The present disclosure improves characteristics and reliability of a device by preventing seams within a copper layer, wherein seams are created when forming a copper line by a damascene process. Such seams created within a first and a second copper layer are prevented by a process in which the first copper layer and the second copper layer are deposited at constant speeds when the first copper layer is firstly formed only in a via hole by leaving a first copper seed layer only in the via hole, and then the second copper layer is formed in a trench by forming a second copper seed layer in the trench.
