Stiffness Effect of Conductive Composite Powder on Electrical Properties of ACF for FPD

• Published in: Metals and materials international Vol. 5; no. 6; pp. 625 - 631
• Main Authors: Kim Tae Sung, Moon Hyuk Soo, Choi Chang Hee, Lee Duck Hoon
• Format: Journal Article
• Language: Korean
• Published: 대한금속재료학회 30.12.1999
• Subjects: AFC; anisotropic conductive film; bounce-up; composite power; conductive C/P; cross-linking density; modulus
• ISSN: 1598-9623; 2005-4149

Elastic moduli of C/Ps were varied to develop an epoxy-based reparable thermosetting ACF for FPD without causing bounce-up in the contact resistance and fracture of the conductive composite powders (C/Ps). The modification of the elastic properties of the C/Ps was done by modulating of the elastic properties of the Polystyrene (PS) bead that is the core of the C/P. The elastic properties of the PS bead changed by cross-linking degree during seeded emulsion polymerization. A simulation based on the experimental results was done to find the optimum mechanical properties of C/Ps for future finer pitch size application. For better simulation, both cases (with/without consideration of interfacial friction and slip) were compared. From these experiments, the following results were confirmed. C/P stiffness was controlled by a change of cross-linking density of the PS bead. The mechanical behaviors between the C/P and PS bead were similar within error range. When the cross-linking density of the C/P was less than 50%, the C/P could be deformed over 40% without fracture. Also, the ACF with a 50% cross-linking density C/P didnt show any bounce-up in C/Ps contact resistance and fracture. Although differences between the cases (with and without consideration of interfacial friction and slip) were observed, neither case matched the experimental result. For a closer simulation, a variation in frictional coefficient is needed.