A Polymeric SU-8 Micro-Twezer with In-Plane Double Action Based on Chevron Actuators

The paper presents the design, simulations, fabrication and experimental characterization results of a micro-tweezer with in-plane double action of the arms in order to obtain a double movement of the micro-tweezer free arms, for opening but also for closing the tips. In order to obtain this movement, the micro-tweezer is electro-thermally actuated using four pairs of chevron actuators, two for closing the arms and two for opening. The structure was fabricated using the SU-8 polymer as structural material. The micro-tweezer was simulated using the finite element method within Coventorware software in order to determine the electro-thermo-mechanical behavior. Electro-mechanical measurements and characterizations have been performed to determine the double action (open and close) of the micro-tweezers tips as a function of electrical current. The measurements show a maximum in-plane opening of the micro-tweezer tips of $\sim 230\ \mu \mathrm{m}$ for an electrical current of 115 mA, and a full closing of the arms of $60\ \mu \mathrm{m}$ at 195 mA.