Dispersal mechanism of different dispersants and its effect on performance of 4H-SiC polishing slurry

Chemical mechanical polishing (CMP) offers promising pathway to smooth 4H-SiC. Dispersion stability of polishing slurry is crucial factor affecting 4H-SiC performance. Particles in polishing slurry can easily agglomerate due to poor dispersion stability, affecting surface quality of wafers. Nano-Al 2 O 3 is common particle in the slurry that directly controls mechanical removal. In this paper, the impact of different dispersants (PEG, (NaPO 3 ) 6 , and NH 4 PAA) on the dispersibility of slurry containing nano-Al 2 O 3 is studied. Results indicate that the slurry containing NH 4 PAA exhibits the greatest dispersion stability with superior 4H-SiC surface quality, with surface roughness (Sa) reaching 1.054 nm. The slurry containing PEG shows poor dispersion, leading to poor SiC surface quality, and the Sa reached 5.314 nm. The dispersion mechanism of different dispersants is also discussed.