In this paper, thermo-mechanical and rheological properties of NCPs (Non-Conductive
Pastes) depending on silica filler contents and diluent contents were investigated. And then, thermal
cycling (T/C) reliability of flip chip assembly using selected NCPs was verified. As the silica filler content
increased, thermo-mechanical properties of NCPs were changed. The higher the silica filler content was
added, glass transition temperature (Tg) and storage modulus at room temperature became higher. While,
coefficient of thermal expansion (CTE) decreased. On the other hand, rheological properties of NCPs were
significantly affected by diluent content. As the diluent content increased, viscosity of NCP decreased
and thixotropic index increased. However, the addition of diluent deteriorated thermo-mechanical
properties such as modulus, CTE, and Tg. Based on these results, three candidates of NCPs with various
silica filler and diluent contents were selected as adhesives for reliability test of flip chip assemblies. T/
C reliability test was performed by measuring changes of NCP bump connection resistance. Results
showed that flip chip assembly using NCP with lower CTE and higher modulus exhibited better T/C
reliability behavior because of reduced shear strain in NCP adhesive layer.