High aspect ratio micro/nano machining with proton beam writing on aqueous developable - easily stripped negative chemically-amplified resists

Proton beam writing (PBW) is a new direct-writing process that uses a focused beam of MeV protons to pattern resist material at nano dimensions. PBW has the unique ability to maintain a straight path through 50 μm thick resist films, and is suitable for high aspect ratio micro(nano)-machining. TADEP resist is a new promising high aspect ratio chemically-amplified resist that can be developed in aqueous base developer and has the capability of stripping in conventional stripping schemes. By employing PBW on TADEP resist patterns with 280 nm linewidth and a thickness of 12 μm have been resolved showing an aspect ratio of 42. Following Ni electroplating of the TADEP features, Ni structures of height 0.8 μm and spacing of 167 nm, produced in 2 μm thick TADEP, were demonstrated indicating the easy stripping characteristics of the TADEP resist.