Comprehensive Investigation of the Commercial ELP-20 Electron-Beam Lithography Resist

A systematic experimental study of the positive-tone resist ELP-20 was conducted, covering its structural properties, film-formation behavior, and response to electron-beam exposure. Raman spectroscopy demonstrated the methacrylate nature of the resist and its spectral correspondence to poly(methyl methacrylate) PMMA, which enabled direct comparison both with PMMA itself and with existing methacrylate-based resists. Spin-coated films prepared from 3-11 wt.% solutions exhibited a robust power-law dependence of thickness on spin speed, h_∞ ∝ ω^{-0.48 ± 0.01}, and showed high thickness uniformity. The concentration dependence of the film thickness at a fixed spin speed allowed identification of the polymer-coil overlap region and enabled estimation of the effective molecular weight of the polymer base, M_eff = (25 ± 7) kg/mol. Lithographic characterization indicated a decrease in sensitivity with increasing electron energy, with a sensitivity of approximately 40 μC/cm² at 25 keV. A depth-dependent dose-distribution model provided an energy-independent average contrast value of γ ≈ 1.67. The results present a coherent and systematic description of ELP-20 behavior under electron-beam exposure and establish a basis for its further use in lithographic processing.