Air-based contactless wafer precision positioning system

Contactless sensing using charge coupled devices

Journal article (2022)

Authors

N. Saikumar Mechatronic Systems Design - Mechanical, Maritime and Materials Engineering
S. Hassan HosseinNia Mechatronic Systems Design - Mechanical, Maritime and Materials Engineering
R.A.J. van Ostayen Mechatronic Systems Design - Mechanical, Maritime and Materials Engineering
Research Group
Mechatronic Systems Design (Mechanical, Maritime and Materials Engineering) (TU Delft)
Copyright: © 2022 R.H.T. Hooijschuur, N. Saikumar, S. Hassan HosseinNia , R.A.J. van Ostayen
DOI
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https://doi.org/10.1177/13506501221132104
Precision positioning Air-bearing
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Published Date

2022

Language

English

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Faculty

Mechanical, Maritime and Materials Engineering

Department

Precision and Microsystems Engineering

Research Group

Mechatronic Systems Design

Abstract

This paper presents the development of a contactless sensing system and the dynamic evaluation of an air-bearing based precision wafer positioning system. The contactless positioning stage is a response to the trend seen in the high-tech industry, where the substrates are becoming thinner and larger to reduce the cost and increase the yield. Using contactless handling it is possible to avoid damage and contamination. The system works by floating the substrate on a thin film of air. A viscous traction force is created on the substrate by steering the airflow. A cascaded control design structure has been implemented to the contactless positioning system, where the Inner Loop Controller (ILC) controls the actuator which steers the airflow and the Outer Loop Controller (OLC) controls the position of the substrate by controlling the reference of the ILC. The dynamics of the ILC are evaluated and optimized for the performance of the positioning of the substrate. The vibration disturbances are also handled by the ILC. The bandwidth of the system has been improved to 300 Hz. For the OLC a linear charge-coupled device has been implemented as a contactless sensor. The performance of the sensing system has been analyzed. During control in steady state, this resulted in a position error of the substrate of 12.9 (Formula presented.) m RMS, which is a little more as two times the resolution. The bandwidth of the OLC is approaching 10 Hz.