We experimentally demonstrate that the three-dimensional (3-D) shape variations of nanometer-scale objects can be resolved and measured with sub-nanometer scale sensitivity using conventional optical microscopes by analyzing 3-D optical data using the through-focus scanning optical microscopy (TSOM) method. These initial results show that TSOM-determined cross-sectional (3-D) shape differences of 30 nm to 40 nm wide lines agree well with critical-dimension atomic force microscope measurements. The TSOM method showed a linewidth uncertainty of 1.22 nm (k=2). Complex optical simulations are not needed for analysis using the TSOM method, making the process simple, economical, fast and ideally suited for high volume nanomanufacturing process monitoring.
Citation: Applied Physics Letters
Pub Type: Journals
TSOM, nanometrology, three-dimensional metrology, through-focus scanning, nanomanufacturing, nanotechnology, MEMS, NEMS, defect analysis, process control