Nanolithography with an acid catalyzed resist

Poly(p-t-butyloxycarbonyloxystyrene) resist shows great potential for electron-beam nanolithography, particularly as a negative resist. The resist has been used to fabricate structures with linewidths as narrow as 18 nm. The resist can be processed in both positive and negative modes depending upon the developing solvent, and linewidths <40 nm have been obtained in both cases. The exposure mechanism is based upon a new resist design principle incorporating an acid catalyst. The sensitivity of the resist can be at least six times higher than that of polymethylmethacrylate (PMMA) exposed under the same conditions (i.e., 50 kV, thin membrane substrates). The exposure distribution for the resist in the negative mode has been determined, confirming its resolution potential. These data indicate that the increase in sensitivity realized through incorporation of a gain mechanism in the resist chemistry is not achieved at a large loss in resolution. In its negative mode, the resist exhibits adequate ion etch resistance for device fabrication. The resist compares favorably with other negative resists for nanolithography with regards to both resolution, and its ability to be cleanly removed by rf plasma oxidation after serving as an ion etch mask.