A method and apparatus for chemical delivery through the brush (240) used in semiconductor substrate cleaning processes. The chemical solutions (210, 220) are delivered to the core (230) of a brush (240) where the solution is absorbed by the brush (240) and then applied by the brush (240) onto the substrate. This delivery system applies the chemical solutions (210, 220) uniformly to the semiconductor substrate, reduces the volumes of chemical solutions (210, 220) used in a scrubbing process, and helps maintain control of the pH profile of a subtrate. This system is described and illustrated in the manner it is used in conjunction with a scrubber that scrubs both sides of a semiconductor substrate.