Flip Chip and RDL Design

Summary

Flip chip (FC; also called invert welding) is a new type of micro‐assembly technology. In recent years, flip chip has become a frequently used packaging format in the field of high‐end devices, high‐density package and SiP. On the one hand, flip chip greatly shortens the length of the signal interconnection, reduces the delay, and effectively improves the performance, which is important for high‐speed design. On the other hand, because of the use of planar array connection, flip chip interconnection can provide higher I/O density. Redistribution layer (RDL) involves making a layer on the active chip side, for chip pin redistribution. With RDL, chip pins can be rearranged to any reasonable position on the chip. Using RDL technology, the die pads located in the chip periphery to support traditional wire bond technology can be reassigned to the "redistribution pins" of the chip anywhere on the surface.