Conventional chemical vapor deposition (CVD), physical vapor deposition (PVD), and other techniques are used to deposit electrically conductive material into the contact holes, vias, trenches, or other patterns formed on a substrate. The presence of native or process generated oxides and other contaminants within a feature frequently can result in voids by promoting uneven distribution of the depositing metal. The residual oxides typically form as a result of exposing the exposed film layer/substrate to oxygen or as a byproduct of wafer processing. Oxygen exposure can occur, for example, when moving substrates between processing chambers at atmospheric conditions, or when a small amount of oxygen remaining in a vacuum chamber contacts a substrate/film layer, or when a layer is contaminated by etching, or oxygen exposure during mask removal. Other defects within the features formed on a substrate can be sputtered material from an oxide over-etch, residual photoresist from a stripping process, leftover hydrocarbon or fluorinated hydrocarbon polymers from a previous oxide etch process, or redeposited material from a preclean sputter etch process. The native oxide and other defects create regions on the substrate which increases contact resistance.
The presence of native or process generated oxides and other defects may increase the via/contact resistance. Although defects may be limited to a thin boundary region within the features, even a thin boundary region can form a substantial part of small feature(s). The acceptable level of defects in the features decreases as the features get smaller in width.
Substrate processing systems, such as plasma preclean chambers utilizing resonator inductor circuits, may be used to clean a substrate before or after other processes. However, the inventors have observed that current fixed position resonator inductor circuits can only be tuned to a single position for a given configuration.
Accordingly, the inventors have provided embodiments of an improved substrate processing system.