KAIST Dong-Hyun Roh and Tae-Eog Lee 2015.10.16
ISMI 2015
Tools for K-Cyclic Schedule KAIST Dong-Hyun Roh and Tae-Eog Lee - - PowerPoint PPT Presentation
Characterizing Wafer Delays in Cluster Tools for K-Cyclic Schedule KAIST Dong-Hyun Roh and Tae-Eog Lee 2015.10.16 ISMI 2015 Table of Contents 1. Introduction 2. Preliminaries 3. Wafer Delays in Cluster Tools 4. Wafer Delay Regulation
KAIST Dong-Hyun Roh and Tae-Eog Lee 2015.10.16
ISMI 2015
2015.10.16 ISMI
3/22
Introduction
repeats a lot of tasks cyclically. If K timing patterns appear during a work cycle of a schedule, then the schedule is called a K-cyclic schedule. Usually, the tool has a K- cyclic schedule.
cannot be used in real industries.
the complexity of the schedule. Therefore it usually cannot assure the feasibility of the schedule for tight constraints.
consider two types of cluster tools: single-armed cluster tools and dual-armed cluster
balancing and a feedback control.
Introduction
4/22
Introduction
times within processing chambers [1], [3], [5], [6], [7], [8], [9]
we yet need a more direct insight on wafer delays.
Introduction
5/22
Cluster Tools
Token Delays in Timed Event Graphs Preliminaries
PM1 PM2 PM3 PM4 Loadlock Loadlock
6/22
Petri-nets and Event Graphs
tokens, places, and transitions.
graph.
holding times.
modelled by a Petri-net. If the robot task sequence is fixed, the behavior can be modelled by a TEG.
Token Delays in Timed Event Graphs Preliminaries
Petri-net Event Graph
π
1
π2 π3 π
4
π5 π6 π7 π8 π
1
π2 π3 π
4
π5 π6 π7 π8
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Timed Event Graphs
Token Delays in Timed Event Graphs Preliminaries
2 2 2 2 2 2 2
π
1
π2 π3 π
4
π5 π6 π7 π8
28 98 38 2
28 50 40 16
the critical circuit ratio means the average cycle time(π) of the tool.
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K-cyclic Schedule
Definition) K-cyclic schedule Let π¦π
π denote a π -th firing epoch of transition π. If π¦π π +πΏ β π¦π π = ππ is a constant but
π¦π
π +π β π¦π π is not βπ, 1 β€ π β€ πΏ, this schedule π¦π π βπ, π } is named a K-cyclic schedule.
And πΏ is called the cyclicity.
Definition) Time difference of a K-cyclic schedule π β π+
πΏ whose ππ β π¦π π+1 β π¦π π where transition π is one of transitions in the critical
circuit is called the time difference of a K-cyclic schedule.
bottleneck process determines the K-cyclic schedule. The wafer delays in PMs also dependent on the time difference.
π³
πΊπ = π³ β π where π is the average cycle time of the tool.
Token Delays in Timed Event Graphs Preliminaries
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Time Difference
2 2 2 2 2 2 2
π
1
π2 π3 π5 π6 π7 π8
28 148 38 2
28 50 40 16
1st-cycle 2nd-cycle 3rd-cycle
πΏ = 3
π¦4
1
π¦4
2
π¦4
3
π1 β π¦4
2 β π¦4 1
π2 β π¦4
3 β π¦4 2
π3 β π¦4
4 β π¦4 3 π=1 πΏ
ππ = πΏ β π = 150
Token Delays in Timed Event Graphs Preliminaries
π
4
10/22
Single-armed and Dual-armed Cluster Tools
has its own optimal robot sequence for a serial-parallel wafer flow pattern.
chambers except the bottleneck process.
Token Delays in Timed Event Graphs Wafer Delays in Cluster Tools
Backward Swap
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TEG for the Backward Sequence
ππ where ππ : the process time of πππ, π£, π, π€ : a robot task time for unloading, loading, and moving/transporting, respectively.
π13 ππ2 π3 π3π ππ π2 π23 π3 π1 π12 π2 π
1
π2 π3 π
4
π5 π6 π7 π8 π9 π
10
π
11
π
12
π2π ππ ππ1 π1 π
13
π
14
π
15
π31 π
16
π
1
π
3
π
2
Token Delays in Timed Event Graphs Wafer Delays in Cluster Tools
12/22
Wafer Delays in Single-armed Cluster Tools
Token Delays in Timed Event Graphs Wafer Delays in Cluster Tools
Theorem 1) For a single-armed cluster tool with a single bottleneck πππβ and a cyclicity π³, suppose the tool follows the backward sequence. Then the followings are satisfied:
π³ β π β πΏπ΄π] where πΏπ΄π is the maximum workload of πΈπ΅π (π β πβ).
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TEG for Swap Sequence
ππ : the process time of πππ, π£, π, π‘ : a robot task time for unloading, loading, and swap, respectively.
ππ₯ππ < πππβ πΆππππ₯ππ π generally, a dual-armed cluster tool has more
productivity than a single-armed cluster tool.
πππ π
1
π
2
π
1
π2 π3 π
4
π5 π6 π7 π8 π9 π
10
π
11
π
12
π
13
π
14
π
15
π
16
π
3
π1 ππ ππ1 π1 π1 π12 π2 π2 π23 π3 π3 π3 π3π ππ π2 Token Delays in Timed Event Graphs Wafer Delays in Cluster Tools
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Wafer Delays in Dual-armed Cluster Tools
Token Delays in Timed Event Graphs Wafer Delays in Cluster Tools
Theorem 2) For a dual-armed cluster tool with a single bottleneck πππβ and a cyclicity π³, suppose the tool follows the swap sequence. Then the followings are satisfied:
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Wafer Delays in a Single-armed Cluster Tool (Example)
1) πΈπ > πΈπ β πΊπ β πΏπ΄π, ππ β πΏπ΄π (π2 = 2π β π1) πππ1 = π β ππ1, 2π β ππ1 β π and πππ3 = 0, 0
Wafer Delays in Cluster Tools
π1
ππ1 2π β ππ1 ππ2 = π
2(π β ππ1)
ππ3 ππ1
16/22
Wafer Delays in a Single-armed Cluster Tool (Example)
2) πΈπ β€ πΈπ β πΊπ β πΏπ΄π, ππ β πΏπ΄π (π2 = 2π β π1) πππ1 = π β ππ1, 2π β ππ1 β π and πππ3 = 0, 0
Wafer Delays in Cluster Tools
π
ππ3 2π β ππ3 ππ2
2π β ππ1 β ππ3
ππ3 ππ1
ππ3 β ππ1
2π β ππ3 ππ3
17/22
Wafer Delays in a Dual-armed Cluster Tool (Example)
1) πΈπ > πΈπ β πΊπ β [πΏπ΄πΊ, ππ β πΏπ΄πΊ] and suppose that πππ βͺ ππ1, ππ3. Note : The range between πΏπ΄πΊ~πΏπ΄π, πΏπ΄π is relatively large.
Wafer Delays in Cluster Tools ππ1 2π β ππ1 ππ2
2(π β ππ1)
ππ3 ππ1
2π β πππ πππ
2(π β ππ3) π1
18/22
Wafer Delays in a Dual-armed Cluster Tool (Example)
2) πΈπ β€ πΈπ β πΊ β [πΏπ΄πΊ, ππ β πΏπ΄πΊ] and suppose that πππ βͺ ππ1, ππ3. Note : The range between πΏπ΄πΊ~πΏπ΄π, πΏπ΄π is relatively large.
Wafer Delays in Cluster Tools
π1 2(π β ππ3)
2π β ππ1 ππ1 ππ3 2π β ππ3 ππ2 2π β πππ πππ
ππ3 ππ1
2(π β ππ1)
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Wafer Delays Regulation Strategies
Wafer Delay Regulation Strategies
workload balancing.
1 1 π’3 π’2 π’4 2 3 5 π’1 delay => 0 π’π£ 2 5
Feedback Control
2 2 2 2 2 2
π
1
π2 π3 π
4
π5 π6
28 98 2 2 2 2 2 2
π
1
π2 π3 π
4
π5 π6
28 98 20 18
Workload Balancing
20/22
Feedback Control
their methodology, wafer delays of a certain PM can be controlled not to exceed the predetermined threshold regardless of the cyclicity.
For example, suppose that we want to equalize wafer delays of PMs. Since delays are ππ β πππ, the equal values of wafer delays can be obtained by equalizing ππ as π, for all π β΅ π=1
πΏ
π
π = πΏ β π . β ππΈπ΅π π
= π β πΏπ΄π
Token Delays in Timed Event Graphs Wafer Delay Regulation Strategies πππ π
1
π
2
π
1
π2 π3 π
4
π5 π6 π7 π
10
π
11
π
12
π
13
π
14
π
15
π
16
π
3
π1 ππ ππ1 π1 π1 π12 π2 π2 π23 π3 π3 π3 π3π ππ π2 π9 π8
π³ = π
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Workload Balancing
appropriately, i.e., increasing token holding times of robot task places in the TEG. Case 1) Case 2)
Token Delays in Timed Event Graphs Wafer Delay Regulation Strategies 2 2 2 2 2 2
π
1
π2 π3 π
4
π5 π6
28 98 20 2 2 2 2 2 2
π
1
π2 π3 π
4
π5 π6
28 98 38
Since there are no delays in the critical circuits, πΈπ΅π has no delays.
π
1
π
2
π
1
π
2
Again π³ becomes 1, so wafer delays of πΈπ΅π are equalized.
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Conclusion
schedules.
backward sequence is better than the swap in respect of wafer delays.
workload balancing.
constraints.
Token Delays in Timed Event Graphs Conclusion
2015.10.16 ISMI
Reference
[1] J.-H. Kim, T.-E. Lee, H.-Y. Lee, and D.-B. Park, βScheduling analysis of time-constrained dual-armed cluster tools,β IEEE Transactions on Semiconductor Manufacturing, vol. 16, no. 3, pp. 521β534, 2003. [2] J.-H. Kim and T.-E. Lee, βSchedule stabilization and robust timing control for time-constrained cluster tools,β in Proceedings of the IEEE International Conference on Robotics and Automation, Taipei, pp. 1039β 1044, 2003. [3] T.-E. Lee and S.-H. Park, βAn extended event graph with negative places and tokens for time window constraints,β IEEE Transactions on Automation Science and Engineering, vol. 2, no. 4, pp. 319β332, 2005. [4] T.-E. Lee, S.-H. Park, and C. Jung, βSteady state analysis of timed event graph with time window constraints,β Discrete Applied Mathematics, vol. 167, pp. 202β215, 2014. [5] T.-E. Lee, H.-Y. Lee, and S.-J. Lee, βScheduling a wet station for wafer cleaning with multiple job flows and multiple wafer-handling robots,β International Journal of Production Research, vol. 45, no. 3, pp. 487β 507, 2007. [6] J.-H. Kim and T.-E. Lee, βSchedulability analysis of time-constrained cluster tools with bounded time variations by an extended Petri net,β IEEE Transactions on Automation Science and Engineering, vol. 5, no. 3, pp. 490β503, 2008. [7] N. Q. Wu and M. C. Zhou, βA Petri net method for schedulability and scheduling problems in single-arm cluster tools with wafer residency time constraints,β IEEE Transactions on Semiconductor Manufacturing, vol. 21, no. 2, pp. 224-237, 2008. [8] N. Q. Wu and M. C. Zhou, βA closed-form solution for schedulability and optimal scheduling of dual-arm cluster tools with wafer residency time constraint based on steady schedule analysis,β IEEE Transactions on Automation Science and Engineering, vol. 7, no. 2, pp. 303-315, 2010. [9] Y. Qiao, N. Q. Wu, and M. C. Zhou, βReal-time scheduling of single-arm cluster tools subject to residency time constraints and bounded activity time variation,β IEEE Transactions on Automation Science and Engineering, vol. 9, no. 3, pp. 564β577, 2012. [10] T. Murata, βPetri nets: Properties, analysis and applications,β Proceedings of the IEEE, vol. 77, no. 4, pp. 541β580, 1989.
Reference
[11] Y. Qiao, N. Q. Wu, and M. C. Zhou, βPetri net modeling and wafer sojourn time analysis of single-arm cluster tools with residency time constraint and activity time variation,β IEEE Transactions on Semiconductor Manufacturing, vol. 25, no. 3, pp. 432β436, 2012. [12] C. Kim and T.-E. Lee, βFeedback control design for cluster tools with wafer residency time constraints,β Proceedings of the 2012 IEEE Conference on Systems, Man, and Cybernetics, Seoul, South Korea, pp. 3063β3068, 2012. [13] C. Kim and T.-E. Lee, βFeedback control of cluster tools for regulating wafer delays,β IEEE Transactions on Automation Science and Engineering, DOI: 10.1109/TASE.2015.2404921. [14] T.-E. Lee and M. E. Posner, βPerformance measures and schedules in periodic job shops,β Operations Research, vol. 45,
[15] T.-E. Lee, βStable earliest schedule for cyclic job shops: a linear system approach,β International Journal of Flexible Manufacturing Systems, vol. 12, no. 1, pp. 59β82, 2000. [16] F. L. Baccelli, G. Cohen, G. J. Olsder, and J. P. Quadrat, Synchronization and Linearity - An Algebra for Discrete Event
[17] S. Amari, I. Demongodin, J. J. Loiseau, and C. Martinez, βMax-plus control design for temporal constraints meeting in timed event graphs,β IEEE Transactions on Automatic Control, vol. 57, no. 2, pp. 462β467, 2012. [18] T.-E. Lee, R. Sreenivas, and H.-Y. Lee, βToken delays and generalized workload balancing for timed event graphs with application to cluster tool operation,β Proceedings of IEEE International Conference on Automation Science and Engineering, Shanghai, pp. 93β99, 2006.