Heat sink and method for manufacturing same

Abstract

A heat sink capable of permitting heat transfer from an electronic component to the heat sink to be effectively promoted while reducing a manufacturing cost of the heat sink and increasing yields thereof. The heat sink includes a base plate adaptable to be kept in direct contact with an electronic component which requires that heat be dissipated therefrom during operation thereof and radiation fins arranged so as to project from the base plate. The base plate includes a main base plate section made of a main material of which the radiation fins are made and a heat transfer promoting base plate section made of a heat transfer promoting material different from the material of which the main base plate section is made. The heat transfer promoting material is integrated with said main material at a stage at which working of a workpiece. This permits heat generated from the electronic component to be dispersed over the whole heat transfer base plate section and then transferred through the whole main base plate section to the radiation fins, so that the heat sink may be increased in heat dissipation efficiency.

1 . A heat sink for dissipating heat from an electronic component, comprising:
 a base plate formed of a heat transfer promoting material, said base plate being adaptable to be kept in direct contact with said electronic component; and   radiation fins formed of a main material and projecting from said base plate;   
     
     
         2 . A heat sink as defined in  claim 1 , wherein said main material is aluminum alloy and said heat transfer promoting material has a thermal conductivity larger than the thermal conductivity of aluminum. 
     
     
         3 . A heat sink as defined in  claim 2 , wherein said heat transfer promoting material is selected from the group consisting of copper and copper alloy. 
     
     
         4 . A heat sink as defined in  claim 2 , wherein said main material and heat transfer promoting material are coupled together by a technique selected from the group consisting of brazing, pressure welding by forging, deformation with intermeshing and any combination thereof. 
     
     
         5 . A heat sink as defined in  claim 2 , wherein said heat transfer promoting material is coupled to said main material by plating said heat transfer promoting material on said main material. 
     
     
         6 . A heat sink as defined in  claim 2 , wherein said main material and said heat transfer promoting material define a joint portion where said main material and said heat transfer material are coupled together increase a contact area therebetween. 
     
     
         7 . A heat sink as defined in  claim 1 , wherein said heat transfer promoting material is selected from the group consisting of copper and copper alloy. 
     
     
         8 . A heat sink as defined in  claim 1 , wherein said main material and heat transfer promoting material are coupled together by a technique selected from the group consisting of brazing, pressure welding by forging, deformation with intermeshing, and any combination thereof. 
     
     
         9 . A heat sink as defined in  claim 1 , wherein said heat transfer promoting material is coupled to said main material by plating said heat transfer promoting material on said main material. 
     
     
         10 . A heat sink as defined in  claim 1 , wherein said main material and said heat transfer promoting material define a joint portion where said main material and said heat transfer material are coupled together increase a contact area therebetween. 
     
     
         11 . A heat sink for dissipating heat from an electronic component comprising a base plate and radiation fins projecting from said base plate, said base plate in detachable contact with said electronic component, said base plate comprising a composite material including a main material comprising a main base plate portion located adjacent to said radiation fin and a heat transfer promoting material which have been coupled to each other, said base plate including at least a portion located on the side thereof opposite from said radiation fins comprising said heat transfer promoting material comprising a heat transfer promoting base plate portion located on a side thereof opposite from said radiation fins and being in direct contact with said electronic component, said radiation fins and said main material being integrally formed as a seamless one-piece structure, and said main material and said heat transfer promoting material define a joint portion where said main material and heat transfer material are coupled together so as to increase a contact area therebetween;
 said main material comprising an aluminum alloy and said heat transfer promoting material having a thermal conductivity larger than the thermal conductivity of said aluminum alloy;   said main base plate portion and said heat transfer promoting base plate portion having respective opposing surfaces of the same shape when viewed in plan view and bonded through the entire opposing surfaces thereof.   
     
     
         12 . A heat sink as defined in  claim 11 , wherein said heat transfer promoting material is selected from the group consisting of copper and copper alloy. 
     
     
         13 . A heat sink as defined in  claim 11 , wherein said main material and heat transfer promoting material are coupled together by a technique selected from the group consisting of brazing, pressure welding by forging, deformation with intermeshing, and any combination thereof. 
     
     
         14 . A heat sink as defined in  claim 11 , wherein said heat transfer promoting material is coupled to said main material by plating said heat transfer promoting material on said main material. 
     
     
         15 . A heat sink as defined in  claim 11  wherein said base plate comprises said heat transfer promoting material. 
     
     
         16 . A heat sink for dissipating heat from an electronic component comprising a base plate having a first surface in detachable contact with said electronic component and a second surface opposite from said first surface, and radiation fins projecting from said second surface of said base plate, said base plate and said radiation fins being integral and formed of a composite material including a main material comprising an aluminum alloy and a heat transfer promoting material which have been coupled to each other, said heat transfer promoting material having a thermal conductivity greater than the thermal conductivity of said aluminum alloy, said base plate including a main base plate portion located adjacent to said radiation fins to form said second surface thereof, and a heat transfer promoting base portion located on a surface opposite from said radiation fins to form said first surface thereof and being in direct contact with said electronic component, said main base plate portion and said radiation fins comprising said main material and said heat transfer promoting base plate portion comprising a heat transfer promoting material, and wherein said main material and said heat transfer promoting material define a joint portion where said main material and said heat transfer promoting material are coupled together so as to increase a contact area therebetween;
 said main base plate portion and said heat transfer promoting base plate portion having respective opposing surfaces of the same shape when viewed in a plan view and being bonded through the entire opposing surfaces thereof.   
     
     
         17 . A heat sink as defined in  claim 16  wherein said main material comprises an aluminum alloy, and said heat transfer promoting material comprises a material having thermal conductivity greater than the thermal conductivity of aluminum. 
     
     
         18 . A heat sink as defined in  claim 16  wherein said heat transfer promoting material comprises a material selected from the group consisting of copper and copper alloy. 
     
     
         19 . A heat sink as defined in  claim 16  wherein said main material and said heat transfer promoting material are coupled together by a technique selected from the group consisting of brazing, pressure welding by forging, deformation with intermeshing, and combinations thereof. 
     
     
         20 . A heat sink as defined in  claim 16  wherein said heat transfer promoting material is coupled to said main material by plating said heat transfer promoting material on said main material. 
     
     
         21 . A heat sink for dissipating heat from an electronic component comprising a base plate and radiation fins projecting from said base plate, said base plate being maintained in direct contact with said electronic component, said base plate comprising a composite material including a main material comprising an aluminum alloy and a heat transfer promoting material which have been coupled to each other said heat transfer promoting material having a thermal conductivity larger than the thermal conductivity of aluminum, said base plate including at least a portion located on the side thereof opposite from said radiation fins comprising said heat transfer promoting material in direct contact with said electronic component, said radiation fins and said main material being unitarily formed as a seamless one-piece structure, said radiation fins being formed by plastic deformation of said main material;
 said main material and said heat transfer promoting material having respective opposing surfaces of the same shape when viewed in plan view and being bonded through the entire opposing surfaces thereof.   
     
     
         22 . A heat sink as defined in  claim 21 , wherein said main material is an aluminum alloy and said heat transfer promoting material has a thermal conductivity larger than the thermal conductivity of aluminum. 
     
     
         23 . A heat sink as defined in  claim 21 , wherein said heat transfer promoting material is selected from the group consisting of copper and copper alloy. 
     
     
         24 . A heat sink as defined in  claim 21 , wherein said main material and heat transfer promoting material are coupled together by a technique selected from the group consisting of brazing, pressure welding by forging, deformation with intermeshing, and any combination thereof. 
     
     
         25 . A heat sink for dissipating heat from an electronic component comprising a base plate having a first surface in detachable contact with said electronic component and a second surface opposite from said first surface, and radiation fins projecting from said second surface of said base plate, said base plate and said radiation fins being integral and formed of a composite material including a main material made of aluminum alloy and a heat transfer promoting material which have been coupled to each other, said heat transfer promoting material being in direct contact with said electronic component and having a thermal conductivity greater than the thermal conductivity of said aluminum alloy, said base plate including a main base plate portion including a first joining surface opposite from said opposite from said second surface of said base plate, and located adjacent to said radiation fins to form said second surface thereof, and a heat transfer promoting base portion including a second joining surface in contact with said first joining surface located on a surface opposite from said radiation fins to form said first surface thereof, said main base plate portion and said radiation fins being unitarily formed as a seamless one-piece structure, said radiation fins being formed by plastic deformation of said main material, and said heat transfer promoting base plate portion comprising a heat transfer promoting material;
 said first and second joining surfaces having the same outer configuration whereby said main base plate portion and said heat transfer promotion base portion are coupled together through the entire joining surfaces thereof.