High Yield Micro Fabrication Process for Biomimetic Artificial Haircell Sensors

We have developed artificial haircell sensors based on an improved plastic deformation magnetic assembly (PDMA) method. The PDMA method is uniquely capable of realizing three-dimensional microstructures in an efficient, ICcompatible manner. We have improved the design of the PDMA structure to significantly increase the yield by eliminating stress concentration. The robustness of the fabricated devices is enhanced using conformal Parylene deposition. The PDMA process uses magnetic force to bend surface micromachined cantilever beams. If the bending is significant, the beams would enter plastic deformation regime and maintains permanently bent position even after the magnetic field is removed. Previously, the PDMA process is associated with appreciable yield loss during the magnetic assembly. The failure mechanism is believed to be stress concentration at sharp corners defined by edges of sacrificial layers. In the new design, a structure enhancement feature is added to the surface micromachined assembly and hence eliminating any sharp features. Haircell sensors are modular sensory units widely found in the biological world. Haircells are responsible for hearing, flow sensing, and for balancing/equilibrium. We are developing artificial haircell sensors using advanced micromachining technology. The artificial haircell sensors have similar physical scale compared with biological ones.