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Title: Critical illumination condenser for x-ray lithography

Abstract

A critical illumination condenser system, particularly adapted for use in extreme ultraviolet (EUV) projection lithography based on a ring field imaging system and a laser produced plasma source. The system uses three spherical mirrors and is capable of illuminating the extent of the mask plane by scanning either the primary mirror or the laser plasma source. The angles of radiation incident upon each mirror of the critical illumination condenser vary by less than eight (8) degrees. For example, the imaging system in which the critical illumination condenser is utilized has a 200 .mu.m source and requires a magnification of 26.times.. The three spherical mirror system constitutes a two mirror inverse Cassegrain, or Schwarzschild configuration, with a 25% area obstruction (50% linear obstruction). The third mirror provides the final pupil and image relay. The mirrors include a multilayer reflective coating which is reflective over a narrow bandwidth.

Inventors:
 [1];  [2]
  1. (Pleasanton, CA)
  2. (Livermore, CA)
Issue Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
OSTI Identifier:
871460
Patent Number(s):
5737137
Assignee:
Regents of University of California (Oakland, CA) LLNL
DOE Contract Number:  
W-7405-ENG-48
Resource Type:
Patent
Country of Publication:
United States
Language:
English
Subject:
critical; illumination; condenser; x-ray; lithography; particularly; adapted; extreme; ultraviolet; euv; projection; based; field; imaging; laser; produced; plasma; source; spherical; mirrors; capable; illuminating; extent; mask; plane; scanning; primary; mirror; angles; radiation; incident; vary; eight; degrees; example; utilized; 200; requires; magnification; 26; times; constitutes; inverse; cassegrain; schwarzschild; configuration; 25; obstruction; 50; linear; third; provides; final; pupil; image; relay; multilayer; reflective; coating; narrow; bandwidth; multilayer reflective; narrow bandwidth; reflective coating; laser produced; primary mirror; laser plasma; projection lithography; x-ray lithography; particularly adapted; plasma source; extreme ultraviolet; radiation incident; narrow band; spherical mirror; spherical mirrors; third mirror; critical illumination; illumination condenser; produced plasma; /359/355/378/

Citation Formats

Cohen, Simon J., and Seppala, Lynn G. Critical illumination condenser for x-ray lithography. United States: N. p., 1998. Web.
Cohen, Simon J., & Seppala, Lynn G. Critical illumination condenser for x-ray lithography. United States.
Cohen, Simon J., and Seppala, Lynn G. Thu . "Critical illumination condenser for x-ray lithography". United States. https://www.osti.gov/servlets/purl/871460.
@article{osti_871460,
title = {Critical illumination condenser for x-ray lithography},
author = {Cohen, Simon J. and Seppala, Lynn G.},
abstractNote = {A critical illumination condenser system, particularly adapted for use in extreme ultraviolet (EUV) projection lithography based on a ring field imaging system and a laser produced plasma source. The system uses three spherical mirrors and is capable of illuminating the extent of the mask plane by scanning either the primary mirror or the laser plasma source. The angles of radiation incident upon each mirror of the critical illumination condenser vary by less than eight (8) degrees. For example, the imaging system in which the critical illumination condenser is utilized has a 200 .mu.m source and requires a magnification of 26.times.. The three spherical mirror system constitutes a two mirror inverse Cassegrain, or Schwarzschild configuration, with a 25% area obstruction (50% linear obstruction). The third mirror provides the final pupil and image relay. The mirrors include a multilayer reflective coating which is reflective over a narrow bandwidth.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1998},
month = {1}
}

Patent:

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