Optimisation of Slurry Compositions for Improving the Mechanical Properties of Low Temperature Co-Fired Ceramic (LTCC) Tapes

Abstract

Abstract In the era of miniaturization and hybridization, the quest for novel materials for multilayer packaging had been increased. The multilayer packaging includes High Temperature Co-Fired Ceramics (HTCC), LTCC and ULTCC. LTCC which is the mixture of ceramic and glass (which reduces the firing temperature of ceramics) has attracted many researchers due to its lower firing temperature(<900°C). Due to this lower sintering temperature, it can be cofired with the low resistance metals like Ag and Au which increases its value in multilayer packaging field. The standard package fabrication process uses LTCC in the form of tapes. Each layer can be processed separately for punching, via filling and Screen printing and then stacked, laminated and sintered to get a multilayer package. The green sheet of LTCC should have sufficient adhesion to carrier film as well as mechanical properties to withstand the fabrication processes that it undergoes. These properties are mainly affected by the organic compositions used in the slurry preparation. The tape casting slurry was prepared by blending the LTCC powder with solvents, dispersants and binders for a predefined time in ball mill. The as prepared slurry was casted on a Mylar sheet in a continuous tape caster for varied thickness. The present study aims at reporting the effect of plasticizers and binders on the adhesion and mechanical properties of the tape. The starting material which was the mixture of Cordierite and Anorthite based recrystallizable glass was prepared through solid-state method. The powder was then characterised for its phase purity, microstructure and elemental compositions using XRD, FESEM and EDAX. The green tapes were characterised for its thickness, uniformity, green and sintered density, surface defects such as pinholes and cracks, adhesion and tensile strength. The dielectric properties as well as thermal properties are also evaluated. The results are reported.