Analysis of the influence of different parameters on dipping

The dipping process of flip-chip is a major factor that influences the quality of product in Microelectronics packaging. It is not acceptable that insufficient or excessive flux attaches to bumps after dipping. To remove these problems effectively, a dipping experimental bed has been established. And the whole dipping process was recorded by high-speed camera. Dipping speed, dipping depth and dipping time all affect the results of dipping. The dipping results under different conditions can be obtained by changing several parameters on LabVIEW user interface. In order to obtain the variation trend of glue quantity, the image from high-speed camera was processed by Matlab. It was found that micelle happened when dipping speed is less than or equal to 0.2cm/s, and the lower the speed, the smaller the dipping depth of causing micelle. For the experimental chip, when dipping depth is smaller than three quarters of bump height and dipping speed is larger than or equal to 0.4cm/s, micelle is removed effectively. At a reasonable dipping depth and dipping speed which means the depth and speed without micelle happening, the glue quantity of flux on bumps increases with increasing of dipping depth, and decreases with increasing of dipping speed. Dipping time is also a key parameter that affects the glue quantity. Micelle also happened when dipping time is up to 10ms, and the glue quantity of flux on bumps increases with increasing of dipping time. But excessive dipping time will cause an unacceptable result.