hi,

this reminds me of a situation we were in several years ago when we were using pin grid arrays.  the customer required that we microsection the first, middle, and last assemblies coming out of the wave solder machine, so that we could verify that we were getting acceptable solder fillets on both sides of the pga plated-through-holes.  i suggested that our lot size should be three.  this would enable us to assemble these boards forever.  unfortunately, no one here thought that was a good idea.

what you could do is ship your assemblies with the bga's sheared off, but with the heat sinks still attached to the bga's.  this would enable you to build these parts forever.  i've got a feeling though that this wouldn't be acceptable, but it would get the attention of your customer.

phil



-----Original Message-----
From: Carl Ray [mailto:[log in to unmask]]
Sent: Wednesday, March 13, 2002 8:17 AM
To: [log in to unmask]
Subject: [TN] Solder Joint Mechanical Stress


I have a customer who is requiring that I verify the bond strength of a
heat sink that is glued to the top of PBGA. The customer has supplied me
with a torque tool to verify the strength of the bond between the heat
sink and the BGA. I have concerns that testing the strength of the glue
bond may affect the solder joint reliability of the BGA. The tool
supplied by the customer is set at 20 in pound torque. Any ideas how I
can "change" my customer mind?

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