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FabSim offers a unique approach to simulate a semiconductor manufacturing plant with discrete-event simulation. As a compact tool in a single executable FabSim allows to simulate a complete fab very efficiently.
Data representing the fab and the planned operation are required as input. No extra effort is needed to set up a model. Machines are listed with their different recipes, batching capability, dispatching rules, setup and setup avoidance policies, MTBF and MTTR. Processes are described by their flow charts which contain a sequence of machines and recipes to be visited by each lot. The lots are started in a planned sequence (start time, process and priority). Alternatively a maximum WIP may be defined (CONWIP fab control). Variability may be introduced by MTBF, slightly variable process step duration, and variable waiting time for lot transport. The output is a list of lots leaving the fab after being processed. Other data like machine usage or buffer occupancy is available as well.
The fab model is set up dynamically at runtime. Up to 128 different toolsets may be used, each toolset may comprise of up to 50 identical machines (e.g. 15 steppers, 10 furnace tubes, up a total of 6400 pieces of equipment). The number of different process flows is not limited. Any process step sequence may be defined, up to 700 steps per flow.
Besides technical questions FabSim may determine economical data. The amount of personnel needed to run the fab is derived during a simulation run for operators, as well as for setup, maintenance and repair technicians and engineers. A complete but still efficient factory cost model is uner development and will be implemented soon.
The FabSim fact sheet (in pdf format, 36 kB) and FabSim data sheet (in pdf format, 24 kB) will give you more information. All details are described in the FabSim manual.
The simulation is very fast. As an example a pilot line with 42 different toolsets, about 60 pieces of equipment in total, has been set up. Lots are entered continuously. To simulate 140 days of operation FabSim will require less than 10 seconds on a PC (LINUX, 1.4 GHz). Simulation of a fully equipped fab with 500 waferstarts per day will need about 60 seconds. FabSim is written in C++ and may run on different OS. The simulation engine is proprietary. Some of it's basic ideas are derived from SystemC, a well maintained, open source class library made by Synopsis and others to create system on chip and system-level designs.
FabSim is currently available for the MS Windows operating systems as well as for LINUX.
FabSim Interactive contains the simulator inside a Windows dll. Interactive simulation is offered by access to dll functions to fully control the simulation process. The optimization of the number of machines per toolset for a given throughput is an example of interactive simulation control.
With its simple text file tables as input and fast execution FabSim is a very efficient and user friendly tool. It fosters the optimization of material flow and throughput and may give valuable support to investment decisions.