Mechanics, Mechanisms, and Modeling of the Chemical Mechanical Polishing Process

Download or read book Mechanics, Mechanisms, and Modeling of the Chemical Mechanical Polishing Process written by Jiun-Yu Lai and published by . This book was released on 2001 with total page 616 pages. Available in PDF, EPUB and Kindle. Book excerpt: (Cont.) Additionally, contact mechanics models, which relate the pressure distribution to the pattern geometry and pad elastic properties, explain the die-scale variation of material removal rate (MRR) on pattern geometry. The pad displacement into low features of submicron lines is less than 0.1 nm. Hence the applied load is only carried by the high features, and the pressure on high features increases with the area fraction of interconnects. Experiments study the effects of pattern geometry on the rates of pattern planarization, oxide overpolishing and Cu dishing. It was observed that Cu dishing of submicron features is less than 20 nm and contributes less to surface non-uniformity than does oxide overpolishing. Finally, a novel in situ detection technique, based on the change of the reflectance of the patterned surface at different polishing stages, is developed to detect the process endpoint and minimize overpolishing. Models that employ light scattering theory and statistical treatment correlate the sampled reflectance with the surface topography and Cu area fraction for detecting the process regime and endpoint. The experimental results agree well with the endpoint detection schemes predicted by the models.