Wafer-level processing for polymer-based planar micro cryogenic coolers

In this paper, we present the fabrication and testing of a novel polymer-based Joule-Thomson (J-T) micro cryogenic cooler (MCC). Techniques including monolithic fabrication of high pressure polymer channels and 3-D interconnect for fluid channels including a flow resistance are developed to fabricate a planar MCC. The MCC contains a polymer heat exchanger and a silicon/glass J-T valve. A low temperature of 233 K was achieved under an operation pressure ratio of 0.7:0.15 MPa by using a custom designed mixed refrigerant. It is the first demonstration ever reported for J-T MCCs fabricated and assembled based on wafer-level processes.