Charge trap flash (CTF) memory is one of the most promising technologies for the next generation NAND technology. Among various CTF memories, excellent manufacturability of TaN-Al2O3-Si3N4-SiO2-Si (TANOS) structure has been successfully developed by achieving 32Gb MLC NAND flash using 40nm technology node (Y. Park et al., 2006). 3 dimensional NAND cells such as hemispherical corner (HC) (D. Kwak et al., 2007) and FinFET TANOS (S. Lee et al., 2006) devices with suppressed short-channel effects and improved data retention characteristic were also proposed as cell structures for the next generation beyond 40nm technology node. However, understanding of other device characteristics such as disturb characteristics of the structures is still insufficient. In this paper, various device characteristics of rounded corner (RC) TANOS including disturb and data retention characteristics are investigated and compared with the conventional planar TANOS. Finally, the rendering of RC TANOS for improving disturb characteristics was proposed.