Doped polysilicon is used as a via fill material for through silicon via technology. Boron doping is used to reduce the polysilicon resistivity but boron doping significantly decreases the polish removal rate. Here the influence of slurry characteristics, chemistry and abrasive properties, on the chemical mechanical polishing of heavily boron-doped polysilicon is investigated. The effect of slurry pH on silica abrasive size and colloidal stability is examined as well as the influence of these effects on the polish rate. The optimum abrasive concentration is similar to 6 wt% and higher concentrations did not improve the polish rate due to the saturation of slurry particles on the wafer surface. Smaller abrasive particles, with 10 times higher surface area per unit weight improved the polish rate similar to 20%. Finally, polish conditions with mechanical and chemical dominance are compared. (C) 2016 The Electrochemical Society. All rights reserved.
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