A method for forming a fine pattern of a semiconductor device comprises forming a deposition pattern including first, second, and third mask patterns over a semiconductor substrate having an underlying layer, side-etching the second mask pattern with the third mask pattern as an etching barrier mask, removing the third mask pattern, forming a spin-on-carbon layer that exposes the upper portion of the second mask pattern, performing an etching process to expose the underlying layer with the spin-on-carbon layer as an etching barrier mask, and removing the spin-on-carbon layer.