Dry etch performance of Novolak-based negative e-beam resist

Abstract

Electron beam lithography (EBL) is pivotal for micro- and nanoscale fabrication, offering sub-micron precision. This study explores the utilization of the Novolac-based negative resist AR-N 7520 for EBL and its potential as an etch mask for reactive ion etching (RIE) of silicon. Recent comparisons of negative EBL resists have revealed promising results for AR-N 7520 in terms of resolution and adaptability with other lithography techniques. In this article, we conduct an exploration of patterning of AR-N 7520 (new) for EBL, addressing key parameters in achieving optimal patterning fidelity. Furthermore, we investigate its compatibility with RIE processes, aiming to provide insights into its effectiveness as an etch mask for creating sub-micron silicon structures. Experimental results show that optimal e-beam dose with 100 kV exposure is 300–350 μC/cm². Selectivity of around 9:1 can be achieved by optimizing etching parameters for a continuous etch and higher than 14:1 for a cyclic etch process.