公开(公告)号：US11060982B2

公开(公告)日：2021-07-13

申请号：US16815362

申请日：2020-03-11

Applicant: KLA Corporation

Inventor： Natalia Malkova ,  Mikhail Sushchik ,  Dawei Hu ,  Carlos L. Ygartua

IPC: G01N21/95 ,  G01B11/06 ,  G01N21/956 ,  G06T7/00

Abstract: Methods and systems for estimating values of parameters of interest from optical measurements of a sample early in a production flow based on a multidimensional optical dispersion (MDOD) model are presented herein. An MDOD model describes optical dispersion of materials comprising a structure under measurement in terms of parameters external to a base optical dispersion model. In some examples, a power law model describes the physical relationship between the external parameters and a parameter of the base optical dispersion model. In some embodiments, one or more external parameters are treated as unknown values that are resolved based on spectral measurement data. In some embodiments, one or more external parameters are treated as known values, and values of base optical dispersion model parameters, one or more external parameters having unknown values, or both, are resolved based on spectral measurement data and the known values of the one or more external parameters.

公开(公告)号：US11060846B2

公开(公告)日：2021-07-13

申请号：US16660492

申请日：2019-10-22

Applicant: KLA Corporation

Inventor： Houssam Chouaib ,  Aaron Rosenberg ,  Kai-Hsiang Lin ,  Dawei Hu ,  Zhengquan Tan

IPC: G01B11/06 ,  G03F7/20 ,  G01N21/956 ,  H01L29/10

Abstract: Methods and systems for measuring optical properties of transistor channel structures and linking the optical properties to the state of strain are presented herein. Optical scatterometry measurements of strain are performed on metrology targets that closely mimic partially manufactured, real device structures. In one aspect, optical scatterometry is employed to measure uniaxial strain in a semiconductor channel based on differences in measured spectra along and across the semiconductor channel. In a further aspect, the effect of strain on measured spectra is decorrelated from other contributors, such as the geometry and material properties of structures captured in the measurement. In another aspect, measurements are performed on a metrology target pair including a strained metrology target and a corresponding unstrained metrology target to resolve the geometry of the metrology target under measurement and to provide a reference for the estimation of the absolute value of strain.