Manufacturing method for dual damascene structure

A manufacturing method for a dual damascene structure first includes providing a substrate having at least a dielectric layer, a first hard mask layer, a first cap layer, a second hard mask layer, and a second cap layer sequentially formed thereon, performing a first double patterning process to form a plurality of first trench openings and second trench openings in the second cap layer and the second hard mask, and the first layer being exposed in bottoms of the first trench openings and the second trench openings, performing a second double patterning process to form a plurality of first via openings and second via openings in the first cap layer and the first hard mask layer, and transferring the first trench openings, the second trench openings, the first via openings, and the second via openings to the dielectric layer to form a plurality of dual damascene openings.