Laser direct writing of metal interconnects

Laser direct writing of metals offers the advantages of in-situ design and repair of IC´s with a process that can be controlled and altered from chip to chip to meet the designer´s needs. A summary of the laser direct writing techniques for metal deposition -- photolytic, pyrolytic, and photo-thermal is presented with an emphasis on the advantages of each technique based on recent results. In particular, we have sought to produce high-quality metal interconnects suitable for VLSI dimensions of 2-3um linewidths, yet with resistivities 3-5 times the bulk metal used. An important aspect of the study involved the penetrating of the native oxide layer that exists on evaporated Al metallizations in order to make low resistivity interconnect lines.