DEVELOPMENT OF AN ELECTRON-BEAM PROCESS FOR THE FABRICATION OF X-RAY NANOMASKS

We report on the development of an e-beam lithography process for the fabrication of x-ray masks for nanolithography with minimum feature si ze down to 65 nm. The process is based on accelerating voltages below 50 kV, with a single layer of 0.55 mum thick PMMA. Particular emphasis is addressed to the study and the control of the various variables af fecting the ultimate practical resolution, i.e., the developer concent ration, the accelerating voltage, the exposure latitude, the reproduci bility of the results and the effect of the beam diameter. Monte Carlo simulation was used to separate the effect of forward- and backscatte ring. Dense and reproducible 65 nm-resolution arrays of gold electropl ated lines have been achieved at 50 kV on silicon nitride membranes. S ome of the fabricated nanomasks have been successfully replicated by s ynchrotron radiation lithography.