Manufacture method for improving W-CMP rear-surface flatness

The invention discloses a manufacture method for improving W-CMP (Wolframium-Chemical Mechanical Polishing) rear-surface flatness. The photoetching and etching technology is carried out twice to form contact holes and redundant patterns; the depths of the redundant patterns are smaller than those of the contact holes, and then a wolframium metal layer is formed; and the W-CMP technology is adopted to remove the wolframium metal layer on a front metal insulating medium layer, so as to form wolframium metal contact layers in the contact holes and redundant metal layers in the redundant patterns. Therefore, adverse effects on the device characteristics are caused because the redundant metal layers are connected with gate electrodes and metal silicide in the active region; interposition of the redundant patterns is utilized to reduce metal density contrast among all regions; the W-CMP rear-surface flatness is improved; and metal residues and defects generated during follow-up copper interconnection are avoided.