Method of forming a semiconductor storage device

Abstract

The invention provides a floating gate semiconductor storage device equipped with an erase gate electrode that includes first and second diffusion layers, an isolation insulating film, a gate insulating film, a floating gate electrode, a control gate electrode, a capacitor dielectric film, an erase gate electrode and a tunneling insulating film. In manufacturing the semiconductor storage device, after forming the first and second diffusion layers in a semiconductor substrate, an insulating film for isolation is deposited on the semiconductor substrate. The insulating film for isolation is simultaneously or individually patterned into an isolation insulating film and first and second lower contact holes respectively reaching the first and second diffusion layers. The semiconductor device includes first and second contact members filled in the first and second lower contact holes to be in contact with the first and second diffusion layers. Therefore, in first and second upper contact holes formed in an interlayer insulating film disposed above the contact members so as to respectively reach the first and second contact members, the aspect ratio can be reduced.