Boundary characterization of microstructures through thermo-mechanical testing

Abstract

A variety of silicon foundry processes available for microsystem implementation are available at the present time. The manufacturing methods and the associated process tolerances employed at a particular foundry will determine the performance of the finished devices. Moreover, micro-electro-mechanical systems (MEMS) often require processes that are difficult to control. Device-to-device variations can occur even in batch microfabricated systems. One particular limitation of MEMS foundry processes, in general, is associated with non-classical boundary support conditions due to over/under etching of silicon. These non-classical support conditions will affect the static and dynamic performance of the microsystem. This condition has important implications in atomic force microscopy applications where the targeted natural frequencies are given a wide tolerance due in large part to microfabrication limitations. This paper presents the boundary characterization of single crystal silicon microcantilevers through thermo-mechanical testing. A non-contact optical sensing approach is used for the experimentation. The Rayleigh–Ritz energy method incorporating boundary characteristic orthogonal polynomials is used for the prediction analysis.