The Role of Liquid Molding Compounds in the Success of Fan‐Out Wafer‐Level Packaging Technology

Semiconductor packaging technologies are state of the art for various industries and applications including automotive, machinery, entertainment, communication, sensor, security, authentication, medical and environment systems, and many more. Generally, epoxy molding compound is a solid-type resin, which consists of epoxy and phenol chemicals and was originally developed for transfer molding systems. In contrast, liquid-type epoxy molding compound (LMC) was developed for several specific applications that inevitably require a liquid state such as unique flowability and/or a dust-free requirement. Fan-out wafer-level packaging demands several specific characteristics from an LMC encapsulation material. LMC has significantly lower viscosity than solid epoxies in the molding process. In addition, redistribution layer processes require low die-shift performance of LMC. Generally, a liquid molding compound consists of epoxy resin, hardener, filler, and some additives such as coloring agent, accelerator, adhesion promoter, and further special chemicals as required.