Corrosion of High Thermal Conductive AlN Ceramics in Aqueous Solutions

Abstract

Although there is a strong need to understand the chemical corrosion resistance of aluminum nitride (AlN) ceramics for their applications as structural parts in semiconductor processes, there is insufficient information on chemical corrosion. We examined two kinds of commercial AlN ceramics with high thermal conductivity (170 and 200 W m -1 K -1 ) in both acid and basic aqueous solutions, such as KOH, NaOH, HNO 3 and H 2 SO 4 , using different concentrations. Weight changes, phases present, and microstructures on the surfaces before and after testing were evaluated. Basic aqueous solutions corroded AlN ceramics in exactly the same way as acid aqueous solutions. Although secondary phases, such as yttrium aluminate, were mainly dissolved in acid aqueous solutions, AlN itself was corroded in basic aqueous solutions. Furthermore, we observed that the weight loss of AlN ceramics with higher thermal conductivity exceeded that of lower thermal conductivity. It seems that oxygen dissolved in AlN grain influences on corrosion of AlN ceramics.