Hello..
Does anyone know if there is an IPC standard for solder content on the back
of PCBs?  My application is RF/Microwave filters mounted on PCBs.  There are
components only on the top side and plated thru vias in various places on
the PCB (for grounding, etc.).  The bottom of the PCB has no soldered
components and the PCB is FR-4 with 1oz Copper, Nickle barrier and Gold
plating on both sides.  Solder mask is on certain PCBs, and can be used to
help prevent solder from penetrating to the bottom of the PCB.

The problem is for solder (during reflow) finding it's way from the top of
the PCB (where the solder paste is applied) down through the plated thru
vias to the underside of the PCB.  This solder is not enough to cause a
solder ball or make the part fail for mechanical height specs, yet it is
more of an aesthetic issue.  Even if the solder is thick enough to be wicked
off, there is still a solder splash or stain on the plating.  Is there an
IPC (or other) spec for solder aesthetics??  If so, what number is it and
what is the price for the document?

The only solder IPC specs I can find seem to deal with solder fillets, etc.
for through hole mounted parts that have a component or components mounted
thru the PCB and soldered on 1 or both sides.

Tnx

Matthew Steger
Product Design Engineer
RF/Microwave Products
Spectrum Control, Inc.
* Phone: 717-361-4842
* Fax: 717-361-4756
* Email: [log in to unmask]
* Mailing Address: 1595 S. Mt Joy St., Elizabethtown, PA 17022