XeCl excimer laser (λ=308 nm) was used to melt and flow sputter deposited Cu film into contacts and trenches of different depths to fill them and to achieve a planarized surface. The process windows (in terms of laser fluence at substrate temperatures of 20, 365, and 440 °C) for the planarization and complete fill were investigated. We found that it is possible to completely fill the contacts and trenches of 1 μm in width and 1 μm in depth with an appreciable process window. However, we were only able to fill these 1 μm wide contacts and trenches of 2 μm in depth at 440 °C. The results and other phenomena will be discussed.