Thermally conductive channel between a semiconductor chip and an external thermal interface

Abstract

An apparatus is described comprising a chamber containing liquid. A side of the chamber is thermally coupled to a semiconductor chip. The side of the chamber has thermally conductive carbon nanotubes oriented perpendicular to the side's surface. The carbon nanotubes transfer heat drawn from the semiconductor chip into the liquid, causing it to boil and spread heat laterally across the top face of the chamber. The top face of the chamber may be thermally connected to an external heat sink if necessary. This device allows for a greatly improved ability to transfer heat from the hot spots of a semiconductor device to the ambient medium.

1 . An apparatus comprising: 
 a chamber containing liquid, a side of said chamber thermally coupled to a semiconductor chip, said side of said chamber having thermally conductive carbon nanotubes oriented perpendicular to said side's surface, said carbon nanotubes to transfer heat drawn from said semiconductor chip into said liquid.    
   
   
       2 . The apparatus of  claim 1  wherein said chamber is comprised of Silicon (Si) or Copper (Cu).  
   
   
       3 . The apparatus of  claim 2  wherein said side is comprised of Si or Cu.  
   
   
       4 . The apparatus of  claim 1  wherein another side of said of chamber is thermally coupled to an external thermal interface of a cooling system of which said chamber is part, said cooling system to transfer said heat to said external thermal interface.  
   
   
       5 . The apparatus of  claim 4  wherein said external thermal interface comprises a heat sink.  
   
   
       6 . The apparatus of  claim 4  wherein said external thermal interface comprises a heat exchanger.  
   
   
       7 . The apparatus of  claim 4  wherein said another side is thermally coupled to said external interface by way of a liquid flow channel that carries warmed liquid from said chamber.  
   
   
       8 . The apparatus of  claim 1  wherein said carbon nanotubes are electrically conductive carbon nanotubes.  
   
   
       9 . A method performed by a semiconductor chip's cooling system, comprising: 
 transferring heat from said semiconductor chip to carbon nanotubes immersed in a liquid, said carbon nanotubes heating said liquid as a consequence;    generating vapor from said liquid as a consequence of said heating; and,    condensing said vapor to transfer at least a portion of said heat to said cooling system's external thermal interface.    
   
   
       10 . The method of  claim 9  wherein said heating and generating takes place in a chamber, said carbon nanotubes attached to a side of said chamber, said side of said chamber thermally coupled to said semiconductor chip.  
   
   
       11 . The method of  claim 10  wherein said heating, generating and condensing takes place in said chamber.  
   
   
       12 . The method of  claim 10  further comprising drawing said liquid from said chamber.  
   
   
       13 . The method of  claim 9  wherein said cooling system's external thermal interface further comprises a heat sink.  
   
   
       14 . The method of  claim 9  wherein said carbon nanotubes are thermally and electrically conductive.  
   
   
       15 . A chamber comprising: 
 walls;    a floor sprouting vertically oriented carbon nanotubes, said walls standing on said floor, said floor thermally coupled to a semiconductor chip;    a ceiling attached atop said walls, said ceiling thermally coupled to an external thermal interface; and,    liquid within the volume bounded by said walls, floor and ceiling.    
   
   
       16 . The apparatus of  claim 15  wherein said chamber is comprised of a material selected from the group consisting of: 
 Silicon (Si); and    Copper (Cu).    
   
   
       17 . The apparatus of  claim 16  wherein said floor is comprised of a material selected from the group consisting of: 
 Silicon (Si); and    Copper (Cu).    
   
   
       18 . The apparatus of  claim 14  wherein said external thermal interface comprises a heat sink.  
   
   
       19 . The apparatus of  claim 15  wherein said carbon nanotubes are electrically and thermally conductive carbon nanotubes.  
   
   
       20 . The apparatus of  claim 15  where the distance between said ceiling and said floor is 150 to 200 μm inclusive.  
   
   
       21 . The apparatus of  claim 15  where said thermal coupling of said ceiling to said external thermal interface further comprises an etched surface of material, another surface of said material used to implement said ceiling, said surface and said another surface on opposite sides of said material.  
   
   
       22 . The apparatus of  claim 15  where said thermal coupling of said ceiling to said external thermal interface further comprises a micro-machined surface of material, another surface of said material used to implement said ceiling, said surface and said another surface on opposite sides of said material.  
   
   
       23 . The apparatus of  claim 15  where said thermal coupling of said ceiling to said external thermal interface further comprises a surface of material coated with metal, another surface of said material used to implement said ceiling, said surface and said another surface on opposite sides of said material.  
   
   
       24 . The apparatus of  claim 23  further comprising an Indium alloy in contact with said metal.  
   
   
       25 . An apparatus, comprising: 
 a) an SRAM semiconductor die;    b) a chamber fixed to said die, said chamber comprising: 
 walls;  
 a floor sprouting vertically oriented carbon nanotubes, said walls standing on said floor, said floor thermally coupled to a semiconductor chip;  
 a ceiling attached atop said walls, said ceiling thermally coupled to an external thermal interface; and,  
 liquid within the volume bounded by said walls, floor and ceiling.  
   
   
   
       26 . The apparatus of  claim 25  wherein said chamber is comprised of a material selected from the group consisting of: 
 Silicon (Si); and    Copper (Cu).    
   
   
       27 . The apparatus of  claim 26  wherein said floor is comprised of a material selected from the group consisting of: 
 Silicon (Si); and    Copper (Cu).    
   
   
       28 . The apparatus of  claim 24  wherein said external thermal interface comprises a heat sink.  
   
   
       29 . The apparatus of  claim 25  wherein said carbon nanotubes are electrically and thermally conductive carbon nanotubes.  
   
   
       30 . The apparatus of  claim 25  where the distance between said ceiling and said floor is 150 to 200 μm inclusive.  
   
   
       31 . The apparatus of  claim 25  where said thermal coupling of said ceiling to said external thermal interface further comprises an etched surface of material, another surface of said material used to implement said ceiling, said surface and said another surface on opposite sides of said material.  
   
   
       32 . The apparatus of  claim 25  where said thermal coupling of said ceiling to said external thermal interface further comprises a micro-machined surface of material, another surface of said material used to implement said ceiling, said surface and said another surface on opposite sides of said material.  
   
   
       33 . The apparatus of  claim 25  where said thermal coupling of said ceiling to said external thermal interface further comprises a surface of material coated with metal, another surface of said material used to implement said ceiling, said surface and said another surface on opposite sides of said material.  
   
   
       34 . The apparatus of  claim 33  further comprising an Indium alloy in contact with said metal.  
   
   
       35 . The apparatus of  claim 25  wherein said chamber is Si—Si fusion bonded to said die.