Abstract: A cleaning method for a wafer is provided. First, a first cleaning process is performed wherein the first cleaning process includes providing a cleaning solution having a first concentration. Next, a second cleaning process is performed, wherein the second cleaning process includes providing the cleaning solution having a second concentration. The second concentration is substantially greater than the first concentration. Next, a post-cleaning process is performed to provide dilute water.

Abstract: A method for cleaning a surface is disclosed. First, a substrate including Cu and a barrier layer is provided. Second, a first chemical mechanical polishing procedure is performed on the substrate. Then, a second chemical mechanical polishing procedure is performed on the barrier layer. The second chemical mechanical polishing procedure includes performing a main chemical mechanical polishing procedure to partially remove the barrier layer and performing a chemical buffing procedure on the substrate using a chemical solution which has a pH value of about 6 to about 8 to remove residues on the substrate after the main chemical mechanical polishing procedure. Later, a water rinsing procedure is performed on the substrate. Afterwards, a post clean procedure is performed on the substrate after the second chemical mechanical polishing procedure.