Endpoint compensation in electroprocessing

Abstract

Method for process control of electro-processes is provided. In one embodiment, the method includes processing a conductive layer formed on a wafer using a target endpoint, detecting breakthrough of the conductive layer to expose portions of an underlying layer, and adjusting the target endpoint in response to the detected breakthrough. In another embodiment, the target endpoint is adjusted relative to an amount of underlying layer exposed through the conductive layer.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention generally relates to polishing, planarization, plating and combinations thereof. More particularly, the invention relates to the monitoring and control of electro-processing, polishing and plating. 2. Description of the Related Art Sub-quarter micron multi-level metallization is one of the key technologies for the next generation of ultra large-scale integration (ULSI). The multilevel interconnects that lie at the heart of this technology require planarization of interconnect features formed in high aspect ratio apertures, including contacts, vias, trenches and other features. Reliable formation of these interconnect features is very important to the success of ULSI and to the continued effort to increase circuit density and quality on individual wafers and die. In the fabrication of integrated circuits and other electronic devices, multiple layers of conducting, semiconducting, and dielectric materials...

AI Technical Summary

Benefits of technology

In general, embodiments are relating to process control of electro-processing. Some aspects of the invention are generally directed to determining removal of material from a wafer during polishing, to determining an endpoint of a poli

Problems solved by technology

However, the progress of the polishing operation is not easily viewable because of the contact between the wafer and the pad.

In addition, variations in the polishing conditions impede an accurate determination of the polishing endpoint.

However, this method is time consuming, and does not account for sudden changes in the removal rate that may occur between measurement intervals.

However, this method does not provide a way of determining the polishing endpoint unless an underlying layer is exposed during polishing.

Additionally, this approach is somewhat erratic in predicting the polishing endpoint unless all of the underlying lines are simultaneously exposed.

Furthermore, the detection apparatus is delicate and subject to frequent breakdown caused by the exposure of the measuring or detecting apparatus to the slurry or electrolytic fluid.

This affects the torque necessary to provide the desired polishing pad speed.

Such changes may mask the exposure of the underlying metal layer, or they may imitate an endpoint condition, leading to a premature stop of polishing.

Thus, while the endpoint detection techniques (including those described above) exist for CMP, the techniques may not be readily extendible to ECMP.

Even where the techniques are extendible to ECMP, doing so may require retrofitting existing processing systems with expensive equipment.

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