NONVOLATILE SEMICONDUCTOR STORAGE DEVICE

1 . A nonvolatile semiconductor storage device comprising:

a floating gate provided above a substrate with a gate insulating film being provided between said floating gate and said substrate;

a control gate provided above said substrate such that said control gate is arranged adjacent to said floating gate with a tunnel insulating film being provided between said control gate and said floating gate; and

a side wall insulating film,

wherein said control gate includes:

a first side surface on a side near said floating gate;

a second side surface opposite to said first side surface;

a silicide region formed in an upper portion of said control gate above said first side surface; and

a protruding portion formed in an upper portion of said control gate above said second side surface, and

said side wall insulating film includes:

a first portion which covers at least a portion of said protruding portion without covering said silicide region; and

a second portion which is provided continuously from said first portion and covers said second side surface with contacting said second side surface.

2 . The nonvolatile semiconductor storage device according to claim 1 , wherein said protruding portion includes:

a first region formed as a side surface on a side near said floating gate; and

a second region opposite to said first region and formed as a surface continued from said second side surface,

said first portion of said side wall insulating film covers said first region, and

said second portion of said side wall insulating film covers said second region and said second side surface.

3 . The nonvolatile semiconductor storage device according to claim 2 , wherein a cross-section of said protruding portion includes:

a first edge corresponding to said first region;

a second edge corresponding to said second region; and

an apex between said first edge and said second age,

said cross-section is included in a cutting plane perpendicular to said substrate and said first side surface, and

said side wall insulating film covers said apex.

4 . The nonvolatile semiconductor storage device according to claim 3 , said side wall insulating film includes a first end corresponding to a position at which a surface of said first portion intersects a upper surface of said control gate, and

said silicide region is provided on said upper surface from said first end to said first side surface.

5 . The nonvolatile semiconductor storage device according to claim 4 , said side wall insulating film includes a second end corresponding to a position at which a surface of said second portion intersects a surface of said substrate, and

said side wall insulating film is formed from said first end to said second end with covering said first edge and said second edge.

6 . A manufacturing method of a nonvolatile semiconductor storage device comprising:

forming on a substrate, a gate insulating film and a conductive film for floating gate in a order of said gate insulating film and said conductive film of floating gate;

forming spacer insulating films each having a side wall shape on said conductive film for floating gate such that said spacer insulating films face to each other;

removing said conductive film for floating gate and said gate insulating film in a region between said spacer insulating films by using said spacer insulating films as masks;

forming a first diffusion layer in a surface portion of said substrate in said region between said spacer insulating films;

burying a space between said spacer insulating film with conductive material after said forming said first diffusion layer;

forming a floating gate by selectively removing said conductive film for floating gate outside said spacer insulating films with said spacer insulating films being used as masks;

forming a tunnel insulating film which covers said floating gate, said spacer insulating films and said conductive material;

forming a conductive film for control gate on said tunnel insulating film;

forming a first insulating film which covers said conductive film for control gate;

removing a portion of said first insulating film above said floating gate, said spacer insulating films and said conductive material such that a surface of said conductive film for control gate is partially exposed;

forming a protruding portion in said conductive film for control gate by etching said conductive film for control gate such that said conductive film for control gate remains at a border between said conductive film for control gate and said first insulating film;

removing said first insulating film;

etching-back said conductive film for control gate to form a control gate after said removing said first insulating film while keeping a shape of said protruding portion;

selectively removing said tunnel insulating film;

covering said control gate with a second insulating film such that said protruding portion is covered with said second insulating film after said selectively removing said tunnel insulating film; and

etching-back said second insulating film to form a side wall insulating film which covers a side surface of said control gate and said protruding portion.

7 . The manufacturing method of a nonvolatile semiconductor storage device according to claim 6 , further comprising:

implanting impurities into a region of said substrate arranged outside said spacer insulating films to form a second diffusion layer, and

forming silicide on a surface of said conductive material between said spacer insulating films, a surface of said control gate and a surface of said second diffusion layer.

8 . The manufacturing method of a nonvolatile semiconductor storage device according to claim 6 , wherein said forming said protruding portion includes performing a slope etching to form a slope in said border between said conductive film for control gate and said first insulating film, and

said performing said slope etching includes forming an apex of said protruding portion to be acute-angled.

9 . The manufacturing method of a nonvolatile semiconductor storage device according to claim 6 , wherein said etching-back said conductive film for control gate includes forming a valley in an upper portion of said control gate by etching-back said conductive film for control gate.