Novel electron beam resist material using hydrophilic protecting group

We discuss a new EB resist material that has an alicyclic (bulky) acetal protecting group, with a hydrophilic group in its chemical structure. We synthesized it by acid catalyzed reaction of poly(hydroxystyrene, PHS) with hyper lactonyl adamantyl vinyl ether (HPVE). AFM analysis showed that the resist composed of HPVE polymer exhibits a uniform dissolution property. And the etching durability was double that of poly(methyl methacrylate) and better than that of ethoxy ethyl-protected PHS. EB resist composed of this material provides 60 nm-L/S patterns at less than 8 μC/cm2 with a 50 kV EB exposure system.