The Dependence of Material Removal Rate on Annealing Treatment in Polysilicon CMP

Chemical mechanical polishing (CMP) of polysilicon (poly-Si) films is an essential process in fabricating integrated circuit (IC) devices for high-performance dynamic random access memory (DRAM) and microelectromechanical systems (MEMS) with multi-level structures.Poly-Si films can have changes in surface roughness and grain boundary density (or Young's modulus) through thermal annealing treatment, which exerts a strong influence on poly-Si polishing performance (i.e., uniformity).Here, poly-Si films, after annealing for half hour at 1,050°C under nitrogen atmosphere, are polished to characterize the effect of annealing treatment on their material removal rate (MRR).The dependence of the surface roughness, grain boundary density, and Young's modulus of poly-Si films on annealing treatment is also intensively discussed.The results from this study will help us to establish optimal conditions for poly-Si CMP process.