A lower mask layer and a first resist layer are formed on a substrate. The first resister is exposed with the use of an exposure mask having a phase shifter. A part of the first resist layer corresponding to the edge of the phase shifter becomes an unexposed part so that an aperture in slit is formed in the first resist layer by developing. The first mask layer is etched through said first resist layer to form an aperture for forming a gate electrode. A second resist layer as an upper mask layer is formed over the lower mask layer. The second resist layer is exposed with the use of the same exposure mask, and is then developed. By setting the exposure strength to a value lower than an exposure strength for exposure to the first resist layer, a wider aperture is formed in the second resist layer. With the use of the lower mask layer having the narrower aperture and the upper mask layer having the wider upper mask layer, a T-shape electrode is formed.