Technologies related to forming metal lines of a semiconductor device are disclosed. A method of forming metal lines of a semiconductor device may include forming at least one interlayer insulating layer on a semiconductor substrate, forming via holes and trenches in the at least one interlayer insulating layer, forming an anti-diffusion film on the via holes and the trenches, depositing a seed Cu layer on the anti-diffusion film, after the seed Cu layer is deposited, depositing rhodium (Rh), and forming Cu line on the deposited Rh. The Rh improves an adhesive force between Cu layers and prevents oxide materials or a corrosion phenomenon from occurring on the seed Cu layer. Accordingly, occurrence of delamination in subsequent processes (for example, annealing and CMP) can be prevented or reduced.