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60 PCB007 MAGAZINE I MAY 2023 current distribution, especially when the cath- odes (boards) are moving on a vertical or hori- zontal conveyor. Solution and Work Agitation Eductors for high-solution agitation began with flo-motion manifolds in the mid-1970s. e performance progress has been increasing ever since, particularly with new fluid nozzles providing better solution distribution with- out the introduction of air. Higher laminar flow equates to higher solution exchange and fluid dynamics, especially in confined spaces or blind vias. Work agitation has improved with the Z-axis added for better fluid distribu- tion and reduction of entrapped micro-bub- bles. Fluid dynamics is controlled by improved pumps, filters, and integrated support equip- ment (Figure 3). Transport Systems: Vertical Conveyors and Hoists Laser distance units were first employed by Hewlett-Packard's PCB facility in Loveland, Plating Cell Construction e basics have not changed much, but several innovations have been added. ese include: Anodes and Cathodes One of the biggest innovations is the insolu- ble anode, constructed out of titanium or irid- ium oxide-coated titanium electrode and the anode membrane (Figure 1). Soluble, phos- phatized copper anodes can introduce partic- ulates and limit the ability to control plating distribution. Insoluble anodes are known to eliminate the particulates, provide consider- able anode area, and the anode can be shaped to match the plated part. When matched with solution inductors and anode membranes, they limit additive breakdown and consump- tion normally seen with the soluble anode surface. Segmented Anodes Another innovation is the segmented anode (Figure 2). It showed much better control of Figure 2: The use of segmented anodes, in conjunction with separate DC or pulse-plating power supplies, allows much finer control of cathode current densities and distributions. This is very important for newer copper via filling chemistries and for apparatus that employs conveyorized cathodes (panels). (Source: Atotech 2 and Ludy 3 ) a b