US Patent 7642595 Nonvolatile semiconductor memory and method of fabrication thereof

There are provided a nonvolatile semiconductor memory of a structure in which electric signals from peripheral circuits are reliably transferred to control gates via word lines even if contact holes cannot be opened accurately above the word lines, and a method of fabricating the nonvolatile semiconductor memory. Plural word lines and plural bit lines are disposed on a semiconductor substrate, and there are memory cells at intersecting portions of the word lines and the bit lines. At contact portions of the word lines and metal wires of an upper layer, polysilicon regions, which include the contact portions, are formed beneath a polysilicon forming the word lines, as an etching stop layer at a time of forming contacts.