A substrate assembly includes: a substrate; a gate structure disposed on the substrate; a conductive line disposed on the substrate, wherein from a top view, the conductive line extends along a first direction; and a conductive structure disposed on the substrate, wherein from the top view, the conductive structure is adjacent to the conductive line and separated from the conductive line, and the conductive structure has an overlapping region overlapping the gate structure, wherein from the top view, the overlapping region extends along a second direction, the first direction and the second direction are different, the overlapping region comprises a first end portion, and the first end portion has a curved shape.