Effects of salty-developer temperature on electron-beam-exposed hydrogen silsesquioxane resist for ultradense pattern transfer

The characteristics of salty developers, TMAH/NaCl and NaOH/NaCl, on the processing of hydrogen silsesquioxane (HSQ) resist at elevated temperatures were investigated. The TMAH/NaCl developer demonstrated better contrast than the NaOH/NaCl developer at the temperatures (20-35 degrees C) investigated for both the unbaked and prebaked HSQ resists. The higher contrast developer was utilized to investigate the fabrication of ultradense gratings. Better reproducibility of the gratings was obtained from prebaked HSQ resist even though unbaked HSQ exhibited higher contrast. The ultradense grating patterns realized in HSQ resist was successfully transferred into a Si substrate. By employing the TMAH/NaCl development process at an elevated temperature and the inductively coupled plasma reactive ion etching process, 20-nm-pitch silicon nanowire arrays were demonstrated. (C) 2010 American Vacuum Society. [DOI: 10.1116/1.3504497]