The invention provides a formation method of a dual damascene structure. The formation method of the dual damascene structure comprises the steps of providing a substrate, forming a
dielectric layer on the surface of the substrate, forming a through hole in the
dielectric layer, forming a bottom antireflection layer in the through hole in such a manner that the through hole is full of the bottom antireflection layer and the surface of the
dielectric layer is covered, forming, on the surface of the bottom antireflection layer, a
mask layer with an opening which is located above the through hole in position and exposes partial surface of the bottom antireflection layer, removing the partial bottom antireflection layer which is located on the surface of the
dielectric layer under the opening and exposing the surface of partial
dielectric layer and the surface of the bottom antireflection layer in the through hole,
etching the
dielectric layer and the bottom antireflection layer in the through hole along the opening to form a first groove, removing the rest bottom antireflection layer in the through hole, and
etching the dielectric layer along the first groove to form a second groove. The formation method is capable of improving the flatness of the inner wall of the damascene structure.