole or recess into which arm portion 508 of third lead 5C is inserted may be provided in the inner peripheral wall surface of case 4 or a wall portion protruding from the inner peripheral wall surface. Third lead 5C is not limited to the shape exemplified in FIG. 3 and the like. Arm portion 508 and protrusion portion 509 of third lead 5C may have any shape that abuts against abutting portions of beam portion 401 or the like on frame portion 400 of case 4 so as to prevent an increase in the angle of the extension direction of external terminal portion 501 relative to wiring board 300 due to rotation of intermediate portions 502, 503 and external terminal portion 501 of third lead 5C. Arm portion 508 and protrusion portion 509 may be omitted, and a surface of second intermediate portion 503 facing upward (away from wiring board 300) may abut against abutting portions of beam portion 401 or the like on case 4. Furthermore, the third lead 5C may have a number of bonded portions 500 other than four, and may have a number of external terminal portions 501 other than three.

[0031] In the semiconductor module 1 according to this embodiment, for example, the first lead 5A and the second lead 5B may also be configured so that the rotation of the external terminal portion 501 due to ultrasonic bonding is prevented by the abutment portion of the case 4. Furthermore, in the semiconductor module 1 according to this embodiment, the nut groove 420 may be formed integrally with the frame portion 400.

[0032] [Second embodiment] Fig. 9 is a plan view of a semiconductor module according to the second embodiment. Fig. 10 is a partially enlarged plan view of an area D in Fig. 9. Fig. 11 is a cross-sectional view taken along line E-E' in Fig. 10. Fig. 9 illustrates a semiconductor module 1 from which a portion of the lid 440 is omitted, and Fig. 10 illustrates a semiconductor module 1 from which a portion of the third lead 5C is omitted.

[0033] 9 to 11 may be similar to the semiconductor module 1 described in the first embodiment, except for the following first and second differences. The first difference is that the arm portion 508 and the protrusion 509 of the third lead 5C and the beam portion 401 and the protrusion 402 of the frame body portion 400 of the case 4 are not provided. The second difference is that the protrusion 424 and the protrusion 442 are provided on the upper surface 421 of the third nut groove 420C and on the side surface 441 of the lid portion 440 facing the first intermediate portion 502 of the third lead 5C, respectively.

[0034] A plurality of protrusions 424 of the third nut groove 420C (four in FIGS. 9 and 10) are provided in a region of the upper surface 421 that overlaps with the external terminal portion 501 of the third lead 5C in a plan view. The height H1 of the protrusions 424 of the third nut groove 420C and the height H2 of the protrusions 442 of the lid portion 440 are set so that the external terminal portion 501 of the third lead 5C extends parallel to the upper surface 421 at a position spaced a distance G (see FIG. 8) equivalent to the height H1 from the upper surface 421 of the third nut groove 420C. The height H1 of the protrusions 424 and the height H2 of the protrusions 442 of the lid portion 440 are not limited to any particular height. The height H2 of the protrusion 442 can be set based on, for example, the clearance between the side surface 441 of the lid portion 440 and the first intermediate portion 502 of the third lead 5C, and the clearance H3 between the side surface 423 of the third nut groove 420C and the first intermediate portion 502 of the third lead 5C. The protrusions 424, 442 are not limited to a particular shape, but by making them into a shape such as a spherical shape that reduces the contact area with the third lead 5C, for example, it is possible to prevent a decrease in workability when the lid portion 440 is press-fitted between the second nut groove 420B (see FIG. 9) and the first intermediate portion 502 of the third lead 5C and placed on the upper surface of the frame body 400.

[0035] Fig. 12 is a flow diagram illustrating a manufacturing process of the semiconductor module of the second embodiment. Fig. 13 is a diagram illustrating the effects of the configuration of the semiconductor module of the second embodiment. The manufacturing process of the semiconductor module 1 of this embodiment may include, for example, a first step (S11) of arranging the circuit component 3 and the frame body portion 400 of the case 4 on the upper surface of the heat dissipation base 2 shown in Fig. 12 , a second step (S12) of arranging the nut groove 420, which accommodates the nut 7, and the lead 5 in the nut accommodating portion 422, a third step (S13) of joining the to-be-joined portion 500 of the lead 5 to the conductive component of the circuit component 3 (the conductor pattern 302 of the wiring board 300), and a fourth step (S14) of arranging the lid portion 440 on the upper surface of the frame body portion 400. The first step (S11), second step (S12), third step (S13), and fourth step (S14) illustrated in FIG. 12 correspond to the first step (S1), second step (S2), third step (S3), and fourth step (S4) described above with reference to FIG. 7 in the first embodiment, respectively.

[0036] The frame body 400 used in the semiconductor module 1 of this embodiment does not have a portion, such as a beam 401, for preventing rotation of the intermediate portions 502 and 503 and the external terminal portion 501 of the third lead 5C during ultrasonic bonding. Therefore, when the bonded portion 500 of the third lead 5C is bonded to the conductive pattern 302 of the wiring board 300 by ultrasonic bonding in the third step, the external terminal portion 501 of the third lead 5C is separated from the protrusion 424 arranged on the upper surface 421 of the third nut groove 420 and raised, as shown by the solid line in FIG. 13 . At this time, the first intermediate portion 502 of the third lead 5C is displaced in a direction increasing its distance from the side surface 423 of the third nut groove 420C. However, when the lid portion 440 is placed on the upper surface of the frame body 400 in the subsequent fourth step, the protrusion 442 provided on the side surface 441 of the lid portion 440 abuts against the first intermediate portion 502 of the third lead 5C, displacing the first intermediate portion 502 in a direction approaching the side surface 423 of the third nut groove 420 (the position indicated by the two-dot chain line in FIG. 13 ). At this time, the third lead 5C rotates in a direction in which the rising angle θ decreases, with the boundary between the bonded portion 500 and the rising portion 504 as a fulcrum, so that the external terminal portion 501 is displaced in a direction approaching the upper surface 421 of the third nut groove 420C. Therefore, after the lid portion 440 is placed on the upper surface of the frame body 400, the external terminal portion 501 abuts against the protrusion 424 provided on the upper surface 421 of the third nut groove 420C and is supported in a state parallel to the upper surface 421, as illustrated in FIG. 11 .

[0037] As described above, in the semiconductor module 1 of the present embodiment, the protrusion 442 of the lid portion 440 corrects the third lead 5C deformed by ultrasonic bonding in a direction returning it to its pre-bonding (pre-deformation) shape. That is, in the semiconductor module 1 of the present embodiment, the protrusion 442 provided on the side surface 441 of the lid portion 440 prevents an increase in the angle of the extension direction of the external terminal portion 501 of the third lead 5C relative to the wiring board 300 due to rotation of the external terminal portion 501. As a result, in the semiconductor module 1 of the present embodiment as well, it is possible to prevent a decrease in the parallelism between the external terminal portion 501 of the third lead 5C and the upper surface 421 of the third nut groove 420C. Furthermore, even if, for example, the distance from the side 441 of the lid portion 440 to the side 423 of the third nut groove 420C becomes shorter due to tolerances or the like, and the rise angle θ (see Figure 8) of the rise portion 504 becomes smaller when the lid portion 440 is placed on the upper surface of the frame body portion 400 than the angle before joining, the protrusion portion 424 placed on the upper surface 421 of the third nut groove 420C maintains the distance between the external terminal portion 501 of the third lead 5C and the upper surface 421 of the third nut groove 420 at the height H1 of the protrusion portion 424, thereby suppressing a decrease in parallelism. Furthermore, since it is possible to prevent a decrease in the parallelism between the external terminal portion 501 of the third lead 5C and the upper surface 421 of the third nut glove 420 without providing a protrusion on the side surface 423 of the third nut glove 420C, it is also possible to prevent, for example, the third nut glove 420C from coming off the upper surface of the frame body portion 400 due to a pressure load being applied to the side surface 423 of the third nut glove 420C.

[0038] The protrusion 424 of the third nut groove 420C can be formed integrally with the third nut groove 420C, for example, by providing a recess corresponding to the protrusion 424 in a mold used to form the third nut groove 420 by transfer molding. The protrusion 442 of the lid portion 440 can also be formed integrally with the lid portion 440 by providing a recess corresponding to the protrusion 442 in a mold used to form the lid portion 440 by transfer molding. The number and arrangement of the protrusions 424 and 442 are not limited to a specific number and arrangement. For example, as shown in FIG. 11 , if a wall portion protruding upward is provided at the end of the top surface of the lid portion 440 on the side surface 441 side, the protrusion 442 can be positioned in a region of the side surface 441 of the lid portion 440 that is thicker from the side surface 441 below the bottom end of the wall portion, thereby suppressing deformation of the lid portion 440 (wall portion) due to the reaction force from the third lead 5C to be corrected.

[0039] In the semiconductor module 1 according to this embodiment, for example, the first lead 5A and the second lead 5B may also be configured to correct the external terminal portion 501 that has rotated due to ultrasonic bonding by the protrusions on the upper surface 421 of the corresponding nut groove 420 and the protrusions on the lid portion 440. Furthermore, in the semiconductor module 1 according to this embodiment, the nut groove 420 may be formed integrally with the frame portion 400.

[0040] The semiconductor module 1 of the above-described embodiment is not limited to a specific application, but a semiconductor module 1 equipped with a cooler 6 is particularly suitable for use in high-temperature environments. For example, the semiconductor module 1 of the above-described embodiment may be applied to a power conversion device such as an inverter device for an in-vehicle motor. The vehicle to which the semiconductor module 1 is applied is not limited to four-wheeled vehicles, but may also be a two-wheeled vehicle, a railway vehicle, or the like. The semiconductor module 1 may also be applied to an industrial power conversion device, such as an inverter device that drives a motor for an elevator, an escalator, or a building air conditioning system. The circuit formed in the semiconductor module 1 is not limited to the half-bridge inverter circuit exemplified in FIG. 6. The circuit formed in the semiconductor module 1 is not limited to an inverter circuit and may be another circuit, or may include an inverter circuit and another circuit.

[0041] The features of the above-described embodiment will be summarized below. The semiconductor module according to the above-described embodiment comprises a circuit component including a wiring board and a semiconductor element mounted on the wiring board, leads joined to the conductor pattern of the circuit component, and a case having a recess on its front surface into which a nut is housed, the case comprising a frame body portion surrounding the wiring board and a lid portion closing an opening of the frame body portion, the leads having external terminal portions extending along the wiring board, a bonded portion joined to the conductor pattern, and an intermediate portion connecting the bonded portion and the external terminal portion, and the case is provided with an abutment portion that abuts against the lead so as to prevent an increase in the angle of the extension direction of the external terminal portion of the lead relative to the wiring board due to rotation of the intermediate portion of the lead and the external terminal portion around the boundary between the bonded portion and the intermediate portion as a fulcrum.

[0042] In the semiconductor module of the above embodiment, the case further includes a nut glove that is arranged at the opening end of the frame body portion and has a recess in which the nut is accommodated, and the abutment portion of the case prevents an increase in the angle of the extension direction of the external terminal portion of the lead relative to the front surface of the nut glove due to rotation of the external terminal portion, and the abutment portion of the case is provided on the frame body portion and abuts against the back surface of the surface facing the wiring board at the intermediate portion of the lead, preventing rotation of the intermediate portion of the lead in a direction away from the wiring board.

[0043] In the semiconductor module of the above embodiment, the lid portion is positioned a predetermined distance away from the nut groove, the abutment portion of the case is a protrusion that protrudes from the inner wall surface of the frame body portion, and an arm portion is provided at the intermediate portion of the lead, the height from the wiring board being lower than the height of the protrusion, and the arm portion abuts against the protrusion.

[0044] In the semiconductor module of the above embodiment, the case further includes a nut glove that is arranged at the opening end of the frame body portion and has a recess in which the nut is accommodated, the abutment portion of the case prevents an increase in the angle of the extension direction of the external terminal portion of the lead relative to the front surface of the nut glove due to rotation of the external terminal portion, the lid portion is arranged a predetermined distance away from the nut glove, and the abutment portion of the case includes a first protrusion that is arranged on the front surface of the nut glove and a second protrusion that is arranged on a side of the lid portion opposite the intermediate portion of the lead, and the external terminal portion of the lead abuts against the first protrusion, and the intermediate portion of the lead abuts against the second protrusion.

[0045] In the semiconductor module according to the above embodiment, the first protrusion and the second protrusion have spherical tip portions that come into contact with the leads.

[0046] In the semiconductor module according to the above embodiment, an inverter circuit is formed using the circuit components.

[0047] The semiconductor module according to the above embodiment further includes a heat dissipation base on a first surface of which the circuit components and the case are arranged.

[0048] 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]

[0049] As described above, the present invention has the effect of preventing a decrease in the parallelism between the external terminal portions of the leads of a semiconductor module and the surface (front surface) of the case, and of facilitating the attachment of components such as cable terminals to the external terminal portions of the leads, and is particularly useful for industrial or vehicular semiconductor modules used as power conversion devices. [Explanation of symbols]

[0050] REFERENCE SIGNS LIST 1...Semiconductor module, 2...Heat dissipation base, 3, 3A to 3D...Circuit component, 300...Wiring board, 302...Conductive pattern, 320, 320A, 320C...Semiconductor element, 4...Case, 400...Frame body portion, 401...Beam portion, 402...Protrusion portion, 420, 420A to 420C...Nut groove, 440...Cover portion, 424, 442...Protrusion portion, 5, 5A to 5C...Lead, 500...To be joined portion, 501...External terminal portion, 502...First intermediate portion, 504...Rising portion, 508...Arm portion, 509...Protrusion portion, 6...Cooler, 7...Nut

Claims

1. a circuit component including a wiring board and a semiconductor element mounted on the wiring board; a lead joined to the conductor pattern of the circuit component; a case having a recess provided on the front surface thereof and a nut housed in the recess; the case includes a frame portion that surrounds the wiring board and a lid portion that closes an opening of the frame portion, the lead has an external terminal portion extending along the wiring board, a joined portion joined to the conductor pattern, and an intermediate portion connecting the joined portion and the external terminal portion, The case is provided with an abutment portion that abuts against the lead so as to prevent an increase in the angle of the extension direction of the external terminal portion of the lead relative to the wiring board due to rotation of the intermediate portion of the lead and the external terminal portion around the boundary between the joined portion and the intermediate portion as a fulcrum. Semiconductor module.

2. The case further includes a nut groove disposed at an open end of the frame body portion and having a recess in which the nut is accommodated, the abutment portion of the case prevents an increase in the angle of the extension direction of the external terminal portion of the lead relative to the front surface of the nut groove due to rotation of the external terminal portion, 2. The semiconductor module according to claim 1, wherein the abutment portion of the case is provided on the frame body portion and abuts against the backside of the surface of the intermediate portion of the lead facing the wiring board, thereby preventing the intermediate portion of the lead from rotating in a direction away from the wiring board.

3. The lid portion is disposed at a predetermined distance from the nut groove, the abutment portion of the case is a protrusion that protrudes from an inner peripheral wall surface of the frame body portion, 3. The semiconductor module according to claim 2, wherein the intermediate portion of the lead is provided with an arm portion whose height from the wiring board is lower than that of the protruding portion and which abuts against the protruding portion.

4. The case further includes a nut groove disposed at an open end of the frame body portion and having a recess in which the nut is accommodated, the abutment portion of the case prevents an increase in the angle of the extension direction of the external terminal portion of the lead relative to the front surface of the nut groove due to rotation of the external terminal portion, The lid portion is disposed at a predetermined distance from the nut groove, the abutment portion of the case includes a first protrusion disposed on the front surface of the nut groove and a second protrusion disposed on a side surface of the lid portion facing the intermediate portion of the lead, the external terminal portion of the lead abuts against the first protrusion, and the intermediate portion of the lead abuts against the second protrusion; The semiconductor module according to claim 1 .

5. 5. The semiconductor module according to claim 4, wherein the first protrusion and the second protrusion have spherical tip portions that come into contact with the leads.

6. 2. The semiconductor module according to claim 1, wherein the circuit components form an inverter circuit.

7. 7. The semiconductor module according to claim 1, further comprising a heat dissipation base on a first surface of which the circuit components and the case are arranged.

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