Predictive, Short-Interval Scheduling Improves Litho Utilization and Cycle Time
There is a strong need to use optimization systems and processes to better match lots and tools, especially in photolithography which is a known bottleneck area. Keeping litho tools fully utilized and reducing wafer cycle time is key to meeting on-time customer delivery. These benefits are realized by repeatedly creating new litho schedules based on the changing state of the fab. Prediction provides a snapshot of the future, allowing better lot grouping and increased tool utilization.
The Applied SmartSched integrates real-time dispatching (RTD) policies with locally optimized short-interval schedules to increase fab throughput and optimize litho tool utilization by converting ‘white space’ to available capacity. In essence, it produces an optimized schedule every few minutes that is executed by the RTD system. Its predictive techniques determine, for example, precisely where work-in-process (WIP) and reticles will be to efficiently process the WIP just in time. This breakthrough technology is now being deployed in lithography modules of production fabs; initial results show over 2% increase in litho wafers out and litho tool utilization improvements of1%.
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