Copper chemical mechanical polishing method

The invention discloses a copper chemical mechanical polishing method so as to remove copper residue which is hard to clean in a metal-dielectric medium-metal (MIM) structure. The method comprises the following steps: firstly, putting a wafer with the MIM structure on a first grinding pad for rough grinding to remove most copper on the surface; secondly, putting the wafer on a second grinding pad for finish grinding to remove residual copper on the surface of the wafer; thirdly, putting the wafer on a third grinding pad for grinding to remove residues of a barrier layer on the surface of the wafer, and reducing the height difference of a deep step; fourthly, putting the wafer on the first grinding pad and/or the second grinding pad once again for grinding to remove copper residues on the bottom of the deep step; and finally, putting the wafer on the third grinding pad for final flattening. The method can effectively clean the copper residues in a specific area in the MIM structure, and can remarkably reduce t