DICARBOXYLIC-ACID-BASED AND TRICARBOXYLIC-ACID-BASED ETCHES FOR PROCESSING HIGH-TEMPERATURE SUPERCONDUCTING THIN-FILMS

The development of passive and active electronics from high temperatur e superconducting thin films depends on the development of process tec hnology capable of producing appropriate feature sizes without degradi ng the key superconducting properties. We present a new class of chela ting etches based on di- and tricarboxylic acids that are compatible w ith positive photoresists and can produce submicrometer feature sizes while typically producing increases the microwave surface resistance a t 94 GHz by less than 10%. This simple etching process works well for both the Y-Ba-Cu-O and Tl-Ba-Ca-Cu-O systems.