To first order, the use of AFM as a reference tool potentially offers a large improvement over pre'ious techniques for matching and calibration of on-line CL)-SEMs. However, the utility of this approach depends on the validity of the assumption that AFM precision and accuracy are relatively constant with sample type. A fullfactorial design using analysis of variations (ANOVA) has been employed in order to gauge the precision of a non-contact mode CD AFM over multiple sample types and instrument conditions. 'The effects of material layer, pattern geometry, feature shape, and tip size on AFM precision viill he presented.
Herschel M. Marchman,
"AFM: a valid reference tool?", Proc. SPIE 3332, Metrology, Inspection, and Process Control for Microlithography XII, (8 June 1998); doi: 10.1117/12.308718; https://doi.org/10.1117/12.308718