Friction Mechanism and Characteristics of Reticle Based on Contact Theory

Abstract

With the development of integrated circuits, the structure of chips becomes more and more complex, and the processing cost increases accordingly. In order to improve the productivity of lithography, the acceleration of reticle stage should be increased to reduce the positioning time. However, the increase of acceleration will cause the relative slip between reticle and vacuum chuck, which seriously affects the accuracy and product yield of lithography. In order to suppress the slippage, the friction mechanism and characteristics between reticle and chuck are studied in this paper. Firstly, based on KE contact model and 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 was 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.