A method for manufacturing a semiconductor device includes sequentially forming an insulating layer and a metal layer over a semiconductor substrate, forming a photoresist pattern over the metal layer and etching the metal layer using the photoresist pattern as an etching mask to form a metal line pattern, subjecting the photoresist pattern to a reflow process to form a photoresist pattern over the metal layer and etching the metal layer using the photoresist pattern as an etching mask to form a metal line pattern, subjecting the photoresist pattern to a reflow process to form a reflowed photoresist pattern surrounding the metal line pattern, forming a metal-insulator-metal (MIM) layer over the semiconductor substrate provided with the reflowed photoresist pattern, and removing the MIM layer arranged over the photoresist pattern and the photoresist pattern.