Methods and apparatus for chemical-mechanical polishing utilizing low suspended solids polishing compositions

Abstract

The present invention provides chemical-mechanical polishing (CMP) methods and apparatus suitable for polishing a substrate utilizing a low suspended solids slurry composition. The CMP methods of the invention comprise polishing a substrate with CMP slurry containing a low suspended solids level (e.g., about 0.01 percent by weight to about 1.0 percent by weight) of a particulate abrasive material in a CMP apparatus, while continuously monitoring and accurately maintaining a predetermined total suspended solids (TSS) level in the slurry. Preferably, maximum TSS variability of the slurry is less than about 20 percent (i.e., ±20% of the target TSS level), more preferably less than about 10 percent TSS variability (i.e., ±10% of the target TSS level) during the course of the polishing process.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application claims the benefit of U.S. Provisional Patent Application Ser. No. 61 / 201,001, filed on Dec. 5, 2008, which is incorporated herein by reference.FIELD OF THE INVENTION[0002]This invention relates to polishing methods and apparatus for polishing a substrate. More particularly, this invention relates to chemical-mechanical polishing methods and apparatus utilizing low suspended solids abrasive polishing compositions.BACKGROUND OF THE INVENTION[0003]Compositions and methods for chemical-mechanical polishing (CMP) the surface of a substrate are well known in the art. Polishing compositions (also known as polishing slurries, CMP slurries, and CMP compositions) for polishing metal-containing surfaces of semiconductor substrates (e.g., integrated circuits) typically contain abrasives, various additive compounds, and the like, and frequently are used in combination with an oxidizing agent. Such CMP compositions are often designed ...

AI Technical Summary

Benefits of technology

[0010]When the TSS level of the low level abrasive slurry is maintained within a tight variance, the performance characteristics of the substrate polishing process are desirably enhanced. For example, the variability in substrate removal rate and / or defectivity desirably can be reduced due to the reduced variability in TSS level. This is particularly pronounced in slurries containing low levels of suspended particulate abrasive material. The tight process control provided by the methods and apparatus of the present invention can lead, for example, to improved polishing productivity, reduced levels of reworking, more predictable substrate throughput, and reduced production costs relative to conventional polishing methods without tight TSS control.

Problems solved by technology

In some cases the slurry TSS level may be adversely affected by insufficient mixing or agitation in the slurry delivery system, in which case the TSS level may be adjusted by changing the mixing parameters or configuration of the slurry delivery system.

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