skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Evaluating EUV mask pattern imaging with two EUV microscopes

Abstract

Aerial image measurement plays a key role in the development of patterned reticles for each generation of lithography. Studying the field transmitted (reflected) from EUV masks provides detailed information about potential disruptions caused by mask defects, and the performance of defect repair strategies, without the complications of photoresist imaging. Furthermore, by measuring the continuously varying intensity distribution instead of a thresholded, binary resist image, aerial image measurement can be used as feedback to improve mask and lithography system modeling methods. Interest in EUV, at-wavelength, aerial image measurement lead to the creation of several research tools worldwide. These tools are used in advanced mask development work, and in the evaluation of the need for commercial at-wavelength inspection tools. They describe performance measurements of two such tools, inspecting the same EUV mask in a series of benchmarking tests that includes brightfield and darkfield patterns. One tool is the SEMATECH Berkeley Actinic Inspection Tool (AIT) operating on a bending magnet beamline at Lawrence Berkeley National Laboratory's Advanced Light Source. The AIT features an EUV Fresnel zoneplate microscope that emulates the numerical aperture of a 0.25-NA stepper, and projects the aerial image directly onto a CCD camera, with 700x magnification. The second tool ismore » an EUV microscope (EUVM) operating at the NewSUBARU synchrotron in Hyogo, Japan. The NewSUBARU tool projects the aerial image using a reflective, 30x Schwarzschild objective lens, followed by a 10-200x x-ray zooming tube. The illumination conditions and the imaging etendue are different for the two tools. The benchmarking measurements were used to determine many imaging and performance properties of the tools, including resolution, modulation transfer function (MTF), aberration magnitude, aberration field-dependence (including focal-plane tilt), illumination uniformity, line-edge roughness, and flare. These measurements reveal the current state of the art in at-wavelength inspection performance, and will be a useful reference as performance improves over time.« less

Authors:
; ; ; ; ; ;
Publication Date:
Research Org.:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org.:
Materials Sciences Division
OSTI Identifier:
943591
Report Number(s):
LBNL-1267E-Ext-Abs
TRN: US0900492
DOE Contract Number:  
DE-AC02-05CH11231
Resource Type:
Conference
Resource Relation:
Conference: SPIE EmergingLithographic Technologies XII, San Jose, CA, February 26-28, 2008
Country of Publication:
United States
Language:
English
Subject:
36; ADVANCED LIGHT SOURCE; APERTURES; BENDING; DEFECTS; DISTRIBUTION; FEEDBACK; ILLUMINANCE; MAGNETS; MICROSCOPES; MODULATION; REPAIR; RESOLUTION; ROUGHNESS; SYNCHROTRONS; TRANSFER FUNCTIONS; Evaluating EUV microscopes

Citation Formats

Goldberg, Kenneth A, Takase, Kei, Naulleau, Patrick P, Han, Hakseung, Barty, Anton, Kinoshita, Hiroo, and Hamamoto, Kazuhiro. Evaluating EUV mask pattern imaging with two EUV microscopes. United States: N. p., 2008. Web.
Goldberg, Kenneth A, Takase, Kei, Naulleau, Patrick P, Han, Hakseung, Barty, Anton, Kinoshita, Hiroo, & Hamamoto, Kazuhiro. Evaluating EUV mask pattern imaging with two EUV microscopes. United States.
Goldberg, Kenneth A, Takase, Kei, Naulleau, Patrick P, Han, Hakseung, Barty, Anton, Kinoshita, Hiroo, and Hamamoto, Kazuhiro. Tue . "Evaluating EUV mask pattern imaging with two EUV microscopes". United States. https://www.osti.gov/servlets/purl/943591.
@article{osti_943591,
title = {Evaluating EUV mask pattern imaging with two EUV microscopes},
author = {Goldberg, Kenneth A and Takase, Kei and Naulleau, Patrick P and Han, Hakseung and Barty, Anton and Kinoshita, Hiroo and Hamamoto, Kazuhiro},
abstractNote = {Aerial image measurement plays a key role in the development of patterned reticles for each generation of lithography. Studying the field transmitted (reflected) from EUV masks provides detailed information about potential disruptions caused by mask defects, and the performance of defect repair strategies, without the complications of photoresist imaging. Furthermore, by measuring the continuously varying intensity distribution instead of a thresholded, binary resist image, aerial image measurement can be used as feedback to improve mask and lithography system modeling methods. Interest in EUV, at-wavelength, aerial image measurement lead to the creation of several research tools worldwide. These tools are used in advanced mask development work, and in the evaluation of the need for commercial at-wavelength inspection tools. They describe performance measurements of two such tools, inspecting the same EUV mask in a series of benchmarking tests that includes brightfield and darkfield patterns. One tool is the SEMATECH Berkeley Actinic Inspection Tool (AIT) operating on a bending magnet beamline at Lawrence Berkeley National Laboratory's Advanced Light Source. The AIT features an EUV Fresnel zoneplate microscope that emulates the numerical aperture of a 0.25-NA stepper, and projects the aerial image directly onto a CCD camera, with 700x magnification. The second tool is an EUV microscope (EUVM) operating at the NewSUBARU synchrotron in Hyogo, Japan. The NewSUBARU tool projects the aerial image using a reflective, 30x Schwarzschild objective lens, followed by a 10-200x x-ray zooming tube. The illumination conditions and the imaging etendue are different for the two tools. The benchmarking measurements were used to determine many imaging and performance properties of the tools, including resolution, modulation transfer function (MTF), aberration magnitude, aberration field-dependence (including focal-plane tilt), illumination uniformity, line-edge roughness, and flare. These measurements reveal the current state of the art in at-wavelength inspection performance, and will be a useful reference as performance improves over time.},
doi = {},
url = {https://www.osti.gov/biblio/943591}, journal = {},
number = ,
volume = ,
place = {United States},
year = {2008},
month = {2}
}

Conference:
Other availability
Please see Document Availability for additional information on obtaining the full-text document. Library patrons may search WorldCat to identify libraries that hold this conference proceeding.

Save / Share: