Filtering during in-situ monitoring of polishing
AssigneeApplied Materials, Inc.
InventorSivakumar Dhandapani
Life of this patent
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Abstract
A method of controlling polishing includes polishing a substrate, monitoring the substrate during polishing with an in-situ monitoring system, filtering a signal from the monitoring system to generate a filtered signal, and determining at least one of a polishing endpoint or an adjustment for a polishing rate from the filtered signal. The filtering includes modelling a plurality of periodic disturbances at a plurality of different frequencies using a plurality of disturbance states, modelling an underlying signal using a plant state, and applying a linear prediction filter to the plant state and the plurality of disturbance states to generate a filtered signal representing the underlying signal.
Claims12
A computer program product for controlling a polishing system, the computer program product comprising a non-transitory computer-readable medium having instructions which when executed cause one or more computers to:
- receive, during polishing of a substrate, a signal from an in-situ monitoring system of the polishing system, the signal including a sequence of measured values;
- filter the signal to generate a filtered signal, the filtered signal including a sequence of adjusted values, wherein the instructions to filter the signal include instructions to
- model a plurality of periodic disturbances, using a plurality of disturbance states, at a plurality of different frequencies,
- model an underlying signal, using a plant state, and
- apply a linear prediction filter to the plant state and the plurality of disturbance states to generate the filtered signal representing the underlying signal;
- and
- cause the polishing system to at least one of halt polishing of the substrate or adjust a polishing rate of the substrate based on the filtered signal.
Dependencies are inferred from the claim text.