ULTRAVIOLET DEPTH LITHOGRAPHY AND GALVANOFORMING FOR MICROMACHINING

For advanced surface micromachining 3D UV-microforming delivers excell ent results. This low-cost technology, a combination of UV patterning of very thick photoresist layers and molding of the resulting patterns by galvanoplating, opens a wide range of applications. An advanced sp in coating and drying process was developed, which allows the homogene ous deposition of photoresist layers up to more than 60 mu m in a sing le step. Simply by exposure to standard UV aligners and following imme rsion development, thick photoresist layers up to 100 mu m could be pa tterned. Repeated exposures and developments were successfully used fo r structuring resist layers of more than 100 mu m thickness. High aspe ct ratios of more then 10 and steep edges of more than 88 degrees were achieved. The resist patterns were molded by electroplating. The wide ly used gold and nickel were completed by copper, zinc, and magnetic a lloys like NiFe. If combined with sacrificial layers, this new techniq ue offers a wide field for smart processing from the micron to the mil limeter range. 3D UV-microforming allows the use of materials with int eresting properties which could not be provided by standard processes. It opens a way for faster acceptance of microfabrication In practice.