Application of polyimide to bending-mode microactuators with Ni/Fe and Fe/Pt magnet

摘要

Out-of-plane polyimide (PI) electromagnetic microactuators with different geometries are designed, fabricated and tested. Fabrication of the electromagnetic microactuators consists of 10 μm thick Ni/Fe (80/20) permalloy deposition on PI diaphragm by electroplating process, electroplating of copper planar coil with 10 μm thick, bulk micromachining, and excimer laser selective ablation. They are fabricated by a novel concept to avoid the etching selectivity and residual stress problems during wafer etching. A simulation model is created by ANSYS software to analyze the microactuators. The external magnetic field intensity (H_(ext)) generated by the planar coil is simulated by this software. Besides, to provide bi-directional and large deflection angles of the microactuators, hard magnet Fe/Pt is deposited at low temperature of 300℃ by sputtering onto the PI diaphragm to produce a perpendicular magnetic anisotropic field. This magnetic field can enhance the interaction with H_(ext) to induce attractive and repulsive bi-directional force to provide a larger displacement. The results of the magnetic microactuators with and without hard magnetic are compared and discussed, respectively. The preliminary result reveals that the electromagnetic microactuators with hard magnet exhibit a greater deflection angle than that without one.