Novel CuCMP Slurry Evaluation for 45/40nm BEOL Low-k Technology and Beyond

摘要

Novel CuCMP slurry was evaluated under different polishing conditions and its impact on topography, thickness and in line test performance was investigated. Generally, topography, such as dishing and erosion, results from over-polishing after Cu polishing step and it can be modified and reduced by fine tuning process parameters. Firstly, different Cu polishing condition has been attempted to produce different topography for barrier polishing to compensate in order to cater for different integration scheme with different oxide material. Secondly, topography can be modified by barrier polishing condition due to high selectivity slurry is used during barrier polishing. Longer polishing time can cause Cu protruded in narrow dense arrays. Electrical data shows Cu polishing overpolishing time has impact on Rs, and longer overpolishing results in higher Rs, as well as high head/platen rotation speed.