Temperature effects of pad conditioning process on oxide CMP: Polishing pad, slurry characteristics, and surface reactions

Temperature effects were investigated on the improvement of silicon dioxide (oxide) chemical mechanical polishing performances including removal rate and surface morphology by controlling the pad conditioning temperature. The characteristics of silica slurry including potential of hydrogen (pH), conductivity, particle size, and zeta potential were changed by the frictional heat of the polishing process and the remaining heat after a high-temperature pad conditioning process. These changed slurry properties made the oxide surface hydro-carbonate to be removed easily. The slurry residues in pores and grooves of the polishing pad were also clearly removed by the high-temperature pad conditioning process. These clear pores and enlarged grooves made the slurry attack the oxide surface. The planarity of the oxide film was improved by the use of a little softened pad after the high-temperature pad conditioning process.