Popcorning BGA in wave-soldering

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Does anyone have any experience of popcorning BGA�s in wave... - Oct 18, 1999 by MTEK Consulting AB

That should not happen. There are some threads concerning B... - Oct 18, 1999 by Wolfgang Busko

No, but answer me this? 1 What type of BGA? 2 What's the w... - Oct 18, 1999 by davef

Are they visibly "popped" after wave but not before? Remem... - Oct 18, 1999 by John Thorup

We have just completed some studies of with ABPAC, who is a... - Oct 19, 1999 by

MTEK Consulting AB

#8935

Popcorning BGA in wave-soldering | 18 October, 1999

Does anyone have any experience of popcorning BGA�s in wavesoldering?

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Wolfgang Busko

#8936

Re: Popcorning BGA in wave-soldering | 18 October, 1999

That should not happen. There are some threads concerning BGA and wavesoldering you could look for. It�s said that you should protect the vias in the BGA-area by soldermask or at least with tented vias to prevent rereflow of BGAs solderjoints what could lead to open connections. That the heat is that excessive that popcorning occurs is quite new to me but not unlikely. I would say treat the boards with assembled BGA the same way you treat the BGA itself in order to prevent popcorning, try to avoid extended storage between reflow and wave or store under dry conditions to avoid prebake with all disadvantages.

m2c

Wolfgang

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davef

#8937

Re: Popcorning BGA in wave-soldering | 18 October, 1999

No, but answer me this?

1 What type of BGA? 2 What's the wave process, materials and temps? Are you waving the BGA or top-side flowing it? 3 If the BGA is plastic, what are you doing to prevent/remove entrapped moisture before solder processing? 4 What makes you so sure you are distroying these poor defenseless BGAs in the wave?

Good luck

Dave F

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John Thorup

#8938

Re: Popcorning BGA in wave-soldering | 18 October, 1999

Are they visibly "popped" after wave but not before? Remember that many BGAs, especially plastic (PBGA) are very moisture sensitive and even 24 hours or less out of a controlled environment violates exposure rules.

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Stu Leech

#8939

Re: Popcorning BGA in wave-soldering | 19 October, 1999

We have just completed some studies of with ABPAC, who is a large subcontract assembler of plastic ball grid arrays. BT laminates can pick-up appreciable moisture in just two hours. They are using TVP demoisturizing, our product (I apologize for the semi-plug) to reduce the moisture in their devices to significantly lower levels than is attainable with as much as eight hours of convection bake-out.

It goes without saying that the lower the starting moisture content, the longer the product can safely be on the assembly floor without popcorning.

I can send you some of the curves that we derived if you email me at sleech@ix.netcom.com

Stu Leech

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