DAMASCENE COPPER ELECTROPLATING FOR CHIP INTERCONNECTIONS

Damascene Cu electroplating for on-chip metallization, which we concei ved and developed in the early 1990s, has been central to IBM's Cu chi p interconnection technology. We review here the challenges of filling trenches and vias with Cu without creating a void or seam, and the di scovery that electrodeposition can be engineered to give filling perfo rmance significantly better than that achievable with conformal step c overage. This attribute of superconformal deposition, which we call su perfilling, and its relation to plating additives are discussed, and w e present a numerical model that represents the shape-change behavior of this system.