Fullerene (C60) and its Derivatives as Resists for Electron Beam Lithography

Abstract

The application of fullerene as a negative resist was first studied by Tada and Kanayama who verified that this material could be used as a negative electron beam resist. Its small molecule enables the resist to have a resolution of at least 20 nm. Robinson et al. demonstrated that chemical modification of C60 by adding functional groups to the C60 cage can significantly enhance the resist properties. Chemical amplification of the fullerene derivatives improves their sensitivities while maintaining their high resolution. In this chapter, the concepts of lithography and lithography techniques which include electron beam lithography technology systems are described. Current electron beam resists and their characteristics are discussed. A review of the application of fullerene and its derivatives as electron beam resists is presented. Finally, concepts of chemical amplification and current chemically amplified resists are discussed.Device density of modern computer components has grown exponentially as predicted by Moore’s Law [1] with a decrease in components sizes. Smaller devices mean a reduced interconnect length, reducing the distance electrons have to travel and thus signal delay. Although photolithography has been the technique of choice for the fabrication of microdevices for many years, electron beam lithography is a very promising lithographic technique for nanoscale patterning due to its flexibility and nearly unlimited resolution capability, able to fabricate sub-50 nm features. A factor that influences its resolution is the electron beam resists. The application of fullerene as a negative resist was first studied by Tada and Kanayama [2] who verified that this material could be used as a negative electron beam resist. Its small molecule enables the resist to have a resolution of at least 20 nm. Robinson et al. [3, 4, 5] demonstrated that chemical modification of C60 by adding functional groups to the C60 cage can significantly enhance the resist properties. Chemical amplification of the fullerene derivatives improves their sensitivities while maintaining their high resolution [6, 7]. In this chapter, the concepts of lithography and lithography techniques which include electron beam lithography technology systems are described. Current electron beam resists and their characteristics are discussed. A review of the application of fullerene and its derivatives as electron beam resists is presented. Finally, concepts of chemical amplification and current chemically amplified resists are discussed.