Biaxial initial stress characterization of bilayer gold RF-switches

An analysis as been conducted to determine the biaxial initial stress state of gold bilayer switches. Results are shown that the sensitivity of the sacrificial photoresist layer to process parameters make the wafer curvature technique unreliable to determine the initial stress state of the evaporated gold seed layer. An analytical method based on the cantilever deflection method is proposed to determine the biaxial stress state on this layer. Assumptions were validated numerically using FEM and cantilevers gold bilayer of various length were elaborated and characterized.