Kevin,

Make a shear test and see what's up. If the component has at least some 100 N/mm2 per
'leg', then the solder may not be so bad. If there is a real bad joint, I'd look for
dewetting, which is far from rare today, when the component makers try to lower
the processing costs.

My two centimos

Ingemar Hernefjord
Ericsson Microwave Systems



-----Original Message-----
From: TechNet [mailto:[log in to unmask]]On Behalf Of Kevin Jaworenko
Sent: den 1 december 2004 15:44
To: [log in to unmask]
Subject: [TN] Help, Help, I have a QFN Package I don't know what to do!


G'day Everyone.

        Well as the subject states we are currently running a prototype
assembly with a new package style to me, a QFN (Quad Flat No-lead). I had to
look that one up myself.

        The problem is when we were trying to reflow the part, the solder
joint looks very poor, with little to no solder seen on the edge of the
component lead and the pad on the PCB, or a bubble of solder seen on end of
the component between the edge of the component lead and the pad of the PCB.

        I'm currently setting up to X-ray the components to see if the foot
actually has a good solder joint underneath the component, where the lead
has been curled around the component, but has anyone else had any dealings
with this particular component type before and would be willing to share?

        I looked up the component manufacture's website and they show that
this component has a required peak temperature of 235 (+5/-0) degrees C.
That seems like a lot of heat for a non lead-free component.

        Feel free to email me offline if anyone likes.

Thanks in advance.

Kevin Jaworenko
Manufacturing Engineering Technologist
Vansco Electronics LP
(204) 453 - 3339 ext. 622
(204) 453 - 3663 FAX
[log in to unmask]


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