9410224 Lumpp Economical manufacturing of high density microelectronic circuits depends on two critical factors: fabrication of fine pitch electrical interconnections and cost reduction by integration of processing steps. Both of these issues are addressed by using ultraviolet light to define circuit patterns. The new procedures utilize ultraviolet excimer lasers to locally decompose AIN and A12O3 surfaces to pattern high resolution metal lines for additive deposition of films without photolithography processing. Laser assisted chemical vapor deposition (CVD) from dimethylaluminum hydride produces a patterned seed layer by direct writing with the laser beam. Thin films are grown by selective area thermal CVD on the decomposed and seeded regions. In practice, adhesion of thick films on AIN has been poor due to nitrogen bubbles formed when the glass phase in the ink oxidizes the substrate. Thick film density is improved by screen printing onto decomposed regions so that the metallized surface is oxidized without blistering the film. Metallized vias are fabricated by laser ablation of the substrate and a detachable metal backing. Electrical properties of films, vias and laser modified surfaces are correlated with chemical analysis results and evaluation of microstructural development. ***
