Peak-based endpointing for chemical mechanical polishing
AssigneeApplied Materials, Inc.
InventorsDominic J. Benvegnu, Boguslaw A. Swedek, David J. Lischka
Life of this patent
Estimating the term…
Abstract
A polishing system receives one or more target parameters for a selected peak in a spectrum of light, polishes a substrate, measures a current spectrum of light reflected from the substrate while the substrate is being polished, identifies the selected peak in the current spectrum, measures one or more current parameters of the selected peak in the current spectrum, compares the current parameters of the selected peak to the target parameters, and ceases to polish the substrate when the current parameters and the target parameters have a pre defined relationship.
Claims12
A polishing endpoint detection system, comprising:
- a light source to direct a light to a substrate while the substrate is being polished;
- a spectrometer to measure a sequence of current spectra of light reflected from the substrate while the substrate is being polished;
- and
- a controller configured such that in operation the controller will
- store a predetermined number for detecting an endpoint,
- receive the sequence of current spectra from the spectrometer,
- identify a plurality of peaks or valleys in the sequence of current spectra, wherein the peaks or valleys persist with an evolving location through at least some of the sequence of current spectra,
- count a number of peaks or valleys that were identified that pass a predetermined location as polishing progresses, and
- generate a signal to halt polishing of the substrate when the number counted reaches the predetermined number.
Dependencies are inferred from the claim text.