Characterization of resist profiles using water enhanced focused ion beam micromachining

The use of water enhanced focused ion beam micromachining has been investigated as a technique to aid in the characterization of resist profiles. The increase in removal rate and the decrease in redeposition associated with the water enhancement allows clean cross sections (no redeposition of substrate material) to be formed at precise locations allowing accurate resist sidewall characterization and eliminates the need for wafer cleaving. The experimental conditions (water flux and beam exposure parameters) were optimized to produce cross sections with minimum artifacts. It was found that water pressure of approximately 80 mTorr, line step distances corresponding to half the beam diameter and dwell time roughly twice that required to clear the resist resulted in nearly vertical cross section faces with minimum edge artifacts.