Improvement of electrical performance of anisotropically conductive adhesives

To improve the electrical properties of the anisotropically conductive adhesive (ACA) joints with the potential for fine pitch interconnect, self-assembled monolayer (SAM) compounds are introduced to treat nano silver (Ag) fillers. Thermogravimetric analyzer (TGA), differential scanning calorimeter (DSC), contact angle and photoacoustic Fourier transfer infrared (FTIR) results indicated the SAMs were well coated on the nano Ag particles. Furthermore, these SAM-treated ACAs were thermally stable at processing temperatures of the ACA samples. By introducing the novel SAM materials into the interfaces between nano metal fillers and the substrate bond pads, the conductivity and current carrying capability of ACAs were improved significantly due to the stronger bonding between nano fillers and SAM and consequently the improved interface properties of the high performance ACA. The improved electrical performance of nano Ag filled ACAs was accompanied with the higher thermal conductivity as well.