Stress in Copper Seed Layer Employing in the Copper Interconnection

Stress of copper seed employing in the copper interconnection layer is studied. Since this stress affects largely the adhesion strength at the Cu/barrier layers and the Cu(111) orientation of copper layer, reduction of stress is important. Higher and high stresses are applied in the layer on TaN and Ta barrier layers. These layers can lead to poor adhesion strength. Much better adhesion strength can be accomplished in the layer on the TaSiN barrier layer. The surface changes to rough surfaces with annealing at 400°C in the layer deposited on TaN. The highly stressed layer changes to a low stress layer as a result of this agglomeration. However, a smooth surface is held in the low stress layer on the TaSiN barrier layer.