A method for fabricating a semiconductor device includes the steps of: forming a first inter-metal dielectric (IMD) layer on a substrate; forming a first patterned mask on the first IMD layer, in which the first patterned mask includes a first slot extending along a first direction; forming a second patterned mask on the first patterned mask, in which the second patterned mask includes a second slot extending along a second direction and the first slot intersects the second slot to form a third slot; and forming a first metal interconnection in the third slot.