COPPER FILLED OPENING WITH A CAP LAYER

摘要

The invention concerns openings in substrates filled with a copper deposit. Thermal annealing processes lead to an irreversible expansion of said copper deposit and hence to the formation of voids in the copper deposit and cracks between the surface of the substrate and active or passive overlying structures. The present invention provides cap layers which suppress the irreversible expansion of copper during or after thermal annealing.