JP4129027B2 - Semiconductor device - Google Patents

Description

  The present invention relates to a semiconductor device such as a power module mounted on a moving body such as a car.

  As an in-vehicle semiconductor device, a leaf spring is disposed on a semiconductor module disposed on the upper surface of a heat sink, and a reinforcing beam for reinforcing the leaf spring is disposed on the leaf spring, and a leaf spring is disposed on the back surface of the reinforcing beam. A technique is disclosed in which a protrusion that protrudes toward the heat sink is provided, and a tightening load when the reinforcing beam is tightened to the heat sink side with a screw is transmitted from the reinforcing beam to a desired position of the leaf spring (for example, Patent Documents). 1).

Japanese Patent Laying-Open No. 2005-235992

In the prior art, a plurality of protrusions for transmitting a tightening load by a screw are provided on the back side of the reinforcing beam, but the protrusions have a uniform protrusion amount. Both ends in the longitudinal direction of the reinforcing beam are in the form of cantilever beams outside the screws for fixing the reinforcing beam, are easily deformed, and cannot transmit the tightening load sufficiently. There was a problem that the force was insufficient in the cantilever part.
In addition, when a semiconductor module is placed on a thin heat sink or heat sink, the rigidity of the heat sink or heat sink decreases, so the heat sink is deformed by the pressing force generated by the leaf spring and the reinforcing beam, and the semiconductor module The pressure contact with the heat sink cannot be secured. Especially, the outside of the screw that fixes the semiconductor module arranged on the outermost side is a cantilever as well as the reinforcing beam. There is a problem that it is difficult to secure the pressure contact force between the semiconductor module and the heat sink or the heat sink.

The present invention has been made to solve the above-described problems, and aims to improve the lack of pressure contact between the semiconductor module and the heat sink or the heat sink at both longitudinal ends of the reinforcing beam. .

  The semiconductor device according to the present invention includes a semiconductor module in which a semiconductor element is resin-sealed and a screw through hole is provided at the center, a pressing plate spring disposed on the upper surface side of the semiconductor module, and the pressing plate shape A reinforcing beam arranged on a spring to reinforce the holding plate spring; a heat sink or a heat sink arranged on the back side of the semiconductor module; and the semiconductor module includes the reinforcing beam and the presser from the reinforcing beam side. It is fixed to the heat sink side or the heat radiating plate side by a screw inserted into the screw through hole of the semiconductor module through a plate spring for use, and the reinforcing beam is arranged on the back side in contact with the plate spring for holding A plurality of protrusions for transmitting a tightening load by a screw to the presser plate spring, and the protrusions positioned at the longitudinal ends of the reinforcing beams are Is located near the center of the direction is characterized in that the projecting amount than the projection is large.

  The semiconductor device according to the present invention includes a semiconductor module in which a semiconductor element is resin-sealed and a screw through hole is provided in the center, a plate spring for pressing disposed on the upper surface side of the semiconductor module, and the pressing A reinforcing beam disposed on the plate spring to reinforce the pressing plate spring; a heat sink or a heat sink disposed on the back side of the semiconductor module; and the semiconductor module includes the reinforcing beam from the reinforcing beam side. It is fixed to the heat sink side or the heat radiating plate side by a screw inserted into the screw through hole of the semiconductor module via the pressing plate spring, and both longitudinal ends of the reinforcing beam are connected to the heat sink side or the heat radiating plate. It is characterized by being fastened to the side.

  According to the semiconductor device of the present invention, since the protrusion amount of the protrusion disposed at the portion that becomes the cantilever at the longitudinal end portion of the reinforcing beam is configured to be larger than the protrusion disposed closer to the center in the longitudinal direction, There is an effect that it is possible to secure the pressure contact force between the semiconductor module and the heat sink or the heat sink at the end.

  Also, according to the semiconductor device of the present invention, the end of the reinforcing beam in the longitudinal direction is fastened and fixed to the heat sink side or the heat sink by screws, so the end of the reinforcing beam does not become a cantilever, but the semiconductor module and the heat sink Alternatively, there is an effect that it is possible to ensure the pressure contact force with the heat sink.

Embodiment 1 FIG.
1 is an exploded perspective view showing a semiconductor device according to Embodiment 1 of the present invention, and FIG. 2 is a side view showing a reinforcing beam 94 used in Embodiment 1 of the present invention. The semiconductor device according to the first embodiment has basically the same structure as the semiconductor device disclosed in Japanese Patent Application Laid-Open No. 2005-235992 filed by the same applicant, but the shape of the reinforcing beam 94 is different. The reinforcing beam 94 according to the first embodiment is provided on the back side of the reinforcing beam longitudinal direction end portion (shown in FIG. 2 is the both end portions) serving as a cantilever (on the side of the pressing plate spring 71 described later). The protrusion 17 to be arranged is characterized in that the protruding amount is larger than that of the protrusion 15 arranged near the center of the reinforcing beam 94. In FIGS. 1 and 2, both ends in the longitudinal direction of the reinforcing beam 94 are cantilever beams, but it goes without saying that only one side may be a cantilever beam.

  First, the basic structure of the semiconductor device in FIG. 1 will be described. In FIG. 1, a plurality of semiconductor modules 1 in which semiconductor elements are sealed with resin (three in the example of FIG. 1) are juxtaposed on a heat sink 2. Each semiconductor module 1 is provided with a power connection terminal 3, an output terminal 4, and a screw through hole 5 provided at the center. Although not shown in FIG. 1, the signal terminal protrudes from the side surface of the semiconductor module 1 as in FIG. 3 described later. The heat sink 2 is provided with a screw hole 6 at a position corresponding to the screw through hole 5 of each semiconductor module 1.

  A plate spring 71 having a pentroof-shaped cross-section in common with each semiconductor module 1 is disposed on the surface opposite to the heat sink 2 of each semiconductor module 1 (the upper surface side of the semiconductor module 1), A screw through hole 8 is provided at a position corresponding to the screw through hole 5 of the semiconductor module 1. A slit (notch) 14 is formed in the presser plate spring 71 corresponding to the position along the boundary between the adjacent semiconductor modules 1. When the slit 14 is provided in the holding plate spring 71, the semiconductor module 1 is inserted into the screw through hole 5 of the semiconductor module 1 through the reinforcing beam 94 and the holding plate spring 71 from the reinforcing beam 94 side. When the screw 11 is fixed to the heat sink 2 side, the tightening force of the screw 11 is distributed for each semiconductor module 1. As a result, even if there is only one pressing plate-like spring 71, the holding load is independent for each semiconductor module 1, so even if there is a variation in the height dimension of each semiconductor module 1, this is absorbed. can do.

  Needless to say, a plurality of semiconductor modules 1 are individually separated, but even if the semiconductor module 1 is a single unit that is not divided, the pressing plate spring 71 is provided with a slit 14. The tightening force of the screw 11 is distributed to each part of the semiconductor module 1, and a considerable effect can be expected for uniform load.

  The reinforcing beam 94 that reinforces the presser plate spring 71 is disposed at the center of the presser plate spring 71 along the longitudinal direction of the presser plate spring 71. The reinforcing beam 94 is also provided with a screw through hole 10 at a position corresponding to the screw through hole 5 of each semiconductor module 1, and on the side of the pressing plate spring 71 (back surface side) of the reinforcing beam 94, the semiconductor modules 1 are connected to each other. In order to generate (transmit) a load at the boundary portion of the semiconductor module 1, a protrusion 15 is provided at a position corresponding to the boundary portion between the semiconductor modules 1. The protrusions 15 and the protrusions 17 disposed at both ends of the reinforcing beam are provided on both sides of the screw through hole 10. By providing the protrusions 15 and 17 on the reinforcing beam 94, it is possible to compensate for the load of the portion where the pressing load of the semiconductor module 1 is insufficient.

  Further, by optimizing the height dimension and position of the protrusions 15 and 17, variations in the height dimension of each semiconductor module 1 can be absorbed. This is due to the fact that the projections 15 and 17 are added to the desired position of the reinforcing beam 94 and the spring effect of the reinforcing beam 94. Needless to say, a plurality of semiconductor modules 1 are individually separated, but projections 15 and 17 are added to the reinforcing beam 94 at desired positions even when the semiconductor module 1 is not divided. By doing so, the tightening force of the screw 11 is dispersed in a desired portion of the semiconductor module 1, and a considerable effect can be expected for the equalization of the load. Furthermore, the use of the reinforcing beam 94 provided with the protrusions 15 and 17 together with the pressing plate-like spring 71 provided with the slit 14 in the first embodiment makes the fixing of the semiconductor module 1 more stable.

  These assemblies are performed by placing each semiconductor module 1, the holding plate spring 71, and the reinforcing beam 94 on the heat sink 2 by aligning the screw holes 6 and the screw through holes 5, 8, 10. Each semiconductor module 1 is fixed to the heat sink 2 by tightening to a desired load with screws 11. At this time, the tightening force of the screw 11 is dispersed by the deflection of the presser plate spring 71, and a desired uniform load can be applied to each semiconductor module 1 when the presser plate spring 71 is fully compressed. it can. This is due to the fact that the cross-sectional shape of the holding plate spring 71 is a pent roof type. Further, by using the reinforcing beam 94, the bending rigidity of the pressing plate spring 71 can be supplemented, and the pressing plate spring 71 can be pressed more uniformly against each semiconductor module 1.

With such a configuration, a desired uniform load can be applied to each semiconductor module 1, and the thermal resistance between the semiconductor module 1 and the heat sink 2 can be lowered and stabilized.

  Furthermore, as described above, as a feature of the semiconductor device according to the first embodiment, the protrusions 15 and 17 as shown in FIG. The protrusions 17 provided at both ends in the longitudinal direction that become cantilever beams by tightening the reinforcing beam 94 with the screw 11 have a larger protrusion amount than the protrusions 15 provided closer to the center. 1 and 2 suggest that the protrusions 15 and 17 are columnar protrusions, but the present invention is not limited to this shape. For example, the reinforcing beam 94 is partially bent. It is also possible to form the protrusion 15 or 17 by forming a protrusion on the back surface side and adjusting the protrusion amount. Any protrusion can be used in the present invention as long as it has a shape capable of transmitting the tightening load by the screw 11 from the reinforcing beam 94 to the pressing plate spring 71.

  When all the protrusions of the reinforcing beam have the same protruding amount as in the conventional structure, both ends of the reinforcing beam (the ends of the reinforcing beam positioned outside the screws for fixing the semiconductor module disposed on the outermost side). However, in the semiconductor device according to the first embodiment, the reinforcing beam to be a cantilever is easily deformed because it is in a cantilever state. By projecting the protrusions 17 disposed on the back surfaces of both end portions of 94 from the protrusions 15 disposed closer to the center of the reinforcing beam 94, the amount of deformation at both ends of the reinforcing beam 94 can be positively increased when tightening with the screw 11. By increasing the size, it is possible to transmit a pressing force equivalent to that of the other projections 15 arranged near the center of the reinforcing beam that is not a cantilever beam.

As described above, the heat resistance between the semiconductor module 1 and the heat sink 2 can be stabilized at a low level by transmitting the tightening load by the screw 11 of the reinforcing beam 94 evenly to the holding plate spring 71 side.
In the above example, the configuration in which the semiconductor module 1 is mounted on the heat sink 2 is shown. However, instead of the heat sink 2, a structure using a heat radiating plate having the same rigidity may be used as the protrusion 17 on the reinforcing beam 94. It is also possible to apply a structure in which

Embodiment 2. FIG.
3 is an exploded perspective view showing a semiconductor device according to Embodiment 2 of the present invention. As shown in FIG. 3, the power supply connection terminal 3 and the output terminal 4 protrude from the side surface portion of the semiconductor module 1, and a plurality of signal terminals 41 protrude continuously. The semiconductor device according to the second embodiment has basically the same configuration as the semiconductor device disclosed in Japanese Patent Application Laid-Open No. 2005-235990 filed by the same applicant, but the semiconductor device is reduced in size and thickness. In order to reduce weight and cost, a plate-like heat sink 21 is used as a member to replace the heat sink 2, and a reinforcing beam 95 having screw through holes 30 provided at both ends is used as a reinforcing beam. The difference is that the reinforcing beam 95 has a structure in which the reinforcing beam 95 is fastened to the screw hole 22 provided in the heat radiating plate 21 by the screw 18 via the spacer 19. Although not shown, a flexible heat conducting member such as paste grease or sheet having thermal conductivity is disposed between the semiconductor module 1 and the heat sink 21 to reduce thermal resistance. is doing.

  In order to reduce the thermal resistance, when a flexible heat conductive member such as paste grease or sheet having heat conductivity is disposed between the semiconductor module 1 and the heat sink 2 or the heat sink 21, the semiconductor module 1 and It is necessary to configure the heat conduction member to be as thin as possible by pressing the heat sink 2 or the heat sink 21 with a considerable force.

  However, in the case where both ends of the reinforcing beam are not fastened to the heat sink as in the semiconductor device disclosed in Japanese Patent Laid-Open No. 2005-23592, the heat sink 2 is used to reduce the size, thickness, weight, and cost. If the plate-like heat sink 21 is used instead, since the bending rigidity of the heat sink 21 is low, the heat sink 21 is deformed by the force of pressing the semiconductor module 1, and the pressure contact force between the semiconductor module 1 and the heat sink 21 can be secured. There was a problem of disappearing. In particular, the heat radiating plate 21 is in a cantilever state in which both ends in the longitudinal direction of the reinforcing beam are screws 11 as fulcrums on the outer side of the screw 11 that fixes the semiconductor module 1 disposed on the outermost side, and is easily deformed. In addition, since the reinforcing beam itself is easily deformed, it is difficult to ensure the pressure contact force between the semiconductor module 1 and the heat sink 21. As a result, there is a problem that the thermal resistance between the semiconductor module 1 and the heat sink 21 is high and unstable.

  Therefore, in the second embodiment, a reinforcing beam 95 having screw through holes 30 provided at both ends thereof is used. The reinforcing beam 95 is made of a spacer 19 (the height of the spacer 19 is substantially equivalent to the thickness of the semiconductor module 1 and the pressing plate spring 71, and is a cylindrical member provided with a hole for passing a screw shaft. In other words, the screw 18 is indirectly fastened to the screw hole 22 provided in the heat radiating plate 21 with the screw 18. The heat sink 21 arranged in place of the heat sink 2 has a planar shape that is slightly larger than the arrangement surface shape of the semiconductor modules 1 arranged side by side, and the screw holes 22 are in the longitudinal direction of the reinforcing beam 95. It is provided on the outside of the semiconductor modules 1 that are juxtaposed so as to be in a position corresponding to the screw through hole 30 provided at the end (both ends in FIG. 3).

  In this way, by adopting a structure in which both ends in the longitudinal direction of the reinforcing beam 95 are fastened to the heat radiating plate 21 side by screws 18, the screw 11 fixes the semiconductor module 1 disposed on the outermost side of the heat radiating plate 21. The outside is not in a cantilevered state with the screw 11 as a fulcrum as in the semiconductor device disclosed in Japanese Patent Application Laid-Open No. 2005-23592, and both ends of the reinforcing beam 95 are not in a cantilevered state, Since deformation of the heat radiating plate 21 and the reinforcing beam 95 is suppressed, it is easy to secure a pressure contact force between the semiconductor module 1 and the heat radiating plate 21, thereby realizing a stable state with low thermal resistance between the semiconductor module 1 and the heat radiating plate 21. be able to.

The reinforcing beam 95 is provided with a protrusion 15 for pressing the end of the semiconductor module 1 on the back side. For example, the protrusion amount is the same for all protrusions.
Further, as in the first embodiment described above, the protrusions 17 provided at both ends in the longitudinal direction of the reinforcing beam 94 are structured to protrude from the other protrusions 15, and after adjusting the protrusion amount, this embodiment is described. 2 can also be applied. Further, when the fixing at the both ends of the reinforcing beam 95 can be sufficiently performed by the screw 18, the protruding amount of the protrusion closer to the center of the reinforcing beam 95 is set at the both ends for the purpose of suppressing the floating at the center in the longitudinal direction of the reinforcing beam 95. You may make it comprise larger than a processus | protrusion. The protrusion amount of the protrusion can be appropriately adjusted according to the semiconductor module 1 to be used. The same can be said for the projections provided on the reinforcing beams in the third and fourth embodiments described later.

  Further, the above-described reinforcing beam 95 is applied to the semiconductor device using the heat sink 2, and screw holes corresponding to the screws 18 disposed at both ends of the reinforcing beam 95 are provided on the heat sink 2, and both ends of the reinforcing beam 95 are provided. It goes without saying that the problem caused by the fact that both ends of the reinforcing beam become cantilever beams can be solved by adopting a structure in which the portion is fastened and fixed to the heat sink 2 side by screws 18.

Embodiment 3 FIG.
4 is an exploded perspective view showing a semiconductor device according to Embodiment 3 of the present invention. As shown in FIG. 4, the third embodiment has basically the same configuration as the semiconductor device shown in the second embodiment described above, but uses a spacer 31 as a member that replaces the spacer 19. Is different. The spacer 19 described above is a cylindrical member for passing the screw shaft. However, the spacer 31 according to the third embodiment has a screw portion 32 protruding downward and a screw head for tightening the screw portion 32 at the upper portion. 33 and has a screw hole dug from the top of the screw head 33 so as to be coaxial with the screw portion 32.

  The screw portion 32 is fastened to the screw hole 22 provided in the heat radiating plate 21, and the screw 18 that fixes the end of the reinforcing beam 95 is fastened to the screw hole on the screw head 33 side. As a result, the end of the reinforcing beam 95 is indirectly fixed to the heat sink 21 via the spacer 31, and the deformation of the heat sink 21 is suppressed as in the second embodiment. Therefore, the semiconductor module 1 and the heat sink Therefore, it is easy to secure the pressure contact force 21, and the thermal resistance between the semiconductor module 1 and the heat radiating plate 21 is low and a stable state can be realized.

  In the third embodiment, the purpose of the above configuration is to facilitate the automation of assembly. In the case of the second embodiment, since the position of the spacer 19 is not fixed until the screw 18 is fastened, when the assembly is automated, the spacer 19 is positioned by some method until the screw 18 is fastened. Or it was necessary to fix temporarily.

  However, by using the spacer 31 whose lower portion is the screw portion 32 as in the third embodiment, the screw portion 32 protruding downward can be fitted into the screw hole 22 provided in the heat radiating plate 21 and fastened and fixed. Even in a state where the screw 18 for fastening the reinforcing beam 95 is not fastened, the spacer 31 can be positioned and fixed, so that the assembly can be easily automated.

Embodiment 4 FIG.
5 is an exploded perspective view showing a semiconductor device according to Embodiment 4 of the present invention. As shown in FIG. 5, the present embodiment has substantially the same configuration as the semiconductor device shown in the second and third embodiments, but the spacer 19 or 31 is interposed between the reinforcing beam 95 and the heat sink 21. The reinforcing beam 96 is bent directly at both ends, and the reinforcing beam 96 is directly fixed to the heat radiating plate 21 with screws 18.

  According to the fourth embodiment, a spacer is not provided between the reinforcing beam 96 and the heat radiating plate 21, and both ends are bent and the reinforcing beam 96 having a height corresponding to the spacer is used to reinforce. Since the beam 96 is directly fixed to the heat radiating plate 21, the number of parts can be reduced as compared with the second and third embodiments described above, and the same effect can be obtained at a lower cost.

  In the second to fourth embodiments, the presence / absence of protrusions and the amount of protrusion provided on the reinforcing beam may be optimized as appropriate. For example, the protrusions disposed at both ends or one end of the reinforcing beam are eliminated. Needless to say, the structure may be used.

1 is an exploded perspective view of a semiconductor device according to a first embodiment of the present invention. It is a side view of the reinforcement beam by Embodiment 1 of this invention. It is a disassembled perspective view of the semiconductor device by Embodiment 2 of this invention. It is a disassembled perspective view of the semiconductor device by Embodiment 3 of this invention. It is a disassembled perspective view of the semiconductor device by Embodiment 4 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Semiconductor module 2 Heat sink 3 Power supply terminal 4 Output terminal 5, 8, 10, 30 Screw through-hole 6, 22 Screw hole 11, 18 Screw 14 Slit 15, 17 Protrusion 19, 31 Spacer 21 Heat sink 32 Screw part 33 Screw Head 41 Signal terminal 71 Presser plate spring 94, 95, 96 Reinforcement beam.

Claims (2)

  A semiconductor module in which a semiconductor element is sealed with a resin and a screw through hole is provided in the center, a plate spring for pressing disposed on the upper surface side of the semiconductor module, and a plate spring for pressing which is disposed on the plate spring for pressing A reinforcing beam that reinforces the plate spring, and a heat sink or a heat radiating plate disposed on the back side of the semiconductor module, the semiconductor module from the reinforcing beam side through the reinforcing beam and the pressing plate spring. It is fixed to the heat sink side or the heat radiating plate side by screws inserted into the screw through holes of the semiconductor module, and the reinforcing beam applies the tightening load by the screws to the back surface side in contact with the pressing plate spring. A plurality of protrusions to be transmitted to the plate-like spring side, and the protrusions positioned at the longitudinal ends of the reinforcing beams are disposed closer to the longitudinal center of the reinforcing beams. Wherein a projection amount is larger than the electromotive.   A semiconductor module in which a semiconductor element is sealed with a resin and a screw through hole is provided in the center, a plate spring for pressing disposed on the upper surface side of the semiconductor module, and a plate spring for pressing which is disposed on the plate spring for pressing A reinforcing beam that reinforces the plate spring, and a heat sink or a heat radiating plate disposed on the back side of the semiconductor module, the semiconductor module from the reinforcing beam side through the reinforcing beam and the pressing plate spring. A semiconductor device characterized in that it is fixed to the heat sink side or the heat sink side by screws inserted into screw through holes of a semiconductor module, and both longitudinal ends of the reinforcing beam are fastened to the heat sink side or the heat sink side. apparatus.

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