Spherolyte RDL / Pillar 2 process for high-speed plating of copper pillars and redistribution layers (RDLs) is a sulfuric acid-based three additive copper electrolyte system. Nonuniformity value – within wafer, die or/and profile – of the deposited copper structures, even over a range of applied current densities, is up to 17.5 ASD  (3.9 µm/min). Process control is analyzable through an online system for all additives. Is for flip-chip applications for various sizes of copper pillars (including µ-Pillars), especially for handhelds such as tablets or smartphones.

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