Chemically amplified molecular resists for electron beam lithography

Molecular resists, such as fullerene and triphenylene derivatives, use small carbon rich molecules, which give the potential for greater
resolution, lower line edge roughness and higher etch durability than traditional polymeric materials. Their main limitation has been low
sensitivity to irradiation. Here the chemical amplification of fullerene and triphenylene negative tone molecular resists is demonstrated.
The sensitivity of a fullerene resist to 20 keV electrons was improved from 550 to 8 lC/cm2 by addition of an epoxide crosslinker and
photoinitiator. Lines of width 25 nm were written using 30 keV electrons. A triphenylene with pendant epoxy groups was also studied. In
this case the sensitivity reached on addition of photoinitiator was 7.5 lC/cm2 at 20 keV and lines of width 40 nm have been achieved at
30 keV.