Run-to-run control methods based on the DHOBE algorithm

Zhang, Chang; Deng, Hao; Baras, John S.

doi:10.1016/s0005-1098(02)00197-8

Cited by 14 publications

(6 citation statements)

References 15 publications

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“…A process control method known as RtR control, which has thus far been used mostly in the modern semiconductor industry, [19][20][21] is introduced to effectively implement MAF in precision mold finishing. RtR control is a form of discrete-time process control in which a particular equipment process recipe is modified between equipment runs to compensate for process drift, large shifts, and other disturbances to keep the outputs at the prescribed target values.…”

Section: Rtr Controlmentioning

confidence: 99%

Run-to-run process control of magnetic abrasive finishing using bonded abrasive particles

Ahn

Lee

2012

Proceedings of the Institution of Mechanical Engineers, Part B:

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In this study, magnetic abrasive finishing, a polishing method using novel bonded magnetic abrasive particles, is implemented in the nanometer-scale surface polishing of STAVAX (S136) die steel workpieces, which are widely used for precision lens molds. With the aid of run-to-run control, a process control method, nanometer-scale mold surface quality is achieved and maintained over multiple runs. A specially designed magnetic quill equipped with an electromagnet was connected to a computer numerical control machining center to construct the polishing setup. Based on Preston’s equation and a set of preliminary experiments, design of experiment and analysis of variance were used to select and evaluate the relevant control parameters for the process. The finishing results show that the magnetic abrasive finishing has a nanometer-scale finishing capability (down to 8 nm surface roughness). Under run-to-run control with the selected parameters, the surface roughness values were successfully maintained below the target values (10 and 50 nm for Ra and Rmax, respectively), which shows that the proposed magnetic abrasive finishing scheme is readily adaptable to ultraprecision polishing applications, which are subject to disturbances for a relatively long period of time.

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Section: Rtr Controlmentioning

confidence: 99%

Run-to-run process control of magnetic abrasive finishing using bonded abrasive particles

Ahn

Lee

2012

Proceedings of the Institution of Mechanical Engineers, Part B:

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“…A second-order polynomial is employed in [106] and [112], where the estimation technique is based on a steady-state design of experiments (DOE). A different approach has been taken in [129], where a bounding ellipsoid algorithm is employed to estimate parameters of a second-order polynomial model. At each iteration, the algorithm returns an outer bounding ellipsoid of the likely process parameter set.…”

Section: ) Multivariable Modelsmentioning

confidence: 99%

Estimation and Control in Semiconductor Etch: Practice and Possibilities

Ringwood

Lynn

Bacelli

et al. 2010

IEEE Trans. Semicond. Manufact.

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Abstract-Semiconductor wafer etching is, to a large extent, an open-loop process with little direct feedback control. Most silicon chip manufacturers rely on the rigorous adherence to a "recipe" for the various etch processes, which have been built up based on considerable historical experience. However, residue buildup and difficulties in achieving consistent preventative maintenance operations lead to drifts and step changes in process characteristics. This paper examines the particular technical difficulties encountered in achieving consistency in the etching of semiconductor wafers and documents the range of estimation and control techniques currently available to address these difficulties. An important feature of such an assessment is the range of measurement options available if closed-loop control is to be achieved.Index Terms-Closed-loop control, plasma etch, run-to-run control, semiconductor wafer, state estimation, virtual metrology.

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“…Several strategies have been proposed for the update of the model parameters, depending on the properties of the process and of the chosen process model. They include exponentially weighted moving average (EWMA) filters, double EWMA, least‐squares parameter estimation, and many more 18–23. Usually the measurements from the previous run (batch) k − 1 are used to compute an estimate of the parameters for run (batch) k , e.g.…”

Section: Run‐to‐run Control For Membrane Filtrationmentioning

confidence: 99%

Run‐to‐run control of membrane filtration processes

2007

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in Wiley InterScience (www.interscience.wiley.com).Membrane filtration processes are often operated cyclically, where one cycle comprises a filtration and a backwashing phase. Due to the complex mechanisms involved, these processes are mostly operated with fixed values of the manipulated variables, leaving much of the economical potential unexplored. A model-based run-to-run process control approach is introduced, in which the manipulated variables are optimized after each filtration cycle. The approach is evaluated in a case study on submerged membrane filtration in wastewater treatment. A simple, computationally inexpensive process model is developed. The resulting model-based controller is tested in a simulation environment employing a validated reference model. It yields excellent results with respect to prediction quality and optimization results.

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Run-to-run control methods based on the DHOBE algorithm

Cited by 14 publications

References 15 publications

Run-to-run process control of magnetic abrasive finishing using bonded abrasive particles

Run-to-run process control of magnetic abrasive finishing using bonded abrasive particles

Estimation and Control in Semiconductor Etch: Practice and Possibilities

Run‐to‐run control of membrane filtration processes

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