Copper RDL is an interconnect technology used in both fan-in and fan-out wafer level processing. It allows high-density I/Os to be redistributed for connection to the circuit board by increasing the pitch.

Additionally, the purity of the Cu formulation reduces manufacturing costs by eliminating the nickel barrier between the copper and solder elements required by other plating approaches to control topography and eliminate defects.

Driven by mobile applications that require increased functionality at lower power, RDL requirements are tightening from 5 µm line/space to 2 µm line/space. This calls for plating chemistries that can achieve high reliability with low-within-die uniformity.

The function of additives in RDL plating is similar to those in Cu pillar plating. DuPont’s INTERVIA 9000 plating chemistry can be used for both RDL and Cu pillar plating in one plating tool without changing the plating bath, making it an economical choice.