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Title: Method and apparatus for inspecting reflection masks for defects

Abstract

An at-wavelength system for extreme ultraviolet lithography mask blank defect detection is provided. When a focused beam of wavelength 13 nm is incident on a defective region of a mask blank, three possible phenomena can occur. The defect will induce an intensity reduction in the specularly reflected beam, scatter incoming photons into an off-specular direction, and change the amplitude and phase of the electric field at the surface which can be monitored through the change in the photoemission current. The magnitude of these changes will depend on the incident beam size, and the nature, extent and size of the defect. Inspection of the mask blank is performed by scanning the mask blank with 13 nm light focused to a spot a few .mu.m in diameter, while measuring the reflected beam intensity (bright field detection), the scattered beam intensity (dark-field detection) and/or the change in the photoemission current.

Inventors:
 [1];  [2]
  1. (Oakland, CA)
  2. (Berkeley, CA)
Issue Date:
Research Org.:
Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA
Sponsoring Org.:
USDOE
OSTI Identifier:
921275
Patent Number(s):
6,555,828
Application Number:
09/193,198
Assignee:
The Regents of the University of California (Oakland, CA) OAK
DOE Contract Number:  
AC03-76SF00098
Resource Type:
Patent
Country of Publication:
United States
Language:
English

Citation Formats

Bokor, Jeffrey, and Lin, Yun. Method and apparatus for inspecting reflection masks for defects. United States: N. p., 2003. Web.
Bokor, Jeffrey, & Lin, Yun. Method and apparatus for inspecting reflection masks for defects. United States.
Bokor, Jeffrey, and Lin, Yun. Tue . "Method and apparatus for inspecting reflection masks for defects". United States. https://www.osti.gov/servlets/purl/921275.
@article{osti_921275,
title = {Method and apparatus for inspecting reflection masks for defects},
author = {Bokor, Jeffrey and Lin, Yun},
abstractNote = {An at-wavelength system for extreme ultraviolet lithography mask blank defect detection is provided. When a focused beam of wavelength 13 nm is incident on a defective region of a mask blank, three possible phenomena can occur. The defect will induce an intensity reduction in the specularly reflected beam, scatter incoming photons into an off-specular direction, and change the amplitude and phase of the electric field at the surface which can be monitored through the change in the photoemission current. The magnitude of these changes will depend on the incident beam size, and the nature, extent and size of the defect. Inspection of the mask blank is performed by scanning the mask blank with 13 nm light focused to a spot a few .mu.m in diameter, while measuring the reflected beam intensity (bright field detection), the scattered beam intensity (dark-field detection) and/or the change in the photoemission current.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {2003},
month = {4}
}

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