Atomic force microscope caliper for critical dimension measurements of micro and nanostructures through sidewall scanning

摘要

A novel atomic force microscope (AFM) dual probe caliper for critical dimension (CD) metrology has been developed. The caliper is equipped with two facing tilted optical fiber probes (OH's) wherein each can be used independently to scan either sidewall of micro and nanostructures. The OFP tip with length up to 500 mu m (aspect ratio 10:1, apex diameter >= 10 nm) has unique features of scanning deep trenches and imaging sidewalls of relatively high steps with exclusive profiling possibilities. The caliper arms-OFPs can be accurately aligned with a well calibrated opening distance. The line width, line edge roughness, line width roughness, groove width and CD angles can be measured through serial scan of adjacent or opposite sidewalls with each probe. Capabilities of the presented AFM caliper have been validated through experimental CD measurement results of comb microstructures and AFM calibration grating TGZ3. (C) 2015 Elsevier B.V. All rights reserved.