Method for reducing stress-induced voids for 0.25 micron and smaller semiconductor chip technology by annealing interconnect lines prior to ILD deposition and semiconductor chip made thereby

摘要

A method for making 0.25-micron semiconductor chips includes annealing the metal interconnect lines prior to depositing an inter-layer dielectric (ILD) between the lines. During annealing, an alloy of aluminum and titanium forms first, which subsequently volumetrically contracts, thereby forming a titanium aluminide compound, with the contraction being absorbed by the aluminum. Because the alloy is reacted to form the metal compound prior to ILD deposition, however, the aluminum is not constrained by the ILD when it attempts to absorb the contraction of the alloy. Consequently, the likelihood of undesirable void formation in the interconnect lines is reduced.