JP2012222022A - Semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor device with improved reliability of a bonding portion between a substrate and heat sink composed of dissimilar materials.SOLUTION: A semiconductor device 1 according to the present invention comprises: a substrate 20 or 22 on which a semiconductor element is mounted; a heat sink 40 that is bonded on the side opposite to the arrangement side of the semiconductor element on the substrate and has a thermal expansion coefficient larger than that of the substrate; and a thermal deformation suppressing member 70 (710, 720, 730, and 740) that is provided on the heat sink, has a thermal expansion coefficient smaller than that of the heat sink, and suppresses the thermal expansion of the heat sink in the direction parallel to the bonding surface between the heat sink and the substrate.

Description

  The present invention relates to a semiconductor device in which a substrate and a heat sink are joined.

  Conventionally, this type of semiconductor device is known (see, for example, Patent Document 1). In Patent Document 1, a semiconductor chip is disposed on a heat spreader (substrate) made of copper, aluminum, or the like, and the heat spreader and the heat sink are bonded via a heat conductive sheet.

JP 2005-268514 A

  By the way, when the substrate and the heat sink are made of different materials having different thermal expansion coefficients, the reliability of the joint between the substrate and the heat sink may be impaired due to the difference in the thermal expansion coefficients between these different materials. is there. For example, if the board is made of copper and the heat sink is made of aluminum, the thermal stress at the joint between the board and the heat sink is caused by the fact that the thermal expansion coefficient of aluminum is significantly larger than that of copper. As a result, peeling occurs at the joint, and reliability may be impaired.

  On the other hand, it is possible to improve the bonding reliability by improving the resin adhesive and resin sheet used for bonding between the substrate and the heat sink, adjusting the thickness of the adhesive layer, and modifying the bonding surface. . However, the countermeasures of such an approach may cause adverse effects such as an increase in thermal resistance at the joint and deterioration of thermal conductivity and an increase in size (thickness).

  Accordingly, an object of the present invention is to provide a semiconductor device in which the reliability of a joint portion between a substrate and a heat sink made of different materials is improved.

To achieve the above object, according to one aspect of the present invention, a substrate on which a semiconductor element is disposed;
A heat sink bonded to the side opposite to the side of the semiconductor element on the substrate and having a larger thermal expansion coefficient than the substrate;
A thermal deformation suppression member provided on the heat sink, having a smaller thermal expansion coefficient than the heat sink, and suppressing thermal expansion of the heat sink in a direction parallel to a bonding surface between the heat sink and the substrate. A semiconductor device is provided.

  According to the present invention, it is possible to obtain a semiconductor device in which the reliability of a joint portion between a substrate made of a different material and a heat sink is improved.

It is sectional drawing which shows the principal part of an example of the semiconductor device 1 which can apply this invention. FIG. 6 is a perspective view showing a single item state of a restraining ring 710 that is an example of a thermal deformation suppressing member 70. FIG. 3 is a three-side view illustrating a mounting state of the restraining ring 710 illustrated in FIG. 2. It is a figure which shows typically the restraint principle of the heat sink 40 by the restraint ring 710. FIG. It is a perspective view which shows the single-piece | unit state of the restraint embedding bar | burr 720 which is another Example of the thermal deformation suppression member 70. FIG. FIG. 6 is a three-side view illustrating a mounting state of the constraint embedding bar 720 illustrated in FIG. 5. It is a figure which shows typically the restraint principle of the heat sink 40 by the restraint embedding bar | burr 720. FIG. It is a top view which shows the other attachment state of the restraint embedding bar | burr 720 shown in FIG. It is a top view which shows the single-item state of the restraint embedding bar | burr 730 which is another Example of the thermal deformation suppression member 70. FIG. It is a top view which shows the single item state of the restraint embedding board 740 which is another Example of the thermal deformation suppression member 70. FIG. 4 is a cross-sectional view of a constraining embedding plate 740 in a heat sink 40. FIG. It is sectional drawing which shows the other example of a board | substrate.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  FIG. 1 is a cross-sectional view showing a main part of a semiconductor device 1 according to an embodiment of the present invention. The vertical direction of the semiconductor device 1 differs depending on the mounting state of the semiconductor device 1, but in the following, for convenience, the chip 10 side of the semiconductor device 1 is upward. The semiconductor device 1 may constitute an inverter for driving a motor used in, for example, a hybrid vehicle or an electric vehicle.

  As shown in FIG. 1, the semiconductor device 1 includes a chip 10, a heat spreader 20, an insulating layer 30, and a heat sink 40.

  The chip 10 includes a power semiconductor element, and in this example includes an IGBT (Insulated Gate Bipolar Transistor). Note that the type and number of power semiconductor elements included in the chip 10 are arbitrary. The chip 10 may include another switching element such as a MOSFET (Metal Oxide Semiconductor Field-Effect Transistor) instead of the IGBT. The chip 10 is bonded onto the heat spreader 20 with solder 50.

  The heat spreader 20 is a member that absorbs and diffuses heat generated in the chip 10. The heat spreader 20 is formed from a metal having excellent thermal diffusibility, such as copper or aluminum. In this example, as an example, the heat spreader 20 is made of copper. As copper, oxygen-free copper (C1020) having the highest conductivity among copper materials is suitable. Copper typically has a coefficient of thermal expansion of 17 ppm / ° C.

  The insulating layer 30 may be composed of a resin adhesive or a resin sheet. The insulating layer 30 may be formed of a resin using alumina as a filler, for example. The insulating layer 30 is provided between the heat spreader 20 and the heat sink 40 and is bonded to the heat spreader 20 and the heat sink 40. The insulating layer 30 ensures high thermal conductivity from the heat spreader 20 to the heat sink 40 while ensuring electrical insulation between the heat spreader 20 and the heat sink 40.

  The heat sink 40 is formed of a material having good thermal conductivity, and is formed of a metal such as aluminum, for example. In this example, the heat sink 40 is made of aluminum. Aluminum typically has a coefficient of thermal expansion of 24 ppm / ° C.

  As described above, the upper surface of the heat sink 40 is bonded to the heat spreader 20. As shown in FIG. 1, the heat sink 40 includes fins 42 on the lower surface side. The number and arrangement of the fins 42 are arbitrary. The fins 42 may be straight fins as illustrated, or may be realized by staggered arrangement of pin fins. In the mounted state of the semiconductor module 1, the fins 42 are in contact with a cooling medium such as cooling water or cooling oil. In this way, the heat from the chip 10 generated when the semiconductor device 1 is driven is transmitted to the cooling medium from the fins 42 of the heat sink 40 via the heat spreader 20 and the insulating layer 30, and cooling of the semiconductor device 1 is realized. The

  The heat sink 40 is provided with a thermal deformation suppressing member 70 that suppresses thermal expansion of the heat sink 40. The thermal deformation suppression member 70 is a member that mechanically restrains thermal expansion of the heat sink 40 in a direction parallel to the joint surface between the heat sink 40 and the heat spreader 20. The thermal deformation suppressing member 70 has a smaller thermal expansion coefficient than the heat sink 40. Further, the thermal deformation suppressing member 70 preferably has a smaller thermal expansion coefficient than that of the heat spreader 20. Further, the thermal deformation suppressing member 70 receives a reaction force from the heat sink 40 when suppressing the thermal expansion of the heat sink 40 as will be described later. It is desirable. For example, the thermal deformation suppression member 70 may be formed of, for example, iron (thermal expansion coefficient of 11 ppm / ° C.) or alumina (thermal expansion coefficient of 5 ppm / ° C.).

  Hereinafter, the configuration of the thermal deformation suppressing member 70 will be described in detail. In FIG. 1, a restraining ring 710 described below with reference to FIGS. 2 and 3 is illustrated as an example of the thermal deformation suppressing member 70. As a definition of the term, “outside” refers to the center O of the semiconductor device 1 when viewed perpendicularly to the bonding surface between the heat sink 40 and the heat spreader 20 (hereinafter also simply referred to as “plane direct view”) (see FIG. 3). That is, “outside” means a side away from the center O of the semiconductor device 1 when viewed from the surface. Note that the center O of the semiconductor device 1 only needs to be approximately, and is not of a nature that should be strictly determined.

  FIG. 2 is a perspective view showing a single product state of a restraining ring 710 which is an embodiment of the thermal deformation suppressing member 70. FIG. 3 is a three-sided view showing a mounting state of the restraining ring 710 shown in FIG. For ease of understanding, FIG. 3 schematically shows only a part of the configuration of the semiconductor device 1 (the heat spreader 20, the insulating layer 30, and the heat sink 40) in addition to the restraining ring 710.

  The constraining ring 710 is formed in a ring shape as shown in FIG. As shown in FIG. 3, the restraining ring 710 is fitted to the side surface 44 of the heat sink 40 in such a manner as to surround the side surface 44 of the heat sink 40 from four directions. The constraining ring 710 is configured such that the gap between the inner surface 712 of the constraining ring 710 and the side surface 44 of the heat sink 40 is substantially zero when fitted around the heat sink 40. Alternatively, using the fact that the thermal expansion coefficient of the constraining ring 710 is smaller than the thermal expansion coefficient of the heat sink 40, the restraint ring 710 is fitted around the heat sink 40 contracted at a low temperature, and in the contraction direction on the side surface 44 of the heat sink 40 at room temperature. You may give power. That is, the restraining ring 710 may apply an initial force to the heat sink 40 in the shrinkage direction of the heat sink.

  Further, the restraining ring 710 may be provided over the entire thickness of the heat sink 40 (excluding the fins 42) in the thickness direction of the heat sink 40, or as shown in FIGS. It may be provided only in a part of the direction (the lower part in the illustrated example). Further, the restraining ring 710 may be provided so as to surround the fins 42 of the heat sink 40 from the outside. Further, as shown in FIG. 1 (indicated by reference numeral 70 in FIG. 1), the restraining ring 710 may be fitted into a recess 44a formed on the side surface 44 of the heat sink 40, or when such a recess 44a does not exist. May be fitted directly onto the flat side surface 44 of the heat sink 40.

  FIG. 4 is a diagram schematically showing the restraining principle of the heat sink 40 by the restraining ring 710, and is a diagram showing the heat sink 40 and the restraining ring 710 in a top view. Here, for simplification, it is assumed that the heat sink 40 has a square outer shape. E1 represents the amount of thermal expansion of the single heat sink 40 when the predetermined temperature rises (the amount of thermal expansion when not restrained by the restraining ring 710), and E2 represents the restraining ring 710 when the same predetermined temperature rises. Represents the amount of thermal expansion of a single product.

  Since the thermal expansion coefficient of the constraining ring 710 is smaller than the thermal expansion coefficient of the heat sink 40, the heat sink 40 tends to expand larger than the constraining ring 710 under the same temperature environment as shown in FIG. To do. That is, E1 is larger than E2. However, since the restraining ring 710 is fitted to the outside of the heat sink 40, the heat sink 40 cannot freely expand by E1. That is, the heat sink 40 receives a force in the contraction direction by the restraining ring 710, and thermal expansion is suppressed. Thus, according to the present embodiment, by providing the restraining ring 710, the thermal expansion coefficient of the heat sink 40 can be equivalently reduced. Thereby, the difference of the thermal expansion coefficient between the heat sink 40 and the heat spreader 20 can be substantially reduced, and the thermal stress generated at the joint between the heat sink 40 and the heat spreader 20 can be reduced. As a result, the reliability of the joint between the heat sink 40 and the heat spreader 20 can be increased.

  According to the present embodiment, as described above, the substantial thermal expansion coefficient of the heat sink 40 becomes smaller than the original thermal expansion coefficient of the heat sink 40 by the combination with the restraining ring 710. The substantial thermal expansion coefficient of the heat sink 40 changes depending on the configuration of the restraining ring 710 (the thermal expansion coefficient of the restraining ring 710, how to fit the restraining ring 710, the fitting range, etc.). Therefore, the configuration of the restraining ring 710 may be adjusted so that the substantial thermal expansion coefficient of the heat sink 40 is the same as the thermal expansion coefficient of the heat spreader 20. In this case, the difference in thermal expansion coefficient between the heat sink 40 and the heat spreader 20 can be substantially eliminated. In order to realize such a configuration, it is effective to make the thermal expansion coefficient of the restraining ring 710 smaller than the thermal expansion coefficient of the heat spreader 20.

  Further, according to the present embodiment, the restraining ring 710 is disposed outside the heat spreader 20 in a face-on view, so that the restraining ring 710 does not hinder heat conduction from the heat spreader 20 to the heat sink 40.

  FIG. 5 is a perspective view showing a single product state of the restraining embedded bar 720 which is another embodiment of the thermal deformation suppressing member 70. FIG. 6 is a three-sided view showing a mounting state of the constraint embedding bar 720 shown in FIG. For ease of understanding, FIG. 5 schematically shows only a part of the configuration of the semiconductor device 1 (the heat spreader 20, the insulating layer 30, and the heat sink 40) in addition to the constraint embedding bar 720.

  The constraint embedding bar 720 is a rod-like or plate-like member as shown in FIG. The basic cross-sectional shape of the constraint embedding bar 720 may be arbitrary including a circular shape, a rectangular shape, an elliptical shape, or the like. The restraining embedding bar 720 has a recess 722. As shown in FIG. 5, the concave portion 722 may be realized by an opening that penetrates, or may be realized by a recess that does not penetrate. Further, the constraint embedding bar 720 may have a notch 724 for allowing the plurality of constraint embedding bars 720 to intersect (see P part in FIG. 6).

  The constraint embedding bar 720 is embedded in the heat sink 40 by aluminum die casting. That is, the heat sink 40 is manufactured by aluminum die casting by inserting the restraining embedded bar 720. Thereby, the constraint embedding bar 720 is integrated with the heat sink 40 and can effectively exhibit the constraint action described later.

  The constraint embedding bar 720 is arranged so as to surround a part of the inside of the heat sink 40 from the outside (enclose from four sides). In the illustrated example, four constraint embedding bars 720 are embedded in the heat sink 40 so as to surround a part of the inside of the heat sink 40 from four sides as shown in FIG. The restraint embedding bar 720 is embedded such that the side surface 726 (see FIG. 5) faces the side surface 44 of the heat sink 40. Further, the two adjacent constraint embedding bars 720 are arranged upside down with respect to each other so as to be able to intersect with the notch 724. It should be noted that the connection between the constraint embedding bars 720 via the notches 724 may be strong or may have a backlash.

  The restraining embedding bar 720 may be provided over the entire thickness of the heat sink 40 (excluding the fin 42) in the thickness direction of the heat sink 40, or as shown in FIG. It may be provided only in part (in the illustrated example, the lower part). Further, the portion outside the intersecting position in each constraint embedding bar 720 may be omitted.

  FIG. 7 is a diagram schematically showing the principle of restraint of the heat sink 40 by the restraint embedding bar 720, and is a diagram showing a part of the heat sink 40 and the restraint embedding bar 720 (periphery of the recess 722) in a plane view.

  Here, as shown in FIG. 7, a part 400 inside the concave part 722 of the constrained embedding bar 720, a part 402 outside the concave part 722, and a part 404 inside the concave part 722 are assumed. These parts 400, 402, and 404 are parts of the heat sink 40. When the heat sink 40 is thermally expanded, the portions 400, 402, and 404 tend to move mainly in the direction of the arrow shown in FIG. On the other hand, the restraining embedded bar 720 also thermally expands in the same direction, but the expansion amount is relatively small because the thermal expansion coefficient is smaller than that of the heat sink 40. Accordingly, the movement of the portion 404 inside the recess 722 is suppressed by the recess 722 of the restraining embedding bar 720. That is, the portion of the heat sink 40 inside the recess 722 receives the force F shown in FIG. 7, and thermal expansion is suppressed. A portion 402 outside the recess 722 and a portion 404 inside the recess 722 are integrated with the portion 400 inside the recess 722, respectively. Accordingly, the movement of the portion 402 outside the concave portion 722 and the portion 404 inside the concave portion 722 are suppressed by the concave portion 722 of the restraining embedding bar 720 together with the portion 400 inside the concave portion 722. That is, a predetermined portion (portion 400) inside the heat sink 40 that is to be thermally expanded is caught by the recess 722, so that a reaction force in the contraction direction is applied to the entire heat sink 40. Thus, according to the present embodiment, the thermal expansion coefficient of the heat sink 40 can be equivalently reduced by providing the constraint embedding bar 720. Thereby, the difference of the thermal expansion coefficient between the heat sink 40 and the heat spreader 20 can be substantially reduced, and the thermal stress generated at the joint between the heat sink 40 and the heat spreader 20 can be reduced. As a result, the reliability of the joint between the heat sink 40 and the heat spreader 20 can be increased. Although the restraint principle when the heat sink 40 is thermally expanded has been described with reference to FIG. 7, the restraint embedding bar 720 suppresses the thermal contraction of the heat sink 40 based on the same principle when the heat sink 40 is thermally contracted. be able to.

  According to the present embodiment, as described above, the substantial thermal expansion coefficient of the heat sink 40 becomes smaller than the original thermal expansion coefficient of the heat sink 40 by the combination with the restraining embedded bar 720. The substantial thermal expansion coefficient of the heat sink 40 depends on the configuration of the constraint embedding bar 720 (the thermal expansion coefficient of the constraint embedding bar 720, the number of the constraint embedding bars 720, the number, the range, and the depth of the recesses 722 of the constraint embedding bar 720. Etc.). Therefore, the configuration of the constraint embedding bar 720 may be adjusted so that the substantial thermal expansion coefficient of the heat sink 40 is the same as the thermal expansion coefficient of the heat spreader 20. In this case, the difference in thermal expansion coefficient between the heat sink 40 and the heat spreader 20 can be substantially eliminated. In order to realize such a configuration, it is effective to make the thermal expansion coefficient of the restraining embedded bar 720 smaller than the thermal expansion coefficient of the heat spreader 20.

  In addition, according to the present embodiment, the constraint embedding bar 720 is disposed outside the heat spreader 20 in a face-on view, so that the constraint embedding bar 720 may inhibit heat conduction from the heat spreader 20 to the heat sink 40. Absent.

  In this embodiment, when the constraining embedded bars 720 are firmly coupled by welding or the like, the thermal expansion of the heat sink 40 can be suppressed based on the same constraining principle as that of the constraining ring 710 described above.

  FIG. 8 is a top view showing another attachment state of the constraint embedding bar 720 shown in FIG. Two constraining embedding bars 720 may be provided so as to intersect at substantially the center of the heat sink 40 when viewed from the surface. In this case, the constraint embedding bar 720 is disposed below the heat spreader 20 in a face-on view, so that heat conduction from the heat spreader 20 to the heat sink 40 is worse than that in the attached state shown in FIG. The thermal expansion of the heat sink 40 and the heat spreader 20 can be effectively suppressed similarly, and the reliability of the joint between the heat sink 40 and the heat spreader 20 can be improved. In the example shown in FIG. 8, only two constraint embedding bars 720 are provided. However, further constraint embedding bars 720 may be arranged in parallel to these. Further, the embedding method of the constraint embedding bar 720 shown in FIG. 8 can be realized in combination with the embedding method of the constraint embedding bar 720 of the constraint embedding bar 720 shown in FIG.

  FIG. 9 is a plan view showing a single article state of the restraining embedded bar 730 which is another embodiment of the thermal deformation suppressing member 70.

  The constraint embedding bar 730 is a rod-like or plate-like member as shown in FIG. The restraint embedding bar 730 has a recess 732. As shown in FIG. 9, the recess 732 may be realized by a through-opening (notch) or may be realized by a recess that does not penetrate. The constraint embedding bar 730 may be embedded in the heat sink 40 in the same manner as the constraint embedding bar 720 according to the above-described embodiment. Such a constraint embedding bar 730 can provide the same effects as the constraint embedding bar 720 according to the above-described embodiment.

  As described above, there are various setting modes of the recesses in the constraint embedding bar, and the shape, position, number, and the like of the recesses are arbitrary. Further, a convex portion may be provided instead of or in addition to the concave portion. Also in the case of a convex part, the same effect can be produced based on the restriction principle similar to the restriction principle shown in FIG. That is, a predetermined portion inside the heat sink 40 that is to be thermally expanded is caught by the convex portion, whereby a reaction force in the contraction direction is applied to the entire heat sink 40. Further, the direction of the unevenness is also arbitrary. For example, in the case of the restraining embedded bars 720 and 730, the recesses 722 and 732 are oriented in a direction perpendicular to the side surface 44 of the heat sink 40, but are oblique to the side surface 44 of the heat sink 40 (and the heat sink 40 and the heat spreader). Or a direction perpendicular to the bonding surface between the heat sink 40 and the heat spreader 20 (see FIG. 10 and FIG. 11). You may face the direction of arbitrary combinations.

  FIG. 10 is a plan view showing a single product state of a constraining embedded plate 740 that is another embodiment of the thermal deformation suppressing member 70. FIG. 11 is a cross-sectional view of the restraining embedding plate 740 in the heat sink 40.

  The restraint embedding plate 740 is a plate-like member and has a recess 742 having a recess in the direction perpendicular to the surface. The recess 742 is preferably realized by an opening therethrough as shown in FIG. A convex portion (peripheral wall) 744 may be formed around the concave portion 742 as shown in FIG. In this case, the restraint principle shown in FIG. 7 can be exhibited by both the concave portion 742 and the convex portion 744.

  The restraint embedding plate 740 is embedded in the heat sink 40 as shown in FIG. The constraint embedding plate 740 is embedded in the heat sink 40 by aluminum die casting, like the constraint embedding bar 720 according to the above-described embodiment. The restraint embedding plate 740 is embedded in the heat sink 40 such that the direction perpendicular to the plane (the direction perpendicular to the plane of FIG. 10) corresponds to the direction perpendicular to the bonding surface between the heat sink 40 and the heat spreader 20 (the direction perpendicular to the plane). .

  The constraint embedding plate 740 according to the present embodiment is suitable for the semiconductor device 1 in which the six chips 10 are incorporated. That is, the constraining embedding plate 740 is provided with six recesses 742 corresponding to each of the six chips 10. The size of each recess 742 is preferably set larger than the outer shape of the heat spreader 20 provided below the corresponding chip 10. This prevents the heat conduction from each heat spreader 20 to the heat sink 40. The six chips 10 may constitute a total of six arms, that is, the U-phase, V-phase, and W-phase upper arms and lower arms of the inverter for driving the motor.

  The restraint embedding plate 740 may have a single recess 742 when applied to the semiconductor device 1 in which the single chip 10 is incorporated. Thus, the recesses 742 may be set according to the number of chips 10. Moreover, in this example, the recessed part 742 which is opening may be equipped with several mesh-shaped small recessed parts inside.

  The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above-described embodiments, and various modifications and substitutions can be made to the above-described embodiments without departing from the scope of the present invention. Can be added.

  For example, in the above-described embodiment, the substrate on which the chip 10 is disposed is the heat spreader 20, but as long as the thermal expansion coefficient of the heat sink 40 is larger than the thermal expansion coefficient of the substrate, the present invention is not limited to any other substrate. It is also applicable to. For example, as shown in FIG. 12, the substrate 22 is a DBA (Direct Brazed Aluminum) substrate having aluminum plates on both surfaces of a ceramic substrate having high thermal conductivity, or a DBC (Direct Braided Aluminum) substrate having copper plates on both surfaces of the ceramic substrate. Brazed Copper) substrate. In this case, the substrate 22 may be bonded to the heat sink 40 with the solder 50. Also in this case, the thermal stress is generated due to the difference between the thermal expansion coefficient of DBA or DBC and the thermal expansion coefficient of the heat sink 40, thereby causing cracks in the solder 50 and the reliability of the joint between the substrate and the heat sink. It is because there is a possibility that the property may be impaired.

  In the above-described embodiment, the material of the heat spreader 20 is copper and the material of the heat sink 40 is aluminum. However, in the present invention, the thermal expansion coefficient of the heat sink 40 is higher than the thermal expansion coefficient of the heat spreader 20 (substrate). As long as it is large, the present invention can be applied to a combination composed of any other material.

  In the above-described embodiment, the heat spreader 20 and the heat sink 40 are improved by improving the resin adhesive or the resin sheet used for bonding between the heat spreader 20 and the heat sink 40, adjusting the thickness of the adhesive layer, modifying the bonding surface, or the like. It is also possible to improve the reliability of the joint between the two. That is, the present invention is not incompatible with these approaches, and can be combined to obtain the required effects.

  Moreover, in the above-mentioned Example, although the heat sink 40 was comprised by one member, you may be comprised by two or more members. For example, the heat sink 40 may be configured by combining a first metal plate and a second metal plate including the fins 42. In this case, the thermal deformation suppressing member 70 according to the above-described embodiment may be provided on a metal plate (first metal plate) joined to the heat spreader 20.

  In the above-described embodiment, as a preferred embodiment, the case where the thermal deformation suppressing member 70 is provided on the outer side than the heat spreader 20 in a face direct view and is not provided below the heat spreader 20 has been described. However, when the heat spreader 20 is relatively large, for example, when the heat spreader 20 is shared by a plurality of chips 10, the thermal deformation suppression member 70 is provided outside the chip 10 mounting range in a surface direct view, It may not be provided below the chip 10 mounting range.

  In the above-described embodiment, the semiconductor device 1 is applied to a vehicle inverter. However, the semiconductor device 1 is an inverter used for other purposes (railway, air conditioner, elevator, refrigerator, etc.). May be used. Further, the semiconductor device 1 may be used in a device other than an inverter, for example, an MPU (Microprocessor Unit) for a computer or a high-frequency power module used in a power amplification circuit of a transmission unit of a wireless communication device.

1 Semiconductor Device 10 Chip 20 Heat Spreader 22 Substrate 30 Insulating Layer 40 Heat Sink 42 Fin 44 Side 44a Recess 50 Solder 70 Thermal Deformation Suppressing Member 710 Restraint Ring 720, 730 Restrained Embedding Bar 722, 732 Recess 724 Notch 740 Restrained Embedding Plate 742 Convex

Claims (5)

A substrate on which a semiconductor element is disposed;
A heat sink bonded to the side opposite to the side of the semiconductor element on the substrate and having a larger thermal expansion coefficient than the substrate;
A thermal deformation suppression member provided on the heat sink, having a smaller thermal expansion coefficient than the heat sink, and suppressing thermal expansion of the heat sink in a direction parallel to a bonding surface between the heat sink and the substrate. A semiconductor device.   The semiconductor device according to claim 1, wherein the thermal deformation suppressing member has a thermal expansion coefficient smaller than that of the substrate.   3. The semiconductor device according to claim 1, wherein the thermal deformation suppressing member is provided outside the substrate when viewed perpendicularly to a bonding surface between the heat sink and the substrate.   The semiconductor device according to claim 1, wherein the thermal deformation suppressing member is embedded in the heat sink and includes at least one of a concave portion and a convex portion.   The thermal deformation suppressing member is provided in such a manner as to surround the whole or a part of the inside of the heat sink from four sides when viewed perpendicularly to the bonding surface between the heat sink and the substrate. The semiconductor device according to any one of the above.

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