The effect of boron anomaly on the dielectric properties and thermal expansion of barium borosilicate glasses for 3D packaging systems

Barium borosilicate (BBS) glass is a potential three-dimensional system packaging and sensor cover material. In this study, we prepared glass samples with different SiO2/B2O3 ratios based on the revised model of Dell and Bray and discussed the effect of boron anomaly on dielectric and thermal properties through Raman spectroscopy. The results indicate that the [BO4] tetrahedrons are beneficial in reducing the dielectric constant and dielectric loss to a certain extent, while the improvement in the coefficient of thermal expansion (CTE) is attributed to the depolymerization of the glass network by the [BO3] triangles. After the disappearance of the boron anomaly, a certain amount of dielectric performance is sacrificed in exchange for an increase in the CTE. When the substitution rate of B2O3 for SiO2 reaches 15.12 mol%, the CTE of the sample increases to 8.43 x 10(-6)/degrees C, in addition, the dielectric constant and dielectric loss decrease to 4.90 and 0.0071 (@1 GHz), respectively. In summary, this work provides a suitable method for preparing glass with a high coefficient of expansion and low dielectric loss to address the thermal mismatch effect of different materials in electronic packaging systems.