Abstract: This is a wafer polishing and planarizing tool in which there is incorporated a separate measuring station and means for moving the wafer and immersing the wafer into the measuring station without removing it from the polishing head. The wafer being treated is quickly, reliably and periodically checked over its entire surface to determine the thickness of any dielectric on its surface. The measuring station contains a plurality of measuring electrodes immersed in an electrolyte so that when the wafer to be measured is introduced into the station not only is the wafer surface cleaned of any slurry or other contaminants but simultaneously the measuring electrodes see a constant medium to provide multi-point thickness measurements across the entire wafer surface. Thus measurement variations due to pad or slurry conditions are eliminated.