Werner, here are some pictures I took of a castellation component that
comes in gold plated (like most of this style) and I was training
individuals to remove and replace in the field and found several solder
joints like the ones in the pictures where it appears that wetting or
bond did not occur. In your opinion is this an example of the "head in
the pillow" The first two pictures are of the board and the last three
are of the components removed.  I did not want to mix these joints with
the discussions, Thanks, Jon

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Werner Engelmaier /*
Sent: Friday, January 18, 2008 6:58 AM
To: [log in to unmask]
Subject: Re: [TN] SV: [TN] SV: [TN] Solderability of Tin-Gold
Intermetallic

Hi Bev,
Just like George, I am struggling getting an understanding of you
problem.
To me, 'head-on-pillow' solder defects are almost always caused by 
insufficient peak temperature.
If these HOP's occurred essentially near the center of the BGA, you have
your 
answer,
If the HOP's are distributed over the whole array, than the root cause
is not 
insufficient peak temperature unless the whole reflow process is too
low.



Werner



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