Chemical Amplification of a Triphenylene Molecular Electron Beam Resist


  • The authors would like to thank Rohm and Haas (Electronic Materials) (USA), for their financial support of the research and acknowledge useful discussions with K. O'Connell, R. Brainard, T. Zampini, and J. Mackevich. The authors would like to acknowledge the assistance of Dr. G. P. Patsis in measuring line width roughnesses. H. M. Z. would like to thank the Universiti Teknologi Petronas, Malaysia, for sponsoring her studies.


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 ∼ 6 × 10–4 C cm–2, which increased substantially to ∼ 1.5 × 10–5 C cm–2 after chemical amplification (CA) using a cationic photoinitiator. This was further improved, by the addition of a second triphenylene derivative, to ∼ 7 × 10–6 C cm–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.