Measurement of overlay offset in semiconductor processing

摘要

A system for overlay offset measurement in semiconductor manufacturing including a radiation source, a detector, and a calculation unit. The radiation source is operable to irradiate an overlay offset measurement target. The detector is operable to detect a first reflectivity and a second reflectivity of the irradiated overlay offset measurement target. The calculation unit is operable to determine an overlay offset using the detected first and second reflectivity by determining a predetermined overlay offset amount which provides an actual offset of zero.