Fabrication of large dual-polarized multichroic TES bolometer arrays for CMB measurements with the SPT-3G camera

This work presents the procedures used at Argonne National Laboratory to fabricate large arrays of multichroic transition-edge sensor (TES) bolometers for cosmic microwave background (CMB) measurements. These detectors will be assembled into the focal plane for the SPT-3G camera, the third generatio...

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Bibliographic Details
Published in:Superconductor Science and Technology
Main Authors: Posada, C. M., Ade, P. A. R., Ahmed, Z., Arnold, K., Austermann, J. E., Bender, A. N., Bleem, L. E., Benson, B. A., Byrum, K., Carlstrom, J. E., Chang, C. L., Cho, H. M., Ciocys, S T, Cliche, J F, Crawford, T M, Cukierman, A, Czaplewski, D, Ding, J, Divan, R, de Haan, T, Dobbs, M A, Dutcher, D, Everett, W, Gilbert, A, Halverson, N W, Harrington, N L, Hattori, K, Henning, J W, Hilton, G C, Holzapfel, W L, Hubmayr, J, Irwin, K D, Jeong, O, Keisler, R, Kubik, D, Kuo, C L, Lee, A T, Leitch, E M, Lendinez, S, Meyer, S S, Miller, C S, Montgomery, J, Myers, M, Nadolski, A, Natoli, T, Nguyen, H, Novosad, V, Padin, S, Pan, Z, Pearson, J
Format: Article in Journal/Newspaper
Language:unknown
Published: IOP 2015
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Online Access:https://orca.cardiff.ac.uk/id/eprint/157692/
https://doi.org/10.1088/0953-2048/28/9/094002
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Summary:This work presents the procedures used at Argonne National Laboratory to fabricate large arrays of multichroic transition-edge sensor (TES) bolometers for cosmic microwave background (CMB) measurements. These detectors will be assembled into the focal plane for the SPT-3G camera, the third generation CMB camera to be installed in the South Pole Telescope. The complete SPT-3G camera will have approximately 2690 pixels, for a total of 16 140 TES bolometric detectors. Each pixel is comprised of a broad-band sinuous antenna coupled to a Nb microstrip line. In-line filters are used to define the different bands before the millimeter-wavelength signal is fed to the respective Ti/Au TES bolometers. There are six TES bolometer detectors per pixel, which allow for measurements of three band-passes (95, 150 and 220 GHz) and two polarizations. The steps involved in the monolithic fabrication of these detector arrays are presented here in detail. Patterns are defined using a combination of stepper and contact lithography. The misalignment between layers is kept below 200 nm. The overall fabrication involves a total of 16 processes, including reactive and magnetron sputtering, reactive ion etching, inductively coupled plasma etching and chemical etching.