A method of wafer reclaim, at least includes: provide a wafer; perform a first semiconductor process to let both film layer and numerous particles are formed on the wafer; perform chemical mechanical polishing process to let part of film layer is removed and scales of part of particles are decreased; perform wet etching process to let both residual film layer and residual particles are further removed; perform cleaning process to let surface of wafer is cleaned; and perform second semiconductor process to let a semiconductor structure is formed on wafer. Furthermore, concepts of the invention that both film layer and particles are thoroughly removed by both chemical mechanical polishing process and wet etching process can be applied as a method for cleaning wafer and a method for planarizing wafer.