Noncontact Quantitative Spatial Mapping of Stress and Flexural Rigidity in Thin Membranes Using a Picosecond Transient Grating Photoacoustic Technique
01 February 2001
This paper describes a pureley optical technique for measuring and spatially mapping out stress and rigidity in thin membranes. Its application to a membrane of aluminum nitride that has significant spatial non-uniformities in its elastic properties demonstrates the method. The attractive features of this technique-fast, non-contacting measurement, good spatial resolution, ability to quantify in-plane anisotropy-make it potentially useful for characterizing elements of microelectromechanical structures, masks for advanced lithography systems, acoustic filters and other devices in which the mechanical properties of membranes are important.