Test structures for residual stress monitoring in the integrated CMOS-MEMS process development

The design of a set of test structures required to monitoring the residual stress and residual stress gradient in the development of a fabrication process that merges electronic and mechanical devices is presented. The microstructures designed have the advantage to be functional with different structural materials like polysilicon, aluminum and titanium. Beam theories have been used to obtain a wide range strain monitoring ranging from 5 MPa until more than 50 MPa. The designed test structures were validated by a finite element analysis.