Low Activation Energy Fullerene Molecular Resist

摘要

Recently there has been significant interest in the field of molecular resists as a route to shrinking the trade-off betweenresolution, line width roughness and sensitivity for next generation lithography. We have previously presented initialresults of a three component fullerene derivative based negative tone chemically amplified electron beam resist withsparse feature resolution of ~12 nm, half pitch resolution of ~20 nm, sub 5 nm line width roughness, sub 10 μC/cm~2sensitivity, and high etch durability. Here we present a further study of the properties of this molecular resist. Thematerial shows extremely wide process latitude. In particular it has been shown that the resolution and sensitivity of theresist are not strongly affected by the post exposure bake conditions. Indeed a post exposure bake was not required at allin order to observe high resolution high sensitivity behavior from the material implying that this is a low activationenergy resist. Such low Ea resists were original developed to address problems with airborne contaminants (T-topping)but can suffer from problems with extended post exposure delay (acid diffusion) and with sensitivity to humidity.However, the fullerene based resist was extremely stable under ambient conditions and for post exposure delays of 24hours, regardless of whether a post exposure bake was applied, showing that the post exposure bake step can beeliminated for this resist, and furthermore that the chemical amplification reaction in the material is in some way selflimiting.