MEMS heat pumps for integrated circuit heat dissipation

Abstract

A cooling mechanism within an integrated circuit includes an internal pump for circulating thermally conductive fluid within closed loop channels. The cooling channels are embedded within an integrated circuit die, such as in interlevel dielectric layers between metal levels. The channels are formed by engineering deposition of a layer to line trenches and form continuous voids along the trenches. Exemplary heat pumps comprise cavities, formed in communication with the channels, covered by piezoelectric actuators; Preferably, the actuators are wired to act in sequence as a peristaltic pump, circulating the fluid within the channels. The channels are positioned to carry heat from active devices within the integrated circuit, and a heat sink carries heat from the die.

1 . A system including an integrated circuit die, comprising: 
 an integrated circuit die;    a closed loop of channels embedded within the integrated circuit die;    a fluid disposed within the channels;    a micromachined pump positioned within the integrated circuit die and configured to circulate the fluid within the channels; and    a heat sink in thermal communication with the die.    
   
   
       2 . The system of  claim 1 , wherein the heat sink comprises copper.  
   
   
       3 . The system of  claim 1 , wherein the heat sink is bonded to the integrated circuit die.  
   
   
       4 . The system of  claim 3 , wherein the heat sink is bonded to an outer surface of the integrated circuit die.  
   
   
       5 . The system of  claim 3 , wherein the heat sink is bonded to the integrated circuit die by a thermally conductive adhesive.  
   
   
       6 . The system of  claim 5 , wherein the adhesive comprises epoxy.  
   
   
       7 . The system of  claim 1 , wherein the heat sink occupies greater than about 80% of the integrated circuit surface area.  
   
   
       8 . The system of  claim 7  wherein the channels are defined by a silicon carbide coating of a plurality of trenches.  
   
   
       9 . The system of  claim 1 , wherein the fluid comprises an inert gas.  
   
   
       10 . The system of  claim 9 , wherein the fluid comprises a thermally conductive noble gas.  
   
   
       11 . The system of  claim 9 , wherein the fluid is selected from the group consisting of argon, helium, krypton and xenon.  
   
   
       12 . The system of  claim 1 , wherein the pump comprises a piezoelectric actuator in communication with the channels.  
   
   
       13 . The system of  claim 12 , further comprising a plurality of piezoelectric actuators arrayed along the channels to form a peristaltic pump.  
   
   
       14 . The system of  claim 12 , wherein the integrated circuit die defines a dynamic random access memory (DRAM) chip.