Full field measurements of curvature using coherent gradient sensing : application to thin film characterization

This paper introduces coherent gradient sensing (CGS) as an optical, full-field, real-time, non-intrusive and non-contact technique for measurement of curvature and curvature changes in thin film and micro-mechanical structures. The technique is applied to determine components of the curvature tensor field in multilayered thin films deposited on silicon wafers. Curvature field measurements using CGS are compared with average curvatures obtained using high-resolution X-ray diffraction. Finally, examples are presented to demonstrate the capability of CGS in measuring curvature in a variety of thin film and micro-mechanical structures.