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Soldering & desoldering uBGA packages

B

Bozz

Senior member
I have a Nokia mobile phone that I suspect I blew up the charge control IC by plugging in a charger that gives out a higher voltage, I've checked the fuse and various componently around it because I have an identical 8210 phone that works and used it to compare.

Now I am very proficient in surface mount soldering, but only for components & ICs with visible leads that a soldering iron tip can reach. uBGA chips have all leads under the IC (look at a typical chipset southbridge or northbridge if it has no heatsink). I've done a fair bit of hunting for info and I have come up with some pretty useful information but I have found nothing that specifies or directs whether it can be done by hand. Can it be done?

Another question I cannot find by searching is how do you remove that moisture seal around SMDs - it looks like the moisture seal around the core of P3 and celeron coppermine CPUs

I know it is most likely cheaper to replace the phone outright but that is not my perogative, I'm a hardware junkie and would love to repair something if possible. If I totally stuff it up, at least I've learned something.

Are any people able to supply info on how it may be done by hand, could PM possibly assist in some help or answer to the question due to his company making many boards as well as CPUs...

Any info would be greatly appreciated.

Cheers
 
I know of a company that makes a PGA solder mask, but not a BGA. Wow, quite a project. Let us know how it goes.
 
Wasn't there a thread a while ago about soldering surface mount chips with a toaster oven? Maybe it was in the general hardware forum. I've been to NASA soldering school and it sounded pretty plausible to me. A quick Google search on "solder toaster oven" produced a wealth of hits.
 
I always thought the only way to solder BGA was with a reflow oven. Further, I'd heard that some manufacturers (especially those making high complexity, high cost PCBs) were reluctant to use BGA because there's no way to salvage a board with a bad solder join (they also need more expensive QC - a quick visual won't do, the joins have to be X-rayed) - at least with exposed leads and pins bad joints can be reflowed by hand.

Thinking about it, the only way I can see to remove a BGA component is to heat it with a blow torch until the solder melts - bad for the PCB, and probably worse for the device. As to how you'd solder the new device, well, rather you than me - how would you even ensure correct registration?
 
There are BGA removal tools. Especially us fellows who make those high integration, high cost pieces of equipment have them.

In the commodity market, where a mainboard is $50 retail and the process of replacing a large BGA easily exceeds that, you plain and simply throw the thing in the bin. If that mainboard is $5000, then that's different 🙂
The true art in this is to keep the other BGA chips on the same board from falling off whilst you solder the one to be replaced off and back on.

regards, Peter
 
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