Parallel gap resistance thick wire bonding for vertical interconnection in 3D assembly

This paper manages to obtain the technological parameter by studying the parallel gap resistance bonding of thick wire. Then the connection mechanism of copper and nickel wire on the tin coated copper solder is explored. Thirdly, the temperature field distribution during the process of bonding is also achieved by building the three-dimensional heat transfer model based on ANSYS software. The results indicate that bonding current and bonding time have the greatest influence on the joint strength, and the influence of electrode pressure takes the second place, while electrode spacing has the least influence on it. With the increasing of bonding current and bonding time, the joint strength increases. The bonding essence between Ni wire and Cu pad with Sn film is diffusion welding. There is a very thin layer of Sn under two electrodes which contributes to diffusion. With a higher temperature between the two electrodes, the diffusion is also obvious. The results of ANSYS simulation indicate that the temperature under the two electrodes hasn´t reached the melting point of copper wire, which verifies the essence of the parallel gap resistance welding is not fusion welding.