Chemical mechanical polishing apparatus with non-conductive elements
AssigneeApplied Materials, Inc.
InventorsDoyle E. Bennett, Sandeep R. Koppikar, Jeffrey Drue David, Boguslaw A. Swedek, Nils Johansson
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Abstract
Conductive elements of a chemical mechanical polishing system may generate undesired eddy currents under the influence of a time-dependent magnetic field used in an eddy current monitoring system. To improve the accuracy of an eddy current monitoring system, elements that may contribute an undesired signal to the sensed eddy current signal may be fabricated from a non-conductive material such as plastic or ceramic. In some implementations, elements may be fabricated from non-magnetic materials.
Claims20
A carrier head, comprising:
- a substrate backing assembly having non-conductive rigid components, the substrate backing assembly to provide a mounting surface for a substrate to be polished.
A carrier head comprising:
- a housing to be secured to a drive shaft, the housing including one or more housing elements;
- a base assembly, the base assembly including one or more base elements, the one or more base elements including means for permitting the base assembly to move with respect to the housing;
- and
- a flexible membrane secured to the base assembly, the flexible membrane having a lower surface that provides a substrate-mounting surface, and wherein the base elements having at least a portion within a minimum distance of the lower surface are non-conductive, and further wherein the housing elements having at least a portion within the minimum distance are non-conductive.
A polishing system, comprising:
- a polishing pad having a polishing surface;
- a carrier to hold a substrate against the polishing surface of the polishing pad;
- and
- an eddy current monitoring system including an induction coil positioned on a side of the polishing surface opposite the substrate, the induction coil to generate a magnetic field through the pad into a sensing region of the system, wherein components of the polishing system with at least a portion positioned within a sensing distance of the polishing pad in the sensing region are nonconductive.
Dependencies are inferred from the claim text.