Title :
Rejection of aliased disturbances in a pulsed light source
Author :
Riggs, Daniel J. ; Bitmead, Robert R.
Author_Institution :
Cymer, Inc., San Diego, CA, USA
Abstract :
We study a disturbance rejection problem in a pulsed light source with the aim of yielding improved performance over existing control techniques. The disturbances of interest include an offset with reset properties and sinusoids which appear aliased in the measured data. The light source is pulsed at varying pulse rates yet actuators move in continuous-time, yielding a system which blends aspects of continuous-time and variable data rate discrete-time. We employ continuous-discrete Kalman filtering ideas for state estimation and establish and solve a regularized minimum variance control problem under a disturbance rejection framework. We show that the proposed controller has the capacity to remove aliased sinusoids from the measured output and yields improved performance over existing light source algorithms.
Keywords :
Kalman filters; actuators; light sources; state estimation; actuators; aliased disturbances rejection; continuous discrete Kalman filtering; minimum variance control; pulsed light source; state estimation; Actuators; Feedback control; Frequency; Kalman filters; Light sources; Lighting control; Lithography; Pulse measurements; Throughput; Ultraviolet sources;
Conference_Titel :
Decision and Control, 2009 held jointly with the 2009 28th Chinese Control Conference. CDC/CCC 2009. Proceedings of the 48th IEEE Conference on
Conference_Location :
Shanghai
Print_ISBN :
978-1-4244-3871-6
Electronic_ISBN :
0191-2216
DOI :
10.1109/CDC.2009.5399935