Patent ID: 6254453
Filing Date: 2001-07-03
Classification: G01N

Abstract:
A method to optimize the chemical mechanical planarization process of wafers having a target removal layer and a stop layer comprising,adding slurry to a polishing table, said polishing table comprising a polishing pad and a platen adapted for rotation,allowing a portion of said slurry to engage an interface between said polishing pad and said wafer,continuously extracting a gaseous sample from said slurry, said gaseous sample further comprising a reactant product created when said polishing pad engages said stop layer,introducing the said gaseous sample to a reactant product detector,determining a first time corresponding to an initial detection of said reactant product in said slurry thereby creating a first reference point,determining a second time corresponding to the detection of a maximum volume of said reactant in said slurry, thereby creating a second reference point, andprocessing said first and said second reference points to result in a signal, wherein said signal reflects the uniformity of removal of said layer containing said reactant product.