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Selective BGA ball removal

MarcS

#26209

Selective BGA ball removal | 29 October, 2003

Our design team have got a problem. We need to either drill out 6 vias/pads for a BGA site, or remove the solder balls form the BGA before they are palced. ( std eutectic) Has anyone used a vendor to remove balls from BGA (0.75mm piutch, ball size apporx. 0.5mm) then placed them in prodcution? Am I being a bit ambicious. I know that wld be eaiser than reworking/removing copper traces/pads. Any advice would be appreciated, and vendors to do this work wld also be appeciated.

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#26210

Selective BGA ball removal | 29 October, 2003

We here at Precision PCB Services, Inc. Perform selective ball removal. We just completed a job today where we removed 4 balls, and then installed traces to dog-bone the pads at two locations on 30 BGA's.

An eaisier and more cost effective solution would be to just apply solder mask over the pads that you want to eliminate contact with, then install the BGA. No need to remove balls or cut pads and traces. Just insulate the connection with solder mask.

Our Web site is: http://www.pcb-repair.com

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Grant Petty

#26211

Selective BGA ball removal | 30 October, 2003

Hi,

Another option we have used here in house is to remove the unwanted BGA balls with solder wick, and then to manually place them on the PCB foot print. This eliminates the pick and place machine's optical centering freaking out because the balls are missing.

It seems scary, but BGA's self center, and we have never had a problem with gently placing them in roughly the correct spot on the PCB, and then nudging them into position with some tweezers on the corners. The overlay is normally good enough to get the BGA centered quite well on the foot print.

Then when you put the board into the oven, all the components reflow ok, and any slight misalignment will correct itself.

This should be fairly easy to do in-house.

Regards,

Grant Petty Blackmagic Design

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G S

#26212

Selective BGA ball removal | 30 October, 2003

Contact Process Sciencies at 512 259-7070 and talk to Steven Schoppe. He can help you with that problem

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Marc

#26244

Selective BGA ball removal | 4 November, 2003

Marc, I agree with Dennis. Your best method is to apply solder mask over the pads, then install the BGA. You can also remove the balls or completely remove the pads, but it take a skill person to do it. We do all that type precise rework in Southern CA.

www.artek-mfg.com

Thanks

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Don A

#26302

Selective BGA ball removal | 7 November, 2003

It would depend on how many boards and parts you need to build. I would prefer an etch cut as it leaves the the part intact and you get the strength of the solder joint. It also reduces the handling of the BGA and associated damage from that

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