Polysubstituted derivatives of triphenylene as high resolution electron beam resists for nanolithography

Abstract

We have explored the application of polysubstituted derivatives of triphenylene as high resolution, high etch durability electron beam resists. Room temperature spin coating was used to produce films of the derivatives on silicon substrates. Exposure to a 20 keV electron beam was found to alter the dissolution rate of these derivatives in various organic solvents. Doses of between ∼3×10−4 and ∼2.5×10−3 C/cm2 substantially increased the solubility of the derivative hexapentyloxytriphenylene in polar solvents (positive tone behavior). Doses greater than ∼2.5×10−3 C/cm2 led to a decrease in solubility in both polar and nonpolar solvents (negative tone behavior). Other derivatives also demonstrated a reduction in their dissolution rate for doses between ∼1.5×10−3 and ∼6.5×10−3 C/cm2. The etch durabilities of the positive and negative tone patterns were found to be, respectively, ∼25% less and ∼70% greater than that of a conventional novolac based negative tone resist. Line and space patterns were defined in one of the resists with a resolution of ∼14 nm and structures with an aspect ratio of ∼50–1 were etched into silicon.