Limiting Adjustment of Polishing Rates During Substrate Polishing

摘要

A method of controlling polishing includes polishing a region of a substrate at a first polishing rate, measuring a sequence characterizing values for the region of the substrate during polishing with an in-situ monitoring system, determining a polishing rate adjustment for each of a plurality of adjustment times prior to a polishing endpoint time, and adjusting a polishing parameter to polish the substrate at a second polishing rate. The time period is greater than a period between the adjustment times and the projected time is before the polishing endpoint time. The second polishing rate is the first polishing rate as adjusted by the polishing rate adjustment.

主权项

1. A method of controlling polishing, comprising:
polishing a region of a substrate at a first polishing rate; measuring a sequence characterizing values for the region of the substrate during polishing with an in-situ monitoring system, the characterizing values depending on a thickness of a layer undergoing polishing in the region; for each of a plurality of adjustment times prior to a polishing endpoint time, determining a polishing rate adjustment for the region of the substrate based on the sequence of characterizing values, wherein determining the polishing rate adjustment comprises calculating a desired polishing rate to bring a projected characterizing value to a desired value at a projected time that is a time period after the adjustment time, wherein the polishing rate adjustment is calculated from the first polishing rate and the desired polishing rate, and wherein the time period is greater than a period between the adjustment times and the projected time is before the polishing endpoint time; and adjusting a polishing parameter to polish the substrate at a second polishing rate, the second polishing rate being the first polishing rate as adjusted by the polishing rate adjustment.