Patent ID: 9472475
Filing Date: 2016-10-18
CPC Classification: B24B,H01L

Claim Text:
1. A method of controlling polishing, comprising: prior to polishing of a first substrate, storing a desired ratio, the desired ratio representing a desired ratio determined prior to polishing of a substrate for a clearance time of a first zone of the substrate to a clearance time of a second zone of the substrate, and wherein the desired ratio indicates that the clearance time of the first zone differs from the clearance time of the second zone; polishing the first substrate, wherein the first substrate has an overlying layer on an underlying layer or layer structure; during polishing of the first substrate, monitoring the overlying layer with an in-situ monitoring system and generating a sequence of measurements from the in-situ monitoring system; sorting the measurements into a first group associated with the first zone of the first substrate and a second group associated with the second zone on the first substrate; determining a first time at which the overlying layer is cleared from the first zone on the first substrate based on the measurements from the first group; determining a second time at which the overlying layer is cleared from the second zone on the first substrate based on the measurements from the second group; calculating at least one adjusted polishing pressure for the first zone based on a first pressure applied in the first zone during polishing the first substrate, the first time, the second time, and the desired ratio; and polishing a second substrate using the at least one adjusted polishing pressure for the first zone, the adjusted polishing pressure being such that a ratio of a clearance time of the first zone of the second substrate to a clearance time of the second zone of the second substrate is closer to the desired ratio than without such adjustment, and such that the desired ratio provides a difference between the clearance time of the first zone of the second substrate and the clearance time of the second zone of the second substrate.