Fabrication of electrostatic nickel microrelays by nickel surface micromachining

This paper reports preliminary results on the development of lateral-motion electrostatic nickel microrelays. The devices, up to 15 pm thick, were fabricated in a new surface micromachining process, using electroless plated nickel as the structural material, high-aspect-ratio positive resist lithography for the plating mold, and polysilicon as the sacrificial layer. Planar microrelays were fabricated and mechanically actuated to investigate electrical contact attributes. Initial experiments revealed contact resistances to be lower than 20R (even as low as 5R) and contact current loads up to 150mA without degradation. The Young’s modulus and residual stress of electroless nickel films, determined using mechanical test structures microfabricated alongside the microrelays, were found to be 154 GPa and 89 MPa, respectively.

[1]  K. Petersen.  Micromechanical membrane switches on silicon , 1979 .

[2]  In Situ Measurement of Young’s Modulus and Residual Stress of Thin Electroless Nickel Films for Mems Applications , 1994 .

[3]  C. Linder,et al.  Electrostatic polysilicon microrelays integrated with MOSFETs , 1994, Proceedings IEEE Micro Electro Mechanical Systems An Investigation of Micro Structures, Sensors, Actuators, Machines and Robotic Systems.

[4]  Nickel surface micromachining , 1995, MHS'95. Proceedings of the Sixth International Symposium on Micro Machine and Human Science.

[5]  Hiroshi Hosaka,et al.  Electromagnetic microrelays: concepts and fundamental characteristics , 1993, [1993] Proceedings IEEE Micro Electro Mechanical Systems.

[6]  M. Sakata.  An electrostatic microactuator for electro-mechanical relay , 1989, IEEE Micro Electro Mechanical Systems, , Proceedings, 'An Investigation of Micro Structures, Sensors, Actuators, Machines and Robots'.