Resist Exposure Characteristics by a Focused Low Energy Electron Beam

Abstract

Resist exposure characteristics by focused low energy electron beam (E‐beam) were studied from the viewpoint of nanometer scale pattern delineation. Single layer positive resist and multilayer negative resist were exposed with 1–20 kV electron beam. As the electron energy decreased, the penetration depth in a resist layer reduced, resulting in incomplete development of the single layer resist with a practical thickness. Resist sensitivity and proximity effect were considerably improved by decreasing the voltage. Fine patterning can be carried out in a multilayer resist process, because a top imaging layer can be very thin, but resist scums formed probably due to the charging‐up effect of low energy electrons. The charging‐up problem can be completely solved by applying a novel 2‐layer conducting resist system, and nanometer patterns as small as 40 nm were obtained with 2–5 kV exposure.