Nonvolatile Semiconductor Memory Device Having Multi-Layered Oxide/(OXY) Nitride Film as Inter-Electrode Insulating Film and Manufacturing Method Thereof

摘要

A nonvolatile semiconductor memory device includes a first insulator, first conductor, element isolation insulator, second insulator and second conductor. The first insulator is formed on the main surface of a substrate and the first conductor is formed on the first insulator. The element isolation insulator is filled into at least part of both side surfaces of the first insulator in a gate width direction thereof and both side surfaces of the first conductor in a gate width direction thereof and is so formed that the upper surface thereof will be set with height between those of the upper and bottom surfaces of the first conductor. The second insulator includes a three-layered insulating film formed of a silicon oxide film, a silicon oxynitride film and a silicon oxide film formed on the first conductor and element isolation insulator. The second conductor is formed on the second insulator.