A novel water developable tetraphenyltin-based nonchemically-amplified molecular resist for sub-13 nm lithography

Abstract

A single-component nonchemically-amplified resist (n-CAR) based on a tetraphenyltin derivative (SnMSF₄) was developed for electron beam and extreme ultraviolet lithography. The structure of SnMSF₄ was characterized by ¹H NMR, ¹⁹F NMR, HRMS, FTIR spectroscopy, and elemental analysis. SnMSF₄ exhibits good thermal stability, and its non-planar structure makes it have good film-forming performance, which makes it suitable for resist materials. SnMSF₄ can be used as a negative resist developed with water (H₂O), mixtures of ethanol (EtOH) and H₂O (V_EtOH : V_H2O = 1 : 10–20), or mixtures of isopropyl alcohol (IPA) and H₂O (V_IPA : V_H2O = 1 : 10–20). Electron beam lithography (EBL) studies revealed that 20 nm features were successfully patterned using the SnMSF₄ resist. Moreover, the study of extreme ultraviolet lithography (EUVL) performance shows that 13 nm line/space (L/S) patterns were successfully patterned at a dose of 163 mJ cm⁻² with a line edge roughness (LER) of 3.3 nm. Further studies on the underlying mechanisms showed that the solubility change of the SnMSF₄ resist depends on the decomposition of the sulfonium group. This research will provide useful guidance for the research of high-resolution electron beam and EUV resist materials.