Visualized characterization of slurry film between wafer and pad during chemical mechanical planarization

Chemical mechanical planarization (CMP) has emerged recently as an indispensable processing technique for planarization in submicrometer multilevel very large scale integration (VLSI). The demand from industry for fast material removal and a high degree of uniformity has been a serious challenge for the advancement of this key technology. Among various process aspects, the slurry flow between wafer and pad plays an important role in the pursuit of these goals. This study provides a visualized characterization of the amount and distribution of the fluid film between the wafer and pad. The fluid film is analyzed by the digital picture obtained through the transparent carrier and dyed fluid. The effects of process parameters are extensively investigated, including platen and carrier speed, pad design, rinsing location, and flow rate of slurry and wafer size. Suggestions for process recipes aiming at fast and uniform CMP are drawn based on the current results.