Scaling of gate length below 14nm has a lot of advantages such as high speed with low power consumption in device aspects. However, process requirement also becomes much tighter and defect control becomes the key to the yield enhancement. Every single surface particle can be potential killer defect depending on the particle location and process step. To remove large slurry particle to help following wet cleaning efficiency, in-situ cleaning modules such as brush scrubber cleaning and megasonic tank are implemented in most CMP equipment. However, due to device complexity, limitation of post CMP clean chemical and insufficient wet cleaning at post CMP step, fabrication process strongly relies on CMP in-situ cleaning for the clean surface. This study focuses on the brush cleaning performance and its optimization for sub-14nm device manufacturing. The experimental results show how brush scrubber cleaning optimization is achieved, and address effective process sequence to minimize cross contamination and to maximize particle removal efficiency. Challenges and requirements of brush manufacturing are also presented.