This article discusses the control of the lithographic plate movement in extreme ultraviolet scanners using optimal performance algorithms. The relevance of the topic is due to the new requirements of the semiconductor industry for positioning accuracy during the exposure of silicon substrates. Issues arising from chatter — unwanted oscillations caused by magnetostrictive drives — are addressed. An approach based on the Pontryagins maximum principle and sliding mode control methods is proposed for damping oscillations. Various control functions, including the signum function and hyperbolic tangent, are investigated to minimize the negative impact of chatter on the mechanical system. Simulation results show that the use of smooth control functions effectively suppresses oscillations and increases positioning accuracy, which is critical for the fabrication of complex integrated circuits.
Petrakov et al. (Wed,) studied this question.