Laser induced activation of fine lines and micro via-holes on aluminium nitride for electroless copper plating is studied. Differing from traditional techniques, this method is demonstrated as an additive and precursorless process, which requires fewer processing steps with good reliability. Ultraviolet, visible and infrared lasers are applied to activate aluminium nitride surfaces. The relations between the quality of activation and laser wavelength, energy density, repetition rate and repetition are described. Depth-dependent activation and metallization of micro via-holes in aluminium nitride using this method are observed and reported for the first time. (C) 2011 Elsevier B. V. All rights reserved.