Method for manufacturing semiconductor device using polymer

A method for manufacturing a semiconductor device, comprising:

• forming a first insulating layer on a substrate;
• forming an antireflective coating layer on the first insulating layer;
• forming a first photoresist pattern over the antireflective coating layer, the first photoresist pattern having a first opening;
• etching the antireflective coating layer and the first insulating layer through the first opening to a predetermined depth, using the first photoresist pattern as a mask;
• forming a polymer around the first photoresist pattern and on the etched first insulating layer, the polymer having a second opening that exposes a portion of the etched first insulating layer;
• etching the first insulating layer exposed through the second opening using the polymer as a mask until a portion of the substrate is exposed;
• removing the polymer and the first photoresist pattern;
• forming a gate insulating layer on the exposed portion of the substrate;
• forming a polysilicon layer on the gate insulating layer and the first insulating layer;
• planarizing the polysilicon layer until the first insulating layer is exposed;
• forming a second photoresist pattern on the first insulating layer and the planarized polysilicon layer;
• and
• etching the polysilicon layer and the first insulating layer using the second photoresist pattern as a mask to form a gate;
• wherein forming the polymer is performed separately from etching the first insulating layer exposed through the second opening.