Stress migration in a copper - Aluminum hybrid technology

Stress migration (SM) time, temperature and process dependencies are investigated using a highly sensitive tungsten to copper interface combined with “plate-nose” and “mesh-nose” structures to accelerate the SM mechanism. Voids formed below the W via on the nose, and the resistance increases caused by these voids peaked at temperatures of 300-325°C. The effects of several copper line and tungsten via process steps are discussed. Process steps which modulated the Cu surface and Cu to via bottom interface had the largest effects.