Comparing the mechanical and thermal-electrical properties of sintered copper (Cu) and sintered silver (Ag) joints

This review compares the mechanical and thermal-electrical properties of sintered copper (Cu) with sintered silver (Ag) as bonding materials in the microelectronics joint applications. Sintered Cu is explored as a possible replacement for sintered Ag, which suffered from electrochemical migration and high cost. However, sintered Cu faces severe oxidation throughout its product lifecycle, from Cu particle synthesis to joint formation, and finally, post-sinter reliability testing. This review discusses the various sintering conditions and related metallization/treatments to control this Cu oxidation and microstructural evolutions to form a reliable joint (in mechanical-thermal-electrical properties) for as-sintered, thermal aged, and thermal-mechanical cycled conditions. Separately, the patent information showed that the sintered Cu's development and materials paste formulation followed those of sintered Ag closely and often claimed along as one of the sintered elements included in the patents. This review intends to guide new and experienced researchers to this sintered bonding to understand the sintering science, technologies, and related patents on sintered Cu and Ag.