What is prevalent CD-SEM's role in EUV era?

As industry prepares to introduce extreme ultraviolet (EUV) technology for the coming sub-10-nm lithography, this paper presents metrology approaches that utilize the prevalent Critical Dimension Scanning Electron Microscope (CD-SEM). Two technical approaches will be discussed. One is comprehensive solutions for new EUV characterized features, such as low resist-shrinkage electron beam optics and high efficiency metrology/inspection for EUV process monitoring. The other, like conventional minimization processes, is down-to-angstrom-order metrology methodologies required for stricter CD process control. This paper is the first to conceptualize specifications for a stringent and multi-index tool matching, namely "atomic matching," which is considered as a crucially important feature of any in-line metrology tools in the EUV era.