THERMAL-DESORPTION STUDIES OF PHOSPHORUS-DOPED SPIN-ON-GLASS FILMS

Thermal desorption spectroscopy was used to study an outgassing from silanol-based spin-on-glass films with phosphorus doping, cured at a temperature range between 200 and 400-degrees-C. Primary desorption products were found to be water and ethylene. Thermal desorption studies using a ramped heating revealed distinct desorption states for water and ethylene evolution between 60 and 600-degrees-C. Water desorbed from the films around 100-degrees-C via the decomposition of P-OH bonds. Simultaneous desorption of water and ethylene occurred at 280 and 430-degrees-C. The desorption at lower temperature originated from residual P-O-C2H5 bonds and the desorption at higher temperature from residual Si-O-C2H5 bonds in the films. Residual Si-OH bonds also provided water desorption around 280-degrees-C. It was confirmed that increasing the curing temperature effectively reduces the sources of outgassing. The residual ethyl components were found to be completely removed by high temperature annealing at 400-degrees-C.