Laser direct writing of aluminum multilevel interconnects for VLSI applications

Laser direct writing of high-purity aluminum interconnects from trimethylamine aluminum hydride was demonstrated. A focused Ar⁺ laser at 514.5 nm was used to pyrolytic chemical vapor deposition of Al lines on CMOS VLSI test die. The laser-written interconnects with a width varied between 2 and 15 ¿m with typical thickness from 0.1 to 3.0 ¿m were deposited at writing speed up to 1200 ¿m/s. The new in situ laser-writing technique has been developed for applying two-level metal interconnects and polyimide as an interlevel dielectric by combining visible Ar⁺ laser CVD and UV N2 laser ablation in a single process step.