| 摘要 |
A process of efficient metal bump bonding with relatively low temperatures, preferably lower than the melting point of indium, is described. To obtain a lower processing temperature (preferred embodiments have a melting point of < 100°C), a metal or alloy layer (138) is deposited on the indium bump (134) surface. Preferably, the material is chosen such that the metal or alloy forms a passivation layer that is more resistant to oxidation than the underlying indium material. The passivation material is also preferably chosen to form a low melting temperature alloy with indium at the indium bump (134) surface. This is typically accomplished by diffusion of the passivation material into the indium to form a diffusion layer alloy. Various metals, including Ga, Bi, Sn, Pb and Cd, can be used to form a binary to quaternary low melting point alloy with indium. In addition, diffusion of metal such as Sn, Sn-Zn into Ga-In alloy; Sn, Cd, Pb-Sn into Bi-In alloy; Cd, Zn, Pb, Pb-Cd into Sn-In alloy can help adjust the melting point of the alloy. |
