KLA Corporation
SYSTEM AMD METHOD FOR DETERMINING TARGET FEATURE FOCUS IN IMAGE-BASED OVERLAY METROLOGY

Abstract:

A metrology system includes one or more through-focus imaging metrology sub-systems communicatively coupled to a controller having one or more processors configured receive a plurality of training images captured at one or more focal positions. The one or more processors may generate a machine learning classifier based on the plurality of training images. The one or more processors may receive one or more target feature selections for one or more target overlay measurements corresponding to one or more target features. The one or more processors may determine one or more target focal positions based on the one or more target feature selections using the machine learning classifier. The one or more processors may receive one or more target images captured at the one or more target focal positions, the target images including the one or more target features of the target specimen, and determine overlay based thereon.