Copper Residue Removal from Electrostatic Chuck to Mitigate Helium Leak Faults Using Enhanced In-Situ Chamber Clean : EO: Equipment Optimization

In traditional CMOS, Copper (Cu) and Aluminum (Al-0.5%Cu) are predominantly used for back-end-of-line (BEOL) interconnects and Metal Cap, Cu is used widely for interconnect wiring due to its superior electrical properties and better scalability, however Aluminum (Al-0.5%Cu) is preferred choice for Metal cap layer commonly known as the bond pad due to its cost-effectiveness and better wire bonding compatibilities. The formation of Metal cap is carried out in plasma dry aluminum etch tools. These dry etch processing chambers are susceptible to higher helium leak faults due to Cu contamination, primarily Cu residues on the electrostatic chuck (ESC) induced by wafer backside. This paper investigates effective mitigation strategies for helium leak faults by employing in-situ chamber cleaning techniques to remove Cu residues from the ESC surface. The proposed method of in-situ chamber cleaning aims to maintain the cleanliness of the etch chamber and ESC, hence reducing helium leak incidents and maintaining process stability