Structure-property relationships of hydrido organo siloxane polymer (HOSP)

The structure and properties of Hydrido Organo Siloxane Polymer (HOSP) as a function of cure conditions have been analyzed. Fourier transform infrared spectroscopy, dielectric constant, and mechanical properties all indicated a dependence on the bake sequence of HOSP. FT-IR analysis indicated that the ratio of Si-O bonds in a caged (or ordered) configuration to Si-O bonds in a non-caged (or disordered) configuration changed as a function of both pre-cure hot plate bake conditions and cure temperature. The dielectric constant was lower for samples that received a high temperature hot plate bake (400°C) prior to the furnace cure independent of the furnace cure temperature, compared with samples that did not undergo the high temperature hot plate bake. In addition, adhesion was significantly improved with an increase in the cure temperature from 400°C to 430°C. These results indicate that both pre-cure hot plate bake conditions, and cure temperature affect the structure and therefore the properties of HOSP. Optimum properties are achieved when both the 400°C hot plate bake and a 430°C furnace cure are employed.