Ultra-High Removal Rate Copper CMP Slurry Development for 3D Application

Abstract

Chemical-mechanical planarization (CMP) has been widely accepted in IC manufacturing. With technology moves to 45 nm and beyond, the challenge of continuous reduction of interconnect features resulting in the increased Cu line resistivity. To mitigate this effect 3-D packaging where through-silicon vias (TSV) are filled with electroplated Cu can be used. A moderately high removal rate slurry, ER9200 was developed and the work was presented elsewhere (ICPT Taiwan Conference Nov. 2008). However certain 3D structures have very thick Cu overburden. For such structures ultra high removal rates of 4~5 µm/min may be needed. This process requires a high speed Cu CMP process to remove the thick overburden Cu layer. Presented herein is a Cu CMP slurry with ultra-high removal rate, yet good Planarization Efficiency and low defects. This new colloidal silica based developmental slurry achieves much higher removal rate, and is suitable for Cu 3D CMP application.