Discrete Event Simulation (DES) in semiconductor manufacturing is a simulation methodology that models fab operations as a sequence of events occurring at discrete time points — processing arrivals, tool completions, breakdowns, and lot dispatching to predict cycle time, throughput, and tool utilization.

Key DES Components

• Events: Lot arrival, process start, process end, tool breakdown, PM start/end.
• Queues: Lots waiting at each tool group with dispatching priority rules.
• Resources: Tools (with availability, PM schedules), operators, transport vehicles.
• Statistics: Collect cycle time, WIP, utilization, queue time distributions during simulation.

Why It Matters

• Capacity Planning: Determine how many tools are needed for a target throughput and cycle time.
• What-If: Test the impact of tool additions, recipe changes, or product mix changes before implementation.
• Industry Standard: Tools like Applied Materials AutoSched, Rockwell Arena, and AnyLogic are widely used in fab planning.

DES is fast-forwarding through the fab — simulating months of factory operations in minutes to optimize capacity, scheduling, and throughput.