Characterization of scratches generated by a multiplaten copper chemical-mechanical polishing process

Copper (Cu) chemical-mechanical polishing (CMP) using a multiplaten approach is a key process in the fabrication of Cu interconnects. It is customary to employ different slurries on each platen in a bid to optimize the performance of the Cu CMP process. These slurries generally contain abrasive particles that aid in the removal of material during CMP, but their presence is likely to result in the formation of scratches. In this article, a defect source analysis (DSA) technique was employed to identify the different types of scratches that were generated progressively by the three platens of an Applied Materials Mirra CMP polisher. In addition, the DSA technique also allowed tracking of the scratches from one platen to the next. Our results showed that scratches due to platen 1 were likely to result in more damage, and this was attributed to the use of alumina abrasive particles on platen 1. (C) 2004 American Vacuum Society.