Liquid cooled compliant heat sink and related method

Abstract

A heat sink and method for using the same for use in cooling an integrated circuit (IC) chip is provided herein. The heat sink includes a manifold block, a liquid-filled cooling system, and a compliant foil affixed to the manifold block and backed by a liquid in the closed loop cooling system. The pressure provided by the liquid behind the foil causes the foil to bow, and to conform to non-planarities in the surface of the IC chip, thus reducing air gaps and increasing thermal coupling between the IC chip and the heat sink.

1 . A method including:
 providing an integrated circuit (IC) chip;   providing a heat sink including a variable volume liquid-filled chamber within the heat sink and a thermally conductive, compliant foil backed by a liquid in the variable volume liquid-filled chamber;   thermally coupling the IC chip with the heat sink, the thermal coupling including
 pressurizing the compliant foil with the liquid in the variable volume liquid-filled chamber, and 
 conforming the compliant foil to a surface of the IC chip; and 
   cooling the IC chip, wherein heat is conducted from the IC chip to the compliant foil, and from the compliant foil to the liquid in the variable volume liquid-filled chamber.   
     
     
         2 . The method of  claim 1 , further including circulating the liquid through the heat sink in a closed loop, wherein the circulating includes:
 chilling the liquid in a refrigerated recirculator prior to passing the liquid into the heat sink;   passing the liquid into the variable volume liquid-filled chamber in the heat sink via an input port in the heat sink; and   returning the liquid from the variable volume liquid-filled chamber in the heat sink via a return port in the heat sink.   
     
     
         3 . The method of  claim 2 , the circulating further including passing the liquid through the variable volume liquid-filled chamber in the heat sink, wherein the variable volume liquid-filled chamber includes:
 an elastomeric material member including a through-port; and   a mesh member including a coarse mesh member and a fine mesh member,   wherein the mesh member is adjacent to the compliant foil, the mesh member being configured such that the fine mesh member is located between the compliant foil and the coarse mesh member, and the elastomeric material member is adjacent to the coarse mesh member, and   wherein the liquid enters the heat sink via the input port, passes through the through-port, into the mesh member, and exits the heat sink via the return port.   
     
     
         4 . The method of  claim 2 , the circulating further including passing the liquid through the variable volume liquid-filled chamber in the heat sink, wherein the variable volume liquid-filled chamber includes:
 a microjet device including a plurality of supply jets for introducing the liquid behind the compliant foil at a pressure, and a plurality of drains for returning the liquid to the closed loop liquid-filled cooling system.   
     
     
         5 . The method of  claim 1 , further including passing the liquid through the heat sink in an open loop, the open loop including:
 an input port for liquid to enter the variable volume liquid-filled chamber in the heat sink; and   a return port for liquid to exit the variable volume liquid-filled chamber in the heat sink.   
     
     
         6 . The method of  claim 1 , wherein the variable volume liquid-filled chamber comprises a static, liquid-filled bladder, and wherein the heat sink further includes a means for cooling the heat sink. 
     
     
         7 . The method of  claim 1 , wherein the compliant foil comprises BeCu. 
     
     
         8 . The method of  claim 1 , further including using a liquid thermal interface (LTI) between the heat sink and the IC chip. 
     
     
         9 . A heat sink for cooling an integrated circuit (IC) chip, the heat sink comprising:
 a liquid-filled cooling system including a variable volume liquid-filled chamber; and   a thermally conductive, compliant foil backed by a liquid in the variable volume liquid-filled chamber, wherein a pressure of the liquid on the compliant foil provides a uniform pressure by the foil against the IC chip and causes the compliant foil to conform to a surface of the IC chip.   
     
     
         10 . The heat sink of  claim 9 , wherein the liquid-filled cooling system comprises a closed loop, the closed loop including:
 a refrigerated recirculator for chilling the liquid prior to circulating the liquid through the heat sink;   an input port for liquid to enter the variable volume liquid-filled chamber in the heat sink; and   a return port for liquid to exit the variable volume liquid-filled chamber in the heat sink.   
     
     
         11 . The heat sink of  claim 10 , wherein the variable volume liquid-filled chamber in the heat sink further includes:
 an elastomeric material member including a through-port; and   a mesh member including a coarse mesh member and a fine mesh member,   wherein the mesh member is adjacent to the compliant foil, the mesh member being configured such that the fine mesh member is located between the compliant foil and the coarse mesh member, and the elastomeric material member is adjacent to the coarse mesh member, and   wherein the liquid enters the heat sink via the input port, passes through the through-port, into the mesh member, and exits the heat sink via the return port.   
     
     
         12 . The heat sink of  claim 10 , wherein the closed-loop liquid-filled cooling system further includes a microjet device including a plurality of supply jets for introducing the liquid behind the compliant foil at a pressure, and a plurality of drains for returning the liquid to the closed loop liquid-filled cooling system. 
     
     
         13 . The heat sink of  claim 9 , wherein the liquid-filled cooling system further comprises an open loop, the open loop including:
 an input port for liquid to enter the variable volume liquid-filled chamber in the heat sink; and   a return port for liquid to exit the variable volume liquid-filled chamber in the heat sink.   
     
     
         14 . The heat sink of  claim 9 , wherein the variable volume liquid-filled chamber further comprises a static, liquid-filled bladder, and wherein the heat sink further includes a means for cooling the heat sink. 
     
     
         15 . The heat sink of  claim 9 , wherein the compliant foil comprises BeCu. 
     
     
         16 . The heat sink of  claim 9 , further including a liquid thermal interface (LTI) located between the heat sink and the IC chip. 
     
     
         17 . A method including:
 providing an integrated circuit (IC) chip;   providing a heat sink including a variable volume liquid-filled chamber within the heat sink, and a compliant foil made of BeCu, the compliant foil being backed by a liquid in the variable volume liquid-filled chamber,   thermally coupling the IC chip with the heat sink, wherein the thermal coupling includes
 pressurizing the compliant foil with the liquid in the variable volume liquid-filled chamber, and 
 conforming the compliant foil to a surface of the IC chip; and 
   circulating the liquid through the heat sink in a closed loop, the circulating including
 chilling the liquid in a refrigerated recirculator prior to passing the liquid into the heat sink; 
 passing the liquid into the variable volume liquid-filled chamber in the heat sink via an input port in the heat sink; and 
 returning the liquid from the variable volume liquid-filled chamber in the heat sink via a return port in the heat sink. 
   
     
     
         18 . The method of  claim 17 , the circulating further including passing the liquid through the variable volume liquid-filled chamber in the heat sink, wherein the variable volume liquid-filled chamber further includes:
 an elastomeric material member including a through-port; and   a mesh member including a coarse mesh member and a fine mesh member,   wherein the mesh member is adjacent to the compliant foil, the mesh member being configured such that the fine mesh member is located between the compliant foil and the coarse mesh member, and the elastomeric material member is adjacent to the coarse mesh member, and   wherein the liquid enters the heat sink via the input port, passes through the through-port, into the mesh member, and exits the heat sink via the return port.   
     
     
         19 . The method of  claim 17 , the circulating further including passing the liquid through the variable volume liquid-filled chamber in the heat sink, wherein the variable volume liquid-filled chamber further includes:
 a microjet device including a plurality of supply jets for introducing the liquid behind the compliant foil at a pressure, and a plurality of drains for returning the liquid to the closed loop liquid-filled cooling system.   
     
     
         20 . The method of  claim 17 , wherein the compliant foil conforms completely to the surface of the IC chip.