Lam Research Corporation

Matthew A Rigsby

Jonathan David Reid

Natalia V Doubina

Lee J Brogan

Embodiments herein relate to methods, apparatus, and systems for electroplating metal into recessed features using a superconformal fill mechanism that provides relatively faster plating within a feature and relatively slower plating in the field region. Moreover, within the feature, plating occurs faster toward the bottom of the feature compared to the top of the feature. The result is that the feature is filled with metal from the bottom upwards, resulting in a high quality fill without the formation of seams or voids, defects that are likely where a conformal fill mechanism is used. The superconformal fill mechanism relies on the presence of a sacrificial oxidant molecule that is used to develop a differential current efficiency within the feature compared to the field region. Various plating conditions are balanced against one another to ensure that the feature fills from the bottom upwards. No organic plating additives are necessary, though plating additives can be used to improve the process.

Process for optimizing cobalt electrofill using sacrificial oxidants

Various embodiments herein relate to methods and apparatus for electroplating cobalt on a substrate. In many cases, the cobalt is electroplated into recessed features. The recessed features may include a seed layer such as a cobalt seed layer. Electroplating may occur through a bottom-up mechanism. The bottom-up mechanism may be achieved by using particular additives (e.g., accelerator and suppressor), which may be present in the electrolyte at particular concentrations. Further, leveler, wetting agent, and/or brightening agents may be used to promote high quality plating results. In various embodiments, the substrate is pre-treated to remove oxide (and in some cases carbon impurities) from the seed layer before electroplating takes place. Further, the electrolyte may have a particular conductivity to promote uniform plating results across the face of the substrate.

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Tualatin, OR, United States of America

Matthew A Rigsby