Overlay vernier pattern for measuring multi-layer overlay alignment accuracy and method for measuring the same

摘要

An overlay vernier pattern for measuring multi-layer overlay alignment accuracy and a method for measuring the same is provided. A distance between a first alignment mark in a first material layer and a second alignment mark in an underlying second material layer is measured, so as to provide an alignment offset between the first material layer and the second material layer. In addition, a distance between the second alignment mark in the second material layer and a third alignment mark in a third material layer underlying the second material layer is measured, so as to provide an alignment offset between the second material layer and the third material layer. Because the second alignment marks can be repeatedly used, scribe line areas for forming these alignment marks and measuring time are saved to increase the production throughput.