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Metal (Au, Cu, and Al-1% Cu) layers sputter deposited over vias and contact holes of varying diameter and aspect ratio are melted and planarized by irradiation with either a 600 ns pulse duration flashlamp-pumped dye laser or a 35 ns pulse duration excimer laser. High aspect ratio (>=1) vias and contact holes yield metal profiles that suffer from void formation during the laser-induced flow. This void formation is explained by considering surface tension forces that, in high aspect ratio cases, act to close off the top of a hole without filling it. [ABSTRACT FROM AUTHOR]

The differences between excimer (≊30 ns pulse duration) and flashlamp-pumped dye (≊500 ns pulse duration) laser planarization are examined for 1.5–2 μm thick gold films over SiO2 layers. Test structures containing bar patterns (square waves) of 5000 Å peak-to-trough amplitude with spatial periods ranging from 10 to 100 μm were prepared and laser irradiated. A linear model is presented which described the time evolution of the film’s surface topography when melted with a dye laser pulse. Excimer laser planarization is found to be susceptible to evaporative recoil effects which may cause undesired pattern amplification. [ABSTRACT FROM AUTHOR]