A chemical mechanical polishing (CMP) apparatus includes a process controller operable to execute a multi-step CMP algorithm implementing delivering a first chemical composition onto the wafer surface while on a platen for a first time duration, and without removing the wafer from the platen, delivering a second chemical composition different from the first chemical composition onto the wafer surface for a second time duration. CMP is performed with a polishing pad contacting the wafer surface using a slurry including the first chemical composition during the first time duration or the second chemical composition during the second time duration, and a non-polishing process without any contact of the polishing pad to the wafer surface using the other of the first and second chemical composition during the other of the time durations, and repeating the multi-step CMP comprising process a plurality of times on the wafer.