公开(公告)号：US20240085321A1

公开(公告)日：2024-03-14

申请号：US18136739

申请日：2023-04-19

Applicant: KLA Corporation

Inventor： John Hench ,  Akshay Krishna ,  Christopher Liman ,  Jeremy Smith ,  Liang Yin ,  Hyowon Park ,  Tianhan Wang ,  Boxue Chen

IPC: G01N21/47

CPC classification number: G01N21/4738

Abstract: Methods and systems for performing model-less measurements of semiconductor structures based on scatterometry measurement data are described herein. Scatterometry measurement data is processed directly, without the use of a traditional measurement model. Measurement sensitivity is defined by the changes in detected diffraction images at one or more non-zero diffraction orders over at least two different illumination incidence angles. Discrete values of a scalar function are determined directly from measured images at each incidence angle. A continuous mathematical function is fit to the set of discrete values of the scalar function determined at each incidence angle. A value of a parameter of interest is determined based on analysis of the mathematical function. In some embodiments, the scalar function includes a weighting function, and the weighting values associated with weighting function are optimized to yield an accurate fit of the mathematical function to the scalar values.