Friction Mechanism and Characteristics of Reticle Based on Contact Theory

Abstract

\n With the development of integrated circuits, the structure of chips becomes more and more complex, and the processing cost increases accordingly. To improve the productivity of lithography, the acceleration of the reticle stage should be increased to reduce the positioning time. However, the increase of acceleration will cause the relative slip between the reticle and the vacuum chuck, which seriously affects the accuracy and the product yield of lithography. To suppress the slippage, the friction mechanism and the characteristics between the reticle and the chuck are studied in this article. First, based on the Kogut–Etsion contact model and the Majumdar–Bhushan (MB) fractal contact model, the maximum static friction coefficient model between nano-scale surfaces was established. Then, the surface morphology parameters of reticle and chuck adsorption surface were obtained by atomic force microscopy (AFM) scanning. Finally, the maximum static friction force experiments show that the MB model is more suitable for the study of friction mechanism between reticle and vacuum chuck, and the model is more instructive for the suppression of reticle slip.