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November 2010

Manual as pdf file added.

December 2007

Some update on the help file.

October 2005

A mini-fab simulation example has been added to the web site to demonstrate re-entrant process flows in a simple, but already intriguing example.

November 2004

FabSim now has an interface to a user programmable rule set. A C++ dynamic link library holds user defined dispatching rules. Local as well as global rules may be defined. All fab data (toolsets, processes, lots, buffers) are available to support customer modeling.

October 2004

The occupancy of each toolset buffer may be monitored while the simulation is progressing, as well as the WIP (work in process).

WSPT (weighted shortest processing time) is another new dispatching rule. The number of wafers per lot is chosen as the weight.

September 2004

Lot input data may now be generated by drawing from statistical distributions and random number generators (interarrival time, lot size, priority).

Earliest due date (EDD) has been added to the dispatching rules.

Besides gaussian distribution processing step duration may now be drawn from an exponential distribution.

Batching (e.g. within a furnace tube) may now either be determined by lot number or by wafer count.


May 2004

Operator data (time an operator needs for a specific task) may now be evaluated to yield the personnel required to run the factory under the given load.


April 2004

A new optimization algorithm is integrated into FabSim. It optimizes the tool count of a semiconductor factory with given process mix and throughput required.

FabSim Interactive has a new appearance. It's main window now concentrates on the user interface needed to start batch or interactive opration. If interactive operation is choosen, a second window with more controls opens up.

The stochastic times until machine failure mtbf and repair times mttr are now distributed optionally according to the Gamma distribution.

The simulator code has been further optimized.


February 2004

ODD (operation due date) has been added to the dispatching rules of FabSim.

Toolset optimization for a given throughput using FabSim Interactive has been tested. Results look promising and are available with reasonable CPU time.

The use of all random number generators has been consolidated. You may now either set a seed, then all FabSim runs will yield the same results, provided no other input data have been changed. If no seed is specified, a seed for all random number generators will be derived from your computer system time, that is consecutive FabSim runs will deliver different results.


January 2004

New options to FabSim:

Further new options include:


December 2003

A paper on FabSim has been presented at the Winter Simulation Conference 2003 in New Orleans at December 8th.

Please refer for the abstract to http://www.informs-cs.org/wsc03papers/abstracts03/SE.htm#vogth771800 . The full paper is available for download at http://www.informs-cs.org/wsc03papers/174.pdf .

FabSim Interactive now has several stop modes. For example the simulation may be set to halt and wait for input as soon as a specified lot has reached a specified step during processing. Another stop mode watches the number of lots in the buffer of a given toolset for undercutting or exceeding a given value.

FabSim adds more dispatching rules. You now may choose a lot from the toolset buffer for processing either by FIFO (first in, first out, sometimes called FCFS, first come, first serve) rule, CR (critical ratio) rule or SPTF (shortest processing time first) rule. SPTF comes with a variable maximum waiting time. Each toolset may run under a different rule.

The setup of machines (models for steppers and implanters included) has been enhanced by the capability to run a setup avoidance policy. Depending on setup requirements and the current machine status, setup may be reduced or even avoided completely.


September 2003

FabSim 2.0 is out! It's code no longer depends on SystemC. The structure originally provided by SystemC however has been implemented directly in C++. The executable size has become smaller, the simulation speeds up by a factor of two.


April 2003

FabSim now is 30% faster. The reorganization of the machine model also helped to reduce the size of the executable code.


March 2003

A paper on FabSim has been presented at the ASMC 2003 conference in Munich at March 31st.

Please see http://www.semi.org/web/wcontent.nsf/url/ASMCHome for further information.


October 2002

FabSim Interactive is out!

The new simulator FabSim Interactive combines the simulation capabilty of current FabSim.exe with the unique capability to run the simulation for an arbitrary amount of time, then change parameters and continue. You will gain interactive control over the fab as in real life!

See Interactive simulation for more information on FabSim Interactive or Downloads for download of a demo version with limited toolset count, but otherwise full simulation capability.


August 2002

Many new features have been added to FabSim:

The input format for starting lots is very flexible now. You may start single lots and sequences of lots (including loops) at any time step. Two different tool set setup times may be defined depending on the tool's previous setup. Typicals modes for stepper and implanter setup are available, others will be added later. For any process step in a run sheet a tool set dependent rework sequence may be defined. In certain process steps the number of wafers in a lot determines the overall throughput. Input and output directories may be set as environmental variables.