Smith–EWMA run-to-run control schemes for a process with measurement delay

Jin, Ming; Tsung, Fugee

doi:10.1080/07408170802331243

Cited by 14 publications

(6 citation statements)

References 31 publications

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“…To control the amount of removal and to achieve an ideal thickness, lapping time is usually adjusted between runs. More about this process is also introduced in Li, Wang, and Yeh (2013) and Lin and Wang (2012) In a case in which wafer thickness before and after lapping are both known online, classical run-to-run controllers, such as an exponentially weighted moving average (EWMA) controller and its extensions (Ingolfsson and Sachs 1993;Tseng, Tsung, and Liu 2007), a double EWMA controller (Chen and Guo 2001) and other controllers (Fan et al 2002;Fan 2005;He, Wang, and Jiang 2009;Jin and Tsung 2009;Jen, Jiang, and Wang 2011), can be applied to generate recipes and to guide setting adjustments between runs. However, in the lapping process, accurate thickness values must be measured in a special inspection room with the aid of an expensive testing machine, which is both costly and timeconsuming.…”

Section: Introductionmentioning

confidence: 99%

“…Thus, researchers began to investigate and improve EWMA-type run-to-run controllers under a metrology delay. Jin and Tsung (2009) developed the Smith-EWMA run-to-run controller, introducing the Smith predictor, which was created specifically for time delay systems in control theory for EWMA controllers. A performance comparison with the EWMA and recursive-least-square controllers under the first-order autoregressive (AR(1)) and integrated moving average (IMA(1)) (1) disturbance conditions based on simulation is conducted; this comparison shows that the Smith-EWMA controller has better stability properties and also has a more satisfactory performance for process control.…”

Section: Introductionmentioning

confidence: 99%

“…To address a measurement delay, Jin and Tsung (2009) developed a specific Smith-EWMA control algorithm. To investigate the performance of the method that was proposed in this paper, the EWMA controller and the Smith-EWMA controller are also set up to control the same process.…”

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confidence: 99%

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A run-to-run control algorithm based on timely and delayed mixed-resolution information

Wang

Lin

2013

International Journal of Production Research

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In certain run-to-run (R2R) processes, timely accurate measurements are difficult to obtain due to slow laboratory measurement operations. Instead, only low-resolution categorical observations are observed online for important quality variables; continuous measurements for the same variables are provided after a specific amount of delay. Currently, most conventional R2R controllers cannot be applied if no continuous observations are available. It is therefore important to develop online algorithms for R2R process control based on mixed-resolution information that is partially timely and partially delayed. In this study, we take the lapping process in semiconductor manufacturing as an example and propose parameter estimation models with these mixed-resolution data for processes with the first-order autoregressive, AR(1), disturbance series. We also derive control strategies to generate recipes between production runs for better process control. The computational results of a performance evaluation show that the control performance of the proposed method is competitive compared to existing methods that are based on accurate measurements.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A run-to-run control algorithm based on timely and delayed mixed-resolution information

Wang

Lin

2013

International Journal of Production Research

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“…They illustrated that an RLS-type controller adjusted the process output to the target more efficiently. Jin and Tsung (2009) proposed the Smith-EWMA controller and compared the stability region and performance with a double EWMA controller for a drifted SISO process. They demonstrated that the Smith-EWMA controller could enlarge the stability region and achieve a better performance.…”

Section: Introductionmentioning

confidence: 99%

Modified EWMA controller subject to metrology delay

2013

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The resource and capacity limitations of the metrology equipment used in the creation of integrated circuits result in delay being a common issue for the practical implementation of run-to-run control scheme. In the literature, several papers have provided the means of using metrology delay data or Virtual Metrology (VM) prediction models on the transient behavior and asymptotic stability of Exponentially Weighted Moving Average (EWMA) controllers. However, these procedures still suffer from large bias and/or variation of the process response variable. To overcome this difficulty, a modified EWMA controller is proposed that adjusts the process by using both the metrology delay data and VM information. The analytical expression of the process output of this developed controller and its long-term stability along with short-term output performance are derived. Furthermore, under some specific parameter settings, a more comprehensive study is presented to illustrate that the proposed controller has the capability to reduce the total mean square error of process response variable compared with existing controllers.

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“…Su et al [24] presented an approach to determine maximum tolerable sampling intervals, maximum tolerable delay, and measurement priority to improve control performance of the process. Jin and Tsung [25] introduced a Smith predictor control scheme into EWMA controllers, and compared stability properties of this Smith-EWMA and traditional EWMA runto-run controllers.…”

mentioning

confidence: 99%

Takagi–Sugeno Model Based Analysis of EWMA RtR Control of Batch Processes With Stochastic Metrology Delay and Mixed Products

Zheng

Wong

Wang

et al. 2014

IEEE Trans. Cybern.

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In many batch-based industrial manufacturing processes, feedback run-to-run control is used to improve production quality. However, measurements may be expensive and cannot always be performed online. Thus, the measurement delay always exists. The metrology delay will affect the stability and performance of the process. Moreover, since quality measurements are performed offline, delay is not fixed but is stochastic in nature. In this paper, a modeling approach Takagi-Sugeno (T-S) model is presented to handle stochastic metrology delay in both single-product and mixed-product processes. Based on the Markov characteristics of the delay, the membership of the T-S model is derived. Performance indices such as the mean and the variance of the closed-loop output of the exponentially weighted moving average (EWMA) control algorithm can be derived. A steady-state error of the process output always exists, which leads the output deviating from the target. To remove the steady-state error, an algorithm called compensatory EWMA run-to-run (COM-EWMA-RtR) algorithm is proposed. The validity of the T-S model analysis and the efficiency of the proposed COM-EWMA-RtR algorithm are confirmed by simulation.

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Smith–EWMA run-to-run control schemes for a process with measurement delay

Cited by 14 publications

References 31 publications

A run-to-run control algorithm based on timely and delayed mixed-resolution information

A run-to-run control algorithm based on timely and delayed mixed-resolution information

Modified EWMA controller subject to metrology delay

Takagi–Sugeno Model Based Analysis of EWMA RtR Control of Batch Processes With Stochastic Metrology Delay and Mixed Products

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