A completely ionized and clustered beam of Mo or Cu is deposited with variable kinetic energy on a substrate, and the filling of micron-sized contact holes on semiconductor devices is studied. An excellent hole filling is obtained for the impact of charged copper clusters, if they contain 1000-3000 Cu atoms and impinge with a kinetic energy of about 10 eV per atom on a substrate having a temperature of 500 K. The morphology of small hole fillings by slow and energetic cluster impact is discussed.