A new, in-line method for separating frontside/backside metalilic contamination from implantation

In this study, a new approach to answering the problem of “directional” metallic contamination contaminant introduction from the front or the back or both on a processed wafer is reported. Since dopant activation treatments diffuse metallic contaminants such as Fe throughout a CZ substrate, information as to the directional source of bulk contamination is often lost. However for problem identification, this directional component is critical. Below we propose a new method for solving this problem using surface photovoltage (SPV) which is totally passive and does not adversely effect the wafer or the implant