Monitoring Cu via structures and surrounding dielectric stack after CMP process

This study focuses on processed wafers undergoing the chemical mechanical planarization (CMP) process, with a particular emphasis on monitoring the dielectric stack thickness between Cu VIA structures, patterned in approximately a 45 μm raster. Spectroscopic ellipsometry was applied to determine the one-dimensional stack multilayer thickness, while imaging spectroscopic reflectometry was used to reveal the lateral thickness profile.