| 摘要 |
PURPOSE: To provide a method for manufacturing a mask ROM where the gap between word lines is small and a process margin can be fully secured so that the mask ROM can be highly integrated easily. CONSTITUTION: A first insulating film 106, that becomes a protection film on ion implantation for programming, is formed at the upper part of a semiconductor substrate where a gate oxide film 102 and a first conductive layer 104 are formed. Then, after a pattern has been formed at the first insulating film with a gap of one word line to be formed, a second insulating film 112 with a different property from that of the first insulating film is formed on the entire substrate surface with a thickness of sub-microns. After that, a photoresist is applied to the upper surface of the substrate and is etched, until the second insulation film on the upper surface of the first insulating film can be exposed. Then, the exposed second insulating film is eliminated, thus eliminating the first conductive layer, only at the exposed part and forming a word line. Further, the first and second insulating films, formed alternately on the word line, are selectively eliminated by a separate etching process. |
