Clean room Airborne Molecular Contamination (AMC) on damascene Cu interconnects

Spansion's facility in Austin, Texas USA has proactively been updating the older AI technology fab with state-of-the-art control systems, as driven by rapid response to exposed Cu experiences from the latest in Cu technology. This paper discuss the positive and negative in-line and material observations with processing Cu in open cassettes; the manufacturing operations queue time affects; along with process/tool experiments and factory windowing performed to address systematic yield loss issues. The results support the requirements to protect the exposed Cu from the atmospheric environment and to encapsulate the polished Cu in dielectric as rapidly as possible. Additionally, the results suggest that common fab gaseous chemical elements and molecules containing Sulfur (S), Chlorine (CI
₂
) and organics (CH
_x
) from a variety of typical fab and external sources have significant impacts on the exposed Cu after the damascene oxide etch, Cu seed, Cu ECD plating and Cu CMP operations. Recommendations are suggested to quantify, control and measure the fab atmospheric contaminates on exposed copper to maximize fab and wafer yields while improving the Cu BEOL integrated reliability.