Optical DUV-lithography for high microstructures

Abstract

A new technology called 3D UV-Microforming consisting of an advanced resist preparation process, a UV lithographic step, resist development, a moulding procedure by electrodeposition, and finally stripping and cleaning for finishing the structures was developed for application in microsystem technology. It enables the low-cost fabrication of a wide variety of micro components for many different users. During resist preparation, layers up to two hundred μm thickness were obtained until now. By using a standard UV mask aligner as an exposure tool followed by immersion development, thick resist layers up to 100 μm could be patterned in a single step on pre-processed silicon wafers. Repeated exposure and development were successfully used for structuring resist layers of up to 200 μm thickness. High aspect ratios of more than 10 as well as steep edges of more than 88° could be fabricated. The resist patterns were moulded by using pulse or DC electroplating. For microsystem applications some metals and alloys were deposited, Three-dimensional micro components were fabricated as demonstrators for the new technique. It allows the use of materials with interesting properties which could not be provided by standard processes.