Underlayer topography metal residue detection and overpolishing strategy

A polishing apparatus for processing a substrate, comprising:

• a polishing pad support;
• a carrier head configured to hold the substrate and apply one or more independently controllable pressures to a plurality of regions of the substrate;
• an in-situ monitoring system to monitor a characteristic of substrate within the plurality of regions during polishing;
• and
• a controller that includes computer program instructions that are stored in memory, which when executed by a processor of the controller cause:
• (a) polishing a surface of the substrate by causing the carrier head to urge the substrate against a surface of a polishing pad positioned on the polishing pad support;
• (b) the in-situ monitoring system to detect a first substrate measurement corresponding to a first region of the substrate;
• (c) the in-situ monitoring system to detect a second substrate measurement corresponding to a second region of the substrate;
• (d) the controller to determine that a slope of the first or the second series of measurement values is within a threshold slope;
• (e) the controller to determine, based on determining that the slope of the first or the second series of measurement values is within the threshold slope, a difference in the first substrate measurement relative to the second substrate measurement;
• and
• (f) the controller to provide an indication in response to the determined difference being outside of a tolerance threshold.

A polishing apparatus for processing a substrate, comprising:

• a polishing pad support;
• a carrier head configured to hold the substrate and apply one or more independently controllable pressures to a plurality of regions of the substrate;
• a controller that includes computer program instructions that are stored in memory, which when executed by a processor of the controller that cause to controller to:
• (a) polish a surface of the substrate by causing the carrier head to urge the substrate against a surface of a polishing pad positioned on the polishing pad support;
• (b) generate a first series of substrate measurements corresponding with a first region of the substrate;
• (c) generate a second series of substrate measurements corresponding with a second region of the substrate;
• (d) determine a slope of the first series of substrate measurements over time;
• (e) determine a slope of the second series of substrate measurements over time;
• (f) determine that the slope of the first series of substrate measurements or the slope of the second series of substrate measurements is within a threshold range;
• (g) determine a difference between the first series of substrate measurements and the second series of substrate measurements, based on a determination that the slope of the first series of substrate measurements or the slope of the second series of substrate measurements is within the threshold range;
• (h) stop the polishing of the surface of the substrate in response to a determination that the difference between the first series of substrate measurements and the second series of substrate measurements is within a tolerance threshold;
• (i) indicate that the first series of substrate measurements and the second series of substrate measurements are outside the tolerance threshold in response to a determination that the first series of substrate measurements and the second series of substrate measurements is outside the tolerance threshold and update an aspect of the polishing the surface of the substrate and repeating (a)-(c) and (g);
• and
• (j) indicate that the first series of substrate measurements and the second series of substrate measurements cross into the tolerance threshold in response to a determination that the first series of substrate measurements and the second series of substrate measurements cross into the tolerance threshold.