Advanced alignment optical system for DUV scanner

Tadashi Nagayama; Masahiko Yasuda; Yuho Kanaya; Takahiro Masada; Ayako Sugaya

doi:10.1117/12.535083

24 May 2004 Advanced alignment optical system for DUV scanner

Tadashi Nagayama, Masahiko Yasuda, Yuho Kanaya, Takahiro Masada, Ayako Sugaya

Proceedings Volume 5375, Metrology, Inspection, and Process Control for Microlithography XVIII; (2004) https://doi.org/10.1117/12.535083
Event: Microlithography 2004, 2004, Santa Clara, California, United States

Abstract

Advanced scanners need an extremely high accuracy wafer alignment system, and nowadays it is also necessary that the alignment marks occupy a smaller area in order to expand the available area for IC patterns. Therefore, narrower lines with a smaller pitch must form the alignment marks. In this paper, a higher Numerical Aperture (NA) and lower aberration alignment optical system are studied for these requirements. At first the small alignment marks are shown, and suitable NA in the optical system is then discussed. As a result, the necessity for higher NA is shown. As for low aberration, the necessary specification of wavefront aberration is discussed. Assuming it is possible to suitably select the NA and the illumination NA in the optical system, the results of simulation -- that simulate image signals and perform image processing -- are reported. These results show the optical system that has aberration causes position shift, so that the specification of wavefront aberration is estimated in order that the position shifts may be sufficiently small. To make sure that with such a strict specification the system will be possible, a trial optical system has been made. Finally the techniques of manufacturing and the results of evaluation are reported.

Citation Download Citation

Tadashi Nagayama, Masahiko Yasuda, Yuho Kanaya, Takahiro Masada, and Ayako Sugaya "Advanced alignment optical system for DUV scanner", Proc. SPIE 5375, Metrology, Inspection, and Process Control for Microlithography XVIII, (24 May 2004); https://doi.org/10.1117/12.535083

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available