Mechanical behavior of microstrip structures made from YBa/sub 2/Cu/sub 3/O/sub 7-x/ superconducting ceramics

The thermal stress response of YBa/sub 2/Cu/sub 3/O/sub 7-x/ superconducting microstrip lines on GaAs, Si, Al/sub 2/O/sub 3/, and MgO dielectric substrates has been studied using the finite-element method. Detailed stress distributions near critical areas of the systems were calculated to understand the mechanical behavior of the composite. The resulting stress fields are very high (large enough to cause cracking in the composite structure) for some of the dielectric materials due to the thermal expansion mismatch between the superconducting material and the dielectric substrate. YBa/sub 2/Cu/sub 3/O/sub 7-x/ superconducting microstrip lines on MgO displayed the best thermal-mechanical properties. It is concluded that the management of stresses resulting from the operating thermal environment will be a critical design constraint for the manufacture of reliable superconductor interconnects.<>