A simple fabrication method for submicron diameter metallic apertures using negative electron beam resist and metal lift-off has been developed. In general, the lift-off process is beneficial for semiconductor quantum dot spectroscopy, since the original surface condition of the substrate is not altered or destroyed as it may be in a conventional dry or wet etching processes to form apertures in a subtractive process. With an optimum combination of process parameters, such as higher pre- and postexposure bake temperatures for longer times, longer developing time and with optimal mixtures of developers, high aspect ratio resist posts were obtained. Using 20 kV single dote-beam exposure, a reentrant profile can be obtained directly. While this profile is not obtained with 50 kV single dote-beam exposure, a higher aspect ratio (∼7:1) and sub-100 nm diam resist posts are possible. High vertical sidewall 100 nm diam resist posts are obtained using 50 kV areae-beam exposures. Taking advantage of these characteristics: high aspect ratio, high vertical resist sidewall, and resist undercut at the bottom of post, sub-100 nm diam apertures in 100 nm thick metallic films are obtained by evaporation of metal on the sample and dissolving the resist post in solvent. For sub-100 nm apertures, a significant improvement in aperture edge smoothness was achieved by applying an oxygen plasma.