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PoP parts

Views: 3352

#71940

PoP parts | 11 April, 2014

Hello all,

does any body place PoP parts? We are running them through a regular process(paste place reflow) and we don't have good rates on these. Mostly we observe opens at the sides of the part. We are thinking to purchase a flux feeder, but I wanted to see what are your opinions. Regards, Emil

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#71957

PoP parts | 15 April, 2014

Can you attach a photo of said component?

Reese

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#71958

PoP parts | 15 April, 2014

Here is one from X-ray. It is basically two BGAs one over another.

Attachments:

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#71959

PoP parts | 15 April, 2014

Evtimov,

Are you talking about placing an already built POP package, or about building the POP package at the SMT line?

'hege

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#71963

PoP parts | 16 April, 2014

Hege, The package is already built.

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#71965

PoP parts | 16 April, 2014

OK, POP already done, and you are mounting the POP device. You are seeing opens. Opens at the device/PWB? or opens at the device/device interface? Or possibly both? 'hege

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#71969

PoP parts | 17 April, 2014

Opens are on the device to the PCB - mainly on the edges, that makes me think I get some kind of warping,but even if I bake parts and boards doesn't help. We also tried different reflow profiles - same results. I hear that some people use dip fluxers and other techniques to mount these and I expect to hear from them.

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#71974

PoP parts | 17 April, 2014

And digging a bit further, are the opens at the device level (all the solder on PWB pad, none on device pad) or at the PWB (similar to pillow defect?)

After answering that, I would start thinking about(in this order)paste print quality and consistency, PWB solderability, PWB dimensions, thickness, and how the parts are conveyed through the oven (mesh or edge rail), about oven length, profiling, etc...

Good luck on this, please post when you solve the issue.

'hege

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#71985

PoP parts | 21 April, 2014

The top PoP part is what gets dip fluxed or dip pasted. We have had warping issues with these components before but it is almost always the top part.

My guess would be bad components if your reflow profile and print process is good to go.

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#72038

PoP parts | 30 April, 2014

If you still are considering these PoP opens a possible warpage issue I might be able to help. I work for a company that measures warpage during heating (Akrometrix). I'll try and send you a message with details. I would be curious to hear if this has been fixed. Sometimes warpage is at a problem source, but some other approaches as suggested in this thread can often be used to resolved the surface mount failure without addressing the warpage problem.

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#72040

PoP parts | 30 April, 2014

Thank you all for the posts. From all I read lately I will probably try a different solder paste and if that doesn't work I will go for a flux feeder. I will keep you posted.

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