Self-stopping slurry for planarizing extremely high surface film topography in nanoscale semiconductor devices

In this study, a novel chemical–mechanical planarization (CMP) slurry that can perform self-stop polishing was designed. The essential aspects for self-stop polishing are precise design of a nonionic polymer type, molecular weight, and molecular concentration of a self-stopping chemical agent. A good example is polyvinylpyrrolidone (PVP) with a molecular weight of 1300 k and molecular concentration of 0.3 wt%. In this chemical design, the adsorption of a polymer hindrance layer on the surface film topography during CMP can become sufficient under self-stop conditions such as a specific polishing time (e.g., 4 min). The self-stop polishing mechanism is associated with the presence of a relative local pressure difference on the surface film topography. The proper adsorption of the polymer hindrance layer on the surface topography can achieve a uniform relative local pressure distribution globally, and the film polishing rate can achieve adequate planarization of the surface film topography.