TECHNIQUE FOR UNIFORM CMP

摘要

Pitch-dependent dishing and erosion following CMP treatment of copper features is quantitatively assessed by atomic force microscopy (AFM) and transmission electron microscopy (TEM). A new sequence of processing steps presented herein is used to prevent dishing and to reduce significantly the local pitch- and pattern density-induced CMP non-uniformity for copper metal lines having widths and spacing in the range of about 32-128 nm. The new process includes a partial copper deposition step followed by deposition of a silicon carbide/nitride (SiCxNy) blocking layer. A multi-step CMP process planarizes areas of the resulting irregular surface that have narrow features, while the blocking layer protects areas that have wide features.