Control of Wafer Scanners: Methods and Developments

Hans Butler, Marcel F. Heertjes, N.J. Dirkx, S.H. van der Meulen, R. Ahlawat, K. O'Brien, J. Simonelli, K-T. Teng, Y. Zhao

Research output: Chapter in Book/Report/Conference proceedingConference contributionAcademicpeer-review

24 Citations (Scopus)


In this tutorial paper, control design aspects of wafer scanners used in the semiconductor industry will be highlighted. At the same time, challenges for control design development as to meet the ever increasing demands on accuracy and speed are presented. Mechatronic systems that will be discussed are: (a) the light source needed to generate the ultraviolet light that is used for wafer exposure, (b) the optical and metrology systems needed for accurate measurement and imaging, and (c) the reticle and wafer stage systems needed for accurate and fast positioning. The control challenges associated with these systems mainly involve dealing with: (a) rejection of high frequency aliased disturbances, (b) large-scale or fast-updated (state) reconstruction, (c) vibration control and isolation in view of structural vibrations and disturbances, (d) inherent design tradeoffs like Bode's sensitivity integral and gain-phase relationships, (e) multivariable plant identification of (quasi-static) deformations and structural dynamics for point-of-interest control, and (f) thermal modelling, model reduction, and the control of (local) time-varying deformation. Results will be discussed using representative examples.
Original languageEnglish
Title of host publication2020 American Control Conference, ACC 2020
PublisherIEEE Control Systems Society
Number of pages18
ISBN (Electronic)9781538682661
Publication statusPublished - 27 Jul 2020


  • advanced motion control
  • feedback/feedforward control
  • light source
  • nano-precision mechatronics
  • observer design
  • thermal control
  • vibration isolation & control
  • wafer scanners
  • wavelength control.


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