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Void control

Views: 1475

#67487

Void control | 11 October, 2012

We are experimenting with void control in reflow and have had pretty good luck for the most part in attaining Class lll IPC spec. but we have seen a sudden increase in voiding on a specific product and I was wondering if anyone has seen this extreme voiding before? We were wondering if this is due to the microvia design? Thank you....anvil....

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#67488

Void control | 11 October, 2012

Are the microvias in the BGA ball pads?

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#67489

Void control | 11 October, 2012

Yes they are but not durectly in the center,I was also noticing that even our passive components have voids where the microvias are? As a matter of fact there are up to 5 microvias in the passive pads?

There was a previous design that had the microvias as well, but we didnt see this issue?

Thanks for asking....anvil

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#67504

Void control | 15 October, 2012

You could pay the extra to have the microvias plated shut and planarized.

If your voids are larger than 25% of the BGA joint area then I would suspect a solderability problem. Either the board plating or a solder paste problem. If they're less than 25% (or, to be honest, less than 35% since there's no reliability degradation) I'd ignore them.

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#67505

Void control | 15 October, 2012

These microvias were plated shut? Could there have been some out gassing of these plated shut areas during reflow?

I agree with your void % assesment unfortunately my Superiors do not...

Thank you for the input.....anvil

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aj

#67506

Void control | 15 October, 2012

have you xrayed any of the BGA's before you reflow them?

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#67507

Void control | 15 October, 2012

No we havent Xrayed any before reflow, but when we attach the BGAs with just flux they are void free? Thanks....anvil

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Reflow Oven

Essemtec Spider SMT Fluid Dispenser