12 May 2004 The impact of mask topography on CD control
Author Affiliations +
Abstract
Past work on mask topography has documented the effects of the topography on the aerial image intensity and on the responses of CD through defocus and image placement. Device performance, however, is limited by the statistical CD variation in the poly lines that form the logic and memory gates. We have developed a tool that combines fast, rigorous EMF calculations with Monte Carlo simulation to investigate the impact of mask topography on CD control. We have applied it to study the effects of mask topography on through-pitch CD control in 6% EAPSM, AAPSM, and CPL reticles at 90-nm half-pitch design rules. The effects of the topography can be understood by examining the coefficients of the Fourier expansion of the near-field radiation pattern. The magnitude of the 3D effects is not correlated with the amount of mask topography but with the specific details of the Fourier coefficients that pass through the pupil. The topography mainly distributes the energy more evenly and introduces additional phase information. The best imaging results at tight pitch are obtained when the difference between the magnitudes of the two main Fourier coefficients that pass through the pupil is small and their phase difference is close to π. At larger pitches more diffracted orders will pass through the pupil, and the extra phase information from the additional orders will couple with aberrations in a reticle-dependent way and complicate overall RET choice.
© (2004) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Jonathan L. Cobb, Jonathan L. Cobb, Bernard J. Roman, Bernard J. Roman, Vladimir Ivin, Vladimir Ivin, M. Sarychev, M. Sarychev, } "The impact of mask topography on CD control", Proc. SPIE 5754, Optical Microlithography XVIII, (12 May 2004); doi: 10.1117/12.601175; https://doi.org/10.1117/12.601175
PROCEEDINGS
12 PAGES


SHARE
RELATED CONTENT

Effect of phase error on 180 nm and 250 nm...
Proceedings of SPIE (July 28 1997)
High-transmission PSM inspection sensitivity
Proceedings of SPIE (December 30 1999)
Limits of optical lithography
Proceedings of SPIE (July 05 2000)
Challenge for sub 100 nm DRAM gate printing using ArF...
Proceedings of SPIE (March 11 2002)
Defect printability in CPL mask technology
Proceedings of SPIE (May 28 2004)

Back to Top