Preparation of Slurry for Tape Casting of AlN Ceramic Substrates

AlN ceramics are employed in a multitude of applications including large-scale integrated circuit (LIC) packaging substrates, electrostatic chucks, and transparent ceramics due to their excellent thermal conductivity, insulation and dielectric properties, robust corrosion resistance, and thermal expansion coefficient nearly identical to that of silicon. Tape casting is the optimal methodology for the fabrication of large-area, thin, and flat ceramics and components. However, the well-dispersed slurry with high solid loading is required to obtained the ceramic substrates with excellent properties by tape casting. Therefore, in this study, the effects of dispersant content, first ball milling time, binder content, and R value (plasticizer/binder) on the rheological properties of aluminum nitride slurry and casted sheet qualities were investigated. The results indicated that the optimal dispersant formulation was 1.1 wt%, the binder formulation was 2 wt%, the R value was 1.5, and the solid content was 60 wt%. The utilization of the aforementioned organic system enabled the preparation of AlN sheet exhibiting favorable morphology, high solid content, and flexibility.