Re-heating BGA Chips

[JohnCT]

Originally Posted by kf4rca

Thanks. I'll give that a try. This BGA has an aluminum heat sink. Should I take it off first?

Yes, if it seems like it can be taken off without a lot of force. Heat up the heat sink first and see if it will come off without too much effort. You most certainly do not want to put too much pressure on the BGA and damage the foils beneath it.

If it seems like it's bonded too tightly, go ahead and reflow as is. The aluminum sink should transfer the heat pretty well.

BTW, if the BGA is a metal one (like a Broadcom), my understanding is that the *inside* of the BGA needs the reflow, not the bottom where it meets the circuit board. Supposedly, these ICs have two dies that are solder balled together, and these will fail internally. For these, less heat is actually required because inside of the chip will reach reflow faster than the bottom of the chip at the board will.

John