Heat sink adapted for dissipating heat from a semiconductor device

Abstract

A heat sink adapted for dissipating heat from a semiconductor device. The heat sink has lower heat sink body, an upper heat sink body soldered to the lower heat sink body, an airtight chamber defined in between the upper heat sink body and the lower heat sink body and drawn into a vacuum status, a working fluid filled in the airtight chamber for circulation between gas phase and liquid phase to transfer heat energy from the bottom side of the heat sink toward the top side thereof, and a porous structure formed in the upper heat sink body and the lower heat sink body inside the airtight chamber for accelerating the circulation of the working fluid between gas phase and liquid phase.

What the invention claimed is:  
     
         1 . A heat sink comprising a lower heat sink body, said lower heat sink body having an upward peripheral wall, an upper heat sink body mounted in said lower heat sink body and fixedly fastened to the upward peripheral wall of said lower heat sink body, an airtight chamber defined in between said upper heat sink body and said lower heat sink body, a working fluid filled in said airtight chamber, a porous structure formed in said upper heat sink body and said lower heat sink body inside said airtight chamber, and a solder soldered to said upper heat sink body and the peripheral wall of said lower heat sink body.  
     
     
         2 . The heat sink as claimed in  claim 1 , wherein said upper heat sink body comprises a downward peripheral wall inserted into said lower heat sink body and spaced from the upward peripheral wall of said lower heat sink body at a distance within which said solder is inserted, the downward peripheral wall of said upper heat sink body having an outward bottom flange soldered to the upward peripheral wall of said lower heat sink body by said solder.  
     
     
         3 . The heat sink as claimed in  claim 1 , wherein said porous structure is formed of a metal powder in said upper heat sink body and said lower heat sink body by sintering under the presence of a reduction gas.  
     
     
         4 . The heat sink as claimed in  claim 1 , wherein said porous structure is formed of a metal powder in said upper heat sink body and said lower heat sink body by sintering under the presence of an inert gas.  
     
     
         5 . The heat sink as claimed in  claim 3 , wherein said metal powder is selected from copper powder, nickel powder, and silver powder, and their compound and alloy powder.  
     
     
         6 . The heat sink as claimed in  claim 4 , wherein said metal powder is selected from copper powder, nickel powder, and silver powder, and their compound/alloy powder.  
     
     
         7 . The heat sink as claimed in  claim 1 , wherein said porous structure has a thickness about 2˜10 times of the radius of powder of said metal power.  
     
     
         8 . The heat sink as claimed in  claim 1 , wherein said upper heat sink body and said lower heat sink body each have a coarsened inside wall forming said porous structure.  
     
     
         9 . The heat sink as claimed in  claim 1 , wherein the filling amount of said working fluid in said airtight chamber is about 0.5˜2 times of the total space of pores in said porous structure.  
     
     
         10 . The heat sink as claimed in  claim 1 , wherein said airtight chamber has a pressure within the range of 100 torr to 1×10−3 torr.  
     
     
         11 . The heat sink as claimed in  claim 1  further comprising a suction tube disposed at one side in communication with said airtight chamber and adapted for drawing air out of said airtight chamber.  
     
     
         12 . The heat sink as claimed in  claim 1  further comprising a circulation tube protruded from one side thereof, said circulation tube having two distal ends disposed in communication with said airtight chamber.  
     
     
         13 . The heat sink as claimed in  claim 1 , wherein said upper heat sink body and said lower heat sink body are made of metal material selected from copper, aluminum, and their alloys.  
     
     
         14 . The heat sink as claimed in  claim 1 , wherein said solder is silver solder.  
     
     
         15 . The heat sink as claimed in  claim 1 , wherein said solder is copper solder.  
     
     
         16 . The heat sink as claimed in  claim 1 , wherein said solder is nickel solder.  
     
     
         17 . The heat sink as claimed in  claim 1 , wherein said solder is tin solder.