Proc. SPIE. 9256, Photomask and Next-Generation Lithography Mask Technology XXI
KEYWORDS: Metrology, Sensors, Atomic force microscopy, Scanning electron microscopy, Transmission electron microscopy, Time metrology, 3D metrology, Photomasks, Algorithm development, 3D image processing
In next generation lithography (NGL) for the 1x nm node and beyond, the three dimensional (3D) shape measurements such as side wall angle (SWA) and height of feature on photomask become more critical for the process control. Until today, AFM (Atomic Force Microscope), X-SEM (cross-section Scanning Electron Microscope) and TEM (Transmission Electron Microscope) tools are normally used for 3D measurements, however, these techniques require time-consuming preparation and observation. And both X-SEM and TEM are destructive measurement techniques. This paper presents a technology for quick and non-destructive 3D shape analysis using multi-channel detector MVM-SEM (Multi Vision Metrology SEM), and also reports its accuracy and precision.
A new SEM technology is becoming available that allows image-based 3D profile metrology of nanoscale features. Using patented multi-channel detector technology, this system can acquire information of surface concave and convex features, and sidewall angle (SWA) and height of profiles, quickly and non-destructively for nanoscale structures such as fin field-effect transistors (FinFETs), using electron beam technology with its well-known long probe lifetime, stability and small probe size. Here we evaluate this new technology and demonstrate its applicability to contemporary advanced structures such as FinFETs, including not only CD, but also profile, SWA, top corner rounding (TCR) and bottom corner rounding (BCR).