Source-mask optimization (SMO) in optical lithography has in recent years been the subject of increased
exploration as an enabler of 22/20nm and beyond technology nodes [1-6]. It has been shown that intensive
optimization of the fundamental degrees of freedom in the optical system allows for the creation of non-intuitive
solutions in both the source and mask, which yields improved lithographic performance. This paper
will demonstrate the value of SMO software in resolution enhancement techniques (RETs). Major benefits
of SMO include improved through-pitch performance, the possibility of avoiding double exposure, and
superior performance on two dimensional (2D) features. The benefits from only optimized source, only
optimized mask, and both source and mask optimized together will be demonstrated. Furthermore, we
leverage the benefits from intensively optimized masks to solve large array problems in memory use models
(MUMs). Mask synthesis and data prep flows were developed to incorporate the usage of SMO, including
both RETs and MUMs, in several critical layers during 22/20nm technology node development.
Experimental assessment will be presented to demonstrate the benefits achieved by using SMO during
22/20nm node development.
© (2011) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Kehan Tian ; Moutaz Fakhry ; Aasutosh Dave ; Alexander Tritchkov ; Jaione Tirapu-Azpiroz, et al.
Applicability of global source mask optimization to 22/20nm node and beyond
", Proc. SPIE 7973, Optical Microlithography XXIV, 79730C (March 22, 2011); doi:10.1117/12.879703; http://dx.doi.org/10.1117/12.879703