Application of composite binders in the fabrication of LTCC green tape based on the borosilicate glass/Al2O3 system with optimized Ca/Mg ratios

This study aimed at developing a high-performance low temperature co-fired ceramic (LTCC) green tape with good sintering characteristics and dielectric properties based on a borosilicate glass/Al2O3 system. First, the Ca/Mg ratio in the glass composition was optimized to modify the microstructure, sintering density, and dielectric properties. Subsequently, composite binders of various molecular weights were employed in the tape casting slurries, to improve the performance of the green tapes. Following a comprehensive analysis of the multiple necessary performance parameters, we concluded that the glass/Al2O3 composite with Ca/Mg = 4.30 sintered at 875 degrees C presented a dense microstructure with outstanding sintering characteristics and dielectric properties (density of 3.14 g/cm(3), permittivity of 8.02 and dielectric loss of 11 x 10(-4) (10 MHz)). The application of composite binders with 60% B20H and 40% B79 yielded a green tape with a high density (1.94 g/cm(3)), smooth surface (Ra = 213 nm), and good workability. In addition, the thermal and mechanical properties of the optimized composite were practical for electronic packaging applications. This positive assessment of the co-firing compatibility between the composite and Ag electrodes augments its application potential for LTCC technology.