Design and fabrication of electromagnetic micro-relays using the UV-LIGA technique
type: CreativeWork
description: This dissertation reports a research effort to microfabricate an electromagnetic relay for power applications using a multilayer UV-LIGA process. A mechanically wrapped coil was used and very simple design for the magnetic circuit was adopted to increase the design flexibility and performances. The broad material selection and the capability of making high aspect ratio microstructures of the UV-LIGA make the technology best suited for fabricating microelectromechanical power relays. Fabrication of the device required significant advances in the optical lithography of SU-8 negative photoresist. Research proved that aspect-ratios up to 40:1 in isolated open field structures of thickness between 1 and 1.5 mm can be obtained a standard broadband UV source. The principal factor in this achievement is the reduction of internal stress during the post-exposure bake process that eliminates large plastic deformations present during standard bake procedures. Another challenging issue associated with producing high aspect ratio microstructures is the development narrow groves and deep holes in SU-8 lithography. To overcome this obstacle, megasonic agitation was applied to the developer bath, which resulted in faster development rates, more uniform development, and the ability to produce structures with higher aspect ratios. To date, this process has been used to achieve 100:1 aspect ratio open field features and 45:1 intact cylinder arrays. A multi-layer SU-8 optical lithography and metal electrodeposition process was developed to fabricate the relay. The design required implementation of high aspect ratio lithographic processing techniques to produce a tall nickel magnetic core and insulated magnetic cup in which a pre-wrapped solenoid would be placed for electromagnetic driving. After insertion of the solenoid a Ni-Fe actuator was bonded to the relay base to complete the device. To better understand the fatigue life of electroplated microstructures, a theoretical model was de…
abstract: This dissertation reports a research effort to microfabricate an electromagnetic relay for power applications using a multilayer UV-LIGA process. A mechanically wrapped coil was used and very simple design for the magnetic circuit was adopted to increase the design flexibility and performances. The broad material selection and the capability of making high aspect ratio microstructures of the UV-LIGA make the technology best suited for fabricating microelectromechanical power relays. Fabrication of the device required significant advances in the optical lithography of SU-8 negative photoresist. Research proved that aspect-ratios up to 40:1 in isolated open field structures of thickness between 1 and 1.5 mm can be obtained a standard broadband UV source. The principal factor in this achievement is the reduction of internal stress during the post-exposure bake process that eliminates large plastic deformations present during standard bake procedures. Another challenging issue associated with producing high aspect ratio microstructures is the development narrow groves and deep holes in SU-8 lithography. To overcome this obstacle, megasonic agitation was applied to the developer bath, which resulted in faster development rates, more uniform development, and the ability to produce structures with higher aspect ratios. To date, this process has been used to achieve 100:1 aspect ratio open field features and 45:1 intact cylinder arrays. A multi-layer SU-8 optical lithography and metal electrodeposition process was developed to fabricate the relay. The design required implementation of high aspect ratio lithographic processing techniques to produce a tall nickel magnetic core and insulated magnetic cup in which a pre-wrapped solenoid would be placed for electromagnetic driving. After insertion of the solenoid a Ni-Fe actuator was bonded to the relay base to complete the device. To better understand the fatigue life of electroplated microstructures, a theoretical model was de…
author: Williams, John Dalton
keywords: MEMS, fracture mechanics, UV-LIGA, power relay, SU-8, electromagnetic relay
date published: 2004-01-01T08:00:00Z
date modified: 2026-07-24T02:58:40Z
provider: Lousiana State University
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: Engineering Science (Interdepartmental Program)

PropertyValue
property ID: DOI
value: 10.31390/gradschool_dissertations.970