JP2015026724A - Semiconductor module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor module which can inhibit deterioration in reliability of solder connection.SOLUTION: A semiconductor module 101 comprises: semiconductor chips 1, 2; a substrate 3; a housing; first lead-out terminals 21, 24; second lead-out terminals 22, 25; and connection parts 23, 26. The substrate 3 mounts the semiconductor chips 1, 2. The housing stores the substrate 3. The first lead-out terminals 21, 24 are mounted on the substrate 3 and extend in a direction crossing a principal surface of the substrate 3. The second lead-out terminals 22, 25 are provided on the side farther than the first lead-out terminals 21, 24 with respect to the substrate 3 when viewed from the substrate 3 in the above-described direction. The connection parts 23, 26 are provided inside the housing, for electrically connecting the second lead-out terminals 22, 25 with the first lead-out terminals 21, 24, respectively.

Description

  The present invention relates to a semiconductor module, and more particularly to a structure of a lead-out terminal mounted on a substrate of a semiconductor module.

  A semiconductor module generally includes a substrate, a semiconductor chip, lead-out terminals, and a casing (case). The substrate is fixed to a base constituting the bottom of the housing with a conductive adhesive such as solder (hereinafter, typically described as “solder”). The semiconductor chip and the lead-out terminal are mounted on the substrate and fixed to the substrate with solder. The lead-out terminal extends from the substrate to the outside of the housing. The semiconductor chip and the lead-out terminal are electrically connected by a bonding wire. Non-Patent Document 1 describes a semiconductor module having such a configuration (see p60 of Non-Patent Document 1).

Takahashi Yoshikazu, "2010 Power Module Assembly and Mounting Technology Thorough Explanation", Electronic Journal, June 14, 2010, p60

  When the bonding wire is formed after the lead-out terminal is soldered to the substrate, the bonding tool can come into contact with the lead-out terminal provided on the substrate. On the other hand, when soldering the lead-out terminal to the substrate after forming the bonding wire, it is necessary to raise the temperature for solder connection. If it does so, the existing solder (the solder which fixes the semiconductor chip to the board | substrate, the solder which fixes the board | substrate to the base, etc.) will be heated again, and the reliability of the existing solder will fall.

  Although it is conceivable to use a solder for the lead-out terminal having a lower melting point than that of the existing solder, the use of such a special solder increases the material cost. Moreover, even if such a low melting point solder is employed, the influence on the existing solder due to re-heating cannot be completely eliminated.

  Therefore, an object of the present invention is to provide a semiconductor module capable of suppressing a decrease in reliability of solder connection.

  A semiconductor module according to one aspect of the present invention includes a semiconductor chip, a substrate, a housing, a first derivation terminal, a second derivation terminal, and a connection portion. A semiconductor chip is mounted on the substrate. The housing accommodates the substrate. The first lead-out terminal is mounted on the substrate and extends in a direction intersecting with the main surface of the substrate. The second lead-out terminal is provided on the side farther than the first lead-out terminal with respect to the board when viewed from the board in the above direction. The connection portion is provided inside the housing and electrically connects the second lead-out terminal with the first lead-out terminal.

  ADVANTAGE OF THE INVENTION According to this invention, the semiconductor module which can suppress the fall of the reliability of solder connection can be provided.

It is sectional drawing along the XZ plane of the semiconductor module which concerns on Embodiment 1 of this invention. FIG. 2 is a plan view schematically showing the inside of the semiconductor module shown in FIG. 1. It is sectional drawing along the III-III line in FIG. It is the figure which showed the mode at the time of formation of a bonding wire. FIG. 6 is a cross-sectional view taken along the XZ plane of the semiconductor module according to the second embodiment. FIG. 6 is a cross-sectional view along the XZ plane of a semiconductor module according to a third embodiment. It is the figure which showed the other structure of the 2nd derivation | leading-out terminal. It is the figure which showed other structure of the 2nd derivation | leading-out terminal.

[Description of Embodiment of Present Invention]
First, embodiments of the present invention will be listed and described.

  (1) The semiconductor module which concerns on embodiment of this invention is provided with a semiconductor chip, a board | substrate, a housing | casing, a 1st derivation | leading-out terminal, a 2nd derivation | leading-out terminal, and a connection part. A semiconductor chip is mounted on the substrate. The housing accommodates the substrate. The first lead-out terminal is mounted on the substrate and extends in a direction intersecting with the main surface of the substrate. The second lead-out terminal is provided on the side farther than the first lead-out terminal with respect to the board when viewed from the board in the above direction. The connection portion is provided inside the housing and electrically connects the second lead-out terminal with the first lead-out terminal.

  In this semiconductor module, the terminal is divided into a first lead-out terminal and a second lead-out terminal, and a connection portion for electrically connecting the second lead-out terminal to the first lead-out terminal is provided inside the housing. Accordingly, the length of the first lead-out terminal can be determined so that the terminal does not come into contact with the bonding tool when the bonding wire is formed.

  And by setting it as such a structure, after soldering a 1st derivation | leading-out terminal to a board | substrate, before connecting a 2nd derivation | leading-out terminal to a 1st derivation | leading-out terminal by a connection part, wire bonding can be implemented. Thus, the soldering of the first lead-out terminal can be performed simultaneously with the soldering of the semiconductor chip before the wire bonding is performed. Therefore, according to this semiconductor module, it is possible to avoid a decrease in the reliability of solder connection caused by performing the temperature increase for solder connection a plurality of times. Further, it is not necessary to select a low melting point solder for the first lead-out terminal, and an increase in solder material cost can be suppressed.

  The direction in which the first lead-out terminal extends intersects the main surface of the substrate means that the direction in which the first lead-out terminal extends is orthogonal or substantially orthogonal to the main surface of the substrate. The term “substantially orthogonal” includes the case of crossing in a state shifted from the orthogonal state within a range of ± 10 ° or less, for example. The extending direction of the first lead-out terminal may optimally intersect with the main surface of the substrate at an angle of 90 °.

  The phrase “the connection portion is provided inside the housing” includes both the case where the connection portion is provided inside the housing and the case where the connection portion is configured integrally with the wall portion of the housing. Moreover, the structure of a connection part is not specifically limited. Various connection forms such as sockets, screwing, connectors, and welding (for example, laser welding) may be employed.

  (2) Preferably, a housing | casing has opening in the surface facing the main surface of a board | substrate. The semiconductor module further includes a lid provided in the opening. The second lead-out terminal is provided integrally with the lid.

  With such a configuration, the second lead-out terminal can be disposed simultaneously with the attachment to the opening of the lid. Therefore, according to this semiconductor module, the arrangement of the second lead-out terminals is facilitated.

(3) More preferably, the connection portion is provided integrally with the lid.
With such a configuration, the lid and the connecting portion are configured as one component. Therefore, according to this semiconductor module, the number of parts can be reduced.

  (4) Preferably, a 2nd derivation | leading-out terminal contains the drawer part pulled out to the exterior of the said housing | casing. The second lead-out terminal is configured such that the lead-out portion is displaced from the first lead-out terminal when the semiconductor module is viewed in plan along the direction intersecting the main surface of the substrate.

  With such a configuration, the drawing position of the second lead-out terminal to the outside of the housing can be made constant regardless of the arrangement of the first lead-out terminal. Alternatively, the drawing position of the second lead-out terminal to the outside of the housing can be changed without changing the arrangement of the first lead-out terminal. Therefore, according to this semiconductor module, the degree of freedom in design is improved.

(5) Preferably, a connection part contains a socket.
According to this configuration, the second lead-out terminal can be easily connected to the first lead-out terminal.

(6) Preferably, a connection part is provided in a 2nd derivation | leading-out terminal.
With such a configuration, the connection portion is not affected by a temperature rise (such as a reflow process) when the semiconductor chip and the first lead-out terminal are soldered to the substrate. Therefore, according to this semiconductor module, the reliability of the connecting portion can be ensured.

(7) Preferably, the semiconductor chip includes a wide band gap semiconductor.
As described above, by adopting a solder for the lead-out terminal having a lower melting point than that for the semiconductor chip, the semiconductor chip is soldered to the substrate to form a bonding wire, and then the lead-out terminal is soldered to the substrate. It is also possible to attach it. However, in a semiconductor module using a wide bandgap semiconductor that is used at a higher temperature than a silicon-based semiconductor element, the types of solder that can be used are limited, so it may not be possible to select such solder. . According to this semiconductor module, the soldering of the first lead-out terminal can be performed simultaneously with the soldering of the semiconductor chip before the wire bonding is performed, and thus the above-described problem does not occur.

Since the semiconductor chip includes a wide band gap semiconductor, the chip area can be reduced as compared with a silicon-based semiconductor element having the same current driving capability. Therefore, according to this semiconductor module, the semiconductor module can be reduced in size by reducing the mounting area of the semiconductor chip.
[Details of the embodiment of the present invention]
Hereinafter, embodiments of the present invention will be described with reference to the drawings. A plurality of embodiments will be described below, but it is planned from the beginning of the application to appropriately combine the configurations described in the embodiments. In the following description, the same or corresponding elements are denoted by the same reference numerals, and detailed description thereof will not be repeated.

  The X axis, the Y axis, and the Z axis shown in the drawings are axes orthogonal to each other. A plane defined by the X axis and the Y axis is referred to as an XY plane. The XY plane is defined as a surface on which the semiconductor module according to the embodiment of the present invention is installed. In one example, the XY plane is a horizontal plane. However, the XY plane is not limited to a horizontal plane. For example, the XY plane may be a vertical plane.

<Embodiment 1>
The configuration of the semiconductor module according to the first embodiment of the present invention will be described with reference to FIGS. 1 is a cross-sectional view taken along the XZ plane of a semiconductor module according to Embodiment 1 of the present invention. 2 is a plan view schematically showing the inside of the semiconductor module shown in FIG. 1, and FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2 and 3 show a state where the lid of the semiconductor module is removed.

  With reference to FIGS. 1 to 3, the semiconductor module 101 according to the first embodiment includes semiconductor chips 1 and 2, a substrate 3, first lead terminals 21 and 24, second lead terminals 22 and 25, Connection portions 23 and 26 and wires 27 and 28 are provided. The semiconductor module 101 further includes a base 11, a frame body 12, a lid body 31, and a sealing resin 29. The base 11, the frame body 12, and the lid body 31 constitute a housing (case) for the semiconductor module 101.

  In the first embodiment, each of the semiconductor chips 1 and 2 includes a wide band gap semiconductor. The wide band gap semiconductor is composed of SiC (silicon carbide), GaN (gallium nitride), diamond, or the like.

  Wide bandgap semiconductor elements are characterized by high breakdown voltage, low on-resistance, stable operation in a high temperature environment, and the like as compared with silicon semiconductor elements. By configuring each of the semiconductor chips 1 and 2 with a wide band gap semiconductor, the chip area can be reduced as compared with a silicon-based semiconductor element having the same current driving capability, and as a result, the semiconductor module 101 can be downsized. can do.

  In the first embodiment, each of semiconductor chips 1 and 2 is a power semiconductor chip made of, for example, SiC. In one embodiment, each of the semiconductor chips 1 and 2 is a power MOSFET (Metal Oxide Semiconductor FET). In the case of a MOSFET formed of SiC, a diode built in the MOSFET can be used as a freewheel diode, so that the number of semiconductor chips accommodated in the housing can be reduced.

  The substrate 3 includes an insulating plate 4, electrode patterns 5 a and 5 b, and a copper plate 6. The electrode patterns 5 a and 5 b are arranged on one main surface of the insulating plate 4. The copper plate 6 is disposed on the other main surface of the insulating plate 4.

  The substrate 3 is disposed on the base 11 so that the copper plate 6 faces the base 11, and is fixed to the base 11 with solder 7. The base 11 may be a metal base containing a metal such as aluminum (Al) or copper (Cu). The base 11 can function as a heat radiating plate for releasing the heat generated by the semiconductor chips 1 and 2 to the outside of the housing. The base 11 can also be used as a ground electrode.

  The semiconductor chips 1 and 2 are mounted on the substrate 3 and fixed on the electrode pattern 5a by solders 8a and 8b, respectively. The semiconductor chip 1 is electrically connected to the electrode pattern 5b by wires 27. The semiconductor chip 2 is electrically connected to the electrode pattern 5a by wires 28. The wires 27 and 28 are formed using a bonding tool for wire bonding. Ball bonding may be used for wire bonding, or wedge bonding may be used.

  The first lead-out terminal 21 is disposed on the electrode pattern 5b and is fixed to the electrode pattern 5b with solder 8c. The first lead-out terminal 21 extends in the direction intersecting the main surface of the substrate 3 (Z-axis direction) and is connected to the connection portion 23.

  The second lead-out terminal 22 is provided on the side farther than the first lead-out terminal 21 with respect to the board 3 when viewed from the board 3 in the direction intersecting the main surface (Z-axis direction). The second lead-out terminal 22 has a lead portion 22a and an extending portion 22b. A connecting portion 23 is provided at the end of the lead-out portion 22a. The lead-out portion 22a extends in the Z-axis direction and is pulled out from the inside of the housing through the lid body 31. The extending portion 22 b is disposed along the upper surface 30 of the lid body 31. A bus bar 51 extending in the Y-axis direction is disposed on the extension 22b (FIG. 1). By tightening the screw 53, the bus bar 51 and the extending portion 22 b of the second lead-out terminal 22 are fixed to the upper surface 30 of the lid 31.

  In addition, the extension part 22b is extended in the same direction (Z-axis direction) as the drawer | drawing-out part 22a until the cover body 31 is attached. Then, after the lid body 31 is fixed to the frame body 12 with screws or the like (not shown), the extended portion 22 b is formed by bending the second lead-out terminal 22 along the upper surface 30 of the lid body 31.

  The connection portion 23 is provided inside the housing and electrically connects the second lead-out terminal 22 with the first lead-out terminal 21. As an example, the connection portion 23 is a socket provided at an end portion of the second lead-out terminal 22, and a conduction portion inside the socket is electrically connected to the second lead-out terminal 22. The first lead-out terminal 21 and the second lead-out terminal 22 are electrically connected by fitting the tip of the first lead-out terminal 21 into the socket female portion of the connection portion 23.

  As described above, in the first embodiment, the external lead-out terminal drawn out from the substrate 3 to the outside of the housing is divided into the first lead-out terminal 21 and the second lead-out terminal 22. The second derivation terminal 22 is electrically connected to the first derivation terminal 21 through the connection portion 23. That is, the second lead-out terminal 22 is configured separately from the first lead-out terminal 21 and is retrofitted using the connection portion 23 to the first lead-out terminal 21 fixed to the substrate 3 with the solder 8c.

  The length of the first lead-out terminal 21 in the Z-axis direction is determined based on the operating range of the bonding tool so that the bonding tool (not shown) does not contact the first lead-out terminal 21 when forming the wires 27 and 28. The As an example, the length of the first lead-out terminal 21 in the Z-axis direction is preferably 20 mm or less, and more preferably 10 mm or less.

  With such a configuration, it is possible to perform wire bonding for forming the wires 27 and 28 after the first lead-out terminal 21 is soldered onto the substrate together with the semiconductor chips 1 and 2 (FIG. 3). . The second lead terminal 22 is connected to the first lead terminal 21 after the wires 27 and 28 are formed.

  The configurations of the first derivation terminal 24, the second derivation terminal 25, and the connection portion 26 are the same as the configurations of the first derivation terminal 21, the second derivation terminal 22, and the connection portion 23, respectively. Since the description of the first derivation terminal 24, the second derivation terminal 25, and the connection portion 26 overlaps with the description of the first derivation terminal 21, the second derivation terminal 22, and the connection portion 23, it will not be repeated.

  The frame body 12 is formed of an insulator (for example, resin). The frame body 12 is formed so as to surround the base 11 and constitutes the side wall of the housing of the semiconductor module 101. The frame 12 and the base 11 accommodate the substrate 3 on which the semiconductor chips 1 and 2 are mounted. The substrate 3 is sealed with a sealing resin 29 inside the housing (FIG. 1).

  An opening 20 is formed on the surface of the housing facing the base 11. A lid 31 is provided in the opening 20. The lid body 31 is formed of an insulator (for example, resin) similarly to the frame body 12. The lid body 31 is fixed to the frame body 12 by screws or the like (not shown) and closes the opening 20.

  In the first embodiment, the soldering (die bonding) of the semiconductor chips 1 and 2 to the substrate 3 and the soldering of the first lead-out terminals 21 and 24 to the substrate 3 are, for example, a reflow process using a reflow furnace. At once. Thereafter, in the wire bonding step, the wires 27 and 28 are formed using a bonding tool. Further, after the wires 27 and 28 are formed, the second lead-out terminals 22 and 25 are connected to the first lead-out terminals 21 and 24 using the connection portions 23 and 26, respectively.

  FIG. 4 is a view showing a state when the bonding wire is formed. Referring to FIG. 4, wire bonding is performed using a bonding tool 60. When the bonding tool 60 moves, the bonding tool 60 is pulled up to some extent in the Z-axis direction. However, as shown in phantom by the dotted line, when the lead terminal extending from the substrate is long, the bonding tool 60 contacts the lead terminal.

  In order to avoid contact between the bonding tool 60 and the lead terminal, it is also conceivable to solder the lead terminal to the substrate after the wire bonding process. However, this method requires a temperature rise in order to solder the lead-out terminal, and reduces the reliability of the existing solders 7, 8a, 8b. Although it is conceivable to use solder having a melting point lower than that of the solders 7, 8a, 8b as the lead terminal solders 8c, 8d, the use of such special solders may increase the material cost. In particular, in the first embodiment, the semiconductor chips 1 and 2 include wide band gap semiconductors, and the semiconductor module 101 operates at a high temperature. For this reason, the choice of solder is restricted, and there is a possibility that the special solder as described above cannot be selected.

  Therefore, in the first embodiment, the lead-out terminal is divided into the first lead-out terminal 21 (24) and the second lead-out terminal 22 (25), and the second lead-out terminal 22 (25) is connected by the connecting portion 23 (26). It is possible to connect to the first lead-out terminal 21 (24) later. Then, the first lead-out terminal 21 (24) is soldered together with the die bonding of the semiconductor chips 1 and 2, and after the wire bonding is performed, the second lead-out terminal 22 (25) is first lead out by the connecting portion 23 (26). Connected to terminal 21 (24).

  Therefore, according to the first embodiment, a reheating step for soldering the lead-out terminal after the wire bonding is not required, and a decrease in reliability of existing solder due to the reheating can be avoided.

<Embodiment 2>
In the second embodiment, the second lead terminals 22 and 25 and the connection parts 23 and 26 are provided integrally with the lid.

  FIG. 5 is a cross-sectional view taken along the XZ plane of the semiconductor module according to the second embodiment. Referring to FIG. 5, this semiconductor module 102 is different from the semiconductor module 101 according to the first embodiment shown in FIG.

  In other words, in the semiconductor module 102, the second lead-out terminals 22 and 25 and the connection parts 23 and 26 are configured integrally with the lid 31. The connection parts 23 and 26 are provided on the inside of the housing of the lid 31. As the lid body 31 is attached to the frame body 12, the leading ends of the first lead-out terminals 21 and 24 are fitted into the connection portions 23 and 26, respectively, and the first lead-out terminal 21 (24) and the second lead-out terminal 22 (25). Are electrically connected.

  Also in the second embodiment, the lead-out terminal is divided into the first lead-out terminal 21 (24) and the second lead-out terminal 22 (25), and the same effect as in the first embodiment can be obtained. Furthermore, according to the second embodiment, the connection of the second lead-out terminals 22 and 25 to the first lead-out terminals 21 and 24 can be performed simultaneously with the attachment of the lid 31 to the frame body 12. Moreover, since the connection parts 23 and 26 are provided integrally with the cover body 31, the number of parts is also reduced.

  In the above description, the second lead-out terminals 22 and 25 and the connecting portions 23 and 26 are provided integrally with the lid 31. However, the connecting portions 23 and 26 are configured separately from the lid 31. May be.

<Embodiment 3>
The connection method of the 2nd derivation | leading-out terminal 22 (25) and the 1st derivation | leading-out terminal 21 (24) can take a various method. For example, the first lead-out terminal 21 (24) and the second lead-out terminal 22 (25) may be connected by screwing.

  FIG. 6 is a cross-sectional view along the XZ plane of the semiconductor module according to the third embodiment. With reference to FIG. 6, in this semiconductor module 103, the second lead-out terminal 22 is connected to the first lead-out terminal 21 by a screw 41. Similarly, the second lead terminal 25 is connected to the first lead terminal 24 by a screw 42.

  Other configurations of the semiconductor module 103 are the same as those of the semiconductor module 101 according to the first embodiment.

  Although not particularly illustrated, welding (for example, laser welding) may be used as a method of connecting the second lead terminal 22 (25) and the first lead terminal 21 (24), or the first lead terminal 21 ( 24) or a structure like a clip at the tip of the second lead-out terminal 22 (25), and the other lead-out terminal may be held.

  As another embodiment, the configuration of the second lead-out terminal 22 (25) is the second lead-out when the semiconductor module is viewed in a plan view from the Z-axis direction as shown in FIG. 7 and FIG. 8 as an example. The second lead terminal 22 (25) may be formed so that the lead portion of the terminal 22 (25) is displaced from the first lead terminal 21 (24).

  With such a second lead-out terminal 22 (25), for example, even if the arrangement of the first lead-out terminal 21 (24) on the substrate 3 is changed, the second lead-out terminal 22 (25) is pulled out of the housing. The position can be constant. Or, conversely, when it is desired to change the position where the second lead-out terminal 22 (25) is pulled out of the housing, the second lead-out terminal 22 is not changed without changing the arrangement of the first lead-out terminal 21 (24) on the substrate 3. The extraction position of (25) can be changed.

  In each of the above embodiments, solder is used for fixing the substrate 3 to the base 11 and fixing the semiconductor chips 1 and 2 and the first lead-out terminals 21 and 24 to the substrate 3. However, a conductive adhesive other than solder may be used.

  In addition, the number and layout of the semiconductor chips described in the above embodiments are examples, and are not limited to those described above. Further, the number of external lead-out terminals (two in each of the above embodiments) and the layout constituted by the first lead-out terminals and the second lead-out terminals are also examples, and are not limited to those described above. .

  Further, in each of the above embodiments, the connection portions 23 and 26 are provided on the second lead-out terminals 22 and 25 side, but may be provided on the first lead-out terminals 21 and 24 side.

  The embodiments disclosed this time are also scheduled to be implemented in appropriate combinations. The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and is intended to include meanings equivalent to the scope of claims for patent and all modifications within the scope.

DESCRIPTION OF SYMBOLS 1, 2 Semiconductor chip 3 Board | substrate 4 Insulation board 5a, 5b Electrode pattern 6 Copper plate 7, 8a-8d Solder 11 Base 12 Frame 20 Opening part 21, 24 1st lead-out terminal 22, 25 2nd lead-out terminal 22a, 25a Lead-out part 22b, 25b Extension part 23, 26 Connection part 27, 28 Wire 29 Sealing resin 30 Upper surface 31 Case 51, 52 Bus bar 41, 42, 53, 54 Screw 60 Bonding tool 101-103 Semiconductor module

Claims (7)

A semiconductor chip;
A substrate on which the semiconductor chip is mounted;
A housing for housing the substrate;
A first lead-out terminal mounted on the substrate and extending in a direction intersecting the main surface of the substrate;
A second lead-out terminal provided on a side farther than the first lead-out terminal with respect to the board when viewed from the board in the direction;
A semiconductor module, comprising: a connection portion provided in the housing for electrically connecting the second lead-out terminal to the first lead-out terminal. The housing has an opening on a surface facing the main surface of the substrate,
The semiconductor module further includes a lid provided in the opening,
The semiconductor module according to claim 1, wherein the second lead-out terminal is provided integrally with the lid body.   The semiconductor module according to claim 2, wherein the connection portion is provided integrally with the lid. The second lead-out terminal includes a lead-out portion that is pulled out to the outside of the housing,
The said 2nd derivation | leading-out terminal is comprised so that the said drawer | drawing-out part may shift | deviate from the said 1st derivation | leading-out terminal when the said semiconductor module is planarly viewed along the said direction. The semiconductor module according to item.   The semiconductor module according to claim 1, wherein the connection portion includes a socket.   The semiconductor module according to claim 1, wherein the connection portion is provided in the second lead-out terminal.   The semiconductor module according to claim 1, wherein the semiconductor chip includes a wide band gap semiconductor.

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