Post-CMP Cleaning of Copper/Hydrophobic Low-k Dielectric Films

The requirements for copper post-CMP cleaning include slurry particle removal, organic residue removal, metal contamination reduction, water mark elimination, copper corrosion prevention, and low-k surface change minimization. The difficulty in meeting some of these requirements varies with the CMP consumables (e.g. slurry, pad, etc.) used. Over the past ten years, the most significant factor driving changes in copper post-CMP cleaning is low-k surface hydrophobicity. A highly hydrophobic ultra low-k surface provides a significant challenge not only to wafer drying, but also to wafer cleaning and rinsing. In this paper, state-of-the-art post-CMP cleaning of Cu/ultra low-k dielectric films is presented.