Study of the Dynamics of Local Particle Removal Efficiencies Using Localized Haze Maps

The local particle removal efficiency (PRE) of nano particles in megasonic cleaning experiments is studied. This approach makes it possible to quantify non uniform cleaning effects over the wafer and to look into the dynamics of particle removal at different areas on the wafer. A direct correlation between PRE and megasonic induced damage of device structures demonstrates that a considerable amount of damage is already formed at less efficiently cleaned areas of the wafer.