Run-to-run control and performance monitoring of overlay in semiconductor manufacturing

Bode, Christopher; Ko, Byung Su; Edgar, Thomas F.

doi:10.1016/s0967-0661(03)00154-0

Cited by 68 publications

(19 citation statements)

References 5 publications

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“…with T p = 8, which provides a measure for machine overlay [3] and typically resembles a low-pass filter. Additionally the moving standard deviation filter operation:…”

Section: Resultsmentioning

confidence: 99%

Self-tuning of a switching controller for scanning motion systems

Heertjes

Nijmeijer

2012

Mechatronics

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a b s t r a c tFor a class of switching motion control systems, in particular scanning stage systems, a self-tuning method is proposed to find the optimal switching control parameters. In this method, a combined model/data-based approach is used to derive the gradients with respect to these parameters. The gradients are used in an update scheme which subsequently renders an updated set of parameters. Each set is applied to the machine while operating under closed-loop conditions. By repeating the process, the switching control parameters show convergence to an optimized set of values that induce servo performance inaccessible to linear control. This is because high-gain feedback is incidentally switched on to suppress large amplitude oscillations and is otherwise switched off to avoid amplification of small amplitude noises. In time-domain this gives improved low-frequency disturbance rejection properties with minimal deterioration of the sensitivity to high-frequency noises. Stability and convergence of the switching control system and optimization scheme in the face of perturbations is proved using Lyapunov analysis. Servo performance is demonstrated on a commercial and nano-positioning scanning motion system.

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“…with T p = 8, which provides a measure for machine overlay [3] and typically resembles a low-pass filter. Additionally the moving standard deviation filter operation:…”

Section: Resultsmentioning

confidence: 99%

Self-tuning of a switching controller for scanning motion systems

Heertjes

Nijmeijer

2012

Mechatronics

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“…Overlay [9] is a measure for position accuracy, hence the ability to perform a new scan atop a previous one. In terms of servo control performance, overlay can be assessed through the moving average filter operation.…”

Section: A Performance Measuresmentioning

confidence: 99%

Performance-Improved Design of N-PID Controlled Motion Systems With Applications to Wafer Stages

Heertjes

Schuurbiers²,

Nijmeijer

2009

IEEE Trans. Ind. Electron.

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Abstract-A nonlinear filter design is proposed to improve nanopositioning servo performances in high-speed (and generally linear) motion systems. The design offers a means to adapt fundamental control design tradeoffs-like disturbance suppression versus noise sensitivity-which are otherwise fixed. Typically performance-limiting oscillations in the feedback system that benefit from extra control are temporarily upscaled and subjected to nonlinear weighting. For sufficiently large amplitudes, this nonlinear filter operation induces extra controller gain. Oscillations that do not benefit from this extra control (typically because they represent noise contributions that should not be amplified) remain unscaled and, as such, do not induce extra controller gain. The combined usage of linear weighting filters with their exact inverses renders this part of the nonlinear filter design strictly performance based. The effective means to improve servo performance is demonstrated on a short-stroke wafer stage of an industrial wafer scanner. Since the nonlinear filter design is largely based on Lyapunov arguments, stability is guaranteed along the different design steps.

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“…with n a scanning time-scale parameter, essentially is a lowpass filter operation on the discrete-time error e(i), which is used to express the ability to position a single exposed wafer layer atop another; so-called scanning overlay [16]. The moving standard deviation filter operation, or…”

Section: Design For Performancementioning

confidence: 99%