METHODS FOR MONITORING SOURCE SYMMETRY OF PHOTOLITHOGRAPHY SYSTEMS

摘要

A method for monitoring the source symmetry of a photolithography system is provided. The method includes providing a first reticle; and providing a second reticle. The method also includes forming first bottom overlay alignment marks on a first wafer using the first reticle; and forming first top overlay alignment marks on the first bottom overlay alignment marks using the second reticle. Further, the method includes forming second bottom overlay alignment marks on a second wafer using the first reticle; and forming second top overlay alignment marks on the second bottom overlay alignment marks using the second reticle. Further, the method also include measuring a first overlay shift; measuring a second overlay shift; and obtaining an overlay shift caused by the source asymmetry based on the first overlay shift and the second overlay shift.

主权项

1. A method for monitoring the source symmetry of a photolithography system, comprising:
providing a first reticle having a plurality of first mark patterns and a plurality of second mark patterns; providing a second reticle having a plurality of the first mark patterns and a plurality of second mark patterns; forming first bottom overlay alignment marks on a first wafer using the first reticle; forming first top overlay alignment marks on the first bottom overlay alignment marks using the second reticle; forming second bottom overlay alignment marks on a second wafer using the first reticle; forming second top overlay alignment marks on the second bottom overlay alignment marks using the second reticle; measuring a first overlay shift of the first top overlay alignment marks and the first bottom overlay alignment marks; measuring a second overlay shift of the second top overlay alignment marks and the second bottom overlay alignment marks; and obtaining an overlay shift caused by the source asymmetry based on the first overlay shift and the second overlay shift.