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74 The PCB Magazine • September 2014 In previous columns I presented the oxide alternative process. As you may recall, oxide al- ternatives function by micro-etching the cop- per foil and co-depositing an organic coating over the copper. It is strongly suggested that the fabricator work closely with the chemical and laminate suppliers to optimize the amount of copper etch (removal of copper). Experience has shown that some laminate material require greater amounts of copper removal in order to insure optimum bond strength. In Figure 2, the condition shown is a separa- tion within the resin itself, not at the resin-cop- per foil interface. So one would troubleshoot this defect differently than if the separation was at the resin-copper foil interface. Delamination within the resin is not an in- nerlayer treatment process issue. This defect is related to the quality of the resin material and the potential for moisture in the resin. Retained moisture in the laminate and resin material has a profound effect with respect to vapor pressure (Figure 3). This is further impacted by the move to lead-free assembly (impact of increased peak temperatures, 210°C > 250°C). In order to prevent moisture from contrib- ROOT CAuSE OF FAILuRES IN PWB LAMINATION continues figure 2: delamination within the resin. figure 3: effect of lead-free temperatures on retained moisture and vapor pressure.