Non-Contact, Sub-Surface Detection of Alloy Segregation in Back-End of Line C…

Abstract—Alloy seedlayers for copper back-end of line interconnects have become common at technology groundrules of 45 nm and below, due to reliability requirements. The key requirement of the minority alloy component (e.g., Al or manganese, also referred to as the “dopant”) is that it segregates to the copper (Cu)/dielectric cap layer interface in order to promote adhesion between the C…