Synthesis of non-rigid coreshell structured PS/SiO2 composite abrasives and their oxide CMP performance
The positively charged PS microspheres were prepared via soap-free emulsion polymerization method by using azobisisobutyronitrile (AIBN) as initiator. Tetraethylorthosilicate (TEOS) hydrolysis catalyzed and the negatively charged SiO2 could be absorbed onto the surfaces of the positively charged PS microspheres. The microstructures of the composites were characterized by scanning electron microscope (SEM), transmission electron microscope (TEM), fourier transform infrared spectrum (FT-IR), and X-ray diffraction (XRD). The composites were collocated into polishing slurries for the chemical mechanical polishing (CMP) of silicon dioxide dielectric layer. The dielectric layers were investigated by atomic force microscope (AFM). The results indicated that the particle size of composites is about 550nm, and the PS microsphere is uniformly coated by SiO2 shell (about 20nm in thickness). After CMP, the composite abrasives led to lower topographical variations and surface roughness, compared with pure SiO2 abrasives and PS microspheres. The root mean square (RMS) value within 55?m area of dielectric layer polished by PS/SiO2 composite abrasives is 0.209nm, and the material removal rate (MRR) can reach 367.148.0nm/min.
coreshell structure ps/sio2 composite abrasives chemical mechanical polishing (cmp)