Flash memory device and manufacturing method thereof

Abstract

A method of manufacturing a flash memory device is provided. Multiple stack structures each comprising a tunneling oxide layer and a first conductive layer are formed over a substrate. Thereafter, multiple embedded doping regions is formed in the substrate between the stack structures. A dielectric layer is formed over the substrate to cover the stack structures and then the dielectric layer is etched back and a portion of dielectric layer is remained on the stack structures. Using a portion of the remaining dielectric layer as a mask, a portion of the first conductive layer is removed. An inter-layer dielectric layer and a second conductive layer are sequentially formed over the first conductive layer. Because a self-aligned process is used to define the floating gate and the floating gate has a narrow-top/wide-bottom configuration, the fabrication process is simplified and the coupling ratio of the stack gate is increased.

Dependencies are inferred from the claim text.