AVS 52nd International Symposium
    Thin Films Friday Sessions
       Session TF-FrM

Paper TF-FrM3
A Compliant System of Polyimide Microwires for Cryogenic Detector Applications

Friday, November 4, 2005, 9:00 am, Room 306

Session: Thin Films on Flexible and Polymer Substrates
Presenter: C.A. Allen, NASA Goddard Space Flight Center
Authors: C.A. Allen, NASA Goddard Space Flight Center
D. Franz, NASA Goddard Space Flight Center
S.H. Moseley, NASA Goddard Space Flight Center
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We have developed a highly compliant, low thermal conductance system of electrical interconnects for cryogenic detector applications. The arrays of microwires are metallic thin film electrical leads supported by a layer of polyimide, capable of spanning the thermally isolated gap between the detector array and the cryogenic heat sink in cryogenic detector assemblies. The low thermal conductance of the microwires enables cryogenic detector thermal isolation without the need for conventional hard wiring, such as soldered manganin or stainless steel. Designed for compactness, an array of 30 microwires fits on a silicon chip less than one half of one square centimeter in total surface area. The free standing length of our microwires is measured in millimeters, as contrasted by units of microns for conventional air-bridge structures. Microwire arrays are terminated on each end by a solid silicon chip containing wire-bonding pads. The two ends of the chip are temporarily supported by a silicon frame, which is removed by laser dicing after the chip has been applied to the detector's thermal isolation platform. We describe techniques for fabrication of arrays of polyimide microwires with several different types of conductive traces, both superconducting and normal-metal. We will discuss their mechanical, electrical, and thermal properties.