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US 8,556,679 B2Granted
Substrate polishing metrology using interference signals
AssigneeApplied Materials, Inc.
InventorsManoocher Birang, Grigory Pyatigorsky
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Abstract
A polishing pad assembly for a chemical mechanical polishing apparatus includes a polishing pad having a polishing surface and a surface opposite the polishing surface for attachment to a platen, and a solid light-transmissive window formed in the polishing pad. The light-transmissive window is more transmissive to light than the polishing pad. The light-transmissive window has a light-diffusing bottom surface.
Claims5
A method of in-situ optical monitoring of a substrate during chemical mechanical polishing, comprising:
- directing a light beam onto the substrate during chemical mechanical polishing;
- measuring an intensity of a reflection of the light beam from the substrate and to generate a signal;
- passing the signal through a high frequency filter;
- and
- passing the signal through a low frequency filter.
2 more elements
Dependencies are inferred from the claim text.