Strip Warpage Assessment of Dual Side Molding SiP Module

SiP modules, integrates multi-function components in a package, are widely applied in consumer electronics and IoT, such as Wifi module, GPS module and RF module, etc. Dual side molding module is a more advanced device type, who integrate all the components on the both surfaces of the substrate to effectively reduce the module area. By process strip warpage control is one of the crucial matters for assembly in order to have good yield and high automatic manufacture efficiency. Finite element method is a powerful tool for strip warpage evaluation; however, dual side SiP module strip requires enormous elements to describe its details. A useful model simplification method was proposed in this study. The several layers substrate was simplified as a homogeneous material by numerical tensile and thermal expansion tests to obtain the substrate bulk material properties of modulus and thermal expansion coefficient. The simplified substrate not only helps for efficiency computing, but also can be a transition zone for the different component layout of top and bottom substrate surfaces successfully mesh in the simulation model. Birth and death method was used to investigate by process strip warpage, the evaluation results help to reduce the risk comes from strip warpage. According to the well validated simulation model, for process improvement, firstly SMT and molding top side has better performance for strip warpage; for EMC improvement, bottom side choose high shrinkage EMC or top side select low shrinkage EMC can well control strip warpage.