US Patent 7169668 Method of manufacturing a split-gate flash memory device

A method of manufacturing a split-gate flash memory device is disclosed. On a semiconductor substrate having a plurality of parallel conductive lines, a plurality of doped regions are formed by an ion implantation using the conductive lines as mask. Then, the conductive lines are trimmed for thinning the cover area. Afterward, a composite dielectric layer is formed on the substrate and covers the conductive lines. Finally, a plurality of word lines are formed on the composite dielectric layer.