LITHOGRAPHIC APPARATUS, METROLOGY SYSTEM, AND INTENSITY IMBALANCE MEASUREMENT FOR ERROR CORRECTION

摘要

A metrology system includes a beam splitter and first and second sensors. The beam splitter splits scattered radiation scattered by a target into first and second portions of radiation. The first sensor receives the first portion. The second sensor receives (he second portion after the second portion propagates along a path that includes a wedge system comprising a first wedge configured to diverge the second portion.