Striking a balance: Role of supramolecular assemblies on the modulation of the chemical and mechanical contributions during Post-STI CMP cleaning

Understanding the chemical and mechanical components of supramolecular cleaning chemistries for post-STI CMP cleaning is paramount in reducing defectivity for the continued miniaturization of advanced technologies. Therefore, macroscopic cleaning performance metrics can be correlated to critical non-covalent interactions probed at the molecular scale and provide insight into the kinetic equilibrium that drives encapsulation for optimal cleaning. The adsorptive properties of these cleaning chemistries can be directly related to their cleaning performance, in both particle removal and scratch induction. Results indicate that while spherical supramolecular structures (i.e. micelles/vesicles) improve particle removal, they have a slower rate of adsorption to the contaminated surface and yield increased shear force at the wafer surface inducing a greater number of post-CMP scratches. On the other hand, non-spherical structures (i.e. polyelectrolytes) create a lubrication barrier that disrupts the shear force at the wafer surface resulting in lower particle removal efficiency albeit at lower scratch counts. The synergistic balance of chemical and mechanical attributes can be modulated to achieve optimal cleaning performance under reduced shear force.