KLA Corporation
Device-like overlay metrology targets displaying Moire effects

Abstract:

A metrology system and metrology methods are disclosed. The metrology system comprises a set of device features on a first layer of a sample, a first set of target features on a second layer of the sample and overlapping the set of device features, and a second set of target features on the second layer of the sample and overlapping the set of device features. Relative positions of a first set of Moire fringes and a second set of Moire fringes indicate overlay error between the first layer of the sample and the second layer of the sample.