The Role of residual stresses in ceramic substrate materials for hybrid thick film applications

Abstract

This work presents introductory research to provide the relationship between electrical measurements and residual stresses caused by hybrid processing. X-ray diffraction is used to measure residual stresses in the ceramic substrate as well as metallization of wideband coplanar thick film probes. The probes are also tested for electrical performance using Time Domain Reflectometry (TDR) technique. This thesis presents results that indicate that significant tensile residual stresses were generated on the back of the substrate, particularly during the laser scribing phase of the finished device. Significant tensile stresses were also observed in the Silver-Palladium (Ag-Pd) metallization. TDR measurements indicated significant response variations which were attributed to these induced stresses. Attempts were also made to reduce these stresses by an annealing process in order to improve the TDR response uniformity.