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BGA on conformal coated PCB

Kris

#27236

BGA on conformal coated PCB | 12 February, 2004

Hi all,

We have a PCB without any BGAs on it which goes into harsh environment.We therefore conformal coat it. After assembly the PCBs are expected to withstand "85degc/85%RH for 1000 hours"

We now want to add a BGA to the PCB. Does any one have any idea for this application. What can we do to coat the BGAs ?

Any previously published papers for similar applications ?

Thx

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blnorman

#27238

BGA on conformal coated PCB | 12 February, 2004

Why can't you conformally coat the BGA? We do on some of our lines with no adverse affects.

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Kris

#27246

BGA on conformal coated PCB | 13 February, 2004

we are worried about the coating not being able to cover underneath the BGA. If the coat is excessive then it would cause CTE issues.

Also if anybody has data on 85/85, 1000 hrs after conformal coating of BGA, would appreciate if you guys can share it with me.

Thanks for letting me know that the process can be done

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roertner

#27248

BGA on conformal coated PCB | 13 February, 2004

You might want to check int using a BGA underfill material prior to coating.

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blnorman

#27256

BGA on conformal coated PCB | 13 February, 2004

Underfills could improve reliability. If you pick materials right, you could co-cure and underfill and coating.

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