JP2014127657A - Manufacturing method for semiconductor power converter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method for a power semiconductor device, whereby the device can easily be manufactured with high material efficiency at a low cost.SOLUTION: According to an embodiment, a manufacturing method for a semiconductor power converter comprises: joining first and second semiconductor elements to a first area on one side with respect to a center line C on the first joining surface of a first conductor; joining third and fourth semiconductor elements to a second area on the other side; joining a spacer and a lead frame 70 in order onto the first or fourth semiconductor element; joining a second conductor with a second joint face onto the lead frame such that the second joint face is opposite to the first joint face of the first conductor; connecting the electrodes of the first and third semiconductor elements and the signal terminal 50 of the lead frame by means of a conducting wire; covering the first conductor and the second conductor with an insulating material, thereby forming an insulator 52; and cutting the insulator, the first conductor and the second conductor along the center line C of the first conductor, thereby separating them into a first module including the first and second semiconductor elements, and a second module including the third and fourth semiconductor elements.

Description

  Embodiments described herein relate generally to a method for manufacturing a semiconductor power conversion device.

  In recent years, for the purpose of improving the fuel efficiency of automobiles, the spread of hybrid cars using both an internal combustion engine and a motor is rapidly progressing. On the other hand, commercialization of electric vehicles that can be driven by motors is also progressing. In order to realize these automobiles, a power conversion device that performs conversion from DC power to AC power and conversion from AC power to DC power is required between the battery and the motor.

  In hybrid vehicles and electric vehicles, miniaturization and high reliability of semiconductor power conversion devices are required. In order to achieve miniaturization and high reliability of the semiconductor power conversion device, a semiconductor power conversion device with good cooling efficiency is required. As a method for realizing this, there has been proposed a double-sided heat dissipation type power converter structure in which a conductor is connected to the front and back surfaces of a semiconductor element and heat is radiated from the conductor to a cooler.

JP 2003-258166 A JP 2007-068302 A

  In a double-sided heat dissipation type power semiconductor device, it is necessary to expose the conductor from the device on the surface to be radiated to the cooler. However, it is difficult to expose the conductor in the manufacturing process of the device. For example, these semiconductor devices generally have a structure in which a semiconductor element and a conductor are molded with a resin, but it is impossible to make the dimensions, flatness, and assembly accuracy of the conductor zero. Therefore, the conductor is not necessarily exposed from the resin, and a grinding process is required to expose the conductor.

  The amount of grinding in the grinding process decreases as the size and flatness of the conductor and the assembly accuracy are improved. However, a high-precision member and a high-precision grinding facility are required, which increases the product cost. Conversely, if the grinding amount is large, the material efficiency is poor and the process time becomes long. Moreover, when setting a workpiece | work to a grinding equipment, it is necessary to fix each workpiece | work firmly, and a process becomes complicated.

  The present invention has been made in view of the above points. An object of the present invention is to provide a method of manufacturing a power semiconductor device that is simple, has high material efficiency, and can be manufactured at low cost.

  According to the embodiment, the method for manufacturing a semiconductor power conversion device has different electrodes on the front and back surfaces in the first region on one side of the center line of the first conductor on the first joint surface of the first conductor. The plate-like first semiconductor element and the second semiconductor element are joined such that one of the electrodes is in contact with the first joint surface, and on the first joint surface of the first conductor, opposite to the center line A plate-like third semiconductor element and a fourth semiconductor element each having different electrodes on the front and back surfaces are joined to the second region on the side so that one of the electrodes is in contact with the first joining surface; A spacer made of a conductor is joined to each electrode of the fourth semiconductor element, and the island connection portion of the lead frame having two sets of power terminals, two sets of signal terminals, and two sets of island connection portions On first and second semiconductor elements Bonding to the spacer and the spacer on the third and fourth semiconductor elements, respectively, and joining one of the set of power terminals to the first region of the first conductor, One of the two conductors is joined to the second region of the first conductor, and the second conductor having a second joint surface is connected to the second conductor so that the second joint surface faces the first joint surface of the first conductor. Bonding on the island connection portion of the set, connecting the electrode of the first semiconductor element and one set of signal terminals with a conducting wire, and connecting the electrode of the third semiconductor element and another set of signal terminals with a conducting wire A base end portion of the two sets of electrode terminals, a base end portion of the two sets of signal terminals, and the first conductor and the second conductor are covered with an insulating material to form an insulator, and the insulator, The first conductor and the second conductor are cut along a center line of the first conductor, and the first and second conductors are cut. Separated into a first module including a second semiconductor element and a second module including the third and fourth semiconductor elements, leaving the island connection portion, the power terminal, and the signal terminal of the lead frame, In the manufacturing method, the other part of the lead frame is cut off.

FIG. 1 is a perspective view showing a semiconductor power conversion device according to a first embodiment with a circuit board removed. FIG. 2 is a perspective view of the semiconductor module as seen from different directions. FIG. 3 is a perspective view showing an internal structure through a mold of the semiconductor module. FIG. 4 is an exploded perspective view showing components of the semiconductor module. FIG. 5 is a front view showing the semiconductor module. FIG. 6 is a perspective view showing a state where a first conductor is mounted on the first fixing jig in the manufacturing process. FIG. 7 is a perspective view showing a state in which a first conductor and a split jig are attached to the first fixing jig in the manufacturing process of the semiconductor module. FIG. 8 is a perspective view showing a state in which a connection body is placed on the first conductor in the manufacturing process of the semiconductor module. FIG. 9 is a perspective view showing a state where a first semiconductor element, a second semiconductor element, a third semiconductor element, and a fourth semiconductor element are placed on the connection body in the manufacturing process of the semiconductor module. FIG. 10 is a perspective view showing a state in which a connection body is placed on the first to fourth semiconductor elements in the manufacturing process of the semiconductor module. FIG. 11 is a perspective view showing a state in which first to fourth convex conductors are placed on the connection body in the manufacturing process of the semiconductor module. FIG. 12 is a perspective view showing a state in which a lead frame is placed on the first fixing jig and the convex conductor in the manufacturing process of the semiconductor module. FIG. 13 is a perspective view showing a state in which a connection body is placed on the lead frame in the manufacturing process of the semiconductor module. FIG. 14 is a perspective view showing a state in which a second conductor is placed on the connection body and the lead frame in the manufacturing process of the semiconductor module. FIG. 15 is a perspective view showing a state in which a second fixing jig is placed on the first fixing jig and the lead frame in the manufacturing process of the semiconductor module. FIG. 16 is a perspective view showing a state in which a weight is placed on the second conductor and the second fixing jig in the manufacturing process of the semiconductor module. FIG. 17 is a perspective view showing a state in which constituent members are joined by a connecting body (solder) and the first and second fixing jigs and the split jig are removed in the manufacturing process of the semiconductor module. FIG. 18 is a perspective view showing a wire bonding step in the manufacturing process of the semiconductor module. FIG. 19 is a perspective view showing a step of forming an insulator by resin molding in the manufacturing process of the semiconductor module. FIG. 20 is a perspective view showing a step of cutting the insulator, the first and second conductors, and the lead frame in the manufacturing process of the semiconductor module. FIG. 21 is a perspective view showing the first and second modules cut and separated in the manufacturing process of the semiconductor module. FIG. 22 is a plan view showing a process of cutting the first and second conductors and the lead frame in the manufacturing method according to the second embodiment.

  Hereinafter, a semiconductor power conversion device and a manufacturing method thereof according to embodiments will be described in detail with reference to the drawings. Each figure is a schematic diagram for promoting an understanding of the embodiment and its shape, dimensions, ratio, etc. are different from the actual apparatus, but these are considered in consideration of the following description and known techniques. The design can be changed as appropriate.

(First embodiment)
FIG. 1 is a perspective view of the semiconductor power conversion device according to the first embodiment with the control circuit board removed.
As shown in FIG. 1, a semiconductor power conversion device 10 includes a cooler 12, a support frame 14 fixed on the cooler 12, and a plurality of semiconductor modules mounted on the cooler and supported by the support frame. 16 is provided. The cooler 12 has a flat rectangular parallelepiped cooling block 18 having a flat rectangular heat receiving surface. The cooling block 18 is made of aluminum, for example. In the cooling block 18, a coolant channel 20 is formed through which a cooling medium such as water flows.

  The support frame 14 integrally includes a rectangular outer frame having a size corresponding to the heat receiving surface and a plurality of parallel connection beams extending between the outer frames, and the outer frame and the connection beams, for example, form four rows. Are arranged in a rectangular shape. The support frame 14 is provided with a plurality of bus bars having a plurality of connection terminals 24 electrically connected to a semiconductor module 16 described later, a plurality of input terminals 28, and two sets of three-phase output terminals 30. ing. A plurality of bus bar connection terminals 24 are arranged at intervals along each side edge of each installation space. And the support frame 14 is shape | molded by resin integrally with the some terminal by insert mold, for example. Further, the support frame 14 is fixed on the heat receiving surface of the cooling block 18 by, for example, a plurality of screws.

  As shown in FIG. 1, for example, six semiconductor modules 16 are installed on the support frame 14 in four rows. In each row, six semiconductor modules 16 are arranged in the installation space of the support frame 14, and the bottom surface of each semiconductor module is installed on the heat receiving surface of the cooler 12 via an insulating sheet (not shown). The power terminal of each semiconductor module 16 contacts the connection terminal 24 of the bus bar and is electrically connected to the bus bar. Further, the plurality of signal terminals 50 of each semiconductor module 16 protrude upward.

  The semiconductor power conversion device 10 includes a semiconductor circuit 16 and a control circuit board (not shown) that controls input / output and operation of the entire device. The control circuit board is formed in a rectangular shape having a size substantially equal to that of the support frame 14. The control circuit board 32 is placed on the semiconductor module 16 and is attached to the support frame 14 with a fixing screw (not shown). The signal terminal 50 of each semiconductor module 16 is electrically connected to the control circuit board 32.

Next, the semiconductor module 16 constituting the semiconductor power conversion device will be described in detail.
2 is a perspective view showing the semiconductor module, FIG. 3 is a perspective view showing the internal structure through the mold resin body of the semiconductor module, and FIG. 4 is an exploded perspective view showing the components of the semiconductor module. FIG. 5 is a front view showing the semiconductor module.

  As shown in FIGS. 2 to 4, the semiconductor module 16 is configured as a so-called double-sided heat radiation type and vertical mounting type semiconductor power conversion device. That is, the semiconductor module 16 includes, for example, a first prism-shaped conductor 34 formed of copper, a second prism-shaped second conductor 36 formed of copper, and a gap between the first and second conductors. And a first semiconductor element 38 and a second semiconductor element 40 which are bonded to these conductors.

  As for the 1st conductor 34, one main surface (side surface) comprises the rectangular-shaped joining surface (1st joining surface) 34a, Furthermore, the bottom face 34b orthogonal to this joining surface comprises the thermal radiation surface. The second conductor 36 is substantially equal in length to the first conductor 34 and has a thickness (width) smaller than that of the first conductor 34, for example, about one third, and further has a height. However, it is formed lower than the height of the first conductor 34. In the second conductor 36, one main surface (side surface) constitutes a rectangular joining surface (second joining surface) 36a, and a bottom surface 36b orthogonal to the joining surface constitutes a heat dissipation surface. The second conductor 36 is disposed such that the joint surface 36a faces the joint surface 34a of the first conductor 34 in parallel and the bottom surface 36b is located on the same plane as the bottom surface 34b of the first conductor 34. Has been.

  The first semiconductor element 38 is a power semiconductor element, for example, an IGBT (insulated gate bipolar transistor), and the second semiconductor element 40 includes a diode. The first semiconductor element 38 is formed in a rectangular plate shape, and configures different electrodes on the front surface and the back surface. A plurality of, for example, four connection terminals 38 a are formed on one surface of the first semiconductor element 38. The front and back surfaces of the first semiconductor element 38 are covered with an insulating film, for example, a polyimide film, except for the electrode portion and the connection terminal portion.

  The second semiconductor element 40 is formed in a rectangular plate shape, and configures different electrodes on the front surface and the back surface. The front and back surfaces of the second semiconductor element 38 are covered with an insulating film, for example, a polyimide film, except for the rectangular electrode portion.

  The first semiconductor element 38 is disposed in parallel with the bonding surface 34a of the first conductor 34, and one electrode is connected to the bonding surface 34a of the first conductor 34 by a first connecting body, for example, a rectangular solder sheet 42a. It is joined. The second semiconductor element 40 is disposed in parallel with the bonding surface 34 a of the first conductor 34, and is further disposed alongside the first semiconductor element 38 with a gap in the longitudinal direction of the first conductor 34. One electrode of the second semiconductor element 40 is bonded to the bonding surface 34a of the first conductor 34 by a second connecting body, for example, a rectangular solder sheet 42a.

As described above, the first semiconductor element 38 and the second semiconductor element 40 are arranged in parallel to the bonding surface 34a of the first conductor 34 and perpendicular to the bottom surface 34b of the first conductor.
Further, a fifth connection body, for example, a rectangular solder sheet 42e is provided on the joint surface 34a of the first conductor 34, and is located side by side with respect to the first semiconductor element 38.

  A first convex conductor (spacer) 44a for positioning is joined to the other electrode of the first semiconductor element 38 via a third connection body, for example, a rectangular solder sheet 42c. The first convex conductor 44a is made of, for example, copper, and includes a flat rectangular parallelepiped main body and a rectangular parallelepiped convex portion 45a that protrudes from one main surface of the main body and has a smaller diameter than the main body. Have. In the first convex conductor 44a, the flat main surface side of the main body is electrically and mechanically joined to the electrode of the first semiconductor element 38 by the solder sheet 42c.

A second convex conductor (spacer) 44b for positioning is joined to the other electrode of the second semiconductor element 40 via a fourth connecting body, for example, a rectangular solder sheet 42d. The second convex conductor 44b is made of, for example, copper, and includes a flat rectangular parallelepiped main body and a rectangular parallelepiped convex portion 45b that protrudes from one main surface of the main body and is smaller in diameter and flat than the main body. Have. In the second convex conductor 44b, the flat main surface side of the main body is electrically and mechanically joined to the electrode of the second semiconductor element 40 by the solder sheet 42d.
The first and second convex conductors 44a and 44b are not limited to separate bodies, and two main bodies may be integrally formed, and the two convex portions may be provided on a common main body.

  As shown in FIGS. 2 to 4, the semiconductor module 16 is a rectangular plate that is continuous with a first power terminal 46 a, a second power terminal 46 b, and a second power terminal, each of which is constituted by a lead frame made of a conductive metal plate described later. A plurality of, for example, five signal terminals 50 are provided.

  The first power terminal 46a is formed independently, and the base end portion thereof is joined to the joining surface 34a of the first conductor 34 by the solder sheet 42e. The first power terminal 46a protrudes from the one end of the first conductor 34 in the longitudinal direction to the outside of the module, and the contact portion 47a is bent at a right angle toward the first conductor 34 and faces the end face of the module almost in parallel. ing.

  The base end portion of the second power terminal 46 b is coupled to the connection portion 48. The second power terminal 46b protrudes from the other end side in the longitudinal direction of the first conductor 34 to the outside of the module, and its contact portion 47b is bent at a right angle toward the first conductor 34 side. And are almost parallel to each other.

  The connecting portion 48 is formed in an elongated rectangular plate shape. The connecting portion 48 is formed with a first rectangular opening 51a and a second opening 51b that are aligned for positioning. The first opening 51a is sized to fit the convex portion 45a of the first convex conductor 44a and is smaller than the main body of the first convex conductor 44a. Similarly, the second opening 51b is sized to fit the convex portion 45b of the second convex conductor 44b and is smaller than the main body of the second convex conductor 44b. A shallow rectangular recess 56 is formed on the surface of the connection portion 48 on the second conductor 36 side over a region including the first and second openings 51a and 51b. Further, the connection portion 48 integrally has three support protrusions protruding upward from the upper edge thereof. One signal terminal 50 extends upward from the middle support protrusion.

  The connecting portion 48 and the second power terminal 46b are configured so that the first and second convex conductors 44a and 44b are engaged with the first opening 51a and the second opening 51b, respectively. The second convex conductors 44a and 44b are joined.

  Furthermore, the connecting portion 48 and the convex portions 45a and 45b of the first and second convex conductors 44a and 44b are the sixth connecting body disposed in the recess 56 of the connecting portion 48, for example, a rectangular solder sheet. It is electrically and mechanically joined to the joint surface 36a of the second conductor 36 by 42d. That is, the connection member 48, the first and second convex conductors 44a, 44b, and the second conductor 34 are joined to each other by the solder sheet 42d.

  As described above, the electrodes of the first semiconductor element 38 and the second semiconductor element 40 are electrically joined to the second conductor 36 via the first convex conductors 44a and 44b. The first semiconductor element 38 and the second semiconductor element 40 are sandwiched between the first conductor 34 and the second conductor 36, parallel to the bonding surfaces 34a and 36a, and the first conductor and the second conductor. Are arranged perpendicular to the bottom surfaces 34b and 36b.

  The signal terminal 50 protrudes upward from the module and extends in parallel with the joint surface 34 a of the first conductor 34. The base ends of the four signal terminals 50 are connected to the connection terminals 38 a of the first semiconductor element 38 by bonding wires 53.

  As shown in FIGS. 2, 3, and 5, the semiconductor module 16 includes an insulating material, for example, a mold resin body (insulator) 52 that covers the above-described constituent members. The mold resin body 52 is formed in a substantially rectangular parallelepiped shape. The mold resin body 52 includes two side surfaces 52a and 52b that are parallel to the joint surfaces 23a and 36a of the first and second conductors 34 and 36, and a flat bottom surface that is orthogonal to the side surfaces 52a and 52b. 52c, an upper surface 52d facing the bottom surface 52c, and two end surfaces 52e positioned at both ends in the longitudinal direction. The bottom surface 52c is ground flat, and the bottom surfaces 34b and 36b of the first and second conductors 34 and 46 are exposed to the bottom surface 52c and are located on the same plane as the bottom surface 52c.

  The mold resin body 52 has a parting line 54 formed when the mold is removed. The parting line 54 is located in a plane including the lead frame connecting portion 48 and the first and second power terminals 46a and 46b, and remains along the upper surface 52d and both end surfaces 52e of the molded resin body 52. Further, the parting line 54 is positioned so as to be shifted to the side surface 52 b side from the center in the thickness direction W of the mold resin body 52.

  On the upper surface 52d of the mold resin body 52, a portion between the parting line 54 and the side surface 52a extends slightly inclined toward the bottom surface 52c from the parting line 54 toward the side surface 52a. The part between the two and 52b extends slightly inclined toward the bottom surface 52c from the parting line 54 toward the side surface 52b.

  In each end surface 52e of the mold resin body 52, a portion between the parting line 54 and the side surface 52a extends slightly inclined toward the other end surface from the parting line 54 toward the side surface 52a. And the side surface 52b extend slightly inclined from the parting line 54 toward the side surface 52b toward the other end surface.

  As shown in FIGS. 2, 3 and 5, the first power terminal 46a protrudes outward in the longitudinal direction of the mold resin body from one end face 52e of the mold resin body 52 at the position of the parting line 54, The contact portion 47a of the first power terminal is bent at a right angle toward the side surface 52a and faces the end surface 52e of the mold resin body 52 with a gap. Further, the contact portion 47a is positioned at the center in the thickness direction W of the mold resin body with respect to the mold resin body 52 by bending.

  The second power terminal 46b protrudes outward in the longitudinal direction of the mold resin body from one end surface 52e of the mold resin body 52 at the position of the parting line 54, and the contact portion 47b of the second power terminal 46b is formed on the side surface 52a. It is bent at a right angle to the side and faces the end surface 52e of the mold resin body 52 with a gap. Further, the contact portion 47a is positioned at the center in the thickness direction W of the mold resin body with respect to the mold resin body 52 by bending.

  The five signal terminals 50 are formed in an elongated bar shape and protrude upward from the upper surface 52 d of the mold resin body 52 at the position of the parting line 54. The five signal terminals 50 extend in parallel to each other. Further, the five signal terminals 50 are bent at two points spaced apart in the longitudinal direction, respectively, and the end portion 50 a on the extending end side of the signal terminal is located at the center in the thickness direction W of the molded resin body 52. ing. Further, the five signal terminals 50 and the first and second power terminals 46 a and 46 b are arranged symmetrically with respect to a center line located at the center in the longitudinal direction of the mold resin body 52. A conductive film (not shown) is formed on at least the outer surface of the end 50 a of the signal terminal 50.

  As shown in FIGS. 1 and 5, the semiconductor module 16 configured as described above is disposed in the installation space 22 of the support frame 14, and the bottom surface 52 c of the semiconductor module is cooled by an insulating sheet 55. 12 heat receiving surfaces 18a. As a result, the first and second conductors 34 and 36 are thermally connected to the cooler 12, and the heat generated in the first and second semiconductor elements 38 and 40 is transferred to the first and second conductors 34 and 36. The heat can be radiated to the cooler 12 via The contact portions 47a and 47b of the first and second power terminals 46a and 46b of the semiconductor module 16 are in contact with the connection terminals 24 of the bus bar 26 and are electrically connected to the bus bar 26, respectively. Further, the plurality of signal terminals 50 of the semiconductor module 16 protrude upward.

  In a plurality of semiconductor modules 16 arranged in a row, two adjacent semiconductor modules are arranged in such a manner that the side surfaces of the mold resin body 52 are adjacent to each other or in contact with each other. One of the two adjacent semiconductor modules 16 may be arranged in a direction inverted by 180 degrees with respect to the other. Regardless of the orientation, the first and second power terminals 46 a and 46 b of the semiconductor module are reliably engaged with the connection terminal 24 of the bus bar 26. Also in this case, in any orientation, the signal terminal 50 of the semiconductor module 16 is located at the center of the mold resin body 52 in the thickness direction and is located at a predetermined position with respect to the control circuit board 32. The

  By installing the control circuit board on the semiconductor module 16, the end of the signal terminal 50 of each semiconductor module 16 is inserted into a through hole formed in the control circuit board, and the control circuit board is electrically connected to the control circuit board by solder or the like (not shown). Connected.

  Next, the manufacturing method of the semiconductor module 16 which comprises the semiconductor power converter device mentioned above is demonstrated. 6 to 21 are perspective views respectively showing the manufacturing process of the semiconductor module. In this embodiment, after manufacturing two semiconductor modules together, it cut | disconnects and isolate | separates into two semiconductor modules. At that time, the bottom surface of the semiconductor module is simultaneously formed by cutting.

  As shown in FIG. 6, for example, a first fixing jig 60 formed of SUS is prepared, and the first conductor 34 is mounted and positioned in the positioning recess 60 c of the first fixing jig. At this time, the first conductor 34 is loaded into the first fixing jig 60 so that the joint surface 34a of the first conductor 34 faces upward. Here, the 1st conductor 34 is formed in the magnitude | size for two modules, ie, twice the magnitude | size. The joining surface 34a has a first region 35a on one side and a second region 35b on the opposite side with the center line C of the first conductor 34 as a boundary.

  The first fixing jig 60 has a rectangular bottom wall and a peripheral wall 60b erected along the periphery of the bottom wall 60a, and is formed in a rectangular box shape. A rectangular positioning recess 60c having a size corresponding to the first conductor 34 is formed in the bottom wall 60a. A through hole 60g is formed in the center of the recess 60c. When releasing the mold, the eject pin is inserted into the through hole 60g, and the first conductor 34 is pushed up and removed from the first fixing jig 60. In addition, two recesses 60d are formed in the peripheral wall 60b, and are located on both sides in the longitudinal direction of the positioning recess 60c.

  Next, as shown in FIG. 7, for example, an elongated rectangular plate-shaped split jig 62 formed of SUS is placed on the bonding surface 34 a of the first conductor 34, and both ends of the split jig 62 are placed. The part is placed in the recess 60d of the first fixing jig 60 and positioned.

  The split jig 62 includes a rectangular first opening 63a for positioning the first semiconductor element relative to the first conductor 34, a rectangular second opening 63b for positioning the second semiconductor element, and The rectangular third opening 63c for positioning the proximal end portion of the first power terminal 46a is provided, and these openings are located on the first region 35a of the bonding surface 34a. The split jig 62 includes a rectangular fourth opening 63d for positioning the third semiconductor element with respect to the first conductor 34, and a rectangular fifth opening 63e for positioning the fourth semiconductor element. , And a rectangular sixth opening 63f for positioning the base end portion of the first power terminal 46a, and these openings are located on the first region 35b of the joint surface 34a. The split jig 62 is divided into two parts, a first split part 62a and a second split part 62b, along a center line passing through the first to third openings. And the 1st division part 62a and the 2nd division part 62b are detachable to the 1st fixing jig 60 each independently.

  Subsequently, as shown in FIG. 8, a first connection body, for example, a rectangular solder, is formed on the first region 35 a of the bonding surface 34 a of the first conductor 34 in the first opening 63 a of the split jig 62. The sheet 42a is placed. In addition, a second connection body, for example, a rectangular solder sheet 42b, is placed on the first region 35a of the bonding surface 34a of the first conductor 34 in the second opening 63b of the split jig 62. A third connector, for example, a rectangular solder sheet 42c, is placed on the second region 35b of the joint surface 34a of the first conductor 34 in the fourth opening 63d of the split jig 62. In addition, a fourth connection body, for example, a rectangular solder sheet 42 d is placed on the second region 35 b in the fifth opening 63 f of the split jig 62. The solder sheets 42a, 42b, 42c, 42d and a plurality of solder sheets to be described later each include a plurality of, for example, three or more particles. By containing particles having a predetermined diameter, the height of the joint portion does not become less than the particle diameter even after solder melting and solidification. The particles are formed of a material having a melting temperature higher than the melting temperature of the solder. Further, the particles need to have a hardness that does not cause significant deformation due to the second conductor and the weight, and preferably have the same diameter as the designed joint height.

  Next, as shown in FIG. 9, the first semiconductor element 38 is placed on the solder sheet 42 a in the first opening 63 a of the split jig 62. At this time, the first semiconductor element 38 is placed in parallel with the bonding surface 34a of the first conductor 34 so that one electrode of the first semiconductor element 38 is positioned on the solder sheet 42a. At the same time, the first semiconductor element 38 is disposed in the first opening 63 a, and the first semiconductor element 38 is positioned with respect to the first conductor 34 by the split jig 62. The second semiconductor element 40 is placed on the solder sheet 42 b in the second opening 63 b of the split jig 62. At this time, the second semiconductor element 40 is placed in parallel with the bonding surface 34a of the first conductor 34 so that one electrode of the second semiconductor element 40 is positioned on the solder sheet 42b. At the same time, the second semiconductor element 40 is disposed in the second opening 63 b and the second semiconductor element 40 is positioned with respect to the first conductor 34.

  In addition, the third semiconductor element 38 b (corresponding to the first semiconductor element (IGBT) of the semiconductor module) is placed on the solder sheet 42 c in the fourth opening 63 d of the split jig 62. At this time, the third semiconductor element 38b is placed in parallel with the bonding surface 34a of the first conductor 34 so that one electrode of the third semiconductor element 38b is positioned on the solder sheet 42c. At the same time, the third semiconductor element 38 b is disposed in the fourth opening 63 d, and the third semiconductor element 38 b is positioned with respect to the first conductor 34 by the split jig 62. The fourth semiconductor element 40b (corresponding to the second semiconductor element (diode) of the semiconductor module) is placed on the solder sheet 42d in the fifth opening 63e of the split jig 62. At this time, the fourth semiconductor element 40b is placed in parallel with the bonding surface 34a of the first conductor 34 so that one electrode of the fourth semiconductor element 40b is positioned on the solder sheet 42d. At the same time, the fourth semiconductor element 40b is disposed in the fifth opening 63e, and the fourth semiconductor element 40b is positioned with respect to the first conductor 34. The third and fourth semiconductor elements 38b and 40b are arranged at positions symmetrical to the first and second semiconductor elements 38 and 40 with respect to the center line C of the first conductor 34.

  Subsequently, as shown in FIG. 10, a rectangular solder sheet 42 e as a fifth connection body is placed on the electrode of the first semiconductor element 38 in the first opening 63 a of the split jig 62, A rectangular solder sheet 42f is placed as a sixth connector on the electrode of the second semiconductor element 40 in the two openings 63b. Furthermore, a rectangular solder sheet 42g is placed as a seventh connector on the joint surface 34a of the first conductor 34 in the third opening 63c of the split jig 62. Similarly, a rectangular solder sheet 42h is placed as an eighth connection body on the electrode of the third semiconductor element 38b in the fourth opening 63d of the split jig 62, and the fourth opening is formed in the fifth opening 63e. A rectangular solder sheet 42i is placed on the electrode of the semiconductor element 40b as a ninth connection body. Further, a rectangular solder sheet 42j is placed as a tenth connection body on the joint surface 34a of the first conductor 34 in the sixth opening 63f of the split jig 62. The solder sheets 42e to 42k each include a plurality of, for example, three or more particles having a predetermined diameter.

  Next, as shown in FIG. 11, the first convex conductor 44 a is placed on the solder sheet 42 e in the first opening 63 a of the split jig 62. At this time, the first convex conductor 44a is placed so that the flat main surface side of the main body is positioned on the solder sheet 42c, and the upper portion of the main body and the convex portion 45a are separated from the first opening 63a. Projecting upward beyond the surface of 62.

  The second convex conductor 44b is placed on the solder sheet 42f in the second opening 63b of the split jig 62. The second convex conductor 44b is placed so that the flat main surface side of the main body is positioned on the solder sheet 42d, and the upper portion of the main body and the convex portion 45b extend from the second opening 63b to the upper surface of the split jig 62. Projecting upwards beyond.

  Similarly, the third convex conductor 44c (corresponding to the first convex conductor of the semiconductor module) is placed on the solder sheet 42h in the fourth opening 63d of the split jig 62. The third convex conductor 44c is placed so that the flat main surface side of the main body is positioned on the solder sheet 42h, and the upper portion of the main body and the convex portion 45c extend from the fourth opening 63d to the surface of the split jig 62. Projecting upwards beyond. A fourth convex conductor 44d (corresponding to the second convex conductor of the semiconductor module) is placed on the solder sheet 42i in the fifth opening 63e of the split jig 62. The fourth convex conductor 44d is placed so that the flat main surface side of the main body is positioned on the solder sheet 42g, and the upper portion of the main body and the convex portion 45d extend from the fifth opening 63e to the upper surface of the split jig 62. Projecting upwards beyond. The first to fourth convex conductors are formed by pressing a metal block.

  Subsequently, the lead frame 70 made of a conductive metal plate is placed on the first fixing jig 60 and on the first to fourth convex conductors 44a to 44d. As shown in FIG. 18, the lead frame 70 integrally has a rectangular frame 70a, two sets of power terminals connected to and supported by the frame, two sets of signal terminals, and two connections. doing. That is, the first power terminal 46a extending inward from one side of the frame 70a, the second power terminal 46b extending inward from the other side of the frame, and the first power terminal from the second power terminal Two rectangular connection portions 48 extending toward the outside and five signal terminals 50 extending outward and inward from the other side portions of the frame body are provided. The frame 70a is provided with a plurality of pin holes 71 through which positioning pins can be inserted. The lead frame 70 is formed symmetrically with respect to the center line C.

  Each connection portion 48 is formed with a rectangular first opening 51a and second opening 51b side by side. A shallow rectangular recess 56 is formed on the surface of the connection portion 48 on the second conductor 36 side over a region including the first and second openings 51a and 51b. Further, the front end portion of the first power terminal 46a is bent downward by a press or the like, and is connected to the connection portion 48 by a height corresponding to the thickness of the first semiconductor element 38 and the first convex conductor 44a. Is also shifted to the first conductor 34 side.

  As shown in FIG. 12, the frame body 70 a of the lead frame 70 is arranged on the step portion of the peripheral wall 60 b of the first fixing jig 60, and the lead frame 70 is positioned at a predetermined position with respect to the first fixing jig 60. . One connecting portion 48 of the lead frame 70 is placed on the first and second convex conductors 44a and 44b. At this time, the upper surfaces of the main bodies of the first and second convex conductors 44a and 44b abut against the lower surface of the connecting portion 48, and the convex portions 45a and 45b are the first opening 51a and the second opening 51b of the connecting portion 48. Engage in. As a result, the first and second convex conductors 44 a and 44 b are positioned at predetermined positions with respect to the connection portion 48. Further, the convex portions 45 a and 45 b are located exposed on the surface of the connection portion 48, particularly on the bottom surface of the recess 56. On the other hand, the tip of the first power terminal 46a is placed on the solder sheet 42g on the bonding surface 34a.

The other connecting portion 48 of the lead frame 70 is placed on the third and fourth convex conductors 44c and 44d. At this time, the upper surfaces of the main bodies of the third and fourth convex conductors 44c and 44d are in contact with the lower surface of the connecting portion 48, and the convex portions 45c and 45d are the first opening 51a and the second opening 51b of the connecting portion 48. Engage in. As a result, the third and fourth convex conductors 44 c and 44 d are positioned at predetermined positions with respect to the connection portion 48. The convex portions 45 c and 45 d are located exposed on the surface of the connection portion 48, particularly on the bottom surface of the recess 56. The tip of the other first power terminal 46a is placed on the solder sheet 42j on the joint surface 34a.
The lead frame 70 may be divided into two frame bodies 70a along the center line C, and two independent lead frames (first lead frame and second lead frame) may be used.

  Subsequently, as illustrated in FIG. 13, an elongated rectangular solder sheet 42 k is placed as a connection body in the recess 56 of each connection portion 48. The solder sheet 42k is placed on the convex portions 45a and 45b of the first and second convex conductors 44a and 44b and on the connection portion 48. The other solder sheet 42k is placed on the convex portions 45c and 45d of the third and fourth convex conductors 44c and 44d and on the connection portion 48.

As shown in FIGS. 14 and 15, the second conductor 36 is placed on the solder sheet 42 k and the two connection portions 48, and the second fixing jig is placed around the second conductor 36 and on the lead frame 70. 80 is placed. Here, the second conductor 36 is formed to have a size equivalent to two semiconductor modules, that is, approximately twice as large. The bonding surface 36 a is disposed so as to face the first conductor 34. The second fixing jig 80 is formed, for example, by SUS into a rectangular plate having a size substantially equal to that of the first fixing jig 60, and a rectangular positioning opening 80a to which the second conductor 36 can be attached. have. The second fixing jig 80 is placed on the lead frame 70 while being positioned at a predetermined position with respect to the first fixing jig 60 by engaging the peripheral edge of the peripheral wall step portion of the first fixing jig 60. Placed. Thereby, the second fixing jig 80 presses the lead frame 70 from above and holds the lead frame 70 in a predetermined position. The second conductor 36 is engaged with the positioning opening 80 a of the second fixing jig 80 and is positioned at a predetermined position with respect to the lead frame 70.
Alternatively, after the second fixing jig 80 is attached to the first fixing jig 60, the third conductor 36 may be attached to the positioning opening 80a of the second fixing jig 80.

  Next, as shown in FIG. 16, a rectangular plate-shaped weight 82 is placed on the second fixing jig 80 and the second conductor 36. The plurality of members described above are pressed in the stacking direction by the weight 82 to fix the position. For the weight 82, a weight weight at which the joint height is substantially equal to the particle size in the solder is selected.

  The component members and the first and second fixing jigs 60 and 80 stacked and positioned as described above are heated for a predetermined time in a reflow furnace, for example, and the solder sheets 42a to 42k are collectively melted and then cooled. The constituent members are joined by solidifying the solder. At the time of joining with solder, the solder sheet 42k is disposed in the recess 56 of the connection portion 48, so that it does not flow out of the recess 56 at the time of melting, and a predetermined position of the constituent members can be joined. . Also, the solder sheet 42k melts to join the connection portion 48, the convex portions 45a and 45b of the first and second convex conductors, and the second conductor 36 to each other. Similarly, the other solder sheet 42k is melted to join the connection portion 48, the convex portions 45c and 45d of the third and fourth convex conductors, and the second conductor 36 to each other. .

  After the solder sheet is melted and solidified as described above, as shown in FIG. 17, the weight 82, the first and second fixing jigs 60 and 80, and the split type jig are joined from the joined component and lead frame 70. Remove the tool 62. Subsequently, after visual inspection of the joined components and the lead frame 70 is performed, as shown in FIG. 18, the base ends of the signal terminals 50 and the corresponding connection terminals 38a of the first semiconductor element 38 are bonded by wire bonding. Are connected by a bonding wire (conductive wire) 53. Further, the base end of each signal terminal 50 and the corresponding connection terminal 38a of the third semiconductor element 38b are connected by a bonding wire (conductive wire) 53 by wire bonding.

After wire bonding, an appearance inspection, for example, inspection of whether wire unbonding has occurred or whether the wire loop shape has been crushed is performed.
Next, as shown in FIG. 19, all components except the frame body 70 a of the lead frame 70, the end portions of the first and second power terminals 46 a and 46 b, and the extending portion of the signal terminal 50 are insulated. The material is covered with a resin, for example, resin, and a substantially rectangular parallelepiped molded resin body 52 is formed. Such a mold resin body 52 is molded by placing the above-mentioned laminated laminate in a mold and injecting a synthetic resin into the mold. The molding die is released with the lead frame 70 as a ridge, and a parting line 54 that is located in the same plane as the lead frame 70 is formed in the mold resin body 52.

Subsequently, as shown in FIGS. 20 and 21, the mold resin body 52, the first conductor 34, the second conductor 36, and the frame body 70 a of the lead frame 70 are connected to the center line C ( The first module 16a including the first and second semiconductor elements 38 and 40 and the second module 16b including the third and fourth semiconductor elements 38b and 40b are separated. For example, a rotating blade 84 is used for cutting. By cutting, the bottom surface of the first module 16a where the first and second conductors 34 and 36 are exposed and the bottom surface of the second module 16b where the first and second conductors are exposed are formed simultaneously.
The cutting is not limited to a blade, and a laser, a water jet, or the like may be used.

  Subsequently, for each of the first and second modules 16a and 16b, the lead frame 70 is cut at a predetermined position and separated from the mold resin body 52, and the five signal terminals 50 and the first and second power terminals 46a are separated. , 46b.

Thereafter, the contact portions 47a and 47b of the first and second power terminals 46a and 46b are bent at a right angle, and each signal terminal 50 is bent and formed at two locations. Finally, a conductive film is formed on the surface of each signal terminal 50.
Through the above steps, two semiconductor modules 16 of the power conversion device are completed.

  According to the method of manufacturing a semiconductor power conversion device configured as described above, a plurality of semiconductor elements are arranged on a conductor so as to form a pair and sealed with an insulator, and then the paired semiconductor device is separated. Thus, the conductor and the insulator are cut so that the conductor is exposed to the bottom surface of the module. According to this manufacturing method, the conductor and the insulator are flush with each other after cutting, and the conductor can be exposed only by cutting. This eliminates the need to grind the bottom surface and simplifies the manufacturing process. Further, the exposure of the conductor by cutting does not depend on the dimensions and flatness of the conductor and the assembly accuracy, and therefore, it is possible to manufacture using a low-cost member and general-purpose equipment.

  Since the material loss is only the thickness (width) of the blade to be cut, the material efficiency is improved by using a thin blade. The workpiece can be accurately conveyed to the processing point using a pin hole provided in the lead frame as a guide, and cutting can be performed simply by pressing and fixing the workpiece from above. Thereby, a manufacturing process can be simplified. Furthermore, in the case of cutting, the processing time can be shortened compared to grinding, and the manufacturing process time can be shortened. Two semiconductor modules can be manufactured using a single first conductor, second conductor, and lead frame, and the number of parts and man-hours can be reduced. Moreover, the number of parts can be reduced by making the power terminal, the signal terminal, and the connection part into an integral part (lead frame). At the same time, compared with the case where the power terminal and the signal terminal are separate parts, the mounting position accuracy of the power terminal and the signal terminal is excellent, and the dimensional variation of the finished product is reduced.

By containing a plurality of particles in the solder as the connection body, it is possible to control so that the height of the joint portion does not become the particle or less even after the solder is melted and solidified. Thereby, it is possible to reduce the variation in the height dimension of the joint and improve the assembly accuracy. Further, by mounting a weight on the second conductor at the time of joining, floating of the second conductor due to the surface tension of the solder is suppressed, and variation in the height dimension of the joint is reduced. At the same time, by applying a load to the component part with the weight, it is possible to prevent the positional deviation of the part at the time of joining.
From the above, it is possible to obtain a method for manufacturing a power semiconductor device that is simple, has high material efficiency, and can manufacture a semiconductor device at low cost.

  Next, a method for manufacturing a power semiconductor device according to another embodiment will be described. In other embodiments to be described below, the same parts as those in the first embodiment described above are denoted by the same reference numerals, detailed description thereof is omitted, and different parts will be mainly described.

(Second Embodiment)
FIG. 22 shows a manufacturing process by the manufacturing method according to the second embodiment. According to the present embodiment, when the component including the first and second conductors is covered with the mold resin, the region 73 having a predetermined width along the center line C of the first conductor is removed as shown in FIG. Then, the component parts are covered with the mold resin, and the mold resin bodies 52 are formed on both sides of the region 73. Part of the first and second conductors is exposed in the region 73.

Subsequently, the first conductor 34, the second conductor 36, and the frame body 70a of the lead frame 70 are cut along the center line C (cut line) of the first conductor 34, and the first module 16a, Separated into the second module 16b. At this time, the first and second conductors are cut at the portions of the first and second conductors exposed from the mold resin body 52 to the region 73. For example, a rotating blade 84 is used for cutting. By cutting, the bottom surface of the first module 16a where the first and second conductors 34 and 36 are exposed and the bottom surface of the second module 16b where the first and second conductors are exposed are formed simultaneously.
The cutting is not limited to a blade, and a laser, a water jet, or the like may be used. In the manufacturing method according to the second embodiment, other manufacturing steps are the same as those in the first embodiment described above.

  According to the manufacturing method according to the second embodiment as described above, by filling the insulating material (mold resin) except for the cutting region, the filling amount of the insulating material is reduced, and the manufacturing cost is reduced. Can do. In addition, also in 2nd Embodiment, the effect similar to 1st Embodiment can be acquired.

Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. Various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiments. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.
For example, the dimensions, shapes, and the like of the components of the power conversion device are not limited to the above-described embodiments, and can be variously changed according to the design.

DESCRIPTION OF SYMBOLS 10 ... Semiconductor power converter device, 12 ... Cooler, 14 ... Support frame,
16 ... Semiconductor module, 18 ... Cooling block, 18a ... Heat receiving surface, 24 ... Connection terminal,
32 ... Control circuit board, 34 ... First conductor, 34a ... Bonding surface, 34b ... Bottom surface,
36 ... 2nd conductor, 36a ... Bonding surface, 36b ... Bottom surface, 38 ... 1st semiconductor element,
40 ... 2nd semiconductor element, 38b ... 3rd semiconductor element, 40b ... 4th semiconductor element,
44a ... first convex conductor, 44b ... second convex conductor, 44c ... third convex conductor,
44d ... fourth convex conductor, 46a ... first power terminal, 46b ... second power terminal,
48 ... Connection portion, 50 ... Signal terminal, 52 ... Mold resin body, 60 ... First fixing jig,
62 ... Split jig, 70 ... Lead frame, 80 ... Second fixing jig

Claims (6)

On the first bonding surface of the first conductor, plate-like first semiconductor elements and second semiconductor elements each having different electrodes on the front and back surfaces in the first region on one side of the center line of the first conductor, One electrode is joined so as to contact the first joining surface,
On the first bonding surface of the first conductor, plate-like third semiconductor elements and fourth semiconductor elements each having different electrodes on the front and back surfaces in the second region opposite to the center line, respectively, Bonding so that the electrode contacts the first bonding surface,
Bonding a spacer made of a conductor on each electrode of the first to fourth semiconductor elements,
The connecting portion of the lead frame having two sets of power terminals, two sets of signal terminals, and two sets of connecting portions is connected to the spacers on the first and second semiconductor elements, and on the third and fourth semiconductor elements. Bonding to each of the spacers,
Joining one of the set of power terminals to the first region of the first conductor;
Joining one of the other set of power terminals to the second region of the first conductor;
A second conductor having a second bonding surface is bonded onto the two sets of island connection portions such that the second bonding surface faces the first bonding surface of the first conductor;
Connecting the electrode of the first semiconductor element and a set of signal terminals with a conducting wire;
Connecting the electrode of the third semiconductor element and another set of signal terminals with a conductive wire;
An end of the two sets of electrode terminals, an end of the two sets of signal terminals, and the first conductor and the second conductor are covered with an insulating material to form an insulator,
Cutting the insulator, the first conductor, and the second conductor along a center line of the first conductor; and a first module including the first and second semiconductor elements; and the third and second Separated into a second module containing four semiconductor elements,
A method of manufacturing a semiconductor power conversion device, wherein the island connection portion, the power terminal, and the signal terminal of the lead frame are left, and other portions of the lead frame are cut off.   The bottom surface of the first module from which the first and second conductors are exposed and the bottom surface of the second module from which the first and second conductors are exposed are formed simultaneously by the cutting. A manufacturing method of the semiconductor power conversion device according to 1.   The method for manufacturing a semiconductor power conversion device according to claim 1, wherein the semiconductor power conversion device is cut by any one of a blade, a laser, and a water jet. The insulator is formed by covering the first and second semiconductors with an insulating material except for a part of the first and second semiconductors along a center line of the first semiconductor,
4. The semiconductor according to claim 1, wherein the cutting is performed by cutting a region of the first and second conductors exposed from the insulating material along the center line. 5. A method for manufacturing a power converter.   The lead frame has a frame body that connects the two sets of power terminals, two sets of signal terminals, and two connection portions, and the frame body is cut by the cutting. 5. A method for manufacturing a semiconductor power conversion device according to claim 4.   The lead frame includes a first lead frame having a set of power terminals, a set of signal terminals, and a connection portion, and a second lead frame having a set of power terminals, a set of signal terminals, and a connection portion. The first lead frame is joined to the first and second semiconductor elements, and the second lead frame is joined to the third and fourth semiconductor elements. Item 6. A method for manufacturing a semiconductor power conversion device according to Item 1 to 5.

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