Motivation and Approach
Wafer handling robots are used to transport wafers inside the vacuum
environment of IC
fabrication tools. Major concerns for the robot performance are:
- Speed and acceleration: Fast motion is desired to reduce production time, however, the wafer is placed on the end-effector of the robot without any fixture. Friction is the only force preventing sliding so acceleration has to be limited to avoid sliding.
- Accuracy of tracking and positioning: the reference trajectory is designed to be smooth to avoid sliding. It is important to reduce tracking error to ensure the smoothness of the motion.
- Vibration and oscillation may cause the sliding of wafers, which generates contaminating particles and even leads to wafer tip-over.
|An IC fabrication tool||The wafer handling robot inside an IC fabrication tool|
Our research aims at improving the robot control performance in above aspects. Meanwhile, the robustness, ease of implementation, and ease of tuning shall also be fully considered. Major approaches include:
- Model-based dynamics compensation.
- Controller tuning using distributed auxiliary sensing.
- Disturbance compensation based on adaptive modeling and identication.
With the proposed approaches, the reference trajectory can be optimized for maximum smoothness, and the following error is signicantly reduced by model-based dynamics and disturbance compensation.
Recent Key Publications
- X. Yu, C. Wang, Y. Zhao, and M. Tomizuka, "Dynamics Modeling and Identication of a Dual-blade Wafer Handing Robot," in Proceedings of the Sixth ASME Dynamic Systems and Control Conference (DSCC), 2013
- C. Wang, X. Yu, and M. Tomizuka, "Fast Modeling and Identication of Robot Dynamics using the Lasso," in Proceedings of the Sixth ASME Dynamic Systems and Control Conference (DSCC), 2013
|Cong Wang (graduated)||Graduate student|
|Xiaowen Yu||Graduate student|