Electroplanarization of large and small damascene features using diffusion barriers and electropolishing

摘要

A disclosed electroplanarization process involves "masking" certain regions of a wafer surface during electropolishing. The regions chosen for masking are features of relatively low aspect ratio (i.e., features that are wider than they are deep). The masking is accomplished with a material of relatively low ionic conductivity, which effectively slows or blocks transport of the metal ions produced during electropolishing. Examples of masking materials include concentrated phosphoric acid and certain polymers.