Monitoring of multi-patterning processes in production environment

Multi-patterning processes have become common in the leading-edge semiconductor industry. These processes require a good patterning uniformity over the wafer while different process steps have impact. The initial lithography steps can be nearly perfect, but the CD variation after a trim process may cause CD variation after the spacer deposition. In fact, that leads to final non-uniformity of the final CD. Monitoring and controlling the individual CD parameters is not sufficient to ensure a stable process. We define a set of new KPIs, taking all contributions into account and using macro measurement data. We show that a reliable monitoring is achieved to meet the process specifications.