INTERFEROMETRY SYSTEM ERROR COMPENSATION IN TWIN STAGE LITHOGRAPHY TOOLS

摘要

A device and methods for monitoring the position of a stage in a twin stage lithography tool are disclosed. The device (100) includes an exposure system (155), a pair of stages (110, 120) that can hold and transport a wafer, and an interferometry system comprised of one or more interferometers (125A, 115C) for monitoring the locations of the stages during operation of the device. The device operates by first exposing the first wafer to radiation from the exposure system and then using the interferometers to monitor the position of the first wafer with respect to a reference position during the radiation exposure. The first stage is removed and replaced with the second stage and wafer, and the process is repeated. During the process, a compensation with a measured interference phase is performed based on a first or second predetermined representation indicative of systematic errors of the system.