Effect of the electrosteric stabilization mechanism, sintering additives, and sintering process on the properties of 3D-printed alumina ceramics

With the development of 5G and high-power electronic devices, the demand for high-performance alumina ceramic packaging substrates has grown significantly. However, traditional manufacturing processes face issues such as high energy consumption and limited shape complexity, while additive manufacturing technologies (DLP 3D printing) encounter challenges like weak interlayer bonding and insufficient mechanical properties. This study explores the development of low-viscosity alumina slurries by optimizing the ratio of photosensitive resin to dispersants (BYK-110 and KH-570). Through the synergistic effects of sintering additives (ZrO2, SiO2, Y2O3) and sintering processes, it systematically investigates the preparation and performance regulation mechanisms of high solid-loading alumina ceramics. The results demonstrate that, at a photosensitive resin: BYK-110:KH-570 ratio of 6:1:7, the slurry achieves the lowest viscosity (0.7377 Pa·s), enabling successful fabrication of alumina ceramics with a maximum solid loading of 88 wt%. Samples produced with 2 wt% Y2O3 as a sintering additive exhibit the highest flexural strength across all sintering processes. When both the maximum sintering and re-sintering temperatures reach 1650°C, the flexural strength peaks at 138.17 ± 17.89 MPa. The optimal overall performance of alumina ceramics occurs at a maximum sintering temperature of 1450°C. Silica as a sintering additive under this process provides the lowest shrinkage rates: X-direction: 3.84 ± 0.25%, Y-direction: 4.79 ± 1.33%, Z-direction: 4.17 ± 0.87%, along with the highest open porosity (21.95 ± 0.3%), bulk density (3.52 ± 0.07 g/cm3), and sufficient flexural strength (91.50 ± 7.94 MPa). This study provides theoretical support for the compositional design and process optimization of high solid-loading alumina slurries for the additive manufacturing of electronic packaging.