High Performance Heterogeneous Integration on Fan-out RDL Interposer

The fan-out packaging technology has recently been adopted in mobile application processors due to its advantages in form factor, fine pitch traces, and efficient thermal dissipation. This paper demonstrates heterogeneous integration on a fan-out redistribution layer (RDL) interposer. The package has a full-reticle size Si die and two HBMs. Si die and memory modules are attached to a fanout RDL and are then attached to a multilayer substrate. This advanced package meets both electrical and mechanical requirements. The fanout RDL interposer is comprised of polymer and copper traces, and it is relatively mechanically flexible. Such flexibility enhances C4 joint integrity, and allows the new package to scale up its size to meet more complex functional demands.