Nano-dot arrays with a bit pitch and a track pitch of 25 nm formed by EB writing for 1 Tb/in2 storage

The possibility of forming very fine pits or dots with a bit pitch (BP) and a track pitch (TP) of 25 nm was investigated using a conventional electron-beam (EB) writing system and positive and negative EB resists ZEP520 and calixarene, respectively. In our experiments, we obtained very small dots with a diameter of around 13 nm, and ultrahigh-density dot arrays with a BP and a TP of 25 nm using calixarene resist. Calixarene resist is very suitable for the formation of ultrahigh-packed dot array patterns, and promises to open the way toward 1 trillion bits/in2 storage. We believe that calixarene is more suitable for ultrahigh-density pattern formation than ZEP520 because of its exposure intensity distribution function and its resist structure.