Re: gEDA-user: OT: soldering QFN packages with exposed bottom pad?

[Bob Paddock <graceindustries@xxxxxxxxx>]

> Got any recommendations for how to hand-solder a QFN package that has an
> exposed bottom pad?  At the moment, all I have is a soldering iron.
>
> Do you think I could just put a plated-through via underneath the pad,
> and then flow solder through that from the back side?

That is fine for hand made boards.  On a reflow production line, such a hole
tends to suck the solder into the hole, with little to none left for the part.
Our production tech. tells me that BGA's are easier to deal with than QFN's.

QFN's can also have problems with getting the flux washed out from
under the part.

Take a look at this article on QFN soldering:

http://www.wirelessnetdesignline.com/202800018


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