Design of Microstructure Parameters on a Small Multi-Throttle Aerostatic Guideway in Photolithography

Abstract A compact multi-throttle aerostatic guideway is the preferred structure for high precision and acceleration motion in the variable-slit system (VS) of photolithography. The presence of microstructure, such as recesses and grooves, on the guideway working surface has been found to improve the loading performance. Nevertheless, the effects on the guideway performance of changing the microstructure on the micron level are not yet clear. The mesh adaptation method, which was proposed by the authors, is employed in this paper to quantitatively study the influences of four microstructure parameters. The effect of tuning these parameters on the loading performance is revealed. The level of impact determines the proposed design process of the parameters. The characteristic feature of the proposed design process is that the working points of carrying capacity, stiffness, and rotational stiffness are unified under two-way adjusting by means of recess parameters. According to the proposed design process and tuning method, the restriction of supply pressure is lifted to a certain extent and the mutual tradeoff among the loading performances is relieved. The experimental results show that the rotational stiffness of the designed guideway, based on the tuned parameters, reached 21.4 × 103 Nm∙rad-1 and increased by 69.8%. In a scanning test of the applied VS on argon fluoride laser (ArF) photolithography, the average scanning acceleration reached 67.5 m∙s-2, meeting the design specification.