Patent ID: 7774086
Filing Date: 2010-08-10
Classification: B24B,B24D,H01L

Abstract:
1. A computer program product, encoded on a computer-readable device, operable to cause a data processing apparatus to perform operations, comprising: obtaining a first spectrum of reflected light from a first zone on a substrate and a second spectrum from a second zone on the substrate during a polishing sequence; comparing the first spectrum and the second spectrum to a spectra library to determine a first index for the first spectrum and a second index for the second spectrum; obtaining a third spectrum of reflected light from the first zone and a fourth spectrum from the second zone at a different time during the polishing sequence; comparing the third spectrum and the fourth spectrum to the library to determine a third index for the first zone and a fourth index for the second zone; determining a polishing rate at the first zone from the first index and the third index and a polishing rate at the second zone from the second index and the fourth index; and based on the first polishing rate, the second polishing rate, a first target relative thickness for the first zone and a second target relative thickness for the second zone, determining an adjusted polishing rate for the second zone to cause the second zone to be polished to the second target relative thickness at substantially the same time as the first zone is polished to the first target relative thickness.