I have a customer that objects to solder smear. "What" you ask, "exactly is solder smear?" Subsequent to HASL, opportunities exist for boards to come into contact with one another. One example of this would be NC fabrication where panels are stacked and routed. During this contact, the solder features on one panel may transfer solder to the solder mask on adjacent parts . This happens more frequently when there is a high topography soldermask such as SR1000. With low topography masks (LPI) the condition is nonexistent (at least to the un-aided eye) The objection stems from the notion that solder smeared (and we are talking about an extremely low level, barley detectable with XRF) between traces and/or pads creates a spacing violation, causing a potential bridging condition. I have managed to convince the customer to accept this condition at least on the solder side, reasoning that the smear will be removed during wave. They will not, however, accept it on the component side. I would be most interested in hearing from anyone with experience with this condition. I have spoken with the very helpful folks at IPC about this issue. It seems that there is no specification addressing this issue directly. David Pizzoferrato Centerline Circuits [log in to unmask]