A high resolution beam scanning system for deep ion beam lithography

The technique of Deep Ion Beam Lithography (DIBL) allows the production of high aspect-ratio microstructures in suitable polymer resists (e.g. PMMA) with complex three-dimensional geometries in a fast, direct write process. In conjunction with micromoulding and electroforming, the DIBL-technique may prove extremely useful for the production of microcomponents, micromachines and microelectromechanical systems (MEMS). The present scanning system (OM-DAQ) in use at the Singapore Nuclear Microscope facility is limited to a 256 x 256 pixels raster scan. This system, while adequate for analytical applications, has limitations when machining high resolution structures using DIBL. A new scanning system has been developed in order to overcome this limitation. The new scanning system is based on a DAC PC-card that allows flexible scanning with a resolution of up to 4096 x 4096 pixels. The new system allows the beam to be scanned in specific patterns, which are designed to achieve optimal resolutions. The use of the new scanning system provides a mechanism for translating high resolution digital images into high resolution three dimensional microstructures. Using this system we have produced submicron (300 nm) walls with an aspect ratio approaching 100, three dimensional complex microstructures with smooth walls and corners, and multiple microstructures exposed by repetitive scanning. (C) 1998 Elsevier Science B.V.