Micro-raman measurement of bending stresses in micromachined silicon flexures

Micron-scale characterization of mechanical stresses is essential for the successful design and operation of many micro-machined devices. Here we report the use of Raman spectroscopy to measure the bending stresses in deep reactive-ion etched silicon flexures with a stress resolution of similar to10 MPa. and spatial resolution of similar to 1 mum. The accuracy of the technique, as assessed by comparison to analytical and finite-element models of the deformation, is conservatively estimated to be 25 MPa. Implications for the use of this technique in microsystems design are discussed.