Optimization of Temporary Carrier Technology for HDFO Packaging

This study investigated how the outgassing from the epoxy molding compound (EMC) affects the backside bumping process in a High-Density Fan-Out (HDFO) package and focused on process changes to minimize it.A bonding material selection design of experiments (DOE) was performed. It included mass spectrum analysis for mold outgassing components, an evaluation for mold bake conditions and queue (Q)-time to define the optimum wafer support system (WSS) conditions. Findings conclude that during mold bake, inserting a barrier layer on the wafer and Q-time from barrier layer to WSS are very crucial factors to suppress the mold out-gassing.The optimized WSS technology was applied to an HDFO package, and its effectiveness was confirmed through feasibility and reliability testing.