The effect of the stress and grain size of the seed layer deposited on TaN and Ta/TaN barrier films on the properties of electroplated copper interconnection layer is described. Properties such as resistivity and grain size are studied. The effect of chemicals employed for electroplating the copper layer is also studied after deposition on these seed layers. A lower resistivity copper layer can be obtained by reducing stress and by growing grain size in the seed and interconnection layers. (C) 2004 The Electrochemical Society.