Stochastic noise has strong impact on local variability such as LWR (Line Width Roughness), LCDU (Local Critical Dimension Uniformity) and LPE (Local Placement Error), and it is basically originated from the particle nature of photon. Statistical uncertainties of particles, same as the stochastic noises, can be analytically calculated by considering aerial image as a probability density function of photons. Contact-hole is the best pattern for counting its photon, so LCDU of contact-hole array is estimated and compared with experimental results. Among several possible statistical events from mask to resist pattern, three independent events of aerial image formation, photon absorption in resist, and chemical reaction including acid generation are considered to predict stochastic noise for both EUV (Extreme Ultra Violet) and ArF immersion lithography.

Date Published: 7 April 2015
PDF: 11 pages
Proc. SPIE 9422, Extreme Ultraviolet (EUV) Lithography VI, 94220M (7 April 2015); doi: 10.1117/12.2087559

Published in SPIE Proceedings Vol. 9422:
Extreme Ultraviolet (EUV) Lithography VI
Obert R. Wood II; Eric M. Panning, Editor(s)