Patent ID: 7718490
Filing Date: 2010-05-18
Classification: H01L

Abstract:
1. A manufacturing method of a nonvolatile semiconductor storage device comprising: forming a first gate insulating film on a semiconductor substrate; depositing a material for floating gate electrodes on the first gate insulating film; forming a plurality of trenches which extend through the material for the floating gate electrodes and the first gate insulating film and reach the semiconductor substrate; etching side walls of the material for the floating gate electrodes to form the floating gate electrodes such that a lower hem of the material for the floating gate electrodes facing an element-forming region is narrower than a width of a surface of the element-forming region in a section taken in a direction perpendicular to a direction in which the trenches extend; forming second gate insulating films on the floating gate electrodes; and forming control gate electrodes on the second gate insulating films.