Effect of die shape on die tilt in die attach process

Die attach process is widely used to realize the connection between die, device and the rest of the system in electronic packaging. During this process, the die moves under the capillary force induced by the liquidus solder. Such a die tilt phenomenon usually occurs and strongly worsens the reliability and performances of devices. In this paper, we built a numerical model based on fluid minimal free energy theory for analyzing the die arrangement in die attach process. By this model, die arrangements of three kinds of die shapes in terms of square, square with round corner and circle were calculated. Results indicate that compared to the square, both square with round corner and circle benefit preventing the die tilt. Especially, the circle die can well keep the parallel die arrangement.