Mechanical property investigation of single polymer particles with different surfactant additive contain for monodisperse polymer particle synthesized

Micro-sized metal coated polymer particles are widely used in the anisotropic conductive adhesive (ACA). For ACF materials in driver IC package application, polymer particles with elasticity and monodisperse are crucial important for the processing and reliability. For this study, different surfactant concentration (SDS; 0.13wt% to 1.25wt%) with high cross linked micro-sized polymer particles were synthesized via seeded polymerization, using divinylbenzene as cross linking monomer and poly(methyl methacrylate) synthesized by soap-free polymerization as seed particles. The mechanical properties of single polymer particle, such as recovery rate, K-values, and breaking displacement were investigated using micro compression test. The relationship between mechanical properties and surfactant concentration of polymerization were studied in the research work. Due to the high temperature bonding process in driver IC package application, the stable mechanical property of particles of ACF at high temperature is important. The high temperature mechanical properties of polymer particles under different surfactant concentration of polymerization conditions were also investigated. The results revealed that high SDS concentration for seeded polymerization the microspheres have lower recovery rate and K values. After high temperature MCT compression test, the polymer particles synthesized with 0.75 wt% SDS concentration revealed partial fracture and with 1.25 wt% SDS concentration the microspheres even appeared entire fracture.