Okazaki’s contribution to the lithography
Shinji Okazaki made pioneering contributions in resolution enhanced optical lithography and high-throughput electron-beam (EB) direct writing technology. Until the early 1990’s, it was a general belief that the resolution in optical lithography could be improved only by employing either a shorter exposure wavelength or a lens system with higher numerical aperture. While working at Hitachi’s Central Research Laboratory, he and his group proposed half-tone (attenuated) masks and chrome-less phase-shifting techniques (6, 7, 9), to demonstrate there is a way around. They were awarded with the IEEE Paul Rappaport Award (6) in 1991. Moreover, they proposed the use of anti-reflective coating on resist layer to reduce line width variations, which is one of the most important issues in critical dimensions below 100 nm. These technologies that he led to develop are widely used today in fabricating modern VLSI devices (3, 12, 14-17).
Okazaki made important contributions in EB direct-writing technology, too. He and his group drastically increased the throughput by proposing the cell-projection exposure scheme (2), which was successfully implemented in Hitachi’s HL-Series EB Exposure Products (8). Most of EB system suppliers these days use this scheme in their products. Swelling-free resist materials that his team developed, coupled with the chemical amplification scheme, are also widely used in EB lithography (4,5).
Shinji Okazaki is one of engineers with highest accomplishment in the field of lithography for microelectronics. His creativity has been well recorded in more than 150 papers presented in major journals and at international conferences, more than 50 invited/plenary talks and short course lectures, and 7 books and book chapters, which have materialized during his career. His leadership is evidenced by the achievements of the groups he has led. He has also made contributions in SPIE conference activities such as a plenary speaker, invited speaker, and session chairs .
Okazaki also contributed to the Next Generation Lithography (NGL) Workshop sponsored by International SEMATECH since 1997 till 2001 as a task force member and the technical champion of EUV lithography. He co-chaired the International EUVL Symposium sponsored International SEMATECH, ASET and MEDEA since 2003. He was a member of Japanese lithography working group in the International Technology Roadmap for Semiconductors (ITRS). In addition, he was a leader of the working group in the SEMI standard committee for the standardization of the half-tone (attenuated) phase shifting technique.
Evidence of technical contribution
(1) Since 1998, Dr. Okazaki has led EUV lithography at ASET, an consortium in the Japanese semiconductor industry sponsored by the Japanese government. ASET is being run in cooperation with other entities such as International SEMATECH, IMEC and LETI. To promote interactions among these organizations Okazaki has organized a series of international workshops and symposia between since 1999.
(2) Okazaki has participated in various committees at government agencies such as NEDO, JSPS and FED for the investigation of the new technologies. He is an active member of Technical Working Group of Semiconductor Technology Roadmap of Japan (STRJ).
(3) He taught a course, “VLSI Process Technology” for 6 years at Tokyo Institute of Technology, and “Fine Patterning Technology” at Osaka University for ４years and “Lithography for VLSI” at Tokyo Institute of Technology, Waseda University.
He also taught a course of “English for Engineers” at Nihon Institute of Technology for 4 years. He has been making lectures of lithography in the course of “Nano-Micro Engineering” at the graduate school of TokyoUniversity for 4years.
At National Institute of Advanced Industrial Science and Technology, he has been giving courses for micro-fabrication for more than 8 years.
Publications （Major 10 Articles）
(1) S. Okazaki, ‘Resolution limits of optical lithography,’ Plenary Talk at Int. Symp. on Electron, Ion and Photon Beams and Nanotechnology ’90, J. Vac. Sci. Technol. B9(6), Nov/Dec pp.2829-2833 (1990) (Leader. Proposal of various resolution enhancement techniques without recourse to shorter wavelengths.)
(2) Y. Nakayama, S. Okazaki, N. Saitou and H. Wakabayashi, ‘Electron beam cell projection lithography: A new high throughput electron beam direct writing technology using a specially tailored Si apertures,’ J. Vac. Sci. Technol. B8, N0.6 pp.1836-1840
(Leader. The first paper on Cell Projection technology.)
(3) T. Tanaka, N. Hasegawa, H. Shiraishi and S. Okazaki, ‘A New Photolithography Technique with Antireflective Coating on
Resist: ARCOR ,’ J. Electrochemical Soc. 137, pp.3900-3905 (1991)
(Leader. The first paper on antireflective coating for reducing linewidth variations.)
(4) S. Okazaki, F. Murai, O. Suga, H. Shiraishi and S. Koibuchi, ‘A Practical electron beam direct writing process technology for submicron device fabrication,’ J. Vac. Sci. Technol. B5(1), pp.402-404 (1987)
(Leader. The first swelling free EB resist process)
(5) O. Suga, E. Aoki, S. Okazaki, F. Murai, H. Shiraishi and S. Nonogaki, ‘A new contrast enhancement technique for electron beam lithography,’ J. Vac. Sci. Technol. B6(1) pp.366-369 (1989) (Leader. Proposal of non-liner development for swelling free EB resist.)
(6) H. Fukuda, A. Imai, T. Terasawa and S. Okazaki, ‘New Approach to Resolution Limit and Advanced Image Formation
Techniques in Optical Lithography,’ IEEE ED Vol.38, No.1, pp.67-75 (1991)
(Leader. Analysis of resolution limits in optical lithography. Paul Rappaport Award winner)
(7) T. Tanaka, S. Uchino, N. Hasegawa, T. Yamanaka, T. Terasawa and S. Okazaki, ‘A Novel Optical Lithography Technique Using the Phase-Shifting Fringe,’ Jap. J. Appl. Phys. Vol. 30, No. 5, pp.1131-1136 (1991)
(Leader. The first chromeless phase-shifting technique)
(8) Y. Sakitani, H. Yoda, H. Todokoro, Y. Shibata, T. Yamazaki, K. Ohbitu, N. Saitou, S. Moriyama, S. Okazaki, G. Matsuoka, F. Murai and M. Okumura,’ Electron-beam cell projection lithography system,’ J. Vac. Sci. Technol. B10(6) pp.2759-2763 (1992)
(Co-author, The first demonstration of Cell Projection electron beam lithography system)
(9) T. Terasawa and S. Okazaki, ‘Phase-Shifting Technology for ULSI Patterning,’ Invited, IEICE Trans. Electron., No.1 pp.19-25 (1993) (Leader. Review of phase-shifting technology)
10) S. Okazaki, ‘EUV lithography program at ASET’, Proc. of SPIE No.3676 p238
(Leader, Introduction of New EUVL Program)
11) T. Ito and S. Okazaki, ‘Pushing the limits of lithography,’ Invited, Nature Vol. 406, No. 6799, pp1027-1031, 31 August 2000 (2000)
(Co-author. Guidelines for the future lithography)
Invited Talks
(12) S. Okazaki, ‘Comparison of Optical, X-ray, Electron and Ion Beam Lithography,’ 1988 Microelectronic Engineering ’88
(13) S. Okazaki, ‘Current Status and Future of ULSI Lithography,’ SSDM 1990
(14) S. Okazaki, N. Hasegawa and A. Imai, ‘Phase Shift Reticles,’ IEDM’91 (Principle author)
(15) S. Okazaki, ‘Lithography for ULSI,’ Plenary talk, SPIE Microlithography Symposium 1995
(16) S. Okazaki, ‘Optical Lithography, a never-ending lithography technology for ULSI fabrication,’ International Conference on Advanced Microelectronic Devices and Processing.
(17) S. Okazaki, ‘Lithographic Technologies for 1-Gb DRAMs and beyond,’ Ext. Abstract of SSDM ‘96
(18) S. Okazaki, ‘Lithography prospects for 0.18um technology and beyond,’ IEDM ’96
(19) S. Okazaki, ‘EUV lithography research program at ASET’, SPIE Microlithography Symposium 1999
(20) S. Okazaki, ‘Status of EUV Lithography Development at ASET,’ IEEE Lithography Workshop 2002.
Invited Talks & Papers
(1) 1991S. Okazaki, ‘Optical lithography using phase-shifting technology,’ OYO BUTURI Vol. 60, No.11 pp.1076-1086
(2) 1993S. Okazaki, ‘A Perspective on Ultra-Fine Lithographic Technology,’ FED Journal Vol.3, Suppl. 1, pp21-27
(3) 1994S. Okazaki, K. Kasama, H. Yasuda, S. Ohki and M. Nakase, ‘Lithography,’ J. IEICE Vol. 77 No.11 pp.1092-1108
(4) 1999 S. Okazaki, ‘EUV lithography program at ASET’, Proc. of SPIE No.3676 p238
(5) 1999 S. Okazaki, ‘Lithography Applications of SR Light,’ School of Applied Physics, Spring Meeting, Japan Society of Applied Physics
(6) 1999 S. Okazaki, ‘EUV Development Program in Japan,’ Int. Conf. on Electron, Ion and Photon Beam Technology and Nanofabrication
(7) 1999 S. Okazaki, ‘Future of Optical Lithography,’ 18th Congress of the International Commission for Optics, Tech. Digest pp.328-329
(8) 2001 S. Okazaki, ‘ASET development activities for lithographic technologies,’ 27th Int. Conf. Micro- and Nano Engineering, Microelecronic Engineering Vol.61/62 p. 9 (2002)
(9) 2002 S. Okazaki, ‘Recent development activities on EUVL at ASET’, Photo Mask Japan 2002
(10) 2004 S. Okazaki, ‘Recent Development Activities and Future Plans of EUV Lithography in Japan,’ Optics East 2004
(11) 2004 S. Okazaki, ‘Japanese EUVL Program’, 2nd European EUVL Workshop
(12) 2004 S. Okazaki, ‘Current issues and future prospects of lithography’, WOFE 2004
(13) 2004 S. Okazaki, ’Recent Activities on Maskless Lithography in Japan’, ISMT ML-2 Meeting
(14) 2004 S. Okazaki, ‘Status of EUV Lithography Development at ASET’, IEEE Lithography WS
(15) 2004 S. Okazaki, ‘The recent development activities on EUVL; the role of Japanese Consortia’, IFST 2004 The 7th International Forum on Semiconductor Technology
Books
(1) 1986Semiconductor Process Technology, Nikkei McGraw-Hill (Japanese, Chapter author)
(2) 1997Ultra-Fine Fabrication Technology, Ohm-sha (Japanese, Chapter author)
(3) 2000Sub-Half-Micron Lithography for ULSIs, Cambridge University Press (Chapter author)
(4) 2003Nanoelectronics and Information Technology, Wiley-VCH Gmbh & Co. KGaA (Chapter author)
(5) 2003Introduction to Semiconductor Lithography, Kogyo Chosakai (Japanese, Principal author)
(6) 2010 Revised Edition of Nanoelectronics and Information Technology, Wiley-VCH Gmbh & Co. KGaA (Chapter author)
(7) 2011Revised edition of Introduction to Semiconductor Lithography, Gijyutu Hyoronsya (Japanese, Principal author)
Symposium & Workshop Committee Activities
(1) 1999-2001Steering Committee co-Chairperson, EUVL Workshop
(2) 2002-2006Steering Committee co-Chairperson, EUVL Symposium
(3) 1999-2003Lithography Research Committee Chairperson, Si Technology Division, Japan Society of Applied Physics
(4) 1995-2003Program Committee Member, SEMICON Japan Technology Symposium
(5) 2004-2005 Program Committee Chairman, SEMICON Japan Technology Symposium
(6) 1990-1996Program Committee Member, International Conference on MicroProcess and Nanotechnology
(7) 1997-1998Program Committee Vice-Chairperson, International Conference on MicroProcess and Nanotechnology
(8) 1999-2000Program Committee Chairperson, International Conference on MicroProcess and Nanotechnology.
(9) 2002 Executive Committee Chairperson, International Conference on MicroProcess and Nanotechnology
(10) 1995-2006Program Committee Section Heads, International Symposium on Electron Ion and Photon Beams
(11) 2003-2006Steering Committee Member, International Conference on MicroProcess and Nanotechnology
(12) 2000-2005Executive Committee Member of NGL Research Committee of Japan Applied Physics Society
(13) Since 2006Vice Executive Committee Chairperson of NGL Research Committee of Japan Applied Physics Society
(14) 2000-2004Section Head of Lithography Research Society of Si Technology Sub-Committee of Japan Applied Physics Society