Ultra-Low-TemperatureCofired Ceramic Substrates withLow Residual Carbon for Next-Generation Microwave Applications

摘要

High-temperature cofired ceramics and low-temperature cofired ceramics are important technologies in the fabrication of multilayer ceramic substrates for discrete devices, electronics packages, and telecommunications. However, there is a place and need for materials with lower fabrication temperatures to decrease the associated energy consumption. The present paper studies the feasibility of two ultra-low sintering temperature cofired ceramic materials, copper molybdate and copper molybdate–Ag2O, sinterable at 650 and 500 °C, respectively, for multilayer substrates using tape casting. The slurry composition developed uses environmentally friendly organics and a nontoxic binder and solvent. Additionally, the green cast tapes exhibit very low residual carbon (less than 5%) after sintering on analysis by X-ray photoelectron spectroscopy. The multilayer substrates show a permittivity value of about 8 with a low dielectric loss in the range of 10^–5 to 10^–4 in the frequency range of 2–10 GHz along with a low coefficient of thermal expansion in the range of 4–5 ppm/°C and good compatibility with an Al electrode. Thus, these proposed substrates have much promise, with good thermal,mechanical, and dielectric properties comparable to commercial substrateswhile also providing an energy and environment-friendly solution.