NONVOLATILE MEMORY HAVING UNIFORM CELL ERASE CHARACTERISTICS AND MANUFACTURING METHOD THEREOF

摘要

PURPOSE: A nonvolatile memory and a manufacturing method thereof are provided to obtain uniform erase characteristics of cells in the nonvolatile memory. CONSTITUTION: A first insulating film(COX) is formed on a first substrate(1) of a first conductive type. A first conductive film(PS1), an etching stopper film(LTO), and a spacer film are sequentially accumulated in turn. An opening(2) is formed by selectively removing the spacer film by etching to the etching stopper film. The etching stopper film is removed and a bowl-shaped recess(3) is formed within the opening. A side wall insulating film is formed on the side face of the opening. The first conductive film and the first insulating film are removed. Dopants of a second conductive type are implemented on the substrate within the opening, thereby forming a source or drain. A second insulating film covers the exposed face of the first conductive film. A plug is formed by filling the inside of the opening with a conductive film. The spacer film is removed. A floating gate is formed by selective etching. A control gate is formed on the side of the plug. The other of the source and drain is formed by selectively implanting dopants on the semiconductor substrate.