Design and Fabrication of Robust High Performance Piezoelectric Micro-Devises.

Piezoelectric;Micro-device;Robust Finite-time Transient Response;Thin-film PZT;Microfabrication;Mechanical Engineering;Engineering;Mechanical Engineering

Rhee, Choong-HoKurabayashi, Katsuo ;

University of Michigan

关键词: Piezoelectric;    Micro-device;    Robust Finite-time Transient Response;    Thin-film PZT;    Microfabrication;    Mechanical Engineering;    Engineering;    Mechanical Engineering;   

Others  :  https://deepblue.lib.umich.edu/bitstream/handle/2027.42/93947/chrhee_1.pdf?sequence=1&isAllowed=y

瑞士|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

Two research tasks are performed to achieve robust fabrication and uniform dynamic performance of complex piezoelectric micro-electromechanical systems: first, production of complex thin-film lead-zirconate-titanate (PZT) microdevices requiring high-yield chip-level process robustness; second, design for feature-level parametric robustness that improves the finite-time dynamic performance uniformity of piezo-MEMS devices.Thin-film PZT actuators are integrated in a robust way with silicon microstructures via the latter’s encapsulation by vertical silicon dioxide barrier trenches.The process conserves piezoelectric performance with high actuator yield and supports multi-level structure fabrication. Two prototype devices that take advantage of this process to produce multiple-degree-of-freedom motions and large displacements with fast response times are characterized experimentally. For the first prototype, a micro-robotic leg joint, displacement modeling is performed that includes compensation for intrinsic residual stress of thin-film stacks, oxide barrier trench properties as they influence behavior of in-plane flexure joint arrays, and the stiffness of an electrical interconnect structure across compact actuator arrays. The modeling approach and empirical measurements show good agreement for multi-degree-of-freedom static displacements. For the second prototype, a vertical translational z-axis focusing stage for endoscopic microscopes, the fabrication process allows backside etching to release stages actuated by multi-fold thin-film PZT vertical actuators. Motion generated by the proposed vertical translational z-axis focusing stage is targeted up to 200 micron, and the transient response of two-fold stage is shown and found to be faster than other existing actuation mechanism of endoscopic micro-mirror platform.For design of robust finite-time transient response of piezoelectric MEMS devices the maximum perturbed finite-time transient behavior of the system is represented by the spectral radius of a compact matrix. This allows efficient optimization of the worst-case scenario for perturbed finite-time transient response. In case studies, locally optimal structural parameters of piezoelectric micro-electromechanical systems were obtained. Using mu-synthesis analysis, the maximum perturbation is estimated systematically when compared to randomly generated samples, which may not guarantee the maximum perturbed finite-time transient response.