US Patent 7667835 Apparatus and method for preventing copper peeling in ECP

An apparatus and method for preventing the peeling of electroplated metal from a wafer, is disclosed. The apparatus includes a seed layer detector system having a light source and a reflectivity detector. According to the method, the light source emits a beam of light onto a wafer and the reflectivity detector receives the light reflected from the wafer. The reflectivity of the wafer surface is measured to determine the presence or absence of a seed layer on the wafer, as well as whether the seed layer has a minimum thickness for optimum electroplating of a metal onto the seed layer.