Non-volatile semiconductor memory device and manufacturing method thereof

A manufacturing method of a non-volatile semiconductor memory device, wherein

• the non-volatile semiconductor memory device includes a memory cell array invlufing NAND cell units arranged therein, the NAND cell unit being configured to extend in a first direction vertical to a surface of a semiconductor substrate, the NAND cell unit including a plurality of memory cells and selection transistors connected in series, wherein
• the method comprises:
• forming a first trench on the semiconductor substrate and implanting a sacrifice film in the first trench;
• forming a laminated body where a plurality of conductive films are laminated sandwiching an interlayer insulating film on the semiconductor substrate, the conductive film being control gate lines of the memory cells or selection gate lines of the selection transistors;
• forming a second trench that passes through the laminated body and reaches the sacrifice film and then removing the sacrifice film;
• forming an electric charge accumulating layer and a first silicon film along sidewalls of the first trench and the second trench;
• forming a third trench that reaches the first trench and then further forming a second silicon film inside the first trench through the third trench;
• forming a fourth trench that reaches the first trench and then forming a metal film in the first trench through the fourth trench;
• and
• forming a silicide layer by causing a reaction between the second silicon film and the metal film.