Predictive-model-based MIMO motion control of an unstable 6-DoF hexapod stage for overlay measurements
| Autor: | Gert Witvoet, Max Baeten, Stefan Kulper, Geerten Kramer |
|---|---|
| Přispěvatelé: | Control Systems Technology |
| Jazyk: | angličtina |
| Rok vydání: | 2017 |
| Předmět: | |
| Zdroj: | 1st Annual IEEE Conference on Control Technology and Applications, CCTA 2017, 2017-January, 726-731 CCTA |
| DOI: | 10.1109/CCTA.2017.8062548 |
| Popis: | Correct functionality of semiconductor devices depends on the overlay performance between device layers. Future smaller device features consequently require more accurate overlay metrology tools. In this paper we present a large dynamic range AFM overlay tool to directly measure marker-to-feature distances, and focus on the controller design of the large stroke 6-DoF hexapod motion stage which is at the heart of this tool. The stage is open-loop unstable due to magnetic gravity compensation, which calls for an initial model-based MIMO controller design, which is based on a finite-element modal analysis, geometric decoupling and SISO loopshaping. This controller is successfully validated in experiments; further controller improvements after closed-loop system identification yield a closed-loop position error of just 1 nm RMS. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|