Method for fabricating a self-aligned source line flash memory device

Abstract

A method for fabricating a flash memory device having a self-aligned source includes providing a semiconductor substrate having a source region separated from a drain region by a channel region. The method also includes forming an isolation structure in the semiconductor substrate that crosses the source, drain, and channel regions of the semiconductor substrate. The method also includes forming a continuous stack structure outwardly from the channel region of the semiconductor substrate and the isolation structure. The method includes depositing a bottom anti-reflective layer over the semiconductor substrate, the isolation structure and the stack structure to substantially uniformly planarize the semiconductor substrate and the isolation structure. The method further includes depositing a photoresist layer over select portions of the bottom anti-reflective layer and the continuous stack structure to form a self-aligned source pattern using a photo mask. The method includes etching the isolation structure and the bottom anti-reflective layer corresponding to the self aligned source pattern using a low selectivity etch process to remove a portion of the isolation structure and etching a remaining portion of the isolation structure using high selectivity etch process.