Photocurable formulation containing a partially polymerized divinylsiloxane linked bisbenzocyclobutene resin

Claim 1

A photocurable formulation containing at least one photosensitive agent in an amount sufficient to convert the mixture to an organic-insoluble solid upon exposing the mixture to photon radiation, and a DVS resin: (1) having a weight average molecular weight of greater than 90,000 g/mole as determined by size exclusion chromatography using narrow molecular weight range linear atactic polystyrene polymers as standards; (2) being soluble in mesitylene; and (3) being not polymerized beyond its gel point; (4) formed by a process consisting essentially of heating DVS monomer in a solvent at an initial concentration of DVS monomer in the solvent of from about 12 to about 32 weight percent such that the DVS resin: (a) when applied and polymerized in a ten micron thick layer on a solid substrate does not craze; and (b) when formulated by adding three weight percent 2,6-bis(4-azidobenzylidene)-4-methylcyclohexanone, spun coated onto a substrate, exposed to a photon source to cure at least a portion of the resin formulation beyond its gel point, any unexposed portions of the formulation are removed with a solvent and the photocured resin is finally cured with heat, one obtains a film retention of at least 75 percent.