The present invention relates to a method of accessing and repairing electrical opens in conducting metal lines on a semiconductor chip or other substrate using laser plating techniques. What has been described is a maskless means of repairing discontinuities in a conductor disposed on the surface of a substrate wherein the surface is locally irradiated to form a reversible carbonaceous layer thereon. This reversible carbonaceous layer acts as a base for electrodeless deposition of a metal to form a bridge across the discontinuity by laser-enhanced exchange plating or other suitable methods. Further, a means of accessing and repairing a discontinuity buried by a cover layer of an insulating or passivating material is described, wherein access to the discontinuity is provided by ablating away the cover layer using a pulsed excimer laser at a first power level.