This research will explore a new etching technique called aerosol jet etching for use in integrated circuit manufacture. In this technique, submicron droplets of etchant freshly formed from the vapor state are deposited on the substrate to be etched. The etching of silicon with hydrofluoric - nitric acid droplets and the etching of gallium arsenide with bromine - ethanol droplets will be studied experimentally. Attention will be directed to the anisotropy of etching and the level of resolution achievable. Parts of the process will be modelled mathematically. The research will also explore the use of electrically charged clusters consisting of several thousand etchant molecules as a hybrid of aerosol jet etching and focussed ion beam etching in order to achieve very high resolution. Aerosol jet etching combines several advantages of wet and dry etching while avoiding some of their respective disadvantages. In particular, very small contamination, good anisotropy of etching, and adequate line width resolution are achievable. Use of charged clusters promises to achieve even finer line width resolution.
