The invention discloses a process method for manufacturing a
flash memory device, which comprises the following steps of: forming a
coupling oxide layer with the thickness of 50 angstroms to 150 angstroms on a substrate; forming a floating gate
polycrystalline silicon layer on the
coupling oxide layer, wherein the floating gate
polycrystalline silicon layer is used for preparing a floating gate of the
flash memory; forming a
protective oxide layer on the floating gate
polycrystalline silicon layer, wherein the
protective oxide layer is used for protecting the floating gate polycrystalline
silicon layer in a subsequent wet
etching process; forming a
nitride layer on the
protective oxide layer; and removing the
nitride layer through a wet
etching process. In the manufacturing process of the
flash memory device, after the floating gate polycrystalline
silicon layer is formed, the protective
oxide layer is formed on the floating gate polycrystalline
silicon, so that the floating gate polycrystalline silicon layer can be protected in the subsequent wet
etching process, the floating gate polycrystalline silicon layer is prevented from generating defects and being damaged, the uniformity of the floating gate polycrystalline silicon layer is improved, and the yield of the flash memory device is improved. The
coupling of the word line and the control gate to the floating gate of the device is improved, and the leakage current phenomenon of the device is improved.