Abstract: Disclosed is a method for fabricating a gate of semiconductor device. The disclosed comprises the steps of: sequentially forming a gate oxide layer, a gate material layer and a mask oxide layer on a semiconductor substrate; coating photopolymer having compound accelerator including polar functional group which absorbs HF vapor and ionize at a predetermined high temperature on the mask oxide layer; exposing the photopolymer and cross-linking the portion of exposed photopolymer; performing DFVP process by passing over HF vapor on the resultant substrate at a predetermined high temperature, thereby developing the portion of exposed photopolymer and etching the portion of mask oxide layer exposed by development of photopolymer simultaneously; removing the residual photopolymer; and etching the gate material layer and the gate oxide layer using the etched mask oxide layer.