Non-volatile semiconductor memory device and method for manufacturing the same

A method for manufacturing a non-volatile semiconductor memory device comprising the steps of:

• forming a gate dielectric film on a semiconductor substrate having a first conduction type;
• forming floating gates on the gate dielectric film;
• forming a tunneling dielectric film so as to cover said floating gate;
• forming control gates on the tunneling dielectric film so as to have a region overlapping said floating gates through said tunneling dielectric film;
• forming a first diffused region on a surface of said semiconductor substrate so as to be located between the adjacent floating gates, said diffused region having a second conduction type opposite to the first conduction type;
• after having formed a dielectric film and a silicon nitride film on the entire surface of said semiconductor substrate, anisotropically etching said dielectric film and said silicon nitride film using a photoresist film formed on the floating gate and control gate on the side adjacent to said first diffused region so that said silicon nitride film is patterned and the surface of said semiconductor substrate on a region where a second diffused region is to be formed is exposed;
• forming said second diffused region having the second conduction type on the surface of said semiconductor substrate;
• after having formed an electrode wiring film in contact with said first and second diffused regions, forming a silicon nitride film on the entire surface of said semiconductor substrate inclusive of said electrode wiring film;
• successively stacking a dielectric film and an SOG film on the silicon nitride film and etching-back said SOG film to a form a flattened dielectric film;
• and
• forming a wiring in contact with said diffused region through a hole made in said interlayer dielectric layer.

A method for manufacturing a non-volatile semiconductor memory device comprising the steps of:

• forming a gate dielectric film on a semiconductor substrate having a first conduction type;
• forming a floating gate on the gate dielectric film;
• forming a tunneling dielectric film so as to cover said floating gate;
• forming a control gate on the tunneling dielectric film with a region of said control gate overlapping said floating gate through said tunneling dielectric film;
• forming a diffused region on a surface of said semiconductor substrate adjacent to said floating gate and said control gate, said diffused region having a second conduction type opposite to the first conduction type;
• forming a silicon nitride film on the entire surface of the device formed in the preceding steps;
• and
• forming a SOG film above said silicon nitride film, wherein said silicon nitride layer forms a moisture barrier between said tunneling dielectric film and said SOG film.