Repair of thin film wiring with laser-assisted processes

The ability to repair defective circuit elements on the high end packaging components being built by IBM for the System/390 is important in meeting yield and reliability targets. A number of laser-based technologies have been developed at IBM, establishing the capability to modify fine line circuit patterns on a range of packaging materials. The ability to control the laser/material interaction with the ability to successfully modify the circuit without adversely affecting the integrity of the dielectric is discussed. Removal of unwanted conductors is done with a computer-controlled, excimer-laser micromachining system operating at 308 nm. New conductor segments are created through the laser chemical vapor deposition of gold from the pyrolytic decomposition of dimethyl-Au-trifluoroacetylacetonate. The applications of these techniques to IBM´s thin film packaging are described, with specific focus on the two technologies introduced for the manufacture of high end, thin film packaging products