Clarkson University Department of Chemical and Biomolecular Engineering Seminar
Investigating Ceria-Related Defects on SiO2 Films from Nanoparticle Remnants and Tribofilms
Van-Tuan Nguyen
Abstract
As semiconductor devices shrink in size, achieving ultra-smooth surfaces becomes increasingly important. The fabrication of advanced devices demands stringent conditions to minimize defects, with one potential source being ceria defects on SiO2 films during CMP using ceria-based slurry. These defects can lead to device failure and compromised reliability. Despite advancements in removing ceria defects, new issues emerge as detection technologies improve, now identifying features as small as 45 nm. For instance, embedded ceria particles may not be fully removed, leaving bonded remnants on the SiO2 film.This study examines various ceria-related defects that can form during CMP and post-cleaning, including ceria remnants, small fragments, and Tribofilm. AFM phase images showed no traces of ceria remnants, indicating their removal during cleaning, but left dents in the SiO2 film ranging from a few nanometers to 45 nm in depth. The study also found that the depth of these dents is directly proportional to the polishing pressure. However, small ceria particle fragments, measuring 10 to 15 nm, were still detected on the SiO2 surface. These fragments, likely produced during polishing, exhibit strong adhesion to SiO2 and resist removal by brush scrubbing.
Additionally, the research identified a Tribofilm containing Ce atoms on the SiO2 surface, which formed through a chemical interaction between ceria particles and the film during polishing. SEM-EDX mapping confirmed the presence of Ce atoms in regions without visible ceria particles, validating the existence of the Tribofilm. These findings offer a deeper understanding of ceria-related defects in semiconductor manufacturing and provide valuable insights for improving residue removal and surface cleaning processes after CMP.
Monday, 04/21/2024 at 2:30 pm
CAMP 194
https://clarkson.zoom.us/j/95529580049
Van-Tuan Nguyen is currently a Ph.D. student in the Seo Lab at Clarkson University. He graduated from Vietnam National University and Chungnam National University with his B.E. and M.E. in Chemical Engineering in 2019 and 2022, respectively. His research areas focus on the post-CMP cleaning process and Scanning Probe Microscopy.