The disclosure relates to a method and apparatus for enhancing copper film
quality with a two-step deposition. The two step deposition may include
depositing a first copper film by electrochemical plating, annealing the
first copper film at a desired temperature for a duration of time to
remove any impurities, depositing a second copper film and annealing the
second copper film for a duration of time to remove impurities. The
second copper film can be deposited by electrochemical plating without
HCl/C-based additive. The second copper film can also be deposited by
sputtering to avoid impurities including C, Cl and S.