A method for manufacturing a multi-level interconnection structure in a
semiconductor device includes the steps of consecutively forming an
anti-diffusion film and an interlevel dielectric film on a first level Cu
layer, forming first through third hard mask films on the interlevel
dielectric film, etching the interlevel dielectric film by using the
first hard mask to form first through-holes, etching the first and second
hard mask films and a top portion of the interlevel dielectric film by
using the third hard mask film to form trenches, and etching the
anti-diffusion film to form through-holes. The first hard mask film
protects the interlevel dielectric film during removal of the second and
third hard mask films.