New Double Sided Molded Package Platform Development with Open Cavity Mold on One Side and Exposed Die Mold on the Other Side

System-in-Package (SiP) modules are widely used in portable electronics such as Internet of Things (IoT) and mobile consumer devices. Integrating multiple silicon chips or components into a single package facilitates smaller end products. An advanced packaging technology referred to as Double Sided Molded (DSM) has also widely been proposed as a means of achieving even smaller form factors and lower cost solutions to meet thin stand-off-height. But in case of traditional DSM, the standard structure is the same mold type for bottom side and top side, which used transfer molding for exposed shape or over mold shape. With this approach, it is difficult to meet the requirements for thinner stand-off-height because of the design limitations.This paper presents a new DSM SiP structure with open cavity mold on one side and an exposed silicon die mold on the other side. The new Double Sided Molded package platform can address heterogeneous applications in one package structure by combining the exposed mold with one die and cavity mold with two die stacking. For the assembly process for the new platform, one flip chip die was attached on the bottom side and two dies were stacked on top side. The mold process and epoxy molding compound (EMC) selection are important factors for both the top side and the bottom side to manage the same level of strip warpage. Before process flow sequence optimization, the comparison of strip warpage degree was simulated using an Ansys program. For the material property extraction of the molding compound, the modulus of elasticity and the coefficient of thermal expansion (CTE) were measured by dynamic mechanical analysis (DMA) and thermal mechanical analysis (TMA). In addition, a differential scanning calorimetry (DSC) and a rheometer were used to analyze the curing kinetics and material’s viscosity properties, which are used to analyze mold flowability and void percentage of the EMC. Based on experimental results of material and process analysis, the strip warpage performance confirmed a suitable EMC material and the process flow sequence for end market products of package-level assembly and use in the manufacturing process. To ensure reliability of the new DMS platform, the reliability testing verification includes the Unbiased Highly Accelerated Stress Test, temperature cycling test and high temperature storage test. Reliability tests confirmed that no cracks occurred on the exposed flip chip die from bottom side or to the two dies stack from the top side, respectively. Finally, this paper summarizes the best performance conditions for strip warpage reduction, workability and reliability performance of the new DSM platform. The promising new double side molded package platform (with open cavity mold on one side and the exposed silicon die mold on the other side) has observable differences from DSM with the same mold type for both sides of a SiP structure for use in mobility applications.