Development of low temperature sintered nano silver pastes using MO technology and resin reinforcing technology

Traditional thick film technology is widely used in various electronics products. There are two type of paste based on thick film technology. Typically, over 400°C is required for high temperature sintering type which contains glass for adhesion function. It shows high electrical and thermal performance. On the other hand, 150-300°C range process is used for low temperature process type as silver epoxy. In last decade, nano silver technology shows amazing progress to address low temperature operation by low temperature sintering. This paper will discuss the results on fundamental study of newly developed nano silver pastes with unique approach which uses MO (Metallo-organic) technology and resin reinforcing technology. Nano silver pastes contain several types of dispersant as surface coating to prevent agglomeration of the particles. Various coating technique has been reported to optimize sintering performance and stability. MO technology provides low temperature sintering capability by minimizing the coating material. The nano silver pastes show high electrical and thermal performance. However, degradation of die shear strength has been found by thermal cycling test due to the fragility of porous sintered structure. To improve the mechanical property, resin reinforcing technology has been developed. By adding special resin to the pastes, the porous area is filled with the resin and the sintered structure is reinforced. Degradation of die shear strength was not found by thermal cycling test to 1000 cycles. Nano silver pastes using MO technology and resin reinforcing technology will meet lots of requirement on various thick film applications.