Microscale materials testing using MEMS actuators

Small size scale and high resolutions in force and displacement measurement s make MEMS actuators appropriate for micromechanical testing, in this pape r, for the first time, we present methodologies for uniaxial tensile and ca ntilever bending testing of both micrometer- and submicrometer-scale freest anding specimens using MEMS actuators. We also introduce dry fabrication pr ocesses for the specimens. The methodologies allo tv freestanding single or multilayered thin-film specimens to be fabricated separately from the MEMS actuators. For the uniaxial tension test, tensile forces are applied by la teral comb drive actuators capable of generating a total load of 383 muN at 40 V with resolutions on the order of 3 nN. A similar actuator is used in the bending test, with load resolution of 58 nN and spring constant of 0.78 N/m. The tensile testing methodology is demonstrated with the testing of a 110-nm-thick freestanding aluminum specimen. The cantilever bending experi ment is performed on a 100-nm-thick aluminum specimen. The experimental set ups can be mounted in a SEM land also in a TEM after modifications for tens ile testing) for in situ observation of materials behavior under different environmental conditions. Remarkable strengthening is observed in all the s pecimens tested compared to their bulk counterparts in both tensile and ben ding experiments. Experimental results highlight the potential of MEMS actu ators as a ne rv tool for materials research.