Effects of debinding process on properties of sintered AlN substrate

We fabricated the AlN substrate using tape casting method and investigated the effect of carbon content on sinterability and thermal conductivity. The carbon residue content was measured after the debinding of the AlN green sheet containing 1 wt% Ca–Al–Si–O glass (CAS glass) in the range of 300–1000°C in atmospheres of air, N₂, vacuum, and wet N₂. The carbon residue content was 0.21 wt% after debinding in the wet N₂ atmosphere at 800°C, 0.59 wt% after debinding at 1000°C in the N₂ atmosphere, and 1.1 wt% after debinding in the N₂ atmosphere at 700°C. The debinded specimen was sintered at 1850°C for 3 h in the N₂ atmosphere. As a result, when the residual carbon content was 0.2 wt%, the bulk density was found to be highest with 3.22 g/cm³, and the thermal conductivity was 93 W/m∙K. When the residual carbon content was 0.59 wt%, the bulk density was almost the same at 3.21 g/cm³, and the thermal conductivity was significantly increased to 161 W/m∙K. When the residual carbon content was 1.1 wt%, the bulk density was 2.71 g/cm³, and the thermal conductivity was 60 W/m∙K, degrading the sintered properties.