Principal Investigator Jung-Hoon Chun
Co-investigator Nannaji Saka
This research establishes a theoretical framework to relate the process parameters to the different wafer/pad contact modes to study the behavior of wafer-scale polishing. Several models of polishing - microcutting, brittle fracture, surface melting and burnishing - are reviewed. Blanket wafers coated with a wide range of materials are polished to verify the models. Plastic deformation is identified as the dominant mechanism of material removal in fine abrasive polishing. 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. Experiments study the effects of pattern geometry on the rates of pattern planarization, oxide overpolishing and Cu dishing.