Method for manufacturing semiconductor device

A method for manufacturing a semiconductor device, comprising:

• defining a plurality of element forming areas, an element isolation structural portion forming area which separates the respective adjacent element forming areas from each other;
• forming an element isolation structural portion in the element isolation structural portion forming area;
• depositing a gate oxide film which covers the upper surface of the substrate and the element isolation structural portion;
• depositing a floating gate film over the gate oxide film;
• depositing a spacer film over the floating gate film;
• forming an etching resistant mask pattern covering the floating gate film over the spacer film;
• performing isotropic etching using the etching resistant mask pattern as a mask to remove the spacer film in an area wider than an area exposed from the etching resistant mask pattern, extending from an end edge portion of the etching resistant mask pattern to a side below the etching resistant mask pattern, thereby forming a spacer film pattern having an end edge exposed portion;
• performing anisotropic etching using the etching resistant mask pattern as a mask to remove the floating gate film thereby to form a floating gate pattern, the floating gate pattern having an exposed end portion including an obtuse angle with an exposed end surface of the floating gate pattern;
• removing the etching resistant mask pattern and the spacer film pattern;
• forming a second gate oxide film which covers the floating gate pattern;
• depositing a control gate film over the second gate oxide film;
• and
• patterning the control gate film to form a control gate pattern.