Low temperature interfacial reaction in 3D IC nanoscale materials

In this review, we cover copper-to-copper (Cu-to-Cu) direct bonding, point contact reaction between silicon (Si) nanowire and metal nanowire, and cold welding of gold (Au) and silver (Ag) nanowires. All of them occur under nanoscale interfaces at low temperatures. For a broader consideration, because Cu is known to exhibit significant anti-pathogen and anti-viral properties, the interfacial reaction in Cu nano-grain metallurgy may be used to manufacture Cu and Cu alloy products to reduce virus transmission, which can have a very large impact to our society. Furthermore, in the future semiconductor technology, because of dense packaging, Joule heating will be serious. Thus, low entropy production process will receive attention, which means low temperature joining technology such as cold welding and nano-welding will be important.