Variable pressure electron beam lithography (VP-eBL): A new tool for direct patterning of nanometer-scale features on substrates with low electrical conductivity

We introduce variable pressure electron beam lithography (VP-eBL), as a new approach for the fabrication of nanometer-scale structures on electrically insulating substrates. This novel approach combines the high-resolution patterning capability of electron beam lithography with the charge-balance mechanism of the variable pressure scanning electron microscope (VPSEM) to control charging effects during pattern exposure. VP-eBL eliminates the need for any of the additional materials or processing steps required to eliminate pattern distortion artifacts during high vacuum eBL patterning on such substrates. Preliminary characterization of the VP-eBL process is presented, which demonstrates no significant change in ultimate pattern definition or enhancement of the local proximity effects due to primary beam scattering. In addition, we find that the shape of the scattering profile in the resist layer is modified in the presence of the chamber gas, allowing improved pattern definition at higher pressures.