슬러리 유동의 화학적이고 기계적인 평탄화에 대한 실험과 수치유동해석(CMP)

Abstract

In this study slurry flow field in Chemical Mechanical Polishing (CMP) process was analyzed by numerical simulations and by particle image velocimetry (PIV). PIV measurement for hydrodynamic regime of CMP is novel approach, and this is first study that combines both numerical simulations and experimental measurements under one umbrella. Quality of CMP in semiconductor production is characterized by its output properties such as removal rate (RR) and non-uniformity (NU). Non-uniformity of wafer surface is due to the irregularity of material removal rate across the wafer surface, and both NU and RR problem is deeply rooted in the uneven slurry flow distribution and shearing stresses on the wafer surface. The slurry flow field was studied at wafer scale under various pad and carrier rpm’s conditions. This is the work to provide an insight into the non-uniformity and removal rate based on slurry flow and shear rate analysis. Direct measurement of slurry flow field is also applied to CMP process by adequately modifying conventional PIV system. A three-dimensional fluid dynamics simulation for chemical mechanical planarization (CMP) processes is presented. Numerical simulation is carried out for the current analysis and for future extensive usage to predict the characteristics of removal rate and nonuniformity under various CMP conditions particular in those hard pad materials. The analysis shows that the flow speed and shear stress rate is strongly influenced by pad velocity and the overall flow field is characterized mainly by the ratio between the Pad and Carrier ratios.