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Reball BGA process flow


Reball BGA process flow | 1 February, 2005

How to rework BGA? what is the process flow and what is the equipment require?

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Reball BGA process flow | 2 February, 2005

Process flow

1.Remove part - It may be necessary to bake assembly prior to removing. 2.Remove remaining solder from part 3.Apply flux to part 4.Apply solder spheres to part 5.Reflow part You may want to bake component before re-installing

6.Apply solder paste *optional to PCBA 7.Apply tack flux to PCBA and part *optional - either 6 or 7 needs to be performed 8.Reflow part onto PCBA 9.Xray for shorts/opens/proper reflow 10.Clean if necessary

Equipment/materials: hot gas or IR rework station for removal and installation of BGA

Bake oven - should be able to hold temps ranging from 90-150 C.

Solder wick - if rework station does not have vacuum solder removal function

Solder iron

Solder spheres - use the correct size that originally was on the part.

Tack Flux - no-clean or water soluble. Use no-clean for any part <1mm pitch.

I recommend that you browse through Winslow automations and minimicrostencil web sites. They have solder preforms, ovens, and other necessary things that can help you with this.

There are many different options when it comes to equipment and proceses.


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Reball BGA process flow | 9 February, 2005


few comments: - what is the criteria to decide if re-ball or not a PBGA? - any electrical test is performed toPBGAs before reball ? - what in case the reballing has been done on a electrical damaged PBGA? In that case the replacement of bad PBGA from PBA would be done two or more time if not luky. - what is the expected reliability of the re-balled PBGA? and solder joint ? - does the customer accept reballed PBGA? - marking of re-balled BGA - what do they say the standards about PBGA reballing ?

Sorry for the "provocatory" questions, but in my experience we reballed only Ceramic BGA, (also Ceramic Column Grid Array) but only after electrical test, this just in order to avoid to reball a bad component. Reballing Plastic BGA was never allowed by our customer.

But because I know many assemblers they reball P-BGA, I would like to know more in order to help myself to better approach this process may be in the future when scrap($) wuld be to expensive.

Thanks a lot

Regards GS

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Reball BGA process flow | 18 February, 2005

This is what we use.

1. we only reball when we experience a manufacturing defect (short, trapped component, etc...)and if the part is expensive

2. No testing is done prior since we only reball parts that have a defective attachment.

4. The reliability of the component if processed correctly should not be affected very much, heat always degrades reliability to some extent. Components should be able to withstand 5 reflows according to IPC. This process accounts for three or 4 if you count the solder removal process from the part.

5. 6. Marking and Customer acceptance can only be answered by you.

i am not aware of any standards for this directly.

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Reball BGA process flow | 21 February, 2005

Thank you Russ for shearing your experience. Regards..........GS

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Reball BGA process flow | 7 July, 2005

I am using pretty often the re-balling Winslow Automation kit for many BGA packages we have to re-ball. When I have started doing this, I've tried to use "BGA REBALLING INSTRUCTION" manual (PR-4048 REV.F), but it didn't work. For some reason, although the preforms were always OK and followed strictly the instructions, the vast majority of the reworked BGA were not successfully reballed.

I have realized in time that the best solution is to spread a thin layer of flux on the preforms as well, not only on the BGA package. Since then, I never had any failure while reballing BGAs.

I am surprised to see that the manual does not recommend this and I bet many people have hard time reballing BGAs just because they don't apply flux on the preforms.

The reballing manual from WinslowAutomation/Solderquik can be found at Regards,


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Reball BGA process flow | 7 July, 2005

I have found that if you place it "upside down" with the paper on the bottom they work very well also. The paper has a tendency to warp during heating which causes the no connects. by adding flux to the preform you are essentially sticking the preform to the part. when running them upside down you are using the weight of the package to keep the paper in place and flat.

Thanks for sharing your knowledge!

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