JP2007258291A - Semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor device which can be reduced in size and weight and has good heat dissipation characteristics.
A heat sink, a module placed on the heat sink via thermal conductive grease, a pressure plate placed on the module, and a pressure plate that presses the module toward the heat sink. In a semiconductor device that releases heat generated by the module from the heat sink via thermal conductive grease, the module is made of a resin-sealed module, and the heat sink is a support to which the fixture is fixed. A plate, and a flow path cover joined to the support plate to form a flow path for the cooling medium therebetween.
[Selection] Figure 1

Description

  The present invention relates to a semiconductor device, and more particularly to a power semiconductor device in which a resin-sealed module is fixed to a heat sink.

Case type modules are used in conventional power semiconductor devices. The case-type module includes a base plate, and a power semiconductor element such as an IGBT is placed on the base plate via an insulating substrate. The base plate is made of copper, for example, and the insulating substrate is made of ceramic, for example. The base plate is fixed on a heat sink made of copper, for example, using screws. Thermal conductive grease is applied between the base plate and the heat sink to increase thermal conductivity (see, for example, Patent Document 1).
JP 2001-148451 A

  The heat conductive grease is made of a viscous material containing several tens of weight% or more of filler, and the heat conductivity is about 0.8 to 4 W / m · K. Such thermal conductivity is extremely small as compared with the thermal conductivity of copper constituting the base plate and the heat sink, which is about 400 W / m · K. For this reason, in order to improve the heat dissipation characteristics, it is necessary to reduce the film thickness of the heat conduction grease to be, for example, 0.1 mm or less, and the heat conduction grease is thinned by fastening the base plate to the heat sink with a screw. .

  However, in the case type module, in the process of fixing the insulating substrate to the base plate with a solder material, the base plate is bent due to the difference in linear expansion coefficient between the base plate and the insulating substrate. For this reason, in order to reduce the thickness of the thermal conductive grease between the base plate and the heat sink, it is necessary to tighten the base plate to the heat sink with screws and to extend the curved base plate flatly. It is necessary to. As a result, the size of the heat sink has been limited in order to reduce the size and weight of the semiconductor device.

  Therefore, an object of the present invention is to provide a semiconductor device that can be reduced in size and weight and has good heat dissipation characteristics.

  The present invention relates to a heat sink, a module placed on the heat sink via thermal conductive grease, a pressure plate placed on the module, and the pressure plate to the heat sink so as to press the module toward the heat sink. A semiconductor device that releases heat generated by the module from the heat sink through thermal conductive grease, the module being a resin-sealed module, and the heat sink having the fixture fixed And a flow path cover that is joined to the support plate and forms a flow path for the cooling medium therebetween.

  In the semiconductor device according to the present invention, it is possible to reduce the size and weight while realizing good heat dissipation characteristics.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In the following description, “top”, “bottom”, “left”, “right” and names including these terms are used as appropriate, but these directions make it easy to understand the invention with reference to the drawings. Therefore, a mode in which the embodiment is inverted upside down or rotated in an arbitrary direction is naturally included in the technical scope of the present invention.

Embodiment 1 FIG.
FIG. 1 is a cross-sectional view of the semiconductor device according to the first embodiment, the whole being represented by 100. FIG. 2 is a perspective view of the semiconductor device 100 as viewed from the back side, and FIG. 1 corresponds to a cross section when FIG. 2 is viewed in the AA direction.

  The semiconductor device 100 includes a heat sink 10. The heat sink 10 includes a support plate 1 and a flow path cover 2 fixed to the back surface of the support plate 1 with a brazing material. The support plate 1 and the flow path cover 2 are made of aluminum, for example. Corrugated fins 3 made of corrugated thin plates are provided between the support plate 1 and the flow path cover 2. The corrugated fin 3 has, for example, a wavy portion of about 10 cycles, and is fixed to the support plate 1 and the flow path cover 2 with a brazing material. The corrugated fin 3 is made of, for example, a clad material in which an aluminum-silicon layer (a brazing material) is provided on both surfaces of an aluminum plate. The cooling medium flows between the corrugated fins 3 in a direction perpendicular to the paper surface of FIG.

  On the support plate 1, a resin-sealed module 5 is placed via a heat conductive grease 4. The heat conductive grease 4 is made of, for example, a silicone resin containing a filler. The resin-sealed module 5 has a structure in which a semiconductor element such as an IGBT or a lead (not shown) is sealed with an epoxy resin, for example. The lower surface of the resin-encapsulated module 5 is drawn with a slight curve, which is due to the shrinkage of the encapsulating resin. Of course, a resin-sealed module 5 having a flat bottom surface may be used.

  On the resin-sealed module 5, a pressing plate 6 made of, for example, aluminum is placed. The pressing plate 6 has a through hole, and is fixed to the support plate 1 of the heat sink 10 by a screw (fixing tool) 7 passing through the through hole.

  In the semiconductor device 100, the pressing plate 6 can be pressed against the resin-encapsulated module 5 by turning the screw 7. As a result, the resin-sealed module 5 is sandwiched between the support plate 1 and the holding plate 6 and the bottom surface becomes substantially flat, and the heat sealed between the resin-sealed module 5 and the support plate 1. The film thickness of the conductive grease 4 is also reduced.

  As described above, in the case type module, it is necessary to strongly tighten the base plate to the heat sink in order to extend the curved base plate flatly. For this reason, the heat sink is formed by cutting a copper bulk material having a thickness of 12 mm, for example, and has a large weight.

On the other hand, in the semiconductor device 100 according to the first embodiment, the heat sink 10 is disposed in, for example, an aluminum support plate 1 having a thickness of 2 mm, an aluminum flow path cover 2 having a thickness of 1 mm, and the like. It consists of a corrugated fin 3 made of a clad material (aluminum / aluminum-silicon) having a thickness of 0.5 mm. The flow path cover 2 that forms the flow path of the cooling medium has, for example, a width of 40 mm and a height of 8 mm.
As a result, in the semiconductor device 100, the weight of the heat sink can be reduced by about 90% compared to the conventional structure, and can be reduced to about 1/10. The heat transfer coefficient has a value of about 10,000 W / m · K.

  In addition, since the heat sink 10 can be formed simply by brazing the corrugated fin 3 formed by pressing the clad material and the flow path cover 2 to the support plate 1 without using the cutting process as in the conventional structure. The time is shortened, and the manufacturing cost can be reduced.

  Further, when the case type module is used, an area in which the through hole is provided in the base plate is necessary in order to fix the case type module and the heat sink by passing the screw through the base plate of the case type module. On the other hand, in the semiconductor device 100, since the resin-sealed module 5 is pressed and fixed to the heat sink 10 by the pressing plate 6, the resin-sealed module 5 can be reduced in size and cost.

  In Embodiment 1 of the present embodiment, the structure including two sets of the heat sink 10 and the resin-sealed module 5 has been described based on FIGS. 1 and 2, but the structure including one set or three or more sets may be used. (The same applies to the following embodiments).

  As shown in FIG. 2, the heat sink 10 is provided with a cooling medium introduction / discharge port 11. The introduction / discharge port 11 is also connected to the heat sinks 20 to 60 shown in the following third to seventh embodiments to supply / discharge the cooling medium.

Embodiment 2. FIG.
FIG. 3 is a cross-sectional view of the semiconductor device according to the second embodiment, the whole being represented by 200. In FIG. 3, the same reference numerals as those in FIG. 3 is a cross-sectional view when viewed in the same direction as the AA direction of FIG.

  In the semiconductor device 200, the corrugated fins 3 and the flow path cover 2 are formed on the support plate 1, and the resin-encapsulated module 5 is further provided on the support plate 1 via the heat conductive grease 4. A pressing plate 6 is placed on the resin-encapsulated module 5. By tightening the holding plate 6 to the support plate 1 with the screws 7, the heat conductive grease 4 sandwiched between the flow path cover 2 and the resin-sealed module 5 can be thinned.

  Similarly to the semiconductor device 100 described above, by forming the heat sink 10 from the support plate 1, the flow path cover 2, and the corrugated fins 3, it is possible to reduce the weight and cost of the heat sink 10.

  The upper surface of the flow path cover 2 (the area where the heat conductive grease 4 is applied) is sandwiched between the flow path cover 2 and the resin-sealed module 5 by forming a shape in which the vicinity of the center protrudes from both ends by several tens of μm. The heat conductive grease 4 thus easily escapes in the lateral direction, and the heat conductive grease 4 can be thinned.

  Thus, in the semiconductor device 200, the heat conduction grease 4 is thinned to increase the heat radiation efficiency, and the semiconductor device 200 can be reduced in size and weight.

Embodiment 3 FIG.
FIG. 4 is a cross-sectional view of the semiconductor device according to the third embodiment, which is indicated as a whole by 300. In FIG. 4, the same reference numerals as those in FIG. 4 is a cross-sectional view when viewed in the same direction as the AA direction of FIG.

  In the semiconductor device 300, the heat sink 20 is fixed on the support plate 1 by, for example, brazing. The heat sink 20 is formed by, for example, extrusion of aluminum, and the dimensions are, for example, 1 mm in thickness, 12 mm in height, and 40 mm in width. In this case, a cooling performance of about 10,000 W / m · K is obtained.

  On the heat sink 20, the resin-encapsulated module 5 is placed via the heat conductive grease 4. A pressing plate 6 is placed on the resin-encapsulated module 5. The holding plate 6 is fixed to the support plate 1 with screws 7.

  In such a structure, the heat sink 20 can be formed by extruding the aluminum member without cutting or brazing the flow path cover, and the heat sink 20 can be reduced in weight and cost. That is, in the semiconductor device 300, the heat conduction grease 4 is thinned to increase the heat radiation efficiency, and the semiconductor device 300 can be reduced in size and weight.

  Further, since brazing or the like is not used for forming the heat sink 20, the heat sink 20 having substantially the same shape can always be obtained. As a result, a substantially constant heat dissipation characteristic can be realized. Further, the margin necessary for brazing the flow path cover to the support plate is not required, and the heat sink 20 can be reduced in size and weight. Note that the space formed by the miniaturization of the heat sink 20 can be used for routing the wiring member of the resin-sealed module 5.

Embodiment 4 FIG.
FIG. 5 is a cross-sectional view of the semiconductor device according to the fourth embodiment, which is generally indicated by 400. In FIG. 5, the same reference numerals as those in FIG. FIG. 5 is a cross-sectional view when viewed in the same direction as the AA direction in FIG. 2.

  In the semiconductor device 400, the heat sink 30 is fixed on the support plate 1 by brazing or the like. The heat sink 30 is provided with a holding portion 31. The heat sink 30 and the holding part 31 are simultaneously formed, for example, by an extrusion process of an aluminum member.

  The holding unit 31 has a plane orthogonal to the paper surface of FIG. 5 and moves in the vertical direction with a restoring force. The distance between the heat sink 30 and the holding part 31 is slightly smaller than the height of the resin-encapsulated module 5. As a result, when the resin-sealed module 5 is placed on the heat sink 30 via the thermal conductive grease 4, the holding unit 31 presses the resin-sealed module 5 against the upper surface of the heat sink 30 and fixes it. . Specifically, after the thermal conductive grease 4 is applied to the upper surface of the heat sink 30 with a dispenser or the like, the holding unit 31 is lifted upward to place the resin-sealed module 5 at a predetermined position. Move back to the first position and fix.

  As described above, in the semiconductor device 400, the heat conduction grease 4 is thinned to increase the heat radiation efficiency, and the resin-encapsulated module 5 is fixed using the support portion 31 provided on the heat sink 30. It is possible to reduce the weight.

Embodiment 5 FIG.
FIG. 6 is a cross-sectional view of the semiconductor device according to the fifth embodiment, indicated as a whole by 500. In FIG. 6, the same reference numerals as those in FIG. FIG. 6 is a cross-sectional view when viewed in the same direction as the AA direction in FIG. 2.

  As shown in FIG. 6A, in the semiconductor device 500, the heat sink 40 is fixed on the support plate 1 by brazing or the like. The heat sink 40 is provided with two holding portions 41. At the tip of the holding part 41, a groove part 42 extending in a direction perpendicular to the paper surface is provided. The heat sink 40, the holding part 41, and the groove part 42 are simultaneously formed by, for example, extrusion processing of an aluminum member.

  Similar to the semiconductor device 400 described above, the holding portion 41 moves in the vertical direction with a restoring force, and the distance between the heat sink 40 and the holding portion 41 is slightly smaller than the height of the resin-encapsulated module 5. As a result, when the resin-sealed module 5 is placed on the heat sink 40 via the thermal conductive grease 4, the holding portion 41 presses the resin-sealed module 5 against the upper surface of the heat sink 40 and fixes it. .

  In particular, in the semiconductor device 500 according to the fifth embodiment, as shown in FIG. 6B, the resin-sealed module 5 is mounted on the heat sink with the temporary fixing jig 45 sandwiched between the facing groove portions 42. The temporary fixing jig 45 is removed in a state where it is inserted on 40 and placed at a predetermined position. Thereby, arrangement | positioning of the resin sealing type module 5 can be performed easily.

  Thus, in the semiconductor device 500, it is possible to reduce the size and weight while reducing the heat conduction grease 4 to increase the heat radiation efficiency. Further, the resin-sealed module 5 can be easily arranged.

Embodiment 6 FIG.
FIG. 7 is a cross-sectional view of the semiconductor device according to the sixth embodiment, indicated as a whole by 600. In FIG. 7, the same reference numerals as those in FIG. 7 is a cross-sectional view when viewed in the same direction as the AA direction in FIG.

  In the semiconductor device 600, the heat sink 50 is fixed on the support plate 1 by brazing or the like. The heat sink 50 is provided with two holding portions 51, and a groove portion 52 is provided at the tip of the holding portion 51. In particular, in the semiconductor device 500, the interval W <b> 2 between the holding portions 51 facing each other is larger than the width W <b> 1 of the resin-encapsulated module 5. The heat sink 50, the holding part 51, and the groove part 52 are formed at the same time, for example, by extrusion of an aluminum member.

  A holding plate 55 is inserted between the grooves, and the resin-sealed module 5 is pressed against and fixed to the upper surface of the heat sink 50 by the holding plate 55. The holding plate 55 is preferably provided with a protrusion 56.

  In the semiconductor device 600, the heat conductive grease 4 is applied on the heat sink 50, and the resin-sealed module 5 is disposed thereon. Since the interval W2 between the holding portions 51 is larger than the width W1 of the resin-sealed module 5, the resin-sealed module 5 can be easily arranged. Thereafter, the pressing plate 55 is inserted between the facing groove portions 52 in a direction perpendicular to the paper surface of FIG. Thereby, the resin-sealed module 5 is pressed against the upper surface of the heat sink 50 and fixed.

  Thus, in the semiconductor device 600, it is possible to reduce the size and weight while reducing the heat conduction grease 4 to increase the heat radiation efficiency. Further, the resin-sealed module 5 can be easily arranged.

  The material of the pressing plate 55 can be appropriately selected from metals, resins, and the like as long as the material has a predetermined rigidity. In particular, by using a metal capable of shielding magnetic force such as iron or aluminum as the material of the pressing plate 55, it is possible to block or reduce the magnetic field formed by the operation of the resin-sealed module, and to influence the outside. Can be prevented.

Embodiment 7 FIG.
FIG. 8 is a cross-sectional view of the semiconductor device according to the seventh embodiment, indicated as a whole by 700. In FIG. 8, the same reference numerals as those in FIG. FIG. 8 is a cross-sectional view when viewed in the same direction as the AA direction in FIG. 2.

  In the semiconductor device 700, a recess 62 is provided on the upper surface of the heat sink 60 in addition to the structure of the semiconductor device 400 described above. In addition, a protrusion 15 is provided on the back surface of the resin-encapsulated module 5 so as to fit into the recess 62. The protrusion 15 can be easily formed by performing resin sealing using a mold provided with a protrusion in the resin sealing step. The protrusion 15 has a cylindrical shape having a diameter of 2 mm and a height of 1 to 2 mm, for example. The protrusions 15 are provided at the positions of three apexes of a triangle, for example.

  In the step of placing the resin-sealed module 5 on the heat sink 60, the thermal conductive grease 4 is applied to the upper surface of the heat sink 60, and then the protrusion 15 is fitted into the recess 62 while sliding the resin-sealed module 5. In this process, since the resin-sealed module 5 slides while being supported by the protrusions 15, the resin-sealed module 5 can be easily moved. Further, the resin node module 5 can be disposed at a predetermined position of the heat sink 60.

  Thus, in the semiconductor device 700, the heat conduction grease 4 is thinned to increase the heat radiation efficiency, and the size and weight can be reduced. Further, the resin-sealed module 5 can be attached to a predetermined position of the heat sink 50.

It is sectional drawing of the semiconductor device concerning Embodiment 1 of this invention. It is a perspective view of the heat sink of the semiconductor device concerning Embodiment 1 of this invention. It is sectional drawing of the semiconductor device concerning Embodiment 2 of this invention. It is sectional drawing of the semiconductor device concerning Embodiment 3 of this invention. It is sectional drawing of the semiconductor device concerning Embodiment 4 of this invention. It is sectional drawing of the semiconductor device concerning Embodiment 5 of this invention. It is sectional drawing of the semiconductor device concerning Embodiment 6 of this invention. It is sectional drawing of the semiconductor device concerning Embodiment 7 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Support plate, 2 Flow path cover, 3 Corrugated fin, 4 Thermal conductive grease, 5 Resin sealing type module, 6 Holding plate, 7 Screw, 10 Heat sink, 100 Semiconductor device.

Claims (2)

A heat sink,
A module placed on the heat sink via heat conductive grease;
A holding plate placed on the module;
A fixing device for fixing the pressing plate to the heat sink so as to press the module toward the heat sink, and discharging the heat generated in the module from the heat sink through the heat conduction grease. And
The module consists of a resin-sealed module,
The heat sink includes a support plate to which the fixture is fixed, and a flow path cover that is joined to the support plate and forms a flow path for a cooling medium therebetween. The semiconductor device according to claim 1, wherein corrugated fins having a corrugated shape are provided between the support plate and the flow path cover.

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