5-MU-M-WIDE YBA2CU3O7-DELTA COPLANAR LINE WITH LOW TRANSMISSION LOSS

Narrow and low-loss YBa2Cu3O7-delta (YBCO) transmission lines for use in multichip modules have been attempted to be developed. 18-cm-long Y BCO coplanar transmission lines with widths down to 5 mu m were prepar ed by a composite patterning process combining Ar-ion milling and wet- etching. The transmission losses of the packaged 5-, 10-, and 25-mu m- wide lines, respectively, were -1.57, -0.85, and -0.55 dB at 20 GHz an d 55 K. These values provide similar surface resistances of 0.59-0.80 m Omega at 20 GHz and 55 K. This indicates successful fabrication of a 5-mu m-wide YBCO coplanar line without notable extrinsic loss increas e resulting from process damage. The attenuation constants of these li nes are approximately two orders of magnitude lower than for 10-mu m-w ide Cu microstrip lines. These results show that the YBCO coplanar lin es with widths down to 5 mu m have great potential for use in multi-ch ip modules. (C) 1997 American Institute of Physics.