Shallow pattern generation in poly(methylmethacrylate)(PMMA) using low-energy electron beam

Abstract

Low-energy electron beam lithography has been of great interest to researchers, because it could provide a good solution to improve throughput, and reduce substrate damages. The main issues of low-energy electron beam lithography are the reliability of resist and the developing conditions. In this paper, we have investigated the developed pattern depth profile in poly(methylmethacrylate) (PMMA) using microcolumn electron beam source with an accelerating voltage of 500 eV. The dose latitudes of samples were varied from 10 μC/cm2 to 90 μC/cm2, and the developing time varied from 10 sec to 60 sec. We also varied the concentration of isopropanol(IPA) in DI water for developer(IPA:DI = 1:1 and 3:7). We investigated the depth profiles and the edge roughnesses with atomic force microscope(AFM) and scanning electron microscope(SEM).