Development of “Soft” Cleaning Chemistries for Enhanced STI Post-CMP Cleaning

Abstract

With the rapid miniaturization of advanced technologies, limiting device defects has become of utmost importance in maintaining high performing integrated circuits. Shallow trench isolation (STI) chemical mechanical planarization (CMP) uses a synergistic balance of ceria (CeO2) nanoparticles and functional chemistry to modulate surface adsorption interactions necessary to remove excess topography. This work aims to develop a post-CMP cleaning chemistry that enhances nanoparticle removal via “soft” encapsulation by employing a polyelectrolyte/surfactant (PES) matrix. A surface adsorbing/charge flipping encapsulation process is proposed as a vehicle to remove slurry contamination at low friction. Investigation into the synergy between slurry chemistry and PES cleaning chemistry, with respect to defect aggregate formation, was correlated to the cleaning efficiency as well as friction. Using a suite of techniques to study the real-time defect aggregate formation mechanism it was determined that the supramolecular structure is critical to balance defect forming events with enhanced cleaning efficiency.