CMP metal polishing slurry and process with reduced solids concentration

Abstract

This disclosure describes a low particle concentration formulation for slurry which is particularly useful in continuous CMP polishing of copper layers during semiconductor wafer manufacture. The slurry is characterized by particle concentrations generally less than 2 wt %, and advantageously less than 1 wt %. In particular embodiments, where the particle concentration is in a range of 50 to 450 PPM, an 8-fold increase in polishing rate over reactive liquid slurries has been realized. Slurries thus formulated also achieve a reduction in defectivity and in the variations in planarity from wafer to wafer during manufacture, by improving the stability of polishing quality. The slurry formulations permit substantial cost savings over traditional 2-component, reactive liquid and fixed/bonded abrasive slurries. In addition the formulations provides an advantageous way during CMP to easily change the selectivity or rate of removal of one film material vs. another. Yet another use is to provide slurry “pulsing” as a means to activate bonded abrasive or fixed abrasive slurry technology.

Dependencies are inferred from the claim text.