A UV-LIGA Microfabricated Electromagnetic Power Relay

Louisiana State University, Baton Rouge LA

Investigators

Abstract

Most micro-sized relays (switches) currently on the market or reported in the literature are solid-state devices made using semiconductor technology, with silicon the predominant material. Such devices are not best suited for applications that require large power capability because they typically have low current capacity, low off-resistance, high on-resistance, high power consumption, and low dielectric strength. In recent years, the fast-evolving technology of microelectromechanical systems (MEMS) has opened up new opportunities for microfabricating microelectromechanical switches. However, most of the MEMS relays are based on silicon fabrication and can not be used for power applications. We propose to design, analyze (model and simulate), microfabricate, and test a new type of micro-relays using electromagnetic actuation. These relays should have the following characteristics: fast switching speed, high power capacity, high off-resistance (completely disconnected), lower on-resistance, and low power consumption and heat generation. Some preliminary study has been conducted and promising results have been obtained on the proposed research work. The proposed micro-relays will be fabricated with UV-LIGA (based on UV lithography) microfabrication technologies. UV-LIGA is based on thick resist (SU-8) and optical lithography, provides slightly lower quality, much shorter time span for development and fabrication, and therefore much lower cost. The LIGA processes provide great potential for building microstructures from a broad selection of materials. Any metals or alloys that can be electroplated could be used as a potential candidate material for three-dimensional MEMS structural components. The combination of a broad material selection and the capability of making high aspect ratio microstructures make the technology best suited for fabricating microelectromechanical relays that can be used in, but not limited to, the applications of high power capacity. For example, good spring materials like beryllium-copper, and good electrically conducting materials including copper and gold can all be electroplated. With improved switching time, the relays may also be used for series sampling with low feedthroughs. Compared with the commonly used electrostatic actuation, the proposed electromagnetic actuation has several advantages: stronger actuation force and potentially higher power capacity, lower possibility of electrostatic sparks