Low resistance dual damascene process by new Al reflow using Nb liner

Abstract

Summary form only given. This paper describes excellent Al filling characteristics and low resistance dual damascene interconnects obtained with a new Al reflow process using Nb liner. This novel process can fill vias of AR4 and can achieve 40-50% drop in resistance compared with current RIE-Al lines and reflow-Al lines with Ti liner. These properties are attributed to a slower reaction rate between Nb and Al. Excellent via electrical properties have been verified across 200 mm wafers using this process. This new process is a leading candidate for sub-0.25-0.15 um Al metallization.