METHOD FOR IMPROVING UNIFORMITY OF CHEMICAL MECHANICAL PLANARIZATION PROCESS FOR METAL PLUG IN POST-GATE PROCESS

摘要

A method for improving uniformity of a chemical mechanical planarization (CMP) process for a metal plug in a post-gate process is provided. The method comprises: before performing the CMP process for forming the metal plug, the height difference between a metal layer (4) in a through-hole region (3) and a metal layer (4) in a non-through-hole region is greatly reduced by a one-step metal etching process, thus the smaller height difference has a little influence on the subsequent CMP process, and during the polishing, the height difference can't be transferred to the metal plug formed subsequently, the recess in the top of the metal plug can be greatly reduced, the metal plug (6) with a planar top can be obtained, and the electrical performance and yield of the device can be improved.