Double-sided brush scrubbing has become a dominant method for post-CMP cleaning applications. Chemicals delivered in-situ with brush scrubbing greatly enhance the cleaning capabilities. In this paper, the effect of dilute HF on reducing particulate defects and trace metal contamination on polished oxide surface is studied using a HF-compatible double-sided scrubber. AFM data on the interaction of dilute HF with oxide / tungsten plug array after tungsten CMP is also presented. Scrubbing with dilute HF is shown to be highly effective is removing slurry agglomerates that strongly adhere to the post-CMP oxide film.