In a message dated 9/15/98 7:19:48 AM Pacific Daylight Time,
[log in to unmask] writes:

<< I am curious, why are the ceramic BGA solder balls not eutectic and made
 with the 90/10 Pb/Sn solder?
  >>

Me too!

     I just ran a board that had a 144-pin micro-bga that appeared to have
high temperature balls on it. I'll usually do a cursory visual check on the
bga devices after reflow by holding the board on edge under a microscope, and
looking at the outside row of balls to see the filleting I'm expecting when
the paste, placement, and profile is in there...however, I didn't see that
with this last board. I reflowed under a profile that I know was good, I
peaked at 219 C. I was almost tempted to bump things up a bit but remembered
that there are high temperature balls out there.

     If the reason is because the device generates the kind of heat that needs
hot balls (this is almost sounding pornographic...hehehe), then should we be
soldering them with a higher temp alloy than a 63/37?

-Steve Gregory-

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