Nonvolatile semiconductor memory and fabricating method thereof

A method of fabricating a nonvolatile semiconductor memory, comprising:

• a word line forming step of forming plural word lines, each having an insulating layer of a first insulating material as a top layer, in parallel on a semiconductor substrate surface of a semiconductor substrate, in which field areas are formed;
• a doping step of doping impurity into the semiconductor substrate after the word line forming step in order to create source regions and drain regions and source lines at areas except for the field areas;
• a side wall forming step of forming side walls of second insulating materials on side surfaces toward the drain regions of the plural word lines;
• an etching stopping layer forming step of forming an etching stopping layer on an entire surface of the semiconductor substrate after the side wall forming step, wherein said etching stopping layer forming step includes forming the etching stopping layer of a conducting material consisting of etching stopping parts, each of the etching stopping parts covering one drain region;
• an intermediate insulating layer forming step of forming an intermediate insulating layer of a third insulating material, which is different from the material used for the etching stopping layer, on the etching stopping layer;
• a resist pattern forming step of forming a resist pattern having openings in areas corresponding to the drain regions, on the intermediate insulating layer;
• a drain contact hole forming step of forming drain contact holes by etching the intermediate insulating layer using the resist pattern as a mask;
• and
• a bit line forming step of forming bit lines by depositing a conducting material on the intermediate insulating layer in which drain contact holes are formed, and patterning the deposited conducting material.

A method of fabricating a nonvolatile semiconductor memory, comprising:

• forming plural word lines, each having an insulating layer of a first insulating material as a top layer, in parallel on a semiconductor substrate surface of a semiconductor substrate, in which field areas are formed;
• doping impurity into the semiconductor substrate after the forming plural word lines, in order to create source and drain regions and source lines at areas except the field areas;
• forming side walls of second insulating materials on side surfaces toward the drain regions of the plural word lines;
• forming an etching stopping layer on an entire surface of the semiconductor substrate after the forming side walls, said forming an etching stopping layer including forming an etching stopping layer having openings in areas except areas in which the drain regions are formed;
• and
• forming an intermediate insulating layer of a third insulating material, which is different from the material used for the etching stopping layer, on the etching stopping layer.

A method of fabricating a nonvolatile semiconductor memory, comprising:

• forming plural word lines, each having an insulating layer of a first insulating material as a top layer, in parallel on a semiconductor substrate surface of a semiconductor substrate, in which field areas are formed;
• doping impurity into the semiconductor substrate after the forming plural word lines, in order to create source and drain regions and source lines at areas except the field areas;
• forming side walls of second insulating materials on side surfaces toward the drain regions of the plural word lines;
• forming an etching stopping layer on an entire surface of the semiconductor substrate after the forming side walls, wherein forming an etching stopping layer includes forming the etching stopping layer of a conductive material, the etching stopping layer consisting of etching stopping parts, each of the etching stopping parts covering one drain region;
• and
• forming an intermediate insulating layer of a third insulating material, which is different from the material used for the etching stopping layer, on the etching stopping layer.