Chemical Amplification of a Triphenylene Molecular Electron Beam Resist

Molecular resists, such as triphenylene derivatives, are small carbon rich molecules, and thus give the potential for higher lithographic
resolution and etch durability, and lower line width roughness than traditional polymeric compounds. Their main limitation
to date has been poor sensitivity. A new triphenylene derivative molecular resist, with pendant epoxy groups to aid
chemically amplified crosslinking, was synthesized and characterized. The sensitivity of the negative tone, pure triphenylene derivative
when exposed to an electron beam with energy 20 keV was ~610–4 Ccm–2, which increased substantially to
~ 1.5 10–5 Ccm–2 after chemical amplification (CA) using a cationic photoinitiator. This was further improved, by the addition
of a second triphenylene derivative, to ~710–6 Ccm–2. The chemically amplified resist demonstrated a high etch durability
comparable with the novolac resist SAL 601. Patterns with a minimum feature size of ~ 40 nm were realized in the resist with a
30 keV electron beam