A method of fabrication of a semiconductor integrated circuit device uses a mark having, on a first main surface of a mask substrate, a first light transmitting region, a second light transmitting region disposed at the periphery of the first light transmitting region and permitting inversion of the phase of light transmitted through the second light transmitting region relative to light transmitted through the first light transmitting region, and a light shielding region disposed at the periphery of the second light transmitting region. The second light transmitting region is formed from a first film deposited over the first main surface of the mask substrate, said light shielding region is formed by a second film deposited over the first main surface of the mask substrate via said first film, and at least one of said first film and second is formed from a resist film.