The Cu/Ru(1 0 (1) over bar 0) adsorption system was investigated by STM, LEED and AES. Cu was deposited at room temperature (RT) and 800 K, with the coverage ranging from a fraction up to 4 bilayers (BL). The first two Cu BL grow in the bilayer-by-bilayer mode. Their structure is pseudomorphic and does not depend on the temperature. For coverage higher than 2 BL, Cu deposited at elevated temperature forms three-dimensional islands in mesa shape with Cu(1 1 1) facets on their tops. The facets and the substrate are epitaxially oriented with Cu(1 1 1)parallel to Ru(1 0 (1) over bar 0) and Cu[0 1 (1) over bar]parallel to|Ru[1 (2) over bar 1 0]. Obtained results can be helpful in search for an optimal method of Cu deposition onto Ru in the damascene process in microelectronics, and could be also of interest to catalysis. (C) 2012 Elsevier B. V. All rights reserved.