MEMS based micro vapor compression refrigeration system for microelectronic and photonic thermal control

Abstract

A micro-refrigerator is fabricated using Micro-Electro Mechanical Systems processing and is used to thermally control photonic or microelectronic circuits. Temperatures below local ambient are possible due to the refrigeration capability of the device and unwanted parasitic heat such as from the walls or lid of an enclosure is minimized due to the small size of the cooled mounting area for the integrated circuit. Localized cooling is provided by jets of vapor droplet mixture controlled to impinge directly onto the hottest regions of a microelectronic or photonic integrated circuit allowing greater circuit density and thermal dissipation at isolated regions within the integrated circuit and advantageously improving performance. Methods of manufacturing micro-scale refrigerator elements including the compressor, evaporator and condenser are defined. This device is a direct improvement over the commonly used thermoelectric cooler for thermal control of microelectronic or photonic devices.

1 . A micro-refrigerator operating on the vapor compression refrigeration cycle that is less than 10 mm×10 mm×1.5 mm in size and is fabricated using MEMS processes.  
   
   
       2 . The evaporator section substantially as shown in  FIG. 4  allowing the direct mounting of photonic or microelectronic integrated circuit chip for cooling.  
   
   
       3 . The evaporator arrangement of  claim 2  wherein the interior of the chamber is provided with etched fins for efficient heat transfer to the refrigerant.  
   
   
       4 . The evaporator arrangement of  claim 2  wherein the coolant is supplied in multiphase droplet/vapor mixture for greatly enhanced heat transfer and advantageously smaller evaporator volume.  
   
   
       5 . The evaporator section of  claim 2  wherein the embodiment of the chamber is thermally insulated by air and glass to prevent parasitic thermal leakage to the surrounding material.  
   
   
       6 . The condenser section substantially as shown in  FIG. 4  with extended surface fins for minimum condenser volume and allowing dissipation of heat to the surroundings.  
   
   
       7 . The condenser section of  claim 6  wherein the heat exchanger is thermally attached to a heat sink to aid in thermal dissipation to the surrounding ambient.  
   
   
       8 . The condenser section of  claim 6  wherein the multiphase heat transfer to the condenser surface minimizes the condenser volume.  
   
   
       9 . A compressor section that is fabricated with MEMS processes allowing the piezoelectric, electromagnetic or thermal actuation to compress the refrigerant fluid to working pressure.  
   
   
       10 . The compressor section of  claim 7  wherein the compressor is actuated by a piezoelectric polymer such as PVDF arranged in a bimorph construction with metalization allowing a peristaltic pumping action with so sliding contact parts minimizing wear.  
   
   
       11 . MEMS etched interconnecting piping allowing the refrigerant to circulate between the evaporator, compressor, condenser and expander orifice.  
   
   
       12 . MEMS etched orifice in the interconnecting piping of  claim 11  wherein the pressure drop is regulated to the evaporator chamber.  
   
   
       13 . A plenum chamber arrangement as illustrated in  FIG. 5  that provides localized cooling jets of refrigerant to the hottest regions of the photonic or microelectronic integrated circuit chip.  
   
   
       14 . The micro-refrigerator of  claim 1  wherein the compressor section is operated in reverse to provide heating to the photonic or microelectronic integrated circuit chip.  
   
   
       15 . The micro-refrigerator of  claim 1  wherein the mounting location for the photonic or microelectronic chip is provided with an electrical resistance heater to allow independent control of the chip temperature without changing the refrigerator operating parameters.