Flow modeling and visualization of the transfer molding of plastic ball grid array packages

Recent advances in computer-aided tool design have reduced the cost of expensive prototype tooling. CAD-based software has been promoted for the design of plastic IC encapsulation tooling, but until recently, no real-time data from the encapsulation process had been collected to verify its effectiveness. A novel approach was used to capture the plastic IC encapsulation process. A 24×24 mm PBGA mold was equipped with a window and video camera to capture the encapsulation process. Computer simulations of the cavity were also performed, using a new reactive 3-D flow simulation software suite. Computer predicted results showed only partial agreement with the observed molding results due to simplifications of the model required for timely simulation runs. More detailed models would provide better predictions at the cost of lengthy computer CPU time