Particle Removal from Si Substrates in Organic Solvents using Megasonic Energy

In this paper, particle removal experiments from silicon wafers in organic solvent using megasonic energy are presented. Nanoparticles are first deposited on Si wafers via controlled-contamination process. The particle removal efficiency as a function of megasonic power is studied both for freshly-deposited and aged particles. Several cleaning recipes are evaluated, by changing the processing conditions and rinsing time/chemistry. When low megasonic power is used, particles are found to cluster and re-deposit on the wafer surface after being detached. This phenomenon could be explained by charging phenomena of particles and silicon surfaces in the specific solvent. A surfactant is added to prevent clustering and re-deposition, leading to a noticeably improvement in particle removal efficiency.