INFLUENCE OF THE PREPARING CONDITIONS ON THE PHYSICOCHEMICAL CHARACTERISTICS OF GLASSES FOR THICK-FILM HYBRID MICROELECTRONICS

Seven batches of a high-lead glass were used for the preparation of Ru O2-based thick film resistors. Investigation of their electrical prope rties showed a lack of reproducibility of results whose origin was rel ated to changes of the physicochemical properties of the glassy matrix . A systematic investigation of the glass batches, both in form of fri t powders and screen printed and fired layers, was carried out with se veral spectroscopies to detect changes in composition and structure. T he spectroscopic methods included x-ray Energy Dispersive Fluorescence (EDS), Scanning Electron Microscopy (SEM), Atomic Absorption (AA), di ffuse optical reflection of the powders and specular reflection of the layers, optical transmission, and other complementary methods. The di ssolution of Al, due to interaction between the glasses and the alumin a substrate, as well as the diffusivity and solubility of Ag due to in teraction with the Ag-bearing terminations were measured. The results demonstrated that, apart from small compositional differences, the var ious batches were characterized by differences in residual stresses, r edox reactions, and ''microstructure.'' The latter was responsible for very notable differences in the optical properties of the glasses, wh ich in turn are closely related with the difference in atomic solubili ty and diffusivity. Optical spectroscopies have been found to be a sui table means for testing reproducible preparation methods of glass frit s for thick-film hybrid microelectronics.