A New High Resolution Negative Electron Resist Chloromethylated Poly-α-Methylstyrene (αM-CMS)

A new negative electron resist chloromethylated poly-α-methylstyrene (αM-CMS) was synthesized from nearly monodisperse poly-α-methylstyrene. αM-CMS has the highest contrast (γ=2.5–3.0) among the known negative polymer resists and has high sensitivity (3–33 µC/cm2). Sufficient resolution for a 1 µm pattern fabrication process was demonstrated. Submicron patterns as small as 0.1 µm were obtained in 0.4 µm thick αM-CMS on a solid substrate, suggesting that the ultimate resolution of the resist is better than 0.1 µm. Excellent thermal stability and high dry-etching durability assure wide application of αM-CMS in electron beam lithography.