Published online by Cambridge University Press: 28 February 2011
The deep ultraviolet (250 nm) photopatterning of spin-on films of polymeric Au mercaptide results in formation of adherent Au patterns. Fxcimer laser projection patterning and standard contact printing techniques give excellent pattern resolution on the micron scale. Laser direct write produces lines at very fast writing speeds. Exposed areas are less soluble than unexposed areas, i.e. the film behaves as a negative photoresist. Bakeout of developed patterns at 250°C yields good purity Au micropatterns up to 500 Å thick. Mechanistic information about pattern formation is gained from uv-visible, infrared, and mass spectrometric monitoring of the photolysis process, and from Auger analysis of films. Adherent patterns are apparently formed by photochemical cleavage of Au-S bonds followed by evaporation of a small amount of free mercaptide. The loss of ligand in the exposed areas renders them less soluble than unexposed film. Thermal decomposition of both photolyzed and unphotolyzed films has the same result of volatilizing all film material except Au.