FIB micromachined submicron thickness cantilevers for the study of thin film properties

Submicron thickness single crystal Si cantilevers were fabricated in a focused ion beam (FIB) milling workstation to investigate the mechanical properties of thin films deposited on the completed cantilevers. An order of magnitude reduction in the dimensions and improved control over thickness accomplished with a FIB when compared with conventional lithography and wet etch techniques permits the characterization of mechanical properties on previously unattainable micron and sub-micron scales. Residual compressive stresses within a deposited Al thin film caused a Si cantilever to deflect away from the Si(100) plane of deposition towards the substrate. Deflections were measured for multiple cantilevers and these measurements were used to calculate residual stresses and strains with a modified form of Stoney's equation which yielded stresses of -0.034 to -0.179 GPa and strains of -0.0005 to -0.0025. (C) 2000 Published by Elsevier Science S.A. All rights reserved.