Hello Everybody,

     Continuing with this OSP thread, I received an email from an associate
that I would rather keep anonymous to prevent any negative repercussions from
happening. Let's just say I know this individual knows the process extremely
well. Here is that persons input:

"What I wanted to bring up about the Entek is that most fabricators using the
"batch" method (dip tanks) either drip dry or use a tabletop type conveyorized
dryer.

As the component pitch gets finer and denser, the ability to hold entek
coating thickness becomes more and more difficult. The conveyorized dryer may
also have some solutions splashing around as they are dried away from the PCB
(including what may blow out of the small vias).

A good example is BGA vs CSP. The standard BGA pads (1.27mm pitch) may
adequately dry and have a fairly uniform thickness between all device pads.
Now consider CSP padsize. If a drop hits the larger BGA pads, it will probably
spread out thinner and dry away faster than if splashed onto a CSP pad. The
CSP pad variation appears to be greater. High power driers with special angled
air nozzles may be necessary to adequately dry the finer type pitch devices."

Which, by what I read into it, says that you do need a controlled, automated
process in order to achieve a consistent coating thickness. You may or may not
experience solderability issues depending on the design of the board being
coated, and the method that was used to apply the OSP...

-Steve Gregory-

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