Plasma-Polymerized Chlorinated α-Methylstyrene (PP-C-αMS): A High Performance Negative Electron Resist

This paper presents some preliminary results on improvement in the e-beam sensitivity of plasma-polymerized α-methylstyrene (PP-αMS) resist, by chlorination. Electrodeless glow discharge polymer films of α-methylstyrene (PP-αMS) and chlorinated α-methylstyrene (PP-C-αMS) are synthesized by using the standard Ar gas flow reactor under different deposition conditions. Polymer composition and its structure are evaluated using XPS and FTIR techniques. Elemental analysis of the films is carried out for the estimation of chlorine concentration. The evaluation as e-beam resist of PP-αMS and PP-C-αMS is made by electron beam mask fabricator (EBMF 2.5). The sensitivity (D n 0.5) of PP-αMS for 20 kV electrons is 1000 µC/cm2. Addition of ≈4.0% chlorine in the polymerization process increases the sensitivity to 1.0 µC/cm2. Further, the sensitivity of (PP-C-αMS) is found to be a function of chlorine content. This material exhibited a 1 µm-resolution line-and-space pattern.