Negative tone chemically amplified resist formulation optimizations for ultra high-resolution lithography

Starting from the Sumitomo commercial platform NEB-33 resist, three new experimental negative tone chemical amplified resist (CAR) formulations have been developed, to push resolution below 40 nm in direct electron beam lithography. PEB temperatures and times have been optimized between 60 and 100 degreesC and, respectively, 20 and 120 s. Fourier transform infra red spectra have been performed and allowed us to follow the solvent and PAG concentration in order to optimize processes on all samples. As a consequence, 25-nm isolated lines have been resolved with these new chemical amplified resists. (C) 2003 Elsevier Science B.V. All rights reserved.