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12 The PCB Magazine • May 2014 by Michael Carano om GrouP electronIc cHemIcals, llc F e a t u r e Introduction The technology trends are unmistakable (Table 1), such as the need to move into higher functionality while reducing footprint of the PWB substrate. In turn, this triggers circuit designs with smaller vias, blind, buried and stacked vias, as well as any-layer technology. In addition, there is a call-out for more flexible and rigid-flexible printed circuit boards. Com- plicating matters for the fabricator is the prolif- eration of material sets designed to support the low-loss, high-frequency market segment. With all of these changes, along with heightened em- phasis on end-product reliability and produc- tivity, metallization performance is under the highest scrutiny. Direct Metallization Direct metallization of boards is a predomi- nant process in flex circuit and microvia manu- facture. This conveyorized process is fast and ef- ficient. However, in North America, direct met- allization is not as common as in overseas mar- ketplaces, most likely reflecting the higher per- centage of flex and microvia in the production mix. Regardless, direct metallization processes (most) offer lower consumption of resources over conventional electroless copper. This in- cludes reduced rinse water and waste treatment concerns, lower power consumption as well as fewer chemical processes to maintain. For most direct metallization systems including graph-