Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.

SMTnet
»
Electronics Forum
»
IC Solder Voiding

IC Solder Voiding

Subscribe to Thread

Ok, Question for all of you quality inspectors out there. ... - Nov 21, 2019 by scotceltic

Do you mean the void over the vias? That's normal phenomenon... - Nov 21, 2019 by sssamw

I'm worried about the voids that you have on the heel fillet... - Nov 22, 2019 by DWL

Thank you for the response. Nothing in the datasheet referr... - Nov 26, 2019 by scotceltic

I am more worried about those voids also instead of the void... - Nov 26, 2019 by scotceltic

It's hard to tell from the image but it looks like there isn... - Nov 26, 2019 by Steve Thomas

OK, if has concern on void in the function pin area, you nee... - Nov 27, 2019 by sssamw

The short answer is people are still arguing about what the ... - Dec 10, 2019 by SMTA-Norah SMTA

Hi, Below may help you out. per IPC 7093 ( Design and ass... - Dec 11, 2019 by Ameen

Although this is not technically a bottom termination compon... - Dec 11, 2019 by Clockwatcher

Thank you all for the comments. They have been helpful to r... - Dec 11, 2019 by scotceltic

I agree with you in this case. The voids on ground pad of IC... - Dec 20, 2019 by GC_2019

Steve Thomas pointed the right question. Go and verify the d... - Dec 30, 2019 by Evtimov

I do faced this problem and and not solve. Fortunately, did ... - Jan 04, 2020 by SMTA-Davandran SMTA

scotceltic

#83793

IC Solder Voiding | 21 November, 2019

Ok, Question for all of you quality inspectors out there. Would you consider the IC image here to have excessive voiding given the amount of vias ? I only see an IPC voiding spec on BGA balls but nothing for IC's. I'd appreciate all your thoughts ?

Attachments:

reply »

sssamw

#83795

IC Solder Voiding | 21 November, 2019

Do you mean the void over the vias? That's normal phenomenon due to air or solder go into the vias causes void.

You can check the IC datasheet to see if any requirement for solder connecting on the central body grounding area, suggest you have >=50% area soldered.

If you need less void the the grounding area, you can increase solder paste area/volume.

reply »

DWL

#83800

IC Solder Voiding | 22 November, 2019

I'm worried about the voids that you have on the heel fillet of the leads. Off the top of my head, I don't recall if/what the IPC spec is for voids in gull lead fillets is but my gut instinct is that you're compromising the mechanical strength of the solder joint. The heel fillet provides the bulk of the mechanical strength of the joint, and from the image much of that fillet is missing.

reply »

scotceltic

#83812

IC Solder Voiding | 26 November, 2019

Thank you for the response. Nothing in the datasheet referring to a percentage of thermal pad coverage. I am thinking along the same lines. We are not failing any thermal or functional testing as is so am thinking there is no problem here except maybe for the voids in the functional pads.

reply »

scotceltic

#83813

IC Solder Voiding | 26 November, 2019

I am more worried about those voids also instead of the voids in the thermal pads. I still can't find any IPC spec that calls out a min. void percentage other than on BGA packages.

reply »

Steve Thomas

#83817

IC Solder Voiding | 26 November, 2019

It's hard to tell from the image but it looks like there isn't much room for a heel fillet.

Seems like that could contribute to your voiding (or poor wetting) if there isn't enough paste volume there.

reply »

sssamw

#83826

IC Solder Voiding | 27 November, 2019

OK, if has concern on void in the function pin area, you need cross section of the pins solder joints, to see how much area ratio of the void to solder joint area. Of course you need make sure solder joint (the toe and heel, height)meet IPC requirement. And also you can use X-ray image to calculate the void to solder area ratio, suggest the ratio is within 25% is better, the void could reduce solder connecting between the function pin and the solder pad, that's main concern.

reply »

SMTA-Norah

#83916

IC Solder Voiding | 10 December, 2019

The short answer is people are still arguing about what the standard should be. A max voiding between 25-30% depending on who you ask.

Also if those are capped vias they can still cause voids because bubbles are attracted to the irregularities in the plating.

That is a really nice x-ray image BTW, and I agree that the heel voids are really fascinating and more worrisome. I have never seen that covered by the IPC either, I don't even know how one would begin.

This message was posted via the Electronics Forum @ SMTA SMTA

reply »

Ameen

#83921

IC Solder Voiding | 11 December, 2019

Hi,

Below may help you out.

per IPC 7093 ( Design and assembly Process Implementation for Bottom Termination Components ),Clause 6.1.5.3 voids on thermal pad up to 50% does not result in loss of thermal performance. Since the void criteria is meeting IPC ,we are following IPC 7093 which is specific for BTC components.

Regards, Ameen

reply »

Clockwatcher

#83922

IC Solder Voiding | 11 December, 2019

Although this is not technically a bottom termination component, the method of attachment of the thermal pad is a bottom termination attachment. For bottom termination components IPC states that "thermal pad void criteria shall be established between the manufacturer and user". IPC-A-610G page 8-96.

reply »

scotceltic

#83923

IC Solder Voiding | 11 December, 2019

Thank you all for the comments. They have been helpful to reinforce my first thoughts.

reply »

GC_2019

#84001

IC Solder Voiding | 20 December, 2019

I agree with you in this case. The voids on ground pad of IC <=50%

reply »

Evtimov