This paper discusses the nonhermetic performance of polymer thin film coatings derived from 1,3-bis(2-bicyclo[4.2.0]octa-1,3,5-trien-3-ylethenyl)-1,1,3,3-tetramethyl disiloxane (mixed isomers, CAS 117732-87-3), known also as divinyl siloxane bis-benzocyclobutene or DVS bis-BCB. The stability of the dielectric constant and the mechanical properties have been examined before and during high temperature exposures of the polymer films to air for extended periods of time at high and low humidity. Infrared absorbance spectra and dielectric constant measurements have been correlated.
Formulations of the DVS bis-BCB prepolymer with a polymeric oxidation inhibitor are predicted to yield polymer films which display less than a 10% change in the dielectric constant after 40 years in air at 85°C. These films have excellent potential for use as the dielectric coating layer in nonhermetic packaging applications for Multi Chip Module (MCM) circuits.