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About White Patches in IC Top Surface

07/18/2016 3:27 AM

Hello all ,

We have doing reballing process. We are doing my SMT Process . In that SMT Process we place solder balls on BGA . In Solder Balls BGA , there is flux contamination to be removed . We able to remove the flux contamination by using MEK and Bioact Chemical . It is getting removed well . But at the same time , in IC top surface on the BGA Polarity side , we are facing White Patches . We unable to clean the white surface , but currently we clean the white surface by using eraser . But it is damaging the balls in BGA.

Need to avoid using rubber or eraser , is there any chemical can be used to clean the white surfaceon the polarity side of the bga , and at the same time it should not affect quality .

pls clarrify and give us the solution.

thks

rajesh

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Guru
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#1

Re: About White Patches in IC Top Surface

07/18/2016 1:29 PM

Are these patches appearing ONLY AFTER the reflow process?

Does it appear like this?

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#2
In reply to #1

Re: About White Patches in IC Top Surface

07/18/2016 1:36 PM

If this is what you're talking about, it's likely something with the package material.

Are you following the heating profile parameters recommended in the IC Datasheet?

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#3
In reply to #1

Re: About White Patches in IC Top Surface

07/18/2016 11:20 PM

Thks for the Reply .

After Reflow Process White patches is not formed .

After Reflow Process flux around the balls is desposited . We need clean them . So that we are using Chemical like MEK and Bioact . After cleaning with the Chemical all flux residues have been cleaned .

after this process by the combination of the chemical there is white patches formed in top of the ic looks like same in the photo you have seen .

how to clean this , pls specify the clean process.

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#5
In reply to #3

Re: About White Patches in IC Top Surface

07/19/2016 10:52 AM

So, I was right, except the patches do not show up until AFTER the cleaning process.

Have you talked with your chip supplier/manufacturer?

It would really help if you posted a photo.

Why did you post off-topic?

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#4

Re: About White Patches in IC Top Surface

07/18/2016 11:50 PM

Check with ardinesh07.

He's probably in the next room.

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#6

Re: About White Patches in IC Top Surface

07/19/2016 11:46 AM

It seems as if the MEK and/or the other cleaning chemical is dissolving some component of the chip package. Does the same happen on the hidden surfaces?

You might try using a water soluble flux, which can be cleaned with water and/or alcohol

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