Semiconductor module and manufacturing method thereof

Abstract

To reduce the possibility of displacement of connection terminals in a semiconductor module.SOLUTION: A semiconductor module 100 includes a mounting substrate 30, a semiconductor chip 40 mounted on the mounting substrate 30, a cylindrical supporting conductor 61 mounted on the mounting substrate 30, an accommodating portion 20 that accommodates the mounting substrate 30, the semiconductor chip 40, and the supporting conductor 61, a connecting terminal 62 that includes a first end pressed into the supporting conductor 61 and a second end protruding from the accommodating portion 20 and is electrically connected to the semiconductor chip 40, and a conductive joint that is located between the inner wall surface of the supporting conductor 61 and the outer wall surface of the connecting terminal 62 and joins the supporting conductor 61 to the connecting terminal 62.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a semiconductor module and a manufacturing method thereof. [Background technology]

[0002] Semiconductor modules have been proposed in which connection terminals for electrically connecting a semiconductor chip to an external device protrude from an exterior surface. For example, Patent Document 1 discloses a power semiconductor device that includes a cylindrical electrode fixed to a circuit pattern on which a semiconductor element is mounted, and a connection terminal inserted into the cylindrical electrode. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2011-165836 A [Patent Document 2] JP 2013-125803 A [Patent Document 3] JP 2010-027813 A [Patent Document 4] JP 2010-129670 A Summary of the Invention [Problem to be solved by the invention]

[0004] An external device such as a wiring board is joined to the connection terminal. Therefore, an external force from the external device acts on the connection terminal, and as a result, the connection terminal may be displaced (and may fall off) relative to the cylindrical electrode. In consideration of the above circumstances, one aspect of the present disclosure aims to reduce the possibility of the connection terminal being displaced. [Means for solving the problem]

[0005] In order to solve the above problems, a semiconductor module according to one embodiment of the present disclosure includes a mounting substrate, a semiconductor chip mounted on the mounting substrate, a cylindrical supporting conductor mounted on the mounting substrate, a housing portion that houses the mounting substrate, the semiconductor chip, and the supporting conductor, a connection terminal that includes a first end pressed into the supporting conductor and a second end protruding from the housing portion, and is electrically connected to the semiconductor chip, and a first conductive joint portion that is located between an inner wall surface of the supporting conductor and an outer wall surface of the connecting terminal, and joins the supporting conductor and the connecting terminal.

[0006] A manufacturing method for a semiconductor module according to one embodiment of the present disclosure includes a mounting process for placing a semiconductor chip and a cylindrical supporting conductor on a mounting substrate, and a joining process for joining the supporting conductor and the connecting terminal by a first joint between an inner wall surface of the supporting conductor and an outer wall surface of the connecting terminal, with a first end of the connecting terminal pressed into the supporting conductor and a second end of the connecting terminal protruding from a housing portion that houses the mounting substrate, the semiconductor chip, and the supporting conductor. [Brief description of the drawings]

[0007] [Figure 1] 1 is a cross-sectional view of a semiconductor module according to an embodiment. [Diagram 2] FIG. [Diagram 3] FIG. [Figure 4] FIG. [Diagram 5] 1 is a cross-sectional view of a semiconductor module in use; [Figure 6] 1 is a flowchart showing a manufacturing process of a semiconductor module. [Figure 7] FIG. [Figure 8] FIG. 11 is a cross-sectional view of a connection terminal in a modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] The embodiments for carrying out the present disclosure will be described with reference to the drawings. Note that in each drawing, the dimensions and scale of each element may differ from those of the actual product. The embodiment described below is an exemplary embodiment assumed when carrying out the present disclosure. Therefore, the scope of the present disclosure is not limited to the embodiment exemplified below.

[0009] A: Structure of semiconductor module 100 FIG. 1 is a cross-sectional view of a semiconductor module 100 according to an embodiment of the present disclosure. In the following description, the Z axis is assumed. One direction along the Z axis is referred to as the Z1 direction, and the opposite direction to the Z1 direction is referred to as the Z2 direction. In actual use, the semiconductor module 100 is installed in any direction, but for convenience in the following description, the Z1 direction is assumed to be downward, and the Z2 direction is assumed to be upward. Therefore, the surface of any element of the semiconductor module 100 facing the Z1 direction may be referred to as the "lower surface", and the surface of the element facing the Z2 direction may be referred to as the "upper surface". In addition, observing an object with a line of sight along the Z axis is referred to as "planar view" below.

[0010] The semiconductor module 100 of this embodiment is a power semiconductor device constituting a power conversion device such as an inverter circuit. As illustrated in Fig. 1, the semiconductor module 100 includes a semiconductor unit 10 and a housing section 20. The housing section 20 houses the semiconductor unit 10.

[0011] The semiconductor unit 10 includes a mounting substrate 30, a semiconductor chip 40, a plurality of wires 50, and a plurality of external terminals 60. Although one semiconductor chip 40 is illustrated in Fig. 1 for the sake of convenience, the semiconductor module 100 actually includes a plurality of semiconductor chips 40.

[0012] The mounting substrate 30 is a wiring substrate on which the semiconductor chip 40 is mounted. For example, a substrate such as a direct copper bonding (DCB) substrate, an active metal brazing (AMB) substrate, or an insulated metal substrate (IMS) substrate is used as the mounting substrate 30.

[0013] The mounting board 30 is formed by laminating an insulating substrate 31, a metal layer 32, and a plurality of conductive patterns 33. The insulating substrate 31 is a rectangular plate-like member made of an insulating material. The insulating substrate 31 is made of a ceramic material such as aluminum oxide, aluminum nitride, or silicon nitride, or a resin material such as epoxy resin.

[0014] The metal layer 32 is a thin plate-like conductor bonded to the lower surface of the insulating substrate 31. The metal layer 32 is formed of a metal material with high thermal conductivity, such as copper or aluminum, and transfers heat generated in the semiconductor chip 40 to the heat dissipation mechanism 200. The heat dissipation mechanism 200 is a structure bonded to the metal layer 32, and is formed of a conductive material, such as aluminum or copper.

[0015] Each of the plurality of conductive patterns 33 is a thin plate-like conductor disposed on the upper surface of the insulating substrate 31. Each conductive pattern 33 is formed from a low-resistance conductive material such as copper or a copper alloy.

[0016] The semiconductor chip 40 is a power semiconductor element mounted on the mounting substrate 30, and is used as a switching element that switches between conducting and blocking a current. The semiconductor chip 40 of this embodiment is, for example, an RC-IGBT (Reverse Conducting IGBT) including an IGBT (Insulated Gate Bipolar Transistor) and an FWD (Free Wheeling Diode). The semiconductor chip 40 is joined to the conductive pattern 33 by a joint 34a. The joint 34a is formed of a conductive joining material such as solder or a sintered material.

[0017] The semiconductor chip 40 includes a first electrode 41, a second electrode 42, and a control electrode (not shown). The first electrode 41 and the second electrode 42 are electrodes to which a current to be controlled is input or output. The first electrode 41 is a collector electrode that constitutes the lower surface of the semiconductor chip 40, and also functions as a cathode electrode of the FWD. The first electrode 41 of the semiconductor chip 40 is joined to the conductive pattern 33 by a joint 34a. The second electrode 42 is an emitter electrode that constitutes the upper surface of the semiconductor chip 40, and also functions as an anode electrode of the FWD. The control electrode is a gate electrode to which a control voltage for controlling the on / off of the semiconductor chip 40 is applied, and constitutes the upper surface of the semiconductor chip 40 together with the second electrode 42.

[0018] Each of the multiple wires 50 is a linear conductor that electrically connects multiple elements of the semiconductor unit 10. The multiple wires 50 include wires 50 that connect the conductive patterns 33 to each other and wires 50 that connect the conductive patterns 33 to the semiconductor unit 10.

[0019] Each of the multiple external terminals 60 is an external terminal 60 for electrically connecting the semiconductor unit 10 to an external device. Each external terminal 60 is joined to the conductive pattern 33 by a joint 34b. The joint 34b is formed of a conductive joining material such as solder or a sintered material. The joint 34b is an example of a "second joint".

[0020] Fig. 2 is an exploded perspective view illustrating the configuration of the external terminal 60. Fig. 3 is a cross-sectional view of the external terminal 60. Fig. 3 illustrates a cross section of the external terminal 60 taken along the Z-axis. As illustrated in Figs. 1 to 3, the external terminal 60 includes a supporting conductor 61, a connection terminal 62, and a joint portion 63.

[0021] The supporting conductor 61 is a cylindrical conductor disposed on the mounting substrate 30. Specifically, as illustrated in Fig. 2 and Fig. 3, the supporting conductor 61 is a structure in which a tubular portion 610, a first flange portion 611, and a second flange portion 612 are integrally formed. The supporting conductor 61 is formed of a low-resistance conductive material such as copper or a copper alloy. The supporting conductor 61 may be plated with, for example, tin or nickel.

[0022] The cylindrical portion 610 is a cylindrical portion whose central axis is along the Z axis. The inner diameter D of the cylindrical portion 610 is constant over the entire range in the axial direction. The cylindrical portion 610 includes a lower end Ea and an upper end Eb located on opposite sides of each other. The lower end Ea is an open end located in the Z1 direction. The upper end Eb is an open end located in the Z2 direction.

[0023] The first flange 611 is an annular flange protruding radially outward from the lower end Ea of the cylindrical portion 610. As illustrated in Fig. 3, the first flange 611 of the supporting conductor 61 is joined to the conductive pattern 33 by a joint 34b. The second flange 612 is an annular flange protruding radially outward from the upper end Eb of the cylindrical portion 610. One or both of the first flange 611 and the second flange 612 may be omitted.

[0024] The connection terminal 62 is an elongated conductor. Specifically, the connection terminal 62 is a square prism-shaped structure with a square cross section. The connection terminal 62 is made of a low-resistance conductive material such as copper or a copper alloy. The connection terminal 62 may be plated with, for example, tin or nickel.

[0025] The connection terminal 62 includes a first end E1 and a second end E2 located opposite each other in the direction of the Z axis. The first end E1 is an end in the Z1 direction (i.e., a lower end). The first end E1 is inserted into the supporting conductor 61. The second end E2 is an end in the Z2 direction (i.e., an upper end). The overall length L of the connection terminal 62 exceeds the overall length H of the supporting conductor 61.

[0026] The connection terminal 62 is supported by the supporting conductor 61 by being inserted into the supporting conductor 61. As illustrated in Fig. 3, a first end E1 of the connection terminal 62 does not contact the conductive pattern 33. That is, when the connection terminal 62 is inserted into the supporting conductor 61, a gap is secured between the first end E1 and the conductive pattern 33. On the other hand, the second end E2 protrudes from an upper end Eb of the supporting conductor 61 in the Z2 direction.

[0027] Fig. 4 is a cross-sectional view of the external terminal 60. Specifically, a cross section perpendicular to the Z-axis passing through the cylindrical portion 610 of the external terminal 60 is shown in Fig. 4. As illustrated in Fig. 4, the inner diameter D of the cylindrical portion 610 of the supporting conductor 61 is slightly shorter than the diagonal length G of the connecting terminal 62. Therefore, a portion of the connecting terminal 62 located inside the supporting conductor 61 contacts an inner wall surface 614 of the supporting conductor 61.

[0028] That is, the four corners of the cross section of the connection terminal 62 press radially outward against the inner wall surface 614 of the supporting conductor 61. As illustrated in Fig. 4, the portions of the supporting conductor 61 pressed by the corners of the connection terminal 62 protrude radially outward.

[0029] As can be understood from the above description, the first end E1 of the connection terminal 62 is press-fitted into the supporting conductor 61. Therefore, the connection terminal 62 is electrically connected to the semiconductor chip 40 via the supporting conductor 61 and the conductive pattern 33. As illustrated in Fig. 4, a region of the outer wall surface 621 of the connection terminal 62 other than the corner portion faces the inner wall surface 614 of the supporting conductor 61 with a gap S therebetween.

[0030] The joint 63 is a conductor that joins the supporting conductor 61 and the connection terminal 62 to each other, and is formed by a conductive joint 63 such as solder or a sintered material. For example, the joint 63 is formed by an alloy material containing tin as the main component and bismuth, copper, nickel, or the like. The joint 63 is an example of a "first joint".

[0031] 2, the joint portion 63 covers a portion of the connection terminal 62, including the first end E1. The joint portion 63 is not formed on the remaining portion of the connection terminal 62, including the second end E2. In other words, the second portion 632 of the connection terminal 62 is exposed from the joint portion 63.

[0032] As illustrated in FIG. 3, the joint 63 includes a first portion 631 and a second portion 632. The first portion 631 is a portion located between the inner wall surface 614 of the supporting conductor 61 and the outer wall surface 621 of the connecting terminal 62. That is, as illustrated in FIG. 4, the first portion 631 is filled in the arc-shaped gap S between the inner wall surface 614 of the supporting conductor 61 and the outer wall surface 621 of the connecting terminal 62. Specifically, the bonding material covering the connecting terminal 62 melts and enters the gap S, and the bonding material in the gap S solidifies to form the joint 63. The first portion 631 also covers the end face of the first end E1.

[0033] On the other hand, the second portion 632 is a portion of the joint 63 that is located in the Z2 direction further than the upper end Eb of the supporting conductor 61. In other words, the second portion 632 is a portion of the joint 63 that is exposed from the supporting conductor 61.

[0034] 1 accommodates the semiconductor unit 10 described above. Specifically, the accommodation section 20 accommodates the mounting substrate 30, the semiconductor chip 40, the plurality of wires 50, and the supporting conductors 61 of the external terminals 60. The accommodation section 20 of this embodiment includes a housing 21, a sealing body 22, and a lid section 23.

[0035] The housing 21 is a rectangular frame-shaped structure that surrounds the semiconductor unit 10. The mounting board 30 is fixed to the housing 21 by, for example, an adhesive. The housing 21 is formed of various insulating resins, such as, for example, polyphenylene sulfide (PPS) resin, polybutylene terephthalate (PBT) resin, polybutylene succinate (PBS) resin, polyamide (PA) resin, or acrylonitrile-butadiene-styrene (ABS) resin.

[0036] The sealing body 22 is an insulating material filled in the internal space of the housing 21, and seals the semiconductor unit 10. That is, the sealing body 22 is filled in the internal space surrounded by the housing 21 with the mounting board 30 as the bottom surface.

[0037] The sealing body 22 is formed of a resin material softer than the housing 21. For example, the sealing body 22 is formed of silicone gel. However, the material of the sealing body 22 is not limited to the above examples. For example, the sealing body 22 may be formed of a resin material such as rubber (e.g., silicone rubber) that is softer than the housing 21. Furthermore, the sealing body 22 may contain various fillers such as silicon oxide or aluminum oxide.

[0038] The lid portion 23 is a flat member that closes the opening of the housing 21. Each connection terminal 62 passes through a through hole formed in the lid portion 23. Therefore, as illustrated in FIG. 1, the second end E2 of each connection terminal 62 protrudes from the storage portion 20. Specifically, the second end E2 protrudes in the Z2 direction from an exterior surface F of the storage portion 20 that faces the Z2 direction. The exterior surface F is a surface of the storage portion 20 that includes the top surface of the housing 21 and the upper surface of the lid portion 23. The lid portion 23 may be configured integrally with the housing 21.

[0039] Fig. 5 is a cross-sectional view showing a state in which the semiconductor module 100 is used. As illustrated in Fig. 5, in a state in which the semiconductor module 100 is used, a wiring board 70 is fixed to the semiconductor module 100. The wiring board 70 is a hard circuit board on which, for example, a drive circuit and a power supply circuit used to drive the semiconductor module 100 are mounted.

[0040] Specifically, the wiring board 70 is fixed to the semiconductor module 100 in a state facing the exterior surface F of the housing section 20. The wiring board 70 is fixed to the housing 21 by fasteners (not shown) such as screws or bolts. Each connection terminal 62 is inserted into a through hole 71 formed in the wiring board 70. The second end E2 is joined to the wiring board 70 by a conductive bonding material such as solder or a sintered material.

[0041] As described above, each connection terminal 62 is joined to the wiring board 70. Therefore, an external force in the Z2 direction may act on each connection terminal 62 from the wiring board 70. For example, in the process of replacing the wiring board 70, when the installed wiring board 70 is moved in the Z2 direction for removal, an external force in the Z2 direction also acts on the connection terminal 62. In this embodiment, since the supporting conductor 61 and the connection terminal 62 are joined by the joint 63, it is possible to suppress displacement (and thus detachment) of the connection terminal 62 due to the action of an external force from the wiring board 70, compared to a configuration in which the connection terminal 62 is simply inserted into the supporting conductor 61.

[0042] Next, the melting points (solidus temperature Ts, liquidus temperature Tl) of the bonding material used to form the bonding portion 63 will be described. The solidus temperature Ts of the bonding portion 63 is the temperature at which the solid-phase bonding material starts to melt as the temperature increases. The liquidus temperature Tl of the bonding portion 63 is the temperature at which the bonding material completely melts as the temperature increases. In other words, the liquidus temperature Tl is the temperature at which the liquid-phase bonding material starts to solidify as the temperature decreases, and the solidus temperature Ts is the temperature at which the bonding material completely solidifies as the temperature decreases. The liquidus temperature Tl is higher than the solidus temperature Ts (Tl>Ts).

[0043] First, the solid-phase temperature Ts of the joint 63 exceeds the maximum environmental temperature Tc in which the semiconductor module 100 is used (Ts>Tc). The maximum environmental temperature Tc is the highest temperature in the environment in which the semiconductor module 100 is used. For example, the maximum operating temperature in the specifications of the semiconductor module 100 is the maximum environmental temperature Tc. For example, the maximum case temperature in the specifications of the semiconductor module 100 may be set as the maximum environmental temperature Tc. The maximum case temperature is the maximum temperature of the housing 21 expected in normal use. As described above, according to the configuration of this embodiment, the solid-phase temperature Ts of the joint 63 exceeds the maximum environmental temperature Tc of the semiconductor module 100, so that the possibility of the joint 63 melting in the actual use environment of the semiconductor module 100 can be reduced.

[0044] Also, the liquid-phase temperature Tl of the joint 63 is lower than the maximum junction temperature Tjmax of the semiconductor chip 40 (Tl < Tjmax). The maximum junction temperature Tjmax is the maximum value of the temperature at which the semiconductor chip 40 operates properly.

[0045] Furthermore, the liquid-phase temperature Tl of the joint 63 is lower than the solid-phase temperatures Tref of the joints 34a and 34b (Tl < Tref). According to the above aspect, the liquid-phase temperature Tl of the joint 63 for joining the connection terminal 62 and the support conductor 61 is lower than the solid-phase temperatures Tref of the joints 34a and 34b. Therefore, the connection terminal 62 and the support conductor 61 can be joined by melting and solidifying the joint 63 while maintaining the joining of the semiconductor chip 40 and the mounting substrate 30 by the joint 34a and the joining of the mounting substrate 30 and the support conductor 61 by the joint 34b.

[0046] Note that in the process of melting the bonding material for joining each connection terminal 62 to the wiring substrate 70, the temperature of the joint 63 of the external terminal 60 may rise. However, at the stage where the wiring substrate 70 is installed, since the heat dissipation mechanism 200 is joined to the metal layer 32 of the mounting substrate 30, excessive temperature rise of the joint 63 is suppressed by heat dissipation from the heat dissipation mechanism 200. Therefore, the possibility that the joint 63 melts when the wiring substrate 70 is installed is low. Also, even if the joint 63 temporarily melts when the wiring substrate 70 is installed, the joint 63 re-solidifies by being cooled after the wiring substrate 70 is installed. Therefore, the joining of the support conductor 61 and the connection terminal 62 is maintained, and the melting of the joint 63 does not pose a particular problem.

[0047] B: Manufacturing Method of Semiconductor Module 100 The manufacturing method of the semiconductor module 100 illustrated above will be described. FIG. 6 is an explanatory diagram of the process of manufacturing the semiconductor module 100.

[0048] In a mounting process P1, the semiconductor chip 40 and the supporting conductor 61 are placed on the mounting substrate 30. Specifically, first, in a process P11, a paste-like bonding material is applied to the surface of the mounting substrate 30, and the semiconductor chip 40 and the supporting conductor 61 are placed on the bonding material. In a process P12 after the process P11, the bonding material is melted and solidified to form the bonding portion 34a and the bonding portion 34b. That is, the semiconductor chip 40 is bonded to the mounting substrate 30 by the bonding portion 34a, and the supporting conductor 61 is bonded to the mounting substrate 30 by the bonding portion 34b. In a wiring process P2 after the mounting process P1, a plurality of wires 50 are formed.

[0049] On the other hand, in a plating process P3, a bonding material C is provided on the connection terminal 62. For example, as illustrated in Fig. 7, the connection terminal 62 is immersed in a plating bath of the bonding material C stored in a storage container 80, and the bonding material C is provided on a portion of the connection terminal 62 including the first end E1.

[0050] The timing relationship between the mounting step P1 and the wiring step P2 and the plating step P3 is arbitrary. For example, the plating step P3 may be performed before or after the mounting step P1 and the wiring step P2, or may be performed in parallel with the mounting step P1 or the wiring step P2.

[0051] In a press-fitting step P4 after the wiring step P2 and the plating step P3, the connection terminals 62 are press-fitted into each supporting conductor 61. Specifically, the portions of the connection terminals 62 on which the bonding material C is provided (a portion including the first end E1) are press-fitted into the supporting conductors 61. Immediately after the press-fitting step P4, the bonding material C that will become the joints 63 is not melted. That is, the joints 63 that join the supporting conductors 61 and the connection terminals 62 are not yet formed.

[0052] In a housing step P5 after the press-fitting step P4, the semiconductor unit 10 is housed in the housing section 20. First, in a step P51 of the housing step P5, the mounting board 30 is fixed to the housing 21. For example, various adhesives are used to fix the mounting board 30. In a step P52 after the step P51, a resin material is formed in the space surrounded by the housing 21 with the mounting board 30 as the bottom surface. Specifically, a liquid resin material such as silicone gel is filled into the internal space of the housing 21, and the resin material is cured by heating to form the sealing body 22.

[0053] In step P53 after step P52, the opening of the housing 21 is closed by the lid portion 23. Each connection terminal 62 is inserted into a through hole of the lid portion 23. In the stage immediately after the accommodating step P5 described above, the bonding material C is placed on the portion of the connection terminal 62 that is inside the accommodating portion 20, and the portion of the connection terminal 62 that is outside the accommodating portion 20 is exposed from the bonding material C.

[0054] The steps (P1 to P5) exemplified above are the assembly steps of the semiconductor module 100. Immediately after the assembly step, the first end E1 of the connection terminal 62 is press-fitted into the supporting conductor 61, and the second end E2 of the connection terminal 62 protrudes from the housing portion 20 that houses the semiconductor unit 10. After the semiconductor module 100 is assembled as described above, an inspection step P6 of the semiconductor module 100 is performed before the product is shipped. The inspection step P6 is a step of evaluating the characteristics of the semiconductor chip 40 (pre-shipment inspection).

[0055] The inspection process P6 of this embodiment includes a dynamic characteristic test P61 and a static characteristic test P62. The dynamic characteristic test P61 is a test for evaluating the characteristics of each semiconductor chip 40 while dynamically changing the current supplied to the semiconductor chip 40. The static characteristic test P62 is a test for evaluating the characteristics of the semiconductor chip 40 when a predetermined direct current is supplied. In the dynamic characteristic test P61 and the static characteristic test P62, for example, the electrical characteristics, temperature characteristics, and insulation characteristics of the semiconductor chip 40 are tested.

[0056] In the inspection process P6, the semiconductor chips 40 are driven in a state in which the semiconductor module 100 is heated. Specifically, in the inspection process P6, each semiconductor chip 40 is driven in a state in which the semiconductor module 100 is heated to a temperature in the vicinity of the maximum junction temperature Tjmax, and it is evaluated whether each semiconductor chip 40 operates properly.

[0057] As described above, the liquidus temperature Tl of the bonding material C for forming the bonding portion 63 is lower than the maximum junction temperature Tjmax of the semiconductor chip 40. Therefore, the semiconductor module 100 is heated to a temperature close to the maximum junction temperature Tjmax in the inspection process P6, whereby the bonding material C melts, and the semiconductor module 100 is cooled during the inspection process P6, whereby the bonding material C solidifies. The bonding portion 63 is formed by melting and solidifying the bonding material C. Note that, as described above with reference to FIG. 4, the connection terminal 62 is in contact with the inner wall surface 614 of the supporting conductor 61, and therefore electrical continuity between the supporting conductor 61 and the connection terminal 62 is maintained even when the bonding material C is in a molten state in the inspection process P6.

[0058] That is, the inspection process P6 in this embodiment includes a bonding process Q in which a bonded portion 63 is formed by melting and solidifying the bonding material C. The bonding process Q is a process in which the supporting conductor 61 and the connecting terminal 62 are bonded to each other at a bonded portion 63 between the inner wall surface 614 of the supporting conductor 61 and the outer wall surface 621 of the connecting terminal 62. The bonding process Q in this embodiment is a process in which the bonding material C is melted and solidified by heating the semiconductor module 100 in the inspection process P6. That is, the bonding process Q is realized by heating the semiconductor module 100 in the inspection process P6. The manufacturing process of the semiconductor module 100 is as described above.

[0059] As described above, in this embodiment, the first end E1 on which the bonding material C that becomes the joint 63 is formed is press-fitted into the supporting conductor 61. Therefore, compared to a mode in which the bonding material C is provided after the first end E1 is press-fitted into the supporting conductor 61, for example, the bonding portion 63 can be easily provided between the inner wall surface 614 of the supporting conductor 61 and the outer wall surface 621 of the connecting terminal 62. However, the bonding material C may be injected between the supporting conductor 61 and the connecting terminal 62 after the first end E1 is press-fitted into the supporting conductor 61.

[0060] In a configuration in which the bonding material C is provided over the entire connecting terminal 62 including the first end E1 and the second end E2 (hereinafter referred to as the “comparative configuration”), the bonding material C located near the second end E2 may melt and then solidify, forming a localized protrusion (lump). If a protrusion is formed near the second end E2, for example, the insertion of the second end E2 into the through hole 71 of the wiring board 70 may be hindered.

[0061] In contrast to the comparative example, in this embodiment, the bonding material C is provided on the inside of the housing portion 20 of the connection terminal 62, and the outside of the housing portion 20 of the connection terminal 62 is exposed from the bonding material C. That is, the bonding portion 63 is formed on a part of the connection terminal 62 including the first end E1, and the second end E2 is exposed from the bonding portion 63. According to the above embodiment, it is possible to suppress the formation of a protrusion caused by melting of the bonding material C in the vicinity of the second end E2. Therefore, it is possible to easily bond the second end E2 to, for example, the wiring board 70. Note that in an embodiment in which localized protrusions are not a particular problem, the bonding material C may be formed over the entire connection terminal 62 as in the comparative example described above.

[0062] In this embodiment, the bonding material C for bonding the supporting conductor 61 and the connection terminal 62 is melted by heating the semiconductor module 100 in the inspection process P6. That is, the bonding process Q is realized by a part of the inspection process P6. Therefore, the manufacturing process of the semiconductor module 100 is simplified compared to the embodiment in which the step of melting the bonding material C is performed independently of the inspection process P6. In particular, in this embodiment, since the liquidus temperature Tl of the bonding material C is lower than the maximum junction temperature Tjmax of the semiconductor chip 40, the bonding material C can be melted and the supporting conductor 61 and the connection terminal 62 can be bonded by heating the semiconductor module 100 to the maximum junction temperature Tjmax.

[0063] C: Modification Specific modified aspects that can be added to the above-described embodiment are illustrated below. Two or more aspects selected from the following examples may be appropriately combined as long as they are not inconsistent.

[0064] (1) In the above embodiment, the connection terminal 62 has a square cross section, but the shape of the connection terminal 62 is not limited to the above embodiment. For example, as shown in Examples 1 to 3 in FIG. 8, an elongated member having a polygonal cross section may be used as the connection terminal 62. Also, an elongated member having a circular cross section may be used as the connection terminal 62.

[0065] (2) In the above embodiment, the tubular portion 610 of the supporting conductor 61 is cylindrical, but the shape of the supporting conductor 61 is not limited to the above embodiment. For example, a supporting conductor 61 having a rectangular tubular shape with a polygonal cross section may be used. In other words, the supporting conductor 61 is generally expressed as a conductive structure formed in a cylindrical shape into which the connecting terminal 62 can be inserted.

[0066] (3) In the above-described embodiment, an example was given of a configuration in which the accommodating portion 20 is formed by the housing 21, the sealing body 22, and the lid portion 23. However, the present disclosure is also applicable to a configuration in which the accommodating portion 20 is formed by a single resin material (full mold).

[0067] In the embodiment described above in which the semiconductor unit 10 is sealed with the soft sealing body 22, the connection terminal 62 is easily displaced by the action of an external force because the accommodation section 20 does not hold the connection terminal 62 as strongly as the accommodation section 20. Therefore, in the embodiment described above in which the accommodation section 20 includes the housing 21 and the soft sealing body 22, a configuration in which the support conductor 61 and the connection terminal 62 are joined using the joint 63 to suppress the displacement of the connection terminal 62 is particularly effective.

[0068] (4) In the plating step P3 of the above embodiment, the method of immersing the connection terminal 62 in the plating bath of the bonding material C stored in the storage container 80 has been exemplified, but the method of providing the bonding material C to the connection terminal 62 is not limited to the above example. For example, the connection terminal 62 may be immersed in a tank in which the bonding material C is molten.

[0069] (5) In the above embodiment, the inspection step P6 includes the bonding step Q. However, the bonding step Q of bonding the supporting conductor 61 and the connection terminal 62 to each other by the bonding portion 63 may be performed separately from the inspection step P6. For example, the bonding portion 63 may be formed by melting and solidifying the bonding material C between the pressing step P4 and the accommodation step P5. Also, for example, in the accommodation step P5, step P52 for forming the sealing body 22, the sealing body 22 is hardened by heating the semiconductor module 100. The bonding material C may be melted by heating in step P52, and solidified by cooling after melting, to form the bonding portion 63.

[0070] (6) In the embodiment described above, the accommodating step P5 is performed after the pressing step P4 is performed, but the pressing step P4 may be performed after the accommodating step P5 is performed. For example, in a configuration in which the second end E2 of the supporting conductor 61 opens on the exterior surface F of the accommodating portion 20, the connection terminal 62 may be inserted into the supporting conductor 61 after the accommodating portion 20 is formed.

[0071] (7) In the above embodiment, the semiconductor chip 40 is an RC-IGBT, but the embodiment of the semiconductor chip 40 is not limited to the above embodiment. For example, various electronic elements such as an IGBT (Insulated Gate Bipolar Transistor) or an SBD (Schottky Barrier Diode) may be used as the semiconductor chip 40. Also, a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) whose semiconductor layer is made of silicon (Si) or silicon carbide (SiC) may be used as the semiconductor chip 40. In the embodiment in which the semiconductor chip 40 is a MOSFET, the first electrode 41 is a drain electrode, and the second electrode 42 is a source electrode.

[0072] (8) The term "nth" (n is a natural number) in this application is used only as a formal and convenient label to distinguish each element in the description and does not have any substantial meaning. Therefore, there is no room for restrictive interpretation of the position of each element or the order of production, etc., based on the term "nth".

[0073] D: Notes From the above-described exemplary embodiments, the following configurations can be understood, for example.

[0074] A semiconductor module according to one aspect (aspect 1) of the present disclosure includes a mounting substrate, a semiconductor chip mounted on the mounting substrate, a cylindrical supporting conductor mounted on the mounting substrate, a housing portion for housing the mounting substrate, the semiconductor chip, and the supporting conductor, a connection terminal including a first end portion pressed into the supporting conductor and a second end portion protruding from the housing portion and electrically connected to the semiconductor chip, and a conductive first joint portion located between an inner wall surface of the supporting conductor and an outer wall surface of the connecting terminal, and joining the supporting conductor and the connecting terminal. In the above aspect, the supporting conductor and the connecting terminal are joined by the first joint portion, so that the displacement (and thus the falling off) of the connecting terminal can be suppressed compared to a configuration in which the connecting terminal is simply pressed into the supporting conductor.

[0075] In a specific example (Aspect 2) of Aspect 1, the solidus temperature of the first bonding portion exceeds the maximum environmental temperature that the semiconductor module is used in. In the above aspect, since the solidus temperature of the first bonding portion exceeds the maximum environmental temperature of the semiconductor module, it is possible to reduce the possibility that the first bonding portion will melt in the actual usage environment of the semiconductor module.

[0076] In a specific example (Aspect 3) of Aspect 1 or Aspect 2, the liquidus temperature of the first bonding portion is lower than the maximum junction temperature of the semiconductor chip. In the above aspects, since the liquidus temperature of the first bonding portion is lower than the maximum junction temperature (bonding portion temperature) of the semiconductor chip, it is possible to melt the bonding material and form the first bonding portion (i.e., bond the supporting conductor and the connection terminal) in the step of heating the semiconductor module to the maximum junction temperature.

[0077] In a specific example (Aspect 4) of any one of Aspects 1 to 3, the supporting conductor is joined to the mounting board by a second bonding portion, and the liquidus temperature of the first bonding portion is lower than the solidus temperature of the second bonding portion. According to the above aspects, the liquidus temperature of the first bonding portion for joining the connection terminal and the supporting conductor is lower than the solidus temperature of the second bonding portion for joining the supporting conductor and the mounting board. Therefore, the first bonding portion can bond the connection terminal and the supporting conductor by melting and solidifying the bonding material while maintaining the bonding between the mounting board and the supporting conductor by the second bonding portion.

[0078] In a specific example (Aspect 5) of any one of Aspects 1 to 4, the accommodating section includes a housing surrounding the mounting board, the semiconductor chip, and the supporting conductor, and a sealing body filled in an internal space of the housing, and the sealing body is softer than the housing. In a configuration in which the mounting board, the semiconductor chip, and the supporting conductor are sealed with a soft sealing body, the holding of the connection terminal by the accommodating section is weak, and the connection terminal is easily displaced, for example, by the action of an external force. Therefore, in a configuration in which the accommodating section includes a housing and a soft sealing body, the configuration of the present disclosure is particularly effective in suppressing the displacement of the connection terminal by bonding the supporting conductor and the connection terminal using the first bonding portion.

[0079] In a specific example (aspect 6) of any of aspects 1 to 5, the first bonding portion is formed on a portion of the connection terminal including the first end, and the second end is exposed from the first bonding portion. In a configuration in which a bonding material for forming the first bonding portion is provided over the entire connection terminal including the first end and the second end, the bonding material located near the second end may melt and then solidify, forming a local protrusion (lump). If a protrusion is formed near the second end, for example, installation of the second end on a wiring board or the like (for example, insertion into a mounting hole of a wiring board) may be hindered. According to a configuration in which the first bonding portion is formed only on a portion of the connection terminal including the first end, and the second end is exposed from the first bonding portion, the formation of a local protrusion near the second end due to melting of the bonding material that becomes the first bonding portion is suppressed. Therefore, the second end can be easily installed on, for example, a wiring board.

[0080] A method for manufacturing a semiconductor module according to one aspect (aspect 7) of the present disclosure includes a mounting step of placing a semiconductor chip and a cylindrical supporting conductor on a mounting substrate, and a joining step of joining the supporting conductor and the connecting terminal by a first joint portion between an inner wall surface of the supporting conductor and an outer wall surface of the connecting terminal, with a first end of the connecting terminal being press-fitted into the supporting conductor and a second end of the connecting terminal protruding from an accommodating portion that accommodates the mounting substrate, the semiconductor chip, and the supporting conductor. In the above aspect, since the supporting conductor and the connecting terminal are joined by the first joint portion, displacement (and therefore falling off) of the connecting terminal can be suppressed compared to a configuration in which the connecting terminal is simply press-fitted into the supporting conductor.

[0081] In a specific example (Aspect 8) of Aspect 7, the method further includes a press-fitting step of press-fitting the first end portion, on which the bonding material that becomes the first bonding portion is formed, into the supporting conductor before the joining step is performed, In the joining step, the first joint is formed by melting and solidifying the bonding material. In the above aspect, the first end portion on which the bonding material that becomes the first joint is formed is pressed into the supporting conductor. Therefore, compared to, for example, an aspect in which the bonding material is provided after the first end portion is pressed into the supporting conductor, the first joint can be easily provided between the inner wall surface of the supporting conductor and the outer wall surface of the connecting terminal.

[0082] In a specific example (Aspect 9) of Aspect 7 or Aspect 8, the bonding material is provided on the inside of the housing portion of the connection terminal, and the outside of the housing portion of the connection terminal is exposed from the bonding material. In the above aspects, the bonding material is provided on the inside of the housing portion of the connection terminal, and the outside of the housing portion of the connection terminal is exposed from the bonding material, so that the formation of a localized protrusion in the vicinity of the second end portion due to melting of the bonding material is suppressed. Therefore, the second end portion can be easily installed on, for example, a wiring board, etc.

[0083] In a specific example (Aspect 1) of any one of Aspects 7 to 9, an inspection step is included in which the semiconductor module is inspected in a heated state, and the bonding step is a step of melting and solidifying the bonding material by heating the semiconductor module in the inspection step. According to the above aspect, the bonding material for bonding the supporting conductor and the connection terminal is melted by heating the semiconductor module in the inspection step. In other words, the bonding step is realized as part of the inspection step. Therefore, the manufacturing process of the semiconductor module is simplified compared to an embodiment in which the step of melting the bonding material is carried out independently of the inspection step. [Explanation of symbols]

[0084] 100...semiconductor module, 200...heat dissipation mechanism, 10...semiconductor unit, 20...accommodation section, 21...housing, 22...sealing body, 23...lid section, 30...mounting board, 31...insulating board, 32...metal layer, 33...conductive pattern, 40...semiconductor chip, 41...first electrode, 42...second electrode, 50...wire, 60...external terminal, 61...supporting conductor, 610...cylindrical section, 611...first flange, 612...second flange, 614...inner wall surface, 62...connection terminal, 621...outer wall surface, 63...joint, 631...first part, 632...second part.

Claims

1. A mounting board; A semiconductor chip mounted on the mounting substrate; A cylindrical supporting conductor disposed on the mounting substrate; a housing portion that houses the mounting substrate, the semiconductor chip, and the supporting conductor; a connection terminal including a first end portion pressed into the supporting conductor and a second end portion protruding from the housing portion, the connection terminal being electrically connected to the semiconductor chip; a conductive first joint portion located between an inner wall surface of the supporting conductor and an outer wall surface of the connection terminal, the first joint portion joining the supporting conductor and the connection terminal; A semiconductor module comprising:

2. The solid-phase temperature of the first joint portion exceeds a maximum environmental temperature in which the semiconductor module is used. The semiconductor module of claim 1.

3. The liquidus temperature of the first junction is lower than the maximum junction temperature of the semiconductor chip.

3. The semiconductor module according to claim 1 or 2.

4. the supporting conductor is joined to the mounting substrate by a second joint portion; The liquidus temperature of the first joint is lower than the solidus temperature of the second joint. The semiconductor module of claim 1.

5. The storage section includes: a housing that encloses the mounting substrate, the semiconductor chip, and the supporting conductor; a sealant filled in the internal space of the housing, The sealing body is softer than the housing. The semiconductor module of claim 1.

6. the first joint portion is formed on a portion of the connection terminal including the first end portion, The second end is exposed from the first joint. The semiconductor module of claim 1.

7. a mounting step of placing the semiconductor chip and the cylindrical supporting conductor on a mounting substrate; a joining process of joining the supporting conductor and the connection terminal by a first joint portion between an inner wall surface of the supporting conductor and an outer wall surface of the connection terminal, in a state in which a first end of the connection terminal is press-fitted into the supporting conductor and a second end of the connection terminal protrudes from an accommodation portion that accommodates the mounting board, the semiconductor chip, and the supporting conductor; A method for manufacturing a semiconductor module comprising the steps of:

8. The method further includes a press-fitting step of press-fitting the first end portion, on which a bonding material that becomes the first bonding portion is formed, into the supporting conductor before the joining step is performed, In the bonding step, the bonding material is melted and solidified to form the first bonded portion. The method for manufacturing the semiconductor module according to claim 7.

9. The bonding material is disposed on a portion of the connection terminal that is located inside the housing portion, A portion of the connection terminal that is outside the housing portion is exposed from the bonding material. The method for manufacturing the semiconductor module according to claim 8.

10. an inspection step of inspecting the semiconductor module in a heated state; The bonding step is a step of melting and solidifying the bonding material by heating the semiconductor module in the inspection step. The method for manufacturing a semiconductor module according to claim 8 or 9.

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