About White Patches in IC Top Surface

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rajesh14eee Participant Join Date: Jul 2016 Posts: 2	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 Phone Removed - Cr4 Admin
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Mikerho Guru Join Date: Jan 2007 Location: Moses Lake, WA, USA, Thulcandra - The Silent Planet (C.S. Lewis) Posts: 4216 Good Answers: 194	#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? __________________ "Reason is not automatic. Those who deny it cannot be conquered by it. Do not count on them. Leave them alone." - Ayn Rand
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Mikerho Guru Join Date: Jan 2007 Location: Moses Lake, WA, USA, Thulcandra - The Silent Planet (C.S. Lewis) Posts: 4216 Good Answers: 194	#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? __________________ "Reason is not automatic. Those who deny it cannot be conquered by it. Do not count on them. Leave them alone." - Ayn Rand
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rajesh14eee Participant Join Date: Jul 2016 Posts: 2	#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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Mikerho Guru Join Date: Jan 2007 Location: Moses Lake, WA, USA, Thulcandra - The Silent Planet (C.S. Lewis) Posts: 4216 Good Answers: 194	#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? __________________ "Reason is not automatic. Those who deny it cannot be conquered by it. Do not count on them. Leave them alone." - Ayn Rand
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lyn Guru Join Date: Oct 2008 Posts: 42355 Good Answers: 1693	#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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aurizon Guru Join Date: Jun 2006 Location: Toronto Posts: 3968 Good Answers: 120	#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 __________________ Per Ardua Ad Astra
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aurizon (1); lyn (1); Mikerho (3); rajesh14eee (1)

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