Adhesive and Mechanical Properties of Nano-Particle Filled Thermoplastic Polyimide Dielectric Films for Microelectronics Packaging

In this study the mechanical and adhesive properties of aluminum nitride (AlN) nano powder filled polyimide composite films (AlN-PI) are investigated to determine their usefulness as dielectric materials in microelectronic packaging. AlN nano powder was mixed in low wt% during synthesis at poly(amic acid) (PAA) stage. AlN-PI films were characterized using DMTA and tensile testing to determine viscoelastic behavior and mechanical properties. Adhesive strength of bonded samples was determined using single lap joint tests. The fractured surfaces were examined by scanning electron microscope (SEM) to determine failure patterns. The results showed that viscoelastic behavior of AlN-PI films changes from liquid-like to solid-like with increasing AlN content. Elastic modulus and strength at break of nano particle-composite films were found to increase with increase in AlN wt %. However, elongation at break and breaking energy of films and lap shear strength of bonded samples were found to initially increase with increase in nano particle wt%, but then after a critical value decreases