公开(公告)号：US20240201073A1

公开(公告)日：2024-06-20

申请号：US18231688

申请日：2023-08-08

Applicant: KLA Corporation

Inventor： Shankar Krishnan ,  Kaichun Yang ,  Xi Chen

IPC: G01N21/21 ,  G01N21/956 ,  G01N21/958

CPC classification number: G01N21/211 ,  G01N21/956 ,  G01N21/958 ,  G01N2021/213

Abstract: Methods and systems for performing spectroscopic ellipsometry (SE) measurements of surface structures of optical elements fabricated on transparent substrates are presented herein. The SE measurement system is configured to detect light from the measured structures without contamination from light reflected from the backside surface of the transparent substrate. Surface structures of optical elements include film structures and grating structures fabricated on thin transparent substrates. The SE based measurement system is configured with a relatively large illumination Numerical Aperture (NA) and relatively high demagnification from the illumination source to the measurement spot on the optically transparent substrate. This configuration results in a relatively small measurement spot size and small depth of focus that minimizes the amount of light reflected from the backside of the optically transparent substrate. In addition, a relatively small collection aperture size further minimizes backside reflected light from reaching the detector.

公开(公告)号：US20240186191A1

公开(公告)日：2024-06-06

申请号：US18210571

申请日：2023-06-15

Applicant: KLA Corporation

Inventor： Ming Di ,  Qiang Zhao ,  Tianhao Zhang ,  Dawei Hu ,  Yih Chang ,  Xi Chen

IPC: H01L21/66 ,  G01J3/02 ,  G01J3/28

CPC classification number: H01L22/12 ,  G01J3/0229 ,  G01J3/2823

Abstract: Methods and systems for measuring values of one or more parameters of interest, including changes in values of one or more parameters of interest, based on measured spectral differences are presented herein. A trained spectral difference based measurement model determines changes in the values of one or more parameters of interest based on a measure of differences in spectra measured before and after one or more process steps. In some examples, a measure of spectral difference is determined based on a difference in measured intensity, a difference in harmonic signal values, or a difference in value of one or more Mueller Matrix elements. A measure of spectral difference may be expressed as a set of difference values, a scalar value, or coefficients of a functional fit to difference values. A measure of spectral difference may be determined based on a weighting of spectral differences according to wavelength.

公开(公告)号：US20240053280A1

公开(公告)日：2024-02-15

申请号：US18229606

申请日：2023-08-02

Applicant: KLA Corporation

Inventor： Ming Di ,  Yih-Chung Chang ,  Xi Chen ,  Dawei Hu ,  Ce Xu ,  Bowei Huang ,  Igor Baskin ,  Mark Allen Neil ,  Tianhao Zhang ,  Malik Karman Sadiq ,  Shankar Krishnan ,  Jenching Tsai ,  Carlos L. Ygartua ,  Yao-Chung Tsao ,  Qiang Zhao

IPC: G01N21/95 ,  H01L21/66

CPC classification number: G01N21/9501 ,  H01L22/12

Abstract: Methods and systems for compensating systematic errors across a fleet of metrology systems based on a trained error evaluation model to improve matching of measurement results across the fleet are described herein. In one aspect, the error evaluation model is a machine learning based model trained based on a set of composite measurement matching signals. Composite measurement matching signals are generated based on measurement signals generated by each target measurement system and corresponding model-based measurement signals associated with each target measurement system and reference measurement system. The training data set also includes an indication of whether each target system is operating within specification, an indication of the values of system model parameter of each target system, or both. In some embodiments, the composite measurement matching signals driving the training of the error evaluation model are weighted differently, for example, based on measurement sensitivity, measurement noise, or both.

公开(公告)号：US20240176206A1

公开(公告)日：2024-05-30

申请号：US18116187

申请日：2023-03-01

Applicant: KLA Corporation

Inventor： Qiang Zhao ,  Ming Di ,  Xi Chen ,  Shova Subedi ,  Tianhao Zhang

IPC: G02F1/35 ,  G01N21/63 ,  G01N21/95

CPC classification number: G02F1/3532 ,  G01N21/636 ,  G01N21/9501 ,  G01N2021/0125

Abstract: A metrology system may include an illumination source to generate an illumination beam and an illumination sub-system to direct the illumination beam to a sample with an inversion-symmetric substrate and one or more films disposed on the inversion-symmetric substrate. The system may further include a filter configured to block a wavelength of the illumination beam and pass a wavelength associated with a second harmonic of the illumination beam and a detector to capture second harmonic generation (SHG) light. The system may further include a controller to receive metrology data from the detector associated with the SHG light from with an interface between the inversion-symmetric substrate and the one or more films and generate one or more metrology measurements associated with the one or more films based on the metrology data.