EUV Photoresist Reference Metrology Using TEM Tomography

摘要

Process monitoring of extreme ultraviolet (EUV) photoresist requires critical dimension analysis and careful control of extracted parameters like line edge roughness (LER) and line width roughness (LWR). Automated SEM metrology typically provides estimates for these parameters, including critical dimensions and "shape, " but at the cost of SEM exposure modifying the shape and size of the material systems. A method for acquiring and analyzing dense line structures using TEM tomography is proposed. Automation of the process from in-fab photoresist encapsulation through dual-beam lamella preparation to tomography acquisition is described, followed by a discussion of novel methods for volumetric reconstruction with metrology. Measurement capabilities are compared to CDSEM and AFM. Novel three-dimensional constructs illustrating process and property relationships in the lithography module are provided.