WO2013018200A1 - Heat radiation unit and method for manufacturing same - Google Patents

Heat radiation unit and method for manufacturing same Download PDF

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Publication number
WO2013018200A1
WO2013018200A1 PCT/JP2011/067704 JP2011067704W WO2013018200A1 WO 2013018200 A1 WO2013018200 A1 WO 2013018200A1 JP 2011067704 W JP2011067704 W JP 2011067704W WO 2013018200 A1 WO2013018200 A1 WO 2013018200A1
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WO
WIPO (PCT)
Prior art keywords
heat pipe
heat
wall
radiating member
layer
Prior art date
Application number
PCT/JP2011/067704
Other languages
French (fr)
Japanese (ja)
Inventor
和也 浅岡
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トヨタ自動車株式会社
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Publication date
Application filed by トヨタ自動車株式会社 filed Critical トヨタ自動車株式会社
Priority to PCT/JP2011/067704 priority Critical patent/WO2013018200A1/en
Publication of WO2013018200A1 publication Critical patent/WO2013018200A1/en

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
    • F28D15/00—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies
    • F28D15/02—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies in which the medium condenses and evaporates, e.g. heat pipes
    • F28D15/0275—Arrangements for coupling heat-pipes together or with other structures, e.g. with base blocks; Heat pipe cores
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F1/00—Tubular elements; Assemblies of tubular elements
    • F28F1/006—Tubular elements; Assemblies of tubular elements with variable shape, e.g. with modified tube ends, with different geometrical features
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F13/00—Arrangements for modifying heat-transfer, e.g. increasing, decreasing
    • F28F13/14—Arrangements for modifying heat-transfer, e.g. increasing, decreasing by endowing the walls of conduits with zones of different degrees of conduction of heat
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L23/00—Details of semiconductor or other solid state devices
    • H01L23/34—Arrangements for cooling, heating, ventilating or temperature compensation ; Temperature sensing arrangements
    • H01L23/42—Fillings or auxiliary members in containers or encapsulations selected or arranged to facilitate heating or cooling
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L23/00—Details of semiconductor or other solid state devices
    • H01L23/34—Arrangements for cooling, heating, ventilating or temperature compensation ; Temperature sensing arrangements
    • H01L23/42—Fillings or auxiliary members in containers or encapsulations selected or arranged to facilitate heating or cooling
    • H01L23/427—Cooling by change of state, e.g. use of heat pipes
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F13/00—Arrangements for modifying heat-transfer, e.g. increasing, decreasing
    • F28F2013/005—Thermal joints
    • F28F2013/006—Heat conductive materials
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F2255/00—Heat exchanger elements made of materials having special features or resulting from particular manufacturing processes
    • F28F2255/18—Heat exchanger elements made of materials having special features or resulting from particular manufacturing processes sintered
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F2255/00—Heat exchanger elements made of materials having special features or resulting from particular manufacturing processes
    • F28F2255/20—Heat exchanger elements made of materials having special features or resulting from particular manufacturing processes with nanostructures
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F2275/00—Fastening; Joining
    • F28F2275/08—Fastening; Joining by clamping or clipping
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/26—Layer connectors, e.g. plate connectors, solder or adhesive layers; Manufacturing methods related thereto
    • H01L2224/2612—Auxiliary members for layer connectors, e.g. spacers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/0001—Technical content checked by a classifier
    • H01L2924/0002—Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00

Definitions

  • the technology disclosed in this specification relates to a heat radiating unit in which a heat pipe is connected to a heat radiating member (for example, a heating element or a heat conducting member).
  • a heat radiating member for example, a heating element or a heat conducting member.
  • Japanese Patent Publication No. 2004-130371 discloses a technique for connecting two members using metal nanoparticles.
  • the metal nanoparticles mean metal particles having a particle size of 100 nm or less.
  • a silver nanoparticle layer is disposed between two members, and then these members are heated to 200 ° C. to 300 ° C.
  • the silver nanoparticle layer is sintered by heating. That is, the silver nanoparticles in the silver nanoparticle layer are joined together. Thereby, a bulky silver layer is formed.
  • the silver nanoparticles are also bonded to the members by heating. Accordingly, the formed bulk silver layer is bonded to each member. That is, the two members are connected to each other by the bulk silver layer.
  • a heat radiating unit that releases heat from a heat radiating member to the heat radiating member by connecting the heat radiating member to the heat radiating member is known. Since the heat radiating unit becomes high temperature, it is preferable to connect the heat radiating member to the heat radiating member with a metal layer having a high melting point. According to the technique of connecting two members using the metal nanoparticles described above, a high melting point of 300 ° C. or higher is obtained by heat treatment at a relatively low temperature (in the above example, 200 ° C. to 300 ° C.). The heat radiating member and the heat radiating member can be connected by a metal layer (for example, silver having a melting point of about 960 ° C.).
  • this manufacturing method has a problem that high connection strength cannot be obtained unless the metal nanoparticles are heated in a state where a high pressure is applied to the metal nanoparticles. That is, it is necessary to heat the metal nanoparticles while pressurizing the heat radiating member toward the heat radiating member to pressurize the metal nanoparticles interposed therebetween. Since it is difficult to apply heat while maintaining the pressurized state in this way, this method cannot efficiently manufacture a heat dissipation unit.
  • the present specification provides a heat dissipation unit that can be efficiently manufactured and in which a heat dissipation member is connected to the heat dissipation member by a metal layer having a high melting point. Moreover, the manufacturing method of the thermal radiation unit is provided.
  • the heat dissipation unit provided in the present specification has a heat pipe, a heat radiating member, and a metal layer connecting the heat pipe and the heat radiating member, and the metal layer has a melting point of 300 ° C. or higher. .
  • the heat pipe is a heat radiating member having a sealed internal space.
  • the air pressure in the internal space increases and the heat pipe bursts.
  • the liquid sealed in the internal space of the heat pipe is water
  • the heat pipe is heated to about 300 ° C.
  • the pressure in the internal space of the heat pipe theoretically increases to about 8.5 MPa.
  • the outer wall of the heat pipe cannot withstand such high atmospheric pressure, and the heat pipe bursts.
  • the metal nanoparticle layer is heated in a state where the metal nanoparticle layer is interposed between the heat pipe and the heat radiated member.
  • the heat pipe is heated by heating the metal nanoparticle layer, the pressure in the internal space of the heat pipe rises, and the outer wall of the heat pipe in contact with the metal nanoparticle layer tends to deform toward the metal nanoparticle layer side.
  • the heat radiating member is present in the direction to be deformed, deformation of the outer wall of the heat pipe is suppressed. As a result, high pressure is applied to the metal nanoparticle layer sandwiched between the outer wall of the heat pipe and the heat radiating member.
  • the metal nanoparticle layer is heated under high pressure to form a bulk metal layer (a metal layer having a melting point of 300 ° C. or higher). For this reason, the heat pipe and the heat radiating member are firmly connected by the metal layer. In this way, the heat dissipation unit described above can be manufactured. As described above, since the metal nanoparticle layer can be heated while applying pressure without applying a strong force from the outside, the heat dissipation unit can be efficiently manufactured.
  • a thin part thinner than the outer wall of the heat pipe outside the metal layer forming region is formed on at least a part of the outer wall of the heat pipe inside the metal layer forming region where the metal layer is formed. Preferably it is.
  • the heat radiating unit having this configuration can be manufactured with a high manufacturing yield. Further, since the heat radiating member is connected to the thin portion of the heat pipe by the metal layer, heat conduction is likely to occur between the heat radiating member and the internal space of the heat pipe. Therefore, the heat radiating unit having this configuration can efficiently radiate heat from the heat radiating member.
  • any of the heat dissipation units described above may include the entire thin portion within a range where the heat pipe and the heat radiated member overlap when the heat pipe is viewed along the stacking direction of the heat pipe and the heat radiated member. preferable.
  • any of the heat dissipation units described above is in the metal layer forming region where the metal layer is formed, and when the heat pipe is viewed along the stacking direction of the heat pipe and the heat dissipation member, the heat pipe and the heat dissipation member A bending portion that is bent toward the inner side of the heat pipe may be formed on the outer wall of the heat pipe in a range where and overlap.
  • the bending part may be bent in the shape of an arch, or may be bent in a bent shape.
  • Such a flexure is easily displaced outward when the pressure in the internal space of the heat pipe rises. Therefore, when the metal nanoparticle layer is heated, a high pressure is applied to the metal nanoparticle layer between the bent portion and the heat radiating member. For this reason, a heat pipe and a heat radiating member are connected more firmly.
  • the heat radiating unit having this configuration has higher connection strength between the heat pipe and the heat radiating member.
  • the present specification provides a method for manufacturing a heat dissipation unit.
  • the metal nanoparticle layer is heated in a state where the metal nanoparticle layer is interposed between the heat pipe and the heat radiating member, thereby sintering the metal nanoparticle layer.
  • the metal nanoparticle layer when the metal nanoparticle layer is heated, the metal nanoparticle layer is pressurized by the pressure increase in the internal space of the heat pipe. For this reason, a heat pipe and a heat radiating member can be firmly connected by the metal layer which sintered the metal nanoparticle layer.
  • a thin part thinner than the periphery is formed on a part of the outer wall of the heat pipe, and the heating is performed such that the metal nanoparticle layer is in contact with the surface of the thin part. preferable.
  • a heat radiating unit having a lower thermal resistance between the heat pipe and the heat radiating member can be manufactured with a high manufacturing yield.
  • any of the manufacturing methods described above is such that when the heat pipe is viewed along the stacking direction of the heat pipe and the heat radiating member, the entire thin portion is included in the range where the heat pipe and the heat radiating member overlap. It is preferable to perform the heating.
  • a bent portion that is bent toward the inside of the heat pipe is formed on a part of the outer wall of the heat pipe, the metal nanoparticle layer is in contact with the surface of the bent portion, and
  • the heating is preferably performed so that the entire bending portion is included in a range where the heat pipe and the heat radiating member overlap when the heat pipe is viewed along the stacking direction of the heat pipe and the heat radiating member.
  • the heat pipe can be firmly connected to the heat radiating member at the bent portion.
  • FIG. 3 is a cross-sectional view of the heat dissipation unit 10 (cross-sectional view taken along the line II in FIG. 2).
  • FIG. 3 is a top view of the heat pipe 20.
  • Explanatory drawing of the manufacturing process of the thermal radiation unit Explanatory drawing of the manufacturing process in the case of joining many heat radiating units using one jig
  • the heat radiating unit includes a heat pipe, a heat radiating member, and a metal layer connecting the heat pipe and the heat radiating member.
  • the metal layer is formed by heating the metal nanoparticle layer to sinter the metal nanoparticle layer.
  • (Characteristic 2) In a state in which the metal nanoparticle layer is interposed between the heat pipe and the heat radiating member, the metal nanoparticle in a state where the relative movement of the heat pipe and the heat radiating member in a direction away from each other is restricted.
  • the metal nanoparticle layer is sintered by heating the layer.
  • the heat dissipation unit 10 includes a diode 12, a MOSFET 14, and plate-type heat pipes 20, 24, and 28.
  • the diode 12 includes a semiconductor substrate 12a mainly composed of SiC, an upper electrode 12b, and a lower electrode 12c.
  • the MOSFET 14 includes a semiconductor substrate 14a mainly composed of SiC, an upper electrode 14b, and a lower electrode 14c.
  • the MOSFET 14 includes a gate electrode (not shown).
  • the heat pipe 20 is disposed below the MOSFET 14.
  • the heat pipe 20 has an outer wall 20a and a sealed inner space 20b.
  • the outer wall 20a of the heat pipe 20 is made of copper.
  • a small amount of liquid (in this embodiment, water) is sealed in the internal space 20b.
  • a wick that transfers the liquid by capillary action is formed on the inner surface 20c of the internal space 20b.
  • the wick may be a wire mesh or a number of grooves formed on the inner surface 20c. However, when the liquid is transferred by gravity, the wick does not have to exist.
  • the upper surface 20 d of the heat pipe 20 is connected to the lower electrode 14 c of the MOSFET 14.
  • the connection structure between the lower electrode 14c and the heat pipe 20 will be described in detail.
  • each recess 22 is a region recessed in a hexagonal pyramid shape. As shown in FIG. 3, each recess 22 is formed by an outer wall 20a that is bent toward the inner space 20b. Below, the outer wall 20a of the part bent to the internal space 20b side is called the bending part 20e. The bent portion 20e is thinner than the outer wall 20a other than the bent portion 20e.
  • a dotted line 30 in FIG. 2 indicates a range that overlaps the MOSFET 14 when viewed along the direction in which the heat pipe 20 and the MOSFET 14 are stacked (that is, the vertical direction in FIG. 1).
  • the recess 22 is formed so that the entirety thereof is included in the range 30. Since the lower electrode 14c is formed on the entire lower surface of the MOSFET 14, the range 30 is equal to the range facing the lower electrode 14c.
  • a silver layer 40 is formed on the upper surface 20 d of the heat pipe 20.
  • the bending portion 20e is included in the region 40a where the silver layer 40 is formed. That is, the silver layer 40 is formed in and around the recess 22.
  • the silver layer 40 is a layer made of bulk silver.
  • the silver layer 40 is joined to the heat pipe 20 and to the lower electrode 14 c of the MOSFET 14. That is, the silver layer 40 connects the heat pipe 20 and the MOSFET 14 physically, electrically, and thermally.
  • the heat pipe 24 is disposed between the MOSFET 14 and the diode 12.
  • the heat pipe 24 has an outer wall 24a and a sealed inner space 24b. A small amount of liquid is sealed in the internal space 24b.
  • the heat pipe 24 is connected to the upper electrode 14 b of the MOSFET 14 by a connection structure substantially the same as the connection structure between the heat pipe 20 and the MOSFET 14. That is, a plurality of recesses are formed on the lower surface of the heat pipe 24.
  • Each recess has a hexagonal pyramid space shape.
  • Each recess is formed by a bent portion in which the outer wall 24a is bent toward the inner space 24b.
  • the outer wall 24a is thin at the bent portion.
  • Each recess is formed in a range overlapping with the MOSFET 14.
  • the heat pipe 24 is connected to the upper electrode 14b of the MOSFET 14 by a silver layer 42 in a region where each recess is formed.
  • the heat pipe 24 is connected to the lower electrode 12 c of the diode 12 by a connection structure that is substantially the same as the connection structure between the heat pipe 20 and the MOSFET 14. That is, a plurality of recesses are formed on the upper surface of the heat pipe 24.
  • Each recess has a hexagonal pyramid space shape.
  • Each recess is formed by a bent portion in which the outer wall 24a is bent toward the inner space 24b.
  • the outer wall 24a is thin at the bent portion.
  • Each recess is formed in a range overlapping with the diode 12.
  • the heat pipe 24 is connected to the lower electrode 12c of the diode 12 by a silver layer 44 in the region where each recess is formed.
  • the heat pipe 28 is disposed on the upper side of the diode 12.
  • the heat pipe 28 has an outer wall 28a and a sealed inner space 28b. A small amount of liquid is sealed in the internal space 28b.
  • the heat pipe 28 is connected to the upper electrode 12 b of the diode 12 by a connection structure substantially the same as the connection structure between the heat pipe 20 and the MOSFET 14. That is, a plurality of recesses are formed on the lower surface of the heat pipe 28.
  • Each recess has a hexagonal pyramid space shape.
  • Each recess is formed by a bent portion in which the outer wall 28a is bent toward the inner space 28b. At the bent portion, the outer wall 28a is thin.
  • Each recess is formed in a range overlapping with the diode 12.
  • the heat pipe 28 is connected to the upper electrode 12b of the diode 12 by a silver layer 46 in a region where each recess is formed.
  • the operation of dissipating heat from the diode 12 and the MOSFET 14 by the heat radiating unit 10 will be described.
  • the MOSFET 14 When a current flows through the MOSFET 14, the MOSFET 14 generates heat.
  • the heat generated in the MOSFET 14 is transmitted to the liquid in the internal space 20b of the heat pipe 20 through the silver layer 40 and the outer wall 20a of the heat pipe 20.
  • the liquid in the heat pipe 20 in contact with the outer wall 20a in the region 40a (see FIG. 3) where the silver layer 40 is formed is vaporized, and the outer wall 20a in the region 40a is cooled.
  • the vaporized gas flows to a position away from the MOSFET 14, where it is cooled and liquefied.
  • the liquid is returned to a position in contact with the outer wall 20a in the region 40a where the silver layer 40 is formed by wick capillary phenomenon or the like, and the returned liquid is vaporized again there. Therefore, the outer wall 20a in the region 40a where the silver layer 40 is formed is continuously cooled by the heat of vaporization, and the MOSFET 14 is cooled.
  • region 40a in which the silver layer 40 is formed is thinner than the outer wall 20a outside the area
  • the heat generated in the MOSFET 14 is also transmitted to the liquid inside the heat pipe 24 via the silver layer 42 and the outer wall 24 a of the heat pipe 24. Therefore, the MOSFET 14 is also cooled by the heat pipe 24. Thus, the MOSFET 14 is cooled by the two heat pipes 20 and 24.
  • the diode 12 when a current flows through the diode 12, the diode 12 generates heat.
  • the heat generated in the diode 12 is transmitted to the liquid inside the heat pipe 28 via the silver layer 46 and the outer wall 28 a of the heat pipe 28. Therefore, the diode 12 is cooled by the heat pipe 28. Since the bent portion is thin, the heat generated by the diode 12 is easily transferred to the liquid inside the heat pipe 28. Therefore, the diode 12 is efficiently cooled.
  • the heat generated in the diode 12 is also transmitted to the liquid inside the heat pipe 24 via the silver layer 44 and the outer wall 24 a of the heat pipe 24. Therefore, the diode 12 is also cooled by the heat pipe 24.
  • the diode 12 is cooled by the two heat pipes 24 and 28.
  • the heat pipe 20, the MOSFET 14, the heat pipe 24, the diode 12, and the heat pipe 28 are stacked with the silver nanoparticle layers 50, 52, 54, and 56 interposed.
  • the silver nanoparticle layers 50, 52, 54, and 56 are layers formed by applying a paste in which silver nanoparticles are dispersed in an organic or inorganic binder, and have viscosity.
  • the average particle diameter of the silver nanoparticles used at this time is preferably 100 nm or less.
  • the silver nanoparticle layers 50, 52, 54, and 56 are formed in and around the recesses of the heat pipes.
  • the concave portion 22 of the heat pipe 20 and the concave portion of the lower surface of the heat pipe 24 are disposed within the range overlapping with the MOSFET 14, and the concave portion of the upper surface of the heat pipe 24 and the concave portion of the heat pipe 28 are disposed within the range overlapping with the diode 12.
  • the heat pipe 20, the MOSFET 14, the heat pipe 24, the diode 12, and the heat pipe 28 are stacked.
  • the laminated body 60 of the heat pipe 20, the MOSFET 14, the heat pipe 24, the diode 12, and the heat pipe 28 is formed, the laminated body 60 is sandwiched between the support plates 62 and 64 in the lamination direction. Then, the support plates 62 and 64 are connected by screws 66 and 68. In this manner, the relative movement of the heat pipe 20, the MOSFET 14, the heat pipe 24, the diode 12, and the heat pipe 28 in a direction away from each other is restricted. In this state, the laminate 60 is heated to 200 ° C. to 300 ° C. by a heating furnace. Then, the liquid inside the heat pipes 20, 24, 28 is vaporized, and the heat pipes 20, 24, 28 are slightly expanded.
  • the silver nanoparticle layers 50, 52, 54, and 56 are pressurized by the expansion of the heat pipes 20, 24, and 28. That is, the silver nanoparticle layers 50, 52, 54, and 56 are heated in a pressurized state. Then, the silver nanoparticles in the silver nanoparticle layers 50, 52, 54, and 56 are joined together, and the silver nanoparticle layers 50, 52, 54, and 56 are sintered. As a result, the silver nanoparticle layers 50, 52, 54, and 56 become bulky silver layers 40, 42, 44, and 46 (see FIG. 1).
  • an alloy layer of silver and a constituent metal (copper in this embodiment) of the outer wall of the heat pipe is formed at the boundary between each silver layer and the outer wall of the heat pipe.
  • the silver layer and the outer wall of the heat pipe are joined.
  • an alloy layer of silver and a constituent metal of the electrode of the semiconductor device is formed at the boundary between each silver layer and the electrode of the semiconductor device.
  • the alloy layer joins the silver layer and the electrode of the semiconductor device. Therefore, the bulked silver layer 40 is bonded to the upper surface of the heat pipe 20 and to the lower electrode 14 c of the MOSFET 14. That is, the upper surface of the heat pipe 20 and the lower electrode 14 c of the MOSFET 14 are connected by the silver layer 40.
  • the upper electrode 14b of the MOSFET 14 and the lower surface of the heat pipe 24 are connected by the silver layer 42
  • the upper surface of the heat pipe 24 and the lower electrode 12c of the diode 12 are connected by the silver layer 44
  • the upper electrode 12b of the diode 12 The lower surface of the heat pipe 28 is connected by a silver layer 46.
  • the silver nanoparticle layer can be obtained simply by heating the stacked body 60 in a state where the heat pipe 20, the MOSFET 14, the heat pipe 24, the diode 12, and the heat pipe 28 are restricted from moving relative to each other. 50, 52, 54, 56 can be pressurized. Therefore, a force for sandwiching the laminate 60 between the support plates 62 and 64 (that is, a force for pressing the laminate 60 from the outside) is hardly required. For this reason, the heat radiation unit 10 can be manufactured with a simple jig such as the support plates 62 and 64 and the screws 66 and 68 described above. That is, according to this manufacturing method, the heat radiating unit 10 can be manufactured efficiently.
  • the bent portion 20e of the outer wall 20a of the heat pipe 20 that is bent toward the inner space 20b easily deforms outward when the atmospheric pressure in the inner space 20b rises.
  • the bending part 20e is thin and the bending part 20e also becomes easy to deform
  • the bent portion 20e is supported from the outside by the silver nanoparticle layer 50 (in particular, the silver nanoparticle layer 50 in the recess 22) and the MOSFET 14.
  • the outward deformation of the bent portion 20e is suppressed.
  • the heat radiating unit 10 can be manufactured with a high manufacturing yield.
  • the heat radiating member (diode 12 or MOSFET 14) is connected to the heat pipe (20, 24, 28) by the metal layer having a melting point of 300 ° C. or higher. It is possible to efficiently manufacture the heat dissipation unit.
  • a plurality of laminated bodies 60 may be sandwiched between support plates 62 and 64 and heated. Since the silver nanoparticle layer is pressurized by the expansion of each heat pipe, even when the plurality of laminated bodies 60 are sandwiched between the pair of support plates 62 and 64 and heated as described above, each laminated body 60 is sufficiently pressurized. be able to. Moreover, according to such a structure, the thermal radiation unit 10 can be manufactured more efficiently.
  • the bent portion 20e of the outer wall 20a is bent toward the inner space 20b side and is thinner than the outer wall 20a other than the bent portion 20e.
  • a thin portion 20f that is not bent and is thinner than the outer wall 20a outside the region 40a may be formed in the region 40a where the silver layer 40 is formed.
  • Such a thin portion 20f is easily deformed even if it is not bent. Therefore, by providing the thin portion 20f, the silver nanoparticle layer in contact with the thin portion 20f can be effectively pressurized during heating in the manufacturing process, and the heat pipe 20 and the MOSFET 14 can be firmly connected. Further, in FIG.
  • a thin portion is formed by forming a recess on the outer surface (upper surface 20d) of the outer wall 20a.
  • a recess is formed on the inner surface of the outer wall 20a.
  • the thin part 20f may be formed. Even in the configuration of FIG. 7, the heat pipe 20 and the MOSFET 14 can be firmly connected. Further, as shown in FIG. 8, the thin portion 20 f may be formed in a wider range than the MOSFET 14. Even with such a configuration, it is possible to efficiently pressurize the silver layer 40 between the thin portion 20 f and the MOSFET 14. Further, if the silver layer 40 is formed on the thin portion 20f, the thin portion 20f can be supported by the MOSFET 14 and the silver layer 40 during heating in the manufacturing process, so that the thin portion 20f can be prevented from being damaged.
  • the bent portion 20e is formed thin.
  • the bent portion 20e may not be thin.
  • the thickness of the bent portion 20e is equal to the thickness of the outer wall 20a other than the bent portion 20e. Even if the outer wall 20a is not thin, it is easily deformed if it is bent. Therefore, even if the thin bending part 20e is provided, the silver nanoparticle layer 40 in contact with the bending part 20e can be effectively pressurized during heating in the manufacturing process, and the heat pipe 20 and the MOSFET 14 can be firmly connected. it can.
  • the bending part 20e was formed densely, the bending part 20e may be formed discretely.
  • silver nanoparticles are used as the metal nanoparticles, but other metal nanoparticles may be used.
  • the Example mentioned above demonstrated the thermal radiation unit which connected the diode and MOSFET to the heat pipe.
  • other semiconductor devices and other heat radiating members such as heat conducting members (for example, copper plates) may be connected to the heat pipe.
  • the outer wall of the heat pipe has a thickness of 0.1 mm or more and 3.0 mm or less in a region other than the thin portion. This is because if the thickness of the outer wall of the heat pipe is less than 0.1 mm, the heat pipe may be damaged (exploded) during heating in the manufacturing process of the heat dissipation unit. In addition, if the thickness of the outer wall of the heat pipe is larger than 3.0 mm, heat conduction between the inside and outside of the heat pipe is difficult to occur, and the cooling effect by the liquid inside the heat pipe is sufficiently generated. This is because they cannot.
  • the outer wall of the heat pipe is preferably made of a material that has high thermal conductivity and can be easily bonded to metal nanoparticles, such as copper, aluminum, nickel, steel, and stainless steel.
  • the electrode of the semiconductor device is made of a material having high thermal conductivity and being easily bonded to metal nanoparticles, such as gold, copper, nickel, aluminum, tungsten, and AlSi.
  • Heat dissipation unit 12 Diode 14: MOSFET 20: Heat pipe 20a: Outer wall 20b: Internal space 20e: Deflection 22: Recess 24: Heat pipe 28: Heat pipe 40: Silver layer 42: Silver layer 44: Silver layer 46: Silver layer

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Abstract

A heat radiation unit (10) is provided with a heat pipe (20), a member (14) to which heat is radiated, and a metallic layer (40) which connects the heat pipe (20) and the member (14) to which heat is radiated, and the heat radiation unit (10) is characterized in that the metallic layer (40) has a melting point which is 300˚C or higher. The metallic layer (40) is formed by heating a metallic nanoparticle layer.

Description

放熱ユニット及びその製造方法Radiation unit and manufacturing method thereof
　本明細書に開示の技術は、ヒートパイプを被放熱部材（例えば、発熱体や、熱伝導部材）に接続した放熱ユニットに関する。 The technology disclosed in this specification relates to a heat radiating unit in which a heat pipe is connected to a heat radiating member (for example, a heating element or a heat conducting member).
　日本国特許公開公報２００４－１３０３７１には、金属ナノ粒子を用いて２つの部材を接続する技術が開示されている。なお、本明細書において、金属ナノ粒子とは、粒径が１００ｎｍ以下の金属の粒子を意味する。特許文献１の技術では、２つの部材の間に銀ナノ粒子層を配置し、次に、これらの部材を２００℃から３００℃に加熱する。加熱によって、銀ナノ粒子層が焼結する。すなわち、銀ナノ粒子層中の銀ナノ粒子が互いに接合する。これによって、バルク状の銀層が形成される。また、銀ナノ粒子は、加熱により前記各部材とも接合される。したがって、形成されるバルク状の銀層は、各部材と接合している。すなわち、バルク状の銀層によって、２つの部材が互いに接続される。 Japanese Patent Publication No. 2004-130371 discloses a technique for connecting two members using metal nanoparticles. In the present specification, the metal nanoparticles mean metal particles having a particle size of 100 nm or less. In the technique of Patent Document 1, a silver nanoparticle layer is disposed between two members, and then these members are heated to 200 ° C. to 300 ° C. The silver nanoparticle layer is sintered by heating. That is, the silver nanoparticles in the silver nanoparticle layer are joined together. Thereby, a bulky silver layer is formed. The silver nanoparticles are also bonded to the members by heating. Accordingly, the formed bulk silver layer is bonded to each member. That is, the two members are connected to each other by the bulk silver layer.
　被放熱部材を放熱部材に接続することで、被放熱部材の熱を放熱部材へ逃がす放熱ユニットが知られている。放熱ユニットは高温になるので、高い融点を有する金属層により被放熱部材を放熱部材に接続することが好ましい。上述した金属ナノ粒子を用いて２つの部材を接続する技術によれば、比較的低い温度（上記の例では、２００℃から３００℃）での熱処理することで、３００度以上の高い融点を有する金属層（例えば、約９６０℃の融点を有する銀）によって被放熱部材と放熱部材とを接続することができる。しかしながら、この製造方法では、金属ナノ粒子に高い圧力を加えた状態で金属ナノ粒子を加熱しなければ、高い接続強度を得られないという問題があった。すなわち、被放熱部材を放熱部材に向けて押し付けることによってこれらの間に介在する金属ナノ粒子を加圧しながら、金属ナノ粒子を加熱する必要があった。このように加圧した状態を維持しながら熱を加えることは困難であるため、この方法では放熱ユニットを効率的に製造することができなかった。 A heat radiating unit that releases heat from a heat radiating member to the heat radiating member by connecting the heat radiating member to the heat radiating member is known. Since the heat radiating unit becomes high temperature, it is preferable to connect the heat radiating member to the heat radiating member with a metal layer having a high melting point. According to the technique of connecting two members using the metal nanoparticles described above, a high melting point of 300 ° C. or higher is obtained by heat treatment at a relatively low temperature (in the above example, 200 ° C. to 300 ° C.). The heat radiating member and the heat radiating member can be connected by a metal layer (for example, silver having a melting point of about 960 ° C.). However, this manufacturing method has a problem that high connection strength cannot be obtained unless the metal nanoparticles are heated in a state where a high pressure is applied to the metal nanoparticles. That is, it is necessary to heat the metal nanoparticles while pressurizing the heat radiating member toward the heat radiating member to pressurize the metal nanoparticles interposed therebetween. Since it is difficult to apply heat while maintaining the pressurized state in this way, this method cannot efficiently manufacture a heat dissipation unit.
　したがって、本明細書では、効率的に製造することが可能であるとともに、高い融点を有する金属層によって被放熱部材が放熱部材に接続されている放熱ユニットを提供する。また、その放熱ユニットの製造方法を提供する。 Therefore, the present specification provides a heat dissipation unit that can be efficiently manufactured and in which a heat dissipation member is connected to the heat dissipation member by a metal layer having a high melting point. Moreover, the manufacturing method of the thermal radiation unit is provided.
　本明細書が提供する放熱ユニットは、ヒートパイプと、被放熱部材と、ヒートパイプと被放熱部材とを接続している金属層を有しており、金属層が、３００℃以上の融点を有する。 The heat dissipation unit provided in the present specification has a heat pipe, a heat radiating member, and a metal layer connecting the heat pipe and the heat radiating member, and the metal layer has a melting point of 300 ° C. or higher. .
　なお、ヒートパイプは、密閉された内部空間を有する放熱部材である。ヒートパイプを３００℃以上に加熱すると、内部空間の気圧が高くなってヒートパイプが破裂する。例えば、ヒートパイプの内部空間に封入されている液体が水である場合には、ヒートパイプを約３００℃まで加熱すると、理論上はヒートパイプの内部空間の気圧は約８．５ＭＰａまで上昇する。実際には、ヒートパイプの外壁はこのような高気圧に耐えられず、ヒートパイプが破裂する。３００℃以上に加熱しても破裂しないヒートパイプは存在しない。これは、このような高温でも破裂しないためにはヒートパイプの外壁を極めて厚くする必要があるが、外壁を厚くするとヒートパイプの放熱性能が極端に低下し、実用性が無いためである。したがって、上記の３００℃以上の融点を有する金属層は、ヒートパイプに対して溶接されたものではない。この金属層は、金属ナノ粒子層を焼結することで形成されたものである。 The heat pipe is a heat radiating member having a sealed internal space. When the heat pipe is heated to 300 ° C. or higher, the air pressure in the internal space increases and the heat pipe bursts. For example, when the liquid sealed in the internal space of the heat pipe is water, when the heat pipe is heated to about 300 ° C., the pressure in the internal space of the heat pipe theoretically increases to about 8.5 MPa. Actually, the outer wall of the heat pipe cannot withstand such high atmospheric pressure, and the heat pipe bursts. There is no heat pipe that does not burst even when heated above 300 ° C. This is because it is necessary to make the outer wall of the heat pipe extremely thick so that it does not rupture even at such a high temperature. Therefore, the metal layer having the melting point of 300 ° C. or higher is not welded to the heat pipe. This metal layer is formed by sintering a metal nanoparticle layer.
　この放熱ユニットを製造するには、ヒートパイプと被放熱部材との間に金属ナノ粒子層を介在させた状態で、金属ナノ粒子層を加熱する。金属ナノ粒子層の加熱によってヒートパイプが加熱されると、ヒートパイプの内部空間の圧力が上昇して、金属ナノ粒子層と接しているヒートパイプの外壁が、金属ナノ粒子層側に変形しようとする。しかしながら、その変形しようとする方向には被放熱部材が存在しているため、ヒートパイプの外壁の変形が抑制される。その結果、ヒートパイプの外壁と被放熱部材との間に挟まれた金属ナノ粒子層に高い圧力が加わる。これによって、金属ナノ粒子層が、高圧力下で加熱され、バルク状の金属層（３００℃以上の融点を有する金属層）となる。このため、金属層によって、ヒートパイプと被放熱部材とが強固に接続される。このようにして上述した放熱ユニットを製造することができる。以上に説明したように、外部から強い力を加えなくても、金属ナノ粒子層を加圧しながら加熱することができるので、この放熱ユニットは効率的に製造され得る。 To manufacture this heat dissipation unit, the metal nanoparticle layer is heated in a state where the metal nanoparticle layer is interposed between the heat pipe and the heat radiated member. When the heat pipe is heated by heating the metal nanoparticle layer, the pressure in the internal space of the heat pipe rises, and the outer wall of the heat pipe in contact with the metal nanoparticle layer tends to deform toward the metal nanoparticle layer side. To do. However, since the heat radiating member is present in the direction to be deformed, deformation of the outer wall of the heat pipe is suppressed. As a result, high pressure is applied to the metal nanoparticle layer sandwiched between the outer wall of the heat pipe and the heat radiating member. As a result, the metal nanoparticle layer is heated under high pressure to form a bulk metal layer (a metal layer having a melting point of 300 ° C. or higher). For this reason, the heat pipe and the heat radiating member are firmly connected by the metal layer. In this way, the heat dissipation unit described above can be manufactured. As described above, since the metal nanoparticle layer can be heated while applying pressure without applying a strong force from the outside, the heat dissipation unit can be efficiently manufactured.
　ヒートパイプの外壁が薄いほど、ヒートパイプの内部空間と被放熱部材との間の熱伝導が促進されるため、被放熱部材が放熱され易くなる。しかしながら、ヒートパイプの外壁を薄くすると、金属ナノ粒子層の加熱時にヒートパイプの内部空間の圧力が上昇することによってヒートパイプが破裂し易くなり、放熱ユニットの製造歩留まりが低下する。 As the outer wall of the heat pipe is thinner, heat conduction between the internal space of the heat pipe and the member to be radiated is promoted, so that the member to be radiated is easily radiated. However, if the outer wall of the heat pipe is thinned, the pressure in the internal space of the heat pipe increases when the metal nanoparticle layer is heated, so that the heat pipe is easily ruptured, and the manufacturing yield of the heat radiating unit decreases.
　したがって、上述した放熱ユニットは、金属層が形成されている金属層形成領域内のヒートパイプの外壁の少なくとも一部に、金属層形成領域外のヒートパイプの外壁よりも薄い薄肉部が形成されていることが好ましい。 Therefore, in the heat dissipation unit described above, a thin part thinner than the outer wall of the heat pipe outside the metal layer forming region is formed on at least a part of the outer wall of the heat pipe inside the metal layer forming region where the metal layer is formed. Preferably it is.
　このような構成によれば、金属層形成領域外のヒートパイプの外壁が厚いので、金属ナノ粒子層の加熱時に、この外壁が破損することが防止される。また、薄肉部が形成されている金属層形成領域は、加熱時に被放熱部材と金属ナノ粒子層によって支えられる。これによって、薄肉部の破損も防止される。したがって、この構成の放熱ユニットは、高い製造歩留まりで製造され得る。また、金属層によって被放熱部材がヒートパイプの薄肉部に接続されるので、被放熱部材とヒートパイプの内部空間との間で熱伝導が生じ易い。したがって、この構成の放熱ユニットは、効率的に被放熱部材から放熱することができる。 According to such a configuration, since the outer wall of the heat pipe outside the metal layer forming region is thick, the outer wall is prevented from being damaged when the metal nanoparticle layer is heated. Further, the metal layer forming region where the thin portion is formed is supported by the heat radiating member and the metal nanoparticle layer during heating. As a result, damage to the thin portion is also prevented. Therefore, the heat radiating unit having this configuration can be manufactured with a high manufacturing yield. Further, since the heat radiating member is connected to the thin portion of the heat pipe by the metal layer, heat conduction is likely to occur between the heat radiating member and the internal space of the heat pipe. Therefore, the heat radiating unit having this configuration can efficiently radiate heat from the heat radiating member.
　上述した何れかの放熱ユニットは、ヒートパイプと被放熱部材の積層方向に沿ってヒートパイプを見たときにヒートパイプと被放熱部材とが重なる範囲内に薄肉部全体が含まれていることが好ましい。 Any of the heat dissipation units described above may include the entire thin portion within a range where the heat pipe and the heat radiated member overlap when the heat pipe is viewed along the stacking direction of the heat pipe and the heat radiated member. preferable.
　上述した何れかの放熱ユニットは、金属層が形成されている金属層形成領域内であって、ヒートパイプと被放熱部材の積層方向に沿ってヒートパイプを見たときにヒートパイプと被放熱部材とが重なる範囲内のヒートパイプの外壁に、ヒートパイプの内側に向かって撓んでいる撓み部が形成されていてもよい。 Any of the heat dissipation units described above is in the metal layer forming region where the metal layer is formed, and when the heat pipe is viewed along the stacking direction of the heat pipe and the heat dissipation member, the heat pipe and the heat dissipation member A bending portion that is bent toward the inner side of the heat pipe may be formed on the outer wall of the heat pipe in a range where and overlap.
　なお、撓み部は、アーチ状に撓んでいてもよいし、折れ曲がった形状に撓んでいてもよい。このような撓み部は、ヒートパイプの内部空間の圧力上昇時に外側に変位し易い。したがって、金属ナノ粒子層の加熱時に、撓み部と被放熱部材の間の金属ナノ粒子層に高い圧力が加わる。このため、ヒートパイプと被放熱部材がより強固に接続される。この構成の放熱ユニットは、ヒートパイプと被放熱部材との接続強度がより高い。 In addition, the bending part may be bent in the shape of an arch, or may be bent in a bent shape. Such a flexure is easily displaced outward when the pressure in the internal space of the heat pipe rises. Therefore, when the metal nanoparticle layer is heated, a high pressure is applied to the metal nanoparticle layer between the bent portion and the heat radiating member. For this reason, a heat pipe and a heat radiating member are connected more firmly. The heat radiating unit having this configuration has higher connection strength between the heat pipe and the heat radiating member.
　また、本明細書は放熱ユニットの製造方法を提供する。この製造方法では、ヒートパイプと被放熱部材との間に金属ナノ粒子層を介在させた状態で、金属ナノ粒子層を加熱することで、金属ナノ粒子層を焼結させる。 Also, the present specification provides a method for manufacturing a heat dissipation unit. In this manufacturing method, the metal nanoparticle layer is heated in a state where the metal nanoparticle layer is interposed between the heat pipe and the heat radiating member, thereby sintering the metal nanoparticle layer.
　この製造方法によれば、金属ナノ粒子層の加熱時に、ヒートパイプの内部空間の圧力上昇によって金属ナノ粒子層が加圧される。このため、金属ナノ粒子層を焼結させた金属層によってヒートパイプと被放熱部材を強固に接続することができる。 According to this manufacturing method, when the metal nanoparticle layer is heated, the metal nanoparticle layer is pressurized by the pressure increase in the internal space of the heat pipe. For this reason, a heat pipe and a heat radiating member can be firmly connected by the metal layer which sintered the metal nanoparticle layer.
　上述した製造方法は、ヒートパイプの外壁の一部に、その周囲よりも薄い薄肉部が形成されており、薄肉部の表面に金属ナノ粒子層が接触するようにして、前記加熱を行うことが好ましい。 In the manufacturing method described above, a thin part thinner than the periphery is formed on a part of the outer wall of the heat pipe, and the heating is performed such that the metal nanoparticle layer is in contact with the surface of the thin part. preferable.
　この製造方法によれば、ヒートパイプと被放熱部材との間の熱抵抗がより低い放熱ユニットを、高い製造歩留まりで製造することができる。 According to this manufacturing method, a heat radiating unit having a lower thermal resistance between the heat pipe and the heat radiating member can be manufactured with a high manufacturing yield.
　上述した何れかの製造方法は、ヒートパイプと被放熱部材の積層方向に沿ってヒートパイプを見たときにヒートパイプと被放熱部材とが重なる範囲内に薄肉部全体が含まれるようにして、前記加熱を行うことが好ましい。 Any of the manufacturing methods described above is such that when the heat pipe is viewed along the stacking direction of the heat pipe and the heat radiating member, the entire thin portion is included in the range where the heat pipe and the heat radiating member overlap. It is preferable to perform the heating.
　上述した何れかの製造方法は、ヒートパイプの外壁の一部に、ヒートパイプの内側に向かって撓んでいる撓み部が形成されており、撓み部の表面に金属ナノ粒子層が接触し、かつ、ヒートパイプと被放熱部材の積層方向に沿ってヒートパイプを見たときにヒートパイプと被放熱部材とが重なる範囲内に撓み部全体が含まれるようにして、前記加熱を行うことが好ましい。 In any one of the manufacturing methods described above, a bent portion that is bent toward the inside of the heat pipe is formed on a part of the outer wall of the heat pipe, the metal nanoparticle layer is in contact with the surface of the bent portion, and The heating is preferably performed so that the entire bending portion is included in a range where the heat pipe and the heat radiating member overlap when the heat pipe is viewed along the stacking direction of the heat pipe and the heat radiating member.
　この製造方法によれば、撓み部においてヒートパイプを被放熱部材により強固に接続することができる。 According to this manufacturing method, the heat pipe can be firmly connected to the heat radiating member at the bent portion.
放熱ユニット１０の断面図（図２のＩ－Ｉ線における断面図）。FIG. 3 is a cross-sectional view of the heat dissipation unit 10 (cross-sectional view taken along the line II in FIG. 2). ヒートパイプ２０の上面図。FIG. 3 is a top view of the heat pipe 20. ヒートパイプ２０とＭＯＳＦＥＴ１４との接続部分の拡大断面図。The expanded sectional view of the connection part of the heat pipe 20 and MOSFET14. 放熱ユニット１０の製造工程の説明図。Explanatory drawing of the manufacturing process of the thermal radiation unit. 多数の放熱ユニットを一つの治具を用いて接合する場合の製造工程の説明図。Explanatory drawing of the manufacturing process in the case of joining many heat radiating units using one jig | tool. 第１変形例の放熱ユニット１０の図３に対応する拡大断面図。The expanded sectional view corresponding to FIG. 3 of the thermal radiation unit 10 of a 1st modification. 第２変形例の放熱ユニット１０の図３に対応する拡大断面図。The expanded sectional view corresponding to FIG. 3 of the thermal radiation unit 10 of a 2nd modification. 第３変形例の放熱ユニット１０の図３に対応する拡大断面図。The expanded sectional view corresponding to FIG. 3 of the thermal radiation unit 10 of a 3rd modification. 第４変形例の放熱ユニット１０の図３に対応する拡大断面図。The expanded sectional view corresponding to FIG. 3 of the thermal radiation unit 10 of a 4th modification.
　以下に説明する実施例の製造方法の特徴について列記する。
（特徴１）　放熱ユニットは、ヒートパイプと、被放熱部材と、ヒートパイプと被放熱部材とを接続している金属層を有する。金属層は、金属ナノ粒子層を加熱して金属ナノ粒子層を焼結させることで形成されたものである。
（特徴２）　ヒートパイプと被放熱部材との間に金属ナノ粒子層を介在させた状態で、ヒートパイプと被放熱部材とが互いに離反する方向に相対移動することを規制した状態で金属ナノ粒子層を加熱することで、金属ナノ粒子層を焼結させる。 The features of the manufacturing methods of the embodiments described below are listed.
(Characteristic 1) The heat radiating unit includes a heat pipe, a heat radiating member, and a metal layer connecting the heat pipe and the heat radiating member. The metal layer is formed by heating the metal nanoparticle layer to sinter the metal nanoparticle layer.
(Characteristic 2) In a state in which the metal nanoparticle layer is interposed between the heat pipe and the heat radiating member, the metal nanoparticle in a state where the relative movement of the heat pipe and the heat radiating member in a direction away from each other is restricted. The metal nanoparticle layer is sintered by heating the layer.
　図１に示すように、実施例に係る放熱ユニット１０は、ダイオード１２と、ＭＯＳＦＥＴ１４と、板型のヒートパイプ２０、２４、２８を備えている。 As shown in FIG. 1, the heat dissipation unit 10 according to the embodiment includes a diode 12, a MOSFET 14, and plate- type heat pipes 20, 24, and 28.
　ダイオード１２は、主にＳｉＣにより構成された半導体基板１２ａと、上部電極１２ｂと、下部電極１２ｃを備えている。 The diode 12 includes a semiconductor substrate 12a mainly composed of SiC, an upper electrode 12b, and a lower electrode 12c.
　ＭＯＳＦＥＴ１４は、主にＳｉＣにより構成された半導体基板１４ａと、上部電極１４ｂと、下部電極１４ｃを備えている。また、ＭＯＳＦＥＴ１４は、図示しないゲート電極を備えている。 The MOSFET 14 includes a semiconductor substrate 14a mainly composed of SiC, an upper electrode 14b, and a lower electrode 14c. The MOSFET 14 includes a gate electrode (not shown).
　ヒートパイプ２０は、ＭＯＳＦＥＴ１４の下側に配置されている。ヒートパイプ２０は、外壁２０ａと、密閉された内部空間２０ｂを有している。ヒートパイプ２０の外壁２０ａは、銅により構成されている。内部空間２０ｂ内には、少量の液体（本実施例では、水）が封入されている。内部空間２０ｂの内面２０ｃには、毛細管現象によって前記液体を移送するウィックが形成されている。ウィックは、金網であってもよいし、内面２０ｃに形成された多数の溝であってもよい。但し、重力によって前記液体を移送する場合には、ウィックが存在していなくてもよい。ヒートパイプ２０の上面２０ｄは、ＭＯＳＦＥＴ１４の下部電極１４ｃに接続されている。以下、下部電極１４ｃとヒートパイプ２０の間の接続構造について詳細に説明する。図２、３に示すように、ヒートパイプ２０の上面２０ｄには、複数の凹部２２が形成されている。各凹部２２は、六角錐状に凹んだ領域である。図３に示すように、各凹部２２は、内部空間２０ｂ側に撓んだ外壁２０ａによって形成されている。以下では、内部空間２０ｂ側に撓んでいる部分の外壁２０ａを、撓み部２０ｅという。撓み部２０ｅは、撓み部２０ｅ以外の外壁２０ａよりも薄い。図２の点線３０は、ヒートパイプ２０とＭＯＳＦＥＴ１４とが積層されている方向（すなわち、図１の上下方向）に沿って見たときにＭＯＳＦＥＴ１４と重なる範囲を示している。図示するように、凹部２２は、これらの全体が範囲３０内に含まれるように形成されている。なお、ＭＯＳＦＥＴ１４の下面全体に下部電極１４ｃが形成されているので、範囲３０は、下部電極１４ｃと対向している範囲と等しい。図３に示すように、ヒートパイプ２０の上面２０ｄには、銀層４０が形成されている。撓み部２０ｅは、銀層４０が形成されている領域４０ａ内に含まれている。すなわち、凹部２２内とその周囲に銀層４０が形成されている。銀層４０は、バルク状の銀により構成された層である。銀層４０は、ヒートパイプ２０と接合されているとともに、ＭＯＳＦＥＴ１４の下部電極１４ｃと接合されている。すなわち、銀層４０は、ヒートパイプ２０とＭＯＳＦＥＴ１４を物理的、電気的、及び、熱的に接続している。 The heat pipe 20 is disposed below the MOSFET 14. The heat pipe 20 has an outer wall 20a and a sealed inner space 20b. The outer wall 20a of the heat pipe 20 is made of copper. A small amount of liquid (in this embodiment, water) is sealed in the internal space 20b. A wick that transfers the liquid by capillary action is formed on the inner surface 20c of the internal space 20b. The wick may be a wire mesh or a number of grooves formed on the inner surface 20c. However, when the liquid is transferred by gravity, the wick does not have to exist. The upper surface 20 d of the heat pipe 20 is connected to the lower electrode 14 c of the MOSFET 14. Hereinafter, the connection structure between the lower electrode 14c and the heat pipe 20 will be described in detail. As shown in FIGS. 2 and 3, a plurality of recesses 22 are formed on the upper surface 20 d of the heat pipe 20. Each recess 22 is a region recessed in a hexagonal pyramid shape. As shown in FIG. 3, each recess 22 is formed by an outer wall 20a that is bent toward the inner space 20b. Below, the outer wall 20a of the part bent to the internal space 20b side is called the bending part 20e. The bent portion 20e is thinner than the outer wall 20a other than the bent portion 20e. A dotted line 30 in FIG. 2 indicates a range that overlaps the MOSFET 14 when viewed along the direction in which the heat pipe 20 and the MOSFET 14 are stacked (that is, the vertical direction in FIG. 1). As shown in the figure, the recess 22 is formed so that the entirety thereof is included in the range 30. Since the lower electrode 14c is formed on the entire lower surface of the MOSFET 14, the range 30 is equal to the range facing the lower electrode 14c. As shown in FIG. 3, a silver layer 40 is formed on the upper surface 20 d of the heat pipe 20. The bending portion 20e is included in the region 40a where the silver layer 40 is formed. That is, the silver layer 40 is formed in and around the recess 22. The silver layer 40 is a layer made of bulk silver. The silver layer 40 is joined to the heat pipe 20 and to the lower electrode 14 c of the MOSFET 14. That is, the silver layer 40 connects the heat pipe 20 and the MOSFET 14 physically, electrically, and thermally.
　ヒートパイプ２４は、ＭＯＳＦＥＴ１４とダイオード１２の間に配置されている。ヒートパイプ２４は、外壁２４ａと、密閉された内部空間２４ｂを有している。内部空間２４ｂ内には、少量の液体が封入されている。ヒートパイプ２４は、ヒートパイプ２０とＭＯＳＦＥＴ１４の間の接続構造と略同じ接続構造によって、ＭＯＳＦＥＴ１４の上部電極１４ｂに接続されている。すなわち、ヒートパイプ２４の下面には、複数の凹部が形成されている。各凹部は、六角錐状の空間形状を有している。各凹部は、外壁２４ａが内部空間２４ｂ側に撓んでいる撓み部により形成されている。撓み部では、外壁２４ａが薄くなっている。各凹部は、ＭＯＳＦＥＴ１４と重なる範囲内に形成されている。ヒートパイプ２４は、各凹部が形成されている領域において、銀層４２によってＭＯＳＦＥＴ１４の上部電極１４ｂに接続されている。また、ヒートパイプ２４は、ヒートパイプ２０とＭＯＳＦＥＴ１４の間の接続構造との略同じ接続構造によって、ダイオード１２の下部電極１２ｃに接続されている。すなわち、ヒートパイプ２４の上面には、複数の凹部が形成されている。各凹部は、六角錐状の空間形状を有している。各凹部は、外壁２４ａが内部空間２４ｂ側に撓んでいる撓み部により形成されている。撓み部では、外壁２４ａが薄くなっている。各凹部は、ダイオード１２と重なる範囲内に形成されている。ヒートパイプ２４は、各凹部が形成されている領域において、銀層４４によってダイオード１２の下部電極１２ｃに接続されている。 The heat pipe 24 is disposed between the MOSFET 14 and the diode 12. The heat pipe 24 has an outer wall 24a and a sealed inner space 24b. A small amount of liquid is sealed in the internal space 24b. The heat pipe 24 is connected to the upper electrode 14 b of the MOSFET 14 by a connection structure substantially the same as the connection structure between the heat pipe 20 and the MOSFET 14. That is, a plurality of recesses are formed on the lower surface of the heat pipe 24. Each recess has a hexagonal pyramid space shape. Each recess is formed by a bent portion in which the outer wall 24a is bent toward the inner space 24b. The outer wall 24a is thin at the bent portion. Each recess is formed in a range overlapping with the MOSFET 14. The heat pipe 24 is connected to the upper electrode 14b of the MOSFET 14 by a silver layer 42 in a region where each recess is formed. The heat pipe 24 is connected to the lower electrode 12 c of the diode 12 by a connection structure that is substantially the same as the connection structure between the heat pipe 20 and the MOSFET 14. That is, a plurality of recesses are formed on the upper surface of the heat pipe 24. Each recess has a hexagonal pyramid space shape. Each recess is formed by a bent portion in which the outer wall 24a is bent toward the inner space 24b. The outer wall 24a is thin at the bent portion. Each recess is formed in a range overlapping with the diode 12. The heat pipe 24 is connected to the lower electrode 12c of the diode 12 by a silver layer 44 in the region where each recess is formed.
　ヒートパイプ２８は、ダイオード１２の上側に配置されている。ヒートパイプ２８は、外壁２８ａと、密閉された内部空間２８ｂを有している。内部空間２８ｂ内には、少量の液体が封入されている。ヒートパイプ２８は、ヒートパイプ２０とＭＯＳＦＥＴ１４の間の接続構造と略同じ接続構造によって、ダイオード１２の上部電極１２ｂに接続されている。すなわち、ヒートパイプ２８の下面には、複数の凹部が形成されている。各凹部は、六角錐状の空間形状を有している。各凹部は、外壁２８ａが内部空間２８ｂ側に撓んでいる撓み部によって形成されている。撓み部では、外壁２８ａが薄くなっている。各凹部は、ダイオード１２と重なる範囲内に形成されている。ヒートパイプ２８は、各凹部が形成されている領域において、銀層４６によってダイオード１２の上部電極１２ｂに接続されている。 The heat pipe 28 is disposed on the upper side of the diode 12. The heat pipe 28 has an outer wall 28a and a sealed inner space 28b. A small amount of liquid is sealed in the internal space 28b. The heat pipe 28 is connected to the upper electrode 12 b of the diode 12 by a connection structure substantially the same as the connection structure between the heat pipe 20 and the MOSFET 14. That is, a plurality of recesses are formed on the lower surface of the heat pipe 28. Each recess has a hexagonal pyramid space shape. Each recess is formed by a bent portion in which the outer wall 28a is bent toward the inner space 28b. At the bent portion, the outer wall 28a is thin. Each recess is formed in a range overlapping with the diode 12. The heat pipe 28 is connected to the upper electrode 12b of the diode 12 by a silver layer 46 in a region where each recess is formed.
　次に、放熱ユニット１０によって、ダイオード１２とＭＯＳＦＥＴ１４を放熱させる動作について説明する。ＭＯＳＦＥＴ１４に電流が流れると、ＭＯＳＦＥＴ１４が発熱する。ＭＯＳＦＥＴ１４で発生した熱は、銀層４０とヒートパイプ２０の外壁２０ａを介して、ヒートパイプ２０の内部空間２０ｂ内の液体に伝わる。すると、銀層４０が形成されている領域４０ａ（図３参照）内の外壁２０ａと接しているヒートパイプ２０内の液体が気化して、領域４０ａ内の外壁２０ａが冷却される。気化した気体は、ＭＯＳＦＥＴ１４から離れた位置まで流れ、そこで冷やされて液化する。その液体は、ウィックの毛細管現象等によって、銀層４０が形成されている領域４０ａ内の外壁２０ａに接する位置まで戻され、戻された液体がそこで再度気化する。したがって、銀層４０が形成されている領域４０ａ内の外壁２０ａが気化熱によって継続的に冷却され、ＭＯＳＦＥＴ１４が冷却される。放熱ユニット１０では、銀層４０が形成されている領域４０ａ内の外壁２０ａのうちの撓み部２０ｅが、領域４０ａの外側の外壁２０ａよりも薄い。したがって、ＭＯＳＦＥＴ１４で発生した熱が、ヒートパイプ２０の内部の液体に伝わり易い。したがって、ＭＯＳＦＥＴ１４が効率的に冷却される。また、ＭＯＳＦＥＴ１４で発生した熱は、銀層４２とヒートパイプ２４の外壁２４ａを介して、ヒートパイプ２４の内部の液体にも伝わる。したがって、ＭＯＳＦＥＴ１４は、ヒートパイプ２４によっても冷却される。このように、ＭＯＳＦＥＴ１４は、２つのヒートパイプ２０、２４によって冷却される。 Next, the operation of dissipating heat from the diode 12 and the MOSFET 14 by the heat radiating unit 10 will be described. When a current flows through the MOSFET 14, the MOSFET 14 generates heat. The heat generated in the MOSFET 14 is transmitted to the liquid in the internal space 20b of the heat pipe 20 through the silver layer 40 and the outer wall 20a of the heat pipe 20. Then, the liquid in the heat pipe 20 in contact with the outer wall 20a in the region 40a (see FIG. 3) where the silver layer 40 is formed is vaporized, and the outer wall 20a in the region 40a is cooled. The vaporized gas flows to a position away from the MOSFET 14, where it is cooled and liquefied. The liquid is returned to a position in contact with the outer wall 20a in the region 40a where the silver layer 40 is formed by wick capillary phenomenon or the like, and the returned liquid is vaporized again there. Therefore, the outer wall 20a in the region 40a where the silver layer 40 is formed is continuously cooled by the heat of vaporization, and the MOSFET 14 is cooled. In the heat radiating unit 10, the bending part 20e of the outer wall 20a in the area | region 40a in which the silver layer 40 is formed is thinner than the outer wall 20a outside the area | region 40a. Therefore, the heat generated in the MOSFET 14 is easily transferred to the liquid inside the heat pipe 20. Therefore, the MOSFET 14 is efficiently cooled. The heat generated in the MOSFET 14 is also transmitted to the liquid inside the heat pipe 24 via the silver layer 42 and the outer wall 24 a of the heat pipe 24. Therefore, the MOSFET 14 is also cooled by the heat pipe 24. Thus, the MOSFET 14 is cooled by the two heat pipes 20 and 24.
　また、ダイオード１２に電流が流れると、ダイオード１２が発熱する。ダイオード１２で発生した熱は、銀層４６とヒートパイプ２８の外壁２８ａを介して、ヒートパイプ２８の内部の液体に伝わる。したがって、ダイオード１２は、ヒートパイプ２８によって冷却される。撓み部が薄いので、ダイオード１２で発生した熱は、ヒートパイプ２８の内部の液体に伝わり易い。したがって、ダイオード１２が効率的に冷却される。また、ダイオード１２で発生した熱は、銀層４４とヒートパイプ２４の外壁２４ａを介して、ヒートパイプ２４の内部の液体にも伝わる。したがって、ダイオード１２は、ヒートパイプ２４によっても冷却される。このように、ダイオード１２は、２つのヒートパイプ２４、２８によって冷却される。 Further, when a current flows through the diode 12, the diode 12 generates heat. The heat generated in the diode 12 is transmitted to the liquid inside the heat pipe 28 via the silver layer 46 and the outer wall 28 a of the heat pipe 28. Therefore, the diode 12 is cooled by the heat pipe 28. Since the bent portion is thin, the heat generated by the diode 12 is easily transferred to the liquid inside the heat pipe 28. Therefore, the diode 12 is efficiently cooled. The heat generated in the diode 12 is also transmitted to the liquid inside the heat pipe 24 via the silver layer 44 and the outer wall 24 a of the heat pipe 24. Therefore, the diode 12 is also cooled by the heat pipe 24. Thus, the diode 12 is cooled by the two heat pipes 24 and 28.
　次に、放熱ユニット１０の製造方法について説明する。最初に、図４に示すように、銀ナノ粒子層５０、５２、５４、５６を介在させた状態で、ヒートパイプ２０、ＭＯＳＦＥＴ１４、ヒートパイプ２４、ダイオード１２、及び、ヒートパイプ２８を積層する。銀ナノ粒子層５０、５２、５４、５６は、有機、又は、無機のバインダに銀ナノ粒子を分散させたペーストを塗布することで形成した層であり、粘性を有する。このとき用いる銀ナノ粒子の平均粒径は、１００ｎｍ以下であることが好ましい。ここでは、銀ナノ粒子層５０、５２、５４、５６を、各ヒートパイプの各凹部内と凹部の周囲に形成する。また、ＭＯＳＦＥＴ１４と重なる範囲内にヒートパイプ２０の凹部２２とヒートパイプ２４の下面の凹部が配置され、ダイオード１２と重なる範囲内にヒートパイプ２４の上面の凹部とヒートパイプ２８の凹部が配置されるように、ヒートパイプ２０、ＭＯＳＦＥＴ１４、ヒートパイプ２４、ダイオード１２、及び、ヒートパイプ２８を積層する。 Next, a method for manufacturing the heat dissipation unit 10 will be described. First, as shown in FIG. 4, the heat pipe 20, the MOSFET 14, the heat pipe 24, the diode 12, and the heat pipe 28 are stacked with the silver nanoparticle layers 50, 52, 54, and 56 interposed. The silver nanoparticle layers 50, 52, 54, and 56 are layers formed by applying a paste in which silver nanoparticles are dispersed in an organic or inorganic binder, and have viscosity. The average particle diameter of the silver nanoparticles used at this time is preferably 100 nm or less. Here, the silver nanoparticle layers 50, 52, 54, and 56 are formed in and around the recesses of the heat pipes. Further, the concave portion 22 of the heat pipe 20 and the concave portion of the lower surface of the heat pipe 24 are disposed within the range overlapping with the MOSFET 14, and the concave portion of the upper surface of the heat pipe 24 and the concave portion of the heat pipe 28 are disposed within the range overlapping with the diode 12. As described above, the heat pipe 20, the MOSFET 14, the heat pipe 24, the diode 12, and the heat pipe 28 are stacked.
　ヒートパイプ２０、ＭＯＳＦＥＴ１４、ヒートパイプ２４、ダイオード１２、及び、ヒートパイプ２８の積層体６０を形成したら、積層体６０を支持板６２、６４によって積層方向に挟み込む。そして、ネジ６６、６８によって支持板６２、６４を接続する。このようにして、ヒートパイプ２０、ＭＯＳＦＥＴ１４、ヒートパイプ２４、ダイオード１２、及び、ヒートパイプ２８が、互いに離反する方向に相対移動することを規制する。この状態で、積層体６０を加熱炉によって２００℃～３００℃に加熱する。すると、ヒートパイプ２０、２４、２８の内部の液体が気化して、ヒートパイプ２０、２４、２８がわずかに膨張する。積層体６０の上下は支持板６２、６４によって挟まれているので、ヒートパイプ２０、２４、２８の膨張によって、銀ナノ粒子層５０、５２、５４、５６が加圧される。すなわち、銀ナノ粒子層５０、５２、５４、５６が、加圧された状態で加熱される。すると、銀ナノ粒子層５０、５２、５４、５６中の銀ナノ粒子が互いに接合して、銀ナノ粒子層５０、５２、５４、５６が焼結される。これによって、銀ナノ粒子層５０、５２、５４、５６が、バルク状の銀層４０、４２、４４、４６（図１参照）となる。また、各銀層とヒートパイプの外壁との境界には、銀とヒートパイプの外壁の構成金属（本実施例では銅）との合金層が形成される。この合金層によって、銀層とヒートパイプの外壁とが接合される。また、各銀層と半導体装置の電極との境界には、銀と半導体装置の電極の構成金属との合金層が形成される。この合金層によって、銀層と半導体装置の電極とが接合される。したがって、バルク化した銀層４０は、ヒートパイプ２０の上面と接合されるとともに、ＭＯＳＦＥＴ１４の下部電極１４ｃと接合される。すなわち、ヒートパイプ２０の上面とＭＯＳＦＥＴ１４の下部電極１４ｃが銀層４０によって接続される。同様にして、ＭＯＳＦＥＴ１４の上部電極１４ｂとヒートパイプ２４の下面が銀層４２によって接続され、ヒートパイプ２４の上面とダイオード１２の下部電極１２ｃが銀層４４によって接続され、ダイオード１２の上部電極１２ｂとヒートパイプ２８の下面が銀層４６によって接続される。これによって、図１の放熱ユニット１０が製造される。 When the laminated body 60 of the heat pipe 20, the MOSFET 14, the heat pipe 24, the diode 12, and the heat pipe 28 is formed, the laminated body 60 is sandwiched between the support plates 62 and 64 in the lamination direction. Then, the support plates 62 and 64 are connected by screws 66 and 68. In this manner, the relative movement of the heat pipe 20, the MOSFET 14, the heat pipe 24, the diode 12, and the heat pipe 28 in a direction away from each other is restricted. In this state, the laminate 60 is heated to 200 ° C. to 300 ° C. by a heating furnace. Then, the liquid inside the heat pipes 20, 24, 28 is vaporized, and the heat pipes 20, 24, 28 are slightly expanded. Since the upper and lower sides of the laminate 60 are sandwiched between the support plates 62 and 64, the silver nanoparticle layers 50, 52, 54, and 56 are pressurized by the expansion of the heat pipes 20, 24, and 28. That is, the silver nanoparticle layers 50, 52, 54, and 56 are heated in a pressurized state. Then, the silver nanoparticles in the silver nanoparticle layers 50, 52, 54, and 56 are joined together, and the silver nanoparticle layers 50, 52, 54, and 56 are sintered. As a result, the silver nanoparticle layers 50, 52, 54, and 56 become bulky silver layers 40, 42, 44, and 46 (see FIG. 1). Further, an alloy layer of silver and a constituent metal (copper in this embodiment) of the outer wall of the heat pipe is formed at the boundary between each silver layer and the outer wall of the heat pipe. By this alloy layer, the silver layer and the outer wall of the heat pipe are joined. In addition, an alloy layer of silver and a constituent metal of the electrode of the semiconductor device is formed at the boundary between each silver layer and the electrode of the semiconductor device. The alloy layer joins the silver layer and the electrode of the semiconductor device. Therefore, the bulked silver layer 40 is bonded to the upper surface of the heat pipe 20 and to the lower electrode 14 c of the MOSFET 14. That is, the upper surface of the heat pipe 20 and the lower electrode 14 c of the MOSFET 14 are connected by the silver layer 40. Similarly, the upper electrode 14b of the MOSFET 14 and the lower surface of the heat pipe 24 are connected by the silver layer 42, the upper surface of the heat pipe 24 and the lower electrode 12c of the diode 12 are connected by the silver layer 44, and the upper electrode 12b of the diode 12 The lower surface of the heat pipe 28 is connected by a silver layer 46. Thereby, the heat radiating unit 10 of FIG. 1 is manufactured.
　このように、この製造方法では、ヒートパイプ２０、２４、２８が膨張することで銀ナノ粒子層５０、５２、５４、５６に高い圧力が印加される。すなわち、ヒートパイプ２０、ＭＯＳＦＥＴ１４、ヒートパイプ２４、ダイオード１２、及び、ヒートパイプ２８が、互いに離反する方向に相対移動することを規制した状態で、積層体６０を加熱するだけで、銀ナノ粒子層５０、５２、５４、５６を加圧することができる。したがって、支持板６２、６４によって積層体６０を挟み込む力（すなわち、外部から積層体６０を加圧する力）はほとんど必要ない。このため、上述した支持板６２、６４及びネジ６６、６８のような簡単な治具で放熱ユニット１０を製造することができる。すなわち、この製造方法によれば、放熱ユニット１０を効率的に製造することができる。 Thus, in this manufacturing method, a high pressure is applied to the silver nanoparticle layers 50, 52, 54, and 56 due to the expansion of the heat pipes 20, 24, and 28. That is, the silver nanoparticle layer can be obtained simply by heating the stacked body 60 in a state where the heat pipe 20, the MOSFET 14, the heat pipe 24, the diode 12, and the heat pipe 28 are restricted from moving relative to each other. 50, 52, 54, 56 can be pressurized. Therefore, a force for sandwiching the laminate 60 between the support plates 62 and 64 (that is, a force for pressing the laminate 60 from the outside) is hardly required. For this reason, the heat radiation unit 10 can be manufactured with a simple jig such as the support plates 62 and 64 and the screws 66 and 68 described above. That is, according to this manufacturing method, the heat radiating unit 10 can be manufactured efficiently.
　また、ヒートパイプ２０の外壁２０ａのうちの内部空間２０ｂ側に撓んでいる撓み部２０ｅは、内部空間２０ｂの気圧が上昇したときに外側に向かって変形しやすい。また、撓み部２０ｅは薄く、これによっても、撓み部２０ｅは外側に向かって変形し易くなっている。上述した積層体６０の加熱によって内部空間２０ｂ内の気圧が上昇するときには、撓み部２０ｅが銀ナノ粒子層５０（特に、凹部２２内の銀ナノ粒子層５０）とＭＯＳＦＥＴ１４によって外側から支持されることによって、撓み部２０ｅの外側への変形が抑制される。このため、ＭＯＳＦＥＴ１４と撓み部２０ｅに挟まれている銀ナノ粒子層５０には、特に高い圧力が加わる。これにより、銀ナノ粒子層５０をより高い圧力下で焼成することができるので、ヒートパイプ２０とＭＯＳＦＥＴ１４をより強固に接続することができる。このように、銀ナノ粒子を塗布する領域（図３の領域４０ａに相当する領域）内の外壁２０ａに変形しやすい領域を設けておくことで、ヒートパイプ２０とＭＯＳＦＥＴ１４をより強く接続することができる。また、銀ナノ粒子を塗布する領域内の外壁２０ａに変形しやすい領域を設けても、加熱時にこの領域は銀ナノ粒子層５０及びＭＯＳＦＥＴ１４によって支持されるので、この変形しやすい領域が破損することはない。また、銀ナノ粒子を塗布しない領域の外壁２０ａは、厚いので、加熱時の内部空間２０ｂ内の気圧に耐えることができる。このため、この製造方法によれば、加熱時にヒートパイプ２０が破裂することを防止することができる。ヒートパイプ２４とヒートパイプ２８でも同様のことが言える。したがって、この製造方法によれば、高い製造歩留まりで放熱ユニット１０を製造することができる。 Also, the bent portion 20e of the outer wall 20a of the heat pipe 20 that is bent toward the inner space 20b easily deforms outward when the atmospheric pressure in the inner space 20b rises. Moreover, the bending part 20e is thin and the bending part 20e also becomes easy to deform | transform toward an outer side by this. When the atmospheric pressure in the internal space 20b rises due to the heating of the laminated body 60 described above, the bent portion 20e is supported from the outside by the silver nanoparticle layer 50 (in particular, the silver nanoparticle layer 50 in the recess 22) and the MOSFET 14. Thus, the outward deformation of the bent portion 20e is suppressed. For this reason, a particularly high pressure is applied to the silver nanoparticle layer 50 sandwiched between the MOSFET 14 and the flexure 20e. Thereby, since the silver nanoparticle layer 50 can be baked under a higher pressure, the heat pipe 20 and the MOSFET 14 can be more firmly connected. As described above, by providing a region that is easily deformed on the outer wall 20a in the region to which the silver nanoparticles are applied (the region corresponding to the region 40a in FIG. 3), the heat pipe 20 and the MOSFET 14 can be more strongly connected. it can. Further, even if a region easily deformed is provided on the outer wall 20a in the region where the silver nanoparticles are applied, this region easily supported by the silver nanoparticle layer 50 and the MOSFET 14 during heating may be damaged. There is no. Moreover, since the outer wall 20a of the area | region which does not apply | coat a silver nanoparticle is thick, it can endure the atmospheric pressure in the internal space 20b at the time of a heating. For this reason, according to this manufacturing method, it can prevent that the heat pipe 20 bursts at the time of a heating. The same can be said for the heat pipe 24 and the heat pipe 28. Therefore, according to this manufacturing method, the heat radiating unit 10 can be manufactured with a high manufacturing yield.
　以上に説明したように、実施例の製造方法によれば、３００℃以上の融点を有する金属層によって被放熱部材（ダイオード１２、又は、ＭＯＳＦＥＴ１４）が、ヒートパイプ（２０、２４、２８）に接続された放熱ユニットを効率的に製造することができる。 As described above, according to the manufacturing method of the embodiment, the heat radiating member (diode 12 or MOSFET 14) is connected to the heat pipe (20, 24, 28) by the metal layer having a melting point of 300 ° C. or higher. It is possible to efficiently manufacture the heat dissipation unit.
　なお、図５に示すように、複数の積層体６０を支持板６２、６４で挟んで加熱するようにしてもよい。各ヒートパイプの膨張によって銀ナノ粒子層が加圧されるので、このように複数の積層体６０を一対の支持板６２、６４で挟んで加熱しても、各積層体６０を十分に加圧することができる。また、このような構成によれば、より効率よく放熱ユニット１０を製造することができる。 In addition, as shown in FIG. 5, a plurality of laminated bodies 60 may be sandwiched between support plates 62 and 64 and heated. Since the silver nanoparticle layer is pressurized by the expansion of each heat pipe, even when the plurality of laminated bodies 60 are sandwiched between the pair of support plates 62 and 64 and heated as described above, each laminated body 60 is sufficiently pressurized. be able to. Moreover, according to such a structure, the thermal radiation unit 10 can be manufactured more efficiently.
　次に、上述した実施例を変形した変形例について説明する。なお、変形例については、ヒートパイプ２０とＭＯＳＦＥＴ１４との接続部についてのみ説明する。 Next, a modified example in which the above-described embodiment is modified will be described. In addition, about a modification, only the connection part of the heat pipe 20 and MOSFET14 is demonstrated.
　上述した実施例では、外壁２０ａの撓み部２０ｅが、内部空間２０ｂ側に向かって撓んでいるとともに、撓み部２０ｅ以外の外壁２０ａよりも薄かった。しかしながら、図６に示すように、銀層４０が形成されている領域４０ａ内に、撓んでおらず、領域４０ａの外側の外壁２０ａよりも薄い薄肉部２０ｆが形成されていてもよい。このような薄肉部２０ｆは、撓んでいなくても、変形し易い。したがって、薄肉部２０ｆを設けることで、製造工程における加熱時に、薄肉部２０ｆに接する銀ナノ粒子層を効果的に加圧することができ、ヒートパイプ２０とＭＯＳＦＥＴ１４を強固に接続することができる。また、図６では、外壁２０ａの外面（上面２０ｄ）に凹部が形成されることで薄肉部が形成されているが、図７に示すように、外壁２０ａの内面に凹部が形成されることで薄肉部２０ｆが形成されていてもよい。図７の構成でも、ヒートパイプ２０とＭＯＳＦＥＴ１４を強固に接続することができる。また、図８に示すように、薄肉部２０ｆが、ＭＯＳＦＥＴ１４よりも広い範囲に形成されていてもよい。このような構成でも、薄肉部２０ｆとＭＯＳＦＥＴ１４の間の銀層４０を効率的に加圧することができる。また、薄肉部２０ｆ上に銀層４０が形成されていれば、製造工程における加熱時にＭＯＳＦＥＴ１４と銀層４０によって薄肉部２０ｆを支持できるので、薄肉部２０ｆの破損を防止できる。 In the embodiment described above, the bent portion 20e of the outer wall 20a is bent toward the inner space 20b side and is thinner than the outer wall 20a other than the bent portion 20e. However, as shown in FIG. 6, a thin portion 20f that is not bent and is thinner than the outer wall 20a outside the region 40a may be formed in the region 40a where the silver layer 40 is formed. Such a thin portion 20f is easily deformed even if it is not bent. Therefore, by providing the thin portion 20f, the silver nanoparticle layer in contact with the thin portion 20f can be effectively pressurized during heating in the manufacturing process, and the heat pipe 20 and the MOSFET 14 can be firmly connected. Further, in FIG. 6, a thin portion is formed by forming a recess on the outer surface (upper surface 20d) of the outer wall 20a. However, as shown in FIG. 7, a recess is formed on the inner surface of the outer wall 20a. The thin part 20f may be formed. Even in the configuration of FIG. 7, the heat pipe 20 and the MOSFET 14 can be firmly connected. Further, as shown in FIG. 8, the thin portion 20 f may be formed in a wider range than the MOSFET 14. Even with such a configuration, it is possible to efficiently pressurize the silver layer 40 between the thin portion 20 f and the MOSFET 14. Further, if the silver layer 40 is formed on the thin portion 20f, the thin portion 20f can be supported by the MOSFET 14 and the silver layer 40 during heating in the manufacturing process, so that the thin portion 20f can be prevented from being damaged.
　また、上述した実施例では、撓み部２０ｅが薄く形成されていたが、図９に示すように、撓み部２０ｅが薄くなくてもよい。図９では、撓み部２０ｅの厚さが、撓み部２０ｅ以外の外壁２０ａの厚さと等しい。外壁２０ａは、薄くなくても、撓んでいれば、変形しやすい。したがって、薄くない撓み部２０ｅを設けても、製造工程における加熱時に、撓み部２０ｅに接する銀ナノ粒子層４０を効果的に加圧することができ、ヒートパイプ２０とＭＯＳＦＥＴ１４を強固に接続することができる。また、上述した実施例では、撓み部２０ｅが密集して形成されていたが、撓み部２０ｅが離散的に形成されていてもよい。 In the above-described embodiment, the bent portion 20e is formed thin. However, as shown in FIG. 9, the bent portion 20e may not be thin. In FIG. 9, the thickness of the bent portion 20e is equal to the thickness of the outer wall 20a other than the bent portion 20e. Even if the outer wall 20a is not thin, it is easily deformed if it is bent. Therefore, even if the thin bending part 20e is provided, the silver nanoparticle layer 40 in contact with the bending part 20e can be effectively pressurized during heating in the manufacturing process, and the heat pipe 20 and the MOSFET 14 can be firmly connected. it can. Moreover, in the Example mentioned above, although the bending part 20e was formed densely, the bending part 20e may be formed discretely.
　また、上述した実施例では、金属ナノ粒子として銀ナノ粒子を用いたが、他の金属のナノ粒子を用いてもよい。また、上述した実施例では、ダイオード及びＭＯＳＦＥＴをヒートパイプに接続した放熱ユニットについて説明した。しかしながら、他の半導体装置や、熱伝導部材（例えば、銅板等）の他の被放熱部材がヒートパイプに接続されていてもよい。 In the above-described embodiments, silver nanoparticles are used as the metal nanoparticles, but other metal nanoparticles may be used. Moreover, the Example mentioned above demonstrated the thermal radiation unit which connected the diode and MOSFET to the heat pipe. However, other semiconductor devices and other heat radiating members such as heat conducting members (for example, copper plates) may be connected to the heat pipe.
　また、ヒートパイプの外壁は、薄肉部以外の領域において、０．１ｍｍ以上かつ３．０ｍｍ以下の厚さを有していることが好ましい。これは、ヒートパイプの外壁の厚さが０．１ｍｍ未満であれば、放熱ユニットの製造工程における加熱時にヒートパイプが破損（破裂）するおそれがあるためである。また、ヒートパイプの外壁の厚さが３．０ｍｍより大きければ、ヒートパイプの内部と外部との間での熱伝導が生じ難くなり、ヒートパイプの内部の液体による冷却効果を十分に生じさせることができないためである。 Moreover, it is preferable that the outer wall of the heat pipe has a thickness of 0.1 mm or more and 3.0 mm or less in a region other than the thin portion. This is because if the thickness of the outer wall of the heat pipe is less than 0.1 mm, the heat pipe may be damaged (exploded) during heating in the manufacturing process of the heat dissipation unit. In addition, if the thickness of the outer wall of the heat pipe is larger than 3.0 mm, heat conduction between the inside and outside of the heat pipe is difficult to occur, and the cooling effect by the liquid inside the heat pipe is sufficiently generated. This is because they cannot.
　また、ヒートパイプの外壁は、銅、アルミニウム、ニッケル、鋼、ステンレス鋼等のように、熱伝導率が高く、かつ、金属ナノ粒子と接合し易い材質により構成されていることが好ましい。また、半導体装置の電極は、金、銅、ニッケル、アルミニウム、タングステン、ＡｌＳｉ等のように、熱伝導率が高く、かつ、金属ナノ粒子と接合し易い材質により構成されていることが好ましい。 Also, the outer wall of the heat pipe is preferably made of a material that has high thermal conductivity and can be easily bonded to metal nanoparticles, such as copper, aluminum, nickel, steel, and stainless steel. Moreover, it is preferable that the electrode of the semiconductor device is made of a material having high thermal conductivity and being easily bonded to metal nanoparticles, such as gold, copper, nickel, aluminum, tungsten, and AlSi.
　以上、実施例について詳細に説明したが、これらは例示にすぎず、特許請求の範囲を限定するものではない。特許請求の範囲に記載の技術には、以上に例示した具体例をさまざまに変形、変更したものが含まれる。
　本明細書または図面に説明した技術要素は、単独であるいは各種の組み合わせによって技術的有用性を発揮するものであり、出願時請求項記載の組み合わせに限定されるものではない。また、本明細書または図面に例示した技術は複数目的を同時に達成するものであり、そのうちの一つの目的を達成すること自体で技術的有用性を持つものである。 As mentioned above, although the Example was described in detail, these are only illustrations and do not limit a claim. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.
The technical elements described in the present specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology illustrated in the present specification or the drawings achieves a plurality of objects at the same time, and has technical utility by achieving one of the objects.
１０：放熱ユニット
１２：ダイオード
１４：ＭＯＳＦＥＴ
２０：ヒートパイプ
２０ａ：外壁
２０ｂ：内部空間
２０ｅ：撓み部
２２：凹部
２４：ヒートパイプ
２８：ヒートパイプ
４０：銀層
４２：銀層
４４：銀層
４６：銀層 10: Heat dissipation unit 12: Diode 14: MOSFET
20: Heat pipe 20a: Outer wall 20b: Internal space 20e: Deflection 22: Recess 24: Heat pipe 28: Heat pipe 40: Silver layer 42: Silver layer 44: Silver layer 46: Silver layer

Claims (8)

  1. 　ヒートパイプと、
    　被放熱部材と、
    　ヒートパイプと被放熱部材とを接続している金属層、
    　を有しており、
    　金属層が、３００℃以上の融点を有することを特徴とする放熱ユニット。     Heat pipes,
    A heat radiating member;
    A metal layer connecting the heat pipe and the heat radiating member,
    Have
    A heat dissipation unit, wherein the metal layer has a melting point of 300 ° C. or higher.
  2. 　金属層が形成されている金属層形成領域内のヒートパイプの外壁の少なくとも一部に、金属層形成領域外のヒートパイプの外壁よりも薄い薄肉部が形成されていることを特徴とする請求項１に記載の放熱ユニット。 The thin wall portion thinner than the outer wall of the heat pipe outside the metal layer forming region is formed on at least a part of the outer wall of the heat pipe in the metal layer forming region where the metal layer is formed. The heat dissipation unit according to 1.
  3. 　ヒートパイプと被放熱部材の積層方向に沿ってヒートパイプを見たときにヒートパイプと被放熱部材とが重なる範囲内に薄肉部全体が含まれていることを特徴とする請求項２に記載の放熱ユニット。 The whole thin portion is included in a range where the heat pipe and the heat radiating member overlap when the heat pipe is viewed along the stacking direction of the heat pipe and the heat radiating member. Heat dissipation unit.
  4. 　金属層が形成されている金属層形成領域内であって、ヒートパイプと被放熱部材の積層方向に沿ってヒートパイプを見たときにヒートパイプと被放熱部材とが重なる範囲内のヒートパイプの外壁に、ヒートパイプの内側に向かって撓んでいる撓み部が形成されていることを特徴とする請求項１～３の何れか一項に記載の放熱ユニット。 In the metal layer forming region where the metal layer is formed, the heat pipe within a range where the heat pipe and the heat radiating member overlap when the heat pipe is viewed along the stacking direction of the heat pipe and the heat radiating member. The heat radiating unit according to any one of claims 1 to 3, wherein a bent portion that is bent toward the inside of the heat pipe is formed on the outer wall.
  5. 　ヒートパイプと被放熱部材との間に金属ナノ粒子層を介在させた状態で、金属ナノ粒子層を加熱することで、金属ナノ粒子層を焼結させることを特徴とする放熱ユニットの製造方法。 A method of manufacturing a heat dissipation unit, comprising heating a metal nanoparticle layer with the metal nanoparticle layer interposed between a heat pipe and a heat radiating member, thereby sintering the metal nanoparticle layer.
  6. 　ヒートパイプの外壁の一部に、その周囲よりも薄い薄肉部が形成されており、
    　薄肉部の表面に金属ナノ粒子層が接触するようにして、前記加熱を行うことを特徴とする請求項５に記載の製造方法。     A thin part thinner than the periphery is formed on a part of the outer wall of the heat pipe,
    The manufacturing method according to claim 5, wherein the heating is performed such that the metal nanoparticle layer is in contact with the surface of the thin portion.
  7. 　ヒートパイプと被放熱部材の積層方向に沿ってヒートパイプを見たときにヒートパイプと被放熱部材とが重なる範囲内に薄肉部全体が含まれるようにして、前記加熱を行うことを特徴とする請求項６に記載の製造方法。 When the heat pipe is viewed along the stacking direction of the heat pipe and the heat radiating member, the heating is performed so that the entire thin portion is included in a range where the heat pipe and the heat radiating member overlap. The manufacturing method according to claim 6.
  8. 　ヒートパイプの外壁の一部に、ヒートパイプの内側に向かって撓んでいる撓み部が形成されており、
    　撓み部の表面に金属ナノ粒子層が接触し、かつ、ヒートパイプと被放熱部材の積層方向に沿ってヒートパイプを見たときにヒートパイプと被放熱部材とが重なる範囲内に撓み部全体が含まれるようにして、前記加熱を行うことを特徴とする請求項５～７の何れか一項に記載の製造方法。     A bent part that is bent toward the inside of the heat pipe is formed on a part of the outer wall of the heat pipe,
    When the metal nanoparticle layer is in contact with the surface of the bending portion and the heat pipe is viewed along the stacking direction of the heat pipe and the heat radiating member, the entire bending portion is within a range where the heat pipe and the heat radiating member overlap. The production method according to any one of claims 5 to 7, wherein the heating is performed so as to be included.
PCT/JP2011/067704 2011-08-02 2011-08-02 Heat radiation unit and method for manufacturing same WO2013018200A1 (en)

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Application Number Priority Date Filing Date Title
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Publications (1)

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006308239A (en) * 2005-04-28 2006-11-09 Hitachi Cable Ltd Heat pipe type heat sink and its manufacturing method
JP2009216343A (en) * 2008-03-12 2009-09-24 Furukawa Electric Co Ltd:The Heat transfer hinge device and cooling apparatus
JP2009287821A (en) * 2008-05-28 2009-12-10 Denso Corp Heat exchanging device

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006308239A (en) * 2005-04-28 2006-11-09 Hitachi Cable Ltd Heat pipe type heat sink and its manufacturing method
JP2009216343A (en) * 2008-03-12 2009-09-24 Furukawa Electric Co Ltd:The Heat transfer hinge device and cooling apparatus
JP2009287821A (en) * 2008-05-28 2009-12-10 Denso Corp Heat exchanging device

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