Substrate Heating Effects in Excimer Laser Planarization of Aluminum

Abstract

ABSTRACTSubstantial improvements in excimer laser planarization processes are observed with substrate heating. Cavities, associated with filling of high aspect ratio vias at low substrate temperature, can be eliminated by substrate heating. Damage associated with pulse overlap regions can be temperature sensitive, and is reduced as substrate temperatures areincreased. While required fluences for planarization and sample damage both decrease as the sample temperature increases, the relative insensitivity of the damage threshold generally results in larger process windows at higher temperatures. We also report model calculations of the effect of substrate heating on sample temperature distributions and the durations of the laser driven melts.