Preparation Of Silver Nanoparticle And Its Interconnection Performance

With the development of high-power electronic components, thermal interface materials play an important role in the electronic industry. Due to the limits of solder and conductive adhensive, they can't meet the need of high-power electronic components. Silver nanoparticles can be sintered at low temperature due to its nano-scale which can provide high surface activity and lower the sintering temperature. The conductivity of silver is higher than any other materials while the thermal conductivity is best in metal. The content of this thesis are the preparation of silver nanoparticles and study of its interconnection.Silver nanoparticles are prepared by reduction method in liquid phase. There are two kinds of liquid phase, one use ferrous sulfate as reduction agent, the other use ascorbic acid. The silver nanoparticles prepared by thess two kinds of liquid are very different from each other. The spherical silver nanoparticles prepared by ferrous sulfate and sodium citrate solution which distributed between 20~50nm is more appropriate to use.The interconnection of boards using silver nanoparticles mainly depends on the precipitation of silver nanoparticles and silver coating of board. The shear strength of board interconnected by silver nanoparticles sintered at 150℃is 16.12MPa while 23.26MPa at 200℃. The fracture cross-section is not fixed and the fracture appeared in the weakest position. All of these proved that the silver nanoparticles sintered at low temperature have very high connection strength.Observation of the cross-section and interface of sintered silver layer in different position proved that there are no obvious defects, so the connection is in good condition. The thermal conductivity of silver nanoparticles sintered at 150℃was 37.83W/(m.k) while 31.49W/(m.k) at 200℃was still higher than that of conductive adhesive. The thermal conductivity still needed further improvement.The results showed that the shear strength and thermal conductivity of silver nanoparticles sintered at low temperature is better than that of conductive adhensive. The sintering temperature of silver nanoparticles is lower than the conventional silver paste. All of these prove that silver nanoparticles as a new kind of thermal interfacial materials has a bright future.