Wiring structure of a semiconductor device, method of forming the wiring structure, non-volatile memory device including the wiring structure, and method of manufacturing the non-volatile memory device

A method of manufacturing a non-volatile memory device, comprising:

• forming a cell string on a substrate, the cell string including cell transistors arranged in a first direction;
• forming a string selection transistor and a ground selection transistor at both ends of the cell string, respectively;
• covering the cell string, the string selection transistor and the ground selection transistor with a first insulation interlayer, the first insulation interlayer having a linear trench structure that exposes an upper surface of the substrate corresponding to a common source region at a side of the ground selection transistor and extends in a second direction substantially perpendicular to the first direction, and the linear trench structure having a first trench that has a first width and a second trench that is in communication with a lower portion of the first trench and has a second width narrower than the first width;
• forming a common source line in the linear trench structure, the common source line having an upper width and a lower width narrower than the upper width;
• forming a second insulation interlayer on the first insulation interlayer and the common source line, the second insulation interlayer having a contact hole that partially exposes an upper surface of the common source line;
• and
• forming a contact plug in the contact hole,
• wherein forming the first insulation interlayer having the linear trench structure includes:
• forming a preliminary first insulation interlayer on the substrate to cover the cell string, the string selection transistor and the ground selection transistor;
• forming a mask pattern on the preliminary first insulation interlayer, forming the mask pattern includes:
• sequentially forming an amorphous carbon layer, a buffer layer, an organic anti-reflective layer and a photoresist film on the preliminary insulation interlayer,
• patterning the photoresist film to form a photoresist pattern, and
• etching the organic anti-reflective layer, the buffer layer and the amorphous carbon layer using the photoresist pattern as an etching mask;
• anisotropically etching the preliminary first insulation interlayer using the mask pattern as an etching mask to form a preliminary first trench;
• isotropically etching, with the mask pattern remaining on the preliminary first insulation interlayer, the preliminary first insulation interlayer exposed through the preliminary first insulation interlayer exposed through the preliminary first trench to form the first trench having the first width;
• and
• anisotropically etching the preliminary first insulation interlayer exposed through the first trench using the mask pattern as an etching mask to form the second trench having the second width.