Semiconductor non-volatile memory having semiconductor non-volatile memory cell with electric charge accumulation layer, and method of producing the same

A method of producing a semiconductor non-volatile memory, comprising the steps of:

• defining a memory cell region, a peripheral region, and a dummy region as an intermediate region between the memory cell region and the peripheral region on a surface of a Si (Silicon) layer containing substrate;
• forming a first activation region having a ridge shape and a precursor first element separation region formed of a first embedded insulation film embedded in both sides of the first activation region in the memory cell region in a stripe pattern, respectively
• forming a dummy activation region having a ridge shape in the dummy region in a stripe pattern;
• forming a second activation region having a ridge shape and a second element separation region formed of a second embedded insulation film embedded in both sides of the second activation region in the peripheral region in a stripe pattern, respectively;
• etching the precursor first element separation region from a surface thereof to a middle of a thickness thereof to form a first element separation region
• forming an upper edge portion of the first activation region to protrude as a ridge portion;
• depositing sequentially a gate insulation film and a gate electrode material for covering exposed surfaces of the memory cell region, the dummy region, and the peripheral region from above;
• flattening a surface of the gate electrode material to form a gate electrode layer;
• patterning portions of the gate insulation film and the gate electrode layer in the peripheral region and the dummy region adjacent to the peripheral region to form a second gate insulation film having a flat shape and a second gate electrode extending perpendicularly to a longitudinal direction of the second activation region and covering at least a part of the second activation region, the second element separation region, and the dummy activation region;
• patterning remaining portions of the gate insulation film and the gate electrode layer in the memory cell region and a remaining area of the dummy region to form a first gate insulation film and a first gate electrode extending perpendicularly to a longitudinal direction of the ridge portion and covering over the ridge portion and at least a part of both side surfaces of the ridge portion, the first element separation region, and the dummy activation region;
• defining a first channel forming region in a surface layer region of the ridge portion at a position facing the first gate electrode;
• defining a second channel forming region in a surface layer region of the second activation region at a position facing the second gate electrode;
• diffusing a first impurity in the first activation region on both sides of the first channel forming region in the longitudinal direction to form a first extension region;
• diffusing a second impurity in the second activation region on the both sides of the second channel forming region in the longitudinal direction to form a second extension region;
• depositing sequentially a precursor electric charge accumulation layer and a sidewall insulation film for covering upper surfaces of the memory cell region, the dummy region, and the peripheral region;
• patterning portions of the precursor electric charge accumulation layer and the sidewall insulation film in the peripheral region and the dummy region adjacent to the peripheral region to form a laminated layer film and a second sidewall on the second extension region and one or both of side surfaces of the second gate electrode in the longitudinal direction;
• patterning remaining portions of the precursor electric charge accumulation layer and the sidewall insulation film in the memory cell region and a remaining area of the dummy region to form an electric charge accumulation layer and a first sidewall on the first extension region and one or both of side surfaces of the first gate electrode facing each other in the longitudinal direction.