CMP of a Ru based layer in an advanced Cu low-k stack

Inhalt:
Ruthenium based layers are promising candidates as novel barrier and seed alloys for future technology nodes. This contribution presents CMP results on such a layer, provided by Applied Materials, integrated in an advanced copper low-k stack patterned with a metal hard mask based process. Results on the effect of barrier and metal hard mask polishing with different slurries on the final planarity and on the electrical properties of Cu structures are presented. Some limiting factors from a CMP point of view with respect to feature size and pattern density have been identified.