US Patent 7811930 Manufacturing method of dual damascene structure

A manufacturing method of a dual damascene structure is provided. First, a first dielectric layer, a second dielectric layer, and a mask layer are formed. A first trench structure is formed in the mask layer. A via structure is formed in the mask layer, the second dielectric layer, and the first dielectric layer. A portion of the second dielectric layer is then removed, so as to transform the first trench structure into a second trench structure. Here, a bottom of the second trench structure exposes the first dielectric layer.