Abstract: A method includes forming a material layer over a substrate, forming a first hard mask (HM) layer over the material layer, forming a first trench, along a first direction, in the first HM layer. The method also includes forming first spacers along sidewalls of the first trench, forming a second trench in the first HM layer parallel to the first trench, by using the first spacers to guard the first trench. The method also includes etching the material layer through the first trench and the second trench, removing the first HM layer and the first spacers, forming a second HM layer over the material layer, forming a third trench in the second HM layer. The third trench extends along a second direction that is perpendicular to the first direction and overlaps with the first trench. The method also includes etching the material layer through the third trench.

Abstract: A method of manufacturing a mark including the following steps is provided. A substrate including a device area and a mark area is provided. A dielectric layer is formed on the substrate. A dual damascene opening is formed in the dielectric layer of the device area. The dual damascene opening includes a first opening and a second opening connected to each other. The width of the second opening is greater than the width of the first opening. A third opening is formed in the dielectric layer of the mark area. The third opening and the first opening are simultaneously formed by the same process. A barrier material layer is formed on the surfaces of the dual damascene opening and the third opening. The barrier material layer seals the third opening to form a void in the third opening. A metal material layer is formed on the barrier material layer.