Features of the Three-Dimensional Profile Control of the Elements and Structures of Nanoscale ICs: A Review

With the transition to the region of critical dimensions (CDs) less than 100 nm, the two-dimensional (planar) shapes of the structures of elements manufactured during the technological cycle change to three-dimensional complex shapes. These are various gate structures of MOS transistors, oxide and nitride masks for photolithography, fin gate transistors (FinFETs), gate-all-around transistors (GAА-ЕETs), etc. Process validation, in addition to the requirements for the CDs of elements in the plane, also includes requirements for the precision of measurements of the full profile. Despite the wide variety of methods currently developed for measuring linear dimensions and surface profiles, not all of them can be applied to control the three-dimensional profile of the manufactured structures. Based on the analysis of the published data, this study shows the features of currently widely used tecniques for measuring linear dimensions and topological elements, and it identifies the problems of using them for monitoring a three-dimensional profile. Promising measurement techniques currently being implemented in the production of ICs are considered.