Fabrication of high-quality green tape with aqueous nanoalumina slurry for 99.6% purity alumina ceramic substrate
摘要
High-purity alumina ceramic substrates are widely used in integrated circuit packaging owing to their excellent mechanical strength and thermal conductivity. However, traditional organic tape casting processes rely on toxic solvents, posing environmental and operational risks. Herein, an emulsion composite binder is designed using deionized water as solvent to replace the single binder, and pretreated alumina powder is used to prepare high-purity alumina ceramic substrates by aqueous tape casting. The effects of aqueous slurry formulation, sintering temperature, and powder particle size on the microstructure and properties of the ceramic substrates are investigated. Experimental results show that high-quality ceramic green tape with a density of 2.249 g/cm3 and a tensile strength of 0.965 MPa is obtained when the aqueous slurry exhibits pH 11–12, dispersant content of 2 wt%, solid content of 54 wt%, R value (the plasticizer-to-binder ratio) of 0.25, and scraper height of 800 μm. The ceramic substrate prepared using 100 nm pretreated powder and sintered at 1550 °C achieved a density of 3.91 g/cm3 with an average surface roughness of only 37.6 nm. In particular, the 99.6% alumina ceramic substrate exhibits excellent physical and mechanical properties, with thermal conductivity and hardness of 32.74 W/(m K) and 2365.4 HV, respectively, providing a sustainable strategy for the preparation of high-quality ceramic substrates in advanced electronic applications.
Graphical abstract