Particle reduction in back end of line plasma-etching process: CFM: Contamination free manufacturing
Particle contamination within a plasma-etching chamber causes tool down time in semiconductor manufacturing. The purpose of this work is to investigate the sources of contamination and find an effective solution for Back End of Line (BEOL) processes and improve tool up time. Despite typical maintenance, such as cycling chamber, wiping Electric Static Chuck (ESC) components and replacing chamber consumable parts, particle contamination issue persisted. Contamination analysis and ESC examination suggested etch byproduct redeposition during chuck discharge step as root cause. Modifying the discharge step was found to reduce the particle failure rate from 50% to 7%. This significant improvement confirms redeposition on ESC during discharge step and particle resuspension from ESC surface is the primary source for the particle contamination issue.