Method for monitoring a metal layer during chemical mechanical polishing
AssigneeApplied Materials, Inc.
InventorsHiroji Hanawa, Nils Johansson, Boguslaw Swedek, Manoocher Birang
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Abstract
A sensor for monitoring a conductive film in a substrate during chemical mechanical polishing generates an alternating magnetic field that impinges a substrate and induces eddy currents. The sensor can have a core, a first coil wound around a first portion of the core and a second coil wound around a second portion of the core. The sensor can be positioned on a side of the polishing surface opposite the substrate. The sensor can detect a phase difference between a drive signal and a measured signal.
Claims18
A method of monitoring a thickness of a conductive layer in a substrate during a polishing operation, comprising:
- positioning a substrate on a first side of a polishing surface;
- generating an alternating magnetic field from an inductor positioned on a second side of the polishing surface opposite the substrate, the magnetic field extending through the polishing surface to induce eddy currents in the conductive layer;
- and
- detecting a change in the alternating magnetic field caused by a change in the thickness of the conductive layer.
A method of chemical mechanical polishing, comprising:
- positioning a substrate having a conductive layer on a first side of a polishing surface;
- generating an alternating magnetic field from an inductor positioned on a second side of the polishing surface opposite the substrate, the magnetic field extending through the polishing surface to induce eddy currents in the conductive layer;
- creating relative motion between the substrate and the polishing surface to polish the conductive layer;
- sensing the eddy currents in the substrate;
- and
- halting polishing when the sensed eddy currents exhibit an endpoint criteria.
Dependencies are inferred from the claim text.