The effects of Y2O3-CaF2 on the properties of AlN packaging substrate

Aluminum nitride with high thermal conductivity is an important packaging substrate material. The effects of Y
₂
O
₃
and CaF
₂
on sintering properties, phase composition and microstructure for AlN ceramics were studied. The results show that the addition of Y
₂
O
₃
and CaF
₂
improves the microstructure and density of ceramics. The bulk density and thermal conductivity of AlN ceramics with 1.8% Y
₂
O
₃
and 1.2% CaF
₂
are 3.286 g/cm
³
and 192 W/ (m·K) respectively. The microstructure analysis shows that the grain size of AlN is more homogeneous and less grain boundary phase which is distributed at the grain corner junction and independent of each other.