A passive gap-spacing control scheme for in-plane nano-precision sensing and positioning applications

Many advanced microsystems rely on nanometer-resolution in-plane motion between two substrates requiring precise control of gap spacing. Accurately maintained gaps may not only provide desired mechanical response but also enable position-sensing and signal transduction between the substrates. A method of passive gap-spacing control using MEMS-fabricated rigid spacers is proposed. A model to design a low-friction and low-wear interface between the sliding substrates is developed. Prototype parts with hard-coated interfaces and with and without lubrication were fabricated and tested. Sliding friction coefficients of less than 0.1 were achieved on prototype parts with boundary lubrication over a million sliding cycles. Wear life of several million sliding cycles is predicted.