Macro LIGA fabrication of mechanical structures

The recent development in microelectromechanical systems (MEMS) and ultra-deep x-ray lithography has sparked interests from many parties, including the precision manufacturing community. As a result, the LIGA process (i.e. the German acronym of Lithographic, Galvanoformung, Abformung) has become one of the frequently employed techniques for producing high precision and high aspect ratio structures. While other researchers have been focusing on making high aspect ratio parts, the research presented in the dissertation investigates primarily the process precision of macro LIGA fabrication.; A mathematical modeling framework was first developed to estimate error generation during the ultra-deep synchrotron x-ray lithography process. Simulation of exposure image formation of highly complex geometry such as the involute gear tooth was then presented to demonstrate the pattern transfer accuracy of the x-ray lithography process. Material selection and fabrication process of the x-ray mask was also examined with regard to their impact on process errors.; A number of empirical models relating process error modes to their error sources were developed for the x-ray lithography, PMMA (i.e. polymethyl-methacrylate) development, and electroplating process. Experiment data in PMMA swelling behavior and process parameters of PMMA development and electroplating were also presented to support the error models.; The methodology of error budget analysis was employed to unify various process error models presented in the dissertation. Such issues as error directionality, error sensitivity, error propagation and compensation etc. were thoroughly investigated through both qualitative and quantitative analysis. The fabrication of and metrological measurements on components of a micro step motor were presented to demonstrate error analysis of the macro LIGA process, as well as the feasibility of using the process as an alternative precision manufacturing technique.