Synchronous error correction system for scanning motions of reticle stage and wafer stage of stepping scanning protection photoetching machine

Abstract

The invention discloses a synchronous error correction system for scanning motions of a reticle stage and a wafer stage of a stepping scanning protection photoetching machine. The synchronous error correction system comprises a motion trace planning module, a motion control module, a motion execution module and a synchronous error correction module. The synchronous error correction system has the advantages that the trace planning module is used for planning and digitalizing accelerations, speeds and position traces of the wafer stage and the reticle stage in a scanning and exposing process, can perform corresponding trace planning according to motion demands of different workpiece stages and is high in portability; on the basis of the characteristic of a synchronous error of the stepping scanning protection photoetching machine during scanning and exposing, an aim of reducing the synchronous error is fulfilled by reducing a tracing error of the wafer stage and a phase difference of a common-frequency partial signal in a tracking signal of the reticle stage; and the error correction method is analyzed on the basis of the characteristic of the synchronous error; and a frequency signal in the tracking error is pre-estimated by a forecasting module in the synchronous error correction module, so that the running speed of the system can be increased.

Description

technical field [0001] The present invention relates to the technical field of special equipment for microelectronics, in particular to a step-and-scan projection lithography machine mask table silicon wafer stage scanning movement synchronization error correction system, which is mainly used in the step-scan projection lithography machine to realize the scanning exposure process Correction of synchronization error between wafer stage and mask stage. Background technique [0002] Step-and-scan projection lithography technology is a cutting-edge technology in IC processing. It uses the synchronous movement of the mask stage and the silicon wafer stage to project the graphics on the mask onto the silicon wafer through the optical system, and then after shaping and developing And other processes, and finally reproduce the graphics with reduced magnification on the silicon wafer. Scanning exposure is different from stepping exposure. It uses uniform linear scanning of narrow sl...

AI Technical Summary

Problems solved by technology

[0004] The synchronization error between the mask stage and the wafer stage during the scanning exposure process will not only cause changes and misalignment of the pattern on the silicon wafer, but also reduce the contrast of the pattern, and eventually cause lithographic pattern defects

[0005] Usually, the synchronization error characteristics of a step-scan projection lithography machine are represented by the moving average error MA and the moving standard deviation MSD. The moving average deviation is the moving average of the synchronization deviation, which reflects the average deviation between the mask feature pattern and its ideal position. The deviation will lead to the overall dislocation of the exposure pattern, which will mainly affect the overlay accuracy of lithography in the process

The moving standard deviation is the mean square error of the synchronization deviation of all points in the aperture, which reflects the mean square error of the position jitter caused by the scanning asynchrony. This high-frequency transformation of the relative position of the mask stage and the wafer stage during the scanning exposure process will cause imaging Blur, will mainly affect the exposure resolution of lithography in the process

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