Method of manufacturing a semiconductor device

摘要

The present invention provides a technology which allows the improvement of the capacitor capacitance per unit area, and a technology which allows the simplification of a manufacturing process associated therewith. At least not less than one capacitor formation trench causing the uneven surface is formed on the surface of a capacitor formation region. As a result, the surface area of a capacitor is increased, which enables the improvement of the capacitance of the capacitor per unit area. Further, by forming the capacitor formation trench and an element formation trench formed in the surface of the semiconductor substrate are formed by the same step. As a result, it is possible to simplify the manufacturing process. Whereas, a dielectric film of the capacitor in the capacitor formation region and a high-voltage gate insulating film in a MISFET formation region are formed by the same step. Alternatively, the dielectric film 16a of the capacitor in the capacitor formation region and a memory gate interlayer film between a polysilicon layer and a polysilicon layer in the memory cell formation region are formed by the same step.