Brad Velander wrote:
>Jon, > Sounds like you had soldermask that wasn't over bare copper. With the > SMOBC you shouldn't have that problem. With solder plated traces (some fabs > used to use that as their etch resist, I didn't know anybody was still doing > it) under soldermask you will definitely have that problem. > That may well have been 10+ years ago, I just remember seeing this happen. > Regardless, if you specify SMOBC this shouldn't happen to you. > Otherwise it is exhibiting poor mask adhesion or something in your assembly > processing is out of whack. > > Pattern plating is whole other fish that isn't related to finishing or > soldermask. > > OK, I guess I have forgotten the name of the process using the solder as the etch resist. I guess that is called solder resist. I seem to recall a process where a laminate with a very thin foil is masked with a negative resist pattern, and then copper plated until the desired trace thickness is built up. Then, the exposed trace surface is (electro)plated with solder. Then, the resist is stripped, and a quick dip in etchant removes the thin foil, leaving the solder-plated traces isolated. This process accomplishes both the through-hole plating and the defining of the traces in one step. I thought this process was called pattern plating, and most fabricators leave the solder plating on the traces, and then solder mask it. Jon ____________________________________________________________ You are subscribed to the PEDA discussion forum To Post messages: mailto:[email protected] Unsubscribe and Other Options: http://techservinc.com/mailman/listinfo/peda_techservinc.com Browse or Search Old Archives (2001-2004): http://www.mail-archive.com/[email protected] Browse or Search Current Archives (2004-Current): http://www.mail-archive.com/[email protected]
