For reference metrology, critical dimension atomic force microscopes (CD-AFMs) remain well utilized, despite the demand for ever smaller, stiffer, and more robust tips. Furthermore, within the past decade, a new form of tilt AFM, with imaging capabilities similar to CD-AFM, has been introduced and is gaining acceptance in manufacturing support.8,9 An alternative implementation of CD-AFM based on the vector approach probing method has also been developed to enhance measuring flexibility as well as to reduce tip wear.10 Finally, the past decade has also witnessed the dramatic rise of interest in critical dimension small angle x-ray scattering (CDSAXS) as a potential reference metrology.11,12