The Development of Polymer-Based Planar Microcryogenic Coolers

• Published in: Journal of microelectromechanical systems 2013-02, Vol.22 (1), p.244-252
• Main Authors: Yunda Wang, Lewis, R., Lin, M. M.-H, Radebaugh, R., Lee, Y. C.
• Format: Article
• Language: English
• Subjects: Exact sciences and technology; Fabrication; Glass; Heat exchanger (HX); Heating; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; Mechanical instruments, equipment and techniques; microcryogenic cooler (MCC); Micromechanical devices and systems; mixed refrigerant; Physics; planar; polyimide; Polyimides; Silicon; Valves; wafer-level process
• ISSN: 1057-7157; 1941-0158
• DOI: 10.1109/JMEMS.2012.2227461

In this paper, polymer-based microcryogenic cooler (MCC) cold stages, each with a footprint of 17 mm × 5 mm, have been successfully developed and tested. The MCC cold stage consists of a polyimide heat exchanger (HX) which is monolithically manufactured on a silicon substrate by using a polyimide/copper microelectromechanical systems process and a silicon/glass Joule-Thomson (J-T) valve which is formed with anodic bonding. Specifically, PI-2574 (HD MicroSystems) was used to make the HX in this work. The two parts are assembled together, forming a cooler which uses the J-T cycle. A cooling test with an optimized five-component mixture as the refrigerant was conducted to examine the performance of the cooler. The cooling temperature was able to reach 233 K under an operating pressure ratio of 0.7:0.15 MPa. It is one of the world's smallest J-T cold stages and the first one fabricated and assembled based on wafer-level processes.