EUV stochastic effects are generally studied [1-7] from the point of view of Line-Edge-Roughness (LER), Line-Width-Roughness (LWR), Local CDU (LCDU), i.e. from the point of view of the CD-Variability of the printed patterns. In this paper we will look at what happens when this variability gets worse and turns into (random) locally failing patterns, such as missing contacts or locally closed trenches. In doing so, these failures contribute to setting the effective printability limit for the experimental conditions and the type of structures that are being considered. We will first discuss the way in which we have tried to quantify the amount of locally failing structures, i.e. the metrics we have adopted to describe them. Next we describe how the amount of locally failing structures depends on some pattern-related and experimental condition-related parameters. From this we concluded that – as in the case of local variability – the amount of local failure depends on the exposure dose used (the well-known photon shot noise effects) as well as on mechanisms that originate in the resist or the process. Although we have not been able to identify what this resist- or materials component is exactly, we do have some indications that point to the development step, but we will also discuss other potential contributors.

Date Published: 17 April 2014
PDF: 15 pages
Proc. SPIE 9048, Extreme Ultraviolet (EUV) Lithography V, 904809 (17 April 2014); doi: 10.1117/12.2047827

Published in SPIE Proceedings Vol. 9048:
Extreme Ultraviolet (EUV) Lithography V
Obert R. Wood II; Eric M. Panning, Editor(s)