Method of fabricating mask read only memory

Abstract

A method of fabricating a mask read only memory. Gate stacked structures, each of which made up of a gate dielectric layer, a gate conductive layer and a gate cap layer, are formed on a substrate. Source/drain regions are between, but not adjacent to the gate stacked structures. Regions between the source/drain regions and the gate stacked structures are coding areas. A dielectric layer is formed to fill spaces between the gate stacked structures. A photoresist layer with openings exposing the first dielectric layer on the coding areas is formed. The exposed first dielectric layer is removed to form implantation openings of the coding areas. Ion implantation is performed on the exposed coding areas. The photoresist layer is removed, and another dielectric layer is formed to fill the implantation openings. An etching back process is performed to expose the gate conductive layer. A word line is formed on the gate conductive layer.