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Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


Mirrored BGA Assembly

Yngwie

#29520

Mirrored BGA Assembly | 16 July, 2004

We have massive void problems on one of the BGA populated on the bottom side of the board. The board have 6 BGAs on the top and 1 on the bottom. No voids were observed during the first reflow (we reflowed bottom side first), but after the second reflow i.e.to reflow the Top side, voids were observed on the bottom Side BGA (which is designed mirrored to one of the top Side BGA). Being new on this type of assembly, I would appreciate if any of you experts can give me some thought to this.

regards,

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Rama

#29521

Mirrored BGA Assembly | 16 July, 2004

We are going to start producing product that require us to assemble Stacked BGAs. My question - how to rework this package, as the the process of either removing or re-placing them onto the PCB will the effect the BGA sitting on top of it. Pls help.

Rama

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#29536

Mirrored BGA Assembly | 16 July, 2004

on the top of your screen there is a search area. Punch in Voids and hit enter. The first discussion covers the voiding issue very well.

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KEN

#29546

Mirrored BGA Assembly | 18 July, 2004

This is the least desirable method (mirroring).

1. X-ray inspection becomes difficult. I will repeat: x-ray inspection becomes difficult. False fails go up. True fail detection goes down.

2. Remove and replace becomes challenging. You really end up reworking two devices (one intentional and one unintentional).

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