Effect of heat according to wafer size on the removal rate and profile in CMP process

The effect of wafer size on the removal rate and profile during chemical mechanical polishing was investigated with two representative thin films: SiO2 and Cu, which were used as the dielectric and interconnection, respectively. Experiments were conducted using SiO2 and Cu blanket wafers with 100, 200, and 300 mm diameters, while the results for 450 mm diameter wafers were estimated using geometric calculation. The experimental results showed that the heat generated by an increase in the wafer size affects the removal rate and the Within-Wafer Non-uniformity (WIWNU). In particular, the polishing temperature is one of the most important factors affecting the removal rate and profile in the Cu CMP process. An optimum slurry flow rate may exist for each wafer size, which should be carefully considered, particularly when using 450 mm diameter wafers in the semiconductor industry.