Abstract: The present invention provides a manufacturing method for a semiconductor storage device, in which data are written by implanting impurity ions onto a channel area of a memory cell transistor, which comprises the steps of: a step for forming a gate electrode using a high melting point metal over the surface of a semiconductor substrate, and for forming an oxide film on the surface of the gate electrode; a step for forming a film on the area for forming a data confirmation pattern; and a step for forming the data confirmation pattern on the film in performing etching in the film at a high selection ratio for the above-mentioned oxide film with a mask to be used for ion implantation for ROM data.