LOW-TEMPERATURE CO-FIRED MICROWAVE DIELECTRIC CERAMIC MATERIAL AND PREPARATION METHOD THEREOF

摘要

A low-temperature, high stability co-fired microwave dielectric composite of ceramic and glass, including 85-99 wt % microwave dielectric ceramic of formula [1-y-z[(1−x)Mg₂SiO₄−xCa₂SiO₄]−yCaTiO₃−zCaZrO₃, wherein 0.2≦x≦0.7,0.05≦y≦0.3 and 0.02≦z≦0.15], and 1 to 15 wt % with Li₂O—BaO—SrO—CaO—B₂O₃—SiO₂ glass respectively made at a low sintering temperature of ceramic for co-firing with Ag or Cu electrode, employing eutectic phase of ceramic oxides to reduce its melting temperature, a low melting-point glass material with high chemical stability as a sintering aid added to oxides and raw material powders of Li₂O, BaO, SrO, CaO, B₂O₃ and SiO₂, obtained by combining and melting the ingredients in the temperature range between 1000 to 1300° C., quenching and crashing, and then adding it to the main ceramic oxides to form the final composition. This ceramic/glass composite material may be co-fired with an Ag and Cu electrode at 900° C.-970° C. for 0.5-4 hours in a protective atmosphere. After sintering, this dielectric material possesses efficacious microwave dielectric properties, dielectric constant between middle-K to low-K at 8⁻15, high quality factors, low dielectric loss, low temperature-capacitance coefficient and superior chemical stability suitable for manufacture of multilayer ceramic devices.