Method of CMP of polysilicon
An improved and new process for fabricating a planarized structure of polysilicon plugs embedded in silicon oxide has been developed. The planarizing method comprises a two-step CMP process in which the first CMP step comprises chemical-mechanical polishing using a first polishing slurry which is selective to polysilicon and the second CMP step comprises chemical-mechanical polishing using a second polishing slurry which polishes both polysilicon and silicon oxide. The processing time of the two-step CMP process is significantly less than the processing time of a one-step CMP process requiring an over-polish period. This reduced processing time reduces the cost of the CMP operation and at the same time produces a product with superior planarity and without reliability degradation due to residues of polysilicon.
Taiwan Semiconductor Manufacturing Company
Y C H
Y10S C09G H01L
additional inventional inventional
Chung-Long Syun-Ming
Chang Jang