The present invention provides a method for manufacturing a
flash memory device. A gate structure is formed on a substrate, and a tunneling
oxide layer and a word line are formed on both sides of the gate structure. The tunneling
oxide layer covers the substrate, and the word line covers the sidewalls of the gate structure and a part of the top surface of the tunneling
oxide layer; the exposed part of the tunneling oxide layer is thinned; a first sidewall is formed to cover a part of the sidewalls of the word line and a part of the top surface of the tunneling oxide layer, and a recess is formed at the surface of the word line not covered by the first sidewall; a self-aligned
silicide blocking layer with an opening is formed to
expose at least the gate structure, the word line, and the first sidewall. By
thinning the thickness of the tunneling oxide layer, the present invention reduces or avoids damage to the tunneling oxide layer during subsequent
etching processes. By controlling the
etching process time of the self-aligned
silicide blocking layer, the residual oxide in the recess is reduced or avoided, ensuring the formation of a good
metal silicide layer in the subsequent process, reducing the
contact resistance of the
flash memory device, and improving the performance and stability of the
flash memory device.