When dealing with BGA chips featuring a pitch as fine as 0.5mm or even smaller, what are the recommended practices for effectively breaking out all the connections? Currently, I’ve been using dead-bugging methods, but I find it to be quite time-consuming and it has resulted in damage to some of the chips. Any advice on more efficient and safer approaches would be greatly appreciated.
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Wow! If you’re dead-bugging BGA’s you’re a rock star. I’m pretty good with an iron and delicate work, but that’s almost through the roof, so I’m not surprised you broken a couple. When you talk about breaking out all the connections I immediately thought of a book I purchased some years back. It’s called “BGA Breakouts and Routing” by Charles Pfeil and published by Mentor Graphics.
But if you’re talking prototypes, debugging, evaluations type of work, the thoughts pop up in this order: 1) Sockets. If there is an available socket for your device it could save tremendous time, money, and sanity. If you’re not sure or don’t know how to find one I’d start by asking the chip manufacturer. You probably won’t be the first to ask. 2) Daughter/breakout/interposer boards. There may be an existing design you can use, but you may have to roll your own. But it will come in handy every time your design gets rev’d and probably for new designs as well as long as your using the same family of chips. There may also be a probe card or ATE card available you could use.
One of the more difficult (impossible?) problems you have with dead-bugging is you can’t possibly test it at speed. The parasitics will screw up the impedance royally, and the wires will contribute to both radiated EMI and act as antennas picking up every stray radiated signal from light switches to 5G phone traffic.
So while I envy your skill you probably are fighting a battle you can’t win.
If you need a place to start when looking for sockets (or building your own, I’ve done that) checkout Emulation Technologies. They have lots of clever things (like pogo pins) for a guy like you.
One last thought - keep “what” you’re trying to test at the front of your mind. If your analyzing current draw, simpler solutions might help, but if your trying for a BERT or Eye Diagram you’ll probably stuck with traditional step-by-step, painful, main stream testing processes.
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