Patent ID: 6456953
Filing Date: 2002-09-24
Classification: G03F

Abstract:
A method for correcting reticle X shift and reticle Y shift between a reticle and a stage in a step-and-repeat exposure system, wherein there are at least two temperature sensors associated with the reticle, sensor 1 and sensor 2, sensor 1 having a sensor 1 temperature output and sensor 2 having a sensor 2 temperature output, the method comprising the steps of:(a) estimating an X shift (Xtotal shift) by multiplying a coefficient 1 representing a reticle X shift per degree of temperature output of sensor 1 with a difference of the temperature output of sensor 1 between a first and a second time; (b) estimating a Y shift (Ytotal shift) by multiplying a coefficicent 2 representing a reticle Y shift per degree of the sum of temperature outputs of sensors 1 and 2 with the difference between the sum of the temperature outputs of sensor 1 and sensor 2 between said first and said second time; and (c) correcting reticle X shift and reticle Y shift between said reticle and said stage using said X shift (Xtotal shift) and Y shift (Ytotal shift).