using a mask to define a spacer for the active gate so that the photoresist film pattern 114 is formed the photoresist film 114 is formed to completely cover the exposed first spacer oxide film 110 and to overlap predetermined regions of the first hard mask patterns 108 a and the polysilicon layer 112 which are formed at both sides of the first spacer oxide film 110 referring to fig2 e the first hard mask patterns 108 a the polysilicon layer 112 and the first spacer oxide film 110 formed under the polysilicon 112 are etched using the photoresist pattern 114 as an etch mask until the hard mask teos layer 106 is exposed thereby forming a second hard mask pattern 116 that is the second hard mask pattern 116 which includes the first spacer oxide film 110 is formed referring to fig2 f the second spacer oxide film 118 for forming the active gate spacer is formed over the second hard mask pattern 116 and over the exposed hard mask teos layer 106 that is a spacer for forming the active gate is formed at sidewalls of the second hard mask pattern 116 the second spacer oxide film 118 is formed to have the same thickness as that of the active gate 22 and is thicker than the first spacer oxide film 110 the thickness of the second spacer oxide film 118 thus defines the thickness of the active gate 22.