JPS647569A - Manufacture of semiconductor nonvolatile memory - Google Patents

Abstract

PURPOSE:To dispense with a photoresist film for ion implantation so as to simplify a process by a method wherein a drain source region is formed through ion implantaion in such a state that a first polycrystalline silicon layer is left unremoved on a drain forming region. CONSTITUTION:A field insulating film 2 used for the element separation is selectively provided on the primary face of a P-type silicon substrate 1 so as to divide an element forming region, of which surface a gate insulating film 3 is formed on. Next, a polycrystalline silicon layer is deposited on the whole surface and subjected to etching for forming a mask 4 selectively on a floating gate electrode and a drain forming region. Then, a silicon oxide film 5 is formed on the surface of the mask 4, a polycrystalline silicon layer 6 is deposited on the whole surface, and a photoresist film 7 with a gate electrode forming pattern is selectively formed on the polycrystalline silicon layer 6 of the element forming region. Moreover, the polycrystalline silicon layer 6 is etched through the photoresist film 7 used as a mask for the formation of a control gate electrode 8, and a deep and a shallow drain regions 9 and 10 are formed by impalanting N-type impurity ions using the photoresist film 7 and the field insulating film 2 as masks.