Advanced Dielectric Materials (Polyimides and Polybenzoxazoles) for Fan‐Out Wafer‐Level Packaging (FO‐WLP)

This chapter provides an overview of advanced dielectric materials developed by HD Micro Systems (HDM) that are based on polyimide (PI) and polybenzo‐xazole (PBO) technologies and that are targeted for use as redistribution layers (RDL) in fan‐out wafer‐level package (FO‐WLP) applications where lithographic and reliability performances are important requirements. The first PI products for semiconductor applications were introduced in the early 1970s for use as stress buffers or passivation layers on integrated circuits as well as interlayer dielectrics in high density interconnects on multi‐chip modules. It is well known that dielectrics based on PI and PBO technologies are widely used as RDL in fan‐in wafer‐level packaging (WLP), flip‐chip chip‐scale packaging (FCCSP), and other applications to relocate I/O connections and reduce stress as well as allowing die stacking. The chapter details the process flow, lithography, material properties, and reliability performance that have been generated for PBO‐Gen3 to date and where PBO‐Gen2 is used as a reference.