Cost-effective air-gap interconnects by all-in-one post-removing process

Low process cost air-gap structure for multilevel interconnect system is proposed by all-in-one post-removing process. Problems regarding the air-gap process were studied and solutions for moisture uptake and for metal wiring oxidation were developed. The proposed air-gap process is compatible with the conventional BEOL process. Furthermore, this process can build the air-gap structure with least additional process steps, and it tolerates misalignment.