70nm NAND flash technology with 0.025 /spl mu/m/sup 2/ cell size for 4Gb flash memory

A 4 Gb NAND flash memory with a 70 nm design rule is developed for mass storage applications. The cell size is 0.025 /spl mu/m/sup 2/, which is the smallest value ever reported. For the integration, an ArF lithography process along with resolution enhancing techniques was utilized, and poly-Si/W gate technology with an optimized re-oxidation process was implemented.