Description

Optical lithography is being pushed into a regime of extreme-numerical aperture (extreme-NA). The implications of the nonscalar effects of high-NA lithography (above 0.50) have been discussed now for many years1. This paper considers the consequences of imaging at numerical apertures above 0.70 with the oblique imaging angles required for low k1 lithography. A new scaling factor, kNA, is introduced to capture the impact of low k1 imaging combined with extreme- NA optics. Extreme-imaging is defined as k1 and kNA values approach 0.25. Polarization effects combined with resist requirements for extreme-NA are addressed, especially as they relate to 157nm lithography. As these technologies are pursued, careful consideration of optical and resist parameters is needed. Conventional targets for resist index, absorption, diffusion, and reflectivity based on normal incidence imaging may not lead to optimum performance without these considerations. Additionally, methods of local and semi-local mask polarization are discussed using concepts of wire-grid polarizer arrays. Back-side and image-side polarization OPC methods are introduced.

Date of creation, presentation, or exhibit

3-5-2002

Comments

Proceedings of the SPIE Conference on Optical Microlithography XV, vol. 4691, Santa Clara, California, March 5, 2002 Note: imported from RIT’s Digital Media Library running on DSpace to RIT Scholar Works in February 2014.

Document Type

Conference Proceeding

Department, Program, or Center

Microelectronic Engineering (KGCOE)

Campus

RIT – Main Campus

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