Optimizing robot algorithms with simulation

Maximizing equipment throughput on multi-chambered cluster tools is an ongoing objective for semiconductor fabs. The increasing use of dual-armed robots and the need to process multiple products simultaneously complicates this objective. Typically, when a new processing technology is introduced, one chamber inside the tool is dedicated to the new process, while the other chambers are assigned to run normal production wafers. This results in multiple wafer flows or "parallel routes" within the tool. Determining and implementing optimal robot schedulers to efficiently handle the complexities within the tool is key to maximizing equipment throughput. This paper introduces the components of a multi-chambered cluster tool and discusses how simulation was used at Infineon to develop, test, and optimize efficient wafer selection rules. Several real-world cases are detailed and reported.