Alignment between subsequent 3D molding layers for optimized performance of 3D integrated patch antennas for advanced sensing applications

In the context of Fan-Out Wafer Level Packaging (FOWLP) has gained significant momentum in the market in recent years, as it meets the substantial demand for miniaturization and offers exceptional scalability, as well as electrical and thermal performance. Herein, compression molding is a standard process to encapsulate microelectronic components, which serves the purpose of protecting components from mechanical stress, as well as moisture and contamination. Furthermore, it provides the necessary area to fan out electrical contacts to route signals within the package. Commonly used materials are highly filled epoxy resins (epoxy molding compound, EMC). Recent research has been focused on the exploration of 3D-compression molding, with the objective to deploy nonplanar shapes to enable the potential of 3D freeform antennas, which allow for a significant increase in the field of view (FOV) [1]. For this, multi-step 3D molding is required, as ground and signal metallization layers, formed utilizing direct Cu metallization, are separated by EMC. Accurate alignment between subsequent molding layers and hence corresponding Cu layers (ground and signal) is required for proper performance. In compression molding, such alignment steps are typically not required. We investigate various alignment concepts to achieve accurate alignment in lateral (x-y) direction. By thorough evaluation of achieved tolerances for the respective concepts, we propose preferred options for advancing multilayer 3D molding approaches. This will ultimately enhance the performance of 3D integrated antennas and enable the extension of this approach to applications beyond package integrated antennas.