Measuring the PWP Improvement in the Handling Component of a Semiconductor Process Tool from Air Ionization

The purpose of this experiment was to assess the importance of electrostatic attraction in contamination control in a semiconductor fab. Wafer handling was studied in a cryogenic cleaning tool in a working 300-millimeter (mm) fab in the United States. The particles per wafer pass (PWP, >200 nanometers [nm]) was reduced from 0.455±0.058 to 0.245±0.046 through the use of air ionization. While the tool is one of the cleanest in the fab, the tool still exhibited a large percentage improvement in contamination level by the addition of air ionization.