Process monitoring and surface characterization with in-line XPS metrology

摘要

An X-ray photoelectron spectrometer (XPS) is used at 65nm and 45nm nodes to monitor nitrogen dose and the SiON thickness of ultra thin nitrided gate oxides as well as the thickness of amorphous silicon on top of an amorphous carbon stack. XPS is also used as a process characterization technique in the fabrication line and allows for nondestructive chemical composition and bonding state analyses along with thickness measurements. Two examples of surface characterization are the influence of a dry cleaning plasma step on a silicon surface for the source/drain implantation process, and fluorine contamination of a TiN hard mask for interconnect applications.