The effects of La2O3 doping on the photosensitivity, crystallization behavior and dielectric properties of Li2O-Al2O3-SiO2 photostructurable glass

Photostructurable Li2O-Al2O3-SiO2 glass is a promising material to fabricate complex three-dimensional structure with a high aspect ratio. However, its high dielectric loss at high frequencies has restrained its application in the field of integrated circuits packaging. In this research, La2O3, which has a large ionic radius, as well as strong polarization and bonding strength, was used to obstruct mobile ion migration to reduce the dielectric loss. The results indicated that moderate doping with La2O3 could effectively reduce the dielectric loss. When the dopant amount was 3%, the dielectric loss was successfully reduced to a minimum of 4 × 10−3 with a dielectric constant of 6.6 at 1 GHz, and this sample also possessed the optimal dielectric-temperature stability. Additionally, the effects of doping on the photosensitivity and crystallization behavior were also analysed. The results suggested that La2O3 doping did not affect the photosensitivity and selective crystallization characteristics. However, La2O3 restrained the precipitation of silicate from the [SiO4] tetrahedron, resulting in a decrease of nucleation rate and a delay of crystallization.