The present disclosure relates to the field of photolithography technologies. Disclosed is a mask comprising a transparent substrate, the transparent substrate being provided thereon with a semi-transmitting film layer and a light barrier layer to form a non-transmitting region, a semi-transmitting region, and a full transmitting region, the transparent substrate being further provided with a light extinction film layer located at a vicinity of the full transmitting region to weaken an intensity of ultraviolet light transmitting through the vicinity of the full transmitting region. The size of the via formed after an exposure process with the mask is less affected by a change in the thickness of the photoresist surrounding the via.