OSA's Digital Library

Applied Optics

Applied Optics

APPLICATIONS-CENTERED RESEARCH IN OPTICS

  • Editor: Joseph N. Mait
  • Vol. 53, Iss. 14 — May. 10, 2014
  • pp: 3075–3080

Corrective finishing of extreme ultraviolet photomask blanks by precessed bonnet polisher

Anthony Beaucamp, Yoshiharu Namba, and Phillip Charlton  »View Author Affiliations


Applied Optics, Vol. 53, Issue 14, pp. 3075-3080 (2014)
http://dx.doi.org/10.1364/AO.53.003075


View Full Text Article

Enhanced HTML    Acrobat PDF (1119 KB)





Browse Journals / Lookup Meetings

Browse by Journal and Year


   


Lookup Conference Papers

Close Browse Journals / Lookup Meetings

Article Tools

Share
Citations

Abstract

The progressive transition from Excimer to extreme ultraviolet (EUV) lithography is driving a need for flatter and smoother photomask blanks. It is, however, proving difficult to meet the next-generation specification with the conventional chemical mechanical polishing technology commonly used for finishing photomask blanks. This paper reports on the application of subaperture computer numerical control precessed bonnet polishing technology to the corrective finishing of photomask substrates for EUV lithography. Full-factorial analysis was used to identify process parameters capable of delivering microroughness below 0.5 nm rms while retaining relatively high removal rates. Experimental results show that masks prepolished to 300–600 nm peak-to-valley (P-V) flatness by chemical/mechanical polishing can then be improved down to 50–100 nm P-V flatness using the automated technology described in this paper. A series of edge polishing experiments also hints at the possibility of increasing the quality area beyond the 142 mm square defined in the official EUV photomask specification.

© 2014 Optical Society of America

OCIS Codes
(220.3740) Optical design and fabrication : Lithography
(220.5450) Optical design and fabrication : Polishing
(340.7480) X-ray optics : X-rays, soft x-rays, extreme ultraviolet (EUV)

ToC Category:
Optical Design and Fabrication

History
Original Manuscript: March 4, 2014
Revised Manuscript: April 3, 2014
Manuscript Accepted: April 4, 2014
Published: May 8, 2014

Citation
Anthony Beaucamp, Yoshiharu Namba, and Phillip Charlton, "Corrective finishing of extreme ultraviolet photomask blanks by precessed bonnet polisher," Appl. Opt. 53, 3075-3080 (2014)
http://www.opticsinfobase.org/ao/abstract.cfm?URI=ao-53-14-3075


Sort:  Author  |  Year  |  Journal  |  Reset  

References

  1. The Global Micropatterning Committee, “Specification for extreme ultraviolet lithography mask substrates,” (2010), pp. 1–10.
  2. T. Shoki, M. Mitsui, M. Sakamoto, N. Sakaya, M. Ootsuka, T. Asakawa, and H. Mitsui, “Improvement of total quality on EUV mask blanks toward volume production,” Proc. SPIE 7636, 76360U (2010). [CrossRef]
  3. Y. Hirabayashi, “Development status of EUVL mask blank and substrate,” Proc. SPIE 8166, 81663T (2011). [CrossRef]
  4. A. Beaucamp, Y. Namba, I. Inasaki, and R. Freeman, “Finishing of optical molds to λ/20 by automated corrective polishing,” Ann. CIRP 60, 375–378 (2011). [CrossRef]
  5. D. Walker, R. Freeman, and A. Beaucamp, “Use of the precessions process for prepolishing and correcting form,” Opt. Express 14, 11787–11795 (2006). [CrossRef]
  6. A. Beaucamp and Y. Namba, “Super-smooth finishing of diamond turned hard X-ray molding dies by combined fluid jet and bonnet polishing,” Ann. CIRP 62, 315–318 (2013). [CrossRef]
  7. C. King, “New approach to stitching optical metrology data,” Ph.D dissertation (University College London, 2008).
  8. W. Wang, M. Xu, G. Yu, D. Walker, and H. Zhu, “Research on edge control in the process of polishing using ultra precise bonnet on optical elements,” Proc. SPIE 7654, 76540N (2010). [CrossRef]
  9. D. Walker, G. Yu, A. Beaucamp, and W. Messelink, “Edges in CNC polishing: from mirror segments towards semiconductors,” Opt. Express 20, 19787–19798 (2012). [CrossRef]
  10. H. Li, D. Walker, G. Yu, A. Sayle, W. Messelink, R. Evans, and A. Beaucamp, “Edge control in CNC polishing: simulation and validation of tool influence functions on edges,” Opt. Express 21, 370–381 (2013). [CrossRef]
  11. L. Cook, “Chemical processes in glass polishing,” J. Non-Cryst. Solids 120, 152–171 (1990). [CrossRef]

Cited By

Alert me when this paper is cited

OSA is able to provide readers links to articles that cite this paper by participating in CrossRef's Cited-By Linking service. CrossRef includes content from more than 3000 publishers and societies. In addition to listing OSA journal articles that cite this paper, citing articles from other participating publishers will also be listed.


« Previous Article  |  Next Article »

OSA is a member of CrossRef.

CrossCheck Deposited