Nonvolatile semiconductor device and method of manufacturing nonvolatile semiconductor device

Abstract

A semiconductor substrate having a main surface, first and second floating gates formed spaced apart from each other on the main surface of the semiconductor substrate, first and second control gates respectively located on the first and second floating gates, a first insulation film formed on the first control gate, a second insulation film formed on the second control gate to contact the first insulation film, and a gap portion formed at least between the first floating gate and the second floating gate by achieving contact between the first insulation film and the second insulation film are included. With this, a function of a nonvolatile semiconductor device can be ensured and a variation in a threshold voltage of a floating gate can be suppressed.

1 - 11 . (canceled) 
     
     
         12 . A nonvolatile semiconductor device, comprising:
 a semiconductor substrate having a main surface;   first and second floating gates formed on the main surface of said semiconductor substrate;   first and second control gates respectively located on said first and second floating gates;   a porous insulation film filled between said first floating gate and said second floating gate and between said first control gate and said second control gate, said porous insulating film having a permittivity lower than that of a silicon oxide film; and   another insulation film formed on an upper surface of said insulation film and having a moisture-resistant property to prevent water from entering into said porous insulation film.   
     
     
         13 . The nonvolatile semiconductor device according to  claim 12  wherein, the porous insulation film is entirely filled between said first floating gate and said second floating gate.