Low-temperature cofirable ceramics Mg 2 SiO 4 -CaTiO 3 : Composition design, sintering behavior, and tape-casting process development
Year: 2026
Type: conference-paper
Abstract: For applications in low-temperature co-fired ceramics (LTCC), a low-dielectric-constant ceramic system based on Mg 2 SiO 4 was investigated. This study addressed three challenges: phase stabilization of Mg 2 SiO 4 , adjustment of dielectric properties by adding CaTiO 3 , and reduction of the sintering temperature to a range relevant to silver metallization and multilayer processing using tape casting. Mg 2 SiO 4 was selected as the matrix material due to its inherent low dielectric constant and low microwave loss. The Mg/Si molar ratio was adjusted to 2.05 to suppress parasitic MgSiO 3 formation, while CaTiO 3 was introduced to regulate dielectric properties and temperature stability. An optimum composition window of 9–10 wt% CaTiO 3 was obtained. The ceramic containing 10 wt% CaTiO 3 exhibited ε r = 9.14, Q × f = 68,542 GHz, and τ f = +2.56 ppm/°C. To reduce the firing temperature, RO–B 2 O 3 –SiO 2 glasses were used as sintering aids. ZnO–B 2 O 3 –SiO 2 glass enabled dense sintering at approximately 1000 °C while retaining the Mg 2 SiO 4 /CaTiO 3 primary phases. Tape casting was achieved using powders with D50 ≤ 2 μm and D90 ≤ 10 μm and a slurry viscosity of 1000–3000 mPa·s. The fired substrate showed a flexural strength of 190 MPa, coefficient of thermal expansion of 7.8 ppm/°C, thermal conductivity of 4.4 W/(m·K), and X–Y shrinkage of 19.5% ± 0.2%. These results indicate that Mg 2 SiO 4 –CaTiO 3 ceramics are promising low-loss LTCC substrate materials for multilayer microwave packaging.
Authors: Hao Bai, Shuhao Cai, Jiali Wang, Zhenguo Liu
Institution: Northwestern Polytechnical University
Subfield: Electrical and Electronic Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: diamond
OpenAlex ID: W7205011376