Determination of position of sensor measurements during polishing

A method of polishing, comprising:

• bringing a surface of a substrate into contact with a polishing pad, the substrate being held by a carrier head;
• causing relative motion between the substrate and the polishing pad;
• using an in-situ monitoring sensor to generate a measurement of a substrate property;
• associating the measurement of the substrate property with information indicating a time when the measurement of the substrate property was made;
• generating a measurement of a position of the carrier head;
• and
• using the first measurement of the position of the carrier head, the time when the measurement of the substrate property was made, and a phase adjustment representing lag resulting from a processing delay in generating the measurement of the position of the carrier head in determining a position on the substrate where the measurement of the substrate property was taken.

A computer program product, tangibly stored on machine-readable medium, for operating a polishing apparatus, the product comprising instructions operable to cause a processor to:

• bring a surface of a substrate into contact with a polishing pad, the substrate being held by a carrier head;
• cause relative motion between the substrate and the polishing pad;
• receive a series of measurements of one or more properties of the substrate from one or more in-situ monitoring sensors;
• associate each measurement of the series with information indicating a time when the measurement was made;
• receive a plurality of carrier-head position measurements, each indicating a position of the carrier head;
• curve fit a sinusoidal first function to the plurality of carrier-head position measurements to define a second function for associating measurements from the series with positions on the substrate;
• and
• for each measurement in the series, use the second function to determine a position on the substrate where the measurement was taken.

A computer program product, tangibly stored on machine-readable medium, for operating a polishing apparatus, the product comprising instructions operable to cause a processor to:

• bring a surface of a substrate into contact with a polishing pad, the substrate being held by a carrier head;
• cause relative motion between the substrate and the polishing pad;
• receive a measurement of a substrate property from an in-situ monitoring sensor;
• associate the measurement of the substrate property with information indicating a time when the measurement of the substrate property was made;
• receive a measurement of a position of the carrier head;
• and
• use the first measurement of the position of the carrier head, the time when the measurement of the substrate property was made, and a phase adjustment representing lag resulting from a processing delay in generating the measurement of the position of the carrier head in determining a position on the substrate where the measurement of the substrate property was taken.