Development of high-throughput fabrication process of HTS SQUID for 51-ch MCG system

A high-throughput high-T_c SQUID fabrication process that can provide the appropriate number of SQUIDs for a 51-channel magnetocardiograph (MCG) has been developed. A new deposition system-based on a pulsed-laser-deposition technique to increase the process throughput in fabricating superconducting YBa₂Cu₃O_y thin films-was developed. In this system, nine superconducting thin films are successively deposited on bicrystal substrates in one deposition sequence. A mask aligner, which was customized for the bicrystal substrate, was also developed. This system enables mask alignment for the bicrystal grain boundary without the need for preprocessing to visualize it. In addition, the magnetometer pattern was designed to improve the yield for magnetometer fabrication. In this directly coupled magnetometer, four SQUIDs were connected with the same pickup coil. Accordingly, the yield of magnetometer could be enhanced by selecting the best SQUID among the four.