Fabrication, characterization and sintering of glass-ceramics for low-temperature co-fired ceramic substrates

Abstract

Cordierite-based glass-ceramics with non-stoichiometric composition doped with rare earth oxide (CeO₂) and heavy metal oxide (Bi₂O₃) respectively were fabricated from glass powders. After sintering and crystallization heat treatment, various physical properties, including compact density and apparent porosity, were examined to evaluate the sintering behavior of cordierite-based glass-ceramics. Results showed both that the additives heavy metal oxide and rare earth oxide promoted the sintering and lowered the phase temperature from μ- to α-cordierite as well as affecting the dielectric properties of sintered glass-ceramics. The complete-densification temperature for samples was as low as 900 °C. This material has a low dielectric constant (≈5.3), a low dielectric loss (≤0.2%) and a low thermal expansion coefficient (2.8–3.52×10⁻⁶ K⁻¹), and can be co-fired with high conductivity metals such as Au, Ag, Cu, Ag/Pd paste at low temperature (below 950 °C), which makes it a promising material for low-temperature co-fired ceramic substrates.