Chemical mechanical polishing of PZT thin films for FRAM applications

In this paper, we first applied the chemical mechanical polishing (CMP) process to the planarization of PZT film in order to obtain a good planarity of the ferroelectric film surface. Pb1.1(Zr0.52Ti0.48)O3 (shortly PZT) ferroelectric film was fabricated by the sol–gel method. And then, we compared the structural characteristics before and after CMP process of PZT films. Their dependence on slurry composition and pH change was also investigated. Removal rate, within-wafer non-uniformity (WIWNU%) and surface roughness have been found to depend on slurry abrasive types and their hardness, especially, surface roughness and planarity strongly depend on its pH value.