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Title: Extreme-UV lithography system

Abstract

A photolithography system that employs a condenser that includes a series of aspheric mirrors on one side of a small, incoherent source of radiation producing a series of beams is provided. Each aspheric mirror images the quasi point source into a curved line segment. A relatively small arc of the ring image is needed by the camera; all of the beams are so manipulated that they all fall onto this same arc needed by the camera. Also, all of the beams are aimed through the camera's virtual entrance pupil. The condenser includes a correcting mirror for reshaping a beam segment which improves the overall system efficiency. The condenser efficiently fills the larger radius ringfield created by today's advanced camera designs. The system further includes (i) means for adjusting the intensity profile at the camera's entrance pupil or (ii) means for partially shielding the illumination imaging onto the mask or wafer. The adjusting means can, for example, change at least one of: (i) partial coherence of the photolithography system, (ii) mask image illumination uniformity on the wafer or (iii) centroid position of the illumination flux in the entrance pupil. A particularly preferred adjusting means includes at least one vignetting mask thatmore » covers at least a portion of the at least two substantially equal radial segments of the parent aspheric mirror.« less

Inventors:
 [1];  [2]
  1. (Livermore, CA)
  2. (Albuquerque, NM)
Issue Date:
Research Org.:
SANDIA CORP
OSTI Identifier:
873699
Patent Number(s):
6225027
Assignee:
EUV LLC (Livermore, CA) SNL
DOE Contract Number:  
AC04-94AL85000
Resource Type:
Patent
Country of Publication:
United States
Language:
English
Subject:
extreme-uv; lithography; photolithography; employs; condenser; series; aspheric; mirrors; incoherent; source; radiation; producing; beams; provided; mirror; images; quasi; curved; line; segment; relatively; image; camera; manipulated; fall; aimed; virtual; entrance; pupil; correcting; reshaping; beam; improves; overall; efficiency; efficiently; fills; larger; radius; ringfield; created; advanced; designs; means; adjusting; intensity; profile; ii; partially; shielding; illumination; imaging; mask; wafer; example; change; partial; coherence; uniformity; iii; centroid; position; flux; particularly; preferred; vignetting; covers; portion; substantially; equal; radial; segments; parent; particularly preferred; mask image; extreme-uv lithography; entrance pupil; substantially equal; intensity profile; beam segment; parent aspheric; mirror images; field created; aspheric mirrors; aspheric mirror; incoherent source; mirror image; coherent source; correcting mirror; /430/359/378/

Citation Formats

Replogle, William C., and Sweatt, William C. Extreme-UV lithography system. United States: N. p., 2001. Web.
Replogle, William C., & Sweatt, William C. Extreme-UV lithography system. United States.
Replogle, William C., and Sweatt, William C. Mon . "Extreme-UV lithography system". United States. https://www.osti.gov/servlets/purl/873699.
@article{osti_873699,
title = {Extreme-UV lithography system},
author = {Replogle, William C. and Sweatt, William C.},
abstractNote = {A photolithography system that employs a condenser that includes a series of aspheric mirrors on one side of a small, incoherent source of radiation producing a series of beams is provided. Each aspheric mirror images the quasi point source into a curved line segment. A relatively small arc of the ring image is needed by the camera; all of the beams are so manipulated that they all fall onto this same arc needed by the camera. Also, all of the beams are aimed through the camera's virtual entrance pupil. The condenser includes a correcting mirror for reshaping a beam segment which improves the overall system efficiency. The condenser efficiently fills the larger radius ringfield created by today's advanced camera designs. The system further includes (i) means for adjusting the intensity profile at the camera's entrance pupil or (ii) means for partially shielding the illumination imaging onto the mask or wafer. The adjusting means can, for example, change at least one of: (i) partial coherence of the photolithography system, (ii) mask image illumination uniformity on the wafer or (iii) centroid position of the illumination flux in the entrance pupil. A particularly preferred adjusting means includes at least one vignetting mask that covers at least a portion of the at least two substantially equal radial segments of the parent aspheric mirror.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {2001},
month = {1}
}

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