Selectivity between materials being polished over the lifetime of the CMP consumable set will typically change. Changes in selectivity overtime are varied and complex, but one main contributor identified in this study using Sensofar immersion metrology, is the changing state of the polishing pad asperities overtime (aka Glazing).

  This study (of a damascene process) demonstrated;

    --> Successful monitoring of the same “wet” polishing pad while on the platen.

    --> Identification of multiple points in usage when glazing occurred

    --> Characterization of successful interventions to reverse the glazing effect

    --> Successful return to target selectivity

    --> Longer consumable lifetime

    --> Reduced manufacturing downtime (MTTR).