Fabrication of ultra-high-density nanodot array patterns (∼3 Tbits/in.2) using electron-beam lithography

The authors fabricated 15 nm pitch scale high-density dot patterns on a Si substrate using a hydrogen silsesquioxane electron-beam (e-beam) resist, vacuum treatment as a prebake, and vertical sidewall etching. The e-beam lithography was performed at 100 keV. The dot density fabricated was close to 3 Tbits/in.,2 which is one of the highest density patterns reported thus far. The process window was quite wide and the result can be easily and routinely duplicated.