METHOD FOR MANUFACTURING A NONVOLATILE MEMORY DEVICE

摘要

A manufacturing method of a non-volatile memory device is provided to maintain the height of the element isolation film protruding from the surface of substrate towards the top of substrate constantly. A manufacturing method of a non-volatile memory device comprises a step for successively forming a tunneling insulating layer, a first conductive film and a hard mask on the top of the substrate; a step for forming a trench; a step for forming an element isolation film which covers the hard mask by filling the trench; a step for polishing the element isolation film; and a step for forming a second conductive film(208). The hard mask is formed with the nitride film and the laminated oxide film which are successively laminated.