Saul,

One of our contract manufacturer's has also seen this phenomenon.  We are
still trying to figure out the cause.  What is the board's floor life
between 1st and 2nd side reflow?  Maybe the PCB/BGA's are reabsorbing
moisture.

joe

-----Original Message-----
From: Saul MorenoRodriguez [mailto:[log in to unmask]]
Sent: Wednesday, March 09, 2005 7:15 PM
To: [log in to unmask]
Subject: [TN] Voids

Hello Technetters:

In a recently running we had a problem with voids in Micro BGA's.
We resolved succesfully only increasing the preheat and the soak time,
this to dry the humidity correctly in the devices.

But my doubt is here:
The Micro BGA's are placed on first side and in first reflow we didn't
have problems,
all was ok, but voids showed up in the second reflow .
We detected them in 5DX.

Could you tell me why this happened ?

Thanks in advance..

Saul Moreno R.
Process Engineer

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