Low κ, Low Loss Alumina-Glass Composite with Low CTE for LTCC Microelectronic Applications

Abstract

Alumina based low κ LTCC composite has been prepared with the use of AGC commercial glass (DL828). The 30 wt% Al2O3–70 wt% AGC glass composite was sintered at 875 °C (2 h). X-ray diffraction study indicated the presence of BaSi2O5, BaAl2Si2O8 and Ba2Si3O8 secondary phases in addition to Al2O3 in the composite. The bulk ceramic sintered at 875 °C has κ of 4.80 and tan δ of 0.007 at 1 MHz. The composite shows good microwave dielectric properties: κ of 4.52, tan δ of 0.004 and τκ close to zero. The composite has a low CTE of 4.38 ppm/°C which is close to that of silicon used in microelectronic industry and thermal conductivity of 1.41 W m−1 K−1 at room temperature. The results indicate that the Al2O3 - AGC glass composite has good dielectric, thermal properties and is chemically compatible with Ag electrode indicating it as a promising candidate for low κ LTCC substrate applications.