Integration of Atomic Layer Deposition-Grown Copper Seed Layers for Cu Electroplating Applications

A plasma-enhanced atomic layer deposition (PEALD) copper process, using Cu(II) acetylacetonate and atomic hydrogen, was developed for Cu seed applications in nanoscale semiconductor processing. In this paper, the integration characteristics of PEALD Cu with electroplated Cu for advanced interconnect applications were investigated. Superconformal electroplated [electrochemical deposition (ECD)] copper was demonstrated on PEALD Cu-seeded high aspect ratio patterned structures. The filling characteristics of ECD/PEALD-grown Cu were compared with those of a conventional ECD/physical vapor deposition (PVD)-grown Cu stack. Void-free electroplated Cu was demonstrated on 60 and 35 nm patterned via structures using both atomic layer deposition Ru/TaN and conventional PVD Ta/TaN liner/barrier structures coupled with PEALD Cu seed layers. The resulting integration characteristics suggest that electroplated/PEALD Cu is a promising integration approach for emerging complementary metal oxide semiconductor metallization applications.