A Study on Polymer Dispersants in CMP Ceria Slurry for the Polysilicon Film Removal Suppression

CMP (Chemical Mechanical Polishing) is essential for achieving the desired surface quality and planarity required for subsequent layers and processing steps in semiconductor manufacturing. However, the aggregation of slurry particles caused by abrasive materials can lead to scratches, defects, and increased surface roughness, degrading the quality and durability of the finished surface during the CMP process. In this study, ceria slurry was prepared using an anionic polymer dispersant with an ammonium salt of an acrylate copolymer (AAPD) at different contents of 2.5, 3.0, 5.0, and 7.0 wt.% to minimize particle aggregation and to evaluate the polysilicon (Poly-Si) film removal suppression functionality commonly required in CMP processes. The CMP evaluation revealed that the HDP MRR (material removal rate) ranged from 580 to 660 Å/min at 60 s, while the Poly-Si MRR was significantly lower at 62 to 71 Å/min, confirming the existence of Poly-Si film removal suppression behavior. The substantially reduced Poly-Si MRR suggests that AAPD may contribute to polymer-mediated suppression of Poly-Si removal, although the specific inhibition mechanism remains to be clarified. This suggests that the AAPD enables the formulation of a one-component ceria slurry with effective Poly-Si film removal suppression capability for semiconductor CMP applications.