Compensation for slurry composition in in-situ electromagnetic inductive monitoring
AssigneeApplied Materials, Inc.
InventorsKun Xu, Andrew Siordia
Life of this patent
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Abstract
A method of chemical mechanical polishing includes bringing a conductive layer of a substrate into contact with a polishing pad, supplying a polishing liquid to the polishing pad, generating relative motion between the substrate and the polishing pad, monitoring the substrate with an in-situ electromagnetic induction monitoring system as the conductive layer is polished to generate a sequence of signal values that depend on a thickness of the conductive layer, and determining a sequence of thickness values for the conductive layer based on the sequence of signal values. Determining the sequence of thickness values includes at least partially compensating for a contribution of the polishing liquid to the signal values.
Claims17
A computer program product tangibly encoded on a computer readable media, comprising instructions to cause a computer system to:
- store a polishing liquid signal contribution value representing a contribution of a polishing liquid to signals values generated by an in-situ electromagnetic induction monitoring system during polishing of a substrate in the presence of the polishing liquid, the contribution to the signal values due to a magnetic field from a sensor of the in-situ electromagnetic induction monitoring system impinging the polishing liquid;
- receive a sequence of signal values from the in-situ electromagnetic induction monitoring system that depend on a thickness of a conductive layer on the substrate as the substrate is polished in the presence of the polishing liquid;
- determine a sequence of thickness values for the conductive layer based on the sequence of signal values and the polishing liquid signal contribution value;
- and
- at least one of determine a polishing endpoint or adjusting a polishing parameter of the polishing system based on the sequence of thickness values.
A polishing system, comprising:
- a rotatable platen to support a polishing pad;
- a carrier head to hold a substrate against the polishing pad;
- a dispenser to supply a polishing liquid to the polishing pad;
- an in-situ electromagnetic induction monitoring system including a sensor to generate a sequence of signal values that depend on a thickness of a conductive layer on the substrate and composition of the polishing liquid;
- and
- a controller configured to
- store a polishing liquid signal contribution value representing a contribution of the polishing liquid to signals values generated by the in-situ electromagnetic induction monitoring system during polishing of the substrate in the presence of the polishing liquid, the contribution to the signal values due to a magnetic field from a sensor of the in-situ electromagnetic induction monitoring system impinging the polishing liquid;
- receive a sequence of signal values from the in-situ electromagnetic induction monitoring system as the substrate is polished in the presence of the polishing liquid;
- determine a sequence of thickness values for the conductive layer based on the sequence of signal values and the polishing liquid signal contribution value;
- and
- at least one of determine a polishing endpoint or adjusting a polishing parameter of the polishing system based on the sequence of thickness values.
Dependencies are inferred from the claim text.