Improvement of TEOS-chemical mechanical polishing performance by control of slurry temperature

Effects of slurry temperature on the chemical mechanical polishing (CMP) performance of tetra-ethyl ortho-silicate (TEOS) film with silica and ceria slurries were investigated. The change of slurry properties as a function of different slurry temperatures was also studied to obtain higher removal rates and smoother surface morphology. The changes observed with increasing temperature are as follows: the pH showed a slight tendency to decrease, the conductivity of the slurry showed a tendency to increase, the particle size in the slurry decreased, and the zeta potential of the slurry decreased with temperature. The removal rates linearly increased and maintained at the temperature of about 40 °C. The hydroxyl (OH⁻) groups increased in the slurry as the slurry temperature increased and then they diffused into the TEOS film. The surface of the TEOS film became hydro-carbonated by the diffused hydroxyl groups. The hydro-carbonated surface of TEOS film could be removed more easily. Better surface morphology of TEOS films could be obtained at 40 °C of silica slurry and at 90 °C of ceria slurry. It is found that the CMP performance of TEOS film could be significantly improved or controlled by change of slurry temperature with the same slurry.