1. © January 27, 2006 Dr. Lynn Fuller, Motorola Professor Simulation Page 1 Rochester Institute of Technology Microelectronic Engineering ROCHESTER INSTITUTE OF TECHNOLOGY MICROELECTRONIC ENGINEERING  Computer Simulation of Factory Performance  Katie McConky  ISE Graduate Student  Rochester Institute of Technology  82 Lomb Memorial Drive  Rochester, NY 14623-5604  ktr6315@rit.edu ktr6315@rit.edu

2. © January 27, 2006 Dr. Lynn Fuller, Motorola Professor Simulation Page 2 Rochester Institute of Technology Microelectronic Engineering OUTLINE Overview of Modeling Verification and Validation of Models Model Accuracy Statistical Analysis AutoSched AP – Brooks Automation AutoMod– Brooks Automation Example Simulation Problems

3. © January 27, 2006 Dr. Lynn Fuller, Motorola Professor Simulation Page 3 Rochester Institute of Technology Microelectronic Engineering Overview of Modeling Semiconductor Fabs are extremely complex Reentrant Manufacturing High variability Long Process Routes Complicated batching and sequencing criteria Simulation modeling can take everything into account in order to answer questions about the fab.

4. © January 27, 2006 Dr. Lynn Fuller, Motorola Professor Simulation Page 4 Rochester Institute of Technology Microelectronic Engineering Verification and Validation Verification - Check that the model is acting how you expect it to act. - Dispatching Rules - Processing Times and other fundamentals Validation -Model results must resemble the actual fab: -Cycle Time -Total WIP Levels -WIP by Area -Model Outs -Tool Throughput

5. © January 27, 2006 Dr. Lynn Fuller, Motorola Professor Simulation Page 5 Rochester Institute of Technology Microelectronic Engineering Validation

6. © January 27, 2006 Dr. Lynn Fuller, Motorola Professor Simulation Page 6 Rochester Institute of Technology Microelectronic Engineering Validation Model Data

7. © January 27, 2006 Dr. Lynn Fuller, Motorola Professor Simulation Page 7 Rochester Institute of Technology Microelectronic Engineering Validation Actual Data

8. © January 27, 2006 Dr. Lynn Fuller, Motorola Professor Simulation Page 8 Rochester Institute of Technology Microelectronic Engineering Model Accuracy §Models can be very accurate for short periods of time

9. © January 27, 2006 Dr. Lynn Fuller, Motorola Professor Simulation Page 9 Rochester Institute of Technology Microelectronic Engineering Model Accuracy: Common Misconception Starting off with conditions that are 80% correct in the fab does not lead to a model that is 80% correct. Parameter Time

10. © January 27, 2006 Dr. Lynn Fuller, Motorola Professor Simulation Page 10 Rochester Institute of Technology Microelectronic Engineering Model Accuracy Time Parameter Obtain the most accurate picture of the fab as possible.

11. © January 27, 2006 Dr. Lynn Fuller, Motorola Professor Simulation Page 11 Rochester Institute of Technology Microelectronic Engineering Model Accuracy §To maintain an accurate / valid model you must: §Generate route and station files very quickly §Load a snapshot of the WIP into your model §Collect and update process times and other parameters frequently §How do we accomplish all this? §Create an automated system to generate an entirely new model on a regular basis.

12. © January 27, 2006 Dr. Lynn Fuller, Motorola Professor Simulation Page 12 Rochester Institute of Technology Microelectronic Engineering Statistical Analysis §Models can account for process variability. (models include some random event generators, for example: when equipment goes down) §It is therefore important to run a simulation more than once. §Multiple Replications §Simulation results should be reported as confidence intervals on a mean value.

13. © January 27, 2006 Dr. Lynn Fuller, Motorola Professor Simulation Page 13 Rochester Institute of Technology Microelectronic Engineering AUTOSCHED from Brooks Automation Inc.

14. © January 27, 2006 Dr. Lynn Fuller, Motorola Professor Simulation Page 14 Rochester Institute of Technology Microelectronic Engineering AutoSched AP and AutoMod §AutoSched AP: §Is an object-oriented modeling tool. §Uses a Windows-based Excel spreadsheet interface. §Is integrated with the APF Repository, APF Reporter, and Real Time Dispatcher. §AutoMod: §3-D graphics §Automated Material Handling Systems (AMHS) §Can be integrated with AutoSched AP models

15. © January 27, 2006 Dr. Lynn Fuller, Motorola Professor Simulation Page 15 Rochester Institute of Technology Microelectronic Engineering AutoSched AP Excel File

16. © January 27, 2006 Dr. Lynn Fuller, Motorola Professor Simulation Page 16 Rochester Institute of Technology Microelectronic Engineering AutoMod Fab Partial Fab Model www.ismi.sematech.org/modeling/simulation

17. © January 27, 2006 Dr. Lynn Fuller, Motorola Professor Simulation Page 17 Rochester Institute of Technology Microelectronic Engineering Typical Problems §How many tools should I purchase for a new step? §Depends on Desired Queue Length §Depends on Desired Queue Time §Importance: §Simulation results were used to justify the purchase of an extra tool in order to keep queuing times and queue lengths at a desired minimum.

18. © January 27, 2006 Dr. Lynn Fuller, Motorola Professor Simulation Page 18 Rochester Institute of Technology Microelectronic Engineering Typical Problems §If I remove tool dedication from one step, will I get increased tool utilization or a decrease in cycle time? ARF 1 ARF 2 ARF 3 ARF 1 ARF 2 ARF 3 ARF 1 ARF 2 ARF 3 ARF 1 ARF 2 ARF 3 DT AA M0 GC

19. © January 27, 2006 Dr. Lynn Fuller, Motorola Professor Simulation Page 19 Rochester Institute of Technology Microelectronic Engineering Results of M0 Dedication Removal 37.60 37.58 37.62 Days

20. © January 27, 2006 Dr. Lynn Fuller, Motorola Professor Simulation Page 20 Rochester Institute of Technology Microelectronic Engineering Results of M0 Dedication Removal §Importance of Dedication Study: §If we could show through simulation that tool utilization or cycle time would improve the pilot lots for M0 dedication removal could have been prioritized, to make the change happen faster.

21. © January 27, 2006 Dr. Lynn Fuller, Motorola Professor Simulation Page 21 Rochester Institute of Technology Microelectronic Engineering Typical Problems §Forecasting wafer outs: §What will be my outs of each product at the end of the week? §Importance: §Notify backend facilities of expected shipments. §Update financial people on fab productivity. §Time consuming to do forecasts by hand.

22. © January 27, 2006 Dr. Lynn Fuller, Motorola Professor Simulation Page 22 Rochester Institute of Technology Microelectronic Engineering Typical Problems §What recipes should I pair together on my etch or films tool so that my robot is not overworked? §Special software exists called ToolSim to model individual tools such as cluster tools and litho trackscluster tools §Importance §You can test different recipe variations and combinations before implementing them in the fab. B A C D Load Port 1 Load Port 2

23. © January 27, 2006 Dr. Lynn Fuller, Motorola Professor Simulation Page 23 Rochester Institute of Technology Microelectronic Engineering References §www.sematech.orgwww.sematech.org §www.Brooks.comwww.Brooks.com