Method of fabricating flash memory device

A method of fabricating a flash memory device, the method comprising:

• sequentially forming an etching object layer and a lower sacrificial layer on a substrate;
• forming a plurality of upper sacrificial pattern structures on the lower sacrificial layer;
• forming a plurality of upper spacers by covering side walls of the upper sacrificial pattern structures;
• forming a plurality of lower sacrificial pattern structures, by etching the lower sacrificial layer using the upper spacers as an etch mask;
• forming a lower spacer layer covering the plurality of lower sacrificial pattern structures;
• forming a lower mask pattern, including a plurality of line masks, by etching the lower spacer layer and at least a portion of lower sacrificial pattern structure;
• and
• forming a first line pattern, and a second line pattern by etching the etching object layer, by using the lower mask pattern as an etch mask,
• wherein the first line pattern is a selection line including a string selection line (SSL) or a ground selection line (GSL), and each of the second line patterns is a word line (WL).

A method of fabricating a flash memory device, the method comprising:

• sequentially forming an etching object layer and a lower sacrificial layer on a substrate;
• forming a plurality of upper sacrificial pattern structures on the lower sacrificial layer;
• forming a plurality of upper spacers by covering side walls of the upper sacrificial pattern structures;
• forming plurality of lower sacrificial pattern structures, by etching the lower sacrificial layer using the upper spacers as an etch mask;
• forming a lower spacer layer covering the plurality of lower sacrificial pattern structures;
• forming a lower mask pattern, including a plurality of line masks, by etching the lower spacer layer and at least a portion of lower sacrificial pattern structure;
• and
• forming a first line pattern, and a second line pattern by etching the etching object layer, by using the lower mask pattern as an etch mask, wherein the forming of the upper spacer includes
• forming an upper spacer layer covering the upper sacrificial pattern structures;
• forming a first photoresist pattern exposing a portion of the upper spacer layer such that the photoresist covers a region of the upper spacer layer at a first side wall of the upper sacrificial pattern structure;
• and
• forming the upper spacer by using the first photoresist pattern as an etch mask.