A Novel Vertical Closed-Loop Control Method for High Generation TFT Lithography Machine

A prominent problem of TFT lithography machine is that its plate stage's size and weight increase rapidly as it develops to higher generation. Because of plate stage's large size and heavy weight, it could be extremely difficult to achieve high bandwidth. Hence, it could be technical complicatedly and economic expensively to compensate vertical control error by the movement of plate stage. In this paper, a novel vertical closed-loop control method using the idea of coordinated movement of reticle stage and plate stage has been proposed. Experiment results show that, the total vertical control error based on our method has better performance, and CDU results based on these two methods are similar. However, our method has much higher technical feasibility and lower cost.