公开(公告)号：US09760018B2

公开(公告)日：2017-09-12

申请号：US14906898

申请日：2014-08-05

Applicant: ASML Netherlands B.V.

Inventor： Seyed Iman Mossavat ,  Hugo Augustinus Joseph Cramer ,  Willem Jan Grootjans ,  Adriaan Johan Van Leest

IPC: G01B11/04 ,  G01N21/00 ,  G03B27/32 ,  G03B27/74 ,  G03F7/20 ,  G01N21/956 ,  G03F9/00

CPC classification number: G03F7/705 ,  G01N21/956 ,  G01N21/95607 ,  G03F7/70625 ,  G03F9/7092

Abstract: Methods and inspection apparatus and computer program products for assessing a quality of reconstruction of a value of a parameter of interest of a structure, which may be applied for example in metrology of microscopic structures. It is important the reconstruction provides a value of a parameter of interest (e.g. a CD) of the structure which is accurate as the reconstructed value is used to monitor and/or control a lithographic process. This is a way of assessing a quality of reconstruction (803) of a value of a parameter of interest of a structure which does not require the use of a scanning electron microscope, by predicting (804) values of the parameter of interest of structures using reconstructed values of parameters of structures, and by comparing (805) the predicted values of the parameter of interest and the reconstructed values of the parameter of interest.

公开(公告)号：US08994944B2

公开(公告)日：2015-03-31

申请号：US14149723

申请日：2014-01-07

Applicant: ASML Netherlands B.V.

Inventor： Hugo Augustinus Joseph Cramer ,  Arie Jeffrey Den Boef ,  Henricus Johannes Lambertus Megens ,  Hendrik Jan Hidde Smilde ,  Adrianus Johannes Hendrikus Schellekens ,  Michael Kubis

IPC: G01B11/00 ,  G01B11/24 ,  G01B11/02 ,  G03F7/20 ,  G01N21/88

CPC classification number: G03F7/70641 ,  G01B11/02 ,  G01B11/22 ,  G01B11/24 ,  G01B11/30 ,  G01N21/47 ,  G01N21/88 ,  G03F7/70608 ,  G03F7/70625 ,  G03F7/70633 ,  G03F7/7065

Abstract: In a method of determining the focus of a lithographic apparatus used in a lithographic process on a substrate, the lithographic process is used to form a structure on the substrate, the structure having at least one feature which has an asymmetry in the printed profile which varies as a function of the focus of the lithographic apparatus on the substrate. A first image of the periodic structure is formed and detected while illuminating the structure with a first beam of radiation. The first image is formed using a first part of non-zero order diffracted radiation. A second image of the periodic structure is formed and detected while illuminating the structure with a second beam of radiation. The second image is formed using a second part of the non-zero order diffracted radiation which is symmetrically opposite to the first part in a diffraction spectrum. The ratio of the intensities of the measured first and second portions of the spectra is determined and used to determine the asymmetry in the profile of the periodic structure and/or to provide an indication of the focus on the substrate. In the same instrument, an intensity variation across the detected portion is determined as a measure of process-induced variation across the structure. A region of the structure with unwanted process variation can be identified and excluded from a measurement of the structure.