Combined eddy current sensing and optical monitoring for chemical mechanical polishing
AssigneeApplied Materials, Inc.
InventorsNils Johansson, Boguslaw A. Swedek, Manoocher Birang
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Abstract
A chemical mechanical polishing apparatus has a polishing pad, a carrier to hold a substrate against a first side of the polishing surface, and a motor coupled to at least one of the polishing pad and carrier head for generating relative motion therebetween. An eddy current monitoring system is positioned to generate an alternating magnetic field in proximity to the substrate, an optical monitoring system generates a light beam and detects reflections of the light beam from the substrate, and a controller receives signals from the eddy current monitoring system and the optical monitoring system.
Claims16
A method of chemical mechanical polishing, comprising:
- positioning a substrate in contact with a polishing surface of a polishing pad;
- creating relative motion between the substrate and the polishing surface;
- generating a first signal from an eddy current monitoring system that includes a coil and a ferromagnetic core, each of which being situated at least partially in a cavity in a platen below the polishing pad;
- generating a second signal from an optical monitoring system that includes a light source and a light detector, each of which being situated at least partially in the cavity;
- and
- monitoring the first and second signals with a controller for endpoint criteria.
Dependencies are inferred from the claim text.