High Accuracy Repeatability of the Stage Position on a Stepper

Abstract

Recently, it is difficult to design a fully rigid base-frame within the limited weight restriction. The aim of this paper is to propose a method of compensation for the stage position measurement error occurred by the elastic deformation in the base frame. First, it is shown with analysis and simulation, that the method improves the stage positioning accuracy. Next, it is shown with experiment that the standard deviation of the stage repeatability if improved from 9.4nm to 4.5nm. It shows also that this method is effective in making semiconductor lithography equipments lightweight.