Fullerene Resist Materials for the 32 nm Node and Beyond

• Published in: Advanced functional materials 2008-07, Vol.18 (13), p.1977-1982
• Main Authors: Gibbons, Francis P., Robinson, Alex P. G., Palmer, Richard E., Diegoli, Sara, Manickam, Mayandithevar, Preece, Jon A.
• Format: Article
• Language: English
• Subjects: chemical amplification; electron beam lithography; fullerene; molecular resists
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.200701155

Current resist materials cannot simultaneously meet the sensitivity, resolution and line width roughness (LWR) requirements set out by the International Technology Roadmap for Semiconductors (ITRS) for the 32nm node and beyond. Here we present a fullerene‐based, chemically amplified resist system, which demonstrates the potential to fulfill these requirements for next generation lithography. A chemically amplified fullerene resist was prepared, consisting of the derivative MF07‐01, an epoxide crosslinker, and a photoacid generator, such as triarylsulfonium hexafluoroantimonate. The sensitivity of this resist was shown to be between 5 and 10 µC cm−2 at 20 keV for various combinations of post‐application bake and post‐exposure bake conditions. Using 30 keV electron beam exposure, sparse patterns with 15 nm resolution were demonstrated, whilst for dense patterns a half‐pitch of 25 nm could be achieved. The LWR for the densely patterned features is ∼4 nm. The etch durability of the fullerene CA system was shown to be comparable to that of SAL601, a common novolac‐based commercial resist, at almost four times that of silicon. Molecular resists promise a route for lithographic performance improvement over polymeric resists. Typically, molecular resists show high resolution but low sensitivity. We report a high sensitivity chemically amplified fullerene resist capable of 25 nm dense and 15 nm sparse resolution.