Patent ID: 6403421
Filing Date: 2002-06-11
Classification: H01L

Abstract:
A method of producing a semiconductor nonvolatile memory device comprising the steps of:forming a gate insulating film on a semiconductor substrate having a channel formation region; forming a first floating gate at an upper layer of the gate insulating film; forming a mask layer at an upper layer of the first floating gate; forming an element isolation trench in the semiconductor substrate in a region sandwiched between first floating gates; forming an element isolation insulating film by burying an insulator in the element isolation trench; forming a second floating gate layer over an entire surface including an upper layer of the mask layer; removing the second floating gate layer, leaving parts thereof as floating gates covering facing sides of the mask layer and the first floating gate, and further directly contacting and covering an exposed surface of the element isolation insulating film; removing the mask layer; forming an inter-layer insulating film on the first floating gate and the second floating gates; forming a control gate at an upper layer of the inter-layer insulating film; and forming a source-drain region connected to the channel formation region.